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                 c->outgoing = NULL;
 160         } else {
 161                 connection_del(c);
 162         }
 163 }
 164
 165 /*
 166   Check if the other end is active.
 167   If we have sent packets, but didn't receive any,
 168   then possibly the other end is dead. We send a
 169   PING request over the meta connection. If the other
 170   end does not reply in time, we consider them dead
 171   and close the connection.
 172 */
 173 static void timeout_handler(int fd, short events, void *event) {
 174         splay_node_t *node, *next;
 175         connection_t *c;
 176         time_t now = time(NULL);
 177
 178         cp();
 179
 180         for(node = connection_tree->head; node; node = next) {
 181                 next = node->next;
 182                 c = node->data;
 183
 184                 if(c->last_ping_time + pingtimeout < now) {
 185                         if(c->status.active) {
 186                                 if(c->status.pinged) {
 187                                         ifdebug(CONNECTIONS) logger(LOG_INFO, _("%s (%s) didn't respond to PING in %ld seconds"),
 188                                                            c->name, c->hostname, now - c->last_ping_time);
 189                                         c->status.timeout = true;
 190                                         terminate_connection(c, true);
 191                                         continue;
 192                                 } else if(c->last_ping_time + pinginterval < now) {
 193                                         send_ping(c);
 194                                 }
 195                         } else {
 196                                 ifdebug(CONNECTIONS) logger(LOG_WARNING, _("Timeout from %s (%s) during authentication"),
 197                                                    c->name, c->hostname);
 198                                 if(c->status.connecting) {
 199                                         c->status.connecting = false;
 200                                         closesocket(c->socket);
 201                                         do_outgoing_connection(c);
 202                                 } else {
 203                                         terminate_connection(c, false);
 204                                         continue;
 205                                 }
 206                         }
 207                 }
 208         }
 209
 210         event_add(event, &(struct timeval){pingtimeout, 0});
 211 }
 212
 213 void handle_meta_connection_data(int fd, short events, void *data) {
 214         connection_t *c = data;
 215         int result;
 216         socklen_t len = sizeof(result);
 217
 218         if(c->status.connecting) {
 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                         c->status.connecting = false;
 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 sigint_handler(int signal, short events, void *data) {
 246         static int saved_debug_level = -1;
 247
 248         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 249
 250         if(saved_debug_level != -1) {
 251                 logger(LOG_NOTICE, _("Reverting to old debug level (%d)"),
 252                         saved_debug_level);
 253                 debug_level = saved_debug_level;
 254                 saved_debug_level = -1;
 255         } else {
 256                 logger(LOG_NOTICE,
 257                         _("Temporarily setting debug level to 5.  Kill me with SIGINT again to go back to level %d."),
 258                         debug_level);
 259                 saved_debug_level = debug_level;
 260                 debug_level = 5;
 261         }
 262 }
 263
 264 static void sigusr1_handler(int signal, short events, void *data) {
 265         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 266         dump_connections();
 267 }
 268
 269 static void sigusr2_handler(int signal, short events, void *data) {
 270         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 271         dump_device_stats();
 272         dump_nodes();
 273         dump_edges();
 274         dump_subnets();
 275 }
 276
 277 static void sigwinch_handler(int signal, short events, void *data) {
 278         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 279         purge();
 280 }
 281
 282 static void sighup_handler(int signal, short events, void *data) {
 283         connection_t *c;
 284         splay_node_t *node;
 285         char *fname;
 286         struct stat s;
 287         static time_t last_config_check = 0;
 288
 289         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 290
 291         /* Reread our own configuration file */
 292
 293         exit_configuration(&config_tree);
 294         init_configuration(&config_tree);
 295
 296         if(!read_server_config()) {
 297                 logger(LOG_ERR, _("Unable to reread configuration file, exitting."));
 298                 event_loopexit(NULL);
 299                 return;
 300         }
 301
 302         /* Close connections to hosts that have a changed or deleted host config file */
 303
 304         for(node = connection_tree->head; node; node = node->next) {
 305                 c = node->data;
 306
 307                 if(c->outgoing) {
 308                         free(c->outgoing->name);
 309                         if(c->outgoing->ai)
 310                                 freeaddrinfo(c->outgoing->ai);
 311                         free(c->outgoing);
 312                         c->outgoing = NULL;
 313                 }
 314
 315                 asprintf(&fname, "%s/hosts/%s", confbase, c->name);
 316                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 317                         terminate_connection(c, c->status.active);
 318                 free(fname);
 319         }
 320
 321         last_config_check = time(NULL);
 322
 323         /* Try to make outgoing connections */
 324
 325         try_outgoing_connections();
 326 }
 327
 328 static void sigalrm_handler(int signal, short events, void *data) {
 329         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 330
 331         connection_t *c;
 332         splay_node_t *node;
 333
 334         for(node = connection_tree->head; node; node = node->next) {
 335                 c = node->data;
 336
 337                 if(c->outgoing && !c->node) {
 338                         if(timeout_initialized(&c->outgoing->ev))
 339                                 event_del(&c->outgoing->ev);
 340                         if(c->status.connecting)
 341                                 close(c->socket);
 342                         c->outgoing->timeout = 0;
 343                         do_outgoing_connection(c);
 344                 }
 345         }
 346 }
 347
 348 /*
 349   this is where it all happens...
 350 */
 351 int main_loop(void) {
 352         struct event timeout_event;
 353         struct event sighup_event;
 354         struct event sigint_event;
 355         struct event sigterm_event;
 356         struct event sigquit_event;
 357         struct event sigusr1_event;
 358         struct event sigusr2_event;
 359         struct event sigwinch_event;
 360         struct event sigalrm_event;
 361
 362         cp();
 363
 364         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 365         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 366         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 367         signal_add(&sighup_event, NULL);
 368         signal_set(&sigint_event, SIGINT, sigint_handler, NULL);
 369         signal_add(&sigint_event, NULL);
 370         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 371         signal_add(&sigterm_event, NULL);
 372         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 373         signal_add(&sigquit_event, NULL);
 374         signal_set(&sigusr1_event, SIGUSR1, sigusr1_handler, NULL);
 375         signal_add(&sigusr1_event, NULL);
 376         signal_set(&sigusr2_event, SIGUSR2, sigusr2_handler, NULL);
 377         signal_add(&sigusr2_event, NULL);
 378         signal_set(&sigwinch_event, SIGWINCH, sigwinch_handler, NULL);
 379         signal_add(&sigwinch_event, NULL);
 380         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 381         signal_add(&sigalrm_event, NULL);
 382
 383         if(event_loop(0) < 0) {
 384                 logger(LOG_ERR, _("Error while waiting for input: %s"), strerror(errno));
 385                 return 1;
 386         }
 387
 388         signal_del(&sighup_event);
 389         signal_del(&sigint_event);
 390         signal_del(&sigterm_event);
 391         signal_del(&sigquit_event);
 392         signal_del(&sigusr1_event);
 393         signal_del(&sigusr2_event);
 394         signal_del(&sigwinch_event);
 395         signal_del(&sigalrm_event);
 396         event_del(&timeout_event);
 397
 398         return 0;
 399 }