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 "conf.h"
  27 #include "connection.h"
  28 #include "device.h"
  29 #include "graph.h"
  30 #include "logger.h"
  31 #include "meta.h"
  32 #include "net.h"
  33 #include "netutl.h"
  34 #include "process.h"
  35 #include "protocol.h"
  36 #include "subnet.h"
  37 #include "xalloc.h"
  38
  39 int contradicting_add_edge = 0;
  40 int contradicting_del_edge = 0;
  41 static int sleeptime = 10;
  42 time_t last_config_check = 0;
  43
  44 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  45
  46 void purge(void) {
  47         splay_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
  48         node_t *n;
  49         edge_t *e;
  50         subnet_t *s;
  51
  52         logger(DEBUG_PROTOCOL, 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                         logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Purging node %s (%s)", n->name, n->hostname);
  62
  63                         for(snode = n->subnet_tree->head; snode; snode = snext) {
  64                                 snext = snode->next;
  65                                 s = snode->data;
  66                                 send_del_subnet(everyone, s);
  67                                 if(!strictsubnets)
  68                                         subnet_del(n, s);
  69                         }
  70
  71                         for(enode = n->edge_tree->head; enode; enode = enext) {
  72                                 enext = enode->next;
  73                                 e = enode->data;
  74                                 if(!tunnelserver)
  75                                         send_del_edge(everyone, e);
  76                                 edge_del(e);
  77                         }
  78                 }
  79         }
  80
  81         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  82
  83         for(nnode = node_tree->head; nnode; nnode = nnext) {
  84                 nnext = nnode->next;
  85                 n = nnode->data;
  86
  87                 if(!n->status.reachable) {
  88                         for(enode = edge_weight_tree->head; enode; enode = enext) {
  89                                 enext = enode->next;
  90                                 e = enode->data;
  91
  92                                 if(e->to == n)
  93                                         break;
  94                         }
  95
  96                         if(!enode && (!strictsubnets || !n->subnet_tree->head))
  97                                 /* in strictsubnets mode do not delete nodes with subnets */
  98                                 node_del(n);
  99                 }
 100         }
 101 }
 102
 103 /*
 104   Terminate a connection:
 105   - Mark it as inactive
 106   - Remove the edge representing this connection
 107   - Kill it with fire
 108   - Check if we need to retry making an outgoing connection
 109 */
 110 void terminate_connection(connection_t *c, bool report) {
 111         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)", c->name, c->hostname);
 112
 113         c->status.active = false;
 114
 115         if(c->node && c->node->connection == c)
 116                 c->node->connection = NULL;
 117
 118         if(c->edge) {
 119                 if(report && !tunnelserver)
 120                         send_del_edge(everyone, c->edge);
 121
 122                 edge_del(c->edge);
 123                 c->edge = NULL;
 124
 125                 /* Run MST and SSSP algorithms */
 126
 127                 graph();
 128
 129                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 130
 131                 if(report && !c->node->status.reachable) {
 132                         edge_t *e;
 133                         e = lookup_edge(c->node, myself);
 134                         if(e) {
 135                                 if(!tunnelserver)
 136                                         send_del_edge(everyone, e);
 137                                 edge_del(e);
 138                         }
 139                 }
 140         }
 141
 142         outgoing_t *outgoing = c->outgoing;
 143         connection_del(c);
 144
 145         /* Check if this was our outgoing connection */
 146
 147         if(outgoing)
 148                 do_outgoing_connection(outgoing);
 149 }
 150
 151 /*
 152   Check if the other end is active.
 153   If we have sent packets, but didn't receive any,
 154   then possibly the other end is dead. We send a
 155   PING request over the meta connection. If the other
 156   end does not reply in time, we consider them dead
 157   and close the connection.
 158 */
 159 static void timeout_handler(int fd, short events, void *event) {
 160         time_t now = time(NULL);
 161
 162         for(list_node_t *node = connection_list->head, *next; node; node = next) {
 163                 next = node->next;
 164                 connection_t *c = node->data;
 165
 166                 if(c->status.control)
 167                         continue;
 168
 169                 if(c->last_ping_time + pingtimeout <= now) {
 170                         if(c->status.active) {
 171                                 if(c->status.pinged) {
 172                                         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);
 173                                 } else if(c->last_ping_time + pinginterval <= now) {
 174                                         send_ping(c);
 175                                         continue;
 176                                 } else {
 177                                         continue;
 178                                 }
 179                         } else {
 180                                 if(c->status.connecting)
 181                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 182                                 else
 183                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 184                         }
 185                         terminate_connection(c, c->status.active);
 186                 }
 187         }
 188
 189         if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
 190                 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
 191                 usleep(sleeptime * 1000000LL);
 192                 sleeptime *= 2;
 193                 if(sleeptime < 0)
 194                         sleeptime = 3600;
 195         } else {
 196                 sleeptime /= 2;
 197                 if(sleeptime < 10)
 198                         sleeptime = 10;
 199         }
 200
 201         contradicting_add_edge = 0;
 202         contradicting_del_edge = 0;
 203
 204         event_add(event, &(struct timeval){pingtimeout, 0});
 205 }
 206
 207 void handle_meta_connection_data(int fd, short events, void *data) {
 208         connection_t *c = data;
 209         int result;
 210         socklen_t len = sizeof result;
 211
 212         if(c->status.connecting) {
 213                 c->status.connecting = false;
 214
 215                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 216
 217                 if(!result)
 218                         finish_connecting(c);
 219                 else {
 220                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(result));
 221                         terminate_connection(c, false);
 222                         return;
 223                 }
 224         }
 225
 226         if (!receive_meta(c)) {
 227                 terminate_connection(c, c->status.active);
 228                 return;
 229         }
 230 }
 231
 232 static void sigterm_handler(int signal, short events, void *data) {
 233         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 234         event_loopexit(NULL);
 235 }
 236
 237 static void sighup_handler(int signal, short events, void *data) {
 238         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 239         reopenlogger();
 240         reload_configuration();
 241 }
 242
 243 static void sigalrm_handler(int signal, short events, void *data) {
 244         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 245         retry();
 246 }
 247
 248 int reload_configuration(void) {
 249         char *fname;
 250
 251         /* Reread our own configuration file */
 252
 253         exit_configuration(&config_tree);
 254         init_configuration(&config_tree);
 255
 256         if(!read_server_config()) {
 257                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file, exitting.");
 258                 event_loopexit(NULL);
 259                 return EINVAL;
 260         }
 261
 262         read_config_options(config_tree, NULL);
 263
 264         xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, myself->name);
 265         read_config_file(config_tree, fname);
 266         free(fname);
 267
 268         /* Parse some options that are allowed to be changed while tinc is running */
 269
 270         setup_myself_reloadable();
 271
 272         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 273
 274         if(strictsubnets) {
 275                 for(splay_node_t *node = subnet_tree->head; node; node = node->next) {
 276                         subnet_t *subnet = node->data;
 277                         subnet->expires = 1;
 278                 }
 279
 280                 load_all_subnets();
 281
 282                 for(splay_node_t *node = subnet_tree->head, *next; node; node = next) {
 283                         next = node->next;
 284                         subnet_t *subnet = node->data;
 285                         if(subnet->expires == 1) {
 286                                 send_del_subnet(everyone, subnet);
 287                                 if(subnet->owner->status.reachable)
 288                                         subnet_update(subnet->owner, subnet, false);
 289                                 subnet_del(subnet->owner, subnet);
 290                         } else if(subnet->expires == -1) {
 291                                 subnet->expires = 0;
 292                         } else {
 293                                 send_add_subnet(everyone, subnet);
 294                                 if(subnet->owner->status.reachable)
 295                                         subnet_update(subnet->owner, subnet, true);
 296                         }
 297                 }
 298         } else { /* Only read our own subnets back in */
 299                 for(splay_node_t *node = myself->subnet_tree->head; node; node = node->next) {
 300                         subnet_t *subnet = node->data;
 301                         if(!subnet->expires)
 302                                 subnet->expires = 1;
 303                 }
 304
 305                 config_t *cfg = lookup_config(config_tree, "Subnet");
 306
 307                 while(cfg) {
 308                         subnet_t *subnet, *s2;
 309
 310                         if(!get_config_subnet(cfg, &subnet))
 311                                 continue;
 312
 313                         if((s2 = lookup_subnet(myself, subnet))) {
 314                                 if(s2->expires == 1)
 315                                         s2->expires = 0;
 316
 317                                 free_subnet(subnet);
 318                         } else {
 319                                 subnet_add(myself, subnet);
 320                                 send_add_subnet(everyone, subnet);
 321                                 subnet_update(myself, subnet, true);
 322                         }
 323
 324                         cfg = lookup_config_next(config_tree, cfg);
 325                 }
 326
 327                 for(splay_node_t *node = myself->subnet_tree->head, *next; node; node = next) {
 328                         next = node->next;
 329                         subnet_t *subnet = node->data;
 330                         if(subnet->expires == 1) {
 331                                 send_del_subnet(everyone, subnet);
 332                                 subnet_update(myself, subnet, false);
 333                                 subnet_del(myself, subnet);
 334                         }
 335                 }
 336         }
 337
 338         /* Try to make outgoing connections */
 339
 340         try_outgoing_connections();
 341
 342         /* Close connections to hosts that have a changed or deleted host config file */
 343
 344         for(list_node_t *node = connection_list->head, *next; node; node = next) {
 345                 connection_t *c = node->data;
 346                 next = node->next;
 347
 348                 if(c->status.control)
 349                         continue;
 350
 351                 xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
 352                 struct stat s;
 353                 if(stat(fname, &s) || s.st_mtime > last_config_check) {
 354                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Host config file of %s has been changed", c->name);
 355                         terminate_connection(c, c->status.active);
 356                 }
 357                 free(fname);
 358         }
 359
 360         last_config_check = time(NULL);
 361
 362         return 0;
 363 }
 364
 365 void retry(void) {
 366         for(list_node_t *node = connection_list->head, *next; node; node = next) {
 367                 next = node->next;
 368                 connection_t *c = node->data;
 369
 370                 if(c->outgoing && !c->node) {
 371                         if(timeout_initialized(&c->outgoing->ev))
 372                                 event_del(&c->outgoing->ev);
 373                         if(c->status.connecting)
 374                                 close(c->socket);
 375                         c->outgoing->timeout = 0;
 376                         terminate_connection(c, c->status.active);
 377                 }
 378         }
 379 }
 380
 381 /*
 382   this is where it all happens...
 383 */
 384 int main_loop(void) {
 385         struct event timeout_event;
 386
 387         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 388         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 389
 390 #ifndef HAVE_MINGW
 391         struct event sighup_event;
 392         struct event sigterm_event;
 393         struct event sigquit_event;
 394         struct event sigalrm_event;
 395
 396         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 397         signal_add(&sighup_event, NULL);
 398         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 399         signal_add(&sigterm_event, NULL);
 400         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 401         signal_add(&sigquit_event, NULL);
 402         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 403         signal_add(&sigalrm_event, NULL);
 404 #endif
 405
 406         if(event_loop(0) < 0) {
 407                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 408                 return 1;
 409         }
 410
 411 #ifndef HAVE_MINGW
 412         signal_del(&sighup_event);
 413         signal_del(&sigterm_event);
 414         signal_del(&sigquit_event);
 415         signal_del(&sigalrm_event);
 416 #endif
 417
 418         event_del(&timeout_event);
 419
 420         return 0;
 421 }