Port and protocol PHP classes draft

ip.php

<?php declare(strict_types=1);

/**
 * Protocol numbers by IANA (Internet Assigned Numbers Authority)
 *
 * Source https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml
 */
abstract class Protocol {
    const UNDEFINED = -1;
    const TCP = 6;
    const UDP = 17;

    static function fromString(string $protocol) : int {
        if (strncmp($protocol, 'tcp', 3)) {
            return Protocol::TCP;
        }
        if (strncmp($protocol, 'udp', 3)) {
            return Protocol::UDP;
        }
        return Protocol::UNDEFINED;
    }
}

class Port {
    const UNDEFINED_PORT = 0;
    /**
     * Port value
     *
     * @var integer
     */
    public $port = self::UNDEFINED_PORT;
    /**
     * Protocol number, one of Protocol:: values.
     *
     * @var integer
     */
    public $protocol = Protocol::UNDEFINED;

    function __construct(int $port, int $protocol) {
        $this->port = $port;
        $this->protocol = $protocol;
    }
}