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 four major 49 * locking domains, each protected with their own disjunct set of locks. 50 * 51 * 1: The bearer level. 52 * RTNL lock is used to serialize the process of configuring bearer 53 * on update side, and RCU lock is applied on read side to make 54 * bearer instance valid on both paths of message transmission and 55 * reception. 56 * 57 * 2: The node and link level. 58 * All node instances are saved into two tipc_node_list and node_htable 59 * lists. The two lists are protected by node_list_lock on write side, 60 * and they are guarded with RCU lock on read side. Especially node 61 * instance is destroyed only when TIPC module is removed, and we can 62 * confirm that there has no any user who is accessing the node at the 63 * moment. Therefore, Except for iterating the two lists within RCU 64 * protection, it's no needed to hold RCU that we access node instance 65 * in other places. 66 * 67 * In addition, all members in node structure including link instances 68 * are protected by node spin lock. 69 * 70 * 3: The transport level of the protocol. 71 * This consists of the structures port, (and its user level 72 * representations, such as user_port and tipc_sock), reference and 73 * tipc_user (port.c, reg.c, socket.c). 74 * 75 * This layer has four different locks: 76 * - The tipc_port spin_lock. This is protecting each port instance 77 * from parallel data access and removal. Since we can not place 78 * this lock in the port itself, it has been placed in the 79 * corresponding reference table entry, which has the same life 80 * cycle as the module. This entry is difficult to access from 81 * outside the TIPC core, however, so a pointer to the lock has 82 * been added in the port instance, -to be used for unlocking 83 * only. 84 * - A read/write lock to protect the reference table itself (teg.c). 85 * (Nobody is using read-only access to this, so it can just as 86 * well be changed to a spin_lock) 87 * - A spin lock to protect the registry of kernel/driver users (reg.c) 88 * - A global spin_lock (tipc_port_lock), which only task is to ensure 89 * consistency where more than one port is involved in an operation, 90 * i.e., whe a port is part of a linked list of ports. 91 * There are two such lists; 'port_list', which is used for management, 92 * and 'wait_list', which is used to queue ports during congestion. 93 * 94 * 4: The name table (name_table.c, name_distr.c, subscription.c) 95 * - There is one big read/write-lock (tipc_nametbl_lock) protecting the 96 * overall name table structure. Nothing must be added/removed to 97 * this structure without holding write access to it. 98 * - There is one local spin_lock per sub_sequence, which can be seen 99 * as a sub-domain to the tipc_nametbl_lock domain. It is used only 100 * for translation operations, and is needed because a translation 101 * steps the root of the 'publication' linked list between each lookup. 102 * This is always used within the scope of a tipc_nametbl_lock(read). 103 * - A local spin_lock protecting the queue of subscriber events. 104 */ 105 106 static void net_route_named_msg(struct sk_buff *buf) 107 { 108 struct tipc_msg *msg = buf_msg(buf); 109 u32 dnode; 110 u32 dport; 111 112 if (!msg_named(msg)) { 113 kfree_skb(buf); 114 return; 115 } 116 117 dnode = addr_domain(msg_lookup_scope(msg)); 118 dport = tipc_nametbl_translate(msg_nametype(msg), msg_nameinst(msg), &dnode); 119 if (dport) { 120 msg_set_destnode(msg, dnode); 121 msg_set_destport(msg, dport); 122 tipc_net_route_msg(buf); 123 return; 124 } 125 tipc_reject_msg(buf, TIPC_ERR_NO_NAME); 126 } 127 128 void tipc_net_route_msg(struct sk_buff *buf) 129 { 130 struct tipc_msg *msg; 131 u32 dnode; 132 133 if (!buf) 134 return; 135 msg = buf_msg(buf); 136 137 /* Handle message for this node */ 138 dnode = msg_short(msg) ? tipc_own_addr : msg_destnode(msg); 139 if (tipc_in_scope(dnode, tipc_own_addr)) { 140 if (msg_isdata(msg)) { 141 if (msg_mcast(msg)) 142 tipc_port_mcast_rcv(buf, NULL); 143 else if (msg_destport(msg)) 144 tipc_port_rcv(buf); 145 else 146 net_route_named_msg(buf); 147 return; 148 } 149 switch (msg_user(msg)) { 150 case NAME_DISTRIBUTOR: 151 tipc_named_rcv(buf); 152 break; 153 case CONN_MANAGER: 154 tipc_port_proto_rcv(buf); 155 break; 156 default: 157 kfree_skb(buf); 158 } 159 return; 160 } 161 162 /* Handle message for another node */ 163 skb_trim(buf, msg_size(msg)); 164 tipc_link_xmit(buf, dnode, msg_link_selector(msg)); 165 } 166 167 int tipc_net_start(u32 addr) 168 { 169 char addr_string[16]; 170 int res; 171 172 tipc_own_addr = addr; 173 tipc_named_reinit(); 174 tipc_port_reinit(); 175 res = tipc_bclink_init(); 176 if (res) 177 return res; 178 179 tipc_nametbl_publish(TIPC_CFG_SRV, tipc_own_addr, tipc_own_addr, 180 TIPC_ZONE_SCOPE, 0, tipc_own_addr); 181 182 pr_info("Started in network mode\n"); 183 pr_info("Own node address %s, network identity %u\n", 184 tipc_addr_string_fill(addr_string, tipc_own_addr), tipc_net_id); 185 return 0; 186 } 187 188 void tipc_net_stop(void) 189 { 190 if (!tipc_own_addr) 191 return; 192 193 tipc_nametbl_withdraw(TIPC_CFG_SRV, tipc_own_addr, 0, tipc_own_addr); 194 rtnl_lock(); 195 tipc_bearer_stop(); 196 tipc_bclink_stop(); 197 tipc_node_stop(); 198 rtnl_unlock(); 199 200 pr_info("Left network mode\n"); 201 } 202