#!/usr/bin/perl -w

# tunnel.pl 
#
# Usage: tunnel.pl telnet-proxy telnet-proxy-port destination-host destination-port
#
# Ssh-tunnel over a telnet proxy.  
#
# Written for HTTP CONNECT by Urban Kaveus <urban@statt.ericsson.se>,
# modified by Simon Josefsson <simon@josefsson.org> June 2000.


if ( $#ARGV != 3 ) {
    print STDERR "Usage: $0 ssl-proxy port destination port\n";
    exit(1);
}
$AF_INET = 2;

if ($ENV{"OSTYPE"} eq "SunOS5") {
    $SOCK_STREAM = 2;
} else {
    $SOCK_STREAM = 1;
}

$sslproxy = shift;
$proxyport = shift;
$destination = shift;
$destport = shift;

# Set up network communication

($protocol) = (getprotobyname("tcp"))[2];
($proxyip) = (gethostbyname($sslproxy))[4];
$localaddr = pack('S n a4 x8', $AF_INET, 0, "\0\0\0\0");
$proxyaddr = pack('S n a4 x8', $AF_INET, $proxyport, $proxyip);

socket (PROXY, $AF_INET, $SOCK_STREAM, $protocol) or
die("Failed to create socket: $!\n");
bind (PROXY, $localaddr) or
die("Failed to bind socket");
connect (PROXY, $proxyaddr) or
die("Failed to connect to $sslproxy port $proxyport");

# Force flushing of socket buffers

select (PROXY); $| = 1;
select (STDOUT); $| = 1;

print PROXY "CONNECT $destination $destport\r\n";

while(<PROXY>) {
    chomp; # Strip <LF>
    last if /^Connected/;
}

# Start copying packets in both directions.

if($child = fork) { # Parent process
    while (sysread(STDIN,$_,4096)) {
	print PROXY;
    }
    sleep 2;
    kill(15,$child) if $child;
} else { # Child process
    while (sysread(PROXY,$_,4096)) {
	print STDOUT;
    }
}