net/tipc/net.c

   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 #include "monitor.h"
  46
  47 /*
  48  * The TIPC locking policy is designed to ensure a very fine locking
  49  * granularity, permitting complete parallel access to individual
  50  * port and node/link instances. The code consists of four major
  51  * locking domains, each protected with their own disjunct set of locks.
  52  *
  53  * 1: The bearer level.
  54  *    RTNL lock is used to serialize the process of configuring bearer
  55  *    on update side, and RCU lock is applied on read side to make
  56  *    bearer instance valid on both paths of message transmission and
  57  *    reception.
  58  *
  59  * 2: The node and link level.
  60  *    All node instances are saved into two tipc_node_list and node_htable
  61  *    lists. The two lists are protected by node_list_lock on write side,
  62  *    and they are guarded with RCU lock on read side. Especially node
  63  *    instance is destroyed only when TIPC module is removed, and we can
  64  *    confirm that there has no any user who is accessing the node at the
  65  *    moment. Therefore, Except for iterating the two lists within RCU
  66  *    protection, it's no needed to hold RCU that we access node instance
  67  *    in other places.
  68  *
  69  *    In addition, all members in node structure including link instances
  70  *    are protected by node spin lock.
  71  *
  72  * 3: The transport level of the protocol.
  73  *    This consists of the structures port, (and its user level
  74  *    representations, such as user_port and tipc_sock), reference and
  75  *    tipc_user (port.c, reg.c, socket.c).
  76  *
  77  *    This layer has four different locks:
  78  *     - The tipc_port spin_lock. This is protecting each port instance
  79  *       from parallel data access and removal. Since we can not place
  80  *       this lock in the port itself, it has been placed in the
  81  *       corresponding reference table entry, which has the same life
  82  *       cycle as the module. This entry is difficult to access from
  83  *       outside the TIPC core, however, so a pointer to the lock has
  84  *       been added in the port instance, -to be used for unlocking
  85  *       only.
  86  *     - A read/write lock to protect the reference table itself (teg.c).
  87  *       (Nobody is using read-only access to this, so it can just as
  88  *       well be changed to a spin_lock)
  89  *     - A spin lock to protect the registry of kernel/driver users (reg.c)
  90  *     - A global spin_lock (tipc_port_lock), which only task is to ensure
  91  *       consistency where more than one port is involved in an operation,
  92  *       i.e., when a port is part of a linked list of ports.
  93  *       There are two such lists; 'port_list', which is used for management,
  94  *       and 'wait_list', which is used to queue ports during congestion.
  95  *
  96  *  4: The name table (name_table.c, name_distr.c, subscription.c)
  97  *     - There is one big read/write-lock (tipc_nametbl_lock) protecting the
  98  *       overall name table structure. Nothing must be added/removed to
  99  *       this structure without holding write access to it.
 100  *     - There is one local spin_lock per sub_sequence, which can be seen
 101  *       as a sub-domain to the tipc_nametbl_lock domain. It is used only
 102  *       for translation operations, and is needed because a translation
 103  *       steps the root of the 'publication' linked list between each lookup.
 104  *       This is always used within the scope of a tipc_nametbl_lock(read).
 105  *     - A local spin_lock protecting the queue of subscriber events.
 106 */
 107
 108 static void tipc_net_finalize(struct net *net, u32 addr);
 109
 110 int tipc_net_init(struct net *net, u8 *node_id, u32 addr)
 111 {
 112         if (tipc_own_id(net)) {
 113                 pr_info("Cannot configure node identity twice\n");
 114                 return -1;
 115         }
 116         pr_info("Started in network mode\n");
 117
 118         if (node_id)
 119                 tipc_set_node_id(net, node_id);
 120         if (addr)
 121                 tipc_net_finalize(net, addr);
 122         return 0;
 123 }
 124
 125 static void tipc_net_finalize(struct net *net, u32 addr)
 126 {
 127         struct tipc_net *tn = tipc_net(net);
 128
 129         if (cmpxchg(&tn->node_addr, 0, addr))
 130                 return;
 131         tipc_set_node_addr(net, addr);
 132         tipc_named_reinit(net);
 133         tipc_sk_reinit(net);
 134         tipc_mon_reinit_self(net);
 135         tipc_nametbl_publish(net, TIPC_NODE_STATE, addr, addr,
 136                              TIPC_CLUSTER_SCOPE, 0, addr);
 137 }
 138
 139 void tipc_net_finalize_work(struct work_struct *work)
 140 {
 141         struct tipc_net_work *fwork;
 142
 143         fwork = container_of(work, struct tipc_net_work, work);
 144         tipc_net_finalize(fwork->net, fwork->addr);
 145 }
 146
 147 void tipc_sched_net_finalize(struct net *net, u32 addr)
 148 {
 149         struct tipc_net *tn = tipc_net(net);
 150
 151         tn->final_work.net = net;
 152         tn->final_work.addr = addr;
 153         schedule_work(&tn->final_work.work);
 154 }
 155
 156 void tipc_net_stop(struct net *net)
 157 {
 158         if (!tipc_own_id(net))
 159                 return;
 160
 161         rtnl_lock();
 162         tipc_bearer_stop(net);
 163         tipc_node_stop(net);
 164         rtnl_unlock();
 165
 166         pr_info("Left network mode\n");
 167 }
 168
 169 static int __tipc_nl_add_net(struct net *net, struct tipc_nl_msg *msg)
 170 {
 171         struct tipc_net *tn = net_generic(net, tipc_net_id);
 172         u64 *w0 = (u64 *)&tn->node_id[0];
 173         u64 *w1 = (u64 *)&tn->node_id[8];
 174         struct nlattr *attrs;
 175         void *hdr;
 176
 177         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
 178                           NLM_F_MULTI, TIPC_NL_NET_GET);
 179         if (!hdr)
 180                 return -EMSGSIZE;
 181
 182         attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_NET);
 183         if (!attrs)
 184                 goto msg_full;
 185
 186         if (nla_put_u32(msg->skb, TIPC_NLA_NET_ID, tn->net_id))
 187                 goto attr_msg_full;
 188         if (nla_put_u64_64bit(msg->skb, TIPC_NLA_NET_NODEID, *w0, 0))
 189                 goto attr_msg_full;
 190         if (nla_put_u64_64bit(msg->skb, TIPC_NLA_NET_NODEID_W1, *w1, 0))
 191                 goto attr_msg_full;
 192         nla_nest_end(msg->skb, attrs);
 193         genlmsg_end(msg->skb, hdr);
 194
 195         return 0;
 196
 197 attr_msg_full:
 198         nla_nest_cancel(msg->skb, attrs);
 199 msg_full:
 200         genlmsg_cancel(msg->skb, hdr);
 201
 202         return -EMSGSIZE;
 203 }
 204
 205 int tipc_nl_net_dump(struct sk_buff *skb, struct netlink_callback *cb)
 206 {
 207         struct net *net = sock_net(skb->sk);
 208         int err;
 209         int done = cb->args[0];
 210         struct tipc_nl_msg msg;
 211
 212         if (done)
 213                 return 0;
 214
 215         msg.skb = skb;
 216         msg.portid = NETLINK_CB(cb->skb).portid;
 217         msg.seq = cb->nlh->nlmsg_seq;
 218
 219         err = __tipc_nl_add_net(net, &msg);
 220         if (err)
 221                 goto out;
 222
 223         done = 1;
 224 out:
 225         cb->args[0] = done;
 226
 227         return skb->len;
 228 }
 229
 230 int __tipc_nl_net_set(struct sk_buff *skb, struct genl_info *info)
 231 {
 232         struct nlattr *attrs[TIPC_NLA_NET_MAX + 1];
 233         struct net *net = sock_net(skb->sk);
 234         struct tipc_net *tn = tipc_net(net);
 235         int err;
 236
 237         if (!info->attrs[TIPC_NLA_NET])
 238                 return -EINVAL;
 239
 240         err = nla_parse_nested_deprecated(attrs, TIPC_NLA_NET_MAX,
 241                                           info->attrs[TIPC_NLA_NET],
 242                                           tipc_nl_net_policy, info->extack);
 243
 244         if (err)
 245                 return err;
 246
 247         /* Can't change net id once TIPC has joined a network */
 248         if (tipc_own_addr(net))
 249                 return -EPERM;
 250
 251         if (attrs[TIPC_NLA_NET_ID]) {
 252                 u32 val;
 253
 254                 val = nla_get_u32(attrs[TIPC_NLA_NET_ID]);
 255                 if (val < 1 || val > 9999)
 256                         return -EINVAL;
 257
 258                 tn->net_id = val;
 259         }
 260
 261         if (attrs[TIPC_NLA_NET_ADDR]) {
 262                 u32 addr;
 263
 264                 addr = nla_get_u32(attrs[TIPC_NLA_NET_ADDR]);
 265                 if (!addr)
 266                         return -EINVAL;
 267                 tn->legacy_addr_format = true;
 268                 tipc_net_init(net, NULL, addr);
 269         }
 270
 271         if (attrs[TIPC_NLA_NET_NODEID]) {
 272                 u8 node_id[NODE_ID_LEN];
 273                 u64 *w0 = (u64 *)&node_id[0];
 274                 u64 *w1 = (u64 *)&node_id[8];
 275
 276                 if (!attrs[TIPC_NLA_NET_NODEID_W1])
 277                         return -EINVAL;
 278                 *w0 = nla_get_u64(attrs[TIPC_NLA_NET_NODEID]);
 279                 *w1 = nla_get_u64(attrs[TIPC_NLA_NET_NODEID_W1]);
 280                 tipc_net_init(net, node_id, 0);
 281         }
 282         return 0;
 283 }
 284
 285 int tipc_nl_net_set(struct sk_buff *skb, struct genl_info *info)
 286 {
 287         int err;
 288
 289         rtnl_lock();
 290         err = __tipc_nl_net_set(skb, info);
 291         rtnl_unlock();
 292
 293         return err;
 294 }
 295
 296 static int __tipc_nl_addr_legacy_get(struct net *net, struct tipc_nl_msg *msg)
 297 {
 298         struct tipc_net *tn = tipc_net(net);
 299         struct nlattr *attrs;
 300         void *hdr;
 301
 302         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
 303                           0, TIPC_NL_ADDR_LEGACY_GET);
 304         if (!hdr)
 305                 return -EMSGSIZE;
 306
 307         attrs = nla_nest_start(msg->skb, TIPC_NLA_NET);
 308         if (!attrs)
 309                 goto msg_full;
 310
 311         if (tn->legacy_addr_format)
 312                 if (nla_put_flag(msg->skb, TIPC_NLA_NET_ADDR_LEGACY))
 313                         goto attr_msg_full;
 314
 315         nla_nest_end(msg->skb, attrs);
 316         genlmsg_end(msg->skb, hdr);
 317
 318         return 0;
 319
 320 attr_msg_full:
 321         nla_nest_cancel(msg->skb, attrs);
 322 msg_full:
 323         genlmsg_cancel(msg->skb, hdr);
 324
 325         return -EMSGSIZE;
 326 }
 327
 328 int tipc_nl_net_addr_legacy_get(struct sk_buff *skb, struct genl_info *info)
 329 {
 330         struct net *net = sock_net(skb->sk);
 331         struct tipc_nl_msg msg;
 332         struct sk_buff *rep;
 333         int err;
 334
 335         rep = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 336         if (!rep)
 337                 return -ENOMEM;
 338
 339         msg.skb = rep;
 340         msg.portid = info->snd_portid;
 341         msg.seq = info->snd_seq;
 342
 343         err = __tipc_nl_addr_legacy_get(net, &msg);
 344         if (err) {
 345                 nlmsg_free(msg.skb);
 346                 return err;
 347         }
 348
 349         return genlmsg_reply(msg.skb, info);
 350 }