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 "net.h"
  39 #include "name_distr.h"
  40 #include "subscr.h"
  41 #include "port.h"
  42 #include "config.h"
  43
  44 /*
  45  * The TIPC locking policy is designed to ensure a very fine locking
  46  * granularity, permitting complete parallel access to individual
  47  * port and node/link instances. The code consists of three major
  48  * locking domains, each protected with their own disjunct set of locks.
  49  *
  50  * 1: The routing hierarchy.
  51  *    Comprises the structures 'zone', 'cluster', 'node', 'link'
  52  *    and 'bearer'. The whole hierarchy is protected by a big
  53  *    read/write lock, tipc_net_lock, to enssure that nothing is added
  54  *    or removed while code is accessing any of these structures.
  55  *    This layer must not be called from the two others while they
  56  *    hold any of their own locks.
  57  *    Neither must it itself do any upcalls to the other two before
  58  *    it has released tipc_net_lock and other protective locks.
  59  *
  60  *   Within the tipc_net_lock domain there are two sub-domains;'node' and
  61  *   'bearer', where local write operations are permitted,
  62  *   provided that those are protected by individual spin_locks
  63  *   per instance. Code holding tipc_net_lock(read) and a node spin_lock
  64  *   is permitted to poke around in both the node itself and its
  65  *   subordinate links. I.e, it can update link counters and queues,
  66  *   change link state, send protocol messages, and alter the
  67  *   "active_links" array in the node; but it can _not_ remove a link
  68  *   or a node from the overall structure.
  69  *   Correspondingly, individual bearers may change status within a
  70  *   tipc_net_lock(read), protected by an individual spin_lock ber bearer
  71  *   instance, but it needs tipc_net_lock(write) to remove/add any bearers.
  72  *
  73  *
  74  *  2: The transport level of the protocol.
  75  *     This consists of the structures port, (and its user level
  76  *     representations, such as user_port and tipc_sock), reference and
  77  *     tipc_user (port.c, reg.c, socket.c).
  78  *
  79  *     This layer has four different locks:
  80  *     - The tipc_port spin_lock. This is protecting each port instance
  81  *       from parallel data access and removal. Since we can not place
  82  *       this lock in the port itself, it has been placed in the
  83  *       corresponding reference table entry, which has the same life
  84  *       cycle as the module. This entry is difficult to access from
  85  *       outside the TIPC core, however, so a pointer to the lock has
  86  *       been added in the port instance, -to be used for unlocking
  87  *       only.
  88  *     - A read/write lock to protect the reference table itself (teg.c).
  89  *       (Nobody is using read-only access to this, so it can just as
  90  *       well be changed to a spin_lock)
  91  *     - A spin lock to protect the registry of kernel/driver users (reg.c)
  92  *     - A global spin_lock (tipc_port_lock), which only task is to ensure
  93  *       consistency where more than one port is involved in an operation,
  94  *       i.e., whe a port is part of a linked list of ports.
  95  *       There are two such lists; 'port_list', which is used for management,
  96  *       and 'wait_list', which is used to queue ports during congestion.
  97  *
  98  *  3: The name table (name_table.c, name_distr.c, subscription.c)
  99  *     - There is one big read/write-lock (tipc_nametbl_lock) protecting the
 100  *       overall name table structure. Nothing must be added/removed to
 101  *       this structure without holding write access to it.
 102  *     - There is one local spin_lock per sub_sequence, which can be seen
 103  *       as a sub-domain to the tipc_nametbl_lock domain. It is used only
 104  *       for translation operations, and is needed because a translation
 105  *       steps the root of the 'publication' linked list between each lookup.
 106  *       This is always used within the scope of a tipc_nametbl_lock(read).
 107  *     - A local spin_lock protecting the queue of subscriber events.
 108 */
 109
 110 DEFINE_RWLOCK(tipc_net_lock);
 111 struct network tipc_net;
 112
 113 static int net_start(void)
 114 {
 115         tipc_net.nodes = kcalloc(tipc_max_nodes + 1,
 116                                  sizeof(*tipc_net.nodes), GFP_ATOMIC);
 117         tipc_net.highest_node = 0;
 118
 119         return tipc_net.nodes ? 0 : -ENOMEM;
 120 }
 121
 122 static void net_stop(void)
 123 {
 124         u32 n_num;
 125
 126         for (n_num = 1; n_num <= tipc_net.highest_node; n_num++)
 127                 tipc_node_delete(tipc_net.nodes[n_num]);
 128         kfree(tipc_net.nodes);
 129         tipc_net.nodes = NULL;
 130 }
 131
 132 static void net_route_named_msg(struct sk_buff *buf)
 133 {
 134         struct tipc_msg *msg = buf_msg(buf);
 135         u32 dnode;
 136         u32 dport;
 137
 138         if (!msg_named(msg)) {
 139                 buf_discard(buf);
 140                 return;
 141         }
 142
 143         dnode = addr_domain(msg_lookup_scope(msg));
 144         dport = tipc_nametbl_translate(msg_nametype(msg), msg_nameinst(msg), &dnode);
 145         if (dport) {
 146                 msg_set_destnode(msg, dnode);
 147                 msg_set_destport(msg, dport);
 148                 tipc_net_route_msg(buf);
 149                 return;
 150         }
 151         tipc_reject_msg(buf, TIPC_ERR_NO_NAME);
 152 }
 153
 154 void tipc_net_route_msg(struct sk_buff *buf)
 155 {
 156         struct tipc_msg *msg;
 157         u32 dnode;
 158
 159         if (!buf)
 160                 return;
 161         msg = buf_msg(buf);
 162
 163         msg_incr_reroute_cnt(msg);
 164         if (msg_reroute_cnt(msg) > 6) {
 165                 if (msg_errcode(msg)) {
 166                         buf_discard(buf);
 167                 } else {
 168                         tipc_reject_msg(buf, msg_destport(msg) ?
 169                                         TIPC_ERR_NO_PORT : TIPC_ERR_NO_NAME);
 170                 }
 171                 return;
 172         }
 173
 174         /* Handle message for this node */
 175         dnode = msg_short(msg) ? tipc_own_addr : msg_destnode(msg);
 176         if (tipc_in_scope(dnode, tipc_own_addr)) {
 177                 if (msg_isdata(msg)) {
 178                         if (msg_mcast(msg))
 179                                 tipc_port_recv_mcast(buf, NULL);
 180                         else if (msg_destport(msg))
 181                                 tipc_port_recv_msg(buf);
 182                         else
 183                                 net_route_named_msg(buf);
 184                         return;
 185                 }
 186                 switch (msg_user(msg)) {
 187                 case NAME_DISTRIBUTOR:
 188                         tipc_named_recv(buf);
 189                         break;
 190                 case CONN_MANAGER:
 191                         tipc_port_recv_proto_msg(buf);
 192                         break;
 193                 default:
 194                         buf_discard(buf);
 195                 }
 196                 return;
 197         }
 198
 199         /* Handle message for another node */
 200         skb_trim(buf, msg_size(msg));
 201         tipc_link_send(buf, dnode, msg_link_selector(msg));
 202 }
 203
 204 int tipc_net_start(u32 addr)
 205 {
 206         char addr_string[16];
 207         int res;
 208
 209         if (tipc_mode != TIPC_NODE_MODE)
 210                 return -ENOPROTOOPT;
 211
 212         tipc_subscr_stop();
 213         tipc_cfg_stop();
 214
 215         tipc_own_addr = addr;
 216         tipc_mode = TIPC_NET_MODE;
 217         tipc_named_reinit();
 218         tipc_port_reinit();
 219
 220         res = net_start();
 221         if (res)
 222                 return res;
 223         res = tipc_bclink_init();
 224         if (res)
 225                 return res;
 226
 227         tipc_k_signal((Handler)tipc_subscr_start, 0);
 228         tipc_k_signal((Handler)tipc_cfg_init, 0);
 229
 230         info("Started in network mode\n");
 231         info("Own node address %s, network identity %u\n",
 232              tipc_addr_string_fill(addr_string, tipc_own_addr), tipc_net_id);
 233         return 0;
 234 }
 235
 236 void tipc_net_stop(void)
 237 {
 238         if (tipc_mode != TIPC_NET_MODE)
 239                 return;
 240         write_lock_bh(&tipc_net_lock);
 241         tipc_bearer_stop();
 242         tipc_mode = TIPC_NODE_MODE;
 243         tipc_bclink_stop();
 244         net_stop();
 245         write_unlock_bh(&tipc_net_lock);
 246         info("Left network mode\n");
 247 }
 248