1 /* 2 * net/tipc/net.c: TIPC network routing code 3 * 4 * Copyright (c) 1995-2006, Ericsson AB 5 * Copyright (c) 2005, 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 "config.h" 43 44 /* 45 * The TIPC locking policy is designed to ensure a very fine locking 46 * granularity, permitting complete parallel access to individual 47 * port and node/link instances. The code consists of three major 48 * locking domains, each protected with their own disjunct set of locks. 49 * 50 * 1: The routing hierarchy. 51 * Comprises the structures 'zone', 'cluster', 'node', 'link' 52 * and 'bearer'. The whole hierarchy is protected by a big 53 * read/write lock, tipc_net_lock, to enssure that nothing is added 54 * or removed while code is accessing any of these structures. 55 * This layer must not be called from the two others while they 56 * hold any of their own locks. 57 * Neither must it itself do any upcalls to the other two before 58 * it has released tipc_net_lock and other protective locks. 59 * 60 * Within the tipc_net_lock domain there are two sub-domains;'node' and 61 * 'bearer', where local write operations are permitted, 62 * provided that those are protected by individual spin_locks 63 * per instance. Code holding tipc_net_lock(read) and a node spin_lock 64 * is permitted to poke around in both the node itself and its 65 * subordinate links. I.e, it can update link counters and queues, 66 * change link state, send protocol messages, and alter the 67 * "active_links" array in the node; but it can _not_ remove a link 68 * or a node from the overall structure. 69 * Correspondingly, individual bearers may change status within a 70 * tipc_net_lock(read), protected by an individual spin_lock ber bearer 71 * instance, but it needs tipc_net_lock(write) to remove/add any bearers. 72 * 73 * 74 * 2: The transport level of the protocol. 75 * This consists of the structures port, (and its user level 76 * representations, such as user_port and tipc_sock), reference and 77 * tipc_user (port.c, reg.c, socket.c). 78 * 79 * This layer has four different locks: 80 * - The tipc_port spin_lock. This is protecting each port instance 81 * from parallel data access and removal. Since we can not place 82 * this lock in the port itself, it has been placed in the 83 * corresponding reference table entry, which has the same life 84 * cycle as the module. This entry is difficult to access from 85 * outside the TIPC core, however, so a pointer to the lock has 86 * been added in the port instance, -to be used for unlocking 87 * only. 88 * - A read/write lock to protect the reference table itself (teg.c). 89 * (Nobody is using read-only access to this, so it can just as 90 * well be changed to a spin_lock) 91 * - A spin lock to protect the registry of kernel/driver users (reg.c) 92 * - A global spin_lock (tipc_port_lock), which only task is to ensure 93 * consistency where more than one port is involved in an operation, 94 * i.e., whe a port is part of a linked list of ports. 95 * There are two such lists; 'port_list', which is used for management, 96 * and 'wait_list', which is used to queue ports during congestion. 97 * 98 * 3: The name table (name_table.c, name_distr.c, subscription.c) 99 * - There is one big read/write-lock (tipc_nametbl_lock) protecting the 100 * overall name table structure. Nothing must be added/removed to 101 * this structure without holding write access to it. 102 * - There is one local spin_lock per sub_sequence, which can be seen 103 * as a sub-domain to the tipc_nametbl_lock domain. It is used only 104 * for translation operations, and is needed because a translation 105 * steps the root of the 'publication' linked list between each lookup. 106 * This is always used within the scope of a tipc_nametbl_lock(read). 107 * - A local spin_lock protecting the queue of subscriber events. 108 */ 109 110 DEFINE_RWLOCK(tipc_net_lock); 111 struct network tipc_net; 112 113 static int net_start(void) 114 { 115 tipc_net.nodes = kcalloc(tipc_max_nodes + 1, 116 sizeof(*tipc_net.nodes), GFP_ATOMIC); 117 tipc_net.highest_node = 0; 118 119 return tipc_net.nodes ? 0 : -ENOMEM; 120 } 121 122 static void net_stop(void) 123 { 124 u32 n_num; 125 126 for (n_num = 1; n_num <= tipc_net.highest_node; n_num++) 127 tipc_node_delete(tipc_net.nodes[n_num]); 128 kfree(tipc_net.nodes); 129 tipc_net.nodes = NULL; 130 } 131 132 static void net_route_named_msg(struct sk_buff *buf) 133 { 134 struct tipc_msg *msg = buf_msg(buf); 135 u32 dnode; 136 u32 dport; 137 138 if (!msg_named(msg)) { 139 buf_discard(buf); 140 return; 141 } 142 143 dnode = addr_domain(msg_lookup_scope(msg)); 144 dport = tipc_nametbl_translate(msg_nametype(msg), msg_nameinst(msg), &dnode); 145 if (dport) { 146 msg_set_destnode(msg, dnode); 147 msg_set_destport(msg, dport); 148 tipc_net_route_msg(buf); 149 return; 150 } 151 tipc_reject_msg(buf, TIPC_ERR_NO_NAME); 152 } 153 154 void tipc_net_route_msg(struct sk_buff *buf) 155 { 156 struct tipc_msg *msg; 157 u32 dnode; 158 159 if (!buf) 160 return; 161 msg = buf_msg(buf); 162 163 msg_incr_reroute_cnt(msg); 164 if (msg_reroute_cnt(msg) > 6) { 165 if (msg_errcode(msg)) { 166 buf_discard(buf); 167 } else { 168 tipc_reject_msg(buf, msg_destport(msg) ? 169 TIPC_ERR_NO_PORT : TIPC_ERR_NO_NAME); 170 } 171 return; 172 } 173 174 /* Handle message for this node */ 175 dnode = msg_short(msg) ? tipc_own_addr : msg_destnode(msg); 176 if (tipc_in_scope(dnode, tipc_own_addr)) { 177 if (msg_isdata(msg)) { 178 if (msg_mcast(msg)) 179 tipc_port_recv_mcast(buf, NULL); 180 else if (msg_destport(msg)) 181 tipc_port_recv_msg(buf); 182 else 183 net_route_named_msg(buf); 184 return; 185 } 186 switch (msg_user(msg)) { 187 case NAME_DISTRIBUTOR: 188 tipc_named_recv(buf); 189 break; 190 case CONN_MANAGER: 191 tipc_port_recv_proto_msg(buf); 192 break; 193 default: 194 buf_discard(buf); 195 } 196 return; 197 } 198 199 /* Handle message for another node */ 200 skb_trim(buf, msg_size(msg)); 201 tipc_link_send(buf, dnode, msg_link_selector(msg)); 202 } 203 204 int tipc_net_start(u32 addr) 205 { 206 char addr_string[16]; 207 int res; 208 209 if (tipc_mode != TIPC_NODE_MODE) 210 return -ENOPROTOOPT; 211 212 tipc_subscr_stop(); 213 tipc_cfg_stop(); 214 215 tipc_own_addr = addr; 216 tipc_mode = TIPC_NET_MODE; 217 tipc_named_reinit(); 218 tipc_port_reinit(); 219 220 res = net_start(); 221 if (res) 222 return res; 223 res = tipc_bclink_init(); 224 if (res) 225 return res; 226 227 tipc_k_signal((Handler)tipc_subscr_start, 0); 228 tipc_k_signal((Handler)tipc_cfg_init, 0); 229 230 info("Started in network mode\n"); 231 info("Own node address %s, network identity %u\n", 232 tipc_addr_string_fill(addr_string, tipc_own_addr), tipc_net_id); 233 return 0; 234 } 235 236 void tipc_net_stop(void) 237 { 238 if (tipc_mode != TIPC_NET_MODE) 239 return; 240 write_lock_bh(&tipc_net_lock); 241 tipc_bearer_stop(); 242 tipc_mode = TIPC_NODE_MODE; 243 tipc_bclink_stop(); 244 net_stop(); 245 write_unlock_bh(&tipc_net_lock); 246 info("Left network mode\n"); 247 } 248 249