net/tipc/node.c - kernel/msm-4.9 - Gitiles

 /*
  * net/tipc/node.c: TIPC node management routines
  *
  * Copyright (c) 2000-2006, Ericsson AB
  * Copyright (c) 2005-2006, 2010-2011, 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 "config.h"
 #include "node.h"
 #include "name_distr.h"

 #define NODE_HTABLE_SIZE 512

 static void node_lost_contact(struct tipc_node *n_ptr);
 static void node_established_contact(struct tipc_node *n_ptr);

 static DEFINE_SPINLOCK(node_create_lock);

 static struct hlist_head node_htable[NODE_HTABLE_SIZE];
 LIST_HEAD(tipc_node_list);
 static u32 tipc_num_nodes;

 static atomic_t tipc_num_links = ATOMIC_INIT(0);

 /*
  * A trivial power-of-two bitmask technique is used for speed, since this
  * operation is done for every incoming TIPC packet. The number of hash table
  * entries has been chosen so that no hash chain exceeds 8 nodes and will
  * usually be much smaller (typically only a single node).
  */
 static unsigned int tipc_hashfn(u32 addr)
 {
 	return addr & (NODE_HTABLE_SIZE - 1);
 }

 /*
  * tipc_node_find - locate specified node object, if it exists
  */
 struct tipc_node *tipc_node_find(u32 addr)
 {
 	struct tipc_node *node;
 	struct hlist_node *pos;

 	if (unlikely(!in_own_cluster_exact(addr)))
 		return NULL;

 	hlist_for_each_entry(node, pos, &node_htable[tipc_hashfn(addr)], hash) {
 		if (node->addr == addr)
 			return node;
 	}
 	return NULL;
 }

 /**
  * tipc_node_create - create neighboring node
  *
  * Currently, this routine is called by neighbor discovery code, which holds
  * net_lock for reading only.  We must take node_create_lock to ensure a node
  * isn't created twice if two different bearers discover the node at the same
  * time.  (It would be preferable to switch to holding net_lock in write mode,
  * but this is a non-trivial change.)
  */
 struct tipc_node *tipc_node_create(u32 addr)
 {
 	struct tipc_node *n_ptr, *temp_node;

 	spin_lock_bh(&node_create_lock);

 	n_ptr = tipc_node_find(addr);
 	if (n_ptr) {
 		spin_unlock_bh(&node_create_lock);
 		return n_ptr;
 	}

 	n_ptr = kzalloc(sizeof(*n_ptr), GFP_ATOMIC);
 	if (!n_ptr) {
 		spin_unlock_bh(&node_create_lock);
 		pr_warn("Node creation failed, no memory\n");
 		return NULL;
 	}

 	n_ptr->addr = addr;
 	spin_lock_init(&n_ptr->lock);
 	INIT_HLIST_NODE(&n_ptr->hash);
 	INIT_LIST_HEAD(&n_ptr->list);
 	INIT_LIST_HEAD(&n_ptr->nsub);

 	hlist_add_head(&n_ptr->hash, &node_htable[tipc_hashfn(addr)]);

 	list_for_each_entry(temp_node, &tipc_node_list, list) {
 		if (n_ptr->addr < temp_node->addr)
 			break;
 	}
 	list_add_tail(&n_ptr->list, &temp_node->list);
 	n_ptr->block_setup = WAIT_PEER_DOWN;
 	n_ptr->signature = INVALID_NODE_SIG;

 	tipc_num_nodes++;

 	spin_unlock_bh(&node_create_lock);
 	return n_ptr;
 }

 void tipc_node_delete(struct tipc_node *n_ptr)
 {
 	list_del(&n_ptr->list);
 	hlist_del(&n_ptr->hash);
 	kfree(n_ptr);

 	tipc_num_nodes--;
 }

 /**
  * tipc_node_link_up - handle addition of link
  *
  * Link becomes active (alone or shared) or standby, depending on its priority.
  */
 void tipc_node_link_up(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 {
 	struct tipc_link **active = &n_ptr->active_links[0];

 	n_ptr->working_links++;

 	pr_info("Established link <%s> on network plane %c\n",
 		l_ptr->name, l_ptr->b_ptr->net_plane);

 	if (!active[0]) {
 		active[0] = active[1] = l_ptr;
 		node_established_contact(n_ptr);
 		return;
 	}
 	if (l_ptr->priority < active[0]->priority) {
 		pr_info("New link <%s> becomes standby\n", l_ptr->name);
 		return;
 	}
 	tipc_link_send_duplicate(active[0], l_ptr);
 	if (l_ptr->priority == active[0]->priority) {
 		active[0] = l_ptr;
 		return;
 	}
 	pr_info("Old link <%s> becomes standby\n", active[0]->name);
 	if (active[1] != active[0])
 		pr_info("Old link <%s> becomes standby\n", active[1]->name);
 	active[0] = active[1] = l_ptr;
 }

 /**
  * node_select_active_links - select active link
  */
 static void node_select_active_links(struct tipc_node *n_ptr)
 {
 	struct tipc_link **active = &n_ptr->active_links[0];
 	u32 i;
 	u32 highest_prio = 0;

 	active[0] = active[1] = NULL;

 	for (i = 0; i < MAX_BEARERS; i++) {
 		struct tipc_link *l_ptr = n_ptr->links[i];

 		if (!l_ptr || !tipc_link_is_up(l_ptr) ||
 		    (l_ptr->priority < highest_prio))
 			continue;

 		if (l_ptr->priority > highest_prio) {
 			highest_prio = l_ptr->priority;
 			active[0] = active[1] = l_ptr;
 		} else {
 			active[1] = l_ptr;
 		}
 	}
 }

 /**
  * tipc_node_link_down - handle loss of link
  */
 void tipc_node_link_down(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 {
 	struct tipc_link **active;

 	n_ptr->working_links--;

 	if (!tipc_link_is_active(l_ptr)) {
 		pr_info("Lost standby link <%s> on network plane %c\n",
 			l_ptr->name, l_ptr->b_ptr->net_plane);
 		return;
 	}
 	pr_info("Lost link <%s> on network plane %c\n",
 		l_ptr->name, l_ptr->b_ptr->net_plane);

 	active = &n_ptr->active_links[0];
 	if (active[0] == l_ptr)
 		active[0] = active[1];
 	if (active[1] == l_ptr)
 		active[1] = active[0];
 	if (active[0] == l_ptr)
 		node_select_active_links(n_ptr);
 	if (tipc_node_is_up(n_ptr))
 		tipc_link_changeover(l_ptr);
 	else
 		node_lost_contact(n_ptr);
 }

 int tipc_node_active_links(struct tipc_node *n_ptr)
 {
 	return n_ptr->active_links[0] != NULL;
 }

 int tipc_node_redundant_links(struct tipc_node *n_ptr)
 {
 	return n_ptr->working_links > 1;
 }

 int tipc_node_is_up(struct tipc_node *n_ptr)
 {
 	return tipc_node_active_links(n_ptr);
 }

 void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 {
 	n_ptr->links[l_ptr->b_ptr->identity] = l_ptr;
 	atomic_inc(&tipc_num_links);
 	n_ptr->link_cnt++;
 }

 void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
 {
 	n_ptr->links[l_ptr->b_ptr->identity] = NULL;
 	atomic_dec(&tipc_num_links);
 	n_ptr->link_cnt--;
 }

 static void node_established_contact(struct tipc_node *n_ptr)
 {
 	tipc_k_signal((Handler)tipc_named_node_up, n_ptr->addr);

 	if (n_ptr->bclink.supportable) {
 		n_ptr->bclink.acked = tipc_bclink_get_last_sent();
 		tipc_bclink_add_node(n_ptr->addr);
 		n_ptr->bclink.supported = 1;
 	}
 }

 static void node_name_purge_complete(unsigned long node_addr)
 {
 	struct tipc_node *n_ptr;

 	read_lock_bh(&tipc_net_lock);
 	n_ptr = tipc_node_find(node_addr);
 	if (n_ptr) {
 		tipc_node_lock(n_ptr);
 		n_ptr->block_setup &= ~WAIT_NAMES_GONE;
 		tipc_node_unlock(n_ptr);
 	}
 	read_unlock_bh(&tipc_net_lock);
 }

 static void node_lost_contact(struct tipc_node *n_ptr)
 {
 	char addr_string[16];
 	u32 i;

 	pr_info("Lost contact with %s\n",
 		tipc_addr_string_fill(addr_string, n_ptr->addr));

 	/* Flush broadcast link info associated with lost node */
 	if (n_ptr->bclink.supported) {
 		while (n_ptr->bclink.deferred_head) {
 			struct sk_buff *buf = n_ptr->bclink.deferred_head;
 			n_ptr->bclink.deferred_head = buf->next;
 			kfree_skb(buf);
 		}
 		n_ptr->bclink.deferred_size = 0;

 		if (n_ptr->bclink.defragm) {
 			kfree_skb(n_ptr->bclink.defragm);
 			n_ptr->bclink.defragm = NULL;
 		}

 		tipc_bclink_remove_node(n_ptr->addr);
 		tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);

 		n_ptr->bclink.supported = 0;
 	}

 	/* Abort link changeover */
 	for (i = 0; i < MAX_BEARERS; i++) {
 		struct tipc_link *l_ptr = n_ptr->links[i];
 		if (!l_ptr)
 			continue;
 		l_ptr->reset_checkpoint = l_ptr->next_in_no;
 		l_ptr->exp_msg_count = 0;
 		tipc_link_reset_fragments(l_ptr);
 	}

 	/* Notify subscribers */
 	tipc_nodesub_notify(n_ptr);

 	/* Prevent re-contact with node until cleanup is done */
 	n_ptr->block_setup = WAIT_PEER_DOWN | WAIT_NAMES_GONE;
 	tipc_k_signal((Handler)node_name_purge_complete, n_ptr->addr);
 }

 struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space)
 {
 	u32 domain;
 	struct sk_buff *buf;
 	struct tipc_node *n_ptr;
 	struct tipc_node_info node_info;
 	u32 payload_size;

 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

 	domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
 	if (!tipc_addr_domain_valid(domain))
 		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
 						   " (network address)");

 	read_lock_bh(&tipc_net_lock);
 	if (!tipc_num_nodes) {
 		read_unlock_bh(&tipc_net_lock);
 		return tipc_cfg_reply_none();
 	}

 	/* For now, get space for all other nodes */
 	payload_size = TLV_SPACE(sizeof(node_info)) * tipc_num_nodes;
 	if (payload_size > 32768u) {
 		read_unlock_bh(&tipc_net_lock);
 		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
 						   " (too many nodes)");
 	}
 	buf = tipc_cfg_reply_alloc(payload_size);
 	if (!buf) {
 		read_unlock_bh(&tipc_net_lock);
 		return NULL;
 	}

 	/* Add TLVs for all nodes in scope */
 	list_for_each_entry(n_ptr, &tipc_node_list, list) {
 		if (!tipc_in_scope(domain, n_ptr->addr))
 			continue;
 		node_info.addr = htonl(n_ptr->addr);
 		node_info.up = htonl(tipc_node_is_up(n_ptr));
 		tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
 				    &node_info, sizeof(node_info));
 	}

 	read_unlock_bh(&tipc_net_lock);
 	return buf;
 }

 struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
 {
 	u32 domain;
 	struct sk_buff *buf;
 	struct tipc_node *n_ptr;
 	struct tipc_link_info link_info;
 	u32 payload_size;

 	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
 		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

 	domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
 	if (!tipc_addr_domain_valid(domain))
 		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
 						   " (network address)");

 	if (!tipc_own_addr)
 		return tipc_cfg_reply_none();

 	read_lock_bh(&tipc_net_lock);

 	/* Get space for all unicast links + broadcast link */
 	payload_size = TLV_SPACE(sizeof(link_info)) *
 		(atomic_read(&tipc_num_links) + 1);
 	if (payload_size > 32768u) {
 		read_unlock_bh(&tipc_net_lock);
 		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
 						   " (too many links)");
 	}
 	buf = tipc_cfg_reply_alloc(payload_size);
 	if (!buf) {
 		read_unlock_bh(&tipc_net_lock);
 		return NULL;
 	}

 	/* Add TLV for broadcast link */
 	link_info.dest = htonl(tipc_cluster_mask(tipc_own_addr));
 	link_info.up = htonl(1);
 	strlcpy(link_info.str, tipc_bclink_name, TIPC_MAX_LINK_NAME);
 	tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));

 	/* Add TLVs for any other links in scope */
 	list_for_each_entry(n_ptr, &tipc_node_list, list) {
 		u32 i;

 		if (!tipc_in_scope(domain, n_ptr->addr))
 			continue;
 		tipc_node_lock(n_ptr);
 		for (i = 0; i < MAX_BEARERS; i++) {
 			if (!n_ptr->links[i])
 				continue;
 			link_info.dest = htonl(n_ptr->addr);
 			link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
 			strcpy(link_info.str, n_ptr->links[i]->name);
 			tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
 					    &link_info, sizeof(link_info));
 		}
 		tipc_node_unlock(n_ptr);
 	}

 	read_unlock_bh(&tipc_net_lock);
 	return buf;
 }
	/*
	* net/tipc/node.c: TIPC node management routines
	*
	* Copyright (c) 2000-2006, Ericsson AB
	* Copyright (c) 2005-2006, 2010-2011, 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 "config.h"
	#include "node.h"
	#include "name_distr.h"

	#define NODE_HTABLE_SIZE 512

	static void node_lost_contact(struct tipc_node *n_ptr);
	static void node_established_contact(struct tipc_node *n_ptr);

	static DEFINE_SPINLOCK(node_create_lock);

	static struct hlist_head node_htable[NODE_HTABLE_SIZE];
	LIST_HEAD(tipc_node_list);
	static u32 tipc_num_nodes;

	static atomic_t tipc_num_links = ATOMIC_INIT(0);

	/*
	* A trivial power-of-two bitmask technique is used for speed, since this
	* operation is done for every incoming TIPC packet. The number of hash table
	* entries has been chosen so that no hash chain exceeds 8 nodes and will
	* usually be much smaller (typically only a single node).
	*/
	static unsigned int tipc_hashfn(u32 addr)
	{
	return addr & (NODE_HTABLE_SIZE - 1);
	}

	/*
	* tipc_node_find - locate specified node object, if it exists
	*/
	struct tipc_node *tipc_node_find(u32 addr)
	{
	struct tipc_node *node;
	struct hlist_node *pos;

	if (unlikely(!in_own_cluster_exact(addr)))
	return NULL;

	hlist_for_each_entry(node, pos, &node_htable[tipc_hashfn(addr)], hash) {
	if (node->addr == addr)
	return node;
	}
	return NULL;
	}

	/**
	* tipc_node_create - create neighboring node
	*
	* Currently, this routine is called by neighbor discovery code, which holds
	* net_lock for reading only. We must take node_create_lock to ensure a node
	* isn't created twice if two different bearers discover the node at the same
	* time. (It would be preferable to switch to holding net_lock in write mode,
	* but this is a non-trivial change.)
	*/
	struct tipc_node *tipc_node_create(u32 addr)
	{
	struct tipc_node n_ptr, temp_node;

	spin_lock_bh(&node_create_lock);

	n_ptr = tipc_node_find(addr);
	if (n_ptr) {
	spin_unlock_bh(&node_create_lock);
	return n_ptr;
	}

	n_ptr = kzalloc(sizeof(*n_ptr), GFP_ATOMIC);
	if (!n_ptr) {
	spin_unlock_bh(&node_create_lock);
	pr_warn("Node creation failed, no memory\n");
	return NULL;
	}

	n_ptr->addr = addr;
	spin_lock_init(&n_ptr->lock);
	INIT_HLIST_NODE(&n_ptr->hash);
	INIT_LIST_HEAD(&n_ptr->list);
	INIT_LIST_HEAD(&n_ptr->nsub);

	hlist_add_head(&n_ptr->hash, &node_htable[tipc_hashfn(addr)]);

	list_for_each_entry(temp_node, &tipc_node_list, list) {
	if (n_ptr->addr < temp_node->addr)
	break;
	}
	list_add_tail(&n_ptr->list, &temp_node->list);
	n_ptr->block_setup = WAIT_PEER_DOWN;
	n_ptr->signature = INVALID_NODE_SIG;

	tipc_num_nodes++;

	spin_unlock_bh(&node_create_lock);
	return n_ptr;
	}

	void tipc_node_delete(struct tipc_node *n_ptr)
	{
	list_del(&n_ptr->list);
	hlist_del(&n_ptr->hash);
	kfree(n_ptr);

	tipc_num_nodes--;
	}

	/**
	* tipc_node_link_up - handle addition of link
	*
	* Link becomes active (alone or shared) or standby, depending on its priority.
	*/
	void tipc_node_link_up(struct tipc_node n_ptr, struct tipc_link l_ptr)
	{
	struct tipc_link **active = &n_ptr->active_links[0];

	n_ptr->working_links++;

	pr_info("Established link <%s> on network plane %c\n",
	l_ptr->name, l_ptr->b_ptr->net_plane);

	if (!active[0]) {
	active[0] = active[1] = l_ptr;
	node_established_contact(n_ptr);
	return;
	}
	if (l_ptr->priority < active[0]->priority) {
	pr_info("New link <%s> becomes standby\n", l_ptr->name);
	return;
	}
	tipc_link_send_duplicate(active[0], l_ptr);
	if (l_ptr->priority == active[0]->priority) {
	active[0] = l_ptr;
	return;
	}
	pr_info("Old link <%s> becomes standby\n", active[0]->name);
	if (active[1] != active[0])
	pr_info("Old link <%s> becomes standby\n", active[1]->name);
	active[0] = active[1] = l_ptr;
	}

	/**
	* node_select_active_links - select active link
	*/
	static void node_select_active_links(struct tipc_node *n_ptr)
	{
	struct tipc_link **active = &n_ptr->active_links[0];
	u32 i;
	u32 highest_prio = 0;

	active[0] = active[1] = NULL;

	for (i = 0; i < MAX_BEARERS; i++) {
	struct tipc_link *l_ptr = n_ptr->links[i];

	if (!l_ptr \|\| !tipc_link_is_up(l_ptr) \|\|
	(l_ptr->priority < highest_prio))
	continue;

	if (l_ptr->priority > highest_prio) {
	highest_prio = l_ptr->priority;
	active[0] = active[1] = l_ptr;
	} else {
	active[1] = l_ptr;
	}
	}
	}

	/**
	* tipc_node_link_down - handle loss of link
	*/
	void tipc_node_link_down(struct tipc_node n_ptr, struct tipc_link l_ptr)
	{
	struct tipc_link **active;

	n_ptr->working_links--;

	if (!tipc_link_is_active(l_ptr)) {
	pr_info("Lost standby link <%s> on network plane %c\n",
	l_ptr->name, l_ptr->b_ptr->net_plane);
	return;
	}
	pr_info("Lost link <%s> on network plane %c\n",
	l_ptr->name, l_ptr->b_ptr->net_plane);

	active = &n_ptr->active_links[0];
	if (active[0] == l_ptr)
	active[0] = active[1];
	if (active[1] == l_ptr)
	active[1] = active[0];
	if (active[0] == l_ptr)
	node_select_active_links(n_ptr);
	if (tipc_node_is_up(n_ptr))
	tipc_link_changeover(l_ptr);
	else
	node_lost_contact(n_ptr);
	}

	int tipc_node_active_links(struct tipc_node *n_ptr)
	{
	return n_ptr->active_links[0] != NULL;
	}

	int tipc_node_redundant_links(struct tipc_node *n_ptr)
	{
	return n_ptr->working_links > 1;
	}

	int tipc_node_is_up(struct tipc_node *n_ptr)
	{
	return tipc_node_active_links(n_ptr);
	}

	void tipc_node_attach_link(struct tipc_node n_ptr, struct tipc_link l_ptr)
	{
	n_ptr->links[l_ptr->b_ptr->identity] = l_ptr;
	atomic_inc(&tipc_num_links);
	n_ptr->link_cnt++;
	}

	void tipc_node_detach_link(struct tipc_node n_ptr, struct tipc_link l_ptr)
	{
	n_ptr->links[l_ptr->b_ptr->identity] = NULL;
	atomic_dec(&tipc_num_links);
	n_ptr->link_cnt--;
	}

	static void node_established_contact(struct tipc_node *n_ptr)
	{
	tipc_k_signal((Handler)tipc_named_node_up, n_ptr->addr);

	if (n_ptr->bclink.supportable) {
	n_ptr->bclink.acked = tipc_bclink_get_last_sent();
	tipc_bclink_add_node(n_ptr->addr);
	n_ptr->bclink.supported = 1;
	}
	}

	static void node_name_purge_complete(unsigned long node_addr)
	{
	struct tipc_node *n_ptr;

	read_lock_bh(&tipc_net_lock);
	n_ptr = tipc_node_find(node_addr);
	if (n_ptr) {
	tipc_node_lock(n_ptr);
	n_ptr->block_setup &= ~WAIT_NAMES_GONE;
	tipc_node_unlock(n_ptr);
	}
	read_unlock_bh(&tipc_net_lock);
	}

	static void node_lost_contact(struct tipc_node *n_ptr)
	{
	char addr_string[16];
	u32 i;

	pr_info("Lost contact with %s\n",
	tipc_addr_string_fill(addr_string, n_ptr->addr));

	/* Flush broadcast link info associated with lost node */
	if (n_ptr->bclink.supported) {
	while (n_ptr->bclink.deferred_head) {
	struct sk_buff *buf = n_ptr->bclink.deferred_head;
	n_ptr->bclink.deferred_head = buf->next;
	kfree_skb(buf);
	}
	n_ptr->bclink.deferred_size = 0;

	if (n_ptr->bclink.defragm) {
	kfree_skb(n_ptr->bclink.defragm);
	n_ptr->bclink.defragm = NULL;
	}

	tipc_bclink_remove_node(n_ptr->addr);
	tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);

	n_ptr->bclink.supported = 0;
	}

	/* Abort link changeover */
	for (i = 0; i < MAX_BEARERS; i++) {
	struct tipc_link *l_ptr = n_ptr->links[i];
	if (!l_ptr)
	continue;
	l_ptr->reset_checkpoint = l_ptr->next_in_no;
	l_ptr->exp_msg_count = 0;
	tipc_link_reset_fragments(l_ptr);
	}

	/* Notify subscribers */
	tipc_nodesub_notify(n_ptr);

	/* Prevent re-contact with node until cleanup is done */
	n_ptr->block_setup = WAIT_PEER_DOWN \| WAIT_NAMES_GONE;
	tipc_k_signal((Handler)node_name_purge_complete, n_ptr->addr);
	}

	struct sk_buff tipc_node_get_nodes(const void req_tlv_area, int req_tlv_space)
	{
	u32 domain;
	struct sk_buff *buf;
	struct tipc_node *n_ptr;
	struct tipc_node_info node_info;
	u32 payload_size;

	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
	return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

	domain = ntohl((__be32 )TLV_DATA(req_tlv_area));
	if (!tipc_addr_domain_valid(domain))
	return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
	" (network address)");

	read_lock_bh(&tipc_net_lock);
	if (!tipc_num_nodes) {
	read_unlock_bh(&tipc_net_lock);
	return tipc_cfg_reply_none();
	}

	/* For now, get space for all other nodes */
	payload_size = TLV_SPACE(sizeof(node_info)) * tipc_num_nodes;
	if (payload_size > 32768u) {
	read_unlock_bh(&tipc_net_lock);
	return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
	" (too many nodes)");
	}
	buf = tipc_cfg_reply_alloc(payload_size);
	if (!buf) {
	read_unlock_bh(&tipc_net_lock);
	return NULL;
	}

	/* Add TLVs for all nodes in scope */
	list_for_each_entry(n_ptr, &tipc_node_list, list) {
	if (!tipc_in_scope(domain, n_ptr->addr))
	continue;
	node_info.addr = htonl(n_ptr->addr);
	node_info.up = htonl(tipc_node_is_up(n_ptr));
	tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
	&node_info, sizeof(node_info));
	}

	read_unlock_bh(&tipc_net_lock);
	return buf;
	}

	struct sk_buff tipc_node_get_links(const void req_tlv_area, int req_tlv_space)
	{
	u32 domain;
	struct sk_buff *buf;
	struct tipc_node *n_ptr;
	struct tipc_link_info link_info;
	u32 payload_size;

	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
	return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

	domain = ntohl((__be32 )TLV_DATA(req_tlv_area));
	if (!tipc_addr_domain_valid(domain))
	return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
	" (network address)");

	if (!tipc_own_addr)
	return tipc_cfg_reply_none();

	read_lock_bh(&tipc_net_lock);

	/* Get space for all unicast links + broadcast link */
	payload_size = TLV_SPACE(sizeof(link_info)) *
	(atomic_read(&tipc_num_links) + 1);
	if (payload_size > 32768u) {
	read_unlock_bh(&tipc_net_lock);
	return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
	" (too many links)");
	}
	buf = tipc_cfg_reply_alloc(payload_size);
	if (!buf) {
	read_unlock_bh(&tipc_net_lock);
	return NULL;
	}

	/* Add TLV for broadcast link */
	link_info.dest = htonl(tipc_cluster_mask(tipc_own_addr));
	link_info.up = htonl(1);
	strlcpy(link_info.str, tipc_bclink_name, TIPC_MAX_LINK_NAME);
	tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));

	/* Add TLVs for any other links in scope */
	list_for_each_entry(n_ptr, &tipc_node_list, list) {
	u32 i;

	if (!tipc_in_scope(domain, n_ptr->addr))
	continue;
	tipc_node_lock(n_ptr);
	for (i = 0; i < MAX_BEARERS; i++) {
	if (!n_ptr->links[i])
	continue;
	link_info.dest = htonl(n_ptr->addr);
	link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
	strcpy(link_info.str, n_ptr->links[i]->name);
	tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
	&link_info, sizeof(link_info));
	}
	tipc_node_unlock(n_ptr);
	}

	read_unlock_bh(&tipc_net_lock);
	return buf;
	}