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                   2000-2010 Guus Sliepen <guus@tinc-vpn.org>
   5                   2006      Scott Lamb <slamb@slamb.org>
   6
   7     This program is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License along
  18     with this program; if not, write to the Free Software Foundation, Inc.,
  19     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20 */
  21
  22 #include "system.h"
  23
  24 #include "utils.h"
  25 #include "splay_tree.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 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  40
  41 void purge(void) {
  42         splay_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
  43         node_t *n;
  44         edge_t *e;
  45         subnet_t *s;
  46
  47         ifdebug(PROTOCOL) logger(LOG_DEBUG, "Purging unreachable nodes");
  48
  49         /* Remove all edges and subnets owned by unreachable nodes. */
  50
  51         for(nnode = node_tree->head; nnode; nnode = nnext) {
  52                 nnext = nnode->next;
  53                 n = nnode->data;
  54
  55                 if(!n->status.reachable) {
  56                         ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Purging node %s (%s)", n->name,
  57                                            n->hostname);
  58
  59                         for(snode = n->subnet_tree->head; snode; snode = snext) {
  60                                 snext = snode->next;
  61                                 s = snode->data;
  62                                 send_del_subnet(broadcast, s);
  63                                 if(!strictsubnets)
  64                                         subnet_del(n, s);
  65                         }
  66
  67                         for(enode = n->edge_tree->head; enode; enode = enext) {
  68                                 enext = enode->next;
  69                                 e = enode->data;
  70                                 if(!tunnelserver)
  71                                         send_del_edge(broadcast, e);
  72                                 edge_del(e);
  73                         }
  74                 }
  75         }
  76
  77         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  78
  79         for(nnode = node_tree->head; nnode; nnode = nnext) {
  80                 nnext = nnode->next;
  81                 n = nnode->data;
  82
  83                 if(!n->status.reachable) {
  84                         for(enode = edge_weight_tree->head; enode; enode = enext) {
  85                                 enext = enode->next;
  86                                 e = enode->data;
  87
  88                                 if(e->to == n)
  89                                         break;
  90                         }
  91
  92                         if(!enode && (!strictsubnets || !n->subnet_tree->head))
  93                                 /* in strictsubnets mode do not delete nodes with subnets */
  94                                 node_del(n);
  95                 }
  96         }
  97 }
  98
  99 /*
 100   Terminate a connection:
 101   - Close the socket
 102   - Remove associated edge and tell other connections about it if report = true
 103   - Check if we need to retry making an outgoing connection
 104   - Deactivate the host
 105 */
 106 void terminate_connection(connection_t *c, bool report) {
 107         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Closing connection with %s (%s)",
 108                            c->name, c->hostname);
 109
 110         c->status.active = false;
 111
 112         if(c->node)
 113                 c->node->connection = NULL;
 114
 115         if(c->socket)
 116                 closesocket(c->socket);
 117
 118         if(c->edge) {
 119                 if(report && !tunnelserver)
 120                         send_del_edge(broadcast, c->edge);
 121
 122                 edge_del(c->edge);
 123
 124                 /* Run MST and SSSP algorithms */
 125
 126                 graph();
 127
 128                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 129
 130                 if(report && !c->node->status.reachable) {
 131                         edge_t *e;
 132                         e = lookup_edge(c->node, myself);
 133                         if(e) {
 134                                 if(!tunnelserver)
 135                                         send_del_edge(broadcast, e);
 136                                 edge_del(e);
 137                         }
 138                 }
 139         }
 140
 141         /* Check if this was our outgoing connection */
 142
 143         if(c->outgoing)
 144                 retry_outgoing(c->outgoing);
 145
 146         connection_del(c);
 147 }
 148
 149 /*
 150   Check if the other end is active.
 151   If we have sent packets, but didn't receive any,
 152   then possibly the other end is dead. We send a
 153   PING request over the meta connection. If the other
 154   end does not reply in time, we consider them dead
 155   and close the connection.
 156 */
 157 static void timeout_handler(int fd, short events, void *event) {
 158         splay_node_t *node, *next;
 159         connection_t *c;
 160         time_t now = time(NULL);
 161
 162         for(node = connection_tree->head; node; node = next) {
 163                 next = node->next;
 164                 c = node->data;
 165
 166                 if(c->last_ping_time + pingtimeout < now) {
 167                         if(c->status.active) {
 168                                 if(c->status.pinged) {
 169                                         ifdebug(CONNECTIONS) logger(LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
 170                                                            c->name, c->hostname, now - c->last_ping_time);
 171                                         terminate_connection(c, true);
 172                                         continue;
 173                                 } else if(c->last_ping_time + pinginterval < now) {
 174                                         send_ping(c);
 175                                 }
 176                         } else {
 177                                 if(c->status.connecting) {
 178                                         ifdebug(CONNECTIONS)
 179                                                 logger(LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 180                                         c->status.connecting = false;
 181                                         closesocket(c->socket);
 182                                         do_outgoing_connection(c);
 183                                 } else {
 184                                         ifdebug(CONNECTIONS) logger(LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 185                                         terminate_connection(c, false);
 186                                         continue;
 187                                 }
 188                         }
 189                 }
 190         }
 191
 192         event_add(event, &(struct timeval){pingtimeout, 0});
 193 }
 194
 195 void handle_meta_connection_data(int fd, short events, void *data) {
 196         connection_t *c = data;
 197         int result;
 198         socklen_t len = sizeof result;
 199
 200         if(c->status.connecting) {
 201                 c->status.connecting = false;
 202
 203                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 204
 205                 if(!result)
 206                         finish_connecting(c);
 207                 else {
 208                         ifdebug(CONNECTIONS) logger(LOG_DEBUG,
 209                                            "Error while connecting to %s (%s): %s",
 210                                            c->name, c->hostname, sockstrerror(result));
 211                         closesocket(c->socket);
 212                         do_outgoing_connection(c);
 213                         return;
 214                 }
 215         }
 216
 217         if (!receive_meta(c)) {
 218                 terminate_connection(c, c->status.active);
 219                 return;
 220         }
 221 }
 222
 223 static void sigterm_handler(int signal, short events, void *data) {
 224         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 225         event_loopexit(NULL);
 226 }
 227
 228 static void sighup_handler(int signal, short events, void *data) {
 229         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 230         reload_configuration();
 231 }
 232
 233 int reload_configuration(void) {
 234         connection_t *c;
 235         splay_node_t *node, *next;
 236         char *fname;
 237         struct stat s;
 238         static time_t last_config_check = 0;
 239
 240         /* Reread our own configuration file */
 241
 242         exit_configuration(&config_tree);
 243         init_configuration(&config_tree);
 244
 245         if(!read_server_config()) {
 246                 logger(LOG_ERR, "Unable to reread configuration file, exitting.");
 247                 event_loopexit(NULL);
 248                 return EINVAL;
 249         }
 250
 251         /* Close connections to hosts that have a changed or deleted host config file */
 252
 253         for(node = connection_tree->head; node; node = next) {
 254                 c = node->data;
 255                 next = node->next;
 256
 257                 if(c->outgoing) {
 258                         free(c->outgoing->name);
 259                         if(c->outgoing->ai)
 260                                 freeaddrinfo(c->outgoing->ai);
 261                         free(c->outgoing);
 262                         c->outgoing = NULL;
 263                 }
 264
 265                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 266                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 267                         terminate_connection(c, c->status.active);
 268                 free(fname);
 269         }
 270
 271         last_config_check = time(NULL);
 272
 273         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
 274
 275         if(strictsubnets) {
 276                 subnet_t *subnet;
 277
 278                 for(node = subnet_tree->head; node; node = node->next) {
 279                         subnet = node->data;
 280                         subnet->expires = 1;
 281                 }
 282
 283                 load_all_subnets();
 284
 285                 for(node = subnet_tree->head; node; node = next) {
 286                         next = node->next;
 287                         subnet = node->data;
 288                         if(subnet->expires == 1) {
 289                                 send_del_subnet(broadcast, subnet);
 290                                 if(subnet->owner->status.reachable)
 291                                         subnet_update(subnet->owner, subnet, false);
 292                                 subnet_del(subnet->owner, subnet);
 293                         } else if(subnet->expires == -1) {
 294                                 subnet->expires = 0;
 295                         } else {
 296                                 send_add_subnet(broadcast, subnet);
 297                                 if(subnet->owner->status.reachable)
 298                                         subnet_update(subnet->owner, subnet, true);
 299                         }
 300                 }
 301         }
 302
 303         /* Try to make outgoing connections */
 304
 305         try_outgoing_connections();
 306
 307         return 0;
 308 }
 309
 310 void retry(void) {
 311         connection_t *c;
 312         splay_node_t *node;
 313
 314         for(node = connection_tree->head; node; node = node->next) {
 315                 c = node->data;
 316
 317                 if(c->outgoing && !c->node) {
 318                         if(timeout_initialized(&c->outgoing->ev))
 319                                 event_del(&c->outgoing->ev);
 320                         if(c->status.connecting)
 321                                 close(c->socket);
 322                         c->outgoing->timeout = 0;
 323                         do_outgoing_connection(c);
 324                 }
 325         }
 326 }
 327
 328 /*
 329   this is where it all happens...
 330 */
 331 int main_loop(void) {
 332         struct event timeout_event;
 333         struct event sighup_event;
 334         struct event sigterm_event;
 335         struct event sigquit_event;
 336
 337         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 338         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 339
 340 #ifdef SIGHUP
 341         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 342         signal_add(&sighup_event, NULL);
 343 #endif
 344 #ifdef SIGTERM
 345         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 346         signal_add(&sigterm_event, NULL);
 347 #endif
 348 #ifdef SIGQUIT
 349         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 350         signal_add(&sigquit_event, NULL);
 351 #endif
 352
 353         if(event_loop(0) < 0) {
 354                 logger(LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 355                 return 1;
 356         }
 357
 358         signal_del(&sighup_event);
 359         signal_del(&sigterm_event);
 360         signal_del(&sigquit_event);
 361         event_del(&timeout_event);
 362
 363         return 0;
 364 }