Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
net.c
Go to the documentation of this file.
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  }
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))
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:
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 
175 {
176  char addr_string[16];
177 
179  tipc_own_addr = addr;
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;
202  tipc_node_delete(node);
204  pr_info("Left network mode\n");
205 }