| 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 | void tipc_net_start(u32 addr) |
| 168 | { |
| 169 | char addr_string[16]; |
| 170 | |
| 171 | tipc_own_addr = addr; |
| 172 | tipc_named_reinit(); |
| 173 | tipc_port_reinit(); |
| 174 | tipc_bclink_init(); |
| 175 | tipc_nametbl_publish(TIPC_CFG_SRV, tipc_own_addr, tipc_own_addr, |
| 176 | TIPC_ZONE_SCOPE, 0, tipc_own_addr); |
| 177 | |
| 178 | pr_info("Started in network mode\n"); |
| 179 | pr_info("Own node address %s, network identity %u\n", |
| 180 | tipc_addr_string_fill(addr_string, tipc_own_addr), tipc_net_id); |
| 181 | } |
| 182 | |
| 183 | void tipc_net_stop(void) |
| 184 | { |
| 185 | if (!tipc_own_addr) |
| 186 | return; |
| 187 | |
| 188 | tipc_nametbl_withdraw(TIPC_CFG_SRV, tipc_own_addr, 0, tipc_own_addr); |
| 189 | rtnl_lock(); |
| 190 | tipc_bearer_stop(); |
| 191 | tipc_bclink_stop(); |
| 192 | tipc_node_stop(); |
| 193 | rtnl_unlock(); |
| 194 | |
| 195 | pr_info("Left network mode\n"); |
| 196 | } |