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                   2000-2012 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         free_connection_partially(c);
 143
 144         /* Check if this was our outgoing connection */
 145
 146         if(c->outgoing) {
 147                 do_outgoing_connection(c);
 148         }
 149 }
 150
 151 /*
 152   Check if the other end is active.
 153   If we have sent packets, but didn't receive any,
 154   then possibly the other end is dead. We send a
 155   PING request over the meta connection. If the other
 156   end does not reply in time, we consider them dead
 157   and close the connection.
 158 */
 159 static void timeout_handler(int fd, short events, void *event) {
 160         splay_node_t *node, *next;
 161         connection_t *c;
 162         time_t now = time(NULL);
 163
 164         for(node = connection_tree->head; node; node = next) {
 165                 next = node->next;
 166                 c = node->data;
 167
 168                 if(c->status.control)
 169                         continue;
 170
 171                 if(c->last_ping_time + pingtimeout <= now) {
 172                         if(c->status.active) {
 173                                 if(c->status.pinged) {
 174                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
 175                                                            c->name, c->hostname, (long)now - c->last_ping_time);
 176                                         terminate_connection(c, true);
 177                                         continue;
 178                                 } else if(c->last_ping_time + pinginterval <= now) {
 179                                         send_ping(c);
 180                                 }
 181                         } else {
 182                                 if(c->status.connecting) {
 183                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 184                                         c->status.connecting = false;
 185                                         closesocket(c->socket);
 186                                         do_outgoing_connection(c);
 187                                 } else {
 188                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 189                                         terminate_connection(c, false);
 190                                         continue;
 191                                 }
 192                         }
 193                 }
 194         }
 195
 196         if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
 197                 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
 198                 usleep(sleeptime * 1000000LL);
 199                 sleeptime *= 2;
 200                 if(sleeptime < 0)
 201                         sleeptime = 3600;
 202         } else {
 203                 sleeptime /= 2;
 204                 if(sleeptime < 10)
 205                         sleeptime = 10;
 206         }
 207
 208         contradicting_add_edge = 0;
 209         contradicting_del_edge = 0;
 210
 211         event_add(event, &(struct timeval){pingtimeout, 0});
 212 }
 213
 214 void handle_meta_connection_data(int fd, short events, void *data) {
 215         connection_t *c = data;
 216         int result;
 217         socklen_t len = sizeof result;
 218
 219         if(c->status.connecting) {
 220                 c->status.connecting = false;
 221
 222                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 223
 224                 if(!result)
 225                         finish_connecting(c);
 226                 else {
 227                         logger(DEBUG_CONNECTIONS, LOG_DEBUG,
 228                                            "Error while connecting to %s (%s): %s",
 229                                            c->name, c->hostname, sockstrerror(result));
 230                         closesocket(c->socket);
 231                         do_outgoing_connection(c);
 232                         return;
 233                 }
 234         }
 235
 236         if (!receive_meta(c)) {
 237                 terminate_connection(c, c->status.active);
 238                 return;
 239         }
 240 }
 241
 242 static void sigterm_handler(int signal, short events, void *data) {
 243         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 244         event_loopexit(NULL);
 245 }
 246
 247 static void sighup_handler(int signal, short events, void *data) {
 248         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 249         reopenlogger();
 250         reload_configuration();
 251 }
 252
 253 static void sigalrm_handler(int signal, short events, void *data) {
 254         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 255         retry();
 256 }
 257
 258 int reload_configuration(void) {
 259         connection_t *c;
 260         splay_node_t *node, *next;
 261         char *fname;
 262         struct stat s;
 263         static time_t last_config_check = 0;
 264
 265         /* Reread our own configuration file */
 266
 267         exit_configuration(&config_tree);
 268         init_configuration(&config_tree);
 269
 270         if(!read_server_config()) {
 271                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file, exitting.");
 272                 event_loopexit(NULL);
 273                 return EINVAL;
 274         }
 275
 276         /* Close connections to hosts that have a changed or deleted host config file */
 277
 278         for(node = connection_tree->head; node; node = next) {
 279                 c = node->data;
 280                 next = node->next;
 281
 282                 if(c->status.control)
 283                         continue;
 284
 285                 if(c->outgoing) {
 286                         free(c->outgoing->name);
 287                         if(c->outgoing->ai)
 288                                 freeaddrinfo(c->outgoing->ai);
 289                         free(c->outgoing);
 290                         c->outgoing = NULL;
 291                 }
 292
 293                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 294                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 295                         terminate_connection(c, c->status.active);
 296                 free(fname);
 297         }
 298
 299         last_config_check = time(NULL);
 300
 301         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 302
 303         if(strictsubnets) {
 304                 subnet_t *subnet;
 305
 306
 307                 for(node = subnet_tree->head; node; node = node->next) {
 308                         subnet = node->data;
 309                         subnet->expires = 1;
 310                 }
 311
 312                 load_all_subnets();
 313
 314                 for(node = subnet_tree->head; node; node = next) {
 315                         next = node->next;
 316                         subnet = node->data;
 317                         if(subnet->expires == 1) {
 318                                 send_del_subnet(everyone, subnet);
 319                                 if(subnet->owner->status.reachable)
 320                                         subnet_update(subnet->owner, subnet, false);
 321                                 subnet_del(subnet->owner, subnet);
 322                         } else if(subnet->expires == -1) {
 323                                 subnet->expires = 0;
 324                         } else {
 325                                 send_add_subnet(everyone, subnet);
 326                                 if(subnet->owner->status.reachable)
 327                                         subnet_update(subnet->owner, subnet, true);
 328                         }
 329                 }
 330         }
 331
 332         /* Try to make outgoing connections */
 333
 334         try_outgoing_connections();
 335
 336         return 0;
 337 }
 338
 339 void retry(void) {
 340         connection_t *c;
 341         splay_node_t *node;
 342
 343         for(node = connection_tree->head; node; node = node->next) {
 344                 c = node->data;
 345
 346                 if(c->outgoing && !c->node) {
 347                         if(timeout_initialized(&c->outgoing->ev))
 348                                 event_del(&c->outgoing->ev);
 349                         if(c->status.connecting)
 350                                 close(c->socket);
 351                         c->outgoing->timeout = 0;
 352                         do_outgoing_connection(c);
 353                 }
 354         }
 355 }
 356
 357 /*
 358   this is where it all happens...
 359 */
 360 int main_loop(void) {
 361         struct event timeout_event;
 362
 363         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 364         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 365
 366 #ifndef HAVE_MINGW
 367         struct event sighup_event;
 368         struct event sigterm_event;
 369         struct event sigquit_event;
 370         struct event sigalrm_event;
 371
 372         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 373         signal_add(&sighup_event, NULL);
 374         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 375         signal_add(&sigterm_event, NULL);
 376         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 377         signal_add(&sigquit_event, NULL);
 378         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 379         signal_add(&sigalrm_event, NULL);
 380 #endif
 381
 382         if(event_loop(0) < 0) {
 383                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 384                 return 1;
 385         }
 386
 387 #ifndef HAVE_MINGW
 388         signal_del(&sighup_event);
 389         signal_del(&sigterm_event);
 390         signal_del(&sigquit_event);
 391         signal_del(&sigalrm_event);
 392 #endif
 393
 394         event_del(&timeout_event);
 395
 396         return 0;
 397 }