/*
   * net/tipc/name_distr.c: TIPC name distribution code
   *
   * Copyright (c) 2000-2006, 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"
  
  #define ITEM_SIZE sizeof(struct distr_item)
  
  /**
   * struct distr_item - publication info distributed to other nodes
   * @type: name sequence type
   * @lower: name sequence lower bound
   * @upper: name sequence upper bound
   * @ref: publishing port reference
   * @key: publication key
   *
   * ===> All fields are stored in network byte order. <===
   *
   * First 3 fields identify (name or) name sequence being published.
   * Reference field uniquely identifies port that published name sequence.
   * Key field uniquely identifies publication, in the event a port has
   * multiple publications of the same name sequence.
   *
   * Note: There is no field that identifies the publishing node because it is
   * the same for all items contained within a publication message.
   */
  struct distr_item {
  	__be32 type;
  	__be32 lower;
  	__be32 upper;
  	__be32 ref;
  	__be32 key;
  };
  
  /**
   * struct publ_list - list of publications made by this node
   * @list: circular list of publications
   * @list_size: number of entries in list
   */
  struct publ_list {
  	struct list_head list;
  	u32 size;
  };
  
  static struct publ_list publ_zone = {
  	.list = LIST_HEAD_INIT(publ_zone.list),
  	.size = 0,
  };
  
  static struct publ_list publ_cluster = {
  	.list = LIST_HEAD_INIT(publ_cluster.list),
  	.size = 0,
  };
  
  static struct publ_list publ_node = {
  	.list = LIST_HEAD_INIT(publ_node.list),
  	.size = 0,
  };
  
  static struct publ_list *publ_lists[] = {
  	NULL,
  	&publ_zone,	/* publ_lists[TIPC_ZONE_SCOPE]		*/
  	&publ_cluster,	/* publ_lists[TIPC_CLUSTER_SCOPE]	*/
  	&publ_node	/* publ_lists[TIPC_NODE_SCOPE]		*/
  };
  
  
  /**
   * 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;
  }
  
  static void named_cluster_distribute(struct sk_buff *buf)
  {
  	struct sk_buff *buf_copy;
  	struct tipc_node *n_ptr;
  
  	list_for_each_entry(n_ptr, &tipc_node_list, list) {
  		if (tipc_node_active_links(n_ptr)) {
  			buf_copy = skb_copy(buf, GFP_ATOMIC);
  			if (!buf_copy)
  				break;
  			msg_set_destnode(buf_msg(buf_copy), n_ptr->addr);
  			tipc_link_send(buf_copy, n_ptr->addr, n_ptr->addr);
  		}
  	}
  
  	kfree_skb(buf);
  }
  
  /**
   * tipc_named_publish - tell other nodes about a new publication by this node
   */
  void tipc_named_publish(struct publication *publ)
  {
  	struct sk_buff *buf;
  	struct distr_item *item;
  
  	list_add_tail(&publ->local_list, &publ_lists[publ->scope]->list);
  	publ_lists[publ->scope]->size++;
  
  	if (publ->scope == TIPC_NODE_SCOPE)
  		return;
  
  	buf = named_prepare_buf(PUBLICATION, ITEM_SIZE, 0);
  	if (!buf) {
  		pr_warn("Publication distribution failure
  ");
  		return;
  	}
  
  	item = (struct distr_item *)msg_data(buf_msg(buf));
  	publ_to_item(item, publ);
  	named_cluster_distribute(buf);
  }
  
  /**
   * tipc_named_withdraw - tell other nodes about a withdrawn publication by this node
   */
  void tipc_named_withdraw(struct publication *publ)
  {
  	struct sk_buff *buf;
  	struct distr_item *item;
  
  	list_del(&publ->local_list);
  	publ_lists[publ->scope]->size--;
  
  	if (publ->scope == TIPC_NODE_SCOPE)
  		return;
  
  	buf = named_prepare_buf(WITHDRAWAL, ITEM_SIZE, 0);
  	if (!buf) {
  		pr_warn("Withdrawal distribution failure
  ");
  		return;
  	}
  
  	item = (struct distr_item *)msg_data(buf_msg(buf));
  	publ_to_item(item, publ);
  	named_cluster_distribute(buf);
  }
  
  /*
   * named_distribute - prepare name info for bulk distribution to another node
   */
  static void named_distribute(struct list_head *message_list, u32 node,
  			     struct publ_list *pls, u32 max_item_buf)
  {
  	struct publication *publ;
  	struct sk_buff *buf = NULL;
  	struct distr_item *item = NULL;
  	u32 left = 0;
  	u32 rest = pls->size * ITEM_SIZE;
  
  	list_for_each_entry(publ, &pls->list, local_list) {
  		if (!buf) {
  			left = (rest <= max_item_buf) ? rest : max_item_buf;
  			rest -= left;
  			buf = named_prepare_buf(PUBLICATION, left, node);
  			if (!buf) {
  				pr_warn("Bulk publication failure
  ");
  				return;
  			}
  			item = (struct distr_item *)msg_data(buf_msg(buf));
  		}
  		publ_to_item(item, publ);
  		item++;
  		left -= ITEM_SIZE;
  		if (!left) {
  			list_add_tail((struct list_head *)buf, message_list);
  			buf = NULL;
  		}
  	}
  }
  
  /**
   * tipc_named_node_up - tell specified node about all publications by this node
   */
  void tipc_named_node_up(unsigned long nodearg)
  {
  	struct tipc_node *n_ptr;
  	struct tipc_link *l_ptr;
  	struct list_head message_list;
  	u32 node = (u32)nodearg;
  	u32 max_item_buf = 0;
  
  	/* compute maximum amount of publication data to send per message */
  	read_lock_bh(&tipc_net_lock);
  	n_ptr = tipc_node_find(node);
  	if (n_ptr) {
  		tipc_node_lock(n_ptr);
  		l_ptr = n_ptr->active_links[0];
  		if (l_ptr)
  			max_item_buf = ((l_ptr->max_pkt - INT_H_SIZE) /
  				ITEM_SIZE) * ITEM_SIZE;
  		tipc_node_unlock(n_ptr);
  	}
  	read_unlock_bh(&tipc_net_lock);
  	if (!max_item_buf)
  		return;
  
  	/* create list of publication messages, then send them as a unit */
  	INIT_LIST_HEAD(&message_list);
  
  	read_lock_bh(&tipc_nametbl_lock);
  	named_distribute(&message_list, node, &publ_cluster, max_item_buf);
  	named_distribute(&message_list, node, &publ_zone, max_item_buf);
  	read_unlock_bh(&tipc_nametbl_lock);
  
  	tipc_link_send_names(&message_list, node);
  }
  
  /**
   * named_purge_publ - 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 named_purge_publ(struct publication *publ)
  {
  	struct publication *p;
  
  	write_lock_bh(&tipc_nametbl_lock);
  	p = tipc_nametbl_remove_publ(publ->type, publ->lower,
  				     publ->node, publ->ref, publ->key);
  	if (p)
  		tipc_nodesub_unsubscribe(&p->subscr);
  	write_unlock_bh(&tipc_nametbl_lock);
  
  	if (p != publ) {
  		pr_err("Unable to remove publication from failed node
  "
  		       " (type=%u, lower=%u, node=0x%x, ref=%u, key=%u)
  ",
  		       publ->type, publ->lower, publ->node, publ->ref,
  		       publ->key);
  	}
  
  	kfree(p);
  }
  
  /**
   * tipc_named_recv - process name table update message sent by another node
   */
  void tipc_named_recv(struct sk_buff *buf)
  {
  	struct publication *publ;
  	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;
  
  	write_lock_bh(&tipc_nametbl_lock);
  	while (count--) {
  		if (msg_type(msg) == PUBLICATION) {
  			publ = tipc_nametbl_insert_publ(ntohl(item->type),
  							ntohl(item->lower),
  							ntohl(item->upper),
  							TIPC_CLUSTER_SCOPE,
  							msg_orignode(msg),
  							ntohl(item->ref),
  							ntohl(item->key));
  			if (publ) {
  				tipc_nodesub_subscribe(&publ->subscr,
  						       msg_orignode(msg),
  						       publ,
  						       (net_ev_handler)
  						       named_purge_publ);
  			}
  		} else if (msg_type(msg) == WITHDRAWAL) {
  			publ = tipc_nametbl_remove_publ(ntohl(item->type),
  							ntohl(item->lower),
  							msg_orignode(msg),
  							ntohl(item->ref),
  							ntohl(item->key));
  
  			if (publ) {
  				tipc_nodesub_unsubscribe(&publ->subscr);
  				kfree(publ);
  			} else {
  				pr_err("Unable to remove publication by node 0x%x
  "
  				       " (type=%u, lower=%u, ref=%u, key=%u)
  ",
  				       msg_orignode(msg), ntohl(item->type),
  				       ntohl(item->lower), ntohl(item->ref),
  				       ntohl(item->key));
  			}
  		} else {
  			pr_warn("Unrecognized name table message received
  ");
  		}
  		item++;
  	}
  	write_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;
  
  	write_lock_bh(&tipc_nametbl_lock);
  
  	for (scope = TIPC_ZONE_SCOPE; scope <= TIPC_NODE_SCOPE; scope++)
  		list_for_each_entry(publ, &publ_lists[scope]->list, local_list)
  			publ->node = tipc_own_addr;
  
  	write_unlock_bh(&tipc_nametbl_lock);
  }