#!/usr/bin/perl
# Seized-Server v1.0
# AE GPL 2005

use FileHandle;
use IPC::Open2;
use IO::Socket;
use strict;

# User config
my $PORT=6969;
my $HASH_FUNCTION="md5sum"; # sha1sum also works
my $FREQ = 0.25; # How often to send responses, seconds
my $verbose = 0;
# End user config

sub md5 
{
	my $string = shift;

	open2(*MD5_IN, *MD5_OUT, $HASH_FUNCTION);

	print MD5_OUT "$string\n";
	close(MD5_OUT);

	my $val = <MD5_IN>;
	
	close(MD5_IN);

	chomp($val);
	return $val;
}

sub main
{
	print "Enter today's peer password: ";
	system("stty -echo");
	my $pass = <STDIN>;
	system("stty echo");
	print "\n\n";

	
	local $SIG{PIPE} = 'IGNORE';
	local $SIG{CHLD} = sub { wait };

	my $server = IO::Socket::INET->new( Proto     => 'tcp',
			LocalPort => $PORT,
			Listen    => SOMAXCONN,
			Reuse     => 1);


	while(my $client = $server->accept()) {
		$client->autoflush(1);

		while(<$client>) {
			my $challenge = $_;
			chomp($challenge);

			if($verbose) {
				print "Read Challenge |$challenge|\n";
			}

			print $client md5("$challenge . $pass") . "\n";

			my $n = 1;
			my $left = $FREQ;
			do {
				if($left < 0 || $left > $FREQ) { $left = $FREQ; }
				($n, $left) = select(undef, undef, undef, $left);
			} while($n != 0);
		}

		close(NC_IN);
		close(NC_OUT);
	}
}

main();