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                   2000-2013 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 "conf.h"
  27 #include "connection.h"
  28 #include "device.h"
  29 #include "graph.h"
  30 #include "logger.h"
  31 #include "meta.h"
  32 #include "names.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         logger(DEBUG_PROTOCOL, LOG_DEBUG, "Purging unreachable nodes");
  49
  50         /* Remove all edges and subnets owned by unreachable nodes. */
  51
  52         for splay_each(node_t, n, node_tree) {
  53                 if(!n->status.reachable) {
  54                         logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Purging node %s (%s)", n->name, n->hostname);
  55
  56                         for splay_each(subnet_t, s, n->subnet_tree) {
  57                                 send_del_subnet(everyone, s);
  58                                 if(!strictsubnets)
  59                                         subnet_del(n, s);
  60                         }
  61
  62                         for splay_each(edge_t, e, n->edge_tree) {
  63                                 if(!tunnelserver)
  64                                         send_del_edge(everyone, e);
  65                                 edge_del(e);
  66                         }
  67                 }
  68         }
  69
  70         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  71
  72         for splay_each(node_t, n, node_tree) {
  73                 if(!n->status.reachable) {
  74                         for splay_each(edge_t, e, edge_weight_tree)
  75                                 if(e->to == n)
  76                                         return;
  77
  78                         if(!autoconnect && (!strictsubnets || !n->subnet_tree->head))
  79                                 /* in strictsubnets mode do not delete nodes with subnets */
  80                                 node_del(n);
  81                 }
  82         }
  83 }
  84
  85 /*
  86   Terminate a connection:
  87   - Mark it as inactive
  88   - Remove the edge representing this connection
  89   - Kill it with fire
  90   - Check if we need to retry making an outgoing connection
  91 */
  92 void terminate_connection(connection_t *c, bool report) {
  93         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)", c->name, c->hostname);
  94
  95         c->status.active = false;
  96
  97         if(c->node && c->node->connection == c)
  98                 c->node->connection = NULL;
  99
 100         if(c->edge) {
 101                 if(report && !tunnelserver)
 102                         send_del_edge(everyone, c->edge);
 103
 104                 edge_del(c->edge);
 105                 c->edge = NULL;
 106
 107                 /* Run MST and SSSP algorithms */
 108
 109                 graph();
 110
 111                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 112
 113                 if(report && !c->node->status.reachable) {
 114                         edge_t *e;
 115                         e = lookup_edge(c->node, myself);
 116                         if(e) {
 117                                 if(!tunnelserver)
 118                                         send_del_edge(everyone, e);
 119                                 edge_del(e);
 120                         }
 121                 }
 122         }
 123
 124         outgoing_t *outgoing = c->outgoing;
 125         connection_del(c);
 126
 127         /* Check if this was our outgoing connection */
 128
 129         if(outgoing)
 130                 do_outgoing_connection(outgoing);
 131 }
 132
 133 /*
 134   Check if the other end is active.
 135   If we have sent packets, but didn't receive any,
 136   then possibly the other end is dead. We send a
 137   PING request over the meta connection. If the other
 138   end does not reply in time, we consider them dead
 139   and close the connection.
 140 */
 141 static void timeout_handler(void *data) {
 142         for list_each(connection_t, c, connection_list) {
 143                 if(c->status.control)
 144                         continue;
 145
 146                 if(c->last_ping_time + pingtimeout <= now.tv_sec) {
 147                         if(c->status.active) {
 148                                 if(c->status.pinged) {
 149                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds", c->name, c->hostname, (long)now.tv_sec - c->last_ping_time);
 150                                 } else if(c->last_ping_time + pinginterval <= now.tv_sec) {
 151                                         send_ping(c);
 152                                         continue;
 153                                 } else {
 154                                         continue;
 155                                 }
 156                         } else {
 157                                 if(c->status.connecting)
 158                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 159                                 else
 160                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 161                         }
 162                         terminate_connection(c, c->status.active);
 163                 }
 164         }
 165
 166         timeout_set(data, &(struct timeval){pingtimeout, rand() % 100000});
 167 }
 168
 169 static void periodic_handler(void *data) {
 170         /* Check if there are too many contradicting ADD_EDGE and DEL_EDGE messages.
 171            This usually only happens when another node has the same Name as this node.
 172            If so, sleep for a short while to prevent a storm of contradicting messages.
 173         */
 174
 175         if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
 176                 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
 177                 usleep(sleeptime * 1000000LL);
 178                 sleeptime *= 2;
 179                 if(sleeptime < 0)
 180                         sleeptime = 3600;
 181         } else {
 182                 sleeptime /= 2;
 183                 if(sleeptime < 10)
 184                         sleeptime = 10;
 185         }
 186
 187         contradicting_add_edge = 0;
 188         contradicting_del_edge = 0;
 189
 190         /* If AutoConnect is set, check if we need to make or break connections. */
 191
 192         if(autoconnect && node_tree->count > 1) {
 193                 /* Count number of active connections */
 194                 int nc = 0;
 195                 for list_each(connection_t, c, connection_list) {
 196                         if(c->status.active && !c->status.control)
 197                                 nc++;
 198                 }
 199
 200                 if(nc < autoconnect) {
 201                         /* Not enough active connections, try to add one.
 202                            Choose a random node, if we don't have a connection to it,
 203                            and we are not already trying to make one, create an
 204                            outgoing connection to this node.
 205                         */
 206                         int r = rand() % node_tree->count;
 207                         int i = 0;
 208
 209                         for splay_each(node_t, n, node_tree) {
 210                                 if(i++ != r)
 211                                         continue;
 212
 213                                 if(n->connection)
 214                                         break;
 215
 216                                 bool found = false;
 217
 218                                 for list_each(outgoing_t, outgoing, outgoing_list) {
 219                                         if(!strcmp(outgoing->name, n->name)) {
 220                                                 found = true;
 221                                                 break;
 222                                         }
 223                                 }
 224
 225                                 if(!found) {
 226                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Autoconnecting to %s", n->name);
 227                                         outgoing_t *outgoing = xzalloc(sizeof *outgoing);
 228                                         outgoing->name = xstrdup(n->name);
 229                                         list_insert_tail(outgoing_list, outgoing);
 230                                         setup_outgoing_connection(outgoing);
 231                                 }
 232                                 break;
 233                         }
 234                 } else if(nc > autoconnect) {
 235                         /* Too many active connections, try to remove one.
 236                            Choose a random outgoing connection to a node
 237                            that has at least one other connection.
 238                         */
 239                         int r = rand() % nc;
 240                         int i = 0;
 241
 242                         for list_each(connection_t, c, connection_list) {
 243                                 if(!c->status.active || c->status.control)
 244                                         continue;
 245
 246                                 if(i++ != r)
 247                                         continue;
 248
 249                                 if(!c->outgoing || !c->node || c->node->edge_tree->count < 2)
 250                                         break;
 251
 252                                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Autodisconnecting from %s", c->name);
 253                                 list_delete(outgoing_list, c->outgoing);
 254                                 c->outgoing = NULL;
 255                                 terminate_connection(c, c->status.active);
 256                                 break;
 257                         }
 258                 }
 259
 260                 if(nc >= autoconnect) {
 261                         /* If we have enough active connections,
 262                            remove any pending outgoing connections.
 263                         */
 264                         for list_each(outgoing_t, o, outgoing_list) {
 265                                 bool found = false;
 266                                 for list_each(connection_t, c, connection_list) {
 267                                         if(c->outgoing == o) {
 268                                                 found = true;
 269                                                 break;
 270                                         }
 271                                 }
 272                                 if(!found) {
 273                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Cancelled outgoing connection to %s", o->name);
 274                                         list_delete_node(outgoing_list, node);
 275                                 }
 276                         }
 277                 }
 278         }
 279
 280         timeout_set(data, &(struct timeval){5, rand() % 100000});
 281 }
 282
 283 void handle_meta_connection_data(connection_t *c) {
 284         if (!receive_meta(c)) {
 285                 terminate_connection(c, c->status.active);
 286                 return;
 287         }
 288 }
 289
 290 #ifndef HAVE_MINGW
 291 static void sigterm_handler(void *data) {
 292         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
 293         event_exit();
 294 }
 295
 296 static void sighup_handler(void *data) {
 297         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
 298         reopenlogger();
 299         reload_configuration();
 300 }
 301
 302 static void sigalrm_handler(void *data) {
 303         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
 304         retry();
 305 }
 306 #endif
 307
 308 int reload_configuration(void) {
 309         char *fname = NULL;
 310
 311         /* Reread our own configuration file */
 312
 313         exit_configuration(&config_tree);
 314         init_configuration(&config_tree);
 315
 316         if(!read_server_config()) {
 317                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file, exitting.");
 318                 event_exit();
 319                 return EINVAL;
 320         }
 321
 322         read_config_options(config_tree, NULL);
 323
 324         xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, myself->name);
 325         read_config_file(config_tree, fname);
 326         free(fname);
 327
 328         /* Parse some options that are allowed to be changed while tinc is running */
 329
 330         setup_myself_reloadable();
 331
 332         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 333
 334         if(strictsubnets) {
 335                 for splay_each(subnet_t, subnet, subnet_tree)
 336                         subnet->expires = 1;
 337
 338                 load_all_subnets();
 339
 340                 for splay_each(subnet_t, subnet, subnet_tree) {
 341                         if(subnet->expires == 1) {
 342                                 send_del_subnet(everyone, subnet);
 343                                 if(subnet->owner->status.reachable)
 344                                         subnet_update(subnet->owner, subnet, false);
 345                                 subnet_del(subnet->owner, subnet);
 346                         } else if(subnet->expires == -1) {
 347                                 subnet->expires = 0;
 348                         } else {
 349                                 send_add_subnet(everyone, subnet);
 350                                 if(subnet->owner->status.reachable)
 351                                         subnet_update(subnet->owner, subnet, true);
 352                         }
 353                 }
 354         } else { /* Only read our own subnets back in */
 355                 for splay_each(subnet_t, subnet, myself->subnet_tree)
 356                         if(!subnet->expires)
 357                                 subnet->expires = 1;
 358
 359                 config_t *cfg = lookup_config(config_tree, "Subnet");
 360
 361                 while(cfg) {
 362                         subnet_t *subnet, *s2;
 363
 364                         if(!get_config_subnet(cfg, &subnet))
 365                                 continue;
 366
 367                         if((s2 = lookup_subnet(myself, subnet))) {
 368                                 if(s2->expires == 1)
 369                                         s2->expires = 0;
 370
 371                                 free_subnet(subnet);
 372                         } else {
 373                                 subnet_add(myself, subnet);
 374                                 send_add_subnet(everyone, subnet);
 375                                 subnet_update(myself, subnet, true);
 376                         }
 377
 378                         cfg = lookup_config_next(config_tree, cfg);
 379                 }
 380
 381                 for splay_each(subnet_t, subnet, myself->subnet_tree) {
 382                         if(subnet->expires == 1) {
 383                                 send_del_subnet(everyone, subnet);
 384                                 subnet_update(myself, subnet, false);
 385                                 subnet_del(myself, subnet);
 386                         }
 387                 }
 388         }
 389
 390         /* Try to make outgoing connections */
 391
 392         try_outgoing_connections();
 393
 394         /* Close connections to hosts that have a changed or deleted host config file */
 395
 396         for list_each(connection_t, c, connection_list) {
 397                 if(c->status.control)
 398                         continue;
 399
 400                 xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
 401                 struct stat s;
 402                 if(stat(fname, &s) || s.st_mtime > last_config_check) {
 403                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Host config file of %s has been changed", c->name);
 404                         terminate_connection(c, c->status.active);
 405                 }
 406                 free(fname);
 407         }
 408
 409         last_config_check = now.tv_sec;
 410
 411         return 0;
 412 }
 413
 414 void retry(void) {
 415         for list_each(connection_t, c, connection_list) {
 416                 if(c->outgoing && !c->node) {
 417                         timeout_del(&c->outgoing->ev);
 418                         if(c->status.connecting)
 419                                 close(c->socket);
 420                         c->outgoing->timeout = 0;
 421                         terminate_connection(c, c->status.active);
 422                 }
 423         }
 424 }
 425
 426 /*
 427   this is where it all happens...
 428 */
 429 int main_loop(void) {
 430         timeout_t pingtimer = {{0}};
 431         timeout_t periodictimer = {{0}};
 432
 433         timeout_add(&pingtimer, timeout_handler, &pingtimer, &(struct timeval){pingtimeout, rand() % 100000});
 434         timeout_add(&periodictimer, periodic_handler, &periodictimer, &(struct timeval){pingtimeout, rand() % 100000});
 435
 436 #ifndef HAVE_MINGW
 437         signal_t sighup = {0};
 438         signal_t sigterm = {0};
 439         signal_t sigquit = {0};
 440         signal_t sigint = {0};
 441         signal_t sigalrm = {0};
 442
 443         signal_add(&sighup, sighup_handler, &sighup, SIGHUP);
 444         signal_add(&sigterm, sigterm_handler, &sigterm, SIGTERM);
 445         signal_add(&sigquit, sigterm_handler, &sigquit, SIGQUIT);
 446         signal_add(&sigint, sigterm_handler, &sigint, SIGINT);
 447         signal_add(&sigalrm, sigalrm_handler, &sigalrm, SIGALRM);
 448 #endif
 449
 450         if(!event_loop()) {
 451                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 452                 return 1;
 453         }
 454
 455 #ifndef HAVE_MINGW
 456         signal_del(&sighup);
 457         signal_del(&sigalrm);
 458         signal_del(&sigquit);
 459         signal_del(&sigterm);
 460 #endif
 461
 462         timeout_del(&periodictimer);
 463         timeout_del(&pingtimer);
 464
 465         return 0;
 466 }