1 /* 2 * net/tipc/net.c: TIPC network routing code 3 * 4 * Copyright (c) 1995-2006, 2014, 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 "socket.h" 43 #include "node.h" 44 #include "config.h" 45 46 /* 47 * The TIPC locking policy is designed to ensure a very fine locking 48 * granularity, permitting complete parallel access to individual 49 * port and node/link instances. The code consists of four major 50 * locking domains, each protected with their own disjunct set of locks. 51 * 52 * 1: The bearer level. 53 * RTNL lock is used to serialize the process of configuring bearer 54 * on update side, and RCU lock is applied on read side to make 55 * bearer instance valid on both paths of message transmission and 56 * reception. 57 * 58 * 2: The node and link level. 59 * All node instances are saved into two tipc_node_list and node_htable 60 * lists. The two lists are protected by node_list_lock on write side, 61 * and they are guarded with RCU lock on read side. Especially node 62 * instance is destroyed only when TIPC module is removed, and we can 63 * confirm that there has no any user who is accessing the node at the 64 * moment. Therefore, Except for iterating the two lists within RCU 65 * protection, it's no needed to hold RCU that we access node instance 66 * in other places. 67 * 68 * In addition, all members in node structure including link instances 69 * are protected by node spin lock. 70 * 71 * 3: The transport level of the protocol. 72 * This consists of the structures port, (and its user level 73 * representations, such as user_port and tipc_sock), reference and 74 * tipc_user (port.c, reg.c, socket.c). 75 * 76 * This layer has four different locks: 77 * - The tipc_port spin_lock. This is protecting each port instance 78 * from parallel data access and removal. Since we can not place 79 * this lock in the port itself, it has been placed in the 80 * corresponding reference table entry, which has the same life 81 * cycle as the module. This entry is difficult to access from 82 * outside the TIPC core, however, so a pointer to the lock has 83 * been added in the port instance, -to be used for unlocking 84 * only. 85 * - A read/write lock to protect the reference table itself (teg.c). 86 * (Nobody is using read-only access to this, so it can just as 87 * well be changed to a spin_lock) 88 * - A spin lock to protect the registry of kernel/driver users (reg.c) 89 * - A global spin_lock (tipc_port_lock), which only task is to ensure 90 * consistency where more than one port is involved in an operation, 91 * i.e., whe a port is part of a linked list of ports. 92 * There are two such lists; 'port_list', which is used for management, 93 * and 'wait_list', which is used to queue ports during congestion. 94 * 95 * 4: The name table (name_table.c, name_distr.c, subscription.c) 96 * - There is one big read/write-lock (tipc_nametbl_lock) protecting the 97 * overall name table structure. Nothing must be added/removed to 98 * this structure without holding write access to it. 99 * - There is one local spin_lock per sub_sequence, which can be seen 100 * as a sub-domain to the tipc_nametbl_lock domain. It is used only 101 * for translation operations, and is needed because a translation 102 * steps the root of the 'publication' linked list between each lookup. 103 * This is always used within the scope of a tipc_nametbl_lock(read). 104 * - A local spin_lock protecting the queue of subscriber events. 105 */ 106 107 int tipc_net_start(u32 addr) 108 { 109 char addr_string[16]; 110 int res; 111 112 tipc_own_addr = addr; 113 tipc_named_reinit(); 114 tipc_port_reinit(); 115 res = tipc_bclink_init(); 116 if (res) 117 return res; 118 119 tipc_nametbl_publish(TIPC_CFG_SRV, tipc_own_addr, tipc_own_addr, 120 TIPC_ZONE_SCOPE, 0, tipc_own_addr); 121 122 pr_info("Started in network mode\n"); 123 pr_info("Own node address %s, network identity %u\n", 124 tipc_addr_string_fill(addr_string, tipc_own_addr), tipc_net_id); 125 return 0; 126 } 127 128 void tipc_net_stop(void) 129 { 130 if (!tipc_own_addr) 131 return; 132 133 tipc_nametbl_withdraw(TIPC_CFG_SRV, tipc_own_addr, 0, tipc_own_addr); 134 rtnl_lock(); 135 tipc_bearer_stop(); 136 tipc_bclink_stop(); 137 tipc_node_stop(); 138 rtnl_unlock(); 139 140 pr_info("Left network mode\n"); 141 } 142