Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

Pull networking changes from David Miller:

 1) GRE now works over ipv6, from Dmitry Kozlov.

 2) Make SCTP more network namespace aware, from Eric Biederman.

 3) TEAM driver now works with non-ethernet devices, from Jiri Pirko.

 4) Make openvswitch network namespace aware, from Pravin B Shelar.

 5) IPV6 NAT implementation, from Patrick McHardy.

 6) Server side support for TCP Fast Open, from Jerry Chu and others.

 7) Packet BPF filter supports MOD and XOR, from Eric Dumazet and Daniel
    Borkmann.

 8) Increate the loopback default MTU to 64K, from Eric Dumazet.

 9) Use a per-task rather than per-socket page fragment allocator for
    outgoing networking traffic.  This benefits processes that have very
    many mostly idle sockets, which is quite common.

    From Eric Dumazet.

10) Use up to 32K for page fragment allocations, with fallbacks to
    smaller sizes when higher order page allocations fail.  Benefits are
    a) less segments for driver to process b) less calls to page
    allocator c) less waste of space.

    From Eric Dumazet.

11) Allow GRO to be used on GRE tunnels, from Eric Dumazet.

12) VXLAN device driver, one way to handle VLAN issues such as the
    limitation of 4096 VLAN IDs yet still have some level of isolation.
    From Stephen Hemminger.

13) As usual there is a large boatload of driver changes, with the scale
    perhaps tilted towards the wireless side this time around.

Fix up various fairly trivial conflicts, mostly caused by the user
namespace changes.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1012 commits)
  hyperv: Add buffer for extended info after the RNDIS response message.
  hyperv: Report actual status in receive completion packet
  hyperv: Remove extra allocated space for recv_pkt_list elements
  hyperv: Fix page buffer handling in rndis_filter_send_request()
  hyperv: Fix the missing return value in rndis_filter_set_packet_filter()
  hyperv: Fix the max_xfer_size in RNDIS initialization
  vxlan: put UDP socket in correct namespace
  vxlan: Depend on CONFIG_INET
  sfc: Fix the reported priorities of different filter types
  sfc: Remove EFX_FILTER_FLAG_RX_OVERRIDE_IP
  sfc: Fix loopback self-test with separate_tx_channels=1
  sfc: Fix MCDI structure field lookup
  sfc: Add parentheses around use of bitfield macro arguments
  sfc: Fix null function pointer in efx_sriov_channel_type
  vxlan: virtual extensible lan
  igmp: export symbol ip_mc_leave_group
  netlink: add attributes to fdb interface
  tg3: unconditionally select HWMON support when tg3 is enabled.
  Revert "net: ti cpsw ethernet: allow reading phy interface mode from DT"
  gre: fix sparse warning
  ...

1 files changed, 857 insertions, 0 deletions

diff --git a/net/nfc/hci/llc_shdlc.c b/net/nfc/hci/llc_shdlc.c
new file mode 100644
index 0000000..8f69d79
--- /dev/null
+++ b/net/nfc/hci/llc_shdlc.c
@@ -0,0 +1,857 @@
+/*
+ * shdlc Link Layer Control
+ *
+ * Copyright (C) 2012  Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * 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.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#define pr_fmt(fmt) "shdlc: %s: " fmt, __func__
+
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/slab.h>
+#include <linux/skbuff.h>
+
+#include "llc.h"
+
+enum shdlc_state {
+	SHDLC_DISCONNECTED = 0,
+	SHDLC_CONNECTING = 1,
+	SHDLC_NEGOTIATING = 2,
+	SHDLC_HALF_CONNECTED = 3,
+	SHDLC_CONNECTED = 4
+};
+
+struct llc_shdlc {
+	struct nfc_hci_dev *hdev;
+	xmit_to_drv_t xmit_to_drv;
+	rcv_to_hci_t rcv_to_hci;
+
+	struct mutex state_mutex;
+	enum shdlc_state state;
+	int hard_fault;
+
+	wait_queue_head_t *connect_wq;
+	int connect_tries;
+	int connect_result;
+	struct timer_list connect_timer;/* aka T3 in spec 10.6.1 */
+
+	u8 w;				/* window size */
+	bool srej_support;
+
+	struct timer_list t1_timer;	/* send ack timeout */
+	bool t1_active;
+
+	struct timer_list t2_timer;	/* guard/retransmit timeout */
+	bool t2_active;
+
+	int ns;				/* next seq num for send */
+	int nr;				/* next expected seq num for receive */
+	int dnr;			/* oldest sent unacked seq num */
+
+	struct sk_buff_head rcv_q;
+
+	struct sk_buff_head send_q;
+	bool rnr;			/* other side is not ready to receive */
+
+	struct sk_buff_head ack_pending_q;
+
+	struct work_struct sm_work;
+
+	int tx_headroom;
+	int tx_tailroom;
+
+	llc_failure_t llc_failure;
+};
+
+#define SHDLC_LLC_HEAD_ROOM	2
+
+#define SHDLC_MAX_WINDOW	4
+#define SHDLC_SREJ_SUPPORT	false
+
+#define SHDLC_CONTROL_HEAD_MASK	0xe0
+#define SHDLC_CONTROL_HEAD_I	0x80
+#define SHDLC_CONTROL_HEAD_I2	0xa0
+#define SHDLC_CONTROL_HEAD_S	0xc0
+#define SHDLC_CONTROL_HEAD_U	0xe0
+
+#define SHDLC_CONTROL_NS_MASK	0x38
+#define SHDLC_CONTROL_NR_MASK	0x07
+#define SHDLC_CONTROL_TYPE_MASK	0x18
+
+#define SHDLC_CONTROL_M_MASK	0x1f
+
+enum sframe_type {
+	S_FRAME_RR = 0x00,
+	S_FRAME_REJ = 0x01,
+	S_FRAME_RNR = 0x02,
+	S_FRAME_SREJ = 0x03
+};
+
+enum uframe_modifier {
+	U_FRAME_UA = 0x06,
+	U_FRAME_RSET = 0x19
+};
+
+#define SHDLC_CONNECT_VALUE_MS	5
+#define SHDLC_T1_VALUE_MS(w)	((5 * w) / 4)
+#define SHDLC_T2_VALUE_MS	300
+
+#define SHDLC_DUMP_SKB(info, skb)				  \
+do {								  \
+	pr_debug("%s:\n", info);				  \
+	print_hex_dump(KERN_DEBUG, "shdlc: ", DUMP_PREFIX_OFFSET, \
+		       16, 1, skb->data, skb->len, 0);		  \
+} while (0)
+
+/* checks x < y <= z modulo 8 */
+static bool llc_shdlc_x_lt_y_lteq_z(int x, int y, int z)
+{
+	if (x < z)
+		return ((x < y) && (y <= z)) ? true : false;
+	else
+		return ((y > x) || (y <= z)) ? true : false;
+}
+
+/* checks x <= y < z modulo 8 */
+static bool llc_shdlc_x_lteq_y_lt_z(int x, int y, int z)
+{
+	if (x <= z)
+		return ((x <= y) && (y < z)) ? true : false;
+	else			/* x > z -> z+8 > x */
+		return ((y >= x) || (y < z)) ? true : false;
+}
+
+static struct sk_buff *llc_shdlc_alloc_skb(struct llc_shdlc *shdlc,
+					   int payload_len)
+{
+	struct sk_buff *skb;
+
+	skb = alloc_skb(shdlc->tx_headroom + SHDLC_LLC_HEAD_ROOM +
+			shdlc->tx_tailroom + payload_len, GFP_KERNEL);
+	if (skb)
+		skb_reserve(skb, shdlc->tx_headroom + SHDLC_LLC_HEAD_ROOM);
+
+	return skb;
+}
+
+/* immediately sends an S frame. */
+static int llc_shdlc_send_s_frame(struct llc_shdlc *shdlc,
+				  enum sframe_type sframe_type, int nr)
+{
+	int r;
+	struct sk_buff *skb;
+
+	pr_debug("sframe_type=%d nr=%d\n", sframe_type, nr);
+
+	skb = llc_shdlc_alloc_skb(shdlc, 0);
+	if (skb == NULL)
+		return -ENOMEM;
+
+	*skb_push(skb, 1) = SHDLC_CONTROL_HEAD_S | (sframe_type << 3) | nr;
+
+	r = shdlc->xmit_to_drv(shdlc->hdev, skb);
+
+	kfree_skb(skb);
+
+	return r;
+}
+
+/* immediately sends an U frame. skb may contain optional payload */
+static int llc_shdlc_send_u_frame(struct llc_shdlc *shdlc,
+				  struct sk_buff *skb,
+				  enum uframe_modifier uframe_modifier)
+{
+	int r;
+
+	pr_debug("uframe_modifier=%d\n", uframe_modifier);
+
+	*skb_push(skb, 1) = SHDLC_CONTROL_HEAD_U | uframe_modifier;
+
+	r = shdlc->xmit_to_drv(shdlc->hdev, skb);
+
+	kfree_skb(skb);
+
+	return r;
+}
+
+/*
+ * Free ack_pending frames until y_nr - 1, and reset t2 according to
+ * the remaining oldest ack_pending frame sent time
+ */
+static void llc_shdlc_reset_t2(struct llc_shdlc *shdlc, int y_nr)
+{
+	struct sk_buff *skb;
+	int dnr = shdlc->dnr;	/* MUST initially be < y_nr */
+
+	pr_debug("release ack pending up to frame %d excluded\n", y_nr);
+
+	while (dnr != y_nr) {
+		pr_debug("release ack pending frame %d\n", dnr);
+
+		skb = skb_dequeue(&shdlc->ack_pending_q);
+		kfree_skb(skb);
+
+		dnr = (dnr + 1) % 8;
+	}
+
+	if (skb_queue_empty(&shdlc->ack_pending_q)) {
+		if (shdlc->t2_active) {
+			del_timer_sync(&shdlc->t2_timer);
+			shdlc->t2_active = false;
+
+			pr_debug
+			    ("All sent frames acked. Stopped T2(retransmit)\n");
+		}
+	} else {
+		skb = skb_peek(&shdlc->ack_pending_q);
+
+		mod_timer(&shdlc->t2_timer, *(unsigned long *)skb->cb +
+			  msecs_to_jiffies(SHDLC_T2_VALUE_MS));
+		shdlc->t2_active = true;
+
+		pr_debug
+		    ("Start T2(retransmit) for remaining unacked sent frames\n");
+	}
+}
+
+/*
+ * Receive validated frames from lower layer. skb contains HCI payload only.
+ * Handle according to algorithm at spec:10.8.2
+ */
+static void llc_shdlc_rcv_i_frame(struct llc_shdlc *shdlc,
+				  struct sk_buff *skb, int ns, int nr)
+{
+	int x_ns = ns;
+	int y_nr = nr;
+
+	pr_debug("recvd I-frame %d, remote waiting frame %d\n", ns, nr);
+
+	if (shdlc->state != SHDLC_CONNECTED)
+		goto exit;
+
+	if (x_ns != shdlc->nr) {
+		llc_shdlc_send_s_frame(shdlc, S_FRAME_REJ, shdlc->nr);
+		goto exit;
+	}
+
+	if (shdlc->t1_active == false) {
+		shdlc->t1_active = true;
+		mod_timer(&shdlc->t1_timer, jiffies +
+			  msecs_to_jiffies(SHDLC_T1_VALUE_MS(shdlc->w)));
+		pr_debug("(re)Start T1(send ack)\n");
+	}
+
+	if (skb->len) {
+		shdlc->rcv_to_hci(shdlc->hdev, skb);
+		skb = NULL;
+	}
+
+	shdlc->nr = (shdlc->nr + 1) % 8;
+
+	if (llc_shdlc_x_lt_y_lteq_z(shdlc->dnr, y_nr, shdlc->ns)) {
+		llc_shdlc_reset_t2(shdlc, y_nr);
+
+		shdlc->dnr = y_nr;
+	}
+
+exit:
+	kfree_skb(skb);
+}
+
+static void llc_shdlc_rcv_ack(struct llc_shdlc *shdlc, int y_nr)
+{
+	pr_debug("remote acked up to frame %d excluded\n", y_nr);
+
+	if (llc_shdlc_x_lt_y_lteq_z(shdlc->dnr, y_nr, shdlc->ns)) {
+		llc_shdlc_reset_t2(shdlc, y_nr);
+		shdlc->dnr = y_nr;
+	}
+}
+
+static void llc_shdlc_requeue_ack_pending(struct llc_shdlc *shdlc)
+{
+	struct sk_buff *skb;
+
+	pr_debug("ns reset to %d\n", shdlc->dnr);
+
+	while ((skb = skb_dequeue_tail(&shdlc->ack_pending_q))) {
+		skb_pull(skb, 1);	/* remove control field */
+		skb_queue_head(&shdlc->send_q, skb);
+	}
+	shdlc->ns = shdlc->dnr;
+}
+
+static void llc_shdlc_rcv_rej(struct llc_shdlc *shdlc, int y_nr)
+{
+	struct sk_buff *skb;
+
+	pr_debug("remote asks retransmition from frame %d\n", y_nr);
+
+	if (llc_shdlc_x_lteq_y_lt_z(shdlc->dnr, y_nr, shdlc->ns)) {
+		if (shdlc->t2_active) {
+			del_timer_sync(&shdlc->t2_timer);
+			shdlc->t2_active = false;
+			pr_debug("Stopped T2(retransmit)\n");
+		}
+
+		if (shdlc->dnr != y_nr) {
+			while ((shdlc->dnr = ((shdlc->dnr + 1) % 8)) != y_nr) {
+				skb = skb_dequeue(&shdlc->ack_pending_q);
+				kfree_skb(skb);
+			}
+		}
+
+		llc_shdlc_requeue_ack_pending(shdlc);
+	}
+}
+
+/* See spec RR:10.8.3 REJ:10.8.4 */
+static void llc_shdlc_rcv_s_frame(struct llc_shdlc *shdlc,
+				  enum sframe_type s_frame_type, int nr)
+{
+	struct sk_buff *skb;
+
+	if (shdlc->state != SHDLC_CONNECTED)
+		return;
+
+	switch (s_frame_type) {
+	case S_FRAME_RR:
+		llc_shdlc_rcv_ack(shdlc, nr);
+		if (shdlc->rnr == true) {	/* see SHDLC 10.7.7 */
+			shdlc->rnr = false;
+			if (shdlc->send_q.qlen == 0) {
+				skb = llc_shdlc_alloc_skb(shdlc, 0);
+				if (skb)
+					skb_queue_tail(&shdlc->send_q, skb);
+			}
+		}
+		break;
+	case S_FRAME_REJ:
+		llc_shdlc_rcv_rej(shdlc, nr);
+		break;
+	case S_FRAME_RNR:
+		llc_shdlc_rcv_ack(shdlc, nr);
+		shdlc->rnr = true;
+		break;
+	default:
+		break;
+	}
+}
+
+static void llc_shdlc_connect_complete(struct llc_shdlc *shdlc, int r)
+{
+	pr_debug("result=%d\n", r);
+
+	del_timer_sync(&shdlc->connect_timer);
+
+	if (r == 0) {
+		shdlc->ns = 0;
+		shdlc->nr = 0;
+		shdlc->dnr = 0;
+
+		shdlc->state = SHDLC_HALF_CONNECTED;
+	} else {
+		shdlc->state = SHDLC_DISCONNECTED;
+	}
+
+	shdlc->connect_result = r;
+
+	wake_up(shdlc->connect_wq);
+}
+
+static int llc_shdlc_connect_initiate(struct llc_shdlc *shdlc)
+{
+	struct sk_buff *skb;
+
+	pr_debug("\n");
+
+	skb = llc_shdlc_alloc_skb(shdlc, 2);
+	if (skb == NULL)
+		return -ENOMEM;
+
+	*skb_put(skb, 1) = SHDLC_MAX_WINDOW;
+	*skb_put(skb, 1) = SHDLC_SREJ_SUPPORT ? 1 : 0;
+
+	return llc_shdlc_send_u_frame(shdlc, skb, U_FRAME_RSET);
+}
+
+static int llc_shdlc_connect_send_ua(struct llc_shdlc *shdlc)
+{
+	struct sk_buff *skb;
+
+	pr_debug("\n");
+
+	skb = llc_shdlc_alloc_skb(shdlc, 0);
+	if (skb == NULL)
+		return -ENOMEM;
+
+	return llc_shdlc_send_u_frame(shdlc, skb, U_FRAME_UA);
+}
+
+static void llc_shdlc_rcv_u_frame(struct llc_shdlc *shdlc,
+				  struct sk_buff *skb,
+				  enum uframe_modifier u_frame_modifier)
+{
+	u8 w = SHDLC_MAX_WINDOW;
+	bool srej_support = SHDLC_SREJ_SUPPORT;
+	int r;
+
+	pr_debug("u_frame_modifier=%d\n", u_frame_modifier);
+
+	switch (u_frame_modifier) {
+	case U_FRAME_RSET:
+		switch (shdlc->state) {
+		case SHDLC_NEGOTIATING:
+		case SHDLC_CONNECTING:
+			/*
+			 * We sent RSET, but chip wants to negociate or we
+			 * got RSET before we managed to send out our.
+			 */
+			if (skb->len > 0)
+				w = skb->data[0];
+
+			if (skb->len > 1)
+				srej_support = skb->data[1] & 0x01 ? true :
+					       false;
+
+			if ((w <= SHDLC_MAX_WINDOW) &&
+			    (SHDLC_SREJ_SUPPORT || (srej_support == false))) {
+				shdlc->w = w;
+				shdlc->srej_support = srej_support;
+				r = llc_shdlc_connect_send_ua(shdlc);
+				llc_shdlc_connect_complete(shdlc, r);
+			}
+			break;
+		case SHDLC_HALF_CONNECTED:
+			/*
+			 * Chip resent RSET due to its timeout - Ignote it
+			 * as we already sent UA.
+			 */
+			break;
+		case SHDLC_CONNECTED:
+			/*
+			 * Chip wants to reset link. This is unexpected and
+			 * unsupported.
+			 */
+			shdlc->hard_fault = -ECONNRESET;
+			break;
+		default:
+			break;
+		}
+		break;
+	case U_FRAME_UA:
+		if ((shdlc->state == SHDLC_CONNECTING &&
+		     shdlc->connect_tries > 0) ||
+		    (shdlc->state == SHDLC_NEGOTIATING)) {
+			llc_shdlc_connect_complete(shdlc, 0);
+			shdlc->state = SHDLC_CONNECTED;
+		}
+		break;
+	default:
+		break;
+	}
+
+	kfree_skb(skb);
+}
+
+static void llc_shdlc_handle_rcv_queue(struct llc_shdlc *shdlc)
+{
+	struct sk_buff *skb;
+	u8 control;
+	int nr;
+	int ns;
+	enum sframe_type s_frame_type;
+	enum uframe_modifier u_frame_modifier;
+
+	if (shdlc->rcv_q.qlen)
+		pr_debug("rcvQlen=%d\n", shdlc->rcv_q.qlen);
+
+	while ((skb = skb_dequeue(&shdlc->rcv_q)) != NULL) {
+		control = skb->data[0];
+		skb_pull(skb, 1);
+		switch (control & SHDLC_CONTROL_HEAD_MASK) {
+		case SHDLC_CONTROL_HEAD_I:
+		case SHDLC_CONTROL_HEAD_I2:
+			if (shdlc->state == SHDLC_HALF_CONNECTED)
+				shdlc->state = SHDLC_CONNECTED;
+
+			ns = (control & SHDLC_CONTROL_NS_MASK) >> 3;
+			nr = control & SHDLC_CONTROL_NR_MASK;
+			llc_shdlc_rcv_i_frame(shdlc, skb, ns, nr);
+			break;
+		case SHDLC_CONTROL_HEAD_S:
+			if (shdlc->state == SHDLC_HALF_CONNECTED)
+				shdlc->state = SHDLC_CONNECTED;
+
+			s_frame_type = (control & SHDLC_CONTROL_TYPE_MASK) >> 3;
+			nr = control & SHDLC_CONTROL_NR_MASK;
+			llc_shdlc_rcv_s_frame(shdlc, s_frame_type, nr);
+			kfree_skb(skb);
+			break;
+		case SHDLC_CONTROL_HEAD_U:
+			u_frame_modifier = control & SHDLC_CONTROL_M_MASK;
+			llc_shdlc_rcv_u_frame(shdlc, skb, u_frame_modifier);
+			break;
+		default:
+			pr_err("UNKNOWN Control=%d\n", control);
+			kfree_skb(skb);
+			break;
+		}
+	}
+}
+
+static int llc_shdlc_w_used(int ns, int dnr)
+{
+	int unack_count;
+
+	if (dnr <= ns)
+		unack_count = ns - dnr;
+	else
+		unack_count = 8 - dnr + ns;
+
+	return unack_count;
+}
+
+/* Send frames according to algorithm at spec:10.8.1 */
+static void llc_shdlc_handle_send_queue(struct llc_shdlc *shdlc)
+{
+	struct sk_buff *skb;
+	int r;
+	unsigned long time_sent;
+
+	if (shdlc->send_q.qlen)
+		pr_debug
+		    ("sendQlen=%d ns=%d dnr=%d rnr=%s w_room=%d unackQlen=%d\n",
+		     shdlc->send_q.qlen, shdlc->ns, shdlc->dnr,
+		     shdlc->rnr == false ? "false" : "true",
+		     shdlc->w - llc_shdlc_w_used(shdlc->ns, shdlc->dnr),
+		     shdlc->ack_pending_q.qlen);
+
+	while (shdlc->send_q.qlen && shdlc->ack_pending_q.qlen < shdlc->w &&
+	       (shdlc->rnr == false)) {
+
+		if (shdlc->t1_active) {
+			del_timer_sync(&shdlc->t1_timer);
+			shdlc->t1_active = false;
+			pr_debug("Stopped T1(send ack)\n");
+		}
+
+		skb = skb_dequeue(&shdlc->send_q);
+
+		*skb_push(skb, 1) = SHDLC_CONTROL_HEAD_I | (shdlc->ns << 3) |
+				    shdlc->nr;
+
+		pr_debug("Sending I-Frame %d, waiting to rcv %d\n", shdlc->ns,
+			 shdlc->nr);
+		SHDLC_DUMP_SKB("shdlc frame written", skb);
+
+		r = shdlc->xmit_to_drv(shdlc->hdev, skb);
+		if (r < 0) {
+			shdlc->hard_fault = r;
+			break;
+		}
+
+		shdlc->ns = (shdlc->ns + 1) % 8;
+
+		time_sent = jiffies;
+		*(unsigned long *)skb->cb = time_sent;
+
+		skb_queue_tail(&shdlc->ack_pending_q, skb);
+
+		if (shdlc->t2_active == false) {
+			shdlc->t2_active = true;
+			mod_timer(&shdlc->t2_timer, time_sent +
+				  msecs_to_jiffies(SHDLC_T2_VALUE_MS));
+			pr_debug("Started T2 (retransmit)\n");
+		}
+	}
+}
+
+static void llc_shdlc_connect_timeout(unsigned long data)
+{
+	struct llc_shdlc *shdlc = (struct llc_shdlc *)data;
+
+	pr_debug("\n");
+
+	queue_work(system_nrt_wq, &shdlc->sm_work);
+}
+
+static void llc_shdlc_t1_timeout(unsigned long data)
+{
+	struct llc_shdlc *shdlc = (struct llc_shdlc *)data;
+
+	pr_debug("SoftIRQ: need to send ack\n");
+
+	queue_work(system_nrt_wq, &shdlc->sm_work);
+}
+
+static void llc_shdlc_t2_timeout(unsigned long data)
+{
+	struct llc_shdlc *shdlc = (struct llc_shdlc *)data;
+
+	pr_debug("SoftIRQ: need to retransmit\n");
+
+	queue_work(system_nrt_wq, &shdlc->sm_work);
+}
+
+static void llc_shdlc_sm_work(struct work_struct *work)
+{
+	struct llc_shdlc *shdlc = container_of(work, struct llc_shdlc, sm_work);
+	int r;
+
+	pr_debug("\n");
+
+	mutex_lock(&shdlc->state_mutex);
+
+	switch (shdlc->state) {
+	case SHDLC_DISCONNECTED:
+		skb_queue_purge(&shdlc->rcv_q);
+		skb_queue_purge(&shdlc->send_q);
+		skb_queue_purge(&shdlc->ack_pending_q);
+		break;
+	case SHDLC_CONNECTING:
+		if (shdlc->hard_fault) {
+			llc_shdlc_connect_complete(shdlc, shdlc->hard_fault);
+			break;
+		}
+
+		if (shdlc->connect_tries++ < 5)
+			r = llc_shdlc_connect_initiate(shdlc);
+		else
+			r = -ETIME;
+		if (r < 0)
+			llc_shdlc_connect_complete(shdlc, r);
+		else {
+			mod_timer(&shdlc->connect_timer, jiffies +
+				  msecs_to_jiffies(SHDLC_CONNECT_VALUE_MS));
+
+			shdlc->state = SHDLC_NEGOTIATING;
+		}
+		break;
+	case SHDLC_NEGOTIATING:
+		if (timer_pending(&shdlc->connect_timer) == 0) {
+			shdlc->state = SHDLC_CONNECTING;
+			queue_work(system_nrt_wq, &shdlc->sm_work);
+		}
+
+		llc_shdlc_handle_rcv_queue(shdlc);
+
+		if (shdlc->hard_fault) {
+			llc_shdlc_connect_complete(shdlc, shdlc->hard_fault);
+			break;
+		}
+		break;
+	case SHDLC_HALF_CONNECTED:
+	case SHDLC_CONNECTED:
+		llc_shdlc_handle_rcv_queue(shdlc);
+		llc_shdlc_handle_send_queue(shdlc);
+
+		if (shdlc->t1_active && timer_pending(&shdlc->t1_timer) == 0) {
+			pr_debug
+			    ("Handle T1(send ack) elapsed (T1 now inactive)\n");
+
+			shdlc->t1_active = false;
+			r = llc_shdlc_send_s_frame(shdlc, S_FRAME_RR,
+						   shdlc->nr);
+			if (r < 0)
+				shdlc->hard_fault = r;
+		}
+
+		if (shdlc->t2_active && timer_pending(&shdlc->t2_timer) == 0) {
+			pr_debug
+			    ("Handle T2(retransmit) elapsed (T2 inactive)\n");
+
+			shdlc->t2_active = false;
+
+			llc_shdlc_requeue_ack_pending(shdlc);
+			llc_shdlc_handle_send_queue(shdlc);
+		}
+
+		if (shdlc->hard_fault) {
+			shdlc->llc_failure(shdlc->hdev, shdlc->hard_fault);
+		}
+		break;
+	default:
+		break;
+	}
+	mutex_unlock(&shdlc->state_mutex);
+}
+
+/*
+ * Called from syscall context to establish shdlc link. Sleeps until
+ * link is ready or failure.
+ */
+static int llc_shdlc_connect(struct llc_shdlc *shdlc)
+{
+	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(connect_wq);
+
+	pr_debug("\n");
+
+	mutex_lock(&shdlc->state_mutex);
+
+	shdlc->state = SHDLC_CONNECTING;
+	shdlc->connect_wq = &connect_wq;
+	shdlc->connect_tries = 0;
+	shdlc->connect_result = 1;
+
+	mutex_unlock(&shdlc->state_mutex);
+
+	queue_work(system_nrt_wq, &shdlc->sm_work);
+
+	wait_event(connect_wq, shdlc->connect_result != 1);
+
+	return shdlc->connect_result;
+}
+
+static void llc_shdlc_disconnect(struct llc_shdlc *shdlc)
+{
+	pr_debug("\n");
+
+	mutex_lock(&shdlc->state_mutex);
+
+	shdlc->state = SHDLC_DISCONNECTED;
+
+	mutex_unlock(&shdlc->state_mutex);
+
+	queue_work(system_nrt_wq, &shdlc->sm_work);
+}
+
+/*
+ * Receive an incoming shdlc frame. Frame has already been crc-validated.
+ * skb contains only LLC header and payload.
+ * If skb == NULL, it is a notification that the link below is dead.
+ */
+static void llc_shdlc_recv_frame(struct llc_shdlc *shdlc, struct sk_buff *skb)
+{
+	if (skb == NULL) {
+		pr_err("NULL Frame -> link is dead\n");
+		shdlc->hard_fault = -EREMOTEIO;
+	} else {
+		SHDLC_DUMP_SKB("incoming frame", skb);
+		skb_queue_tail(&shdlc->rcv_q, skb);
+	}
+
+	queue_work(system_nrt_wq, &shdlc->sm_work);
+}
+
+static void *llc_shdlc_init(struct nfc_hci_dev *hdev, xmit_to_drv_t xmit_to_drv,
+			    rcv_to_hci_t rcv_to_hci, int tx_headroom,
+			    int tx_tailroom, int *rx_headroom, int *rx_tailroom,
+			    llc_failure_t llc_failure)
+{
+	struct llc_shdlc *shdlc;
+
+	*rx_headroom = SHDLC_LLC_HEAD_ROOM;
+	*rx_tailroom = 0;
+
+	shdlc = kzalloc(sizeof(struct llc_shdlc), GFP_KERNEL);
+	if (shdlc == NULL)
+		return NULL;
+
+	mutex_init(&shdlc->state_mutex);
+	shdlc->state = SHDLC_DISCONNECTED;
+
+	init_timer(&shdlc->connect_timer);
+	shdlc->connect_timer.data = (unsigned long)shdlc;
+	shdlc->connect_timer.function = llc_shdlc_connect_timeout;
+
+	init_timer(&shdlc->t1_timer);
+	shdlc->t1_timer.data = (unsigned long)shdlc;
+	shdlc->t1_timer.function = llc_shdlc_t1_timeout;
+
+	init_timer(&shdlc->t2_timer);
+	shdlc->t2_timer.data = (unsigned long)shdlc;
+	shdlc->t2_timer.function = llc_shdlc_t2_timeout;
+
+	shdlc->w = SHDLC_MAX_WINDOW;
+	shdlc->srej_support = SHDLC_SREJ_SUPPORT;
+
+	skb_queue_head_init(&shdlc->rcv_q);
+	skb_queue_head_init(&shdlc->send_q);
+	skb_queue_head_init(&shdlc->ack_pending_q);
+
+	INIT_WORK(&shdlc->sm_work, llc_shdlc_sm_work);
+
+	shdlc->hdev = hdev;
+	shdlc->xmit_to_drv = xmit_to_drv;
+	shdlc->rcv_to_hci = rcv_to_hci;
+	shdlc->tx_headroom = tx_headroom;
+	shdlc->tx_tailroom = tx_tailroom;
+	shdlc->llc_failure = llc_failure;
+
+	return shdlc;
+}
+
+static void llc_shdlc_deinit(struct nfc_llc *llc)
+{
+	struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
+
+	skb_queue_purge(&shdlc->rcv_q);
+	skb_queue_purge(&shdlc->send_q);
+	skb_queue_purge(&shdlc->ack_pending_q);
+
+	kfree(shdlc);
+}
+
+static int llc_shdlc_start(struct nfc_llc *llc)
+{
+	struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
+
+	return llc_shdlc_connect(shdlc);
+}
+
+static int llc_shdlc_stop(struct nfc_llc *llc)
+{
+	struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
+
+	llc_shdlc_disconnect(shdlc);
+
+	return 0;
+}
+
+static void llc_shdlc_rcv_from_drv(struct nfc_llc *llc, struct sk_buff *skb)
+{
+	struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
+
+	llc_shdlc_recv_frame(shdlc, skb);
+}
+
+static int llc_shdlc_xmit_from_hci(struct nfc_llc *llc, struct sk_buff *skb)
+{
+	struct llc_shdlc *shdlc = nfc_llc_get_data(llc);
+
+	skb_queue_tail(&shdlc->send_q, skb);
+
+	queue_work(system_nrt_wq, &shdlc->sm_work);
+
+	return 0;
+}
+
+static struct nfc_llc_ops llc_shdlc_ops = {
+	.init = llc_shdlc_init,
+	.deinit = llc_shdlc_deinit,
+	.start = llc_shdlc_start,
+	.stop = llc_shdlc_stop,
+	.rcv_from_drv = llc_shdlc_rcv_from_drv,
+	.xmit_from_hci = llc_shdlc_xmit_from_hci,
+};
+
+int nfc_llc_shdlc_register(void)
+{
+	return nfc_llc_register(LLC_SHDLC_NAME, &llc_shdlc_ops);
+}