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 volatile bool running = false;
  43
  44 time_t now = 0;
  45
  46 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  47
  48 static void purge(void)
  49 {
  50         avl_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
  51         node_t *n;
  52         edge_t *e;
  53         subnet_t *s;
  54
  55         cp();
  56
  57         ifdebug(PROTOCOL) logger(LOG_DEBUG, _("Purging unreachable nodes"));
  58
  59         /* Remove all edges and subnets owned by unreachable nodes. */
  60
  61         for(nnode = node_tree->head; nnode; nnode = nnext) {
  62                 nnext = nnode->next;
  63                 n = nnode->data;
  64
  65                 if(!n->status.reachable) {
  66                         ifdebug(SCARY_THINGS) logger(LOG_DEBUG, _("Purging node %s (%s)"), n->name,
  67                                            n->hostname);
  68
  69                         for(snode = n->subnet_tree->head; snode; snode = snext) {
  70                                 snext = snode->next;
  71                                 s = snode->data;
  72                                 if(!tunnelserver)
  73                                         send_del_subnet(broadcast, s);
  74                                 subnet_del(n, s);
  75                         }
  76
  77                         for(enode = n->edge_tree->head; enode; enode = enext) {
  78                                 enext = enode->next;
  79                                 e = enode->data;
  80                                 if(!tunnelserver)
  81                                         send_del_edge(broadcast, e);
  82                                 edge_del(e);
  83                         }
  84                 }
  85         }
  86
  87         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  88
  89         for(nnode = node_tree->head; nnode; nnode = nnext) {
  90                 nnext = nnode->next;
  91                 n = nnode->data;
  92
  93                 if(!n->status.reachable) {
  94                         for(enode = edge_weight_tree->head; enode; enode = enext) {
  95                                 enext = enode->next;
  96                                 e = enode->data;
  97
  98                                 if(e->to == n)
  99                                         break;
 100                         }
 101
 102                         if(!enode)
 103                                 node_del(n);
 104                 }
 105         }
 106 }
 107
 108 /*
 109   put all file descriptors into events
 110   While we're at it, purge stuf that needs to be removed.
 111 */
 112 static int build_fdset(void)
 113 {
 114         avl_node_t *node, *next;
 115         connection_t *c;
 116         int i, max = 0;
 117
 118         cp();
 119
 120         for(node = connection_tree->head; node; node = next) {
 121                 next = node->next;
 122                 c = node->data;
 123
 124                 if(c->status.remove) {
 125                         connection_del(c);
 126                         if(!connection_tree->head)
 127                                 purge();
 128                 }
 129         }
 130
 131         return 0;
 132 }
 133
 134 /*
 135   Terminate a connection:
 136   - Close the socket
 137   - Remove associated edge and tell other connections about it if report = true
 138   - Check if we need to retry making an outgoing connection
 139   - Deactivate the host
 140 */
 141 void terminate_connection(connection_t *c, bool report)
 142 {
 143         cp();
 144
 145         if(c->status.remove)
 146                 return;
 147
 148         ifdebug(CONNECTIONS) logger(LOG_NOTICE, _("Closing connection with %s (%s)"),
 149                            c->name, c->hostname);
 150
 151         c->status.remove = true;
 152         c->status.active = false;
 153
 154         if(c->node)
 155                 c->node->connection = NULL;
 156
 157         if(c->socket)
 158                 closesocket(c->socket);
 159
 160         event_del(&c->ev);
 161
 162         if(c->edge) {
 163                 if(report && !tunnelserver)
 164                         send_del_edge(broadcast, c->edge);
 165
 166                 edge_del(c->edge);
 167
 168                 /* Run MST and SSSP algorithms */
 169
 170                 graph();
 171
 172                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 173
 174                 if(report && !c->node->status.reachable) {
 175                         edge_t *e;
 176                         e = lookup_edge(c->node, myself);
 177                         if(e) {
 178                                 if(!tunnelserver)
 179                                         send_del_edge(broadcast, e);
 180                                 edge_del(e);
 181                         }
 182                 }
 183         }
 184
 185         /* Check if this was our outgoing connection */
 186
 187         if(c->outgoing) {
 188                 retry_outgoing(c->outgoing);
 189                 c->outgoing = NULL;
 190         }
 191
 192         free(c->outbuf);
 193         c->outbuf = NULL;
 194         c->outbuflen = 0;
 195         c->outbufsize = 0;
 196         c->outbufstart = 0;
 197 }
 198
 199 /*
 200   Check if the other end is active.
 201   If we have sent packets, but didn't receive any,
 202   then possibly the other end is dead. We send a
 203   PING request over the meta connection. If the other
 204   end does not reply in time, we consider them dead
 205   and close the connection.
 206 */
 207 static void check_dead_connections(void)
 208 {
 209         avl_node_t *node, *next;
 210         connection_t *c;
 211
 212         cp();
 213
 214         for(node = connection_tree->head; node; node = next) {
 215                 next = node->next;
 216                 c = node->data;
 217
 218                 if(c->last_ping_time + pingtimeout < now) {
 219                         if(c->status.active) {
 220                                 if(c->status.pinged) {
 221                                         ifdebug(CONNECTIONS) logger(LOG_INFO, _("%s (%s) didn't respond to PING in %ld seconds"),
 222                                                            c->name, c->hostname, now - c->last_ping_time);
 223                                         c->status.timeout = true;
 224                                         terminate_connection(c, true);
 225                                 } else if(c->last_ping_time + pinginterval < now) {
 226                                         send_ping(c);
 227                                 }
 228                         } else {
 229                                 if(c->status.remove) {
 230                                         logger(LOG_WARNING, _("Old connection_t for %s (%s) status %04x still lingering, deleting..."),
 231                                                    c->name, c->hostname, c->status.value);
 232                                         connection_del(c);
 233                                         continue;
 234                                 }
 235                                 ifdebug(CONNECTIONS) logger(LOG_WARNING, _("Timeout from %s (%s) during authentication"),
 236                                                    c->name, c->hostname);
 237                                 if(c->status.connecting) {
 238                                         c->status.connecting = false;
 239                                         closesocket(c->socket);
 240                                         do_outgoing_connection(c);
 241                                 } else {
 242                                         terminate_connection(c, false);
 243                                 }
 244                         }
 245                 }
 246
 247                 if(c->outbuflen > 0 && c->last_flushed_time + pingtimeout < now) {
 248                         if(c->status.active) {
 249                                 ifdebug(CONNECTIONS) logger(LOG_INFO,
 250                                                 _("%s (%s) could not flush for %ld seconds (%d bytes remaining)"),
 251                                                 c->name, c->hostname, now - c->last_flushed_time, c->outbuflen);
 252                                 c->status.timeout = true;
 253                                 terminate_connection(c, true);
 254                         }
 255                 }
 256         }
 257 }
 258
 259 void handle_meta_connection_data(int fd, short events, void *data)
 260 {
 261         connection_t *c = data;
 262         int result;
 263         socklen_t len = sizeof(result);
 264
 265         if (c->status.remove)
 266                 return;
 267
 268         if(c->status.connecting) {
 269                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 270
 271                 if(!result)
 272                         finish_connecting(c);
 273                 else {
 274                         ifdebug(CONNECTIONS) logger(LOG_DEBUG,
 275                                            _("Error while connecting to %s (%s): %s"),
 276                                            c->name, c->hostname, strerror(result));
 277                         c->status.connecting = false;
 278                         closesocket(c->socket);
 279                         do_outgoing_connection(c);
 280                         return;
 281                 }
 282         }
 283
 284         if (!receive_meta(c)) {
 285                 terminate_connection(c, c->status.active);
 286                 return;
 287         }
 288 }
 289
 290 static void dummy(int a, short b, void *c)
 291 {
 292 }
 293
 294 static void sigterm_handler(int signal, short events, void *data) {
 295         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 296         running = false;
 297         event_loopexit(NULL);
 298 }
 299
 300 static void sigint_handler(int signal, short events, void *data) {
 301         static int saved_debug_level = -1;
 302
 303         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 304
 305         if(saved_debug_level != -1) {
 306                 logger(LOG_NOTICE, _("Reverting to old debug level (%d)"),
 307                         saved_debug_level);
 308                 debug_level = saved_debug_level;
 309                 saved_debug_level = -1;
 310         } else {
 311                 logger(LOG_NOTICE,
 312                         _("Temporarily setting debug level to 5.  Kill me with SIGINT again to go back to level %d."),
 313                         debug_level);
 314                 saved_debug_level = debug_level;
 315                 debug_level = 5;
 316         }
 317 }
 318
 319 static void sigusr1_handler(int signal, short events, void *data) {
 320         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 321         dump_connections();
 322 }
 323
 324 static void sigusr2_handler(int signal, short events, void *data) {
 325         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 326         dump_device_stats();
 327         dump_nodes();
 328         dump_edges();
 329         dump_subnets();
 330 }
 331
 332 static void sigwinch_handler(int signal, short events, void *data) {
 333         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 334         purge();
 335 }
 336
 337 static void sighup_handler(int signal, short events, void *data) {
 338         connection_t *c;
 339         avl_node_t *node;
 340         char *fname;
 341         struct stat s;
 342         static time_t last_config_check = 0;
 343
 344         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 345
 346         /* Reread our own configuration file */
 347
 348         exit_configuration(&config_tree);
 349         init_configuration(&config_tree);
 350
 351         if(!read_server_config()) {
 352                 logger(LOG_ERR, _("Unable to reread configuration file, exitting."));
 353                 event_loopexit(NULL);
 354                 return;
 355         }
 356
 357         /* Close connections to hosts that have a changed or deleted host config file */
 358
 359         for(node = connection_tree->head; node; node = node->next) {
 360                 c = node->data;
 361
 362                 if(c->outgoing) {
 363                         free(c->outgoing->name);
 364                         if(c->outgoing->ai)
 365                                 freeaddrinfo(c->outgoing->ai);
 366                         free(c->outgoing);
 367                         c->outgoing = NULL;
 368                 }
 369
 370                 asprintf(&fname, "%s/hosts/%s", confbase, c->name);
 371                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 372                         terminate_connection(c, c->status.active);
 373                 free(fname);
 374         }
 375
 376         last_config_check = time(NULL);
 377
 378         /* Try to make outgoing connections */
 379
 380         try_outgoing_connections();
 381 }
 382
 383 static void sigalrm_handler(int signal, short events, void *data) {
 384         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 385
 386         connection_t *c;
 387         avl_node_t *node;
 388
 389         for(node = connection_tree->head; node; node = node->next) {
 390                 c = node->data;
 391
 392                 if(c->outgoing && !c->node) {
 393                         if(timeout_initialized(&c->outgoing->ev))
 394                                 event_del(&c->outgoing->ev);
 395                         if(c->status.connecting)
 396                                 close(c->socket);
 397                         c->outgoing->timeout = 0;
 398                         do_outgoing_connection(c);
 399                 }
 400         }
 401 }
 402
 403 /*
 404   this is where it all happens...
 405 */
 406 int main_loop(void)
 407 {
 408         struct timeval tv;
 409         int r;
 410         time_t last_ping_check;
 411         struct event timeout;
 412         struct event sighup_event;
 413         struct event sigint_event;
 414         struct event sigterm_event;
 415         struct event sigquit_event;
 416         struct event sigusr1_event;
 417         struct event sigusr2_event;
 418         struct event sigwinch_event;
 419         struct event sigalrm_event;
 420
 421         cp();
 422
 423         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 424         signal_add(&sighup_event, NULL);
 425         signal_set(&sigint_event, SIGINT, sigint_handler, NULL);
 426         signal_add(&sigint_event, NULL);
 427         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 428         signal_add(&sigterm_event, NULL);
 429         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 430         signal_add(&sigquit_event, NULL);
 431         signal_set(&sigusr1_event, SIGUSR1, sigusr1_handler, NULL);
 432         signal_add(&sigusr1_event, NULL);
 433         signal_set(&sigusr2_event, SIGUSR2, sigusr2_handler, NULL);
 434         signal_add(&sigusr2_event, NULL);
 435         signal_set(&sigwinch_event, SIGWINCH, sigwinch_handler, NULL);
 436         signal_add(&sigwinch_event, NULL);
 437         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 438         signal_add(&sigalrm_event, NULL);
 439
 440         last_ping_check = now;
 441
 442         srand(now);
 443
 444         running = true;
 445
 446         while(running) {
 447                 now = time(NULL);
 448
 449         //      tv.tv_sec = 1 + (rand() & 7);   /* Approx. 5 seconds, randomized to prevent global synchronisation effects */
 450                 tv.tv_sec = 1;
 451                 tv.tv_usec = 0;
 452
 453                 /* XXX: libevent transition: old timeout code in this loop */
 454                 timeout_set(&timeout, dummy, NULL);
 455                 timeout_add(&timeout, &tv);
 456
 457                 r = build_fdset();
 458                 if(r < 0) {
 459                         logger(LOG_ERR, _("Error building fdset: %s"), strerror(errno));
 460                         cp_trace();
 461                         dump_connections();
 462                         return 1;
 463                 }
 464
 465                 r = event_loop(EVLOOP_ONCE);
 466                 now = time(NULL);
 467                 if(r < 0) {
 468                         logger(LOG_ERR, _("Error while waiting for input: %s"),
 469                                    strerror(errno));
 470                         cp_trace();
 471                         dump_connections();
 472                         return 1;
 473                 }
 474
 475                 /* XXX: more libevent transition */
 476                 timeout_del(&timeout);
 477
 478                 /* Let's check if everybody is still alive */
 479
 480                 if(last_ping_check + pingtimeout < now) {
 481                         check_dead_connections();
 482                         last_ping_check = now;
 483                 }
 484         }
 485
 486         signal_del(&sighup_event);
 487         signal_del(&sigint_event);
 488         signal_del(&sigterm_event);
 489         signal_del(&sigquit_event);
 490         signal_del(&sigusr1_event);
 491         signal_del(&sigusr2_event);
 492         signal_del(&sigwinch_event);
 493         signal_del(&sigalrm_event);
 494
 495         return 0;
 496 }