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-rw-r--r--net/sctp/chunk.c309
1 files changed, 309 insertions, 0 deletions
diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
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+++ b/net/sctp/chunk.c
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+/* SCTP kernel reference Implementation
+ * (C) Copyright IBM Corp. 2003, 2004
+ *
+ * This file is part of the SCTP kernel reference Implementation
+ *
+ * This file contains the code relating the the chunk abstraction.
+ *
+ * The SCTP reference implementation 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, or (at your option)
+ * any later version.
+ *
+ * The SCTP reference implementation 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 GNU CC; see the file COPYING. If not, write to
+ * the Free Software Foundation, 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * Please send any bug reports or fixes you make to the
+ * email address(es):
+ * lksctp developers <lksctp-developers@lists.sourceforge.net>
+ *
+ * Or submit a bug report through the following website:
+ * http://www.sf.net/projects/lksctp
+ *
+ * Written or modified by:
+ * Jon Grimm <jgrimm@us.ibm.com>
+ * Sridhar Samudrala <sri@us.ibm.com>
+ *
+ * Any bugs reported given to us we will try to fix... any fixes shared will
+ * be incorporated into the next SCTP release.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/net.h>
+#include <linux/inet.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+
+/* This file is mostly in anticipation of future work, but initially
+ * populate with fragment tracking for an outbound message.
+ */
+
+/* Initialize datamsg from memory. */
+static void sctp_datamsg_init(struct sctp_datamsg *msg)
+{
+ atomic_set(&msg->refcnt, 1);
+ msg->send_failed = 0;
+ msg->send_error = 0;
+ msg->can_abandon = 0;
+ msg->expires_at = 0;
+ INIT_LIST_HEAD(&msg->chunks);
+}
+
+/* Allocate and initialize datamsg. */
+SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(int gfp)
+{
+ struct sctp_datamsg *msg;
+ msg = kmalloc(sizeof(struct sctp_datamsg), gfp);
+ if (msg)
+ sctp_datamsg_init(msg);
+ SCTP_DBG_OBJCNT_INC(datamsg);
+ return msg;
+}
+
+/* Final destructruction of datamsg memory. */
+static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
+{
+ struct list_head *pos, *temp;
+ struct sctp_chunk *chunk;
+ struct sctp_sock *sp;
+ struct sctp_ulpevent *ev;
+ struct sctp_association *asoc = NULL;
+ int error = 0, notify;
+
+ /* If we failed, we may need to notify. */
+ notify = msg->send_failed ? -1 : 0;
+
+ /* Release all references. */
+ list_for_each_safe(pos, temp, &msg->chunks) {
+ list_del_init(pos);
+ chunk = list_entry(pos, struct sctp_chunk, frag_list);
+ /* Check whether we _really_ need to notify. */
+ if (notify < 0) {
+ asoc = chunk->asoc;
+ if (msg->send_error)
+ error = msg->send_error;
+ else
+ error = asoc->outqueue.error;
+
+ sp = sctp_sk(asoc->base.sk);
+ notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED,
+ &sp->subscribe);
+ }
+
+ /* Generate a SEND FAILED event only if enabled. */
+ if (notify > 0) {
+ int sent;
+ if (chunk->has_tsn)
+ sent = SCTP_DATA_SENT;
+ else
+ sent = SCTP_DATA_UNSENT;
+
+ ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
+ error, GFP_ATOMIC);
+ if (ev)
+ sctp_ulpq_tail_event(&asoc->ulpq, ev);
+ }
+
+ sctp_chunk_put(chunk);
+ }
+
+ SCTP_DBG_OBJCNT_DEC(datamsg);
+ kfree(msg);
+}
+
+/* Hold a reference. */
+static void sctp_datamsg_hold(struct sctp_datamsg *msg)
+{
+ atomic_inc(&msg->refcnt);
+}
+
+/* Release a reference. */
+void sctp_datamsg_put(struct sctp_datamsg *msg)
+{
+ if (atomic_dec_and_test(&msg->refcnt))
+ sctp_datamsg_destroy(msg);
+}
+
+/* Free a message. Really just give up a reference, the
+ * really free happens in sctp_datamsg_destroy().
+ */
+void sctp_datamsg_free(struct sctp_datamsg *msg)
+{
+ sctp_datamsg_put(msg);
+}
+
+/* Hold on to all the fragments until all chunks have been sent. */
+void sctp_datamsg_track(struct sctp_chunk *chunk)
+{
+ sctp_chunk_hold(chunk);
+}
+
+/* Assign a chunk to this datamsg. */
+static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk)
+{
+ sctp_datamsg_hold(msg);
+ chunk->msg = msg;
+}
+
+
+/* A data chunk can have a maximum payload of (2^16 - 20). Break
+ * down any such message into smaller chunks. Opportunistically, fragment
+ * the chunks down to the current MTU constraints. We may get refragmented
+ * later if the PMTU changes, but it is _much better_ to fragment immediately
+ * with a reasonable guess than always doing our fragmentation on the
+ * soft-interrupt.
+ */
+struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
+ struct sctp_sndrcvinfo *sinfo,
+ struct msghdr *msgh, int msg_len)
+{
+ int max, whole, i, offset, over, err;
+ int len, first_len;
+ struct sctp_chunk *chunk;
+ struct sctp_datamsg *msg;
+ struct list_head *pos, *temp;
+ __u8 frag;
+
+ msg = sctp_datamsg_new(GFP_KERNEL);
+ if (!msg)
+ return NULL;
+
+ /* Note: Calculate this outside of the loop, so that all fragments
+ * have the same expiration.
+ */
+ if (sinfo->sinfo_timetolive) {
+ /* sinfo_timetolive is in milliseconds */
+ msg->expires_at = jiffies +
+ msecs_to_jiffies(sinfo->sinfo_timetolive);
+ msg->can_abandon = 1;
+ SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n",
+ __FUNCTION__, msg, msg->expires_at, jiffies);
+ }
+
+ max = asoc->frag_point;
+
+ whole = 0;
+ first_len = max;
+
+ /* Encourage Cookie-ECHO bundling. */
+ if (asoc->state < SCTP_STATE_COOKIE_ECHOED) {
+ whole = msg_len / (max - SCTP_ARBITRARY_COOKIE_ECHO_LEN);
+
+ /* Account for the DATA to be bundled with the COOKIE-ECHO. */
+ if (whole) {
+ first_len = max - SCTP_ARBITRARY_COOKIE_ECHO_LEN;
+ msg_len -= first_len;
+ whole = 1;
+ }
+ }
+
+ /* How many full sized? How many bytes leftover? */
+ whole += msg_len / max;
+ over = msg_len % max;
+ offset = 0;
+
+ if ((whole > 1) || (whole && over))
+ SCTP_INC_STATS_USER(SCTP_MIB_FRAGUSRMSGS);
+
+ /* Create chunks for all the full sized DATA chunks. */
+ for (i=0, len=first_len; i < whole; i++) {
+ frag = SCTP_DATA_MIDDLE_FRAG;
+
+ if (0 == i)
+ frag |= SCTP_DATA_FIRST_FRAG;
+
+ if ((i == (whole - 1)) && !over)
+ frag |= SCTP_DATA_LAST_FRAG;
+
+ chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);
+
+ if (!chunk)
+ goto errout;
+ err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov);
+ if (err < 0)
+ goto errout;
+
+ offset += len;
+
+ /* Put the chunk->skb back into the form expected by send. */
+ __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
+ - (__u8 *)chunk->skb->data);
+
+ sctp_datamsg_assign(msg, chunk);
+ list_add_tail(&chunk->frag_list, &msg->chunks);
+
+ /* The first chunk, the first chunk was likely short
+ * to allow bundling, so reset to full size.
+ */
+ if (0 == i)
+ len = max;
+ }
+
+ /* .. now the leftover bytes. */
+ if (over) {
+ if (!whole)
+ frag = SCTP_DATA_NOT_FRAG;
+ else
+ frag = SCTP_DATA_LAST_FRAG;
+
+ chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);
+
+ if (!chunk)
+ goto errout;
+
+ err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov);
+
+ /* Put the chunk->skb back into the form expected by send. */
+ __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
+ - (__u8 *)chunk->skb->data);
+ if (err < 0)
+ goto errout;
+
+ sctp_datamsg_assign(msg, chunk);
+ list_add_tail(&chunk->frag_list, &msg->chunks);
+ }
+
+ return msg;
+
+errout:
+ list_for_each_safe(pos, temp, &msg->chunks) {
+ list_del_init(pos);
+ chunk = list_entry(pos, struct sctp_chunk, frag_list);
+ sctp_chunk_free(chunk);
+ }
+ sctp_datamsg_free(msg);
+ return NULL;
+}
+
+/* Check whether this message has expired. */
+int sctp_chunk_abandoned(struct sctp_chunk *chunk)
+{
+ struct sctp_datamsg *msg = chunk->msg;
+
+ if (!msg->can_abandon)
+ return 0;
+
+ if (time_after(jiffies, msg->expires_at))
+ return 1;
+
+ return 0;
+}
+
+/* This chunk (and consequently entire message) has failed in its sending. */
+void sctp_chunk_fail(struct sctp_chunk *chunk, int error)
+{
+ chunk->msg->send_failed = 1;
+ chunk->msg->send_error = error;
+}
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