2 net.c -- most of the network code
3 Copyright (C) 1998-2005 Ivo Timmermans,
4 2000-2012 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;
44 /* Purge edges and subnets of unreachable nodes. Use carefully. */
47 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Purging unreachable nodes");
49 /* Remove all edges and subnets owned by unreachable nodes. */
51 for splay_each(node_t, n, node_tree) {
52 if(!n->status.reachable) {
53 logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Purging node %s (%s)", n->name, n->hostname);
55 for splay_each(subnet_t, s, n->subnet_tree) {
56 send_del_subnet(everyone, s);
61 for splay_each(edge_t, e, n->edge_tree) {
63 send_del_edge(everyone, e);
69 /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
71 for splay_each(node_t, n, node_tree) {
72 if(!n->status.reachable) {
73 for splay_each(edge_t, e, edge_weight_tree)
77 if(!autoconnect && (!strictsubnets || !n->subnet_tree->head))
78 /* in strictsubnets mode do not delete nodes with subnets */
85 Terminate a connection:
87 - Remove the edge representing this connection
89 - Check if we need to retry making an outgoing connection
91 void terminate_connection(connection_t *c, bool report) {
92 logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)", c->name, c->hostname);
94 c->status.active = false;
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);
133 Check if the other end is active.
134 If we have sent packets, but didn't receive any,
135 then possibly the other end is dead. We send a
136 PING request over the meta connection. If the other
137 end does not reply in time, we consider them dead
138 and close the connection.
140 static void timeout_handler(int fd, short events, void *event) {
141 time_t now = time(NULL);
143 for list_each(connection_t, c, connection_list) {
144 if(c->status.control)
147 if(c->last_ping_time + pingtimeout <= now) {
148 if(c->status.active) {
149 if(c->status.pinged) {
150 logger(DEBUG_CONNECTIONS, LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds", c->name, c->hostname, (long)now - c->last_ping_time);
151 } else if(c->last_ping_time + pinginterval <= now) {
158 if(c->status.connecting)
159 logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
161 logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
163 terminate_connection(c, c->status.active);
167 event_add(event, &(struct timeval){pingtimeout, 0});
170 static void periodic_handler(int fd, short events, void *event) {
171 /* Check if there are too many contradicting ADD_EDGE and DEL_EDGE messages.
172 This usually only happens when another node has the same Name as this node.
173 If so, sleep for a short while to prevent a storm of contradicting messages.
176 if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
177 logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
178 usleep(sleeptime * 1000000LL);
188 contradicting_add_edge = 0;
189 contradicting_del_edge = 0;
191 /* If AutoConnect is set, check if we need to make or break connections. */
193 if(autoconnect && node_tree->count > 1) {
194 /* Count number of active connections */
196 for list_each(connection_t, c, connection_list) {
197 if(c->status.active && !c->status.control)
201 if(nc < autoconnect) {
202 /* Not enough active connections, try to add one.
203 Choose a random node, if we don't have a connection to it,
204 and we are not already trying to make one, create an
205 outgoing connection to this node.
207 int r = rand() % node_tree->count;
210 for splay_each(node_t, n, node_tree) {
219 for list_each(outgoing_t, outgoing, outgoing_list) {
220 if(!strcmp(outgoing->name, n->name)) {
227 logger(DEBUG_CONNECTIONS, LOG_INFO, "Autoconnecting to %s", n->name);
228 outgoing_t *outgoing = xmalloc_and_zero(sizeof *outgoing);
229 outgoing->name = xstrdup(n->name);
230 list_insert_tail(outgoing_list, outgoing);
231 setup_outgoing_connection(outgoing);
235 } else if(nc > autoconnect) {
236 /* Too many active connections, try to remove one.
237 Choose a random outgoing connection to a node
238 that has at least one other connection.
243 for list_each(connection_t, c, connection_list) {
244 if(!c->status.active || c->status.control)
250 if(!c->outgoing || !c->node || c->node->edge_tree->count < 2)
253 logger(DEBUG_CONNECTIONS, LOG_INFO, "Autodisconnecting from %s", c->name);
254 list_delete(outgoing_list, c->outgoing);
256 terminate_connection(c, c->status.active);
261 if(nc >= autoconnect) {
262 /* If we have enough active connections,
263 remove any pending outgoing connections.
265 for list_each(outgoing_t, o, outgoing_list) {
267 for list_each(connection_t, c, connection_list) {
268 if(c->outgoing == o) {
274 logger(DEBUG_CONNECTIONS, LOG_INFO, "Cancelled outgoing connection to %s", o->name);
275 list_delete_node(outgoing_list, node);
281 event_add(event, &(struct timeval){5, 0});
284 void handle_meta_connection_data(int fd, short events, void *data) {
285 connection_t *c = data;
287 socklen_t len = sizeof result;
289 if(c->status.connecting) {
290 c->status.connecting = false;
292 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
295 finish_connecting(c);
297 logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(result));
298 terminate_connection(c, false);
303 if (!receive_meta(c)) {
304 terminate_connection(c, c->status.active);
309 static void sigterm_handler(int signal, short events, void *data) {
310 logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
311 event_loopexit(NULL);
314 static void sighup_handler(int signal, short events, void *data) {
315 logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
317 reload_configuration();
320 static void sigalrm_handler(int signal, short events, void *data) {
321 logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
325 int reload_configuration(void) {
328 /* Reread our own configuration file */
330 exit_configuration(&config_tree);
331 init_configuration(&config_tree);
333 if(!read_server_config()) {
334 logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file, exitting.");
335 event_loopexit(NULL);
339 read_config_options(config_tree, NULL);
341 xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, myself->name);
342 read_config_file(config_tree, fname);
345 /* Parse some options that are allowed to be changed while tinc is running */
347 setup_myself_reloadable();
349 /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
352 for splay_each(subnet_t, subnet, subnet_tree)
357 for splay_each(subnet_t, subnet, subnet_tree) {
358 if(subnet->expires == 1) {
359 send_del_subnet(everyone, subnet);
360 if(subnet->owner->status.reachable)
361 subnet_update(subnet->owner, subnet, false);
362 subnet_del(subnet->owner, subnet);
363 } else if(subnet->expires == -1) {
366 send_add_subnet(everyone, subnet);
367 if(subnet->owner->status.reachable)
368 subnet_update(subnet->owner, subnet, true);
371 } else { /* Only read our own subnets back in */
372 for splay_each(subnet_t, subnet, myself->subnet_tree)
376 config_t *cfg = lookup_config(config_tree, "Subnet");
379 subnet_t *subnet, *s2;
381 if(!get_config_subnet(cfg, &subnet))
384 if((s2 = lookup_subnet(myself, subnet))) {
390 subnet_add(myself, subnet);
391 send_add_subnet(everyone, subnet);
392 subnet_update(myself, subnet, true);
395 cfg = lookup_config_next(config_tree, cfg);
398 for splay_each(subnet_t, subnet, myself->subnet_tree) {
399 if(subnet->expires == 1) {
400 send_del_subnet(everyone, subnet);
401 subnet_update(myself, subnet, false);
402 subnet_del(myself, subnet);
407 /* Try to make outgoing connections */
409 try_outgoing_connections();
411 /* Close connections to hosts that have a changed or deleted host config file */
413 for list_each(connection_t, c, connection_list) {
414 if(c->status.control)
417 xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
419 if(stat(fname, &s) || s.st_mtime > last_config_check) {
420 logger(DEBUG_CONNECTIONS, LOG_INFO, "Host config file of %s has been changed", c->name);
421 terminate_connection(c, c->status.active);
426 last_config_check = time(NULL);
432 for list_each(connection_t, c, connection_list) {
433 if(c->outgoing && !c->node) {
434 if(timeout_initialized(&c->outgoing->ev))
435 event_del(&c->outgoing->ev);
436 if(c->status.connecting)
438 c->outgoing->timeout = 0;
439 terminate_connection(c, c->status.active);
445 this is where it all happens...
447 int main_loop(void) {
448 struct event timeout_event;
449 struct event periodic_event;
451 timeout_set(&timeout_event, timeout_handler, &timeout_event);
452 event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
454 timeout_set(&periodic_event, periodic_handler, &periodic_event);
455 event_add(&periodic_event, &(struct timeval){5, 0});
458 struct event sighup_event;
459 struct event sigterm_event;
460 struct event sigquit_event;
461 struct event sigalrm_event;
463 signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
464 signal_add(&sighup_event, NULL);
465 signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
466 signal_add(&sigterm_event, NULL);
467 signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
468 signal_add(&sigquit_event, NULL);
469 signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
470 signal_add(&sigalrm_event, NULL);
473 if(event_loop(0) < 0) {
474 logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
479 signal_del(&sighup_event);
480 signal_del(&sigterm_event);
481 signal_del(&sigquit_event);
482 signal_del(&sigalrm_event);
485 event_del(&timeout_event);