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
  45 static const struct nla_policy tipc_nl_net_policy[TIPC_NLA_NET_MAX + 1] = {
  46         [TIPC_NLA_NET_UNSPEC]   = { .type = NLA_UNSPEC },
  47         [TIPC_NLA_NET_ID]       = { .type = NLA_U32 }
  48 };
  49
  50 /*
  51  * The TIPC locking policy is designed to ensure a very fine locking
  52  * granularity, permitting complete parallel access to individual
  53  * port and node/link instances. The code consists of four major
  54  * locking domains, each protected with their own disjunct set of locks.
  55  *
  56  * 1: The bearer level.
  57  *    RTNL lock is used to serialize the process of configuring bearer
  58  *    on update side, and RCU lock is applied on read side to make
  59  *    bearer instance valid on both paths of message transmission and
  60  *    reception.
  61  *
  62  * 2: The node and link level.
  63  *    All node instances are saved into two tipc_node_list and node_htable
  64  *    lists. The two lists are protected by node_list_lock on write side,
  65  *    and they are guarded with RCU lock on read side. Especially node
  66  *    instance is destroyed only when TIPC module is removed, and we can
  67  *    confirm that there has no any user who is accessing the node at the
  68  *    moment. Therefore, Except for iterating the two lists within RCU
  69  *    protection, it's no needed to hold RCU that we access node instance
  70  *    in other places.
  71  *
  72  *    In addition, all members in node structure including link instances
  73  *    are protected by node spin lock.
  74  *
  75  * 3: The transport level of the protocol.
  76  *    This consists of the structures port, (and its user level
  77  *    representations, such as user_port and tipc_sock), reference and
  78  *    tipc_user (port.c, reg.c, socket.c).
  79  *
  80  *    This layer has four different locks:
  81  *     - The tipc_port spin_lock. This is protecting each port instance
  82  *       from parallel data access and removal. Since we can not place
  83  *       this lock in the port itself, it has been placed in the
  84  *       corresponding reference table entry, which has the same life
  85  *       cycle as the module. This entry is difficult to access from
  86  *       outside the TIPC core, however, so a pointer to the lock has
  87  *       been added in the port instance, -to be used for unlocking
  88  *       only.
  89  *     - A read/write lock to protect the reference table itself (teg.c).
  90  *       (Nobody is using read-only access to this, so it can just as
  91  *       well be changed to a spin_lock)
  92  *     - A spin lock to protect the registry of kernel/driver users (reg.c)
  93  *     - A global spin_lock (tipc_port_lock), which only task is to ensure
  94  *       consistency where more than one port is involved in an operation,
  95  *       i.e., whe a port is part of a linked list of ports.
  96  *       There are two such lists; 'port_list', which is used for management,
  97  *       and 'wait_list', which is used to queue ports during congestion.
  98  *
  99  *  4: The name table (name_table.c, name_distr.c, subscription.c)
 100  *     - There is one big read/write-lock (tipc_nametbl_lock) protecting the
 101  *       overall name table structure. Nothing must be added/removed to
 102  *       this structure without holding write access to it.
 103  *     - There is one local spin_lock per sub_sequence, which can be seen
 104  *       as a sub-domain to the tipc_nametbl_lock domain. It is used only
 105  *       for translation operations, and is needed because a translation
 106  *       steps the root of the 'publication' linked list between each lookup.
 107  *       This is always used within the scope of a tipc_nametbl_lock(read).
 108  *     - A local spin_lock protecting the queue of subscriber events.
 109 */
 110
 111 int tipc_net_start(struct net *net, u32 addr)
 112 {
 113         struct tipc_net *tn = net_generic(net, tipc_net_id);
 114         char addr_string[16];
 115
 116         tn->own_addr = addr;
 117         tipc_named_reinit(net);
 118         tipc_sk_reinit(net);
 119         tipc_bcast_reinit(net);
 120
 121         tipc_nametbl_publish(net, TIPC_CFG_SRV, tn->own_addr, tn->own_addr,
 122                              TIPC_ZONE_SCOPE, 0, tn->own_addr);
 123
 124         pr_info("Started in network mode\n");
 125         pr_info("Own node address %s, network identity %u\n",
 126                 tipc_addr_string_fill(addr_string, tn->own_addr),
 127                 tn->net_id);
 128         return 0;
 129 }
 130
 131 void tipc_net_stop(struct net *net)
 132 {
 133         struct tipc_net *tn = net_generic(net, tipc_net_id);
 134
 135         if (!tn->own_addr)
 136                 return;
 137
 138         tipc_nametbl_withdraw(net, TIPC_CFG_SRV, tn->own_addr, 0,
 139                               tn->own_addr);
 140         rtnl_lock();
 141         tipc_bearer_stop(net);
 142         tipc_node_stop(net);
 143         rtnl_unlock();
 144
 145         pr_info("Left network mode\n");
 146 }
 147
 148 static int __tipc_nl_add_net(struct net *net, struct tipc_nl_msg *msg)
 149 {
 150         struct tipc_net *tn = net_generic(net, tipc_net_id);
 151         void *hdr;
 152         struct nlattr *attrs;
 153
 154         hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
 155                           NLM_F_MULTI, TIPC_NL_NET_GET);
 156         if (!hdr)
 157                 return -EMSGSIZE;
 158
 159         attrs = nla_nest_start(msg->skb, TIPC_NLA_NET);
 160         if (!attrs)
 161                 goto msg_full;
 162
 163         if (nla_put_u32(msg->skb, TIPC_NLA_NET_ID, tn->net_id))
 164                 goto attr_msg_full;
 165
 166         nla_nest_end(msg->skb, attrs);
 167         genlmsg_end(msg->skb, hdr);
 168
 169         return 0;
 170
 171 attr_msg_full:
 172         nla_nest_cancel(msg->skb, attrs);
 173 msg_full:
 174         genlmsg_cancel(msg->skb, hdr);
 175
 176         return -EMSGSIZE;
 177 }
 178
 179 int tipc_nl_net_dump(struct sk_buff *skb, struct netlink_callback *cb)
 180 {
 181         struct net *net = sock_net(skb->sk);
 182         int err;
 183         int done = cb->args[0];
 184         struct tipc_nl_msg msg;
 185
 186         if (done)
 187                 return 0;
 188
 189         msg.skb = skb;
 190         msg.portid = NETLINK_CB(cb->skb).portid;
 191         msg.seq = cb->nlh->nlmsg_seq;
 192
 193         err = __tipc_nl_add_net(net, &msg);
 194         if (err)
 195                 goto out;
 196
 197         done = 1;
 198 out:
 199         cb->args[0] = done;
 200
 201         return skb->len;
 202 }
 203
 204 int tipc_nl_net_set(struct sk_buff *skb, struct genl_info *info)
 205 {
 206         struct net *net = sock_net(skb->sk);
 207         struct tipc_net *tn = net_generic(net, tipc_net_id);
 208         struct nlattr *attrs[TIPC_NLA_NET_MAX + 1];
 209         int err;
 210
 211         if (!info->attrs[TIPC_NLA_NET])
 212                 return -EINVAL;
 213
 214         err = nla_parse_nested(attrs, TIPC_NLA_NET_MAX,
 215                                info->attrs[TIPC_NLA_NET],
 216                                tipc_nl_net_policy);
 217         if (err)
 218                 return err;
 219
 220         if (attrs[TIPC_NLA_NET_ID]) {
 221                 u32 val;
 222
 223                 /* Can't change net id once TIPC has joined a network */
 224                 if (tn->own_addr)
 225                         return -EPERM;
 226
 227                 val = nla_get_u32(attrs[TIPC_NLA_NET_ID]);
 228                 if (val < 1 || val > 9999)
 229                         return -EINVAL;
 230
 231                 tn->net_id = val;
 232         }
 233
 234         if (attrs[TIPC_NLA_NET_ADDR]) {
 235                 u32 addr;
 236
 237                 /* Can't change net addr once TIPC has joined a network */
 238                 if (tn->own_addr)
 239                         return -EPERM;
 240
 241                 addr = nla_get_u32(attrs[TIPC_NLA_NET_ADDR]);
 242                 if (!tipc_addr_node_valid(addr))
 243                         return -EINVAL;
 244
 245                 rtnl_lock();
 246                 tipc_net_start(net, addr);
 247                 rtnl_unlock();
 248         }
 249
 250         return 0;
 251 }