src/net.c

   1 /*
   2     net.c -- most of the network code
   3     Copyright (C) 1998-2005 Ivo Timmermans,
   4                   2000-2010 Guus Sliepen <guus@tinc-vpn.org>
   5                   2006      Scott Lamb <slamb@slamb.org>
   6
   7     This program is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License along
  18     with this program; if not, write to the Free Software Foundation, Inc.,
  19     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20 */
  21
  22 #include "system.h"
  23
  24 #include "utils.h"
  25 #include "splay_tree.h"
  26 #include "conf.h"
  27 #include "connection.h"
  28 #include "device.h"
  29 #include "graph.h"
  30 #include "logger.h"
  31 #include "meta.h"
  32 #include "net.h"
  33 #include "netutl.h"
  34 #include "process.h"
  35 #include "protocol.h"
  36 #include "subnet.h"
  37 #include "xalloc.h"
  38
  39 int contradicting_add_edge = 0;
  40 int contradicting_del_edge = 0;
  41 bool running = true;
  42
  43 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  44
  45 void purge(void) {
  46         splay_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
  47         node_t *n;
  48         edge_t *e;
  49         subnet_t *s;
  50
  51         ifdebug(PROTOCOL) logger(LOG_DEBUG, "Purging unreachable nodes");
  52
  53         /* Remove all edges and subnets owned by unreachable nodes. */
  54
  55         for(nnode = node_tree->head; nnode; nnode = nnext) {
  56                 nnext = nnode->next;
  57                 n = nnode->data;
  58
  59                 if(!n->status.reachable) {
  60                         ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Purging node %s (%s)", n->name,
  61                                            n->hostname);
  62
  63                         for(snode = n->subnet_tree->head; snode; snode = snext) {
  64                                 snext = snode->next;
  65                                 s = snode->data;
  66                                 send_del_subnet(broadcast, s);
  67                                 if(!strictsubnets)
  68                                         subnet_del(n, s);
  69                         }
  70
  71                         for(enode = n->edge_tree->head; enode; enode = enext) {
  72                                 enext = enode->next;
  73                                 e = enode->data;
  74                                 if(!tunnelserver)
  75                                         send_del_edge(broadcast, e);
  76                                 edge_del(e);
  77                         }
  78                 }
  79         }
  80
  81         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  82
  83         for(nnode = node_tree->head; nnode; nnode = nnext) {
  84                 nnext = nnode->next;
  85                 n = nnode->data;
  86
  87                 if(!n->status.reachable) {
  88                         for(enode = edge_weight_tree->head; enode; enode = enext) {
  89                                 enext = enode->next;
  90                                 e = enode->data;
  91
  92                                 if(e->to == n)
  93                                         break;
  94                         }
  95
  96                         if(!enode && (!strictsubnets || !n->subnet_tree->head))
  97                                 /* in strictsubnets mode do not delete nodes with subnets */
  98                                 node_del(n);
  99                 }
 100         }
 101 }
 102
 103 /*
 104   Terminate a connection:
 105   - Close the socket
 106   - Remove associated edge and tell other connections about it if report = true
 107   - Check if we need to retry making an outgoing connection
 108   - Deactivate the host
 109 */
 110 void terminate_connection(connection_t *c, bool report) {
 111         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Closing connection with %s (%s)",
 112                            c->name, c->hostname);
 113
 114         c->status.active = false;
 115
 116         if(c->node)
 117                 c->node->connection = NULL;
 118
 119         if(c->socket)
 120                 closesocket(c->socket);
 121
 122         if(c->edge) {
 123                 if(report && !tunnelserver)
 124                         send_del_edge(broadcast, c->edge);
 125
 126                 edge_del(c->edge);
 127
 128                 /* Run MST and SSSP algorithms */
 129
 130                 graph();
 131
 132                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 133
 134                 if(report && !c->node->status.reachable) {
 135                         edge_t *e;
 136                         e = lookup_edge(c->node, myself);
 137                         if(e) {
 138                                 if(!tunnelserver)
 139                                         send_del_edge(broadcast, e);
 140                                 edge_del(e);
 141                         }
 142                 }
 143         }
 144
 145         /* Check if this was our outgoing connection */
 146
 147         if(c->outgoing)
 148                 retry_outgoing(c->outgoing);
 149
 150         connection_del(c);
 151 }
 152
 153 /*
 154   Check if the other end is active.
 155   If we have sent packets, but didn't receive any,
 156   then possibly the other end is dead. We send a
 157   PING request over the meta connection. If the other
 158   end does not reply in time, we consider them dead
 159   and close the connection.
 160 */
 161 static void timeout_handler(void *arg) {
 162         event_t *event = arg;
 163         splay_node_t *node, *next;
 164         connection_t *c;
 165         time_t now = time(NULL);
 166
 167         for(node = connection_tree->head; node; node = next) {
 168                 next = node->next;
 169                 c = node->data;
 170
 171                 if(c->last_ping_time + pingtimeout < now) {
 172                         if(c->status.active) {
 173                                 if(c->status.pinged) {
 174                                         ifdebug(CONNECTIONS) logger(LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
 175                                                            c->name, c->hostname, now - c->last_ping_time);
 176                                         terminate_connection(c, true);
 177                                         continue;
 178                                 } else if(c->last_ping_time + pinginterval < now) {
 179                                         send_ping(c);
 180                                 }
 181                         } else {
 182                                 if(c->status.connecting) {
 183                                         ifdebug(CONNECTIONS)
 184                                                 logger(LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 185                                         c->status.connecting = false;
 186                                         closesocket(c->socket);
 187                                         do_outgoing_connection(c);
 188                                 } else {
 189                                         ifdebug(CONNECTIONS) logger(LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 190                                         terminate_connection(c, false);
 191                                         continue;
 192                                 }
 193                         }
 194                 }
 195         }
 196
 197         if(contradicting_del_edge && contradicting_add_edge) {
 198                 logger(LOG_WARNING, "Possible node with same Name as us!");
 199
 200                 if(rand() % 3 == 0) {
 201                         logger(LOG_ERR, "Shutting down, check configuration of all nodes for duplicate Names!");
 202                         abort();
 203                         return;
 204                 }
 205
 206                 contradicting_add_edge = 0;
 207                 contradicting_del_edge = 0;
 208         }
 209
 210         event->time = now + pingtimeout;
 211         event_add(event);
 212 }
 213
 214 void handle_meta_connection_data(void *data) {
 215         connection_t *c = data;
 216         int result;
 217         socklen_t len = sizeof result;
 218
 219         if(c->status.connecting) {
 220                 c->status.connecting = false;
 221
 222                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 223
 224                 if(!result) {
 225                         mutex_lock(&mutex);
 226                         finish_connecting(c);
 227                         mutex_unlock(&mutex);
 228                 } else {
 229                         ifdebug(CONNECTIONS) logger(LOG_DEBUG,
 230                                            "Error while connecting to %s (%s): %s",
 231                                            c->name, c->hostname, sockstrerror(result));
 232                         closesocket(c->socket);
 233                         mutex_lock(&mutex);
 234                         do_outgoing_connection(c);
 235                         mutex_unlock(&mutex);
 236                         return;
 237                 }
 238         }
 239
 240         while(true) {
 241                 if (!receive_meta(c)) {
 242                         terminate_connection(c, c->status.active);
 243                         break;
 244                 }
 245         }
 246 }
 247
 248 int reload_configuration(void) {
 249         connection_t *c;
 250         splay_node_t *node, *next;
 251         char *fname;
 252         struct stat s;
 253         static time_t last_config_check = 0;
 254
 255         /* Reread our own configuration file */
 256
 257         exit_configuration(&config_tree);
 258         init_configuration(&config_tree);
 259
 260         if(!read_server_config()) {
 261                 logger(LOG_ERR, "Unable to reread configuration file, exitting.");
 262                 abort();
 263                 return EINVAL;
 264         }
 265
 266         /* Close connections to hosts that have a changed or deleted host config file */
 267
 268         for(node = connection_tree->head; node; node = next) {
 269                 c = node->data;
 270                 next = node->next;
 271
 272                 if(c->outgoing) {
 273                         free(c->outgoing->name);
 274                         if(c->outgoing->ai)
 275                                 freeaddrinfo(c->outgoing->ai);
 276                         free(c->outgoing);
 277                         c->outgoing = NULL;
 278                 }
 279
 280                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 281                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 282                         terminate_connection(c, c->status.active);
 283                 free(fname);
 284         }
 285
 286         last_config_check = time(NULL);
 287
 288         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 289
 290         if(strictsubnets) {
 291                 subnet_t *subnet;
 292
 293
 294                 for(node = subnet_tree->head; node; node = node->next) {
 295                         subnet = node->data;
 296                         subnet->expires = 1;
 297                 }
 298
 299                 load_all_subnets();
 300
 301                 for(node = subnet_tree->head; node; node = next) {
 302                         next = node->next;
 303                         subnet = node->data;
 304                         if(subnet->expires == 1) {
 305                                 send_del_subnet(broadcast, subnet);
 306                                 if(subnet->owner->status.reachable)
 307                                         subnet_update(subnet->owner, subnet, false);
 308                                 subnet_del(subnet->owner, subnet);
 309                         } else if(subnet->expires == -1) {
 310                                 subnet->expires = 0;
 311                         } else {
 312                                 send_add_subnet(broadcast, subnet);
 313                                 if(subnet->owner->status.reachable)
 314                                         subnet_update(subnet->owner, subnet, true);
 315                         }
 316                 }
 317         }
 318
 319         /* Try to make outgoing connections */
 320
 321         try_outgoing_connections();
 322
 323         return 0;
 324 }
 325
 326 void retry(void) {
 327         connection_t *c;
 328         splay_node_t *node;
 329
 330         for(node = connection_tree->head; node; node = node->next) {
 331                 c = node->data;
 332
 333                 if(c->outgoing && !c->node) {
 334                         event_del(&c->outgoing->ev);
 335                         if(c->status.connecting)
 336                                 close(c->socket);
 337                         c->outgoing->timeout = 0;
 338                         do_outgoing_connection(c);
 339                 }
 340         }
 341 }
 342
 343 /*
 344   this is where it all happens...
 345 */
 346 int main_loop(void) {
 347         struct event timeout_event;
 348
 349         timeout_event.time = time(NULL) + pingtimeout;
 350         timeout_event.handler = timeout_handler;
 351         timeout_event.data = &timeout_event;
 352
 353         event_add(&timeout_event);
 354
 355
 356         while(true) {
 357                 mutex_unlock(&mutex);
 358                 usleep(1000000);
 359                 mutex_lock(&mutex);
 360
 361                 struct event *event;
 362                 while((event = get_expired_event())) {
 363                         event->handler(event->data);
 364                 }
 365         }
 366
 367         event_del(&timeout_event);
 368
 369         return 0;
 370 }