2 net.c -- most of the network code
3 Copyright (C) 1998-2005 Ivo Timmermans,
4 2000-2015 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);
85 for(enode = n->edge_tree->head; enode; enode = enext) {
90 send_del_edge(everyone, e);
98 /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
100 for(nnode = node_tree->head; nnode; nnode = nnext) {
104 if(!n->status.reachable) {
105 for(enode = edge_weight_tree->head; enode; enode = enext) {
114 if(!enode && (!strictsubnets || !n->subnet_tree->head))
115 /* in strictsubnets mode do not delete nodes with subnets */
124 put all file descriptors in an fd_set array
125 While we're at it, purge stuff that needs to be removed.
127 static int build_fdset(fd_set *readset, fd_set *writeset) {
128 avl_node_t *node, *next;
135 for(node = connection_tree->head; node; node = next) {
139 if(c->status.remove) {
142 if(!connection_tree->head) {
146 FD_SET(c->socket, readset);
148 if(c->outbuflen > 0 || c->status.connecting) {
149 FD_SET(c->socket, writeset);
152 if(c->socket > max) {
158 for(i = 0; i < listen_sockets; i++) {
159 FD_SET(listen_socket[i].tcp, readset);
161 if(listen_socket[i].tcp > max) {
162 max = listen_socket[i].tcp;
165 FD_SET(listen_socket[i].udp, readset);
167 if(listen_socket[i].udp > max) {
168 max = listen_socket[i].udp;
173 FD_SET(device_fd, readset);
176 if(device_fd > max) {
184 Terminate a connection:
186 - Remove associated edge and tell other connections about it if report = true
187 - Check if we need to retry making an outgoing connection
188 - Deactivate the host
190 void terminate_connection(connection_t *c, bool report) {
191 if(c->status.remove) {
195 ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Closing connection with %s (%s)",
196 c->name, c->hostname);
198 c->status.remove = true;
199 c->status.active = false;
202 c->node->connection = NULL;
206 closesocket(c->socket);
211 logger(LOG_ERR, "Connection to %s (%s) has an edge but node is NULL!", c->name, c->hostname);
212 // And that should never happen.
216 if(report && !tunnelserver) {
217 send_del_edge(everyone, c->edge);
222 /* Run MST and SSSP algorithms */
226 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
228 if(report && !c->node->status.reachable) {
230 e = lookup_edge(c->node, myself);
234 send_del_edge(everyone, e);
242 free_connection_partially(c);
244 /* Check if this was our outgoing connection */
247 c->status.remove = false;
248 do_outgoing_connection(c);
252 /* Clean up dead proxy processes */
254 while(waitpid(-1, NULL, WNOHANG) > 0);
260 Check if the other end is active.
261 If we have sent packets, but didn't receive any,
262 then possibly the other end is dead. We send a
263 PING request over the meta connection. If the other
264 end does not reply in time, we consider them dead
265 and close the connection.
267 static void check_dead_connections(void) {
268 avl_node_t *node, *next;
271 for(node = connection_tree->head; node; node = next) {
275 if(c->last_ping_time + pingtimeout <= now) {
276 if(c->status.active) {
277 if(c->status.pinged) {
278 ifdebug(CONNECTIONS) logger(LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
279 c->name, c->hostname, (long)(now - c->last_ping_time));
280 c->status.timeout = true;
281 terminate_connection(c, true);
282 } else if(c->last_ping_time + pinginterval <= now) {
286 if(c->status.remove) {
287 logger(LOG_WARNING, "Old connection_t for %s (%s) status %04x still lingering, deleting...",
288 c->name, c->hostname, bitfield_to_int(&c->status, sizeof(c->status)));
293 ifdebug(CONNECTIONS) logger(LOG_WARNING, "Timeout from %s (%s) during authentication",
294 c->name, c->hostname);
296 if(c->status.connecting) {
297 c->status.connecting = false;
298 closesocket(c->socket);
299 do_outgoing_connection(c);
301 terminate_connection(c, false);
306 if(c->outbuflen > 0 && c->last_flushed_time + pingtimeout <= now) {
307 if(c->status.active) {
308 ifdebug(CONNECTIONS) logger(LOG_INFO,
309 "%s (%s) could not flush for %ld seconds (%d bytes remaining)",
310 c->name, c->hostname, (long)(now - c->last_flushed_time), c->outbuflen);
311 c->status.timeout = true;
312 terminate_connection(c, true);
319 check all connections to see if anything
320 happened on their sockets
322 static void check_network_activity(fd_set *readset, fd_set *writeset) {
326 socklen_t len = sizeof(result);
328 static int errors = 0;
330 /* check input from kernel */
331 if(device_fd >= 0 && FD_ISSET(device_fd, readset)) {
332 if(devops.read(&packet)) {
336 route(myself, &packet);
339 usleep(errors * 50000);
343 logger(LOG_ERR, "Too many errors from %s, exiting!", device);
349 /* check meta connections */
350 for(node = connection_tree->head; node; node = node->next) {
353 if(c->status.remove) {
357 if(FD_ISSET(c->socket, writeset)) {
358 if(c->status.connecting) {
359 c->status.connecting = false;
360 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
363 finish_connecting(c);
365 ifdebug(CONNECTIONS) logger(LOG_DEBUG,
366 "Error while connecting to %s (%s): %s",
367 c->name, c->hostname, sockstrerror(result));
368 closesocket(c->socket);
369 do_outgoing_connection(c);
375 terminate_connection(c, c->status.active);
380 if(FD_ISSET(c->socket, readset)) {
381 if(!receive_meta(c)) {
382 terminate_connection(c, c->status.active);
388 for(i = 0; i < listen_sockets; i++) {
389 if(FD_ISSET(listen_socket[i].udp, readset)) {
390 handle_incoming_vpn_data(i);
393 if(FD_ISSET(listen_socket[i].tcp, readset)) {
394 handle_new_meta_connection(listen_socket[i].tcp);
400 this is where it all happens...
402 int main_loop(void) {
403 fd_set readset, writeset;
406 sigset_t omask, block_mask;
412 time_t last_ping_check, last_config_check, last_graph_dump;
415 last_ping_check = now;
416 last_config_check = now;
417 last_graph_dump = now;
423 if(lookup_config(config_tree, "GraphDumpFile")) {
427 /* Block SIGHUP & SIGALRM */
428 sigemptyset(&block_mask);
429 sigaddset(&block_mask, SIGHUP);
430 sigaddset(&block_mask, SIGALRM);
431 sigprocmask(SIG_BLOCK, &block_mask, &omask);
438 next_event = last_ping_check + pingtimeout;
440 if(graph_dump && next_event > last_graph_dump + 60) {
441 next_event = last_graph_dump + 60;
444 if((event = peek_next_event()) && next_event > event->time) {
445 next_event = event->time;
448 if(next_event <= now) {
451 tv.tv_sec = next_event - now;
460 maxfd = build_fdset(&readset, &writeset);
463 LeaveCriticalSection(&mutex);
466 r = pselect(maxfd + 1, &readset, &writeset, NULL, &tv, &omask);
468 r = select(maxfd + 1, &readset, &writeset, NULL, &tv);
472 EnterCriticalSection(&mutex);
476 if(!sockwouldblock(sockerrno)) {
477 logger(LOG_ERR, "Error while waiting for input: %s", sockstrerror(sockerrno));
484 check_network_activity(&readset, &writeset);
492 /* Let's check if everybody is still alive */
494 if(last_ping_check + pingtimeout <= now) {
495 check_dead_connections();
496 last_ping_check = now;
498 if(routing_mode == RMODE_SWITCH) {
504 /* Should we regenerate our key? */
506 if(keyexpires <= now) {
510 ifdebug(STATUS) logger(LOG_INFO, "Expiring symmetric keys");
512 for(node = node_tree->head; node; node = node->next) {
522 keyexpires = now + keylifetime;
525 /* Detect ADD_EDGE/DEL_EDGE storms that are caused when
526 * two tinc daemons with the same name are on the VPN.
527 * If so, sleep a while. If this happens multiple times
528 * in a row, sleep longer. */
530 if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
531 logger(LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
532 usleep(sleeptime * 1000000LL);
546 contradicting_add_edge = 0;
547 contradicting_del_edge = 0;
552 logger(LOG_INFO, "Flushing event queue");
555 for(node = connection_tree->head; node; node = node->next) {
556 connection_t *c = node->data;
558 if(c->status.active) {
566 while((event = get_expired_event())) {
567 event->handler(event->data);
573 avl_node_t *node, *next;
581 /* Reread our own configuration file */
583 exit_configuration(&config_tree);
584 init_configuration(&config_tree);
586 if(!read_server_config()) {
587 logger(LOG_ERR, "Unable to reread configuration file, exitting.");
591 /* Cancel non-active outgoing connections */
593 for(node = connection_tree->head; node; node = next) {
599 if(c->status.connecting) {
600 terminate_connection(c, false);
605 /* Wipe list of outgoing connections */
607 for(list_node_t *node = outgoing_list->head; node; node = node->next) {
608 outgoing_t *outgoing = node->data;
610 if(outgoing->event) {
611 event_del(outgoing->event);
615 list_delete_list(outgoing_list);
617 /* Close connections to hosts that have a changed or deleted host config file */
619 for(node = connection_tree->head; node; node = node->next) {
622 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
624 if(stat(fname, &s) || s.st_mtime > last_config_check) {
625 terminate_connection(c, c->status.active);
631 last_config_check = now;
633 /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
638 for(node = subnet_tree->head; node; node = node->next) {
645 for(node = subnet_tree->head; node; node = next) {
649 if(subnet->expires == 1) {
650 send_del_subnet(everyone, subnet);
652 if(subnet->owner->status.reachable) {
653 subnet_update(subnet->owner, subnet, false);
656 subnet_del(subnet->owner, subnet);
657 } else if(subnet->expires == -1) {
660 send_add_subnet(everyone, subnet);
662 if(subnet->owner->status.reachable) {
663 subnet_update(subnet->owner, subnet, true);
669 /* Try to make outgoing connections */
671 try_outgoing_connections();
674 /* Dump graph if wanted every 60 seconds*/
676 if(last_graph_dump + 60 <= now) {
678 last_graph_dump = now;
683 /* Restore SIGHUP & SIGALARM mask */
684 sigprocmask(SIG_SETMASK, &omask, NULL);