git.meshlink.io Git - meshlink/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 "graph.h"
  29 #include "logger.h"
  30 #include "meta.h"
  31 #include "net.h"
  32 #include "netutl.h"
  33 #include "protocol.h"
  34 #include "xalloc.h"
  35
  36 int contradicting_add_edge = 0;
  37 int contradicting_del_edge = 0;
  38 static int sleeptime = 10;
  39 time_t last_config_check = 0;
  40 static timeout_t pingtimer;
  41 static timeout_t periodictimer;
  42
  43 //TODO: move this to a better place
  44 char *confbase;
  45
  46 /* Purge edges of unreachable nodes. Use carefully. */
  47
  48 // TODO: remove
  49 void purge(void) {
  50         logger(DEBUG_PROTOCOL, LOG_DEBUG, "Purging unreachable nodes");
  51
  52         /* Remove all edges 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(edge_t, e, n->edge_tree) {
  59                                 if(!tunnelserver)
  60                                         send_del_edge(everyone, e);
  61                                 edge_del(e);
  62                         }
  63                 }
  64         }
  65
  66         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  67
  68         for splay_each(node_t, n, node_tree) {
  69                 if(!n->status.reachable) {
  70                         for splay_each(edge_t, e, edge_weight_tree)
  71                                 if(e->to == n)
  72                                         return;
  73                 }
  74         }
  75 }
  76
  77 /*
  78   Terminate a connection:
  79   - Mark it as inactive
  80   - Remove the edge representing this connection
  81   - Kill it with fire
  82   - Check if we need to retry making an outgoing connection
  83 */
  84 void terminate_connection(connection_t *c, bool report) {
  85         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)", c->name, c->hostname);
  86
  87         c->status.active = false;
  88
  89         if(c->node && c->node->connection == c)
  90                 c->node->connection = NULL;
  91
  92         if(c->edge) {
  93                 if(report && !tunnelserver)
  94                         send_del_edge(everyone, c->edge);
  95
  96                 edge_del(c->edge);
  97                 c->edge = NULL;
  98
  99                 /* Run MST and SSSP algorithms */
 100
 101                 graph();
 102
 103                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 104
 105                 if(report && !c->node->status.reachable) {
 106                         edge_t *e;
 107                         e = lookup_edge(c->node, myself);
 108                         if(e) {
 109                                 if(!tunnelserver)
 110                                         send_del_edge(everyone, e);
 111                                 edge_del(e);
 112                         }
 113                 }
 114         }
 115
 116         outgoing_t *outgoing = c->outgoing;
 117         connection_del(c);
 118
 119         /* Check if this was our outgoing connection */
 120
 121         if(outgoing)
 122                 do_outgoing_connection(outgoing);
 123
 124 #ifndef HAVE_MINGW
 125         /* Clean up dead proxy processes */
 126
 127         while(waitpid(-1, NULL, WNOHANG) > 0);
 128 #endif
 129 }
 130
 131 /*
 132   Check if the other end is active.
 133   If we have sent packets, but didn't receive any,
 134   then possibly the other end is dead. We send a
 135   PING request over the meta connection. If the other
 136   end does not reply in time, we consider them dead
 137   and close the connection.
 138 */
 139 static void timeout_handler(void *data) {
 140         for list_each(connection_t, c, connection_list) {
 141                 if(c->last_ping_time + pingtimeout <= now.tv_sec) {
 142                         if(c->status.active) {
 143                                 if(c->status.pinged) {
 144                                         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);
 145                                 } else if(c->last_ping_time + pinginterval <= now.tv_sec) {
 146                                         send_ping(c);
 147                                         continue;
 148                                 } else {
 149                                         continue;
 150                                 }
 151                         } else {
 152                                 if(c->status.connecting)
 153                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 154                                 else
 155                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 156                         }
 157                         terminate_connection(c, c->status.active);
 158                 }
 159         }
 160
 161         timeout_set(data, &(struct timeval){pingtimeout, rand() % 100000});
 162 }
 163
 164 static void periodic_handler(void *data) {
 165         /* Check if there are too many contradicting ADD_EDGE and DEL_EDGE messages.
 166            This usually only happens when another node has the same Name as this node.
 167            If so, sleep for a short while to prevent a storm of contradicting messages.
 168         */
 169
 170         if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
 171                 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
 172                 usleep(sleeptime * 1000000LL);
 173                 sleeptime *= 2;
 174                 if(sleeptime < 0)
 175                         sleeptime = 3600;
 176         } else {
 177                 sleeptime /= 2;
 178                 if(sleeptime < 10)
 179                         sleeptime = 10;
 180         }
 181
 182         contradicting_add_edge = 0;
 183         contradicting_del_edge = 0;
 184
 185         /* If AutoConnect is set, check if we need to make or break connections. */
 186
 187         if(autoconnect && node_tree->count > 1) {
 188                 /* Count number of active connections */
 189                 int nc = 0;
 190                 for list_each(connection_t, c, connection_list) {
 191                         if(c->status.active)
 192                                 nc++;
 193                 }
 194
 195                 if(nc < autoconnect) {
 196                         /* Not enough active connections, try to add one.
 197                            Choose a random node, if we don't have a connection to it,
 198                            and we are not already trying to make one, create an
 199                            outgoing connection to this node.
 200                         */
 201                         int r = rand() % node_tree->count;
 202                         int i = 0;
 203
 204                         for splay_each(node_t, n, node_tree) {
 205                                 if(i++ != r)
 206                                         continue;
 207
 208                                 if(n->connection)
 209                                         break;
 210
 211                                 bool found = false;
 212
 213                                 for list_each(outgoing_t, outgoing, outgoing_list) {
 214                                         if(!strcmp(outgoing->name, n->name)) {
 215                                                 found = true;
 216                                                 break;
 217                                         }
 218                                 }
 219
 220                                 if(!found) {
 221                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Autoconnecting to %s", n->name);
 222                                         outgoing_t *outgoing = xzalloc(sizeof *outgoing);
 223                                         outgoing->name = xstrdup(n->name);
 224                                         list_insert_tail(outgoing_list, outgoing);
 225                                         setup_outgoing_connection(outgoing);
 226                                 }
 227                                 break;
 228                         }
 229                 } else if(nc > autoconnect) {
 230                         /* Too many active connections, try to remove one.
 231                            Choose a random outgoing connection to a node
 232                            that has at least one other connection.
 233                         */
 234                         int r = rand() % nc;
 235                         int i = 0;
 236
 237                         for list_each(connection_t, c, connection_list) {
 238                                 if(!c->status.active)
 239                                         continue;
 240
 241                                 if(i++ != r)
 242                                         continue;
 243
 244                                 if(!c->outgoing || !c->node || c->node->edge_tree->count < 2)
 245                                         break;
 246
 247                                 logger(DEBUG_CONNECTIONS, LOG_INFO, "Autodisconnecting from %s", c->name);
 248                                 list_delete(outgoing_list, c->outgoing);
 249                                 c->outgoing = NULL;
 250                                 terminate_connection(c, c->status.active);
 251                                 break;
 252                         }
 253                 }
 254
 255                 if(nc >= autoconnect) {
 256                         /* If we have enough active connections,
 257                            remove any pending outgoing connections.
 258                         */
 259                         for list_each(outgoing_t, o, outgoing_list) {
 260                                 bool found = false;
 261                                 for list_each(connection_t, c, connection_list) {
 262                                         if(c->outgoing == o) {
 263                                                 found = true;
 264                                                 break;
 265                                         }
 266                                 }
 267                                 if(!found) {
 268                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Cancelled outgoing connection to %s", o->name);
 269                                         list_delete_node(outgoing_list, node);
 270                                 }
 271                         }
 272                 }
 273         }
 274
 275         timeout_set(data, &(struct timeval){5, rand() % 100000});
 276 }
 277
 278 void handle_meta_connection_data(connection_t *c) {
 279         if (!receive_meta(c)) {
 280                 terminate_connection(c, c->status.active);
 281                 return;
 282         }
 283 }
 284
 285 #ifndef HAVE_MINGW
 286 static void sigterm_handler(void *data) {
 287         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
 288         event_exit();
 289 }
 290
 291 static void sighup_handler(void *data) {
 292         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
 293         if(reload_configuration())
 294                 exit(1);
 295 }
 296
 297 static void sigalrm_handler(void *data) {
 298         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
 299         retry();
 300 }
 301 #endif
 302
 303 int reload_configuration(void) {
 304         char *fname = NULL;
 305
 306         /* Reread our own configuration file */
 307
 308         exit_configuration(&config_tree);
 309         init_configuration(&config_tree);
 310
 311         if(!read_server_config()) {
 312                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file.");
 313                 return EINVAL;
 314         }
 315
 316         read_config_options(config_tree, NULL);
 317
 318         xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, myself->name);
 319         read_config_file(config_tree, fname);
 320         free(fname);
 321
 322         /* Parse some options that are allowed to be changed while tinc is running */
 323
 324         setup_myself_reloadable();
 325
 326         /* Try to make outgoing connections */
 327
 328         try_outgoing_connections();
 329
 330         /* Close connections to hosts that have a changed or deleted host config file */
 331
 332         for list_each(connection_t, c, connection_list) {
 333                 xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
 334                 struct stat s;
 335                 if(stat(fname, &s) || s.st_mtime > last_config_check) {
 336                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Host config file of %s has been changed", c->name);
 337                         terminate_connection(c, c->status.active);
 338                 }
 339                 free(fname);
 340         }
 341
 342         last_config_check = now.tv_sec;
 343
 344         return 0;
 345 }
 346
 347 void retry(void) {
 348         /* Reset the reconnection timers for all outgoing connections */
 349         for list_each(outgoing_t, outgoing, outgoing_list) {
 350                 outgoing->timeout = 0;
 351                 if(outgoing->ev.cb)
 352                         timeout_set(&outgoing->ev, &(struct timeval){0, 0});
 353         }
 354
 355         /* Check for outgoing connections that are in progress, and reset their ping timers */
 356         for list_each(connection_t, c, connection_list) {
 357                 if(c->outgoing && !c->node)
 358                         c->last_ping_time = 0;
 359         }
 360
 361         /* Kick the ping timeout handler */
 362         timeout_set(&pingtimer, &(struct timeval){0, 0});
 363 }
 364
 365 /*
 366   this is where it all happens...
 367 */
 368 int main_loop(void) {
 369         timeout_add(&pingtimer, timeout_handler, &pingtimer, &(struct timeval){pingtimeout, rand() % 100000});
 370         timeout_add(&periodictimer, periodic_handler, &periodictimer, &(struct timeval){pingtimeout, rand() % 100000});
 371
 372 #ifndef HAVE_MINGW
 373         signal_t sighup = {0};
 374         signal_t sigterm = {0};
 375         signal_t sigquit = {0};
 376         signal_t sigint = {0};
 377         signal_t sigalrm = {0};
 378
 379         signal_add(&sighup, sighup_handler, &sighup, SIGHUP);
 380         signal_add(&sigterm, sigterm_handler, &sigterm, SIGTERM);
 381         signal_add(&sigquit, sigterm_handler, &sigquit, SIGQUIT);
 382         signal_add(&sigint, sigterm_handler, &sigint, SIGINT);
 383         signal_add(&sigalrm, sigalrm_handler, &sigalrm, SIGALRM);
 384 #endif
 385
 386         if(!event_loop()) {
 387                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 388                 return 1;
 389         }
 390
 391 #ifndef HAVE_MINGW
 392         signal_del(&sighup);
 393         signal_del(&sigterm);
 394         signal_del(&sigquit);
 395         signal_del(&sigint);
 396         signal_del(&sigalrm);
 397 #endif
 398
 399         timeout_del(&periodictimer);
 400         timeout_del(&pingtimer);
 401
 402         return 0;
 403 }