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 time_t last_config_check = 0;
  44
  45 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  46
  47 void purge(void) {
  48         splay_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
  49         node_t *n;
  50         edge_t *e;
  51         subnet_t *s;
  52
  53         logger(DEBUG_PROTOCOL, LOG_DEBUG, "Purging unreachable nodes");
  54
  55         /* Remove all edges and subnets owned by unreachable nodes. */
  56
  57         for(nnode = node_tree->head; nnode; nnode = nnext) {
  58                 nnext = nnode->next;
  59                 n = nnode->data;
  60
  61                 if(!n->status.reachable) {
  62                         logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Purging node %s (%s)", n->name, n->hostname);
  63
  64                         for(snode = n->subnet_tree->head; snode; snode = snext) {
  65                                 snext = snode->next;
  66                                 s = snode->data;
  67                                 send_del_subnet(everyone, s);
  68                                 if(!strictsubnets)
  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(everyone, 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 && (!strictsubnets || !n->subnet_tree->head))
  98                                 /* in strictsubnets mode do not delete nodes with subnets */
  99                                 node_del(n);
 100                 }
 101         }
 102 }
 103
 104 /*
 105   Terminate a connection:
 106   - Close the socket
 107   - Remove associated edge and tell other connections about it if report = true
 108   - Check if we need to retry making an outgoing connection
 109   - Deactivate the host
 110 */
 111 void terminate_connection(connection_t *c, bool report) {
 112         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)",
 113                            c->name, c->hostname);
 114
 115         c->status.active = false;
 116
 117         if(c->node && c->node->connection == c)
 118                 c->node->connection = NULL;
 119
 120         if(c->edge) {
 121                 if(report && !tunnelserver)
 122                         send_del_edge(everyone, c->edge);
 123
 124                 edge_del(c->edge);
 125                 c->edge = NULL;
 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(everyone, e);
 139                                 edge_del(e);
 140                         }
 141                 }
 142         }
 143
 144         free_connection_partially(c);
 145
 146         /* Check if this was our outgoing connection */
 147
 148         if(c->outgoing) {
 149                 do_outgoing_connection(c);
 150         } else {
 151                 connection_del(c);
 152         }
 153 }
 154
 155 /*
 156   Check if the other end is active.
 157   If we have sent packets, but didn't receive any,
 158   then possibly the other end is dead. We send a
 159   PING request over the meta connection. If the other
 160   end does not reply in time, we consider them dead
 161   and close the connection.
 162 */
 163 static void timeout_handler(int fd, short events, void *event) {
 164         splay_node_t *node, *next;
 165         connection_t *c;
 166         time_t now = time(NULL);
 167
 168         for(node = connection_tree->head; node; node = next) {
 169                 next = node->next;
 170                 c = node->data;
 171
 172                 if(c->status.control)
 173                         continue;
 174
 175                 if(c->last_ping_time + pingtimeout <= now) {
 176                         if(c->status.active) {
 177                                 if(c->status.pinged) {
 178                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
 179                                                            c->name, c->hostname, (long)now - c->last_ping_time);
 180                                         terminate_connection(c, true);
 181                                         continue;
 182                                 } else if(c->last_ping_time + pinginterval <= now) {
 183                                         send_ping(c);
 184                                 }
 185                         } else {
 186                                 if(c->status.connecting) {
 187                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 188                                         c->status.connecting = false;
 189                                         closesocket(c->socket);
 190                                         do_outgoing_connection(c);
 191                                 } else {
 192                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 193                                         terminate_connection(c, false);
 194                                         continue;
 195                                 }
 196                         }
 197                 }
 198         }
 199
 200         if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
 201                 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
 202                 usleep(sleeptime * 1000000LL);
 203                 sleeptime *= 2;
 204                 if(sleeptime < 0)
 205                         sleeptime = 3600;
 206         } else {
 207                 sleeptime /= 2;
 208                 if(sleeptime < 10)
 209                         sleeptime = 10;
 210         }
 211
 212         contradicting_add_edge = 0;
 213         contradicting_del_edge = 0;
 214
 215         event_add(event, &(struct timeval){pingtimeout, 0});
 216 }
 217
 218 void handle_meta_connection_data(int fd, short events, void *data) {
 219         connection_t *c = data;
 220         int result;
 221         socklen_t len = sizeof result;
 222
 223         if(c->status.connecting) {
 224                 c->status.connecting = false;
 225
 226                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 227
 228                 if(!result)
 229                         finish_connecting(c);
 230                 else {
 231                         logger(DEBUG_CONNECTIONS, LOG_DEBUG,
 232                                            "Error while connecting to %s (%s): %s",
 233                                            c->name, c->hostname, sockstrerror(result));
 234                         closesocket(c->socket);
 235                         do_outgoing_connection(c);
 236                         return;
 237                 }
 238         }
 239
 240         if (!receive_meta(c)) {
 241                 terminate_connection(c, c->status.active);
 242                 return;
 243         }
 244 }
 245
 246 static void sigterm_handler(int signal, short events, void *data) {
 247         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 248         event_loopexit(NULL);
 249 }
 250
 251 static void sighup_handler(int signal, short events, void *data) {
 252         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 253         reopenlogger();
 254         reload_configuration();
 255 }
 256
 257 static void sigalrm_handler(int signal, short events, void *data) {
 258         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 259         retry();
 260 }
 261
 262 int reload_configuration(void) {
 263         connection_t *c;
 264         splay_node_t *node, *next;
 265         char *fname;
 266         struct stat s;
 267
 268         /* Reread our own configuration file */
 269
 270         exit_configuration(&config_tree);
 271         init_configuration(&config_tree);
 272
 273         if(!read_server_config()) {
 274                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file, exitting.");
 275                 event_loopexit(NULL);
 276                 return EINVAL;
 277         }
 278
 279         read_config_options(config_tree, NULL);
 280
 281         xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, myself->name);
 282         read_config_file(config_tree, fname);
 283         free(fname);
 284
 285         /* Parse some options that are allowed to be changed while tinc is running */
 286
 287         setup_myself_reloadable();
 288
 289         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 290
 291         if(strictsubnets) {
 292                 subnet_t *subnet;
 293
 294                 for(node = subnet_tree->head; node; node = node->next) {
 295                         subnet = node->data;
 296                         subnet->expires = 1;
 297                 }
 298
 299                 load_all_subnets();
 300
 301                 for(node = subnet_tree->head; node; node = next) {
 302                         next = node->next;
 303                         subnet = node->data;
 304                         if(subnet->expires == 1) {
 305                                 send_del_subnet(everyone, subnet);
 306                                 if(subnet->owner->status.reachable)
 307                                         subnet_update(subnet->owner, subnet, false);
 308                                 subnet_del(subnet->owner, subnet);
 309                         } else if(subnet->expires == -1) {
 310                                 subnet->expires = 0;
 311                         } else {
 312                                 send_add_subnet(everyone, subnet);
 313                                 if(subnet->owner->status.reachable)
 314                                         subnet_update(subnet->owner, subnet, true);
 315                         }
 316                 }
 317         } else { /* Only read our own subnets back in */
 318                 subnet_t *subnet, *s2;
 319
 320                 for(node = myself->subnet_tree->head; node; node = node->next) {
 321                         subnet_t *subnet = node->data;
 322                         logger(DEBUG_ALWAYS, LOG_DEBUG, "subnet %p expires %d", subnet, (int)subnet->expires);
 323                         if(!subnet->expires)
 324                                 subnet->expires = 1;
 325                 }
 326
 327                 config_t *cfg = lookup_config(config_tree, "Subnet");
 328
 329                 while(cfg) {
 330                         if(!get_config_subnet(cfg, &subnet))
 331                                 continue;
 332
 333                         if((s2 = lookup_subnet(myself, subnet))) {
 334                                 logger(DEBUG_ALWAYS, LOG_DEBUG, "read subnet that already exists: %p expires %d", s2, (int)s2->expires);
 335                                 if(s2->expires == 1)
 336                                         s2->expires = 0;
 337
 338                                 free_subnet(subnet);
 339                         } else {
 340                                 logger(DEBUG_ALWAYS, LOG_DEBUG, "read new subnet %p", subnet);
 341                                 subnet_add(myself, subnet);
 342                                 send_add_subnet(everyone, subnet);
 343                                 subnet_update(myself, subnet, true);
 344                         }
 345
 346                         cfg = lookup_config_next(config_tree, cfg);
 347                 }
 348
 349                 for(node = myself->subnet_tree->head; node; node = next) {
 350                         next = node->next;
 351                         subnet_t *subnet = node->data;
 352                         if(subnet->expires == 1) {
 353                                 logger(DEBUG_ALWAYS, LOG_DEBUG, "removed subnet %p", subnet);
 354                                 send_del_subnet(everyone, subnet);
 355                                 subnet_update(myself, subnet, false);
 356                                 subnet_del(myself, subnet);
 357                         }
 358                 }
 359         }
 360
 361         /* Try to make outgoing connections */
 362
 363         try_outgoing_connections();
 364
 365         /* Close connections to hosts that have a changed or deleted host config file */
 366
 367         for(node = connection_tree->head; node; node = next) {
 368                 c = node->data;
 369                 next = node->next;
 370
 371                 if(c->status.control)
 372                         continue;
 373
 374                 xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
 375                 if(stat(fname, &s) || s.st_mtime > last_config_check) {
 376                         fprintf(stderr, "ZOMG %ld > %ld\n", s.st_mtime, last_config_check);
 377                         terminate_connection(c, c->status.active);
 378                 }
 379                 free(fname);
 380         }
 381
 382         last_config_check = time(NULL);
 383
 384         return 0;
 385 }
 386
 387 void retry(void) {
 388         connection_t *c;
 389         splay_node_t *node, *next;
 390
 391         for(node = connection_tree->head; node; node = next) {
 392                 next = node->next;
 393                 c = node->data;
 394
 395                 if(c->outgoing && !c->node) {
 396                         if(timeout_initialized(&c->outgoing->ev))
 397                                 event_del(&c->outgoing->ev);
 398                         if(c->status.connecting)
 399                                 close(c->socket);
 400                         c->outgoing->timeout = 0;
 401                         do_outgoing_connection(c);
 402                 }
 403         }
 404 }
 405
 406 /*
 407   this is where it all happens...
 408 */
 409 int main_loop(void) {
 410         struct event timeout_event;
 411
 412         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 413         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 414
 415 #ifndef HAVE_MINGW
 416         struct event sighup_event;
 417         struct event sigterm_event;
 418         struct event sigquit_event;
 419         struct event sigalrm_event;
 420
 421         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 422         signal_add(&sighup_event, NULL);
 423         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 424         signal_add(&sigterm_event, NULL);
 425         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 426         signal_add(&sigquit_event, NULL);
 427         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 428         signal_add(&sigalrm_event, NULL);
 429 #endif
 430
 431         if(event_loop(0) < 0) {
 432                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 433                 return 1;
 434         }
 435
 436 #ifndef HAVE_MINGW
 437         signal_del(&sighup_event);
 438         signal_del(&sigterm_event);
 439         signal_del(&sigquit_event);
 440         signal_del(&sigalrm_event);
 441 #endif
 442
 443         event_del(&timeout_event);
 444
 445         return 0;
 446 }