<?php

/**
 * DNS Library for handling lookups and updates. 
 *
 * Copyright (c) 2020, Mike Pultz <mike@mikepultz.com>. All rights reserved.
 *
 * See LICENSE for more details.
 *
 * @category  Networking
 * @package   Net_DNS2
 * @author    Mike Pultz <mike@mikepultz.com>
 * @copyright 2020 Mike Pultz <mike@mikepultz.com>
 * @license   http://www.opensource.org/licenses/bsd-license.php  BSD License
 * @link      https://netdns2.com/
 * @since     File available since Release 1.3.1
 *
 */

/**
 * NID Resource Record - RFC6742 section 2.1
 *
 *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |          Preference           |                               |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
 *  |                             NodeID                            |
 *  +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |                               |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 */
class Net_DNS2_RR_NID extends Net_DNS2_RR
{
    /*
     * The preference
     */
    public $preference;

    /*
     * The node ID field
     */
    public $nodeid;

    /**
     * method to return the rdata portion of the packet as a string
     *
     * @return  string
     * @access  protected
     *
     */
    protected function rrToString()
    {
        return $this->preference . ' ' . $this->nodeid;
    }

    /**
     * parses the rdata portion from a standard DNS config line
     *
     * @param array $rdata a string split line of values for the rdata
     *
     * @return boolean
     * @access protected
     *
     */
    protected function rrFromString(array $rdata)
    {
        $this->preference = array_shift($rdata);
        $this->nodeid = array_shift($rdata);

        return true;
    }

    /**
     * parses the rdata of the Net_DNS2_Packet object
     *
     * @param Net_DNS2_Packet &$packet a Net_DNS2_Packet packet to parse the RR from
     *
     * @return boolean
     * @access protected
     * 
     */
    protected function rrSet(Net_DNS2_Packet &$packet)
    {
        if ($this->rdlength > 0) {
        
            //
            // unpack the values
            //
            $x = unpack('npreference/n4nodeid', $this->rdata);

            $this->preference = $x['preference'];

            //
            // build the node id
            //
            $this->nodeid = dechex($x['nodeid1']) . ':' . 
                dechex($x['nodeid2']) . ':' .
                dechex($x['nodeid3']) . ':' . 
                dechex($x['nodeid4']);

            return true;
        }

        return false;
    }

    /**
     * returns the rdata portion of the DNS packet
     * 
     * @param Net_DNS2_Packet &$packet a Net_DNS2_Packet packet use for
     *                                 compressed names
     *
     * @return mixed                   either returns a binary packed 
     *                                 string or null on failure
     * @access protected
     * 
     */
    protected function rrGet(Net_DNS2_Packet &$packet)
    {
        if (strlen($this->nodeid) > 0) {

            //
            // break out the node id
            //
            $n = explode(':', $this->nodeid);

            //
            // pack the data
            //
            return pack(
                'n5', $this->preference, hexdec($n[0]), hexdec($n[1]), 
                hexdec($n[2]), hexdec($n[3])
            );
        }

        return null;
    }
}