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