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
  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   - Close the socket
 106   - Remove associated edge and tell other connections about it if report = true
 107   - Check if we need to retry making an outgoing connection
 108   - Deactivate the host
 109 */
 110 void terminate_connection(connection_t *c, bool report) {
 111         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)",
 112                            c->name, c->hostname);
 113
 114         c->status.active = false;
 115
 116         if(c->node)
 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         free_connection_partially(c);
 144
 145         /* Check if this was our outgoing connection */
 146
 147         if(c->outgoing) {
 148                 do_outgoing_connection(c);
 149         }
 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",
 176                                                            c->name, c->hostname, (long)now - c->last_ping_time);
 177                                         terminate_connection(c, true);
 178                                         continue;
 179                                 } else if(c->last_ping_time + pinginterval <= now) {
 180                                         send_ping(c);
 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                                         c->status.connecting = false;
 186                                         closesocket(c->socket);
 187                                         do_outgoing_connection(c);
 188                                 } else {
 189                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 190                                         terminate_connection(c, false);
 191                                         continue;
 192                                 }
 193                         }
 194                 }
 195         }
 196
 197         if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
 198                 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
 199                 usleep(sleeptime * 1000000LL);
 200                 sleeptime *= 2;
 201                 if(sleeptime < 0)
 202                         sleeptime = 3600;
 203         } else {
 204                 sleeptime /= 2;
 205                 if(sleeptime < 10)
 206                         sleeptime = 10;
 207         }
 208
 209         contradicting_add_edge = 0;
 210         contradicting_del_edge = 0;
 211
 212         event_add(event, &(struct timeval){pingtimeout, 0});
 213 }
 214
 215 void handle_meta_connection_data(int fd, short events, void *data) {
 216         connection_t *c = data;
 217         int result;
 218         socklen_t len = sizeof result;
 219
 220         if(c->status.connecting) {
 221                 c->status.connecting = false;
 222
 223                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 224
 225                 if(!result)
 226                         finish_connecting(c);
 227                 else {
 228                         logger(DEBUG_CONNECTIONS, LOG_DEBUG,
 229                                            "Error while connecting to %s (%s): %s",
 230                                            c->name, c->hostname, sockstrerror(result));
 231                         closesocket(c->socket);
 232                         do_outgoing_connection(c);
 233                         return;
 234                 }
 235         }
 236
 237         if (!receive_meta(c)) {
 238                 terminate_connection(c, c->status.active);
 239                 return;
 240         }
 241 }
 242
 243 static void sigterm_handler(int signal, short events, void *data) {
 244         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 245         event_loopexit(NULL);
 246 }
 247
 248 static void sighup_handler(int signal, short events, void *data) {
 249         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 250         reopenlogger();
 251         reload_configuration();
 252 }
 253
 254 static void sigalrm_handler(int signal, short events, void *data) {
 255         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 256         retry();
 257 }
 258
 259 int reload_configuration(void) {
 260         connection_t *c;
 261         splay_node_t *node, *next;
 262         char *fname;
 263         struct stat s;
 264         static time_t last_config_check = 0;
 265
 266         /* Reread our own configuration file */
 267
 268         exit_configuration(&config_tree);
 269         init_configuration(&config_tree);
 270
 271         if(!read_server_config()) {
 272                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file, exitting.");
 273                 event_loopexit(NULL);
 274                 return EINVAL;
 275         }
 276
 277         /* Close connections to hosts that have a changed or deleted host config file */
 278
 279         for(node = connection_tree->head; node; node = next) {
 280                 c = node->data;
 281                 next = node->next;
 282
 283                 if(c->status.control)
 284                         continue;
 285
 286                 if(c->outgoing) {
 287                         free(c->outgoing->name);
 288                         if(c->outgoing->ai)
 289                                 freeaddrinfo(c->outgoing->ai);
 290                         free(c->outgoing);
 291                         c->outgoing = NULL;
 292                 }
 293
 294                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 295                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 296                         terminate_connection(c, c->status.active);
 297                 free(fname);
 298         }
 299
 300         last_config_check = time(NULL);
 301
 302         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 303
 304         if(strictsubnets) {
 305                 subnet_t *subnet;
 306
 307
 308                 for(node = subnet_tree->head; node; node = node->next) {
 309                         subnet = node->data;
 310                         subnet->expires = 1;
 311                 }
 312
 313                 load_all_subnets();
 314
 315                 for(node = subnet_tree->head; node; node = next) {
 316                         next = node->next;
 317                         subnet = node->data;
 318                         if(subnet->expires == 1) {
 319                                 send_del_subnet(everyone, subnet);
 320                                 if(subnet->owner->status.reachable)
 321                                         subnet_update(subnet->owner, subnet, false);
 322                                 subnet_del(subnet->owner, subnet);
 323                         } else if(subnet->expires == -1) {
 324                                 subnet->expires = 0;
 325                         } else {
 326                                 send_add_subnet(everyone, subnet);
 327                                 if(subnet->owner->status.reachable)
 328                                         subnet_update(subnet->owner, subnet, true);
 329                         }
 330                 }
 331         }
 332
 333         /* Try to make outgoing connections */
 334
 335         try_outgoing_connections();
 336
 337         return 0;
 338 }
 339
 340 void retry(void) {
 341         connection_t *c;
 342         splay_node_t *node;
 343
 344         for(node = connection_tree->head; node; node = node->next) {
 345                 c = node->data;
 346
 347                 if(c->outgoing && !c->node) {
 348                         if(timeout_initialized(&c->outgoing->ev))
 349                                 event_del(&c->outgoing->ev);
 350                         if(c->status.connecting)
 351                                 close(c->socket);
 352                         c->outgoing->timeout = 0;
 353                         do_outgoing_connection(c);
 354                 }
 355         }
 356 }
 357
 358 /*
 359   this is where it all happens...
 360 */
 361 int main_loop(void) {
 362         struct event timeout_event;
 363
 364         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 365         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 366
 367 #ifndef HAVE_MINGW
 368         struct event sighup_event;
 369         struct event sigterm_event;
 370         struct event sigquit_event;
 371         struct event sigalrm_event;
 372
 373         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 374         signal_add(&sighup_event, NULL);
 375         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 376         signal_add(&sigterm_event, NULL);
 377         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 378         signal_add(&sigquit_event, NULL);
 379         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 380         signal_add(&sigalrm_event, NULL);
 381 #endif
 382
 383         if(event_loop(0) < 0) {
 384                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 385                 return 1;
 386         }
 387
 388 #ifndef HAVE_MINGW
 389         signal_del(&sighup_event);
 390         signal_del(&sigterm_event);
 391         signal_del(&sigquit_event);
 392         signal_del(&sigalrm_event);
 393 #endif
 394
 395         event_del(&timeout_event);
 396
 397         return 0;
 398 }