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
   7     This program is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License along
  18     with this program; if not, write to the Free Software Foundation, Inc.,
  19     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20 */
  21
  22 #include "system.h"
  23
  24 #include "utils.h"
  25 #include "splay_tree.h"
  26 #include "conf.h"
  27 #include "connection.h"
  28 #include "device.h"
  29 #include "graph.h"
  30 #include "logger.h"
  31 #include "meta.h"
  32 #include "net.h"
  33 #include "netutl.h"
  34 #include "process.h"
  35 #include "protocol.h"
  36 #include "subnet.h"
  37 #include "xalloc.h"
  38
  39 int contradicting_add_edge = 0;
  40 int contradicting_del_edge = 0;
  41
  42 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  43
  44 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         ifdebug(PROTOCOL) logger(LOG_DEBUG, "Purging unreachable nodes");
  51
  52         /* Remove all edges and subnets owned by unreachable nodes. */
  53
  54         for(nnode = node_tree->head; nnode; nnode = nnext) {
  55                 nnext = nnode->next;
  56                 n = nnode->data;
  57
  58                 if(!n->status.reachable) {
  59                         ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Purging node %s (%s)", n->name,
  60                                            n->hostname);
  61
  62                         for(snode = n->subnet_tree->head; snode; snode = snext) {
  63                                 snext = snode->next;
  64                                 s = snode->data;
  65                                 send_del_subnet(broadcast, s);
  66                                 if(!strictsubnets)
  67                                         subnet_del(n, s);
  68                         }
  69
  70                         for(enode = n->edge_tree->head; enode; enode = enext) {
  71                                 enext = enode->next;
  72                                 e = enode->data;
  73                                 if(!tunnelserver)
  74                                         send_del_edge(broadcast, e);
  75                                 edge_del(e);
  76                         }
  77                 }
  78         }
  79
  80         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  81
  82         for(nnode = node_tree->head; nnode; nnode = nnext) {
  83                 nnext = nnode->next;
  84                 n = nnode->data;
  85
  86                 if(!n->status.reachable) {
  87                         for(enode = edge_weight_tree->head; enode; enode = enext) {
  88                                 enext = enode->next;
  89                                 e = enode->data;
  90
  91                                 if(e->to == n)
  92                                         break;
  93                         }
  94
  95                         if(!enode && (!strictsubnets || !n->subnet_tree->head))
  96                                 /* in strictsubnets mode do not delete nodes with subnets */
  97                                 node_del(n);
  98                 }
  99         }
 100 }
 101
 102 /*
 103   Terminate a connection:
 104   - Close the socket
 105   - Remove associated edge and tell other connections about it if report = true
 106   - Check if we need to retry making an outgoing connection
 107   - Deactivate the host
 108 */
 109 void terminate_connection(connection_t *c, bool report) {
 110         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Closing connection with %s (%s)",
 111                            c->name, c->hostname);
 112
 113         c->status.active = false;
 114
 115         if(c->node)
 116                 c->node->connection = NULL;
 117
 118         if(c->socket)
 119                 closesocket(c->socket);
 120
 121         if(c->edge) {
 122                 if(report && !tunnelserver)
 123                         send_del_edge(broadcast, c->edge);
 124
 125                 edge_del(c->edge);
 126
 127                 /* Run MST and SSSP algorithms */
 128
 129                 graph();
 130
 131                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 132
 133                 if(report && !c->node->status.reachable) {
 134                         edge_t *e;
 135                         e = lookup_edge(c->node, myself);
 136                         if(e) {
 137                                 if(!tunnelserver)
 138                                         send_del_edge(broadcast, e);
 139                                 edge_del(e);
 140                         }
 141                 }
 142         }
 143
 144         /* Check if this was our outgoing connection */
 145
 146         if(c->outgoing)
 147                 retry_outgoing(c->outgoing);
 148
 149         connection_del(c);
 150 }
 151
 152 /*
 153   Check if the other end is active.
 154   If we have sent packets, but didn't receive any,
 155   then possibly the other end is dead. We send a
 156   PING request over the meta connection. If the other
 157   end does not reply in time, we consider them dead
 158   and close the connection.
 159 */
 160 static void timeout_handler(int fd, short events, void *event) {
 161         splay_node_t *node, *next;
 162         connection_t *c;
 163         time_t now = time(NULL);
 164
 165         for(node = connection_tree->head; node; node = next) {
 166                 next = node->next;
 167                 c = node->data;
 168
 169                 if(c->last_ping_time + pingtimeout < now) {
 170                         if(c->status.active) {
 171                                 if(c->status.pinged) {
 172                                         ifdebug(CONNECTIONS) logger(LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
 173                                                            c->name, c->hostname, now - c->last_ping_time);
 174                                         terminate_connection(c, true);
 175                                         continue;
 176                                 } else if(c->last_ping_time + pinginterval < now) {
 177                                         send_ping(c);
 178                                 }
 179                         } else {
 180                                 if(c->status.connecting) {
 181                                         ifdebug(CONNECTIONS)
 182                                                 logger(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                                         ifdebug(CONNECTIONS) logger(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 && contradicting_add_edge) {
 196                 logger(LOG_WARNING, "Possible node with same Name as us!");
 197
 198                 if(rand() % 3 == 0) {
 199                         logger(LOG_ERR, "Shutting down, check configuration of all nodes for duplicate Names!");
 200                         event_loopexit(NULL);
 201                         return;
 202                 }
 203
 204                 contradicting_add_edge = 0;
 205                 contradicting_del_edge = 0;
 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, sockstrerror(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 sighup_handler(int signal, short events, void *data) {
 245         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 246         reload_configuration();
 247 }
 248
 249 int reload_configuration(void) {
 250         connection_t *c;
 251         splay_node_t *node, *next;
 252         char *fname;
 253         struct stat s;
 254         static time_t last_config_check = 0;
 255
 256         /* Reread our own configuration file */
 257
 258         exit_configuration(&config_tree);
 259         init_configuration(&config_tree);
 260
 261         if(!read_server_config()) {
 262                 logger(LOG_ERR, "Unable to reread configuration file, exitting.");
 263                 event_loopexit(NULL);
 264                 return EINVAL;
 265         }
 266
 267         /* Close connections to hosts that have a changed or deleted host config file */
 268
 269         for(node = connection_tree->head; node; node = next) {
 270                 c = node->data;
 271                 next = node->next;
 272
 273                 if(c->outgoing) {
 274                         free(c->outgoing->name);
 275                         if(c->outgoing->ai)
 276                                 freeaddrinfo(c->outgoing->ai);
 277                         free(c->outgoing);
 278                         c->outgoing = NULL;
 279                 }
 280
 281                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 282                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 283                         terminate_connection(c, c->status.active);
 284                 free(fname);
 285         }
 286
 287         last_config_check = time(NULL);
 288
 289         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 290
 291         if(strictsubnets) {
 292                 subnet_t *subnet;
 293
 294
 295                 for(node = subnet_tree->head; node; node = node->next) {
 296                         subnet = node->data;
 297                         subnet->expires = 1;
 298                 }
 299
 300                 load_all_subnets();
 301
 302                 for(node = subnet_tree->head; node; node = next) {
 303                         next = node->next;
 304                         subnet = node->data;
 305                         if(subnet->expires == 1) {
 306                                 send_del_subnet(broadcast, subnet);
 307                                 if(subnet->owner->status.reachable)
 308                                         subnet_update(subnet->owner, subnet, false);
 309                                 subnet_del(subnet->owner, subnet);
 310                         } else if(subnet->expires == -1) {
 311                                 subnet->expires = 0;
 312                         } else {
 313                                 send_add_subnet(broadcast, subnet);
 314                                 if(subnet->owner->status.reachable)
 315                                         subnet_update(subnet->owner, subnet, true);
 316                         }
 317                 }
 318         }
 319
 320         /* Try to make outgoing connections */
 321
 322         try_outgoing_connections();
 323
 324         return 0;
 325 }
 326
 327 void retry(void) {
 328         connection_t *c;
 329         splay_node_t *node;
 330
 331         for(node = connection_tree->head; node; node = node->next) {
 332                 c = node->data;
 333
 334                 if(c->outgoing && !c->node) {
 335                         if(timeout_initialized(&c->outgoing->ev))
 336                                 event_del(&c->outgoing->ev);
 337                         if(c->status.connecting)
 338                                 close(c->socket);
 339                         c->outgoing->timeout = 0;
 340                         do_outgoing_connection(c);
 341                 }
 342         }
 343 }
 344
 345 /*
 346   this is where it all happens...
 347 */
 348 int main_loop(void) {
 349         struct event timeout_event;
 350         struct event sighup_event;
 351         struct event sigterm_event;
 352         struct event sigquit_event;
 353
 354         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 355         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 356
 357 #ifdef SIGHUP
 358         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 359         signal_add(&sighup_event, NULL);
 360 #endif
 361 #ifdef SIGTERM
 362         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 363         signal_add(&sigterm_event, NULL);
 364 #endif
 365 #ifdef SIGQUIT
 366         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 367         signal_add(&sigquit_event, NULL);
 368 #endif
 369
 370         if(event_loop(0) < 0) {
 371                 logger(LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 372                 return 1;
 373         }
 374
 375         signal_del(&sighup_event);
 376         signal_del(&sigterm_event);
 377         signal_del(&sigquit_event);
 378
 379         if(timeout_initialized(&timeout_event))
 380                 event_del(&timeout_event);
 381
 382         return 0;
 383 }