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 "conf.h"
  27 #include "connection.h"
  28 #include "device.h"
  29 #include "graph.h"
  30 #include "logger.h"
  31 #include "meta.h"
  32 #include "net.h"
  33 #include "netutl.h"
  34 #include "process.h"
  35 #include "protocol.h"
  36 #include "subnet.h"
  37 #include "xalloc.h"
  38
  39 int contradicting_add_edge = 0;
  40 int contradicting_del_edge = 0;
  41 static int sleeptime = 10;
  42 time_t last_config_check = 0;
  43
  44 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  45
  46 void purge(void) {
  47         logger(DEBUG_PROTOCOL, LOG_DEBUG, "Purging unreachable nodes");
  48
  49         /* Remove all edges and subnets owned by unreachable nodes. */
  50
  51         for splay_each(node_t, n, node_tree) {
  52                 if(!n->status.reachable) {
  53                         logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Purging node %s (%s)", n->name, n->hostname);
  54
  55                         for splay_each(subnet_t, s, n->subnet_tree) {
  56                                 send_del_subnet(everyone, s);
  57                                 if(!strictsubnets)
  58                                         subnet_del(n, s);
  59                         }
  60
  61                         for splay_each(edge_t, e, n->edge_tree) {
  62                                 if(!tunnelserver)
  63                                         send_del_edge(everyone, e);
  64                                 edge_del(e);
  65                         }
  66                 }
  67         }
  68
  69         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  70
  71         for splay_each(node_t, n, node_tree) {
  72                 if(!n->status.reachable) {
  73                         for splay_each(edge_t, e, edge_weight_tree)
  74                                 if(e->to == n)
  75                                         return;
  76
  77                         if(!strictsubnets || !n->subnet_tree->head)
  78                                 /* in strictsubnets mode do not delete nodes with subnets */
  79                                 node_del(n);
  80                 }
  81         }
  82 }
  83
  84 /*
  85   Terminate a connection:
  86   - Mark it as inactive
  87   - Remove the edge representing this connection
  88   - Kill it with fire
  89   - Check if we need to retry making an outgoing connection
  90 */
  91 void terminate_connection(connection_t *c, bool report) {
  92         logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)", c->name, c->hostname);
  93
  94         c->status.active = false;
  95
  96         if(c->node && c->node->connection == c)
  97                 c->node->connection = NULL;
  98
  99         if(c->edge) {
 100                 if(report && !tunnelserver)
 101                         send_del_edge(everyone, c->edge);
 102
 103                 edge_del(c->edge);
 104                 c->edge = NULL;
 105
 106                 /* Run MST and SSSP algorithms */
 107
 108                 graph();
 109
 110                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 111
 112                 if(report && !c->node->status.reachable) {
 113                         edge_t *e;
 114                         e = lookup_edge(c->node, myself);
 115                         if(e) {
 116                                 if(!tunnelserver)
 117                                         send_del_edge(everyone, e);
 118                                 edge_del(e);
 119                         }
 120                 }
 121         }
 122
 123         outgoing_t *outgoing = c->outgoing;
 124         connection_del(c);
 125
 126         /* Check if this was our outgoing connection */
 127
 128         if(outgoing)
 129                 do_outgoing_connection(outgoing);
 130 }
 131
 132 /*
 133   Check if the other end is active.
 134   If we have sent packets, but didn't receive any,
 135   then possibly the other end is dead. We send a
 136   PING request over the meta connection. If the other
 137   end does not reply in time, we consider them dead
 138   and close the connection.
 139 */
 140 static void timeout_handler(int fd, short events, void *event) {
 141         time_t now = time(NULL);
 142
 143         for list_each(connection_t, c, connection_list) {
 144                 if(c->status.control)
 145                         continue;
 146
 147                 if(c->last_ping_time + pingtimeout <= now) {
 148                         if(c->status.active) {
 149                                 if(c->status.pinged) {
 150                                         logger(DEBUG_CONNECTIONS, LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds", c->name, c->hostname, (long)now - c->last_ping_time);
 151                                 } else if(c->last_ping_time + pinginterval <= now) {
 152                                         send_ping(c);
 153                                         continue;
 154                                 } else {
 155                                         continue;
 156                                 }
 157                         } else {
 158                                 if(c->status.connecting)
 159                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 160                                 else
 161                                         logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 162                         }
 163                         terminate_connection(c, c->status.active);
 164                 }
 165         }
 166
 167         if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
 168                 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
 169                 usleep(sleeptime * 1000000LL);
 170                 sleeptime *= 2;
 171                 if(sleeptime < 0)
 172                         sleeptime = 3600;
 173         } else {
 174                 sleeptime /= 2;
 175                 if(sleeptime < 10)
 176                         sleeptime = 10;
 177         }
 178
 179         contradicting_add_edge = 0;
 180         contradicting_del_edge = 0;
 181
 182         event_add(event, &(struct timeval){pingtimeout, 0});
 183 }
 184
 185 void handle_meta_connection_data(int fd, short events, void *data) {
 186         connection_t *c = data;
 187         int result;
 188         socklen_t len = sizeof result;
 189
 190         if(c->status.connecting) {
 191                 c->status.connecting = false;
 192
 193                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 194
 195                 if(!result)
 196                         finish_connecting(c);
 197                 else {
 198                         logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(result));
 199                         terminate_connection(c, false);
 200                         return;
 201                 }
 202         }
 203
 204         if (!receive_meta(c)) {
 205                 terminate_connection(c, c->status.active);
 206                 return;
 207         }
 208 }
 209
 210 static void sigterm_handler(int signal, short events, void *data) {
 211         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 212         event_loopexit(NULL);
 213 }
 214
 215 static void sighup_handler(int signal, short events, void *data) {
 216         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 217         reopenlogger();
 218         reload_configuration();
 219 }
 220
 221 static void sigalrm_handler(int signal, short events, void *data) {
 222         logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
 223         retry();
 224 }
 225
 226 int reload_configuration(void) {
 227         char *fname;
 228
 229         /* Reread our own configuration file */
 230
 231         exit_configuration(&config_tree);
 232         init_configuration(&config_tree);
 233
 234         if(!read_server_config()) {
 235                 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file, exitting.");
 236                 event_loopexit(NULL);
 237                 return EINVAL;
 238         }
 239
 240         read_config_options(config_tree, NULL);
 241
 242         xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, myself->name);
 243         read_config_file(config_tree, fname);
 244         free(fname);
 245
 246         /* Parse some options that are allowed to be changed while tinc is running */
 247
 248         setup_myself_reloadable();
 249
 250         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 251
 252         if(strictsubnets) {
 253                 for splay_each(subnet_t, subnet, subnet_tree)
 254                         subnet->expires = 1;
 255
 256                 load_all_subnets();
 257
 258                 for splay_each(subnet_t, subnet, subnet_tree) {
 259                         if(subnet->expires == 1) {
 260                                 send_del_subnet(everyone, subnet);
 261                                 if(subnet->owner->status.reachable)
 262                                         subnet_update(subnet->owner, subnet, false);
 263                                 subnet_del(subnet->owner, subnet);
 264                         } else if(subnet->expires == -1) {
 265                                 subnet->expires = 0;
 266                         } else {
 267                                 send_add_subnet(everyone, subnet);
 268                                 if(subnet->owner->status.reachable)
 269                                         subnet_update(subnet->owner, subnet, true);
 270                         }
 271                 }
 272         } else { /* Only read our own subnets back in */
 273                 for splay_each(subnet_t, subnet, myself->subnet_tree)
 274                         if(!subnet->expires)
 275                                 subnet->expires = 1;
 276
 277                 config_t *cfg = lookup_config(config_tree, "Subnet");
 278
 279                 while(cfg) {
 280                         subnet_t *subnet, *s2;
 281
 282                         if(!get_config_subnet(cfg, &subnet))
 283                                 continue;
 284
 285                         if((s2 = lookup_subnet(myself, subnet))) {
 286                                 if(s2->expires == 1)
 287                                         s2->expires = 0;
 288
 289                                 free_subnet(subnet);
 290                         } else {
 291                                 subnet_add(myself, subnet);
 292                                 send_add_subnet(everyone, subnet);
 293                                 subnet_update(myself, subnet, true);
 294                         }
 295
 296                         cfg = lookup_config_next(config_tree, cfg);
 297                 }
 298
 299                 for splay_each(subnet_t, subnet, myself->subnet_tree) {
 300                         if(subnet->expires == 1) {
 301                                 send_del_subnet(everyone, subnet);
 302                                 subnet_update(myself, subnet, false);
 303                                 subnet_del(myself, subnet);
 304                         }
 305                 }
 306         }
 307
 308         /* Try to make outgoing connections */
 309
 310         try_outgoing_connections();
 311
 312         /* Close connections to hosts that have a changed or deleted host config file */
 313
 314         for list_each(connection_t, c, connection_list) {
 315                 if(c->status.control)
 316                         continue;
 317
 318                 xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
 319                 struct stat s;
 320                 if(stat(fname, &s) || s.st_mtime > last_config_check) {
 321                         logger(DEBUG_CONNECTIONS, LOG_INFO, "Host config file of %s has been changed", c->name);
 322                         terminate_connection(c, c->status.active);
 323                 }
 324                 free(fname);
 325         }
 326
 327         last_config_check = time(NULL);
 328
 329         return 0;
 330 }
 331
 332 void retry(void) {
 333         for list_each(connection_t, c, connection_list) {
 334                 if(c->outgoing && !c->node) {
 335                         if(timeout_initialized(&c->outgoing->ev))
 336                                 event_del(&c->outgoing->ev);
 337                         if(c->status.connecting)
 338                                 close(c->socket);
 339                         c->outgoing->timeout = 0;
 340                         terminate_connection(c, c->status.active);
 341                 }
 342         }
 343 }
 344
 345 /*
 346   this is where it all happens...
 347 */
 348 int main_loop(void) {
 349         struct event timeout_event;
 350
 351         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 352         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 353
 354 #ifndef HAVE_MINGW
 355         struct event sighup_event;
 356         struct event sigterm_event;
 357         struct event sigquit_event;
 358         struct event sigalrm_event;
 359
 360         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 361         signal_add(&sighup_event, NULL);
 362         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 363         signal_add(&sigterm_event, NULL);
 364         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 365         signal_add(&sigquit_event, NULL);
 366         signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
 367         signal_add(&sigalrm_event, NULL);
 368 #endif
 369
 370         if(event_loop(0) < 0) {
 371                 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 372                 return 1;
 373         }
 374
 375 #ifndef HAVE_MINGW
 376         signal_del(&sighup_event);
 377         signal_del(&sigterm_event);
 378         signal_del(&sigquit_event);
 379         signal_del(&sigalrm_event);
 380 #endif
 381
 382         event_del(&timeout_event);
 383
 384         return 0;
 385 }