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
  43 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  44
  45 void purge(void) {
  46         splay_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
  47         node_t *n;
  48         edge_t *e;
  49         subnet_t *s;
  50
  51         ifdebug(PROTOCOL) logger(LOG_DEBUG, "Purging unreachable nodes");
  52
  53         /* Remove all edges and subnets owned by unreachable nodes. */
  54
  55         for(nnode = node_tree->head; nnode; nnode = nnext) {
  56                 nnext = nnode->next;
  57                 n = nnode->data;
  58
  59                 if(!n->status.reachable) {
  60                         ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Purging node %s (%s)", n->name,
  61                                            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(broadcast, 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(broadcast, 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         ifdebug(CONNECTIONS) logger(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(broadcast, 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(broadcast, 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->last_ping_time + pingtimeout <= now) {
 168                         if(c->status.active) {
 169                                 if(c->status.pinged) {
 170                                         ifdebug(CONNECTIONS) logger(LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
 171                                                            c->name, c->hostname, now - c->last_ping_time);
 172                                         terminate_connection(c, true);
 173                                         continue;
 174                                 } else if(c->last_ping_time + pinginterval <= now) {
 175                                         send_ping(c);
 176                                 }
 177                         } else {
 178                                 if(c->status.connecting) {
 179                                         ifdebug(CONNECTIONS)
 180                                                 logger(LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 181                                         c->status.connecting = false;
 182                                         closesocket(c->socket);
 183                                         do_outgoing_connection(c);
 184                                 } else {
 185                                         ifdebug(CONNECTIONS) logger(LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 186                                         terminate_connection(c, false);
 187                                         continue;
 188                                 }
 189                         }
 190                 }
 191         }
 192
 193         if(contradicting_del_edge && contradicting_add_edge) {
 194                 logger(LOG_WARNING, "Possible node with same Name as us!");
 195
 196                 if(rand() % 3 == 0) {
 197                         logger(LOG_ERR, "Shutting down, check configuration of all nodes for duplicate Names!");
 198                         event_loopexit(NULL);
 199                         return;
 200                 }
 201
 202                 contradicting_add_edge = 0;
 203                 contradicting_del_edge = 0;
 204         }
 205
 206         event_add(event, &(struct timeval){pingtimeout, 0});
 207 }
 208
 209 void handle_meta_connection_data(int fd, short events, void *data) {
 210         connection_t *c = data;
 211         int result;
 212         socklen_t len = sizeof result;
 213
 214         if(c->status.connecting) {
 215                 c->status.connecting = false;
 216
 217                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 218
 219                 if(!result)
 220                         finish_connecting(c);
 221                 else {
 222                         ifdebug(CONNECTIONS) logger(LOG_DEBUG,
 223                                            "Error while connecting to %s (%s): %s",
 224                                            c->name, c->hostname, sockstrerror(result));
 225                         closesocket(c->socket);
 226                         do_outgoing_connection(c);
 227                         return;
 228                 }
 229         }
 230
 231         if (!receive_meta(c)) {
 232                 terminate_connection(c, c->status.active);
 233                 return;
 234         }
 235 }
 236
 237 static void sigterm_handler(int signal, short events, void *data) {
 238         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 239         event_loopexit(NULL);
 240 }
 241
 242 static void sighup_handler(int signal, short events, void *data) {
 243         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 244         reopenlogger();
 245         reload_configuration();
 246 }
 247
 248 static void sigalrm_handler(int signal, short events, void *data) {
 249         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 250         retry();
 251 }
 252
 253 int reload_configuration(void) {
 254         connection_t *c;
 255         splay_node_t *node, *next;
 256         char *fname;
 257         struct stat s;
 258         static time_t last_config_check = 0;
 259
 260         /* Reread our own configuration file */
 261
 262         exit_configuration(&config_tree);
 263         init_configuration(&config_tree);
 264
 265         if(!read_server_config()) {
 266                 logger(LOG_ERR, "Unable to reread configuration file, exitting.");
 267                 event_loopexit(NULL);
 268                 return EINVAL;
 269         }
 270
 271         /* Close connections to hosts that have a changed or deleted host config file */
 272
 273         for(node = connection_tree->head; node; node = next) {
 274                 c = node->data;
 275                 next = node->next;
 276
 277                 if(c->outgoing) {
 278                         free(c->outgoing->name);
 279                         if(c->outgoing->ai)
 280                                 freeaddrinfo(c->outgoing->ai);
 281                         free(c->outgoing);
 282                         c->outgoing = NULL;
 283                 }
 284
 285                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 286                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 287                         terminate_connection(c, c->status.active);
 288                 free(fname);
 289         }
 290
 291         last_config_check = time(NULL);
 292
 293         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 294
 295         if(strictsubnets) {
 296                 subnet_t *subnet;
 297
 298
 299                 for(node = subnet_tree->head; node; node = node->next) {
 300                         subnet = node->data;
 301                         subnet->expires = 1;
 302                 }
 303
 304                 load_all_subnets();
 305
 306                 for(node = subnet_tree->head; node; node = next) {
 307                         next = node->next;
 308                         subnet = node->data;
 309                         if(subnet->expires == 1) {
 310                                 send_del_subnet(broadcast, subnet);
 311                                 if(subnet->owner->status.reachable)
 312                                         subnet_update(subnet->owner, subnet, false);
 313                                 subnet_del(subnet->owner, subnet);
 314                         } else if(subnet->expires == -1) {
 315                                 subnet->expires = 0;
 316                         } else {
 317                                 send_add_subnet(broadcast, subnet);
 318                                 if(subnet->owner->status.reachable)
 319                                         subnet_update(subnet->owner, subnet, true);
 320                         }
 321                 }
 322         }
 323
 324         /* Try to make outgoing connections */
 325
 326         try_outgoing_connections();
 327
 328         return 0;
 329 }
 330
 331 void retry(void) {
 332         connection_t *c;
 333         splay_node_t *node;
 334
 335         for(node = connection_tree->head; node; node = node->next) {
 336                 c = node->data;
 337
 338                 if(c->outgoing && !c->node) {
 339                         if(timeout_initialized(&c->outgoing->ev))
 340                                 event_del(&c->outgoing->ev);
 341                         if(c->status.connecting)
 342                                 close(c->socket);
 343                         c->outgoing->timeout = 0;
 344                         do_outgoing_connection(c);
 345                 }
 346         }
 347 }
 348
 349 /*
 350   this is where it all happens...
 351 */
 352 int main_loop(void) {
 353         struct event timeout_event;
 354
 355         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 356         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 357
 358 #ifndef HAVE_MINGW
 359         struct event sighup_event;
 360         struct event sigterm_event;
 361         struct event sigquit_event;
 362         struct event sigalrm_event;
 363
 364         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 365         signal_add(&sighup_event, NULL);
 366         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 367         signal_add(&sigterm_event, NULL);
 368         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 369         signal_add(&sigquit_event, NULL);
 370         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 371         signal_add(&sigalrm_event, NULL);
 372 #endif
 373
 374         if(event_loop(0) < 0) {
 375                 logger(LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 376                 return 1;
 377         }
 378
 379 #ifndef HAVE_MINGW
 380         signal_del(&sighup_event);
 381         signal_del(&sigterm_event);
 382         signal_del(&sigquit_event);
 383         signal_del(&sigalrm_event);
 384 #endif
 385
 386         event_del(&timeout_event);
 387
 388         return 0;
 389 }