Initial import

1 files changed, 2272 insertions, 0 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
new file mode 100644
index 000000000..43a515dc9
--- /dev/null
+++ b/net/tipc/link.c
@@ -0,0 +1,2272 @@
+/*
+ * net/tipc/link.c: TIPC link code
+ *
+ * Copyright (c) 1996-2007, 2012-2015, Ericsson AB
+ * Copyright (c) 2004-2007, 2010-2013, Wind River Systems
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "core.h"
+#include "subscr.h"
+#include "link.h"
+#include "bcast.h"
+#include "socket.h"
+#include "name_distr.h"
+#include "discover.h"
+#include "netlink.h"
+
+#include <linux/pkt_sched.h>
+
+/*
+ * Error message prefixes
+ */
+static const char *link_co_err = "Link changeover 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 },
+	[TIPC_NLA_LINK_NAME] = {
+		.type = NLA_STRING,
+		.len = TIPC_MAX_LINK_NAME
+	},
+	[TIPC_NLA_LINK_MTU]		= { .type = NLA_U32 },
+	[TIPC_NLA_LINK_BROADCAST]	= { .type = NLA_FLAG },
+	[TIPC_NLA_LINK_UP]		= { .type = NLA_FLAG },
+	[TIPC_NLA_LINK_ACTIVE]		= { .type = NLA_FLAG },
+	[TIPC_NLA_LINK_PROP]		= { .type = NLA_NESTED },
+	[TIPC_NLA_LINK_STATS]		= { .type = NLA_NESTED },
+	[TIPC_NLA_LINK_RX]		= { .type = NLA_U32 },
+	[TIPC_NLA_LINK_TX]		= { .type = NLA_U32 }
+};
+
+/* Properties valid for media, bearar and link */
+static const struct nla_policy tipc_nl_prop_policy[TIPC_NLA_PROP_MAX + 1] = {
+	[TIPC_NLA_PROP_UNSPEC]		= { .type = NLA_UNSPEC },
+	[TIPC_NLA_PROP_PRIO]		= { .type = NLA_U32 },
+	[TIPC_NLA_PROP_TOL]		= { .type = NLA_U32 },
+	[TIPC_NLA_PROP_WIN]		= { .type = NLA_U32 }
+};
+
+/*
+ * Out-of-range value for link session numbers
+ */
+#define INVALID_SESSION 0x10000
+
+/*
+ * Link state events:
+ */
+#define  STARTING_EVT    856384768	/* link processing trigger */
+#define  TRAFFIC_MSG_EVT 560815u	/* rx'd ??? */
+#define  TIMEOUT_EVT     560817u	/* link timer expired */
+
+/*
+ * State value stored in 'failover_pkts'
+ */
+#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 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);
+/*
+ *  Simple link routines
+ */
+static unsigned int align(unsigned int i)
+{
+	return (i + 3) & ~3u;
+}
+
+static void tipc_link_release(struct kref *kref)
+{
+	kfree(container_of(kref, struct tipc_link, ref));
+}
+
+static void tipc_link_get(struct tipc_link *l_ptr)
+{
+	kref_get(&l_ptr->ref);
+}
+
+static void tipc_link_put(struct tipc_link *l_ptr)
+{
+	kref_put(&l_ptr->ref, tipc_link_release);
+}
+
+static struct tipc_link *tipc_parallel_link(struct tipc_link *l)
+{
+	if (l->owner->active_links[0] != l)
+		return l->owner->active_links[0];
+	return l->owner->active_links[1];
+}
+
+/*
+ *  Simple non-static link routines (i.e. referenced outside this file)
+ */
+int tipc_link_is_up(struct tipc_link *l_ptr)
+{
+	if (!l_ptr)
+		return 0;
+	return link_working_working(l_ptr) || link_working_unknown(l_ptr);
+}
+
+int tipc_link_is_active(struct tipc_link *l_ptr)
+{
+	return	(l_ptr->owner->active_links[0] == l_ptr) ||
+		(l_ptr->owner->active_links[1] == l_ptr);
+}
+
+/**
+ * link_timeout - handle expiration of link timer
+ * @l_ptr: pointer to link
+ */
+static void link_timeout(unsigned long data)
+{
+	struct tipc_link *l_ptr = (struct tipc_link *)data;
+	struct sk_buff *skb;
+
+	tipc_node_lock(l_ptr->owner);
+
+	/* 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 = skb_peek(&l_ptr->transmq);
+	if (skb) {
+		struct tipc_msg *msg = buf_msg(skb);
+		u32 length = msg_size(msg);
+
+		if ((msg_user(msg) == MSG_FRAGMENTER) &&
+		    (msg_type(msg) == FIRST_FRAGMENT)) {
+			length = msg_size(msg_get_wrapped(msg));
+		}
+		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]++;
+		}
+	}
+
+	/* do all other link processing performed on a periodic basis */
+	link_state_event(l_ptr, TIMEOUT_EVT);
+
+	if (skb_queue_len(&l_ptr->backlogq))
+		tipc_link_push_packets(l_ptr);
+
+	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);
+}
+
+/**
+ * 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.
+ */
+struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
+				   struct tipc_bearer *b_ptr,
+				   const struct tipc_media_addr *media_addr)
+{
+	struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
+	struct tipc_link *l_ptr;
+	struct tipc_msg *msg;
+	char *if_name;
+	char addr_string[16];
+	u32 peer = n_ptr->addr;
+
+	if (n_ptr->link_cnt >= MAX_BEARERS) {
+		tipc_addr_string_fill(addr_string, n_ptr->addr);
+		pr_err("Attempt to establish %uth link to %s. Max %u allowed.\n",
+			n_ptr->link_cnt, addr_string, MAX_BEARERS);
+		return NULL;
+	}
+
+	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;
+	}
+
+	l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
+	if (!l_ptr) {
+		pr_warn("Link creation failed, no memory\n");
+		return NULL;
+	}
+	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->checkpoint = 1;
+	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->next_out_no = 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;
+}
+
+/**
+ * tipc_link_delete - Delete a link
+ * @l: link to be deleted
+ */
+void tipc_link_delete(struct tipc_link *l)
+{
+	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);
+}
+
+void tipc_link_delete_list(struct net *net, unsigned int bearer_id,
+			   bool shutting_down)
+{
+	struct tipc_net *tn = net_generic(net, tipc_net_id);
+	struct tipc_link *link;
+	struct tipc_node *node;
+
+	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();
+}
+
+/**
+ * link_schedule_user - schedule a message sender for wakeup after congestion
+ * @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
+ */
+static int link_schedule_user(struct tipc_link *link, struct sk_buff_head *list)
+{
+	struct tipc_msg *msg = buf_msg(skb_peek(list));
+	int imp = msg_importance(msg);
+	u32 oport = msg_origport(msg);
+	u32 addr = link_own_addr(link);
+	struct sk_buff *skb;
+
+	/* 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;
+	}
+	/* Non-blocking sender: */
+	if (TIPC_SKB_CB(skb_peek(list))->wakeup_pending)
+		return -ELINKCONG;
+
+	/* Create and schedule wakeup pseudo message */
+	skb = tipc_msg_create(SOCK_WAKEUP, 0, INT_H_SIZE, 0,
+			      addr, addr, oport, 0, 0);
+	if (!skb)
+		goto err;
+	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;
+}
+
+/**
+ * link_prepare_wakeup - prepare users for wakeup after congestion
+ * @link: congested link
+ * Move a number of waiting users, as permitted by available space in
+ * the send queue, from link wait queue to node wait queue for wakeup
+ */
+void link_prepare_wakeup(struct tipc_link *l)
+{
+	int pnd[TIPC_SYSTEM_IMPORTANCE + 1] = {0,};
+	int imp, lim;
+	struct sk_buff *skb, *tmp;
+
+	skb_queue_walk_safe(&l->wakeupq, skb, tmp) {
+		imp = TIPC_SKB_CB(skb)->chain_imp;
+		lim = l->window + l->backlog[imp].limit;
+		pnd[imp] += TIPC_SKB_CB(skb)->chain_sz;
+		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;
+	}
+}
+
+/**
+ * tipc_link_reset_fragments - purge link's inbound message fragments queue
+ * @l_ptr: pointer to link
+ */
+void tipc_link_reset_fragments(struct tipc_link *l_ptr)
+{
+	kfree_skb(l_ptr->reasm_buf);
+	l_ptr->reasm_buf = NULL;
+}
+
+static void tipc_link_purge_backlog(struct tipc_link *l)
+{
+	__skb_queue_purge(&l->backlogq);
+	l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
+	l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
+	l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
+	l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
+	l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
+}
+
+/**
+ * tipc_link_purge_queues - purge all pkt queues associated with link
+ * @l_ptr: pointer to link
+ */
+void tipc_link_purge_queues(struct tipc_link *l_ptr)
+{
+	__skb_queue_purge(&l_ptr->deferdq);
+	__skb_queue_purge(&l_ptr->transmq);
+	tipc_link_purge_backlog(l_ptr);
+	tipc_link_reset_fragments(l_ptr);
+}
+
+void tipc_link_reset(struct tipc_link *l_ptr)
+{
+	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));
+
+	/* 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;
+
+	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 (was_active_link && tipc_node_is_up(l_ptr->owner) && (pl != l_ptr)) {
+		l_ptr->flags |= LINK_FAILINGOVER;
+		l_ptr->failover_checkpt = l_ptr->next_in_no;
+		pl->failover_pkts = FIRST_FAILOVER;
+		pl->failover_checkpt = l_ptr->next_in_no;
+		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->checkpoint = 1;
+	l_ptr->next_out_no = 1;
+	l_ptr->fsm_msg_cnt = 0;
+	l_ptr->stale_count = 0;
+	link_reset_statistics(l_ptr);
+}
+
+void tipc_link_reset_list(struct net *net, unsigned int bearer_id)
+{
+	struct tipc_net *tn = net_generic(net, tipc_net_id);
+	struct tipc_link *l_ptr;
+	struct tipc_node *n_ptr;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(n_ptr, &tn->node_list, list) {
+		tipc_node_lock(n_ptr);
+		l_ptr = n_ptr->links[bearer_id];
+		if (l_ptr)
+			tipc_link_reset(l_ptr);
+		tipc_node_unlock(n_ptr);
+	}
+	rcu_read_unlock();
+}
+
+static void link_activate(struct tipc_link *link)
+{
+	struct tipc_node *node = link->owner;
+
+	link->next_in_no = 1;
+	link->stats.recv_info = 1;
+	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 cont_intv = l_ptr->cont_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) {
+		if (event == TIMEOUT_EVT)
+			link_set_timer(l_ptr, cont_intv);
+		return;
+	}
+
+	switch (l_ptr->state) {
+	case WORKING_WORKING:
+		switch (event) {
+		case TRAFFIC_MSG_EVT:
+		case ACTIVATE_MSG:
+			break;
+		case TIMEOUT_EVT:
+			if (l_ptr->next_in_no != l_ptr->checkpoint) {
+				l_ptr->checkpoint = l_ptr->next_in_no;
+				if (tipc_bclink_acks_missing(l_ptr->owner)) {
+					tipc_link_proto_xmit(l_ptr, STATE_MSG,
+							     0, 0, 0, 0);
+					l_ptr->fsm_msg_cnt++;
+				}
+				link_set_timer(l_ptr, cont_intv);
+				break;
+			}
+			l_ptr->state = WORKING_UNKNOWN;
+			l_ptr->fsm_msg_cnt = 0;
+			tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0);
+			l_ptr->fsm_msg_cnt++;
+			link_set_timer(l_ptr, cont_intv / 4);
+			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;
+			l_ptr->fsm_msg_cnt = 0;
+			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
+					     0, 0, 0, 0);
+			l_ptr->fsm_msg_cnt++;
+			link_set_timer(l_ptr, cont_intv);
+			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->fsm_msg_cnt = 0;
+			link_set_timer(l_ptr, cont_intv);
+			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;
+			l_ptr->fsm_msg_cnt = 0;
+			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
+					     0, 0, 0, 0);
+			l_ptr->fsm_msg_cnt++;
+			link_set_timer(l_ptr, cont_intv);
+			break;
+		case TIMEOUT_EVT:
+			if (l_ptr->next_in_no != l_ptr->checkpoint) {
+				l_ptr->state = WORKING_WORKING;
+				l_ptr->fsm_msg_cnt = 0;
+				l_ptr->checkpoint = l_ptr->next_in_no;
+				if (tipc_bclink_acks_missing(l_ptr->owner)) {
+					tipc_link_proto_xmit(l_ptr, STATE_MSG,
+							     0, 0, 0, 0);
+					l_ptr->fsm_msg_cnt++;
+				}
+				link_set_timer(l_ptr, cont_intv);
+			} else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
+				tipc_link_proto_xmit(l_ptr, STATE_MSG,
+						     1, 0, 0, 0);
+				l_ptr->fsm_msg_cnt++;
+				link_set_timer(l_ptr, cont_intv / 4);
+			} 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;
+				l_ptr->fsm_msg_cnt = 0;
+				tipc_link_proto_xmit(l_ptr, RESET_MSG,
+						     0, 0, 0, 0);
+				l_ptr->fsm_msg_cnt++;
+				link_set_timer(l_ptr, cont_intv);
+			}
+			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;
+			l_ptr->fsm_msg_cnt = 0;
+			link_activate(l_ptr);
+			tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0);
+			l_ptr->fsm_msg_cnt++;
+			if (l_ptr->owner->working_links == 1)
+				tipc_link_sync_xmit(l_ptr);
+			link_set_timer(l_ptr, cont_intv);
+			break;
+		case RESET_MSG:
+			l_ptr->state = RESET_RESET;
+			l_ptr->fsm_msg_cnt = 0;
+			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
+					     1, 0, 0, 0);
+			l_ptr->fsm_msg_cnt++;
+			link_set_timer(l_ptr, cont_intv);
+			break;
+		case STARTING_EVT:
+			l_ptr->flags |= LINK_STARTED;
+			l_ptr->fsm_msg_cnt++;
+			link_set_timer(l_ptr, cont_intv);
+			break;
+		case TIMEOUT_EVT:
+			tipc_link_proto_xmit(l_ptr, RESET_MSG, 0, 0, 0, 0);
+			l_ptr->fsm_msg_cnt++;
+			link_set_timer(l_ptr, cont_intv);
+			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;
+			l_ptr->fsm_msg_cnt = 0;
+			link_activate(l_ptr);
+			tipc_link_proto_xmit(l_ptr, STATE_MSG, 1, 0, 0, 0);
+			l_ptr->fsm_msg_cnt++;
+			if (l_ptr->owner->working_links == 1)
+				tipc_link_sync_xmit(l_ptr);
+			link_set_timer(l_ptr, cont_intv);
+			break;
+		case RESET_MSG:
+			break;
+		case TIMEOUT_EVT:
+			tipc_link_proto_xmit(l_ptr, ACTIVATE_MSG,
+					     0, 0, 0, 0);
+			l_ptr->fsm_msg_cnt++;
+			link_set_timer(l_ptr, cont_intv);
+			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);
+	}
+}
+
+/**
+ * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
+ * @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.
+ * 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 tipc_link *link,
+		     struct sk_buff_head *list)
+{
+	struct tipc_msg *msg = buf_msg(skb_peek(list));
+	unsigned int maxwin = link->window;
+	unsigned int imp = msg_importance(msg);
+	uint mtu = link->mtu;
+	uint ack = mod(link->next_in_no - 1);
+	uint seqno = link->next_out_no;
+	uint bc_last_in = link->owner->bclink.last_in;
+	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, *tmp;
+
+	/* Match backlog limit against msg importance: */
+	if (unlikely(link->backlog[imp].len >= link->backlog[imp].limit))
+		return link_schedule_user(link, list);
+
+	if (unlikely(msg_size(msg) > mtu)) {
+		__skb_queue_purge(list);
+		return -EMSGSIZE;
+	}
+	/* Prepare each packet for sending, and add to relevant queue: */
+	skb_queue_walk_safe(list, skb, tmp) {
+		__skb_unlink(skb, list);
+		msg = buf_msg(skb);
+		msg_set_seqno(msg, seqno);
+		msg_set_ack(msg, ack);
+		msg_set_bcast_ack(msg, bc_last_in);
+
+		if (likely(skb_queue_len(transmq) < maxwin)) {
+			__skb_queue_tail(transmq, skb);
+			tipc_bearer_send(net, link->bearer_id, skb, addr);
+			link->rcv_unacked = 0;
+			seqno++;
+			continue;
+		}
+		if (tipc_msg_bundle(skb_peek_tail(backlogq), skb, mtu)) {
+			link->stats.sent_bundled++;
+			continue;
+		}
+		if (tipc_msg_make_bundle(&skb, mtu, link->addr)) {
+			link->stats.sent_bundled++;
+			link->stats.sent_bundles++;
+			imp = msg_importance(buf_msg(skb));
+		}
+		__skb_queue_tail(backlogq, skb);
+		link->backlog[imp].len++;
+		seqno++;
+	}
+	link->next_out_no = seqno;
+	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
+ * @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
+ */
+int tipc_link_xmit(struct net *net, struct sk_buff_head *list, u32 dnode,
+		   u32 selector)
+{
+	struct tipc_link *link = NULL;
+	struct tipc_node *node;
+	int rc = -EHOSTUNREACH;
+
+	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;
+	}
+
+	__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;
+
+	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);
+}
+
+/*
+ * tipc_link_sync_rcv - synchronize broadcast link endpoints.
+ * Receive the sequence number where we should start receiving and
+ * acking broadcast packets from a newly added peer node, and open
+ * up for reception of such packets.
+ *
+ * Called with node locked
+ */
+static void tipc_link_sync_rcv(struct tipc_node *n, struct sk_buff *buf)
+{
+	struct tipc_msg *msg = buf_msg(buf);
+
+	n->bclink.last_sent = n->bclink.last_in = msg_last_bcast(msg);
+	n->bclink.recv_permitted = true;
+	kfree_skb(buf);
+}
+
+/*
+ * tipc_link_push_packets - push unsent packets to bearer
+ *
+ * Push out the unsent messages of a link where congestion
+ * has abated. Node is locked.
+ *
+ * Called with node locked
+ */
+void tipc_link_push_packets(struct tipc_link *link)
+{
+	struct sk_buff *skb;
+	struct tipc_msg *msg;
+	unsigned int ack = mod(link->next_in_no - 1);
+
+	while (skb_queue_len(&link->transmq) < link->window) {
+		skb = __skb_dequeue(&link->backlogq);
+		if (!skb)
+			break;
+		msg = buf_msg(skb);
+		link->backlog[msg_importance(msg)].len--;
+		msg_set_ack(msg, ack);
+		msg_set_bcast_ack(msg, link->owner->bclink.last_in);
+		link->rcv_unacked = 0;
+		__skb_queue_tail(&link->transmq, skb);
+		tipc_bearer_send(link->owner->net, link->bearer_id,
+				 skb, &link->media_addr);
+	}
+}
+
+void tipc_link_reset_all(struct tipc_node *node)
+{
+	char addr_string[16];
+	u32 i;
+
+	tipc_node_lock(node);
+
+	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]);
+		}
+	}
+
+	tipc_node_unlock(node);
+}
+
+static void link_retransmit_failure(struct tipc_link *l_ptr,
+				    struct sk_buff *buf)
+{
+	struct tipc_msg *msg = buf_msg(buf);
+	struct net *net = l_ptr->owner->net;
+
+	pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);
+
+	if (l_ptr->addr) {
+		/* Handle failure on standard link */
+		link_print(l_ptr, "Resetting link\n");
+		tipc_link_reset(l_ptr);
+
+	} else {
+		/* Handle failure on broadcast link */
+		struct tipc_node *n_ptr;
+		char addr_string[16];
+
+		pr_info("Msg seq number: %u,  ", msg_seqno(msg));
+		pr_cont("Outstanding acks: %lu\n",
+			(unsigned long) TIPC_SKB_CB(buf)->handle);
+
+		n_ptr = tipc_bclink_retransmit_to(net);
+
+		tipc_addr_string_fill(addr_string, n_ptr->addr);
+		pr_info("Broadcast link info for %s\n", addr_string);
+		pr_info("Reception permitted: %d,  Acked: %u\n",
+			n_ptr->bclink.recv_permitted,
+			n_ptr->bclink.acked);
+		pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
+			n_ptr->bclink.last_in,
+			n_ptr->bclink.oos_state,
+			n_ptr->bclink.last_sent);
+
+		n_ptr->action_flags |= TIPC_BCAST_RESET;
+		l_ptr->stale_count = 0;
+	}
+}
+
+void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
+			  u32 retransmits)
+{
+	struct tipc_msg *msg;
+
+	if (!skb)
+		return;
+
+	msg = buf_msg(skb);
+
+	/* Detect repeated retransmit failures */
+	if (l_ptr->last_retransmitted == msg_seqno(msg)) {
+		if (++l_ptr->stale_count > 100) {
+			link_retransmit_failure(l_ptr, skb);
+			return;
+		}
+	} else {
+		l_ptr->last_retransmitted = msg_seqno(msg);
+		l_ptr->stale_count = 1;
+	}
+
+	skb_queue_walk_from(&l_ptr->transmq, skb) {
+		if (!retransmits)
+			break;
+		msg = buf_msg(skb);
+		msg_set_ack(msg, mod(l_ptr->next_in_no - 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);
+		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)
+{
+	unsigned int post_synch;
+	struct tipc_link *pl;
+
+	pl  = tipc_parallel_link(l);
+	if (pl == l)
+		goto synched;
+
+	/* Was last pre-synch packet added to input queue ? */
+	if (less_eq(pl->next_in_no, l->synch_point))
+		return false;
+
+	/* Is it still in the input queue ? */
+	post_synch = mod(pl->next_in_no - 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)
+{
+	u32 seq_no;
+
+	if (skb_queue_empty(&link->deferdq))
+		return;
+
+	seq_no = buf_seqno(skb_peek(&link->deferdq));
+	if (seq_no == mod(link->next_in_no))
+		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;
+	u32 seq_no;
+	u32 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 != mod(l_ptr->next_in_no))) {
+			link_handle_out_of_seq_msg(l_ptr, skb);
+			link_retrieve_defq(l_ptr, &head);
+			skb = NULL;
+			goto unlock;
+		}
+		/* 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->next_in_no++;
+		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);
+	}
+}
+
+/* tipc_data_input - deliver data and name distr msgs to upper layer
+ *
+ * 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)
+{
+	struct tipc_node *node = link->owner;
+	struct tipc_msg *msg = buf_msg(skb);
+	u32 dport = msg_destport(msg);
+
+	switch (msg_user(msg)) {
+	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;
+		}
+		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;
+		return true;
+	case MSG_BUNDLER:
+	case TUNNEL_PROTOCOL:
+	case MSG_FRAGMENTER:
+	case BCAST_PROTOCOL:
+		return false;
+	default:
+		pr_warn("Dropping received illegal msg type\n");
+		kfree_skb(skb);
+		return false;
+	};
+}
+
+/* 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)
+{
+	struct tipc_node *node = link->owner;
+	struct tipc_msg *msg = buf_msg(skb);
+	struct sk_buff *iskb;
+	int pos = 0;
+
+	if (likely(tipc_data_input(link, skb)))
+		return;
+
+	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 (!tipc_link_failover_rcv(link, &skb))
+			break;
+		if (msg_user(buf_msg(skb)) != MSG_BUNDLER) {
+			tipc_data_input(link, skb);
+			break;
+		}
+	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);
+		}
+		break;
+	case BCAST_PROTOCOL:
+		tipc_link_sync_rcv(node, skb);
+		break;
+	default:
+		break;
+	};
+}
+
+/**
+ * tipc_link_defer_pkt - Add out-of-sequence message to deferred reception queue
+ *
+ * Returns increase in queue length (i.e. 0 or 1)
+ */
+u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
+{
+	struct sk_buff *skb1;
+	u32 seq_no = buf_seqno(skb);
+
+	/* Empty queue ? */
+	if (skb_queue_empty(list)) {
+		__skb_queue_tail(list, skb);
+		return 1;
+	}
+
+	/* Last ? */
+	if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
+		__skb_queue_tail(list, skb);
+		return 1;
+	}
+
+	/* Locate insertion point in queue, then insert; discard if duplicate */
+	skb_queue_walk(list, skb1) {
+		u32 curr_seqno = buf_seqno(skb1);
+
+		if (seq_no == curr_seqno) {
+			kfree_skb(skb);
+			return 0;
+		}
+
+		if (less(seq_no, curr_seqno))
+			break;
+	}
+
+	__skb_queue_before(list, skb1, skb);
+	return 1;
+}
+
+/*
+ * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
+ */
+static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
+				       struct sk_buff *buf)
+{
+	u32 seq_no = buf_seqno(buf);
+
+	if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
+		tipc_link_proto_rcv(l_ptr, buf);
+		return;
+	}
+
+	/* Record OOS packet arrival (force mismatch on next timeout) */
+	l_ptr->checkpoint--;
+
+	/*
+	 * Discard packet if a duplicate; otherwise add it to deferred queue
+	 * and notify peer of gap as per protocol specification
+	 */
+	if (less(seq_no, mod(l_ptr->next_in_no))) {
+		l_ptr->stats.duplicates++;
+		kfree_skb(buf);
+		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);
+	} else {
+		l_ptr->stats.duplicates++;
+	}
+}
+
+/*
+ * Send protocol message to the other endpoint.
+ */
+void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int probe_msg,
+			  u32 gap, u32 tolerance, u32 priority)
+{
+	struct sk_buff *buf = NULL;
+	struct tipc_msg *msg = l_ptr->pmsg;
+	u32 msg_size = sizeof(l_ptr->proto_msg);
+	int r_flag;
+
+	/* Don't send protocol message during link failover */
+	if (l_ptr->flags & LINK_FAILINGOVER)
+		return;
+
+	/* Abort non-RESET send if communication with node is prohibited */
+	if ((tipc_node_blocked(l_ptr->owner)) && (msg_typ != RESET_MSG))
+		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) {
+		u32 next_sent = mod(l_ptr->next_out_no);
+
+		if (!tipc_link_is_up(l_ptr))
+			return;
+		if (skb_queue_len(&l_ptr->backlogq))
+			next_sent = buf_seqno(skb_peek(&l_ptr->backlogq));
+		msg_set_next_sent(msg, next_sent);
+		if (!skb_queue_empty(&l_ptr->deferdq)) {
+			u32 rec = buf_seqno(skb_peek(&l_ptr->deferdq));
+			gap = mod(rec - mod(l_ptr->next_in_no));
+		}
+		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->next_in_no - 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);
+	}
+
+	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->next_out_no + (0xffff/2)));
+
+	buf = tipc_buf_acquire(msg_size);
+	if (!buf)
+		return;
+
+	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);
+}
+
+/*
+ * Receive protocol message :
+ * Note that network plane id propagates through the network, and may
+ * change at any time. The node with lowest address rules
+ */
+static void tipc_link_proto_rcv(struct tipc_link *l_ptr,
+				struct sk_buff *buf)
+{
+	u32 rec_gap = 0;
+	u32 msg_tol;
+	struct tipc_msg *msg = buf_msg(buf);
+
+	if (l_ptr->flags & LINK_FAILINGOVER)
+		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)) {
+
+	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);
+
+		/* 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:
+
+		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 */
+			break;
+		}
+
+		/* Record reception; force mismatch at next timeout: */
+		l_ptr->checkpoint--;
+
+		link_state_event(l_ptr, TRAFFIC_MSG_EVT);
+		l_ptr->stats.recv_states++;
+		if (link_reset_unknown(l_ptr))
+			break;
+
+		if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
+			rec_gap = mod(msg_next_sent(msg) -
+				      mod(l_ptr->next_in_no));
+		}
+
+		if (msg_probe(msg))
+			l_ptr->stats.recv_probes++;
+
+		/* 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));
+		}
+		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_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]);
+
+	skb_queue_walk(&l_ptr->transmq, skb) {
+		struct tipc_msg *msg = buf_msg(skb);
+
+		if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
+			struct tipc_msg *m = msg_get_wrapped(msg);
+			unchar *pos = (unchar *)m;
+
+			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));
+		}
+	}
+}
+
+/* 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;
+
+	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->next_in_no - 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;
+	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);
+	}
+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->cont_intv = msecs_to_jiffies(intv);
+	l_ptr->abort_limit = tol / (jiffies_to_msecs(l_ptr->cont_intv) / 4);
+}
+
+void tipc_link_set_queue_limits(struct tipc_link *l, u32 win)
+{
+	int max_bulk = TIPC_MAX_PUBLICATIONS / (l->mtu / ITEM_SIZE);
+
+	l->window = win;
+	l->backlog[TIPC_LOW_IMPORTANCE].limit      = win / 2;
+	l->backlog[TIPC_MEDIUM_IMPORTANCE].limit   = win;
+	l->backlog[TIPC_HIGH_IMPORTANCE].limit     = win / 2 * 3;
+	l->backlog[TIPC_CRITICAL_IMPORTANCE].limit = win * 2;
+	l->backlog[TIPC_SYSTEM_IMPORTANCE].limit   = max_bulk;
+}
+
+/* tipc_link_find_owner - locate owner node of link by link's name
+ * @net: the applicable net namespace
+ * @name: pointer to link name string
+ * @bearer_id: pointer to index in 'node->links' array where the link was found.
+ *
+ * Returns pointer to node owning the link, or 0 if no matching link is found.
+ */
+static struct tipc_node *tipc_link_find_owner(struct net *net,
+					      const char *link_name,
+					      unsigned int *bearer_id)
+{
+	struct tipc_net *tn = net_generic(net, tipc_net_id);
+	struct tipc_link *l_ptr;
+	struct tipc_node *n_ptr;
+	struct tipc_node *found_node = NULL;
+	int i;
+
+	*bearer_id = 0;
+	rcu_read_lock();
+	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];
+			if (l_ptr && !strcmp(l_ptr->name, link_name)) {
+				*bearer_id = i;
+				found_node = n_ptr;
+				break;
+			}
+		}
+		tipc_node_unlock(n_ptr);
+		if (found_node)
+			break;
+	}
+	rcu_read_unlock();
+
+	return found_node;
+}
+
+/**
+ * link_reset_statistics - reset link statistics
+ * @l_ptr: pointer to link
+ */
+static void link_reset_statistics(struct tipc_link *l_ptr)
+{
+	memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
+	l_ptr->stats.sent_info = l_ptr->next_out_no;
+	l_ptr->stats.recv_info = l_ptr->next_in_no;
+}
+
+static void link_print(struct tipc_link *l_ptr, 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");
+}
+
+/* Parse and validate nested (link) properties valid for media, bearer and link
+ */
+int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[])
+{
+	int err;
+
+	err = nla_parse_nested(props, TIPC_NLA_PROP_MAX, prop,
+			       tipc_nl_prop_policy);
+	if (err)
+		return err;
+
+	if (props[TIPC_NLA_PROP_PRIO]) {
+		u32 prio;
+
+		prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
+		if (prio > TIPC_MAX_LINK_PRI)
+			return -EINVAL;
+	}
+
+	if (props[TIPC_NLA_PROP_TOL]) {
+		u32 tol;
+
+		tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
+		if ((tol < TIPC_MIN_LINK_TOL) || (tol > TIPC_MAX_LINK_TOL))
+			return -EINVAL;
+	}
+
+	if (props[TIPC_NLA_PROP_WIN]) {
+		u32 win;
+
+		win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
+		if ((win < TIPC_MIN_LINK_WIN) || (win > TIPC_MAX_LINK_WIN))
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info)
+{
+	int err;
+	int res = 0;
+	int bearer_id;
+	char *name;
+	struct tipc_link *link;
+	struct tipc_node *node;
+	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
+	struct net *net = sock_net(skb->sk);
+
+	if (!info->attrs[TIPC_NLA_LINK])
+		return -EINVAL;
+
+	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
+			       info->attrs[TIPC_NLA_LINK],
+			       tipc_nl_link_policy);
+	if (err)
+		return err;
+
+	if (!attrs[TIPC_NLA_LINK_NAME])
+		return -EINVAL;
+
+	name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
+
+	node = tipc_link_find_owner(net, name, &bearer_id);
+	if (!node)
+		return -EINVAL;
+
+	tipc_node_lock(node);
+
+	link = node->links[bearer_id];
+	if (!link) {
+		res = -EINVAL;
+		goto out;
+	}
+
+	if (attrs[TIPC_NLA_LINK_PROP]) {
+		struct nlattr *props[TIPC_NLA_PROP_MAX + 1];
+
+		err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP],
+					      props);
+		if (err) {
+			res = err;
+			goto out;
+		}
+
+		if (props[TIPC_NLA_PROP_TOL]) {
+			u32 tol;
+
+			tol = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
+			link_set_supervision_props(link, tol);
+			tipc_link_proto_xmit(link, STATE_MSG, 0, 0, tol, 0);
+		}
+		if (props[TIPC_NLA_PROP_PRIO]) {
+			u32 prio;
+
+			prio = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
+			link->priority = prio;
+			tipc_link_proto_xmit(link, STATE_MSG, 0, 0, 0, prio);
+		}
+		if (props[TIPC_NLA_PROP_WIN]) {
+			u32 win;
+
+			win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);
+			tipc_link_set_queue_limits(link, win);
+		}
+	}
+
+out:
+	tipc_node_unlock(node);
+
+	return res;
+}
+
+static int __tipc_nl_add_stats(struct sk_buff *skb, struct tipc_stats *s)
+{
+	int i;
+	struct nlattr *stats;
+
+	struct nla_map {
+		u32 key;
+		u32 val;
+	};
+
+	struct nla_map map[] = {
+		{TIPC_NLA_STATS_RX_INFO, s->recv_info},
+		{TIPC_NLA_STATS_RX_FRAGMENTS, s->recv_fragments},
+		{TIPC_NLA_STATS_RX_FRAGMENTED, s->recv_fragmented},
+		{TIPC_NLA_STATS_RX_BUNDLES, s->recv_bundles},
+		{TIPC_NLA_STATS_RX_BUNDLED, s->recv_bundled},
+		{TIPC_NLA_STATS_TX_INFO, s->sent_info},
+		{TIPC_NLA_STATS_TX_FRAGMENTS, s->sent_fragments},
+		{TIPC_NLA_STATS_TX_FRAGMENTED, s->sent_fragmented},
+		{TIPC_NLA_STATS_TX_BUNDLES, s->sent_bundles},
+		{TIPC_NLA_STATS_TX_BUNDLED, s->sent_bundled},
+		{TIPC_NLA_STATS_MSG_PROF_TOT, (s->msg_length_counts) ?
+			s->msg_length_counts : 1},
+		{TIPC_NLA_STATS_MSG_LEN_CNT, s->msg_length_counts},
+		{TIPC_NLA_STATS_MSG_LEN_TOT, s->msg_lengths_total},
+		{TIPC_NLA_STATS_MSG_LEN_P0, s->msg_length_profile[0]},
+		{TIPC_NLA_STATS_MSG_LEN_P1, s->msg_length_profile[1]},
+		{TIPC_NLA_STATS_MSG_LEN_P2, s->msg_length_profile[2]},
+		{TIPC_NLA_STATS_MSG_LEN_P3, s->msg_length_profile[3]},
+		{TIPC_NLA_STATS_MSG_LEN_P4, s->msg_length_profile[4]},
+		{TIPC_NLA_STATS_MSG_LEN_P5, s->msg_length_profile[5]},
+		{TIPC_NLA_STATS_MSG_LEN_P6, s->msg_length_profile[6]},
+		{TIPC_NLA_STATS_RX_STATES, s->recv_states},
+		{TIPC_NLA_STATS_RX_PROBES, s->recv_probes},
+		{TIPC_NLA_STATS_RX_NACKS, s->recv_nacks},
+		{TIPC_NLA_STATS_RX_DEFERRED, s->deferred_recv},
+		{TIPC_NLA_STATS_TX_STATES, s->sent_states},
+		{TIPC_NLA_STATS_TX_PROBES, s->sent_probes},
+		{TIPC_NLA_STATS_TX_NACKS, s->sent_nacks},
+		{TIPC_NLA_STATS_TX_ACKS, s->sent_acks},
+		{TIPC_NLA_STATS_RETRANSMITTED, s->retransmitted},
+		{TIPC_NLA_STATS_DUPLICATES, s->duplicates},
+		{TIPC_NLA_STATS_LINK_CONGS, s->link_congs},
+		{TIPC_NLA_STATS_MAX_QUEUE, s->max_queue_sz},
+		{TIPC_NLA_STATS_AVG_QUEUE, s->queue_sz_counts ?
+			(s->accu_queue_sz / s->queue_sz_counts) : 0}
+	};
+
+	stats = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
+	if (!stats)
+		return -EMSGSIZE;
+
+	for (i = 0; i <  ARRAY_SIZE(map); i++)
+		if (nla_put_u32(skb, map[i].key, map[i].val))
+			goto msg_full;
+
+	nla_nest_end(skb, stats);
+
+	return 0;
+msg_full:
+	nla_nest_cancel(skb, stats);
+
+	return -EMSGSIZE;
+}
+
+/* Caller should hold appropriate locks to protect the link */
+static int __tipc_nl_add_link(struct net *net, struct tipc_nl_msg *msg,
+			      struct tipc_link *link, int nlflags)
+{
+	int err;
+	void *hdr;
+	struct nlattr *attrs;
+	struct nlattr *prop;
+	struct tipc_net *tn = net_generic(net, tipc_net_id);
+
+	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
+			  nlflags, TIPC_NL_LINK_GET);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
+	if (!attrs)
+		goto msg_full;
+
+	if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, link->name))
+		goto attr_msg_full;
+	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_DEST,
+			tipc_cluster_mask(tn->own_addr)))
+		goto attr_msg_full;
+	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_MTU, link->mtu))
+		goto attr_msg_full;
+	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, link->next_in_no))
+		goto attr_msg_full;
+	if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, link->next_out_no))
+		goto attr_msg_full;
+
+	if (tipc_link_is_up(link))
+		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
+			goto attr_msg_full;
+	if (tipc_link_is_active(link))
+		if (nla_put_flag(msg->skb, TIPC_NLA_LINK_ACTIVE))
+			goto attr_msg_full;
+
+	prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
+	if (!prop)
+		goto attr_msg_full;
+	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
+		goto prop_msg_full;
+	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_TOL, link->tolerance))
+		goto prop_msg_full;
+	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN,
+			link->window))
+		goto prop_msg_full;
+	if (nla_put_u32(msg->skb, TIPC_NLA_PROP_PRIO, link->priority))
+		goto prop_msg_full;
+	nla_nest_end(msg->skb, prop);
+
+	err = __tipc_nl_add_stats(msg->skb, &link->stats);
+	if (err)
+		goto attr_msg_full;
+
+	nla_nest_end(msg->skb, attrs);
+	genlmsg_end(msg->skb, hdr);
+
+	return 0;
+
+prop_msg_full:
+	nla_nest_cancel(msg->skb, prop);
+attr_msg_full:
+	nla_nest_cancel(msg->skb, attrs);
+msg_full:
+	genlmsg_cancel(msg->skb, hdr);
+
+	return -EMSGSIZE;
+}
+
+/* Caller should hold node lock  */
+static int __tipc_nl_add_node_links(struct net *net, struct tipc_nl_msg *msg,
+				    struct tipc_node *node, u32 *prev_link)
+{
+	u32 i;
+	int err;
+
+	for (i = *prev_link; i < MAX_BEARERS; i++) {
+		*prev_link = i;
+
+		if (!node->links[i])
+			continue;
+
+		err = __tipc_nl_add_link(net, msg, node->links[i], NLM_F_MULTI);
+		if (err)
+			return err;
+	}
+	*prev_link = 0;
+
+	return 0;
+}
+
+int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct net *net = sock_net(skb->sk);
+	struct tipc_net *tn = net_generic(net, tipc_net_id);
+	struct tipc_node *node;
+	struct tipc_nl_msg msg;
+	u32 prev_node = cb->args[0];
+	u32 prev_link = cb->args[1];
+	int done = cb->args[2];
+	int err;
+
+	if (done)
+		return 0;
+
+	msg.skb = skb;
+	msg.portid = NETLINK_CB(cb->skb).portid;
+	msg.seq = cb->nlh->nlmsg_seq;
+
+	rcu_read_lock();
+	if (prev_node) {
+		node = tipc_node_find(net, prev_node);
+		if (!node) {
+			/* We never set seq or call nl_dump_check_consistent()
+			 * this means that setting prev_seq here will cause the
+			 * consistence check to fail in the netlink callback
+			 * handler. Resulting in the last NLMSG_DONE message
+			 * having the NLM_F_DUMP_INTR flag set.
+			 */
+			cb->prev_seq = 1;
+			goto out;
+		}
+		tipc_node_put(node);
+
+		list_for_each_entry_continue_rcu(node, &tn->node_list,
+						 list) {
+			tipc_node_lock(node);
+			err = __tipc_nl_add_node_links(net, &msg, node,
+						       &prev_link);
+			tipc_node_unlock(node);
+			if (err)
+				goto out;
+
+			prev_node = node->addr;
+		}
+	} else {
+		err = tipc_nl_add_bc_link(net, &msg);
+		if (err)
+			goto out;
+
+		list_for_each_entry_rcu(node, &tn->node_list, list) {
+			tipc_node_lock(node);
+			err = __tipc_nl_add_node_links(net, &msg, node,
+						       &prev_link);
+			tipc_node_unlock(node);
+			if (err)
+				goto out;
+
+			prev_node = node->addr;
+		}
+	}
+	done = 1;
+out:
+	rcu_read_unlock();
+
+	cb->args[0] = prev_node;
+	cb->args[1] = prev_link;
+	cb->args[2] = done;
+
+	return skb->len;
+}
+
+int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info)
+{
+	struct net *net = genl_info_net(info);
+	struct sk_buff *ans_skb;
+	struct tipc_nl_msg msg;
+	struct tipc_link *link;
+	struct tipc_node *node;
+	char *name;
+	int bearer_id;
+	int err;
+
+	if (!info->attrs[TIPC_NLA_LINK_NAME])
+		return -EINVAL;
+
+	name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]);
+	node = tipc_link_find_owner(net, name, &bearer_id);
+	if (!node)
+		return -EINVAL;
+
+	ans_skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!ans_skb)
+		return -ENOMEM;
+
+	msg.skb = ans_skb;
+	msg.portid = info->snd_portid;
+	msg.seq = info->snd_seq;
+
+	tipc_node_lock(node);
+	link = node->links[bearer_id];
+	if (!link) {
+		err = -EINVAL;
+		goto err_out;
+	}
+
+	err = __tipc_nl_add_link(net, &msg, link, 0);
+	if (err)
+		goto err_out;
+
+	tipc_node_unlock(node);
+
+	return genlmsg_reply(ans_skb, info);
+
+err_out:
+	tipc_node_unlock(node);
+	nlmsg_free(ans_skb);
+
+	return err;
+}
+
+int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info)
+{
+	int err;
+	char *link_name;
+	unsigned int bearer_id;
+	struct tipc_link *link;
+	struct tipc_node *node;
+	struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1];
+	struct net *net = sock_net(skb->sk);
+
+	if (!info->attrs[TIPC_NLA_LINK])
+		return -EINVAL;
+
+	err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX,
+			       info->attrs[TIPC_NLA_LINK],
+			       tipc_nl_link_policy);
+	if (err)
+		return err;
+
+	if (!attrs[TIPC_NLA_LINK_NAME])
+		return -EINVAL;
+
+	link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
+
+	if (strcmp(link_name, tipc_bclink_name) == 0) {
+		err = tipc_bclink_reset_stats(net);
+		if (err)
+			return err;
+		return 0;
+	}
+
+	node = tipc_link_find_owner(net, link_name, &bearer_id);
+	if (!node)
+		return -EINVAL;
+
+	tipc_node_lock(node);
+
+	link = node->links[bearer_id];
+	if (!link) {
+		tipc_node_unlock(node);
+		return -EINVAL;
+	}
+
+	link_reset_statistics(link);
+
+	tipc_node_unlock(node);
+
+	return 0;
+}