text: /*
   * 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 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->port = htonl(p->port);
  	i->key = htonl(p->key);
  }
  
  /**
   * named_prepare_buf - allocate & initialize a publication message
   *
   * The buffer returned is of size INT_H_SIZE + payload size
   */
  static struct sk_buff *named_prepare_buf(struct net *net, u32 type, u32 size,
  					 u32 dest)
  {
  	struct sk_buff *buf = tipc_buf_acquire(INT_H_SIZE + size, GFP_ATOMIC);
  	u32 self = tipc_own_addr(net);
  	struct tipc_msg *msg;
  
  	if (buf != NULL) {
  		msg = buf_msg(buf);
  		tipc_msg_init(self, msg, NAME_DISTRIBUTOR,
  			      type, INT_H_SIZE, dest);
  		msg_set_size(msg, INT_H_SIZE + size);
  	}
  	return buf;
  }
  
  /**
   * tipc_named_publish - tell other nodes about a new publication by this node
   */
  struct sk_buff *tipc_named_publish(struct net *net, struct publication *publ)
  {
  	struct name_table *nt = tipc_name_table(net);
  	struct distr_item *item;
  	struct sk_buff *skb;
  
  	if (publ->scope == TIPC_NODE_SCOPE) {
  		list_add_tail_rcu(&publ->binding_node, &nt->node_scope);
  		return NULL;
  	}
  	write_lock_bh(&nt->cluster_scope_lock);
  	list_add_tail(&publ->binding_node, &nt->cluster_scope);
  	write_unlock_bh(&nt->cluster_scope_lock);
  	skb = named_prepare_buf(net, PUBLICATION, ITEM_SIZE, 0);
  	if (!skb) {
  		pr_warn("Publication distribution failure\n");
  		return NULL;
  	}
  
  	item = (struct distr_item *)msg_data(buf_msg(skb));
  	publ_to_item(item, publ);
  	return skb;
  }
  
  /**
   * tipc_named_withdraw - tell other nodes about a withdrawn publication by this node
   */
  struct sk_buff *tipc_named_withdraw(struct net *net, struct publication *publ)
  {
  	struct name_table *nt = tipc_name_table(net);
  	struct sk_buff *buf;
  	struct distr_item *item;
  
  	write_lock_bh(&nt->cluster_scope_lock);
  	list_del(&publ->binding_node);
  	write_unlock_bh(&nt->cluster_scope_lock);
  	if (publ->scope == TIPC_NODE_SCOPE)
  		return NULL;
  
  	buf = named_prepare_buf(net, 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 net *net, struct sk_buff_head *list,
  			     u32 dnode, struct list_head *pls)
  {
  	struct publication *publ;
  	struct sk_buff *skb = NULL;
  	struct distr_item *item = NULL;
  	u32 msg_dsz = ((tipc_node_get_mtu(net, dnode, 0) - INT_H_SIZE) /
  			ITEM_SIZE) * ITEM_SIZE;
  	u32 msg_rem = msg_dsz;
  
  	list_for_each_entry(publ, pls, binding_node) {
  		/* Prepare next buffer: */
  		if (!skb) {
  			skb = named_prepare_buf(net, PUBLICATION, msg_rem,
  						dnode);
  			if (!skb) {
  				pr_warn("Bulk publication failure\n");
  				return;
  			}
  			msg_set_bc_ack_invalid(buf_msg(skb), true);
  			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(struct net *net, u32 dnode)
  {
  	struct name_table *nt = tipc_name_table(net);
  	struct sk_buff_head head;
  
  	skb_queue_head_init(&head);
  
  	read_lock_bh(&nt->cluster_scope_lock);
  	named_distribute(net, &head, dnode, &nt->cluster_scope);
  	tipc_node_xmit(net, &head, dnode, 0);
  	read_unlock_bh(&nt->cluster_scope_lock);
  }
  
  /**
   * 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 net *net, struct publication *publ, u32 addr)
  {
  	struct tipc_net *tn = tipc_net(net);
  	struct publication *p;
  
  	spin_lock_bh(&tn->nametbl_lock);
  	p = tipc_nametbl_remove_publ(net, publ->type, publ->lower, publ->upper,
  				     publ->node, publ->key);
  	if (p)
  		tipc_node_unsubscribe(net, &p->binding_node, addr);
  	spin_unlock_bh(&tn->nametbl_lock);
  
  	if (p != publ) {
  		pr_err("Unable to remove publication from failed node\n"
  		       " (type=%u, lower=%u, node=0x%x, port=%u, key=%u)\n",
  		       publ->type, publ->lower, publ->node, publ->port,
  		       publ->key);
  	}
  
  	kfree_rcu(p, rcu);
  }
  
  /**
   * tipc_dist_queue_purge - remove deferred updates from a node that went down
   */
  static void tipc_dist_queue_purge(struct net *net, u32 addr)
  {
  	struct tipc_net *tn = net_generic(net, tipc_net_id);
  	struct distr_queue_item *e, *tmp;
  
  	spin_lock_bh(&tn->nametbl_lock);
  	list_for_each_entry_safe(e, tmp, &tn->dist_queue, next) {
  		if (e->node != addr)
  			continue;
  		list_del(&e->next);
  		kfree(e);
  	}
  	spin_unlock_bh(&tn->nametbl_lock);
  }
  
  void tipc_publ_notify(struct net *net, struct list_head *nsub_list, u32 addr)
  {
  	struct publication *publ, *tmp;
  
  	list_for_each_entry_safe(publ, tmp, nsub_list, binding_node)
  		tipc_publ_purge(net, publ, addr);
  	tipc_dist_queue_purge(net, 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 net *net, struct distr_item *i,
  				u32 node, u32 dtype)
  {
  	struct publication *p = NULL;
  	u32 lower = ntohl(i->lower);
  	u32 upper = ntohl(i->upper);
  	u32 type = ntohl(i->type);
  	u32 port = ntohl(i->port);
  	u32 key = ntohl(i->key);
  
  	if (dtype == PUBLICATION) {
  		p = tipc_nametbl_insert_publ(net, type, lower, upper,
  					     TIPC_CLUSTER_SCOPE, node,
  					     port, key);
  		if (p) {
  			tipc_node_subscribe(net, &p->binding_node, node);
  			return true;
  		}
  	} else if (dtype == WITHDRAWAL) {
  		p = tipc_nametbl_remove_publ(net, type, lower,
  					     upper, node, key);
  		if (p) {
  			tipc_node_unsubscribe(net, &p->binding_node, node);
  			kfree_rcu(p, rcu);
  			return true;
  		}
  		pr_warn_ratelimited("Failed to remove binding %u,%u from %x\n",
  				    type, lower, node);
  	} else {
  		pr_warn("Unrecognized name table message received\n");
  	}
  	return false;
  }
  
  /**
   * tipc_named_rcv - process name table update messages sent by another node
   */
  void tipc_named_rcv(struct net *net, struct sk_buff_head *inputq)
  {
  	struct tipc_net *tn = net_generic(net, tipc_net_id);
  	struct tipc_msg *msg;
  	struct distr_item *item;
  	uint count;
  	u32 node;
  	struct sk_buff *skb;
  	int mtype;
  
  	spin_lock_bh(&tn->nametbl_lock);
  	for (skb = skb_dequeue(inputq); skb; skb = skb_dequeue(inputq)) {
  		skb_linearize(skb);
  		msg = buf_msg(skb);
  		mtype = msg_type(msg);
  		item = (struct distr_item *)msg_data(msg);
  		count = msg_data_sz(msg) / ITEM_SIZE;
  		node = msg_orignode(msg);
  		while (count--) {
  			tipc_update_nametbl(net, item, node, mtype);
  			item++;
  		}
  		kfree_skb(skb);
  	}
  	spin_unlock_bh(&tn->nametbl_lock);
  }
  
  /**
   * 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(struct net *net)
  {
  	struct name_table *nt = tipc_name_table(net);
  	struct tipc_net *tn = tipc_net(net);
  	struct publication *publ;
  	u32 self = tipc_own_addr(net);
  
  	spin_lock_bh(&tn->nametbl_lock);
  
  	list_for_each_entry_rcu(publ, &nt->node_scope, binding_node)
  		publ->node = self;
  	list_for_each_entry_rcu(publ, &nt->cluster_scope, binding_node)
  		publ->node = self;
  
  	spin_unlock_bh(&tn->nametbl_lock);
  }
  