net/tipc/net.c

   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
 118 DEFINE_RWLOCK(tipc_net_lock);
 119 static struct _zone *tipc_zones[256] = { NULL, };
 120 struct network tipc_net = { tipc_zones };
 121
 122 struct 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
 127 u32 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
 133 u32 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
 141 void 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
 152 void 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
 162 static 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
 170 static 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
 196 void 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
 254 int 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
 284 void 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