#!/usr/bin/perl

use warnings;
use strict;

use STUN::RFC_5389;
use IO::Socket::INET;

die "$0 <server> [port]\n" unless $#ARGV >= 0;
my ($server,$port) = @ARGV;
$port = $port // 3478;

my $request = Client STUN::RFC_5389 { request => 1 };
my $lport = 10000+(int rand 55536);

my $socket = new IO::Socket::INET (
	LocalPort => $lport,
	PeerAddr => $server,
	PeerPort => $port,
	Proto => 'udp',
) || die "connect: $@\n";
send($socket,$request,0);

my $response;
recv($socket,$response,1024,0);
close($socket);

my $mapped_address = ${Client STUN::RFC_5389 $response}{attributes}->{'MAPPED-ADDRESS'};
print $mapped_address->{address},":",$mapped_address->{port},"\n";

my $listen = new IO::Socket::INET (
	LocalPort => $lport,
	Proto => 'udp',
) || die "bind: $@\n";

my $buf;
$|=1;
while ($listen->recv($buf,1)) { print $buf }
die "recv: $!\n";