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1 | /* |
2 | * net/tipc/net.c: TIPC network routing code |
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 "net.h" |
39 | #include "name_distr.h" |
40 | #include "subscr.h" |
41 | #include "port.h" |
42 | #include "node.h" |
43 | #include "config.h" |
44 | |
45 | /* |
46 | * The TIPC locking policy is designed to ensure a very fine locking |
47 | * granularity, permitting complete parallel access to individual |
48 | * port and node/link instances. The code consists of three major |
49 | * locking domains, each protected with their own disjunct set of locks. |
50 | * |
51 | * 1: The routing hierarchy. |
52 | * Comprises the structures 'zone', 'cluster', 'node', 'link' |
53 | * and 'bearer'. The whole hierarchy is protected by a big |
54 | * read/write lock, tipc_net_lock, to enssure that nothing is added |
55 | * or removed while code is accessing any of these structures. |
56 | * This layer must not be called from the two others while they |
57 | * hold any of their own locks. |
58 | * Neither must it itself do any upcalls to the other two before |
59 | * it has released tipc_net_lock and other protective locks. |
60 | * |
61 | * Within the tipc_net_lock domain there are two sub-domains;'node' and |
62 | * 'bearer', where local write operations are permitted, |
63 | * provided that those are protected by individual spin_locks |
64 | * per instance. Code holding tipc_net_lock(read) and a node spin_lock |
65 | * is permitted to poke around in both the node itself and its |
66 | * subordinate links. I.e, it can update link counters and queues, |
67 | * change link state, send protocol messages, and alter the |
68 | * "active_links" array in the node; but it can _not_ remove a link |
69 | * or a node from the overall structure. |
70 | * Correspondingly, individual bearers may change status within a |
71 | * tipc_net_lock(read), protected by an individual spin_lock ber bearer |
72 | * instance, but it needs tipc_net_lock(write) to remove/add any bearers. |
73 | * |
74 | * |
75 | * 2: The transport level of the protocol. |
76 | * This consists of the structures port, (and its user level |
77 | * representations, such as user_port and tipc_sock), reference and |
78 | * tipc_user (port.c, reg.c, socket.c). |
79 | * |
80 | * This layer has four different locks: |
81 | * - The tipc_port spin_lock. This is protecting each port instance |
82 | * from parallel data access and removal. Since we can not place |
83 | * this lock in the port itself, it has been placed in the |
84 | * corresponding reference table entry, which has the same life |
85 | * cycle as the module. This entry is difficult to access from |
86 | * outside the TIPC core, however, so a pointer to the lock has |
87 | * been added in the port instance, -to be used for unlocking |
88 | * only. |
89 | * - A read/write lock to protect the reference table itself (teg.c). |
90 | * (Nobody is using read-only access to this, so it can just as |
91 | * well be changed to a spin_lock) |
92 | * - A spin lock to protect the registry of kernel/driver users (reg.c) |
93 | * - A global spin_lock (tipc_port_lock), which only task is to ensure |
94 | * consistency where more than one port is involved in an operation, |
95 | * i.e., whe a port is part of a linked list of ports. |
96 | * There are two such lists; 'port_list', which is used for management, |
97 | * and 'wait_list', which is used to queue ports during congestion. |
98 | * |
99 | * 3: The name table (name_table.c, name_distr.c, subscription.c) |
100 | * - There is one big read/write-lock (tipc_nametbl_lock) protecting the |
101 | * overall name table structure. Nothing must be added/removed to |
102 | * this structure without holding write access to it. |
103 | * - There is one local spin_lock per sub_sequence, which can be seen |
104 | * as a sub-domain to the tipc_nametbl_lock domain. It is used only |
105 | * for translation operations, and is needed because a translation |
106 | * steps the root of the 'publication' linked list between each lookup. |
107 | * This is always used within the scope of a tipc_nametbl_lock(read). |
108 | * - A local spin_lock protecting the queue of subscriber events. |
109 | */ |
110 | |
111 | DEFINE_RWLOCK(tipc_net_lock); |
112 | |
113 | static void net_route_named_msg(struct sk_buff *buf) |
114 | { |
115 | struct tipc_msg *msg = buf_msg(buf); |
116 | u32 dnode; |
117 | u32 dport; |
118 | |
119 | if (!msg_named(msg)) { |
120 | kfree_skb(buf); |
121 | return; |
122 | } |
123 | |
124 | dnode = addr_domain(msg_lookup_scope(msg)); |
125 | dport = tipc_nametbl_translate(msg_nametype(msg), msg_nameinst(msg), &dnode); |
126 | if (dport) { |
127 | msg_set_destnode(msg, dnode); |
128 | msg_set_destport(msg, dport); |
129 | tipc_net_route_msg(buf); |
130 | return; |
131 | } |
132 | tipc_reject_msg(buf, TIPC_ERR_NO_NAME); |
133 | } |
134 | |
135 | void tipc_net_route_msg(struct sk_buff *buf) |
136 | { |
137 | struct tipc_msg *msg; |
138 | u32 dnode; |
139 | |
140 | if (!buf) |
141 | return; |
142 | msg = buf_msg(buf); |
143 | |
144 | /* Handle message for this node */ |
145 | dnode = msg_short(msg) ? tipc_own_addr : msg_destnode(msg); |
146 | if (tipc_in_scope(dnode, tipc_own_addr)) { |
147 | if (msg_isdata(msg)) { |
148 | if (msg_mcast(msg)) |
149 | tipc_port_recv_mcast(buf, NULL); |
150 | else if (msg_destport(msg)) |
151 | tipc_port_recv_msg(buf); |
152 | else |
153 | net_route_named_msg(buf); |
154 | return; |
155 | } |
156 | switch (msg_user(msg)) { |
157 | case NAME_DISTRIBUTOR: |
158 | tipc_named_recv(buf); |
159 | break; |
160 | case CONN_MANAGER: |
161 | tipc_port_recv_proto_msg(buf); |
162 | break; |
163 | default: |
164 | kfree_skb(buf); |
165 | } |
166 | return; |
167 | } |
168 | |
169 | /* Handle message for another node */ |
170 | skb_trim(buf, msg_size(msg)); |
171 | tipc_link_send(buf, dnode, msg_link_selector(msg)); |
172 | } |
173 | |
174 | void tipc_net_start(u32 addr) |
175 | { |
176 | char addr_string[16]; |
177 | |
178 | write_lock_bh(&tipc_net_lock); |
179 | tipc_own_addr = addr; |
180 | tipc_named_reinit(); |
181 | tipc_port_reinit(); |
182 | tipc_bclink_init(); |
183 | write_unlock_bh(&tipc_net_lock); |
184 | |
185 | tipc_cfg_reinit(); |
186 | |
187 | pr_info("Started in network mode\n"); |
188 | pr_info("Own node address %s, network identity %u\n", |
189 | tipc_addr_string_fill(addr_string, tipc_own_addr), tipc_net_id); |
190 | } |
191 | |
192 | void tipc_net_stop(void) |
193 | { |
194 | struct tipc_node *node, *t_node; |
195 | |
196 | if (!tipc_own_addr) |
197 | return; |
198 | write_lock_bh(&tipc_net_lock); |
199 | tipc_bearer_stop(); |
200 | tipc_bclink_stop(); |
201 | list_for_each_entry_safe(node, t_node, &tipc_node_list, list) |
202 | tipc_node_delete(node); |
203 | write_unlock_bh(&tipc_net_lock); |
204 | pr_info("Left network mode\n"); |
205 | } |
206 |
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