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