private function parseCidrRange($range)
    {
        list($address, $mask) = explode('/', $range);
        $longAddress = ip2long($address);
        return array(
            $longAddress & (((1 << $mask) - 1) << (32 - $mask)),
            $longAddress | ((1 << (32 - $mask)) - 1)
        );
    }