Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

35 files changed, 12763 insertions, 0 deletions

diff --git a/net/dccp/Kconfig b/net/dccp/Kconfig
new file mode 100644
index 0000000..7aa2a7a
--- /dev/null
+++ b/net/dccp/Kconfig
@@ -0,0 +1,64 @@
+menuconfig IP_DCCP
+	tristate "The DCCP Protocol (EXPERIMENTAL)"
+	depends on INET && EXPERIMENTAL
+	select IP_DCCP_CCID2
+	---help---
+	  Datagram Congestion Control Protocol (RFC 4340)
+
+	  From http://www.ietf.org/rfc/rfc4340.txt:
+
+	  The Datagram Congestion Control Protocol (DCCP) is a transport
+	  protocol that implements bidirectional, unicast connections of
+	  congestion-controlled, unreliable datagrams. It should be suitable
+	  for use by applications such as streaming media, Internet telephony,
+	  and on-line games.
+
+	  To compile this protocol support as a module, choose M here: the
+	  module will be called dccp.
+
+	  If in doubt, say N.
+
+if IP_DCCP
+
+config INET_DCCP_DIAG
+	depends on INET_DIAG
+	def_tristate y if (IP_DCCP = y && INET_DIAG = y)
+	def_tristate m
+
+config IP_DCCP_ACKVEC
+	bool
+
+source "net/dccp/ccids/Kconfig"
+
+menu "DCCP Kernel Hacking"
+	depends on DEBUG_KERNEL=y
+
+config IP_DCCP_DEBUG
+	bool "DCCP debug messages"
+	---help---
+	  Only use this if you're hacking DCCP.
+
+	  When compiling DCCP as a module, this debugging output can be toggled
+	  by setting the parameter dccp_debug of the `dccp' module to 0 or 1.
+
+	  Just say N.
+
+config NET_DCCPPROBE
+	tristate "DCCP connection probing"
+	depends on PROC_FS && KPROBES
+	---help---
+	This module allows for capturing the changes to DCCP connection
+	state in response to incoming packets. It is used for debugging
+	DCCP congestion avoidance modules. If you don't understand
+	what was just said, you don't need it: say N.
+
+	Documentation on how to use DCCP connection probing can be found
+	at http://linux-net.osdl.org/index.php/DccpProbe
+
+	To compile this code as a module, choose M here: the
+	module will be called dccp_probe.
+
+
+endmenu
+
+endif # IP_DDCP
diff --git a/net/dccp/Makefile b/net/dccp/Makefile
new file mode 100644
index 0000000..f4f8793
--- /dev/null
+++ b/net/dccp/Makefile
@@ -0,0 +1,21 @@
+obj-$(CONFIG_IP_DCCP) += dccp.o dccp_ipv4.o
+
+dccp-y := ccid.o feat.o input.o minisocks.o options.o output.o proto.o timer.o
+
+dccp_ipv4-y := ipv4.o
+
+# build dccp_ipv6 as module whenever either IPv6 or DCCP is a module
+obj-$(subst y,$(CONFIG_IP_DCCP),$(CONFIG_IPV6)) += dccp_ipv6.o
+dccp_ipv6-y := ipv6.o
+
+dccp-$(CONFIG_IP_DCCP_ACKVEC) += ackvec.o
+
+obj-$(CONFIG_INET_DCCP_DIAG) += dccp_diag.o
+obj-$(CONFIG_NET_DCCPPROBE) += dccp_probe.o
+
+dccp-$(CONFIG_SYSCTL) += sysctl.o
+
+dccp_diag-y := diag.o
+dccp_probe-y := probe.o
+
+obj-y += ccids/
diff --git a/net/dccp/ackvec.c b/net/dccp/ackvec.c
new file mode 100644
index 0000000..1e8be24
--- /dev/null
+++ b/net/dccp/ackvec.c
@@ -0,0 +1,479 @@
+/*
+ *  net/dccp/ackvec.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
+ *
+ *      This program is free software; you can redistribute it and/or modify it
+ *      under the terms of the GNU General Public License as published by the
+ *      Free Software Foundation; version 2 of the License;
+ */
+
+#include "ackvec.h"
+#include "dccp.h"
+
+#include <linux/dccp.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+
+#include <net/sock.h>
+
+static struct kmem_cache *dccp_ackvec_slab;
+static struct kmem_cache *dccp_ackvec_record_slab;
+
+static struct dccp_ackvec_record *dccp_ackvec_record_new(void)
+{
+	struct dccp_ackvec_record *avr =
+			kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);
+
+	if (avr != NULL)
+		INIT_LIST_HEAD(&avr->avr_node);
+
+	return avr;
+}
+
+static void dccp_ackvec_record_delete(struct dccp_ackvec_record *avr)
+{
+	if (unlikely(avr == NULL))
+		return;
+	/* Check if deleting a linked record */
+	WARN_ON(!list_empty(&avr->avr_node));
+	kmem_cache_free(dccp_ackvec_record_slab, avr);
+}
+
+static void dccp_ackvec_insert_avr(struct dccp_ackvec *av,
+				   struct dccp_ackvec_record *avr)
+{
+	/*
+	 * AVRs are sorted by seqno. Since we are sending them in order, we
+	 * just add the AVR at the head of the list.
+	 * -sorbo.
+	 */
+	if (!list_empty(&av->av_records)) {
+		const struct dccp_ackvec_record *head =
+					list_entry(av->av_records.next,
+						   struct dccp_ackvec_record,
+						   avr_node);
+		BUG_ON(before48(avr->avr_ack_seqno, head->avr_ack_seqno));
+	}
+
+	list_add(&avr->avr_node, &av->av_records);
+}
+
+int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
+	/* Figure out how many options do we need to represent the ackvec */
+	const u16 nr_opts = DIV_ROUND_UP(av->av_vec_len, DCCP_MAX_ACKVEC_OPT_LEN);
+	u16 len = av->av_vec_len + 2 * nr_opts, i;
+	u32 elapsed_time;
+	const unsigned char *tail, *from;
+	unsigned char *to;
+	struct dccp_ackvec_record *avr;
+	suseconds_t delta;
+
+	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
+		return -1;
+
+	delta = ktime_us_delta(ktime_get_real(), av->av_time);
+	elapsed_time = delta / 10;
+
+	if (elapsed_time != 0 &&
+	    dccp_insert_option_elapsed_time(sk, skb, elapsed_time))
+		return -1;
+
+	avr = dccp_ackvec_record_new();
+	if (avr == NULL)
+		return -1;
+
+	DCCP_SKB_CB(skb)->dccpd_opt_len += len;
+
+	to   = skb_push(skb, len);
+	len  = av->av_vec_len;
+	from = av->av_buf + av->av_buf_head;
+	tail = av->av_buf + DCCP_MAX_ACKVEC_LEN;
+
+	for (i = 0; i < nr_opts; ++i) {
+		int copylen = len;
+
+		if (len > DCCP_MAX_ACKVEC_OPT_LEN)
+			copylen = DCCP_MAX_ACKVEC_OPT_LEN;
+
+		*to++ = DCCPO_ACK_VECTOR_0;
+		*to++ = copylen + 2;
+
+		/* Check if buf_head wraps */
+		if (from + copylen > tail) {
+			const u16 tailsize = tail - from;
+
+			memcpy(to, from, tailsize);
+			to	+= tailsize;
+			len	-= tailsize;
+			copylen	-= tailsize;
+			from	= av->av_buf;
+		}
+
+		memcpy(to, from, copylen);
+		from += copylen;
+		to   += copylen;
+		len  -= copylen;
+	}
+
+	/*
+	 *	From RFC 4340, A.2:
+	 *
+	 *	For each acknowledgement it sends, the HC-Receiver will add an
+	 *	acknowledgement record.  ack_seqno will equal the HC-Receiver
+	 *	sequence number it used for the ack packet; ack_ptr will equal
+	 *	buf_head; ack_ackno will equal buf_ackno; and ack_nonce will
+	 *	equal buf_nonce.
+	 */
+	avr->avr_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
+	avr->avr_ack_ptr   = av->av_buf_head;
+	avr->avr_ack_ackno = av->av_buf_ackno;
+	avr->avr_ack_nonce = av->av_buf_nonce;
+	avr->avr_sent_len  = av->av_vec_len;
+
+	dccp_ackvec_insert_avr(av, avr);
+
+	dccp_pr_debug("%s ACK Vector 0, len=%d, ack_seqno=%llu, "
+		      "ack_ackno=%llu\n",
+		      dccp_role(sk), avr->avr_sent_len,
+		      (unsigned long long)avr->avr_ack_seqno,
+		      (unsigned long long)avr->avr_ack_ackno);
+	return 0;
+}
+
+struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
+{
+	struct dccp_ackvec *av = kmem_cache_alloc(dccp_ackvec_slab, priority);
+
+	if (av != NULL) {
+		av->av_buf_head	 = DCCP_MAX_ACKVEC_LEN - 1;
+		av->av_buf_ackno = UINT48_MAX + 1;
+		av->av_buf_nonce = 0;
+		av->av_time	 = ktime_set(0, 0);
+		av->av_vec_len	 = 0;
+		INIT_LIST_HEAD(&av->av_records);
+	}
+
+	return av;
+}
+
+void dccp_ackvec_free(struct dccp_ackvec *av)
+{
+	if (unlikely(av == NULL))
+		return;
+
+	if (!list_empty(&av->av_records)) {
+		struct dccp_ackvec_record *avr, *next;
+
+		list_for_each_entry_safe(avr, next, &av->av_records, avr_node) {
+			list_del_init(&avr->avr_node);
+			dccp_ackvec_record_delete(avr);
+		}
+	}
+
+	kmem_cache_free(dccp_ackvec_slab, av);
+}
+
+static inline u8 dccp_ackvec_state(const struct dccp_ackvec *av,
+				   const u32 index)
+{
+	return av->av_buf[index] & DCCP_ACKVEC_STATE_MASK;
+}
+
+static inline u8 dccp_ackvec_len(const struct dccp_ackvec *av,
+				 const u32 index)
+{
+	return av->av_buf[index] & DCCP_ACKVEC_LEN_MASK;
+}
+
+/*
+ * If several packets are missing, the HC-Receiver may prefer to enter multiple
+ * bytes with run length 0, rather than a single byte with a larger run length;
+ * this simplifies table updates if one of the missing packets arrives.
+ */
+static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av,
+						 const unsigned int packets,
+						 const unsigned char state)
+{
+	unsigned int gap;
+	long new_head;
+
+	if (av->av_vec_len + packets > DCCP_MAX_ACKVEC_LEN)
+		return -ENOBUFS;
+
+	gap	 = packets - 1;
+	new_head = av->av_buf_head - packets;
+
+	if (new_head < 0) {
+		if (gap > 0) {
+			memset(av->av_buf, DCCP_ACKVEC_STATE_NOT_RECEIVED,
+			       gap + new_head + 1);
+			gap = -new_head;
+		}
+		new_head += DCCP_MAX_ACKVEC_LEN;
+	}
+
+	av->av_buf_head = new_head;
+
+	if (gap > 0)
+		memset(av->av_buf + av->av_buf_head + 1,
+		       DCCP_ACKVEC_STATE_NOT_RECEIVED, gap);
+
+	av->av_buf[av->av_buf_head] = state;
+	av->av_vec_len += packets;
+	return 0;
+}
+
+/*
+ * Implements the RFC 4340, Appendix A
+ */
+int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
+		    const u64 ackno, const u8 state)
+{
+	/*
+	 * Check at the right places if the buffer is full, if it is, tell the
+	 * caller to start dropping packets till the HC-Sender acks our ACK
+	 * vectors, when we will free up space in av_buf.
+	 *
+	 * We may well decide to do buffer compression, etc, but for now lets
+	 * just drop.
+	 *
+	 * From Appendix A.1.1 (`New Packets'):
+	 *
+	 *	Of course, the circular buffer may overflow, either when the
+	 *	HC-Sender is sending data at a very high rate, when the
+	 *	HC-Receiver's acknowledgements are not reaching the HC-Sender,
+	 *	or when the HC-Sender is forgetting to acknowledge those acks
+	 *	(so the HC-Receiver is unable to clean up old state). In this
+	 *	case, the HC-Receiver should either compress the buffer (by
+	 *	increasing run lengths when possible), transfer its state to
+	 *	a larger buffer, or, as a last resort, drop all received
+	 *	packets, without processing them whatsoever, until its buffer
+	 *	shrinks again.
+	 */
+
+	/* See if this is the first ackno being inserted */
+	if (av->av_vec_len == 0) {
+		av->av_buf[av->av_buf_head] = state;
+		av->av_vec_len = 1;
+	} else if (after48(ackno, av->av_buf_ackno)) {
+		const u64 delta = dccp_delta_seqno(av->av_buf_ackno, ackno);
+
+		/*
+		 * Look if the state of this packet is the same as the
+		 * previous ackno and if so if we can bump the head len.
+		 */
+		if (delta == 1 &&
+		    dccp_ackvec_state(av, av->av_buf_head) == state &&
+		    dccp_ackvec_len(av, av->av_buf_head) < DCCP_ACKVEC_LEN_MASK)
+			av->av_buf[av->av_buf_head]++;
+		else if (dccp_ackvec_set_buf_head_state(av, delta, state))
+			return -ENOBUFS;
+	} else {
+		/*
+		 * A.1.2.  Old Packets
+		 *
+		 *	When a packet with Sequence Number S <= buf_ackno
+		 *	arrives, the HC-Receiver will scan the table for
+		 *	the byte corresponding to S. (Indexing structures
+		 *	could reduce the complexity of this scan.)
+		 */
+		u64 delta = dccp_delta_seqno(ackno, av->av_buf_ackno);
+		u32 index = av->av_buf_head;
+
+		while (1) {
+			const u8 len = dccp_ackvec_len(av, index);
+			const u8 av_state = dccp_ackvec_state(av, index);
+			/*
+			 * valid packets not yet in av_buf have a reserved
+			 * entry, with a len equal to 0.
+			 */
+			if (av_state == DCCP_ACKVEC_STATE_NOT_RECEIVED &&
+			    len == 0 && delta == 0) { /* Found our
+							 reserved seat! */
+				dccp_pr_debug("Found %llu reserved seat!\n",
+					      (unsigned long long)ackno);
+				av->av_buf[index] = state;
+				goto out;
+			}
+			/* len == 0 means one packet */
+			if (delta < len + 1)
+				goto out_duplicate;
+
+			delta -= len + 1;
+			if (++index == DCCP_MAX_ACKVEC_LEN)
+				index = 0;
+		}
+	}
+
+	av->av_buf_ackno = ackno;
+	av->av_time = ktime_get_real();
+out:
+	return 0;
+
+out_duplicate:
+	/* Duplicate packet */
+	dccp_pr_debug("Received a dup or already considered lost "
+		      "packet: %llu\n", (unsigned long long)ackno);
+	return -EILSEQ;
+}
+
+static void dccp_ackvec_throw_record(struct dccp_ackvec *av,
+				     struct dccp_ackvec_record *avr)
+{
+	struct dccp_ackvec_record *next;
+
+	/* sort out vector length */
+	if (av->av_buf_head <= avr->avr_ack_ptr)
+		av->av_vec_len = avr->avr_ack_ptr - av->av_buf_head;
+	else
+		av->av_vec_len = DCCP_MAX_ACKVEC_LEN - 1 -
+				 av->av_buf_head + avr->avr_ack_ptr;
+
+	/* free records */
+	list_for_each_entry_safe_from(avr, next, &av->av_records, avr_node) {
+		list_del_init(&avr->avr_node);
+		dccp_ackvec_record_delete(avr);
+	}
+}
+
+void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk,
+				 const u64 ackno)
+{
+	struct dccp_ackvec_record *avr;
+
+	/*
+	 * If we traverse backwards, it should be faster when we have large
+	 * windows. We will be receiving ACKs for stuff we sent a while back
+	 * -sorbo.
+	 */
+	list_for_each_entry_reverse(avr, &av->av_records, avr_node) {
+		if (ackno == avr->avr_ack_seqno) {
+			dccp_pr_debug("%s ACK packet 0, len=%d, ack_seqno=%llu, "
+				      "ack_ackno=%llu, ACKED!\n",
+				      dccp_role(sk), 1,
+				      (unsigned long long)avr->avr_ack_seqno,
+				      (unsigned long long)avr->avr_ack_ackno);
+			dccp_ackvec_throw_record(av, avr);
+			break;
+		} else if (avr->avr_ack_seqno > ackno)
+			break; /* old news */
+	}
+}
+
+static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
+					    struct sock *sk, u64 *ackno,
+					    const unsigned char len,
+					    const unsigned char *vector)
+{
+	unsigned char i;
+	struct dccp_ackvec_record *avr;
+
+	/* Check if we actually sent an ACK vector */
+	if (list_empty(&av->av_records))
+		return;
+
+	i = len;
+	/*
+	 * XXX
+	 * I think it might be more efficient to work backwards. See comment on
+	 * rcv_ackno. -sorbo.
+	 */
+	avr = list_entry(av->av_records.next, struct dccp_ackvec_record, avr_node);
+	while (i--) {
+		const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
+		u64 ackno_end_rl;
+
+		dccp_set_seqno(&ackno_end_rl, *ackno - rl);
+
+		/*
+		 * If our AVR sequence number is greater than the ack, go
+		 * forward in the AVR list until it is not so.
+		 */
+		list_for_each_entry_from(avr, &av->av_records, avr_node) {
+			if (!after48(avr->avr_ack_seqno, *ackno))
+				goto found;
+		}
+		/* End of the av_records list, not found, exit */
+		break;
+found:
+		if (between48(avr->avr_ack_seqno, ackno_end_rl, *ackno)) {
+			const u8 state = *vector & DCCP_ACKVEC_STATE_MASK;
+			if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) {
+				dccp_pr_debug("%s ACK vector 0, len=%d, "
+					      "ack_seqno=%llu, ack_ackno=%llu, "
+					      "ACKED!\n",
+					      dccp_role(sk), len,
+					      (unsigned long long)
+					      avr->avr_ack_seqno,
+					      (unsigned long long)
+					      avr->avr_ack_ackno);
+				dccp_ackvec_throw_record(av, avr);
+				break;
+			}
+			/*
+			 * If it wasn't received, continue scanning... we might
+			 * find another one.
+			 */
+		}
+
+		dccp_set_seqno(ackno, ackno_end_rl - 1);
+		++vector;
+	}
+}
+
+int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
+		      u64 *ackno, const u8 opt, const u8 *value, const u8 len)
+{
+	if (len > DCCP_MAX_ACKVEC_OPT_LEN)
+		return -1;
+
+	/* dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, value, len); */
+	dccp_ackvec_check_rcv_ackvector(dccp_sk(sk)->dccps_hc_rx_ackvec, sk,
+					ackno, len, value);
+	return 0;
+}
+
+int __init dccp_ackvec_init(void)
+{
+	dccp_ackvec_slab = kmem_cache_create("dccp_ackvec",
+					     sizeof(struct dccp_ackvec), 0,
+					     SLAB_HWCACHE_ALIGN, NULL);
+	if (dccp_ackvec_slab == NULL)
+		goto out_err;
+
+	dccp_ackvec_record_slab =
+			kmem_cache_create("dccp_ackvec_record",
+					  sizeof(struct dccp_ackvec_record),
+					  0, SLAB_HWCACHE_ALIGN, NULL);
+	if (dccp_ackvec_record_slab == NULL)
+		goto out_destroy_slab;
+
+	return 0;
+
+out_destroy_slab:
+	kmem_cache_destroy(dccp_ackvec_slab);
+	dccp_ackvec_slab = NULL;
+out_err:
+	DCCP_CRIT("Unable to create Ack Vector slab cache");
+	return -ENOBUFS;
+}
+
+void dccp_ackvec_exit(void)
+{
+	if (dccp_ackvec_slab != NULL) {
+		kmem_cache_destroy(dccp_ackvec_slab);
+		dccp_ackvec_slab = NULL;
+	}
+	if (dccp_ackvec_record_slab != NULL) {
+		kmem_cache_destroy(dccp_ackvec_record_slab);
+		dccp_ackvec_record_slab = NULL;
+	}
+}
diff --git a/net/dccp/ackvec.h b/net/dccp/ackvec.h
new file mode 100644
index 0000000..bcb64fb
--- /dev/null
+++ b/net/dccp/ackvec.h
@@ -0,0 +1,158 @@
+#ifndef _ACKVEC_H
+#define _ACKVEC_H
+/*
+ *  net/dccp/ackvec.h
+ *
+ *  An implementation of the DCCP protocol
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com>
+ *
+ *	This program is free software; you can redistribute it and/or modify it
+ *	under the terms of the GNU General Public License version 2 as
+ *	published by the Free Software Foundation.
+ */
+
+#include <linux/compiler.h>
+#include <linux/ktime.h>
+#include <linux/list.h>
+#include <linux/types.h>
+
+/* Read about the ECN nonce to see why it is 253 */
+#define DCCP_MAX_ACKVEC_OPT_LEN 253
+/* We can spread an ack vector across multiple options */
+#define DCCP_MAX_ACKVEC_LEN (DCCP_MAX_ACKVEC_OPT_LEN * 2)
+
+#define DCCP_ACKVEC_STATE_RECEIVED	0
+#define DCCP_ACKVEC_STATE_ECN_MARKED	(1 << 6)
+#define DCCP_ACKVEC_STATE_NOT_RECEIVED	(3 << 6)
+
+#define DCCP_ACKVEC_STATE_MASK		0xC0 /* 11000000 */
+#define DCCP_ACKVEC_LEN_MASK		0x3F /* 00111111 */
+
+/** struct dccp_ackvec - ack vector
+ *
+ * This data structure is the one defined in RFC 4340, Appendix A.
+ *
+ * @av_buf_head - circular buffer head
+ * @av_buf_tail - circular buffer tail
+ * @av_buf_ackno - ack # of the most recent packet acknowledgeable in the
+ *		       buffer (i.e. %av_buf_head)
+ * @av_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked
+ * 		       by the buffer with State 0
+ *
+ * Additionally, the HC-Receiver must keep some information about the
+ * Ack Vectors it has recently sent. For each packet sent carrying an
+ * Ack Vector, it remembers four variables:
+ *
+ * @av_records - list of dccp_ackvec_record
+ * @av_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
+ *
+ * @av_time - the time in usecs
+ * @av_buf - circular buffer of acknowledgeable packets
+ */
+struct dccp_ackvec {
+	u64			av_buf_ackno;
+	struct list_head	av_records;
+	ktime_t			av_time;
+	u16			av_buf_head;
+	u16			av_vec_len;
+	u8			av_buf_nonce;
+	u8			av_ack_nonce;
+	u8			av_buf[DCCP_MAX_ACKVEC_LEN];
+};
+
+/** struct dccp_ackvec_record - ack vector record
+ *
+ * ACK vector record as defined in Appendix A of spec.
+ *
+ * The list is sorted by avr_ack_seqno
+ *
+ * @avr_node - node in av_records
+ * @avr_ack_seqno - sequence number of the packet this record was sent on
+ * @avr_ack_ackno - sequence number being acknowledged
+ * @avr_ack_ptr - pointer into av_buf where this record starts
+ * @avr_ack_nonce - av_ack_nonce at the time this record was sent
+ * @avr_sent_len - lenght of the record in av_buf
+ */
+struct dccp_ackvec_record {
+	struct list_head avr_node;
+	u64		 avr_ack_seqno;
+	u64		 avr_ack_ackno;
+	u16		 avr_ack_ptr;
+	u16		 avr_sent_len;
+	u8		 avr_ack_nonce;
+};
+
+struct sock;
+struct sk_buff;
+
+#ifdef CONFIG_IP_DCCP_ACKVEC
+extern int dccp_ackvec_init(void);
+extern void dccp_ackvec_exit(void);
+
+extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority);
+extern void dccp_ackvec_free(struct dccp_ackvec *av);
+
+extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
+			   const u64 ackno, const u8 state);
+
+extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
+					struct sock *sk, const u64 ackno);
+extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
+			     u64 *ackno, const u8 opt,
+			     const u8 *value, const u8 len);
+
+extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
+
+static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
+{
+	return av->av_vec_len;
+}
+#else /* CONFIG_IP_DCCP_ACKVEC */
+static inline int dccp_ackvec_init(void)
+{
+	return 0;
+}
+
+static inline void dccp_ackvec_exit(void)
+{
+}
+
+static inline struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
+{
+	return NULL;
+}
+
+static inline void dccp_ackvec_free(struct dccp_ackvec *av)
+{
+}
+
+static inline int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
+				  const u64 ackno, const u8 state)
+{
+	return -1;
+}
+
+static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
+					       struct sock *sk, const u64 ackno)
+{
+}
+
+static inline int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
+				    const u64 *ackno, const u8 opt,
+				    const u8 *value, const u8 len)
+{
+	return -1;
+}
+
+static inline int dccp_insert_option_ackvec(const struct sock *sk,
+					    const struct sk_buff *skb)
+{
+	return -1;
+}
+
+static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
+{
+	return 0;
+}
+#endif /* CONFIG_IP_DCCP_ACKVEC */
+#endif /* _ACKVEC_H */
diff --git a/net/dccp/ccid.c b/net/dccp/ccid.c
new file mode 100644
index 0000000..8fe931a
--- /dev/null
+++ b/net/dccp/ccid.c
@@ -0,0 +1,257 @@
+/*
+ *  net/dccp/ccid.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  CCID infrastructure
+ *
+ *	This program is free software; you can redistribute it and/or modify it
+ *	under the terms of the GNU General Public License version 2 as
+ *	published by the Free Software Foundation.
+ */
+
+#include "ccid.h"
+
+static struct ccid_operations *ccids[CCID_MAX];
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
+static atomic_t ccids_lockct = ATOMIC_INIT(0);
+static DEFINE_SPINLOCK(ccids_lock);
+
+/*
+ * The strategy is: modifications ccids vector are short, do not sleep and
+ * veeery rare, but read access should be free of any exclusive locks.
+ */
+static void ccids_write_lock(void)
+{
+	spin_lock(&ccids_lock);
+	while (atomic_read(&ccids_lockct) != 0) {
+		spin_unlock(&ccids_lock);
+		yield();
+		spin_lock(&ccids_lock);
+	}
+}
+
+static inline void ccids_write_unlock(void)
+{
+	spin_unlock(&ccids_lock);
+}
+
+static inline void ccids_read_lock(void)
+{
+	atomic_inc(&ccids_lockct);
+	smp_mb__after_atomic_inc();
+	spin_unlock_wait(&ccids_lock);
+}
+
+static inline void ccids_read_unlock(void)
+{
+	atomic_dec(&ccids_lockct);
+}
+
+#else
+#define ccids_write_lock() do { } while(0)
+#define ccids_write_unlock() do { } while(0)
+#define ccids_read_lock() do { } while(0)
+#define ccids_read_unlock() do { } while(0)
+#endif
+
+static struct kmem_cache *ccid_kmem_cache_create(int obj_size, const char *fmt,...)
+{
+	struct kmem_cache *slab;
+	char slab_name_fmt[32], *slab_name;
+	va_list args;
+
+	va_start(args, fmt);
+	vsnprintf(slab_name_fmt, sizeof(slab_name_fmt), fmt, args);
+	va_end(args);
+
+	slab_name = kstrdup(slab_name_fmt, GFP_KERNEL);
+	if (slab_name == NULL)
+		return NULL;
+	slab = kmem_cache_create(slab_name, sizeof(struct ccid) + obj_size, 0,
+				 SLAB_HWCACHE_ALIGN, NULL);
+	if (slab == NULL)
+		kfree(slab_name);
+	return slab;
+}
+
+static void ccid_kmem_cache_destroy(struct kmem_cache *slab)
+{
+	if (slab != NULL) {
+		const char *name = kmem_cache_name(slab);
+
+		kmem_cache_destroy(slab);
+		kfree(name);
+	}
+}
+
+int ccid_register(struct ccid_operations *ccid_ops)
+{
+	int err = -ENOBUFS;
+
+	ccid_ops->ccid_hc_rx_slab =
+			ccid_kmem_cache_create(ccid_ops->ccid_hc_rx_obj_size,
+					       "ccid%u_hc_rx_sock",
+					       ccid_ops->ccid_id);
+	if (ccid_ops->ccid_hc_rx_slab == NULL)
+		goto out;
+
+	ccid_ops->ccid_hc_tx_slab =
+			ccid_kmem_cache_create(ccid_ops->ccid_hc_tx_obj_size,
+					       "ccid%u_hc_tx_sock",
+					       ccid_ops->ccid_id);
+	if (ccid_ops->ccid_hc_tx_slab == NULL)
+		goto out_free_rx_slab;
+
+	ccids_write_lock();
+	err = -EEXIST;
+	if (ccids[ccid_ops->ccid_id] == NULL) {
+		ccids[ccid_ops->ccid_id] = ccid_ops;
+		err = 0;
+	}
+	ccids_write_unlock();
+	if (err != 0)
+		goto out_free_tx_slab;
+
+	pr_info("CCID: Registered CCID %d (%s)\n",
+		ccid_ops->ccid_id, ccid_ops->ccid_name);
+out:
+	return err;
+out_free_tx_slab:
+	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
+	ccid_ops->ccid_hc_tx_slab = NULL;
+	goto out;
+out_free_rx_slab:
+	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
+	ccid_ops->ccid_hc_rx_slab = NULL;
+	goto out;
+}
+
+EXPORT_SYMBOL_GPL(ccid_register);
+
+int ccid_unregister(struct ccid_operations *ccid_ops)
+{
+	ccids_write_lock();
+	ccids[ccid_ops->ccid_id] = NULL;
+	ccids_write_unlock();
+
+	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
+	ccid_ops->ccid_hc_tx_slab = NULL;
+	ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
+	ccid_ops->ccid_hc_rx_slab = NULL;
+
+	pr_info("CCID: Unregistered CCID %d (%s)\n",
+		ccid_ops->ccid_id, ccid_ops->ccid_name);
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(ccid_unregister);
+
+struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx, gfp_t gfp)
+{
+	struct ccid_operations *ccid_ops;
+	struct ccid *ccid = NULL;
+
+	ccids_read_lock();
+#ifdef CONFIG_MODULES
+	if (ccids[id] == NULL) {
+		/* We only try to load if in process context */
+		ccids_read_unlock();
+		if (gfp & GFP_ATOMIC)
+			goto out;
+		request_module("net-dccp-ccid-%d", id);
+		ccids_read_lock();
+	}
+#endif
+	ccid_ops = ccids[id];
+	if (ccid_ops == NULL)
+		goto out_unlock;
+
+	if (!try_module_get(ccid_ops->ccid_owner))
+		goto out_unlock;
+
+	ccids_read_unlock();
+
+	ccid = kmem_cache_alloc(rx ? ccid_ops->ccid_hc_rx_slab :
+				     ccid_ops->ccid_hc_tx_slab, gfp);
+	if (ccid == NULL)
+		goto out_module_put;
+	ccid->ccid_ops = ccid_ops;
+	if (rx) {
+		memset(ccid + 1, 0, ccid_ops->ccid_hc_rx_obj_size);
+		if (ccid->ccid_ops->ccid_hc_rx_init != NULL &&
+		    ccid->ccid_ops->ccid_hc_rx_init(ccid, sk) != 0)
+			goto out_free_ccid;
+	} else {
+		memset(ccid + 1, 0, ccid_ops->ccid_hc_tx_obj_size);
+		if (ccid->ccid_ops->ccid_hc_tx_init != NULL &&
+		    ccid->ccid_ops->ccid_hc_tx_init(ccid, sk) != 0)
+			goto out_free_ccid;
+	}
+out:
+	return ccid;
+out_unlock:
+	ccids_read_unlock();
+	goto out;
+out_free_ccid:
+	kmem_cache_free(rx ? ccid_ops->ccid_hc_rx_slab :
+			ccid_ops->ccid_hc_tx_slab, ccid);
+	ccid = NULL;
+out_module_put:
+	module_put(ccid_ops->ccid_owner);
+	goto out;
+}
+
+EXPORT_SYMBOL_GPL(ccid_new);
+
+struct ccid *ccid_hc_rx_new(unsigned char id, struct sock *sk, gfp_t gfp)
+{
+	return ccid_new(id, sk, 1, gfp);
+}
+
+EXPORT_SYMBOL_GPL(ccid_hc_rx_new);
+
+struct ccid *ccid_hc_tx_new(unsigned char id,struct sock *sk,  gfp_t gfp)
+{
+	return ccid_new(id, sk, 0, gfp);
+}
+
+EXPORT_SYMBOL_GPL(ccid_hc_tx_new);
+
+static void ccid_delete(struct ccid *ccid, struct sock *sk, int rx)
+{
+	struct ccid_operations *ccid_ops;
+
+	if (ccid == NULL)
+		return;
+
+	ccid_ops = ccid->ccid_ops;
+	if (rx) {
+		if (ccid_ops->ccid_hc_rx_exit != NULL)
+			ccid_ops->ccid_hc_rx_exit(sk);
+		kmem_cache_free(ccid_ops->ccid_hc_rx_slab,  ccid);
+	} else {
+		if (ccid_ops->ccid_hc_tx_exit != NULL)
+			ccid_ops->ccid_hc_tx_exit(sk);
+		kmem_cache_free(ccid_ops->ccid_hc_tx_slab,  ccid);
+	}
+	ccids_read_lock();
+	if (ccids[ccid_ops->ccid_id] != NULL)
+		module_put(ccid_ops->ccid_owner);
+	ccids_read_unlock();
+}
+
+void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk)
+{
+	ccid_delete(ccid, sk, 1);
+}
+
+EXPORT_SYMBOL_GPL(ccid_hc_rx_delete);
+
+void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk)
+{
+	ccid_delete(ccid, sk, 0);
+}
+
+EXPORT_SYMBOL_GPL(ccid_hc_tx_delete);
diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h
new file mode 100644
index 0000000..fdeae7b
--- /dev/null
+++ b/net/dccp/ccid.h
@@ -0,0 +1,213 @@
+#ifndef _CCID_H
+#define _CCID_H
+/*
+ *  net/dccp/ccid.h
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  CCID infrastructure
+ *
+ *	This program is free software; you can redistribute it and/or modify it
+ *	under the terms of the GNU General Public License version 2 as
+ *	published by the Free Software Foundation.
+ */
+
+#include <net/sock.h>
+#include <linux/compiler.h>
+#include <linux/dccp.h>
+#include <linux/list.h>
+#include <linux/module.h>
+
+#define CCID_MAX 255
+
+struct tcp_info;
+
+/**
+ *  struct ccid_operations  -  Interface to Congestion-Control Infrastructure
+ *
+ *  @ccid_id: numerical CCID ID (up to %CCID_MAX, cf. table 5 in RFC 4340, 10.)
+ *  @ccid_ccmps: the CCMPS including network/transport headers (0 when disabled)
+ *  @ccid_name: alphabetical identifier string for @ccid_id
+ *  @ccid_owner: module which implements/owns this CCID
+ *  @ccid_hc_{r,t}x_slab: memory pool for the receiver/sender half-connection
+ *  @ccid_hc_{r,t}x_obj_size: size of the receiver/sender half-connection socket
+ *
+ *  @ccid_hc_{r,t}x_init: CCID-specific initialisation routine (before startup)
+ *  @ccid_hc_{r,t}x_exit: CCID-specific cleanup routine (before destruction)
+ *  @ccid_hc_rx_packet_recv: implements the HC-receiver side
+ *  @ccid_hc_{r,t}x_parse_options: parsing routine for CCID/HC-specific options
+ *  @ccid_hc_{r,t}x_insert_options: insert routine for CCID/HC-specific options
+ *  @ccid_hc_tx_packet_recv: implements feedback processing for the HC-sender
+ *  @ccid_hc_tx_send_packet: implements the sending part of the HC-sender
+ *  @ccid_hc_tx_packet_sent: does accounting for packets in flight by HC-sender
+ *  @ccid_hc_{r,t}x_get_info: INET_DIAG information for HC-receiver/sender
+ *  @ccid_hc_{r,t}x_getsockopt: socket options specific to HC-receiver/sender
+ */
+struct ccid_operations {
+	unsigned char		ccid_id;
+	__u32			ccid_ccmps;
+	const char		*ccid_name;
+	struct module		*ccid_owner;
+	struct kmem_cache	*ccid_hc_rx_slab,
+				*ccid_hc_tx_slab;
+	__u32			ccid_hc_rx_obj_size,
+				ccid_hc_tx_obj_size;
+	/* Interface Routines */
+	int		(*ccid_hc_rx_init)(struct ccid *ccid, struct sock *sk);
+	int		(*ccid_hc_tx_init)(struct ccid *ccid, struct sock *sk);
+	void		(*ccid_hc_rx_exit)(struct sock *sk);
+	void		(*ccid_hc_tx_exit)(struct sock *sk);
+	void		(*ccid_hc_rx_packet_recv)(struct sock *sk,
+						  struct sk_buff *skb);
+	int		(*ccid_hc_rx_parse_options)(struct sock *sk,
+						    unsigned char option,
+						    unsigned char len, u16 idx,
+						    unsigned char* value);
+	int		(*ccid_hc_rx_insert_options)(struct sock *sk,
+						     struct sk_buff *skb);
+	void		(*ccid_hc_tx_packet_recv)(struct sock *sk,
+						  struct sk_buff *skb);
+	int		(*ccid_hc_tx_parse_options)(struct sock *sk,
+						    unsigned char option,
+						    unsigned char len, u16 idx,
+						    unsigned char* value);
+	int		(*ccid_hc_tx_send_packet)(struct sock *sk,
+						  struct sk_buff *skb);
+	void		(*ccid_hc_tx_packet_sent)(struct sock *sk,
+						  int more, unsigned int len);
+	void		(*ccid_hc_rx_get_info)(struct sock *sk,
+					       struct tcp_info *info);
+	void		(*ccid_hc_tx_get_info)(struct sock *sk,
+					       struct tcp_info *info);
+	int		(*ccid_hc_rx_getsockopt)(struct sock *sk,
+						 const int optname, int len,
+						 u32 __user *optval,
+						 int __user *optlen);
+	int		(*ccid_hc_tx_getsockopt)(struct sock *sk,
+						 const int optname, int len,
+						 u32 __user *optval,
+						 int __user *optlen);
+};
+
+extern int ccid_register(struct ccid_operations *ccid_ops);
+extern int ccid_unregister(struct ccid_operations *ccid_ops);
+
+struct ccid {
+	struct ccid_operations *ccid_ops;
+	char		       ccid_priv[0];
+};
+
+static inline void *ccid_priv(const struct ccid *ccid)
+{
+	return (void *)ccid->ccid_priv;
+}
+
+extern struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx,
+			     gfp_t gfp);
+
+extern struct ccid *ccid_hc_rx_new(unsigned char id, struct sock *sk,
+				   gfp_t gfp);
+extern struct ccid *ccid_hc_tx_new(unsigned char id, struct sock *sk,
+				   gfp_t gfp);
+
+extern void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk);
+extern void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk);
+
+static inline int ccid_hc_tx_send_packet(struct ccid *ccid, struct sock *sk,
+					 struct sk_buff *skb)
+{
+	int rc = 0;
+	if (ccid->ccid_ops->ccid_hc_tx_send_packet != NULL)
+		rc = ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb);
+	return rc;
+}
+
+static inline void ccid_hc_tx_packet_sent(struct ccid *ccid, struct sock *sk,
+					  int more, unsigned int len)
+{
+	if (ccid->ccid_ops->ccid_hc_tx_packet_sent != NULL)
+		ccid->ccid_ops->ccid_hc_tx_packet_sent(sk, more, len);
+}
+
+static inline void ccid_hc_rx_packet_recv(struct ccid *ccid, struct sock *sk,
+					  struct sk_buff *skb)
+{
+	if (ccid->ccid_ops->ccid_hc_rx_packet_recv != NULL)
+		ccid->ccid_ops->ccid_hc_rx_packet_recv(sk, skb);
+}
+
+static inline void ccid_hc_tx_packet_recv(struct ccid *ccid, struct sock *sk,
+					  struct sk_buff *skb)
+{
+	if (ccid->ccid_ops->ccid_hc_tx_packet_recv != NULL)
+		ccid->ccid_ops->ccid_hc_tx_packet_recv(sk, skb);
+}
+
+static inline int ccid_hc_tx_parse_options(struct ccid *ccid, struct sock *sk,
+					   unsigned char option,
+					   unsigned char len, u16 idx,
+					   unsigned char* value)
+{
+	int rc = 0;
+	if (ccid->ccid_ops->ccid_hc_tx_parse_options != NULL)
+		rc = ccid->ccid_ops->ccid_hc_tx_parse_options(sk, option, len, idx,
+						    value);
+	return rc;
+}
+
+static inline int ccid_hc_rx_parse_options(struct ccid *ccid, struct sock *sk,
+					   unsigned char option,
+					   unsigned char len, u16 idx,
+					   unsigned char* value)
+{
+	int rc = 0;
+	if (ccid->ccid_ops->ccid_hc_rx_parse_options != NULL)
+		rc = ccid->ccid_ops->ccid_hc_rx_parse_options(sk, option, len, idx, value);
+	return rc;
+}
+
+static inline int ccid_hc_rx_insert_options(struct ccid *ccid, struct sock *sk,
+					    struct sk_buff *skb)
+{
+	if (ccid->ccid_ops->ccid_hc_rx_insert_options != NULL)
+		return ccid->ccid_ops->ccid_hc_rx_insert_options(sk, skb);
+	return 0;
+}
+
+static inline void ccid_hc_rx_get_info(struct ccid *ccid, struct sock *sk,
+				       struct tcp_info *info)
+{
+	if (ccid->ccid_ops->ccid_hc_rx_get_info != NULL)
+		ccid->ccid_ops->ccid_hc_rx_get_info(sk, info);
+}
+
+static inline void ccid_hc_tx_get_info(struct ccid *ccid, struct sock *sk,
+				       struct tcp_info *info)
+{
+	if (ccid->ccid_ops->ccid_hc_tx_get_info != NULL)
+		ccid->ccid_ops->ccid_hc_tx_get_info(sk, info);
+}
+
+static inline int ccid_hc_rx_getsockopt(struct ccid *ccid, struct sock *sk,
+					const int optname, int len,
+					u32 __user *optval, int __user *optlen)
+{
+	int rc = -ENOPROTOOPT;
+	if (ccid->ccid_ops->ccid_hc_rx_getsockopt != NULL)
+		rc = ccid->ccid_ops->ccid_hc_rx_getsockopt(sk, optname, len,
+						 optval, optlen);
+	return rc;
+}
+
+static inline int ccid_hc_tx_getsockopt(struct ccid *ccid, struct sock *sk,
+					const int optname, int len,
+					u32 __user *optval, int __user *optlen)
+{
+	int rc = -ENOPROTOOPT;
+	if (ccid->ccid_ops->ccid_hc_tx_getsockopt != NULL)
+		rc = ccid->ccid_ops->ccid_hc_tx_getsockopt(sk, optname, len,
+						 optval, optlen);
+	return rc;
+}
+#endif /* _CCID_H */
diff --git a/net/dccp/ccids/Kconfig b/net/dccp/ccids/Kconfig
new file mode 100644
index 0000000..1227594
--- /dev/null
+++ b/net/dccp/ccids/Kconfig
@@ -0,0 +1,119 @@
+menu "DCCP CCIDs Configuration (EXPERIMENTAL)"
+	depends on EXPERIMENTAL
+
+config IP_DCCP_CCID2
+	tristate "CCID2 (TCP-Like) (EXPERIMENTAL)"
+	def_tristate IP_DCCP
+	select IP_DCCP_ACKVEC
+	---help---
+	  CCID 2, TCP-like Congestion Control, denotes Additive Increase,
+	  Multiplicative Decrease (AIMD) congestion control with behavior
+	  modelled directly on TCP, including congestion window, slow start,
+	  timeouts, and so forth [RFC 2581].  CCID 2 achieves maximum
+	  bandwidth over the long term, consistent with the use of end-to-end
+	  congestion control, but halves its congestion window in response to
+	  each congestion event.  This leads to the abrupt rate changes
+	  typical of TCP.  Applications should use CCID 2 if they prefer
+	  maximum bandwidth utilization to steadiness of rate.  This is often
+	  the case for applications that are not playing their data directly
+	  to the user.  For example, a hypothetical application that
+	  transferred files over DCCP, using application-level retransmissions
+	  for lost packets, would prefer CCID 2 to CCID 3.  On-line games may
+	  also prefer CCID 2.  See RFC 4341 for further details.
+
+	  CCID2 is the default CCID used by DCCP.
+
+config IP_DCCP_CCID2_DEBUG
+	  bool "CCID2 debugging messages"
+	  depends on IP_DCCP_CCID2
+	  ---help---
+	    Enable CCID2-specific debugging messages.
+
+	    When compiling CCID2 as a module, this debugging output can
+	    additionally be toggled by setting the ccid2_debug module
+	    parameter to 0 or 1.
+
+	    If in doubt, say N.
+
+config IP_DCCP_CCID3
+	tristate "CCID3 (TCP-Friendly) (EXPERIMENTAL)"
+	def_tristate IP_DCCP
+	select IP_DCCP_TFRC_LIB
+	---help---
+	  CCID 3 denotes TCP-Friendly Rate Control (TFRC), an equation-based
+	  rate-controlled congestion control mechanism.  TFRC is designed to
+	  be reasonably fair when competing for bandwidth with TCP-like flows,
+	  where a flow is "reasonably fair" if its sending rate is generally
+	  within a factor of two of the sending rate of a TCP flow under the
+	  same conditions.  However, TFRC has a much lower variation of
+	  throughput over time compared with TCP, which makes CCID 3 more
+	  suitable than CCID 2 for applications such streaming media where a
+	  relatively smooth sending rate is of importance.
+
+	  CCID 3 is further described in RFC 4342,
+	  http://www.ietf.org/rfc/rfc4342.txt
+
+	  The TFRC congestion control algorithms were initially described in
+	  RFC 3448.
+
+	  This text was extracted from RFC 4340 (sec. 10.2),
+	  http://www.ietf.org/rfc/rfc4340.txt
+	  
+	  To compile this CCID as a module, choose M here: the module will be
+	  called dccp_ccid3.
+
+	  If in doubt, say M.
+
+config IP_DCCP_CCID3_DEBUG
+	  bool "CCID3 debugging messages"
+	  depends on IP_DCCP_CCID3
+	  ---help---
+	    Enable CCID3-specific debugging messages.
+
+	    When compiling CCID3 as a module, this debugging output can
+	    additionally be toggled by setting the ccid3_debug module
+	    parameter to 0 or 1.
+
+	    If in doubt, say N.
+
+config IP_DCCP_CCID3_RTO
+	  int "Use higher bound for nofeedback timer"
+	  default 100
+	  depends on IP_DCCP_CCID3 && EXPERIMENTAL
+	  ---help---
+	    Use higher lower bound for nofeedback timer expiration.
+
+	    The TFRC nofeedback timer normally expires after the maximum of 4
+	    RTTs and twice the current send interval (RFC 3448, 4.3). On LANs
+	    with a small RTT this can mean a high processing load and reduced
+	    performance, since then the nofeedback timer is triggered very
+	    frequently.
+
+	    This option enables to set a higher lower bound for the nofeedback
+	    value. Values in units of milliseconds can be set here.
+
+	    A value of 0 disables this feature by enforcing the value specified
+	    in RFC 3448. The following values have been suggested as bounds for
+	    experimental use:
+	    	* 16-20ms to match the typical multimedia inter-frame interval
+	    	* 100ms as a reasonable compromise [default]
+	    	* 1000ms corresponds to the lower TCP RTO bound (RFC 2988, 2.4)
+
+	    The default of 100ms is a compromise between a large value for
+	    efficient DCCP implementations, and a small value to avoid disrupting
+	    the network in times of congestion.
+
+	    The purpose of the nofeedback timer is to slow DCCP down when there
+	    is serious network congestion: experimenting with larger values should
+	    therefore not be performed on WANs.
+
+config IP_DCCP_TFRC_LIB
+	tristate
+	default n
+
+config IP_DCCP_TFRC_DEBUG
+	bool
+	depends on IP_DCCP_TFRC_LIB
+	default y if IP_DCCP_CCID3_DEBUG
+
+endmenu
diff --git a/net/dccp/ccids/Makefile b/net/dccp/ccids/Makefile
new file mode 100644
index 0000000..438f20b
--- /dev/null
+++ b/net/dccp/ccids/Makefile
@@ -0,0 +1,9 @@
+obj-$(CONFIG_IP_DCCP_CCID3) += dccp_ccid3.o
+
+dccp_ccid3-y := ccid3.o
+
+obj-$(CONFIG_IP_DCCP_CCID2) += dccp_ccid2.o
+
+dccp_ccid2-y := ccid2.o
+
+obj-y += lib/
diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
new file mode 100644
index 0000000..9a43073
--- /dev/null
+++ b/net/dccp/ccids/ccid2.c
@@ -0,0 +1,805 @@
+/*
+ *  net/dccp/ccids/ccid2.c
+ *
+ *  Copyright (c) 2005, 2006 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
+ *
+ *  Changes to meet Linux coding standards, and DCCP infrastructure fixes.
+ *
+ *  Copyright (c) 2006 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+ * This implementation should follow RFC 4341
+ */
+
+#include "../ccid.h"
+#include "../dccp.h"
+#include "ccid2.h"
+
+
+#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
+static int ccid2_debug;
+#define ccid2_pr_debug(format, a...)	DCCP_PR_DEBUG(ccid2_debug, format, ##a)
+
+static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hctx)
+{
+	int len = 0;
+	int pipe = 0;
+	struct ccid2_seq *seqp = hctx->ccid2hctx_seqh;
+
+	/* there is data in the chain */
+	if (seqp != hctx->ccid2hctx_seqt) {
+		seqp = seqp->ccid2s_prev;
+		len++;
+		if (!seqp->ccid2s_acked)
+			pipe++;
+
+		while (seqp != hctx->ccid2hctx_seqt) {
+			struct ccid2_seq *prev = seqp->ccid2s_prev;
+
+			len++;
+			if (!prev->ccid2s_acked)
+				pipe++;
+
+			/* packets are sent sequentially */
+			BUG_ON(dccp_delta_seqno(seqp->ccid2s_seq,
+						prev->ccid2s_seq ) >= 0);
+			BUG_ON(time_before(seqp->ccid2s_sent,
+					   prev->ccid2s_sent));
+
+			seqp = prev;
+		}
+	}
+
+	BUG_ON(pipe != hctx->ccid2hctx_pipe);
+	ccid2_pr_debug("len of chain=%d\n", len);
+
+	do {
+		seqp = seqp->ccid2s_prev;
+		len++;
+	} while (seqp != hctx->ccid2hctx_seqh);
+
+	ccid2_pr_debug("total len=%d\n", len);
+	BUG_ON(len != hctx->ccid2hctx_seqbufc * CCID2_SEQBUF_LEN);
+}
+#else
+#define ccid2_pr_debug(format, a...)
+#define ccid2_hc_tx_check_sanity(hctx)
+#endif
+
+static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hctx)
+{
+	struct ccid2_seq *seqp;
+	int i;
+
+	/* check if we have space to preserve the pointer to the buffer */
+	if (hctx->ccid2hctx_seqbufc >= (sizeof(hctx->ccid2hctx_seqbuf) /
+					sizeof(struct ccid2_seq*)))
+		return -ENOMEM;
+
+	/* allocate buffer and initialize linked list */
+	seqp = kmalloc(CCID2_SEQBUF_LEN * sizeof(struct ccid2_seq), gfp_any());
+	if (seqp == NULL)
+		return -ENOMEM;
+
+	for (i = 0; i < (CCID2_SEQBUF_LEN - 1); i++) {
+		seqp[i].ccid2s_next = &seqp[i + 1];
+		seqp[i + 1].ccid2s_prev = &seqp[i];
+	}
+	seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = seqp;
+	seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
+
+	/* This is the first allocation.  Initiate the head and tail.  */
+	if (hctx->ccid2hctx_seqbufc == 0)
+		hctx->ccid2hctx_seqh = hctx->ccid2hctx_seqt = seqp;
+	else {
+		/* link the existing list with the one we just created */
+		hctx->ccid2hctx_seqh->ccid2s_next = seqp;
+		seqp->ccid2s_prev = hctx->ccid2hctx_seqh;
+
+		hctx->ccid2hctx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
+		seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hctx->ccid2hctx_seqt;
+	}
+
+	/* store the original pointer to the buffer so we can free it */
+	hctx->ccid2hctx_seqbuf[hctx->ccid2hctx_seqbufc] = seqp;
+	hctx->ccid2hctx_seqbufc++;
+
+	return 0;
+}
+
+static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
+{
+	struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+
+	if (hctx->ccid2hctx_pipe < hctx->ccid2hctx_cwnd)
+		return 0;
+
+	return 1; /* XXX CCID should dequeue when ready instead of polling */
+}
+
+static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->ccid2hctx_cwnd, 2);
+
+	/*
+	 * Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from
+	 * RFC 4341, 6.1.2. We ignore the statement that Ack Ratio 2 is always
+	 * acceptable since this causes starvation/deadlock whenever cwnd < 2.
+	 * The same problem arises when Ack Ratio is 0 (ie. Ack Ratio disabled).
+	 */
+	if (val == 0 || val > max_ratio) {
+		DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio);
+		val = max_ratio;
+	}
+	if (val > 0xFFFF)		/* RFC 4340, 11.3 */
+		val = 0xFFFF;
+
+	if (val == dp->dccps_l_ack_ratio)
+		return;
+
+	ccid2_pr_debug("changing local ack ratio to %u\n", val);
+	dp->dccps_l_ack_ratio = val;
+}
+
+static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hctx, long val)
+{
+	ccid2_pr_debug("change SRTT to %ld\n", val);
+	hctx->ccid2hctx_srtt = val;
+}
+
+static void ccid2_start_rto_timer(struct sock *sk);
+
+static void ccid2_hc_tx_rto_expire(unsigned long data)
+{
+	struct sock *sk = (struct sock *)data;
+	struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+	long s;
+
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk)) {
+		sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
+			       jiffies + HZ / 5);
+		goto out;
+	}
+
+	ccid2_pr_debug("RTO_EXPIRE\n");
+
+	ccid2_hc_tx_check_sanity(hctx);
+
+	/* back-off timer */
+	hctx->ccid2hctx_rto <<= 1;
+
+	s = hctx->ccid2hctx_rto / HZ;
+	if (s > 60)
+		hctx->ccid2hctx_rto = 60 * HZ;
+
+	ccid2_start_rto_timer(sk);
+
+	/* adjust pipe, cwnd etc */
+	hctx->ccid2hctx_ssthresh = hctx->ccid2hctx_cwnd / 2;
+	if (hctx->ccid2hctx_ssthresh < 2)
+		hctx->ccid2hctx_ssthresh = 2;
+	hctx->ccid2hctx_cwnd	 = 1;
+	hctx->ccid2hctx_pipe	 = 0;
+
+	/* clear state about stuff we sent */
+	hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqh;
+	hctx->ccid2hctx_packets_acked = 0;
+
+	/* clear ack ratio state. */
+	hctx->ccid2hctx_rpseq	 = 0;
+	hctx->ccid2hctx_rpdupack = -1;
+	ccid2_change_l_ack_ratio(sk, 1);
+	ccid2_hc_tx_check_sanity(hctx);
+out:
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
+
+static void ccid2_start_rto_timer(struct sock *sk)
+{
+	struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+
+	ccid2_pr_debug("setting RTO timeout=%ld\n", hctx->ccid2hctx_rto);
+
+	BUG_ON(timer_pending(&hctx->ccid2hctx_rtotimer));
+	sk_reset_timer(sk, &hctx->ccid2hctx_rtotimer,
+		       jiffies + hctx->ccid2hctx_rto);
+}
+
+static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+	struct ccid2_seq *next;
+
+	hctx->ccid2hctx_pipe++;
+
+	hctx->ccid2hctx_seqh->ccid2s_seq   = dp->dccps_gss;
+	hctx->ccid2hctx_seqh->ccid2s_acked = 0;
+	hctx->ccid2hctx_seqh->ccid2s_sent  = jiffies;
+
+	next = hctx->ccid2hctx_seqh->ccid2s_next;
+	/* check if we need to alloc more space */
+	if (next == hctx->ccid2hctx_seqt) {
+		if (ccid2_hc_tx_alloc_seq(hctx)) {
+			DCCP_CRIT("packet history - out of memory!");
+			/* FIXME: find a more graceful way to bail out */
+			return;
+		}
+		next = hctx->ccid2hctx_seqh->ccid2s_next;
+		BUG_ON(next == hctx->ccid2hctx_seqt);
+	}
+	hctx->ccid2hctx_seqh = next;
+
+	ccid2_pr_debug("cwnd=%d pipe=%d\n", hctx->ccid2hctx_cwnd,
+		       hctx->ccid2hctx_pipe);
+
+	/*
+	 * FIXME: The code below is broken and the variables have been removed
+	 * from the socket struct. The `ackloss' variable was always set to 0,
+	 * and with arsent there are several problems:
+	 *  (i) it doesn't just count the number of Acks, but all sent packets;
+	 *  (ii) it is expressed in # of packets, not # of windows, so the
+	 *  comparison below uses the wrong formula: Appendix A of RFC 4341
+	 *  comes up with the number K = cwnd / (R^2 - R) of consecutive windows
+	 *  of data with no lost or marked Ack packets. If arsent were the # of
+	 *  consecutive Acks received without loss, then Ack Ratio needs to be
+	 *  decreased by 1 when
+	 *	      arsent >=  K * cwnd / R  =  cwnd^2 / (R^3 - R^2)
+	 *  where cwnd / R is the number of Acks received per window of data
+	 *  (cf. RFC 4341, App. A). The problems are that
+	 *  - arsent counts other packets as well;
+	 *  - the comparison uses a formula different from RFC 4341;
+	 *  - computing a cubic/quadratic equation each time is too complicated.
+	 *  Hence a different algorithm is needed.
+	 */
+#if 0
+	/* Ack Ratio.  Need to maintain a concept of how many windows we sent */
+	hctx->ccid2hctx_arsent++;
+	/* We had an ack loss in this window... */
+	if (hctx->ccid2hctx_ackloss) {
+		if (hctx->ccid2hctx_arsent >= hctx->ccid2hctx_cwnd) {
+			hctx->ccid2hctx_arsent	= 0;
+			hctx->ccid2hctx_ackloss	= 0;
+		}
+	} else {
+		/* No acks lost up to now... */
+		/* decrease ack ratio if enough packets were sent */
+		if (dp->dccps_l_ack_ratio > 1) {
+			/* XXX don't calculate denominator each time */
+			int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio -
+				    dp->dccps_l_ack_ratio;
+
+			denom = hctx->ccid2hctx_cwnd * hctx->ccid2hctx_cwnd / denom;
+
+			if (hctx->ccid2hctx_arsent >= denom) {
+				ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
+				hctx->ccid2hctx_arsent = 0;
+			}
+		} else {
+			/* we can't increase ack ratio further [1] */
+			hctx->ccid2hctx_arsent = 0; /* or maybe set it to cwnd*/
+		}
+	}
+#endif
+
+	/* setup RTO timer */
+	if (!timer_pending(&hctx->ccid2hctx_rtotimer))
+		ccid2_start_rto_timer(sk);
+
+#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
+	do {
+		struct ccid2_seq *seqp = hctx->ccid2hctx_seqt;
+
+		while (seqp != hctx->ccid2hctx_seqh) {
+			ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
+				       (unsigned long long)seqp->ccid2s_seq,
+				       seqp->ccid2s_acked, seqp->ccid2s_sent);
+			seqp = seqp->ccid2s_next;
+		}
+	} while (0);
+	ccid2_pr_debug("=========\n");
+	ccid2_hc_tx_check_sanity(hctx);
+#endif
+}
+
+/* XXX Lame code duplication!
+ * returns -1 if none was found.
+ * else returns the next offset to use in the function call.
+ */
+static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
+			   unsigned char **vec, unsigned char *veclen)
+{
+	const struct dccp_hdr *dh = dccp_hdr(skb);
+	unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
+	unsigned char *opt_ptr;
+	const unsigned char *opt_end = (unsigned char *)dh +
+					(dh->dccph_doff * 4);
+	unsigned char opt, len;
+	unsigned char *value;
+
+	BUG_ON(offset < 0);
+	options += offset;
+	opt_ptr = options;
+	if (opt_ptr >= opt_end)
+		return -1;
+
+	while (opt_ptr != opt_end) {
+		opt   = *opt_ptr++;
+		len   = 0;
+		value = NULL;
+
+		/* Check if this isn't a single byte option */
+		if (opt > DCCPO_MAX_RESERVED) {
+			if (opt_ptr == opt_end)
+				goto out_invalid_option;
+
+			len = *opt_ptr++;
+			if (len < 3)
+				goto out_invalid_option;
+			/*
+			 * Remove the type and len fields, leaving
+			 * just the value size
+			 */
+			len     -= 2;
+			value   = opt_ptr;
+			opt_ptr += len;
+
+			if (opt_ptr > opt_end)
+				goto out_invalid_option;
+		}
+
+		switch (opt) {
+		case DCCPO_ACK_VECTOR_0:
+		case DCCPO_ACK_VECTOR_1:
+			*vec	= value;
+			*veclen = len;
+			return offset + (opt_ptr - options);
+		}
+	}
+
+	return -1;
+
+out_invalid_option:
+	DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
+	return -1;
+}
+
+static void ccid2_hc_tx_kill_rto_timer(struct sock *sk)
+{
+	struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+
+	sk_stop_timer(sk, &hctx->ccid2hctx_rtotimer);
+	ccid2_pr_debug("deleted RTO timer\n");
+}
+
+static inline void ccid2_new_ack(struct sock *sk,
+				 struct ccid2_seq *seqp,
+				 unsigned int *maxincr)
+{
+	struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+
+	if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh) {
+		if (*maxincr > 0 && ++hctx->ccid2hctx_packets_acked == 2) {
+			hctx->ccid2hctx_cwnd += 1;
+			*maxincr	     -= 1;
+			hctx->ccid2hctx_packets_acked = 0;
+		}
+	} else if (++hctx->ccid2hctx_packets_acked >= hctx->ccid2hctx_cwnd) {
+			hctx->ccid2hctx_cwnd += 1;
+			hctx->ccid2hctx_packets_acked = 0;
+	}
+
+	/* update RTO */
+	if (hctx->ccid2hctx_srtt == -1 ||
+	    time_after(jiffies, hctx->ccid2hctx_lastrtt + hctx->ccid2hctx_srtt)) {
+		unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent;
+		int s;
+
+		/* first measurement */
+		if (hctx->ccid2hctx_srtt == -1) {
+			ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
+				       r, jiffies,
+				       (unsigned long long)seqp->ccid2s_seq);
+			ccid2_change_srtt(hctx, r);
+			hctx->ccid2hctx_rttvar = r >> 1;
+		} else {
+			/* RTTVAR */
+			long tmp = hctx->ccid2hctx_srtt - r;
+			long srtt;
+
+			if (tmp < 0)
+				tmp *= -1;
+
+			tmp >>= 2;
+			hctx->ccid2hctx_rttvar *= 3;
+			hctx->ccid2hctx_rttvar >>= 2;
+			hctx->ccid2hctx_rttvar += tmp;
+
+			/* SRTT */
+			srtt = hctx->ccid2hctx_srtt;
+			srtt *= 7;
+			srtt >>= 3;
+			tmp = r >> 3;
+			srtt += tmp;
+			ccid2_change_srtt(hctx, srtt);
+		}
+		s = hctx->ccid2hctx_rttvar << 2;
+		/* clock granularity is 1 when based on jiffies */
+		if (!s)
+			s = 1;
+		hctx->ccid2hctx_rto = hctx->ccid2hctx_srtt + s;
+
+		/* must be at least a second */
+		s = hctx->ccid2hctx_rto / HZ;
+		/* DCCP doesn't require this [but I like it cuz my code sux] */
+#if 1
+		if (s < 1)
+			hctx->ccid2hctx_rto = HZ;
+#endif
+		/* max 60 seconds */
+		if (s > 60)
+			hctx->ccid2hctx_rto = HZ * 60;
+
+		hctx->ccid2hctx_lastrtt = jiffies;
+
+		ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
+			       hctx->ccid2hctx_srtt, hctx->ccid2hctx_rttvar,
+			       hctx->ccid2hctx_rto, HZ, r);
+	}
+
+	/* we got a new ack, so re-start RTO timer */
+	ccid2_hc_tx_kill_rto_timer(sk);
+	ccid2_start_rto_timer(sk);
+}
+
+static void ccid2_hc_tx_dec_pipe(struct sock *sk)
+{
+	struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+
+	if (hctx->ccid2hctx_pipe == 0)
+		DCCP_BUG("pipe == 0");
+	else
+		hctx->ccid2hctx_pipe--;
+
+	if (hctx->ccid2hctx_pipe == 0)
+		ccid2_hc_tx_kill_rto_timer(sk);
+}
+
+static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp)
+{
+	struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+
+	if (time_before(seqp->ccid2s_sent, hctx->ccid2hctx_last_cong)) {
+		ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
+		return;
+	}
+
+	hctx->ccid2hctx_last_cong = jiffies;
+
+	hctx->ccid2hctx_cwnd     = hctx->ccid2hctx_cwnd / 2 ? : 1U;
+	hctx->ccid2hctx_ssthresh = max(hctx->ccid2hctx_cwnd, 2U);
+
+	/* Avoid spurious timeouts resulting from Ack Ratio > cwnd */
+	if (dccp_sk(sk)->dccps_l_ack_ratio > hctx->ccid2hctx_cwnd)
+		ccid2_change_l_ack_ratio(sk, hctx->ccid2hctx_cwnd);
+}
+
+static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+	u64 ackno, seqno;
+	struct ccid2_seq *seqp;
+	unsigned char *vector;
+	unsigned char veclen;
+	int offset = 0;
+	int done = 0;
+	unsigned int maxincr = 0;
+
+	ccid2_hc_tx_check_sanity(hctx);
+	/* check reverse path congestion */
+	seqno = DCCP_SKB_CB(skb)->dccpd_seq;
+
+	/* XXX this whole "algorithm" is broken.  Need to fix it to keep track
+	 * of the seqnos of the dupacks so that rpseq and rpdupack are correct
+	 * -sorbo.
+	 */
+	/* need to bootstrap */
+	if (hctx->ccid2hctx_rpdupack == -1) {
+		hctx->ccid2hctx_rpdupack = 0;
+		hctx->ccid2hctx_rpseq = seqno;
+	} else {
+		/* check if packet is consecutive */
+		if (dccp_delta_seqno(hctx->ccid2hctx_rpseq, seqno) == 1)
+			hctx->ccid2hctx_rpseq = seqno;
+		/* it's a later packet */
+		else if (after48(seqno, hctx->ccid2hctx_rpseq)) {
+			hctx->ccid2hctx_rpdupack++;
+
+			/* check if we got enough dupacks */
+			if (hctx->ccid2hctx_rpdupack >= NUMDUPACK) {
+				hctx->ccid2hctx_rpdupack = -1; /* XXX lame */
+				hctx->ccid2hctx_rpseq = 0;
+
+				ccid2_change_l_ack_ratio(sk, 2 * dp->dccps_l_ack_ratio);
+			}
+		}
+	}
+
+	/* check forward path congestion */
+	/* still didn't send out new data packets */
+	if (hctx->ccid2hctx_seqh == hctx->ccid2hctx_seqt)
+		return;
+
+	switch (DCCP_SKB_CB(skb)->dccpd_type) {
+	case DCCP_PKT_ACK:
+	case DCCP_PKT_DATAACK:
+		break;
+	default:
+		return;
+	}
+
+	ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
+	if (after48(ackno, hctx->ccid2hctx_high_ack))
+		hctx->ccid2hctx_high_ack = ackno;
+
+	seqp = hctx->ccid2hctx_seqt;
+	while (before48(seqp->ccid2s_seq, ackno)) {
+		seqp = seqp->ccid2s_next;
+		if (seqp == hctx->ccid2hctx_seqh) {
+			seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
+			break;
+		}
+	}
+
+	/*
+	 * In slow-start, cwnd can increase up to a maximum of Ack Ratio/2
+	 * packets per acknowledgement. Rounding up avoids that cwnd is not
+	 * advanced when Ack Ratio is 1 and gives a slight edge otherwise.
+	 */
+	if (hctx->ccid2hctx_cwnd < hctx->ccid2hctx_ssthresh)
+		maxincr = DIV_ROUND_UP(dp->dccps_l_ack_ratio, 2);
+
+	/* go through all ack vectors */
+	while ((offset = ccid2_ackvector(sk, skb, offset,
+					 &vector, &veclen)) != -1) {
+		/* go through this ack vector */
+		while (veclen--) {
+			const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK;
+			u64 ackno_end_rl = SUB48(ackno, rl);
+
+			ccid2_pr_debug("ackvec start:%llu end:%llu\n",
+				       (unsigned long long)ackno,
+				       (unsigned long long)ackno_end_rl);
+			/* if the seqno we are analyzing is larger than the
+			 * current ackno, then move towards the tail of our
+			 * seqnos.
+			 */
+			while (after48(seqp->ccid2s_seq, ackno)) {
+				if (seqp == hctx->ccid2hctx_seqt) {
+					done = 1;
+					break;
+				}
+				seqp = seqp->ccid2s_prev;
+			}
+			if (done)
+				break;
+
+			/* check all seqnos in the range of the vector
+			 * run length
+			 */
+			while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
+				const u8 state = *vector &
+						 DCCP_ACKVEC_STATE_MASK;
+
+				/* new packet received or marked */
+				if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED &&
+				    !seqp->ccid2s_acked) {
+					if (state ==
+					    DCCP_ACKVEC_STATE_ECN_MARKED) {
+						ccid2_congestion_event(sk,
+								       seqp);
+					} else
+						ccid2_new_ack(sk, seqp,
+							      &maxincr);
+
+					seqp->ccid2s_acked = 1;
+					ccid2_pr_debug("Got ack for %llu\n",
+						       (unsigned long long)seqp->ccid2s_seq);
+					ccid2_hc_tx_dec_pipe(sk);
+				}
+				if (seqp == hctx->ccid2hctx_seqt) {
+					done = 1;
+					break;
+				}
+				seqp = seqp->ccid2s_prev;
+			}
+			if (done)
+				break;
+
+			ackno = SUB48(ackno_end_rl, 1);
+			vector++;
+		}
+		if (done)
+			break;
+	}
+
+	/* The state about what is acked should be correct now
+	 * Check for NUMDUPACK
+	 */
+	seqp = hctx->ccid2hctx_seqt;
+	while (before48(seqp->ccid2s_seq, hctx->ccid2hctx_high_ack)) {
+		seqp = seqp->ccid2s_next;
+		if (seqp == hctx->ccid2hctx_seqh) {
+			seqp = hctx->ccid2hctx_seqh->ccid2s_prev;
+			break;
+		}
+	}
+	done = 0;
+	while (1) {
+		if (seqp->ccid2s_acked) {
+			done++;
+			if (done == NUMDUPACK)
+				break;
+		}
+		if (seqp == hctx->ccid2hctx_seqt)
+			break;
+		seqp = seqp->ccid2s_prev;
+	}
+
+	/* If there are at least 3 acknowledgements, anything unacknowledged
+	 * below the last sequence number is considered lost
+	 */
+	if (done == NUMDUPACK) {
+		struct ccid2_seq *last_acked = seqp;
+
+		/* check for lost packets */
+		while (1) {
+			if (!seqp->ccid2s_acked) {
+				ccid2_pr_debug("Packet lost: %llu\n",
+					       (unsigned long long)seqp->ccid2s_seq);
+				/* XXX need to traverse from tail -> head in
+				 * order to detect multiple congestion events in
+				 * one ack vector.
+				 */
+				ccid2_congestion_event(sk, seqp);
+				ccid2_hc_tx_dec_pipe(sk);
+			}
+			if (seqp == hctx->ccid2hctx_seqt)
+				break;
+			seqp = seqp->ccid2s_prev;
+		}
+
+		hctx->ccid2hctx_seqt = last_acked;
+	}
+
+	/* trim acked packets in tail */
+	while (hctx->ccid2hctx_seqt != hctx->ccid2hctx_seqh) {
+		if (!hctx->ccid2hctx_seqt->ccid2s_acked)
+			break;
+
+		hctx->ccid2hctx_seqt = hctx->ccid2hctx_seqt->ccid2s_next;
+	}
+
+	ccid2_hc_tx_check_sanity(hctx);
+}
+
+static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
+{
+	struct ccid2_hc_tx_sock *hctx = ccid_priv(ccid);
+	struct dccp_sock *dp = dccp_sk(sk);
+	u32 max_ratio;
+
+	/* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */
+	hctx->ccid2hctx_ssthresh  = ~0U;
+
+	/*
+	 * RFC 4341, 5: "The cwnd parameter is initialized to at most four
+	 * packets for new connections, following the rules from [RFC3390]".
+	 * We need to convert the bytes of RFC3390 into the packets of RFC 4341.
+	 */
+	hctx->ccid2hctx_cwnd = clamp(4380U / dp->dccps_mss_cache, 2U, 4U);
+
+	/* Make sure that Ack Ratio is enabled and within bounds. */
+	max_ratio = DIV_ROUND_UP(hctx->ccid2hctx_cwnd, 2);
+	if (dp->dccps_l_ack_ratio == 0 || dp->dccps_l_ack_ratio > max_ratio)
+		dp->dccps_l_ack_ratio = max_ratio;
+
+	/* XXX init ~ to window size... */
+	if (ccid2_hc_tx_alloc_seq(hctx))
+		return -ENOMEM;
+
+	hctx->ccid2hctx_rto	 = 3 * HZ;
+	ccid2_change_srtt(hctx, -1);
+	hctx->ccid2hctx_rttvar	 = -1;
+	hctx->ccid2hctx_rpdupack = -1;
+	hctx->ccid2hctx_last_cong = jiffies;
+	setup_timer(&hctx->ccid2hctx_rtotimer, ccid2_hc_tx_rto_expire,
+			(unsigned long)sk);
+
+	ccid2_hc_tx_check_sanity(hctx);
+	return 0;
+}
+
+static void ccid2_hc_tx_exit(struct sock *sk)
+{
+	struct ccid2_hc_tx_sock *hctx = ccid2_hc_tx_sk(sk);
+	int i;
+
+	ccid2_hc_tx_kill_rto_timer(sk);
+
+	for (i = 0; i < hctx->ccid2hctx_seqbufc; i++)
+		kfree(hctx->ccid2hctx_seqbuf[i]);
+	hctx->ccid2hctx_seqbufc = 0;
+}
+
+static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
+{
+	const struct dccp_sock *dp = dccp_sk(sk);
+	struct ccid2_hc_rx_sock *hcrx = ccid2_hc_rx_sk(sk);
+
+	switch (DCCP_SKB_CB(skb)->dccpd_type) {
+	case DCCP_PKT_DATA:
+	case DCCP_PKT_DATAACK:
+		hcrx->ccid2hcrx_data++;
+		if (hcrx->ccid2hcrx_data >= dp->dccps_r_ack_ratio) {
+			dccp_send_ack(sk);
+			hcrx->ccid2hcrx_data = 0;
+		}
+		break;
+	}
+}
+
+static struct ccid_operations ccid2 = {
+	.ccid_id		= DCCPC_CCID2,
+	.ccid_name		= "TCP-like",
+	.ccid_owner		= THIS_MODULE,
+	.ccid_hc_tx_obj_size	= sizeof(struct ccid2_hc_tx_sock),
+	.ccid_hc_tx_init	= ccid2_hc_tx_init,
+	.ccid_hc_tx_exit	= ccid2_hc_tx_exit,
+	.ccid_hc_tx_send_packet	= ccid2_hc_tx_send_packet,
+	.ccid_hc_tx_packet_sent	= ccid2_hc_tx_packet_sent,
+	.ccid_hc_tx_packet_recv	= ccid2_hc_tx_packet_recv,
+	.ccid_hc_rx_obj_size	= sizeof(struct ccid2_hc_rx_sock),
+	.ccid_hc_rx_packet_recv	= ccid2_hc_rx_packet_recv,
+};
+
+#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
+module_param(ccid2_debug, bool, 0644);
+MODULE_PARM_DESC(ccid2_debug, "Enable debug messages");
+#endif
+
+static __init int ccid2_module_init(void)
+{
+	return ccid_register(&ccid2);
+}
+module_init(ccid2_module_init);
+
+static __exit void ccid2_module_exit(void)
+{
+	ccid_unregister(&ccid2);
+}
+module_exit(ccid2_module_exit);
+
+MODULE_AUTHOR("Andrea Bittau <a.bittau@cs.ucl.ac.uk>");
+MODULE_DESCRIPTION("DCCP TCP-Like (CCID2) CCID");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("net-dccp-ccid-2");
diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h
new file mode 100644
index 0000000..2c94ca0
--- /dev/null
+++ b/net/dccp/ccids/ccid2.h
@@ -0,0 +1,84 @@
+/*
+ *  net/dccp/ccids/ccid2.h
+ *
+ *  Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#ifndef _DCCP_CCID2_H_
+#define _DCCP_CCID2_H_
+
+#include <linux/dccp.h>
+#include <linux/timer.h>
+#include <linux/types.h>
+#include "../ccid.h"
+/* NUMDUPACK parameter from RFC 4341, p. 6 */
+#define NUMDUPACK	3
+
+struct sock;
+
+struct ccid2_seq {
+	u64			ccid2s_seq;
+	unsigned long		ccid2s_sent;
+	int			ccid2s_acked;
+	struct ccid2_seq	*ccid2s_prev;
+	struct ccid2_seq	*ccid2s_next;
+};
+
+#define CCID2_SEQBUF_LEN 1024
+#define CCID2_SEQBUF_MAX 128
+
+/** struct ccid2_hc_tx_sock - CCID2 TX half connection
+ *
+ * @ccid2hctx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
+ * @ccid2hctx_packets_acked - Ack counter for deriving cwnd growth (RFC 3465)
+ * @ccid2hctx_lastrtt -time RTT was last measured
+ * @ccid2hctx_rpseq - last consecutive seqno
+ * @ccid2hctx_rpdupack - dupacks since rpseq
+*/
+struct ccid2_hc_tx_sock {
+	u32			ccid2hctx_cwnd;
+	u32			ccid2hctx_ssthresh;
+	u32			ccid2hctx_pipe;
+	u32			ccid2hctx_packets_acked;
+	struct ccid2_seq	*ccid2hctx_seqbuf[CCID2_SEQBUF_MAX];
+	int			ccid2hctx_seqbufc;
+	struct ccid2_seq	*ccid2hctx_seqh;
+	struct ccid2_seq	*ccid2hctx_seqt;
+	long			ccid2hctx_rto;
+	long			ccid2hctx_srtt;
+	long			ccid2hctx_rttvar;
+	unsigned long		ccid2hctx_lastrtt;
+	struct timer_list	ccid2hctx_rtotimer;
+	u64			ccid2hctx_rpseq;
+	int			ccid2hctx_rpdupack;
+	unsigned long		ccid2hctx_last_cong;
+	u64			ccid2hctx_high_ack;
+};
+
+struct ccid2_hc_rx_sock {
+	int	ccid2hcrx_data;
+};
+
+static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
+{
+	return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
+}
+
+static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
+{
+	return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
+}
+#endif /* _DCCP_CCID2_H_ */
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
new file mode 100644
index 0000000..3b8bd7c
--- /dev/null
+++ b/net/dccp/ccids/ccid3.c
@@ -0,0 +1,986 @@
+/*
+ *  net/dccp/ccids/ccid3.c
+ *
+ *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
+ *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
+ *  Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
+ *
+ *  An implementation of the DCCP protocol
+ *
+ *  This code has been developed by the University of Waikato WAND
+ *  research group. For further information please see http://www.wand.net.nz/
+ *
+ *  This code also uses code from Lulea University, rereleased as GPL by its
+ *  authors:
+ *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
+ *
+ *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
+ *  and to make it work as a loadable module in the DCCP stack written by
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
+ *
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include "../dccp.h"
+#include "ccid3.h"
+
+#include <asm/unaligned.h>
+
+#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
+static int ccid3_debug;
+#define ccid3_pr_debug(format, a...)	DCCP_PR_DEBUG(ccid3_debug, format, ##a)
+#else
+#define ccid3_pr_debug(format, a...)
+#endif
+
+/*
+ *	Transmitter Half-Connection Routines
+ */
+#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
+static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
+{
+	static char *ccid3_state_names[] = {
+	[TFRC_SSTATE_NO_SENT]  = "NO_SENT",
+	[TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
+	[TFRC_SSTATE_FBACK]    = "FBACK",
+	[TFRC_SSTATE_TERM]     = "TERM",
+	};
+
+	return ccid3_state_names[state];
+}
+#endif
+
+static void ccid3_hc_tx_set_state(struct sock *sk,
+				  enum ccid3_hc_tx_states state)
+{
+	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
+	enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state;
+
+	ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
+		       dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
+		       ccid3_tx_state_name(state));
+	WARN_ON(state == oldstate);
+	hctx->ccid3hctx_state = state;
+}
+
+/*
+ * Compute the initial sending rate X_init in the manner of RFC 3390:
+ *
+ *	X_init  =  min(4 * s, max(2 * s, 4380 bytes)) / RTT
+ *
+ * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis
+ * (rev-02) clarifies the use of RFC 3390 with regard to the above formula.
+ * For consistency with other parts of the code, X_init is scaled by 2^6.
+ */
+static inline u64 rfc3390_initial_rate(struct sock *sk)
+{
+	const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
+	const __u32 w_init = clamp_t(__u32, 4380U,
+			2 * hctx->ccid3hctx_s, 4 * hctx->ccid3hctx_s);
+
+	return scaled_div(w_init << 6, hctx->ccid3hctx_rtt);
+}
+
+/*
+ * Recalculate t_ipi and delta (should be called whenever X changes)
+ */
+static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx)
+{
+	/* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
+	hctx->ccid3hctx_t_ipi = scaled_div32(((u64)hctx->ccid3hctx_s) << 6,
+					     hctx->ccid3hctx_x);
+
+	/* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
+	hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
+					   TFRC_OPSYS_HALF_TIME_GRAN);
+
+	ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%u\n",
+		       hctx->ccid3hctx_t_ipi, hctx->ccid3hctx_delta,
+		       hctx->ccid3hctx_s, (unsigned)(hctx->ccid3hctx_x >> 6));
+
+}
+
+static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hctx, ktime_t now)
+{
+	u32 delta = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count);
+
+	return delta / hctx->ccid3hctx_rtt;
+}
+
+/**
+ * ccid3_hc_tx_update_x  -  Update allowed sending rate X
+ * @stamp: most recent time if available - can be left NULL.
+ * This function tracks draft rfc3448bis, check there for latest details.
+ *
+ * Note: X and X_recv are both stored in units of 64 * bytes/second, to support
+ *       fine-grained resolution of sending rates. This requires scaling by 2^6
+ *       throughout the code. Only X_calc is unscaled (in bytes/second).
+ *
+ */
+static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp)
+{
+	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
+	__u64 min_rate = 2 * hctx->ccid3hctx_x_recv;
+	const  __u64 old_x = hctx->ccid3hctx_x;
+	ktime_t now = stamp ? *stamp : ktime_get_real();
+
+	/*
+	 * Handle IDLE periods: do not reduce below RFC3390 initial sending rate
+	 * when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis:
+	 * a sender is idle if it has not sent anything over a 2-RTT-period.
+	 * For consistency with X and X_recv, min_rate is also scaled by 2^6.
+	 */
+	if (ccid3_hc_tx_idle_rtt(hctx, now) >= 2) {
+		min_rate = rfc3390_initial_rate(sk);
+		min_rate = max(min_rate, 2 * hctx->ccid3hctx_x_recv);
+	}
+
+	if (hctx->ccid3hctx_p > 0) {
+
+		hctx->ccid3hctx_x = min(((__u64)hctx->ccid3hctx_x_calc) << 6,
+					min_rate);
+		hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
+					(((__u64)hctx->ccid3hctx_s) << 6) /
+								TFRC_T_MBI);
+
+	} else if (ktime_us_delta(now, hctx->ccid3hctx_t_ld)
+				- (s64)hctx->ccid3hctx_rtt >= 0) {
+
+		hctx->ccid3hctx_x = min(2 * hctx->ccid3hctx_x, min_rate);
+		hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
+			    scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
+				       hctx->ccid3hctx_rtt));
+		hctx->ccid3hctx_t_ld = now;
+	}
+
+	if (hctx->ccid3hctx_x != old_x) {
+		ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, "
+			       "X_recv=%u\n", (unsigned)(old_x >> 6),
+			       (unsigned)(hctx->ccid3hctx_x >> 6),
+			       hctx->ccid3hctx_x_calc,
+			       (unsigned)(hctx->ccid3hctx_x_recv >> 6));
+
+		ccid3_update_send_interval(hctx);
+	}
+}
+
+/*
+ *	Track the mean packet size `s' (cf. RFC 4342, 5.3 and  RFC 3448, 4.1)
+ *	@len: DCCP packet payload size in bytes
+ */
+static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
+{
+	const u16 old_s = hctx->ccid3hctx_s;
+
+	hctx->ccid3hctx_s = tfrc_ewma(hctx->ccid3hctx_s, len, 9);
+
+	if (hctx->ccid3hctx_s != old_s)
+		ccid3_update_send_interval(hctx);
+}
+
+/*
+ *	Update Window Counter using the algorithm from [RFC 4342, 8.1].
+ *	As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt().
+ */
+static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
+						ktime_t now)
+{
+	u32 delta = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count),
+	    quarter_rtts = (4 * delta) / hctx->ccid3hctx_rtt;
+
+	if (quarter_rtts > 0) {
+		hctx->ccid3hctx_t_last_win_count = now;
+		hctx->ccid3hctx_last_win_count  += min(quarter_rtts, 5U);
+		hctx->ccid3hctx_last_win_count	&= 0xF;		/* mod 16 */
+	}
+}
+
+static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
+{
+	struct sock *sk = (struct sock *)data;
+	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
+	unsigned long t_nfb = USEC_PER_SEC / 5;
+
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk)) {
+		/* Try again later. */
+		/* XXX: set some sensible MIB */
+		goto restart_timer;
+	}
+
+	ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk,
+		       ccid3_tx_state_name(hctx->ccid3hctx_state));
+
+	if (hctx->ccid3hctx_state == TFRC_SSTATE_FBACK)
+		ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
+	else if (hctx->ccid3hctx_state != TFRC_SSTATE_NO_FBACK)
+		goto out;
+
+	/*
+	 * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4
+	 */
+	if (hctx->ccid3hctx_t_rto == 0 ||	/* no feedback received yet */
+	    hctx->ccid3hctx_p == 0) {
+
+		/* halve send rate directly */
+		hctx->ccid3hctx_x = max(hctx->ccid3hctx_x / 2,
+					(((__u64)hctx->ccid3hctx_s) << 6) /
+								    TFRC_T_MBI);
+		ccid3_update_send_interval(hctx);
+	} else {
+		/*
+		 *  Modify the cached value of X_recv
+		 *
+		 *  If (X_calc > 2 * X_recv)
+		 *    X_recv = max(X_recv / 2, s / (2 * t_mbi));
+		 *  Else
+		 *    X_recv = X_calc / 4;
+		 *
+		 *  Note that X_recv is scaled by 2^6 while X_calc is not
+		 */
+		BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
+
+		if (hctx->ccid3hctx_x_calc > (hctx->ccid3hctx_x_recv >> 5))
+			hctx->ccid3hctx_x_recv =
+				max(hctx->ccid3hctx_x_recv / 2,
+				    (((__u64)hctx->ccid3hctx_s) << 6) /
+							      (2 * TFRC_T_MBI));
+		else {
+			hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc;
+			hctx->ccid3hctx_x_recv <<= 4;
+		}
+		ccid3_hc_tx_update_x(sk, NULL);
+	}
+	ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n",
+			(unsigned long long)hctx->ccid3hctx_x);
+
+	/*
+	 * Set new timeout for the nofeedback timer.
+	 * See comments in packet_recv() regarding the value of t_RTO.
+	 */
+	if (unlikely(hctx->ccid3hctx_t_rto == 0))	/* no feedback yet */
+		t_nfb = TFRC_INITIAL_TIMEOUT;
+	else
+		t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
+
+restart_timer:
+	sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
+			   jiffies + usecs_to_jiffies(t_nfb));
+out:
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
+
+/*
+ * returns
+ *   > 0: delay (in msecs) that should pass before actually sending
+ *   = 0: can send immediately
+ *   < 0: error condition; do not send packet
+ */
+static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
+	ktime_t now = ktime_get_real();
+	s64 delay;
+
+	/*
+	 * This function is called only for Data and DataAck packets. Sending
+	 * zero-sized Data(Ack)s is theoretically possible, but for congestion
+	 * control this case is pathological - ignore it.
+	 */
+	if (unlikely(skb->len == 0))
+		return -EBADMSG;
+
+	switch (hctx->ccid3hctx_state) {
+	case TFRC_SSTATE_NO_SENT:
+		sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
+			       (jiffies +
+				usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
+		hctx->ccid3hctx_last_win_count	 = 0;
+		hctx->ccid3hctx_t_last_win_count = now;
+
+		/* Set t_0 for initial packet */
+		hctx->ccid3hctx_t_nom = now;
+
+		hctx->ccid3hctx_s = skb->len;
+
+		/*
+		 * Use initial RTT sample when available: recommended by erratum
+		 * to RFC 4342. This implements the initialisation procedure of
+		 * draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6.
+		 */
+		if (dp->dccps_syn_rtt) {
+			ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt);
+			hctx->ccid3hctx_rtt  = dp->dccps_syn_rtt;
+			hctx->ccid3hctx_x    = rfc3390_initial_rate(sk);
+			hctx->ccid3hctx_t_ld = now;
+		} else {
+			/*
+			 * Sender does not have RTT sample:
+			 * - set fallback RTT (RFC 4340, 3.4) since a RTT value
+			 *   is needed in several parts (e.g.  window counter);
+			 * - set sending rate X_pps = 1pps as per RFC 3448, 4.2.
+			 */
+			hctx->ccid3hctx_rtt = DCCP_FALLBACK_RTT;
+			hctx->ccid3hctx_x   = hctx->ccid3hctx_s;
+			hctx->ccid3hctx_x <<= 6;
+		}
+		ccid3_update_send_interval(hctx);
+
+		ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
+		break;
+	case TFRC_SSTATE_NO_FBACK:
+	case TFRC_SSTATE_FBACK:
+		delay = ktime_us_delta(hctx->ccid3hctx_t_nom, now);
+		ccid3_pr_debug("delay=%ld\n", (long)delay);
+		/*
+		 *	Scheduling of packet transmissions [RFC 3448, 4.6]
+		 *
+		 * if (t_now > t_nom - delta)
+		 *       // send the packet now
+		 * else
+		 *       // send the packet in (t_nom - t_now) milliseconds.
+		 */
+		if (delay - (s64)hctx->ccid3hctx_delta >= 1000)
+			return (u32)delay / 1000L;
+
+		ccid3_hc_tx_update_win_count(hctx, now);
+		break;
+	case TFRC_SSTATE_TERM:
+		DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
+		return -EINVAL;
+	}
+
+	/* prepare to send now (add options etc.) */
+	dp->dccps_hc_tx_insert_options = 1;
+	DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
+
+	/* set the nominal send time for the next following packet */
+	hctx->ccid3hctx_t_nom = ktime_add_us(hctx->ccid3hctx_t_nom,
+					     hctx->ccid3hctx_t_ipi);
+	return 0;
+}
+
+static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
+				    unsigned int len)
+{
+	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
+
+	ccid3_hc_tx_update_s(hctx, len);
+
+	if (tfrc_tx_hist_add(&hctx->ccid3hctx_hist, dccp_sk(sk)->dccps_gss))
+		DCCP_CRIT("packet history - out of memory!");
+}
+
+static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
+{
+	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
+	struct ccid3_options_received *opt_recv;
+	ktime_t now;
+	unsigned long t_nfb;
+	u32 pinv, r_sample;
+
+	/* we are only interested in ACKs */
+	if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
+	      DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
+		return;
+	/* ... and only in the established state */
+	if (hctx->ccid3hctx_state != TFRC_SSTATE_FBACK &&
+	    hctx->ccid3hctx_state != TFRC_SSTATE_NO_FBACK)
+		return;
+
+	opt_recv = &hctx->ccid3hctx_options_received;
+	now = ktime_get_real();
+
+	/* Estimate RTT from history if ACK number is valid */
+	r_sample = tfrc_tx_hist_rtt(hctx->ccid3hctx_hist,
+				    DCCP_SKB_CB(skb)->dccpd_ack_seq, now);
+	if (r_sample == 0) {
+		DCCP_WARN("%s(%p): %s with bogus ACK-%llu\n", dccp_role(sk), sk,
+			  dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type),
+			  (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq);
+		return;
+	}
+
+	/* Update receive rate in units of 64 * bytes/second */
+	hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
+	hctx->ccid3hctx_x_recv <<= 6;
+
+	/* Update loss event rate (which is scaled by 1e6) */
+	pinv = opt_recv->ccid3or_loss_event_rate;
+	if (pinv == ~0U || pinv == 0)	       /* see RFC 4342, 8.5   */
+		hctx->ccid3hctx_p = 0;
+	else				       /* can not exceed 100% */
+		hctx->ccid3hctx_p = scaled_div(1, pinv);
+	/*
+	 * Validate new RTT sample and update moving average
+	 */
+	r_sample = dccp_sample_rtt(sk, r_sample);
+	hctx->ccid3hctx_rtt = tfrc_ewma(hctx->ccid3hctx_rtt, r_sample, 9);
+	/*
+	 * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
+	 */
+	if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
+		ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
+
+		if (hctx->ccid3hctx_t_rto == 0) {
+			/*
+			 * Initial feedback packet: Larger Initial Windows (4.2)
+			 */
+			hctx->ccid3hctx_x    = rfc3390_initial_rate(sk);
+			hctx->ccid3hctx_t_ld = now;
+
+			ccid3_update_send_interval(hctx);
+
+			goto done_computing_x;
+		} else if (hctx->ccid3hctx_p == 0) {
+			/*
+			 * First feedback after nofeedback timer expiry (4.3)
+			 */
+			goto done_computing_x;
+		}
+	}
+
+	/* Update sending rate (step 4 of [RFC 3448, 4.3]) */
+	if (hctx->ccid3hctx_p > 0)
+		hctx->ccid3hctx_x_calc =
+				tfrc_calc_x(hctx->ccid3hctx_s,
+					    hctx->ccid3hctx_rtt,
+					    hctx->ccid3hctx_p);
+	ccid3_hc_tx_update_x(sk, &now);
+
+done_computing_x:
+	ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
+			       "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
+			       dccp_role(sk),
+			       sk, hctx->ccid3hctx_rtt, r_sample,
+			       hctx->ccid3hctx_s, hctx->ccid3hctx_p,
+			       hctx->ccid3hctx_x_calc,
+			       (unsigned)(hctx->ccid3hctx_x_recv >> 6),
+			       (unsigned)(hctx->ccid3hctx_x >> 6));
+
+	/* unschedule no feedback timer */
+	sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
+
+	/*
+	 * As we have calculated new ipi, delta, t_nom it is possible
+	 * that we now can send a packet, so wake up dccp_wait_for_ccid
+	 */
+	sk->sk_write_space(sk);
+
+	/*
+	 * Update timeout interval for the nofeedback timer.
+	 * We use a configuration option to increase the lower bound.
+	 * This can help avoid triggering the nofeedback timer too
+	 * often ('spinning') on LANs with small RTTs.
+	 */
+	hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
+					   (CONFIG_IP_DCCP_CCID3_RTO *
+					    (USEC_PER_SEC / 1000)));
+	/*
+	 * Schedule no feedback timer to expire in
+	 * max(t_RTO, 2 * s/X)  =  max(t_RTO, 2 * t_ipi)
+	 */
+	t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
+
+	ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
+		       "expire in %lu jiffies (%luus)\n",
+		       dccp_role(sk),
+		       sk, usecs_to_jiffies(t_nfb), t_nfb);
+
+	sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
+			   jiffies + usecs_to_jiffies(t_nfb));
+}
+
+static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
+				     unsigned char len, u16 idx,
+				     unsigned char *value)
+{
+	int rc = 0;
+	const struct dccp_sock *dp = dccp_sk(sk);
+	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
+	struct ccid3_options_received *opt_recv;
+	__be32 opt_val;
+
+	opt_recv = &hctx->ccid3hctx_options_received;
+
+	if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
+		opt_recv->ccid3or_seqno		     = dp->dccps_gsr;
+		opt_recv->ccid3or_loss_event_rate    = ~0;
+		opt_recv->ccid3or_loss_intervals_idx = 0;
+		opt_recv->ccid3or_loss_intervals_len = 0;
+		opt_recv->ccid3or_receive_rate	     = 0;
+	}
+
+	switch (option) {
+	case TFRC_OPT_LOSS_EVENT_RATE:
+		if (unlikely(len != 4)) {
+			DCCP_WARN("%s(%p), invalid len %d "
+				  "for TFRC_OPT_LOSS_EVENT_RATE\n",
+				  dccp_role(sk), sk, len);
+			rc = -EINVAL;
+		} else {
+			opt_val = get_unaligned((__be32 *)value);
+			opt_recv->ccid3or_loss_event_rate = ntohl(opt_val);
+			ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
+				       dccp_role(sk), sk,
+				       opt_recv->ccid3or_loss_event_rate);
+		}
+		break;
+	case TFRC_OPT_LOSS_INTERVALS:
+		opt_recv->ccid3or_loss_intervals_idx = idx;
+		opt_recv->ccid3or_loss_intervals_len = len;
+		ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n",
+			       dccp_role(sk), sk,
+			       opt_recv->ccid3or_loss_intervals_idx,
+			       opt_recv->ccid3or_loss_intervals_len);
+		break;
+	case TFRC_OPT_RECEIVE_RATE:
+		if (unlikely(len != 4)) {
+			DCCP_WARN("%s(%p), invalid len %d "
+				  "for TFRC_OPT_RECEIVE_RATE\n",
+				  dccp_role(sk), sk, len);
+			rc = -EINVAL;
+		} else {
+			opt_val = get_unaligned((__be32 *)value);
+			opt_recv->ccid3or_receive_rate = ntohl(opt_val);
+			ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
+				       dccp_role(sk), sk,
+				       opt_recv->ccid3or_receive_rate);
+		}
+		break;
+	}
+
+	return rc;
+}
+
+static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
+{
+	struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
+
+	hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
+	hctx->ccid3hctx_hist = NULL;
+	setup_timer(&hctx->ccid3hctx_no_feedback_timer,
+			ccid3_hc_tx_no_feedback_timer, (unsigned long)sk);
+
+	return 0;
+}
+
+static void ccid3_hc_tx_exit(struct sock *sk)
+{
+	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
+
+	ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
+	sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
+
+	tfrc_tx_hist_purge(&hctx->ccid3hctx_hist);
+}
+
+static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
+{
+	struct ccid3_hc_tx_sock *hctx;
+
+	/* Listen socks doesn't have a private CCID block */
+	if (sk->sk_state == DCCP_LISTEN)
+		return;
+
+	hctx = ccid3_hc_tx_sk(sk);
+	info->tcpi_rto = hctx->ccid3hctx_t_rto;
+	info->tcpi_rtt = hctx->ccid3hctx_rtt;
+}
+
+static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
+				  u32 __user *optval, int __user *optlen)
+{
+	const struct ccid3_hc_tx_sock *hctx;
+	const void *val;
+
+	/* Listen socks doesn't have a private CCID block */
+	if (sk->sk_state == DCCP_LISTEN)
+		return -EINVAL;
+
+	hctx = ccid3_hc_tx_sk(sk);
+	switch (optname) {
+	case DCCP_SOCKOPT_CCID_TX_INFO:
+		if (len < sizeof(hctx->ccid3hctx_tfrc))
+			return -EINVAL;
+		len = sizeof(hctx->ccid3hctx_tfrc);
+		val = &hctx->ccid3hctx_tfrc;
+		break;
+	default:
+		return -ENOPROTOOPT;
+	}
+
+	if (put_user(len, optlen) || copy_to_user(optval, val, len))
+		return -EFAULT;
+
+	return 0;
+}
+
+/*
+ *	Receiver Half-Connection Routines
+ */
+
+/* CCID3 feedback types */
+enum ccid3_fback_type {
+	CCID3_FBACK_NONE = 0,
+	CCID3_FBACK_INITIAL,
+	CCID3_FBACK_PERIODIC,
+	CCID3_FBACK_PARAM_CHANGE
+};
+
+#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
+static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
+{
+	static char *ccid3_rx_state_names[] = {
+	[TFRC_RSTATE_NO_DATA] = "NO_DATA",
+	[TFRC_RSTATE_DATA]    = "DATA",
+	[TFRC_RSTATE_TERM]    = "TERM",
+	};
+
+	return ccid3_rx_state_names[state];
+}
+#endif
+
+static void ccid3_hc_rx_set_state(struct sock *sk,
+				  enum ccid3_hc_rx_states state)
+{
+	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
+	enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
+
+	ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
+		       dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
+		       ccid3_rx_state_name(state));
+	WARN_ON(state == oldstate);
+	hcrx->ccid3hcrx_state = state;
+}
+
+static void ccid3_hc_rx_send_feedback(struct sock *sk,
+				      const struct sk_buff *skb,
+				      enum ccid3_fback_type fbtype)
+{
+	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
+	struct dccp_sock *dp = dccp_sk(sk);
+	ktime_t now;
+	s64 delta = 0;
+
+	if (unlikely(hcrx->ccid3hcrx_state == TFRC_RSTATE_TERM))
+		return;
+
+	now = ktime_get_real();
+
+	switch (fbtype) {
+	case CCID3_FBACK_INITIAL:
+		hcrx->ccid3hcrx_x_recv = 0;
+		hcrx->ccid3hcrx_pinv   = ~0U;   /* see RFC 4342, 8.5 */
+		break;
+	case CCID3_FBACK_PARAM_CHANGE:
+		/*
+		 * When parameters change (new loss or p > p_prev), we do not
+		 * have a reliable estimate for R_m of [RFC 3448, 6.2] and so
+		 * need to  reuse the previous value of X_recv. However, when
+		 * X_recv was 0 (due to early loss), this would kill X down to
+		 * s/t_mbi (i.e. one packet in 64 seconds).
+		 * To avoid such drastic reduction, we approximate X_recv as
+		 * the number of bytes since last feedback.
+		 * This is a safe fallback, since X is bounded above by X_calc.
+		 */
+		if (hcrx->ccid3hcrx_x_recv > 0)
+			break;
+		/* fall through */
+	case CCID3_FBACK_PERIODIC:
+		delta = ktime_us_delta(now, hcrx->ccid3hcrx_tstamp_last_feedback);
+		if (delta <= 0)
+			DCCP_BUG("delta (%ld) <= 0", (long)delta);
+		else
+			hcrx->ccid3hcrx_x_recv =
+				scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
+		break;
+	default:
+		return;
+	}
+
+	ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", (long)delta,
+		       hcrx->ccid3hcrx_x_recv, hcrx->ccid3hcrx_pinv);
+
+	hcrx->ccid3hcrx_tstamp_last_feedback = now;
+	hcrx->ccid3hcrx_last_counter	     = dccp_hdr(skb)->dccph_ccval;
+	hcrx->ccid3hcrx_bytes_recv	     = 0;
+
+	dp->dccps_hc_rx_insert_options = 1;
+	dccp_send_ack(sk);
+}
+
+static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
+{
+	const struct ccid3_hc_rx_sock *hcrx;
+	__be32 x_recv, pinv;
+
+	if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
+		return 0;
+
+	hcrx = ccid3_hc_rx_sk(sk);
+
+	if (dccp_packet_without_ack(skb))
+		return 0;
+
+	x_recv = htonl(hcrx->ccid3hcrx_x_recv);
+	pinv   = htonl(hcrx->ccid3hcrx_pinv);
+
+	if (dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
+			       &pinv, sizeof(pinv)) ||
+	    dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
+			       &x_recv, sizeof(x_recv)))
+		return -1;
+
+	return 0;
+}
+
+/** ccid3_first_li  -  Implements [RFC 3448, 6.3.1]
+ *
+ * Determine the length of the first loss interval via inverse lookup.
+ * Assume that X_recv can be computed by the throughput equation
+ *		    s
+ *	X_recv = --------
+ *		 R * fval
+ * Find some p such that f(p) = fval; return 1/p (scaled).
+ */
+static u32 ccid3_first_li(struct sock *sk)
+{
+	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
+	u32 x_recv, p, delta;
+	u64 fval;
+
+	if (hcrx->ccid3hcrx_rtt == 0) {
+		DCCP_WARN("No RTT estimate available, using fallback RTT\n");
+		hcrx->ccid3hcrx_rtt = DCCP_FALLBACK_RTT;
+	}
+
+	delta = ktime_to_us(net_timedelta(hcrx->ccid3hcrx_tstamp_last_feedback));
+	x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
+	if (x_recv == 0) {		/* would also trigger divide-by-zero */
+		DCCP_WARN("X_recv==0\n");
+		if ((x_recv = hcrx->ccid3hcrx_x_recv) == 0) {
+			DCCP_BUG("stored value of X_recv is zero");
+			return ~0U;
+		}
+	}
+
+	fval = scaled_div(hcrx->ccid3hcrx_s, hcrx->ccid3hcrx_rtt);
+	fval = scaled_div32(fval, x_recv);
+	p = tfrc_calc_x_reverse_lookup(fval);
+
+	ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
+		       "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
+
+	return p == 0 ? ~0U : scaled_div(1, p);
+}
+
+static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
+{
+	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
+	enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE;
+	const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;
+	const bool is_data_packet = dccp_data_packet(skb);
+
+	if (unlikely(hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)) {
+		if (is_data_packet) {
+			const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
+			do_feedback = CCID3_FBACK_INITIAL;
+			ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
+			hcrx->ccid3hcrx_s = payload;
+			/*
+			 * Not necessary to update ccid3hcrx_bytes_recv here,
+			 * since X_recv = 0 for the first feedback packet (cf.
+			 * RFC 3448, 6.3) -- gerrit
+			 */
+		}
+		goto update_records;
+	}
+
+	if (tfrc_rx_hist_duplicate(&hcrx->ccid3hcrx_hist, skb))
+		return; /* done receiving */
+
+	if (is_data_packet) {
+		const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
+		/*
+		 * Update moving-average of s and the sum of received payload bytes
+		 */
+		hcrx->ccid3hcrx_s = tfrc_ewma(hcrx->ccid3hcrx_s, payload, 9);
+		hcrx->ccid3hcrx_bytes_recv += payload;
+	}
+
+	/*
+	 * Perform loss detection and handle pending losses
+	 */
+	if (tfrc_rx_handle_loss(&hcrx->ccid3hcrx_hist, &hcrx->ccid3hcrx_li_hist,
+				skb, ndp, ccid3_first_li, sk)) {
+		do_feedback = CCID3_FBACK_PARAM_CHANGE;
+		goto done_receiving;
+	}
+
+	if (tfrc_rx_hist_loss_pending(&hcrx->ccid3hcrx_hist))
+		return; /* done receiving */
+
+	/*
+	 * Handle data packets: RTT sampling and monitoring p
+	 */
+	if (unlikely(!is_data_packet))
+		goto update_records;
+
+	if (!tfrc_lh_is_initialised(&hcrx->ccid3hcrx_li_hist)) {
+		const u32 sample = tfrc_rx_hist_sample_rtt(&hcrx->ccid3hcrx_hist, skb);
+		/*
+		 * Empty loss history: no loss so far, hence p stays 0.
+		 * Sample RTT values, since an RTT estimate is required for the
+		 * computation of p when the first loss occurs; RFC 3448, 6.3.1.
+		 */
+		if (sample != 0)
+			hcrx->ccid3hcrx_rtt = tfrc_ewma(hcrx->ccid3hcrx_rtt, sample, 9);
+
+	} else if (tfrc_lh_update_i_mean(&hcrx->ccid3hcrx_li_hist, skb)) {
+		/*
+		 * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean
+		 * has decreased (resp. p has increased), send feedback now.
+		 */
+		do_feedback = CCID3_FBACK_PARAM_CHANGE;
+	}
+
+	/*
+	 * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3
+	 */
+	if (SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->ccid3hcrx_last_counter) > 3)
+		do_feedback = CCID3_FBACK_PERIODIC;
+
+update_records:
+	tfrc_rx_hist_add_packet(&hcrx->ccid3hcrx_hist, skb, ndp);
+
+done_receiving:
+	if (do_feedback)
+		ccid3_hc_rx_send_feedback(sk, skb, do_feedback);
+}
+
+static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
+{
+	struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
+
+	hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
+	tfrc_lh_init(&hcrx->ccid3hcrx_li_hist);
+	return tfrc_rx_hist_alloc(&hcrx->ccid3hcrx_hist);
+}
+
+static void ccid3_hc_rx_exit(struct sock *sk)
+{
+	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
+
+	ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
+
+	tfrc_rx_hist_purge(&hcrx->ccid3hcrx_hist);
+	tfrc_lh_cleanup(&hcrx->ccid3hcrx_li_hist);
+}
+
+static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
+{
+	const struct ccid3_hc_rx_sock *hcrx;
+
+	/* Listen socks doesn't have a private CCID block */
+	if (sk->sk_state == DCCP_LISTEN)
+		return;
+
+	hcrx = ccid3_hc_rx_sk(sk);
+	info->tcpi_ca_state = hcrx->ccid3hcrx_state;
+	info->tcpi_options  |= TCPI_OPT_TIMESTAMPS;
+	info->tcpi_rcv_rtt  = hcrx->ccid3hcrx_rtt;
+}
+
+static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
+				  u32 __user *optval, int __user *optlen)
+{
+	const struct ccid3_hc_rx_sock *hcrx;
+	struct tfrc_rx_info rx_info;
+	const void *val;
+
+	/* Listen socks doesn't have a private CCID block */
+	if (sk->sk_state == DCCP_LISTEN)
+		return -EINVAL;
+
+	hcrx = ccid3_hc_rx_sk(sk);
+	switch (optname) {
+	case DCCP_SOCKOPT_CCID_RX_INFO:
+		if (len < sizeof(rx_info))
+			return -EINVAL;
+		rx_info.tfrcrx_x_recv = hcrx->ccid3hcrx_x_recv;
+		rx_info.tfrcrx_rtt    = hcrx->ccid3hcrx_rtt;
+		rx_info.tfrcrx_p      = hcrx->ccid3hcrx_pinv == 0 ? ~0U :
+					   scaled_div(1, hcrx->ccid3hcrx_pinv);
+		len = sizeof(rx_info);
+		val = &rx_info;
+		break;
+	default:
+		return -ENOPROTOOPT;
+	}
+
+	if (put_user(len, optlen) || copy_to_user(optval, val, len))
+		return -EFAULT;
+
+	return 0;
+}
+
+static struct ccid_operations ccid3 = {
+	.ccid_id		   = DCCPC_CCID3,
+	.ccid_name		   = "TCP-Friendly Rate Control",
+	.ccid_owner		   = THIS_MODULE,
+	.ccid_hc_tx_obj_size	   = sizeof(struct ccid3_hc_tx_sock),
+	.ccid_hc_tx_init	   = ccid3_hc_tx_init,
+	.ccid_hc_tx_exit	   = ccid3_hc_tx_exit,
+	.ccid_hc_tx_send_packet	   = ccid3_hc_tx_send_packet,
+	.ccid_hc_tx_packet_sent	   = ccid3_hc_tx_packet_sent,
+	.ccid_hc_tx_packet_recv	   = ccid3_hc_tx_packet_recv,
+	.ccid_hc_tx_parse_options  = ccid3_hc_tx_parse_options,
+	.ccid_hc_rx_obj_size	   = sizeof(struct ccid3_hc_rx_sock),
+	.ccid_hc_rx_init	   = ccid3_hc_rx_init,
+	.ccid_hc_rx_exit	   = ccid3_hc_rx_exit,
+	.ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
+	.ccid_hc_rx_packet_recv	   = ccid3_hc_rx_packet_recv,
+	.ccid_hc_rx_get_info	   = ccid3_hc_rx_get_info,
+	.ccid_hc_tx_get_info	   = ccid3_hc_tx_get_info,
+	.ccid_hc_rx_getsockopt	   = ccid3_hc_rx_getsockopt,
+	.ccid_hc_tx_getsockopt	   = ccid3_hc_tx_getsockopt,
+};
+
+#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
+module_param(ccid3_debug, bool, 0644);
+MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
+#endif
+
+static __init int ccid3_module_init(void)
+{
+	return ccid_register(&ccid3);
+}
+module_init(ccid3_module_init);
+
+static __exit void ccid3_module_exit(void)
+{
+	ccid_unregister(&ccid3);
+}
+module_exit(ccid3_module_exit);
+
+MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
+	      "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
+MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("net-dccp-ccid-3");
diff --git a/net/dccp/ccids/ccid3.h b/net/dccp/ccids/ccid3.h
new file mode 100644
index 0000000..49ca32b
--- /dev/null
+++ b/net/dccp/ccids/ccid3.h
@@ -0,0 +1,171 @@
+/*
+ *  net/dccp/ccids/ccid3.h
+ *
+ *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
+ *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
+ *
+ *  An implementation of the DCCP protocol
+ *
+ *  This code has been developed by the University of Waikato WAND
+ *  research group. For further information please see http://www.wand.net.nz/
+ *  or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
+ *
+ *  This code also uses code from Lulea University, rereleased as GPL by its
+ *  authors:
+ *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
+ *
+ *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
+ *  and to make it work as a loadable module in the DCCP stack written by
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
+ *
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#ifndef _DCCP_CCID3_H_
+#define _DCCP_CCID3_H_
+
+#include <linux/ktime.h>
+#include <linux/list.h>
+#include <linux/types.h>
+#include <linux/tfrc.h>
+#include "lib/tfrc.h"
+#include "../ccid.h"
+
+/* Two seconds as per RFC 3448 4.2 */
+#define TFRC_INITIAL_TIMEOUT	   (2 * USEC_PER_SEC)
+
+/* In usecs - half the scheduling granularity as per RFC3448 4.6 */
+#define TFRC_OPSYS_HALF_TIME_GRAN  (USEC_PER_SEC / (2 * HZ))
+
+/* Parameter t_mbi from [RFC 3448, 4.3]: backoff interval in seconds */
+#define TFRC_T_MBI		   64
+
+enum ccid3_options {
+	TFRC_OPT_LOSS_EVENT_RATE = 192,
+	TFRC_OPT_LOSS_INTERVALS	 = 193,
+	TFRC_OPT_RECEIVE_RATE	 = 194,
+};
+
+struct ccid3_options_received {
+	u64 ccid3or_seqno:48,
+	    ccid3or_loss_intervals_idx:16;
+	u16 ccid3or_loss_intervals_len;
+	u32 ccid3or_loss_event_rate;
+	u32 ccid3or_receive_rate;
+};
+
+/* TFRC sender states */
+enum ccid3_hc_tx_states {
+	TFRC_SSTATE_NO_SENT = 1,
+	TFRC_SSTATE_NO_FBACK,
+	TFRC_SSTATE_FBACK,
+	TFRC_SSTATE_TERM,
+};
+
+/** struct ccid3_hc_tx_sock - CCID3 sender half-connection socket
+ *
+ * @ccid3hctx_x - Current sending rate in 64 * bytes per second
+ * @ccid3hctx_x_recv - Receive rate    in 64 * bytes per second
+ * @ccid3hctx_x_calc - Calculated rate in bytes per second
+ * @ccid3hctx_rtt - Estimate of current round trip time in usecs
+ * @ccid3hctx_p - Current loss event rate (0-1) scaled by 1000000
+ * @ccid3hctx_s - Packet size in bytes
+ * @ccid3hctx_t_rto - Nofeedback Timer setting in usecs
+ * @ccid3hctx_t_ipi - Interpacket (send) interval (RFC 3448, 4.6) in usecs
+ * @ccid3hctx_state - Sender state, one of %ccid3_hc_tx_states
+ * @ccid3hctx_last_win_count - Last window counter sent
+ * @ccid3hctx_t_last_win_count - Timestamp of earliest packet
+ *				 with last_win_count value sent
+ * @ccid3hctx_no_feedback_timer - Handle to no feedback timer
+ * @ccid3hctx_t_ld - Time last doubled during slow start
+ * @ccid3hctx_t_nom - Nominal send time of next packet
+ * @ccid3hctx_delta - Send timer delta (RFC 3448, 4.6) in usecs
+ * @ccid3hctx_hist - Packet history
+ * @ccid3hctx_options_received - Parsed set of retrieved options
+ */
+struct ccid3_hc_tx_sock {
+	struct tfrc_tx_info		ccid3hctx_tfrc;
+#define ccid3hctx_x			ccid3hctx_tfrc.tfrctx_x
+#define ccid3hctx_x_recv		ccid3hctx_tfrc.tfrctx_x_recv
+#define ccid3hctx_x_calc		ccid3hctx_tfrc.tfrctx_x_calc
+#define ccid3hctx_rtt			ccid3hctx_tfrc.tfrctx_rtt
+#define ccid3hctx_p			ccid3hctx_tfrc.tfrctx_p
+#define ccid3hctx_t_rto			ccid3hctx_tfrc.tfrctx_rto
+#define ccid3hctx_t_ipi			ccid3hctx_tfrc.tfrctx_ipi
+	u16				ccid3hctx_s;
+	enum ccid3_hc_tx_states		ccid3hctx_state:8;
+	u8				ccid3hctx_last_win_count;
+	ktime_t				ccid3hctx_t_last_win_count;
+	struct timer_list		ccid3hctx_no_feedback_timer;
+	ktime_t				ccid3hctx_t_ld;
+	ktime_t				ccid3hctx_t_nom;
+	u32				ccid3hctx_delta;
+	struct tfrc_tx_hist_entry	*ccid3hctx_hist;
+	struct ccid3_options_received	ccid3hctx_options_received;
+};
+
+static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk)
+{
+    struct ccid3_hc_tx_sock *hctx = ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
+    BUG_ON(hctx == NULL);
+    return hctx;
+}
+
+/* TFRC receiver states */
+enum ccid3_hc_rx_states {
+	TFRC_RSTATE_NO_DATA = 1,
+	TFRC_RSTATE_DATA,
+	TFRC_RSTATE_TERM    = 127,
+};
+
+/** struct ccid3_hc_rx_sock - CCID3 receiver half-connection socket
+ *
+ *  @ccid3hcrx_x_recv  -  Receiver estimate of send rate (RFC 3448 4.3)
+ *  @ccid3hcrx_rtt  -  Receiver estimate of rtt (non-standard)
+ *  @ccid3hcrx_p  -  Current loss event rate (RFC 3448 5.4)
+ *  @ccid3hcrx_last_counter  -  Tracks window counter (RFC 4342, 8.1)
+ *  @ccid3hcrx_state  -  Receiver state, one of %ccid3_hc_rx_states
+ *  @ccid3hcrx_bytes_recv  -  Total sum of DCCP payload bytes
+ *  @ccid3hcrx_x_recv  -  Receiver estimate of send rate (RFC 3448, sec. 4.3)
+ *  @ccid3hcrx_rtt  -  Receiver estimate of RTT
+ *  @ccid3hcrx_tstamp_last_feedback  -  Time at which last feedback was sent
+ *  @ccid3hcrx_tstamp_last_ack  -  Time at which last feedback was sent
+ *  @ccid3hcrx_hist  -  Packet history (loss detection + RTT sampling)
+ *  @ccid3hcrx_li_hist  -  Loss Interval database
+ *  @ccid3hcrx_s  -  Received packet size in bytes
+ *  @ccid3hcrx_pinv  -  Inverse of Loss Event Rate (RFC 4342, sec. 8.5)
+ */
+struct ccid3_hc_rx_sock {
+	u8				ccid3hcrx_last_counter:4;
+	enum ccid3_hc_rx_states		ccid3hcrx_state:8;
+	u32				ccid3hcrx_bytes_recv;
+	u32				ccid3hcrx_x_recv;
+	u32				ccid3hcrx_rtt;
+	ktime_t				ccid3hcrx_tstamp_last_feedback;
+	struct tfrc_rx_hist		ccid3hcrx_hist;
+	struct tfrc_loss_hist		ccid3hcrx_li_hist;
+	u16				ccid3hcrx_s;
+#define ccid3hcrx_pinv			ccid3hcrx_li_hist.i_mean
+};
+
+static inline struct ccid3_hc_rx_sock *ccid3_hc_rx_sk(const struct sock *sk)
+{
+    struct ccid3_hc_rx_sock *hcrx = ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
+    BUG_ON(hcrx == NULL);
+    return hcrx;
+}
+
+#endif /* _DCCP_CCID3_H_ */
diff --git a/net/dccp/ccids/lib/Makefile b/net/dccp/ccids/lib/Makefile
new file mode 100644
index 0000000..68c93e3
--- /dev/null
+++ b/net/dccp/ccids/lib/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_IP_DCCP_TFRC_LIB) += dccp_tfrc_lib.o
+
+dccp_tfrc_lib-y := tfrc.o tfrc_equation.o packet_history.o loss_interval.o
diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
new file mode 100644
index 0000000..5b3ce06
--- /dev/null
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -0,0 +1,188 @@
+/*
+ *  net/dccp/ccids/lib/loss_interval.c
+ *
+ *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
+ *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
+ *  Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ */
+#include <net/sock.h>
+#include "tfrc.h"
+
+static struct kmem_cache  *tfrc_lh_slab  __read_mostly;
+/* Loss Interval weights from [RFC 3448, 5.4], scaled by 10 */
+static const int tfrc_lh_weights[NINTERVAL] = { 10, 10, 10, 10, 8, 6, 4, 2 };
+
+/* implements LIFO semantics on the array */
+static inline u8 LIH_INDEX(const u8 ctr)
+{
+	return (LIH_SIZE - 1 - (ctr % LIH_SIZE));
+}
+
+/* the `counter' index always points at the next entry to be populated */
+static inline struct tfrc_loss_interval *tfrc_lh_peek(struct tfrc_loss_hist *lh)
+{
+	return lh->counter ? lh->ring[LIH_INDEX(lh->counter - 1)] : NULL;
+}
+
+/* given i with 0 <= i <= k, return I_i as per the rfc3448bis notation */
+static inline u32 tfrc_lh_get_interval(struct tfrc_loss_hist *lh, const u8 i)
+{
+	BUG_ON(i >= lh->counter);
+	return lh->ring[LIH_INDEX(lh->counter - i - 1)]->li_length;
+}
+
+/*
+ *	On-demand allocation and de-allocation of entries
+ */
+static struct tfrc_loss_interval *tfrc_lh_demand_next(struct tfrc_loss_hist *lh)
+{
+	if (lh->ring[LIH_INDEX(lh->counter)] == NULL)
+		lh->ring[LIH_INDEX(lh->counter)] = kmem_cache_alloc(tfrc_lh_slab,
+								    GFP_ATOMIC);
+	return lh->ring[LIH_INDEX(lh->counter)];
+}
+
+void tfrc_lh_cleanup(struct tfrc_loss_hist *lh)
+{
+	if (!tfrc_lh_is_initialised(lh))
+		return;
+
+	for (lh->counter = 0; lh->counter < LIH_SIZE; lh->counter++)
+		if (lh->ring[LIH_INDEX(lh->counter)] != NULL) {
+			kmem_cache_free(tfrc_lh_slab,
+					lh->ring[LIH_INDEX(lh->counter)]);
+			lh->ring[LIH_INDEX(lh->counter)] = NULL;
+		}
+}
+EXPORT_SYMBOL_GPL(tfrc_lh_cleanup);
+
+static void tfrc_lh_calc_i_mean(struct tfrc_loss_hist *lh)
+{
+	u32 i_i, i_tot0 = 0, i_tot1 = 0, w_tot = 0;
+	int i, k = tfrc_lh_length(lh) - 1; /* k is as in rfc3448bis, 5.4 */
+
+	if (k <= 0)
+		return;
+
+	for (i = 0; i <= k; i++) {
+		i_i = tfrc_lh_get_interval(lh, i);
+
+		if (i < k) {
+			i_tot0 += i_i * tfrc_lh_weights[i];
+			w_tot  += tfrc_lh_weights[i];
+		}
+		if (i > 0)
+			i_tot1 += i_i * tfrc_lh_weights[i-1];
+	}
+
+	lh->i_mean = max(i_tot0, i_tot1) / w_tot;
+}
+
+/**
+ * tfrc_lh_update_i_mean  -  Update the `open' loss interval I_0
+ * For recomputing p: returns `true' if p > p_prev  <=>  1/p < 1/p_prev
+ */
+u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
+{
+	struct tfrc_loss_interval *cur = tfrc_lh_peek(lh);
+	u32 old_i_mean = lh->i_mean;
+	s64 len;
+
+	if (cur == NULL)			/* not initialised */
+		return 0;
+
+	len = dccp_delta_seqno(cur->li_seqno, DCCP_SKB_CB(skb)->dccpd_seq) + 1;
+
+	if (len - (s64)cur->li_length <= 0)	/* duplicate or reordered */
+		return 0;
+
+	if (SUB16(dccp_hdr(skb)->dccph_ccval, cur->li_ccval) > 4)
+		/*
+		 * Implements RFC 4342, 10.2:
+		 * If a packet S (skb) exists whose seqno comes `after' the one
+		 * starting the current loss interval (cur) and if the modulo-16
+		 * distance from C(cur) to C(S) is greater than 4, consider all
+		 * subsequent packets as belonging to a new loss interval. This
+		 * test is necessary since CCVal may wrap between intervals.
+		 */
+		cur->li_is_closed = 1;
+
+	if (tfrc_lh_length(lh) == 1)		/* due to RFC 3448, 6.3.1 */
+		return 0;
+
+	cur->li_length = len;
+	tfrc_lh_calc_i_mean(lh);
+
+	return (lh->i_mean < old_i_mean);
+}
+EXPORT_SYMBOL_GPL(tfrc_lh_update_i_mean);
+
+/* Determine if `new_loss' does begin a new loss interval [RFC 4342, 10.2] */
+static inline u8 tfrc_lh_is_new_loss(struct tfrc_loss_interval *cur,
+				     struct tfrc_rx_hist_entry *new_loss)
+{
+	return	dccp_delta_seqno(cur->li_seqno, new_loss->tfrchrx_seqno) > 0 &&
+		(cur->li_is_closed || SUB16(new_loss->tfrchrx_ccval, cur->li_ccval) > 4);
+}
+
+/** tfrc_lh_interval_add  -  Insert new record into the Loss Interval database
+ * @lh:		   Loss Interval database
+ * @rh:		   Receive history containing a fresh loss event
+ * @calc_first_li: Caller-dependent routine to compute length of first interval
+ * @sk:		   Used by @calc_first_li in caller-specific way (subtyping)
+ * Updates I_mean and returns 1 if a new interval has in fact been added to @lh.
+ */
+int tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh,
+			 u32 (*calc_first_li)(struct sock *), struct sock *sk)
+{
+	struct tfrc_loss_interval *cur = tfrc_lh_peek(lh), *new;
+
+	if (cur != NULL && !tfrc_lh_is_new_loss(cur, tfrc_rx_hist_loss_prev(rh)))
+		return 0;
+
+	new = tfrc_lh_demand_next(lh);
+	if (unlikely(new == NULL)) {
+		DCCP_CRIT("Cannot allocate/add loss record.");
+		return 0;
+	}
+
+	new->li_seqno	  = tfrc_rx_hist_loss_prev(rh)->tfrchrx_seqno;
+	new->li_ccval	  = tfrc_rx_hist_loss_prev(rh)->tfrchrx_ccval;
+	new->li_is_closed = 0;
+
+	if (++lh->counter == 1)
+		lh->i_mean = new->li_length = (*calc_first_li)(sk);
+	else {
+		cur->li_length = dccp_delta_seqno(cur->li_seqno, new->li_seqno);
+		new->li_length = dccp_delta_seqno(new->li_seqno,
+				  tfrc_rx_hist_last_rcv(rh)->tfrchrx_seqno) + 1;
+		if (lh->counter > (2*LIH_SIZE))
+			lh->counter -= LIH_SIZE;
+
+		tfrc_lh_calc_i_mean(lh);
+	}
+	return 1;
+}
+EXPORT_SYMBOL_GPL(tfrc_lh_interval_add);
+
+int __init tfrc_li_init(void)
+{
+	tfrc_lh_slab = kmem_cache_create("tfrc_li_hist",
+					 sizeof(struct tfrc_loss_interval), 0,
+					 SLAB_HWCACHE_ALIGN, NULL);
+	return tfrc_lh_slab == NULL ? -ENOBUFS : 0;
+}
+
+void tfrc_li_exit(void)
+{
+	if (tfrc_lh_slab != NULL) {
+		kmem_cache_destroy(tfrc_lh_slab);
+		tfrc_lh_slab = NULL;
+	}
+}
diff --git a/net/dccp/ccids/lib/loss_interval.h b/net/dccp/ccids/lib/loss_interval.h
new file mode 100644
index 0000000..246018a
--- /dev/null
+++ b/net/dccp/ccids/lib/loss_interval.h
@@ -0,0 +1,75 @@
+#ifndef _DCCP_LI_HIST_
+#define _DCCP_LI_HIST_
+/*
+ *  net/dccp/ccids/lib/loss_interval.h
+ *
+ *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
+ *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
+ *  Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the Free
+ *  Software Foundation; either version 2 of the License, or (at your option)
+ *  any later version.
+ */
+#include <linux/ktime.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+/*
+ * Number of loss intervals (RFC 4342, 8.6.1). The history size is one more than
+ * NINTERVAL, since the `open' interval I_0 is always stored as the first entry.
+ */
+#define NINTERVAL	8
+#define LIH_SIZE	(NINTERVAL + 1)
+
+/**
+ *  tfrc_loss_interval  -  Loss history record for TFRC-based protocols
+ *  @li_seqno:		Highest received seqno before the start of loss
+ *  @li_ccval:		The CCVal belonging to @li_seqno
+ *  @li_is_closed:	Whether @li_seqno is older than 1 RTT
+ *  @li_length:		Loss interval sequence length
+ */
+struct tfrc_loss_interval {
+	u64		 li_seqno:48,
+			 li_ccval:4,
+			 li_is_closed:1;
+	u32		 li_length;
+};
+
+/**
+ *  tfrc_loss_hist  -  Loss record database
+ *  @ring:	Circular queue managed in LIFO manner
+ *  @counter:	Current count of entries (can be more than %LIH_SIZE)
+ *  @i_mean:	Current Average Loss Interval [RFC 3448, 5.4]
+ */
+struct tfrc_loss_hist {
+	struct tfrc_loss_interval	*ring[LIH_SIZE];
+	u8				counter;
+	u32				i_mean;
+};
+
+static inline void tfrc_lh_init(struct tfrc_loss_hist *lh)
+{
+	memset(lh, 0, sizeof(struct tfrc_loss_hist));
+}
+
+static inline u8 tfrc_lh_is_initialised(struct tfrc_loss_hist *lh)
+{
+	return lh->counter > 0;
+}
+
+static inline u8 tfrc_lh_length(struct tfrc_loss_hist *lh)
+{
+	return min(lh->counter, (u8)LIH_SIZE);
+}
+
+struct tfrc_rx_hist;
+
+extern int  tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
+				 u32 (*first_li)(struct sock *), struct sock *);
+extern u8   tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
+extern void tfrc_lh_cleanup(struct tfrc_loss_hist *lh);
+
+#endif /* _DCCP_LI_HIST_ */
diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c
new file mode 100644
index 0000000..6cc108a
--- /dev/null
+++ b/net/dccp/ccids/lib/packet_history.c
@@ -0,0 +1,498 @@
+/*
+ *  net/dccp/packet_history.c
+ *
+ *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
+ *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
+ *
+ *  An implementation of the DCCP protocol
+ *
+ *  This code has been developed by the University of Waikato WAND
+ *  research group. For further information please see http://www.wand.net.nz/
+ *  or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
+ *
+ *  This code also uses code from Lulea University, rereleased as GPL by its
+ *  authors:
+ *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
+ *
+ *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
+ *  and to make it work as a loadable module in the DCCP stack written by
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
+ *
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/string.h>
+#include <linux/slab.h>
+#include "packet_history.h"
+#include "../../dccp.h"
+
+/**
+ *  tfrc_tx_hist_entry  -  Simple singly-linked TX history list
+ *  @next:  next oldest entry (LIFO order)
+ *  @seqno: sequence number of this entry
+ *  @stamp: send time of packet with sequence number @seqno
+ */
+struct tfrc_tx_hist_entry {
+	struct tfrc_tx_hist_entry *next;
+	u64			  seqno;
+	ktime_t			  stamp;
+};
+
+/*
+ * Transmitter History Routines
+ */
+static struct kmem_cache *tfrc_tx_hist_slab;
+
+int __init tfrc_tx_packet_history_init(void)
+{
+	tfrc_tx_hist_slab = kmem_cache_create("tfrc_tx_hist",
+					      sizeof(struct tfrc_tx_hist_entry),
+					      0, SLAB_HWCACHE_ALIGN, NULL);
+	return tfrc_tx_hist_slab == NULL ? -ENOBUFS : 0;
+}
+
+void tfrc_tx_packet_history_exit(void)
+{
+	if (tfrc_tx_hist_slab != NULL) {
+		kmem_cache_destroy(tfrc_tx_hist_slab);
+		tfrc_tx_hist_slab = NULL;
+	}
+}
+
+static struct tfrc_tx_hist_entry *
+	tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
+{
+	while (head != NULL && head->seqno != seqno)
+		head = head->next;
+
+	return head;
+}
+
+int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno)
+{
+	struct tfrc_tx_hist_entry *entry = kmem_cache_alloc(tfrc_tx_hist_slab, gfp_any());
+
+	if (entry == NULL)
+		return -ENOBUFS;
+	entry->seqno = seqno;
+	entry->stamp = ktime_get_real();
+	entry->next  = *headp;
+	*headp	     = entry;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tfrc_tx_hist_add);
+
+void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp)
+{
+	struct tfrc_tx_hist_entry *head = *headp;
+
+	while (head != NULL) {
+		struct tfrc_tx_hist_entry *next = head->next;
+
+		kmem_cache_free(tfrc_tx_hist_slab, head);
+		head = next;
+	}
+
+	*headp = NULL;
+}
+EXPORT_SYMBOL_GPL(tfrc_tx_hist_purge);
+
+u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head, const u64 seqno,
+		     const ktime_t now)
+{
+	u32 rtt = 0;
+	struct tfrc_tx_hist_entry *packet = tfrc_tx_hist_find_entry(head, seqno);
+
+	if (packet != NULL) {
+		rtt = ktime_us_delta(now, packet->stamp);
+		/*
+		 * Garbage-collect older (irrelevant) entries:
+		 */
+		tfrc_tx_hist_purge(&packet->next);
+	}
+
+	return rtt;
+}
+EXPORT_SYMBOL_GPL(tfrc_tx_hist_rtt);
+
+
+/*
+ * 	Receiver History Routines
+ */
+static struct kmem_cache *tfrc_rx_hist_slab;
+
+int __init tfrc_rx_packet_history_init(void)
+{
+	tfrc_rx_hist_slab = kmem_cache_create("tfrc_rxh_cache",
+					      sizeof(struct tfrc_rx_hist_entry),
+					      0, SLAB_HWCACHE_ALIGN, NULL);
+	return tfrc_rx_hist_slab == NULL ? -ENOBUFS : 0;
+}
+
+void tfrc_rx_packet_history_exit(void)
+{
+	if (tfrc_rx_hist_slab != NULL) {
+		kmem_cache_destroy(tfrc_rx_hist_slab);
+		tfrc_rx_hist_slab = NULL;
+	}
+}
+
+static inline void tfrc_rx_hist_entry_from_skb(struct tfrc_rx_hist_entry *entry,
+					       const struct sk_buff *skb,
+					       const u64 ndp)
+{
+	const struct dccp_hdr *dh = dccp_hdr(skb);
+
+	entry->tfrchrx_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
+	entry->tfrchrx_ccval = dh->dccph_ccval;
+	entry->tfrchrx_type  = dh->dccph_type;
+	entry->tfrchrx_ndp   = ndp;
+	entry->tfrchrx_tstamp = ktime_get_real();
+}
+
+void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
+			     const struct sk_buff *skb,
+			     const u64 ndp)
+{
+	struct tfrc_rx_hist_entry *entry = tfrc_rx_hist_last_rcv(h);
+
+	tfrc_rx_hist_entry_from_skb(entry, skb, ndp);
+}
+EXPORT_SYMBOL_GPL(tfrc_rx_hist_add_packet);
+
+/* has the packet contained in skb been seen before? */
+int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb)
+{
+	const u64 seq = DCCP_SKB_CB(skb)->dccpd_seq;
+	int i;
+
+	if (dccp_delta_seqno(tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno, seq) <= 0)
+		return 1;
+
+	for (i = 1; i <= h->loss_count; i++)
+		if (tfrc_rx_hist_entry(h, i)->tfrchrx_seqno == seq)
+			return 1;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tfrc_rx_hist_duplicate);
+
+static void tfrc_rx_hist_swap(struct tfrc_rx_hist *h, const u8 a, const u8 b)
+{
+	const u8 idx_a = tfrc_rx_hist_index(h, a),
+		 idx_b = tfrc_rx_hist_index(h, b);
+	struct tfrc_rx_hist_entry *tmp = h->ring[idx_a];
+
+	h->ring[idx_a] = h->ring[idx_b];
+	h->ring[idx_b] = tmp;
+}
+
+/*
+ * Private helper functions for loss detection.
+ *
+ * In the descriptions, `Si' refers to the sequence number of entry number i,
+ * whose NDP count is `Ni' (lower case is used for variables).
+ * Note: All __xxx_loss functions expect that a test against duplicates has been
+ *       performed already: the seqno of the skb must not be less than the seqno
+ *       of loss_prev; and it must not equal that of any valid history entry.
+ */
+static void __do_track_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u64 n1)
+{
+	u64 s0 = tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno,
+	    s1 = DCCP_SKB_CB(skb)->dccpd_seq;
+
+	if (!dccp_loss_free(s0, s1, n1)) {	/* gap between S0 and S1 */
+		h->loss_count = 1;
+		tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 1), skb, n1);
+	}
+}
+
+static void __one_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n2)
+{
+	u64 s0 = tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno,
+	    s1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_seqno,
+	    s2 = DCCP_SKB_CB(skb)->dccpd_seq;
+
+	if (likely(dccp_delta_seqno(s1, s2) > 0)) {	/* S1  <  S2 */
+		h->loss_count = 2;
+		tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 2), skb, n2);
+		return;
+	}
+
+	/* S0  <  S2  <  S1 */
+
+	if (dccp_loss_free(s0, s2, n2)) {
+		u64 n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp;
+
+		if (dccp_loss_free(s2, s1, n1)) {
+			/* hole is filled: S0, S2, and S1 are consecutive */
+			h->loss_count = 0;
+			h->loss_start = tfrc_rx_hist_index(h, 1);
+		} else
+			/* gap between S2 and S1: just update loss_prev */
+			tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_loss_prev(h), skb, n2);
+
+	} else {	/* gap between S0 and S2 */
+		/*
+		 * Reorder history to insert S2 between S0 and S1
+		 */
+		tfrc_rx_hist_swap(h, 0, 3);
+		h->loss_start = tfrc_rx_hist_index(h, 3);
+		tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 1), skb, n2);
+		h->loss_count = 2;
+	}
+}
+
+/* return 1 if a new loss event has been identified */
+static int __two_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n3)
+{
+	u64 s0 = tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno,
+	    s1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_seqno,
+	    s2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_seqno,
+	    s3 = DCCP_SKB_CB(skb)->dccpd_seq;
+
+	if (likely(dccp_delta_seqno(s2, s3) > 0)) {	/* S2  <  S3 */
+		h->loss_count = 3;
+		tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 3), skb, n3);
+		return 1;
+	}
+
+	/* S3  <  S2 */
+
+	if (dccp_delta_seqno(s1, s3) > 0) {		/* S1  <  S3  <  S2 */
+		/*
+		 * Reorder history to insert S3 between S1 and S2
+		 */
+		tfrc_rx_hist_swap(h, 2, 3);
+		tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 2), skb, n3);
+		h->loss_count = 3;
+		return 1;
+	}
+
+	/* S0  <  S3  <  S1 */
+
+	if (dccp_loss_free(s0, s3, n3)) {
+		u64 n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp;
+
+		if (dccp_loss_free(s3, s1, n1)) {
+			/* hole between S0 and S1 filled by S3 */
+			u64 n2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_ndp;
+
+			if (dccp_loss_free(s1, s2, n2)) {
+				/* entire hole filled by S0, S3, S1, S2 */
+				h->loss_start = tfrc_rx_hist_index(h, 2);
+				h->loss_count = 0;
+			} else {
+				/* gap remains between S1 and S2 */
+				h->loss_start = tfrc_rx_hist_index(h, 1);
+				h->loss_count = 1;
+			}
+
+		} else /* gap exists between S3 and S1, loss_count stays at 2 */
+			tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_loss_prev(h), skb, n3);
+
+		return 0;
+	}
+
+	/*
+	 * The remaining case:  S0  <  S3  <  S1  <  S2;  gap between S0 and S3
+	 * Reorder history to insert S3 between S0 and S1.
+	 */
+	tfrc_rx_hist_swap(h, 0, 3);
+	h->loss_start = tfrc_rx_hist_index(h, 3);
+	tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 1), skb, n3);
+	h->loss_count = 3;
+
+	return 1;
+}
+
+/* recycle RX history records to continue loss detection if necessary */
+static void __three_after_loss(struct tfrc_rx_hist *h)
+{
+	/*
+	 * At this stage we know already that there is a gap between S0 and S1
+	 * (since S0 was the highest sequence number received before detecting
+	 * the loss). To recycle the loss record, it is	thus only necessary to
+	 * check for other possible gaps between S1/S2 and between S2/S3.
+	 */
+	u64 s1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_seqno,
+	    s2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_seqno,
+	    s3 = tfrc_rx_hist_entry(h, 3)->tfrchrx_seqno;
+	u64 n2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_ndp,
+	    n3 = tfrc_rx_hist_entry(h, 3)->tfrchrx_ndp;
+
+	if (dccp_loss_free(s1, s2, n2)) {
+
+		if (dccp_loss_free(s2, s3, n3)) {
+			/* no gap between S2 and S3: entire hole is filled */
+			h->loss_start = tfrc_rx_hist_index(h, 3);
+			h->loss_count = 0;
+		} else {
+			/* gap between S2 and S3 */
+			h->loss_start = tfrc_rx_hist_index(h, 2);
+			h->loss_count = 1;
+		}
+
+	} else {	/* gap between S1 and S2 */
+		h->loss_start = tfrc_rx_hist_index(h, 1);
+		h->loss_count = 2;
+	}
+}
+
+/**
+ *  tfrc_rx_handle_loss  -  Loss detection and further processing
+ *  @h:		    The non-empty RX history object
+ *  @lh:	    Loss Intervals database to update
+ *  @skb:	    Currently received packet
+ *  @ndp:	    The NDP count belonging to @skb
+ *  @calc_first_li: Caller-dependent computation of first loss interval in @lh
+ *  @sk:	    Used by @calc_first_li (see tfrc_lh_interval_add)
+ *  Chooses action according to pending loss, updates LI database when a new
+ *  loss was detected, and does required post-processing. Returns 1 when caller
+ *  should send feedback, 0 otherwise.
+ *  Since it also takes care of reordering during loss detection and updates the
+ *  records accordingly, the caller should not perform any more RX history
+ *  operations when loss_count is greater than 0 after calling this function.
+ */
+int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
+			struct tfrc_loss_hist *lh,
+			struct sk_buff *skb, const u64 ndp,
+			u32 (*calc_first_li)(struct sock *), struct sock *sk)
+{
+	int is_new_loss = 0;
+
+	if (h->loss_count == 0) {
+		__do_track_loss(h, skb, ndp);
+	} else if (h->loss_count == 1) {
+		__one_after_loss(h, skb, ndp);
+	} else if (h->loss_count != 2) {
+		DCCP_BUG("invalid loss_count %d", h->loss_count);
+	} else if (__two_after_loss(h, skb, ndp)) {
+		/*
+		 * Update Loss Interval database and recycle RX records
+		 */
+		is_new_loss = tfrc_lh_interval_add(lh, h, calc_first_li, sk);
+		__three_after_loss(h);
+	}
+	return is_new_loss;
+}
+EXPORT_SYMBOL_GPL(tfrc_rx_handle_loss);
+
+int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h)
+{
+	int i;
+
+	for (i = 0; i <= TFRC_NDUPACK; i++) {
+		h->ring[i] = kmem_cache_alloc(tfrc_rx_hist_slab, GFP_ATOMIC);
+		if (h->ring[i] == NULL)
+			goto out_free;
+	}
+
+	h->loss_count = h->loss_start = 0;
+	return 0;
+
+out_free:
+	while (i-- != 0) {
+		kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]);
+		h->ring[i] = NULL;
+	}
+	return -ENOBUFS;
+}
+EXPORT_SYMBOL_GPL(tfrc_rx_hist_alloc);
+
+void tfrc_rx_hist_purge(struct tfrc_rx_hist *h)
+{
+	int i;
+
+	for (i = 0; i <= TFRC_NDUPACK; ++i)
+		if (h->ring[i] != NULL) {
+			kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]);
+			h->ring[i] = NULL;
+		}
+}
+EXPORT_SYMBOL_GPL(tfrc_rx_hist_purge);
+
+/**
+ * tfrc_rx_hist_rtt_last_s - reference entry to compute RTT samples against
+ */
+static inline struct tfrc_rx_hist_entry *
+			tfrc_rx_hist_rtt_last_s(const struct tfrc_rx_hist *h)
+{
+	return h->ring[0];
+}
+
+/**
+ * tfrc_rx_hist_rtt_prev_s: previously suitable (wrt rtt_last_s) RTT-sampling entry
+ */
+static inline struct tfrc_rx_hist_entry *
+			tfrc_rx_hist_rtt_prev_s(const struct tfrc_rx_hist *h)
+{
+	return h->ring[h->rtt_sample_prev];
+}
+
+/**
+ * tfrc_rx_hist_sample_rtt  -  Sample RTT from timestamp / CCVal
+ * Based on ideas presented in RFC 4342, 8.1. Returns 0 if it was not able
+ * to compute a sample with given data - calling function should check this.
+ */
+u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, const struct sk_buff *skb)
+{
+	u32 sample = 0,
+	    delta_v = SUB16(dccp_hdr(skb)->dccph_ccval,
+			    tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
+
+	if (delta_v < 1 || delta_v > 4) {	/* unsuitable CCVal delta */
+		if (h->rtt_sample_prev == 2) {	/* previous candidate stored */
+			sample = SUB16(tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_ccval,
+				       tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
+			if (sample)
+				sample = 4 / sample *
+				         ktime_us_delta(tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_tstamp,
+							tfrc_rx_hist_rtt_last_s(h)->tfrchrx_tstamp);
+			else    /*
+				 * FIXME: This condition is in principle not
+				 * possible but occurs when CCID is used for
+				 * two-way data traffic. I have tried to trace
+				 * it, but the cause does not seem to be here.
+				 */
+				DCCP_BUG("please report to dccp@vger.kernel.org"
+					 " => prev = %u, last = %u",
+					 tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_ccval,
+					 tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
+		} else if (delta_v < 1) {
+			h->rtt_sample_prev = 1;
+			goto keep_ref_for_next_time;
+		}
+
+	} else if (delta_v == 4) /* optimal match */
+		sample = ktime_to_us(net_timedelta(tfrc_rx_hist_rtt_last_s(h)->tfrchrx_tstamp));
+	else {			 /* suboptimal match */
+		h->rtt_sample_prev = 2;
+		goto keep_ref_for_next_time;
+	}
+
+	if (unlikely(sample > DCCP_SANE_RTT_MAX)) {
+		DCCP_WARN("RTT sample %u too large, using max\n", sample);
+		sample = DCCP_SANE_RTT_MAX;
+	}
+
+	h->rtt_sample_prev = 0;	       /* use current entry as next reference */
+keep_ref_for_next_time:
+
+	return sample;
+}
+EXPORT_SYMBOL_GPL(tfrc_rx_hist_sample_rtt);
diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h
new file mode 100644
index 0000000..461cc91
--- /dev/null
+++ b/net/dccp/ccids/lib/packet_history.h
@@ -0,0 +1,143 @@
+/*
+ *  Packet RX/TX history data structures and routines for TFRC-based protocols.
+ *
+ *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
+ *  Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
+ *
+ *  This code has been developed by the University of Waikato WAND
+ *  research group. For further information please see http://www.wand.net.nz/
+ *  or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
+ *
+ *  This code also uses code from Lulea University, rereleased as GPL by its
+ *  authors:
+ *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
+ *
+ *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
+ *  and to make it work as a loadable module in the DCCP stack written by
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
+ *
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef _DCCP_PKT_HIST_
+#define _DCCP_PKT_HIST_
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include "tfrc.h"
+
+struct tfrc_tx_hist_entry;
+
+extern int  tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno);
+extern void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp);
+extern u32  tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head,
+			     const u64 seqno, const ktime_t now);
+
+/* Subtraction a-b modulo-16, respects circular wrap-around */
+#define SUB16(a, b) (((a) + 16 - (b)) & 0xF)
+
+/* Number of packets to wait after a missing packet (RFC 4342, 6.1) */
+#define TFRC_NDUPACK 3
+
+/**
+ * tfrc_rx_hist_entry - Store information about a single received packet
+ * @tfrchrx_seqno:	DCCP packet sequence number
+ * @tfrchrx_ccval:	window counter value of packet (RFC 4342, 8.1)
+ * @tfrchrx_ndp:	the NDP count (if any) of the packet
+ * @tfrchrx_tstamp:	actual receive time of packet
+ */
+struct tfrc_rx_hist_entry {
+	u64		 tfrchrx_seqno:48,
+			 tfrchrx_ccval:4,
+			 tfrchrx_type:4;
+	u64		 tfrchrx_ndp:48;
+	ktime_t		 tfrchrx_tstamp;
+};
+
+/**
+ * tfrc_rx_hist  -  RX history structure for TFRC-based protocols
+ *
+ * @ring:		Packet history for RTT sampling and loss detection
+ * @loss_count:		Number of entries in circular history
+ * @loss_start:		Movable index (for loss detection)
+ * @rtt_sample_prev:	Used during RTT sampling, points to candidate entry
+ */
+struct tfrc_rx_hist {
+	struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1];
+	u8			  loss_count:2,
+				  loss_start:2;
+#define rtt_sample_prev		  loss_start
+};
+
+/**
+ * tfrc_rx_hist_index - index to reach n-th entry after loss_start
+ */
+static inline u8 tfrc_rx_hist_index(const struct tfrc_rx_hist *h, const u8 n)
+{
+	return (h->loss_start + n) & TFRC_NDUPACK;
+}
+
+/**
+ * tfrc_rx_hist_last_rcv - entry with highest-received-seqno so far
+ */
+static inline struct tfrc_rx_hist_entry *
+			tfrc_rx_hist_last_rcv(const struct tfrc_rx_hist *h)
+{
+	return h->ring[tfrc_rx_hist_index(h, h->loss_count)];
+}
+
+/**
+ * tfrc_rx_hist_entry - return the n-th history entry after loss_start
+ */
+static inline struct tfrc_rx_hist_entry *
+			tfrc_rx_hist_entry(const struct tfrc_rx_hist *h, const u8 n)
+{
+	return h->ring[tfrc_rx_hist_index(h, n)];
+}
+
+/**
+ * tfrc_rx_hist_loss_prev - entry with highest-received-seqno before loss was detected
+ */
+static inline struct tfrc_rx_hist_entry *
+			tfrc_rx_hist_loss_prev(const struct tfrc_rx_hist *h)
+{
+	return h->ring[h->loss_start];
+}
+
+/* indicate whether previously a packet was detected missing */
+static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h)
+{
+	return h->loss_count > 0;
+}
+
+extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
+				    const struct sk_buff *skb, const u64 ndp);
+
+extern int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb);
+
+struct tfrc_loss_hist;
+extern int  tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
+				struct tfrc_loss_hist *lh,
+				struct sk_buff *skb, const u64 ndp,
+				u32 (*first_li)(struct sock *sk),
+				struct sock *sk);
+extern u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h,
+				   const struct sk_buff *skb);
+extern int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h);
+extern void tfrc_rx_hist_purge(struct tfrc_rx_hist *h);
+
+#endif /* _DCCP_PKT_HIST_ */
diff --git a/net/dccp/ccids/lib/tfrc.c b/net/dccp/ccids/lib/tfrc.c
new file mode 100644
index 0000000..1859162
--- /dev/null
+++ b/net/dccp/ccids/lib/tfrc.c
@@ -0,0 +1,55 @@
+/*
+ * TFRC: main module holding the pieces of the TFRC library together
+ *
+ * Copyright (c) 2007 The University of Aberdeen, Scotland, UK
+ * Copyright (c) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
+ */
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include "tfrc.h"
+
+#ifdef CONFIG_IP_DCCP_TFRC_DEBUG
+int tfrc_debug;
+module_param(tfrc_debug, bool, 0644);
+MODULE_PARM_DESC(tfrc_debug, "Enable debug messages");
+#endif
+
+static int __init tfrc_module_init(void)
+{
+	int rc = tfrc_li_init();
+
+	if (rc)
+		goto out;
+
+	rc = tfrc_tx_packet_history_init();
+	if (rc)
+		goto out_free_loss_intervals;
+
+	rc = tfrc_rx_packet_history_init();
+	if (rc)
+		goto out_free_tx_history;
+	return 0;
+
+out_free_tx_history:
+	tfrc_tx_packet_history_exit();
+out_free_loss_intervals:
+	tfrc_li_exit();
+out:
+	return rc;
+}
+
+static void __exit tfrc_module_exit(void)
+{
+	tfrc_rx_packet_history_exit();
+	tfrc_tx_packet_history_exit();
+	tfrc_li_exit();
+}
+
+module_init(tfrc_module_init);
+module_exit(tfrc_module_exit);
+
+MODULE_AUTHOR("Gerrit Renker <gerrit@erg.abdn.ac.uk>, "
+	      "Ian McDonald <ian.mcdonald@jandi.co.nz>, "
+	      "Arnaldo Carvalho de Melo <acme@redhat.com>");
+MODULE_DESCRIPTION("DCCP TFRC library");
+MODULE_LICENSE("GPL");
diff --git a/net/dccp/ccids/lib/tfrc.h b/net/dccp/ccids/lib/tfrc.h
new file mode 100644
index 0000000..ed98575
--- /dev/null
+++ b/net/dccp/ccids/lib/tfrc.h
@@ -0,0 +1,69 @@
+#ifndef _TFRC_H_
+#define _TFRC_H_
+/*
+ *  net/dccp/ccids/lib/tfrc.h
+ *
+ *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
+ *  Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
+ *  Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
+ *  Copyright (c) 2005   Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *  Copyright (c) 2003   Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ */
+#include <linux/types.h>
+#include <linux/math64.h>
+#include "../../dccp.h"
+/* internal includes that this module exports: */
+#include "loss_interval.h"
+#include "packet_history.h"
+
+#ifdef CONFIG_IP_DCCP_TFRC_DEBUG
+extern int tfrc_debug;
+#define tfrc_pr_debug(format, a...)	DCCP_PR_DEBUG(tfrc_debug, format, ##a)
+#else
+#define tfrc_pr_debug(format, a...)
+#endif
+
+/* integer-arithmetic divisions of type (a * 1000000)/b */
+static inline u64 scaled_div(u64 a, u64 b)
+{
+	BUG_ON(b==0);
+	return div64_u64(a * 1000000, b);
+}
+
+static inline u32 scaled_div32(u64 a, u64 b)
+{
+	u64 result = scaled_div(a, b);
+
+	if (result > UINT_MAX) {
+		DCCP_CRIT("Overflow: %llu/%llu > UINT_MAX",
+			  (unsigned long long)a, (unsigned long long)b);
+		return UINT_MAX;
+	}
+	return result;
+}
+
+/**
+ * tfrc_ewma  -  Exponentially weighted moving average
+ * @weight: Weight to be used as damping factor, in units of 1/10
+ */
+static inline u32 tfrc_ewma(const u32 avg, const u32 newval, const u8 weight)
+{
+	return avg ? (weight * avg + (10 - weight) * newval) / 10 : newval;
+}
+
+extern u32  tfrc_calc_x(u16 s, u32 R, u32 p);
+extern u32  tfrc_calc_x_reverse_lookup(u32 fvalue);
+
+extern int  tfrc_tx_packet_history_init(void);
+extern void tfrc_tx_packet_history_exit(void);
+extern int  tfrc_rx_packet_history_init(void);
+extern void tfrc_rx_packet_history_exit(void);
+
+extern int  tfrc_li_init(void);
+extern void tfrc_li_exit(void);
+#endif /* _TFRC_H_ */
diff --git a/net/dccp/ccids/lib/tfrc_equation.c b/net/dccp/ccids/lib/tfrc_equation.c
new file mode 100644
index 0000000..2f20a29
--- /dev/null
+++ b/net/dccp/ccids/lib/tfrc_equation.c
@@ -0,0 +1,697 @@
+/*
+ *  net/dccp/ccids/lib/tfrc_equation.c
+ *
+ *  Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
+ *  Copyright (c) 2005 Ian McDonald <ian.mcdonald@jandi.co.nz>
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include "../../dccp.h"
+#include "tfrc.h"
+
+#define TFRC_CALC_X_ARRSIZE 500
+#define TFRC_CALC_X_SPLIT   50000	/* 0.05 * 1000000, details below */
+#define TFRC_SMALLEST_P	    (TFRC_CALC_X_SPLIT/TFRC_CALC_X_ARRSIZE)
+
+/*
+  TFRC TCP Reno Throughput Equation Lookup Table for f(p)
+
+  The following two-column lookup table implements a part of the TCP throughput
+  equation from [RFC 3448, sec. 3.1]:
+
+				     s
+  X_calc  =  --------------------------------------------------------------
+	     R * sqrt(2*b*p/3) + (3 * t_RTO * sqrt(3*b*p/8) * (p + 32*p^3))
+
+  Where:
+	X      is the transmit rate in bytes/second
+	s      is the packet size in bytes
+	R      is the round trip time in seconds
+	p      is the loss event rate, between 0 and 1.0, of the number of loss
+		      events as a fraction of the number of packets transmitted
+	t_RTO  is the TCP retransmission timeout value in seconds
+	b      is the number of packets acknowledged by a single TCP ACK
+
+  We can assume that b = 1 and t_RTO is 4 * R. The equation now becomes:
+
+				     s
+  X_calc  =  -------------------------------------------------------
+	     R * sqrt(p*2/3) + (12 * R * sqrt(p*3/8) * (p + 32*p^3))
+
+  which we can break down into:
+
+		      s
+	X_calc  =  ---------
+		    R * f(p)
+
+  where f(p) is given for 0 < p <= 1 by:
+
+	f(p)  =  sqrt(2*p/3) + 12 * sqrt(3*p/8) *  (p + 32*p^3)
+
+  Since this is kernel code, floating-point arithmetic is avoided in favour of
+  integer arithmetic. This means that nearly all fractional parameters are
+  scaled by 1000000:
+    * the parameters p and R
+    * the return result f(p)
+  The lookup table therefore actually tabulates the following function g(q):
+
+	g(q)  =  1000000 * f(q/1000000)
+
+  Hence, when p <= 1, q must be less than or equal to 1000000. To achieve finer
+  granularity for the practically more relevant case of small values of p (up to
+  5%), the second column is used; the first one ranges up to 100%.  This split
+  corresponds to the value of q = TFRC_CALC_X_SPLIT. At the same time this also
+  determines the smallest resolution possible with this lookup table:
+
+    TFRC_SMALLEST_P   =  TFRC_CALC_X_SPLIT / TFRC_CALC_X_ARRSIZE
+
+  The entire table is generated by:
+    for(i=0; i < TFRC_CALC_X_ARRSIZE; i++) {
+	lookup[i][0]  =  g((i+1) * 1000000/TFRC_CALC_X_ARRSIZE);
+	lookup[i][1]  =  g((i+1) * TFRC_CALC_X_SPLIT/TFRC_CALC_X_ARRSIZE);
+    }
+
+  With the given configuration, we have, with M = TFRC_CALC_X_ARRSIZE-1,
+    lookup[0][0]  =  g(1000000/(M+1)) 		 =  1000000 * f(0.2%)
+    lookup[M][0]  =  g(1000000)			 =  1000000 * f(100%)
+    lookup[0][1]  =  g(TFRC_SMALLEST_P)		  = 1000000 * f(0.01%)
+    lookup[M][1]  =  g(TFRC_CALC_X_SPLIT)	 =  1000000 * f(5%)
+
+  In summary, the two columns represent f(p) for the following ranges:
+    * The first column is for   0.002  <= p <= 1.0
+    * The second column is for  0.0001 <= p <= 0.05
+  Where the columns overlap, the second (finer-grained) is given preference,
+  i.e. the first column is used only for p >= 0.05.
+ */
+static const u32 tfrc_calc_x_lookup[TFRC_CALC_X_ARRSIZE][2] = {
+	{     37172,   8172 },
+	{     53499,  11567 },
+	{     66664,  14180 },
+	{     78298,  16388 },
+	{     89021,  18339 },
+	{     99147,  20108 },
+	{    108858,  21738 },
+	{    118273,  23260 },
+	{    127474,  24693 },
+	{    136520,  26052 },
+	{    145456,  27348 },
+	{    154316,  28589 },
+	{    163130,  29783 },
+	{    171919,  30935 },
+	{    180704,  32049 },
+	{    189502,  33130 },
+	{    198328,  34180 },
+	{    207194,  35202 },
+	{    216114,  36198 },
+	{    225097,  37172 },
+	{    234153,  38123 },
+	{    243294,  39055 },
+	{    252527,  39968 },
+	{    261861,  40864 },
+	{    271305,  41743 },
+	{    280866,  42607 },
+	{    290553,  43457 },
+	{    300372,  44293 },
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+	{    330705,  46729 },
+	{    341131,  47518 },
+	{    351728,  48297 },
+	{    362501,  49066 },
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+	{ 180197813, 251599 },
+	{ 181545242, 252063 },
+	{ 182899933, 252527 },
+	{ 184261908, 252991 },
+	{ 185631191, 253456 },
+	{ 187007807, 253920 },
+	{ 188391778, 254385 },
+	{ 189783129, 254851 },
+	{ 191181884, 255316 },
+	{ 192588065, 255782 },
+	{ 194001698, 256248 },
+	{ 195422805, 256714 },
+	{ 196851411, 257181 },
+	{ 198287540, 257648 },
+	{ 199731215, 258115 },
+	{ 201182461, 258582 },
+	{ 202641302, 259050 },
+	{ 204107760, 259518 },
+	{ 205581862, 259986 },
+	{ 207063630, 260454 },
+	{ 208553088, 260923 },
+	{ 210050262, 261392 },
+	{ 211555174, 261861 },
+	{ 213067849, 262331 },
+	{ 214588312, 262800 },
+	{ 216116586, 263270 },
+	{ 217652696, 263741 },
+	{ 219196666, 264211 },
+	{ 220748520, 264682 },
+	{ 222308282, 265153 },
+	{ 223875978, 265625 },
+	{ 225451630, 266097 },
+	{ 227035265, 266569 },
+	{ 228626905, 267041 },
+	{ 230226576, 267514 },
+	{ 231834302, 267986 },
+	{ 233450107, 268460 },
+	{ 235074016, 268933 },
+	{ 236706054, 269407 },
+	{ 238346244, 269881 },
+	{ 239994613, 270355 },
+	{ 241651183, 270830 },
+	{ 243315981, 271305 }
+};
+
+/* return largest index i such that fval <= lookup[i][small] */
+static inline u32 tfrc_binsearch(u32 fval, u8 small)
+{
+	u32 try, low = 0, high = TFRC_CALC_X_ARRSIZE - 1;
+
+	while (low < high) {
+		try = (low + high) / 2;
+		if (fval <= tfrc_calc_x_lookup[try][small])
+			high = try;
+		else
+			low  = try + 1;
+	}
+	return high;
+}
+
+/**
+ * tfrc_calc_x - Calculate the send rate as per section 3.1 of RFC3448
+ *
+ *  @s: packet size          in bytes
+ *  @R: RTT                  scaled by 1000000   (i.e., microseconds)
+ *  @p: loss ratio estimate  scaled by 1000000
+ *  Returns X_calc           in bytes per second (not scaled).
+ */
+u32 tfrc_calc_x(u16 s, u32 R, u32 p)
+{
+	u16 index;
+	u32 f;
+	u64 result;
+
+	/* check against invalid parameters and divide-by-zero   */
+	BUG_ON(p >  1000000);		/* p must not exceed 100%   */
+	BUG_ON(p == 0);			/* f(0) = 0, divide by zero */
+	if (R == 0) {			/* possible  divide by zero */
+		DCCP_CRIT("WARNING: RTT is 0, returning maximum X_calc.");
+		return ~0U;
+	}
+
+	if (p <= TFRC_CALC_X_SPLIT) 		{     /* 0.0000 < p <= 0.05   */
+		if (p < TFRC_SMALLEST_P) {	      /* 0.0000 < p <  0.0001 */
+			DCCP_WARN("Value of p (%d) below resolution. "
+				  "Substituting %d\n", p, TFRC_SMALLEST_P);
+			index = 0;
+		} else 				      /* 0.0001 <= p <= 0.05  */
+			index =  p/TFRC_SMALLEST_P - 1;
+
+		f = tfrc_calc_x_lookup[index][1];
+
+	} else {	 			      /* 0.05   <  p <= 1.00  */
+		index = p/(1000000/TFRC_CALC_X_ARRSIZE) - 1;
+
+		f = tfrc_calc_x_lookup[index][0];
+	}
+
+	/*
+	 * Compute X = s/(R*f(p)) in bytes per second.
+	 * Since f(p) and R are both scaled by 1000000, we need to multiply by
+	 * 1000000^2. To avoid overflow, the result is computed in two stages.
+	 * This works under almost all reasonable operational conditions, for a
+	 * wide range of parameters. Yet, should some strange combination of
+	 * parameters result in overflow, the use of scaled_div32 will catch
+	 * this and return UINT_MAX - which is a logically adequate consequence.
+	 */
+	result = scaled_div(s, R);
+	return scaled_div32(result, f);
+}
+
+EXPORT_SYMBOL_GPL(tfrc_calc_x);
+
+/**
+ *  tfrc_calc_x_reverse_lookup  -  try to find p given f(p)
+ *
+ *  @fvalue: function value to match, scaled by 1000000
+ *  Returns closest match for p, also scaled by 1000000
+ */
+u32 tfrc_calc_x_reverse_lookup(u32 fvalue)
+{
+	int index;
+
+	if (fvalue == 0)	/* f(p) = 0  whenever  p = 0 */
+		return 0;
+
+	/* Error cases. */
+	if (fvalue < tfrc_calc_x_lookup[0][1]) {
+		DCCP_WARN("fvalue %u smaller than resolution\n", fvalue);
+		return TFRC_SMALLEST_P;
+	}
+	if (fvalue > tfrc_calc_x_lookup[TFRC_CALC_X_ARRSIZE - 1][0]) {
+		DCCP_WARN("fvalue %u exceeds bounds!\n", fvalue);
+		return 1000000;
+	}
+
+	if (fvalue <= tfrc_calc_x_lookup[TFRC_CALC_X_ARRSIZE - 1][1]) {
+		index = tfrc_binsearch(fvalue, 1);
+		return (index + 1) * TFRC_CALC_X_SPLIT / TFRC_CALC_X_ARRSIZE;
+	}
+
+	/* else ... it must be in the coarse-grained column */
+	index = tfrc_binsearch(fvalue, 0);
+	return (index + 1) * 1000000 / TFRC_CALC_X_ARRSIZE;
+}
+
+EXPORT_SYMBOL_GPL(tfrc_calc_x_reverse_lookup);
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
new file mode 100644
index 0000000..b4bc6e0
--- /dev/null
+++ b/net/dccp/dccp.h
@@ -0,0 +1,471 @@
+#ifndef _DCCP_H
+#define _DCCP_H
+/*
+ *  net/dccp/dccp.h
+ *
+ *  An implementation of the DCCP protocol
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *  Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
+ *
+ *	This program is free software; you can redistribute it and/or modify it
+ *	under the terms of the GNU General Public License version 2 as
+ *	published by the Free Software Foundation.
+ */
+
+#include <linux/dccp.h>
+#include <linux/ktime.h>
+#include <net/snmp.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+#include "ackvec.h"
+
+/*
+ * 	DCCP - specific warning and debugging macros.
+ */
+#define DCCP_WARN(fmt, a...) LIMIT_NETDEBUG(KERN_WARNING "%s: " fmt,       \
+							__func__, ##a)
+#define DCCP_CRIT(fmt, a...) printk(KERN_CRIT fmt " at %s:%d/%s()\n", ##a, \
+					 __FILE__, __LINE__, __func__)
+#define DCCP_BUG(a...)       do { DCCP_CRIT("BUG: " a); dump_stack(); } while(0)
+#define DCCP_BUG_ON(cond)    do { if (unlikely((cond) != 0))		   \
+				     DCCP_BUG("\"%s\" holds (exception!)", \
+					      __stringify(cond));          \
+			     } while (0)
+
+#define DCCP_PRINTK(enable, fmt, args...)	do { if (enable)	     \
+							printk(fmt, ##args); \
+						} while(0)
+#define DCCP_PR_DEBUG(enable, fmt, a...)	DCCP_PRINTK(enable, KERN_DEBUG \
+						  "%s: " fmt, __func__, ##a)
+
+#ifdef CONFIG_IP_DCCP_DEBUG
+extern int dccp_debug;
+#define dccp_pr_debug(format, a...)	  DCCP_PR_DEBUG(dccp_debug, format, ##a)
+#define dccp_pr_debug_cat(format, a...)   DCCP_PRINTK(dccp_debug, format, ##a)
+#else
+#define dccp_pr_debug(format, a...)
+#define dccp_pr_debug_cat(format, a...)
+#endif
+
+extern struct inet_hashinfo dccp_hashinfo;
+
+extern atomic_t dccp_orphan_count;
+
+extern void dccp_time_wait(struct sock *sk, int state, int timeo);
+
+/*
+ *  Set safe upper bounds for header and option length. Since Data Offset is 8
+ *  bits (RFC 4340, sec. 5.1), the total header length can never be more than
+ *  4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1):
+ *    - DCCP-Response with ACK Subheader and 4 bytes of Service code      OR
+ *    - DCCP-Reset    with ACK Subheader and 4 bytes of Reset Code fields
+ *  Hence a safe upper bound for the maximum option length is 1020-28 = 992
+ */
+#define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(int))
+#define DCCP_MAX_PACKET_HDR 28
+#define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR)
+#define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER)
+
+#define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
+				     * state, about 60 seconds */
+
+/* RFC 1122, 4.2.3.1 initial RTO value */
+#define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))
+
+/*
+ * The maximum back-off value for retransmissions. This is needed for
+ *  - retransmitting client-Requests (sec. 8.1.1),
+ *  - retransmitting Close/CloseReq when closing (sec. 8.3),
+ *  - feature-negotiation retransmission (sec. 6.6.3),
+ *  - Acks in client-PARTOPEN state (sec. 8.1.5).
+ */
+#define DCCP_RTO_MAX ((unsigned)(64 * HZ))
+
+/*
+ * RTT sampling: sanity bounds and fallback RTT value from RFC 4340, section 3.4
+ */
+#define DCCP_SANE_RTT_MIN	100
+#define DCCP_FALLBACK_RTT	(USEC_PER_SEC / 5)
+#define DCCP_SANE_RTT_MAX	(3 * USEC_PER_SEC)
+
+/* Maximal interval between probes for local resources.  */
+#define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))
+
+/* sysctl variables for DCCP */
+extern int  sysctl_dccp_request_retries;
+extern int  sysctl_dccp_retries1;
+extern int  sysctl_dccp_retries2;
+extern int  sysctl_dccp_feat_sequence_window;
+extern int  sysctl_dccp_feat_rx_ccid;
+extern int  sysctl_dccp_feat_tx_ccid;
+extern int  sysctl_dccp_feat_ack_ratio;
+extern int  sysctl_dccp_feat_send_ack_vector;
+extern int  sysctl_dccp_feat_send_ndp_count;
+extern int  sysctl_dccp_tx_qlen;
+extern int  sysctl_dccp_sync_ratelimit;
+
+/*
+ *	48-bit sequence number arithmetic (signed and unsigned)
+ */
+#define INT48_MIN	  0x800000000000LL		/* 2^47	    */
+#define UINT48_MAX	  0xFFFFFFFFFFFFLL		/* 2^48 - 1 */
+#define COMPLEMENT48(x)	 (0x1000000000000LL - (x))	/* 2^48 - x */
+#define TO_SIGNED48(x)	 (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x)))
+#define TO_UNSIGNED48(x) (((x) >= 0)?	     (x) :  COMPLEMENT48(-(x)))
+#define ADD48(a, b)	 (((a) + (b)) & UINT48_MAX)
+#define SUB48(a, b)	 ADD48((a), COMPLEMENT48(b))
+
+static inline void dccp_set_seqno(u64 *seqno, u64 value)
+{
+	*seqno = value & UINT48_MAX;
+}
+
+static inline void dccp_inc_seqno(u64 *seqno)
+{
+	*seqno = ADD48(*seqno, 1);
+}
+
+/* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
+static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
+{
+	u64 delta = SUB48(seqno2, seqno1);
+
+	return TO_SIGNED48(delta);
+}
+
+/* is seq1 < seq2 ? */
+static inline int before48(const u64 seq1, const u64 seq2)
+{
+	return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
+}
+
+/* is seq1 > seq2 ? */
+#define after48(seq1, seq2)	before48(seq2, seq1)
+
+/* is seq2 <= seq1 <= seq3 ? */
+static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
+{
+	return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
+}
+
+static inline u64 max48(const u64 seq1, const u64 seq2)
+{
+	return after48(seq1, seq2) ? seq1 : seq2;
+}
+
+/**
+ * dccp_loss_free  -  Evaluates condition for data loss from RFC 4340, 7.7.1
+ * @s1:	 start sequence number
+ * @s2:  end sequence number
+ * @ndp: NDP count on packet with sequence number @s2
+ * Returns true if the sequence range s1...s2 has no data loss.
+ */
+static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
+{
+	s64 delta = dccp_delta_seqno(s1, s2);
+
+	WARN_ON(delta < 0);
+	return (u64)delta <= ndp + 1;
+}
+
+enum {
+	DCCP_MIB_NUM = 0,
+	DCCP_MIB_ACTIVEOPENS,			/* ActiveOpens */
+	DCCP_MIB_ESTABRESETS,			/* EstabResets */
+	DCCP_MIB_CURRESTAB,			/* CurrEstab */
+	DCCP_MIB_OUTSEGS,			/* OutSegs */
+	DCCP_MIB_OUTRSTS,
+	DCCP_MIB_ABORTONTIMEOUT,
+	DCCP_MIB_TIMEOUTS,
+	DCCP_MIB_ABORTFAILED,
+	DCCP_MIB_PASSIVEOPENS,
+	DCCP_MIB_ATTEMPTFAILS,
+	DCCP_MIB_OUTDATAGRAMS,
+	DCCP_MIB_INERRS,
+	DCCP_MIB_OPTMANDATORYERROR,
+	DCCP_MIB_INVALIDOPT,
+	__DCCP_MIB_MAX
+};
+
+#define DCCP_MIB_MAX	__DCCP_MIB_MAX
+struct dccp_mib {
+	unsigned long	mibs[DCCP_MIB_MAX];
+} __SNMP_MIB_ALIGN__;
+
+DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
+#define DCCP_INC_STATS(field)	    SNMP_INC_STATS(dccp_statistics, field)
+#define DCCP_INC_STATS_BH(field)    SNMP_INC_STATS_BH(dccp_statistics, field)
+#define DCCP_INC_STATS_USER(field)  SNMP_INC_STATS_USER(dccp_statistics, field)
+#define DCCP_DEC_STATS(field)	    SNMP_DEC_STATS(dccp_statistics, field)
+#define DCCP_ADD_STATS_BH(field, val) \
+			SNMP_ADD_STATS_BH(dccp_statistics, field, val)
+#define DCCP_ADD_STATS_USER(field, val)	\
+			SNMP_ADD_STATS_USER(dccp_statistics, field, val)
+
+/*
+ * 	Checksumming routines
+ */
+static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb)
+{
+	const struct dccp_hdr* dh = dccp_hdr(skb);
+
+	if (dh->dccph_cscov == 0)
+		return skb->len;
+	return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
+}
+
+static inline void dccp_csum_outgoing(struct sk_buff *skb)
+{
+	unsigned int cov = dccp_csum_coverage(skb);
+
+	if (cov >= skb->len)
+		dccp_hdr(skb)->dccph_cscov = 0;
+
+	skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
+}
+
+extern void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
+
+extern int  dccp_retransmit_skb(struct sock *sk);
+
+extern void dccp_send_ack(struct sock *sk);
+extern void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
+				struct request_sock *rsk);
+
+extern void dccp_send_sync(struct sock *sk, const u64 seq,
+			   const enum dccp_pkt_type pkt_type);
+
+extern void dccp_write_xmit(struct sock *sk, int block);
+extern void dccp_write_space(struct sock *sk);
+
+extern void dccp_init_xmit_timers(struct sock *sk);
+static inline void dccp_clear_xmit_timers(struct sock *sk)
+{
+	inet_csk_clear_xmit_timers(sk);
+}
+
+extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
+
+extern const char *dccp_packet_name(const int type);
+extern const char *dccp_state_name(const int state);
+
+extern void dccp_set_state(struct sock *sk, const int state);
+extern void dccp_done(struct sock *sk);
+
+extern void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb);
+
+extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
+
+extern struct sock *dccp_create_openreq_child(struct sock *sk,
+					      const struct request_sock *req,
+					      const struct sk_buff *skb);
+
+extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
+
+extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
+					      struct sk_buff *skb,
+					      struct request_sock *req,
+					      struct dst_entry *dst);
+extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
+				   struct request_sock *req,
+				   struct request_sock **prev);
+
+extern int dccp_child_process(struct sock *parent, struct sock *child,
+			      struct sk_buff *skb);
+extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
+				  struct dccp_hdr *dh, unsigned len);
+extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
+				const struct dccp_hdr *dh, const unsigned len);
+
+extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
+extern void dccp_destroy_sock(struct sock *sk);
+
+extern void		dccp_close(struct sock *sk, long timeout);
+extern struct sk_buff	*dccp_make_response(struct sock *sk,
+					    struct dst_entry *dst,
+					    struct request_sock *req);
+
+extern int	   dccp_connect(struct sock *sk);
+extern int	   dccp_disconnect(struct sock *sk, int flags);
+extern int	   dccp_getsockopt(struct sock *sk, int level, int optname,
+				   char __user *optval, int __user *optlen);
+extern int	   dccp_setsockopt(struct sock *sk, int level, int optname,
+				   char __user *optval, int optlen);
+#ifdef CONFIG_COMPAT
+extern int	   compat_dccp_getsockopt(struct sock *sk,
+				int level, int optname,
+				char __user *optval, int __user *optlen);
+extern int	   compat_dccp_setsockopt(struct sock *sk,
+				int level, int optname,
+				char __user *optval, int optlen);
+#endif
+extern int	   dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
+extern int	   dccp_sendmsg(struct kiocb *iocb, struct sock *sk,
+				struct msghdr *msg, size_t size);
+extern int	   dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
+				struct msghdr *msg, size_t len, int nonblock,
+				int flags, int *addr_len);
+extern void	   dccp_shutdown(struct sock *sk, int how);
+extern int	   inet_dccp_listen(struct socket *sock, int backlog);
+extern unsigned int dccp_poll(struct file *file, struct socket *sock,
+			     poll_table *wait);
+extern int	   dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
+				   int addr_len);
+
+extern struct sk_buff *dccp_ctl_make_reset(struct sock *sk,
+					   struct sk_buff *skb);
+extern int	   dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
+extern void	   dccp_send_close(struct sock *sk, const int active);
+extern int	   dccp_invalid_packet(struct sk_buff *skb);
+extern u32	   dccp_sample_rtt(struct sock *sk, long delta);
+
+static inline int dccp_bad_service_code(const struct sock *sk,
+					const __be32 service)
+{
+	const struct dccp_sock *dp = dccp_sk(sk);
+
+	if (dp->dccps_service == service)
+		return 0;
+	return !dccp_list_has_service(dp->dccps_service_list, service);
+}
+
+/**
+ * dccp_skb_cb  -  DCCP per-packet control information
+ * @dccpd_type: one of %dccp_pkt_type (or unknown)
+ * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1
+ * @dccpd_reset_code: one of %dccp_reset_codes
+ * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code)
+ * @dccpd_opt_len: total length of all options (5.8) in the packet
+ * @dccpd_seq: sequence number
+ * @dccpd_ack_seq: acknowledgment number subheader field value
+ * This is used for transmission as well as for reception.
+ */
+struct dccp_skb_cb {
+	union {
+		struct inet_skb_parm	h4;
+#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
+		struct inet6_skb_parm	h6;
+#endif
+	} header;
+	__u8  dccpd_type:4;
+	__u8  dccpd_ccval:4;
+	__u8  dccpd_reset_code,
+	      dccpd_reset_data[3];
+	__u16 dccpd_opt_len;
+	__u64 dccpd_seq;
+	__u64 dccpd_ack_seq;
+};
+
+#define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
+
+/* RFC 4340, sec. 7.7 */
+static inline int dccp_non_data_packet(const struct sk_buff *skb)
+{
+	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
+
+	return type == DCCP_PKT_ACK	 ||
+	       type == DCCP_PKT_CLOSE	 ||
+	       type == DCCP_PKT_CLOSEREQ ||
+	       type == DCCP_PKT_RESET	 ||
+	       type == DCCP_PKT_SYNC	 ||
+	       type == DCCP_PKT_SYNCACK;
+}
+
+/* RFC 4340, sec. 7.7 */
+static inline int dccp_data_packet(const struct sk_buff *skb)
+{
+	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
+
+	return type == DCCP_PKT_DATA	 ||
+	       type == DCCP_PKT_DATAACK  ||
+	       type == DCCP_PKT_REQUEST  ||
+	       type == DCCP_PKT_RESPONSE;
+}
+
+static inline int dccp_packet_without_ack(const struct sk_buff *skb)
+{
+	const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
+
+	return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
+}
+
+#define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
+
+static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
+{
+	struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
+							   sizeof(*dh));
+	dh->dccph_seq2 = 0;
+	dh->dccph_seq = htons((gss >> 32) & 0xfffff);
+	dhx->dccph_seq_low = htonl(gss & 0xffffffff);
+}
+
+static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
+				    const u64 gsr)
+{
+	dhack->dccph_reserved1 = 0;
+	dhack->dccph_ack_nr_high = htons(gsr >> 32);
+	dhack->dccph_ack_nr_low  = htonl(gsr & 0xffffffff);
+}
+
+static inline void dccp_update_gsr(struct sock *sk, u64 seq)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	const struct dccp_minisock *dmsk = dccp_msk(sk);
+
+	dp->dccps_gsr = seq;
+	dccp_set_seqno(&dp->dccps_swl,
+		       dp->dccps_gsr + 1 - (dmsk->dccpms_sequence_window / 4));
+	dccp_set_seqno(&dp->dccps_swh,
+		       dp->dccps_gsr + (3 * dmsk->dccpms_sequence_window) / 4);
+}
+
+static inline void dccp_update_gss(struct sock *sk, u64 seq)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+
+	dp->dccps_awh = dp->dccps_gss = seq;
+	dccp_set_seqno(&dp->dccps_awl,
+		       (dp->dccps_gss -
+			dccp_msk(sk)->dccpms_sequence_window + 1));
+}
+
+static inline int dccp_ack_pending(const struct sock *sk)
+{
+	const struct dccp_sock *dp = dccp_sk(sk);
+	return dp->dccps_timestamp_echo != 0 ||
+#ifdef CONFIG_IP_DCCP_ACKVEC
+	       (dccp_msk(sk)->dccpms_send_ack_vector &&
+		dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
+#endif
+	       inet_csk_ack_scheduled(sk);
+}
+
+extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
+extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);
+extern int dccp_insert_option_elapsed_time(struct sock *sk,
+					    struct sk_buff *skb,
+					    u32 elapsed_time);
+extern u32 dccp_timestamp(void);
+extern void dccp_timestamping_init(void);
+extern int dccp_insert_option_timestamp(struct sock *sk,
+					 struct sk_buff *skb);
+extern int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
+			       unsigned char option,
+			       const void *value, unsigned char len);
+
+#ifdef CONFIG_SYSCTL
+extern int dccp_sysctl_init(void);
+extern void dccp_sysctl_exit(void);
+#else
+static inline int dccp_sysctl_init(void)
+{
+	return 0;
+}
+
+static inline void dccp_sysctl_exit(void)
+{
+}
+#endif
+
+#endif /* _DCCP_H */
diff --git a/net/dccp/diag.c b/net/dccp/diag.c
new file mode 100644
index 0000000..d8a3509
--- /dev/null
+++ b/net/dccp/diag.c
@@ -0,0 +1,71 @@
+/*
+ *  net/dccp/diag.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@mandriva.com>
+ *
+ *	This program is free software; you can redistribute it and/or modify it
+ *	under the terms of the GNU General Public License version 2 as
+ *	published by the Free Software Foundation.
+ */
+
+
+#include <linux/module.h>
+#include <linux/inet_diag.h>
+
+#include "ccid.h"
+#include "dccp.h"
+
+static void dccp_get_info(struct sock *sk, struct tcp_info *info)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	const struct inet_connection_sock *icsk = inet_csk(sk);
+
+	memset(info, 0, sizeof(*info));
+
+	info->tcpi_state	= sk->sk_state;
+	info->tcpi_retransmits	= icsk->icsk_retransmits;
+	info->tcpi_probes	= icsk->icsk_probes_out;
+	info->tcpi_backoff	= icsk->icsk_backoff;
+	info->tcpi_pmtu		= icsk->icsk_pmtu_cookie;
+
+	if (dccp_msk(sk)->dccpms_send_ack_vector)
+		info->tcpi_options |= TCPI_OPT_SACK;
+
+	ccid_hc_rx_get_info(dp->dccps_hc_rx_ccid, sk, info);
+	ccid_hc_tx_get_info(dp->dccps_hc_tx_ccid, sk, info);
+}
+
+static void dccp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
+			       void *_info)
+{
+	r->idiag_rqueue = r->idiag_wqueue = 0;
+
+	if (_info != NULL)
+		dccp_get_info(sk, _info);
+}
+
+static struct inet_diag_handler dccp_diag_handler = {
+	.idiag_hashinfo	 = &dccp_hashinfo,
+	.idiag_get_info	 = dccp_diag_get_info,
+	.idiag_type	 = DCCPDIAG_GETSOCK,
+	.idiag_info_size = sizeof(struct tcp_info),
+};
+
+static int __init dccp_diag_init(void)
+{
+	return inet_diag_register(&dccp_diag_handler);
+}
+
+static void __exit dccp_diag_fini(void)
+{
+	inet_diag_unregister(&dccp_diag_handler);
+}
+
+module_init(dccp_diag_init);
+module_exit(dccp_diag_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
+MODULE_DESCRIPTION("DCCP inet_diag handler");
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_INET_DIAG, DCCPDIAG_GETSOCK);
diff --git a/net/dccp/feat.c b/net/dccp/feat.c
new file mode 100644
index 0000000..933a0ec
--- /dev/null
+++ b/net/dccp/feat.c
@@ -0,0 +1,649 @@
+/*
+ *  net/dccp/feat.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Andrea Bittau <a.bittau@cs.ucl.ac.uk>
+ *
+ *  ASSUMPTIONS
+ *  -----------
+ *  o All currently known SP features have 1-byte quantities. If in the future
+ *    extensions of RFCs 4340..42 define features with item lengths larger than
+ *    one byte, a feature-specific extension of the code will be required.
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+
+#include "ccid.h"
+#include "feat.h"
+
+#define DCCP_FEAT_SP_NOAGREE (-123)
+
+int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
+		     u8 *val, u8 len, gfp_t gfp)
+{
+	struct dccp_opt_pend *opt;
+
+	dccp_feat_debug(type, feature, *val);
+
+	if (len > 3) {
+		DCCP_WARN("invalid length %d\n", len);
+		return -EINVAL;
+	}
+	/* XXX add further sanity checks */
+
+	/* check if that feature is already being negotiated */
+	list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
+		/* ok we found a negotiation for this option already */
+		if (opt->dccpop_feat == feature && opt->dccpop_type == type) {
+			dccp_pr_debug("Replacing old\n");
+			/* replace */
+			BUG_ON(opt->dccpop_val == NULL);
+			kfree(opt->dccpop_val);
+			opt->dccpop_val	 = val;
+			opt->dccpop_len	 = len;
+			opt->dccpop_conf = 0;
+			return 0;
+		}
+	}
+
+	/* negotiation for a new feature */
+	opt = kmalloc(sizeof(*opt), gfp);
+	if (opt == NULL)
+		return -ENOMEM;
+
+	opt->dccpop_type = type;
+	opt->dccpop_feat = feature;
+	opt->dccpop_len	 = len;
+	opt->dccpop_val	 = val;
+	opt->dccpop_conf = 0;
+	opt->dccpop_sc	 = NULL;
+
+	BUG_ON(opt->dccpop_val == NULL);
+
+	list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending);
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_feat_change);
+
+static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct dccp_minisock *dmsk = dccp_msk(sk);
+	/* figure out if we are changing our CCID or the peer's */
+	const int rx = type == DCCPO_CHANGE_R;
+	const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid;
+	struct ccid *new_ccid;
+
+	/* Check if nothing is being changed. */
+	if (ccid_nr == new_ccid_nr)
+		return 0;
+
+	new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
+	if (new_ccid == NULL)
+		return -ENOMEM;
+
+	if (rx) {
+		ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
+		dp->dccps_hc_rx_ccid = new_ccid;
+		dmsk->dccpms_rx_ccid = new_ccid_nr;
+	} else {
+		ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
+		dp->dccps_hc_tx_ccid = new_ccid;
+		dmsk->dccpms_tx_ccid = new_ccid_nr;
+	}
+
+	return 0;
+}
+
+static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
+{
+	dccp_feat_debug(type, feat, val);
+
+	switch (feat) {
+	case DCCPF_CCID:
+		return dccp_feat_update_ccid(sk, type, val);
+	default:
+		dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
+			      dccp_feat_typename(type), feat);
+		break;
+	}
+	return 0;
+}
+
+static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
+			       u8 *rpref, u8 rlen)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	u8 *spref, slen, *res = NULL;
+	int i, j, rc, agree = 1;
+
+	BUG_ON(rpref == NULL);
+
+	/* check if we are the black sheep */
+	if (dp->dccps_role == DCCP_ROLE_CLIENT) {
+		spref = rpref;
+		slen  = rlen;
+		rpref = opt->dccpop_val;
+		rlen  = opt->dccpop_len;
+	} else {
+		spref = opt->dccpop_val;
+		slen  = opt->dccpop_len;
+	}
+	/*
+	 * Now we have server preference list in spref and client preference in
+	 * rpref
+	 */
+	BUG_ON(spref == NULL);
+	BUG_ON(rpref == NULL);
+
+	/* FIXME sanity check vals */
+
+	/* Are values in any order?  XXX Lame "algorithm" here */
+	for (i = 0; i < slen; i++) {
+		for (j = 0; j < rlen; j++) {
+			if (spref[i] == rpref[j]) {
+				res = &spref[i];
+				break;
+			}
+		}
+		if (res)
+			break;
+	}
+
+	/* we didn't agree on anything */
+	if (res == NULL) {
+		/* confirm previous value */
+		switch (opt->dccpop_feat) {
+		case DCCPF_CCID:
+			/* XXX did i get this right? =P */
+			if (opt->dccpop_type == DCCPO_CHANGE_L)
+				res = &dccp_msk(sk)->dccpms_tx_ccid;
+			else
+				res = &dccp_msk(sk)->dccpms_rx_ccid;
+			break;
+
+		default:
+			DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat);
+			/* XXX implement res */
+			return -EFAULT;
+		}
+
+		dccp_pr_debug("Don't agree... reconfirming %d\n", *res);
+		agree = 0; /* this is used for mandatory options... */
+	}
+
+	/* need to put result and our preference list */
+	rlen = 1 + opt->dccpop_len;
+	rpref = kmalloc(rlen, GFP_ATOMIC);
+	if (rpref == NULL)
+		return -ENOMEM;
+
+	*rpref = *res;
+	memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len);
+
+	/* put it in the "confirm queue" */
+	if (opt->dccpop_sc == NULL) {
+		opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC);
+		if (opt->dccpop_sc == NULL) {
+			kfree(rpref);
+			return -ENOMEM;
+		}
+	} else {
+		/* recycle the confirm slot */
+		BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
+		kfree(opt->dccpop_sc->dccpoc_val);
+		dccp_pr_debug("recycling confirm slot\n");
+	}
+	memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc));
+
+	opt->dccpop_sc->dccpoc_val = rpref;
+	opt->dccpop_sc->dccpoc_len = rlen;
+
+	/* update the option on our side [we are about to send the confirm] */
+	rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res);
+	if (rc) {
+		kfree(opt->dccpop_sc->dccpoc_val);
+		kfree(opt->dccpop_sc);
+		opt->dccpop_sc = NULL;
+		return rc;
+	}
+
+	dccp_pr_debug("Will confirm %d\n", *rpref);
+
+	/* say we want to change to X but we just got a confirm X, suppress our
+	 * change
+	 */
+	if (!opt->dccpop_conf) {
+		if (*opt->dccpop_val == *res)
+			opt->dccpop_conf = 1;
+		dccp_pr_debug("won't ask for change of same feature\n");
+	}
+
+	return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */
+}
+
+static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
+{
+	struct dccp_minisock *dmsk = dccp_msk(sk);
+	struct dccp_opt_pend *opt;
+	int rc = 1;
+	u8 t;
+
+	/*
+	 * We received a CHANGE.  We gotta match it against our own preference
+	 * list.  If we got a CHANGE_R it means it's a change for us, so we need
+	 * to compare our CHANGE_L list.
+	 */
+	if (type == DCCPO_CHANGE_L)
+		t = DCCPO_CHANGE_R;
+	else
+		t = DCCPO_CHANGE_L;
+
+	/* find our preference list for this feature */
+	list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
+		if (opt->dccpop_type != t || opt->dccpop_feat != feature)
+			continue;
+
+		/* find the winner from the two preference lists */
+		rc = dccp_feat_reconcile(sk, opt, val, len);
+		break;
+	}
+
+	/* We didn't deal with the change.  This can happen if we have no
+	 * preference list for the feature.  In fact, it just shouldn't
+	 * happen---if we understand a feature, we should have a preference list
+	 * with at least the default value.
+	 */
+	BUG_ON(rc == 1);
+
+	return rc;
+}
+
+static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
+{
+	struct dccp_opt_pend *opt;
+	struct dccp_minisock *dmsk = dccp_msk(sk);
+	u8 *copy;
+	int rc;
+
+	/* NN features must be Change L (sec. 6.3.2) */
+	if (type != DCCPO_CHANGE_L) {
+		dccp_pr_debug("received %s for NN feature %d\n",
+				dccp_feat_typename(type), feature);
+		return -EFAULT;
+	}
+
+	/* XXX sanity check opt val */
+
+	/* copy option so we can confirm it */
+	opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
+	if (opt == NULL)
+		return -ENOMEM;
+
+	copy = kmemdup(val, len, GFP_ATOMIC);
+	if (copy == NULL) {
+		kfree(opt);
+		return -ENOMEM;
+	}
+
+	opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */
+	opt->dccpop_feat = feature;
+	opt->dccpop_val	 = copy;
+	opt->dccpop_len	 = len;
+
+	/* change feature */
+	rc = dccp_feat_update(sk, type, feature, *val);
+	if (rc) {
+		kfree(opt->dccpop_val);
+		kfree(opt);
+		return rc;
+	}
+
+	dccp_feat_debug(type, feature, *copy);
+
+	list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
+
+	return 0;
+}
+
+static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
+				    u8 type, u8 feature)
+{
+	/* XXX check if other confirms for that are queued and recycle slot */
+	struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
+
+	if (opt == NULL) {
+		/* XXX what do we do?  Ignoring should be fine.  It's a change
+		 * after all =P
+		 */
+		return;
+	}
+
+	switch (type) {
+	case DCCPO_CHANGE_L:
+		opt->dccpop_type = DCCPO_CONFIRM_R;
+		break;
+	case DCCPO_CHANGE_R:
+		opt->dccpop_type = DCCPO_CONFIRM_L;
+		break;
+	default:
+		DCCP_WARN("invalid type %d\n", type);
+		kfree(opt);
+		return;
+	}
+	opt->dccpop_feat = feature;
+	opt->dccpop_val	 = NULL;
+	opt->dccpop_len	 = 0;
+
+	/* change feature */
+	dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);
+
+	list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
+}
+
+static void dccp_feat_flush_confirm(struct sock *sk)
+{
+	struct dccp_minisock *dmsk = dccp_msk(sk);
+	/* Check if there is anything to confirm in the first place */
+	int yes = !list_empty(&dmsk->dccpms_conf);
+
+	if (!yes) {
+		struct dccp_opt_pend *opt;
+
+		list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
+			if (opt->dccpop_conf) {
+				yes = 1;
+				break;
+			}
+		}
+	}
+
+	if (!yes)
+		return;
+
+	/* OK there is something to confirm... */
+	/* XXX check if packet is in flight?  Send delayed ack?? */
+	if (sk->sk_state == DCCP_OPEN)
+		dccp_send_ack(sk);
+}
+
+int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
+{
+	int rc;
+
+	dccp_feat_debug(type, feature, *val);
+
+	/* figure out if it's SP or NN feature */
+	switch (feature) {
+	/* deal with SP features */
+	case DCCPF_CCID:
+		rc = dccp_feat_sp(sk, type, feature, val, len);
+		break;
+
+	/* deal with NN features */
+	case DCCPF_ACK_RATIO:
+		rc = dccp_feat_nn(sk, type, feature, val, len);
+		break;
+
+	/* XXX implement other features */
+	default:
+		dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
+			      dccp_feat_typename(type), feature);
+		rc = -EFAULT;
+		break;
+	}
+
+	/* check if there were problems changing features */
+	if (rc) {
+		/* If we don't agree on SP, we sent a confirm for old value.
+		 * However we propagate rc to caller in case option was
+		 * mandatory
+		 */
+		if (rc != DCCP_FEAT_SP_NOAGREE)
+			dccp_feat_empty_confirm(dccp_msk(sk), type, feature);
+	}
+
+	/* generate the confirm [if required] */
+	dccp_feat_flush_confirm(sk);
+
+	return rc;
+}
+
+EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
+
+int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
+			   u8 *val, u8 len)
+{
+	u8 t;
+	struct dccp_opt_pend *opt;
+	struct dccp_minisock *dmsk = dccp_msk(sk);
+	int found = 0;
+	int all_confirmed = 1;
+
+	dccp_feat_debug(type, feature, *val);
+
+	/* locate our change request */
+	switch (type) {
+	case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
+	case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
+	default:	      DCCP_WARN("invalid type %d\n", type);
+			      return 1;
+
+	}
+	/* XXX sanity check feature value */
+
+	list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
+		if (!opt->dccpop_conf && opt->dccpop_type == t &&
+		    opt->dccpop_feat == feature) {
+			found = 1;
+			dccp_pr_debug("feature %d found\n", opt->dccpop_feat);
+
+			/* XXX do sanity check */
+
+			opt->dccpop_conf = 1;
+
+			/* We got a confirmation---change the option */
+			dccp_feat_update(sk, opt->dccpop_type,
+					 opt->dccpop_feat, *val);
+
+			/* XXX check the return value of dccp_feat_update */
+			break;
+		}
+
+		if (!opt->dccpop_conf)
+			all_confirmed = 0;
+	}
+
+	/* fix re-transmit timer */
+	/* XXX gotta make sure that no option negotiation occurs during
+	 * connection shutdown.  Consider that the CLOSEREQ is sent and timer is
+	 * on.  if all options are confirmed it might kill timer which should
+	 * remain alive until close is received.
+	 */
+	if (all_confirmed) {
+		dccp_pr_debug("clear feat negotiation timer %p\n", sk);
+		inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
+	}
+
+	if (!found)
+		dccp_pr_debug("%s(%d, ...) never requested\n",
+			      dccp_feat_typename(type), feature);
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
+
+void dccp_feat_clean(struct dccp_minisock *dmsk)
+{
+	struct dccp_opt_pend *opt, *next;
+
+	list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
+				 dccpop_node) {
+		BUG_ON(opt->dccpop_val == NULL);
+		kfree(opt->dccpop_val);
+
+		if (opt->dccpop_sc != NULL) {
+			BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
+			kfree(opt->dccpop_sc->dccpoc_val);
+			kfree(opt->dccpop_sc);
+		}
+
+		kfree(opt);
+	}
+	INIT_LIST_HEAD(&dmsk->dccpms_pending);
+
+	list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
+		BUG_ON(opt == NULL);
+		if (opt->dccpop_val != NULL)
+			kfree(opt->dccpop_val);
+		kfree(opt);
+	}
+	INIT_LIST_HEAD(&dmsk->dccpms_conf);
+}
+
+EXPORT_SYMBOL_GPL(dccp_feat_clean);
+
+/* this is to be called only when a listening sock creates its child.  It is
+ * assumed by the function---the confirm is not duplicated, but rather it is
+ * "passed on".
+ */
+int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
+{
+	struct dccp_minisock *olddmsk = dccp_msk(oldsk);
+	struct dccp_minisock *newdmsk = dccp_msk(newsk);
+	struct dccp_opt_pend *opt;
+	int rc = 0;
+
+	INIT_LIST_HEAD(&newdmsk->dccpms_pending);
+	INIT_LIST_HEAD(&newdmsk->dccpms_conf);
+
+	list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
+		struct dccp_opt_pend *newopt;
+		/* copy the value of the option */
+		u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC);
+
+		if (val == NULL)
+			goto out_clean;
+
+		newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC);
+		if (newopt == NULL) {
+			kfree(val);
+			goto out_clean;
+		}
+
+		/* insert the option */
+		newopt->dccpop_val = val;
+		list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);
+
+		/* XXX what happens with backlogs and multiple connections at
+		 * once...
+		 */
+		/* the master socket no longer needs to worry about confirms */
+		opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */
+
+		/* reset state for a new socket */
+		opt->dccpop_conf = 0;
+	}
+
+	/* XXX not doing anything about the conf queue */
+
+out:
+	return rc;
+
+out_clean:
+	dccp_feat_clean(newdmsk);
+	rc = -ENOMEM;
+	goto out;
+}
+
+EXPORT_SYMBOL_GPL(dccp_feat_clone);
+
+static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat,
+			    u8 *val, u8 len)
+{
+	int rc = -ENOMEM;
+	u8 *copy = kmemdup(val, len, GFP_KERNEL);
+
+	if (copy != NULL) {
+		rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL);
+		if (rc)
+			kfree(copy);
+	}
+	return rc;
+}
+
+int dccp_feat_init(struct dccp_minisock *dmsk)
+{
+	int rc;
+
+	INIT_LIST_HEAD(&dmsk->dccpms_pending);
+	INIT_LIST_HEAD(&dmsk->dccpms_conf);
+
+	/* CCID L */
+	rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID,
+			      &dmsk->dccpms_tx_ccid, 1);
+	if (rc)
+		goto out;
+
+	/* CCID R */
+	rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID,
+			      &dmsk->dccpms_rx_ccid, 1);
+	if (rc)
+		goto out;
+
+	/* Ack ratio */
+	rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO,
+			      &dmsk->dccpms_ack_ratio, 1);
+out:
+	return rc;
+}
+
+EXPORT_SYMBOL_GPL(dccp_feat_init);
+
+#ifdef CONFIG_IP_DCCP_DEBUG
+const char *dccp_feat_typename(const u8 type)
+{
+	switch(type) {
+	case DCCPO_CHANGE_L:  return("ChangeL");
+	case DCCPO_CONFIRM_L: return("ConfirmL");
+	case DCCPO_CHANGE_R:  return("ChangeR");
+	case DCCPO_CONFIRM_R: return("ConfirmR");
+	/* the following case must not appear in feature negotation  */
+	default:	      dccp_pr_debug("unknown type %d [BUG!]\n", type);
+	}
+	return NULL;
+}
+
+EXPORT_SYMBOL_GPL(dccp_feat_typename);
+
+const char *dccp_feat_name(const u8 feat)
+{
+	static const char *feature_names[] = {
+		[DCCPF_RESERVED]	= "Reserved",
+		[DCCPF_CCID]		= "CCID",
+		[DCCPF_SHORT_SEQNOS]	= "Allow Short Seqnos",
+		[DCCPF_SEQUENCE_WINDOW]	= "Sequence Window",
+		[DCCPF_ECN_INCAPABLE]	= "ECN Incapable",
+		[DCCPF_ACK_RATIO]	= "Ack Ratio",
+		[DCCPF_SEND_ACK_VECTOR]	= "Send ACK Vector",
+		[DCCPF_SEND_NDP_COUNT]	= "Send NDP Count",
+		[DCCPF_MIN_CSUM_COVER]	= "Min. Csum Coverage",
+		[DCCPF_DATA_CHECKSUM]	= "Send Data Checksum",
+	};
+	if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC)
+		return feature_names[DCCPF_RESERVED];
+
+	if (feat >= DCCPF_MIN_CCID_SPECIFIC)
+		return "CCID-specific";
+
+	return feature_names[feat];
+}
+
+EXPORT_SYMBOL_GPL(dccp_feat_name);
+#endif /* CONFIG_IP_DCCP_DEBUG */
diff --git a/net/dccp/feat.h b/net/dccp/feat.h
new file mode 100644
index 0000000..e272222
--- /dev/null
+++ b/net/dccp/feat.h
@@ -0,0 +1,40 @@
+#ifndef _DCCP_FEAT_H
+#define _DCCP_FEAT_H
+/*
+ *  net/dccp/feat.h
+ *
+ *  An implementation of the DCCP protocol
+ *  Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
+ *
+ *	This program is free software; you can redistribute it and/or modify it
+ *	under the terms of the GNU General Public License version 2 as
+ *	published by the Free Software Foundation.
+ */
+
+#include <linux/types.h>
+#include "dccp.h"
+
+#ifdef CONFIG_IP_DCCP_DEBUG
+extern const char *dccp_feat_typename(const u8 type);
+extern const char *dccp_feat_name(const u8 feat);
+
+static inline void dccp_feat_debug(const u8 type, const u8 feat, const u8 val)
+{
+	dccp_pr_debug("%s(%s (%d), %d)\n", dccp_feat_typename(type),
+					   dccp_feat_name(feat), feat, val);
+}
+#else
+#define dccp_feat_debug(type, feat, val)
+#endif /* CONFIG_IP_DCCP_DEBUG */
+
+extern int  dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
+			     u8 *val, u8 len, gfp_t gfp);
+extern int  dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature,
+				  u8 *val, u8 len);
+extern int  dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
+				   u8 *val, u8 len);
+extern void dccp_feat_clean(struct dccp_minisock *dmsk);
+extern int  dccp_feat_clone(struct sock *oldsk, struct sock *newsk);
+extern int  dccp_feat_init(struct dccp_minisock *dmsk);
+
+#endif /* _DCCP_FEAT_H */
diff --git a/net/dccp/input.c b/net/dccp/input.c
new file mode 100644
index 0000000..779d0ed
--- /dev/null
+++ b/net/dccp/input.c
@@ -0,0 +1,731 @@
+/*
+ *  net/dccp/input.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/dccp.h>
+#include <linux/skbuff.h>
+
+#include <net/sock.h>
+
+#include "ackvec.h"
+#include "ccid.h"
+#include "dccp.h"
+
+/* rate-limit for syncs in reply to sequence-invalid packets; RFC 4340, 7.5.4 */
+int sysctl_dccp_sync_ratelimit	__read_mostly = HZ / 8;
+
+static void dccp_enqueue_skb(struct sock *sk, struct sk_buff *skb)
+{
+	__skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4);
+	__skb_queue_tail(&sk->sk_receive_queue, skb);
+	skb_set_owner_r(skb, sk);
+	sk->sk_data_ready(sk, 0);
+}
+
+static void dccp_fin(struct sock *sk, struct sk_buff *skb)
+{
+	/*
+	 * On receiving Close/CloseReq, both RD/WR shutdown are performed.
+	 * RFC 4340, 8.3 says that we MAY send further Data/DataAcks after
+	 * receiving the closing segment, but there is no guarantee that such
+	 * data will be processed at all.
+	 */
+	sk->sk_shutdown = SHUTDOWN_MASK;
+	sock_set_flag(sk, SOCK_DONE);
+	dccp_enqueue_skb(sk, skb);
+}
+
+static int dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
+{
+	int queued = 0;
+
+	switch (sk->sk_state) {
+	/*
+	 * We ignore Close when received in one of the following states:
+	 *  - CLOSED		(may be a late or duplicate packet)
+	 *  - PASSIVE_CLOSEREQ	(the peer has sent a CloseReq earlier)
+	 *  - RESPOND		(already handled by dccp_check_req)
+	 */
+	case DCCP_CLOSING:
+		/*
+		 * Simultaneous-close: receiving a Close after sending one. This
+		 * can happen if both client and server perform active-close and
+		 * will result in an endless ping-pong of crossing and retrans-
+		 * mitted Close packets, which only terminates when one of the
+		 * nodes times out (min. 64 seconds). Quicker convergence can be
+		 * achieved when one of the nodes acts as tie-breaker.
+		 * This is ok as both ends are done with data transfer and each
+		 * end is just waiting for the other to acknowledge termination.
+		 */
+		if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT)
+			break;
+		/* fall through */
+	case DCCP_REQUESTING:
+	case DCCP_ACTIVE_CLOSEREQ:
+		dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED);
+		dccp_done(sk);
+		break;
+	case DCCP_OPEN:
+	case DCCP_PARTOPEN:
+		/* Give waiting application a chance to read pending data */
+		queued = 1;
+		dccp_fin(sk, skb);
+		dccp_set_state(sk, DCCP_PASSIVE_CLOSE);
+		/* fall through */
+	case DCCP_PASSIVE_CLOSE:
+		/*
+		 * Retransmitted Close: we have already enqueued the first one.
+		 */
+		sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
+	}
+	return queued;
+}
+
+static int dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
+{
+	int queued = 0;
+
+	/*
+	 *   Step 7: Check for unexpected packet types
+	 *      If (S.is_server and P.type == CloseReq)
+	 *	  Send Sync packet acknowledging P.seqno
+	 *	  Drop packet and return
+	 */
+	if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {
+		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
+		return queued;
+	}
+
+	/* Step 13: process relevant Client states < CLOSEREQ */
+	switch (sk->sk_state) {
+	case DCCP_REQUESTING:
+		dccp_send_close(sk, 0);
+		dccp_set_state(sk, DCCP_CLOSING);
+		break;
+	case DCCP_OPEN:
+	case DCCP_PARTOPEN:
+		/* Give waiting application a chance to read pending data */
+		queued = 1;
+		dccp_fin(sk, skb);
+		dccp_set_state(sk, DCCP_PASSIVE_CLOSEREQ);
+		/* fall through */
+	case DCCP_PASSIVE_CLOSEREQ:
+		sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP);
+	}
+	return queued;
+}
+
+static u8 dccp_reset_code_convert(const u8 code)
+{
+	const u8 error_code[] = {
+	[DCCP_RESET_CODE_CLOSED]	     = 0,	/* normal termination */
+	[DCCP_RESET_CODE_UNSPECIFIED]	     = 0,	/* nothing known */
+	[DCCP_RESET_CODE_ABORTED]	     = ECONNRESET,
+
+	[DCCP_RESET_CODE_NO_CONNECTION]	     = ECONNREFUSED,
+	[DCCP_RESET_CODE_CONNECTION_REFUSED] = ECONNREFUSED,
+	[DCCP_RESET_CODE_TOO_BUSY]	     = EUSERS,
+	[DCCP_RESET_CODE_AGGRESSION_PENALTY] = EDQUOT,
+
+	[DCCP_RESET_CODE_PACKET_ERROR]	     = ENOMSG,
+	[DCCP_RESET_CODE_BAD_INIT_COOKIE]    = EBADR,
+	[DCCP_RESET_CODE_BAD_SERVICE_CODE]   = EBADRQC,
+	[DCCP_RESET_CODE_OPTION_ERROR]	     = EILSEQ,
+	[DCCP_RESET_CODE_MANDATORY_ERROR]    = EOPNOTSUPP,
+	};
+
+	return code >= DCCP_MAX_RESET_CODES ? 0 : error_code[code];
+}
+
+static void dccp_rcv_reset(struct sock *sk, struct sk_buff *skb)
+{
+	u8 err = dccp_reset_code_convert(dccp_hdr_reset(skb)->dccph_reset_code);
+
+	sk->sk_err = err;
+
+	/* Queue the equivalent of TCP fin so that dccp_recvmsg exits the loop */
+	dccp_fin(sk, skb);
+
+	if (err && !sock_flag(sk, SOCK_DEAD))
+		sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR);
+	dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
+}
+
+static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+
+	if (dccp_msk(sk)->dccpms_send_ack_vector)
+		dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
+					    DCCP_SKB_CB(skb)->dccpd_ack_seq);
+}
+
+static void dccp_deliver_input_to_ccids(struct sock *sk, struct sk_buff *skb)
+{
+	const struct dccp_sock *dp = dccp_sk(sk);
+
+	/* Don't deliver to RX CCID when node has shut down read end. */
+	if (!(sk->sk_shutdown & RCV_SHUTDOWN))
+		ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
+	/*
+	 * Until the TX queue has been drained, we can not honour SHUT_WR, since
+	 * we need received feedback as input to adjust congestion control.
+	 */
+	if (sk->sk_write_queue.qlen > 0 || !(sk->sk_shutdown & SEND_SHUTDOWN))
+		ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
+}
+
+static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh = dccp_hdr(skb);
+	struct dccp_sock *dp = dccp_sk(sk);
+	u64 lswl, lawl, seqno = DCCP_SKB_CB(skb)->dccpd_seq,
+			ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
+
+	/*
+	 *   Step 5: Prepare sequence numbers for Sync
+	 *     If P.type == Sync or P.type == SyncAck,
+	 *	  If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
+	 *	     / * P is valid, so update sequence number variables
+	 *		 accordingly.  After this update, P will pass the tests
+	 *		 in Step 6.  A SyncAck is generated if necessary in
+	 *		 Step 15 * /
+	 *	     Update S.GSR, S.SWL, S.SWH
+	 *	  Otherwise,
+	 *	     Drop packet and return
+	 */
+	if (dh->dccph_type == DCCP_PKT_SYNC ||
+	    dh->dccph_type == DCCP_PKT_SYNCACK) {
+		if (between48(ackno, dp->dccps_awl, dp->dccps_awh) &&
+		    dccp_delta_seqno(dp->dccps_swl, seqno) >= 0)
+			dccp_update_gsr(sk, seqno);
+		else
+			return -1;
+	}
+
+	/*
+	 *   Step 6: Check sequence numbers
+	 *      Let LSWL = S.SWL and LAWL = S.AWL
+	 *      If P.type == CloseReq or P.type == Close or P.type == Reset,
+	 *	  LSWL := S.GSR + 1, LAWL := S.GAR
+	 *      If LSWL <= P.seqno <= S.SWH
+	 *	     and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
+	 *	  Update S.GSR, S.SWL, S.SWH
+	 *	  If P.type != Sync,
+	 *	     Update S.GAR
+	 */
+	lswl = dp->dccps_swl;
+	lawl = dp->dccps_awl;
+
+	if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
+	    dh->dccph_type == DCCP_PKT_CLOSE ||
+	    dh->dccph_type == DCCP_PKT_RESET) {
+		lswl = ADD48(dp->dccps_gsr, 1);
+		lawl = dp->dccps_gar;
+	}
+
+	if (between48(seqno, lswl, dp->dccps_swh) &&
+	    (ackno == DCCP_PKT_WITHOUT_ACK_SEQ ||
+	     between48(ackno, lawl, dp->dccps_awh))) {
+		dccp_update_gsr(sk, seqno);
+
+		if (dh->dccph_type != DCCP_PKT_SYNC &&
+		    (ackno != DCCP_PKT_WITHOUT_ACK_SEQ))
+			dp->dccps_gar = ackno;
+	} else {
+		unsigned long now = jiffies;
+		/*
+		 *   Step 6: Check sequence numbers
+		 *      Otherwise,
+		 *         If P.type == Reset,
+		 *            Send Sync packet acknowledging S.GSR
+		 *         Otherwise,
+		 *            Send Sync packet acknowledging P.seqno
+		 *      Drop packet and return
+		 *
+		 *   These Syncs are rate-limited as per RFC 4340, 7.5.4:
+		 *   at most 1 / (dccp_sync_rate_limit * HZ) Syncs per second.
+		 */
+		if (time_before(now, (dp->dccps_rate_last +
+				      sysctl_dccp_sync_ratelimit)))
+			return 0;
+
+		DCCP_WARN("DCCP: Step 6 failed for %s packet, "
+			  "(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
+			  "(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
+			  "sending SYNC...\n",  dccp_packet_name(dh->dccph_type),
+			  (unsigned long long) lswl, (unsigned long long) seqno,
+			  (unsigned long long) dp->dccps_swh,
+			  (ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist"
+							      : "exists",
+			  (unsigned long long) lawl, (unsigned long long) ackno,
+			  (unsigned long long) dp->dccps_awh);
+
+		dp->dccps_rate_last = now;
+
+		if (dh->dccph_type == DCCP_PKT_RESET)
+			seqno = dp->dccps_gsr;
+		dccp_send_sync(sk, seqno, DCCP_PKT_SYNC);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
+				  const struct dccp_hdr *dh, const unsigned len)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+
+	switch (dccp_hdr(skb)->dccph_type) {
+	case DCCP_PKT_DATAACK:
+	case DCCP_PKT_DATA:
+		/*
+		 * FIXME: schedule DATA_DROPPED (RFC 4340, 11.7.2) if and when
+		 * - sk_shutdown == RCV_SHUTDOWN, use Code 1, "Not Listening"
+		 * - sk_receive_queue is full, use Code 2, "Receive Buffer"
+		 */
+		dccp_enqueue_skb(sk, skb);
+		return 0;
+	case DCCP_PKT_ACK:
+		goto discard;
+	case DCCP_PKT_RESET:
+		/*
+		 *  Step 9: Process Reset
+		 *	If P.type == Reset,
+		 *		Tear down connection
+		 *		S.state := TIMEWAIT
+		 *		Set TIMEWAIT timer
+		 *		Drop packet and return
+		 */
+		dccp_rcv_reset(sk, skb);
+		return 0;
+	case DCCP_PKT_CLOSEREQ:
+		if (dccp_rcv_closereq(sk, skb))
+			return 0;
+		goto discard;
+	case DCCP_PKT_CLOSE:
+		if (dccp_rcv_close(sk, skb))
+			return 0;
+		goto discard;
+	case DCCP_PKT_REQUEST:
+		/* Step 7
+		 *   or (S.is_server and P.type == Response)
+		 *   or (S.is_client and P.type == Request)
+		 *   or (S.state >= OPEN and P.type == Request
+		 *	and P.seqno >= S.OSR)
+		 *    or (S.state >= OPEN and P.type == Response
+		 *	and P.seqno >= S.OSR)
+		 *    or (S.state == RESPOND and P.type == Data),
+		 *  Send Sync packet acknowledging P.seqno
+		 *  Drop packet and return
+		 */
+		if (dp->dccps_role != DCCP_ROLE_LISTEN)
+			goto send_sync;
+		goto check_seq;
+	case DCCP_PKT_RESPONSE:
+		if (dp->dccps_role != DCCP_ROLE_CLIENT)
+			goto send_sync;
+check_seq:
+		if (dccp_delta_seqno(dp->dccps_osr,
+				     DCCP_SKB_CB(skb)->dccpd_seq) >= 0) {
+send_sync:
+			dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
+				       DCCP_PKT_SYNC);
+		}
+		break;
+	case DCCP_PKT_SYNC:
+		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
+			       DCCP_PKT_SYNCACK);
+		/*
+		 * From RFC 4340, sec. 5.7
+		 *
+		 * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
+		 * MAY have non-zero-length application data areas, whose
+		 * contents receivers MUST ignore.
+		 */
+		goto discard;
+	}
+
+	DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
+discard:
+	__kfree_skb(skb);
+	return 0;
+}
+
+int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
+			 const struct dccp_hdr *dh, const unsigned len)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+
+	if (dccp_check_seqno(sk, skb))
+		goto discard;
+
+	if (dccp_parse_options(sk, NULL, skb))
+		return 1;
+
+	if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
+		dccp_event_ack_recv(sk, skb);
+
+	if (dccp_msk(sk)->dccpms_send_ack_vector &&
+	    dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
+			    DCCP_SKB_CB(skb)->dccpd_seq,
+			    DCCP_ACKVEC_STATE_RECEIVED))
+		goto discard;
+	dccp_deliver_input_to_ccids(sk, skb);
+
+	return __dccp_rcv_established(sk, skb, dh, len);
+discard:
+	__kfree_skb(skb);
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_rcv_established);
+
+static int dccp_rcv_request_sent_state_process(struct sock *sk,
+					       struct sk_buff *skb,
+					       const struct dccp_hdr *dh,
+					       const unsigned len)
+{
+	/*
+	 *  Step 4: Prepare sequence numbers in REQUEST
+	 *     If S.state == REQUEST,
+	 *	  If (P.type == Response or P.type == Reset)
+	 *		and S.AWL <= P.ackno <= S.AWH,
+	 *	     / * Set sequence number variables corresponding to the
+	 *		other endpoint, so P will pass the tests in Step 6 * /
+	 *	     Set S.GSR, S.ISR, S.SWL, S.SWH
+	 *	     / * Response processing continues in Step 10; Reset
+	 *		processing continues in Step 9 * /
+	*/
+	if (dh->dccph_type == DCCP_PKT_RESPONSE) {
+		const struct inet_connection_sock *icsk = inet_csk(sk);
+		struct dccp_sock *dp = dccp_sk(sk);
+		long tstamp = dccp_timestamp();
+
+		if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
+			       dp->dccps_awl, dp->dccps_awh)) {
+			dccp_pr_debug("invalid ackno: S.AWL=%llu, "
+				      "P.ackno=%llu, S.AWH=%llu \n",
+				      (unsigned long long)dp->dccps_awl,
+			   (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
+				      (unsigned long long)dp->dccps_awh);
+			goto out_invalid_packet;
+		}
+
+		if (dccp_parse_options(sk, NULL, skb))
+			goto out_invalid_packet;
+
+		/* Obtain usec RTT sample from SYN exchange (used by CCID 3) */
+		if (likely(dp->dccps_options_received.dccpor_timestamp_echo))
+			dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp -
+			    dp->dccps_options_received.dccpor_timestamp_echo));
+
+		if (dccp_msk(sk)->dccpms_send_ack_vector &&
+		    dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
+				    DCCP_SKB_CB(skb)->dccpd_seq,
+				    DCCP_ACKVEC_STATE_RECEIVED))
+			goto out_invalid_packet; /* FIXME: change error code */
+
+		/* Stop the REQUEST timer */
+		inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
+		WARN_ON(sk->sk_send_head == NULL);
+		kfree_skb(sk->sk_send_head);
+		sk->sk_send_head = NULL;
+
+		dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
+		dccp_update_gsr(sk, dp->dccps_isr);
+		/*
+		 * SWL and AWL are initially adjusted so that they are not less than
+		 * the initial Sequence Numbers received and sent, respectively:
+		 *	SWL := max(GSR + 1 - floor(W/4), ISR),
+		 *	AWL := max(GSS - W' + 1, ISS).
+		 * These adjustments MUST be applied only at the beginning of the
+		 * connection.
+		 *
+		 * AWL was adjusted in dccp_v4_connect -acme
+		 */
+		dccp_set_seqno(&dp->dccps_swl,
+			       max48(dp->dccps_swl, dp->dccps_isr));
+
+		dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
+
+		/*
+		 *    Step 10: Process REQUEST state (second part)
+		 *       If S.state == REQUEST,
+		 *	  / * If we get here, P is a valid Response from the
+		 *	      server (see Step 4), and we should move to
+		 *	      PARTOPEN state. PARTOPEN means send an Ack,
+		 *	      don't send Data packets, retransmit Acks
+		 *	      periodically, and always include any Init Cookie
+		 *	      from the Response * /
+		 *	  S.state := PARTOPEN
+		 *	  Set PARTOPEN timer
+		 *	  Continue with S.state == PARTOPEN
+		 *	  / * Step 12 will send the Ack completing the
+		 *	      three-way handshake * /
+		 */
+		dccp_set_state(sk, DCCP_PARTOPEN);
+
+		/* Make sure socket is routed, for correct metrics. */
+		icsk->icsk_af_ops->rebuild_header(sk);
+
+		if (!sock_flag(sk, SOCK_DEAD)) {
+			sk->sk_state_change(sk);
+			sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
+		}
+
+		if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
+		    icsk->icsk_accept_queue.rskq_defer_accept) {
+			/* Save one ACK. Data will be ready after
+			 * several ticks, if write_pending is set.
+			 *
+			 * It may be deleted, but with this feature tcpdumps
+			 * look so _wonderfully_ clever, that I was not able
+			 * to stand against the temptation 8)     --ANK
+			 */
+			/*
+			 * OK, in DCCP we can as well do a similar trick, its
+			 * even in the draft, but there is no need for us to
+			 * schedule an ack here, as dccp_sendmsg does this for
+			 * us, also stated in the draft. -acme
+			 */
+			__kfree_skb(skb);
+			return 0;
+		}
+		dccp_send_ack(sk);
+		return -1;
+	}
+
+out_invalid_packet:
+	/* dccp_v4_do_rcv will send a reset */
+	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
+	return 1;
+}
+
+static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
+						   struct sk_buff *skb,
+						   const struct dccp_hdr *dh,
+						   const unsigned len)
+{
+	int queued = 0;
+
+	switch (dh->dccph_type) {
+	case DCCP_PKT_RESET:
+		inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
+		break;
+	case DCCP_PKT_DATA:
+		if (sk->sk_state == DCCP_RESPOND)
+			break;
+	case DCCP_PKT_DATAACK:
+	case DCCP_PKT_ACK:
+		/*
+		 * FIXME: we should be reseting the PARTOPEN (DELACK) timer
+		 * here but only if we haven't used the DELACK timer for
+		 * something else, like sending a delayed ack for a TIMESTAMP
+		 * echo, etc, for now were not clearing it, sending an extra
+		 * ACK when there is nothing else to do in DELACK is not a big
+		 * deal after all.
+		 */
+
+		/* Stop the PARTOPEN timer */
+		if (sk->sk_state == DCCP_PARTOPEN)
+			inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
+
+		dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
+		dccp_set_state(sk, DCCP_OPEN);
+
+		if (dh->dccph_type == DCCP_PKT_DATAACK ||
+		    dh->dccph_type == DCCP_PKT_DATA) {
+			__dccp_rcv_established(sk, skb, dh, len);
+			queued = 1; /* packet was queued
+				       (by __dccp_rcv_established) */
+		}
+		break;
+	}
+
+	return queued;
+}
+
+int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
+			   struct dccp_hdr *dh, unsigned len)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
+	const int old_state = sk->sk_state;
+	int queued = 0;
+
+	/*
+	 *  Step 3: Process LISTEN state
+	 *
+	 *     If S.state == LISTEN,
+	 *	 If P.type == Request or P contains a valid Init Cookie option,
+	 *	      (* Must scan the packet's options to check for Init
+	 *		 Cookies.  Only Init Cookies are processed here,
+	 *		 however; other options are processed in Step 8.  This
+	 *		 scan need only be performed if the endpoint uses Init
+	 *		 Cookies *)
+	 *	      (* Generate a new socket and switch to that socket *)
+	 *	      Set S := new socket for this port pair
+	 *	      S.state = RESPOND
+	 *	      Choose S.ISS (initial seqno) or set from Init Cookies
+	 *	      Initialize S.GAR := S.ISS
+	 *	      Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init
+	 *	      Cookies Continue with S.state == RESPOND
+	 *	      (* A Response packet will be generated in Step 11 *)
+	 *	 Otherwise,
+	 *	      Generate Reset(No Connection) unless P.type == Reset
+	 *	      Drop packet and return
+	 */
+	if (sk->sk_state == DCCP_LISTEN) {
+		if (dh->dccph_type == DCCP_PKT_REQUEST) {
+			if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
+								    skb) < 0)
+				return 1;
+
+			/* FIXME: do congestion control initialization */
+			goto discard;
+		}
+		if (dh->dccph_type == DCCP_PKT_RESET)
+			goto discard;
+
+		/* Caller (dccp_v4_do_rcv) will send Reset */
+		dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
+		return 1;
+	}
+
+	if (sk->sk_state != DCCP_REQUESTING) {
+		if (dccp_check_seqno(sk, skb))
+			goto discard;
+
+		/*
+		 * Step 8: Process options and mark acknowledgeable
+		 */
+		if (dccp_parse_options(sk, NULL, skb))
+			return 1;
+
+		if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
+			dccp_event_ack_recv(sk, skb);
+
+		if (dccp_msk(sk)->dccpms_send_ack_vector &&
+		    dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
+				    DCCP_SKB_CB(skb)->dccpd_seq,
+				    DCCP_ACKVEC_STATE_RECEIVED))
+			goto discard;
+
+		dccp_deliver_input_to_ccids(sk, skb);
+	}
+
+	/*
+	 *  Step 9: Process Reset
+	 *	If P.type == Reset,
+	 *		Tear down connection
+	 *		S.state := TIMEWAIT
+	 *		Set TIMEWAIT timer
+	 *		Drop packet and return
+	*/
+	if (dh->dccph_type == DCCP_PKT_RESET) {
+		dccp_rcv_reset(sk, skb);
+		return 0;
+		/*
+		 *   Step 7: Check for unexpected packet types
+		 *      If (S.is_server and P.type == Response)
+		 *	    or (S.is_client and P.type == Request)
+		 *	    or (S.state == RESPOND and P.type == Data),
+		 *	  Send Sync packet acknowledging P.seqno
+		 *	  Drop packet and return
+		 */
+	} else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
+		    dh->dccph_type == DCCP_PKT_RESPONSE) ||
+		    (dp->dccps_role == DCCP_ROLE_CLIENT &&
+		     dh->dccph_type == DCCP_PKT_REQUEST) ||
+		    (sk->sk_state == DCCP_RESPOND &&
+		     dh->dccph_type == DCCP_PKT_DATA)) {
+		dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
+		goto discard;
+	} else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
+		if (dccp_rcv_closereq(sk, skb))
+			return 0;
+		goto discard;
+	} else if (dh->dccph_type == DCCP_PKT_CLOSE) {
+		if (dccp_rcv_close(sk, skb))
+			return 0;
+		goto discard;
+	}
+
+	switch (sk->sk_state) {
+	case DCCP_CLOSED:
+		dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
+		return 1;
+
+	case DCCP_REQUESTING:
+		/* FIXME: do congestion control initialization */
+
+		queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
+		if (queued >= 0)
+			return queued;
+
+		__kfree_skb(skb);
+		return 0;
+
+	case DCCP_RESPOND:
+	case DCCP_PARTOPEN:
+		queued = dccp_rcv_respond_partopen_state_process(sk, skb,
+								 dh, len);
+		break;
+	}
+
+	if (dh->dccph_type == DCCP_PKT_ACK ||
+	    dh->dccph_type == DCCP_PKT_DATAACK) {
+		switch (old_state) {
+		case DCCP_PARTOPEN:
+			sk->sk_state_change(sk);
+			sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);
+			break;
+		}
+	} else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
+		dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
+		goto discard;
+	}
+
+	if (!queued) {
+discard:
+		__kfree_skb(skb);
+	}
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_rcv_state_process);
+
+/**
+ *  dccp_sample_rtt  -  Validate and finalise computation of RTT sample
+ *  @delta:	number of microseconds between packet and acknowledgment
+ *  The routine is kept generic to work in different contexts. It should be
+ *  called immediately when the ACK used for the RTT sample arrives.
+ */
+u32 dccp_sample_rtt(struct sock *sk, long delta)
+{
+	/* dccpor_elapsed_time is either zeroed out or set and > 0 */
+	delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10;
+
+	if (unlikely(delta <= 0)) {
+		DCCP_WARN("unusable RTT sample %ld, using min\n", delta);
+		return DCCP_SANE_RTT_MIN;
+	}
+	if (unlikely(delta > DCCP_SANE_RTT_MAX)) {
+		DCCP_WARN("RTT sample %ld too large, using max\n", delta);
+		return DCCP_SANE_RTT_MAX;
+	}
+
+	return delta;
+}
+
+EXPORT_SYMBOL_GPL(dccp_sample_rtt);
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
new file mode 100644
index 0000000..e3dfdda
--- /dev/null
+++ b/net/dccp/ipv4.c
@@ -0,0 +1,1059 @@
+/*
+ *  net/dccp/ipv4.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/dccp.h>
+#include <linux/icmp.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/random.h>
+
+#include <net/icmp.h>
+#include <net/inet_common.h>
+#include <net/inet_hashtables.h>
+#include <net/inet_sock.h>
+#include <net/protocol.h>
+#include <net/sock.h>
+#include <net/timewait_sock.h>
+#include <net/tcp_states.h>
+#include <net/xfrm.h>
+
+#include "ackvec.h"
+#include "ccid.h"
+#include "dccp.h"
+#include "feat.h"
+
+/*
+ * The per-net dccp.v4_ctl_sk socket is used for responding to
+ * the Out-of-the-blue (OOTB) packets. A control sock will be created
+ * for this socket at the initialization time.
+ */
+
+int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
+{
+	struct inet_sock *inet = inet_sk(sk);
+	struct dccp_sock *dp = dccp_sk(sk);
+	const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
+	struct rtable *rt;
+	__be32 daddr, nexthop;
+	int tmp;
+	int err;
+
+	dp->dccps_role = DCCP_ROLE_CLIENT;
+
+	if (addr_len < sizeof(struct sockaddr_in))
+		return -EINVAL;
+
+	if (usin->sin_family != AF_INET)
+		return -EAFNOSUPPORT;
+
+	nexthop = daddr = usin->sin_addr.s_addr;
+	if (inet->opt != NULL && inet->opt->srr) {
+		if (daddr == 0)
+			return -EINVAL;
+		nexthop = inet->opt->faddr;
+	}
+
+	tmp = ip_route_connect(&rt, nexthop, inet->saddr,
+			       RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
+			       IPPROTO_DCCP,
+			       inet->sport, usin->sin_port, sk, 1);
+	if (tmp < 0)
+		return tmp;
+
+	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
+		ip_rt_put(rt);
+		return -ENETUNREACH;
+	}
+
+	if (inet->opt == NULL || !inet->opt->srr)
+		daddr = rt->rt_dst;
+
+	if (inet->saddr == 0)
+		inet->saddr = rt->rt_src;
+	inet->rcv_saddr = inet->saddr;
+
+	inet->dport = usin->sin_port;
+	inet->daddr = daddr;
+
+	inet_csk(sk)->icsk_ext_hdr_len = 0;
+	if (inet->opt != NULL)
+		inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
+	/*
+	 * Socket identity is still unknown (sport may be zero).
+	 * However we set state to DCCP_REQUESTING and not releasing socket
+	 * lock select source port, enter ourselves into the hash tables and
+	 * complete initialization after this.
+	 */
+	dccp_set_state(sk, DCCP_REQUESTING);
+	err = inet_hash_connect(&dccp_death_row, sk);
+	if (err != 0)
+		goto failure;
+
+	err = ip_route_newports(&rt, IPPROTO_DCCP, inet->sport, inet->dport,
+				sk);
+	if (err != 0)
+		goto failure;
+
+	/* OK, now commit destination to socket.  */
+	sk_setup_caps(sk, &rt->u.dst);
+
+	dp->dccps_iss = secure_dccp_sequence_number(inet->saddr, inet->daddr,
+						    inet->sport, inet->dport);
+	inet->id = dp->dccps_iss ^ jiffies;
+
+	err = dccp_connect(sk);
+	rt = NULL;
+	if (err != 0)
+		goto failure;
+out:
+	return err;
+failure:
+	/*
+	 * This unhashes the socket and releases the local port, if necessary.
+	 */
+	dccp_set_state(sk, DCCP_CLOSED);
+	ip_rt_put(rt);
+	sk->sk_route_caps = 0;
+	inet->dport = 0;
+	goto out;
+}
+
+EXPORT_SYMBOL_GPL(dccp_v4_connect);
+
+/*
+ * This routine does path mtu discovery as defined in RFC1191.
+ */
+static inline void dccp_do_pmtu_discovery(struct sock *sk,
+					  const struct iphdr *iph,
+					  u32 mtu)
+{
+	struct dst_entry *dst;
+	const struct inet_sock *inet = inet_sk(sk);
+	const struct dccp_sock *dp = dccp_sk(sk);
+
+	/* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
+	 * send out by Linux are always < 576bytes so they should go through
+	 * unfragmented).
+	 */
+	if (sk->sk_state == DCCP_LISTEN)
+		return;
+
+	/* We don't check in the destentry if pmtu discovery is forbidden
+	 * on this route. We just assume that no packet_to_big packets
+	 * are send back when pmtu discovery is not active.
+	 * There is a small race when the user changes this flag in the
+	 * route, but I think that's acceptable.
+	 */
+	if ((dst = __sk_dst_check(sk, 0)) == NULL)
+		return;
+
+	dst->ops->update_pmtu(dst, mtu);
+
+	/* Something is about to be wrong... Remember soft error
+	 * for the case, if this connection will not able to recover.
+	 */
+	if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
+		sk->sk_err_soft = EMSGSIZE;
+
+	mtu = dst_mtu(dst);
+
+	if (inet->pmtudisc != IP_PMTUDISC_DONT &&
+	    inet_csk(sk)->icsk_pmtu_cookie > mtu) {
+		dccp_sync_mss(sk, mtu);
+
+		/*
+		 * From RFC 4340, sec. 14.1:
+		 *
+		 *	DCCP-Sync packets are the best choice for upward
+		 *	probing, since DCCP-Sync probes do not risk application
+		 *	data loss.
+		 */
+		dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
+	} /* else let the usual retransmit timer handle it */
+}
+
+/*
+ * This routine is called by the ICMP module when it gets some sort of error
+ * condition. If err < 0 then the socket should be closed and the error
+ * returned to the user. If err > 0 it's just the icmp type << 8 | icmp code.
+ * After adjustment header points to the first 8 bytes of the tcp header. We
+ * need to find the appropriate port.
+ *
+ * The locking strategy used here is very "optimistic". When someone else
+ * accesses the socket the ICMP is just dropped and for some paths there is no
+ * check at all. A more general error queue to queue errors for later handling
+ * is probably better.
+ */
+static void dccp_v4_err(struct sk_buff *skb, u32 info)
+{
+	const struct iphdr *iph = (struct iphdr *)skb->data;
+	const u8 offset = iph->ihl << 2;
+	const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
+	struct dccp_sock *dp;
+	struct inet_sock *inet;
+	const int type = icmp_hdr(skb)->type;
+	const int code = icmp_hdr(skb)->code;
+	struct sock *sk;
+	__u64 seq;
+	int err;
+	struct net *net = dev_net(skb->dev);
+
+	if (skb->len < offset + sizeof(*dh) ||
+	    skb->len < offset + __dccp_basic_hdr_len(dh)) {
+		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
+		return;
+	}
+
+	sk = inet_lookup(net, &dccp_hashinfo,
+			iph->daddr, dh->dccph_dport,
+			iph->saddr, dh->dccph_sport, inet_iif(skb));
+	if (sk == NULL) {
+		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
+		return;
+	}
+
+	if (sk->sk_state == DCCP_TIME_WAIT) {
+		inet_twsk_put(inet_twsk(sk));
+		return;
+	}
+
+	bh_lock_sock(sk);
+	/* If too many ICMPs get dropped on busy
+	 * servers this needs to be solved differently.
+	 */
+	if (sock_owned_by_user(sk))
+		NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
+
+	if (sk->sk_state == DCCP_CLOSED)
+		goto out;
+
+	dp = dccp_sk(sk);
+	seq = dccp_hdr_seq(dh);
+	if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
+	    !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
+		NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
+		goto out;
+	}
+
+	switch (type) {
+	case ICMP_SOURCE_QUENCH:
+		/* Just silently ignore these. */
+		goto out;
+	case ICMP_PARAMETERPROB:
+		err = EPROTO;
+		break;
+	case ICMP_DEST_UNREACH:
+		if (code > NR_ICMP_UNREACH)
+			goto out;
+
+		if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
+			if (!sock_owned_by_user(sk))
+				dccp_do_pmtu_discovery(sk, iph, info);
+			goto out;
+		}
+
+		err = icmp_err_convert[code].errno;
+		break;
+	case ICMP_TIME_EXCEEDED:
+		err = EHOSTUNREACH;
+		break;
+	default:
+		goto out;
+	}
+
+	switch (sk->sk_state) {
+		struct request_sock *req , **prev;
+	case DCCP_LISTEN:
+		if (sock_owned_by_user(sk))
+			goto out;
+		req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
+					  iph->daddr, iph->saddr);
+		if (!req)
+			goto out;
+
+		/*
+		 * ICMPs are not backlogged, hence we cannot get an established
+		 * socket here.
+		 */
+		WARN_ON(req->sk);
+
+		if (seq != dccp_rsk(req)->dreq_iss) {
+			NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
+			goto out;
+		}
+		/*
+		 * Still in RESPOND, just remove it silently.
+		 * There is no good way to pass the error to the newly
+		 * created socket, and POSIX does not want network
+		 * errors returned from accept().
+		 */
+		inet_csk_reqsk_queue_drop(sk, req, prev);
+		goto out;
+
+	case DCCP_REQUESTING:
+	case DCCP_RESPOND:
+		if (!sock_owned_by_user(sk)) {
+			DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
+			sk->sk_err = err;
+
+			sk->sk_error_report(sk);
+
+			dccp_done(sk);
+		} else
+			sk->sk_err_soft = err;
+		goto out;
+	}
+
+	/* If we've already connected we will keep trying
+	 * until we time out, or the user gives up.
+	 *
+	 * rfc1122 4.2.3.9 allows to consider as hard errors
+	 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
+	 * but it is obsoleted by pmtu discovery).
+	 *
+	 * Note, that in modern internet, where routing is unreliable
+	 * and in each dark corner broken firewalls sit, sending random
+	 * errors ordered by their masters even this two messages finally lose
+	 * their original sense (even Linux sends invalid PORT_UNREACHs)
+	 *
+	 * Now we are in compliance with RFCs.
+	 *							--ANK (980905)
+	 */
+
+	inet = inet_sk(sk);
+	if (!sock_owned_by_user(sk) && inet->recverr) {
+		sk->sk_err = err;
+		sk->sk_error_report(sk);
+	} else /* Only an error on timeout */
+		sk->sk_err_soft = err;
+out:
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
+
+static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,
+				      __be32 src, __be32 dst)
+{
+	return csum_tcpudp_magic(src, dst, skb->len, IPPROTO_DCCP, skb->csum);
+}
+
+void dccp_v4_send_check(struct sock *sk, int unused, struct sk_buff *skb)
+{
+	const struct inet_sock *inet = inet_sk(sk);
+	struct dccp_hdr *dh = dccp_hdr(skb);
+
+	dccp_csum_outgoing(skb);
+	dh->dccph_checksum = dccp_v4_csum_finish(skb, inet->saddr, inet->daddr);
+}
+
+EXPORT_SYMBOL_GPL(dccp_v4_send_check);
+
+static inline u64 dccp_v4_init_sequence(const struct sk_buff *skb)
+{
+	return secure_dccp_sequence_number(ip_hdr(skb)->daddr,
+					   ip_hdr(skb)->saddr,
+					   dccp_hdr(skb)->dccph_dport,
+					   dccp_hdr(skb)->dccph_sport);
+}
+
+/*
+ * The three way handshake has completed - we got a valid ACK or DATAACK -
+ * now create the new socket.
+ *
+ * This is the equivalent of TCP's tcp_v4_syn_recv_sock
+ */
+struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
+				       struct request_sock *req,
+				       struct dst_entry *dst)
+{
+	struct inet_request_sock *ireq;
+	struct inet_sock *newinet;
+	struct sock *newsk;
+
+	if (sk_acceptq_is_full(sk))
+		goto exit_overflow;
+
+	if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
+		goto exit;
+
+	newsk = dccp_create_openreq_child(sk, req, skb);
+	if (newsk == NULL)
+		goto exit;
+
+	sk_setup_caps(newsk, dst);
+
+	newinet		   = inet_sk(newsk);
+	ireq		   = inet_rsk(req);
+	newinet->daddr	   = ireq->rmt_addr;
+	newinet->rcv_saddr = ireq->loc_addr;
+	newinet->saddr	   = ireq->loc_addr;
+	newinet->opt	   = ireq->opt;
+	ireq->opt	   = NULL;
+	newinet->mc_index  = inet_iif(skb);
+	newinet->mc_ttl	   = ip_hdr(skb)->ttl;
+	newinet->id	   = jiffies;
+
+	dccp_sync_mss(newsk, dst_mtu(dst));
+
+	__inet_hash_nolisten(newsk);
+	__inet_inherit_port(sk, newsk);
+
+	return newsk;
+
+exit_overflow:
+	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
+exit:
+	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
+	dst_release(dst);
+	return NULL;
+}
+
+EXPORT_SYMBOL_GPL(dccp_v4_request_recv_sock);
+
+static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh = dccp_hdr(skb);
+	const struct iphdr *iph = ip_hdr(skb);
+	struct sock *nsk;
+	struct request_sock **prev;
+	/* Find possible connection requests. */
+	struct request_sock *req = inet_csk_search_req(sk, &prev,
+						       dh->dccph_sport,
+						       iph->saddr, iph->daddr);
+	if (req != NULL)
+		return dccp_check_req(sk, skb, req, prev);
+
+	nsk = inet_lookup_established(sock_net(sk), &dccp_hashinfo,
+				      iph->saddr, dh->dccph_sport,
+				      iph->daddr, dh->dccph_dport,
+				      inet_iif(skb));
+	if (nsk != NULL) {
+		if (nsk->sk_state != DCCP_TIME_WAIT) {
+			bh_lock_sock(nsk);
+			return nsk;
+		}
+		inet_twsk_put(inet_twsk(nsk));
+		return NULL;
+	}
+
+	return sk;
+}
+
+static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
+					   struct sk_buff *skb)
+{
+	struct rtable *rt;
+	struct flowi fl = { .oif = skb->rtable->rt_iif,
+			    .nl_u = { .ip4_u =
+				      { .daddr = ip_hdr(skb)->saddr,
+					.saddr = ip_hdr(skb)->daddr,
+					.tos = RT_CONN_FLAGS(sk) } },
+			    .proto = sk->sk_protocol,
+			    .uli_u = { .ports =
+				       { .sport = dccp_hdr(skb)->dccph_dport,
+					 .dport = dccp_hdr(skb)->dccph_sport }
+				     }
+			  };
+
+	security_skb_classify_flow(skb, &fl);
+	if (ip_route_output_flow(net, &rt, &fl, sk, 0)) {
+		IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
+		return NULL;
+	}
+
+	return &rt->u.dst;
+}
+
+static int dccp_v4_send_response(struct sock *sk, struct request_sock *req)
+{
+	int err = -1;
+	struct sk_buff *skb;
+	struct dst_entry *dst;
+
+	dst = inet_csk_route_req(sk, req);
+	if (dst == NULL)
+		goto out;
+
+	skb = dccp_make_response(sk, dst, req);
+	if (skb != NULL) {
+		const struct inet_request_sock *ireq = inet_rsk(req);
+		struct dccp_hdr *dh = dccp_hdr(skb);
+
+		dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->loc_addr,
+							      ireq->rmt_addr);
+		err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
+					    ireq->rmt_addr,
+					    ireq->opt);
+		err = net_xmit_eval(err);
+	}
+
+out:
+	dst_release(dst);
+	return err;
+}
+
+static void dccp_v4_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
+{
+	int err;
+	const struct iphdr *rxiph;
+	struct sk_buff *skb;
+	struct dst_entry *dst;
+	struct net *net = dev_net(rxskb->dst->dev);
+	struct sock *ctl_sk = net->dccp.v4_ctl_sk;
+
+	/* Never send a reset in response to a reset. */
+	if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
+		return;
+
+	if (rxskb->rtable->rt_type != RTN_LOCAL)
+		return;
+
+	dst = dccp_v4_route_skb(net, ctl_sk, rxskb);
+	if (dst == NULL)
+		return;
+
+	skb = dccp_ctl_make_reset(ctl_sk, rxskb);
+	if (skb == NULL)
+		goto out;
+
+	rxiph = ip_hdr(rxskb);
+	dccp_hdr(skb)->dccph_checksum = dccp_v4_csum_finish(skb, rxiph->saddr,
+								 rxiph->daddr);
+	skb->dst = dst_clone(dst);
+
+	bh_lock_sock(ctl_sk);
+	err = ip_build_and_send_pkt(skb, ctl_sk,
+				    rxiph->daddr, rxiph->saddr, NULL);
+	bh_unlock_sock(ctl_sk);
+
+	if (net_xmit_eval(err) == 0) {
+		DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
+		DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
+	}
+out:
+	 dst_release(dst);
+}
+
+static void dccp_v4_reqsk_destructor(struct request_sock *req)
+{
+	kfree(inet_rsk(req)->opt);
+}
+
+static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
+	.family		= PF_INET,
+	.obj_size	= sizeof(struct dccp_request_sock),
+	.rtx_syn_ack	= dccp_v4_send_response,
+	.send_ack	= dccp_reqsk_send_ack,
+	.destructor	= dccp_v4_reqsk_destructor,
+	.send_reset	= dccp_v4_ctl_send_reset,
+};
+
+int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
+{
+	struct inet_request_sock *ireq;
+	struct request_sock *req;
+	struct dccp_request_sock *dreq;
+	const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
+	struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
+
+	/* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
+	if (skb->rtable->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
+		return 0;	/* discard, don't send a reset here */
+
+	if (dccp_bad_service_code(sk, service)) {
+		dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
+		goto drop;
+	}
+	/*
+	 * TW buckets are converted to open requests without
+	 * limitations, they conserve resources and peer is
+	 * evidently real one.
+	 */
+	dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
+	if (inet_csk_reqsk_queue_is_full(sk))
+		goto drop;
+
+	/*
+	 * Accept backlog is full. If we have already queued enough
+	 * of warm entries in syn queue, drop request. It is better than
+	 * clogging syn queue with openreqs with exponentially increasing
+	 * timeout.
+	 */
+	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
+		goto drop;
+
+	req = inet_reqsk_alloc(&dccp_request_sock_ops);
+	if (req == NULL)
+		goto drop;
+
+	dccp_reqsk_init(req, skb);
+
+	dreq = dccp_rsk(req);
+	if (dccp_parse_options(sk, dreq, skb))
+		goto drop_and_free;
+
+	if (security_inet_conn_request(sk, skb, req))
+		goto drop_and_free;
+
+	ireq = inet_rsk(req);
+	ireq->loc_addr = ip_hdr(skb)->daddr;
+	ireq->rmt_addr = ip_hdr(skb)->saddr;
+
+	/*
+	 * Step 3: Process LISTEN state
+	 *
+	 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
+	 *
+	 * In fact we defer setting S.GSR, S.SWL, S.SWH to
+	 * dccp_create_openreq_child.
+	 */
+	dreq->dreq_isr	   = dcb->dccpd_seq;
+	dreq->dreq_iss	   = dccp_v4_init_sequence(skb);
+	dreq->dreq_service = service;
+
+	if (dccp_v4_send_response(sk, req))
+		goto drop_and_free;
+
+	inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
+	return 0;
+
+drop_and_free:
+	reqsk_free(req);
+drop:
+	DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
+	return -1;
+}
+
+EXPORT_SYMBOL_GPL(dccp_v4_conn_request);
+
+int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
+{
+	struct dccp_hdr *dh = dccp_hdr(skb);
+
+	if (sk->sk_state == DCCP_OPEN) { /* Fast path */
+		if (dccp_rcv_established(sk, skb, dh, skb->len))
+			goto reset;
+		return 0;
+	}
+
+	/*
+	 *  Step 3: Process LISTEN state
+	 *	 If P.type == Request or P contains a valid Init Cookie option,
+	 *	      (* Must scan the packet's options to check for Init
+	 *		 Cookies.  Only Init Cookies are processed here,
+	 *		 however; other options are processed in Step 8.  This
+	 *		 scan need only be performed if the endpoint uses Init
+	 *		 Cookies *)
+	 *	      (* Generate a new socket and switch to that socket *)
+	 *	      Set S := new socket for this port pair
+	 *	      S.state = RESPOND
+	 *	      Choose S.ISS (initial seqno) or set from Init Cookies
+	 *	      Initialize S.GAR := S.ISS
+	 *	      Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
+	 *	      Continue with S.state == RESPOND
+	 *	      (* A Response packet will be generated in Step 11 *)
+	 *	 Otherwise,
+	 *	      Generate Reset(No Connection) unless P.type == Reset
+	 *	      Drop packet and return
+	 *
+	 * NOTE: the check for the packet types is done in
+	 *	 dccp_rcv_state_process
+	 */
+	if (sk->sk_state == DCCP_LISTEN) {
+		struct sock *nsk = dccp_v4_hnd_req(sk, skb);
+
+		if (nsk == NULL)
+			goto discard;
+
+		if (nsk != sk) {
+			if (dccp_child_process(sk, nsk, skb))
+				goto reset;
+			return 0;
+		}
+	}
+
+	if (dccp_rcv_state_process(sk, skb, dh, skb->len))
+		goto reset;
+	return 0;
+
+reset:
+	dccp_v4_ctl_send_reset(sk, skb);
+discard:
+	kfree_skb(skb);
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_v4_do_rcv);
+
+/**
+ *	dccp_invalid_packet  -  check for malformed packets
+ *	Implements RFC 4340, 8.5:  Step 1: Check header basics
+ *	Packets that fail these checks are ignored and do not receive Resets.
+ */
+int dccp_invalid_packet(struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh;
+	unsigned int cscov;
+
+	if (skb->pkt_type != PACKET_HOST)
+		return 1;
+
+	/* If the packet is shorter than 12 bytes, drop packet and return */
+	if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
+		DCCP_WARN("pskb_may_pull failed\n");
+		return 1;
+	}
+
+	dh = dccp_hdr(skb);
+
+	/* If P.type is not understood, drop packet and return */
+	if (dh->dccph_type >= DCCP_PKT_INVALID) {
+		DCCP_WARN("invalid packet type\n");
+		return 1;
+	}
+
+	/*
+	 * If P.Data Offset is too small for packet type, drop packet and return
+	 */
+	if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
+		DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
+		return 1;
+	}
+	/*
+	 * If P.Data Offset is too too large for packet, drop packet and return
+	 */
+	if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
+		DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
+		return 1;
+	}
+
+	/*
+	 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
+	 * has short sequence numbers), drop packet and return
+	 */
+	if ((dh->dccph_type < DCCP_PKT_DATA    ||
+	    dh->dccph_type > DCCP_PKT_DATAACK) && dh->dccph_x == 0)  {
+		DCCP_WARN("P.type (%s) not Data || [Data]Ack, while P.X == 0\n",
+			  dccp_packet_name(dh->dccph_type));
+		return 1;
+	}
+
+	/*
+	 * If P.CsCov is too large for the packet size, drop packet and return.
+	 * This must come _before_ checksumming (not as RFC 4340 suggests).
+	 */
+	cscov = dccp_csum_coverage(skb);
+	if (cscov > skb->len) {
+		DCCP_WARN("P.CsCov %u exceeds packet length %d\n",
+			  dh->dccph_cscov, skb->len);
+		return 1;
+	}
+
+	/* If header checksum is incorrect, drop packet and return.
+	 * (This step is completed in the AF-dependent functions.) */
+	skb->csum = skb_checksum(skb, 0, cscov, 0);
+
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_invalid_packet);
+
+/* this is called when real data arrives */
+static int dccp_v4_rcv(struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh;
+	const struct iphdr *iph;
+	struct sock *sk;
+	int min_cov;
+
+	/* Step 1: Check header basics */
+
+	if (dccp_invalid_packet(skb))
+		goto discard_it;
+
+	iph = ip_hdr(skb);
+	/* Step 1: If header checksum is incorrect, drop packet and return */
+	if (dccp_v4_csum_finish(skb, iph->saddr, iph->daddr)) {
+		DCCP_WARN("dropped packet with invalid checksum\n");
+		goto discard_it;
+	}
+
+	dh = dccp_hdr(skb);
+
+	DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(dh);
+	DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
+
+	dccp_pr_debug("%8.8s "
+		      "src=%u.%u.%u.%u@%-5d "
+		      "dst=%u.%u.%u.%u@%-5d seq=%llu",
+		      dccp_packet_name(dh->dccph_type),
+		      NIPQUAD(iph->saddr), ntohs(dh->dccph_sport),
+		      NIPQUAD(iph->daddr), ntohs(dh->dccph_dport),
+		      (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
+
+	if (dccp_packet_without_ack(skb)) {
+		DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
+		dccp_pr_debug_cat("\n");
+	} else {
+		DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
+		dccp_pr_debug_cat(", ack=%llu\n", (unsigned long long)
+				  DCCP_SKB_CB(skb)->dccpd_ack_seq);
+	}
+
+	/* Step 2:
+	 *	Look up flow ID in table and get corresponding socket */
+	sk = __inet_lookup_skb(&dccp_hashinfo, skb,
+			       dh->dccph_sport, dh->dccph_dport);
+	/*
+	 * Step 2:
+	 *	If no socket ...
+	 */
+	if (sk == NULL) {
+		dccp_pr_debug("failed to look up flow ID in table and "
+			      "get corresponding socket\n");
+		goto no_dccp_socket;
+	}
+
+	/*
+	 * Step 2:
+	 *	... or S.state == TIMEWAIT,
+	 *		Generate Reset(No Connection) unless P.type == Reset
+	 *		Drop packet and return
+	 */
+	if (sk->sk_state == DCCP_TIME_WAIT) {
+		dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
+		inet_twsk_put(inet_twsk(sk));
+		goto no_dccp_socket;
+	}
+
+	/*
+	 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
+	 *	o if MinCsCov = 0, only packets with CsCov = 0 are accepted
+	 *	o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
+	 */
+	min_cov = dccp_sk(sk)->dccps_pcrlen;
+	if (dh->dccph_cscov && (min_cov == 0 || dh->dccph_cscov < min_cov))  {
+		dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
+			      dh->dccph_cscov, min_cov);
+		/* FIXME: "Such packets SHOULD be reported using Data Dropped
+		 *         options (Section 11.7) with Drop Code 0, Protocol
+		 *         Constraints."                                     */
+		goto discard_and_relse;
+	}
+
+	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
+		goto discard_and_relse;
+	nf_reset(skb);
+
+	return sk_receive_skb(sk, skb, 1);
+
+no_dccp_socket:
+	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
+		goto discard_it;
+	/*
+	 * Step 2:
+	 *	If no socket ...
+	 *		Generate Reset(No Connection) unless P.type == Reset
+	 *		Drop packet and return
+	 */
+	if (dh->dccph_type != DCCP_PKT_RESET) {
+		DCCP_SKB_CB(skb)->dccpd_reset_code =
+					DCCP_RESET_CODE_NO_CONNECTION;
+		dccp_v4_ctl_send_reset(sk, skb);
+	}
+
+discard_it:
+	kfree_skb(skb);
+	return 0;
+
+discard_and_relse:
+	sock_put(sk);
+	goto discard_it;
+}
+
+static struct inet_connection_sock_af_ops dccp_ipv4_af_ops = {
+	.queue_xmit	   = ip_queue_xmit,
+	.send_check	   = dccp_v4_send_check,
+	.rebuild_header	   = inet_sk_rebuild_header,
+	.conn_request	   = dccp_v4_conn_request,
+	.syn_recv_sock	   = dccp_v4_request_recv_sock,
+	.net_header_len	   = sizeof(struct iphdr),
+	.setsockopt	   = ip_setsockopt,
+	.getsockopt	   = ip_getsockopt,
+	.addr2sockaddr	   = inet_csk_addr2sockaddr,
+	.sockaddr_len	   = sizeof(struct sockaddr_in),
+	.bind_conflict	   = inet_csk_bind_conflict,
+#ifdef CONFIG_COMPAT
+	.compat_setsockopt = compat_ip_setsockopt,
+	.compat_getsockopt = compat_ip_getsockopt,
+#endif
+};
+
+static int dccp_v4_init_sock(struct sock *sk)
+{
+	static __u8 dccp_v4_ctl_sock_initialized;
+	int err = dccp_init_sock(sk, dccp_v4_ctl_sock_initialized);
+
+	if (err == 0) {
+		if (unlikely(!dccp_v4_ctl_sock_initialized))
+			dccp_v4_ctl_sock_initialized = 1;
+		inet_csk(sk)->icsk_af_ops = &dccp_ipv4_af_ops;
+	}
+
+	return err;
+}
+
+static struct timewait_sock_ops dccp_timewait_sock_ops = {
+	.twsk_obj_size	= sizeof(struct inet_timewait_sock),
+};
+
+static struct proto dccp_v4_prot = {
+	.name			= "DCCP",
+	.owner			= THIS_MODULE,
+	.close			= dccp_close,
+	.connect		= dccp_v4_connect,
+	.disconnect		= dccp_disconnect,
+	.ioctl			= dccp_ioctl,
+	.init			= dccp_v4_init_sock,
+	.setsockopt		= dccp_setsockopt,
+	.getsockopt		= dccp_getsockopt,
+	.sendmsg		= dccp_sendmsg,
+	.recvmsg		= dccp_recvmsg,
+	.backlog_rcv		= dccp_v4_do_rcv,
+	.hash			= inet_hash,
+	.unhash			= inet_unhash,
+	.accept			= inet_csk_accept,
+	.get_port		= inet_csk_get_port,
+	.shutdown		= dccp_shutdown,
+	.destroy		= dccp_destroy_sock,
+	.orphan_count		= &dccp_orphan_count,
+	.max_header		= MAX_DCCP_HEADER,
+	.obj_size		= sizeof(struct dccp_sock),
+	.rsk_prot		= &dccp_request_sock_ops,
+	.twsk_prot		= &dccp_timewait_sock_ops,
+	.h.hashinfo		= &dccp_hashinfo,
+#ifdef CONFIG_COMPAT
+	.compat_setsockopt	= compat_dccp_setsockopt,
+	.compat_getsockopt	= compat_dccp_getsockopt,
+#endif
+};
+
+static struct net_protocol dccp_v4_protocol = {
+	.handler	= dccp_v4_rcv,
+	.err_handler	= dccp_v4_err,
+	.no_policy	= 1,
+	.netns_ok	= 1,
+};
+
+static const struct proto_ops inet_dccp_ops = {
+	.family		   = PF_INET,
+	.owner		   = THIS_MODULE,
+	.release	   = inet_release,
+	.bind		   = inet_bind,
+	.connect	   = inet_stream_connect,
+	.socketpair	   = sock_no_socketpair,
+	.accept		   = inet_accept,
+	.getname	   = inet_getname,
+	/* FIXME: work on tcp_poll to rename it to inet_csk_poll */
+	.poll		   = dccp_poll,
+	.ioctl		   = inet_ioctl,
+	/* FIXME: work on inet_listen to rename it to sock_common_listen */
+	.listen		   = inet_dccp_listen,
+	.shutdown	   = inet_shutdown,
+	.setsockopt	   = sock_common_setsockopt,
+	.getsockopt	   = sock_common_getsockopt,
+	.sendmsg	   = inet_sendmsg,
+	.recvmsg	   = sock_common_recvmsg,
+	.mmap		   = sock_no_mmap,
+	.sendpage	   = sock_no_sendpage,
+#ifdef CONFIG_COMPAT
+	.compat_setsockopt = compat_sock_common_setsockopt,
+	.compat_getsockopt = compat_sock_common_getsockopt,
+#endif
+};
+
+static struct inet_protosw dccp_v4_protosw = {
+	.type		= SOCK_DCCP,
+	.protocol	= IPPROTO_DCCP,
+	.prot		= &dccp_v4_prot,
+	.ops		= &inet_dccp_ops,
+	.capability	= -1,
+	.no_check	= 0,
+	.flags		= INET_PROTOSW_ICSK,
+};
+
+static int dccp_v4_init_net(struct net *net)
+{
+	int err;
+
+	err = inet_ctl_sock_create(&net->dccp.v4_ctl_sk, PF_INET,
+				   SOCK_DCCP, IPPROTO_DCCP, net);
+	return err;
+}
+
+static void dccp_v4_exit_net(struct net *net)
+{
+	inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
+}
+
+static struct pernet_operations dccp_v4_ops = {
+	.init	= dccp_v4_init_net,
+	.exit	= dccp_v4_exit_net,
+};
+
+static int __init dccp_v4_init(void)
+{
+	int err = proto_register(&dccp_v4_prot, 1);
+
+	if (err != 0)
+		goto out;
+
+	err = inet_add_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
+	if (err != 0)
+		goto out_proto_unregister;
+
+	inet_register_protosw(&dccp_v4_protosw);
+
+	err = register_pernet_subsys(&dccp_v4_ops);
+	if (err)
+		goto out_destroy_ctl_sock;
+out:
+	return err;
+out_destroy_ctl_sock:
+	inet_unregister_protosw(&dccp_v4_protosw);
+	inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
+out_proto_unregister:
+	proto_unregister(&dccp_v4_prot);
+	goto out;
+}
+
+static void __exit dccp_v4_exit(void)
+{
+	unregister_pernet_subsys(&dccp_v4_ops);
+	inet_unregister_protosw(&dccp_v4_protosw);
+	inet_del_protocol(&dccp_v4_protocol, IPPROTO_DCCP);
+	proto_unregister(&dccp_v4_prot);
+}
+
+module_init(dccp_v4_init);
+module_exit(dccp_v4_exit);
+
+/*
+ * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
+ * values directly, Also cover the case where the protocol is not specified,
+ * i.e. net-pf-PF_INET-proto-0-type-SOCK_DCCP
+ */
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 33, 6);
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 0, 6);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
+MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
new file mode 100644
index 0000000..d4ce122
--- /dev/null
+++ b/net/dccp/ipv6.c
@@ -0,0 +1,1256 @@
+/*
+ *	DCCP over IPv6
+ *	Linux INET6 implementation
+ *
+ *	Based on net/dccp6/ipv6.c
+ *
+ *	Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/xfrm.h>
+
+#include <net/addrconf.h>
+#include <net/inet_common.h>
+#include <net/inet_hashtables.h>
+#include <net/inet_sock.h>
+#include <net/inet6_connection_sock.h>
+#include <net/inet6_hashtables.h>
+#include <net/ip6_route.h>
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <net/transp_v6.h>
+#include <net/ip6_checksum.h>
+#include <net/xfrm.h>
+
+#include "dccp.h"
+#include "ipv6.h"
+#include "feat.h"
+
+/* The per-net dccp.v6_ctl_sk is used for sending RSTs and ACKs */
+
+static struct inet_connection_sock_af_ops dccp_ipv6_mapped;
+static struct inet_connection_sock_af_ops dccp_ipv6_af_ops;
+
+static void dccp_v6_hash(struct sock *sk)
+{
+	if (sk->sk_state != DCCP_CLOSED) {
+		if (inet_csk(sk)->icsk_af_ops == &dccp_ipv6_mapped) {
+			inet_hash(sk);
+			return;
+		}
+		local_bh_disable();
+		__inet6_hash(sk);
+		local_bh_enable();
+	}
+}
+
+/* add pseudo-header to DCCP checksum stored in skb->csum */
+static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb,
+				      struct in6_addr *saddr,
+				      struct in6_addr *daddr)
+{
+	return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum);
+}
+
+static inline void dccp_v6_send_check(struct sock *sk, int unused_value,
+				      struct sk_buff *skb)
+{
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct dccp_hdr *dh = dccp_hdr(skb);
+
+	dccp_csum_outgoing(skb);
+	dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &np->daddr);
+}
+
+static inline __u32 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
+						  __be16 sport, __be16 dport   )
+{
+	return secure_tcpv6_sequence_number(saddr, daddr, sport, dport);
+}
+
+static inline __u32 dccp_v6_init_sequence(struct sk_buff *skb)
+{
+	return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
+					     ipv6_hdr(skb)->saddr.s6_addr32,
+					     dccp_hdr(skb)->dccph_dport,
+					     dccp_hdr(skb)->dccph_sport     );
+
+}
+
+static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+			int type, int code, int offset, __be32 info)
+{
+	struct ipv6hdr *hdr = (struct ipv6hdr *)skb->data;
+	const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
+	struct dccp_sock *dp;
+	struct ipv6_pinfo *np;
+	struct sock *sk;
+	int err;
+	__u64 seq;
+	struct net *net = dev_net(skb->dev);
+
+	if (skb->len < offset + sizeof(*dh) ||
+	    skb->len < offset + __dccp_basic_hdr_len(dh)) {
+		ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
+				   ICMP6_MIB_INERRORS);
+		return;
+	}
+
+	sk = inet6_lookup(net, &dccp_hashinfo,
+			&hdr->daddr, dh->dccph_dport,
+			&hdr->saddr, dh->dccph_sport, inet6_iif(skb));
+
+	if (sk == NULL) {
+		ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
+				   ICMP6_MIB_INERRORS);
+		return;
+	}
+
+	if (sk->sk_state == DCCP_TIME_WAIT) {
+		inet_twsk_put(inet_twsk(sk));
+		return;
+	}
+
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk))
+		NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
+
+	if (sk->sk_state == DCCP_CLOSED)
+		goto out;
+
+	dp = dccp_sk(sk);
+	seq = dccp_hdr_seq(dh);
+	if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
+	    !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
+		NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
+		goto out;
+	}
+
+	np = inet6_sk(sk);
+
+	if (type == ICMPV6_PKT_TOOBIG) {
+		struct dst_entry *dst = NULL;
+
+		if (sock_owned_by_user(sk))
+			goto out;
+		if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
+			goto out;
+
+		/* icmp should have updated the destination cache entry */
+		dst = __sk_dst_check(sk, np->dst_cookie);
+		if (dst == NULL) {
+			struct inet_sock *inet = inet_sk(sk);
+			struct flowi fl;
+
+			/* BUGGG_FUTURE: Again, it is not clear how
+			   to handle rthdr case. Ignore this complexity
+			   for now.
+			 */
+			memset(&fl, 0, sizeof(fl));
+			fl.proto = IPPROTO_DCCP;
+			ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
+			ipv6_addr_copy(&fl.fl6_src, &np->saddr);
+			fl.oif = sk->sk_bound_dev_if;
+			fl.fl_ip_dport = inet->dport;
+			fl.fl_ip_sport = inet->sport;
+			security_sk_classify_flow(sk, &fl);
+
+			err = ip6_dst_lookup(sk, &dst, &fl);
+			if (err) {
+				sk->sk_err_soft = -err;
+				goto out;
+			}
+
+			err = xfrm_lookup(&dst, &fl, sk, 0);
+			if (err < 0) {
+				sk->sk_err_soft = -err;
+				goto out;
+			}
+		} else
+			dst_hold(dst);
+
+		if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
+			dccp_sync_mss(sk, dst_mtu(dst));
+		} /* else let the usual retransmit timer handle it */
+		dst_release(dst);
+		goto out;
+	}
+
+	icmpv6_err_convert(type, code, &err);
+
+	/* Might be for an request_sock */
+	switch (sk->sk_state) {
+		struct request_sock *req, **prev;
+	case DCCP_LISTEN:
+		if (sock_owned_by_user(sk))
+			goto out;
+
+		req = inet6_csk_search_req(sk, &prev, dh->dccph_dport,
+					   &hdr->daddr, &hdr->saddr,
+					   inet6_iif(skb));
+		if (req == NULL)
+			goto out;
+
+		/*
+		 * ICMPs are not backlogged, hence we cannot get an established
+		 * socket here.
+		 */
+		WARN_ON(req->sk != NULL);
+
+		if (seq != dccp_rsk(req)->dreq_iss) {
+			NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
+			goto out;
+		}
+
+		inet_csk_reqsk_queue_drop(sk, req, prev);
+		goto out;
+
+	case DCCP_REQUESTING:
+	case DCCP_RESPOND:  /* Cannot happen.
+			       It can, it SYNs are crossed. --ANK */
+		if (!sock_owned_by_user(sk)) {
+			DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
+			sk->sk_err = err;
+			/*
+			 * Wake people up to see the error
+			 * (see connect in sock.c)
+			 */
+			sk->sk_error_report(sk);
+			dccp_done(sk);
+		} else
+			sk->sk_err_soft = err;
+		goto out;
+	}
+
+	if (!sock_owned_by_user(sk) && np->recverr) {
+		sk->sk_err = err;
+		sk->sk_error_report(sk);
+	} else
+		sk->sk_err_soft = err;
+
+out:
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
+
+
+static int dccp_v6_send_response(struct sock *sk, struct request_sock *req)
+{
+	struct inet6_request_sock *ireq6 = inet6_rsk(req);
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct sk_buff *skb;
+	struct ipv6_txoptions *opt = NULL;
+	struct in6_addr *final_p = NULL, final;
+	struct flowi fl;
+	int err = -1;
+	struct dst_entry *dst;
+
+	memset(&fl, 0, sizeof(fl));
+	fl.proto = IPPROTO_DCCP;
+	ipv6_addr_copy(&fl.fl6_dst, &ireq6->rmt_addr);
+	ipv6_addr_copy(&fl.fl6_src, &ireq6->loc_addr);
+	fl.fl6_flowlabel = 0;
+	fl.oif = ireq6->iif;
+	fl.fl_ip_dport = inet_rsk(req)->rmt_port;
+	fl.fl_ip_sport = inet_rsk(req)->loc_port;
+	security_req_classify_flow(req, &fl);
+
+	opt = np->opt;
+
+	if (opt != NULL && opt->srcrt != NULL) {
+		const struct rt0_hdr *rt0 = (struct rt0_hdr *)opt->srcrt;
+
+		ipv6_addr_copy(&final, &fl.fl6_dst);
+		ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
+		final_p = &final;
+	}
+
+	err = ip6_dst_lookup(sk, &dst, &fl);
+	if (err)
+		goto done;
+
+	if (final_p)
+		ipv6_addr_copy(&fl.fl6_dst, final_p);
+
+	err = xfrm_lookup(&dst, &fl, sk, 0);
+	if (err < 0)
+		goto done;
+
+	skb = dccp_make_response(sk, dst, req);
+	if (skb != NULL) {
+		struct dccp_hdr *dh = dccp_hdr(skb);
+
+		dh->dccph_checksum = dccp_v6_csum_finish(skb,
+							 &ireq6->loc_addr,
+							 &ireq6->rmt_addr);
+		ipv6_addr_copy(&fl.fl6_dst, &ireq6->rmt_addr);
+		err = ip6_xmit(sk, skb, &fl, opt, 0);
+		err = net_xmit_eval(err);
+	}
+
+done:
+	if (opt != NULL && opt != np->opt)
+		sock_kfree_s(sk, opt, opt->tot_len);
+	dst_release(dst);
+	return err;
+}
+
+static void dccp_v6_reqsk_destructor(struct request_sock *req)
+{
+	if (inet6_rsk(req)->pktopts != NULL)
+		kfree_skb(inet6_rsk(req)->pktopts);
+}
+
+static void dccp_v6_ctl_send_reset(struct sock *sk, struct sk_buff *rxskb)
+{
+	struct ipv6hdr *rxip6h;
+	struct sk_buff *skb;
+	struct flowi fl;
+	struct net *net = dev_net(rxskb->dst->dev);
+	struct sock *ctl_sk = net->dccp.v6_ctl_sk;
+
+	if (dccp_hdr(rxskb)->dccph_type == DCCP_PKT_RESET)
+		return;
+
+	if (!ipv6_unicast_destination(rxskb))
+		return;
+
+	skb = dccp_ctl_make_reset(ctl_sk, rxskb);
+	if (skb == NULL)
+		return;
+
+	rxip6h = ipv6_hdr(rxskb);
+	dccp_hdr(skb)->dccph_checksum = dccp_v6_csum_finish(skb, &rxip6h->saddr,
+							    &rxip6h->daddr);
+
+	memset(&fl, 0, sizeof(fl));
+	ipv6_addr_copy(&fl.fl6_dst, &rxip6h->saddr);
+	ipv6_addr_copy(&fl.fl6_src, &rxip6h->daddr);
+
+	fl.proto = IPPROTO_DCCP;
+	fl.oif = inet6_iif(rxskb);
+	fl.fl_ip_dport = dccp_hdr(skb)->dccph_dport;
+	fl.fl_ip_sport = dccp_hdr(skb)->dccph_sport;
+	security_skb_classify_flow(rxskb, &fl);
+
+	/* sk = NULL, but it is safe for now. RST socket required. */
+	if (!ip6_dst_lookup(ctl_sk, &skb->dst, &fl)) {
+		if (xfrm_lookup(&skb->dst, &fl, NULL, 0) >= 0) {
+			ip6_xmit(ctl_sk, skb, &fl, NULL, 0);
+			DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
+			DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
+			return;
+		}
+	}
+
+	kfree_skb(skb);
+}
+
+static struct request_sock_ops dccp6_request_sock_ops = {
+	.family		= AF_INET6,
+	.obj_size	= sizeof(struct dccp6_request_sock),
+	.rtx_syn_ack	= dccp_v6_send_response,
+	.send_ack	= dccp_reqsk_send_ack,
+	.destructor	= dccp_v6_reqsk_destructor,
+	.send_reset	= dccp_v6_ctl_send_reset,
+};
+
+static struct sock *dccp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh = dccp_hdr(skb);
+	const struct ipv6hdr *iph = ipv6_hdr(skb);
+	struct sock *nsk;
+	struct request_sock **prev;
+	/* Find possible connection requests. */
+	struct request_sock *req = inet6_csk_search_req(sk, &prev,
+							dh->dccph_sport,
+							&iph->saddr,
+							&iph->daddr,
+							inet6_iif(skb));
+	if (req != NULL)
+		return dccp_check_req(sk, skb, req, prev);
+
+	nsk = __inet6_lookup_established(sock_net(sk), &dccp_hashinfo,
+					 &iph->saddr, dh->dccph_sport,
+					 &iph->daddr, ntohs(dh->dccph_dport),
+					 inet6_iif(skb));
+	if (nsk != NULL) {
+		if (nsk->sk_state != DCCP_TIME_WAIT) {
+			bh_lock_sock(nsk);
+			return nsk;
+		}
+		inet_twsk_put(inet_twsk(nsk));
+		return NULL;
+	}
+
+	return sk;
+}
+
+static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
+{
+	struct request_sock *req;
+	struct dccp_request_sock *dreq;
+	struct inet6_request_sock *ireq6;
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	const __be32 service = dccp_hdr_request(skb)->dccph_req_service;
+	struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
+
+	if (skb->protocol == htons(ETH_P_IP))
+		return dccp_v4_conn_request(sk, skb);
+
+	if (!ipv6_unicast_destination(skb))
+		return 0;	/* discard, don't send a reset here */
+
+	if (dccp_bad_service_code(sk, service)) {
+		dcb->dccpd_reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
+		goto drop;
+	}
+	/*
+	 * There are no SYN attacks on IPv6, yet...
+	 */
+	dcb->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
+	if (inet_csk_reqsk_queue_is_full(sk))
+		goto drop;
+
+	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
+		goto drop;
+
+	req = inet6_reqsk_alloc(&dccp6_request_sock_ops);
+	if (req == NULL)
+		goto drop;
+
+	dccp_reqsk_init(req, skb);
+
+	dreq = dccp_rsk(req);
+	if (dccp_parse_options(sk, dreq, skb))
+		goto drop_and_free;
+
+	if (security_inet_conn_request(sk, skb, req))
+		goto drop_and_free;
+
+	ireq6 = inet6_rsk(req);
+	ipv6_addr_copy(&ireq6->rmt_addr, &ipv6_hdr(skb)->saddr);
+	ipv6_addr_copy(&ireq6->loc_addr, &ipv6_hdr(skb)->daddr);
+
+	if (ipv6_opt_accepted(sk, skb) ||
+	    np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
+	    np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
+		atomic_inc(&skb->users);
+		ireq6->pktopts = skb;
+	}
+	ireq6->iif = sk->sk_bound_dev_if;
+
+	/* So that link locals have meaning */
+	if (!sk->sk_bound_dev_if &&
+	    ipv6_addr_type(&ireq6->rmt_addr) & IPV6_ADDR_LINKLOCAL)
+		ireq6->iif = inet6_iif(skb);
+
+	/*
+	 * Step 3: Process LISTEN state
+	 *
+	 *   Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
+	 *
+	 *   In fact we defer setting S.GSR, S.SWL, S.SWH to
+	 *   dccp_create_openreq_child.
+	 */
+	dreq->dreq_isr	   = dcb->dccpd_seq;
+	dreq->dreq_iss	   = dccp_v6_init_sequence(skb);
+	dreq->dreq_service = service;
+
+	if (dccp_v6_send_response(sk, req))
+		goto drop_and_free;
+
+	inet6_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
+	return 0;
+
+drop_and_free:
+	reqsk_free(req);
+drop:
+	DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
+	return -1;
+}
+
+static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
+					      struct sk_buff *skb,
+					      struct request_sock *req,
+					      struct dst_entry *dst)
+{
+	struct inet6_request_sock *ireq6 = inet6_rsk(req);
+	struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
+	struct inet_sock *newinet;
+	struct dccp_sock *newdp;
+	struct dccp6_sock *newdp6;
+	struct sock *newsk;
+	struct ipv6_txoptions *opt;
+
+	if (skb->protocol == htons(ETH_P_IP)) {
+		/*
+		 *	v6 mapped
+		 */
+		newsk = dccp_v4_request_recv_sock(sk, skb, req, dst);
+		if (newsk == NULL)
+			return NULL;
+
+		newdp6 = (struct dccp6_sock *)newsk;
+		newdp = dccp_sk(newsk);
+		newinet = inet_sk(newsk);
+		newinet->pinet6 = &newdp6->inet6;
+		newnp = inet6_sk(newsk);
+
+		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
+
+		ipv6_addr_set(&newnp->daddr, 0, 0, htonl(0x0000FFFF),
+			      newinet->daddr);
+
+		ipv6_addr_set(&newnp->saddr, 0, 0, htonl(0x0000FFFF),
+			      newinet->saddr);
+
+		ipv6_addr_copy(&newnp->rcv_saddr, &newnp->saddr);
+
+		inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
+		newsk->sk_backlog_rcv = dccp_v4_do_rcv;
+		newnp->pktoptions  = NULL;
+		newnp->opt	   = NULL;
+		newnp->mcast_oif   = inet6_iif(skb);
+		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
+
+		/*
+		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
+		 * here, dccp_create_openreq_child now does this for us, see the comment in
+		 * that function for the gory details. -acme
+		 */
+
+		/* It is tricky place. Until this moment IPv4 tcp
+		   worked with IPv6 icsk.icsk_af_ops.
+		   Sync it now.
+		 */
+		dccp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
+
+		return newsk;
+	}
+
+	opt = np->opt;
+
+	if (sk_acceptq_is_full(sk))
+		goto out_overflow;
+
+	if (dst == NULL) {
+		struct in6_addr *final_p = NULL, final;
+		struct flowi fl;
+
+		memset(&fl, 0, sizeof(fl));
+		fl.proto = IPPROTO_DCCP;
+		ipv6_addr_copy(&fl.fl6_dst, &ireq6->rmt_addr);
+		if (opt != NULL && opt->srcrt != NULL) {
+			const struct rt0_hdr *rt0 = (struct rt0_hdr *)opt->srcrt;
+
+			ipv6_addr_copy(&final, &fl.fl6_dst);
+			ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
+			final_p = &final;
+		}
+		ipv6_addr_copy(&fl.fl6_src, &ireq6->loc_addr);
+		fl.oif = sk->sk_bound_dev_if;
+		fl.fl_ip_dport = inet_rsk(req)->rmt_port;
+		fl.fl_ip_sport = inet_rsk(req)->loc_port;
+		security_sk_classify_flow(sk, &fl);
+
+		if (ip6_dst_lookup(sk, &dst, &fl))
+			goto out;
+
+		if (final_p)
+			ipv6_addr_copy(&fl.fl6_dst, final_p);
+
+		if ((xfrm_lookup(&dst, &fl, sk, 0)) < 0)
+			goto out;
+	}
+
+	newsk = dccp_create_openreq_child(sk, req, skb);
+	if (newsk == NULL)
+		goto out;
+
+	/*
+	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
+	 * count here, dccp_create_openreq_child now does this for us, see the
+	 * comment in that function for the gory details. -acme
+	 */
+
+	__ip6_dst_store(newsk, dst, NULL, NULL);
+	newsk->sk_route_caps = dst->dev->features & ~(NETIF_F_IP_CSUM |
+						      NETIF_F_TSO);
+	newdp6 = (struct dccp6_sock *)newsk;
+	newinet = inet_sk(newsk);
+	newinet->pinet6 = &newdp6->inet6;
+	newdp = dccp_sk(newsk);
+	newnp = inet6_sk(newsk);
+
+	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
+
+	ipv6_addr_copy(&newnp->daddr, &ireq6->rmt_addr);
+	ipv6_addr_copy(&newnp->saddr, &ireq6->loc_addr);
+	ipv6_addr_copy(&newnp->rcv_saddr, &ireq6->loc_addr);
+	newsk->sk_bound_dev_if = ireq6->iif;
+
+	/* Now IPv6 options...
+
+	   First: no IPv4 options.
+	 */
+	newinet->opt = NULL;
+
+	/* Clone RX bits */
+	newnp->rxopt.all = np->rxopt.all;
+
+	/* Clone pktoptions received with SYN */
+	newnp->pktoptions = NULL;
+	if (ireq6->pktopts != NULL) {
+		newnp->pktoptions = skb_clone(ireq6->pktopts, GFP_ATOMIC);
+		kfree_skb(ireq6->pktopts);
+		ireq6->pktopts = NULL;
+		if (newnp->pktoptions)
+			skb_set_owner_r(newnp->pktoptions, newsk);
+	}
+	newnp->opt	  = NULL;
+	newnp->mcast_oif  = inet6_iif(skb);
+	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
+
+	/*
+	 * Clone native IPv6 options from listening socket (if any)
+	 *
+	 * Yes, keeping reference count would be much more clever, but we make
+	 * one more one thing there: reattach optmem to newsk.
+	 */
+	if (opt != NULL) {
+		newnp->opt = ipv6_dup_options(newsk, opt);
+		if (opt != np->opt)
+			sock_kfree_s(sk, opt, opt->tot_len);
+	}
+
+	inet_csk(newsk)->icsk_ext_hdr_len = 0;
+	if (newnp->opt != NULL)
+		inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
+						     newnp->opt->opt_flen);
+
+	dccp_sync_mss(newsk, dst_mtu(dst));
+
+	newinet->daddr = newinet->saddr = newinet->rcv_saddr = LOOPBACK4_IPV6;
+
+	__inet6_hash(newsk);
+	__inet_inherit_port(sk, newsk);
+
+	return newsk;
+
+out_overflow:
+	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
+out:
+	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
+	if (opt != NULL && opt != np->opt)
+		sock_kfree_s(sk, opt, opt->tot_len);
+	dst_release(dst);
+	return NULL;
+}
+
+/* The socket must have it's spinlock held when we get
+ * here.
+ *
+ * We have a potential double-lock case here, so even when
+ * doing backlog processing we use the BH locking scheme.
+ * This is because we cannot sleep with the original spinlock
+ * held.
+ */
+static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
+{
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct sk_buff *opt_skb = NULL;
+
+	/* Imagine: socket is IPv6. IPv4 packet arrives,
+	   goes to IPv4 receive handler and backlogged.
+	   From backlog it always goes here. Kerboom...
+	   Fortunately, dccp_rcv_established and rcv_established
+	   handle them correctly, but it is not case with
+	   dccp_v6_hnd_req and dccp_v6_ctl_send_reset().   --ANK
+	 */
+
+	if (skb->protocol == htons(ETH_P_IP))
+		return dccp_v4_do_rcv(sk, skb);
+
+	if (sk_filter(sk, skb))
+		goto discard;
+
+	/*
+	 * socket locking is here for SMP purposes as backlog rcv is currently
+	 * called with bh processing disabled.
+	 */
+
+	/* Do Stevens' IPV6_PKTOPTIONS.
+
+	   Yes, guys, it is the only place in our code, where we
+	   may make it not affecting IPv4.
+	   The rest of code is protocol independent,
+	   and I do not like idea to uglify IPv4.
+
+	   Actually, all the idea behind IPV6_PKTOPTIONS
+	   looks not very well thought. For now we latch
+	   options, received in the last packet, enqueued
+	   by tcp. Feel free to propose better solution.
+					       --ANK (980728)
+	 */
+	if (np->rxopt.all)
+	/*
+	 * FIXME: Add handling of IPV6_PKTOPTIONS skb. See the comments below
+	 *        (wrt ipv6_pktopions) and net/ipv6/tcp_ipv6.c for an example.
+	 */
+		opt_skb = skb_clone(skb, GFP_ATOMIC);
+
+	if (sk->sk_state == DCCP_OPEN) { /* Fast path */
+		if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
+			goto reset;
+		if (opt_skb) {
+			/* XXX This is where we would goto ipv6_pktoptions. */
+			__kfree_skb(opt_skb);
+		}
+		return 0;
+	}
+
+	/*
+	 *  Step 3: Process LISTEN state
+	 *     If S.state == LISTEN,
+	 *	 If P.type == Request or P contains a valid Init Cookie option,
+	 *	      (* Must scan the packet's options to check for Init
+	 *		 Cookies.  Only Init Cookies are processed here,
+	 *		 however; other options are processed in Step 8.  This
+	 *		 scan need only be performed if the endpoint uses Init
+	 *		 Cookies *)
+	 *	      (* Generate a new socket and switch to that socket *)
+	 *	      Set S := new socket for this port pair
+	 *	      S.state = RESPOND
+	 *	      Choose S.ISS (initial seqno) or set from Init Cookies
+	 *	      Initialize S.GAR := S.ISS
+	 *	      Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
+	 *	      Continue with S.state == RESPOND
+	 *	      (* A Response packet will be generated in Step 11 *)
+	 *	 Otherwise,
+	 *	      Generate Reset(No Connection) unless P.type == Reset
+	 *	      Drop packet and return
+	 *
+	 * NOTE: the check for the packet types is done in
+	 *	 dccp_rcv_state_process
+	 */
+	if (sk->sk_state == DCCP_LISTEN) {
+		struct sock *nsk = dccp_v6_hnd_req(sk, skb);
+
+		if (nsk == NULL)
+			goto discard;
+		/*
+		 * Queue it on the new socket if the new socket is active,
+		 * otherwise we just shortcircuit this and continue with
+		 * the new socket..
+		 */
+		if (nsk != sk) {
+			if (dccp_child_process(sk, nsk, skb))
+				goto reset;
+			if (opt_skb != NULL)
+				__kfree_skb(opt_skb);
+			return 0;
+		}
+	}
+
+	if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
+		goto reset;
+	if (opt_skb) {
+		/* XXX This is where we would goto ipv6_pktoptions. */
+		__kfree_skb(opt_skb);
+	}
+	return 0;
+
+reset:
+	dccp_v6_ctl_send_reset(sk, skb);
+discard:
+	if (opt_skb != NULL)
+		__kfree_skb(opt_skb);
+	kfree_skb(skb);
+	return 0;
+}
+
+static int dccp_v6_rcv(struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh;
+	struct sock *sk;
+	int min_cov;
+
+	/* Step 1: Check header basics */
+
+	if (dccp_invalid_packet(skb))
+		goto discard_it;
+
+	/* Step 1: If header checksum is incorrect, drop packet and return. */
+	if (dccp_v6_csum_finish(skb, &ipv6_hdr(skb)->saddr,
+				     &ipv6_hdr(skb)->daddr)) {
+		DCCP_WARN("dropped packet with invalid checksum\n");
+		goto discard_it;
+	}
+
+	dh = dccp_hdr(skb);
+
+	DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(dh);
+	DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
+
+	if (dccp_packet_without_ack(skb))
+		DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
+	else
+		DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
+
+	/* Step 2:
+	 *	Look up flow ID in table and get corresponding socket */
+	sk = __inet6_lookup_skb(&dccp_hashinfo, skb,
+			        dh->dccph_sport, dh->dccph_dport);
+	/*
+	 * Step 2:
+	 *	If no socket ...
+	 */
+	if (sk == NULL) {
+		dccp_pr_debug("failed to look up flow ID in table and "
+			      "get corresponding socket\n");
+		goto no_dccp_socket;
+	}
+
+	/*
+	 * Step 2:
+	 *	... or S.state == TIMEWAIT,
+	 *		Generate Reset(No Connection) unless P.type == Reset
+	 *		Drop packet and return
+	 */
+	if (sk->sk_state == DCCP_TIME_WAIT) {
+		dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
+		inet_twsk_put(inet_twsk(sk));
+		goto no_dccp_socket;
+	}
+
+	/*
+	 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
+	 *	o if MinCsCov = 0, only packets with CsCov = 0 are accepted
+	 *	o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
+	 */
+	min_cov = dccp_sk(sk)->dccps_pcrlen;
+	if (dh->dccph_cscov  &&  (min_cov == 0 || dh->dccph_cscov < min_cov))  {
+		dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
+			      dh->dccph_cscov, min_cov);
+		/* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
+		goto discard_and_relse;
+	}
+
+	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
+		goto discard_and_relse;
+
+	return sk_receive_skb(sk, skb, 1) ? -1 : 0;
+
+no_dccp_socket:
+	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
+		goto discard_it;
+	/*
+	 * Step 2:
+	 *	If no socket ...
+	 *		Generate Reset(No Connection) unless P.type == Reset
+	 *		Drop packet and return
+	 */
+	if (dh->dccph_type != DCCP_PKT_RESET) {
+		DCCP_SKB_CB(skb)->dccpd_reset_code =
+					DCCP_RESET_CODE_NO_CONNECTION;
+		dccp_v6_ctl_send_reset(sk, skb);
+	}
+
+discard_it:
+	kfree_skb(skb);
+	return 0;
+
+discard_and_relse:
+	sock_put(sk);
+	goto discard_it;
+}
+
+static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
+			   int addr_len)
+{
+	struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
+	struct inet_connection_sock *icsk = inet_csk(sk);
+	struct inet_sock *inet = inet_sk(sk);
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct in6_addr *saddr = NULL, *final_p = NULL, final;
+	struct flowi fl;
+	struct dst_entry *dst;
+	int addr_type;
+	int err;
+
+	dp->dccps_role = DCCP_ROLE_CLIENT;
+
+	if (addr_len < SIN6_LEN_RFC2133)
+		return -EINVAL;
+
+	if (usin->sin6_family != AF_INET6)
+		return -EAFNOSUPPORT;
+
+	memset(&fl, 0, sizeof(fl));
+
+	if (np->sndflow) {
+		fl.fl6_flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
+		IP6_ECN_flow_init(fl.fl6_flowlabel);
+		if (fl.fl6_flowlabel & IPV6_FLOWLABEL_MASK) {
+			struct ip6_flowlabel *flowlabel;
+			flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
+			if (flowlabel == NULL)
+				return -EINVAL;
+			ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
+			fl6_sock_release(flowlabel);
+		}
+	}
+	/*
+	 * connect() to INADDR_ANY means loopback (BSD'ism).
+	 */
+	if (ipv6_addr_any(&usin->sin6_addr))
+		usin->sin6_addr.s6_addr[15] = 1;
+
+	addr_type = ipv6_addr_type(&usin->sin6_addr);
+
+	if (addr_type & IPV6_ADDR_MULTICAST)
+		return -ENETUNREACH;
+
+	if (addr_type & IPV6_ADDR_LINKLOCAL) {
+		if (addr_len >= sizeof(struct sockaddr_in6) &&
+		    usin->sin6_scope_id) {
+			/* If interface is set while binding, indices
+			 * must coincide.
+			 */
+			if (sk->sk_bound_dev_if &&
+			    sk->sk_bound_dev_if != usin->sin6_scope_id)
+				return -EINVAL;
+
+			sk->sk_bound_dev_if = usin->sin6_scope_id;
+		}
+
+		/* Connect to link-local address requires an interface */
+		if (!sk->sk_bound_dev_if)
+			return -EINVAL;
+	}
+
+	ipv6_addr_copy(&np->daddr, &usin->sin6_addr);
+	np->flow_label = fl.fl6_flowlabel;
+
+	/*
+	 * DCCP over IPv4
+	 */
+	if (addr_type == IPV6_ADDR_MAPPED) {
+		u32 exthdrlen = icsk->icsk_ext_hdr_len;
+		struct sockaddr_in sin;
+
+		SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
+
+		if (__ipv6_only_sock(sk))
+			return -ENETUNREACH;
+
+		sin.sin_family = AF_INET;
+		sin.sin_port = usin->sin6_port;
+		sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
+
+		icsk->icsk_af_ops = &dccp_ipv6_mapped;
+		sk->sk_backlog_rcv = dccp_v4_do_rcv;
+
+		err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
+		if (err) {
+			icsk->icsk_ext_hdr_len = exthdrlen;
+			icsk->icsk_af_ops = &dccp_ipv6_af_ops;
+			sk->sk_backlog_rcv = dccp_v6_do_rcv;
+			goto failure;
+		} else {
+			ipv6_addr_set(&np->saddr, 0, 0, htonl(0x0000FFFF),
+				      inet->saddr);
+			ipv6_addr_set(&np->rcv_saddr, 0, 0, htonl(0x0000FFFF),
+				      inet->rcv_saddr);
+		}
+
+		return err;
+	}
+
+	if (!ipv6_addr_any(&np->rcv_saddr))
+		saddr = &np->rcv_saddr;
+
+	fl.proto = IPPROTO_DCCP;
+	ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
+	ipv6_addr_copy(&fl.fl6_src, saddr ? saddr : &np->saddr);
+	fl.oif = sk->sk_bound_dev_if;
+	fl.fl_ip_dport = usin->sin6_port;
+	fl.fl_ip_sport = inet->sport;
+	security_sk_classify_flow(sk, &fl);
+
+	if (np->opt != NULL && np->opt->srcrt != NULL) {
+		const struct rt0_hdr *rt0 = (struct rt0_hdr *)np->opt->srcrt;
+
+		ipv6_addr_copy(&final, &fl.fl6_dst);
+		ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
+		final_p = &final;
+	}
+
+	err = ip6_dst_lookup(sk, &dst, &fl);
+	if (err)
+		goto failure;
+
+	if (final_p)
+		ipv6_addr_copy(&fl.fl6_dst, final_p);
+
+	err = __xfrm_lookup(&dst, &fl, sk, XFRM_LOOKUP_WAIT);
+	if (err < 0) {
+		if (err == -EREMOTE)
+			err = ip6_dst_blackhole(sk, &dst, &fl);
+		if (err < 0)
+			goto failure;
+	}
+
+	if (saddr == NULL) {
+		saddr = &fl.fl6_src;
+		ipv6_addr_copy(&np->rcv_saddr, saddr);
+	}
+
+	/* set the source address */
+	ipv6_addr_copy(&np->saddr, saddr);
+	inet->rcv_saddr = LOOPBACK4_IPV6;
+
+	__ip6_dst_store(sk, dst, NULL, NULL);
+
+	icsk->icsk_ext_hdr_len = 0;
+	if (np->opt != NULL)
+		icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
+					  np->opt->opt_nflen);
+
+	inet->dport = usin->sin6_port;
+
+	dccp_set_state(sk, DCCP_REQUESTING);
+	err = inet6_hash_connect(&dccp_death_row, sk);
+	if (err)
+		goto late_failure;
+
+	dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
+						      np->daddr.s6_addr32,
+						      inet->sport, inet->dport);
+	err = dccp_connect(sk);
+	if (err)
+		goto late_failure;
+
+	return 0;
+
+late_failure:
+	dccp_set_state(sk, DCCP_CLOSED);
+	__sk_dst_reset(sk);
+failure:
+	inet->dport = 0;
+	sk->sk_route_caps = 0;
+	return err;
+}
+
+static struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
+	.queue_xmit	   = inet6_csk_xmit,
+	.send_check	   = dccp_v6_send_check,
+	.rebuild_header	   = inet6_sk_rebuild_header,
+	.conn_request	   = dccp_v6_conn_request,
+	.syn_recv_sock	   = dccp_v6_request_recv_sock,
+	.net_header_len	   = sizeof(struct ipv6hdr),
+	.setsockopt	   = ipv6_setsockopt,
+	.getsockopt	   = ipv6_getsockopt,
+	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
+	.sockaddr_len	   = sizeof(struct sockaddr_in6),
+	.bind_conflict	   = inet6_csk_bind_conflict,
+#ifdef CONFIG_COMPAT
+	.compat_setsockopt = compat_ipv6_setsockopt,
+	.compat_getsockopt = compat_ipv6_getsockopt,
+#endif
+};
+
+/*
+ *	DCCP over IPv4 via INET6 API
+ */
+static struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
+	.queue_xmit	   = ip_queue_xmit,
+	.send_check	   = dccp_v4_send_check,
+	.rebuild_header	   = inet_sk_rebuild_header,
+	.conn_request	   = dccp_v6_conn_request,
+	.syn_recv_sock	   = dccp_v6_request_recv_sock,
+	.net_header_len	   = sizeof(struct iphdr),
+	.setsockopt	   = ipv6_setsockopt,
+	.getsockopt	   = ipv6_getsockopt,
+	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
+	.sockaddr_len	   = sizeof(struct sockaddr_in6),
+#ifdef CONFIG_COMPAT
+	.compat_setsockopt = compat_ipv6_setsockopt,
+	.compat_getsockopt = compat_ipv6_getsockopt,
+#endif
+};
+
+/* NOTE: A lot of things set to zero explicitly by call to
+ *       sk_alloc() so need not be done here.
+ */
+static int dccp_v6_init_sock(struct sock *sk)
+{
+	static __u8 dccp_v6_ctl_sock_initialized;
+	int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);
+
+	if (err == 0) {
+		if (unlikely(!dccp_v6_ctl_sock_initialized))
+			dccp_v6_ctl_sock_initialized = 1;
+		inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
+	}
+
+	return err;
+}
+
+static void dccp_v6_destroy_sock(struct sock *sk)
+{
+	dccp_destroy_sock(sk);
+	inet6_destroy_sock(sk);
+}
+
+static struct timewait_sock_ops dccp6_timewait_sock_ops = {
+	.twsk_obj_size	= sizeof(struct dccp6_timewait_sock),
+};
+
+static struct proto dccp_v6_prot = {
+	.name		   = "DCCPv6",
+	.owner		   = THIS_MODULE,
+	.close		   = dccp_close,
+	.connect	   = dccp_v6_connect,
+	.disconnect	   = dccp_disconnect,
+	.ioctl		   = dccp_ioctl,
+	.init		   = dccp_v6_init_sock,
+	.setsockopt	   = dccp_setsockopt,
+	.getsockopt	   = dccp_getsockopt,
+	.sendmsg	   = dccp_sendmsg,
+	.recvmsg	   = dccp_recvmsg,
+	.backlog_rcv	   = dccp_v6_do_rcv,
+	.hash		   = dccp_v6_hash,
+	.unhash		   = inet_unhash,
+	.accept		   = inet_csk_accept,
+	.get_port	   = inet_csk_get_port,
+	.shutdown	   = dccp_shutdown,
+	.destroy	   = dccp_v6_destroy_sock,
+	.orphan_count	   = &dccp_orphan_count,
+	.max_header	   = MAX_DCCP_HEADER,
+	.obj_size	   = sizeof(struct dccp6_sock),
+	.rsk_prot	   = &dccp6_request_sock_ops,
+	.twsk_prot	   = &dccp6_timewait_sock_ops,
+	.h.hashinfo	   = &dccp_hashinfo,
+#ifdef CONFIG_COMPAT
+	.compat_setsockopt = compat_dccp_setsockopt,
+	.compat_getsockopt = compat_dccp_getsockopt,
+#endif
+};
+
+static struct inet6_protocol dccp_v6_protocol = {
+	.handler	= dccp_v6_rcv,
+	.err_handler	= dccp_v6_err,
+	.flags		= INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
+};
+
+static struct proto_ops inet6_dccp_ops = {
+	.family		   = PF_INET6,
+	.owner		   = THIS_MODULE,
+	.release	   = inet6_release,
+	.bind		   = inet6_bind,
+	.connect	   = inet_stream_connect,
+	.socketpair	   = sock_no_socketpair,
+	.accept		   = inet_accept,
+	.getname	   = inet6_getname,
+	.poll		   = dccp_poll,
+	.ioctl		   = inet6_ioctl,
+	.listen		   = inet_dccp_listen,
+	.shutdown	   = inet_shutdown,
+	.setsockopt	   = sock_common_setsockopt,
+	.getsockopt	   = sock_common_getsockopt,
+	.sendmsg	   = inet_sendmsg,
+	.recvmsg	   = sock_common_recvmsg,
+	.mmap		   = sock_no_mmap,
+	.sendpage	   = sock_no_sendpage,
+#ifdef CONFIG_COMPAT
+	.compat_setsockopt = compat_sock_common_setsockopt,
+	.compat_getsockopt = compat_sock_common_getsockopt,
+#endif
+};
+
+static struct inet_protosw dccp_v6_protosw = {
+	.type		= SOCK_DCCP,
+	.protocol	= IPPROTO_DCCP,
+	.prot		= &dccp_v6_prot,
+	.ops		= &inet6_dccp_ops,
+	.capability	= -1,
+	.flags		= INET_PROTOSW_ICSK,
+};
+
+static int dccp_v6_init_net(struct net *net)
+{
+	int err;
+
+	err = inet_ctl_sock_create(&net->dccp.v6_ctl_sk, PF_INET6,
+				   SOCK_DCCP, IPPROTO_DCCP, net);
+	return err;
+}
+
+static void dccp_v6_exit_net(struct net *net)
+{
+	inet_ctl_sock_destroy(net->dccp.v6_ctl_sk);
+}
+
+static struct pernet_operations dccp_v6_ops = {
+	.init   = dccp_v6_init_net,
+	.exit   = dccp_v6_exit_net,
+};
+
+static int __init dccp_v6_init(void)
+{
+	int err = proto_register(&dccp_v6_prot, 1);
+
+	if (err != 0)
+		goto out;
+
+	err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
+	if (err != 0)
+		goto out_unregister_proto;
+
+	inet6_register_protosw(&dccp_v6_protosw);
+
+	err = register_pernet_subsys(&dccp_v6_ops);
+	if (err != 0)
+		goto out_destroy_ctl_sock;
+out:
+	return err;
+
+out_destroy_ctl_sock:
+	inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
+	inet6_unregister_protosw(&dccp_v6_protosw);
+out_unregister_proto:
+	proto_unregister(&dccp_v6_prot);
+	goto out;
+}
+
+static void __exit dccp_v6_exit(void)
+{
+	unregister_pernet_subsys(&dccp_v6_ops);
+	inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
+	inet6_unregister_protosw(&dccp_v6_protosw);
+	proto_unregister(&dccp_v6_prot);
+}
+
+module_init(dccp_v6_init);
+module_exit(dccp_v6_exit);
+
+/*
+ * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
+ * values directly, Also cover the case where the protocol is not specified,
+ * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
+ */
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
+MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
+MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");
diff --git a/net/dccp/ipv6.h b/net/dccp/ipv6.h
new file mode 100644
index 0000000..6eef81f
--- /dev/null
+++ b/net/dccp/ipv6.h
@@ -0,0 +1,36 @@
+#ifndef _DCCP_IPV6_H
+#define _DCCP_IPV6_H
+/*
+ *  net/dccp/ipv6.h
+ *
+ *  An implementation of the DCCP protocol
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
+ *
+ *	This program is free software; you can redistribute it and/or modify it
+ *	under the terms of the GNU General Public License version 2 as
+ *	published by the Free Software Foundation.
+ */
+
+#include <linux/dccp.h>
+#include <linux/ipv6.h>
+
+struct dccp6_sock {
+	struct dccp_sock  dccp;
+	/*
+	 * ipv6_pinfo has to be the last member of dccp6_sock,
+	 * see inet6_sk_generic.
+	 */
+	struct ipv6_pinfo inet6;
+};
+
+struct dccp6_request_sock {
+	struct dccp_request_sock  dccp;
+	struct inet6_request_sock inet6;
+};
+
+struct dccp6_timewait_sock {
+	struct inet_timewait_sock   inet;
+	struct inet6_timewait_sock  tw6;
+};
+
+#endif /* _DCCP_IPV6_H */
diff --git a/net/dccp/minisocks.c b/net/dccp/minisocks.c
new file mode 100644
index 0000000..e6bf99e
--- /dev/null
+++ b/net/dccp/minisocks.c
@@ -0,0 +1,318 @@
+/*
+ *  net/dccp/minisocks.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/dccp.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/timer.h>
+
+#include <net/sock.h>
+#include <net/xfrm.h>
+#include <net/inet_timewait_sock.h>
+
+#include "ackvec.h"
+#include "ccid.h"
+#include "dccp.h"
+#include "feat.h"
+
+struct inet_timewait_death_row dccp_death_row = {
+	.sysctl_max_tw_buckets = NR_FILE * 2,
+	.period		= DCCP_TIMEWAIT_LEN / INET_TWDR_TWKILL_SLOTS,
+	.death_lock	= __SPIN_LOCK_UNLOCKED(dccp_death_row.death_lock),
+	.hashinfo	= &dccp_hashinfo,
+	.tw_timer	= TIMER_INITIALIZER(inet_twdr_hangman, 0,
+					    (unsigned long)&dccp_death_row),
+	.twkill_work	= __WORK_INITIALIZER(dccp_death_row.twkill_work,
+					     inet_twdr_twkill_work),
+/* Short-time timewait calendar */
+
+	.twcal_hand	= -1,
+	.twcal_timer	= TIMER_INITIALIZER(inet_twdr_twcal_tick, 0,
+					    (unsigned long)&dccp_death_row),
+};
+
+EXPORT_SYMBOL_GPL(dccp_death_row);
+
+void dccp_minisock_init(struct dccp_minisock *dmsk)
+{
+	dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window;
+	dmsk->dccpms_rx_ccid	     = sysctl_dccp_feat_rx_ccid;
+	dmsk->dccpms_tx_ccid	     = sysctl_dccp_feat_tx_ccid;
+	dmsk->dccpms_ack_ratio	     = sysctl_dccp_feat_ack_ratio;
+	dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector;
+	dmsk->dccpms_send_ndp_count  = sysctl_dccp_feat_send_ndp_count;
+}
+
+void dccp_time_wait(struct sock *sk, int state, int timeo)
+{
+	struct inet_timewait_sock *tw = NULL;
+
+	if (dccp_death_row.tw_count < dccp_death_row.sysctl_max_tw_buckets)
+		tw = inet_twsk_alloc(sk, state);
+
+	if (tw != NULL) {
+		const struct inet_connection_sock *icsk = inet_csk(sk);
+		const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+		if (tw->tw_family == PF_INET6) {
+			const struct ipv6_pinfo *np = inet6_sk(sk);
+			struct inet6_timewait_sock *tw6;
+
+			tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot);
+			tw6 = inet6_twsk((struct sock *)tw);
+			ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr);
+			ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr);
+			tw->tw_ipv6only = np->ipv6only;
+		}
+#endif
+		/* Linkage updates. */
+		__inet_twsk_hashdance(tw, sk, &dccp_hashinfo);
+
+		/* Get the TIME_WAIT timeout firing. */
+		if (timeo < rto)
+			timeo = rto;
+
+		tw->tw_timeout = DCCP_TIMEWAIT_LEN;
+		if (state == DCCP_TIME_WAIT)
+			timeo = DCCP_TIMEWAIT_LEN;
+
+		inet_twsk_schedule(tw, &dccp_death_row, timeo,
+				   DCCP_TIMEWAIT_LEN);
+		inet_twsk_put(tw);
+	} else {
+		/* Sorry, if we're out of memory, just CLOSE this
+		 * socket up.  We've got bigger problems than
+		 * non-graceful socket closings.
+		 */
+		DCCP_WARN("time wait bucket table overflow\n");
+	}
+
+	dccp_done(sk);
+}
+
+struct sock *dccp_create_openreq_child(struct sock *sk,
+				       const struct request_sock *req,
+				       const struct sk_buff *skb)
+{
+	/*
+	 * Step 3: Process LISTEN state
+	 *
+	 *   (* Generate a new socket and switch to that socket *)
+	 *   Set S := new socket for this port pair
+	 */
+	struct sock *newsk = inet_csk_clone(sk, req, GFP_ATOMIC);
+
+	if (newsk != NULL) {
+		const struct dccp_request_sock *dreq = dccp_rsk(req);
+		struct inet_connection_sock *newicsk = inet_csk(newsk);
+		struct dccp_sock *newdp = dccp_sk(newsk);
+		struct dccp_minisock *newdmsk = dccp_msk(newsk);
+
+		newdp->dccps_role	    = DCCP_ROLE_SERVER;
+		newdp->dccps_hc_rx_ackvec   = NULL;
+		newdp->dccps_service_list   = NULL;
+		newdp->dccps_service	    = dreq->dreq_service;
+		newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo;
+		newdp->dccps_timestamp_time = dreq->dreq_timestamp_time;
+		newicsk->icsk_rto	    = DCCP_TIMEOUT_INIT;
+
+		if (dccp_feat_clone(sk, newsk))
+			goto out_free;
+
+		if (newdmsk->dccpms_send_ack_vector) {
+			newdp->dccps_hc_rx_ackvec =
+						dccp_ackvec_alloc(GFP_ATOMIC);
+			if (unlikely(newdp->dccps_hc_rx_ackvec == NULL))
+				goto out_free;
+		}
+
+		newdp->dccps_hc_rx_ccid =
+			    ccid_hc_rx_new(newdmsk->dccpms_rx_ccid,
+					   newsk, GFP_ATOMIC);
+		newdp->dccps_hc_tx_ccid =
+			    ccid_hc_tx_new(newdmsk->dccpms_tx_ccid,
+					   newsk, GFP_ATOMIC);
+		if (unlikely(newdp->dccps_hc_rx_ccid == NULL ||
+			     newdp->dccps_hc_tx_ccid == NULL)) {
+			dccp_ackvec_free(newdp->dccps_hc_rx_ackvec);
+			ccid_hc_rx_delete(newdp->dccps_hc_rx_ccid, newsk);
+			ccid_hc_tx_delete(newdp->dccps_hc_tx_ccid, newsk);
+out_free:
+			/* It is still raw copy of parent, so invalidate
+			 * destructor and make plain sk_free() */
+			newsk->sk_destruct = NULL;
+			sk_free(newsk);
+			return NULL;
+		}
+
+		/*
+		 * Step 3: Process LISTEN state
+		 *
+		 *    Choose S.ISS (initial seqno) or set from Init Cookies
+		 *    Initialize S.GAR := S.ISS
+		 *    Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookies
+		 */
+
+		/* See dccp_v4_conn_request */
+		newdmsk->dccpms_sequence_window = req->rcv_wnd;
+
+		newdp->dccps_gar = newdp->dccps_iss = dreq->dreq_iss;
+		dccp_update_gss(newsk, dreq->dreq_iss);
+
+		newdp->dccps_isr = dreq->dreq_isr;
+		dccp_update_gsr(newsk, dreq->dreq_isr);
+
+		/*
+		 * SWL and AWL are initially adjusted so that they are not less than
+		 * the initial Sequence Numbers received and sent, respectively:
+		 *	SWL := max(GSR + 1 - floor(W/4), ISR),
+		 *	AWL := max(GSS - W' + 1, ISS).
+		 * These adjustments MUST be applied only at the beginning of the
+		 * connection.
+		 */
+		dccp_set_seqno(&newdp->dccps_swl,
+			       max48(newdp->dccps_swl, newdp->dccps_isr));
+		dccp_set_seqno(&newdp->dccps_awl,
+			       max48(newdp->dccps_awl, newdp->dccps_iss));
+
+		dccp_init_xmit_timers(newsk);
+
+		DCCP_INC_STATS_BH(DCCP_MIB_PASSIVEOPENS);
+	}
+	return newsk;
+}
+
+EXPORT_SYMBOL_GPL(dccp_create_openreq_child);
+
+/*
+ * Process an incoming packet for RESPOND sockets represented
+ * as an request_sock.
+ */
+struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
+			    struct request_sock *req,
+			    struct request_sock **prev)
+{
+	struct sock *child = NULL;
+	struct dccp_request_sock *dreq = dccp_rsk(req);
+
+	/* Check for retransmitted REQUEST */
+	if (dccp_hdr(skb)->dccph_type == DCCP_PKT_REQUEST) {
+
+		if (after48(DCCP_SKB_CB(skb)->dccpd_seq, dreq->dreq_isr)) {
+			dccp_pr_debug("Retransmitted REQUEST\n");
+			dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
+			/*
+			 * Send another RESPONSE packet
+			 * To protect against Request floods, increment retrans
+			 * counter (backoff, monitored by dccp_response_timer).
+			 */
+			req->retrans++;
+			req->rsk_ops->rtx_syn_ack(sk, req);
+		}
+		/* Network Duplicate, discard packet */
+		return NULL;
+	}
+
+	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
+
+	if (dccp_hdr(skb)->dccph_type != DCCP_PKT_ACK &&
+	    dccp_hdr(skb)->dccph_type != DCCP_PKT_DATAACK)
+		goto drop;
+
+	/* Invalid ACK */
+	if (DCCP_SKB_CB(skb)->dccpd_ack_seq != dreq->dreq_iss) {
+		dccp_pr_debug("Invalid ACK number: ack_seq=%llu, "
+			      "dreq_iss=%llu\n",
+			      (unsigned long long)
+			      DCCP_SKB_CB(skb)->dccpd_ack_seq,
+			      (unsigned long long) dreq->dreq_iss);
+		goto drop;
+	}
+
+	if (dccp_parse_options(sk, dreq, skb))
+		 goto drop;
+
+	child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
+	if (child == NULL)
+		goto listen_overflow;
+
+	inet_csk_reqsk_queue_unlink(sk, req, prev);
+	inet_csk_reqsk_queue_removed(sk, req);
+	inet_csk_reqsk_queue_add(sk, req, child);
+out:
+	return child;
+listen_overflow:
+	dccp_pr_debug("listen_overflow!\n");
+	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_TOO_BUSY;
+drop:
+	if (dccp_hdr(skb)->dccph_type != DCCP_PKT_RESET)
+		req->rsk_ops->send_reset(sk, skb);
+
+	inet_csk_reqsk_queue_drop(sk, req, prev);
+	goto out;
+}
+
+EXPORT_SYMBOL_GPL(dccp_check_req);
+
+/*
+ *  Queue segment on the new socket if the new socket is active,
+ *  otherwise we just shortcircuit this and continue with
+ *  the new socket.
+ */
+int dccp_child_process(struct sock *parent, struct sock *child,
+		       struct sk_buff *skb)
+{
+	int ret = 0;
+	const int state = child->sk_state;
+
+	if (!sock_owned_by_user(child)) {
+		ret = dccp_rcv_state_process(child, skb, dccp_hdr(skb),
+					     skb->len);
+
+		/* Wakeup parent, send SIGIO */
+		if (state == DCCP_RESPOND && child->sk_state != state)
+			parent->sk_data_ready(parent, 0);
+	} else {
+		/* Alas, it is possible again, because we do lookup
+		 * in main socket hash table and lock on listening
+		 * socket does not protect us more.
+		 */
+		sk_add_backlog(child, skb);
+	}
+
+	bh_unlock_sock(child);
+	sock_put(child);
+	return ret;
+}
+
+EXPORT_SYMBOL_GPL(dccp_child_process);
+
+void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
+			 struct request_sock *rsk)
+{
+	DCCP_BUG("DCCP-ACK packets are never sent in LISTEN/RESPOND state");
+}
+
+EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);
+
+void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb)
+{
+	struct dccp_request_sock *dreq = dccp_rsk(req);
+
+	inet_rsk(req)->rmt_port	  = dccp_hdr(skb)->dccph_sport;
+	inet_rsk(req)->loc_port	  = dccp_hdr(skb)->dccph_dport;
+	inet_rsk(req)->acked	  = 0;
+	req->rcv_wnd		  = sysctl_dccp_feat_sequence_window;
+	dreq->dreq_timestamp_echo = 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_reqsk_init);
diff --git a/net/dccp/options.c b/net/dccp/options.c
new file mode 100644
index 0000000..0809b63
--- /dev/null
+++ b/net/dccp/options.c
@@ -0,0 +1,622 @@
+/*
+ *  net/dccp/options.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Copyright (c) 2005 Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
+ *  Copyright (c) 2005 Ian McDonald <ian.mcdonald@jandi.co.nz>
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+#include <linux/dccp.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <asm/unaligned.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+
+#include "ackvec.h"
+#include "ccid.h"
+#include "dccp.h"
+#include "feat.h"
+
+int sysctl_dccp_feat_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW;
+int sysctl_dccp_feat_rx_ccid	      = DCCPF_INITIAL_CCID;
+int sysctl_dccp_feat_tx_ccid	      = DCCPF_INITIAL_CCID;
+int sysctl_dccp_feat_ack_ratio	      = DCCPF_INITIAL_ACK_RATIO;
+int sysctl_dccp_feat_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR;
+int sysctl_dccp_feat_send_ndp_count  = DCCPF_INITIAL_SEND_NDP_COUNT;
+
+static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
+{
+	u32 value = 0;
+
+	if (len > 3)
+		value += *bf++ << 24;
+	if (len > 2)
+		value += *bf++ << 16;
+	if (len > 1)
+		value += *bf++ << 8;
+	if (len > 0)
+		value += *bf;
+
+	return value;
+}
+
+/**
+ * dccp_parse_options  -  Parse DCCP options present in @skb
+ * @sk: client|server|listening dccp socket (when @dreq != NULL)
+ * @dreq: request socket to use during connection setup, or NULL
+ */
+int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
+		       struct sk_buff *skb)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	const struct dccp_hdr *dh = dccp_hdr(skb);
+	const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
+	u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
+	unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
+	unsigned char *opt_ptr = options;
+	const unsigned char *opt_end = (unsigned char *)dh +
+					(dh->dccph_doff * 4);
+	struct dccp_options_received *opt_recv = &dp->dccps_options_received;
+	unsigned char opt, len;
+	unsigned char *value;
+	u32 elapsed_time;
+	__be32 opt_val;
+	int rc;
+	int mandatory = 0;
+
+	memset(opt_recv, 0, sizeof(*opt_recv));
+
+	opt = len = 0;
+	while (opt_ptr != opt_end) {
+		opt   = *opt_ptr++;
+		len   = 0;
+		value = NULL;
+
+		/* Check if this isn't a single byte option */
+		if (opt > DCCPO_MAX_RESERVED) {
+			if (opt_ptr == opt_end)
+				goto out_nonsensical_length;
+
+			len = *opt_ptr++;
+			if (len < 2)
+				goto out_nonsensical_length;
+			/*
+			 * Remove the type and len fields, leaving
+			 * just the value size
+			 */
+			len	-= 2;
+			value	= opt_ptr;
+			opt_ptr += len;
+
+			if (opt_ptr > opt_end)
+				goto out_nonsensical_length;
+		}
+
+		/*
+		 * CCID-Specific Options (from RFC 4340, sec. 10.3):
+		 *
+		 * Option numbers 128 through 191 are for options sent from the
+		 * HC-Sender to the HC-Receiver; option numbers 192 through 255
+		 * are for options sent from the HC-Receiver to	the HC-Sender.
+		 *
+		 * CCID-specific options are ignored during connection setup, as
+		 * negotiation may still be in progress (see RFC 4340, 10.3).
+		 * The same applies to Ack Vectors, as these depend on the CCID.
+		 *
+		 */
+		if (dreq != NULL && (opt >= 128 ||
+		    opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1))
+			goto ignore_option;
+
+		switch (opt) {
+		case DCCPO_PADDING:
+			break;
+		case DCCPO_MANDATORY:
+			if (mandatory)
+				goto out_invalid_option;
+			if (pkt_type != DCCP_PKT_DATA)
+				mandatory = 1;
+			break;
+		case DCCPO_NDP_COUNT:
+			if (len > 6)
+				goto out_invalid_option;
+
+			opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
+			dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
+				      (unsigned long long)opt_recv->dccpor_ndp);
+			break;
+		case DCCPO_CHANGE_L:
+			/* fall through */
+		case DCCPO_CHANGE_R:
+			if (pkt_type == DCCP_PKT_DATA)
+				break;
+			if (len < 2)
+				goto out_invalid_option;
+			rc = dccp_feat_change_recv(sk, opt, *value, value + 1,
+						   len - 1);
+			/*
+			 * When there is a change error, change_recv is
+			 * responsible for dealing with it.  i.e. reply with an
+			 * empty confirm.
+			 * If the change was mandatory, then we need to die.
+			 */
+			if (rc && mandatory)
+				goto out_invalid_option;
+			break;
+		case DCCPO_CONFIRM_L:
+			/* fall through */
+		case DCCPO_CONFIRM_R:
+			if (pkt_type == DCCP_PKT_DATA)
+				break;
+			if (len < 2)	/* FIXME this disallows empty confirm */
+				goto out_invalid_option;
+			if (dccp_feat_confirm_recv(sk, opt, *value,
+						   value + 1, len - 1))
+				goto out_invalid_option;
+			break;
+		case DCCPO_ACK_VECTOR_0:
+		case DCCPO_ACK_VECTOR_1:
+			if (dccp_packet_without_ack(skb))   /* RFC 4340, 11.4 */
+				break;
+
+			if (dccp_msk(sk)->dccpms_send_ack_vector &&
+			    dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
+				goto out_invalid_option;
+			break;
+		case DCCPO_TIMESTAMP:
+			if (len != 4)
+				goto out_invalid_option;
+			/*
+			 * RFC 4340 13.1: "The precise time corresponding to
+			 * Timestamp Value zero is not specified". We use
+			 * zero to indicate absence of a meaningful timestamp.
+			 */
+			opt_val = get_unaligned((__be32 *)value);
+			if (unlikely(opt_val == 0)) {
+				DCCP_WARN("Timestamp with zero value\n");
+				break;
+			}
+
+			if (dreq != NULL) {
+				dreq->dreq_timestamp_echo = ntohl(opt_val);
+				dreq->dreq_timestamp_time = dccp_timestamp();
+			} else {
+				opt_recv->dccpor_timestamp =
+					dp->dccps_timestamp_echo = ntohl(opt_val);
+				dp->dccps_timestamp_time = dccp_timestamp();
+			}
+			dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
+				      dccp_role(sk), ntohl(opt_val),
+				      (unsigned long long)
+				      DCCP_SKB_CB(skb)->dccpd_ack_seq);
+			break;
+		case DCCPO_TIMESTAMP_ECHO:
+			if (len != 4 && len != 6 && len != 8)
+				goto out_invalid_option;
+
+			opt_val = get_unaligned((__be32 *)value);
+			opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
+
+			dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
+				      "ackno=%llu", dccp_role(sk),
+				      opt_recv->dccpor_timestamp_echo,
+				      len + 2,
+				      (unsigned long long)
+				      DCCP_SKB_CB(skb)->dccpd_ack_seq);
+
+			value += 4;
+
+			if (len == 4) {		/* no elapsed time included */
+				dccp_pr_debug_cat("\n");
+				break;
+			}
+
+			if (len == 6) {		/* 2-byte elapsed time */
+				__be16 opt_val2 = get_unaligned((__be16 *)value);
+				elapsed_time = ntohs(opt_val2);
+			} else {		/* 4-byte elapsed time */
+				opt_val = get_unaligned((__be32 *)value);
+				elapsed_time = ntohl(opt_val);
+			}
+
+			dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
+
+			/* Give precedence to the biggest ELAPSED_TIME */
+			if (elapsed_time > opt_recv->dccpor_elapsed_time)
+				opt_recv->dccpor_elapsed_time = elapsed_time;
+			break;
+		case DCCPO_ELAPSED_TIME:
+			if (dccp_packet_without_ack(skb))   /* RFC 4340, 13.2 */
+				break;
+
+			if (len == 2) {
+				__be16 opt_val2 = get_unaligned((__be16 *)value);
+				elapsed_time = ntohs(opt_val2);
+			} else if (len == 4) {
+				opt_val = get_unaligned((__be32 *)value);
+				elapsed_time = ntohl(opt_val);
+			} else {
+				goto out_invalid_option;
+			}
+
+			if (elapsed_time > opt_recv->dccpor_elapsed_time)
+				opt_recv->dccpor_elapsed_time = elapsed_time;
+
+			dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
+				      dccp_role(sk), elapsed_time);
+			break;
+		case 128 ... 191: {
+			const u16 idx = value - options;
+
+			if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
+						     opt, len, idx,
+						     value) != 0)
+				goto out_invalid_option;
+		}
+			break;
+		case 192 ... 255: {
+			const u16 idx = value - options;
+
+			if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
+						     opt, len, idx,
+						     value) != 0)
+				goto out_invalid_option;
+		}
+			break;
+		default:
+			DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
+				  "implemented, ignoring", sk, opt, len);
+			break;
+		}
+ignore_option:
+		if (opt != DCCPO_MANDATORY)
+			mandatory = 0;
+	}
+
+	/* mandatory was the last byte in option list -> reset connection */
+	if (mandatory)
+		goto out_invalid_option;
+
+out_nonsensical_length:
+	/* RFC 4340, 5.8: ignore option and all remaining option space */
+	return 0;
+
+out_invalid_option:
+	DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
+	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
+	DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len);
+	DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
+	DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
+	DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;
+	return -1;
+}
+
+EXPORT_SYMBOL_GPL(dccp_parse_options);
+
+static void dccp_encode_value_var(const u32 value, unsigned char *to,
+				  const unsigned int len)
+{
+	if (len > 3)
+		*to++ = (value & 0xFF000000) >> 24;
+	if (len > 2)
+		*to++ = (value & 0xFF0000) >> 16;
+	if (len > 1)
+		*to++ = (value & 0xFF00) >> 8;
+	if (len > 0)
+		*to++ = (value & 0xFF);
+}
+
+static inline u8 dccp_ndp_len(const u64 ndp)
+{
+	if (likely(ndp <= 0xFF))
+		return 1;
+	return likely(ndp <= USHORT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6);
+}
+
+int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
+			const unsigned char option,
+			const void *value, const unsigned char len)
+{
+	unsigned char *to;
+
+	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
+		return -1;
+
+	DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
+
+	to    = skb_push(skb, len + 2);
+	*to++ = option;
+	*to++ = len + 2;
+
+	memcpy(to, value, len);
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_insert_option);
+
+static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	u64 ndp = dp->dccps_ndp_count;
+
+	if (dccp_non_data_packet(skb))
+		++dp->dccps_ndp_count;
+	else
+		dp->dccps_ndp_count = 0;
+
+	if (ndp > 0) {
+		unsigned char *ptr;
+		const int ndp_len = dccp_ndp_len(ndp);
+		const int len = ndp_len + 2;
+
+		if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
+			return -1;
+
+		DCCP_SKB_CB(skb)->dccpd_opt_len += len;
+
+		ptr = skb_push(skb, len);
+		*ptr++ = DCCPO_NDP_COUNT;
+		*ptr++ = len;
+		dccp_encode_value_var(ndp, ptr, ndp_len);
+	}
+
+	return 0;
+}
+
+static inline int dccp_elapsed_time_len(const u32 elapsed_time)
+{
+	return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
+}
+
+int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
+				    u32 elapsed_time)
+{
+	const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
+	const int len = 2 + elapsed_time_len;
+	unsigned char *to;
+
+	if (elapsed_time_len == 0)
+		return 0;
+
+	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
+		return -1;
+
+	DCCP_SKB_CB(skb)->dccpd_opt_len += len;
+
+	to    = skb_push(skb, len);
+	*to++ = DCCPO_ELAPSED_TIME;
+	*to++ = len;
+
+	if (elapsed_time_len == 2) {
+		const __be16 var16 = htons((u16)elapsed_time);
+		memcpy(to, &var16, 2);
+	} else {
+		const __be32 var32 = htonl(elapsed_time);
+		memcpy(to, &var32, 4);
+	}
+
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
+
+int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
+{
+	__be32 now = htonl(dccp_timestamp());
+	/* yes this will overflow but that is the point as we want a
+	 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
+
+	return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
+}
+
+EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
+
+static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
+					     struct dccp_request_sock *dreq,
+					     struct sk_buff *skb)
+{
+	__be32 tstamp_echo;
+	unsigned char *to;
+	u32 elapsed_time, elapsed_time_len, len;
+
+	if (dreq != NULL) {
+		elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
+		tstamp_echo  = htonl(dreq->dreq_timestamp_echo);
+		dreq->dreq_timestamp_echo = 0;
+	} else {
+		elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
+		tstamp_echo  = htonl(dp->dccps_timestamp_echo);
+		dp->dccps_timestamp_echo = 0;
+	}
+
+	elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
+	len = 6 + elapsed_time_len;
+
+	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
+		return -1;
+
+	DCCP_SKB_CB(skb)->dccpd_opt_len += len;
+
+	to    = skb_push(skb, len);
+	*to++ = DCCPO_TIMESTAMP_ECHO;
+	*to++ = len;
+
+	memcpy(to, &tstamp_echo, 4);
+	to += 4;
+
+	if (elapsed_time_len == 2) {
+		const __be16 var16 = htons((u16)elapsed_time);
+		memcpy(to, &var16, 2);
+	} else if (elapsed_time_len == 4) {
+		const __be32 var32 = htonl(elapsed_time);
+		memcpy(to, &var32, 4);
+	}
+
+	return 0;
+}
+
+static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
+				u8 *val, u8 len)
+{
+	u8 *to;
+
+	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
+		DCCP_WARN("packet too small for feature %d option!\n", feat);
+		return -1;
+	}
+
+	DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
+
+	to    = skb_push(skb, len + 3);
+	*to++ = type;
+	*to++ = len + 3;
+	*to++ = feat;
+
+	if (len)
+		memcpy(to, val, len);
+
+	dccp_pr_debug("%s(%s (%d), ...), length %d\n",
+		      dccp_feat_typename(type),
+		      dccp_feat_name(feat), feat, len);
+	return 0;
+}
+
+static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct dccp_minisock *dmsk = dccp_msk(sk);
+	struct dccp_opt_pend *opt, *next;
+	int change = 0;
+
+	/* confirm any options [NN opts] */
+	list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
+		dccp_insert_feat_opt(skb, opt->dccpop_type,
+				     opt->dccpop_feat, opt->dccpop_val,
+				     opt->dccpop_len);
+		/* fear empty confirms */
+		if (opt->dccpop_val)
+			kfree(opt->dccpop_val);
+		kfree(opt);
+	}
+	INIT_LIST_HEAD(&dmsk->dccpms_conf);
+
+	/* see which features we need to send */
+	list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
+		/* see if we need to send any confirm */
+		if (opt->dccpop_sc) {
+			dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
+					     opt->dccpop_feat,
+					     opt->dccpop_sc->dccpoc_val,
+					     opt->dccpop_sc->dccpoc_len);
+
+			BUG_ON(!opt->dccpop_sc->dccpoc_val);
+			kfree(opt->dccpop_sc->dccpoc_val);
+			kfree(opt->dccpop_sc);
+			opt->dccpop_sc = NULL;
+		}
+
+		/* any option not confirmed, re-send it */
+		if (!opt->dccpop_conf) {
+			dccp_insert_feat_opt(skb, opt->dccpop_type,
+					     opt->dccpop_feat, opt->dccpop_val,
+					     opt->dccpop_len);
+			change++;
+		}
+	}
+
+	/* Retransmit timer.
+	 * If this is the master listening sock, we don't set a timer on it.  It
+	 * should be fine because if the dude doesn't receive our RESPONSE
+	 * [which will contain the CHANGE] he will send another REQUEST which
+	 * will "retrnasmit" the change.
+	 */
+	if (change && dp->dccps_role != DCCP_ROLE_LISTEN) {
+		dccp_pr_debug("reset feat negotiation timer %p\n", sk);
+
+		/* XXX don't reset the timer on re-transmissions.  I.e. reset it
+		 * only when sending new stuff i guess.  Currently the timer
+		 * never backs off because on re-transmission it just resets it!
+		 */
+		inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+					  inet_csk(sk)->icsk_rto, DCCP_RTO_MAX);
+	}
+
+	return 0;
+}
+
+/* The length of all options needs to be a multiple of 4 (5.8) */
+static void dccp_insert_option_padding(struct sk_buff *skb)
+{
+	int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
+
+	if (padding != 0) {
+		padding = 4 - padding;
+		memset(skb_push(skb, padding), 0, padding);
+		DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
+	}
+}
+
+int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct dccp_minisock *dmsk = dccp_msk(sk);
+
+	DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
+
+	if (dmsk->dccpms_send_ndp_count &&
+	    dccp_insert_option_ndp(sk, skb))
+		return -1;
+
+	if (!dccp_packet_without_ack(skb)) {
+		if (dmsk->dccpms_send_ack_vector &&
+		    dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
+		    dccp_insert_option_ackvec(sk, skb))
+			return -1;
+	}
+
+	if (dp->dccps_hc_rx_insert_options) {
+		if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
+			return -1;
+		dp->dccps_hc_rx_insert_options = 0;
+	}
+
+	/* Feature negotiation */
+	/* Data packets can't do feat negotiation */
+	if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
+	    DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
+	    dccp_insert_options_feat(sk, skb))
+		return -1;
+
+	/*
+	 * Obtain RTT sample from Request/Response exchange.
+	 * This is currently used in CCID 3 initialisation.
+	 */
+	if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST &&
+	    dccp_insert_option_timestamp(sk, skb))
+		return -1;
+
+	if (dp->dccps_timestamp_echo != 0 &&
+	    dccp_insert_option_timestamp_echo(dp, NULL, skb))
+		return -1;
+
+	dccp_insert_option_padding(skb);
+	return 0;
+}
+
+int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
+{
+	DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
+
+	if (dreq->dreq_timestamp_echo != 0 &&
+	    dccp_insert_option_timestamp_echo(NULL, dreq, skb))
+		return -1;
+
+	dccp_insert_option_padding(skb);
+	return 0;
+}
diff --git a/net/dccp/output.c b/net/dccp/output.c
new file mode 100644
index 0000000..809d803
--- /dev/null
+++ b/net/dccp/output.c
@@ -0,0 +1,619 @@
+/*
+ *  net/dccp/output.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/dccp.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+
+#include <net/inet_sock.h>
+#include <net/sock.h>
+
+#include "ackvec.h"
+#include "ccid.h"
+#include "dccp.h"
+
+static inline void dccp_event_ack_sent(struct sock *sk)
+{
+	inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
+}
+
+static void dccp_skb_entail(struct sock *sk, struct sk_buff *skb)
+{
+	skb_set_owner_w(skb, sk);
+	WARN_ON(sk->sk_send_head);
+	sk->sk_send_head = skb;
+}
+
+/*
+ * All SKB's seen here are completely headerless. It is our
+ * job to build the DCCP header, and pass the packet down to
+ * IP so it can do the same plus pass the packet off to the
+ * device.
+ */
+static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
+{
+	if (likely(skb != NULL)) {
+		const struct inet_sock *inet = inet_sk(sk);
+		const struct inet_connection_sock *icsk = inet_csk(sk);
+		struct dccp_sock *dp = dccp_sk(sk);
+		struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
+		struct dccp_hdr *dh;
+		/* XXX For now we're using only 48 bits sequence numbers */
+		const u32 dccp_header_size = sizeof(*dh) +
+					     sizeof(struct dccp_hdr_ext) +
+					  dccp_packet_hdr_len(dcb->dccpd_type);
+		int err, set_ack = 1;
+		u64 ackno = dp->dccps_gsr;
+		/*
+		 * Increment GSS here already in case the option code needs it.
+		 * Update GSS for real only if option processing below succeeds.
+		 */
+		dcb->dccpd_seq = ADD48(dp->dccps_gss, 1);
+
+		switch (dcb->dccpd_type) {
+		case DCCP_PKT_DATA:
+			set_ack = 0;
+			/* fall through */
+		case DCCP_PKT_DATAACK:
+		case DCCP_PKT_RESET:
+			break;
+
+		case DCCP_PKT_REQUEST:
+			set_ack = 0;
+			/* Use ISS on the first (non-retransmitted) Request. */
+			if (icsk->icsk_retransmits == 0)
+				dcb->dccpd_seq = dp->dccps_iss;
+			/* fall through */
+
+		case DCCP_PKT_SYNC:
+		case DCCP_PKT_SYNCACK:
+			ackno = dcb->dccpd_ack_seq;
+			/* fall through */
+		default:
+			/*
+			 * Set owner/destructor: some skbs are allocated via
+			 * alloc_skb (e.g. when retransmission may happen).
+			 * Only Data, DataAck, and Reset packets should come
+			 * through here with skb->sk set.
+			 */
+			WARN_ON(skb->sk);
+			skb_set_owner_w(skb, sk);
+			break;
+		}
+
+		if (dccp_insert_options(sk, skb)) {
+			kfree_skb(skb);
+			return -EPROTO;
+		}
+
+
+		/* Build DCCP header and checksum it. */
+		dh = dccp_zeroed_hdr(skb, dccp_header_size);
+		dh->dccph_type	= dcb->dccpd_type;
+		dh->dccph_sport	= inet->sport;
+		dh->dccph_dport	= inet->dport;
+		dh->dccph_doff	= (dccp_header_size + dcb->dccpd_opt_len) / 4;
+		dh->dccph_ccval	= dcb->dccpd_ccval;
+		dh->dccph_cscov = dp->dccps_pcslen;
+		/* XXX For now we're using only 48 bits sequence numbers */
+		dh->dccph_x	= 1;
+
+		dccp_update_gss(sk, dcb->dccpd_seq);
+		dccp_hdr_set_seq(dh, dp->dccps_gss);
+		if (set_ack)
+			dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno);
+
+		switch (dcb->dccpd_type) {
+		case DCCP_PKT_REQUEST:
+			dccp_hdr_request(skb)->dccph_req_service =
+							dp->dccps_service;
+			/*
+			 * Limit Ack window to ISS <= P.ackno <= GSS, so that
+			 * only Responses to Requests we sent are considered.
+			 */
+			dp->dccps_awl = dp->dccps_iss;
+			break;
+		case DCCP_PKT_RESET:
+			dccp_hdr_reset(skb)->dccph_reset_code =
+							dcb->dccpd_reset_code;
+			break;
+		}
+
+		icsk->icsk_af_ops->send_check(sk, 0, skb);
+
+		if (set_ack)
+			dccp_event_ack_sent(sk);
+
+		DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
+
+		err = icsk->icsk_af_ops->queue_xmit(skb, 0);
+		return net_xmit_eval(err);
+	}
+	return -ENOBUFS;
+}
+
+/**
+ * dccp_determine_ccmps  -  Find out about CCID-specfic packet-size limits
+ * We only consider the HC-sender CCID for setting the CCMPS (RFC 4340, 14.),
+ * since the RX CCID is restricted to feedback packets (Acks), which are small
+ * in comparison with the data traffic. A value of 0 means "no current CCMPS".
+ */
+static u32 dccp_determine_ccmps(const struct dccp_sock *dp)
+{
+	const struct ccid *tx_ccid = dp->dccps_hc_tx_ccid;
+
+	if (tx_ccid == NULL || tx_ccid->ccid_ops == NULL)
+		return 0;
+	return tx_ccid->ccid_ops->ccid_ccmps;
+}
+
+unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
+{
+	struct inet_connection_sock *icsk = inet_csk(sk);
+	struct dccp_sock *dp = dccp_sk(sk);
+	u32 ccmps = dccp_determine_ccmps(dp);
+	int cur_mps = ccmps ? min(pmtu, ccmps) : pmtu;
+
+	/* Account for header lengths and IPv4/v6 option overhead */
+	cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len +
+		    sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext));
+
+	/*
+	 * FIXME: this should come from the CCID infrastructure, where, say,
+	 * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
+	 * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
+	 * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
+	 * make it a multiple of 4
+	 */
+
+	cur_mps -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
+
+	/* And store cached results */
+	icsk->icsk_pmtu_cookie = pmtu;
+	dp->dccps_mss_cache = cur_mps;
+
+	return cur_mps;
+}
+
+EXPORT_SYMBOL_GPL(dccp_sync_mss);
+
+void dccp_write_space(struct sock *sk)
+{
+	read_lock(&sk->sk_callback_lock);
+
+	if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
+		wake_up_interruptible(sk->sk_sleep);
+	/* Should agree with poll, otherwise some programs break */
+	if (sock_writeable(sk))
+		sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
+
+	read_unlock(&sk->sk_callback_lock);
+}
+
+/**
+ * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
+ * @sk:    socket to wait for
+ * @skb:   current skb to pass on for waiting
+ * @delay: sleep timeout in milliseconds (> 0)
+ * This function is called by default when the socket is closed, and
+ * when a non-zero linger time is set on the socket. For consistency
+ */
+static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	DEFINE_WAIT(wait);
+	unsigned long jiffdelay;
+	int rc;
+
+	do {
+		dccp_pr_debug("delayed send by %d msec\n", delay);
+		jiffdelay = msecs_to_jiffies(delay);
+
+		prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
+
+		sk->sk_write_pending++;
+		release_sock(sk);
+		schedule_timeout(jiffdelay);
+		lock_sock(sk);
+		sk->sk_write_pending--;
+
+		if (sk->sk_err)
+			goto do_error;
+		if (signal_pending(current))
+			goto do_interrupted;
+
+		rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
+	} while ((delay = rc) > 0);
+out:
+	finish_wait(sk->sk_sleep, &wait);
+	return rc;
+
+do_error:
+	rc = -EPIPE;
+	goto out;
+do_interrupted:
+	rc = -EINTR;
+	goto out;
+}
+
+void dccp_write_xmit(struct sock *sk, int block)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct sk_buff *skb;
+
+	while ((skb = skb_peek(&sk->sk_write_queue))) {
+		int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
+
+		if (err > 0) {
+			if (!block) {
+				sk_reset_timer(sk, &dp->dccps_xmit_timer,
+						msecs_to_jiffies(err)+jiffies);
+				break;
+			} else
+				err = dccp_wait_for_ccid(sk, skb, err);
+			if (err && err != -EINTR)
+				DCCP_BUG("err=%d after dccp_wait_for_ccid", err);
+		}
+
+		skb_dequeue(&sk->sk_write_queue);
+		if (err == 0) {
+			struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
+			const int len = skb->len;
+
+			if (sk->sk_state == DCCP_PARTOPEN) {
+				/* See 8.1.5.  Handshake Completion */
+				inet_csk_schedule_ack(sk);
+				inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
+						  inet_csk(sk)->icsk_rto,
+						  DCCP_RTO_MAX);
+				dcb->dccpd_type = DCCP_PKT_DATAACK;
+			} else if (dccp_ack_pending(sk))
+				dcb->dccpd_type = DCCP_PKT_DATAACK;
+			else
+				dcb->dccpd_type = DCCP_PKT_DATA;
+
+			err = dccp_transmit_skb(sk, skb);
+			ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
+			if (err)
+				DCCP_BUG("err=%d after ccid_hc_tx_packet_sent",
+					 err);
+		} else {
+			dccp_pr_debug("packet discarded due to err=%d\n", err);
+			kfree_skb(skb);
+		}
+	}
+}
+
+/**
+ * dccp_retransmit_skb  -  Retransmit Request, Close, or CloseReq packets
+ * There are only four retransmittable packet types in DCCP:
+ * - Request  in client-REQUEST  state (sec. 8.1.1),
+ * - CloseReq in server-CLOSEREQ state (sec. 8.3),
+ * - Close    in   node-CLOSING  state (sec. 8.3),
+ * - Acks in client-PARTOPEN state (sec. 8.1.5, handled by dccp_delack_timer()).
+ * This function expects sk->sk_send_head to contain the original skb.
+ */
+int dccp_retransmit_skb(struct sock *sk)
+{
+	WARN_ON(sk->sk_send_head == NULL);
+
+	if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0)
+		return -EHOSTUNREACH; /* Routing failure or similar. */
+
+	/* this count is used to distinguish original and retransmitted skb */
+	inet_csk(sk)->icsk_retransmits++;
+
+	return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC));
+}
+
+struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
+				   struct request_sock *req)
+{
+	struct dccp_hdr *dh;
+	struct dccp_request_sock *dreq;
+	const u32 dccp_header_size = sizeof(struct dccp_hdr) +
+				     sizeof(struct dccp_hdr_ext) +
+				     sizeof(struct dccp_hdr_response);
+	struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1,
+					   GFP_ATOMIC);
+	if (skb == NULL)
+		return NULL;
+
+	/* Reserve space for headers. */
+	skb_reserve(skb, sk->sk_prot->max_header);
+
+	skb->dst = dst_clone(dst);
+
+	dreq = dccp_rsk(req);
+	if (inet_rsk(req)->acked)	/* increase ISS upon retransmission */
+		dccp_inc_seqno(&dreq->dreq_iss);
+	DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
+	DCCP_SKB_CB(skb)->dccpd_seq  = dreq->dreq_iss;
+
+	if (dccp_insert_options_rsk(dreq, skb)) {
+		kfree_skb(skb);
+		return NULL;
+	}
+
+	/* Build and checksum header */
+	dh = dccp_zeroed_hdr(skb, dccp_header_size);
+
+	dh->dccph_sport	= inet_rsk(req)->loc_port;
+	dh->dccph_dport	= inet_rsk(req)->rmt_port;
+	dh->dccph_doff	= (dccp_header_size +
+			   DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
+	dh->dccph_type	= DCCP_PKT_RESPONSE;
+	dh->dccph_x	= 1;
+	dccp_hdr_set_seq(dh, dreq->dreq_iss);
+	dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
+	dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
+
+	dccp_csum_outgoing(skb);
+
+	/* We use `acked' to remember that a Response was already sent. */
+	inet_rsk(req)->acked = 1;
+	DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
+	return skb;
+}
+
+EXPORT_SYMBOL_GPL(dccp_make_response);
+
+/* answer offending packet in @rcv_skb with Reset from control socket @ctl */
+struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *rcv_skb)
+{
+	struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh;
+	struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb);
+	const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
+				       sizeof(struct dccp_hdr_ext) +
+				       sizeof(struct dccp_hdr_reset);
+	struct dccp_hdr_reset *dhr;
+	struct sk_buff *skb;
+
+	skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
+	if (skb == NULL)
+		return NULL;
+
+	skb_reserve(skb, sk->sk_prot->max_header);
+
+	/* Swap the send and the receive. */
+	dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len);
+	dh->dccph_type	= DCCP_PKT_RESET;
+	dh->dccph_sport	= rxdh->dccph_dport;
+	dh->dccph_dport	= rxdh->dccph_sport;
+	dh->dccph_doff	= dccp_hdr_reset_len / 4;
+	dh->dccph_x	= 1;
+
+	dhr = dccp_hdr_reset(skb);
+	dhr->dccph_reset_code = dcb->dccpd_reset_code;
+
+	switch (dcb->dccpd_reset_code) {
+	case DCCP_RESET_CODE_PACKET_ERROR:
+		dhr->dccph_reset_data[0] = rxdh->dccph_type;
+		break;
+	case DCCP_RESET_CODE_OPTION_ERROR:	/* fall through */
+	case DCCP_RESET_CODE_MANDATORY_ERROR:
+		memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3);
+		break;
+	}
+	/*
+	 * From RFC 4340, 8.3.1:
+	 *   If P.ackno exists, set R.seqno := P.ackno + 1.
+	 *   Else set R.seqno := 0.
+	 */
+	if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
+		dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1));
+	dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq);
+
+	dccp_csum_outgoing(skb);
+	return skb;
+}
+
+EXPORT_SYMBOL_GPL(dccp_ctl_make_reset);
+
+/* send Reset on established socket, to close or abort the connection */
+int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
+{
+	struct sk_buff *skb;
+	/*
+	 * FIXME: what if rebuild_header fails?
+	 * Should we be doing a rebuild_header here?
+	 */
+	int err = inet_csk(sk)->icsk_af_ops->rebuild_header(sk);
+
+	if (err != 0)
+		return err;
+
+	skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC);
+	if (skb == NULL)
+		return -ENOBUFS;
+
+	/* Reserve space for headers and prepare control bits. */
+	skb_reserve(skb, sk->sk_prot->max_header);
+	DCCP_SKB_CB(skb)->dccpd_type	   = DCCP_PKT_RESET;
+	DCCP_SKB_CB(skb)->dccpd_reset_code = code;
+
+	return dccp_transmit_skb(sk, skb);
+}
+
+/*
+ * Do all connect socket setups that can be done AF independent.
+ */
+static inline void dccp_connect_init(struct sock *sk)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct dst_entry *dst = __sk_dst_get(sk);
+	struct inet_connection_sock *icsk = inet_csk(sk);
+
+	sk->sk_err = 0;
+	sock_reset_flag(sk, SOCK_DONE);
+
+	dccp_sync_mss(sk, dst_mtu(dst));
+
+	/* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */
+	dp->dccps_gar = dp->dccps_iss;
+
+	icsk->icsk_retransmits = 0;
+}
+
+int dccp_connect(struct sock *sk)
+{
+	struct sk_buff *skb;
+	struct inet_connection_sock *icsk = inet_csk(sk);
+
+	dccp_connect_init(sk);
+
+	skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation);
+	if (unlikely(skb == NULL))
+		return -ENOBUFS;
+
+	/* Reserve space for headers. */
+	skb_reserve(skb, sk->sk_prot->max_header);
+
+	DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
+
+	dccp_skb_entail(sk, skb);
+	dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
+	DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
+
+	/* Timer for repeating the REQUEST until an answer. */
+	inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+				  icsk->icsk_rto, DCCP_RTO_MAX);
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_connect);
+
+void dccp_send_ack(struct sock *sk)
+{
+	/* If we have been reset, we may not send again. */
+	if (sk->sk_state != DCCP_CLOSED) {
+		struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header,
+						GFP_ATOMIC);
+
+		if (skb == NULL) {
+			inet_csk_schedule_ack(sk);
+			inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN;
+			inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
+						  TCP_DELACK_MAX,
+						  DCCP_RTO_MAX);
+			return;
+		}
+
+		/* Reserve space for headers */
+		skb_reserve(skb, sk->sk_prot->max_header);
+		DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
+		dccp_transmit_skb(sk, skb);
+	}
+}
+
+EXPORT_SYMBOL_GPL(dccp_send_ack);
+
+#if 0
+/* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */
+void dccp_send_delayed_ack(struct sock *sk)
+{
+	struct inet_connection_sock *icsk = inet_csk(sk);
+	/*
+	 * FIXME: tune this timer. elapsed time fixes the skew, so no problem
+	 * with using 2s, and active senders also piggyback the ACK into a
+	 * DATAACK packet, so this is really for quiescent senders.
+	 */
+	unsigned long timeout = jiffies + 2 * HZ;
+
+	/* Use new timeout only if there wasn't a older one earlier. */
+	if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {
+		/* If delack timer was blocked or is about to expire,
+		 * send ACK now.
+		 *
+		 * FIXME: check the "about to expire" part
+		 */
+		if (icsk->icsk_ack.blocked) {
+			dccp_send_ack(sk);
+			return;
+		}
+
+		if (!time_before(timeout, icsk->icsk_ack.timeout))
+			timeout = icsk->icsk_ack.timeout;
+	}
+	icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
+	icsk->icsk_ack.timeout = timeout;
+	sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
+}
+#endif
+
+void dccp_send_sync(struct sock *sk, const u64 ackno,
+		    const enum dccp_pkt_type pkt_type)
+{
+	/*
+	 * We are not putting this on the write queue, so
+	 * dccp_transmit_skb() will set the ownership to this
+	 * sock.
+	 */
+	struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC);
+
+	if (skb == NULL) {
+		/* FIXME: how to make sure the sync is sent? */
+		DCCP_CRIT("could not send %s", dccp_packet_name(pkt_type));
+		return;
+	}
+
+	/* Reserve space for headers and prepare control bits. */
+	skb_reserve(skb, sk->sk_prot->max_header);
+	DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
+	DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno;
+
+	dccp_transmit_skb(sk, skb);
+}
+
+EXPORT_SYMBOL_GPL(dccp_send_sync);
+
+/*
+ * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This
+ * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under
+ * any circumstances.
+ */
+void dccp_send_close(struct sock *sk, const int active)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct sk_buff *skb;
+	const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC;
+
+	skb = alloc_skb(sk->sk_prot->max_header, prio);
+	if (skb == NULL)
+		return;
+
+	/* Reserve space for headers and prepare control bits. */
+	skb_reserve(skb, sk->sk_prot->max_header);
+	if (dp->dccps_role == DCCP_ROLE_SERVER && !dp->dccps_server_timewait)
+		DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSEREQ;
+	else
+		DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE;
+
+	if (active) {
+		dccp_write_xmit(sk, 1);
+		dccp_skb_entail(sk, skb);
+		dccp_transmit_skb(sk, skb_clone(skb, prio));
+		/*
+		 * Retransmission timer for active-close: RFC 4340, 8.3 requires
+		 * to retransmit the Close/CloseReq until the CLOSING/CLOSEREQ
+		 * state can be left. The initial timeout is 2 RTTs.
+		 * Since RTT measurement is done by the CCIDs, there is no easy
+		 * way to get an RTT sample. The fallback RTT from RFC 4340, 3.4
+		 * is too low (200ms); we use a high value to avoid unnecessary
+		 * retransmissions when the link RTT is > 0.2 seconds.
+		 * FIXME: Let main module sample RTTs and use that instead.
+		 */
+		inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+					  DCCP_TIMEOUT_INIT, DCCP_RTO_MAX);
+	} else
+		dccp_transmit_skb(sk, skb);
+}
diff --git a/net/dccp/probe.c b/net/dccp/probe.c
new file mode 100644
index 0000000..81368a7
--- /dev/null
+++ b/net/dccp/probe.c
@@ -0,0 +1,201 @@
+/*
+ * dccp_probe - Observe the DCCP flow with kprobes.
+ *
+ * The idea for this came from Werner Almesberger's umlsim
+ * Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
+ *
+ * Modified for DCCP from Stephen Hemminger's code
+ * Copyright (C) 2006, Ian McDonald <ian.mcdonald@jandi.co.nz>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/kprobes.h>
+#include <linux/socket.h>
+#include <linux/dccp.h>
+#include <linux/proc_fs.h>
+#include <linux/module.h>
+#include <linux/kfifo.h>
+#include <linux/vmalloc.h>
+#include <net/net_namespace.h>
+
+#include "dccp.h"
+#include "ccid.h"
+#include "ccids/ccid3.h"
+
+static int port;
+
+static int bufsize = 64 * 1024;
+
+static const char procname[] = "dccpprobe";
+
+static struct {
+	struct kfifo	  *fifo;
+	spinlock_t	  lock;
+	wait_queue_head_t wait;
+	struct timespec	  tstart;
+} dccpw;
+
+static void printl(const char *fmt, ...)
+{
+	va_list args;
+	int len;
+	struct timespec now;
+	char tbuf[256];
+
+	va_start(args, fmt);
+	getnstimeofday(&now);
+
+	now = timespec_sub(now, dccpw.tstart);
+
+	len = sprintf(tbuf, "%lu.%06lu ",
+		      (unsigned long) now.tv_sec,
+		      (unsigned long) now.tv_nsec / NSEC_PER_USEC);
+	len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args);
+	va_end(args);
+
+	kfifo_put(dccpw.fifo, tbuf, len);
+	wake_up(&dccpw.wait);
+}
+
+static int jdccp_sendmsg(struct kiocb *iocb, struct sock *sk,
+			 struct msghdr *msg, size_t size)
+{
+	const struct dccp_minisock *dmsk = dccp_msk(sk);
+	const struct inet_sock *inet = inet_sk(sk);
+	const struct ccid3_hc_tx_sock *hctx;
+
+	if (dmsk->dccpms_tx_ccid == DCCPC_CCID3)
+		hctx = ccid3_hc_tx_sk(sk);
+	else
+		hctx = NULL;
+
+	if (port == 0 || ntohs(inet->dport) == port ||
+	    ntohs(inet->sport) == port) {
+		if (hctx)
+			printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %d %d %d %u "
+			       "%llu %llu %d\n",
+			       NIPQUAD(inet->saddr), ntohs(inet->sport),
+			       NIPQUAD(inet->daddr), ntohs(inet->dport), size,
+			       hctx->ccid3hctx_s, hctx->ccid3hctx_rtt,
+			       hctx->ccid3hctx_p, hctx->ccid3hctx_x_calc,
+			       hctx->ccid3hctx_x_recv >> 6,
+			       hctx->ccid3hctx_x >> 6, hctx->ccid3hctx_t_ipi);
+		else
+			printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d\n",
+			       NIPQUAD(inet->saddr), ntohs(inet->sport),
+			       NIPQUAD(inet->daddr), ntohs(inet->dport), size);
+	}
+
+	jprobe_return();
+	return 0;
+}
+
+static struct jprobe dccp_send_probe = {
+	.kp	= {
+		.symbol_name = "dccp_sendmsg",
+	},
+	.entry	= jdccp_sendmsg,
+};
+
+static int dccpprobe_open(struct inode *inode, struct file *file)
+{
+	kfifo_reset(dccpw.fifo);
+	getnstimeofday(&dccpw.tstart);
+	return 0;
+}
+
+static ssize_t dccpprobe_read(struct file *file, char __user *buf,
+			      size_t len, loff_t *ppos)
+{
+	int error = 0, cnt = 0;
+	unsigned char *tbuf;
+
+	if (!buf)
+		return -EINVAL;
+
+	if (len == 0)
+		return 0;
+
+	tbuf = vmalloc(len);
+	if (!tbuf)
+		return -ENOMEM;
+
+	error = wait_event_interruptible(dccpw.wait,
+					 __kfifo_len(dccpw.fifo) != 0);
+	if (error)
+		goto out_free;
+
+	cnt = kfifo_get(dccpw.fifo, tbuf, len);
+	error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;
+
+out_free:
+	vfree(tbuf);
+
+	return error ? error : cnt;
+}
+
+static const struct file_operations dccpprobe_fops = {
+	.owner	 = THIS_MODULE,
+	.open	 = dccpprobe_open,
+	.read    = dccpprobe_read,
+};
+
+static __init int dccpprobe_init(void)
+{
+	int ret = -ENOMEM;
+
+	init_waitqueue_head(&dccpw.wait);
+	spin_lock_init(&dccpw.lock);
+	dccpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &dccpw.lock);
+	if (IS_ERR(dccpw.fifo))
+		return PTR_ERR(dccpw.fifo);
+
+	if (!proc_net_fops_create(&init_net, procname, S_IRUSR, &dccpprobe_fops))
+		goto err0;
+
+	ret = register_jprobe(&dccp_send_probe);
+	if (ret)
+		goto err1;
+
+	pr_info("DCCP watch registered (port=%d)\n", port);
+	return 0;
+err1:
+	proc_net_remove(&init_net, procname);
+err0:
+	kfifo_free(dccpw.fifo);
+	return ret;
+}
+module_init(dccpprobe_init);
+
+static __exit void dccpprobe_exit(void)
+{
+	kfifo_free(dccpw.fifo);
+	proc_net_remove(&init_net, procname);
+	unregister_jprobe(&dccp_send_probe);
+
+}
+module_exit(dccpprobe_exit);
+
+MODULE_PARM_DESC(port, "Port to match (0=all)");
+module_param(port, int, 0);
+
+MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
+module_param(bufsize, int, 0);
+
+MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>");
+MODULE_DESCRIPTION("DCCP snooper");
+MODULE_LICENSE("GPL");
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
new file mode 100644
index 0000000..d0bd348
--- /dev/null
+++ b/net/dccp/proto.c
@@ -0,0 +1,1169 @@
+/*
+ *  net/dccp/proto.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *	This program is free software; you can redistribute it and/or modify it
+ *	under the terms of the GNU General Public License version 2 as
+ *	published by the Free Software Foundation.
+ */
+
+#include <linux/dccp.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/in.h>
+#include <linux/if_arp.h>
+#include <linux/init.h>
+#include <linux/random.h>
+#include <net/checksum.h>
+
+#include <net/inet_sock.h>
+#include <net/sock.h>
+#include <net/xfrm.h>
+
+#include <asm/ioctls.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/delay.h>
+#include <linux/poll.h>
+
+#include "ccid.h"
+#include "dccp.h"
+#include "feat.h"
+
+DEFINE_SNMP_STAT(struct dccp_mib, dccp_statistics) __read_mostly;
+
+EXPORT_SYMBOL_GPL(dccp_statistics);
+
+atomic_t dccp_orphan_count = ATOMIC_INIT(0);
+
+EXPORT_SYMBOL_GPL(dccp_orphan_count);
+
+struct inet_hashinfo __cacheline_aligned dccp_hashinfo = {
+	.lhash_lock	= RW_LOCK_UNLOCKED,
+	.lhash_users	= ATOMIC_INIT(0),
+	.lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(dccp_hashinfo.lhash_wait),
+};
+
+EXPORT_SYMBOL_GPL(dccp_hashinfo);
+
+/* the maximum queue length for tx in packets. 0 is no limit */
+int sysctl_dccp_tx_qlen __read_mostly = 5;
+
+void dccp_set_state(struct sock *sk, const int state)
+{
+	const int oldstate = sk->sk_state;
+
+	dccp_pr_debug("%s(%p)  %s  -->  %s\n", dccp_role(sk), sk,
+		      dccp_state_name(oldstate), dccp_state_name(state));
+	WARN_ON(state == oldstate);
+
+	switch (state) {
+	case DCCP_OPEN:
+		if (oldstate != DCCP_OPEN)
+			DCCP_INC_STATS(DCCP_MIB_CURRESTAB);
+		break;
+
+	case DCCP_CLOSED:
+		if (oldstate == DCCP_OPEN || oldstate == DCCP_ACTIVE_CLOSEREQ ||
+		    oldstate == DCCP_CLOSING)
+			DCCP_INC_STATS(DCCP_MIB_ESTABRESETS);
+
+		sk->sk_prot->unhash(sk);
+		if (inet_csk(sk)->icsk_bind_hash != NULL &&
+		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
+			inet_put_port(sk);
+		/* fall through */
+	default:
+		if (oldstate == DCCP_OPEN)
+			DCCP_DEC_STATS(DCCP_MIB_CURRESTAB);
+	}
+
+	/* Change state AFTER socket is unhashed to avoid closed
+	 * socket sitting in hash tables.
+	 */
+	sk->sk_state = state;
+}
+
+EXPORT_SYMBOL_GPL(dccp_set_state);
+
+static void dccp_finish_passive_close(struct sock *sk)
+{
+	switch (sk->sk_state) {
+	case DCCP_PASSIVE_CLOSE:
+		/* Node (client or server) has received Close packet. */
+		dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED);
+		dccp_set_state(sk, DCCP_CLOSED);
+		break;
+	case DCCP_PASSIVE_CLOSEREQ:
+		/*
+		 * Client received CloseReq. We set the `active' flag so that
+		 * dccp_send_close() retransmits the Close as per RFC 4340, 8.3.
+		 */
+		dccp_send_close(sk, 1);
+		dccp_set_state(sk, DCCP_CLOSING);
+	}
+}
+
+void dccp_done(struct sock *sk)
+{
+	dccp_set_state(sk, DCCP_CLOSED);
+	dccp_clear_xmit_timers(sk);
+
+	sk->sk_shutdown = SHUTDOWN_MASK;
+
+	if (!sock_flag(sk, SOCK_DEAD))
+		sk->sk_state_change(sk);
+	else
+		inet_csk_destroy_sock(sk);
+}
+
+EXPORT_SYMBOL_GPL(dccp_done);
+
+const char *dccp_packet_name(const int type)
+{
+	static const char *dccp_packet_names[] = {
+		[DCCP_PKT_REQUEST]  = "REQUEST",
+		[DCCP_PKT_RESPONSE] = "RESPONSE",
+		[DCCP_PKT_DATA]	    = "DATA",
+		[DCCP_PKT_ACK]	    = "ACK",
+		[DCCP_PKT_DATAACK]  = "DATAACK",
+		[DCCP_PKT_CLOSEREQ] = "CLOSEREQ",
+		[DCCP_PKT_CLOSE]    = "CLOSE",
+		[DCCP_PKT_RESET]    = "RESET",
+		[DCCP_PKT_SYNC]	    = "SYNC",
+		[DCCP_PKT_SYNCACK]  = "SYNCACK",
+	};
+
+	if (type >= DCCP_NR_PKT_TYPES)
+		return "INVALID";
+	else
+		return dccp_packet_names[type];
+}
+
+EXPORT_SYMBOL_GPL(dccp_packet_name);
+
+const char *dccp_state_name(const int state)
+{
+	static char *dccp_state_names[] = {
+	[DCCP_OPEN]		= "OPEN",
+	[DCCP_REQUESTING]	= "REQUESTING",
+	[DCCP_PARTOPEN]		= "PARTOPEN",
+	[DCCP_LISTEN]		= "LISTEN",
+	[DCCP_RESPOND]		= "RESPOND",
+	[DCCP_CLOSING]		= "CLOSING",
+	[DCCP_ACTIVE_CLOSEREQ]	= "CLOSEREQ",
+	[DCCP_PASSIVE_CLOSE]	= "PASSIVE_CLOSE",
+	[DCCP_PASSIVE_CLOSEREQ]	= "PASSIVE_CLOSEREQ",
+	[DCCP_TIME_WAIT]	= "TIME_WAIT",
+	[DCCP_CLOSED]		= "CLOSED",
+	};
+
+	if (state >= DCCP_MAX_STATES)
+		return "INVALID STATE!";
+	else
+		return dccp_state_names[state];
+}
+
+EXPORT_SYMBOL_GPL(dccp_state_name);
+
+int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct dccp_minisock *dmsk = dccp_msk(sk);
+	struct inet_connection_sock *icsk = inet_csk(sk);
+
+	dccp_minisock_init(&dp->dccps_minisock);
+
+	icsk->icsk_rto		= DCCP_TIMEOUT_INIT;
+	icsk->icsk_syn_retries	= sysctl_dccp_request_retries;
+	sk->sk_state		= DCCP_CLOSED;
+	sk->sk_write_space	= dccp_write_space;
+	icsk->icsk_sync_mss	= dccp_sync_mss;
+	dp->dccps_mss_cache	= 536;
+	dp->dccps_rate_last	= jiffies;
+	dp->dccps_role		= DCCP_ROLE_UNDEFINED;
+	dp->dccps_service	= DCCP_SERVICE_CODE_IS_ABSENT;
+	dp->dccps_l_ack_ratio	= dp->dccps_r_ack_ratio = 1;
+
+	dccp_init_xmit_timers(sk);
+
+	/*
+	 * FIXME: We're hardcoding the CCID, and doing this at this point makes
+	 * the listening (master) sock get CCID control blocks, which is not
+	 * necessary, but for now, to not mess with the test userspace apps,
+	 * lets leave it here, later the real solution is to do this in a
+	 * setsockopt(CCIDs-I-want/accept). -acme
+	 */
+	if (likely(ctl_sock_initialized)) {
+		int rc = dccp_feat_init(dmsk);
+
+		if (rc)
+			return rc;
+
+		if (dmsk->dccpms_send_ack_vector) {
+			dp->dccps_hc_rx_ackvec = dccp_ackvec_alloc(GFP_KERNEL);
+			if (dp->dccps_hc_rx_ackvec == NULL)
+				return -ENOMEM;
+		}
+		dp->dccps_hc_rx_ccid = ccid_hc_rx_new(dmsk->dccpms_rx_ccid,
+						      sk, GFP_KERNEL);
+		dp->dccps_hc_tx_ccid = ccid_hc_tx_new(dmsk->dccpms_tx_ccid,
+						      sk, GFP_KERNEL);
+		if (unlikely(dp->dccps_hc_rx_ccid == NULL ||
+			     dp->dccps_hc_tx_ccid == NULL)) {
+			ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
+			ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
+			if (dmsk->dccpms_send_ack_vector) {
+				dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
+				dp->dccps_hc_rx_ackvec = NULL;
+			}
+			dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
+			return -ENOMEM;
+		}
+	} else {
+		/* control socket doesn't need feat nego */
+		INIT_LIST_HEAD(&dmsk->dccpms_pending);
+		INIT_LIST_HEAD(&dmsk->dccpms_conf);
+	}
+
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(dccp_init_sock);
+
+void dccp_destroy_sock(struct sock *sk)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct dccp_minisock *dmsk = dccp_msk(sk);
+
+	/*
+	 * DCCP doesn't use sk_write_queue, just sk_send_head
+	 * for retransmissions
+	 */
+	if (sk->sk_send_head != NULL) {
+		kfree_skb(sk->sk_send_head);
+		sk->sk_send_head = NULL;
+	}
+
+	/* Clean up a referenced DCCP bind bucket. */
+	if (inet_csk(sk)->icsk_bind_hash != NULL)
+		inet_put_port(sk);
+
+	kfree(dp->dccps_service_list);
+	dp->dccps_service_list = NULL;
+
+	if (dmsk->dccpms_send_ack_vector) {
+		dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
+		dp->dccps_hc_rx_ackvec = NULL;
+	}
+	ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
+	ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
+	dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
+
+	/* clean up feature negotiation state */
+	dccp_feat_clean(dmsk);
+}
+
+EXPORT_SYMBOL_GPL(dccp_destroy_sock);
+
+static inline int dccp_listen_start(struct sock *sk, int backlog)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+
+	dp->dccps_role = DCCP_ROLE_LISTEN;
+	return inet_csk_listen_start(sk, backlog);
+}
+
+static inline int dccp_need_reset(int state)
+{
+	return state != DCCP_CLOSED && state != DCCP_LISTEN &&
+	       state != DCCP_REQUESTING;
+}
+
+int dccp_disconnect(struct sock *sk, int flags)
+{
+	struct inet_connection_sock *icsk = inet_csk(sk);
+	struct inet_sock *inet = inet_sk(sk);
+	int err = 0;
+	const int old_state = sk->sk_state;
+
+	if (old_state != DCCP_CLOSED)
+		dccp_set_state(sk, DCCP_CLOSED);
+
+	/*
+	 * This corresponds to the ABORT function of RFC793, sec. 3.8
+	 * TCP uses a RST segment, DCCP a Reset packet with Code 2, "Aborted".
+	 */
+	if (old_state == DCCP_LISTEN) {
+		inet_csk_listen_stop(sk);
+	} else if (dccp_need_reset(old_state)) {
+		dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
+		sk->sk_err = ECONNRESET;
+	} else if (old_state == DCCP_REQUESTING)
+		sk->sk_err = ECONNRESET;
+
+	dccp_clear_xmit_timers(sk);
+
+	__skb_queue_purge(&sk->sk_receive_queue);
+	__skb_queue_purge(&sk->sk_write_queue);
+	if (sk->sk_send_head != NULL) {
+		__kfree_skb(sk->sk_send_head);
+		sk->sk_send_head = NULL;
+	}
+
+	inet->dport = 0;
+
+	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
+		inet_reset_saddr(sk);
+
+	sk->sk_shutdown = 0;
+	sock_reset_flag(sk, SOCK_DONE);
+
+	icsk->icsk_backoff = 0;
+	inet_csk_delack_init(sk);
+	__sk_dst_reset(sk);
+
+	WARN_ON(inet->num && !icsk->icsk_bind_hash);
+
+	sk->sk_error_report(sk);
+	return err;
+}
+
+EXPORT_SYMBOL_GPL(dccp_disconnect);
+
+/*
+ *	Wait for a DCCP event.
+ *
+ *	Note that we don't need to lock the socket, as the upper poll layers
+ *	take care of normal races (between the test and the event) and we don't
+ *	go look at any of the socket buffers directly.
+ */
+unsigned int dccp_poll(struct file *file, struct socket *sock,
+		       poll_table *wait)
+{
+	unsigned int mask;
+	struct sock *sk = sock->sk;
+
+	poll_wait(file, sk->sk_sleep, wait);
+	if (sk->sk_state == DCCP_LISTEN)
+		return inet_csk_listen_poll(sk);
+
+	/* Socket is not locked. We are protected from async events
+	   by poll logic and correct handling of state changes
+	   made by another threads is impossible in any case.
+	 */
+
+	mask = 0;
+	if (sk->sk_err)
+		mask = POLLERR;
+
+	if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == DCCP_CLOSED)
+		mask |= POLLHUP;
+	if (sk->sk_shutdown & RCV_SHUTDOWN)
+		mask |= POLLIN | POLLRDNORM | POLLRDHUP;
+
+	/* Connected? */
+	if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_RESPOND)) {
+		if (atomic_read(&sk->sk_rmem_alloc) > 0)
+			mask |= POLLIN | POLLRDNORM;
+
+		if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
+			if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
+				mask |= POLLOUT | POLLWRNORM;
+			} else {  /* send SIGIO later */
+				set_bit(SOCK_ASYNC_NOSPACE,
+					&sk->sk_socket->flags);
+				set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+
+				/* Race breaker. If space is freed after
+				 * wspace test but before the flags are set,
+				 * IO signal will be lost.
+				 */
+				if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
+					mask |= POLLOUT | POLLWRNORM;
+			}
+		}
+	}
+	return mask;
+}
+
+EXPORT_SYMBOL_GPL(dccp_poll);
+
+int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
+{
+	int rc = -ENOTCONN;
+
+	lock_sock(sk);
+
+	if (sk->sk_state == DCCP_LISTEN)
+		goto out;
+
+	switch (cmd) {
+	case SIOCINQ: {
+		struct sk_buff *skb;
+		unsigned long amount = 0;
+
+		skb = skb_peek(&sk->sk_receive_queue);
+		if (skb != NULL) {
+			/*
+			 * We will only return the amount of this packet since
+			 * that is all that will be read.
+			 */
+			amount = skb->len;
+		}
+		rc = put_user(amount, (int __user *)arg);
+	}
+		break;
+	default:
+		rc = -ENOIOCTLCMD;
+		break;
+	}
+out:
+	release_sock(sk);
+	return rc;
+}
+
+EXPORT_SYMBOL_GPL(dccp_ioctl);
+
+static int dccp_setsockopt_service(struct sock *sk, const __be32 service,
+				   char __user *optval, int optlen)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct dccp_service_list *sl = NULL;
+
+	if (service == DCCP_SERVICE_INVALID_VALUE ||
+	    optlen > DCCP_SERVICE_LIST_MAX_LEN * sizeof(u32))
+		return -EINVAL;
+
+	if (optlen > sizeof(service)) {
+		sl = kmalloc(optlen, GFP_KERNEL);
+		if (sl == NULL)
+			return -ENOMEM;
+
+		sl->dccpsl_nr = optlen / sizeof(u32) - 1;
+		if (copy_from_user(sl->dccpsl_list,
+				   optval + sizeof(service),
+				   optlen - sizeof(service)) ||
+		    dccp_list_has_service(sl, DCCP_SERVICE_INVALID_VALUE)) {
+			kfree(sl);
+			return -EFAULT;
+		}
+	}
+
+	lock_sock(sk);
+	dp->dccps_service = service;
+
+	kfree(dp->dccps_service_list);
+
+	dp->dccps_service_list = sl;
+	release_sock(sk);
+	return 0;
+}
+
+/* byte 1 is feature.  the rest is the preference list */
+static int dccp_setsockopt_change(struct sock *sk, int type,
+				  struct dccp_so_feat __user *optval)
+{
+	struct dccp_so_feat opt;
+	u8 *val;
+	int rc;
+
+	if (copy_from_user(&opt, optval, sizeof(opt)))
+		return -EFAULT;
+	/*
+	 * rfc4340: 6.1. Change Options
+	 */
+	if (opt.dccpsf_len < 1)
+		return -EINVAL;
+
+	val = kmalloc(opt.dccpsf_len, GFP_KERNEL);
+	if (!val)
+		return -ENOMEM;
+
+	if (copy_from_user(val, opt.dccpsf_val, opt.dccpsf_len)) {
+		rc = -EFAULT;
+		goto out_free_val;
+	}
+
+	rc = dccp_feat_change(dccp_msk(sk), type, opt.dccpsf_feat,
+			      val, opt.dccpsf_len, GFP_KERNEL);
+	if (rc)
+		goto out_free_val;
+
+out:
+	return rc;
+
+out_free_val:
+	kfree(val);
+	goto out;
+}
+
+static int do_dccp_setsockopt(struct sock *sk, int level, int optname,
+		char __user *optval, int optlen)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	int val, err = 0;
+
+	if (optlen < sizeof(int))
+		return -EINVAL;
+
+	if (get_user(val, (int __user *)optval))
+		return -EFAULT;
+
+	if (optname == DCCP_SOCKOPT_SERVICE)
+		return dccp_setsockopt_service(sk, val, optval, optlen);
+
+	lock_sock(sk);
+	switch (optname) {
+	case DCCP_SOCKOPT_PACKET_SIZE:
+		DCCP_WARN("sockopt(PACKET_SIZE) is deprecated: fix your app\n");
+		err = 0;
+		break;
+	case DCCP_SOCKOPT_CHANGE_L:
+		if (optlen != sizeof(struct dccp_so_feat))
+			err = -EINVAL;
+		else
+			err = dccp_setsockopt_change(sk, DCCPO_CHANGE_L,
+						     (struct dccp_so_feat __user *)
+						     optval);
+		break;
+	case DCCP_SOCKOPT_CHANGE_R:
+		if (optlen != sizeof(struct dccp_so_feat))
+			err = -EINVAL;
+		else
+			err = dccp_setsockopt_change(sk, DCCPO_CHANGE_R,
+						     (struct dccp_so_feat __user *)
+						     optval);
+		break;
+	case DCCP_SOCKOPT_SERVER_TIMEWAIT:
+		if (dp->dccps_role != DCCP_ROLE_SERVER)
+			err = -EOPNOTSUPP;
+		else
+			dp->dccps_server_timewait = (val != 0);
+		break;
+	case DCCP_SOCKOPT_SEND_CSCOV:	/* sender side, RFC 4340, sec. 9.2 */
+		if (val < 0 || val > 15)
+			err = -EINVAL;
+		else
+			dp->dccps_pcslen = val;
+		break;
+	case DCCP_SOCKOPT_RECV_CSCOV:	/* receiver side, RFC 4340 sec. 9.2.1 */
+		if (val < 0 || val > 15)
+			err = -EINVAL;
+		else {
+			dp->dccps_pcrlen = val;
+			/* FIXME: add feature negotiation,
+			 * ChangeL(MinimumChecksumCoverage, val) */
+		}
+		break;
+	default:
+		err = -ENOPROTOOPT;
+		break;
+	}
+
+	release_sock(sk);
+	return err;
+}
+
+int dccp_setsockopt(struct sock *sk, int level, int optname,
+		    char __user *optval, int optlen)
+{
+	if (level != SOL_DCCP)
+		return inet_csk(sk)->icsk_af_ops->setsockopt(sk, level,
+							     optname, optval,
+							     optlen);
+	return do_dccp_setsockopt(sk, level, optname, optval, optlen);
+}
+
+EXPORT_SYMBOL_GPL(dccp_setsockopt);
+
+#ifdef CONFIG_COMPAT
+int compat_dccp_setsockopt(struct sock *sk, int level, int optname,
+			   char __user *optval, int optlen)
+{
+	if (level != SOL_DCCP)
+		return inet_csk_compat_setsockopt(sk, level, optname,
+						  optval, optlen);
+	return do_dccp_setsockopt(sk, level, optname, optval, optlen);
+}
+
+EXPORT_SYMBOL_GPL(compat_dccp_setsockopt);
+#endif
+
+static int dccp_getsockopt_service(struct sock *sk, int len,
+				   __be32 __user *optval,
+				   int __user *optlen)
+{
+	const struct dccp_sock *dp = dccp_sk(sk);
+	const struct dccp_service_list *sl;
+	int err = -ENOENT, slen = 0, total_len = sizeof(u32);
+
+	lock_sock(sk);
+	if ((sl = dp->dccps_service_list) != NULL) {
+		slen = sl->dccpsl_nr * sizeof(u32);
+		total_len += slen;
+	}
+
+	err = -EINVAL;
+	if (total_len > len)
+		goto out;
+
+	err = 0;
+	if (put_user(total_len, optlen) ||
+	    put_user(dp->dccps_service, optval) ||
+	    (sl != NULL && copy_to_user(optval + 1, sl->dccpsl_list, slen)))
+		err = -EFAULT;
+out:
+	release_sock(sk);
+	return err;
+}
+
+static int do_dccp_getsockopt(struct sock *sk, int level, int optname,
+		    char __user *optval, int __user *optlen)
+{
+	struct dccp_sock *dp;
+	int val, len;
+
+	if (get_user(len, optlen))
+		return -EFAULT;
+
+	if (len < (int)sizeof(int))
+		return -EINVAL;
+
+	dp = dccp_sk(sk);
+
+	switch (optname) {
+	case DCCP_SOCKOPT_PACKET_SIZE:
+		DCCP_WARN("sockopt(PACKET_SIZE) is deprecated: fix your app\n");
+		return 0;
+	case DCCP_SOCKOPT_SERVICE:
+		return dccp_getsockopt_service(sk, len,
+					       (__be32 __user *)optval, optlen);
+	case DCCP_SOCKOPT_GET_CUR_MPS:
+		val = dp->dccps_mss_cache;
+		break;
+	case DCCP_SOCKOPT_SERVER_TIMEWAIT:
+		val = dp->dccps_server_timewait;
+		break;
+	case DCCP_SOCKOPT_SEND_CSCOV:
+		val = dp->dccps_pcslen;
+		break;
+	case DCCP_SOCKOPT_RECV_CSCOV:
+		val = dp->dccps_pcrlen;
+		break;
+	case 128 ... 191:
+		return ccid_hc_rx_getsockopt(dp->dccps_hc_rx_ccid, sk, optname,
+					     len, (u32 __user *)optval, optlen);
+	case 192 ... 255:
+		return ccid_hc_tx_getsockopt(dp->dccps_hc_tx_ccid, sk, optname,
+					     len, (u32 __user *)optval, optlen);
+	default:
+		return -ENOPROTOOPT;
+	}
+
+	len = sizeof(val);
+	if (put_user(len, optlen) || copy_to_user(optval, &val, len))
+		return -EFAULT;
+
+	return 0;
+}
+
+int dccp_getsockopt(struct sock *sk, int level, int optname,
+		    char __user *optval, int __user *optlen)
+{
+	if (level != SOL_DCCP)
+		return inet_csk(sk)->icsk_af_ops->getsockopt(sk, level,
+							     optname, optval,
+							     optlen);
+	return do_dccp_getsockopt(sk, level, optname, optval, optlen);
+}
+
+EXPORT_SYMBOL_GPL(dccp_getsockopt);
+
+#ifdef CONFIG_COMPAT
+int compat_dccp_getsockopt(struct sock *sk, int level, int optname,
+			   char __user *optval, int __user *optlen)
+{
+	if (level != SOL_DCCP)
+		return inet_csk_compat_getsockopt(sk, level, optname,
+						  optval, optlen);
+	return do_dccp_getsockopt(sk, level, optname, optval, optlen);
+}
+
+EXPORT_SYMBOL_GPL(compat_dccp_getsockopt);
+#endif
+
+int dccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
+		 size_t len)
+{
+	const struct dccp_sock *dp = dccp_sk(sk);
+	const int flags = msg->msg_flags;
+	const int noblock = flags & MSG_DONTWAIT;
+	struct sk_buff *skb;
+	int rc, size;
+	long timeo;
+
+	if (len > dp->dccps_mss_cache)
+		return -EMSGSIZE;
+
+	lock_sock(sk);
+
+	if (sysctl_dccp_tx_qlen &&
+	    (sk->sk_write_queue.qlen >= sysctl_dccp_tx_qlen)) {
+		rc = -EAGAIN;
+		goto out_release;
+	}
+
+	timeo = sock_sndtimeo(sk, noblock);
+
+	/*
+	 * We have to use sk_stream_wait_connect here to set sk_write_pending,
+	 * so that the trick in dccp_rcv_request_sent_state_process.
+	 */
+	/* Wait for a connection to finish. */
+	if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN))
+		if ((rc = sk_stream_wait_connect(sk, &timeo)) != 0)
+			goto out_release;
+
+	size = sk->sk_prot->max_header + len;
+	release_sock(sk);
+	skb = sock_alloc_send_skb(sk, size, noblock, &rc);
+	lock_sock(sk);
+	if (skb == NULL)
+		goto out_release;
+
+	skb_reserve(skb, sk->sk_prot->max_header);
+	rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
+	if (rc != 0)
+		goto out_discard;
+
+	skb_queue_tail(&sk->sk_write_queue, skb);
+	dccp_write_xmit(sk,0);
+out_release:
+	release_sock(sk);
+	return rc ? : len;
+out_discard:
+	kfree_skb(skb);
+	goto out_release;
+}
+
+EXPORT_SYMBOL_GPL(dccp_sendmsg);
+
+int dccp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
+		 size_t len, int nonblock, int flags, int *addr_len)
+{
+	const struct dccp_hdr *dh;
+	long timeo;
+
+	lock_sock(sk);
+
+	if (sk->sk_state == DCCP_LISTEN) {
+		len = -ENOTCONN;
+		goto out;
+	}
+
+	timeo = sock_rcvtimeo(sk, nonblock);
+
+	do {
+		struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
+
+		if (skb == NULL)
+			goto verify_sock_status;
+
+		dh = dccp_hdr(skb);
+
+		switch (dh->dccph_type) {
+		case DCCP_PKT_DATA:
+		case DCCP_PKT_DATAACK:
+			goto found_ok_skb;
+
+		case DCCP_PKT_CLOSE:
+		case DCCP_PKT_CLOSEREQ:
+			if (!(flags & MSG_PEEK))
+				dccp_finish_passive_close(sk);
+			/* fall through */
+		case DCCP_PKT_RESET:
+			dccp_pr_debug("found fin (%s) ok!\n",
+				      dccp_packet_name(dh->dccph_type));
+			len = 0;
+			goto found_fin_ok;
+		default:
+			dccp_pr_debug("packet_type=%s\n",
+				      dccp_packet_name(dh->dccph_type));
+			sk_eat_skb(sk, skb, 0);
+		}
+verify_sock_status:
+		if (sock_flag(sk, SOCK_DONE)) {
+			len = 0;
+			break;
+		}
+
+		if (sk->sk_err) {
+			len = sock_error(sk);
+			break;
+		}
+
+		if (sk->sk_shutdown & RCV_SHUTDOWN) {
+			len = 0;
+			break;
+		}
+
+		if (sk->sk_state == DCCP_CLOSED) {
+			if (!sock_flag(sk, SOCK_DONE)) {
+				/* This occurs when user tries to read
+				 * from never connected socket.
+				 */
+				len = -ENOTCONN;
+				break;
+			}
+			len = 0;
+			break;
+		}
+
+		if (!timeo) {
+			len = -EAGAIN;
+			break;
+		}
+
+		if (signal_pending(current)) {
+			len = sock_intr_errno(timeo);
+			break;
+		}
+
+		sk_wait_data(sk, &timeo);
+		continue;
+	found_ok_skb:
+		if (len > skb->len)
+			len = skb->len;
+		else if (len < skb->len)
+			msg->msg_flags |= MSG_TRUNC;
+
+		if (skb_copy_datagram_iovec(skb, 0, msg->msg_iov, len)) {
+			/* Exception. Bailout! */
+			len = -EFAULT;
+			break;
+		}
+	found_fin_ok:
+		if (!(flags & MSG_PEEK))
+			sk_eat_skb(sk, skb, 0);
+		break;
+	} while (1);
+out:
+	release_sock(sk);
+	return len;
+}
+
+EXPORT_SYMBOL_GPL(dccp_recvmsg);
+
+int inet_dccp_listen(struct socket *sock, int backlog)
+{
+	struct sock *sk = sock->sk;
+	unsigned char old_state;
+	int err;
+
+	lock_sock(sk);
+
+	err = -EINVAL;
+	if (sock->state != SS_UNCONNECTED || sock->type != SOCK_DCCP)
+		goto out;
+
+	old_state = sk->sk_state;
+	if (!((1 << old_state) & (DCCPF_CLOSED | DCCPF_LISTEN)))
+		goto out;
+
+	/* Really, if the socket is already in listen state
+	 * we can only allow the backlog to be adjusted.
+	 */
+	if (old_state != DCCP_LISTEN) {
+		/*
+		 * FIXME: here it probably should be sk->sk_prot->listen_start
+		 * see tcp_listen_start
+		 */
+		err = dccp_listen_start(sk, backlog);
+		if (err)
+			goto out;
+	}
+	sk->sk_max_ack_backlog = backlog;
+	err = 0;
+
+out:
+	release_sock(sk);
+	return err;
+}
+
+EXPORT_SYMBOL_GPL(inet_dccp_listen);
+
+static void dccp_terminate_connection(struct sock *sk)
+{
+	u8 next_state = DCCP_CLOSED;
+
+	switch (sk->sk_state) {
+	case DCCP_PASSIVE_CLOSE:
+	case DCCP_PASSIVE_CLOSEREQ:
+		dccp_finish_passive_close(sk);
+		break;
+	case DCCP_PARTOPEN:
+		dccp_pr_debug("Stop PARTOPEN timer (%p)\n", sk);
+		inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
+		/* fall through */
+	case DCCP_OPEN:
+		dccp_send_close(sk, 1);
+
+		if (dccp_sk(sk)->dccps_role == DCCP_ROLE_SERVER &&
+		    !dccp_sk(sk)->dccps_server_timewait)
+			next_state = DCCP_ACTIVE_CLOSEREQ;
+		else
+			next_state = DCCP_CLOSING;
+		/* fall through */
+	default:
+		dccp_set_state(sk, next_state);
+	}
+}
+
+void dccp_close(struct sock *sk, long timeout)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct sk_buff *skb;
+	u32 data_was_unread = 0;
+	int state;
+
+	lock_sock(sk);
+
+	sk->sk_shutdown = SHUTDOWN_MASK;
+
+	if (sk->sk_state == DCCP_LISTEN) {
+		dccp_set_state(sk, DCCP_CLOSED);
+
+		/* Special case. */
+		inet_csk_listen_stop(sk);
+
+		goto adjudge_to_death;
+	}
+
+	sk_stop_timer(sk, &dp->dccps_xmit_timer);
+
+	/*
+	 * We need to flush the recv. buffs.  We do this only on the
+	 * descriptor close, not protocol-sourced closes, because the
+	  *reader process may not have drained the data yet!
+	 */
+	while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
+		data_was_unread += skb->len;
+		__kfree_skb(skb);
+	}
+
+	if (data_was_unread) {
+		/* Unread data was tossed, send an appropriate Reset Code */
+		DCCP_WARN("DCCP: ABORT -- %u bytes unread\n", data_was_unread);
+		dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
+		dccp_set_state(sk, DCCP_CLOSED);
+	} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
+		/* Check zero linger _after_ checking for unread data. */
+		sk->sk_prot->disconnect(sk, 0);
+	} else if (sk->sk_state != DCCP_CLOSED) {
+		dccp_terminate_connection(sk);
+	}
+
+	sk_stream_wait_close(sk, timeout);
+
+adjudge_to_death:
+	state = sk->sk_state;
+	sock_hold(sk);
+	sock_orphan(sk);
+	atomic_inc(sk->sk_prot->orphan_count);
+
+	/*
+	 * It is the last release_sock in its life. It will remove backlog.
+	 */
+	release_sock(sk);
+	/*
+	 * Now socket is owned by kernel and we acquire BH lock
+	 * to finish close. No need to check for user refs.
+	 */
+	local_bh_disable();
+	bh_lock_sock(sk);
+	WARN_ON(sock_owned_by_user(sk));
+
+	/* Have we already been destroyed by a softirq or backlog? */
+	if (state != DCCP_CLOSED && sk->sk_state == DCCP_CLOSED)
+		goto out;
+
+	if (sk->sk_state == DCCP_CLOSED)
+		inet_csk_destroy_sock(sk);
+
+	/* Otherwise, socket is reprieved until protocol close. */
+
+out:
+	bh_unlock_sock(sk);
+	local_bh_enable();
+	sock_put(sk);
+}
+
+EXPORT_SYMBOL_GPL(dccp_close);
+
+void dccp_shutdown(struct sock *sk, int how)
+{
+	dccp_pr_debug("called shutdown(%x)\n", how);
+}
+
+EXPORT_SYMBOL_GPL(dccp_shutdown);
+
+static inline int dccp_mib_init(void)
+{
+	return snmp_mib_init((void**)dccp_statistics, sizeof(struct dccp_mib));
+}
+
+static inline void dccp_mib_exit(void)
+{
+	snmp_mib_free((void**)dccp_statistics);
+}
+
+static int thash_entries;
+module_param(thash_entries, int, 0444);
+MODULE_PARM_DESC(thash_entries, "Number of ehash buckets");
+
+#ifdef CONFIG_IP_DCCP_DEBUG
+int dccp_debug;
+module_param(dccp_debug, bool, 0644);
+MODULE_PARM_DESC(dccp_debug, "Enable debug messages");
+
+EXPORT_SYMBOL_GPL(dccp_debug);
+#endif
+
+static int __init dccp_init(void)
+{
+	unsigned long goal;
+	int ehash_order, bhash_order, i;
+	int rc = -ENOBUFS;
+
+	BUILD_BUG_ON(sizeof(struct dccp_skb_cb) >
+		     FIELD_SIZEOF(struct sk_buff, cb));
+
+	dccp_hashinfo.bind_bucket_cachep =
+		kmem_cache_create("dccp_bind_bucket",
+				  sizeof(struct inet_bind_bucket), 0,
+				  SLAB_HWCACHE_ALIGN, NULL);
+	if (!dccp_hashinfo.bind_bucket_cachep)
+		goto out;
+
+	/*
+	 * Size and allocate the main established and bind bucket
+	 * hash tables.
+	 *
+	 * The methodology is similar to that of the buffer cache.
+	 */
+	if (num_physpages >= (128 * 1024))
+		goal = num_physpages >> (21 - PAGE_SHIFT);
+	else
+		goal = num_physpages >> (23 - PAGE_SHIFT);
+
+	if (thash_entries)
+		goal = (thash_entries *
+			sizeof(struct inet_ehash_bucket)) >> PAGE_SHIFT;
+	for (ehash_order = 0; (1UL << ehash_order) < goal; ehash_order++)
+		;
+	do {
+		dccp_hashinfo.ehash_size = (1UL << ehash_order) * PAGE_SIZE /
+					sizeof(struct inet_ehash_bucket);
+		while (dccp_hashinfo.ehash_size &
+		       (dccp_hashinfo.ehash_size - 1))
+			dccp_hashinfo.ehash_size--;
+		dccp_hashinfo.ehash = (struct inet_ehash_bucket *)
+			__get_free_pages(GFP_ATOMIC, ehash_order);
+	} while (!dccp_hashinfo.ehash && --ehash_order > 0);
+
+	if (!dccp_hashinfo.ehash) {
+		DCCP_CRIT("Failed to allocate DCCP established hash table");
+		goto out_free_bind_bucket_cachep;
+	}
+
+	for (i = 0; i < dccp_hashinfo.ehash_size; i++) {
+		INIT_HLIST_HEAD(&dccp_hashinfo.ehash[i].chain);
+		INIT_HLIST_HEAD(&dccp_hashinfo.ehash[i].twchain);
+	}
+
+	if (inet_ehash_locks_alloc(&dccp_hashinfo))
+			goto out_free_dccp_ehash;
+
+	bhash_order = ehash_order;
+
+	do {
+		dccp_hashinfo.bhash_size = (1UL << bhash_order) * PAGE_SIZE /
+					sizeof(struct inet_bind_hashbucket);
+		if ((dccp_hashinfo.bhash_size > (64 * 1024)) &&
+		    bhash_order > 0)
+			continue;
+		dccp_hashinfo.bhash = (struct inet_bind_hashbucket *)
+			__get_free_pages(GFP_ATOMIC, bhash_order);
+	} while (!dccp_hashinfo.bhash && --bhash_order >= 0);
+
+	if (!dccp_hashinfo.bhash) {
+		DCCP_CRIT("Failed to allocate DCCP bind hash table");
+		goto out_free_dccp_locks;
+	}
+
+	for (i = 0; i < dccp_hashinfo.bhash_size; i++) {
+		spin_lock_init(&dccp_hashinfo.bhash[i].lock);
+		INIT_HLIST_HEAD(&dccp_hashinfo.bhash[i].chain);
+	}
+
+	rc = dccp_mib_init();
+	if (rc)
+		goto out_free_dccp_bhash;
+
+	rc = dccp_ackvec_init();
+	if (rc)
+		goto out_free_dccp_mib;
+
+	rc = dccp_sysctl_init();
+	if (rc)
+		goto out_ackvec_exit;
+
+	dccp_timestamping_init();
+out:
+	return rc;
+out_ackvec_exit:
+	dccp_ackvec_exit();
+out_free_dccp_mib:
+	dccp_mib_exit();
+out_free_dccp_bhash:
+	free_pages((unsigned long)dccp_hashinfo.bhash, bhash_order);
+	dccp_hashinfo.bhash = NULL;
+out_free_dccp_locks:
+	inet_ehash_locks_free(&dccp_hashinfo);
+out_free_dccp_ehash:
+	free_pages((unsigned long)dccp_hashinfo.ehash, ehash_order);
+	dccp_hashinfo.ehash = NULL;
+out_free_bind_bucket_cachep:
+	kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep);
+	dccp_hashinfo.bind_bucket_cachep = NULL;
+	goto out;
+}
+
+static void __exit dccp_fini(void)
+{
+	dccp_mib_exit();
+	free_pages((unsigned long)dccp_hashinfo.bhash,
+		   get_order(dccp_hashinfo.bhash_size *
+			     sizeof(struct inet_bind_hashbucket)));
+	free_pages((unsigned long)dccp_hashinfo.ehash,
+		   get_order(dccp_hashinfo.ehash_size *
+			     sizeof(struct inet_ehash_bucket)));
+	inet_ehash_locks_free(&dccp_hashinfo);
+	kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep);
+	dccp_ackvec_exit();
+	dccp_sysctl_exit();
+}
+
+module_init(dccp_init);
+module_exit(dccp_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@conectiva.com.br>");
+MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");
diff --git a/net/dccp/sysctl.c b/net/dccp/sysctl.c
new file mode 100644
index 0000000..2129599
--- /dev/null
+++ b/net/dccp/sysctl.c
@@ -0,0 +1,126 @@
+/*
+ *  net/dccp/sysctl.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@mandriva.com>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License v2
+ *	as published by the Free Software Foundation.
+ */
+
+#include <linux/mm.h>
+#include <linux/sysctl.h>
+#include "dccp.h"
+#include "feat.h"
+
+#ifndef CONFIG_SYSCTL
+#error This file should not be compiled without CONFIG_SYSCTL defined
+#endif
+
+static struct ctl_table dccp_default_table[] = {
+	{
+		.procname	= "seq_window",
+		.data		= &sysctl_dccp_feat_sequence_window,
+		.maxlen		= sizeof(sysctl_dccp_feat_sequence_window),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "rx_ccid",
+		.data		= &sysctl_dccp_feat_rx_ccid,
+		.maxlen		= sizeof(sysctl_dccp_feat_rx_ccid),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "tx_ccid",
+		.data		= &sysctl_dccp_feat_tx_ccid,
+		.maxlen		= sizeof(sysctl_dccp_feat_tx_ccid),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "ack_ratio",
+		.data		= &sysctl_dccp_feat_ack_ratio,
+		.maxlen		= sizeof(sysctl_dccp_feat_ack_ratio),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "send_ackvec",
+		.data		= &sysctl_dccp_feat_send_ack_vector,
+		.maxlen		= sizeof(sysctl_dccp_feat_send_ack_vector),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "send_ndp",
+		.data		= &sysctl_dccp_feat_send_ndp_count,
+		.maxlen		= sizeof(sysctl_dccp_feat_send_ndp_count),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "request_retries",
+		.data		= &sysctl_dccp_request_retries,
+		.maxlen		= sizeof(sysctl_dccp_request_retries),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "retries1",
+		.data		= &sysctl_dccp_retries1,
+		.maxlen		= sizeof(sysctl_dccp_retries1),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "retries2",
+		.data		= &sysctl_dccp_retries2,
+		.maxlen		= sizeof(sysctl_dccp_retries2),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "tx_qlen",
+		.data		= &sysctl_dccp_tx_qlen,
+		.maxlen		= sizeof(sysctl_dccp_tx_qlen),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "sync_ratelimit",
+		.data		= &sysctl_dccp_sync_ratelimit,
+		.maxlen		= sizeof(sysctl_dccp_sync_ratelimit),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_ms_jiffies,
+	},
+
+	{ .ctl_name = 0, }
+};
+
+static struct ctl_path dccp_path[] = {
+	{ .procname = "net", .ctl_name = CTL_NET, },
+	{ .procname = "dccp", .ctl_name = NET_DCCP, },
+	{ .procname = "default", .ctl_name = NET_DCCP_DEFAULT, },
+	{ }
+};
+
+static struct ctl_table_header *dccp_table_header;
+
+int __init dccp_sysctl_init(void)
+{
+	dccp_table_header = register_sysctl_paths(dccp_path,
+			dccp_default_table);
+
+	return dccp_table_header != NULL ? 0 : -ENOMEM;
+}
+
+void dccp_sysctl_exit(void)
+{
+	if (dccp_table_header != NULL) {
+		unregister_sysctl_table(dccp_table_header);
+		dccp_table_header = NULL;
+	}
+}
diff --git a/net/dccp/timer.c b/net/dccp/timer.c
new file mode 100644
index 0000000..54b3c7e
--- /dev/null
+++ b/net/dccp/timer.c
@@ -0,0 +1,301 @@
+/*
+ *  net/dccp/timer.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/dccp.h>
+#include <linux/skbuff.h>
+
+#include "dccp.h"
+
+/* sysctl variables governing numbers of retransmission attempts */
+int  sysctl_dccp_request_retries	__read_mostly = TCP_SYN_RETRIES;
+int  sysctl_dccp_retries1		__read_mostly = TCP_RETR1;
+int  sysctl_dccp_retries2		__read_mostly = TCP_RETR2;
+
+static void dccp_write_err(struct sock *sk)
+{
+	sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
+	sk->sk_error_report(sk);
+
+	dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
+	dccp_done(sk);
+	DCCP_INC_STATS_BH(DCCP_MIB_ABORTONTIMEOUT);
+}
+
+/* A write timeout has occurred. Process the after effects. */
+static int dccp_write_timeout(struct sock *sk)
+{
+	const struct inet_connection_sock *icsk = inet_csk(sk);
+	int retry_until;
+
+	if (sk->sk_state == DCCP_REQUESTING || sk->sk_state == DCCP_PARTOPEN) {
+		if (icsk->icsk_retransmits != 0)
+			dst_negative_advice(&sk->sk_dst_cache);
+		retry_until = icsk->icsk_syn_retries ?
+			    : sysctl_dccp_request_retries;
+	} else {
+		if (icsk->icsk_retransmits >= sysctl_dccp_retries1) {
+			/* NOTE. draft-ietf-tcpimpl-pmtud-01.txt requires pmtu
+			   black hole detection. :-(
+
+			   It is place to make it. It is not made. I do not want
+			   to make it. It is disguisting. It does not work in any
+			   case. Let me to cite the same draft, which requires for
+			   us to implement this:
+
+   "The one security concern raised by this memo is that ICMP black holes
+   are often caused by over-zealous security administrators who block
+   all ICMP messages.  It is vitally important that those who design and
+   deploy security systems understand the impact of strict filtering on
+   upper-layer protocols.  The safest web site in the world is worthless
+   if most TCP implementations cannot transfer data from it.  It would
+   be far nicer to have all of the black holes fixed rather than fixing
+   all of the TCP implementations."
+
+			   Golden words :-).
+		   */
+
+			dst_negative_advice(&sk->sk_dst_cache);
+		}
+
+		retry_until = sysctl_dccp_retries2;
+		/*
+		 * FIXME: see tcp_write_timout and tcp_out_of_resources
+		 */
+	}
+
+	if (icsk->icsk_retransmits >= retry_until) {
+		/* Has it gone just too far? */
+		dccp_write_err(sk);
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ *	The DCCP retransmit timer.
+ */
+static void dccp_retransmit_timer(struct sock *sk)
+{
+	struct inet_connection_sock *icsk = inet_csk(sk);
+
+	/* retransmit timer is used for feature negotiation throughout
+	 * connection.  In this case, no packet is re-transmitted, but rather an
+	 * ack is generated and pending changes are placed into its options.
+	 */
+	if (sk->sk_send_head == NULL) {
+		dccp_pr_debug("feat negotiation retransmit timeout %p\n", sk);
+		if (sk->sk_state == DCCP_OPEN)
+			dccp_send_ack(sk);
+		goto backoff;
+	}
+
+	/*
+	 * More than than 4MSL (8 minutes) has passed, a RESET(aborted) was
+	 * sent, no need to retransmit, this sock is dead.
+	 */
+	if (dccp_write_timeout(sk))
+		return;
+
+	/*
+	 * We want to know the number of packets retransmitted, not the
+	 * total number of retransmissions of clones of original packets.
+	 */
+	if (icsk->icsk_retransmits == 0)
+		DCCP_INC_STATS_BH(DCCP_MIB_TIMEOUTS);
+
+	if (dccp_retransmit_skb(sk) != 0) {
+		/*
+		 * Retransmission failed because of local congestion,
+		 * do not backoff.
+		 */
+		if (--icsk->icsk_retransmits == 0)
+			icsk->icsk_retransmits = 1;
+		inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
+					  min(icsk->icsk_rto,
+					      TCP_RESOURCE_PROBE_INTERVAL),
+					  DCCP_RTO_MAX);
+		return;
+	}
+
+backoff:
+	icsk->icsk_backoff++;
+
+	icsk->icsk_rto = min(icsk->icsk_rto << 1, DCCP_RTO_MAX);
+	inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto,
+				  DCCP_RTO_MAX);
+	if (icsk->icsk_retransmits > sysctl_dccp_retries1)
+		__sk_dst_reset(sk);
+}
+
+static void dccp_write_timer(unsigned long data)
+{
+	struct sock *sk = (struct sock *)data;
+	struct inet_connection_sock *icsk = inet_csk(sk);
+	int event = 0;
+
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk)) {
+		/* Try again later */
+		sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
+			       jiffies + (HZ / 20));
+		goto out;
+	}
+
+	if (sk->sk_state == DCCP_CLOSED || !icsk->icsk_pending)
+		goto out;
+
+	if (time_after(icsk->icsk_timeout, jiffies)) {
+		sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
+			       icsk->icsk_timeout);
+		goto out;
+	}
+
+	event = icsk->icsk_pending;
+	icsk->icsk_pending = 0;
+
+	switch (event) {
+	case ICSK_TIME_RETRANS:
+		dccp_retransmit_timer(sk);
+		break;
+	}
+out:
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
+
+/*
+ *	Timer for listening sockets
+ */
+static void dccp_response_timer(struct sock *sk)
+{
+	inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, DCCP_TIMEOUT_INIT,
+				   DCCP_RTO_MAX);
+}
+
+static void dccp_keepalive_timer(unsigned long data)
+{
+	struct sock *sk = (struct sock *)data;
+
+	/* Only process if socket is not in use. */
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk)) {
+		/* Try again later. */
+		inet_csk_reset_keepalive_timer(sk, HZ / 20);
+		goto out;
+	}
+
+	if (sk->sk_state == DCCP_LISTEN) {
+		dccp_response_timer(sk);
+		goto out;
+	}
+out:
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
+
+/* This is the same as tcp_delack_timer, sans prequeue & mem_reclaim stuff */
+static void dccp_delack_timer(unsigned long data)
+{
+	struct sock *sk = (struct sock *)data;
+	struct inet_connection_sock *icsk = inet_csk(sk);
+
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk)) {
+		/* Try again later. */
+		icsk->icsk_ack.blocked = 1;
+		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED);
+		sk_reset_timer(sk, &icsk->icsk_delack_timer,
+			       jiffies + TCP_DELACK_MIN);
+		goto out;
+	}
+
+	if (sk->sk_state == DCCP_CLOSED ||
+	    !(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
+		goto out;
+	if (time_after(icsk->icsk_ack.timeout, jiffies)) {
+		sk_reset_timer(sk, &icsk->icsk_delack_timer,
+			       icsk->icsk_ack.timeout);
+		goto out;
+	}
+
+	icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
+
+	if (inet_csk_ack_scheduled(sk)) {
+		if (!icsk->icsk_ack.pingpong) {
+			/* Delayed ACK missed: inflate ATO. */
+			icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1,
+						 icsk->icsk_rto);
+		} else {
+			/* Delayed ACK missed: leave pingpong mode and
+			 * deflate ATO.
+			 */
+			icsk->icsk_ack.pingpong = 0;
+			icsk->icsk_ack.ato = TCP_ATO_MIN;
+		}
+		dccp_send_ack(sk);
+		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKS);
+	}
+out:
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
+
+/* Transmit-delay timer: used by the CCIDs to delay actual send time */
+static void dccp_write_xmit_timer(unsigned long data)
+{
+	struct sock *sk = (struct sock *)data;
+	struct dccp_sock *dp = dccp_sk(sk);
+
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk))
+		sk_reset_timer(sk, &dp->dccps_xmit_timer, jiffies+1);
+	else
+		dccp_write_xmit(sk, 0);
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
+
+static void dccp_init_write_xmit_timer(struct sock *sk)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+
+	setup_timer(&dp->dccps_xmit_timer, dccp_write_xmit_timer,
+			(unsigned long)sk);
+}
+
+void dccp_init_xmit_timers(struct sock *sk)
+{
+	dccp_init_write_xmit_timer(sk);
+	inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer,
+				  &dccp_keepalive_timer);
+}
+
+static ktime_t dccp_timestamp_seed;
+/**
+ * dccp_timestamp  -  10s of microseconds time source
+ * Returns the number of 10s of microseconds since loading DCCP. This is native
+ * DCCP time difference format (RFC 4340, sec. 13).
+ * Please note: This will wrap around about circa every 11.9 hours.
+ */
+u32 dccp_timestamp(void)
+{
+	s64 delta = ktime_us_delta(ktime_get_real(), dccp_timestamp_seed);
+
+	do_div(delta, 10);
+	return delta;
+}
+EXPORT_SYMBOL_GPL(dccp_timestamp);
+
+void __init dccp_timestamping_init(void)
+{
+	dccp_timestamp_seed = ktime_get_real();
+}