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.
27 #include "connection.h"
39 int contradicting_add_edge = 0;
40 int contradicting_del_edge = 0;
41 static int sleeptime = 10;
42 time_t last_config_check = 0;
43 static timeout_t pingtimer;
44 static timeout_t periodictimer;
46 /* Purge edges and subnets of unreachable nodes. Use carefully. */
49 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Purging unreachable nodes");
51 /* Remove all edges and subnets owned by unreachable nodes. */
53 for splay_each(node_t, n, node_tree) {
54 if(!n->status.reachable) {
55 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Purging node %s (%s)", n->name, n->hostname);
57 for splay_each(subnet_t, s, n->subnet_tree) {
58 send_del_subnet(everyone, s);
63 for splay_each(edge_t, e, n->edge_tree) {
65 send_del_edge(everyone, e);
71 /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
73 for splay_each(node_t, n, node_tree) {
74 if(!n->status.reachable) {
75 for splay_each(edge_t, e, edge_weight_tree)
79 if(!autoconnect && (!strictsubnets || !n->subnet_tree->head))
80 /* in strictsubnets mode do not delete nodes with subnets */
87 Terminate a connection:
89 - Remove the edge representing this connection
91 - Check if we need to retry making an outgoing connection
93 void terminate_connection(connection_t *c, bool report) {
94 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)", c->name, c->hostname);
96 if(c->node && c->node->connection == c)
97 c->node->connection = NULL;
100 if(report && !tunnelserver)
101 send_del_edge(everyone, c->edge);
106 /* Run MST and SSSP algorithms */
110 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
112 if(report && !c->node->status.reachable) {
114 e = lookup_edge(c->node, myself);
117 send_del_edge(everyone, e);
123 outgoing_t *outgoing = c->outgoing;
126 /* Check if this was our outgoing connection */
129 do_outgoing_connection(outgoing);
132 /* Clean up dead proxy processes */
134 while(waitpid(-1, NULL, WNOHANG) > 0);
139 Check if the other end is active.
140 If we have sent packets, but didn't receive any,
141 then possibly the other end is dead. We send a
142 PING request over the meta connection. If the other
143 end does not reply in time, we consider them dead
144 and close the connection.
146 static void timeout_handler(void *data) {
147 for list_each(connection_t, c, connection_list) {
148 if(c->status.control)
151 if(c->last_ping_time + pingtimeout <= now.tv_sec) {
153 try_tx(c->node, false);
154 if(c->status.pinged) {
155 logger(DEBUG_CONNECTIONS, LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds", c->name, c->hostname, (long)now.tv_sec - c->last_ping_time);
156 } else if(c->last_ping_time + pinginterval <= now.tv_sec) {
163 if(c->status.connecting)
164 logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
166 logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
168 terminate_connection(c, c->edge);
173 timeout_set(data, &(struct timeval){1, rand() % 100000});
176 static void periodic_handler(void *data) {
177 /* Check if there are too many contradicting ADD_EDGE and DEL_EDGE messages.
178 This usually only happens when another node has the same Name as this node.
179 If so, sleep for a short while to prevent a storm of contradicting messages.
182 if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
183 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
184 nanosleep(&(struct timespec){sleeptime, 0}, NULL);
194 contradicting_add_edge = 0;
195 contradicting_del_edge = 0;
197 /* If AutoConnect is set, check if we need to make or break connections. */
199 if(autoconnect && node_tree->count > 1) {
200 /* Count number of active connections */
202 for list_each(connection_t, c, connection_list) {
208 /* Not enough active connections, try to add one.
209 Choose a random node, if we don't have a connection to it,
210 and we are not already trying to make one, create an
211 outgoing connection to this node.
213 int r = rand() % node_tree->count;
216 for splay_each(node_t, n, node_tree) {
225 for list_each(outgoing_t, outgoing, outgoing_list) {
226 if(!strcmp(outgoing->name, n->name)) {
233 logger(DEBUG_CONNECTIONS, LOG_INFO, "Autoconnecting to %s", n->name);
234 outgoing_t *outgoing = xzalloc(sizeof *outgoing);
235 outgoing->name = xstrdup(n->name);
236 list_insert_tail(outgoing_list, outgoing);
237 setup_outgoing_connection(outgoing);
242 /* Too many active connections, try to remove one.
243 Choose a random outgoing connection to a node
244 that has at least one other connection.
249 for list_each(connection_t, c, connection_list) {
256 if(!c->outgoing || !c->node || c->node->edge_tree->count < 2)
259 logger(DEBUG_CONNECTIONS, LOG_INFO, "Autodisconnecting from %s", c->name);
260 list_delete(outgoing_list, c->outgoing);
262 terminate_connection(c, c->edge);
268 /* If we have enough active connections,
269 remove any pending outgoing connections.
271 for list_each(outgoing_t, o, outgoing_list) {
273 for list_each(connection_t, c, connection_list) {
274 if(c->outgoing == o) {
280 logger(DEBUG_CONNECTIONS, LOG_INFO, "Cancelled outgoing connection to %s", o->name);
281 list_delete_node(outgoing_list, node);
287 timeout_set(data, &(struct timeval){5, rand() % 100000});
290 void handle_meta_connection_data(connection_t *c) {
291 if (!receive_meta(c)) {
292 terminate_connection(c, c->edge);
298 static void sigterm_handler(void *data) {
299 logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
303 static void sighup_handler(void *data) {
304 logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
306 if(reload_configuration())
310 static void sigalrm_handler(void *data) {
311 logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
316 int reload_configuration(void) {
317 char fname[PATH_MAX];
319 /* Reread our own configuration file */
321 exit_configuration(&config_tree);
322 init_configuration(&config_tree);
324 if(!read_server_config()) {
325 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file.");
329 read_config_options(config_tree, NULL);
331 snprintf(fname, sizeof fname, "%s" SLASH "hosts" SLASH "%s", confbase, myself->name);
332 read_config_file(config_tree, fname);
334 /* Parse some options that are allowed to be changed while tinc is running */
336 setup_myself_reloadable();
338 /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
341 for splay_each(subnet_t, subnet, subnet_tree)
347 for splay_each(subnet_t, subnet, subnet_tree) {
350 if(subnet->expires == 1) {
351 send_del_subnet(everyone, subnet);
352 if(subnet->owner->status.reachable)
353 subnet_update(subnet->owner, subnet, false);
354 subnet_del(subnet->owner, subnet);
355 } else if(subnet->expires == -1) {
358 send_add_subnet(everyone, subnet);
359 if(subnet->owner->status.reachable)
360 subnet_update(subnet->owner, subnet, true);
363 } else { /* Only read our own subnets back in */
364 for splay_each(subnet_t, subnet, myself->subnet_tree)
368 config_t *cfg = lookup_config(config_tree, "Subnet");
371 subnet_t *subnet, *s2;
373 if(!get_config_subnet(cfg, &subnet))
376 if((s2 = lookup_subnet(myself, subnet))) {
382 subnet_add(myself, subnet);
383 send_add_subnet(everyone, subnet);
384 subnet_update(myself, subnet, true);
387 cfg = lookup_config_next(config_tree, cfg);
390 for splay_each(subnet_t, subnet, myself->subnet_tree) {
391 if(subnet->expires == 1) {
392 send_del_subnet(everyone, subnet);
393 subnet_update(myself, subnet, false);
394 subnet_del(myself, subnet);
399 /* Try to make outgoing connections */
401 try_outgoing_connections();
403 /* Close connections to hosts that have a changed or deleted host config file */
405 for list_each(connection_t, c, connection_list) {
406 if(c->status.control)
409 snprintf(fname, sizeof fname, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
411 if(stat(fname, &s) || s.st_mtime > last_config_check) {
412 logger(DEBUG_CONNECTIONS, LOG_INFO, "Host config file of %s has been changed", c->name);
413 terminate_connection(c, c->edge);
417 last_config_check = now.tv_sec;
423 /* Reset the reconnection timers for all outgoing connections */
424 for list_each(outgoing_t, outgoing, outgoing_list) {
425 outgoing->timeout = 0;
427 timeout_set(&outgoing->ev, &(struct timeval){0, 0});
430 /* Check for outgoing connections that are in progress, and reset their ping timers */
431 for list_each(connection_t, c, connection_list) {
432 if(c->outgoing && !c->node)
433 c->last_ping_time = 0;
436 /* Kick the ping timeout handler */
437 timeout_set(&pingtimer, &(struct timeval){0, 0});
441 this is where it all happens...
443 int main_loop(void) {
444 timeout_add(&pingtimer, timeout_handler, &pingtimer, &(struct timeval){pingtimeout, rand() % 100000});
445 timeout_add(&periodictimer, periodic_handler, &periodictimer, &(struct timeval){pingtimeout, rand() % 100000});
448 signal_t sighup = {0};
449 signal_t sigterm = {0};
450 signal_t sigquit = {0};
451 signal_t sigint = {0};
452 signal_t sigalrm = {0};
454 signal_add(&sighup, sighup_handler, &sighup, SIGHUP);
455 signal_add(&sigterm, sigterm_handler, &sigterm, SIGTERM);
456 signal_add(&sigquit, sigterm_handler, &sigquit, SIGQUIT);
457 signal_add(&sigint, sigterm_handler, &sigint, SIGINT);
458 signal_add(&sigalrm, sigalrm_handler, &sigalrm, SIGALRM);
462 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", sockstrerror(sockerrno));
468 signal_del(&sigterm);
469 signal_del(&sigquit);
471 signal_del(&sigalrm);
474 timeout_del(&periodictimer);
475 timeout_del(&pingtimer);