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 "splay_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 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  43
  44 static void purge(void) {
  45         splay_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
  46         node_t *n;
  47         edge_t *e;
  48         subnet_t *s;
  49
  50         cp();
  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                                 if(!tunnelserver)
  68                                         send_del_subnet(broadcast, s);
  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(broadcast, 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)
  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         cp();
 112
 113         ifdebug(CONNECTIONS) logger(LOG_NOTICE, _("Closing connection with %s (%s)"),
 114                            c->name, c->hostname);
 115
 116         c->status.active = false;
 117
 118         if(c->node)
 119                 c->node->connection = NULL;
 120
 121         if(c->socket)
 122                 closesocket(c->socket);
 123
 124         event_del(&c->ev);
 125
 126         if(c->edge) {
 127                 if(report && !tunnelserver)
 128                         send_del_edge(broadcast, c->edge);
 129
 130                 edge_del(c->edge);
 131
 132                 /* Run MST and SSSP algorithms */
 133
 134                 graph();
 135
 136                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 137
 138                 if(report && !c->node->status.reachable) {
 139                         edge_t *e;
 140                         e = lookup_edge(c->node, myself);
 141                         if(e) {
 142                                 if(!tunnelserver)
 143                                         send_del_edge(broadcast, e);
 144                                 edge_del(e);
 145                         }
 146                 }
 147         }
 148
 149         free(c->outbuf);
 150         c->outbuf = NULL;
 151         c->outbuflen = 0;
 152         c->outbufsize = 0;
 153         c->outbufstart = 0;
 154
 155         /* Check if this was our outgoing connection */
 156
 157         if(c->outgoing)
 158                 retry_outgoing(c->outgoing);
 159
 160         connection_del(c);
 161 }
 162
 163 /*
 164   Check if the other end is active.
 165   If we have sent packets, but didn't receive any,
 166   then possibly the other end is dead. We send a
 167   PING request over the meta connection. If the other
 168   end does not reply in time, we consider them dead
 169   and close the connection.
 170 */
 171 static void timeout_handler(int fd, short events, void *event) {
 172         splay_node_t *node, *next;
 173         connection_t *c;
 174         time_t now = time(NULL);
 175
 176         cp();
 177
 178         for(node = connection_tree->head; node; node = next) {
 179                 next = node->next;
 180                 c = node->data;
 181
 182                 if(c->last_ping_time + pingtimeout < now) {
 183                         if(c->status.active) {
 184                                 if(c->status.pinged) {
 185                                         ifdebug(CONNECTIONS) logger(LOG_INFO, _("%s (%s) didn't respond to PING in %ld seconds"),
 186                                                            c->name, c->hostname, now - c->last_ping_time);
 187                                         terminate_connection(c, true);
 188                                         continue;
 189                                 } else if(c->last_ping_time + pinginterval < now) {
 190                                         send_ping(c);
 191                                 }
 192                         } else {
 193                                 if(c->status.connecting) {
 194                                         ifdebug(CONNECTIONS)
 195                                                 logger(LOG_WARNING, _("Timeout while connecting to %s (%s)"), c->name, c->hostname);
 196                                         c->status.connecting = false;
 197                                         closesocket(c->socket);
 198                                         do_outgoing_connection(c);
 199                                 } else {
 200                                         ifdebug(CONNECTIONS) logger(LOG_WARNING, _("Timeout from %s (%s) during authentication"), c->name, c->hostname);
 201                                         terminate_connection(c, false);
 202                                         continue;
 203                                 }
 204                         }
 205                 }
 206         }
 207
 208         event_add(event, &(struct timeval){pingtimeout, 0});
 209 }
 210
 211 void handle_meta_connection_data(int fd, short events, void *data) {
 212         connection_t *c = data;
 213         int result;
 214         socklen_t len = sizeof(result);
 215
 216         if(c->status.connecting) {
 217                 c->status.connecting = false;
 218
 219                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 220
 221                 if(!result)
 222                         finish_connecting(c);
 223                 else {
 224                         ifdebug(CONNECTIONS) logger(LOG_DEBUG,
 225                                            _("Error while connecting to %s (%s): %s"),
 226                                            c->name, c->hostname, strerror(result));
 227                         closesocket(c->socket);
 228                         do_outgoing_connection(c);
 229                         return;
 230                 }
 231         }
 232
 233         if (!receive_meta(c)) {
 234                 terminate_connection(c, c->status.active);
 235                 return;
 236         }
 237 }
 238
 239 static void sigterm_handler(int signal, short events, void *data) {
 240         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 241         event_loopexit(NULL);
 242 }
 243
 244 static void sigint_handler(int signal, short events, void *data) {
 245         static int saved_debug_level = -1;
 246
 247         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 248
 249         if(saved_debug_level != -1) {
 250                 logger(LOG_NOTICE, _("Reverting to old debug level (%d)"),
 251                         saved_debug_level);
 252                 debug_level = saved_debug_level;
 253                 saved_debug_level = -1;
 254         } else {
 255                 logger(LOG_NOTICE,
 256                         _("Temporarily setting debug level to 5.  Kill me with SIGINT again to go back to level %d."),
 257                         debug_level);
 258                 saved_debug_level = debug_level;
 259                 debug_level = 5;
 260         }
 261 }
 262
 263 static void sigusr1_handler(int signal, short events, void *data) {
 264         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 265         dump_connections();
 266 }
 267
 268 static void sigusr2_handler(int signal, short events, void *data) {
 269         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 270         dump_device_stats();
 271         dump_nodes();
 272         dump_edges();
 273         dump_subnets();
 274 }
 275
 276 static void sigwinch_handler(int signal, short events, void *data) {
 277         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 278         purge();
 279 }
 280
 281 static void sighup_handler(int signal, short events, void *data) {
 282         connection_t *c;
 283         splay_node_t *node;
 284         char *fname;
 285         struct stat s;
 286         static time_t last_config_check = 0;
 287
 288         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 289
 290         /* Reread our own configuration file */
 291
 292         exit_configuration(&config_tree);
 293         init_configuration(&config_tree);
 294
 295         if(!read_server_config()) {
 296                 logger(LOG_ERR, _("Unable to reread configuration file, exitting."));
 297                 event_loopexit(NULL);
 298                 return;
 299         }
 300
 301         /* Close connections to hosts that have a changed or deleted host config file */
 302
 303         for(node = connection_tree->head; node; node = node->next) {
 304                 c = node->data;
 305
 306                 if(c->outgoing) {
 307                         free(c->outgoing->name);
 308                         if(c->outgoing->ai)
 309                                 freeaddrinfo(c->outgoing->ai);
 310                         free(c->outgoing);
 311                         c->outgoing = NULL;
 312                 }
 313
 314                 asprintf(&fname, "%s/hosts/%s", confbase, c->name);
 315                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 316                         terminate_connection(c, c->status.active);
 317                 free(fname);
 318         }
 319
 320         last_config_check = time(NULL);
 321
 322         /* Try to make outgoing connections */
 323
 324         try_outgoing_connections();
 325 }
 326
 327 static void sigalrm_handler(int signal, short events, void *data) {
 328         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 329
 330         connection_t *c;
 331         splay_node_t *node;
 332
 333         for(node = connection_tree->head; node; node = node->next) {
 334                 c = node->data;
 335
 336                 if(c->outgoing && !c->node) {
 337                         if(timeout_initialized(&c->outgoing->ev))
 338                                 event_del(&c->outgoing->ev);
 339                         if(c->status.connecting)
 340                                 close(c->socket);
 341                         c->outgoing->timeout = 0;
 342                         do_outgoing_connection(c);
 343                 }
 344         }
 345 }
 346
 347 /*
 348   this is where it all happens...
 349 */
 350 int main_loop(void) {
 351         struct event timeout_event;
 352         struct event sighup_event;
 353         struct event sigint_event;
 354         struct event sigterm_event;
 355         struct event sigquit_event;
 356         struct event sigusr1_event;
 357         struct event sigusr2_event;
 358         struct event sigwinch_event;
 359         struct event sigalrm_event;
 360
 361         cp();
 362
 363         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 364         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 365         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 366         signal_add(&sighup_event, NULL);
 367         signal_set(&sigint_event, SIGINT, sigint_handler, NULL);
 368         signal_add(&sigint_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(&sigusr1_event, SIGUSR1, sigusr1_handler, NULL);
 374         signal_add(&sigusr1_event, NULL);
 375         signal_set(&sigusr2_event, SIGUSR2, sigusr2_handler, NULL);
 376         signal_add(&sigusr2_event, NULL);
 377         signal_set(&sigwinch_event, SIGWINCH, sigwinch_handler, NULL);
 378         signal_add(&sigwinch_event, NULL);
 379         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 380         signal_add(&sigalrm_event, NULL);
 381
 382         if(event_loop(0) < 0) {
 383                 logger(LOG_ERR, _("Error while waiting for input: %s"), strerror(errno));
 384                 return 1;
 385         }
 386
 387         signal_del(&sighup_event);
 388         signal_del(&sigint_event);
 389         signal_del(&sigterm_event);
 390         signal_del(&sigquit_event);
 391         signal_del(&sigusr1_event);
 392         signal_del(&sigusr2_event);
 393         signal_del(&sigwinch_event);
 394         signal_del(&sigalrm_event);
 395         event_del(&timeout_event);
 396
 397         return 0;
 398 }