net/tipc/node_subscr.c

   1 /*
   2  * net/tipc/node_subscr.c: TIPC "node down" subscription handling
   3  *
   4  * Copyright (c) 1995-2006, Ericsson AB
   5  * Copyright (c) 2005, 2010-2011, Wind River Systems
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the names of the copyright holders nor the names of its
  17  *    contributors may be used to endorse or promote products derived from
  18  *    this software without specific prior written permission.
  19  *
  20  * Alternatively, this software may be distributed under the terms of the
  21  * GNU General Public License ("GPL") version 2 as published by the Free
  22  * Software Foundation.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "core.h"
  38 #include "node_subscr.h"
  39 #include "node.h"
  40
  41 /**
  42  * tipc_nodesub_subscribe - create "node down" subscription for specified node
  43  */
  44 void tipc_nodesub_subscribe(struct tipc_node_subscr *node_sub, u32 addr,
  45                        void *usr_handle, net_ev_handler handle_down)
  46 {
  47         if (in_own_node(addr)) {
  48                 node_sub->node = NULL;
  49                 return;
  50         }
  51
  52         node_sub->node = tipc_node_find(addr);
  53         if (!node_sub->node) {
  54                 pr_warn("Node subscription rejected, unknown node 0x%x\n",
  55                         addr);
  56                 return;
  57         }
  58         node_sub->handle_node_down = handle_down;
  59         node_sub->usr_handle = usr_handle;
  60
  61         tipc_node_lock(node_sub->node);
  62         list_add_tail(&node_sub->nodesub_list, &node_sub->node->nsub);
  63         tipc_node_unlock(node_sub->node);
  64 }
  65
  66 /**
  67  * tipc_nodesub_unsubscribe - cancel "node down" subscription (if any)
  68  */
  69 void tipc_nodesub_unsubscribe(struct tipc_node_subscr *node_sub)
  70 {
  71         if (!node_sub->node)
  72                 return;
  73
  74         tipc_node_lock(node_sub->node);
  75         list_del_init(&node_sub->nodesub_list);
  76         tipc_node_unlock(node_sub->node);
  77 }
  78
  79 /**
  80  * tipc_nodesub_notify - notify subscribers that a node is unreachable
  81  *
  82  * Note: node is locked by caller
  83  */
  84 void tipc_nodesub_notify(struct tipc_node *node)
  85 {
  86         struct tipc_node_subscr *ns;
  87
  88         list_for_each_entry(ns, &node->nsub, nodesub_list) {
  89                 if (ns->handle_node_down) {
  90                         tipc_k_signal((Handler)ns->handle_node_down,
  91                                       (unsigned long)ns->usr_handle);
  92                         ns->handle_node_down = NULL;
  93                 }
  94         }
  95 }