tinc/src/net.c

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/*
net.c -- most of the network code
Copyright (C) 1998-2005 Ivo Timmermans,
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2000-2012 Guus Sliepen <guus@tinc-vpn.org>
2006 Scott Lamb <slamb@slamb.org>
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2011 Loïc Grenié <loic.grenie@gmail.com>
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This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
#include "system.h"
#include "utils.h"
#include "conf.h"
#include "connection.h"
#include "device.h"
#include "graph.h"
#include "logger.h"
#include "meta.h"
#include "net.h"
#include "netutl.h"
#include "process.h"
#include "protocol.h"
#include "subnet.h"
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#include "xalloc.h"
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int contradicting_add_edge = 0;
int contradicting_del_edge = 0;
static int sleeptime = 10;
time_t last_config_check = 0;
/* Purge edges and subnets of unreachable nodes. Use carefully. */
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void purge(void) {
logger(DEBUG_PROTOCOL, LOG_DEBUG, "Purging unreachable nodes");
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/* Remove all edges and subnets owned by unreachable nodes. */
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for splay_each(node_t, n, node_tree) {
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if(!n->status.reachable) {
logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Purging node %s (%s)", n->name, n->hostname);
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for splay_each(subnet_t, s, n->subnet_tree) {
send_del_subnet(everyone, s);
if(!strictsubnets)
subnet_del(n, s);
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}
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for splay_each(edge_t, e, n->edge_tree) {
if(!tunnelserver)
send_del_edge(everyone, e);
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edge_del(e);
}
}
}
/* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
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for splay_each(node_t, n, node_tree) {
if(!n->status.reachable) {
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for splay_each(edge_t, e, edge_weight_tree)
if(e->to == n)
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return;
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if(!strictsubnets || !n->subnet_tree->head)
/* in strictsubnets mode do not delete nodes with subnets */
node_del(n);
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}
}
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}
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/*
Terminate a connection:
- Mark it as inactive
- Remove the edge representing this connection
- Kill it with fire
- Check if we need to retry making an outgoing connection
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*/
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void terminate_connection(connection_t *c, bool report) {
logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)", c->name, c->hostname);
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c->status.active = false;
if(c->node && c->node->connection == c)
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c->node->connection = NULL;
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if(c->edge) {
if(report && !tunnelserver)
send_del_edge(everyone, c->edge);
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edge_del(c->edge);
c->edge = NULL;
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/* Run MST and SSSP algorithms */
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graph();
/* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
if(report && !c->node->status.reachable) {
edge_t *e;
e = lookup_edge(c->node, myself);
if(e) {
if(!tunnelserver)
send_del_edge(everyone, e);
edge_del(e);
}
}
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}
outgoing_t *outgoing = c->outgoing;
connection_del(c);
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/* Check if this was our outgoing connection */
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if(outgoing)
do_outgoing_connection(outgoing);
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}
/*
Check if the other end is active.
If we have sent packets, but didn't receive any,
then possibly the other end is dead. We send a
PING request over the meta connection. If the other
end does not reply in time, we consider them dead
and close the connection.
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*/
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static void timeout_handler(int fd, short events, void *event) {
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time_t now = time(NULL);
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for list_each(connection_t, c, connection_list) {
if(c->status.control)
continue;
if(c->last_ping_time + pingtimeout <= now) {
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if(c->status.active) {
if(c->status.pinged) {
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);
} else if(c->last_ping_time + pinginterval <= now) {
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send_ping(c);
continue;
} else {
continue;
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}
} else {
if(c->status.connecting)
logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
else
logger(DEBUG_CONNECTIONS, LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
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}
terminate_connection(c, c->status.active);
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}
}
if(contradicting_del_edge > 100 && contradicting_add_edge > 100) {
logger(DEBUG_ALWAYS, LOG_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", sleeptime);
usleep(sleeptime * 1000000LL);
sleeptime *= 2;
if(sleeptime < 0)
sleeptime = 3600;
} else {
sleeptime /= 2;
if(sleeptime < 10)
sleeptime = 10;
}
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contradicting_add_edge = 0;
contradicting_del_edge = 0;
event_add(event, &(struct timeval){pingtimeout, 0});
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}
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void handle_meta_connection_data(int fd, short events, void *data) {
connection_t *c = data;
int result;
socklen_t len = sizeof result;
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if(c->status.connecting) {
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c->status.connecting = false;
getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
if(!result)
finish_connecting(c);
else {
logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Error while connecting to %s (%s): %s", c->name, c->hostname, sockstrerror(result));
terminate_connection(c, false);
return;
}
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}
if (!receive_meta(c)) {
terminate_connection(c, c->status.active);
return;
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}
}
static void sigterm_handler(int signal, short events, void *data) {
logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
event_loopexit(NULL);
}
static void sighup_handler(int signal, short events, void *data) {
logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
reopenlogger();
reload_configuration();
}
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static void sigalrm_handler(int signal, short events, void *data) {
logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(signal));
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retry();
}
int reload_configuration(void) {
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char *fname;
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/* Reread our own configuration file */
exit_configuration(&config_tree);
init_configuration(&config_tree);
if(!read_server_config()) {
logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reread configuration file, exitting.");
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event_loopexit(NULL);
return EINVAL;
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}
read_config_options(config_tree, NULL);
xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, myself->name);
read_config_file(config_tree, fname);
free(fname);
/* Parse some options that are allowed to be changed while tinc is running */
setup_myself_reloadable();
/* If StrictSubnet is set, expire deleted Subnets and read new ones in */
if(strictsubnets) {
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for splay_each(subnet_t, subnet, subnet_tree)
subnet->expires = 1;
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load_all_subnets();
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for splay_each(subnet_t, subnet, subnet_tree) {
if(subnet->expires == 1) {
send_del_subnet(everyone, subnet);
if(subnet->owner->status.reachable)
subnet_update(subnet->owner, subnet, false);
subnet_del(subnet->owner, subnet);
} else if(subnet->expires == -1) {
subnet->expires = 0;
} else {
send_add_subnet(everyone, subnet);
if(subnet->owner->status.reachable)
subnet_update(subnet->owner, subnet, true);
}
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}
} else { /* Only read our own subnets back in */
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for splay_each(subnet_t, subnet, myself->subnet_tree)
if(!subnet->expires)
subnet->expires = 1;
config_t *cfg = lookup_config(config_tree, "Subnet");
while(cfg) {
subnet_t *subnet, *s2;
if(!get_config_subnet(cfg, &subnet))
continue;
if((s2 = lookup_subnet(myself, subnet))) {
if(s2->expires == 1)
s2->expires = 0;
free_subnet(subnet);
} else {
subnet_add(myself, subnet);
send_add_subnet(everyone, subnet);
subnet_update(myself, subnet, true);
}
cfg = lookup_config_next(config_tree, cfg);
}
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for splay_each(subnet_t, subnet, myself->subnet_tree) {
if(subnet->expires == 1) {
send_del_subnet(everyone, subnet);
subnet_update(myself, subnet, false);
subnet_del(myself, subnet);
}
}
}
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/* Try to make outgoing connections */
try_outgoing_connections();
/* Close connections to hosts that have a changed or deleted host config file */
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for list_each(connection_t, c, connection_list) {
if(c->status.control)
continue;
xasprintf(&fname, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
struct stat s;
if(stat(fname, &s) || s.st_mtime > last_config_check) {
logger(DEBUG_CONNECTIONS, LOG_INFO, "Host config file of %s has been changed", c->name);
terminate_connection(c, c->status.active);
}
free(fname);
}
last_config_check = time(NULL);
return 0;
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}
void retry(void) {
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for list_each(connection_t, c, connection_list) {
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if(c->outgoing && !c->node) {
if(timeout_initialized(&c->outgoing->ev))
event_del(&c->outgoing->ev);
if(c->status.connecting)
close(c->socket);
c->outgoing->timeout = 0;
terminate_connection(c, c->status.active);
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}
}
}
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/*
this is where it all happens...
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*/
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int main_loop(void) {
struct event timeout_event;
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timeout_set(&timeout_event, timeout_handler, &timeout_event);
event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
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#ifndef HAVE_MINGW
struct event sighup_event;
struct event sigterm_event;
struct event sigquit_event;
struct event sigalrm_event;
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signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
signal_add(&sighup_event, NULL);
signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
signal_add(&sigterm_event, NULL);
signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
signal_add(&sigquit_event, NULL);
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signal_set(&sigalrm_event, SIGALRM, sigalrm_handler, NULL);
signal_add(&sigalrm_event, NULL);
#endif
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if(event_loop(0) < 0) {
logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", strerror(errno));
return 1;
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}
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#ifndef HAVE_MINGW
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signal_del(&sighup_event);
signal_del(&sigterm_event);
signal_del(&sigquit_event);
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signal_del(&sigalrm_event);
#endif
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event_del(&timeout_event);
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return 0;
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}