define("NET_INVALID_IP",          0x1);
define("NET_INVALID_PORT",        0x2);
define("NET_VALID_IPv4",          0x4);
define("NET_VALID_IPv6",          0x8);
define("NET_VALID_IP_WITH_PORT",  0x10)

/**
 * Validate a port number
 * @param integer $port
 * @return boolean
 */
public static function isValidPort($port) {
    return $port > 0 && $port < 65535;
}

/**
 * Validate an address, and point out if port is part of the address
 * @param string $ip
 * @param integer $port
 * @return string
 */
public static function isValidIp($ip, &$port) {
    // IPv6 with port
    $ipv6_with_port = Array();
    preg_match("/^\[(?P<address>.*?)\]:(?P<port>\d{0,})$/", $ip, $ipv6_with_port);

    // IPv4 with port
    $ipv4_with_port = Array();
    preg_match("/^(?P<address>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}):(?P<port>\d{0,})$/", $ip, $ipv4_with_port);

    if(count($ipv6_with_port) > 0) {
        if(!NET_IPv6::checkIPv6($ipv6_with_port["address"])) {
            return NET_INVALID_IP;
        } else {
            $port = $ipv6_with_port["port"];

            if(ODDNS::isValidPort($ipv6_with_port["port"])) {
                return NET_VALID_IPv6 + ODDNS_VALID_IP_WITH_PORT;
            } else {
                return NET_INVALID_PORT;
            }
        }
    } else if(count($ipv4_with_port) > 0) {
        if(!NET_IPv4::validateIP($ipv4_with_port["address"])) {
            return NET_INVALID_IP;
        } else {
            $port = $ipv4_with_port["port"];

            if(ODDNS::isValidPort($ipv4_with_port["port"])) {
                return NET_VALID_IPv4 + ODDNS_VALID_IP_WITH_PORT;
            } else {
                return NET_INVALID_PORT;
            }
        }
    } else if(preg_match("/^(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})/", $ip) == 1) {
        if(NET_IPv4::validateIP($ip)) {
            return NET_VALID_IPv4;
        }
    } else {
        if(NET_IPv6::checkIPv6($ip)) {
            return NET_VALID_IPv6;
        }
    }

    return NET_INVALID_IP;
}