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 
tipc_nodesub_subscribe(struct tipc_node_subscr * node_sub,u32 addr,void * usr_handle,net_ev_handler handle_down)45 void tipc_nodesub_subscribe(struct tipc_node_subscr *node_sub, u32 addr,
46 		       void *usr_handle, net_ev_handler handle_down)
47 {
48 	if (addr == tipc_own_addr) {
49 		node_sub->node = NULL;
50 		return;
51 	}
52 
53 	node_sub->node = tipc_node_find(addr);
54 	if (!node_sub->node) {
55 		warn("Node subscription rejected, unknown node 0x%x\n", 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 
tipc_nodesub_unsubscribe(struct tipc_node_subscr * node_sub)70 void tipc_nodesub_unsubscribe(struct tipc_node_subscr *node_sub)
71 {
72 	if (!node_sub->node)
73 		return;
74 
75 	tipc_node_lock(node_sub->node);
76 	list_del_init(&node_sub->nodesub_list);
77 	tipc_node_unlock(node_sub->node);
78 }
79 
80 /**
81  * tipc_nodesub_notify - notify subscribers that a node is unreachable
82  *
83  * Note: node is locked by caller
84  */
85 
tipc_nodesub_notify(struct tipc_node * node)86 void tipc_nodesub_notify(struct tipc_node *node)
87 {
88 	struct tipc_node_subscr *ns;
89 
90 	list_for_each_entry(ns, &node->nsub, nodesub_list) {
91 		if (ns->handle_node_down) {
92 			tipc_k_signal((Handler)ns->handle_node_down,
93 				      (unsigned long)ns->usr_handle);
94 			ns->handle_node_down = NULL;
95 		}
96 	}
97 }
98