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);
223 /* Run MST and SSSP algorithms */
227 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
229 if(report && !c->node->status.reachable) {
231 e = lookup_edge(c->node, myself);
235 send_del_edge(everyone, e);
243 free_connection_partially(c);
245 /* Check if this was our outgoing connection */
248 c->status.remove = false;
249 do_outgoing_connection(c);
253 /* Clean up dead proxy processes */
255 while(waitpid(-1, NULL, WNOHANG) > 0);
261 Check if the other end is active.
262 If we have sent packets, but didn't receive any,
263 then possibly the other end is dead. We send a
264 PING request over the meta connection. If the other
265 end does not reply in time, we consider them dead
266 and close the connection.
268 static void check_dead_connections(void) {
269 avl_node_t *node, *next;
272 for(node = connection_tree->head; node; node = next) {
276 if(c->last_ping_time + pingtimeout <= now) {
277 if(c->status.active) {
278 if(c->status.pinged) {
279 ifdebug(CONNECTIONS) logger(LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
280 c->name, c->hostname, (long)(now - c->last_ping_time));
281 c->status.timeout = true;
282 terminate_connection(c, true);
283 } else if(c->last_ping_time + pinginterval <= now) {
287 if(c->status.remove) {
288 logger(LOG_WARNING, "Old connection_t for %s (%s) status %04x still lingering, deleting...",
289 c->name, c->hostname, bitfield_to_int(&c->status, sizeof(c->status)));
294 ifdebug(CONNECTIONS) logger(LOG_WARNING, "Timeout from %s (%s) during authentication",
295 c->name, c->hostname);
297 if(c->status.connecting) {
298 c->status.connecting = false;
299 closesocket(c->socket);
300 do_outgoing_connection(c);
302 terminate_connection(c, false);
307 if(c->outbuflen > 0 && c->last_flushed_time + pingtimeout <= now) {
308 if(c->status.active) {
309 ifdebug(CONNECTIONS) logger(LOG_INFO,
310 "%s (%s) could not flush for %ld seconds (%d bytes remaining)",
311 c->name, c->hostname, (long)(now - c->last_flushed_time), c->outbuflen);
312 c->status.timeout = true;
313 terminate_connection(c, true);
320 check all connections to see if anything
321 happened on their sockets
323 static void check_network_activity(fd_set *readset, fd_set *writeset) {
327 socklen_t len = sizeof(result);
329 static int errors = 0;
331 /* check input from kernel */
332 if(device_fd >= 0 && FD_ISSET(device_fd, readset)) {
333 if(devops.read(&packet)) {
337 route(myself, &packet);
340 usleep(errors * 50000);
344 logger(LOG_ERR, "Too many errors from %s, exiting!", device);
350 /* check meta connections */
351 for(node = connection_tree->head; node; node = node->next) {
354 if(c->status.remove) {
358 if(FD_ISSET(c->socket, writeset)) {
359 if(c->status.connecting) {
360 c->status.connecting = false;
361 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, (void *)&result, &len);
364 finish_connecting(c);
366 ifdebug(CONNECTIONS) logger(LOG_DEBUG,
367 "Error while connecting to %s (%s): %s",
368 c->name, c->hostname, sockstrerror(result));
369 closesocket(c->socket);
370 do_outgoing_connection(c);
376 terminate_connection(c, c->status.active);
381 if(FD_ISSET(c->socket, readset)) {
382 if(!receive_meta(c)) {
383 terminate_connection(c, c->status.active);
389 for(i = 0; i < listen_sockets; i++) {
390 if(FD_ISSET(listen_socket[i].udp, readset)) {
391 handle_incoming_vpn_data(i);
394 if(FD_ISSET(listen_socket[i].tcp, readset)) {
395 handle_new_meta_connection(listen_socket[i].tcp);
401 this is where it all happens...
403 int main_loop(void) {
404 fd_set readset, writeset;
407 sigset_t omask, block_mask;
413 time_t last_ping_check, last_config_check, last_graph_dump;
416 last_ping_check = now;
417 last_config_check = now;
418 last_graph_dump = now;
424 if(lookup_config(config_tree, "GraphDumpFile")) {
428 /* Block SIGHUP & SIGALRM */
429 sigemptyset(&block_mask);
430 sigaddset(&block_mask, SIGHUP);
431 sigaddset(&block_mask, SIGALRM);
432 sigprocmask(SIG_BLOCK, &block_mask, &omask);
439 next_event = last_ping_check + pingtimeout;
441 if(graph_dump && next_event > last_graph_dump + 60) {
442 next_event = last_graph_dump + 60;
445 if((event = peek_next_event()) && next_event > event->time) {
446 next_event = event->time;
449 if(next_event <= now) {
452 tv.tv_sec = next_event - now;
461 maxfd = build_fdset(&readset, &writeset);
464 LeaveCriticalSection(&mutex);
467 r = pselect(maxfd + 1, &readset, &writeset, NULL, &tv, &omask);
469 r = select(maxfd + 1, &readset, &writeset, NULL, &tv);
473 EnterCriticalSection(&mutex);
477 if(!sockwouldblock(sockerrno)) {
478 logger(LOG_ERR, "Error while waiting for input: %s", sockstrerror(sockerrno));
485 check_network_activity(&readset, &writeset);
493 /* Let's check if everybody is still alive */
495 if(last_ping_check + pingtimeout <= now) {
496 check_dead_connections();
497 last_ping_check = now;
499 if(routing_mode == RMODE_SWITCH) {
505 /* Should we regenerate our key? */
507 if(keyexpires <= now) {
511 ifdebug(STATUS) logger(LOG_INFO, "Expiring symmetric keys");
513 for(node = node_tree->head; node; node = node->next) {
523 keyexpires = now + keylifetime;
526 /* Detect ADD_EDGE/DEL_EDGE storms that are caused when
527 * two tinc daemons with the same name are on the VPN.
528 * If so, sleep a while. If this happens multiple times
529 * in a row, sleep longer. */
531 if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
532 logger(LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
533 usleep(sleeptime * 1000000LL);
547 contradicting_add_edge = 0;
548 contradicting_del_edge = 0;
553 logger(LOG_INFO, "Flushing event queue");
556 for(node = connection_tree->head; node; node = node->next) {
557 connection_t *c = node->data;
559 if(c->status.active) {
567 while((event = get_expired_event())) {
568 event->handler(event->data);
574 avl_node_t *node, *next;
582 /* Reread our own configuration file */
584 exit_configuration(&config_tree);
585 init_configuration(&config_tree);
587 if(!read_server_config()) {
588 logger(LOG_ERR, "Unable to reread configuration file, exitting.");
592 /* Cancel non-active outgoing connections */
594 for(node = connection_tree->head; node; node = next) {
600 if(c->status.connecting) {
601 terminate_connection(c, false);
606 /* Wipe list of outgoing connections */
608 for(list_node_t *node = outgoing_list->head; node; node = node->next) {
609 outgoing_t *outgoing = node->data;
611 if(outgoing->event) {
612 event_del(outgoing->event);
616 list_delete_list(outgoing_list);
618 /* Close connections to hosts that have a changed or deleted host config file */
620 for(node = connection_tree->head; node; node = node->next) {
623 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
625 if(stat(fname, &s) || s.st_mtime > last_config_check) {
626 terminate_connection(c, c->status.active);
632 last_config_check = now;
634 /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
639 for(node = subnet_tree->head; node; node = node->next) {
646 for(node = subnet_tree->head; node; node = next) {
650 if(subnet->expires == 1) {
651 send_del_subnet(everyone, subnet);
653 if(subnet->owner->status.reachable) {
654 subnet_update(subnet->owner, subnet, false);
657 subnet_del(subnet->owner, subnet);
658 } else if(subnet->expires == -1) {
661 send_add_subnet(everyone, subnet);
663 if(subnet->owner->status.reachable) {
664 subnet_update(subnet->owner, subnet, true);
670 /* Try to make outgoing connections */
672 try_outgoing_connections();
675 /* Dump graph if wanted every 60 seconds*/
677 if(last_graph_dump + 60 <= now) {
679 last_graph_dump = now;
684 /* Restore SIGHUP & SIGALARM mask */
685 sigprocmask(SIG_SETMASK, &omask, NULL);