tinc: Add clean sources of 1.1pre10.

[tomato.git] / release / src / router / tinc / src / net.c

/*
    net.c -- most of the network code
    Copyright (C) 1998-2005 Ivo Timmermans,
                  2000-2013 Guus Sliepen <guus@tinc-vpn.org>
                  2006      Scott Lamb <slamb@slamb.org>
                  2011      Loïc Grenié <loic.grenie@gmail.com>

    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"

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 < autoconnect) {
                        /* 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 > autoconnect) {
                        /* 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 >= autoconnect) {
                        /* 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));
        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)
                        subnet->expires = 1;

                load_all_subnets();

                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);
                        }
                }
        } 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", strerror(errno));
                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;
}