protected static function cidrMatch64bit($ipAddr, $cidr)
    {
        list ($sn, $bits) = explode('/', $cidr);
        $ipLong = self::ip2long64($ipAddr, $bits);
        $subnet = self::ip2long64($sn, $bits);
        $mask = -1 << (32 - $bits);

        return ($ipLong & $mask) == $subnet;
    }