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 <openssl/rand.h>
  25
  26 #include "utils.h"
  27 #include "splay_tree.h"
  28 #include "conf.h"
  29 #include "connection.h"
  30 #include "device.h"
  31 #include "graph.h"
  32 #include "logger.h"
  33 #include "meta.h"
  34 #include "net.h"
  35 #include "netutl.h"
  36 #include "process.h"
  37 #include "protocol.h"
  38 #include "subnet.h"
  39 #include "xalloc.h"
  40
  41 /* Purge edges and subnets of unreachable nodes. Use carefully. */
  42
  43 void purge(void) {
  44         splay_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
  45         node_t *n;
  46         edge_t *e;
  47         subnet_t *s;
  48
  49         ifdebug(PROTOCOL) logger(LOG_DEBUG, "Purging unreachable nodes");
  50
  51         /* Remove all edges and subnets owned by unreachable nodes. */
  52
  53         for(nnode = node_tree->head; nnode; nnode = nnext) {
  54                 nnext = nnode->next;
  55                 n = nnode->data;
  56
  57                 if(!n->status.reachable) {
  58                         ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Purging node %s (%s)", n->name,
  59                                            n->hostname);
  60
  61                         for(snode = n->subnet_tree->head; snode; snode = snext) {
  62                                 snext = snode->next;
  63                                 s = snode->data;
  64                                 if(!tunnelserver)
  65                                         send_del_subnet(broadcast, s);
  66                                 subnet_del(n, s);
  67                         }
  68
  69                         for(enode = n->edge_tree->head; enode; enode = enext) {
  70                                 enext = enode->next;
  71                                 e = enode->data;
  72                                 if(!tunnelserver)
  73                                         send_del_edge(broadcast, e);
  74                                 edge_del(e);
  75                         }
  76                 }
  77         }
  78
  79         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
  80
  81         for(nnode = node_tree->head; nnode; nnode = nnext) {
  82                 nnext = nnode->next;
  83                 n = nnode->data;
  84
  85                 if(!n->status.reachable) {
  86                         for(enode = edge_weight_tree->head; enode; enode = enext) {
  87                                 enext = enode->next;
  88                                 e = enode->data;
  89
  90                                 if(e->to == n)
  91                                         break;
  92                         }
  93
  94                         if(!enode)
  95                                 node_del(n);
  96                 }
  97         }
  98 }
  99
 100 /*
 101   Terminate a connection:
 102   - Close the socket
 103   - Remove associated edge and tell other connections about it if report = true
 104   - Check if we need to retry making an outgoing connection
 105   - Deactivate the host
 106 */
 107 void terminate_connection(connection_t *c, bool report) {
 108         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Closing connection with %s (%s)",
 109                            c->name, c->hostname);
 110
 111         c->status.active = false;
 112
 113         if(c->node)
 114                 c->node->connection = NULL;
 115
 116         if(c->socket)
 117                 closesocket(c->socket);
 118
 119         if(c->edge) {
 120                 if(report && !tunnelserver)
 121                         send_del_edge(broadcast, c->edge);
 122
 123                 edge_del(c->edge);
 124
 125                 /* Run MST and SSSP algorithms */
 126
 127                 graph();
 128
 129                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
 130
 131                 if(report && !c->node->status.reachable) {
 132                         edge_t *e;
 133                         e = lookup_edge(c->node, myself);
 134                         if(e) {
 135                                 if(!tunnelserver)
 136                                         send_del_edge(broadcast, e);
 137                                 edge_del(e);
 138                         }
 139                 }
 140         }
 141
 142         /* Check if this was our outgoing connection */
 143
 144         if(c->outgoing)
 145                 retry_outgoing(c->outgoing);
 146
 147         connection_del(c);
 148 }
 149
 150 /*
 151   Check if the other end is active.
 152   If we have sent packets, but didn't receive any,
 153   then possibly the other end is dead. We send a
 154   PING request over the meta connection. If the other
 155   end does not reply in time, we consider them dead
 156   and close the connection.
 157 */
 158 static void timeout_handler(int fd, short events, void *event) {
 159         splay_node_t *node, *next;
 160         connection_t *c;
 161         time_t now = time(NULL);
 162
 163         for(node = connection_tree->head; node; node = next) {
 164                 next = node->next;
 165                 c = node->data;
 166
 167                 if(c->last_ping_time + pingtimeout < now) {
 168                         if(c->status.active) {
 169                                 if(c->status.pinged) {
 170                                         ifdebug(CONNECTIONS) logger(LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
 171                                                            c->name, c->hostname, now - c->last_ping_time);
 172                                         terminate_connection(c, true);
 173                                         continue;
 174                                 } else if(c->last_ping_time + pinginterval < now) {
 175                                         send_ping(c);
 176                                 }
 177                         } else {
 178                                 if(c->status.connecting) {
 179                                         ifdebug(CONNECTIONS)
 180                                                 logger(LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
 181                                         c->status.connecting = false;
 182                                         closesocket(c->socket);
 183                                         do_outgoing_connection(c);
 184                                 } else {
 185                                         ifdebug(CONNECTIONS) logger(LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
 186                                         terminate_connection(c, false);
 187                                         continue;
 188                                 }
 189                         }
 190                 }
 191         }
 192
 193         event_add(event, &(struct timeval){pingtimeout, 0});
 194 }
 195
 196 void handle_meta_connection_data(int fd, short events, void *data) {
 197         connection_t *c = data;
 198         int result;
 199         socklen_t len = sizeof result;
 200
 201         if(c->status.connecting) {
 202                 c->status.connecting = false;
 203
 204                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
 205
 206                 if(!result)
 207                         finish_connecting(c);
 208                 else {
 209                         ifdebug(CONNECTIONS) logger(LOG_DEBUG,
 210                                            "Error while connecting to %s (%s): %s",
 211                                            c->name, c->hostname, strerror(result));
 212                         closesocket(c->socket);
 213                         do_outgoing_connection(c);
 214                         return;
 215                 }
 216         }
 217
 218         if (!receive_meta(c)) {
 219                 terminate_connection(c, c->status.active);
 220                 return;
 221         }
 222 }
 223
 224 static void sigterm_handler(int signal, short events, void *data) {
 225         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 226         event_loopexit(NULL);
 227 }
 228
 229 static void sighup_handler(int signal, short events, void *data) {
 230         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
 231         reload_configuration();
 232 }
 233
 234 int reload_configuration(void) {
 235         connection_t *c;
 236         splay_node_t *node, *next;
 237         char *fname;
 238         struct stat s;
 239         static time_t last_config_check = 0;
 240
 241         /* Reread our own configuration file */
 242
 243         exit_configuration(&config_tree);
 244         init_configuration(&config_tree);
 245
 246         if(!read_server_config()) {
 247                 logger(LOG_ERR, "Unable to reread configuration file, exitting.");
 248                 event_loopexit(NULL);
 249                 return EINVAL;
 250         }
 251
 252         /* Close connections to hosts that have a changed or deleted host config file */
 253
 254         for(node = connection_tree->head; node; node = next) {
 255                 c = node->data;
 256                 next = node->next;
 257
 258                 if(c->outgoing) {
 259                         free(c->outgoing->name);
 260                         if(c->outgoing->ai)
 261                                 freeaddrinfo(c->outgoing->ai);
 262                         free(c->outgoing);
 263                         c->outgoing = NULL;
 264                 }
 265
 266                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
 267                 if(stat(fname, &s) || s.st_mtime > last_config_check)
 268                         terminate_connection(c, c->status.active);
 269                 free(fname);
 270         }
 271
 272         last_config_check = time(NULL);
 273
 274         /* Try to make outgoing connections */
 275
 276         try_outgoing_connections();
 277
 278         return 0;
 279 }
 280
 281 void retry(void) {
 282         connection_t *c;
 283         splay_node_t *node;
 284
 285         for(node = connection_tree->head; node; node = node->next) {
 286                 c = node->data;
 287
 288                 if(c->outgoing && !c->node) {
 289                         if(timeout_initialized(&c->outgoing->ev))
 290                                 event_del(&c->outgoing->ev);
 291                         if(c->status.connecting)
 292                                 close(c->socket);
 293                         c->outgoing->timeout = 0;
 294                         do_outgoing_connection(c);
 295                 }
 296         }
 297 }
 298
 299 /*
 300   this is where it all happens...
 301 */
 302 int main_loop(void) {
 303         struct event timeout_event;
 304         struct event sighup_event;
 305         struct event sigterm_event;
 306         struct event sigquit_event;
 307
 308         timeout_set(&timeout_event, timeout_handler, &timeout_event);
 309         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
 310         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
 311         signal_add(&sighup_event, NULL);
 312         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
 313         signal_add(&sigterm_event, NULL);
 314         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
 315         signal_add(&sigquit_event, NULL);
 316
 317         if(event_loop(0) < 0) {
 318                 logger(LOG_ERR, "Error while waiting for input: %s", strerror(errno));
 319                 return 1;
 320         }
 321
 322         signal_del(&sighup_event);
 323         signal_del(&sigterm_event);
 324         signal_del(&sigquit_event);
 325         event_del(&timeout_event);
 326
 327         return 0;
 328 }