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 static timeout_t pingtimer;
  45 static timeout_t periodictimer;
  46
  47 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  48
  49 void purge(void) {
  50         logger(DEBUG_PROTOCOL, LOG_DEBUG, "Purging unreachable nodes");
  51
  52         /* Remove all edges and subnets owned by unreachable nodes. */
  53
  54         for splay_each(node_t, n, node_tree) {
  55                 if(!n->status.reachable) {
  56                         logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Purging node %s (%s)", n->name, n->hostname);
  57
  58                         for splay_each(subnet_t, s, n->subnet_tree) {
  59                                 send_del_subnet(everyone, s);
  60                                 if(!strictsubnets)
  61                                         subnet_del(n, s);
  62                         }
  63
  64                         for splay_each(edge_t, e, n->edge_tree) {
  65                                 if(!tunnelserver)
  66                                         send_del_edge(everyone, e);
  67                                 edge_del(e);
  68                         }
  69                 }
  70         }
  71
  72         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  73
  74         for splay_each(node_t, n, node_tree) {
  75                 if(!n->status.reachable) {
  76                         for splay_each(edge_t, e, edge_weight_tree)
  77                                 if(e->to == n)
  78                                         return;
  79
  80                         if(!autoconnect && (!strictsubnets || !n->subnet_tree->head))
  81                                 /* in strictsubnets mode do not delete nodes with subnets */
  82                                 node_del(n);
  83                 }
  84         }
  85 }
  86
  87 /*
  88   Terminate a connection:
  89   - Mark it as inactive
  90   - Remove the edge representing this connection
  91   - Kill it with fire
  92   - Check if we need to retry making an outgoing connection
  93 */
  94 void terminate_connection(connection_t *c, bool report) {
  95         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)", c->name, c->hostname);
  96
  97         c->status.active = false;
  98
  99         if(c->node && c->node->connection == c)
 100                 c->node->connection = NULL;
 101
 102         if(c->edge) {
 103                 if(report && !tunnelserver)
 104                         send_del_edge(everyone, c->edge);
 105
 106                 edge_del(c->edge);
 107                 c->edge = NULL;
 108
 109                 /* Run MST and SSSP algorithms */
 110
 111                 graph();
 112
 113                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 114
 115                 if(report && !c->node->status.reachable) {
 116                         edge_t *e;
 117                         e = lookup_edge(c->node, myself);
 118                         if(e) {
 119                                 if(!tunnelserver)
 120                                         send_del_edge(everyone, e);
 121                                 edge_del(e);
 122                         }
 123                 }
 124         }
 125
 126         outgoing_t *outgoing = c->outgoing;
 127         connection_del(c);
 128
 129         /* Check if this was our outgoing connection */
 130
 131         if(outgoing)
 132                 do_outgoing_connection(outgoing);
 133 }
 134
 135 /*
 136   Check if the other end is active.
 137   If we have sent packets, but didn't receive any,
 138   then possibly the other end is dead. We send a
 139   PING request over the meta connection. If the other
 140   end does not reply in time, we consider them dead
 141   and close the connection.
 142 */
 143 static void timeout_handler(void *data) {
 144         for list_each(connection_t, c, connection_list) {
 145                 if(c->status.control)
 146                         continue;
 147
 148                 if(c->last_ping_time + pingtimeout <= now.tv_sec) {
 149                         if(c->status.active) {
 150                                 if(c->status.pinged) {
 151                                         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);
 152                                 } else if(c->last_ping_time + pinginterval <= now.tv_sec) {
 153                                         send_ping(c);
 154                                         continue;
 155                                 } else {
 156                                         continue;
 157                                 }
 158                         } else {
 159                                 if(c->status.connecting)
 160                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 161                                 else
 162                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 163                         }
 164                         terminate_connection(c, c->status.active);
 165                 }
 166         }
 167
 168         timeout_set(data, &(struct timeval){pingtimeout, rand() % 100000});
 169 }
 170
 171 static void periodic_handler(void *data) {
 172         /* Check if there are too many contradicting ADD_EDGE and DEL_EDGE messages.
 173            This usually only happens when another node has the same Name as this node.
 174            If so, sleep for a short while to prevent a storm of contradicting messages.
 175         */
 176
 177         if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
 178                 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
 179                 usleep(sleeptime * 1000000LL);
 180                 sleeptime *= 2;
 181                 if(sleeptime < 0)
 182                         sleeptime = 3600;
 183         } else {
 184                 sleeptime /= 2;
 185                 if(sleeptime < 10)
 186                         sleeptime = 10;
 187         }
 188
 189         contradicting_add_edge = 0;
 190         contradicting_del_edge = 0;
 191
 192         /* If AutoConnect is set, check if we need to make or break connections. */
 193
 194         if(autoconnect && node_tree->count > 1) {
 195                 /* Count number of active connections */
 196                 int nc = 0;
 197                 for list_each(connection_t, c, connection_list) {
 198                         if(c->status.active && !c->status.control)
 199                                 nc++;
 200                 }
 201
 202                 if(nc < autoconnect) {
 203                         /* Not enough active connections, try to add one.
 204                            Choose a random node, if we don't have a connection to it,
 205                            and we are not already trying to make one, create an
 206                            outgoing connection to this node.
 207                         */
 208                         int r = rand() % node_tree->count;
 209                         int i = 0;
 210
 211                         for splay_each(node_t, n, node_tree) {
 212                                 if(i++ != r)
 213                                         continue;
 214
 215                                 if(n->connection)
 216                                         break;
 217
 218                                 bool found = false;
 219
 220                                 for list_each(outgoing_t, outgoing, outgoing_list) {
 221                                         if(!strcmp(outgoing->name, n->name)) {
 222                                                 found = true;
 223                                                 break;
 224                                         }
 225                                 }
 226
 227                                 if(!found) {
 228                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Autoconnecting to %s", n->name);
 229                                         outgoing_t *outgoing = xzalloc(sizeof *outgoing);
 230                                         outgoing->name = xstrdup(n->name);
 231                                         list_insert_tail(outgoing_list, outgoing);
 232                                         setup_outgoing_connection(outgoing);
 233                                 }
 234                                 break;
 235                         }
 236                 } else if(nc > autoconnect) {
 237                         /* Too many active connections, try to remove one.
 238                            Choose a random outgoing connection to a node
 239                            that has at least one other connection.
 240                         */
 241                         int r = rand() % nc;
 242                         int i = 0;
 243
 244                         for list_each(connection_t, c, connection_list) {
 245                                 if(!c->status.active || c->status.control)
 246                                         continue;
 247
 248                                 if(i++ != r)
 249                                         continue;
 250
 251                                 if(!c->outgoing || !c->node || c->node->edge_tree->count < 2)
 252                                         break;
 253
 254                                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Autodisconnecting from %s", c->name);
 255                                 list_delete(outgoing_list, c->outgoing);
 256                                 c->outgoing = NULL;
 257                                 terminate_connection(c, c->status.active);
 258                                 break;
 259                         }
 260                 }
 261
 262                 if(nc >= autoconnect) {
 263                         /* If we have enough active connections,
 264                            remove any pending outgoing connections.
 265                         */
 266                         for list_each(outgoing_t, o, outgoing_list) {
 267                                 bool found = false;
 268                                 for list_each(connection_t, c, connection_list) {
 269                                         if(c->outgoing == o) {
 270                                                 found = true;
 271                                                 break;
 272                                         }
 273                                 }
 274                                 if(!found) {
 275                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Cancelled outgoing connection to %s", o->name);
 276                                         list_delete_node(outgoing_list, node);
 277                                 }
 278                         }
 279                 }
 280         }
 281
 282         timeout_set(data, &(struct timeval){5, rand() % 100000});
 283 }
 284
 285 void handle_meta_connection_data(connection_t *c) {
 286         if (!receive_meta(c)) {
 287                 terminate_connection(c, c->status.active);
 288                 return;
 289         }
 290 }
 291
 292 #ifndef HAVE_MINGW
 293 static void sigterm_handler(void *data) {
 294         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
 295         event_exit();
 296 }
 297
 298 static void sighup_handler(void *data) {
 299         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
 300         reopenlogger();
 301         reload_configuration();
 302 }
 303
 304 static void sigalrm_handler(void *data) {
 305         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
 306         retry();
 307 }
 308 #endif
 309
 310 int reload_configuration(void) {
 311         char *fname = NULL;
 312
 313         /* Reread our own configuration file */
 314
 315         exit_configuration(&config_tree);
 316         init_configuration(&config_tree);
 317
 318         if(!read_server_config()) {
 319                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file, exitting.");
 320                 event_exit();
 321                 return EINVAL;
 322         }
 323
 324         read_config_options(config_tree, NULL);
 325
 326         xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, myself->name);
 327         read_config_file(config_tree, fname);
 328         free(fname);
 329
 330         /* Parse some options that are allowed to be changed while tinc is running */
 331
 332         setup_myself_reloadable();
 333
 334         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 335
 336         if(strictsubnets) {
 337                 for splay_each(subnet_t, subnet, subnet_tree)
 338                         subnet->expires = 1;
 339
 340                 load_all_subnets();
 341
 342                 for splay_each(subnet_t, subnet, subnet_tree) {
 343                         if(subnet->expires == 1) {
 344                                 send_del_subnet(everyone, subnet);
 345                                 if(subnet->owner->status.reachable)
 346                                         subnet_update(subnet->owner, subnet, false);
 347                                 subnet_del(subnet->owner, subnet);
 348                         } else if(subnet->expires == -1) {
 349                                 subnet->expires = 0;
 350                         } else {
 351                                 send_add_subnet(everyone, subnet);
 352                                 if(subnet->owner->status.reachable)
 353                                         subnet_update(subnet->owner, subnet, true);
 354                         }
 355                 }
 356         } else { /* Only read our own subnets back in */
 357                 for splay_each(subnet_t, subnet, myself->subnet_tree)
 358                         if(!subnet->expires)
 359                                 subnet->expires = 1;
 360
 361                 config_t *cfg = lookup_config(config_tree, "Subnet");
 362
 363                 while(cfg) {
 364                         subnet_t *subnet, *s2;
 365
 366                         if(!get_config_subnet(cfg, &subnet))
 367                                 continue;
 368
 369                         if((s2 = lookup_subnet(myself, subnet))) {
 370                                 if(s2->expires == 1)
 371                                         s2->expires = 0;
 372
 373                                 free_subnet(subnet);
 374                         } else {
 375                                 subnet_add(myself, subnet);
 376                                 send_add_subnet(everyone, subnet);
 377                                 subnet_update(myself, subnet, true);
 378                         }
 379
 380                         cfg = lookup_config_next(config_tree, cfg);
 381                 }
 382
 383                 for splay_each(subnet_t, subnet, myself->subnet_tree) {
 384                         if(subnet->expires == 1) {
 385                                 send_del_subnet(everyone, subnet);
 386                                 subnet_update(myself, subnet, false);
 387                                 subnet_del(myself, subnet);
 388                         }
 389                 }
 390         }
 391
 392         /* Try to make outgoing connections */
 393
 394         try_outgoing_connections();
 395
 396         /* Close connections to hosts that have a changed or deleted host config file */
 397
 398         for list_each(connection_t, c, connection_list) {
 399                 if(c->status.control)
 400                         continue;
 401
 402                 xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
 403                 struct stat s;
 404                 if(stat(fname, &s) || s.st_mtime > last_config_check) {
 405                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Host config file of %s has been changed", c->name);
 406                         terminate_connection(c, c->status.active);
 407                 }
 408                 free(fname);
 409         }
 410
 411         last_config_check = now.tv_sec;
 412
 413         return 0;
 414 }
 415
 416 void retry(void) {
 417         /* Reset the reconnection timers for all outgoing connections */
 418         for list_each(outgoing_t, outgoing, outgoing_list) {
 419                 outgoing->timeout = 0;
 420                 if(outgoing->ev.cb)
 421                         timeout_set(&outgoing->ev, &(struct timeval){0, 0});
 422         }
 423
 424         /* Check for outgoing connections that are in progress, and reset their ping timers */
 425         for list_each(connection_t, c, connection_list) {
 426                 if(c->outgoing && !c->node)
 427                         c->last_ping_time = 0;
 428         }
 429
 430         /* Kick the ping timeout handler */
 431         timeout_set(&pingtimer, &(struct timeval){0, 0});
 432 }
 433
 434 /*
 435   this is where it all happens...
 436 */
 437 int main_loop(void) {
 438         timeout_add(&pingtimer, timeout_handler, &pingtimer, &(struct timeval){pingtimeout, rand() % 100000});
 439         timeout_add(&periodictimer, periodic_handler, &periodictimer, &(struct timeval){pingtimeout, rand() % 100000});
 440
 441 #ifndef HAVE_MINGW
 442         signal_t sighup = {0};
 443         signal_t sigterm = {0};
 444         signal_t sigquit = {0};
 445         signal_t sigint = {0};
 446         signal_t sigalrm = {0};
 447
 448         signal_add(&sighup, sighup_handler, &sighup, SIGHUP);
 449         signal_add(&sigterm, sigterm_handler, &sigterm, SIGTERM);
 450         signal_add(&sigquit, sigterm_handler, &sigquit, SIGQUIT);
 451         signal_add(&sigint, sigterm_handler, &sigint, SIGINT);
 452         signal_add(&sigalrm, sigalrm_handler, &sigalrm, SIGALRM);
 453 #endif
 454
 455         if(!event_loop()) {
 456                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 457                 return 1;
 458         }
 459
 460 #ifndef HAVE_MINGW
 461         signal_del(&sighup);
 462         signal_del(&sigterm);
 463         signal_del(&sigquit);
 464         signal_del(&sigint);
 465         signal_del(&sigalrm);
 466 #endif
 467
 468         timeout_del(&periodictimer);
 469         timeout_del(&pingtimer);
 470
 471         return 0;
 472 }