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         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
 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         /* Check if this was our outgoing connection */
 143
 144         if(c->outgoing)
 145                 retry_outgoing(c->outgoing);
 146
 147         connection_del(c);
 148 }
 149
 150 /*
 151   Check if the other end is active.
 152   If we have sent packets, but didn't receive any,
 153   then possibly the other end is dead. We send a
 154   PING request over the meta connection. If the other
 155   end does not reply in time, we consider them dead
 156   and close the connection.
 157 */
 158 static void timeout_handler(int fd, short events, void *event) {
 159         splay_node_t *node, *next;
 160         connection_t *c;
 161         time_t now = time(NULL);
 162
 163         for(node = connection_tree->head; node; node = next) {
 164                 next = node->next;
 165                 c = node->data;
 166
 167                 if(c->status.control)
 168                         continue;
 169
 170                 if(c->last_ping_time + pingtimeout <= now) {
 171                         if(c->status.active) {
 172                                 if(c->status.pinged) {
 173                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
 174                                                            c->name, c->hostname, now - c->last_ping_time);
 175                                         terminate_connection(c, true);
 176                                         continue;
 177                                 } else if(c->last_ping_time + pinginterval <= now) {
 178                                         send_ping(c);
 179                                 }
 180                         } else {
 181                                 if(c->status.connecting) {
 182                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 183                                         c->status.connecting = false;
 184                                         closesocket(c->socket);
 185                                         do_outgoing_connection(c);
 186                                 } else {
 187                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 188                                         terminate_connection(c, false);
 189                                         continue;
 190                                 }
 191                         }
 192                 }
 193         }
 194
 195         if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
 196                 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
 197                 usleep(sleeptime * 1000000LL);
 198                 sleeptime *= 2;
 199                 if(sleeptime < 0)
 200                         sleeptime = 3600;
 201         } else {
 202                 sleeptime /= 2;
 203                 if(sleeptime < 10)
 204                         sleeptime = 10;
 205         }
 206
 207         contradicting_add_edge = 0;
 208         contradicting_del_edge = 0;
 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                 c->status.connecting = false;
 220
 221                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 222
 223                 if(!result)
 224                         finish_connecting(c);
 225                 else {
 226                         logger(DEBUG_CONNECTIONS, LOG_DEBUG,
 227                                            "Error while connecting to %s (%s): %s",
 228                                            c->name, c->hostname, sockstrerror(result));
 229                         closesocket(c->socket);
 230                         do_outgoing_connection(c);
 231                         return;
 232                 }
 233         }
 234
 235         if (!receive_meta(c)) {
 236                 terminate_connection(c, c->status.active);
 237                 return;
 238         }
 239 }
 240
 241 static void sigterm_handler(int signal, short events, void *data) {
 242         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 243         event_loopexit(NULL);
 244 }
 245
 246 static void sighup_handler(int signal, short events, void *data) {
 247         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 248         reopenlogger();
 249         reload_configuration();
 250 }
 251
 252 static void sigalrm_handler(int signal, short events, void *data) {
 253         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 254         retry();
 255 }
 256
 257 int reload_configuration(void) {
 258         connection_t *c;
 259         splay_node_t *node, *next;
 260         char *fname;
 261         struct stat s;
 262         static time_t last_config_check = 0;
 263
 264         /* Reread our own configuration file */
 265
 266         exit_configuration(&config_tree);
 267         init_configuration(&config_tree);
 268
 269         if(!read_server_config()) {
 270                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file, exitting.");
 271                 event_loopexit(NULL);
 272                 return EINVAL;
 273         }
 274
 275         /* Close connections to hosts that have a changed or deleted host config file */
 276
 277         for(node = connection_tree->head; node; node = next) {
 278                 c = node->data;
 279                 next = node->next;
 280
 281                 if(c->status.control)
 282                         continue;
 283
 284                 if(c->outgoing) {
 285                         free(c->outgoing->name);
 286                         if(c->outgoing->ai)
 287                                 freeaddrinfo(c->outgoing->ai);
 288                         free(c->outgoing);
 289                         c->outgoing = NULL;
 290                 }
 291
 292                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 293                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 294                         terminate_connection(c, c->status.active);
 295                 free(fname);
 296         }
 297
 298         last_config_check = time(NULL);
 299
 300         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 301
 302         if(strictsubnets) {
 303                 subnet_t *subnet;
 304
 305
 306                 for(node = subnet_tree->head; node; node = node->next) {
 307                         subnet = node->data;
 308                         subnet->expires = 1;
 309                 }
 310
 311                 load_all_subnets();
 312
 313                 for(node = subnet_tree->head; node; node = next) {
 314                         next = node->next;
 315                         subnet = node->data;
 316                         if(subnet->expires == 1) {
 317                                 send_del_subnet(everyone, subnet);
 318                                 if(subnet->owner->status.reachable)
 319                                         subnet_update(subnet->owner, subnet, false);
 320                                 subnet_del(subnet->owner, subnet);
 321                         } else if(subnet->expires == -1) {
 322                                 subnet->expires = 0;
 323                         } else {
 324                                 send_add_subnet(everyone, subnet);
 325                                 if(subnet->owner->status.reachable)
 326                                         subnet_update(subnet->owner, subnet, true);
 327                         }
 328                 }
 329         }
 330
 331         /* Try to make outgoing connections */
 332
 333         try_outgoing_connections();
 334
 335         return 0;
 336 }
 337
 338 void retry(void) {
 339         connection_t *c;
 340         splay_node_t *node;
 341
 342         for(node = connection_tree->head; node; node = node->next) {
 343                 c = node->data;
 344
 345                 if(c->outgoing && !c->node) {
 346                         if(timeout_initialized(&c->outgoing->ev))
 347                                 event_del(&c->outgoing->ev);
 348                         if(c->status.connecting)
 349                                 close(c->socket);
 350                         c->outgoing->timeout = 0;
 351                         do_outgoing_connection(c);
 352                 }
 353         }
 354 }
 355
 356 /*
 357   this is where it all happens...
 358 */
 359 int main_loop(void) {
 360         struct event timeout_event;
 361
 362         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 363         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 364
 365 #ifndef HAVE_MINGW
 366         struct event sighup_event;
 367         struct event sigterm_event;
 368         struct event sigquit_event;
 369         struct event sigalrm_event;
 370
 371         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 372         signal_add(&sighup_event, NULL);
 373         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 374         signal_add(&sigterm_event, NULL);
 375         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 376         signal_add(&sigquit_event, NULL);
 377         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 378         signal_add(&sigalrm_event, NULL);
 379 #endif
 380
 381         if(event_loop(0) < 0) {
 382                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 383                 return 1;
 384         }
 385
 386 #ifndef HAVE_MINGW
 387         signal_del(&sighup_event);
 388         signal_del(&sigterm_event);
 389         signal_del(&sigquit_event);
 390         signal_del(&sigalrm_event);
 391 #endif
 392
 393         event_del(&timeout_event);
 394
 395         return 0;
 396 }