2 net.c -- most of the network code
3 Copyright (C) 1998-2005 Ivo Timmermans,
4 2000-2013 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"
43 int contradicting_add_edge = 0;
44 int contradicting_del_edge = 0;
45 static int sleeptime = 10;
46 time_t last_config_check = 0;
47 static timeout_t pingtimer;
48 static timeout_t periodictimer;
50 /* Purge edges and subnets of unreachable nodes. Use carefully. */
53 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Purging unreachable nodes");
55 /* Remove all edges and subnets owned by unreachable nodes. */
57 for splay_each(node_t, n, node_tree) {
58 if(!n->status.reachable) {
59 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Purging node %s (%s)", n->name, n->hostname);
61 for splay_each(subnet_t, s, n->subnet_tree) {
62 send_del_subnet(everyone, s);
67 for splay_each(edge_t, e, n->edge_tree) {
69 send_del_edge(everyone, e);
75 /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
77 for splay_each(node_t, n, node_tree) {
78 if(!n->status.reachable) {
79 for splay_each(edge_t, e, edge_weight_tree)
83 if(!autoconnect && (!strictsubnets || !n->subnet_tree->head))
84 /* in strictsubnets mode do not delete nodes with subnets */
91 Terminate a connection:
93 - Remove the edge representing this connection
95 - Check if we need to retry making an outgoing connection
97 void terminate_connection(connection_t *c, bool report) {
98 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)", c->name, c->hostname);
100 c->status.active = false;
102 if(c->node && c->node->connection == c)
103 c->node->connection = NULL;
106 if(report && !tunnelserver)
107 send_del_edge(everyone, c->edge);
112 /* Run MST and SSSP algorithms */
116 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
118 if(report && !c->node->status.reachable) {
120 e = lookup_edge(c->node, myself);
123 send_del_edge(everyone, e);
129 outgoing_t *outgoing = c->outgoing;
132 /* Check if this was our outgoing connection */
135 do_outgoing_connection(outgoing);
138 /* Clean up dead proxy processes */
140 while(waitpid(-1, NULL, WNOHANG) > 0);
145 Check if the other end is active.
146 If we have sent packets, but didn't receive any,
147 then possibly the other end is dead. We send a
148 PING request over the meta connection. If the other
149 end does not reply in time, we consider them dead
150 and close the connection.
152 static void timeout_handler(void *data) {
153 for list_each(connection_t, c, connection_list) {
154 if(c->status.control)
157 if(c->last_ping_time + pingtimeout <= now.tv_sec) {
158 if(c->status.active) {
159 if(c->status.pinged) {
160 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);
161 } else if(c->last_ping_time + pinginterval <= now.tv_sec) {
168 if(c->status.connecting)
169 logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
171 logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
173 terminate_connection(c, c->status.active);
177 timeout_set(data, &(struct timeval){pingtimeout, rand() % 100000});
180 static void periodic_handler(void *data) {
181 /* Check if there are too many contradicting ADD_EDGE and DEL_EDGE messages.
182 This usually only happens when another node has the same Name as this node.
183 If so, sleep for a short while to prevent a storm of contradicting messages.
186 if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
187 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
188 usleep(sleeptime * 1000000LL);
198 contradicting_add_edge = 0;
199 contradicting_del_edge = 0;
201 /* If AutoConnect is set, check if we need to make or break connections. */
203 if(autoconnect && node_tree->count > 1) {
204 /* Count number of active connections */
206 for list_each(connection_t, c, connection_list) {
207 if(c->status.active && !c->status.control)
212 /* Not enough active connections, try to add one.
213 Choose a random node, if we don't have a connection to it,
214 and we are not already trying to make one, create an
215 outgoing connection to this node.
217 int r = rand() % node_tree->count;
220 for splay_each(node_t, n, node_tree) {
229 for list_each(outgoing_t, outgoing, outgoing_list) {
230 if(!strcmp(outgoing->name, n->name)) {
237 logger(DEBUG_CONNECTIONS, LOG_INFO, "Autoconnecting to %s", n->name);
238 outgoing_t *outgoing = xzalloc(sizeof *outgoing);
239 outgoing->name = xstrdup(n->name);
240 list_insert_tail(outgoing_list, outgoing);
241 setup_outgoing_connection(outgoing);
246 /* Too many active connections, try to remove one.
247 Choose a random outgoing connection to a node
248 that has at least one other connection.
253 for list_each(connection_t, c, connection_list) {
254 if(!c->status.active || c->status.control)
260 if(!c->outgoing || !c->node || c->node->edge_tree->count < 2)
263 logger(DEBUG_CONNECTIONS, LOG_INFO, "Autodisconnecting from %s", c->name);
264 list_delete(outgoing_list, c->outgoing);
266 terminate_connection(c, c->status.active);
272 /* If we have enough active connections,
273 remove any pending outgoing connections.
275 for list_each(outgoing_t, o, outgoing_list) {
277 for list_each(connection_t, c, connection_list) {
278 if(c->outgoing == o) {
284 logger(DEBUG_CONNECTIONS, LOG_INFO, "Cancelled outgoing connection to %s", o->name);
285 list_delete_node(outgoing_list, node);
291 timeout_set(data, &(struct timeval){5, rand() % 100000});
294 void handle_meta_connection_data(connection_t *c) {
295 if (!receive_meta(c)) {
296 terminate_connection(c, c->status.active);
302 static void sigterm_handler(void *data) {
303 logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
307 static void sighup_handler(void *data) {
308 logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
310 if(reload_configuration())
314 static void sigalrm_handler(void *data) {
315 logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum));
316 #ifdef HAVE_DECL_RES_INIT
323 int reload_configuration(void) {
326 /* Reread our own configuration file */
328 exit_configuration(&config_tree);
329 init_configuration(&config_tree);
331 if(!read_server_config()) {
332 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file.");
336 read_config_options(config_tree, NULL);
338 xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, myself->name);
339 read_config_file(config_tree, fname);
342 /* Parse some options that are allowed to be changed while tinc is running */
344 setup_myself_reloadable();
346 /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
349 for splay_each(subnet_t, subnet, subnet_tree)
354 for splay_each(subnet_t, subnet, subnet_tree) {
355 if(subnet->expires == 1) {
356 send_del_subnet(everyone, subnet);
357 if(subnet->owner->status.reachable)
358 subnet_update(subnet->owner, subnet, false);
359 subnet_del(subnet->owner, subnet);
360 } else if(subnet->expires == -1) {
363 send_add_subnet(everyone, subnet);
364 if(subnet->owner->status.reachable)
365 subnet_update(subnet->owner, subnet, true);
368 } else { /* Only read our own subnets back in */
369 for splay_each(subnet_t, subnet, myself->subnet_tree)
373 config_t *cfg = lookup_config(config_tree, "Subnet");
376 subnet_t *subnet, *s2;
378 if(!get_config_subnet(cfg, &subnet))
381 if((s2 = lookup_subnet(myself, subnet))) {
387 subnet_add(myself, subnet);
388 send_add_subnet(everyone, subnet);
389 subnet_update(myself, subnet, true);
392 cfg = lookup_config_next(config_tree, cfg);
395 for splay_each(subnet_t, subnet, myself->subnet_tree) {
396 if(subnet->expires == 1) {
397 send_del_subnet(everyone, subnet);
398 subnet_update(myself, subnet, false);
399 subnet_del(myself, subnet);
404 /* Try to make outgoing connections */
406 try_outgoing_connections();
408 /* Close connections to hosts that have a changed or deleted host config file */
410 for list_each(connection_t, c, connection_list) {
411 if(c->status.control)
414 xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
416 if(stat(fname, &s) || s.st_mtime > last_config_check) {
417 logger(DEBUG_CONNECTIONS, LOG_INFO, "Host config file of %s has been changed", c->name);
418 terminate_connection(c, c->status.active);
423 last_config_check = now.tv_sec;
429 /* Reset the reconnection timers for all outgoing connections */
430 for list_each(outgoing_t, outgoing, outgoing_list) {
431 outgoing->timeout = 0;
433 timeout_set(&outgoing->ev, &(struct timeval){0, 0});
436 /* Check for outgoing connections that are in progress, and reset their ping timers */
437 for list_each(connection_t, c, connection_list) {
438 if(c->outgoing && !c->node)
439 c->last_ping_time = 0;
442 /* Kick the ping timeout handler */
443 timeout_set(&pingtimer, &(struct timeval){0, 0});
447 this is where it all happens...
449 int main_loop(void) {
450 timeout_add(&pingtimer, timeout_handler, &pingtimer, &(struct timeval){pingtimeout, rand() % 100000});
451 timeout_add(&periodictimer, periodic_handler, &periodictimer, &(struct timeval){pingtimeout, rand() % 100000});
454 signal_t sighup = {0};
455 signal_t sigterm = {0};
456 signal_t sigquit = {0};
457 signal_t sigint = {0};
458 signal_t sigalrm = {0};
460 signal_add(&sighup, sighup_handler, &sighup, SIGHUP);
461 signal_add(&sigterm, sigterm_handler, &sigterm, SIGTERM);
462 signal_add(&sigquit, sigterm_handler, &sigquit, SIGQUIT);
463 signal_add(&sigint, sigterm_handler, &sigint, SIGINT);
464 signal_add(&sigalrm, sigalrm_handler, &sigalrm, SIGALRM);
468 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", sockstrerror(sockerrno));
474 signal_del(&sigterm);
475 signal_del(&sigquit);
477 signal_del(&sigalrm);
480 timeout_del(&periodictimer);
481 timeout_del(&pingtimer);