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                   2000-2011 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
  43 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  44
  45 void purge(void) {
  46         splay_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
  47         node_t *n;
  48         edge_t *e;
  49         subnet_t *s;
  50
  51         ifdebug(PROTOCOL) logger(LOG_DEBUG, "Purging unreachable nodes");
  52
  53         /* Remove all edges and subnets owned by unreachable nodes. */
  54
  55         for(nnode = node_tree->head; nnode; nnode = nnext) {
  56                 nnext = nnode->next;
  57                 n = nnode->data;
  58
  59                 if(!n->status.reachable) {
  60                         ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Purging node %s (%s)", n->name,
  61                                            n->hostname);
  62
  63                         for(snode = n->subnet_tree->head; snode; snode = snext) {
  64                                 snext = snode->next;
  65                                 s = snode->data;
  66                                 send_del_subnet(broadcast, s);
  67                                 if(!strictsubnets)
  68                                         subnet_del(n, s);
  69                         }
  70
  71                         for(enode = n->edge_tree->head; enode; enode = enext) {
  72                                 enext = enode->next;
  73                                 e = enode->data;
  74                                 if(!tunnelserver)
  75                                         send_del_edge(broadcast, e);
  76                                 edge_del(e);
  77                         }
  78                 }
  79         }
  80
  81         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  82
  83         for(nnode = node_tree->head; nnode; nnode = nnext) {
  84                 nnext = nnode->next;
  85                 n = nnode->data;
  86
  87                 if(!n->status.reachable) {
  88                         for(enode = edge_weight_tree->head; enode; enode = enext) {
  89                                 enext = enode->next;
  90                                 e = enode->data;
  91
  92                                 if(e->to == n)
  93                                         break;
  94                         }
  95
  96                         if(!enode && (!strictsubnets || !n->subnet_tree->head))
  97                                 /* in strictsubnets mode do not delete nodes with subnets */
  98                                 node_del(n);
  99                 }
 100         }
 101 }
 102
 103 /*
 104   Terminate a connection:
 105   - Close the socket
 106   - Remove associated edge and tell other connections about it if report = true
 107   - Check if we need to retry making an outgoing connection
 108   - Deactivate the host
 109 */
 110 void terminate_connection(connection_t *c, bool report) {
 111         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Closing connection with %s (%s)",
 112                            c->name, c->hostname);
 113
 114         c->status.active = false;
 115
 116         if(c->node)
 117                 c->node->connection = NULL;
 118
 119         if(c->socket)
 120                 closesocket(c->socket);
 121
 122         if(c->edge) {
 123                 if(report && !tunnelserver)
 124                         send_del_edge(broadcast, c->edge);
 125
 126                 edge_del(c->edge);
 127
 128                 /* Run MST and SSSP algorithms */
 129
 130                 graph();
 131
 132                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 133
 134                 if(report && !c->node->status.reachable) {
 135                         edge_t *e;
 136                         e = lookup_edge(c->node, myself);
 137                         if(e) {
 138                                 if(!tunnelserver)
 139                                         send_del_edge(broadcast, e);
 140                                 edge_del(e);
 141                         }
 142                 }
 143         }
 144
 145         /* Check if this was our outgoing connection */
 146
 147         if(c->outgoing)
 148                 retry_outgoing(c->outgoing);
 149
 150         connection_del(c);
 151 }
 152
 153 /*
 154   Check if the other end is active.
 155   If we have sent packets, but didn't receive any,
 156   then possibly the other end is dead. We send a
 157   PING request over the meta connection. If the other
 158   end does not reply in time, we consider them dead
 159   and close the connection.
 160 */
 161 static void timeout_handler(int fd, short events, void *event) {
 162         splay_node_t *node, *next;
 163         connection_t *c;
 164         time_t now = time(NULL);
 165
 166         for(node = connection_tree->head; node; node = next) {
 167                 next = node->next;
 168                 c = node->data;
 169
 170                 if(c->last_ping_time + pingtimeout <= now) {
 171                         if(c->status.active) {
 172                                 if(c->status.pinged) {
 173                                         ifdebug(CONNECTIONS) logger(LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
 174                                                            c->name, c->hostname, now - c->last_ping_time);
 175                                         terminate_connection(c, true);
 176                                         continue;
 177                                 } else if(c->last_ping_time + pinginterval <= now) {
 178                                         send_ping(c);
 179                                 }
 180                         } else {
 181                                 if(c->status.connecting) {
 182                                         ifdebug(CONNECTIONS)
 183                                                 logger(LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 184                                         c->status.connecting = false;
 185                                         closesocket(c->socket);
 186                                         do_outgoing_connection(c);
 187                                 } else {
 188                                         ifdebug(CONNECTIONS) logger(LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 189                                         terminate_connection(c, false);
 190                                         continue;
 191                                 }
 192                         }
 193                 }
 194         }
 195
 196         if(contradicting_del_edge && contradicting_add_edge) {
 197                 logger(LOG_WARNING, "Possible node with same Name as us!");
 198
 199                 if(rand() % 3 == 0) {
 200                         logger(LOG_ERR, "Shutting down, check configuration of all nodes for duplicate Names!");
 201                         event_loopexit(NULL);
 202                         return;
 203                 }
 204
 205                 contradicting_add_edge = 0;
 206                 contradicting_del_edge = 0;
 207         }
 208
 209         event_add(event, &(struct timeval){pingtimeout, 0});
 210 }
 211
 212 void handle_meta_connection_data(int fd, short events, void *data) {
 213         connection_t *c = data;
 214         int result;
 215         socklen_t len = sizeof result;
 216
 217         if(c->status.connecting) {
 218                 c->status.connecting = false;
 219
 220                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 221
 222                 if(!result)
 223                         finish_connecting(c);
 224                 else {
 225                         ifdebug(CONNECTIONS) logger(LOG_DEBUG,
 226                                            "Error while connecting to %s (%s): %s",
 227                                            c->name, c->hostname, sockstrerror(result));
 228                         closesocket(c->socket);
 229                         do_outgoing_connection(c);
 230                         return;
 231                 }
 232         }
 233
 234         if (!receive_meta(c)) {
 235                 terminate_connection(c, c->status.active);
 236                 return;
 237         }
 238 }
 239
 240 static void sigterm_handler(int signal, short events, void *data) {
 241         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 242         event_loopexit(NULL);
 243 }
 244
 245 static void sighup_handler(int signal, short events, void *data) {
 246         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 247         reload_configuration();
 248 }
 249
 250 int reload_configuration(void) {
 251         connection_t *c;
 252         splay_node_t *node, *next;
 253         char *fname;
 254         struct stat s;
 255         static time_t last_config_check = 0;
 256
 257         /* Reread our own configuration file */
 258
 259         exit_configuration(&config_tree);
 260         init_configuration(&config_tree);
 261
 262         if(!read_server_config()) {
 263                 logger(LOG_ERR, "Unable to reread configuration file, exitting.");
 264                 event_loopexit(NULL);
 265                 return EINVAL;
 266         }
 267
 268         /* Close connections to hosts that have a changed or deleted host config file */
 269
 270         for(node = connection_tree->head; node; node = next) {
 271                 c = node->data;
 272                 next = node->next;
 273
 274                 if(c->outgoing) {
 275                         free(c->outgoing->name);
 276                         if(c->outgoing->ai)
 277                                 freeaddrinfo(c->outgoing->ai);
 278                         free(c->outgoing);
 279                         c->outgoing = NULL;
 280                 }
 281
 282                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 283                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 284                         terminate_connection(c, c->status.active);
 285                 free(fname);
 286         }
 287
 288         last_config_check = time(NULL);
 289
 290         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 291
 292         if(strictsubnets) {
 293                 subnet_t *subnet;
 294
 295
 296                 for(node = subnet_tree->head; node; node = node->next) {
 297                         subnet = node->data;
 298                         subnet->expires = 1;
 299                 }
 300
 301                 load_all_subnets();
 302
 303                 for(node = subnet_tree->head; node; node = next) {
 304                         next = node->next;
 305                         subnet = node->data;
 306                         if(subnet->expires == 1) {
 307                                 send_del_subnet(broadcast, subnet);
 308                                 if(subnet->owner->status.reachable)
 309                                         subnet_update(subnet->owner, subnet, false);
 310                                 subnet_del(subnet->owner, subnet);
 311                         } else if(subnet->expires == -1) {
 312                                 subnet->expires = 0;
 313                         } else {
 314                                 send_add_subnet(broadcast, subnet);
 315                                 if(subnet->owner->status.reachable)
 316                                         subnet_update(subnet->owner, subnet, true);
 317                         }
 318                 }
 319         }
 320
 321         /* Try to make outgoing connections */
 322
 323         try_outgoing_connections();
 324
 325         return 0;
 326 }
 327
 328 void retry(void) {
 329         connection_t *c;
 330         splay_node_t *node;
 331
 332         for(node = connection_tree->head; node; node = node->next) {
 333                 c = node->data;
 334
 335                 if(c->outgoing && !c->node) {
 336                         if(timeout_initialized(&c->outgoing->ev))
 337                                 event_del(&c->outgoing->ev);
 338                         if(c->status.connecting)
 339                                 close(c->socket);
 340                         c->outgoing->timeout = 0;
 341                         do_outgoing_connection(c);
 342                 }
 343         }
 344 }
 345
 346 /*
 347   this is where it all happens...
 348 */
 349 int main_loop(void) {
 350         struct event timeout_event;
 351         struct event sighup_event;
 352         struct event sigterm_event;
 353         struct event sigquit_event;
 354
 355         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 356         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 357
 358 #ifdef SIGHUP
 359         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 360         signal_add(&sighup_event, NULL);
 361 #endif
 362 #ifdef SIGTERM
 363         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 364         signal_add(&sigterm_event, NULL);
 365 #endif
 366 #ifdef SIGQUIT
 367         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 368         signal_add(&sigquit_event, NULL);
 369 #endif
 370
 371         if(event_loop(0) < 0) {
 372                 logger(LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 373                 return 1;
 374         }
 375
 376         signal_del(&sighup_event);
 377         signal_del(&sigterm_event);
 378         signal_del(&sigquit_event);
 379
 380         if(timeout_initialized(&timeout_event))
 381                 event_del(&timeout_event);
 382
 383         return 0;
 384 }