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, 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 "port.h"
  42#include "node.h"
  43#include "config.h"
  44
  45/*
  46 * The TIPC locking policy is designed to ensure a very fine locking
  47 * granularity, permitting complete parallel access to individual
  48 * port and node/link instances. The code consists of three major
  49 * locking domains, each protected with their own disjunct set of locks.
  50 *
  51 * 1: The routing hierarchy.
  52 *    Comprises the structures 'zone', 'cluster', 'node', 'link'
  53 *    and 'bearer'. The whole hierarchy is protected by a big
  54 *    read/write lock, tipc_net_lock, to enssure that nothing is added
  55 *    or removed while code is accessing any of these structures.
  56 *    This layer must not be called from the two others while they
  57 *    hold any of their own locks.
  58 *    Neither must it itself do any upcalls to the other two before
  59 *    it has released tipc_net_lock and other protective locks.
  60 *
  61 *   Within the tipc_net_lock domain there are two sub-domains;'node' and
  62 *   'bearer', where local write operations are permitted,
  63 *   provided that those are protected by individual spin_locks
  64 *   per instance. Code holding tipc_net_lock(read) and a node spin_lock
  65 *   is permitted to poke around in both the node itself and its
  66 *   subordinate links. I.e, it can update link counters and queues,
  67 *   change link state, send protocol messages, and alter the
  68 *   "active_links" array in the node; but it can _not_ remove a link
  69 *   or a node from the overall structure.
  70 *   Correspondingly, individual bearers may change status within a
  71 *   tipc_net_lock(read), protected by an individual spin_lock ber bearer
  72 *   instance, but it needs tipc_net_lock(write) to remove/add any bearers.
  73 *
  74 *
  75 *  2: 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 *  3: 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
 111DEFINE_RWLOCK(tipc_net_lock);
 112
 113static void net_route_named_msg(struct sk_buff *buf)
 114{
 115        struct tipc_msg *msg = buf_msg(buf);
 116        u32 dnode;
 117        u32 dport;
 118
 119        if (!msg_named(msg)) {
 120                kfree_skb(buf);
 121                return;
 122        }
 123
 124        dnode = addr_domain(msg_lookup_scope(msg));
 125        dport = tipc_nametbl_translate(msg_nametype(msg), msg_nameinst(msg), &dnode);
 126        if (dport) {
 127                msg_set_destnode(msg, dnode);
 128                msg_set_destport(msg, dport);
 129                tipc_net_route_msg(buf);
 130                return;
 131        }
 132        tipc_reject_msg(buf, TIPC_ERR_NO_NAME);
 133}
 134
 135void tipc_net_route_msg(struct sk_buff *buf)
 136{
 137        struct tipc_msg *msg;
 138        u32 dnode;
 139
 140        if (!buf)
 141                return;
 142        msg = buf_msg(buf);
 143
 144        /* Handle message for this node */
 145        dnode = msg_short(msg) ? tipc_own_addr : msg_destnode(msg);
 146        if (tipc_in_scope(dnode, tipc_own_addr)) {
 147                if (msg_isdata(msg)) {
 148                        if (msg_mcast(msg))
 149                                tipc_port_recv_mcast(buf, NULL);
 150                        else if (msg_destport(msg))
 151                                tipc_port_recv_msg(buf);
 152                        else
 153                                net_route_named_msg(buf);
 154                        return;
 155                }
 156                switch (msg_user(msg)) {
 157                case NAME_DISTRIBUTOR:
 158                        tipc_named_recv(buf);
 159                        break;
 160                case CONN_MANAGER:
 161                        tipc_port_recv_proto_msg(buf);
 162                        break;
 163                default:
 164                        kfree_skb(buf);
 165                }
 166                return;
 167        }
 168
 169        /* Handle message for another node */
 170        skb_trim(buf, msg_size(msg));
 171        tipc_link_send(buf, dnode, msg_link_selector(msg));
 172}
 173
 174void tipc_net_start(u32 addr)
 175{
 176        char addr_string[16];
 177
 178        write_lock_bh(&tipc_net_lock);
 179        tipc_own_addr = addr;
 180        tipc_named_reinit();
 181        tipc_port_reinit();
 182        tipc_bclink_init();
 183        write_unlock_bh(&tipc_net_lock);
 184
 185        tipc_cfg_reinit();
 186
 187        pr_info("Started in network mode\n");
 188        pr_info("Own node address %s, network identity %u\n",
 189                tipc_addr_string_fill(addr_string, tipc_own_addr), tipc_net_id);
 190}
 191
 192void tipc_net_stop(void)
 193{
 194        struct tipc_node *node, *t_node;
 195
 196        if (!tipc_own_addr)
 197                return;
 198        write_lock_bh(&tipc_net_lock);
 199        tipc_bearer_stop();
 200        tipc_bclink_stop();
 201        list_for_each_entry_safe(node, t_node, &tipc_node_list, list)
 202                tipc_node_delete(node);
 203        write_unlock_bh(&tipc_net_lock);
 204        pr_info("Left network mode\n");
 205}
 206
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