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
 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 }