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                   2000-2011 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         ifdebug(PROTOCOL) logger(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                         ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Purging node %s (%s)", n->name,
  62                                            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   - Close the socket
 107   - Remove associated edge and tell other connections about it if report = true
 108   - Check if we need to retry making an outgoing connection
 109   - Deactivate the host
 110 */
 111 void terminate_connection(connection_t *c, bool report) {
 112         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Closing connection with %s (%s)",
 113                            c->name, c->hostname);
 114
 115         c->status.active = false;
 116
 117         if(c->node)
 118                 c->node->connection = NULL;
 119
 120         if(c->edge) {
 121                 if(report && !tunnelserver)
 122                         send_del_edge(everyone, c->edge);
 123
 124                 edge_del(c->edge);
 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         /* Check if this was our outgoing connection */
 144
 145         if(c->outgoing)
 146                 retry_outgoing(c->outgoing);
 147
 148         connection_del(c);
 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         splay_node_t *node, *next;
 161         connection_t *c;
 162         time_t now = time(NULL);
 163
 164         for(node = connection_tree->head; node; node = next) {
 165                 next = node->next;
 166                 c = node->data;
 167
 168                 if(c->last_ping_time + pingtimeout <= now) {
 169                         if(c->status.active) {
 170                                 if(c->status.pinged) {
 171                                         ifdebug(CONNECTIONS) logger(LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
 172                                                            c->name, c->hostname, now - c->last_ping_time);
 173                                         terminate_connection(c, true);
 174                                         continue;
 175                                 } else if(c->last_ping_time + pinginterval <= now) {
 176                                         send_ping(c);
 177                                 }
 178                         } else {
 179                                 if(c->status.connecting) {
 180                                         ifdebug(CONNECTIONS)
 181                                                 logger(LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 182                                         c->status.connecting = false;
 183                                         closesocket(c->socket);
 184                                         do_outgoing_connection(c);
 185                                 } else {
 186                                         ifdebug(CONNECTIONS) logger(LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 187                                         terminate_connection(c, false);
 188                                         continue;
 189                                 }
 190                         }
 191                 }
 192         }
 193
 194         if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
 195                 logger(LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
 196                 usleep(sleeptime * 1000000LL);
 197                 sleeptime *= 2;
 198                 if(sleeptime < 0)
 199                         sleeptime = 3600;
 200         } else {
 201                 sleeptime /= 2;
 202                 if(sleeptime < 10)
 203                         sleeptime = 10;
 204         }
 205
 206         contradicting_add_edge = 0;
 207         contradicting_del_edge = 0;
 208
 209         event_add(event, &(struct timeval){pingtimeout, 0});
 210 }
 211
 212 void handle_meta_connection_data(int fd, short events, void *data) {
 213         connection_t *c = data;
 214         int result;
 215         socklen_t len = sizeof result;
 216
 217         if(c->status.connecting) {
 218                 c->status.connecting = false;
 219
 220                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 221
 222                 if(!result)
 223                         finish_connecting(c);
 224                 else {
 225                         ifdebug(CONNECTIONS) logger(LOG_DEBUG,
 226                                            "Error while connecting to %s (%s): %s",
 227                                            c->name, c->hostname, sockstrerror(result));
 228                         closesocket(c->socket);
 229                         do_outgoing_connection(c);
 230                         return;
 231                 }
 232         }
 233
 234         if (!receive_meta(c)) {
 235                 terminate_connection(c, c->status.active);
 236                 return;
 237         }
 238 }
 239
 240 static void sigterm_handler(int signal, short events, void *data) {
 241         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 242         event_loopexit(NULL);
 243 }
 244
 245 static void sighup_handler(int signal, short events, void *data) {
 246         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 247         reopenlogger();
 248         reload_configuration();
 249 }
 250
 251 static void sigalrm_handler(int signal, short events, void *data) {
 252         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 253         retry();
 254 }
 255
 256 int reload_configuration(void) {
 257         connection_t *c;
 258         splay_node_t *node, *next;
 259         char *fname;
 260         struct stat s;
 261         static time_t last_config_check = 0;
 262
 263         /* Reread our own configuration file */
 264
 265         exit_configuration(&config_tree);
 266         init_configuration(&config_tree);
 267
 268         if(!read_server_config()) {
 269                 logger(LOG_ERR, "Unable to reread configuration file, exitting.");
 270                 event_loopexit(NULL);
 271                 return EINVAL;
 272         }
 273
 274         /* Close connections to hosts that have a changed or deleted host config file */
 275
 276         for(node = connection_tree->head; node; node = next) {
 277                 c = node->data;
 278                 next = node->next;
 279
 280                 if(c->outgoing) {
 281                         free(c->outgoing->name);
 282                         if(c->outgoing->ai)
 283                                 freeaddrinfo(c->outgoing->ai);
 284                         free(c->outgoing);
 285                         c->outgoing = NULL;
 286                 }
 287
 288                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 289                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 290                         terminate_connection(c, c->status.active);
 291                 free(fname);
 292         }
 293
 294         last_config_check = time(NULL);
 295
 296         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 297
 298         if(strictsubnets) {
 299                 subnet_t *subnet;
 300
 301
 302                 for(node = subnet_tree->head; node; node = node->next) {
 303                         subnet = node->data;
 304                         subnet->expires = 1;
 305                 }
 306
 307                 load_all_subnets();
 308
 309                 for(node = subnet_tree->head; node; node = next) {
 310                         next = node->next;
 311                         subnet = node->data;
 312                         if(subnet->expires == 1) {
 313                                 send_del_subnet(everyone, subnet);
 314                                 if(subnet->owner->status.reachable)
 315                                         subnet_update(subnet->owner, subnet, false);
 316                                 subnet_del(subnet->owner, subnet);
 317                         } else if(subnet->expires == -1) {
 318                                 subnet->expires = 0;
 319                         } else {
 320                                 send_add_subnet(everyone, subnet);
 321                                 if(subnet->owner->status.reachable)
 322                                         subnet_update(subnet->owner, subnet, true);
 323                         }
 324                 }
 325         }
 326
 327         /* Try to make outgoing connections */
 328
 329         try_outgoing_connections();
 330
 331         return 0;
 332 }
 333
 334 void retry(void) {
 335         connection_t *c;
 336         splay_node_t *node;
 337
 338         for(node = connection_tree->head; node; node = node->next) {
 339                 c = node->data;
 340
 341                 if(c->outgoing && !c->node) {
 342                         if(timeout_initialized(&c->outgoing->ev))
 343                                 event_del(&c->outgoing->ev);
 344                         if(c->status.connecting)
 345                                 close(c->socket);
 346                         c->outgoing->timeout = 0;
 347                         do_outgoing_connection(c);
 348                 }
 349         }
 350 }
 351
 352 /*
 353   this is where it all happens...
 354 */
 355 int main_loop(void) {
 356         struct event timeout_event;
 357
 358         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 359         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 360
 361 #ifndef HAVE_MINGW
 362         struct event sighup_event;
 363         struct event sigterm_event;
 364         struct event sigquit_event;
 365         struct event sigalrm_event;
 366
 367         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 368         signal_add(&sighup_event, NULL);
 369         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 370         signal_add(&sigterm_event, NULL);
 371         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 372         signal_add(&sigquit_event, NULL);
 373         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 374         signal_add(&sigalrm_event, NULL);
 375 #endif
 376
 377         if(event_loop(0) < 0) {
 378                 logger(LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 379                 return 1;
 380         }
 381
 382 #ifndef HAVE_MINGW
 383         signal_del(&sighup_event);
 384         signal_del(&sigterm_event);
 385         signal_del(&sigquit_event);
 386         signal_del(&sigalrm_event);
 387 #endif
 388
 389         event_del(&timeout_event);
 390
 391         return 0;
 392 }