use Socket;
sub findMask {
	my ($ip, $nets) = @_;

	my ($net, $mask) = ();

	foreach my $i (@$nets) {
		($net, $mask) = split(m[/], $i);

		my $netBin = inet_aton($net);
		my $maskBin = inet_aton($mask);

		my $maskedNet = ($netBin & $maskBin);

		if (((inet_aton($ip)) & $maskBin) eq $maskedNet) {
			return "$mask";
		}
	}

	## no match
	return -1;
}