/* net.c -- most of the network code Copyright (C) 1998-2005 Ivo Timmermans, 2000-2013 Guus Sliepen 2006 Scott Lamb 2011 Loïc Grenié 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. */ #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 "names.h" #include "net.h" #include "netutl.h" #include "protocol.h" #include "subnet.h" #include "xalloc.h" #ifdef HAVE_RESOLV_H #include #endif int contradicting_add_edge = 0; int contradicting_del_edge = 0; static int sleeptime = 10; time_t last_config_check = 0; static timeout_t pingtimer; static timeout_t periodictimer; /* Purge edges and subnets of unreachable nodes. Use carefully. */ void purge(void) { logger(DEBUG_PROTOCOL, LOG_DEBUG, "Purging unreachable nodes"); /* Remove all edges and subnets owned by unreachable nodes. */ for splay_each(node_t, n, node_tree) { if(!n->status.reachable) { logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Purging node %s (%s)", n->name, n->hostname); for splay_each(subnet_t, s, n->subnet_tree) { send_del_subnet(everyone, s); if(!strictsubnets) subnet_del(n, s); } for splay_each(edge_t, e, n->edge_tree) { if(!tunnelserver) send_del_edge(everyone, e); edge_del(e); } } } /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */ for splay_each(node_t, n, node_tree) { if(!n->status.reachable) { for splay_each(edge_t, e, edge_weight_tree) if(e->to == n) return; if(!autoconnect && (!strictsubnets || !n->subnet_tree->head)) /* in strictsubnets mode do not delete nodes with subnets */ node_del(n); } } } /* 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 */ void terminate_connection(connection_t *c, bool report) { logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Closing connection with %s (%s)", c->name, c->hostname); c->status.active = false; if(c->node && c->node->connection == c) c->node->connection = NULL; if(c->edge) { if(report && !tunnelserver) send_del_edge(everyone, c->edge); edge_del(c->edge); c->edge = NULL; /* Run MST and SSSP algorithms */ 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); } } } outgoing_t *outgoing = c->outgoing; connection_del(c); /* Check if this was our outgoing connection */ if(outgoing) do_outgoing_connection(outgoing); #ifndef HAVE_MINGW /* Clean up dead proxy processes */ while(waitpid(-1, NULL, WNOHANG) > 0); #endif } /* 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. */ static void timeout_handler(void *data) { for list_each(connection_t, c, connection_list) { if(c->status.control) continue; if(c->last_ping_time + pingtimeout <= now.tv_sec) { 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.tv_sec - c->last_ping_time); } else if(c->last_ping_time + pinginterval <= now.tv_sec) { send_ping(c); continue; } else { continue; } } 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); } terminate_connection(c, c->status.active); } } timeout_set(data, &(struct timeval){pingtimeout, rand() % 100000}); } static void periodic_handler(void *data) { /* Check if there are too many contradicting ADD_EDGE and DEL_EDGE messages. This usually only happens when another node has the same Name as this node. If so, sleep for a short while to prevent a storm of contradicting messages. */ 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; } contradicting_add_edge = 0; contradicting_del_edge = 0; /* If AutoConnect is set, check if we need to make or break connections. */ if(autoconnect && node_tree->count > 1) { /* Count number of active connections */ int nc = 0; for list_each(connection_t, c, connection_list) { if(c->status.active && !c->status.control) nc++; } if(nc < 3) { /* Not enough active connections, try to add one. Choose a random node, if we don't have a connection to it, and we are not already trying to make one, create an outgoing connection to this node. */ int r = rand() % node_tree->count; int i = 0; for splay_each(node_t, n, node_tree) { if(i++ != r) continue; if(n->connection) break; bool found = false; for list_each(outgoing_t, outgoing, outgoing_list) { if(!strcmp(outgoing->name, n->name)) { found = true; break; } } if(!found) { logger(DEBUG_CONNECTIONS, LOG_INFO, "Autoconnecting to %s", n->name); outgoing_t *outgoing = xzalloc(sizeof *outgoing); outgoing->name = xstrdup(n->name); list_insert_tail(outgoing_list, outgoing); setup_outgoing_connection(outgoing); } break; } } else if(nc > 3) { /* Too many active connections, try to remove one. Choose a random outgoing connection to a node that has at least one other connection. */ int r = rand() % nc; int i = 0; for list_each(connection_t, c, connection_list) { if(!c->status.active || c->status.control) continue; if(i++ != r) continue; if(!c->outgoing || !c->node || c->node->edge_tree->count < 2) break; logger(DEBUG_CONNECTIONS, LOG_INFO, "Autodisconnecting from %s", c->name); list_delete(outgoing_list, c->outgoing); c->outgoing = NULL; terminate_connection(c, c->status.active); break; } } if(nc >= 3) { /* If we have enough active connections, remove any pending outgoing connections. */ for list_each(outgoing_t, o, outgoing_list) { bool found = false; for list_each(connection_t, c, connection_list) { if(c->outgoing == o) { found = true; break; } } if(!found) { logger(DEBUG_CONNECTIONS, LOG_INFO, "Cancelled outgoing connection to %s", o->name); list_delete_node(outgoing_list, node); } } } } timeout_set(data, &(struct timeval){5, rand() % 100000}); } void handle_meta_connection_data(connection_t *c) { if (!receive_meta(c)) { terminate_connection(c, c->status.active); return; } } #ifndef HAVE_MINGW static void sigterm_handler(void *data) { logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum)); event_exit(); } static void sighup_handler(void *data) { logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum)); reopenlogger(); if(reload_configuration()) exit(1); } static void sigalrm_handler(void *data) { logger(DEBUG_ALWAYS, LOG_NOTICE, "Got %s signal", strsignal(((signal_t *)data)->signum)); #ifdef HAVE_DECL_RES_INIT res_init(); #endif retry(); } #endif int reload_configuration(void) { char *fname = NULL; /* 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."); return EINVAL; } 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) { for splay_each(subnet_t, subnet, subnet_tree) if (subnet->owner) subnet->expires = 1; load_all_subnets(); for splay_each(subnet_t, subnet, subnet_tree) { if (!subnet->owner) continue; 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); } } } else { /* Only read our own subnets back in */ 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); } 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); } } } /* Try to make outgoing connections */ try_outgoing_connections(); /* Close connections to hosts that have a changed or deleted host config file */ 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 = now.tv_sec; return 0; } void retry(void) { /* Reset the reconnection timers for all outgoing connections */ for list_each(outgoing_t, outgoing, outgoing_list) { outgoing->timeout = 0; if(outgoing->ev.cb) timeout_set(&outgoing->ev, &(struct timeval){0, 0}); } /* Check for outgoing connections that are in progress, and reset their ping timers */ for list_each(connection_t, c, connection_list) { if(c->outgoing && !c->node) c->last_ping_time = 0; } /* Kick the ping timeout handler */ timeout_set(&pingtimer, &(struct timeval){0, 0}); } /* this is where it all happens... */ int main_loop(void) { timeout_add(&pingtimer, timeout_handler, &pingtimer, &(struct timeval){pingtimeout, rand() % 100000}); timeout_add(&periodictimer, periodic_handler, &periodictimer, &(struct timeval){pingtimeout, rand() % 100000}); #ifndef HAVE_MINGW signal_t sighup = {0}; signal_t sigterm = {0}; signal_t sigquit = {0}; signal_t sigint = {0}; signal_t sigalrm = {0}; signal_add(&sighup, sighup_handler, &sighup, SIGHUP); signal_add(&sigterm, sigterm_handler, &sigterm, SIGTERM); signal_add(&sigquit, sigterm_handler, &sigquit, SIGQUIT); signal_add(&sigint, sigterm_handler, &sigint, SIGINT); signal_add(&sigalrm, sigalrm_handler, &sigalrm, SIGALRM); #endif if(!event_loop()) { logger(DEBUG_ALWAYS, LOG_ERR, "Error while waiting for input: %s", sockstrerror(sockerrno)); return 1; } #ifndef HAVE_MINGW signal_del(&sighup); signal_del(&sigterm); signal_del(&sigquit); signal_del(&sigint); signal_del(&sigalrm); #endif timeout_del(&periodictimer); timeout_del(&pingtimer); return 0; }