#!/usr/bin/perl

use IO::Socket;

#
#	Scan UDP ports
#
$|++;
my @ports = ( 53, 514, 15555 );
scan_udp_ports( 'localhost', \@ports );


sub scan_udp_ports {
	my $host = shift;
	my $ports = shift;

	my($closed, $open, $filtered);

	#	Setup ICMP listen
	my $icmp = IO::Socket::INET->new(
						Proto		=>	'icmp',
						Blocking	=>	0
						) or die("No ICMP listen");

	foreach my $port ( @$ports ) {

		print "Scanning $port\n";

		#	Setup UDP send connection
		$client = IO::Socket::INET->new(
						PeerPort	=>	$port,
						PeerAddr	=>	$host,
						Proto		=>	'udp',
						Blocking	=>	0
						) or die("No server $!");

		#	Send UDP packet
		$client->send( undef );
		sleep( 5 );
		my $icmpbuffer = icmp_recv( $icmp );

		#	Check for response
		my $flags;
		if( $client->recv( $dgram, 10, $flags ) ) {
			print "This udp port $port at host $host responded!\n";
		}
	}
}

sub icmp_recv {
	my $icmp = shift;

	#	Listen for ICMP response
	my $icmpbuffer;
	if( my $icmpr = $icmp->recv( $icmpbuffer, 1024, 0 ) ) {
		print "ICMP Type: " . unpack("%8C", $icmpbuffer) . "\n";
		print "ICMP Code: " . unpack("%8c", substr($icmpbuffer, 9)) . "\n";
		print "ICMP Checksum: " . unpack("%8c", substr($icmpbuffer, 33)) . "\n";
	}
	return $icmpbuffer;
}