1 files changed, 864 insertions, 1167 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
index eaa9fe5..75db07c 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -48,9 +48,8 @@
 /*
  * Error message prefixes
  */
-static const char *link_co_err = "Link changeover error, ";
+static const char *link_co_err = "Link tunneling error, ";
 static const char *link_rst_msg = "Resetting link ";
-static const char *link_unk_evt = "Unknown link event ";
 
 static const struct nla_policy tipc_nl_link_policy[TIPC_NLA_LINK_MAX + 1] = {
 	[TIPC_NLA_LINK_UNSPEC]		= { .type = NLA_UNSPEC },
@@ -77,256 +76,413 @@ static const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
 };
 
 /*
+ * Interval between NACKs when packets arrive out of order
+ */
+#define TIPC_NACK_INTV (TIPC_MIN_LINK_WIN * 2)
+/*
  * Out-of-range value for link session numbers
  */
-#define INVALID_SESSION 0x10000
+#define WILDCARD_SESSION 0x10000
 
-/*
- * Link state events:
+/* Link FSM states:
  */
-#define  STARTING_EVT    856384768	/* link processing trigger */
-#define  TRAFFIC_MSG_EVT 560815u	/* rx'd ??? */
-#define  SILENCE_EVT     560817u	/* timer dicovered silence from peer */
+enum {
+	LINK_ESTABLISHED     = 0xe,
+	LINK_ESTABLISHING    = 0xe  << 4,
+	LINK_RESET           = 0x1  << 8,
+	LINK_RESETTING       = 0x2  << 12,
+	LINK_PEER_RESET      = 0xd  << 16,
+	LINK_FAILINGOVER     = 0xf  << 20,
+	LINK_SYNCHING        = 0xc  << 24
+};
 
-/*
- * State value stored in 'failover_pkts'
+/* Link FSM state checking routines
  */
-#define FIRST_FAILOVER 0xffffu
-
-static void link_handle_out_of_seq_msg(struct tipc_link *link,
-				       struct sk_buff *skb);
-static void tipc_link_proto_rcv(struct tipc_link *link,
-				struct sk_buff *skb);
-static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol);
-static void link_state_event(struct tipc_link *l_ptr, u32 event);
+static int link_is_up(struct tipc_link *l)
+{
+	return l->state & (LINK_ESTABLISHED | LINK_SYNCHING);
+}
+
+static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
+			       struct sk_buff_head *xmitq);
+static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
+				      u16 rcvgap, int tolerance, int priority,
+				      struct sk_buff_head *xmitq);
 static void link_reset_statistics(struct tipc_link *l_ptr);
 static void link_print(struct tipc_link *l_ptr, const char *str);
-static void tipc_link_sync_xmit(struct tipc_link *l);
 static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf);
-static void tipc_link_input(struct tipc_link *l, struct sk_buff *skb);
-static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb);
-static bool tipc_link_failover_rcv(struct tipc_link *l, struct sk_buff **skb);
-static void link_set_timer(struct tipc_link *link, unsigned long time);
+
 /*
- *  Simple link routines
+ *  Simple non-static link routines (i.e. referenced outside this file)
  */
-static unsigned int align(unsigned int i)
+bool tipc_link_is_up(struct tipc_link *l)
 {
-	return (i + 3) & ~3u;
+	return link_is_up(l);
 }
 
-static void tipc_link_release(struct kref *kref)
+bool tipc_link_is_reset(struct tipc_link *l)
 {
-	kfree(container_of(kref, struct tipc_link, ref));
+	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
 }
 
-static void tipc_link_get(struct tipc_link *l_ptr)
+bool tipc_link_is_synching(struct tipc_link *l)
 {
-	kref_get(&l_ptr->ref);
+	return l->state == LINK_SYNCHING;
 }
 
-static void tipc_link_put(struct tipc_link *l_ptr)
+bool tipc_link_is_failingover(struct tipc_link *l)
 {
-	kref_put(&l_ptr->ref, tipc_link_release);
+	return l->state == LINK_FAILINGOVER;
 }
 
-static struct tipc_link *tipc_parallel_link(struct tipc_link *l)
+bool tipc_link_is_blocked(struct tipc_link *l)
 {
-	if (l->owner->active_links[0] != l)
-		return l->owner->active_links[0];
-	return l->owner->active_links[1];
+	return l->state & (LINK_RESETTING | LINK_PEER_RESET | LINK_FAILINGOVER);
 }
 
-/*
- *  Simple non-static link routines (i.e. referenced outside this file)
- */
-int tipc_link_is_up(struct tipc_link *l_ptr)
+int tipc_link_is_active(struct tipc_link *l)
 {
-	if (!l_ptr)
-		return 0;
-	return link_working_working(l_ptr) || link_working_unknown(l_ptr);
+	struct tipc_node *n = l->owner;
+
+	return (node_active_link(n, 0) == l) || (node_active_link(n, 1) == l);
 }
 
-int tipc_link_is_active(struct tipc_link *l_ptr)
+static u32 link_own_addr(struct tipc_link *l)
 {
-	return	(l_ptr->owner->active_links[0] == l_ptr) ||
-		(l_ptr->owner->active_links[1] == l_ptr);
+	return msg_prevnode(l->pmsg);
 }
 
 /**
- * link_timeout - handle expiration of link timer
- * @l_ptr: pointer to link
+ * tipc_link_create - create a new link
+ * @n: pointer to associated node
+ * @b: pointer to associated bearer
+ * @ownnode: identity of own node
+ * @peer: identity of peer node
+ * @maddr: media address to be used
+ * @inputq: queue to put messages ready for delivery
+ * @namedq: queue to put binding table update messages ready for delivery
+ * @link: return value, pointer to put the created link
+ *
+ * Returns true if link was created, otherwise false
  */
-static void link_timeout(unsigned long data)
+bool tipc_link_create(struct tipc_node *n, struct tipc_bearer *b, u32 session,
+		      u32 ownnode, u32 peer, struct tipc_media_addr *maddr,
+		      struct sk_buff_head *inputq, struct sk_buff_head *namedq,
+		      struct tipc_link **link)
 {
-	struct tipc_link *l_ptr = (struct tipc_link *)data;
-	struct sk_buff *skb;
+	struct tipc_link *l;
+	struct tipc_msg *hdr;
+	char *if_name;
+
+	l = kzalloc(sizeof(*l), GFP_ATOMIC);
+	if (!l)
+		return false;
+	*link = l;
+
+	/* Note: peer i/f name is completed by reset/activate message */
+	if_name = strchr(b->name, ':') + 1;
+	sprintf(l->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
+		tipc_zone(ownnode), tipc_cluster(ownnode), tipc_node(ownnode),
+		if_name, tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
+
+	l->addr = peer;
+	l->media_addr = maddr;
+	l->owner = n;
+	l->peer_session = WILDCARD_SESSION;
+	l->bearer_id = b->identity;
+	l->tolerance = b->tolerance;
+	l->net_plane = b->net_plane;
+	l->advertised_mtu = b->mtu;
+	l->mtu = b->mtu;
+	l->priority = b->priority;
+	tipc_link_set_queue_limits(l, b->window);
+	l->inputq = inputq;
+	l->namedq = namedq;
+	l->state = LINK_RESETTING;
+	l->pmsg = (struct tipc_msg *)&l->proto_msg;
+	hdr = l->pmsg;
+	tipc_msg_init(ownnode, hdr, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, peer);
+	msg_set_size(hdr, sizeof(l->proto_msg));
+	msg_set_session(hdr, session);
+	msg_set_bearer_id(hdr, l->bearer_id);
+	strcpy((char *)msg_data(hdr), if_name);
+	__skb_queue_head_init(&l->transmq);
+	__skb_queue_head_init(&l->backlogq);
+	__skb_queue_head_init(&l->deferdq);
+	skb_queue_head_init(&l->wakeupq);
+	skb_queue_head_init(l->inputq);
+	return true;
+}
 
-	tipc_node_lock(l_ptr->owner);
+/* tipc_link_build_bcast_sync_msg() - synchronize broadcast link endpoints.
+ *
+ * Give a newly added peer node the sequence number where it should
+ * start receiving and acking broadcast packets.
+ */
+void tipc_link_build_bcast_sync_msg(struct tipc_link *l,
+				    struct sk_buff_head *xmitq)
+{
+	struct sk_buff *skb;
+	struct sk_buff_head list;
+	u16 last_sent;
 
-	/* update counters used in statistical profiling of send traffic */
-	l_ptr->stats.accu_queue_sz += skb_queue_len(&l_ptr->transmq);
-	l_ptr->stats.queue_sz_counts++;
+	skb = tipc_msg_create(BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE,
+			      0, l->addr, link_own_addr(l), 0, 0, 0);
+	if (!skb)
+		return;
+	last_sent = tipc_bclink_get_last_sent(l->owner->net);
+	msg_set_last_bcast(buf_msg(skb), last_sent);
+	__skb_queue_head_init(&list);
+	__skb_queue_tail(&list, skb);
+	tipc_link_xmit(l, &list, xmitq);
+}
 
-	skb = skb_peek(&l_ptr->transmq);
-	if (skb) {
-		struct tipc_msg *msg = buf_msg(skb);
-		u32 length = msg_size(msg);
+/**
+ * tipc_link_fsm_evt - link finite state machine
+ * @l: pointer to link
+ * @evt: state machine event to be processed
+ */
+int tipc_link_fsm_evt(struct tipc_link *l, int evt)
+{
+	int rc = 0;
 
-		if ((msg_user(msg) == MSG_FRAGMENTER) &&
-		    (msg_type(msg) == FIRST_FRAGMENT)) {
-			length = msg_size(msg_get_wrapped(msg));
+	switch (l->state) {
+	case LINK_RESETTING:
+		switch (evt) {
+		case LINK_PEER_RESET_EVT:
+			l->state = LINK_PEER_RESET;
+			break;
+		case LINK_RESET_EVT:
+			l->state = LINK_RESET;
+			break;
+		case LINK_FAILURE_EVT:
+		case LINK_FAILOVER_BEGIN_EVT:
+		case LINK_ESTABLISH_EVT:
+		case LINK_FAILOVER_END_EVT:
+		case LINK_SYNCH_BEGIN_EVT:
+		case LINK_SYNCH_END_EVT:
+		default:
+			goto illegal_evt;
 		}
-		if (length) {
-			l_ptr->stats.msg_lengths_total += length;
-			l_ptr->stats.msg_length_counts++;
-			if (length <= 64)
-				l_ptr->stats.msg_length_profile[0]++;
-			else if (length <= 256)
-				l_ptr->stats.msg_length_profile[1]++;
-			else if (length <= 1024)
-				l_ptr->stats.msg_length_profile[2]++;
-			else if (length <= 4096)
-				l_ptr->stats.msg_length_profile[3]++;
-			else if (length <= 16384)
-				l_ptr->stats.msg_length_profile[4]++;
-			else if (length <= 32768)
-				l_ptr->stats.msg_length_profile[5]++;
-			else
-				l_ptr->stats.msg_length_profile[6]++;
+		break;
+	case LINK_RESET:
+		switch (evt) {
+		case LINK_PEER_RESET_EVT:
+			l->state = LINK_ESTABLISHING;
+			break;
+		case LINK_FAILOVER_BEGIN_EVT:
+			l->state = LINK_FAILINGOVER;
+		case LINK_FAILURE_EVT:
+		case LINK_RESET_EVT:
+		case LINK_ESTABLISH_EVT:
+		case LINK_FAILOVER_END_EVT:
+			break;
+		case LINK_SYNCH_BEGIN_EVT:
+		case LINK_SYNCH_END_EVT:
+		default:
+			goto illegal_evt;
+		}
+		break;
+	case LINK_PEER_RESET:
+		switch (evt) {
+		case LINK_RESET_EVT:
+			l->state = LINK_ESTABLISHING;
+			break;
+		case LINK_PEER_RESET_EVT:
+		case LINK_ESTABLISH_EVT:
+		case LINK_FAILURE_EVT:
+			break;
+		case LINK_SYNCH_BEGIN_EVT:
+		case LINK_SYNCH_END_EVT:
+		case LINK_FAILOVER_BEGIN_EVT:
+		case LINK_FAILOVER_END_EVT:
+		default:
+			goto illegal_evt;
 		}
+		break;
+	case LINK_FAILINGOVER:
+		switch (evt) {
+		case LINK_FAILOVER_END_EVT:
+			l->state = LINK_RESET;
+			break;
+		case LINK_PEER_RESET_EVT:
+		case LINK_RESET_EVT:
+		case LINK_ESTABLISH_EVT:
+		case LINK_FAILURE_EVT:
+			break;
+		case LINK_FAILOVER_BEGIN_EVT:
+		case LINK_SYNCH_BEGIN_EVT:
+		case LINK_SYNCH_END_EVT:
+		default:
+			goto illegal_evt;
+		}
+		break;
+	case LINK_ESTABLISHING:
+		switch (evt) {
+		case LINK_ESTABLISH_EVT:
+			l->state = LINK_ESTABLISHED;
+			rc |= TIPC_LINK_UP_EVT;
+			break;
+		case LINK_FAILOVER_BEGIN_EVT:
+			l->state = LINK_FAILINGOVER;
+			break;
+		case LINK_PEER_RESET_EVT:
+		case LINK_RESET_EVT:
+		case LINK_FAILURE_EVT:
+		case LINK_SYNCH_BEGIN_EVT:
+		case LINK_FAILOVER_END_EVT:
+			break;
+		case LINK_SYNCH_END_EVT:
+		default:
+			goto illegal_evt;
+		}
+		break;
+	case LINK_ESTABLISHED:
+		switch (evt) {
+		case LINK_PEER_RESET_EVT:
+			l->state = LINK_PEER_RESET;
+			rc |= TIPC_LINK_DOWN_EVT;
+			break;
+		case LINK_FAILURE_EVT:
+			l->state = LINK_RESETTING;
+			rc |= TIPC_LINK_DOWN_EVT;
+			break;
+		case LINK_RESET_EVT:
+			l->state = LINK_RESET;
+			break;
+		case LINK_ESTABLISH_EVT:
+		case LINK_SYNCH_END_EVT:
+			break;
+		case LINK_SYNCH_BEGIN_EVT:
+			l->state = LINK_SYNCHING;
+			break;
+		case LINK_FAILOVER_BEGIN_EVT:
+		case LINK_FAILOVER_END_EVT:
+		default:
+			goto illegal_evt;
+		}
+		break;
+	case LINK_SYNCHING:
+		switch (evt) {
+		case LINK_PEER_RESET_EVT:
+			l->state = LINK_PEER_RESET;
+			rc |= TIPC_LINK_DOWN_EVT;
+			break;
+		case LINK_FAILURE_EVT:
+			l->state = LINK_RESETTING;
+			rc |= TIPC_LINK_DOWN_EVT;
+			break;
+		case LINK_RESET_EVT:
+			l->state = LINK_RESET;
+			break;
+		case LINK_ESTABLISH_EVT:
+		case LINK_SYNCH_BEGIN_EVT:
+			break;
+		case LINK_SYNCH_END_EVT:
+			l->state = LINK_ESTABLISHED;
+			break;
+		case LINK_FAILOVER_BEGIN_EVT:
+		case LINK_FAILOVER_END_EVT:
+		default:
+			goto illegal_evt;
+		}
+		break;
+	default:
+		pr_err("Unknown FSM state %x in %s\n", l->state, l->name);
 	}
-
-	/* do all other link processing performed on a periodic basis */
-	if (l_ptr->silent_intv_cnt || tipc_bclink_acks_missing(l_ptr->owner))
-		link_state_event(l_ptr, SILENCE_EVT);
-	l_ptr->silent_intv_cnt++;
-	if (skb_queue_len(&l_ptr->backlogq))
-		tipc_link_push_packets(l_ptr);
-	link_set_timer(l_ptr, l_ptr->keepalive_intv);
-	tipc_node_unlock(l_ptr->owner);
-	tipc_link_put(l_ptr);
-}
-
-static void link_set_timer(struct tipc_link *link, unsigned long time)
-{
-	if (!mod_timer(&link->timer, jiffies + time))
-		tipc_link_get(link);
+	return rc;
+illegal_evt:
+	pr_err("Illegal FSM event %x in state %x on link %s\n",
+	       evt, l->state, l->name);
+	return rc;
 }
 
-/**
- * tipc_link_create - create a new link
- * @n_ptr: pointer to associated node
- * @b_ptr: pointer to associated bearer
- * @media_addr: media address to use when sending messages over link
- *
- * Returns pointer to link.
+/* link_profile_stats - update statistical profiling of traffic
  */
-struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
-				   struct tipc_bearer *b_ptr,
-				   const struct tipc_media_addr *media_addr)
+static void link_profile_stats(struct tipc_link *l)
 {
-	struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
-	struct tipc_link *l_ptr;
+	struct sk_buff *skb;
 	struct tipc_msg *msg;
-	char *if_name;
-	char addr_string[16];
-	u32 peer = n_ptr->addr;
+	int length;
 
-	if (n_ptr->link_cnt >= MAX_BEARERS) {
-		tipc_addr_string_fill(addr_string, n_ptr->addr);
-		pr_err("Cannot establish %uth link to %s. Max %u allowed.\n",
-		       n_ptr->link_cnt, addr_string, MAX_BEARERS);
-		return NULL;
-	}
+	/* Update counters used in statistical profiling of send traffic */
+	l->stats.accu_queue_sz += skb_queue_len(&l->transmq);
+	l->stats.queue_sz_counts++;
 
-	if (n_ptr->links[b_ptr->identity]) {
-		tipc_addr_string_fill(addr_string, n_ptr->addr);
-		pr_err("Attempt to establish second link on <%s> to %s\n",
-		       b_ptr->name, addr_string);
-		return NULL;
-	}
+	skb = skb_peek(&l->transmq);
+	if (!skb)
+		return;
+	msg = buf_msg(skb);
+	length = msg_size(msg);
 
-	l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
-	if (!l_ptr) {
-		pr_warn("Link creation failed, no memory\n");
-		return NULL;
+	if (msg_user(msg) == MSG_FRAGMENTER) {
+		if (msg_type(msg) != FIRST_FRAGMENT)
+			return;
+		length = msg_size(msg_get_wrapped(msg));
 	}
-	kref_init(&l_ptr->ref);
-	l_ptr->addr = peer;
-	if_name = strchr(b_ptr->name, ':') + 1;
-	sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
-		tipc_zone(tn->own_addr), tipc_cluster(tn->own_addr),
-		tipc_node(tn->own_addr),
-		if_name,
-		tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
-		/* note: peer i/f name is updated by reset/activate message */
-	memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
-	l_ptr->owner = n_ptr;
-	l_ptr->peer_session = INVALID_SESSION;
-	l_ptr->bearer_id = b_ptr->identity;
-	link_set_supervision_props(l_ptr, b_ptr->tolerance);
-	l_ptr->state = RESET_UNKNOWN;
-
-	l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
-	msg = l_ptr->pmsg;
-	tipc_msg_init(tn->own_addr, msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE,
-		      l_ptr->addr);
-	msg_set_size(msg, sizeof(l_ptr->proto_msg));
-	msg_set_session(msg, (tn->random & 0xffff));
-	msg_set_bearer_id(msg, b_ptr->identity);
-	strcpy((char *)msg_data(msg), if_name);
-	l_ptr->net_plane = b_ptr->net_plane;
-	l_ptr->advertised_mtu = b_ptr->mtu;
-	l_ptr->mtu = l_ptr->advertised_mtu;
-	l_ptr->priority = b_ptr->priority;
-	tipc_link_set_queue_limits(l_ptr, b_ptr->window);
-	l_ptr->snd_nxt = 1;
-	__skb_queue_head_init(&l_ptr->transmq);
-	__skb_queue_head_init(&l_ptr->backlogq);
-	__skb_queue_head_init(&l_ptr->deferdq);
-	skb_queue_head_init(&l_ptr->wakeupq);
-	skb_queue_head_init(&l_ptr->inputq);
-	skb_queue_head_init(&l_ptr->namedq);
-	link_reset_statistics(l_ptr);
-	tipc_node_attach_link(n_ptr, l_ptr);
-	setup_timer(&l_ptr->timer, link_timeout, (unsigned long)l_ptr);
-	link_state_event(l_ptr, STARTING_EVT);
-
-	return l_ptr;
+	l->stats.msg_lengths_total += length;
+	l->stats.msg_length_counts++;
+	if (length <= 64)
+		l->stats.msg_length_profile[0]++;
+	else if (length <= 256)
+		l->stats.msg_length_profile[1]++;
+	else if (length <= 1024)
+		l->stats.msg_length_profile[2]++;
+	else if (length <= 4096)
+		l->stats.msg_length_profile[3]++;
+	else if (length <= 16384)
+		l->stats.msg_length_profile[4]++;
+	else if (length <= 32768)
+		l->stats.msg_length_profile[5]++;
+	else
+		l->stats.msg_length_profile[6]++;
 }
 
-/**
- * tipc_link_delete - Delete a link
- * @l: link to be deleted
+/* tipc_link_timeout - perform periodic task as instructed from node timeout
  */
-void tipc_link_delete(struct tipc_link *l)
+int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq)
 {
-	tipc_link_reset(l);
-	if (del_timer(&l->timer))
-		tipc_link_put(l);
-	l->flags |= LINK_STOPPED;
-	/* Delete link now, or when timer is finished: */
-	tipc_link_reset_fragments(l);
-	tipc_node_detach_link(l->owner, l);
-	tipc_link_put(l);
-}
+	int rc = 0;
+	int mtyp = STATE_MSG;
+	bool xmit = false;
+	bool prb = false;
+
+	link_profile_stats(l);
+
+	switch (l->state) {
+	case LINK_ESTABLISHED:
+	case LINK_SYNCHING:
+		if (!l->silent_intv_cnt) {
+			if (tipc_bclink_acks_missing(l->owner))
+				xmit = true;
+		} else if (l->silent_intv_cnt <= l->abort_limit) {
+			xmit = true;
+			prb = true;
+		} else {
+			rc |= tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
+		}
+		l->silent_intv_cnt++;
+		break;
+	case LINK_RESET:
+		xmit = true;
+		mtyp = RESET_MSG;
+		break;
+	case LINK_ESTABLISHING:
+		xmit = true;
+		mtyp = ACTIVATE_MSG;
+		break;
+	case LINK_PEER_RESET:
+	case LINK_RESETTING:
+	case LINK_FAILINGOVER:
+		break;
+	default:
+		break;
+	}
 
-void tipc_link_delete_list(struct net *net, unsigned int bearer_id)
-{
-	struct tipc_net *tn = net_generic(net, tipc_net_id);
-	struct tipc_link *link;
-	struct tipc_node *node;
+	if (xmit)
+		tipc_link_build_proto_msg(l, mtyp, prb, 0, 0, 0, xmitq);
 
-	rcu_read_lock();
-	list_for_each_entry_rcu(node, &tn->node_list, list) {
-		tipc_node_lock(node);
-		link = node->links[bearer_id];
-		if (link)
-			tipc_link_delete(link);
-		tipc_node_unlock(node);
-	}
-	rcu_read_unlock();
+	return rc;
 }
 
 /**
@@ -334,7 +490,7 @@ void tipc_link_delete_list(struct net *net, unsigned int bearer_id)
  * @link: congested link
  * @list: message that was attempted sent
  * Create pseudo msg to send back to user when congestion abates
- * Only consumes message if there is an error
+ * Does not consume buffer list
  */
 static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
 {
@@ -347,8 +503,7 @@ static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
 	/* This really cannot happen...  */
 	if (unlikely(imp > TIPC_CRITICAL_IMPORTANCE)) {
 		pr_warn("%s<%s>, send queue full", link_rst_msg, link->name);
-		tipc_link_reset(link);
-		goto err;
+		return -ENOBUFS;
 	}
 	/* Non-blocking sender: */
 	if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
@@ -358,15 +513,12 @@ static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
 	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
 			      addr, addr, oport, 0, 0);
 	if (!skb)
-		goto err;
+		return -ENOBUFS;
 	TIPC_SKB_CB(skb)->chain_sz = skb_queue_len(list);
 	TIPC_SKB_CB(skb)->chain_imp = imp;
 	skb_queue_tail(&link->wakeupq, skb);
 	link->stats.link_congs++;
 	return -ELINKCONG;
-err:
-	__skb_queue_purge(list);
-	return -ENOBUFS;
 }
 
 /**
@@ -388,9 +540,7 @@ void link_prepare_wakeup(struct tipc_link *l)
 		if ((pnd[imp] + l->backlog[imp].len) >= lim)
 			break;
 		skb_unlink(skb, &l->wakeupq);
-		skb_queue_tail(&l->inputq, skb);
-		l->owner->inputq = &l->inputq;
-		l->owner->action_flags |= TIPC_MSG_EVT;
+		skb_queue_tail(l->inputq, skb);
 	}
 }
 
@@ -426,208 +576,36 @@ void tipc_link_purge_queues(struct tipc_link *l_ptr)
 	tipc_link_reset_fragments(l_ptr);
 }
 
-void tipc_link_reset(struct tipc_link *l_ptr)
+void tipc_link_reset(struct tipc_link *l)
 {
-	u32 prev_state = l_ptr->state;
-	int was_active_link = tipc_link_is_active(l_ptr);
-	struct tipc_node *owner = l_ptr->owner;
-	struct tipc_link *pl = tipc_parallel_link(l_ptr);
-
-	msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
+	tipc_link_fsm_evt(l, LINK_RESET_EVT);
 
 	/* Link is down, accept any session */
-	l_ptr->peer_session = INVALID_SESSION;
-
-	/* Prepare for renewed mtu size negotiation */
-	l_ptr->mtu = l_ptr->advertised_mtu;
-
-	l_ptr->state = RESET_UNKNOWN;
+	l->peer_session = WILDCARD_SESSION;
 
-	if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
-		return;
-
-	tipc_node_link_down(l_ptr->owner, l_ptr);
-	tipc_bearer_remove_dest(owner->net, l_ptr->bearer_id, l_ptr->addr);
+	/* If peer is up, it only accepts an incremented session number */
+	msg_set_session(l->pmsg, msg_session(l->pmsg) + 1);
 
-	if (was_active_link && tipc_node_is_up(l_ptr->owner) && (pl != l_ptr)) {
-		l_ptr->flags |= LINK_FAILINGOVER;
-		l_ptr->failover_checkpt = l_ptr->rcv_nxt;
-		pl->failover_pkts = FIRST_FAILOVER;
-		pl->failover_checkpt = l_ptr->rcv_nxt;
-		pl->failover_skb = l_ptr->reasm_buf;
-	} else {
-		kfree_skb(l_ptr->reasm_buf);
-	}
-	/* Clean up all queues, except inputq: */
-	__skb_queue_purge(&l_ptr->transmq);
-	__skb_queue_purge(&l_ptr->deferdq);
-	if (!owner->inputq)
-		owner->inputq = &l_ptr->inputq;
-	skb_queue_splice_init(&l_ptr->wakeupq, owner->inputq);
-	if (!skb_queue_empty(owner->inputq))
-		owner->action_flags |= TIPC_MSG_EVT;
-	tipc_link_purge_backlog(l_ptr);
-	l_ptr->reasm_buf = NULL;
-	l_ptr->rcv_unacked = 0;
-	l_ptr->snd_nxt = 1;
-	l_ptr->silent_intv_cnt = 0;
-	l_ptr->stale_count = 0;
-	link_reset_statistics(l_ptr);
-}
-
-static void link_activate(struct tipc_link *link)
-{
-	struct tipc_node *node = link->owner;
-
-	link->rcv_nxt = 1;
-	link->stats.recv_info = 1;
-	link->silent_intv_cnt = 0;
-	tipc_node_link_up(node, link);
-	tipc_bearer_add_dest(node->net, link->bearer_id, link->addr);
-}
-
-/**
- * link_state_event - link finite state machine
- * @l_ptr: pointer to link
- * @event: state machine event to process
- */
-static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
-{
-	struct tipc_link *other;
-	unsigned long timer_intv = l_ptr->keepalive_intv;
-
-	if (l_ptr->flags & LINK_STOPPED)
-		return;
-
-	if (!(l_ptr->flags & LINK_STARTED) && (event != STARTING_EVT))
-		return;		/* Not yet. */
-
-	if (l_ptr->flags & LINK_FAILINGOVER)
-		return;
-
-	switch (l_ptr->state) {
-	case WORKING_WORKING:
-		switch (event) {
-		case TRAFFIC_MSG_EVT:
-		case ACTIVATE_MSG:
-			l_ptr->silent_intv_cnt = 0;
-			break;
-		case SILENCE_EVT:
-			if (!l_ptr->silent_intv_cnt) {
-				if (tipc_bclink_acks_missing(l_ptr->owner))
-					tipc_link_proto_xmit(l_ptr, STATE_MSG,
-							     0, 0, 0, 0);
-				break;
-			}
-			l_ptr->state = WORKING_UNKNOWN;
-			tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0);
-			break;
-		case RESET_MSG:
-			pr_debug("%s<%s>, requested by peer\n",
-				 link_rst_msg, l_ptr->name);
-			tipc_link_reset(l_ptr);
-			l_ptr->state = RESET_RESET;
-			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
-					     0, 0, 0, 0);
-			break;
-		default:
-			pr_debug("%s%u in WW state\n", link_unk_evt, event);
-		}
-		break;
-	case WORKING_UNKNOWN:
-		switch (event) {
-		case TRAFFIC_MSG_EVT:
-		case ACTIVATE_MSG:
-			l_ptr->state = WORKING_WORKING;
-			l_ptr->silent_intv_cnt = 0;
-			break;
-		case RESET_MSG:
-			pr_debug("%s<%s>, requested by peer while probing\n",
-				 link_rst_msg, l_ptr->name);
-			tipc_link_reset(l_ptr);
-			l_ptr->state = RESET_RESET;
-			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
-					     0, 0, 0, 0);
-			break;
-		case SILENCE_EVT:
-			if (!l_ptr->silent_intv_cnt) {
-				l_ptr->state = WORKING_WORKING;
-				if (tipc_bclink_acks_missing(l_ptr->owner))
-					tipc_link_proto_xmit(l_ptr, STATE_MSG,
-							     0, 0, 0, 0);
-			} else if (l_ptr->silent_intv_cnt <
-				   l_ptr->abort_limit) {
-				tipc_link_proto_xmit(l_ptr, STATE_MSG,
-						     1, 0, 0, 0);
-			} else {	/* Link has failed */
-				pr_debug("%s<%s>, peer not responding\n",
-					 link_rst_msg, l_ptr->name);
-				tipc_link_reset(l_ptr);
-				l_ptr->state = RESET_UNKNOWN;
-				tipc_link_proto_xmit(l_ptr, RESET_MSG,
-						     0, 0, 0, 0);
-			}
-			break;
-		default:
-			pr_err("%s%u in WU state\n", link_unk_evt, event);
-		}
-		break;
-	case RESET_UNKNOWN:
-		switch (event) {
-		case TRAFFIC_MSG_EVT:
-			break;
-		case ACTIVATE_MSG:
-			other = l_ptr->owner->active_links[0];
-			if (other && link_working_unknown(other))
-				break;
-			l_ptr->state = WORKING_WORKING;
-			link_activate(l_ptr);
-			tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0);
-			if (l_ptr->owner->working_links == 1)
-				tipc_link_sync_xmit(l_ptr);
-			break;
-		case RESET_MSG:
-			l_ptr->state = RESET_RESET;
-			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
-					     1, 0, 0, 0);
-			break;
-		case STARTING_EVT:
-			l_ptr->flags |= LINK_STARTED;
-			link_set_timer(l_ptr, timer_intv);
-			break;
-		case SILENCE_EVT:
-			tipc_link_proto_xmit(l_ptr, RESET_MSG, 0, 0, 0, 0);
-			break;
-		default:
-			pr_err("%s%u in RU state\n", link_unk_evt, event);
-		}
-		break;
-	case RESET_RESET:
-		switch (event) {
-		case TRAFFIC_MSG_EVT:
-		case ACTIVATE_MSG:
-			other = l_ptr->owner->active_links[0];
-			if (other && link_working_unknown(other))
-				break;
-			l_ptr->state = WORKING_WORKING;
-			link_activate(l_ptr);
-			tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0);
-			if (l_ptr->owner->working_links == 1)
-				tipc_link_sync_xmit(l_ptr);
-			break;
-		case RESET_MSG:
-			break;
-		case SILENCE_EVT:
-			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
-					     0, 0, 0, 0);
-			break;
-		default:
-			pr_err("%s%u in RR state\n", link_unk_evt, event);
-		}
-		break;
-	default:
-		pr_err("Unknown link state %u/%u\n", l_ptr->state, event);
-	}
+	/* Prepare for renewed mtu size negotiation */
+	l->mtu = l->advertised_mtu;
+
+	/* Clean up all queues: */
+	__skb_queue_purge(&l->transmq);
+	__skb_queue_purge(&l->deferdq);
+	skb_queue_splice_init(&l->wakeupq, l->inputq);
+
+	tipc_link_purge_backlog(l);
+	kfree_skb(l->reasm_buf);
+	kfree_skb(l->failover_reasm_skb);
+	l->reasm_buf = NULL;
+	l->failover_reasm_skb = NULL;
+	l->rcv_unacked = 0;
+	l->snd_nxt = 1;
+	l->rcv_nxt = 1;
+	l->silent_intv_cnt = 0;
+	l->stats.recv_info = 0;
+	l->stale_count = 0;
+	link_reset_statistics(l);
 }
 
 /**
@@ -635,8 +613,7 @@ static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
  * @link: link to use
  * @list: chain of buffers containing message
  *
- * Consumes the buffer chain, except when returning -ELINKCONG,
- * since the caller then may want to make more send attempts.
+ * Consumes the buffer chain, except when returning an error code,
  * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
  * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
  */
@@ -650,7 +627,7 @@ int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 	u16 ack = mod(link->rcv_nxt - 1);
 	u16 seqno = link->snd_nxt;
 	u16 bc_last_in = link->owner->bclink.last_in;
-	struct tipc_media_addr *addr = &link->media_addr;
+	struct tipc_media_addr *addr = link->media_addr;
 	struct sk_buff_head *transmq = &link->transmq;
 	struct sk_buff_head *backlogq = &link->backlogq;
 	struct sk_buff *skb, *bskb;
@@ -660,10 +637,9 @@ int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 		if (unlikely(link->backlog[i].len >= link->backlog[i].limit))
 			return link_schedule_user(link, list);
 	}
-	if (unlikely(msg_size(msg) > mtu)) {
-		__skb_queue_purge(list);
+	if (unlikely(msg_size(msg) > mtu))
 		return -EMSGSIZE;
-	}
+
 	/* Prepare each packet for sending, and add to relevant queue: */
 	while (skb_queue_len(list)) {
 		skb = skb_peek(list);
@@ -700,101 +676,76 @@ int __tipc_link_xmit(struct net *net, struct tipc_link *link,
 	return 0;
 }
 
-static void skb2list(struct sk_buff *skb, struct sk_buff_head *list)
-{
-	skb_queue_head_init(list);
-	__skb_queue_tail(list, skb);
-}
-
-static int __tipc_link_xmit_skb(struct tipc_link *link, struct sk_buff *skb)
-{
-	struct sk_buff_head head;
-
-	skb2list(skb, &head);
-	return __tipc_link_xmit(link->owner->net, link, &head);
-}
-
-/* tipc_link_xmit_skb(): send single buffer to destination
- * Buffers sent via this functon are generally TIPC_SYSTEM_IMPORTANCE
- * messages, which will not be rejected
- * The only exception is datagram messages rerouted after secondary
- * lookup, which are rare and safe to dispose of anyway.
- * TODO: Return real return value, and let callers use
- * tipc_wait_for_sendpkt() where applicable
- */
-int tipc_link_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
-		       u32 selector)
-{
-	struct sk_buff_head head;
-	int rc;
-
-	skb2list(skb, &head);
-	rc = tipc_link_xmit(net, &head, dnode, selector);
-	if (rc == -ELINKCONG)
-		kfree_skb(skb);
-	return 0;
-}
-
 /**
- * tipc_link_xmit() is the general link level function for message sending
- * @net: the applicable net namespace
+ * tipc_link_xmit(): enqueue buffer list according to queue situation
+ * @link: link to use
  * @list: chain of buffers containing message
- * @dsz: amount of user data to be sent
- * @dnode: address of destination node
- * @selector: a number used for deterministic link selection
- * Consumes the buffer chain, except when returning -ELINKCONG
- * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
+ * @xmitq: returned list of packets to be sent by caller
+ *
+ * Consumes the buffer chain, except when returning -ELINKCONG,
+ * since the caller then may want to make more send attempts.
+ * Returns 0 if success, or errno: -ELINKCONG, -EMSGSIZE or -ENOBUFS
+ * Messages at TIPC_SYSTEM_IMPORTANCE are always accepted
  */
-int tipc_link_xmit(struct net *net, struct sk_buff_head *list, u32 dnode,
-		   u32 selector)
+int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
+		   struct sk_buff_head *xmitq)
 {
-	struct tipc_link *link = NULL;
-	struct tipc_node *node;
-	int rc = -EHOSTUNREACH;
+	struct tipc_msg *hdr = buf_msg(skb_peek(list));
+	unsigned int maxwin = l->window;
+	unsigned int i, imp = msg_importance(hdr);
+	unsigned int mtu = l->mtu;
+	u16 ack = l->rcv_nxt - 1;
+	u16 seqno = l->snd_nxt;
+	u16 bc_last_in = l->owner->bclink.last_in;
+	struct sk_buff_head *transmq = &l->transmq;
+	struct sk_buff_head *backlogq = &l->backlogq;
+	struct sk_buff *skb, *_skb, *bskb;
 
-	node = tipc_node_find(net, dnode);
-	if (node) {
-		tipc_node_lock(node);
-		link = node->active_links[selector & 1];
-		if (link)
-			rc = __tipc_link_xmit(net, link, list);
-		tipc_node_unlock(node);
-		tipc_node_put(node);
-	}
-	if (link)
-		return rc;
-
-	if (likely(in_own_node(net, dnode))) {
-		tipc_sk_rcv(net, list);
-		return 0;
+	/* Match msg importance against this and all higher backlog limits: */
+	for (i = imp; i <= TIPC_SYSTEM_IMPORTANCE; i++) {
+		if (unlikely(l->backlog[i].len >= l->backlog[i].limit))
+			return link_schedule_user(l, list);
 	}
+	if (unlikely(msg_size(hdr) > mtu))
+		return -EMSGSIZE;
 
-	__skb_queue_purge(list);
-	return rc;
-}
-
-/*
- * tipc_link_sync_xmit - synchronize broadcast link endpoints.
- *
- * Give a newly added peer node the sequence number where it should
- * start receiving and acking broadcast packets.
- *
- * Called with node locked
- */
-static void tipc_link_sync_xmit(struct tipc_link *link)
-{
-	struct sk_buff *skb;
-	struct tipc_msg *msg;
-
-	skb = tipc_buf_acquire(INT_H_SIZE);
-	if (!skb)
-		return;
+	/* Prepare each packet for sending, and add to relevant queue: */
+	while (skb_queue_len(list)) {
+		skb = skb_peek(list);
+		hdr = buf_msg(skb);
+		msg_set_seqno(hdr, seqno);
+		msg_set_ack(hdr, ack);
+		msg_set_bcast_ack(hdr, bc_last_in);
 
-	msg = buf_msg(skb);
-	tipc_msg_init(link_own_addr(link), msg, BCAST_PROTOCOL, STATE_MSG,
-		      INT_H_SIZE, link->addr);
-	msg_set_last_bcast(msg, link->owner->bclink.acked);
-	__tipc_link_xmit_skb(link, skb);
+		if (likely(skb_queue_len(transmq) < maxwin)) {
+			_skb = skb_clone(skb, GFP_ATOMIC);
+			if (!_skb)
+				return -ENOBUFS;
+			__skb_dequeue(list);
+			__skb_queue_tail(transmq, skb);
+			__skb_queue_tail(xmitq, _skb);
+			l->rcv_unacked = 0;
+			seqno++;
+			continue;
+		}
+		if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
+			kfree_skb(__skb_dequeue(list));
+			l->stats.sent_bundled++;
+			continue;
+		}
+		if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
+			kfree_skb(__skb_dequeue(list));
+			__skb_queue_tail(backlogq, bskb);
+			l->backlog[msg_importance(buf_msg(bskb))].len++;
+			l->stats.sent_bundled++;
+			l->stats.sent_bundles++;
+			continue;
+		}
+		l->backlog[imp].len += skb_queue_len(list);
+		skb_queue_splice_tail_init(list, backlogq);
+	}
+	l->snd_nxt = seqno;
+	return 0;
 }
 
 /*
@@ -842,29 +793,37 @@ void tipc_link_push_packets(struct tipc_link *link)
 		link->rcv_unacked = 0;
 		__skb_queue_tail(&link->transmq, skb);
 		tipc_bearer_send(link->owner->net, link->bearer_id,
-				 skb, &link->media_addr);
+				 skb, link->media_addr);
 	}
 	link->snd_nxt = seqno;
 }
 
-void tipc_link_reset_all(struct tipc_node *node)
+void tipc_link_advance_backlog(struct tipc_link *l, struct sk_buff_head *xmitq)
 {
-	char addr_string[16];
-	u32 i;
-
-	tipc_node_lock(node);
+	struct sk_buff *skb, *_skb;
+	struct tipc_msg *hdr;
+	u16 seqno = l->snd_nxt;
+	u16 ack = l->rcv_nxt - 1;
 
-	pr_warn("Resetting all links to %s\n",
-		tipc_addr_string_fill(addr_string, node->addr));
-
-	for (i = 0; i < MAX_BEARERS; i++) {
-		if (node->links[i]) {
-			link_print(node->links[i], "Resetting link\n");
-			tipc_link_reset(node->links[i]);
-		}
+	while (skb_queue_len(&l->transmq) < l->window) {
+		skb = skb_peek(&l->backlogq);
+		if (!skb)
+			break;
+		_skb = skb_clone(skb, GFP_ATOMIC);
+		if (!_skb)
+			break;
+		__skb_dequeue(&l->backlogq);
+		hdr = buf_msg(skb);
+		l->backlog[msg_importance(hdr)].len--;
+		__skb_queue_tail(&l->transmq, skb);
+		__skb_queue_tail(xmitq, _skb);
+		msg_set_ack(hdr, ack);
+		msg_set_seqno(hdr, seqno);
+		msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
+		l->rcv_unacked = 0;
+		seqno++;
 	}
-
-	tipc_node_unlock(node);
+	l->snd_nxt = seqno;
 }
 
 static void link_retransmit_failure(struct tipc_link *l_ptr,
@@ -877,9 +836,12 @@ static void link_retransmit_failure(struct tipc_link *l_ptr,
 
 	if (l_ptr->addr) {
 		/* Handle failure on standard link */
-		link_print(l_ptr, "Resetting link\n");
-		tipc_link_reset(l_ptr);
-
+		link_print(l_ptr, "Resetting link ");
+		pr_info("Failed msg: usr %u, typ %u, len %u, err %u\n",
+			msg_user(msg), msg_type(msg), msg_size(msg),
+			msg_errcode(msg));
+		pr_info("sqno %u, prev: %x, src: %x\n",
+			msg_seqno(msg), msg_prevnode(msg), msg_orignode(msg));
 	} else {
 		/* Handle failure on broadcast link */
 		struct tipc_node *n_ptr;
@@ -934,191 +896,45 @@ void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
 		msg_set_ack(msg, mod(l_ptr->rcv_nxt - 1));
 		msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
 		tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, skb,
-				 &l_ptr->media_addr);
+				 l_ptr->media_addr);
 		retransmits--;
 		l_ptr->stats.retransmitted++;
 	}
 }
 
-/* link_synch(): check if all packets arrived before the synch
- *               point have been consumed
- * Returns true if the parallel links are synched, otherwise false
- */
-static bool link_synch(struct tipc_link *l)
+static int tipc_link_retransm(struct tipc_link *l, int retransm,
+			      struct sk_buff_head *xmitq)
 {
-	unsigned int post_synch;
-	struct tipc_link *pl;
+	struct sk_buff *_skb, *skb = skb_peek(&l->transmq);
+	struct tipc_msg *hdr;
 
-	pl  = tipc_parallel_link(l);
-	if (pl == l)
-		goto synched;
-
-	/* Was last pre-synch packet added to input queue ? */
-	if (less_eq(pl->rcv_nxt, l->synch_point))
-		return false;
-
-	/* Is it still in the input queue ? */
-	post_synch = mod(pl->rcv_nxt - l->synch_point) - 1;
-	if (skb_queue_len(&pl->inputq) > post_synch)
-		return false;
-synched:
-	l->flags &= ~LINK_SYNCHING;
-	return true;
-}
-
-static void link_retrieve_defq(struct tipc_link *link,
-			       struct sk_buff_head *list)
-{
-	u16 seq_no;
-
-	if (skb_queue_empty(&link->deferdq))
-		return;
-
-	seq_no = buf_seqno(skb_peek(&link->deferdq));
-	if (seq_no == link->rcv_nxt)
-		skb_queue_splice_tail_init(&link->deferdq, list);
-}
-
-/**
- * tipc_rcv - process TIPC packets/messages arriving from off-node
- * @net: the applicable net namespace
- * @skb: TIPC packet
- * @b_ptr: pointer to bearer message arrived on
- *
- * Invoked with no locks held.  Bearer pointer must point to a valid bearer
- * structure (i.e. cannot be NULL), but bearer can be inactive.
- */
-void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
-{
-	struct tipc_net *tn = net_generic(net, tipc_net_id);
-	struct sk_buff_head head;
-	struct tipc_node *n_ptr;
-	struct tipc_link *l_ptr;
-	struct sk_buff *skb1, *tmp;
-	struct tipc_msg *msg;
-	u16 seq_no;
-	u16 ackd;
-	u32 released;
-
-	skb2list(skb, &head);
-
-	while ((skb = __skb_dequeue(&head))) {
-		/* Ensure message is well-formed */
-		if (unlikely(!tipc_msg_validate(skb)))
-			goto discard;
-
-		/* Handle arrival of a non-unicast link message */
-		msg = buf_msg(skb);
-		if (unlikely(msg_non_seq(msg))) {
-			if (msg_user(msg) ==  LINK_CONFIG)
-				tipc_disc_rcv(net, skb, b_ptr);
-			else
-				tipc_bclink_rcv(net, skb);
-			continue;
-		}
-
-		/* Discard unicast link messages destined for another node */
-		if (unlikely(!msg_short(msg) &&
-			     (msg_destnode(msg) != tn->own_addr)))
-			goto discard;
-
-		/* Locate neighboring node that sent message */
-		n_ptr = tipc_node_find(net, msg_prevnode(msg));
-		if (unlikely(!n_ptr))
-			goto discard;
-
-		tipc_node_lock(n_ptr);
-		/* Locate unicast link endpoint that should handle message */
-		l_ptr = n_ptr->links[b_ptr->identity];
-		if (unlikely(!l_ptr))
-			goto unlock;
-
-		/* Verify that communication with node is currently allowed */
-		if ((n_ptr->action_flags & TIPC_WAIT_PEER_LINKS_DOWN) &&
-		    msg_user(msg) == LINK_PROTOCOL &&
-		    (msg_type(msg) == RESET_MSG ||
-		    msg_type(msg) == ACTIVATE_MSG) &&
-		    !msg_redundant_link(msg))
-			n_ptr->action_flags &= ~TIPC_WAIT_PEER_LINKS_DOWN;
-
-		if (tipc_node_blocked(n_ptr))
-			goto unlock;
-
-		/* Validate message sequence number info */
-		seq_no = msg_seqno(msg);
-		ackd = msg_ack(msg);
-
-		/* Release acked messages */
-		if (unlikely(n_ptr->bclink.acked != msg_bcast_ack(msg)))
-			tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
-
-		released = 0;
-		skb_queue_walk_safe(&l_ptr->transmq, skb1, tmp) {
-			if (more(buf_seqno(skb1), ackd))
-				break;
-			 __skb_unlink(skb1, &l_ptr->transmq);
-			 kfree_skb(skb1);
-			 released = 1;
-		}
-
-		/* Try sending any messages link endpoint has pending */
-		if (unlikely(skb_queue_len(&l_ptr->backlogq)))
-			tipc_link_push_packets(l_ptr);
-
-		if (released && !skb_queue_empty(&l_ptr->wakeupq))
-			link_prepare_wakeup(l_ptr);
-
-		/* Process the incoming packet */
-		if (unlikely(!link_working_working(l_ptr))) {
-			if (msg_user(msg) == LINK_PROTOCOL) {
-				tipc_link_proto_rcv(l_ptr, skb);
-				link_retrieve_defq(l_ptr, &head);
-				skb = NULL;
-				goto unlock;
-			}
-
-			/* Traffic message. Conditionally activate link */
-			link_state_event(l_ptr, TRAFFIC_MSG_EVT);
-
-			if (link_working_working(l_ptr)) {
-				/* Re-insert buffer in front of queue */
-				__skb_queue_head(&head, skb);
-				skb = NULL;
-				goto unlock;
-			}
-			goto unlock;
-		}
-
-		/* Link is now in state WORKING_WORKING */
-		if (unlikely(seq_no != l_ptr->rcv_nxt)) {
-			link_handle_out_of_seq_msg(l_ptr, skb);
-			link_retrieve_defq(l_ptr, &head);
-			skb = NULL;
-			goto unlock;
-		}
-		l_ptr->silent_intv_cnt = 0;
+	if (!skb)
+		return 0;
 
-		/* Synchronize with parallel link if applicable */
-		if (unlikely((l_ptr->flags & LINK_SYNCHING) && !msg_dup(msg))) {
-			if (!link_synch(l_ptr))
-				goto unlock;
-		}
-		l_ptr->rcv_nxt++;
-		if (unlikely(!skb_queue_empty(&l_ptr->deferdq)))
-			link_retrieve_defq(l_ptr, &head);
-		if (unlikely(++l_ptr->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
-			l_ptr->stats.sent_acks++;
-			tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0);
-		}
-		tipc_link_input(l_ptr, skb);
-		skb = NULL;
-unlock:
-		tipc_node_unlock(n_ptr);
-		tipc_node_put(n_ptr);
-discard:
-		if (unlikely(skb))
-			kfree_skb(skb);
+	/* Detect repeated retransmit failures on same packet */
+	if (likely(l->last_retransm != buf_seqno(skb))) {
+		l->last_retransm = buf_seqno(skb);
+		l->stale_count = 1;
+	} else if (++l->stale_count > 100) {
+		link_retransmit_failure(l, skb);
+		return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
+	}
+	skb_queue_walk(&l->transmq, skb) {
+		if (!retransm)
+			return 0;
+		hdr = buf_msg(skb);
+		_skb = __pskb_copy(skb, MIN_H_SIZE, GFP_ATOMIC);
+		if (!_skb)
+			return 0;
+		hdr = buf_msg(_skb);
+		msg_set_ack(hdr, l->rcv_nxt - 1);
+		msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
+		_skb->priority = TC_PRIO_CONTROL;
+		__skb_queue_tail(xmitq, _skb);
+		retransm--;
+		l->stats.retransmitted++;
 	}
+	return 0;
 }
 
 /* tipc_data_input - deliver data and name distr msgs to upper layer
@@ -1126,29 +942,22 @@ discard:
  * Consumes buffer if message is of right type
  * Node lock must be held
  */
-static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
+static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb,
+			    struct sk_buff_head *inputq)
 {
 	struct tipc_node *node = link->owner;
-	struct tipc_msg *msg = buf_msg(skb);
-	u32 dport = msg_destport(msg);
 
-	switch (msg_user(msg)) {
+	switch (msg_user(buf_msg(skb))) {
 	case TIPC_LOW_IMPORTANCE:
 	case TIPC_MEDIUM_IMPORTANCE:
 	case TIPC_HIGH_IMPORTANCE:
 	case TIPC_CRITICAL_IMPORTANCE:
 	case CONN_MANAGER:
-		if (tipc_skb_queue_tail(&link->inputq, skb, dport)) {
-			node->inputq = &link->inputq;
-			node->action_flags |= TIPC_MSG_EVT;
-		}
+		__skb_queue_tail(inputq, skb);
 		return true;
 	case NAME_DISTRIBUTOR:
 		node->bclink.recv_permitted = true;
-		node->namedq = &link->namedq;
-		skb_queue_tail(&link->namedq, skb);
-		if (skb_queue_len(&link->namedq) == 1)
-			node->action_flags |= TIPC_NAMED_MSG_EVT;
+		skb_queue_tail(link->namedq, skb);
 		return true;
 	case MSG_BUNDLER:
 	case TUNNEL_PROTOCOL:
@@ -1165,54 +974,160 @@ static bool tipc_data_input(struct tipc_link *link, struct sk_buff *skb)
 /* tipc_link_input - process packet that has passed link protocol check
  *
  * Consumes buffer
- * Node lock must be held
  */
-static void tipc_link_input(struct tipc_link *link, struct sk_buff *skb)
+static int tipc_link_input(struct tipc_link *l, struct sk_buff *skb,
+			   struct sk_buff_head *inputq)
 {
-	struct tipc_node *node = link->owner;
-	struct tipc_msg *msg = buf_msg(skb);
+	struct tipc_node *node = l->owner;
+	struct tipc_msg *hdr = buf_msg(skb);
+	struct sk_buff **reasm_skb = &l->reasm_buf;
 	struct sk_buff *iskb;
+	int usr = msg_user(hdr);
+	int rc = 0;
 	int pos = 0;
+	int ipos = 0;
 
-	if (likely(tipc_data_input(link, skb)))
-		return;
+	if (unlikely(usr == TUNNEL_PROTOCOL)) {
+		if (msg_type(hdr) == SYNCH_MSG) {
+			__skb_queue_purge(&l->deferdq);
+			goto drop;
+		}
+		if (!tipc_msg_extract(skb, &iskb, &ipos))
+			return rc;
+		kfree_skb(skb);
+		skb = iskb;
+		hdr = buf_msg(skb);
+		if (less(msg_seqno(hdr), l->drop_point))
+			goto drop;
+		if (tipc_data_input(l, skb, inputq))
+			return rc;
+		usr = msg_user(hdr);
+		reasm_skb = &l->failover_reasm_skb;
+	}
 
-	switch (msg_user(msg)) {
-	case TUNNEL_PROTOCOL:
-		if (msg_dup(msg)) {
-			link->flags |= LINK_SYNCHING;
-			link->synch_point = msg_seqno(msg_get_wrapped(msg));
-			kfree_skb(skb);
-			break;
+	if (usr == MSG_BUNDLER) {
+		l->stats.recv_bundles++;
+		l->stats.recv_bundled += msg_msgcnt(hdr);
+		while (tipc_msg_extract(skb, &iskb, &pos))
+			tipc_data_input(l, iskb, inputq);
+		return 0;
+	} else if (usr == MSG_FRAGMENTER) {
+		l->stats.recv_fragments++;
+		if (tipc_buf_append(reasm_skb, &skb)) {
+			l->stats.recv_fragmented++;
+			tipc_data_input(l, skb, inputq);
+		} else if (!*reasm_skb) {
+			return tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 		}
-		if (!tipc_link_failover_rcv(link, &skb))
-			break;
-		if (msg_user(buf_msg(skb)) != MSG_BUNDLER) {
-			tipc_data_input(link, skb);
+		return 0;
+	} else if (usr == BCAST_PROTOCOL) {
+		tipc_link_sync_rcv(node, skb);
+		return 0;
+	}
+drop:
+	kfree_skb(skb);
+	return 0;
+}
+
+static bool tipc_link_release_pkts(struct tipc_link *l, u16 acked)
+{
+	bool released = false;
+	struct sk_buff *skb, *tmp;
+
+	skb_queue_walk_safe(&l->transmq, skb, tmp) {
+		if (more(buf_seqno(skb), acked))
 			break;
+		__skb_unlink(skb, &l->transmq);
+		kfree_skb(skb);
+		released = true;
+	}
+	return released;
+}
+
+/* tipc_link_rcv - process TIPC packets/messages arriving from off-node
+ * @link: the link that should handle the message
+ * @skb: TIPC packet
+ * @xmitq: queue to place packets to be sent after this call
+ */
+int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
+		  struct sk_buff_head *xmitq)
+{
+	struct sk_buff_head *arrvq = &l->deferdq;
+	struct sk_buff_head tmpq;
+	struct tipc_msg *hdr;
+	u16 seqno, rcv_nxt;
+	int rc = 0;
+
+	__skb_queue_head_init(&tmpq);
+
+	if (unlikely(!__tipc_skb_queue_sorted(arrvq, skb))) {
+		if (!(skb_queue_len(arrvq) % TIPC_NACK_INTV))
+			tipc_link_build_proto_msg(l, STATE_MSG, 0,
+						  0, 0, 0, xmitq);
+		return rc;
+	}
+
+	while ((skb = skb_peek(arrvq))) {
+		hdr = buf_msg(skb);
+
+		/* Verify and update link state */
+		if (unlikely(msg_user(hdr) == LINK_PROTOCOL)) {
+			__skb_dequeue(arrvq);
+			rc = tipc_link_proto_rcv(l, skb, xmitq);
+			continue;
 		}
-	case MSG_BUNDLER:
-		link->stats.recv_bundles++;
-		link->stats.recv_bundled += msg_msgcnt(msg);
 
-		while (tipc_msg_extract(skb, &iskb, &pos))
-			tipc_data_input(link, iskb);
-		break;
-	case MSG_FRAGMENTER:
-		link->stats.recv_fragments++;
-		if (tipc_buf_append(&link->reasm_buf, &skb)) {
-			link->stats.recv_fragmented++;
-			tipc_data_input(link, skb);
-		} else if (!link->reasm_buf) {
-			tipc_link_reset(link);
+		if (unlikely(!link_is_up(l))) {
+			rc = tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
+			if (!link_is_up(l)) {
+				kfree_skb(__skb_dequeue(arrvq));
+				goto exit;
+			}
 		}
-		break;
-	case BCAST_PROTOCOL:
-		tipc_link_sync_rcv(node, skb);
-		break;
-	default:
-		break;
-	};
+
+		l->silent_intv_cnt = 0;
+
+		/* Forward queues and wake up waiting users */
+		if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
+			tipc_link_advance_backlog(l, xmitq);
+			if (unlikely(!skb_queue_empty(&l->wakeupq)))
+				link_prepare_wakeup(l);
+		}
+
+		/* Defer reception if there is a gap in the sequence */
+		seqno = msg_seqno(hdr);
+		rcv_nxt = l->rcv_nxt;
+		if (unlikely(less(rcv_nxt, seqno))) {
+			l->stats.deferred_recv++;
+			goto exit;
+		}
+
+		__skb_dequeue(arrvq);
+
+		/* Drop if packet already received */
+		if (unlikely(more(rcv_nxt, seqno))) {
+			l->stats.duplicates++;
+			kfree_skb(skb);
+			goto exit;
+		}
+
+		/* Packet can be delivered */
+		l->rcv_nxt++;
+		l->stats.recv_info++;
+		if (unlikely(!tipc_data_input(l, skb, &tmpq)))
+			rc = tipc_link_input(l, skb, &tmpq);
+
+		/* Ack at regular intervals */
+		if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN)) {
+			l->rcv_unacked = 0;
+			l->stats.sent_acks++;
+			tipc_link_build_proto_msg(l, STATE_MSG,
+						  0, 0, 0, 0, xmitq);
+		}
+	}
+exit:
+	tipc_skb_queue_splice_tail(&tmpq, l->inputq);
+	return rc;
 }
 
 /**
@@ -1255,458 +1170,250 @@ u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
 }
 
 /*
- * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
+ * Send protocol message to the other endpoint.
  */
-static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
-				       struct sk_buff *buf)
+void tipc_link_proto_xmit(struct tipc_link *l, u32 msg_typ, int probe_msg,
+			  u32 gap, u32 tolerance, u32 priority)
 {
-	u32 seq_no = buf_seqno(buf);
+	struct sk_buff *skb = NULL;
+	struct sk_buff_head xmitq;
 
-	if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
-		tipc_link_proto_rcv(l_ptr, buf);
+	__skb_queue_head_init(&xmitq);
+	tipc_link_build_proto_msg(l, msg_typ, probe_msg, gap,
+				  tolerance, priority, &xmitq);
+	skb = __skb_dequeue(&xmitq);
+	if (!skb)
 		return;
-	}
-
-	/* Record OOS packet arrival */
-	l_ptr->silent_intv_cnt = 0;
+	tipc_bearer_send(l->owner->net, l->bearer_id, skb, l->media_addr);
+	l->rcv_unacked = 0;
+	kfree_skb(skb);
+}
 
-	/*
-	 * Discard packet if a duplicate; otherwise add it to deferred queue
-	 * and notify peer of gap as per protocol specification
-	 */
-	if (less(seq_no, l_ptr->rcv_nxt)) {
-		l_ptr->stats.duplicates++;
-		kfree_skb(buf);
+/* tipc_link_build_proto_msg: prepare link protocol message for transmission
+ */
+static void tipc_link_build_proto_msg(struct tipc_link *l, int mtyp, bool probe,
+				      u16 rcvgap, int tolerance, int priority,
+				      struct sk_buff_head *xmitq)
+{
+	struct sk_buff *skb = NULL;
+	struct tipc_msg *hdr = l->pmsg;
+	u16 snd_nxt = l->snd_nxt;
+	u16 rcv_nxt = l->rcv_nxt;
+	u16 rcv_last = rcv_nxt - 1;
+	int node_up = l->owner->bclink.recv_permitted;
+
+	/* Don't send protocol message during reset or link failover */
+	if (tipc_link_is_blocked(l))
 		return;
-	}
 
-	if (tipc_link_defer_pkt(&l_ptr->deferdq, buf)) {
-		l_ptr->stats.deferred_recv++;
-		if ((skb_queue_len(&l_ptr->deferdq) % TIPC_MIN_LINK_WIN) == 1)
-			tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0);
+	msg_set_type(hdr, mtyp);
+	msg_set_net_plane(hdr, l->net_plane);
+	msg_set_bcast_ack(hdr, l->owner->bclink.last_in);
+	msg_set_last_bcast(hdr, tipc_bclink_get_last_sent(l->owner->net));
+	msg_set_link_tolerance(hdr, tolerance);
+	msg_set_linkprio(hdr, priority);
+	msg_set_redundant_link(hdr, node_up);
+	msg_set_seq_gap(hdr, 0);
+
+	/* Compatibility: created msg must not be in sequence with pkt flow */
+	msg_set_seqno(hdr, snd_nxt + U16_MAX / 2);
+
+	if (mtyp == STATE_MSG) {
+		if (!tipc_link_is_up(l))
+			return;
+		msg_set_next_sent(hdr, snd_nxt);
+
+		/* Override rcvgap if there are packets in deferred queue */
+		if (!skb_queue_empty(&l->deferdq))
+			rcvgap = buf_seqno(skb_peek(&l->deferdq)) - rcv_nxt;
+		if (rcvgap) {
+			msg_set_seq_gap(hdr, rcvgap);
+			l->stats.sent_nacks++;
+		}
+		msg_set_ack(hdr, rcv_last);
+		msg_set_probe(hdr, probe);
+		if (probe)
+			l->stats.sent_probes++;
+		l->stats.sent_states++;
 	} else {
-		l_ptr->stats.duplicates++;
+		/* RESET_MSG or ACTIVATE_MSG */
+		msg_set_max_pkt(hdr, l->advertised_mtu);
+		msg_set_ack(hdr, l->rcv_nxt - 1);
+		msg_set_next_sent(hdr, 1);
 	}
+	skb = tipc_buf_acquire(msg_size(hdr));
+	if (!skb)
+		return;
+	skb_copy_to_linear_data(skb, hdr, msg_size(hdr));
+	skb->priority = TC_PRIO_CONTROL;
+	__skb_queue_tail(xmitq, skb);
 }
 
-/*
- * Send protocol message to the other endpoint.
+/* tipc_link_tnl_prepare(): prepare and return a list of tunnel packets
+ * with contents of the link's tranmsit and backlog queues.
  */
-void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int probe_msg,
-			  u32 gap, u32 tolerance, u32 priority)
+void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
+			   int mtyp, struct sk_buff_head *xmitq)
 {
-	struct sk_buff *buf = NULL;
-	struct tipc_msg *msg = l_ptr->pmsg;
-	u32 msg_size = sizeof(l_ptr->proto_msg);
-	int r_flag;
-	u16 last_rcv;
-
-	/* Don't send protocol message during link failover */
-	if (l_ptr->flags & LINK_FAILINGOVER)
-		return;
+	struct sk_buff *skb, *tnlskb;
+	struct tipc_msg *hdr, tnlhdr;
+	struct sk_buff_head *queue = &l->transmq;
+	struct sk_buff_head tmpxq, tnlq;
+	u16 pktlen, pktcnt, seqno = l->snd_nxt;
 
-	/* Abort non-RESET send if communication with node is prohibited */
-	if ((tipc_node_blocked(l_ptr->owner)) && (msg_typ != RESET_MSG))
+	if (!tnl)
 		return;
 
-	/* Create protocol message with "out-of-sequence" sequence number */
-	msg_set_type(msg, msg_typ);
-	msg_set_net_plane(msg, l_ptr->net_plane);
-	msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
-	msg_set_last_bcast(msg, tipc_bclink_get_last_sent(l_ptr->owner->net));
-
-	if (msg_typ == STATE_MSG) {
-		u16 next_sent = l_ptr->snd_nxt;
+	skb_queue_head_init(&tnlq);
+	skb_queue_head_init(&tmpxq);
 
-		if (!tipc_link_is_up(l_ptr))
+	/* At least one packet required for safe algorithm => add dummy */
+	skb = tipc_msg_create(TIPC_LOW_IMPORTANCE, TIPC_DIRECT_MSG,
+			      BASIC_H_SIZE, 0, l->addr, link_own_addr(l),
+			      0, 0, TIPC_ERR_NO_PORT);
+	if (!skb) {
+		pr_warn("%sunable to create tunnel packet\n", link_co_err);
+		return;
+	}
+	skb_queue_tail(&tnlq, skb);
+	tipc_link_xmit(l, &tnlq, &tmpxq);
+	__skb_queue_purge(&tmpxq);
+
+	/* Initialize reusable tunnel packet header */
+	tipc_msg_init(link_own_addr(l), &tnlhdr, TUNNEL_PROTOCOL,
+		      mtyp, INT_H_SIZE, l->addr);
+	pktcnt = skb_queue_len(&l->transmq) + skb_queue_len(&l->backlogq);
+	msg_set_msgcnt(&tnlhdr, pktcnt);
+	msg_set_bearer_id(&tnlhdr, l->peer_bearer_id);
+tnl:
+	/* Wrap each packet into a tunnel packet */
+	skb_queue_walk(queue, skb) {
+		hdr = buf_msg(skb);
+		if (queue == &l->backlogq)
+			msg_set_seqno(hdr, seqno++);
+		pktlen = msg_size(hdr);
+		msg_set_size(&tnlhdr, pktlen + INT_H_SIZE);
+		tnlskb = tipc_buf_acquire(pktlen + INT_H_SIZE);
+		if (!tnlskb) {
+			pr_warn("%sunable to send packet\n", link_co_err);
 			return;
-		msg_set_next_sent(msg, next_sent);
-		if (!skb_queue_empty(&l_ptr->deferdq)) {
-			last_rcv = buf_seqno(skb_peek(&l_ptr->deferdq));
-			gap = mod(last_rcv - l_ptr->rcv_nxt);
 		}
-		msg_set_seq_gap(msg, gap);
-		if (gap)
-			l_ptr->stats.sent_nacks++;
-		msg_set_link_tolerance(msg, tolerance);
-		msg_set_linkprio(msg, priority);
-		msg_set_max_pkt(msg, l_ptr->mtu);
-		msg_set_ack(msg, mod(l_ptr->rcv_nxt - 1));
-		msg_set_probe(msg, probe_msg != 0);
-		if (probe_msg)
-			l_ptr->stats.sent_probes++;
-		l_ptr->stats.sent_states++;
-	} else {		/* RESET_MSG or ACTIVATE_MSG */
-		msg_set_ack(msg, mod(l_ptr->failover_checkpt - 1));
-		msg_set_seq_gap(msg, 0);
-		msg_set_next_sent(msg, 1);
-		msg_set_probe(msg, 0);
-		msg_set_link_tolerance(msg, l_ptr->tolerance);
-		msg_set_linkprio(msg, l_ptr->priority);
-		msg_set_max_pkt(msg, l_ptr->advertised_mtu);
+		skb_copy_to_linear_data(tnlskb, &tnlhdr, INT_H_SIZE);
+		skb_copy_to_linear_data_offset(tnlskb, INT_H_SIZE, hdr, pktlen);
+		__skb_queue_tail(&tnlq, tnlskb);
+	}
+	if (queue != &l->backlogq) {
+		queue = &l->backlogq;
+		goto tnl;
 	}
 
-	r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
-	msg_set_redundant_link(msg, r_flag);
-	msg_set_linkprio(msg, l_ptr->priority);
-	msg_set_size(msg, msg_size);
-
-	msg_set_seqno(msg, mod(l_ptr->snd_nxt + (0xffff / 2)));
-
-	buf = tipc_buf_acquire(msg_size);
-	if (!buf)
-		return;
+	tipc_link_xmit(tnl, &tnlq, xmitq);
 
-	skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
-	buf->priority = TC_PRIO_CONTROL;
-	tipc_bearer_send(l_ptr->owner->net, l_ptr->bearer_id, buf,
-			 &l_ptr->media_addr);
-	l_ptr->rcv_unacked = 0;
-	kfree_skb(buf);
+	if (mtyp == FAILOVER_MSG) {
+		tnl->drop_point = l->rcv_nxt;
+		tnl->failover_reasm_skb = l->reasm_buf;
+		l->reasm_buf = NULL;
+	}
 }
 
-/*
- * Receive protocol message :
+/* tipc_link_proto_rcv(): receive link level protocol message :
  * Note that network plane id propagates through the network, and may
- * change at any time. The node with lowest address rules
+ * change at any time. The node with lowest numerical id determines
+ * network plane
  */
-static void tipc_link_proto_rcv(struct tipc_link *l_ptr,
-				struct sk_buff *buf)
+static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
+			       struct sk_buff_head *xmitq)
 {
-	u32 rec_gap = 0;
-	u32 msg_tol;
-	struct tipc_msg *msg = buf_msg(buf);
+	struct tipc_msg *hdr = buf_msg(skb);
+	u16 rcvgap = 0;
+	u16 nacked_gap = msg_seq_gap(hdr);
+	u16 peers_snd_nxt =  msg_next_sent(hdr);
+	u16 peers_tol = msg_link_tolerance(hdr);
+	u16 peers_prio = msg_linkprio(hdr);
+	u16 rcv_nxt = l->rcv_nxt;
+	char *if_name;
+	int rc = 0;
 
-	if (l_ptr->flags & LINK_FAILINGOVER)
+	if (tipc_link_is_blocked(l))
 		goto exit;
 
-	if (l_ptr->net_plane != msg_net_plane(msg))
-		if (link_own_addr(l_ptr) > msg_prevnode(msg))
-			l_ptr->net_plane = msg_net_plane(msg);
-
-	switch (msg_type(msg)) {
+	if (link_own_addr(l) > msg_prevnode(hdr))
+		l->net_plane = msg_net_plane(hdr);
 
+	switch (msg_type(hdr)) {
 	case RESET_MSG:
-		if (!link_working_unknown(l_ptr) &&
-		    (l_ptr->peer_session != INVALID_SESSION)) {
-			if (less_eq(msg_session(msg), l_ptr->peer_session))
-				break; /* duplicate or old reset: ignore */
-		}
-
-		if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
-				link_working_unknown(l_ptr))) {
-			/*
-			 * peer has lost contact -- don't allow peer's links
-			 * to reactivate before we recognize loss & clean up
-			 */
-			l_ptr->owner->action_flags |= TIPC_WAIT_OWN_LINKS_DOWN;
-		}
-
-		link_state_event(l_ptr, RESET_MSG);
 
+		/* Ignore duplicate RESET with old session number */
+		if ((less_eq(msg_session(hdr), l->peer_session)) &&
+		    (l->peer_session != WILDCARD_SESSION))
+			break;
 		/* fall thru' */
-	case ACTIVATE_MSG:
-		/* Update link settings according other endpoint's values */
-		strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
 
-		msg_tol = msg_link_tolerance(msg);
-		if (msg_tol > l_ptr->tolerance)
-			link_set_supervision_props(l_ptr, msg_tol);
-
-		if (msg_linkprio(msg) > l_ptr->priority)
-			l_ptr->priority = msg_linkprio(msg);
-
-		if (l_ptr->mtu > msg_max_pkt(msg))
-			l_ptr->mtu = msg_max_pkt(msg);
-
-		/* Synchronize broadcast link info, if not done previously */
-		if (!tipc_node_is_up(l_ptr->owner)) {
-			l_ptr->owner->bclink.last_sent =
-				l_ptr->owner->bclink.last_in =
-				msg_last_bcast(msg);
-			l_ptr->owner->bclink.oos_state = 0;
-		}
-
-		l_ptr->peer_session = msg_session(msg);
-		l_ptr->peer_bearer_id = msg_bearer_id(msg);
-
-		if (msg_type(msg) == ACTIVATE_MSG)
-			link_state_event(l_ptr, ACTIVATE_MSG);
-		break;
-	case STATE_MSG:
+	case ACTIVATE_MSG:
 
-		msg_tol = msg_link_tolerance(msg);
-		if (msg_tol)
-			link_set_supervision_props(l_ptr, msg_tol);
-
-		if (msg_linkprio(msg) &&
-		    (msg_linkprio(msg) != l_ptr->priority)) {
-			pr_debug("%s<%s>, priority change %u->%u\n",
-				 link_rst_msg, l_ptr->name,
-				 l_ptr->priority, msg_linkprio(msg));
-			l_ptr->priority = msg_linkprio(msg);
-			tipc_link_reset(l_ptr); /* Enforce change to take effect */
+		/* Complete own link name with peer's interface name */
+		if_name =  strrchr(l->name, ':') + 1;
+		if (sizeof(l->name) - (if_name - l->name) <= TIPC_MAX_IF_NAME)
 			break;
-		}
-
-		/* Record reception; force mismatch at next timeout: */
-		l_ptr->silent_intv_cnt = 0;
-
-		link_state_event(l_ptr, TRAFFIC_MSG_EVT);
-		l_ptr->stats.recv_states++;
-		if (link_reset_unknown(l_ptr))
+		if (msg_data_sz(hdr) < TIPC_MAX_IF_NAME)
 			break;
+		strncpy(if_name, msg_data(hdr),	TIPC_MAX_IF_NAME);
 
-		if (less_eq(l_ptr->rcv_nxt, msg_next_sent(msg)))
-			rec_gap = mod(msg_next_sent(msg) - l_ptr->rcv_nxt);
+		/* Update own tolerance if peer indicates a non-zero value */
+		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
+			l->tolerance = peers_tol;
 
-		if (msg_probe(msg))
-			l_ptr->stats.recv_probes++;
+		/* Update own priority if peer's priority is higher */
+		if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
+			l->priority = peers_prio;
 
-		/* Protocol message before retransmits, reduce loss risk */
-		if (l_ptr->owner->bclink.recv_permitted)
-			tipc_bclink_update_link_state(l_ptr->owner,
-						      msg_last_bcast(msg));
-
-		if (rec_gap || (msg_probe(msg))) {
-			tipc_link_proto_xmit(l_ptr, STATE_MSG, 0,
-					     rec_gap, 0, 0);
-		}
-		if (msg_seq_gap(msg)) {
-			l_ptr->stats.recv_nacks++;
-			tipc_link_retransmit(l_ptr, skb_peek(&l_ptr->transmq),
-					     msg_seq_gap(msg));
+		if (msg_type(hdr) == RESET_MSG) {
+			rc |= tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
+		} else if (!link_is_up(l)) {
+			tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
+			rc |= tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
 		}
+		l->peer_session = msg_session(hdr);
+		l->peer_bearer_id = msg_bearer_id(hdr);
+		if (l->mtu > msg_max_pkt(hdr))
+			l->mtu = msg_max_pkt(hdr);
 		break;
-	}
-exit:
-	kfree_skb(buf);
-}
-
-
-/* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
- * a different bearer. Owner node is locked.
- */
-static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
-				  struct tipc_msg *tunnel_hdr,
-				  struct tipc_msg *msg,
-				  u32 selector)
-{
-	struct tipc_link *tunnel;
-	struct sk_buff *skb;
-	u32 length = msg_size(msg);
-
-	tunnel = l_ptr->owner->active_links[selector & 1];
-	if (!tipc_link_is_up(tunnel)) {
-		pr_warn("%stunnel link no longer available\n", link_co_err);
-		return;
-	}
-	msg_set_size(tunnel_hdr, length + INT_H_SIZE);
-	skb = tipc_buf_acquire(length + INT_H_SIZE);
-	if (!skb) {
-		pr_warn("%sunable to send tunnel msg\n", link_co_err);
-		return;
-	}
-	skb_copy_to_linear_data(skb, tunnel_hdr, INT_H_SIZE);
-	skb_copy_to_linear_data_offset(skb, INT_H_SIZE, msg, length);
-	__tipc_link_xmit_skb(tunnel, skb);
-}
-
-
-/* tipc_link_failover_send_queue(): A link has gone down, but a second
- * link is still active. We can do failover. Tunnel the failing link's
- * whole send queue via the remaining link. This way, we don't lose
- * any packets, and sequence order is preserved for subsequent traffic
- * sent over the remaining link. Owner node is locked.
- */
-void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
-{
-	int msgcount;
-	struct tipc_link *tunnel = l_ptr->owner->active_links[0];
-	struct tipc_msg tunnel_hdr;
-	struct sk_buff *skb;
-	int split_bundles;
-
-	if (!tunnel)
-		return;
 
-	tipc_msg_init(link_own_addr(l_ptr), &tunnel_hdr, TUNNEL_PROTOCOL,
-		      FAILOVER_MSG, INT_H_SIZE, l_ptr->addr);
-
-	skb_queue_walk(&l_ptr->backlogq, skb) {
-		msg_set_seqno(buf_msg(skb), l_ptr->snd_nxt);
-		l_ptr->snd_nxt = mod(l_ptr->snd_nxt + 1);
-	}
-	skb_queue_splice_tail_init(&l_ptr->backlogq, &l_ptr->transmq);
-	tipc_link_purge_backlog(l_ptr);
-	msgcount = skb_queue_len(&l_ptr->transmq);
-	msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
-	msg_set_msgcnt(&tunnel_hdr, msgcount);
-
-	if (skb_queue_empty(&l_ptr->transmq)) {
-		skb = tipc_buf_acquire(INT_H_SIZE);
-		if (skb) {
-			skb_copy_to_linear_data(skb, &tunnel_hdr, INT_H_SIZE);
-			msg_set_size(&tunnel_hdr, INT_H_SIZE);
-			__tipc_link_xmit_skb(tunnel, skb);
-		} else {
-			pr_warn("%sunable to send changeover msg\n",
-				link_co_err);
-		}
-		return;
-	}
-
-	split_bundles = (l_ptr->owner->active_links[0] !=
-			 l_ptr->owner->active_links[1]);
+	case STATE_MSG:
 
-	skb_queue_walk(&l_ptr->transmq, skb) {
-		struct tipc_msg *msg = buf_msg(skb);
+		/* Update own tolerance if peer indicates a non-zero value */
+		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL))
+			l->tolerance = peers_tol;
 
-		if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
-			struct tipc_msg *m = msg_get_wrapped(msg);
-			unchar *pos = (unchar *)m;
+		l->silent_intv_cnt = 0;
+		l->stats.recv_states++;
+		if (msg_probe(hdr))
+			l->stats.recv_probes++;
+		rc = tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
+		if (!link_is_up(l))
+			break;
 
-			msgcount = msg_msgcnt(msg);
-			while (msgcount--) {
-				msg_set_seqno(m, msg_seqno(msg));
-				tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
-						      msg_link_selector(m));
-				pos += align(msg_size(m));
-				m = (struct tipc_msg *)pos;
-			}
-		} else {
-			tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
-					      msg_link_selector(msg));
+		/* Send NACK if peer has sent pkts we haven't received yet */
+		if (more(peers_snd_nxt, rcv_nxt) && !tipc_link_is_synching(l))
+			rcvgap = peers_snd_nxt - l->rcv_nxt;
+		if (rcvgap || (msg_probe(hdr)))
+			tipc_link_build_proto_msg(l, STATE_MSG, 0, rcvgap,
+						  0, 0, xmitq);
+		tipc_link_release_pkts(l, msg_ack(hdr));
+
+		/* If NACK, retransmit will now start at right position */
+		if (nacked_gap) {
+			rc = tipc_link_retransm(l, nacked_gap, xmitq);
+			l->stats.recv_nacks++;
 		}
-	}
-}
-
-/* tipc_link_dup_queue_xmit(): A second link has become active. Tunnel a
- * duplicate of the first link's send queue via the new link. This way, we
- * are guaranteed that currently queued packets from a socket are delivered
- * before future traffic from the same socket, even if this is using the
- * new link. The last arriving copy of each duplicate packet is dropped at
- * the receiving end by the regular protocol check, so packet cardinality
- * and sequence order is preserved per sender/receiver socket pair.
- * Owner node is locked.
- */
-void tipc_link_dup_queue_xmit(struct tipc_link *link,
-			      struct tipc_link *tnl)
-{
-	struct sk_buff *skb;
-	struct tipc_msg tnl_hdr;
-	struct sk_buff_head *queue = &link->transmq;
-	int mcnt;
-	u16 seqno;
-
-	tipc_msg_init(link_own_addr(link), &tnl_hdr, TUNNEL_PROTOCOL,
-		      SYNCH_MSG, INT_H_SIZE, link->addr);
-	mcnt = skb_queue_len(&link->transmq) + skb_queue_len(&link->backlogq);
-	msg_set_msgcnt(&tnl_hdr, mcnt);
-	msg_set_bearer_id(&tnl_hdr, link->peer_bearer_id);
-
-tunnel_queue:
-	skb_queue_walk(queue, skb) {
-		struct sk_buff *outskb;
-		struct tipc_msg *msg = buf_msg(skb);
-		u32 len = msg_size(msg);
 
-		msg_set_ack(msg, mod(link->rcv_nxt - 1));
-		msg_set_bcast_ack(msg, link->owner->bclink.last_in);
-		msg_set_size(&tnl_hdr, len + INT_H_SIZE);
-		outskb = tipc_buf_acquire(len + INT_H_SIZE);
-		if (outskb == NULL) {
-			pr_warn("%sunable to send duplicate msg\n",
-				link_co_err);
-			return;
-		}
-		skb_copy_to_linear_data(outskb, &tnl_hdr, INT_H_SIZE);
-		skb_copy_to_linear_data_offset(outskb, INT_H_SIZE,
-					       skb->data, len);
-		__tipc_link_xmit_skb(tnl, outskb);
-		if (!tipc_link_is_up(link))
-			return;
-	}
-	if (queue == &link->backlogq)
-		return;
-	seqno = link->snd_nxt;
-	skb_queue_walk(&link->backlogq, skb) {
-		msg_set_seqno(buf_msg(skb), seqno);
-		seqno = mod(seqno + 1);
-	}
-	queue = &link->backlogq;
-	goto tunnel_queue;
-}
-
-/*  tipc_link_failover_rcv(): Receive a tunnelled FAILOVER_MSG packet
- *  Owner node is locked.
- */
-static bool tipc_link_failover_rcv(struct tipc_link *link,
-				   struct sk_buff **skb)
-{
-	struct tipc_msg *msg = buf_msg(*skb);
-	struct sk_buff *iskb = NULL;
-	struct tipc_link *pl = NULL;
-	int bearer_id = msg_bearer_id(msg);
-	int pos = 0;
-
-	if (msg_type(msg) != FAILOVER_MSG) {
-		pr_warn("%sunknown tunnel pkt received\n", link_co_err);
-		goto exit;
-	}
-	if (bearer_id >= MAX_BEARERS)
-		goto exit;
-
-	if (bearer_id == link->bearer_id)
-		goto exit;
-
-	pl = link->owner->links[bearer_id];
-	if (pl && tipc_link_is_up(pl))
-		tipc_link_reset(pl);
-
-	if (link->failover_pkts == FIRST_FAILOVER)
-		link->failover_pkts = msg_msgcnt(msg);
-
-	/* Should we expect an inner packet? */
-	if (!link->failover_pkts)
-		goto exit;
-
-	if (!tipc_msg_extract(*skb, &iskb, &pos)) {
-		pr_warn("%sno inner failover pkt\n", link_co_err);
-		*skb = NULL;
-		goto exit;
-	}
-	link->failover_pkts--;
-	*skb = NULL;
-
-	/* Was this packet already delivered? */
-	if (less(buf_seqno(iskb), link->failover_checkpt)) {
-		kfree_skb(iskb);
-		iskb = NULL;
-		goto exit;
-	}
-	if (msg_user(buf_msg(iskb)) == MSG_FRAGMENTER) {
-		link->stats.recv_fragments++;
-		tipc_buf_append(&link->failover_skb, &iskb);
+		tipc_link_advance_backlog(l, xmitq);
+		if (unlikely(!skb_queue_empty(&l->wakeupq)))
+			link_prepare_wakeup(l);
 	}
 exit:
-	if (!link->failover_pkts && pl)
-		pl->flags &= ~LINK_FAILINGOVER;
-	kfree_skb(*skb);
-	*skb = iskb;
-	return *skb;
-}
-
-static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tol)
-{
-	unsigned long intv = ((tol / 4) > 500) ? 500 : tol / 4;
-
-	if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
-		return;
-
-	l_ptr->tolerance = tol;
-	l_ptr->keepalive_intv = msecs_to_jiffies(intv);
-	l_ptr->abort_limit = tol / (jiffies_to_msecs(l_ptr->keepalive_intv));
+	kfree_skb(skb);
+	return rc;
 }
 
 void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
@@ -1743,7 +1450,7 @@ static struct tipc_node *tipc_link_find_owner(struct net *net,
 	list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
 		tipc_node_lock(n_ptr);
 		for (i = 0; i < MAX_BEARERS; i++) {
-			l_ptr = n_ptr->links[i];
+			l_ptr = n_ptr->links[i].link;
 			if (l_ptr && !strcmp(l_ptr->name, link_name)) {
 				*bearer_id = i;
 				found_node = n_ptr;
@@ -1770,27 +1477,16 @@ static void link_reset_statistics(struct tipc_link *l_ptr)
 	l_ptr->stats.recv_info = l_ptr->rcv_nxt;
 }
 
-static void link_print(struct tipc_link *l_ptr, const char *str)
+static void link_print(struct tipc_link *l, const char *str)
 {
-	struct tipc_net *tn = net_generic(l_ptr->owner->net, tipc_net_id);
-	struct tipc_bearer *b_ptr;
-
-	rcu_read_lock();
-	b_ptr = rcu_dereference_rtnl(tn->bearer_list[l_ptr->bearer_id]);
-	if (b_ptr)
-		pr_info("%s Link %x<%s>:", str, l_ptr->addr, b_ptr->name);
-	rcu_read_unlock();
-
-	if (link_working_unknown(l_ptr))
-		pr_cont(":WU\n");
-	else if (link_reset_reset(l_ptr))
-		pr_cont(":RR\n");
-	else if (link_reset_unknown(l_ptr))
-		pr_cont(":RU\n");
-	else if (link_working_working(l_ptr))
-		pr_cont(":WW\n");
-	else
-		pr_cont("\n");
+	struct sk_buff *hskb = skb_peek(&l->transmq);
+	u16 head = hskb ? msg_seqno(buf_msg(hskb)) : l->snd_nxt;
+	u16 tail = l->snd_nxt - 1;
+
+	pr_info("%s Link <%s> state %x\n", str, l->name, l->state);
+	pr_info("XMTQ: %u [%u-%u], BKLGQ: %u, SNDNX: %u, RCVNX: %u\n",
+		skb_queue_len(&l->transmq), head, tail,
+		skb_queue_len(&l->backlogq), l->snd_nxt, l->rcv_nxt);
 }
 
 /* Parse and validate nested (link) properties valid for media, bearer and link
@@ -1865,7 +1561,7 @@ int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
 
 	tipc_node_lock(node);
 
-	link = node->links[bearer_id];
+	link = node->links[bearer_id].link;
 	if (!link) {
 		res = -EINVAL;
 		goto out;
@@ -1885,7 +1581,7 @@ int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
 			u32 tol;
 
 			tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
-			link_set_supervision_props(link, tol);
+			link->tolerance = tol;
 			tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0);
 		}
 		if (props[TIPC_NLA_PROP_PRIO]) {
@@ -2055,10 +1751,11 @@ static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
 	for (i = *prev_link; i < MAX_BEARERS; i++) {
 		*prev_link = i;
 
-		if (!node->links[i])
+		if (!node->links[i].link)
 			continue;
 
-		err = __tipc_nl_add_link(net, msg, node->links[i], NLM_F_MULTI);
+		err = __tipc_nl_add_link(net, msg,
+					 node->links[i].link, NLM_F_MULTI);
 		if (err)
 			return err;
 	}
@@ -2172,7 +1869,7 @@ int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
 			return -EINVAL;
 
 		tipc_node_lock(node);
-		link = node->links[bearer_id];
+		link = node->links[bearer_id].link;
 		if (!link) {
 			tipc_node_unlock(node);
 			nlmsg_free(msg.skb);
@@ -2227,7 +1924,7 @@ int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
 
 	tipc_node_lock(node);
 
-	link = node->links[bearer_id];
+	link = node->links[bearer_id].link;
 	if (!link) {
 		tipc_node_unlock(node);
 		return -EINVAL;