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tinc/src/net.c
Guus Sliepen 1eedf54681 - Use only one socket for all UDP traffic (for compatibility) 
- Write pidfile again after detaching
- Check OS (for handling FreeBSD/Solaris tun/tap stuff)
2000-11-25 13:33:33 +00:00

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/*
net.c -- most of the network code
Copyright (C) 1998,1999,2000 Ivo Timmermans <itimmermans@bigfoot.com>,
2000 Guus Sliepen <guus@sliepen.warande.net>
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., 675 Mass Ave, Cambridge, MA 02139, USA.
$Id: net.c,v 1.35.4.82 2000/11/25 13:33:30 guus Exp $
*/
#include "config.h"
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/signal.h>
#include <sys/time.h>
#include <sys/types.h>
#include <syslog.h>
#include <unistd.h>
#include <sys/ioctl.h>
/* SunOS really wants sys/socket.h BEFORE net/if.h,
and FreeBSD wants these lines below the rest. */
#include <arpa/inet.h>
#include <sys/socket.h>
#include <net/if.h>
#ifdef HAVE_OPENSSL_RAND_H
# include <openssl/rand.h>
#else
# include <rand.h>
#endif
#ifdef HAVE_OPENSSL_EVP_H
# include <openssl/evp.h>
#else
# include <evp.h>
#endif
#ifdef HAVE_OPENSSL_ERR_H
# include <openssl/err.h>
#else
# include <err.h>
#endif
#ifdef HAVE_TUNTAP
#include LINUX_IF_TUN_H
#endif
#include <utils.h>
#include <xalloc.h>
#include "conf.h"
#include "connection.h"
#include "list.h"
#include "meta.h"
#include "net.h"
#include "netutl.h"
#include "process.h"
#include "protocol.h"
#include "subnet.h"
#include "system.h"
int tap_fd = -1;
int taptype = TAP_TYPE_ETHERTAP;
int total_tap_in = 0;
int total_tap_out = 0;
int total_socket_in = 0;
int total_socket_out = 0;
config_t *upstreamcfg;
static int seconds_till_retry;
int keylifetime = 0;
int keyexpires = 0;
char *unknown = NULL;
subnet_t mymac;
int xsend(connection_t *cl, vpn_packet_t *inpkt)
{
vpn_packet_t outpkt;
int outlen, outpad;
EVP_CIPHER_CTX ctx;
struct sockaddr_in to;
socklen_t tolen = sizeof(to);
cp
outpkt.len = inpkt->len;
/* Encrypt the packet */
EVP_EncryptInit(&ctx, cl->cipher_pkttype, cl->cipher_pktkey, cl->cipher_pktkey + cl->cipher_pkttype->key_len);
EVP_EncryptUpdate(&ctx, outpkt.data, &outlen, inpkt->data, inpkt->len);
EVP_EncryptFinal(&ctx, outpkt.data + outlen, &outpad);
outlen += outpad + 2;
/* Bypass
outlen = outpkt.len + 2;
memcpy(&outpkt, inpkt, outlen);
*/
if(debug_lvl >= DEBUG_TRAFFIC)
syslog(LOG_ERR, _("Sending packet of %d bytes to %s (%s)"),
outlen, cl->name, cl->hostname);
total_socket_out += outlen;
to.sin_family = AF_INET;
to.sin_addr.s_addr = htonl(cl->address);
to.sin_port = htons(cl->port);
if((sendto(myself->socket, (char *) &(outpkt.len), outlen, 0, (const struct sockaddr *)&to, tolen)) < 0)
{
syslog(LOG_ERR, _("Error sending packet to %s (%s): %m"),
cl->name, cl->hostname);
return -1;
}
cp
return 0;
}
int xrecv(connection_t *cl, vpn_packet_t *inpkt)
{
vpn_packet_t outpkt;
int outlen, outpad;
EVP_CIPHER_CTX ctx;
cp
outpkt.len = inpkt->len;
/* Decrypt the packet */
EVP_DecryptInit(&ctx, myself->cipher_pkttype, myself->cipher_pktkey, myself->cipher_pktkey + myself->cipher_pkttype->key_len);
EVP_DecryptUpdate(&ctx, outpkt.data, &outlen, inpkt->data, inpkt->len + 8);
EVP_DecryptFinal(&ctx, outpkt.data + outlen, &outpad);
outlen += outpad;
/* Bypass
outlen = outpkt.len+2;
memcpy(&outpkt, inpkt, outlen);
*/
if(debug_lvl >= DEBUG_TRAFFIC)
syslog(LOG_ERR, _("Writing packet of %d bytes to tap device"),
outpkt.len, outlen);
/* Fix mac address */
memcpy(outpkt.data, mymac.net.mac.address.x, 6);
if(taptype == TAP_TYPE_TUNTAP)
{
if(write(tap_fd, outpkt.data, outpkt.len) < 0)
syslog(LOG_ERR, _("Can't write to tun/tap device: %m"));
else
total_tap_out += outpkt.len;
}
else /* ethertap */
{
if(write(tap_fd, outpkt.data - 2, outpkt.len + 2) < 0)
syslog(LOG_ERR, _("Can't write to ethertap device: %m"));
else
total_tap_out += outpkt.len + 2;
}
cp
return 0;
}
/*
add the given packet of size s to the
queue q, be it the send or receive queue
*/
void add_queue(packet_queue_t **q, void *packet, size_t s)
{
queue_element_t *e;
cp
e = xmalloc(sizeof(*e));
e->packet = xmalloc(s);
memcpy(e->packet, packet, s);
if(!*q)
{
*q = xmalloc(sizeof(**q));
(*q)->head = (*q)->tail = NULL;
}
e->next = NULL; /* We insert at the tail */
if((*q)->tail) /* Do we have a tail? */
{
(*q)->tail->next = e;
e->prev = (*q)->tail;
}
else /* No tail -> no head too */
{
(*q)->head = e;
e->prev = NULL;
}
(*q)->tail = e;
cp
}
/* Remove a queue element */
void del_queue(packet_queue_t **q, queue_element_t *e)
{
cp
free(e->packet);
if(e->next) /* There is a successor, so we are not tail */
{
if(e->prev) /* There is a predecessor, so we are not head */
{
e->next->prev = e->prev;
e->prev->next = e->next;
}
else /* We are head */
{
e->next->prev = NULL;
(*q)->head = e->next;
}
}
else /* We are tail (or all alone!) */
{
if(e->prev) /* We are not alone :) */
{
e->prev->next = NULL;
(*q)->tail = e->prev;
}
else /* Adieu */
{
free(*q);
*q = NULL;
}
}
free(e);
cp
}
/*
flush a queue by calling function for
each packet, and removing it when that
returned a zero exit code
*/
void flush_queue(connection_t *cl, packet_queue_t **pq,
int (*function)(connection_t*,vpn_packet_t*))
{
queue_element_t *p, *next = NULL;
cp
for(p = (*pq)->head; p != NULL; )
{
next = p->next;
if(!function(cl, p->packet))
del_queue(pq, p);
p = next;
}
if(debug_lvl >= DEBUG_TRAFFIC)
syslog(LOG_DEBUG, _("Queue flushed"));
cp
}
/*
flush the send&recv queues
void because nothing goes wrong here, packets
remain in the queue if something goes wrong
*/
void flush_queues(connection_t *cl)
{
cp
if(cl->sq)
{
if(debug_lvl >= DEBUG_TRAFFIC)
syslog(LOG_DEBUG, _("Flushing send queue for %s (%s)"),
cl->name, cl->hostname);
flush_queue(cl, &(cl->sq), xsend);
}
if(cl->rq)
{
if(debug_lvl >= DEBUG_TRAFFIC)
syslog(LOG_DEBUG, _("Flushing receive queue for %s (%s)"),
cl->name, cl->hostname);
flush_queue(cl, &(cl->rq), xrecv);
}
cp
}
/*
send a packet to the given vpn ip.
*/
int send_packet(ip_t to, vpn_packet_t *packet)
{
connection_t *cl;
subnet_t *subnet;
cp
if((subnet = lookup_subnet_ipv4(to)) == NULL)
{
if(debug_lvl >= DEBUG_TRAFFIC)
{
syslog(LOG_NOTICE, _("Trying to look up %d.%d.%d.%d in connection list failed!"),
IP_ADDR_V(to));
}
return -1;
}
cl = subnet->owner;
if(cl == myself)
{
if(debug_lvl >= DEBUG_TRAFFIC)
{
syslog(LOG_NOTICE, _("Packet with destination %d.%d.%d.%d is looping back to us!"),
IP_ADDR_V(to));
}
return -1;
}
/* If we ourselves have indirectdata flag set, we should send only to our uplink! */
/* FIXME - check for indirection and reprogram it The Right Way(tm) this time. */
if(!cl->status.validkey)
{
/* FIXME: Don't queue until everything else is fixed.
if(debug_lvl >= DEBUG_TRAFFIC)
syslog(LOG_INFO, _("No valid key known yet for %s (%s), queueing packet"),
cl->name, cl->hostname);
add_queue(&(cl->sq), packet, packet->len + 2);
*/
if(!cl->status.waitingforkey)
send_req_key(myself, cl); /* Keys should be sent to the host running the tincd */
return 0;
}
if(!cl->status.active)
{
/* FIXME: Don't queue until everything else is fixed.
if(debug_lvl >= DEBUG_TRAFFIC)
syslog(LOG_INFO, _("%s (%s) is not ready, queueing packet"),
cl->name, cl->hostname);
add_queue(&(cl->sq), packet, packet->len + 2);
*/
return 0; /* We don't want to mess up, do we? */
}
/* can we send it? can we? can we? huh? */
cp
return xsend(cl, packet);
}
/*
open the local ethertap device
*/
int setup_tap_fd(void)
{
int nfd;
const char *tapfname;
config_t const *cfg;
#ifdef HAVE_LINUX
#ifdef HAVE_TUNTAP
struct ifreq ifr;
#endif
#endif
cp
if((cfg = get_config_val(config, config_tapdevice)))
tapfname = cfg->data.ptr;
else
{
#ifdef HAVE_LINUX
#ifdef HAVE_TUNTAP
tapfname = "/dev/misc/net/tun";
#else
tapfname = "/dev/tap0";
#endif
#endif
#ifdef HAVE_FREEBSD
tapfname = "/dev/tap0";
#endif
#ifdef HAVE_SOLARIS
tapfname = "/dev/tun";
#endif
}
cp
if((nfd = open(tapfname, O_RDWR | O_NONBLOCK)) < 0)
{
syslog(LOG_ERR, _("Could not open %s: %m"), tapfname);
return -1;
}
cp
tap_fd = nfd;
taptype = TAP_TYPE_ETHERTAP;
/* Set default MAC address for ethertap devices */
mymac.type = SUBNET_MAC;
mymac.net.mac.address.x[0] = 0xfe;
mymac.net.mac.address.x[1] = 0xfd;
mymac.net.mac.address.x[2] = 0x00;
mymac.net.mac.address.x[3] = 0x00;
mymac.net.mac.address.x[4] = 0x00;
mymac.net.mac.address.x[5] = 0x00;
#ifdef HAVE_LINUX
#ifdef HAVE_TUNTAP
/* Ok now check if this is an old ethertap or a new tun/tap thingie */
memset(&ifr, 0, sizeof(ifr));
cp
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
if (netname)
strncpy(ifr.ifr_name, netname, IFNAMSIZ);
cp
if (!ioctl(tap_fd, TUNSETIFF, (void *) &ifr))
{
syslog(LOG_INFO, _("%s is a new style tun/tap device"), tapfname);
taptype = TAP_TYPE_TUNTAP;
}
#endif
#endif
#ifdef HAVE_FREEBSD
taptype = TAP_TYPE_TUNTAP;
#endif
cp
return 0;
}
/*
set up the socket that we listen on for incoming
(tcp) connections
*/
int setup_listen_meta_socket(int port)
{
int nfd, flags;
struct sockaddr_in a;
const int one = 1;
config_t const *cfg;
cp
if((nfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
{
syslog(LOG_ERR, _("Creating metasocket failed: %m"));
return -1;
}
if(setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)))
{
close(nfd);
syslog(LOG_ERR, _("System call `%s' failed: %m"),
"setsockopt");
return -1;
}
if(setsockopt(nfd, SOL_SOCKET, SO_KEEPALIVE, &one, sizeof(one)))
{
close(nfd);
syslog(LOG_ERR, _("System call `%s' failed: %m"),
"setsockopt");
return -1;
}
flags = fcntl(nfd, F_GETFL);
if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
{
close(nfd);
syslog(LOG_ERR, _("System call `%s' failed: %m"),
"fcntl");
return -1;
}
if((cfg = get_config_val(config, config_interface)))
{
if(setsockopt(nfd, SOL_SOCKET, SO_KEEPALIVE, cfg->data.ptr, strlen(cfg->data.ptr)))
{
close(nfd);
syslog(LOG_ERR, _("Unable to bind listen socket to interface %s: %m"), cfg->data.ptr);
return -1;
}
}
memset(&a, 0, sizeof(a));
a.sin_family = AF_INET;
a.sin_port = htons(port);
if((cfg = get_config_val(config, config_interfaceip)))
a.sin_addr.s_addr = htonl(cfg->data.ip->address);
else
a.sin_addr.s_addr = htonl(INADDR_ANY);
if(bind(nfd, (struct sockaddr *)&a, sizeof(struct sockaddr)))
{
close(nfd);
syslog(LOG_ERR, _("Can't bind to port %hd/tcp: %m"), port);
return -1;
}
if(listen(nfd, 3))
{
close(nfd);
syslog(LOG_ERR, _("System call `%s' failed: %m"),
"listen");
return -1;
}
cp
return nfd;
}
/*
setup the socket for incoming encrypted
data (the udp part)
*/
int setup_vpn_in_socket(int port)
{
int nfd, flags;
struct sockaddr_in a;
const int one = 1;
cp
if((nfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
{
close(nfd);
syslog(LOG_ERR, _("Creating socket failed: %m"));
return -1;
}
if(setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)))
{
close(nfd);
syslog(LOG_ERR, _("System call `%s' failed: %m"),
"setsockopt");
return -1;
}
flags = fcntl(nfd, F_GETFL);
if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
{
close(nfd);
syslog(LOG_ERR, _("System call `%s' failed: %m"),
"fcntl");
return -1;
}
memset(&a, 0, sizeof(a));
a.sin_family = AF_INET;
a.sin_port = htons(port);
a.sin_addr.s_addr = htonl(INADDR_ANY);
if(bind(nfd, (struct sockaddr *)&a, sizeof(struct sockaddr)))
{
close(nfd);
syslog(LOG_ERR, _("Can't bind to port %hd/udp: %m"), port);
return -1;
}
cp
return nfd;
}
/*
setup an outgoing meta (tcp) socket
*/
int setup_outgoing_meta_socket(connection_t *cl)
{
int flags;
struct sockaddr_in a;
config_t const *cfg;
cp
if(debug_lvl >= DEBUG_CONNECTIONS)
syslog(LOG_INFO, _("Trying to connect to %s"), cl->hostname);
if((cfg = get_config_val(cl->config, config_port)) == NULL)
cl->port = 655;
else
cl->port = cfg->data.val;
cl->meta_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if(cl->meta_socket == -1)
{
syslog(LOG_ERR, _("Creating socket for %s port %d failed: %m"),
cl->hostname, cl->port);
return -1;
}
a.sin_family = AF_INET;
a.sin_port = htons(cl->port);
a.sin_addr.s_addr = htonl(cl->address);
if(connect(cl->meta_socket, (struct sockaddr *)&a, sizeof(a)) == -1)
{
close(cl->meta_socket);
syslog(LOG_ERR, _("%s port %hd: %m"), cl->hostname, cl->port);
return -1;
}
flags = fcntl(cl->meta_socket, F_GETFL);
if(fcntl(cl->meta_socket, F_SETFL, flags | O_NONBLOCK) < 0)
{
close(cl->meta_socket);
syslog(LOG_ERR, _("fcntl for %s port %d: %m"),
cl->hostname, cl->port);
return -1;
}
if(debug_lvl >= DEBUG_CONNECTIONS)
syslog(LOG_INFO, _("Connected to %s port %hd"),
cl->hostname, cl->port);
cl->status.meta = 1;
cp
return 0;
}
/*
Setup an outgoing meta connection.
*/
int setup_outgoing_connection(char *name)
{
connection_t *ncn;
struct hostent *h;
config_t const *cfg;
cp
if(check_id(name))
{
syslog(LOG_ERR, _("Invalid name for outgoing connection"));
return -1;
}
ncn = new_connection();
asprintf(&ncn->name, "%s", name);
if(read_host_config(ncn))
{
syslog(LOG_ERR, _("Error reading host configuration file for %s"));
free_connection(ncn);
return -1;
}
if(!(cfg = get_config_val(ncn->config, config_address)))
{
syslog(LOG_ERR, _("No address specified for %s"));
free_connection(ncn);
return -1;
}
if(!(h = gethostbyname(cfg->data.ptr)))
{
syslog(LOG_ERR, _("Error looking up `%s': %m"), cfg->data.ptr);
free_connection(ncn);
return -1;
}
ncn->address = ntohl(*((ip_t*)(h->h_addr_list[0])));
ncn->hostname = hostlookup(htonl(ncn->address));
if(setup_outgoing_meta_socket(ncn) < 0)
{
syslog(LOG_ERR, _("Could not set up a meta connection to %s"),
ncn->hostname);
free_connection(ncn);
return -1;
}
ncn->status.outgoing = 1;
ncn->buffer = xmalloc(MAXBUFSIZE);
ncn->buflen = 0;
ncn->last_ping_time = time(NULL);
connection_add(ncn);
send_id(ncn);
cp
return 0;
}
/*
Configure connection_t myself and set up the local sockets (listen only)
*/
int setup_myself(void)
{
config_t const *cfg;
config_t *next;
subnet_t *net;
cp
myself = new_connection();
asprintf(&myself->hostname, "MYSELF"); /* FIXME? Do hostlookup on ourselves? */
myself->flags = 0;
myself->protocol_version = PROT_CURRENT;
if(!(cfg = get_config_val(config, config_name))) /* Not acceptable */
{
syslog(LOG_ERR, _("Name for tinc daemon required!"));
return -1;
}
else
asprintf(&myself->name, "%s", (char*)cfg->data.val);
if(check_id(myself->name))
{
syslog(LOG_ERR, _("Invalid name for myself!"));
return -1;
}
cp
if(!(cfg = get_config_val(config, config_privatekey)))
{
syslog(LOG_ERR, _("Private key for tinc daemon required!"));
return -1;
}
else
{
myself->rsa_key = RSA_new();
BN_hex2bn(&myself->rsa_key->d, cfg->data.ptr);
BN_hex2bn(&myself->rsa_key->e, "FFFF");
}
if(read_host_config(myself))
{
syslog(LOG_ERR, _("Cannot open host configuration file for myself!"));
return -1;
}
cp
if(!(cfg = get_config_val(myself->config, config_publickey)))
{
syslog(LOG_ERR, _("Public key for tinc daemon required!"));
return -1;
}
else
{
BN_hex2bn(&myself->rsa_key->n, cfg->data.ptr);
}
/*
if(RSA_check_key(myself->rsa_key) != 1)
{
syslog(LOG_ERR, _("Invalid public/private keypair!"));
return -1;
}
*/
if(!(cfg = get_config_val(myself->config, config_port)))
myself->port = 655;
else
myself->port = cfg->data.val;
if((cfg = get_config_val(myself->config, config_indirectdata)))
if(cfg->data.val == stupid_true)
myself->flags |= EXPORTINDIRECTDATA;
if((cfg = get_config_val(myself->config, config_tcponly)))
if(cfg->data.val == stupid_true)
myself->flags |= TCPONLY;
/* Read in all the subnets specified in the host configuration file */
for(next = myself->config; (cfg = get_config_val(next, config_subnet)); next = cfg->next)
{
net = new_subnet();
net->type = SUBNET_IPV4;
net->net.ipv4.address = cfg->data.ip->address;
net->net.ipv4.mask = cfg->data.ip->mask;
/* Teach newbies what subnets are... */
if((net->net.ipv4.address & net->net.ipv4.mask) != net->net.ipv4.address)
{
syslog(LOG_ERR, _("Network address and subnet mask do not match!"));
return -1;
}
subnet_add(myself, net);
}
if((myself->meta_socket = setup_listen_meta_socket(myself->port)) < 0)
{
syslog(LOG_ERR, _("Unable to set up a listening TCP socket!"));
return -1;
}
if((myself->socket = setup_vpn_in_socket(myself->port)) < 0)
{
syslog(LOG_ERR, _("Unable to set up a listening UDP socket!"));
return -1;
}
/* Generate packet encryption key */
myself->cipher_pkttype = EVP_bf_cfb();
myself->cipher_pktkeylength = myself->cipher_pkttype->key_len + myself->cipher_pkttype->iv_len;
myself->cipher_pktkey = (char *)xmalloc(myself->cipher_pktkeylength);
RAND_bytes(myself->cipher_pktkey, myself->cipher_pktkeylength);
if(!(cfg = get_config_val(config, config_keyexpire)))
keylifetime = 3600;
else
keylifetime = cfg->data.val;
keyexpires = time(NULL) + keylifetime;
/* Activate ourselves */
myself->status.active = 1;
syslog(LOG_NOTICE, _("Ready: listening on port %hd"), myself->port);
cp
return 0;
}
RETSIGTYPE
sigalrm_handler(int a)
{
config_t const *cfg;
cp
cfg = get_config_val(upstreamcfg, config_connectto);
if(!cfg && upstreamcfg == config)
/* No upstream IP given, we're listen only. */
return;
while(cfg)
{
upstreamcfg = cfg->next;
if(!setup_outgoing_connection(cfg->data.ptr)) /* function returns 0 when there are no problems */
{
signal(SIGALRM, SIG_IGN);
return;
}
cfg = get_config_val(upstreamcfg, config_connectto); /* Or else we try the next ConnectTo line */
}
signal(SIGALRM, sigalrm_handler);
upstreamcfg = config;
seconds_till_retry += 5;
if(seconds_till_retry > MAXTIMEOUT) /* Don't wait more than MAXTIMEOUT seconds. */
seconds_till_retry = MAXTIMEOUT;
syslog(LOG_ERR, _("Still failed to connect to other, will retry in %d seconds"),
seconds_till_retry);
alarm(seconds_till_retry);
cp
}
/*
setup all initial network connections
*/
int setup_network_connections(void)
{
config_t const *cfg;
cp
init_connections();
init_subnets();
if((cfg = get_config_val(config, config_pingtimeout)) == NULL)
timeout = 60;
else
{
timeout = cfg->data.val;
if(timeout < 1)
{
timeout = 86400;
}
}
if(setup_tap_fd() < 0)
return -1;
/* Run tinc-up script to further initialize the tap interface */
execute_script("tinc-up");
if(setup_myself() < 0)
return -1;
if(!(cfg = get_config_val(config, config_connectto)))
/* No upstream IP given, we're listen only. */
return 0;
while(cfg)
{
upstreamcfg = cfg->next;
if(!setup_outgoing_connection(cfg->data.ptr)) /* function returns 0 when there are no problems */
return 0;
cfg = get_config_val(upstreamcfg, config_connectto); /* Or else we try the next ConnectTo line */
}
signal(SIGALRM, sigalrm_handler);
upstreamcfg = config;
seconds_till_retry = MAXTIMEOUT;
syslog(LOG_NOTICE, _("Trying to re-establish outgoing connection in %d seconds"), seconds_till_retry);
alarm(seconds_till_retry);
cp
return 0;
}
/*
close all open network connections
*/
void close_network_connections(void)
{
rbl_t *rbl;
connection_t *p;
cp
RBL_FOREACH(connection_tree, rbl)
{
p = (connection_t *)rbl->data;
p->status.active = 0;
terminate_connection(p);
}
if(myself)
if(myself->status.active)
{
close(myself->meta_socket);
free_connection(myself);
myself = NULL;
}
close(tap_fd);
/* Execute tinc-down script right after shutting down the interface */
execute_script("tinc-down");
destroy_connection_tree();
cp
return;
}
/*
create a data (udp) socket
OBSOLETED: use only one listening socket for compatibility with non-Linux operating systems
*/
int setup_vpn_connection(connection_t *cl)
{
int nfd, flags;
struct sockaddr_in a;
const int one = 1;
cp
if(debug_lvl >= DEBUG_TRAFFIC)
syslog(LOG_DEBUG, _("Opening UDP socket to %s"), cl->hostname);
nfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if(nfd == -1)
{
syslog(LOG_ERR, _("Creating UDP socket failed: %m"));
return -1;
}
if(setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)))
{
close(nfd);
syslog(LOG_ERR, _("System call `%s' failed: %m"),
"setsockopt");
return -1;
}
flags = fcntl(nfd, F_GETFL);
if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
{
close(nfd);
syslog(LOG_ERR, _("System call `%s' failed: %m"),
"fcntl");
return -1;
}
memset(&a, 0, sizeof(a));
a.sin_family = AF_INET;
a.sin_port = htons(myself->port);
a.sin_addr.s_addr = htonl(INADDR_ANY);
if(bind(nfd, (struct sockaddr *)&a, sizeof(struct sockaddr)))
{
close(nfd);
syslog(LOG_ERR, _("Can't bind to port %hd/udp: %m"), myself->port);
return -1;
}
a.sin_family = AF_INET;
a.sin_port = htons(cl->port);
a.sin_addr.s_addr = htonl(cl->address);
if(connect(nfd, (struct sockaddr *)&a, sizeof(a)) == -1)
{
close(nfd);
syslog(LOG_ERR, _("Connecting to %s port %d failed: %m"),
cl->hostname, cl->port);
return -1;
}
flags = fcntl(nfd, F_GETFL);
if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
{
close(nfd);
syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%m %s (%s)"), __FILE__, __LINE__, nfd,
cl->name, cl->hostname);
return -1;
}
cl->socket = nfd;
cl->status.dataopen = 1;
cp
return 0;
}
/*
handle an incoming tcp connect call and open
a connection to it.
*/
connection_t *create_new_connection(int sfd)
{
connection_t *p;
struct sockaddr_in ci;
int len = sizeof(ci);
cp
p = new_connection();
if(getpeername(sfd, (struct sockaddr *) &ci, (socklen_t *) &len) < 0)
{
syslog(LOG_ERR, _("System call `%s' failed: %m"),
"getpeername");
return NULL;
}
p->name = unknown;
p->address = ntohl(ci.sin_addr.s_addr);
p->hostname = hostlookup(ci.sin_addr.s_addr);
p->meta_socket = sfd;
p->status.meta = 1;
p->buffer = xmalloc(MAXBUFSIZE);
p->buflen = 0;
p->last_ping_time = time(NULL);
if(debug_lvl >= DEBUG_CONNECTIONS)
syslog(LOG_NOTICE, _("Connection from %s port %d"),
p->hostname, htons(ci.sin_port));
p->allow_request = ID;
cp
return p;
}
/*
put all file descriptors in an fd_set array
*/
void build_fdset(fd_set *fs)
{
rbl_t *rbl;
connection_t *p;
cp
FD_ZERO(fs);
FD_SET(myself->socket, fs);
RBL_FOREACH(connection_tree, rbl)
{
p = (connection_t *)rbl->data;
if(p->status.meta)
FD_SET(p->meta_socket, fs);
}
FD_SET(myself->meta_socket, fs);
FD_SET(tap_fd, fs);
cp
}
/*
receive incoming data from the listening
udp socket and write it to the ethertap
device after being decrypted
*/
int handle_incoming_vpn_data(void)
{
vpn_packet_t pkt;
int x, l = sizeof(x);
int lenin;
struct sockaddr_in from;
socklen_t fromlen = sizeof(from);
connection_t *cl;
cp
if(getsockopt(myself->socket, SOL_SOCKET, SO_ERROR, &x, &l) < 0)
{
syslog(LOG_ERR, _("This is a bug: %s:%d: %d:%m"),
__FILE__, __LINE__, myself->socket);
return -1;
}
if(x)
{
syslog(LOG_ERR, _("Incoming data socket error: %s"), strerror(x));
return -1;
}
if((lenin = recvfrom(myself->socket, (char *) &(pkt.len), MTU, 0, (struct sockaddr *)&from, &fromlen)) <= 0)
{
syslog(LOG_ERR, _("Receiving packet failed: %m"));
return -1;
}
cl = lookup_connection(ntohl(from.sin_addr.s_addr), ntohs(from.sin_port));
if(!cl)
{
syslog(LOG_WARNING, _("Received UDP packets on port %d from unknown source %lx:%d"), ntohl(from.sin_addr.s_addr), ntohs(from.sin_port));
return 0;
}
if(debug_lvl >= DEBUG_TRAFFIC)
{
syslog(LOG_DEBUG, _("Received packet of %d bytes from %s (%s)"), lenin,
cl->name, cl->hostname);
}
cp
return xrecv(cl, &pkt);
}
/*
terminate a connection and notify the other
end before closing the sockets
*/
void terminate_connection(connection_t *cl)
{
connection_t *p;
subnet_t *subnet;
rbl_t *rbl;
cp
if(cl->status.remove)
return;
cl->status.remove = 1;
if(debug_lvl >= DEBUG_CONNECTIONS)
syslog(LOG_NOTICE, _("Closing connection with %s (%s)"),
cl->name, cl->hostname);
if(cl->socket)
close(cl->socket);
if(cl->status.meta)
close(cl->meta_socket);
/* Find all connections that were lost because they were behind cl
(the connection that was dropped). */
if(cl->status.meta)
RBL_FOREACH(connection_tree, rbl)
{
p = (connection_t *)rbl->data;
if(p->nexthop == cl && p != cl)
terminate_connection(p);
}
/* Inform others of termination if it was still active */
if(cl->status.active)
RBL_FOREACH(connection_tree, rbl)
{
p = (connection_t *)rbl->data;
if(p->status.meta && p->status.active && p!=cl)
send_del_host(p, cl); /* Sounds like recursion, but p does not have a meta connection :) */
}
/* Remove the associated subnets */
RBL_FOREACH(cl->subnet_tree, rbl)
{
subnet = (subnet_t *)rbl->data;
subnet_del(subnet);
}
/* Check if this was our outgoing connection */
if(cl->status.outgoing && cl->status.active)
{
signal(SIGALRM, sigalrm_handler);
seconds_till_retry = 5;
alarm(seconds_till_retry);
syslog(LOG_NOTICE, _("Trying to re-establish outgoing connection in 5 seconds"));
}
/* Inactivate */
cl->status.active = 0;
cp
}
/*
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.
*/
void check_dead_connections(void)
{
time_t now;
rbl_t *rbl;
connection_t *cl;
cp
now = time(NULL);
RBL_FOREACH(connection_tree, rbl)
{
cl = (connection_t *)rbl->data;
if(cl->status.active && cl->status.meta)
{
if(cl->last_ping_time + timeout < now)
{
if(cl->status.pinged)
{
if(debug_lvl >= DEBUG_PROTOCOL)
syslog(LOG_INFO, _("%s (%s) didn't respond to PING"),
cl->name, cl->hostname);
cl->status.timeout = 1;
terminate_connection(cl);
}
else
{
send_ping(cl);
}
}
}
}
cp
}
/*
accept a new tcp connect and create a
new connection
*/
int handle_new_meta_connection()
{
connection_t *ncn;
struct sockaddr client;
int nfd, len = sizeof(client);
cp
if((nfd = accept(myself->meta_socket, &client, &len)) < 0)
{
syslog(LOG_ERR, _("Accepting a new connection failed: %m"));
return -1;
}
if(!(ncn = create_new_connection(nfd)))
{
shutdown(nfd, 2);
close(nfd);
syslog(LOG_NOTICE, _("Closed attempted connection"));
return 0;
}
connection_add(ncn);
cp
return 0;
}
/*
check all connections to see if anything
happened on their sockets
*/
void check_network_activity(fd_set *f)
{
connection_t *p;
rbl_t *rbl;
cp
if(FD_ISSET(myself->socket, f))
handle_incoming_vpn_data();
RBL_FOREACH(connection_tree, rbl)
{
p = (connection_t *)rbl->data;
if(p->status.remove)
return;
if(p->status.meta)
if(FD_ISSET(p->meta_socket, f))
if(receive_meta(p) < 0)
{
terminate_connection(p);
return;
}
}
if(FD_ISSET(myself->meta_socket, f))
handle_new_meta_connection();
cp
}
/*
read, encrypt and send data that is
available through the ethertap device
*/
void handle_tap_input(void)
{
vpn_packet_t vp;
int lenin;
cp
if(taptype == TAP_TYPE_TUNTAP)
{
if((lenin = read(tap_fd, vp.data, MTU)) <= 0)
{
syslog(LOG_ERR, _("Error while reading from tun/tap device: %m"));
return;
}
vp.len = lenin;
}
else /* ethertap */
{
if((lenin = read(tap_fd, vp.data - 2, MTU)) <= 0)
{
syslog(LOG_ERR, _("Error while reading from ethertap device: %m"));
return;
}
vp.len = lenin - 2;
}
total_tap_in += lenin;
if(lenin < 32)
{
if(debug_lvl >= DEBUG_TRAFFIC)
syslog(LOG_WARNING, _("Received short packet from tap device"));
return;
}
if(debug_lvl >= DEBUG_TRAFFIC)
{
syslog(LOG_DEBUG, _("Read packet of length %d from tap device"), vp.len);
}
send_packet(ntohl(*((unsigned long*)(&vp.data[30]))), &vp);
cp
}
/*
this is where it all happens...
*/
void main_loop(void)
{
fd_set fset;
struct timeval tv;
int r;
time_t last_ping_check;
int t;
cp
last_ping_check = time(NULL);
for(;;)
{
tv.tv_sec = timeout;
tv.tv_usec = 0;
prune_connection_tree();
build_fdset(&fset);
if((r = select(FD_SETSIZE, &fset, NULL, NULL, &tv)) < 0)
{
if(errno != EINTR) /* because of alarm */
{
syslog(LOG_ERR, _("Error while waiting for input: %m"));
return;
}
}
if(sighup)
{
syslog(LOG_INFO, _("Rereading configuration file and restarting in 5 seconds"));
sighup = 0;
close_network_connections();
clear_config(&config);
if(read_server_config())
{
syslog(LOG_ERR, _("Unable to reread configuration file, exiting"));
exit(0);
}
sleep(5);
if(setup_network_connections())
return;
continue;
}
t = time(NULL);
/* Let's check if everybody is still alive */
if(last_ping_check + timeout < t)
{
check_dead_connections();
last_ping_check = time(NULL);
/* Should we regenerate our key? */
if(keyexpires < t)
{
if(debug_lvl >= DEBUG_STATUS)
syslog(LOG_INFO, _("Regenerating symmetric key"));
RAND_bytes(myself->cipher_pktkey, myself->cipher_pktkeylength);
send_key_changed(myself, NULL);
keyexpires = time(NULL) + keylifetime;
}
}
if(r > 0)
{
check_network_activity(&fset);
/* local tap data */
if(FD_ISSET(tap_fd, &fset))
handle_tap_input();
}
}
cp
}
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