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                   2000-2009 Guus Sliepen <guus@tinc-vpn.org>
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20     $Id$
  21 */
  22
  23 #include "system.h"
  24
  25 #include <openssl/rand.h>
  26
  27 #include "utils.h"
  28 #include "splay_tree.h"
  29 #include "conf.h"
  30 #include "connection.h"
  31 #include "device.h"
  32 #include "graph.h"
  33 #include "logger.h"
  34 #include "meta.h"
  35 #include "net.h"
  36 #include "netutl.h"
  37 #include "process.h"
  38 #include "protocol.h"
  39 #include "subnet.h"
  40 #include "xalloc.h"
  41
  42 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  43
  44 void purge(void) {
  45         splay_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
  46         node_t *n;
  47         edge_t *e;
  48         subnet_t *s;
  49
  50         cp();
  51
  52         ifdebug(PROTOCOL) logger(LOG_DEBUG, _("Purging unreachable nodes"));
  53
  54         /* Remove all edges and subnets owned by unreachable nodes. */
  55
  56         for(nnode = node_tree->head; nnode; nnode = nnext) {
  57                 nnext = nnode->next;
  58                 n = nnode->data;
  59
  60                 if(!n->status.reachable) {
  61                         ifdebug(SCARY_THINGS) logger(LOG_DEBUG, _("Purging node %s (%s)"), n->name,
  62                                            n->hostname);
  63
  64                         for(snode = n->subnet_tree->head; snode; snode = snext) {
  65                                 snext = snode->next;
  66                                 s = snode->data;
  67                                 if(!tunnelserver)
  68                                         send_del_subnet(broadcast, s);
  69                                 subnet_del(n, s);
  70                         }
  71
  72                         for(enode = n->edge_tree->head; enode; enode = enext) {
  73                                 enext = enode->next;
  74                                 e = enode->data;
  75                                 if(!tunnelserver)
  76                                         send_del_edge(broadcast, e);
  77                                 edge_del(e);
  78                         }
  79                 }
  80         }
  81
  82         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  83
  84         for(nnode = node_tree->head; nnode; nnode = nnext) {
  85                 nnext = nnode->next;
  86                 n = nnode->data;
  87
  88                 if(!n->status.reachable) {
  89                         for(enode = edge_weight_tree->head; enode; enode = enext) {
  90                                 enext = enode->next;
  91                                 e = enode->data;
  92
  93                                 if(e->to == n)
  94                                         break;
  95                         }
  96
  97                         if(!enode)
  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         cp();
 112
 113         ifdebug(CONNECTIONS) logger(LOG_NOTICE, _("Closing connection with %s (%s)"),
 114                            c->name, c->hostname);
 115
 116         c->status.active = false;
 117
 118         if(c->node)
 119                 c->node->connection = NULL;
 120
 121         if(c->socket)
 122                 closesocket(c->socket);
 123
 124         if(c->edge) {
 125                 if(report && !tunnelserver)
 126                         send_del_edge(broadcast, c->edge);
 127
 128                 edge_del(c->edge);
 129
 130                 /* Run MST and SSSP algorithms */
 131
 132                 graph();
 133
 134                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 135
 136                 if(report && !c->node->status.reachable) {
 137                         edge_t *e;
 138                         e = lookup_edge(c->node, myself);
 139                         if(e) {
 140                                 if(!tunnelserver)
 141                                         send_del_edge(broadcast, e);
 142                                 edge_del(e);
 143                         }
 144                 }
 145         }
 146
 147         /* Check if this was our outgoing connection */
 148
 149         if(c->outgoing)
 150                 retry_outgoing(c->outgoing);
 151
 152         connection_del(c);
 153 }
 154
 155 /*
 156   Check if the other end is active.
 157   If we have sent packets, but didn't receive any,
 158   then possibly the other end is dead. We send a
 159   PING request over the meta connection. If the other
 160   end does not reply in time, we consider them dead
 161   and close the connection.
 162 */
 163 static void timeout_handler(int fd, short events, void *event) {
 164         splay_node_t *node, *next;
 165         connection_t *c;
 166         time_t now = time(NULL);
 167
 168         cp();
 169
 170         for(node = connection_tree->head; node; node = next) {
 171                 next = node->next;
 172                 c = node->data;
 173
 174                 if(c->last_ping_time + pingtimeout < now) {
 175                         if(c->status.active) {
 176                                 if(c->status.pinged) {
 177                                         ifdebug(CONNECTIONS) logger(LOG_INFO, _("%s (%s) didn't respond to PING in %ld seconds"),
 178                                                            c->name, c->hostname, now - c->last_ping_time);
 179                                         terminate_connection(c, true);
 180                                         continue;
 181                                 } else if(c->last_ping_time + pinginterval < now) {
 182                                         send_ping(c);
 183                                 }
 184                         } else {
 185                                 if(c->status.connecting) {
 186                                         ifdebug(CONNECTIONS)
 187                                                 logger(LOG_WARNING, _("Timeout while connecting to %s (%s)"), c->name, c->hostname);
 188                                         c->status.connecting = false;
 189                                         closesocket(c->socket);
 190                                         do_outgoing_connection(c);
 191                                 } else {
 192                                         ifdebug(CONNECTIONS) logger(LOG_WARNING, _("Timeout from %s (%s) during authentication"), c->name, c->hostname);
 193                                         terminate_connection(c, false);
 194                                         continue;
 195                                 }
 196                         }
 197                 }
 198         }
 199
 200         event_add(event, &(struct timeval){pingtimeout, 0});
 201 }
 202
 203 void handle_meta_connection_data(int fd, short events, void *data) {
 204         connection_t *c = data;
 205         int result;
 206         socklen_t len = sizeof result;
 207
 208         if(c->status.connecting) {
 209                 c->status.connecting = false;
 210
 211                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 212
 213                 if(!result)
 214                         finish_connecting(c);
 215                 else {
 216                         ifdebug(CONNECTIONS) logger(LOG_DEBUG,
 217                                            _("Error while connecting to %s (%s): %s"),
 218                                            c->name, c->hostname, strerror(result));
 219                         closesocket(c->socket);
 220                         do_outgoing_connection(c);
 221                         return;
 222                 }
 223         }
 224
 225         if (!receive_meta(c)) {
 226                 terminate_connection(c, c->status.active);
 227                 return;
 228         }
 229 }
 230
 231 static void sigterm_handler(int signal, short events, void *data) {
 232         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 233         event_loopexit(NULL);
 234 }
 235
 236 static void sighup_handler(int signal, short events, void *data) {
 237         logger(LOG_NOTICE, _("Got %s signal"), strsignal(signal));
 238         reload_configuration();
 239 }
 240
 241 int reload_configuration(void) {
 242         connection_t *c;
 243         splay_node_t *node, *next;
 244         char *fname;
 245         struct stat s;
 246         static time_t last_config_check = 0;
 247
 248         /* Reread our own configuration file */
 249
 250         exit_configuration(&config_tree);
 251         init_configuration(&config_tree);
 252
 253         if(!read_server_config()) {
 254                 logger(LOG_ERR, _("Unable to reread configuration file, exitting."));
 255                 event_loopexit(NULL);
 256                 return EINVAL;
 257         }
 258
 259         /* Close connections to hosts that have a changed or deleted host config file */
 260
 261         for(node = connection_tree->head; node; node = next) {
 262                 c = node->data;
 263                 next = node->next;
 264
 265                 if(c->outgoing) {
 266                         free(c->outgoing->name);
 267                         if(c->outgoing->ai)
 268                                 freeaddrinfo(c->outgoing->ai);
 269                         free(c->outgoing);
 270                         c->outgoing = NULL;
 271                 }
 272
 273                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 274                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 275                         terminate_connection(c, c->status.active);
 276                 free(fname);
 277         }
 278
 279         last_config_check = time(NULL);
 280
 281         /* Try to make outgoing connections */
 282
 283         try_outgoing_connections();
 284
 285         return 0;
 286 }
 287
 288 void retry(void) {
 289         connection_t *c;
 290         splay_node_t *node;
 291
 292         for(node = connection_tree->head; node; node = node->next) {
 293                 c = node->data;
 294
 295                 if(c->outgoing && !c->node) {
 296                         if(timeout_initialized(&c->outgoing->ev))
 297                                 event_del(&c->outgoing->ev);
 298                         if(c->status.connecting)
 299                                 close(c->socket);
 300                         c->outgoing->timeout = 0;
 301                         do_outgoing_connection(c);
 302                 }
 303         }
 304 }
 305
 306 /*
 307   this is where it all happens...
 308 */
 309 int main_loop(void) {
 310         struct event timeout_event;
 311         struct event sighup_event;
 312         struct event sigterm_event;
 313         struct event sigquit_event;
 314
 315         cp();
 316
 317         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 318         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 319         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 320         signal_add(&sighup_event, NULL);
 321         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 322         signal_add(&sigterm_event, NULL);
 323         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 324         signal_add(&sigquit_event, NULL);
 325
 326         if(event_loop(0) < 0) {
 327                 logger(LOG_ERR, _("Error while waiting for input: %s"), strerror(errno));
 328                 return 1;
 329         }
 330
 331         signal_del(&sighup_event);
 332         signal_del(&sigterm_event);
 333         signal_del(&sigquit_event);
 334         event_del(&timeout_event);
 335
 336         return 0;
 337 }