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 "socket.h" 42 #include "node.h" 43 #include "bcast.h" 44 #include "netlink.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(struct net *net, u32 addr) 108 { 109 struct tipc_net *tn = net_generic(net, tipc_net_id); 110 char addr_string[16]; 111 112 tn->own_addr = addr; 113 114 /* Ensure that the new address is visible before we reinit. */ 115 smp_mb(); 116 117 tipc_named_reinit(net); 118 tipc_sk_reinit(net); 119 120 tipc_nametbl_publish(net, TIPC_CFG_SRV, tn->own_addr, tn->own_addr, 121 TIPC_ZONE_SCOPE, 0, tn->own_addr); 122 123 pr_info("Started in network mode\n"); 124 pr_info("Own node address %s, network identity %u\n", 125 tipc_addr_string_fill(addr_string, tn->own_addr), 126 tn->net_id); 127 return 0; 128 } 129 130 void tipc_net_stop(struct net *net) 131 { 132 struct tipc_net *tn = net_generic(net, tipc_net_id); 133 134 if (!tn->own_addr) 135 return; 136 137 tipc_nametbl_withdraw(net, TIPC_CFG_SRV, tn->own_addr, 0, 138 tn->own_addr); 139 rtnl_lock(); 140 tipc_bearer_stop(net); 141 tipc_node_stop(net); 142 rtnl_unlock(); 143 144 pr_info("Left network mode\n"); 145 } 146 147 static int __tipc_nl_add_net(struct net *net, struct tipc_nl_msg *msg) 148 { 149 struct tipc_net *tn = net_generic(net, tipc_net_id); 150 void *hdr; 151 struct nlattr *attrs; 152 153 hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family, 154 NLM_F_MULTI, TIPC_NL_NET_GET); 155 if (!hdr) 156 return -EMSGSIZE; 157 158 attrs = nla_nest_start(msg->skb, TIPC_NLA_NET); 159 if (!attrs) 160 goto msg_full; 161 162 if (nla_put_u32(msg->skb, TIPC_NLA_NET_ID, tn->net_id)) 163 goto attr_msg_full; 164 165 nla_nest_end(msg->skb, attrs); 166 genlmsg_end(msg->skb, hdr); 167 168 return 0; 169 170 attr_msg_full: 171 nla_nest_cancel(msg->skb, attrs); 172 msg_full: 173 genlmsg_cancel(msg->skb, hdr); 174 175 return -EMSGSIZE; 176 } 177 178 int tipc_nl_net_dump(struct sk_buff *skb, struct netlink_callback *cb) 179 { 180 struct net *net = sock_net(skb->sk); 181 int err; 182 int done = cb->args[0]; 183 struct tipc_nl_msg msg; 184 185 if (done) 186 return 0; 187 188 msg.skb = skb; 189 msg.portid = NETLINK_CB(cb->skb).portid; 190 msg.seq = cb->nlh->nlmsg_seq; 191 192 err = __tipc_nl_add_net(net, &msg); 193 if (err) 194 goto out; 195 196 done = 1; 197 out: 198 cb->args[0] = done; 199 200 return skb->len; 201 } 202 203 int tipc_nl_net_set(struct sk_buff *skb, struct genl_info *info) 204 { 205 struct net *net = sock_net(skb->sk); 206 struct tipc_net *tn = net_generic(net, tipc_net_id); 207 struct nlattr *attrs[TIPC_NLA_NET_MAX + 1]; 208 int err; 209 210 if (!info->attrs[TIPC_NLA_NET]) 211 return -EINVAL; 212 213 err = nla_parse_nested(attrs, TIPC_NLA_NET_MAX, 214 info->attrs[TIPC_NLA_NET], tipc_nl_net_policy, 215 info->extack); 216 if (err) 217 return err; 218 219 if (attrs[TIPC_NLA_NET_ID]) { 220 u32 val; 221 222 /* Can't change net id once TIPC has joined a network */ 223 if (tn->own_addr) 224 return -EPERM; 225 226 val = nla_get_u32(attrs[TIPC_NLA_NET_ID]); 227 if (val < 1 || val > 9999) 228 return -EINVAL; 229 230 tn->net_id = val; 231 } 232 233 if (attrs[TIPC_NLA_NET_ADDR]) { 234 u32 addr; 235 236 /* Can't change net addr once TIPC has joined a network */ 237 if (tn->own_addr) 238 return -EPERM; 239 240 addr = nla_get_u32(attrs[TIPC_NLA_NET_ADDR]); 241 if (!tipc_addr_node_valid(addr)) 242 return -EINVAL; 243 244 rtnl_lock(); 245 tipc_net_start(net, addr); 246 rtnl_unlock(); 247 } 248 249 return 0; 250 } 251