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>
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.
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.
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.
25 #include <openssl/rand.h>
30 #include "connection.h"
44 bool do_purge = false;
45 volatile bool running = false;
47 bool graph_dump = false;
51 int contradicting_add_edge = 0;
52 int contradicting_del_edge = 0;
53 static int sleeptime = 10;
55 /* Purge edges and subnets of unreachable nodes. Use carefully. */
57 static void purge(void) {
58 avl_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
63 ifdebug(PROTOCOL) logger(LOG_DEBUG, "Purging unreachable nodes");
65 /* Remove all edges and subnets owned by unreachable nodes. */
67 for(nnode = node_tree->head; nnode; nnode = nnext) {
71 if(!n->status.reachable) {
72 ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Purging node %s (%s)", n->name,
75 for(snode = n->subnet_tree->head; snode; snode = snext) {
78 send_del_subnet(everyone, s);
83 for(enode = n->edge_tree->head; enode; enode = enext) {
87 send_del_edge(everyone, e);
93 /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
95 for(nnode = node_tree->head; nnode; nnode = nnext) {
99 if(!n->status.reachable) {
100 for(enode = edge_weight_tree->head; enode; enode = enext) {
108 if(!enode && (!strictsubnets || !n->subnet_tree->head))
109 /* in strictsubnets mode do not delete nodes with subnets */
116 put all file descriptors in an fd_set array
117 While we're at it, purge stuff that needs to be removed.
119 static int build_fdset(fd_set *readset, fd_set *writeset) {
120 avl_node_t *node, *next;
127 for(node = connection_tree->head; node; node = next) {
131 if(c->status.remove) {
133 if(!connection_tree->head)
136 FD_SET(c->socket, readset);
138 FD_SET(c->socket, writeset);
144 for(i = 0; i < listen_sockets; i++) {
145 FD_SET(listen_socket[i].tcp, readset);
146 if(listen_socket[i].tcp > max)
147 max = listen_socket[i].tcp;
148 FD_SET(listen_socket[i].udp, readset);
149 if(listen_socket[i].udp > max)
150 max = listen_socket[i].udp;
154 FD_SET(device_fd, readset);
162 Terminate a connection:
164 - Remove associated edge and tell other connections about it if report = true
165 - Check if we need to retry making an outgoing connection
166 - Deactivate the host
168 void terminate_connection(connection_t *c, bool report) {
172 ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Closing connection with %s (%s)",
173 c->name, c->hostname);
175 c->status.remove = true;
176 c->status.active = false;
179 c->node->connection = NULL;
182 closesocket(c->socket);
185 if(report && !tunnelserver)
186 send_del_edge(everyone, c->edge);
190 /* Run MST and SSSP algorithms */
194 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
196 if(report && !c->node->status.reachable) {
198 e = lookup_edge(c->node, myself);
201 send_del_edge(everyone, e);
207 /* Check if this was our outgoing connection */
210 retry_outgoing(c->outgoing);
222 Check if the other end is active.
223 If we have sent packets, but didn't receive any,
224 then possibly the other end is dead. We send a
225 PING request over the meta connection. If the other
226 end does not reply in time, we consider them dead
227 and close the connection.
229 static void check_dead_connections(void) {
230 avl_node_t *node, *next;
233 for(node = connection_tree->head; node; node = next) {
237 if(c->last_ping_time + pingtimeout <= now) {
238 if(c->status.active) {
239 if(c->status.pinged) {
240 ifdebug(CONNECTIONS) logger(LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
241 c->name, c->hostname, now - c->last_ping_time);
242 c->status.timeout = true;
243 terminate_connection(c, true);
244 } else if(c->last_ping_time + pinginterval <= now) {
248 if(c->status.remove) {
249 logger(LOG_WARNING, "Old connection_t for %s (%s) status %04x still lingering, deleting...",
250 c->name, c->hostname, bitfield_to_int(&c->status, sizeof c->status));
254 ifdebug(CONNECTIONS) logger(LOG_WARNING, "Timeout from %s (%s) during authentication",
255 c->name, c->hostname);
256 if(c->status.connecting) {
257 c->status.connecting = false;
258 closesocket(c->socket);
259 do_outgoing_connection(c);
261 terminate_connection(c, false);
266 if(c->outbuflen > 0 && c->last_flushed_time + pingtimeout <= now) {
267 if(c->status.active) {
268 ifdebug(CONNECTIONS) logger(LOG_INFO,
269 "%s (%s) could not flush for %ld seconds (%d bytes remaining)",
270 c->name, c->hostname, now - c->last_flushed_time, c->outbuflen);
271 c->status.timeout = true;
272 terminate_connection(c, true);
279 check all connections to see if anything
280 happened on their sockets
282 static void check_network_activity(fd_set * readset, fd_set * writeset) {
286 socklen_t len = sizeof(result);
288 static int errors = 0;
290 /* check input from kernel */
291 if(device_fd >= 0 && FD_ISSET(device_fd, readset)) {
292 if(devops.read(&packet)) {
295 route(myself, &packet);
297 usleep(errors * 50000);
300 logger(LOG_ERR, "Too many errors from %s, exiting!", device);
306 /* check meta connections */
307 for(node = connection_tree->head; node; node = node->next) {
313 if(FD_ISSET(c->socket, readset)) {
314 if(c->status.connecting) {
315 c->status.connecting = false;
316 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
319 finish_connecting(c);
321 ifdebug(CONNECTIONS) logger(LOG_DEBUG,
322 "Error while connecting to %s (%s): %s",
323 c->name, c->hostname, sockstrerror(result));
324 closesocket(c->socket);
325 do_outgoing_connection(c);
330 if(!receive_meta(c)) {
331 terminate_connection(c, c->status.active);
336 if(FD_ISSET(c->socket, writeset)) {
338 terminate_connection(c, c->status.active);
344 for(i = 0; i < listen_sockets; i++) {
345 if(FD_ISSET(listen_socket[i].udp, readset))
346 handle_incoming_vpn_data(i);
348 if(FD_ISSET(listen_socket[i].tcp, readset))
349 handle_new_meta_connection(listen_socket[i].tcp);
354 this is where it all happens...
356 int main_loop(void) {
357 fd_set readset, writeset;
360 sigset_t omask, block_mask;
366 time_t last_ping_check, last_config_check, last_graph_dump;
369 last_ping_check = now;
370 last_config_check = now;
371 last_graph_dump = now;
376 if(lookup_config(config_tree, "GraphDumpFile"))
378 /* Block SIGHUP & SIGALRM */
379 sigemptyset(&block_mask);
380 sigaddset(&block_mask, SIGHUP);
381 sigaddset(&block_mask, SIGALRM);
382 sigprocmask(SIG_BLOCK, &block_mask, &omask);
389 next_event = last_ping_check + pingtimeout;
390 if(graph_dump && next_event > last_graph_dump + 60)
391 next_event = last_graph_dump + 60;
393 if((event = peek_next_event()) && next_event > event->time)
394 next_event = event->time;
396 if(next_event <= now)
399 tv.tv_sec = next_event - now;
406 maxfd = build_fdset(&readset, &writeset);
409 LeaveCriticalSection(&mutex);
412 r = pselect(maxfd + 1, &readset, &writeset, NULL, &tv, &omask);
414 r = select(maxfd + 1, &readset, &writeset, NULL, &tv);
418 EnterCriticalSection(&mutex);
422 if(!sockwouldblock(sockerrno)) {
423 logger(LOG_ERR, "Error while waiting for input: %s", sockstrerror(sockerrno));
430 check_network_activity(&readset, &writeset);
437 /* Let's check if everybody is still alive */
439 if(last_ping_check + pingtimeout <= now) {
440 check_dead_connections();
441 last_ping_check = now;
443 if(routing_mode == RMODE_SWITCH)
448 /* Should we regenerate our key? */
450 if(keyexpires <= now) {
454 ifdebug(STATUS) logger(LOG_INFO, "Expiring symmetric keys");
456 for(node = node_tree->head; node; node = node->next) {
465 keyexpires = now + keylifetime;
468 /* Detect ADD_EDGE/DEL_EDGE storms that are caused when
469 * two tinc daemons with the same name are on the VPN.
470 * If so, sleep a while. If this happens multiple times
471 * in a row, sleep longer. */
473 if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
474 logger(LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
475 usleep(sleeptime * 1000000LL);
485 contradicting_add_edge = 0;
486 contradicting_del_edge = 0;
491 logger(LOG_INFO, "Flushing event queue");
493 for(node = connection_tree->head; node; node = node->next) {
494 connection_t *c = node->data;
500 while((event = get_expired_event())) {
501 event->handler(event->data);
507 avl_node_t *node, *next;
515 /* Reread our own configuration file */
517 exit_configuration(&config_tree);
518 init_configuration(&config_tree);
520 if(!read_server_config()) {
521 logger(LOG_ERR, "Unable to reread configuration file, exitting.");
525 /* Cancel non-active outgoing connections */
527 for(node = connection_tree->head; node; node = next) {
533 if(c->status.connecting) {
534 terminate_connection(c, false);
539 /* Wipe list of outgoing connections */
541 for(list_node_t *node = outgoing_list->head; node; node = node->next) {
542 outgoing_t *outgoing = node->data;
545 event_del(outgoing->event);
548 list_delete_list(outgoing_list);
550 /* Close connections to hosts that have a changed or deleted host config file */
552 for(node = connection_tree->head; node; node = node->next) {
555 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
556 if(stat(fname, &s) || s.st_mtime > last_config_check)
557 terminate_connection(c, c->status.active);
561 last_config_check = now;
563 /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
568 for(node = subnet_tree->head; node; node = node->next) {
575 for(node = subnet_tree->head; node; node = next) {
578 if(subnet->expires == 1) {
579 send_del_subnet(everyone, subnet);
580 if(subnet->owner->status.reachable)
581 subnet_update(subnet->owner, subnet, false);
582 subnet_del(subnet->owner, subnet);
583 } else if(subnet->expires == -1) {
586 send_add_subnet(everyone, subnet);
587 if(subnet->owner->status.reachable)
588 subnet_update(subnet->owner, subnet, true);
593 /* Try to make outgoing connections */
595 try_outgoing_connections();
598 /* Dump graph if wanted every 60 seconds*/
600 if(last_graph_dump + 60 <= now) {
602 last_graph_dump = now;
607 /* Restore SIGHUP & SIGALARM mask */
608 sigprocmask(SIG_SETMASK, &omask, NULL);