text: /*
   * net/tipc/name_table.c: TIPC name table code
   *
   * Copyright (c) 2000-2006, 2014-2018, Ericsson AB
   * Copyright (c) 2004-2008, 2010-2014, 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 <net/sock.h>
  #include "core.h"
  #include "netlink.h"
  #include "name_table.h"
  #include "name_distr.h"
  #include "subscr.h"
  #include "bcast.h"
  #include "addr.h"
  #include "node.h"
  #include "group.h"
  
  /**
   * struct service_range - container for all bindings of a service range
   * @lower: service range lower bound
   * @upper: service range upper bound
   * @tree_node: member of service range RB tree
   * @local_publ: list of identical publications made from this node
   *   Used by closest_first lookup and multicast lookup algorithm
   * @all_publ: all publications identical to this one, whatever node and scope
   *   Used by round-robin lookup algorithm
   */
  struct service_range {
  	u32 lower;
  	u32 upper;
  	struct rb_node tree_node;
  	struct list_head local_publ;
  	struct list_head all_publ;
  };
  
  /**
   * struct tipc_service - container for all published instances of a service type
   * @type: 32 bit 'type' value for service
   * @ranges: rb tree containing all service ranges for this service
   * @service_list: links to adjacent name ranges in hash chain
   * @subscriptions: list of subscriptions for this service type
   * @lock: spinlock controlling access to pertaining service ranges/publications
   * @rcu: RCU callback head used for deferred freeing
   */
  struct tipc_service {
  	u32 type;
  	struct rb_root ranges;
  	struct hlist_node service_list;
  	struct list_head subscriptions;
  	spinlock_t lock; /* Covers service range list */
  	struct rcu_head rcu;
  };
  
  static int hash(int x)
  {
  	return x & (TIPC_NAMETBL_SIZE - 1);
  }
  
  /**
   * tipc_publ_create - create a publication structure
   */
  static struct publication *tipc_publ_create(u32 type, u32 lower, u32 upper,
  					    u32 scope, u32 node, u32 port,
  					    u32 key)
  {
  	struct publication *publ = kzalloc(sizeof(*publ), GFP_ATOMIC);
  
  	if (!publ)
  		return NULL;
  
  	publ->type = type;
  	publ->lower = lower;
  	publ->upper = upper;
  	publ->scope = scope;
  	publ->node = node;
  	publ->port = port;
  	publ->key = key;
  	INIT_LIST_HEAD(&publ->binding_sock);
  	INIT_LIST_HEAD(&publ->binding_node);
  	INIT_LIST_HEAD(&publ->local_publ);
  	INIT_LIST_HEAD(&publ->all_publ);
  	return publ;
  }
  
  /**
   * tipc_service_create - create a service structure for the specified 'type'
   *
   * Allocates a single range structure and sets it to all 0's.
   */
  static struct tipc_service *tipc_service_create(u32 type, struct hlist_head *hd)
  {
  	struct tipc_service *service = kzalloc(sizeof(*service), GFP_ATOMIC);
  
  	if (!service) {
  		pr_warn("Service creation failed, no memory\n");
  		return NULL;
  	}
  
  	spin_lock_init(&service->lock);
  	service->type = type;
  	service->ranges = RB_ROOT;
  	INIT_HLIST_NODE(&service->service_list);
  	INIT_LIST_HEAD(&service->subscriptions);
  	hlist_add_head_rcu(&service->service_list, hd);
  	return service;
  }
  
  /**
   * tipc_service_first_range - find first service range in tree matching instance
   *
   * Very time-critical, so binary search through range rb tree
   */
  static struct service_range *tipc_service_first_range(struct tipc_service *sc,
  						      u32 instance)
  {
  	struct rb_node *n = sc->ranges.rb_node;
  	struct service_range *sr;
  
  	while (n) {
  		sr = container_of(n, struct service_range, tree_node);
  		if (sr->lower > instance)
  			n = n->rb_left;
  		else if (sr->upper < instance)
  			n = n->rb_right;
  		else
  			return sr;
  	}
  	return NULL;
  }
  
  /*  tipc_service_find_range - find service range matching publication parameters
   */
  static struct service_range *tipc_service_find_range(struct tipc_service *sc,
  						     u32 lower, u32 upper)
  {
  	struct rb_node *n = sc->ranges.rb_node;
  	struct service_range *sr;
  
  	sr = tipc_service_first_range(sc, lower);
  	if (!sr)
  		return NULL;
  
  	/* Look for exact match */
  	for (n = &sr->tree_node; n; n = rb_next(n)) {
  		sr = container_of(n, struct service_range, tree_node);
  		if (sr->upper == upper)
  			break;
  	}
  	if (!n || sr->lower != lower || sr->upper != upper)
  		return NULL;
  
  	return sr;
  }
  
  static struct service_range *tipc_service_create_range(struct tipc_service *sc,
  						       u32 lower, u32 upper)
  {
  	struct rb_node **n, *parent = NULL;
  	struct service_range *sr, *tmp;
  
  	n = &sc->ranges.rb_node;
  	while (*n) {
  		tmp = container_of(*n, struct service_range, tree_node);
  		parent = *n;
  		tmp = container_of(parent, struct service_range, tree_node);
  		if (lower < tmp->lower)
  			n = &(*n)->rb_left;
  		else if (lower > tmp->lower)
  			n = &(*n)->rb_right;
  		else if (upper < tmp->upper)
  			n = &(*n)->rb_left;
  		else if (upper > tmp->upper)
  			n = &(*n)->rb_right;
  		else
  			return tmp;
  	}
  	sr = kzalloc(sizeof(*sr), GFP_ATOMIC);
  	if (!sr)
  		return NULL;
  	sr->lower = lower;
  	sr->upper = upper;
  	INIT_LIST_HEAD(&sr->local_publ);
  	INIT_LIST_HEAD(&sr->all_publ);
  	rb_link_node(&sr->tree_node, parent, n);
  	rb_insert_color(&sr->tree_node, &sc->ranges);
  	return sr;
  }
  
  static struct publication *tipc_service_insert_publ(struct net *net,
  						    struct tipc_service *sc,
  						    u32 type, u32 lower,
  						    u32 upper, u32 scope,
  						    u32 node, u32 port,
  						    u32 key)
  {
  	struct tipc_subscription *sub, *tmp;
  	struct service_range *sr;
  	struct publication *p;
  	bool first = false;
  
  	sr = tipc_service_create_range(sc, lower, upper);
  	if (!sr)
  		goto  err;
  
  	first = list_empty(&sr->all_publ);
  
  	/* Return if the publication already exists */
  	list_for_each_entry(p, &sr->all_publ, all_publ) {
  		if (p->key == key && (!p->node || p->node == node))
  			return NULL;
  	}
  
  	/* Create and insert publication */
  	p = tipc_publ_create(type, lower, upper, scope, node, port, key);
  	if (!p)
  		goto err;
  	if (in_own_node(net, node))
  		list_add(&p->local_publ, &sr->local_publ);
  	list_add(&p->all_publ, &sr->all_publ);
  
  	/* Any subscriptions waiting for notification?  */
  	list_for_each_entry_safe(sub, tmp, &sc->subscriptions, service_list) {
  		tipc_sub_report_overlap(sub, p->lower, p->upper, TIPC_PUBLISHED,
  					p->port, p->node, p->scope, first);
  	}
  	return p;
  err:
  	pr_warn("Failed to bind to %u,%u,%u, no memory\n", type, lower, upper);
  	return NULL;
  }
  
  /**
   * tipc_service_remove_publ - remove a publication from a service
   */
  static struct publication *tipc_service_remove_publ(struct service_range *sr,
  						    u32 node, u32 key)
  {
  	struct publication *p;
  
  	list_for_each_entry(p, &sr->all_publ, all_publ) {
  		if (p->key != key || (node && node != p->node))
  			continue;
  		list_del(&p->all_publ);
  		list_del(&p->local_publ);
  		return p;
  	}
  	return NULL;
  }
  
  /**
   * tipc_service_subscribe - attach a subscription, and optionally
   * issue the prescribed number of events if there is any service
   * range overlapping with the requested range
   */
  static void tipc_service_subscribe(struct tipc_service *service,
  				   struct tipc_subscription *sub)
  {
  	struct tipc_subscr *sb = &sub->evt.s;
  	struct service_range *sr;
  	struct tipc_name_seq ns;
  	struct publication *p;
  	struct rb_node *n;
  	bool first;
  
  	ns.type = tipc_sub_read(sb, seq.type);
  	ns.lower = tipc_sub_read(sb, seq.lower);
  	ns.upper = tipc_sub_read(sb, seq.upper);
  
  	tipc_sub_get(sub);
  	list_add(&sub->service_list, &service->subscriptions);
  
  	if (tipc_sub_read(sb, filter) & TIPC_SUB_NO_STATUS)
  		return;
  
  	for (n = rb_first(&service->ranges); n; n = rb_next(n)) {
  		sr = container_of(n, struct service_range, tree_node);
  		if (sr->lower > ns.upper)
  			break;
  		if (!tipc_sub_check_overlap(&ns, sr->lower, sr->upper))
  			continue;
  		first = true;
  
  		list_for_each_entry(p, &sr->all_publ, all_publ) {
  			tipc_sub_report_overlap(sub, sr->lower, sr->upper,
  						TIPC_PUBLISHED,	p->port,
  						p->node, p->scope, first);
  			first = false;
  		}
  	}
  }
  
  static struct tipc_service *tipc_service_find(struct net *net, u32 type)
  {
  	struct name_table *nt = tipc_name_table(net);
  	struct hlist_head *service_head;
  	struct tipc_service *service;
  
  	service_head = &nt->services[hash(type)];
  	hlist_for_each_entry_rcu(service, service_head, service_list) {
  		if (service->type == type)
  			return service;
  	}
  	return NULL;
  };
  
  struct publication *tipc_nametbl_insert_publ(struct net *net, u32 type,
  					     u32 lower, u32 upper,
  					     u32 scope, u32 node,
  					     u32 port, u32 key)
  {
  	struct name_table *nt = tipc_name_table(net);
  	struct tipc_service *sc;
  	struct publication *p;
  
  	if (scope > TIPC_NODE_SCOPE || lower > upper) {
  		pr_debug("Failed to bind illegal {%u,%u,%u} with scope %u\n",
  			 type, lower, upper, scope);
  		return NULL;
  	}
  	sc = tipc_service_find(net, type);
  	if (!sc)
  		sc = tipc_service_create(type, &nt->services[hash(type)]);
  	if (!sc)
  		return NULL;
  
  	spin_lock_bh(&sc->lock);
  	p = tipc_service_insert_publ(net, sc, type, lower, upper,
  				     scope, node, port, key);
  	spin_unlock_bh(&sc->lock);
  	return p;
  }
  
  struct publication *tipc_nametbl_remove_publ(struct net *net, u32 type,
  					     u32 lower, u32 upper,
  					     u32 node, u32 key)
  {
  	struct tipc_service *sc = tipc_service_find(net, type);
  	struct tipc_subscription *sub, *tmp;
  	struct service_range *sr = NULL;
  	struct publication *p = NULL;
  	bool last;
  
  	if (!sc)
  		return NULL;
  
  	spin_lock_bh(&sc->lock);
  	sr = tipc_service_find_range(sc, lower, upper);
  	if (!sr)
  		goto exit;
  	p = tipc_service_remove_publ(sr, node, key);
  	if (!p)
  		goto exit;
  
  	/* Notify any waiting subscriptions */
  	last = list_empty(&sr->all_publ);
  	list_for_each_entry_safe(sub, tmp, &sc->subscriptions, service_list) {
  		tipc_sub_report_overlap(sub, lower, upper, TIPC_WITHDRAWN,
  					p->port, node, p->scope, last);
  	}
  
  	/* Remove service range item if this was its last publication */
  	if (list_empty(&sr->all_publ)) {
  		rb_erase(&sr->tree_node, &sc->ranges);
  		kfree(sr);
  	}
  
  	/* Delete service item if this no more publications and subscriptions */
  	if (RB_EMPTY_ROOT(&sc->ranges) && list_empty(&sc->subscriptions)) {
  		hlist_del_init_rcu(&sc->service_list);
  		kfree_rcu(sc, rcu);
  	}
  exit:
  	spin_unlock_bh(&sc->lock);
  	return p;
  }
  
  /**
   * tipc_nametbl_translate - perform service instance to socket translation
   *
   * On entry, 'dnode' is the search domain used during translation.
   *
   * On exit:
   * - if translation is deferred to another node, leave 'dnode' unchanged and
   *   return 0
   * - if translation is attempted and succeeds, set 'dnode' to the publishing
   *   node and return the published (non-zero) port number
   * - if translation is attempted and fails, set 'dnode' to 0 and return 0
   *
   * Note that for legacy users (node configured with Z.C.N address format) the
   * 'closest-first' lookup algorithm must be maintained, i.e., if dnode is 0
   * we must look in the local binding list first
   */
  u32 tipc_nametbl_translate(struct net *net, u32 type, u32 instance, u32 *dnode)
  {
  	struct tipc_net *tn = tipc_net(net);
  	bool legacy = tn->legacy_addr_format;
  	u32 self = tipc_own_addr(net);
  	struct service_range *sr;
  	struct tipc_service *sc;
  	struct list_head *list;
  	struct publication *p;
  	u32 port = 0;
  	u32 node = 0;
  
  	if (!tipc_in_scope(legacy, *dnode, self))
  		return 0;
  
  	rcu_read_lock();
  	sc = tipc_service_find(net, type);
  	if (unlikely(!sc))
  		goto not_found;
  
  	spin_lock_bh(&sc->lock);
  	sr = tipc_service_first_range(sc, instance);
  	if (unlikely(!sr))
  		goto no_match;
  
  	/* Select lookup algorithm: local, closest-first or round-robin */
  	if (*dnode == self) {
  		list = &sr->local_publ;
  		if (list_empty(list))
  			goto no_match;
  		p = list_first_entry(list, struct publication, local_publ);
  		list_move_tail(&p->local_publ, &sr->local_publ);
  	} else if (legacy && !*dnode && !list_empty(&sr->local_publ)) {
  		list = &sr->local_publ;
  		p = list_first_entry(list, struct publication, local_publ);
  		list_move_tail(&p->local_publ, &sr->local_publ);
  	} else {
  		list = &sr->all_publ;
  		p = list_first_entry(list, struct publication, all_publ);
  		list_move_tail(&p->all_publ, &sr->all_publ);
  	}
  	port = p->port;
  	node = p->node;
  no_match:
  	spin_unlock_bh(&sc->lock);
  not_found:
  	rcu_read_unlock();
  	*dnode = node;
  	return port;
  }
  
  bool tipc_nametbl_lookup(struct net *net, u32 type, u32 instance, u32 scope,
  			 struct list_head *dsts, int *dstcnt, u32 exclude,
  			 bool all)
  {
  	u32 self = tipc_own_addr(net);
  	struct service_range *sr;
  	struct tipc_service *sc;
  	struct publication *p;
  
  	*dstcnt = 0;
  	rcu_read_lock();
  	sc = tipc_service_find(net, type);
  	if (unlikely(!sc))
  		goto exit;
  
  	spin_lock_bh(&sc->lock);
  
  	sr = tipc_service_first_range(sc, instance);
  	if (!sr)
  		goto no_match;
  
  	list_for_each_entry(p, &sr->all_publ, all_publ) {
  		if (p->scope != scope)
  			continue;
  		if (p->port == exclude && p->node == self)
  			continue;
  		tipc_dest_push(dsts, p->node, p->port);
  		(*dstcnt)++;
  		if (all)
  			continue;
  		list_move_tail(&p->all_publ, &sr->all_publ);
  		break;
  	}
  no_match:
  	spin_unlock_bh(&sc->lock);
  exit:
  	rcu_read_unlock();
  	return !list_empty(dsts);
  }
  
  void tipc_nametbl_mc_lookup(struct net *net, u32 type, u32 lower, u32 upper,
  			    u32 scope, bool exact, struct list_head *dports)
  {
  	struct service_range *sr;
  	struct tipc_service *sc;
  	struct publication *p;
  	struct rb_node *n;
  
  	rcu_read_lock();
  	sc = tipc_service_find(net, type);
  	if (!sc)
  		goto exit;
  
  	spin_lock_bh(&sc->lock);
  
  	for (n = rb_first(&sc->ranges); n; n = rb_next(n)) {
  		sr = container_of(n, struct service_range, tree_node);
  		if (sr->upper < lower)
  			continue;
  		if (sr->lower > upper)
  			break;
  		list_for_each_entry(p, &sr->local_publ, local_publ) {
  			if (p->scope == scope || (!exact && p->scope < scope))
  				tipc_dest_push(dports, 0, p->port);
  		}
  	}
  	spin_unlock_bh(&sc->lock);
  exit:
  	rcu_read_unlock();
  }
  
  /* tipc_nametbl_lookup_dst_nodes - find broadcast destination nodes
   * - Creates list of nodes that overlap the given multicast address
   * - Determines if any node local destinations overlap
   */
  void tipc_nametbl_lookup_dst_nodes(struct net *net, u32 type, u32 lower,
  				   u32 upper, struct tipc_nlist *nodes)
  {
  	struct service_range *sr;
  	struct tipc_service *sc;
  	struct publication *p;
  	struct rb_node *n;
  
  	rcu_read_lock();
  	sc = tipc_service_find(net, type);
  	if (!sc)
  		goto exit;
  
  	spin_lock_bh(&sc->lock);
  
  	for (n = rb_first(&sc->ranges); n; n = rb_next(n)) {
  		sr = container_of(n, struct service_range, tree_node);
  		if (sr->upper < lower)
  			continue;
  		if (sr->lower > upper)
  			break;
  		list_for_each_entry(p, &sr->all_publ, all_publ) {
  			tipc_nlist_add(nodes, p->node);
  		}
  	}
  	spin_unlock_bh(&sc->lock);
  exit:
  	rcu_read_unlock();
  }
  
  /* tipc_nametbl_build_group - build list of communication group members
   */
  void tipc_nametbl_build_group(struct net *net, struct tipc_group *grp,
  			      u32 type, u32 scope)
  {
  	struct service_range *sr;
  	struct tipc_service *sc;
  	struct publication *p;
  	struct rb_node *n;
  
  	rcu_read_lock();
  	sc = tipc_service_find(net, type);
  	if (!sc)
  		goto exit;
  
  	spin_lock_bh(&sc->lock);
  	for (n = rb_first(&sc->ranges); n; n = rb_next(n)) {
  		sr = container_of(n, struct service_range, tree_node);
  		list_for_each_entry(p, &sr->all_publ, all_publ) {
  			if (p->scope != scope)
  				continue;
  			tipc_group_add_member(grp, p->node, p->port, p->lower);
  		}
  	}
  	spin_unlock_bh(&sc->lock);
  exit:
  	rcu_read_unlock();
  }
  
  /* tipc_nametbl_publish - add service binding to name table
   */
  struct publication *tipc_nametbl_publish(struct net *net, u32 type, u32 lower,
  					 u32 upper, u32 scope, u32 port,
  					 u32 key)
  {
  	struct name_table *nt = tipc_name_table(net);
  	struct tipc_net *tn = tipc_net(net);
  	struct publication *p = NULL;
  	struct sk_buff *skb = NULL;
  
  	spin_lock_bh(&tn->nametbl_lock);
  
  	if (nt->local_publ_count >= TIPC_MAX_PUBL) {
  		pr_warn("Bind failed, max limit %u reached\n", TIPC_MAX_PUBL);
  		goto exit;
  	}
  
  	p = tipc_nametbl_insert_publ(net, type, lower, upper, scope,
  				     tipc_own_addr(net), port, key);
  	if (p) {
  		nt->local_publ_count++;
  		skb = tipc_named_publish(net, p);
  	}
  exit:
  	spin_unlock_bh(&tn->nametbl_lock);
  
  	if (skb)
  		tipc_node_broadcast(net, skb);
  	return p;
  }
  
  /**
   * tipc_nametbl_withdraw - withdraw a service binding
   */
  int tipc_nametbl_withdraw(struct net *net, u32 type, u32 lower,
  			  u32 upper, u32 key)
  {
  	struct name_table *nt = tipc_name_table(net);
  	struct tipc_net *tn = tipc_net(net);
  	u32 self = tipc_own_addr(net);
  	struct sk_buff *skb = NULL;
  	struct publication *p;
  
  	spin_lock_bh(&tn->nametbl_lock);
  
  	p = tipc_nametbl_remove_publ(net, type, lower, upper, self, key);
  	if (p) {
  		nt->local_publ_count--;
  		skb = tipc_named_withdraw(net, p);
  		list_del_init(&p->binding_sock);
  		kfree_rcu(p, rcu);
  	} else {
  		pr_err("Failed to remove local publication {%u,%u,%u}/%u\n",
  		       type, lower, upper, key);
  	}
  	spin_unlock_bh(&tn->nametbl_lock);
  
  	if (skb) {
  		tipc_node_broadcast(net, skb);
  		return 1;
  	}
  	return 0;
  }
  
  /**
   * tipc_nametbl_subscribe - add a subscription object to the name table
   */
  bool tipc_nametbl_subscribe(struct tipc_subscription *sub)
  {
  	struct name_table *nt = tipc_name_table(sub->net);
  	struct tipc_net *tn = tipc_net(sub->net);
  	struct tipc_subscr *s = &sub->evt.s;
  	u32 type = tipc_sub_read(s, seq.type);
  	struct tipc_service *sc;
  	bool res = true;
  
  	spin_lock_bh(&tn->nametbl_lock);
  	sc = tipc_service_find(sub->net, type);
  	if (!sc)
  		sc = tipc_service_create(type, &nt->services[hash(type)]);
  	if (sc) {
  		spin_lock_bh(&sc->lock);
  		tipc_service_subscribe(sc, sub);
  		spin_unlock_bh(&sc->lock);
  	} else {
  		pr_warn("Failed to subscribe for {%u,%u,%u}\n", type,
  			tipc_sub_read(s, seq.lower),
  			tipc_sub_read(s, seq.upper));
  		res = false;
  	}
  	spin_unlock_bh(&tn->nametbl_lock);
  	return res;
  }
  
  /**
   * tipc_nametbl_unsubscribe - remove a subscription object from name table
   */
  void tipc_nametbl_unsubscribe(struct tipc_subscription *sub)
  {
  	struct tipc_net *tn = tipc_net(sub->net);
  	struct tipc_subscr *s = &sub->evt.s;
  	u32 type = tipc_sub_read(s, seq.type);
  	struct tipc_service *sc;
  
  	spin_lock_bh(&tn->nametbl_lock);
  	sc = tipc_service_find(sub->net, type);
  	if (!sc)
  		goto exit;
  
  	spin_lock_bh(&sc->lock);
  	list_del_init(&sub->service_list);
  	tipc_sub_put(sub);
  
  	/* Delete service item if no more publications and subscriptions */
  	if (RB_EMPTY_ROOT(&sc->ranges) && list_empty(&sc->subscriptions)) {
  		hlist_del_init_rcu(&sc->service_list);
  		kfree_rcu(sc, rcu);
  	}
  	spin_unlock_bh(&sc->lock);
  exit:
  	spin_unlock_bh(&tn->nametbl_lock);
  }
  
  int tipc_nametbl_init(struct net *net)
  {
  	struct tipc_net *tn = tipc_net(net);
  	struct name_table *nt;
  	int i;
  
  	nt = kzalloc(sizeof(*nt), GFP_KERNEL);
  	if (!nt)
  		return -ENOMEM;
  
  	for (i = 0; i < TIPC_NAMETBL_SIZE; i++)
  		INIT_HLIST_HEAD(&nt->services[i]);
  
  	INIT_LIST_HEAD(&nt->node_scope);
  	INIT_LIST_HEAD(&nt->cluster_scope);
  	rwlock_init(&nt->cluster_scope_lock);
  	tn->nametbl = nt;
  	spin_lock_init(&tn->nametbl_lock);
  	return 0;
  }
  
  /**
   *  tipc_service_delete - purge all publications for a service and delete it
   */
  static void tipc_service_delete(struct net *net, struct tipc_service *sc)
  {
  	struct service_range *sr, *tmpr;
  	struct publication *p, *tmp;
  
  	spin_lock_bh(&sc->lock);
  	rbtree_postorder_for_each_entry_safe(sr, tmpr, &sc->ranges, tree_node) {
  		list_for_each_entry_safe(p, tmp, &sr->all_publ, all_publ) {
  			tipc_service_remove_publ(sr, p->node, p->key);
  			kfree_rcu(p, rcu);
  		}
  		rb_erase(&sr->tree_node, &sc->ranges);
  		kfree(sr);
  	}
  	hlist_del_init_rcu(&sc->service_list);
  	spin_unlock_bh(&sc->lock);
  	kfree_rcu(sc, rcu);
  }
  
  void tipc_nametbl_stop(struct net *net)
  {
  	struct name_table *nt = tipc_name_table(net);
  	struct tipc_net *tn = tipc_net(net);
  	struct hlist_head *service_head;
  	struct tipc_service *service;
  	u32 i;
  
  	/* Verify name table is empty and purge any lingering
  	 * publications, then release the name table
  	 */
  	spin_lock_bh(&tn->nametbl_lock);
  	for (i = 0; i < TIPC_NAMETBL_SIZE; i++) {
  		if (hlist_empty(&nt->services[i]))
  			continue;
  		service_head = &nt->services[i];
  		hlist_for_each_entry_rcu(service, service_head, service_list) {
  			tipc_service_delete(net, service);
  		}
  	}
  	spin_unlock_bh(&tn->nametbl_lock);
  
  	synchronize_net();
  	kfree(nt);
  }
  
  static int __tipc_nl_add_nametable_publ(struct tipc_nl_msg *msg,
  					struct tipc_service *service,
  					struct service_range *sr,
  					u32 *last_key)
  {
  	struct publication *p;
  	struct nlattr *attrs;
  	struct nlattr *b;
  	void *hdr;
  
  	if (*last_key) {
  		list_for_each_entry(p, &sr->all_publ, all_publ)
  			if (p->key == *last_key)
  				break;
  		if (p->key != *last_key)
  			return -EPIPE;
  	} else {
  		p = list_first_entry(&sr->all_publ,
  				     struct publication,
  				     all_publ);
  	}
  
  	list_for_each_entry_from(p, &sr->all_publ, all_publ) {
  		*last_key = p->key;
  
  		hdr = genlmsg_put(msg->skb, msg->portid, msg->seq,
  				  &tipc_genl_family, NLM_F_MULTI,
  				  TIPC_NL_NAME_TABLE_GET);
  		if (!hdr)
  			return -EMSGSIZE;
  
  		attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_NAME_TABLE);
  		if (!attrs)
  			goto msg_full;
  
  		b = nla_nest_start_noflag(msg->skb, TIPC_NLA_NAME_TABLE_PUBL);
  		if (!b)
  			goto attr_msg_full;
  
  		if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_TYPE, service->type))
  			goto publ_msg_full;
  		if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_LOWER, sr->lower))
  			goto publ_msg_full;
  		if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_UPPER, sr->upper))
  			goto publ_msg_full;
  		if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_SCOPE, p->scope))
  			goto publ_msg_full;
  		if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_NODE, p->node))
  			goto publ_msg_full;
  		if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_REF, p->port))
  			goto publ_msg_full;
  		if (nla_put_u32(msg->skb, TIPC_NLA_PUBL_KEY, p->key))
  			goto publ_msg_full;
  
  		nla_nest_end(msg->skb, b);
  		nla_nest_end(msg->skb, attrs);
  		genlmsg_end(msg->skb, hdr);
  	}
  	*last_key = 0;
  
  	return 0;
  
  publ_msg_full:
  	nla_nest_cancel(msg->skb, b);
  attr_msg_full:
  	nla_nest_cancel(msg->skb, attrs);
  msg_full:
  	genlmsg_cancel(msg->skb, hdr);
  
  	return -EMSGSIZE;
  }
  
  static int __tipc_nl_service_range_list(struct tipc_nl_msg *msg,
  					struct tipc_service *sc,
  					u32 *last_lower, u32 *last_key)
  {
  	struct service_range *sr;
  	struct rb_node *n;
  	int err;
  
  	for (n = rb_first(&sc->ranges); n; n = rb_next(n)) {
  		sr = container_of(n, struct service_range, tree_node);
  		if (sr->lower < *last_lower)
  			continue;
  		err = __tipc_nl_add_nametable_publ(msg, sc, sr, last_key);
  		if (err) {
  			*last_lower = sr->lower;
  			return err;
  		}
  	}
  	*last_lower = 0;
  	return 0;
  }
  
  static int tipc_nl_service_list(struct net *net, struct tipc_nl_msg *msg,
  				u32 *last_type, u32 *last_lower, u32 *last_key)
  {
  	struct tipc_net *tn = tipc_net(net);
  	struct tipc_service *service = NULL;
  	struct hlist_head *head;
  	int err;
  	int i;
  
  	if (*last_type)
  		i = hash(*last_type);
  	else
  		i = 0;
  
  	for (; i < TIPC_NAMETBL_SIZE; i++) {
  		head = &tn->nametbl->services[i];
  
  		if (*last_type ||
  		    (!i && *last_key && (*last_lower == *last_key))) {
  			service = tipc_service_find(net, *last_type);
  			if (!service)
  				return -EPIPE;
  		} else {
  			hlist_for_each_entry_rcu(service, head, service_list)
  				break;
  			if (!service)
  				continue;
  		}
  
  		hlist_for_each_entry_from_rcu(service, service_list) {
  			spin_lock_bh(&service->lock);
  			err = __tipc_nl_service_range_list(msg, service,
  							   last_lower,
  							   last_key);
  
  			if (err) {
  				*last_type = service->type;
  				spin_unlock_bh(&service->lock);
  				return err;
  			}
  			spin_unlock_bh(&service->lock);
  		}
  		*last_type = 0;
  	}
  	return 0;
  }
  
  int tipc_nl_name_table_dump(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	struct net *net = sock_net(skb->sk);
  	u32 last_type = cb->args[0];
  	u32 last_lower = cb->args[1];
  	u32 last_key = cb->args[2];
  	int done = cb->args[3];
  	struct tipc_nl_msg msg;
  	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();
  	err = tipc_nl_service_list(net, &msg, &last_type,
  				   &last_lower, &last_key);
  	if (!err) {
  		done = 1;
  	} else if (err != -EMSGSIZE) {
  		/* 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 NLMSG_DONE message having the NLM_F_DUMP_INTR flag set if
  		 * we got an error.
  		 */
  		cb->prev_seq = 1;
  	}
  	rcu_read_unlock();
  
  	cb->args[0] = last_type;
  	cb->args[1] = last_lower;
  	cb->args[2] = last_key;
  	cb->args[3] = done;
  
  	return skb->len;
  }
  
  struct tipc_dest *tipc_dest_find(struct list_head *l, u32 node, u32 port)
  {
  	struct tipc_dest *dst;
  
  	list_for_each_entry(dst, l, list) {
  		if (dst->node == node && dst->port == port)
  			return dst;
  	}
  	return NULL;
  }
  
  bool tipc_dest_push(struct list_head *l, u32 node, u32 port)
  {
  	struct tipc_dest *dst;
  
  	if (tipc_dest_find(l, node, port))
  		return false;
  
  	dst = kmalloc(sizeof(*dst), GFP_ATOMIC);
  	if (unlikely(!dst))
  		return false;
  	dst->node = node;
  	dst->port = port;
  	list_add(&dst->list, l);
  	return true;
  }
  
  bool tipc_dest_pop(struct list_head *l, u32 *node, u32 *port)
  {
  	struct tipc_dest *dst;
  
  	if (list_empty(l))
  		return false;
  	dst = list_first_entry(l, typeof(*dst), list);
  	if (port)
  		*port = dst->port;
  	if (node)
  		*node = dst->node;
  	list_del(&dst->list);
  	kfree(dst);
  	return true;
  }
  
  bool tipc_dest_del(struct list_head *l, u32 node, u32 port)
  {
  	struct tipc_dest *dst;
  
  	dst = tipc_dest_find(l, node, port);
  	if (!dst)
  		return false;
  	list_del(&dst->list);
  	kfree(dst);
  	return true;
  }
  
  void tipc_dest_list_purge(struct list_head *l)
  {
  	struct tipc_dest *dst, *tmp;
  
  	list_for_each_entry_safe(dst, tmp, l, list) {
  		list_del(&dst->list);
  		kfree(dst);
  	}
  }
  
  int tipc_dest_list_len(struct list_head *l)
  {
  	struct tipc_dest *dst;
  	int i = 0;
  
  	list_for_each_entry(dst, l, list) {
  		i++;
  	}
  	return i;
  }
  