net/tipc/name_distr.c - kernel/bruno - Git at Google

 /*
  * net/tipc/name_distr.c: TIPC name distribution code
  *
  * Copyright (c) 2000-2006, 2014, Ericsson AB
  * Copyright (c) 2005, 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 "link.h"
 #include "name_distr.h"

 int sysctl_tipc_named_timeout __read_mostly = 2000;

 /**
  * struct tipc_dist_queue - queue holding deferred name table updates
  */
 static struct list_head tipc_dist_queue = LIST_HEAD_INIT(tipc_dist_queue);

 struct distr_queue_item {
 	struct distr_item i;
 	u32 dtype;
 	u32 node;
 	unsigned long expires;
 	struct list_head next;
 };

 /**
  * publ_to_item - add publication info to a publication message
  */
 static void publ_to_item(struct distr_item *i, struct publication *p)
 {
 	i->type = htonl(p->type);
 	i->lower = htonl(p->lower);
 	i->upper = htonl(p->upper);
 	i->ref = htonl(p->ref);
 	i->key = htonl(p->key);
 }

 /**
  * named_prepare_buf - allocate & initialize a publication message
  */
 static struct sk_buff *named_prepare_buf(u32 type, u32 size, u32 dest)
 {
 	struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE + size);
 	struct tipc_msg *msg;

 	if (buf != NULL) {
 		msg = buf_msg(buf);
 		tipc_msg_init(msg, NAME_DISTRIBUTOR, type, INT_H_SIZE, dest);
 		msg_set_size(msg, INT_H_SIZE + size);
 	}
 	return buf;
 }

 void named_cluster_distribute(struct sk_buff *skb)
 {
 	struct sk_buff *oskb;
 	struct tipc_node *node;
 	u32 dnode;

 	rcu_read_lock();
 	list_for_each_entry_rcu(node, &tipc_node_list, list) {
 		dnode = node->addr;
 		if (in_own_node(dnode))
 			continue;
 		if (!tipc_node_active_links(node))
 			continue;
 		oskb = skb_copy(skb, GFP_ATOMIC);
 		if (!oskb)
 			break;
 		msg_set_destnode(buf_msg(oskb), dnode);
 		tipc_link_xmit_skb(oskb, dnode, dnode);
 	}
 	rcu_read_unlock();

 	kfree_skb(skb);
 }

 /**
  * tipc_named_publish - tell other nodes about a new publication by this node
  */
 struct sk_buff *tipc_named_publish(struct publication *publ)
 {
 	struct sk_buff *buf;
 	struct distr_item *item;

 	list_add_tail_rcu(&publ->local_list,
 			  &tipc_nametbl->publ_list[publ->scope]);

 	if (publ->scope == TIPC_NODE_SCOPE)
 		return NULL;

 	buf = named_prepare_buf(PUBLICATION, ITEM_SIZE, 0);
 	if (!buf) {
 		pr_warn("Publication distribution failure\n");
 		return NULL;
 	}

 	item = (struct distr_item *)msg_data(buf_msg(buf));
 	publ_to_item(item, publ);
 	return buf;
 }

 /**
  * tipc_named_withdraw - tell other nodes about a withdrawn publication by this node
  */
 struct sk_buff *tipc_named_withdraw(struct publication *publ)
 {
 	struct sk_buff *buf;
 	struct distr_item *item;

 	list_del(&publ->local_list);

 	if (publ->scope == TIPC_NODE_SCOPE)
 		return NULL;

 	buf = named_prepare_buf(WITHDRAWAL, ITEM_SIZE, 0);
 	if (!buf) {
 		pr_warn("Withdrawal distribution failure\n");
 		return NULL;
 	}

 	item = (struct distr_item *)msg_data(buf_msg(buf));
 	publ_to_item(item, publ);
 	return buf;
 }

 /**
  * named_distribute - prepare name info for bulk distribution to another node
  * @list: list of messages (buffers) to be returned from this function
  * @dnode: node to be updated
  * @pls: linked list of publication items to be packed into buffer chain
  */
 static void named_distribute(struct sk_buff_head *list, u32 dnode,
 			     struct list_head *pls)
 {
 	struct publication *publ;
 	struct sk_buff *skb = NULL;
 	struct distr_item *item = NULL;
 	uint msg_dsz = (tipc_node_get_mtu(dnode, 0) / ITEM_SIZE) * ITEM_SIZE;
 	uint msg_rem = msg_dsz;

 	list_for_each_entry(publ, pls, local_list) {
 		/* Prepare next buffer: */
 		if (!skb) {
 			skb = named_prepare_buf(PUBLICATION, msg_rem, dnode);
 			if (!skb) {
 				pr_warn("Bulk publication failure\n");
 				return;
 			}
 			item = (struct distr_item *)msg_data(buf_msg(skb));
 		}

 		/* Pack publication into message: */
 		publ_to_item(item, publ);
 		item++;
 		msg_rem -= ITEM_SIZE;

 		/* Append full buffer to list: */
 		if (!msg_rem) {
 			__skb_queue_tail(list, skb);
 			skb = NULL;
 			msg_rem = msg_dsz;
 		}
 	}
 	if (skb) {
 		msg_set_size(buf_msg(skb), INT_H_SIZE + (msg_dsz - msg_rem));
 		skb_trim(skb, INT_H_SIZE + (msg_dsz - msg_rem));
 		__skb_queue_tail(list, skb);
 	}
 }

 /**
  * tipc_named_node_up - tell specified node about all publications by this node
  */
 void tipc_named_node_up(u32 dnode)
 {
 	struct sk_buff_head head;

 	__skb_queue_head_init(&head);

 	rcu_read_lock();
 	named_distribute(&head, dnode,
 			 &tipc_nametbl->publ_list[TIPC_CLUSTER_SCOPE]);
 	named_distribute(&head, dnode,
 			 &tipc_nametbl->publ_list[TIPC_ZONE_SCOPE]);
 	rcu_read_unlock();

 	tipc_link_xmit(&head, dnode, dnode);
 }

 static void tipc_publ_subscribe(struct publication *publ, u32 addr)
 {
 	struct tipc_node *node;

 	if (in_own_node(addr))
 		return;

 	node = tipc_node_find(addr);
 	if (!node) {
 		pr_warn("Node subscription rejected, unknown node 0x%x\n",
 			addr);
 		return;
 	}

 	tipc_node_lock(node);
 	list_add_tail(&publ->nodesub_list, &node->publ_list);
 	tipc_node_unlock(node);
 }

 static void tipc_publ_unsubscribe(struct publication *publ, u32 addr)
 {
 	struct tipc_node *node;

 	node = tipc_node_find(addr);
 	if (!node)
 		return;

 	tipc_node_lock(node);
 	list_del_init(&publ->nodesub_list);
 	tipc_node_unlock(node);
 }

 /**
  * tipc_publ_purge - remove publication associated with a failed node
  *
  * Invoked for each publication issued by a newly failed node.
  * Removes publication structure from name table & deletes it.
  */
 static void tipc_publ_purge(struct publication *publ, u32 addr)
 {
 	struct publication *p;

 	spin_lock_bh(&tipc_nametbl_lock);
 	p = tipc_nametbl_remove_publ(publ->type, publ->lower,
 				     publ->node, publ->ref, publ->key);
 	if (p)
 		tipc_publ_unsubscribe(p, addr);
 	spin_unlock_bh(&tipc_nametbl_lock);

 	if (p != publ) {
 		pr_err("Unable to remove publication from failed node\n"
 		       " (type=%u, lower=%u, node=0x%x, ref=%u, key=%u)\n",
 		       publ->type, publ->lower, publ->node, publ->ref,
 		       publ->key);
 	}

 	kfree_rcu(p, rcu);
 }

 void tipc_publ_notify(struct list_head *nsub_list, u32 addr)
 {
 	struct publication *publ, *tmp;

 	list_for_each_entry_safe(publ, tmp, nsub_list, nodesub_list)
 		tipc_publ_purge(publ, addr);
 }

 /**
  * tipc_update_nametbl - try to process a nametable update and notify
  *			 subscribers
  *
  * tipc_nametbl_lock must be held.
  * Returns the publication item if successful, otherwise NULL.
  */
 static bool tipc_update_nametbl(struct distr_item *i, u32 node, u32 dtype)
 {
 	struct publication *publ = NULL;

 	if (dtype == PUBLICATION) {
 		publ = tipc_nametbl_insert_publ(ntohl(i->type), ntohl(i->lower),
 						ntohl(i->upper),
 						TIPC_CLUSTER_SCOPE, node,
 						ntohl(i->ref), ntohl(i->key));
 		if (publ) {
 			tipc_publ_subscribe(publ, node);
 			return true;
 		}
 	} else if (dtype == WITHDRAWAL) {
 		publ = tipc_nametbl_remove_publ(ntohl(i->type), ntohl(i->lower),
 						node, ntohl(i->ref),
 						ntohl(i->key));
 		if (publ) {
 			tipc_publ_unsubscribe(publ, node);
 			kfree_rcu(publ, rcu);
 			return true;
 		}
 	} else {
 		pr_warn("Unrecognized name table message received\n");
 	}
 	return false;
 }

 /**
  * tipc_named_add_backlog - add a failed name table update to the backlog
  *
  */
 static void tipc_named_add_backlog(struct distr_item *i, u32 type, u32 node)
 {
 	struct distr_queue_item *e;
 	unsigned long now = get_jiffies_64();

 	e = kzalloc(sizeof(*e), GFP_ATOMIC);
 	if (!e)
 		return;
 	e->dtype = type;
 	e->node = node;
 	e->expires = now + msecs_to_jiffies(sysctl_tipc_named_timeout);
 	memcpy(e, i, sizeof(*i));
 	list_add_tail(&e->next, &tipc_dist_queue);
 }

 /**
  * tipc_named_process_backlog - try to process any pending name table updates
  * from the network.
  */
 void tipc_named_process_backlog(void)
 {
 	struct distr_queue_item *e, *tmp;
 	char addr[16];
 	unsigned long now = get_jiffies_64();

 	list_for_each_entry_safe(e, tmp, &tipc_dist_queue, next) {
 		if (time_after(e->expires, now)) {
 			if (!tipc_update_nametbl(&e->i, e->node, e->dtype))
 				continue;
 		} else {
 			tipc_addr_string_fill(addr, e->node);
 			pr_warn_ratelimited("Dropping name table update (%d) of {%u, %u, %u} from %s key=%u\n",
 					    e->dtype, ntohl(e->i.type),
 					    ntohl(e->i.lower),
 					    ntohl(e->i.upper),
 					    addr, ntohl(e->i.key));
 		}
 		list_del(&e->next);
 		kfree(e);
 	}
 }

 /**
  * tipc_named_rcv - process name table update message sent by another node
  */
 void tipc_named_rcv(struct sk_buff *buf)
 {
 	struct tipc_msg *msg = buf_msg(buf);
 	struct distr_item *item = (struct distr_item *)msg_data(msg);
 	u32 count = msg_data_sz(msg) / ITEM_SIZE;
 	u32 node = msg_orignode(msg);

 	spin_lock_bh(&tipc_nametbl_lock);
 	while (count--) {
 		if (!tipc_update_nametbl(item, node, msg_type(msg)))
 			tipc_named_add_backlog(item, msg_type(msg), node);
 		item++;
 	}
 	tipc_named_process_backlog();
 	spin_unlock_bh(&tipc_nametbl_lock);
 	kfree_skb(buf);
 }

 /**
  * tipc_named_reinit - re-initialize local publications
  *
  * This routine is called whenever TIPC networking is enabled.
  * All name table entries published by this node are updated to reflect
  * the node's new network address.
  */
 void tipc_named_reinit(void)
 {
 	struct publication *publ;
 	int scope;

 	spin_lock_bh(&tipc_nametbl_lock);

 	for (scope = TIPC_ZONE_SCOPE; scope <= TIPC_NODE_SCOPE; scope++)
 		list_for_each_entry_rcu(publ, &tipc_nametbl->publ_list[scope],
 					local_list)
 			publ->node = tipc_own_addr;

 	spin_unlock_bh(&tipc_nametbl_lock);
 }
	/*
	* net/tipc/name_distr.c: TIPC name distribution code
	*
	* Copyright (c) 2000-2006, 2014, Ericsson AB
	* Copyright (c) 2005, 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 "link.h"
	#include "name_distr.h"

	int sysctl_tipc_named_timeout __read_mostly = 2000;

	/**
	* struct tipc_dist_queue - queue holding deferred name table updates
	*/
	static struct list_head tipc_dist_queue = LIST_HEAD_INIT(tipc_dist_queue);

	struct distr_queue_item {
	struct distr_item i;
	u32 dtype;
	u32 node;
	unsigned long expires;
	struct list_head next;
	};

	/**
	* publ_to_item - add publication info to a publication message
	*/
	static void publ_to_item(struct distr_item i, struct publication p)
	{
	i->type = htonl(p->type);
	i->lower = htonl(p->lower);
	i->upper = htonl(p->upper);
	i->ref = htonl(p->ref);
	i->key = htonl(p->key);
	}

	/**
	* named_prepare_buf - allocate & initialize a publication message
	*/
	static struct sk_buff *named_prepare_buf(u32 type, u32 size, u32 dest)
	{
	struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE + size);
	struct tipc_msg *msg;

	if (buf != NULL) {
	msg = buf_msg(buf);
	tipc_msg_init(msg, NAME_DISTRIBUTOR, type, INT_H_SIZE, dest);
	msg_set_size(msg, INT_H_SIZE + size);
	}
	return buf;
	}

	void named_cluster_distribute(struct sk_buff *skb)
	{
	struct sk_buff *oskb;
	struct tipc_node *node;
	u32 dnode;

	rcu_read_lock();
	list_for_each_entry_rcu(node, &tipc_node_list, list) {
	dnode = node->addr;
	if (in_own_node(dnode))
	continue;
	if (!tipc_node_active_links(node))
	continue;
	oskb = skb_copy(skb, GFP_ATOMIC);
	if (!oskb)
	break;
	msg_set_destnode(buf_msg(oskb), dnode);
	tipc_link_xmit_skb(oskb, dnode, dnode);
	}
	rcu_read_unlock();

	kfree_skb(skb);
	}

	/**
	* tipc_named_publish - tell other nodes about a new publication by this node
	*/
	struct sk_buff tipc_named_publish(struct publication publ)
	{
	struct sk_buff *buf;
	struct distr_item *item;

	list_add_tail_rcu(&publ->local_list,
	&tipc_nametbl->publ_list[publ->scope]);

	if (publ->scope == TIPC_NODE_SCOPE)
	return NULL;

	buf = named_prepare_buf(PUBLICATION, ITEM_SIZE, 0);
	if (!buf) {
	pr_warn("Publication distribution failure\n");
	return NULL;
	}

	item = (struct distr_item *)msg_data(buf_msg(buf));
	publ_to_item(item, publ);
	return buf;
	}

	/**
	* tipc_named_withdraw - tell other nodes about a withdrawn publication by this node
	*/
	struct sk_buff tipc_named_withdraw(struct publication publ)
	{
	struct sk_buff *buf;
	struct distr_item *item;

	list_del(&publ->local_list);

	if (publ->scope == TIPC_NODE_SCOPE)
	return NULL;

	buf = named_prepare_buf(WITHDRAWAL, ITEM_SIZE, 0);
	if (!buf) {
	pr_warn("Withdrawal distribution failure\n");
	return NULL;
	}

	item = (struct distr_item *)msg_data(buf_msg(buf));
	publ_to_item(item, publ);
	return buf;
	}

	/**
	* named_distribute - prepare name info for bulk distribution to another node
	* @list: list of messages (buffers) to be returned from this function
	* @dnode: node to be updated
	* @pls: linked list of publication items to be packed into buffer chain
	*/
	static void named_distribute(struct sk_buff_head *list, u32 dnode,
	struct list_head *pls)
	{
	struct publication *publ;
	struct sk_buff *skb = NULL;
	struct distr_item *item = NULL;
	uint msg_dsz = (tipc_node_get_mtu(dnode, 0) / ITEM_SIZE) * ITEM_SIZE;
	uint msg_rem = msg_dsz;

	list_for_each_entry(publ, pls, local_list) {
	/* Prepare next buffer: */
	if (!skb) {
	skb = named_prepare_buf(PUBLICATION, msg_rem, dnode);
	if (!skb) {
	pr_warn("Bulk publication failure\n");
	return;
	}
	item = (struct distr_item *)msg_data(buf_msg(skb));
	}

	/* Pack publication into message: */
	publ_to_item(item, publ);
	item++;
	msg_rem -= ITEM_SIZE;

	/* Append full buffer to list: */
	if (!msg_rem) {
	__skb_queue_tail(list, skb);
	skb = NULL;
	msg_rem = msg_dsz;
	}
	}
	if (skb) {
	msg_set_size(buf_msg(skb), INT_H_SIZE + (msg_dsz - msg_rem));
	skb_trim(skb, INT_H_SIZE + (msg_dsz - msg_rem));
	__skb_queue_tail(list, skb);
	}
	}

	/**
	* tipc_named_node_up - tell specified node about all publications by this node
	*/
	void tipc_named_node_up(u32 dnode)
	{
	struct sk_buff_head head;

	__skb_queue_head_init(&head);

	rcu_read_lock();
	named_distribute(&head, dnode,
	&tipc_nametbl->publ_list[TIPC_CLUSTER_SCOPE]);
	named_distribute(&head, dnode,
	&tipc_nametbl->publ_list[TIPC_ZONE_SCOPE]);
	rcu_read_unlock();

	tipc_link_xmit(&head, dnode, dnode);
	}

	static void tipc_publ_subscribe(struct publication *publ, u32 addr)
	{
	struct tipc_node *node;

	if (in_own_node(addr))
	return;

	node = tipc_node_find(addr);
	if (!node) {
	pr_warn("Node subscription rejected, unknown node 0x%x\n",
	addr);
	return;
	}

	tipc_node_lock(node);
	list_add_tail(&publ->nodesub_list, &node->publ_list);
	tipc_node_unlock(node);
	}

	static void tipc_publ_unsubscribe(struct publication *publ, u32 addr)
	{
	struct tipc_node *node;

	node = tipc_node_find(addr);
	if (!node)
	return;

	tipc_node_lock(node);
	list_del_init(&publ->nodesub_list);
	tipc_node_unlock(node);
	}

	/**
	* tipc_publ_purge - remove publication associated with a failed node
	*
	* Invoked for each publication issued by a newly failed node.
	* Removes publication structure from name table & deletes it.
	*/
	static void tipc_publ_purge(struct publication *publ, u32 addr)
	{
	struct publication *p;

	spin_lock_bh(&tipc_nametbl_lock);
	p = tipc_nametbl_remove_publ(publ->type, publ->lower,
	publ->node, publ->ref, publ->key);
	if (p)
	tipc_publ_unsubscribe(p, addr);
	spin_unlock_bh(&tipc_nametbl_lock);

	if (p != publ) {
	pr_err("Unable to remove publication from failed node\n"
	" (type=%u, lower=%u, node=0x%x, ref=%u, key=%u)\n",
	publ->type, publ->lower, publ->node, publ->ref,
	publ->key);
	}

	kfree_rcu(p, rcu);
	}

	void tipc_publ_notify(struct list_head *nsub_list, u32 addr)
	{
	struct publication publ, tmp;

	list_for_each_entry_safe(publ, tmp, nsub_list, nodesub_list)
	tipc_publ_purge(publ, addr);
	}

	/**
	* tipc_update_nametbl - try to process a nametable update and notify
	* subscribers
	*
	* tipc_nametbl_lock must be held.
	* Returns the publication item if successful, otherwise NULL.
	*/
	static bool tipc_update_nametbl(struct distr_item *i, u32 node, u32 dtype)
	{
	struct publication *publ = NULL;

	if (dtype == PUBLICATION) {
	publ = tipc_nametbl_insert_publ(ntohl(i->type), ntohl(i->lower),
	ntohl(i->upper),
	TIPC_CLUSTER_SCOPE, node,
	ntohl(i->ref), ntohl(i->key));
	if (publ) {
	tipc_publ_subscribe(publ, node);
	return true;
	}
	} else if (dtype == WITHDRAWAL) {
	publ = tipc_nametbl_remove_publ(ntohl(i->type), ntohl(i->lower),
	node, ntohl(i->ref),
	ntohl(i->key));
	if (publ) {
	tipc_publ_unsubscribe(publ, node);
	kfree_rcu(publ, rcu);
	return true;
	}
	} else {
	pr_warn("Unrecognized name table message received\n");
	}
	return false;
	}

	/**
	* tipc_named_add_backlog - add a failed name table update to the backlog
	*
	*/
	static void tipc_named_add_backlog(struct distr_item *i, u32 type, u32 node)
	{
	struct distr_queue_item *e;
	unsigned long now = get_jiffies_64();

	e = kzalloc(sizeof(*e), GFP_ATOMIC);
	if (!e)
	return;
	e->dtype = type;
	e->node = node;
	e->expires = now + msecs_to_jiffies(sysctl_tipc_named_timeout);
	memcpy(e, i, sizeof(*i));
	list_add_tail(&e->next, &tipc_dist_queue);
	}

	/**
	* tipc_named_process_backlog - try to process any pending name table updates
	* from the network.
	*/
	void tipc_named_process_backlog(void)
	{
	struct distr_queue_item e, tmp;
	char addr[16];
	unsigned long now = get_jiffies_64();

	list_for_each_entry_safe(e, tmp, &tipc_dist_queue, next) {
	if (time_after(e->expires, now)) {
	if (!tipc_update_nametbl(&e->i, e->node, e->dtype))
	continue;
	} else {
	tipc_addr_string_fill(addr, e->node);
	pr_warn_ratelimited("Dropping name table update (%d) of {%u, %u, %u} from %s key=%u\n",
	e->dtype, ntohl(e->i.type),
	ntohl(e->i.lower),
	ntohl(e->i.upper),
	addr, ntohl(e->i.key));
	}
	list_del(&e->next);
	kfree(e);
	}
	}

	/**
	* tipc_named_rcv - process name table update message sent by another node
	*/
	void tipc_named_rcv(struct sk_buff *buf)
	{
	struct tipc_msg *msg = buf_msg(buf);
	struct distr_item item = (struct distr_item )msg_data(msg);
	u32 count = msg_data_sz(msg) / ITEM_SIZE;
	u32 node = msg_orignode(msg);

	spin_lock_bh(&tipc_nametbl_lock);
	while (count--) {
	if (!tipc_update_nametbl(item, node, msg_type(msg)))
	tipc_named_add_backlog(item, msg_type(msg), node);
	item++;
	}
	tipc_named_process_backlog();
	spin_unlock_bh(&tipc_nametbl_lock);
	kfree_skb(buf);
	}

	/**
	* tipc_named_reinit - re-initialize local publications
	*
	* This routine is called whenever TIPC networking is enabled.
	* All name table entries published by this node are updated to reflect
	* the node's new network address.
	*/
	void tipc_named_reinit(void)
	{
	struct publication *publ;
	int scope;

	spin_lock_bh(&tipc_nametbl_lock);

	for (scope = TIPC_ZONE_SCOPE; scope <= TIPC_NODE_SCOPE; scope++)
	list_for_each_entry_rcu(publ, &tipc_nametbl->publ_list[scope],
	local_list)
	publ->node = tipc_own_addr;

	spin_unlock_bh(&tipc_nametbl_lock);
	}