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                   2000-2012 Guus Sliepen <guus@tinc-vpn.org>
   5                   2006      Scott Lamb <slamb@slamb.org>
   6                   2011      Loïc Grenié <loic.grenie@gmail.com>
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License along
  19     with this program; if not, write to the Free Software Foundation, Inc.,
  20     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21 */
  22
  23 #include "system.h"
  24
  25 #include "utils.h"
  26 #include "splay_tree.h"
  27 #include "conf.h"
  28 #include "connection.h"
  29 #include "device.h"
  30 #include "graph.h"
  31 #include "logger.h"
  32 #include "meta.h"
  33 #include "net.h"
  34 #include "netutl.h"
  35 #include "process.h"
  36 #include "protocol.h"
  37 #include "subnet.h"
  38 #include "xalloc.h"
  39
  40 int contradicting_add_edge = 0;
  41 int contradicting_del_edge = 0;
  42 static int sleeptime = 10;
  43 time_t last_config_check = 0;
  44
  45 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  46
  47 void purge(void) {
  48         splay_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
  49         node_t *n;
  50         edge_t *e;
  51         subnet_t *s;
  52
  53         logger(DEBUG_PROTOCOL, 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                         logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Purging node %s (%s)", n->name, n->hostname);
  63
  64                         for(snode = n->subnet_tree->head; snode; snode = snext) {
  65                                 snext = snode->next;
  66                                 s = snode->data;
  67                                 send_del_subnet(everyone, s);
  68                                 if(!strictsubnets)
  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(everyone, 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 && (!strictsubnets || !n->subnet_tree->head))
  98                                 /* in strictsubnets mode do not delete nodes with subnets */
  99                                 node_del(n);
 100                 }
 101         }
 102 }
 103
 104 /*
 105   Terminate a connection:
 106   - Mark it as inactive
 107   - Remove the edge representing this connection
 108   - Kill it with fire
 109   - Check if we need to retry making an outgoing connection
 110 */
 111 void terminate_connection(connection_t *c, bool report) {
 112         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)", c->name, c->hostname);
 113
 114         c->status.active = false;
 115
 116         if(c->node && c->node->connection == c)
 117                 c->node->connection = NULL;
 118
 119         if(c->edge) {
 120                 if(report && !tunnelserver)
 121                         send_del_edge(everyone, c->edge);
 122
 123                 edge_del(c->edge);
 124                 c->edge = NULL;
 125
 126                 /* Run MST and SSSP algorithms */
 127
 128                 graph();
 129
 130                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 131
 132                 if(report && !c->node->status.reachable) {
 133                         edge_t *e;
 134                         e = lookup_edge(c->node, myself);
 135                         if(e) {
 136                                 if(!tunnelserver)
 137                                         send_del_edge(everyone, e);
 138                                 edge_del(e);
 139                         }
 140                 }
 141         }
 142
 143         outgoing_t *outgoing = c->outgoing;
 144         connection_del(c);
 145
 146         /* Check if this was our outgoing connection */
 147
 148         if(outgoing)
 149                 do_outgoing_connection(outgoing);
 150 }
 151
 152 /*
 153   Check if the other end is active.
 154   If we have sent packets, but didn't receive any,
 155   then possibly the other end is dead. We send a
 156   PING request over the meta connection. If the other
 157   end does not reply in time, we consider them dead
 158   and close the connection.
 159 */
 160 static void timeout_handler(int fd, short events, void *event) {
 161         splay_node_t *node, *next;
 162         connection_t *c;
 163         time_t now = time(NULL);
 164
 165         for(node = connection_tree->head; node; node = next) {
 166                 next = node->next;
 167                 c = node->data;
 168
 169                 if(c->status.control)
 170                         continue;
 171
 172                 if(c->last_ping_time + pingtimeout <= now) {
 173                         if(c->status.active) {
 174                                 if(c->status.pinged) {
 175                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds", c->name, c->hostname, (long)now - c->last_ping_time);
 176                                 } else if(c->last_ping_time + pinginterval <= now) {
 177                                         send_ping(c);
 178                                         continue;
 179                                 } else {
 180                                         continue;
 181                                 }
 182                         } else {
 183                                 if(c->status.connecting)
 184                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 185                                 else
 186                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 187                         }
 188                         terminate_connection(c, c->status.active);
 189                 }
 190         }
 191
 192         if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
 193                 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
 194                 usleep(sleeptime * 1000000LL);
 195                 sleeptime *= 2;
 196                 if(sleeptime < 0)
 197                         sleeptime = 3600;
 198         } else {
 199                 sleeptime /= 2;
 200                 if(sleeptime < 10)
 201                         sleeptime = 10;
 202         }
 203
 204         contradicting_add_edge = 0;
 205         contradicting_del_edge = 0;
 206
 207         event_add(event, &(struct timeval){pingtimeout, 0});
 208 }
 209
 210 void handle_meta_connection_data(int fd, short events, void *data) {
 211         connection_t *c = data;
 212         int result;
 213         socklen_t len = sizeof result;
 214
 215         if(c->status.connecting) {
 216                 c->status.connecting = false;
 217
 218                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 219
 220                 if(!result)
 221                         finish_connecting(c);
 222                 else {
 223                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(result));
 224                         terminate_connection(c, false);
 225                         return;
 226                 }
 227         }
 228
 229         if (!receive_meta(c)) {
 230                 terminate_connection(c, c->status.active);
 231                 return;
 232         }
 233 }
 234
 235 static void sigterm_handler(int signal, short events, void *data) {
 236         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 237         event_loopexit(NULL);
 238 }
 239
 240 static void sighup_handler(int signal, short events, void *data) {
 241         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 242         reopenlogger();
 243         reload_configuration();
 244 }
 245
 246 static void sigalrm_handler(int signal, short events, void *data) {
 247         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 248         retry();
 249 }
 250
 251 int reload_configuration(void) {
 252         connection_t *c;
 253         splay_node_t *node, *next;
 254         char *fname;
 255         struct stat s;
 256
 257         /* Reread our own configuration file */
 258
 259         exit_configuration(&config_tree);
 260         init_configuration(&config_tree);
 261
 262         if(!read_server_config()) {
 263                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file, exitting.");
 264                 event_loopexit(NULL);
 265                 return EINVAL;
 266         }
 267
 268         read_config_options(config_tree, NULL);
 269
 270         xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, myself->name);
 271         read_config_file(config_tree, fname);
 272         free(fname);
 273
 274         /* Parse some options that are allowed to be changed while tinc is running */
 275
 276         setup_myself_reloadable();
 277
 278         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 279
 280         if(strictsubnets) {
 281                 subnet_t *subnet;
 282
 283                 for(node = subnet_tree->head; node; node = node->next) {
 284                         subnet = node->data;
 285                         subnet->expires = 1;
 286                 }
 287
 288                 load_all_subnets();
 289
 290                 for(node = subnet_tree->head; node; node = next) {
 291                         next = node->next;
 292                         subnet = node->data;
 293                         if(subnet->expires == 1) {
 294                                 send_del_subnet(everyone, subnet);
 295                                 if(subnet->owner->status.reachable)
 296                                         subnet_update(subnet->owner, subnet, false);
 297                                 subnet_del(subnet->owner, subnet);
 298                         } else if(subnet->expires == -1) {
 299                                 subnet->expires = 0;
 300                         } else {
 301                                 send_add_subnet(everyone, subnet);
 302                                 if(subnet->owner->status.reachable)
 303                                         subnet_update(subnet->owner, subnet, true);
 304                         }
 305                 }
 306         } else { /* Only read our own subnets back in */
 307                 subnet_t *subnet, *s2;
 308
 309                 for(node = myself->subnet_tree->head; node; node = node->next) {
 310                         subnet_t *subnet = node->data;
 311                         if(!subnet->expires)
 312                                 subnet->expires = 1;
 313                 }
 314
 315                 config_t *cfg = lookup_config(config_tree, "Subnet");
 316
 317                 while(cfg) {
 318                         if(!get_config_subnet(cfg, &subnet))
 319                                 continue;
 320
 321                         if((s2 = lookup_subnet(myself, subnet))) {
 322                                 if(s2->expires == 1)
 323                                         s2->expires = 0;
 324
 325                                 free_subnet(subnet);
 326                         } else {
 327                                 subnet_add(myself, subnet);
 328                                 send_add_subnet(everyone, subnet);
 329                                 subnet_update(myself, subnet, true);
 330                         }
 331
 332                         cfg = lookup_config_next(config_tree, cfg);
 333                 }
 334
 335                 for(node = myself->subnet_tree->head; node; node = next) {
 336                         next = node->next;
 337                         subnet_t *subnet = node->data;
 338                         if(subnet->expires == 1) {
 339                                 send_del_subnet(everyone, subnet);
 340                                 subnet_update(myself, subnet, false);
 341                                 subnet_del(myself, subnet);
 342                         }
 343                 }
 344         }
 345
 346         /* Try to make outgoing connections */
 347
 348         try_outgoing_connections();
 349
 350         /* Close connections to hosts that have a changed or deleted host config file */
 351
 352         for(node = connection_tree->head; node; node = next) {
 353                 c = node->data;
 354                 next = node->next;
 355
 356                 if(c->status.control)
 357                         continue;
 358
 359                 xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
 360                 if(stat(fname, &s) || s.st_mtime > last_config_check) {
 361                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Host config file of %s has been changed", c->name);
 362                         terminate_connection(c, c->status.active);
 363                 }
 364                 free(fname);
 365         }
 366
 367         last_config_check = time(NULL);
 368
 369         return 0;
 370 }
 371
 372 void retry(void) {
 373         connection_t *c;
 374         splay_node_t *node, *next;
 375
 376         for(node = connection_tree->head; node; node = next) {
 377                 next = node->next;
 378                 c = node->data;
 379
 380                 if(c->outgoing && !c->node) {
 381                         if(timeout_initialized(&c->outgoing->ev))
 382                                 event_del(&c->outgoing->ev);
 383                         if(c->status.connecting)
 384                                 close(c->socket);
 385                         c->outgoing->timeout = 0;
 386                         terminate_connection(c, c->status.active);
 387                 }
 388         }
 389 }
 390
 391 /*
 392   this is where it all happens...
 393 */
 394 int main_loop(void) {
 395         struct event timeout_event;
 396
 397         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 398         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 399
 400 #ifndef HAVE_MINGW
 401         struct event sighup_event;
 402         struct event sigterm_event;
 403         struct event sigquit_event;
 404         struct event sigalrm_event;
 405
 406         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 407         signal_add(&sighup_event, NULL);
 408         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 409         signal_add(&sigterm_event, NULL);
 410         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 411         signal_add(&sigquit_event, NULL);
 412         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 413         signal_add(&sigalrm_event, NULL);
 414 #endif
 415
 416         if(event_loop(0) < 0) {
 417                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 418                 return 1;
 419         }
 420
 421 #ifndef HAVE_MINGW
 422         signal_del(&sighup_event);
 423         signal_del(&sigterm_event);
 424         signal_del(&sigquit_event);
 425         signal_del(&sigalrm_event);
 426 #endif
 427
 428         event_del(&timeout_event);
 429
 430         return 0;
 431 }