int udp_session(struct vtun_host *host)
{
struct sockaddr_in saddr;
short port;
int s, opt;
extern int is_rmt_fd_connected;
if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
vtun_syslog(LOG_ERR, "Can't create socket");
return -1;
}
opt = 1;
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
/* Set local address and port */
local_addr(&saddr, host, 1);
if (bind(s, (struct sockaddr *) &saddr, sizeof(saddr))) {
vtun_syslog(LOG_ERR, "Can't bind to the socket");
return -1;
}
opt = sizeof(saddr);
if (getsockname(s, (struct sockaddr *) &saddr, &opt)) {
vtun_syslog(LOG_ERR, "Can't get socket name");
return -1;
}
/* Write port of the new UDP socket */
port = saddr.sin_port;
if (write_n(host->rmt_fd, (char *) &port, sizeof(short)) < 0) {
vtun_syslog(LOG_ERR, "Can't write port number");
return -1;
}
host->sopt.lport = htons(port);
/* Read port of the other's end UDP socket */
if (readn_t(host->rmt_fd, &port, sizeof(short), host->timeout) < 0) {
vtun_syslog(LOG_ERR, "Can't read port number %s", strerror(errno));
return -1;
}
opt = sizeof(saddr);
if (getpeername(host->rmt_fd, (struct sockaddr *) &saddr, &opt)) {
vtun_syslog(LOG_ERR, "Can't get peer name");
return -1;
}
saddr.sin_port = port;
/* if the config says to delay the UDP connection, we wait for an
incoming packet and then force a connection back. We need to
put this here because we need to keep that incoming triggering
packet and pass it back up the chain. */
if (VTUN_USE_NAT_HACK(host))
is_rmt_fd_connected = 0;
else {
if (connect(s, (struct sockaddr *) &saddr, sizeof(saddr))) {
vtun_syslog(LOG_ERR, "Can't connect socket");
return -1;
}
is_rmt_fd_connected = 1;
}
host->sopt.rport = htons(port);
/* Close TCP socket and replace with UDP socket */
close(host->rmt_fd);
host->rmt_fd = s;
vtun_syslog(LOG_INFO, "UDP connection initialized");
return s;
}
static int lfd_linker(void)
{
int fd1 = lfd_host->rmt_fd;
int fd2 = lfd_host->loc_fd;
register int len, fl;
struct timeval tv;
char *buf, *out;
fd_set fdset;
int maxfd, idle = 0, tmplen;
if( !(buf = lfd_alloc(VTUN_FRAME_SIZE + VTUN_FRAME_OVERHEAD)) ){
vtun_syslog(LOG_ERR,"Can't allocate buffer for the linker");
return 0;
}
/* Delay sending of first UDP packet over broken NAT routers
because we will probably be disconnected. Wait for the remote
end to send us something first, and use that connection. */
if (!VTUN_USE_NAT_HACK(lfd_host))
proto_write(fd1, buf, VTUN_ECHO_REQ);
maxfd = (fd1 > fd2 ? fd1 : fd2) + 1;
linker_term = 0;
while( !linker_term ){
errno = 0;
/* Wait for data */
FD_ZERO(&fdset);
FD_SET(fd1, &fdset);
FD_SET(fd2, &fdset);
tv.tv_sec = lfd_host->ka_interval;
tv.tv_usec = 0;
if( (len = select(maxfd, &fdset, NULL, NULL, &tv)) < 0 ){
if( errno != EAGAIN && errno != EINTR )
break;
else
continue;
}
if( ka_need_verify ){
if( idle > lfd_host->ka_maxfail ){
vtun_syslog(LOG_INFO,"Session %s network timeout", lfd_host->host);
break;
}
if (idle++ > 0) { /* No input frames, check connection with ECHO */
if( proto_write(fd1, buf, VTUN_ECHO_REQ) < 0 ){
vtun_syslog(LOG_ERR,"Failed to send ECHO_REQ");
break;
}
}
ka_need_verify = 0;
}
if (send_a_packet)
{
send_a_packet = 0;
tmplen = 1;
lfd_host->stat.byte_out += tmplen;
if( (tmplen=lfd_run_down(tmplen,buf,&out)) == -1 )
break;
if( tmplen && proto_write(fd1, out, tmplen) < 0 )
break;
lfd_host->stat.comp_out += tmplen;
}
/* Read frames from network(fd1), decode and pass them to
* the local device (fd2) */
if( FD_ISSET(fd1, &fdset) && lfd_check_up() ){
idle = 0; ka_need_verify = 0;
if( (len=proto_read(fd1, buf)) <= 0 )
break;
/* Handle frame flags */
fl = len & ~VTUN_FSIZE_MASK;
len = len & VTUN_FSIZE_MASK;
if( fl ){
if( fl==VTUN_BAD_FRAME ){
vtun_syslog(LOG_ERR, "Received bad frame");
continue;
}
if( fl==VTUN_ECHO_REQ ){
/* Send ECHO reply */
if( proto_write(fd1, buf, VTUN_ECHO_REP) < 0 )
break;
continue;
}
if( fl==VTUN_ECHO_REP ){
/* Just ignore ECHO reply, ka_need_verify==0 already */
continue;
}
if( fl==VTUN_CONN_CLOSE ){
vtun_syslog(LOG_INFO,"Connection closed by other side");
break;
}
}
lfd_host->stat.comp_in += len;
if( (len=lfd_run_up(len,buf,&out)) == -1 )
break;
if( len && dev_write(fd2,out,len) < 0 ){
if( errno != EAGAIN && errno != EINTR )
break;
else
continue;
}
lfd_host->stat.byte_in += len;
}
/* Read data from the local device(fd2), encode and pass it to
* the network (fd1) */
if( FD_ISSET(fd2, &fdset) && lfd_check_down() ){
if( (len = dev_read(fd2, buf, VTUN_FRAME_SIZE)) < 0 ){
if( errno != EAGAIN && errno != EINTR )
break;
else
continue;
}
if( !len ) break;
lfd_host->stat.byte_out += len;
if( (len=lfd_run_down(len,buf,&out)) == -1 )
break;
if( len && proto_write(fd1, out, len) < 0 )
break;
lfd_host->stat.comp_out += len;
}
}
if( !linker_term && errno )
vtun_syslog(LOG_INFO,"%s (%d)", strerror(errno), errno);
if (linker_term == VTUN_SIG_TERM) {
lfd_host->persist = 0;
}
/* Notify other end about our close */
proto_write(fd1, buf, VTUN_CONN_CLOSE);
lfd_free(buf);
return 0;
}
