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