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                   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                                 if(!tunnelserver)
  63                                         send_del_subnet(broadcast, s);
  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)
  93                                 node_del(n);
  94                 }
  95         }
  96 }
  97
  98 /*
  99   Terminate a connection:
 100   - Close the socket
 101   - Remove associated edge and tell other connections about it if report = true
 102   - Check if we need to retry making an outgoing connection
 103   - Deactivate the host
 104 */
 105 void terminate_connection(connection_t *c, bool report) {
 106         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Closing connection with %s (%s)",
 107                            c->name, c->hostname);
 108
 109         c->status.active = false;
 110
 111         if(c->node)
 112                 c->node->connection = NULL;
 113
 114         if(c->socket)
 115                 closesocket(c->socket);
 116
 117         if(c->edge) {
 118                 if(report && !tunnelserver)
 119                         send_del_edge(broadcast, c->edge);
 120
 121                 edge_del(c->edge);
 122
 123                 /* Run MST and SSSP algorithms */
 124
 125                 graph();
 126
 127                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 128
 129                 if(report && !c->node->status.reachable) {
 130                         edge_t *e;
 131                         e = lookup_edge(c->node, myself);
 132                         if(e) {
 133                                 if(!tunnelserver)
 134                                         send_del_edge(broadcast, e);
 135                                 edge_del(e);
 136                         }
 137                 }
 138         }
 139
 140         /* Check if this was our outgoing connection */
 141
 142         if(c->outgoing)
 143                 retry_outgoing(c->outgoing);
 144
 145         connection_del(c);
 146 }
 147
 148 /*
 149   Check if the other end is active.
 150   If we have sent packets, but didn't receive any,
 151   then possibly the other end is dead. We send a
 152   PING request over the meta connection. If the other
 153   end does not reply in time, we consider them dead
 154   and close the connection.
 155 */
 156 static void timeout_handler(int fd, short events, void *event) {
 157         splay_node_t *node, *next;
 158         connection_t *c;
 159         time_t now = time(NULL);
 160
 161         for(node = connection_tree->head; node; node = next) {
 162                 next = node->next;
 163                 c = node->data;
 164
 165                 if(c->last_ping_time + pingtimeout < now) {
 166                         if(c->status.active) {
 167                                 if(c->status.pinged) {
 168                                         ifdebug(CONNECTIONS) logger(LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
 169                                                            c->name, c->hostname, now - c->last_ping_time);
 170                                         terminate_connection(c, true);
 171                                         continue;
 172                                 } else if(c->last_ping_time + pinginterval < now) {
 173                                         send_ping(c);
 174                                 }
 175                         } else {
 176                                 if(c->status.connecting) {
 177                                         ifdebug(CONNECTIONS)
 178                                                 logger(LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 179                                         c->status.connecting = false;
 180                                         closesocket(c->socket);
 181                                         do_outgoing_connection(c);
 182                                 } else {
 183                                         ifdebug(CONNECTIONS) logger(LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 184                                         terminate_connection(c, false);
 185                                         continue;
 186                                 }
 187                         }
 188                 }
 189         }
 190
 191         event_add(event, &(struct timeval){pingtimeout, 0});
 192 }
 193
 194 void handle_meta_connection_data(int fd, short events, void *data) {
 195         connection_t *c = data;
 196         int result;
 197         socklen_t len = sizeof result;
 198
 199         if(c->status.connecting) {
 200                 c->status.connecting = false;
 201
 202                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 203
 204                 if(!result)
 205                         finish_connecting(c);
 206                 else {
 207                         ifdebug(CONNECTIONS) logger(LOG_DEBUG,
 208                                            "Error while connecting to %s (%s): %s",
 209                                            c->name, c->hostname, sockstrerror(result));
 210                         closesocket(c->socket);
 211                         do_outgoing_connection(c);
 212                         return;
 213                 }
 214         }
 215
 216         if (!receive_meta(c)) {
 217                 terminate_connection(c, c->status.active);
 218                 return;
 219         }
 220 }
 221
 222 static void sigterm_handler(int signal, short events, void *data) {
 223         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 224         event_loopexit(NULL);
 225 }
 226
 227 static void sighup_handler(int signal, short events, void *data) {
 228         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 229         reload_configuration();
 230 }
 231
 232 int reload_configuration(void) {
 233         connection_t *c;
 234         splay_node_t *node, *next;
 235         char *fname;
 236         struct stat s;
 237         static time_t last_config_check = 0;
 238
 239         /* Reread our own configuration file */
 240
 241         exit_configuration(&config_tree);
 242         init_configuration(&config_tree);
 243
 244         if(!read_server_config()) {
 245                 logger(LOG_ERR, "Unable to reread configuration file, exitting.");
 246                 event_loopexit(NULL);
 247                 return EINVAL;
 248         }
 249
 250         /* Close connections to hosts that have a changed or deleted host config file */
 251
 252         for(node = connection_tree->head; node; node = next) {
 253                 c = node->data;
 254                 next = node->next;
 255
 256                 if(c->outgoing) {
 257                         free(c->outgoing->name);
 258                         if(c->outgoing->ai)
 259                                 freeaddrinfo(c->outgoing->ai);
 260                         free(c->outgoing);
 261                         c->outgoing = NULL;
 262                 }
 263
 264                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 265                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 266                         terminate_connection(c, c->status.active);
 267                 free(fname);
 268         }
 269
 270         last_config_check = time(NULL);
 271
 272         /* Try to make outgoing connections */
 273
 274         try_outgoing_connections();
 275
 276         return 0;
 277 }
 278
 279 void retry(void) {
 280         connection_t *c;
 281         splay_node_t *node;
 282
 283         for(node = connection_tree->head; node; node = node->next) {
 284                 c = node->data;
 285
 286                 if(c->outgoing && !c->node) {
 287                         if(timeout_initialized(&c->outgoing->ev))
 288                                 event_del(&c->outgoing->ev);
 289                         if(c->status.connecting)
 290                                 close(c->socket);
 291                         c->outgoing->timeout = 0;
 292                         do_outgoing_connection(c);
 293                 }
 294         }
 295 }
 296
 297 /*
 298   this is where it all happens...
 299 */
 300 int main_loop(void) {
 301         struct event timeout_event;
 302         struct event sighup_event;
 303         struct event sigterm_event;
 304         struct event sigquit_event;
 305
 306         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 307         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 308
 309 #ifdef SIGHUP
 310         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 311         signal_add(&sighup_event, NULL);
 312 #endif
 313 #ifdef SIGTERM
 314         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 315         signal_add(&sigterm_event, NULL);
 316 #endif
 317 #ifdef SIGQUIT
 318         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 319         signal_add(&sigquit_event, NULL);
 320 #endif
 321
 322         if(event_loop(0) < 0) {
 323                 logger(LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 324                 return 1;
 325         }
 326
 327         signal_del(&sighup_event);
 328         signal_del(&sigterm_event);
 329         signal_del(&sigquit_event);
 330         event_del(&timeout_event);
 331
 332         return 0;
 333 }