tinc-vpn.org Git - tinc/blob - src/net.c

   1 /*
   2     net.c -- most of the network code
   3     Copyright (C) 1998-2005 Ivo Timmermans,
   4                   2000-2006 Guus Sliepen <guus@tinc-vpn.org>
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20     $Id$
  21 */
  22
  23 #include "system.h"
  24
  25 #include <openssl/rand.h>
  26
  27 #include "utils.h"
  28 #include "avl_tree.h"
  29 #include "conf.h"
  30 #include "connection.h"
  31 #include "device.h"
  32 #include "graph.h"
  33 #include "logger.h"
  34 #include "meta.h"
  35 #include "net.h"
  36 #include "netutl.h"
  37 #include "process.h"
  38 #include "protocol.h"
  39 #include "subnet.h"
  40 #include "xalloc.h"
  41
  42 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  43
  44 static void purge(void) {
  45         avl_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
  46         node_t *n;
  47         edge_t *e;
  48         subnet_t *s;
  49
  50         cp();
  51
  52         ifdebug(PROTOCOL) logger(LOG_DEBUG, _("Purging unreachable nodes"));
  53
  54         /* Remove all edges and subnets owned by unreachable nodes. */
  55
  56         for(nnode = node_tree->head; nnode; nnode = nnext) {
  57                 nnext = nnode->next;
  58                 n = nnode->data;
  59
  60                 if(!n->status.reachable) {
  61                         ifdebug(SCARY_THINGS) logger(LOG_DEBUG, _("Purging node %s (%s)"), n->name,
  62                                            n->hostname);
  63
  64                         for(snode = n->subnet_tree->head; snode; snode = snext) {
  65                                 snext = snode->next;
  66                                 s = snode->data;
  67                                 if(!tunnelserver)
  68                                         send_del_subnet(broadcast, s);
  69                                 subnet_del(n, s);
  70                         }
  71
  72                         for(enode = n->edge_tree->head; enode; enode = enext) {
  73                                 enext = enode->next;
  74                                 e = enode->data;
  75                                 if(!tunnelserver)
  76                                         send_del_edge(broadcast, e);
  77                                 edge_del(e);
  78                         }
  79                 }
  80         }
  81
  82         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  83
  84         for(nnode = node_tree->head; nnode; nnode = nnext) {
  85                 nnext = nnode->next;
  86                 n = nnode->data;
  87
  88                 if(!n->status.reachable) {
  89                         for(enode = edge_weight_tree->head; enode; enode = enext) {
  90                                 enext = enode->next;
  91                                 e = enode->data;
  92
  93                                 if(e->to == n)
  94                                         break;
  95                         }
  96
  97                         if(!enode)
  98                                 node_del(n);
  99                 }
 100         }
 101 }
 102
 103 /*
 104   put all file descriptors into events
 105   While we're at it, purge stuf that needs to be removed.
 106 */
 107 static int build_fdset(void) {
 108         avl_node_t *node, *next;
 109         connection_t *c;
 110         int i, max = 0;
 111
 112         cp();
 113
 114         for(node = connection_tree->head; node; node = next) {
 115                 next = node->next;
 116                 c = node->data;
 117
 118                 if(c->status.remove) {
 119                         connection_del(c);
 120                         if(!connection_tree->head)
 121                                 purge();
 122                 }
 123         }
 124
 125         return 0;
 126 }
 127
 128 /*
 129   Terminate a connection:
 130   - Close the socket
 131   - Remove associated edge and tell other connections about it if report = true
 132   - Check if we need to retry making an outgoing connection
 133   - Deactivate the host
 134 */
 135 void terminate_connection(connection_t *c, bool report) {
 136         cp();
 137
 138         if(c->status.remove)
 139                 return;
 140
 141         ifdebug(CONNECTIONS) logger(LOG_NOTICE, _("Closing connection with %s (%s)"),
 142                            c->name, c->hostname);
 143
 144         c->status.remove = true;
 145         c->status.active = false;
 146
 147         if(c->node)
 148                 c->node->connection = NULL;
 149
 150         if(c->socket)
 151                 closesocket(c->socket);
 152
 153         event_del(&c->ev);
 154
 155         if(c->edge) {
 156                 if(report && !tunnelserver)
 157                         send_del_edge(broadcast, c->edge);
 158
 159                 edge_del(c->edge);
 160
 161                 /* Run MST and SSSP algorithms */
 162
 163                 graph();
 164
 165                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 166
 167                 if(report && !c->node->status.reachable) {
 168                         edge_t *e;
 169                         e = lookup_edge(c->node, myself);
 170                         if(e) {
 171                                 if(!tunnelserver)
 172                                         send_del_edge(broadcast, e);
 173                                 edge_del(e);
 174                         }
 175                 }
 176         }
 177
 178         /* Check if this was our outgoing connection */
 179
 180         if(c->outgoing) {
 181                 retry_outgoing(c->outgoing);
 182                 c->outgoing = NULL;
 183         }
 184
 185         free(c->outbuf);
 186         c->outbuf = NULL;
 187         c->outbuflen = 0;
 188         c->outbufsize = 0;
 189         c->outbufstart = 0;
 190 }
 191
 192 /*
 193   Check if the other end is active.
 194   If we have sent packets, but didn't receive any,
 195   then possibly the other end is dead. We send a
 196   PING request over the meta connection. If the other
 197   end does not reply in time, we consider them dead
 198   and close the connection.
 199 */
 200 static void timeout_handler(int fd, short events, void *event) {
 201         avl_node_t *node, *next;
 202         connection_t *c;
 203         time_t now = time(NULL);
 204
 205         cp();
 206
 207         for(node = connection_tree->head; node; node = next) {
 208                 next = node->next;
 209                 c = node->data;
 210
 211                 if(c->last_ping_time + pingtimeout < now) {
 212                         if(c->status.active) {
 213                                 if(c->status.pinged) {
 214                                         ifdebug(CONNECTIONS) logger(LOG_INFO, _("%s (%s) didn't respond to PING in %ld seconds"),
 215                                                            c->name, c->hostname, now - c->last_ping_time);
 216                                         c->status.timeout = true;
 217                                         terminate_connection(c, true);
 218                                 } else if(c->last_ping_time + pinginterval < now) {
 219                                         send_ping(c);
 220                                 }
 221                         } else {
 222                                 if(c->status.remove) {
 223                                         logger(LOG_WARNING, _("Old connection_t for %s (%s) status %04x still lingering, deleting..."),
 224                                                    c->name, c->hostname, c->status.value);
 225                                         connection_del(c);
 226                                         continue;
 227                                 }
 228                                 ifdebug(CONNECTIONS) logger(LOG_WARNING, _("Timeout from %s (%s) during authentication"),
 229                                                    c->name, c->hostname);
 230                                 if(c->status.connecting) {
 231                                         c->status.connecting = false;
 232                                         closesocket(c->socket);
 233                                         do_outgoing_connection(c);
 234                                 } else {
 235                                         terminate_connection(c, false);
 236                                 }
 237                         }
 238                 }
 239         }
 240
 241         event_add(event, &(struct timeval){pingtimeout, 0});
 242 }
 243
 244 void handle_meta_connection_data(int fd, short events, void *data) {
 245         connection_t *c = data;
 246         int result;
 247         socklen_t len = sizeof(result);
 248
 249         if (c->status.remove)
 250                 return;
 251
 252         if(c->status.connecting) {
 253                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 254
 255                 if(!result)
 256                         finish_connecting(c);
 257                 else {
 258                         ifdebug(CONNECTIONS) logger(LOG_DEBUG,
 259                                            _("Error while connecting to %s (%s): %s"),
 260                                            c->name, c->hostname, strerror(result));
 261                         c->status.connecting = false;
 262                         closesocket(c->socket);
 263                         do_outgoing_connection(c);
 264                         return;
 265                 }
 266         }
 267
 268         if (!receive_meta(c)) {
 269                 terminate_connection(c, c->status.active);
 270                 return;
 271         }
 272 }
 273
 274 static void sigterm_handler(int signal, short events, void *data) {
 275         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 276         event_loopexit(NULL);
 277 }
 278
 279 static void sigint_handler(int signal, short events, void *data) {
 280         static int saved_debug_level = -1;
 281
 282         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 283
 284         if(saved_debug_level != -1) {
 285                 logger(LOG_NOTICE, _("Reverting to old debug level (%d)"),
 286                         saved_debug_level);
 287                 debug_level = saved_debug_level;
 288                 saved_debug_level = -1;
 289         } else {
 290                 logger(LOG_NOTICE,
 291                         _("Temporarily setting debug level to 5.  Kill me with SIGINT again to go back to level %d."),
 292                         debug_level);
 293                 saved_debug_level = debug_level;
 294                 debug_level = 5;
 295         }
 296 }
 297
 298 static void sigusr1_handler(int signal, short events, void *data) {
 299         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 300         dump_connections();
 301 }
 302
 303 static void sigusr2_handler(int signal, short events, void *data) {
 304         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 305         dump_device_stats();
 306         dump_nodes();
 307         dump_edges();
 308         dump_subnets();
 309 }
 310
 311 static void sigwinch_handler(int signal, short events, void *data) {
 312         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 313         purge();
 314 }
 315
 316 static void sighup_handler(int signal, short events, void *data) {
 317         connection_t *c;
 318         avl_node_t *node;
 319         char *fname;
 320         struct stat s;
 321         static time_t last_config_check = 0;
 322
 323         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 324
 325         /* Reread our own configuration file */
 326
 327         exit_configuration(&config_tree);
 328         init_configuration(&config_tree);
 329
 330         if(!read_server_config()) {
 331                 logger(LOG_ERR, _("Unable to reread configuration file, exitting."));
 332                 event_loopexit(NULL);
 333                 return;
 334         }
 335
 336         /* Close connections to hosts that have a changed or deleted host config file */
 337
 338         for(node = connection_tree->head; node; node = node->next) {
 339                 c = node->data;
 340
 341                 if(c->outgoing) {
 342                         free(c->outgoing->name);
 343                         if(c->outgoing->ai)
 344                                 freeaddrinfo(c->outgoing->ai);
 345                         free(c->outgoing);
 346                         c->outgoing = NULL;
 347                 }
 348
 349                 asprintf(&fname, "%s/hosts/%s", confbase, c->name);
 350                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 351                         terminate_connection(c, c->status.active);
 352                 free(fname);
 353         }
 354
 355         last_config_check = time(NULL);
 356
 357         /* Try to make outgoing connections */
 358
 359         try_outgoing_connections();
 360 }
 361
 362 static void sigalrm_handler(int signal, short events, void *data) {
 363         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 364
 365         connection_t *c;
 366         avl_node_t *node;
 367
 368         for(node = connection_tree->head; node; node = node->next) {
 369                 c = node->data;
 370
 371                 if(c->outgoing && !c->node) {
 372                         if(timeout_initialized(&c->outgoing->ev))
 373                                 event_del(&c->outgoing->ev);
 374                         if(c->status.connecting)
 375                                 close(c->socket);
 376                         c->outgoing->timeout = 0;
 377                         do_outgoing_connection(c);
 378                 }
 379         }
 380 }
 381
 382 /*
 383   this is where it all happens...
 384 */
 385 int main_loop(void) {
 386         struct timeval tv;
 387         int r;
 388         struct event timeout_event;
 389         struct event sighup_event;
 390         struct event sigint_event;
 391         struct event sigterm_event;
 392         struct event sigquit_event;
 393         struct event sigusr1_event;
 394         struct event sigusr2_event;
 395         struct event sigwinch_event;
 396         struct event sigalrm_event;
 397
 398         cp();
 399
 400         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 401         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 402         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 403         signal_add(&sighup_event, NULL);
 404         signal_set(&sigint_event, SIGINT, sigint_handler, NULL);
 405         signal_add(&sigint_event, NULL);
 406         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 407         signal_add(&sigterm_event, NULL);
 408         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 409         signal_add(&sigquit_event, NULL);
 410         signal_set(&sigusr1_event, SIGUSR1, sigusr1_handler, NULL);
 411         signal_add(&sigusr1_event, NULL);
 412         signal_set(&sigusr2_event, SIGUSR2, sigusr2_handler, NULL);
 413         signal_add(&sigusr2_event, NULL);
 414         signal_set(&sigwinch_event, SIGWINCH, sigwinch_handler, NULL);
 415         signal_add(&sigwinch_event, NULL);
 416         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 417         signal_add(&sigalrm_event, NULL);
 418
 419         if(event_loop(0) < 0) {
 420                 logger(LOG_ERR, _("Error while waiting for input: %s"), strerror(errno));
 421                 return 1;
 422         }
 423
 424         signal_del(&sighup_event);
 425         signal_del(&sigint_event);
 426         signal_del(&sigterm_event);
 427         signal_del(&sigquit_event);
 428         signal_del(&sigusr1_event);
 429         signal_del(&sigusr2_event);
 430         signal_del(&sigwinch_event);
 431         signal_del(&sigalrm_event);
 432         event_del(&timeout_event);
 433
 434         return 0;
 435 }