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, 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 "bearer.h"
  39#include "net.h"
  40#include "zone.h"
  41#include "addr.h"
  42#include "name_table.h"
  43#include "name_distr.h"
  44#include "subscr.h"
  45#include "link.h"
  46#include "msg.h"
  47#include "port.h"
  48#include "bcast.h"
  49#include "discover.h"
  50#include "config.h"
  51
  52/*
  53 * The TIPC locking policy is designed to ensure a very fine locking
  54 * granularity, permitting complete parallel access to individual
  55 * port and node/link instances. The code consists of three major
  56 * locking domains, each protected with their own disjunct set of locks.
  57 *
  58 * 1: The routing hierarchy.
  59 *    Comprises the structures 'zone', 'cluster', 'node', 'link'
  60 *    and 'bearer'. The whole hierarchy is protected by a big
  61 *    read/write lock, tipc_net_lock, to enssure that nothing is added
  62 *    or removed while code is accessing any of these structures.
  63 *    This layer must not be called from the two others while they
  64 *    hold any of their own locks.
  65 *    Neither must it itself do any upcalls to the other two before
  66 *    it has released tipc_net_lock and other protective locks.
  67 *
  68 *   Within the tipc_net_lock domain there are two sub-domains;'node' and
  69 *   'bearer', where local write operations are permitted,
  70 *   provided that those are protected by individual spin_locks
  71 *   per instance. Code holding tipc_net_lock(read) and a node spin_lock
  72 *   is permitted to poke around in both the node itself and its
  73 *   subordinate links. I.e, it can update link counters and queues,
  74 *   change link state, send protocol messages, and alter the
  75 *   "active_links" array in the node; but it can _not_ remove a link
  76 *   or a node from the overall structure.
  77 *   Correspondingly, individual bearers may change status within a
  78 *   tipc_net_lock(read), protected by an individual spin_lock ber bearer
  79 *   instance, but it needs tipc_net_lock(write) to remove/add any bearers.
  80 *
  81 *
  82 *  2: The transport level of the protocol.
  83 *     This consists of the structures port, (and its user level
  84 *     representations, such as user_port and tipc_sock), reference and
  85 *     tipc_user (port.c, reg.c, socket.c).
  86 *
  87 *     This layer has four different locks:
  88 *     - The tipc_port spin_lock. This is protecting each port instance
  89 *       from parallel data access and removal. Since we can not place
  90 *       this lock in the port itself, it has been placed in the
  91 *       corresponding reference table entry, which has the same life
  92 *       cycle as the module. This entry is difficult to access from
  93 *       outside the TIPC core, however, so a pointer to the lock has
  94 *       been added in the port instance, -to be used for unlocking
  95 *       only.
  96 *     - A read/write lock to protect the reference table itself (teg.c).
  97 *       (Nobody is using read-only access to this, so it can just as
  98 *       well be changed to a spin_lock)
  99 *     - A spin lock to protect the registry of kernel/driver users (reg.c)
 100 *     - A global spin_lock (tipc_port_lock), which only task is to ensure
 101 *       consistency where more than one port is involved in an operation,
 102 *       i.e., whe a port is part of a linked list of ports.
 103 *       There are two such lists; 'port_list', which is used for management,
 104 *       and 'wait_list', which is used to queue ports during congestion.
 105 *
 106 *  3: The name table (name_table.c, name_distr.c, subscription.c)
 107 *     - There is one big read/write-lock (tipc_nametbl_lock) protecting the
 108 *       overall name table structure. Nothing must be added/removed to
 109 *       this structure without holding write access to it.
 110 *     - There is one local spin_lock per sub_sequence, which can be seen
 111 *       as a sub-domain to the tipc_nametbl_lock domain. It is used only
 112 *       for translation operations, and is needed because a translation
 113 *       steps the root of the 'publication' linked list between each lookup.
 114 *       This is always used within the scope of a tipc_nametbl_lock(read).
 115 *     - A local spin_lock protecting the queue of subscriber events.
 116*/
 117
 118DEFINE_RWLOCK(tipc_net_lock);
 119static struct _zone *tipc_zones[256] = { NULL, };
 120struct network tipc_net = { tipc_zones };
 121
 122struct tipc_node *tipc_net_select_remote_node(u32 addr, u32 ref)
 123{
 124        return tipc_zone_select_remote_node(tipc_net.zones[tipc_zone(addr)], addr, ref);
 125}
 126
 127u32 tipc_net_select_router(u32 addr, u32 ref)
 128{
 129        return tipc_zone_select_router(tipc_net.zones[tipc_zone(addr)], addr, ref);
 130}
 131
 132#if 0
 133u32 tipc_net_next_node(u32 a)
 134{
 135        if (tipc_net.zones[tipc_zone(a)])
 136                return tipc_zone_next_node(a);
 137        return 0;
 138}
 139#endif
 140
 141void tipc_net_remove_as_router(u32 router)
 142{
 143        u32 z_num;
 144
 145        for (z_num = 1; z_num <= tipc_max_zones; z_num++) {
 146                if (!tipc_net.zones[z_num])
 147                        continue;
 148                tipc_zone_remove_as_router(tipc_net.zones[z_num], router);
 149        }
 150}
 151
 152void tipc_net_send_external_routes(u32 dest)
 153{
 154        u32 z_num;
 155
 156        for (z_num = 1; z_num <= tipc_max_zones; z_num++) {
 157                if (tipc_net.zones[z_num])
 158                        tipc_zone_send_external_routes(tipc_net.zones[z_num], dest);
 159        }
 160}
 161
 162static void net_stop(void)
 163{
 164        u32 z_num;
 165
 166        for (z_num = 1; z_num <= tipc_max_zones; z_num++)
 167                tipc_zone_delete(tipc_net.zones[z_num]);
 168}
 169
 170static void net_route_named_msg(struct sk_buff *buf)
 171{
 172        struct tipc_msg *msg = buf_msg(buf);
 173        u32 dnode;
 174        u32 dport;
 175
 176        if (!msg_named(msg)) {
 177                msg_dbg(msg, "tipc_net->drop_nam:");
 178                buf_discard(buf);
 179                return;
 180        }
 181
 182        dnode = addr_domain(msg_lookup_scope(msg));
 183        dport = tipc_nametbl_translate(msg_nametype(msg), msg_nameinst(msg), &dnode);
 184        dbg("tipc_net->lookup<%u,%u>-><%u,%x>\n",
 185            msg_nametype(msg), msg_nameinst(msg), dport, dnode);
 186        if (dport) {
 187                msg_set_destnode(msg, dnode);
 188                msg_set_destport(msg, dport);
 189                tipc_net_route_msg(buf);
 190                return;
 191        }
 192        msg_dbg(msg, "tipc_net->rej:NO NAME: ");
 193        tipc_reject_msg(buf, TIPC_ERR_NO_NAME);
 194}
 195
 196void tipc_net_route_msg(struct sk_buff *buf)
 197{
 198        struct tipc_msg *msg;
 199        u32 dnode;
 200
 201        if (!buf)
 202                return;
 203        msg = buf_msg(buf);
 204
 205        msg_incr_reroute_cnt(msg);
 206        if (msg_reroute_cnt(msg) > 6) {
 207                if (msg_errcode(msg)) {
 208                        msg_dbg(msg, "NET>DISC>:");
 209                        buf_discard(buf);
 210                } else {
 211                        msg_dbg(msg, "NET>REJ>:");
 212                        tipc_reject_msg(buf, msg_destport(msg) ?
 213                                        TIPC_ERR_NO_PORT : TIPC_ERR_NO_NAME);
 214                }
 215                return;
 216        }
 217
 218        msg_dbg(msg, "tipc_net->rout: ");
 219
 220        /* Handle message for this node */
 221        dnode = msg_short(msg) ? tipc_own_addr : msg_destnode(msg);
 222        if (tipc_in_scope(dnode, tipc_own_addr)) {
 223                if (msg_isdata(msg)) {
 224                        if (msg_mcast(msg))
 225                                tipc_port_recv_mcast(buf, NULL);
 226                        else if (msg_destport(msg))
 227                                tipc_port_recv_msg(buf);
 228                        else
 229                                net_route_named_msg(buf);
 230                        return;
 231                }
 232                switch (msg_user(msg)) {
 233                case ROUTE_DISTRIBUTOR:
 234                        tipc_cltr_recv_routing_table(buf);
 235                        break;
 236                case NAME_DISTRIBUTOR:
 237                        tipc_named_recv(buf);
 238                        break;
 239                case CONN_MANAGER:
 240                        tipc_port_recv_proto_msg(buf);
 241                        break;
 242                default:
 243                        msg_dbg(msg,"DROP/NET/<REC<");
 244                        buf_discard(buf);
 245                }
 246                return;
 247        }
 248
 249        /* Handle message for another node */
 250        msg_dbg(msg, "NET>SEND>: ");
 251        tipc_link_send(buf, dnode, msg_link_selector(msg));
 252}
 253
 254int tipc_net_start(u32 addr)
 255{
 256        char addr_string[16];
 257        int res;
 258
 259        if (tipc_mode != TIPC_NODE_MODE)
 260                return -ENOPROTOOPT;
 261
 262        tipc_subscr_stop();
 263        tipc_cfg_stop();
 264
 265        tipc_own_addr = addr;
 266        tipc_mode = TIPC_NET_MODE;
 267        tipc_named_reinit();
 268        tipc_port_reinit();
 269
 270        if ((res = tipc_cltr_init()) ||
 271            (res = tipc_bclink_init())) {
 272                return res;
 273        }
 274
 275        tipc_k_signal((Handler)tipc_subscr_start, 0);
 276        tipc_k_signal((Handler)tipc_cfg_init, 0);
 277
 278        info("Started in network mode\n");
 279        info("Own node address %s, network identity %u\n",
 280             tipc_addr_string_fill(addr_string, tipc_own_addr), tipc_net_id);
 281        return 0;
 282}
 283
 284void tipc_net_stop(void)
 285{
 286        if (tipc_mode != TIPC_NET_MODE)
 287                return;
 288        write_lock_bh(&tipc_net_lock);
 289        tipc_bearer_stop();
 290        tipc_mode = TIPC_NODE_MODE;
 291        tipc_bclink_stop();
 292        net_stop();
 293        write_unlock_bh(&tipc_net_lock);
 294        info("Left network mode\n");
 295}
 296
 297