LXR linux/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
  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
 107struct tipc_net_work {
 108        struct work_struct work;
 109        struct net *net;
 110        u32 addr;
 111};
 112
 113static void tipc_net_finalize(struct net *net, u32 addr);
 114
 115int tipc_net_init(struct net *net, u8 *node_id, u32 addr)
 116{
 117        if (tipc_own_id(net)) {
 118                pr_info("Cannot configure node identity twice\n");
 119                return -1;
 120        }
 121        pr_info("Started in network mode\n");
 122
 123        if (node_id)
 124                tipc_set_node_id(net, node_id);
 125        if (addr)
 126                tipc_net_finalize(net, addr);
 127        return 0;
 128}
 129
 130static void tipc_net_finalize(struct net *net, u32 addr)
 131{
 132        struct tipc_net *tn = tipc_net(net);
 133
 134        if (cmpxchg(&tn->node_addr, 0, addr))
 135                return;
 136        tipc_set_node_addr(net, addr);
 137        tipc_named_reinit(net);
 138        tipc_sk_reinit(net);
 139        tipc_nametbl_publish(net, TIPC_CFG_SRV, addr, addr,
 140                             TIPC_CLUSTER_SCOPE, 0, addr);
 141}
 142
 143static void tipc_net_finalize_work(struct work_struct *work)
 144{
 145        struct tipc_net_work *fwork;
 146
 147        fwork = container_of(work, struct tipc_net_work, work);
 148        tipc_net_finalize(fwork->net, fwork->addr);
 149        kfree(fwork);
 150}
 151
 152void tipc_sched_net_finalize(struct net *net, u32 addr)
 153{
 154        struct tipc_net_work *fwork = kzalloc(sizeof(*fwork), GFP_ATOMIC);
 155
 156        if (!fwork)
 157                return;
 158        INIT_WORK(&fwork->work, tipc_net_finalize_work);
 159        fwork->net = net;
 160        fwork->addr = addr;
 161        schedule_work(&fwork->work);
 162}
 163
 164void tipc_net_stop(struct net *net)
 165{
 166        if (!tipc_own_id(net))
 167                return;
 168
 169        rtnl_lock();
 170        tipc_bearer_stop(net);
 171        tipc_node_stop(net);
 172        rtnl_unlock();
 173
 174        pr_info("Left network mode\n");
 175}
 176
 177static int __tipc_nl_add_net(struct net *net, struct tipc_nl_msg *msg)
 178{
 179        struct tipc_net *tn = net_generic(net, tipc_net_id);
 180        u64 *w0 = (u64 *)&tn->node_id[0];
 181        u64 *w1 = (u64 *)&tn->node_id[8];
 182        struct nlattr *attrs;
 183        void *hdr;
 184
 185        hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
 186                          NLM_F_MULTI, TIPC_NL_NET_GET);
 187        if (!hdr)
 188                return -EMSGSIZE;
 189
 190        attrs = nla_nest_start_noflag(msg->skb, TIPC_NLA_NET);
 191        if (!attrs)
 192                goto msg_full;
 193
 194        if (nla_put_u32(msg->skb, TIPC_NLA_NET_ID, tn->net_id))
 195                goto attr_msg_full;
 196        if (nla_put_u64_64bit(msg->skb, TIPC_NLA_NET_NODEID, *w0, 0))
 197                goto attr_msg_full;
 198        if (nla_put_u64_64bit(msg->skb, TIPC_NLA_NET_NODEID_W1, *w1, 0))
 199                goto attr_msg_full;
 200        nla_nest_end(msg->skb, attrs);
 201        genlmsg_end(msg->skb, hdr);
 202
 203        return 0;
 204
 205attr_msg_full:
 206        nla_nest_cancel(msg->skb, attrs);
 207msg_full:
 208        genlmsg_cancel(msg->skb, hdr);
 209
 210        return -EMSGSIZE;
 211}
 212
 213int tipc_nl_net_dump(struct sk_buff *skb, struct netlink_callback *cb)
 214{
 215        struct net *net = sock_net(skb->sk);
 216        int err;
 217        int done = cb->args[0];
 218        struct tipc_nl_msg msg;
 219
 220        if (done)
 221                return 0;
 222
 223        msg.skb = skb;
 224        msg.portid = NETLINK_CB(cb->skb).portid;
 225        msg.seq = cb->nlh->nlmsg_seq;
 226
 227        err = __tipc_nl_add_net(net, &msg);
 228        if (err)
 229                goto out;
 230
 231        done = 1;
 232out:
 233        cb->args[0] = done;
 234
 235        return skb->len;
 236}
 237
 238int __tipc_nl_net_set(struct sk_buff *skb, struct genl_info *info)
 239{
 240        struct nlattr *attrs[TIPC_NLA_NET_MAX + 1];
 241        struct net *net = sock_net(skb->sk);
 242        struct tipc_net *tn = tipc_net(net);
 243        int err;
 244
 245        if (!info->attrs[TIPC_NLA_NET])
 246                return -EINVAL;
 247
 248        err = nla_parse_nested_deprecated(attrs, TIPC_NLA_NET_MAX,
 249                                          info->attrs[TIPC_NLA_NET],
 250                                          tipc_nl_net_policy, info->extack);
 251
 252        if (err)
 253                return err;
 254
 255        /* Can't change net id once TIPC has joined a network */
 256        if (tipc_own_addr(net))
 257                return -EPERM;
 258
 259        if (attrs[TIPC_NLA_NET_ID]) {
 260                u32 val;
 261
 262                val = nla_get_u32(attrs[TIPC_NLA_NET_ID]);
 263                if (val < 1 || val > 9999)
 264                        return -EINVAL;
 265
 266                tn->net_id = val;
 267        }
 268
 269        if (attrs[TIPC_NLA_NET_ADDR]) {
 270                u32 addr;
 271
 272                addr = nla_get_u32(attrs[TIPC_NLA_NET_ADDR]);
 273                if (!addr)
 274                        return -EINVAL;
 275                tn->legacy_addr_format = true;
 276                tipc_net_init(net, NULL, addr);
 277        }
 278
 279        if (attrs[TIPC_NLA_NET_NODEID]) {
 280                u8 node_id[NODE_ID_LEN];
 281                u64 *w0 = (u64 *)&node_id[0];
 282                u64 *w1 = (u64 *)&node_id[8];
 283
 284                if (!attrs[TIPC_NLA_NET_NODEID_W1])
 285                        return -EINVAL;
 286                *w0 = nla_get_u64(attrs[TIPC_NLA_NET_NODEID]);
 287                *w1 = nla_get_u64(attrs[TIPC_NLA_NET_NODEID_W1]);
 288                tipc_net_init(net, node_id, 0);
 289        }
 290        return 0;
 291}
 292
 293int tipc_nl_net_set(struct sk_buff *skb, struct genl_info *info)
 294{
 295        int err;
 296
 297        rtnl_lock();
 298        err = __tipc_nl_net_set(skb, info);
 299        rtnl_unlock();
 300
 301        return err;
 302}
 303