<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

/**
 * DNS Library for handling lookups and updates. 
 *
 * PHP Version 5
 *
 * Copyright (c) 2010, Mike Pultz <mike@mikepultz.com>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *
 *   * Neither the name of Mike Pultz nor the names of his contributors 
 *     may be used to endorse or promote products derived from this 
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRIC
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * @category  Networking
 * @package   Net_DNS2
 * @author    Mike Pultz <mike@mikepultz.com>
 * @copyright 2010 Mike Pultz <mike@mikepultz.com>
 * @license   http://www.opensource.org/licenses/bsd-license.php  BSD License
 * @version   SVN: $Id$
 * @link      http://pear.php.net/package/Net_DNS2
 * @since     File available since Release 0.6.0
 *
 */

/**
 * DS Resource Record - RFC4034 sction 5.1
 *
 *    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
 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *   |           Key Tag             |  Algorithm    |  Digest Type  |
 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *   /                                                               /
 *   /                            Digest                             /
 *   /                                                               /
 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * @category Networking
 * @package  Net_DNS2
 * @author   Mike Pultz <mike@mikepultz.com>
 * @license  http://www.opensource.org/licenses/bsd-license.php  BSD License
 * @link     http://pear.php.net/package/Net_DNS2
 * @see      Net_DNS2_RR
 *
 */
class Net_DNS2_RR_DS extends Net_DNS2_RR
{
    /*
     * key tag
     */
    public $keytag;

    /*
     * algorithm number
     */
    public $algorithm;

    /*
     * algorithm used to construct the digest
     */
    public $digesttype;

    /*
     * the digest data
     */
    public $digest;

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

    /**
     * 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)
    {
        $this->keytag       = array_shift($rdata);
        $this->algorithm    = array_shift($rdata);
        $this->digesttype   = array_shift($rdata);
        $this->digest       = implode('', $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 keytag, algorithm and digesttype
            //
            $x = unpack('nkeytag/Calgorithm/Cdigesttype', $this->rdata);

            $this->keytag       = $x['keytag'];
            $this->algorithm    = $x['algorithm'];
            $this->digesttype   = $x['digesttype'];

            //
            // figure out the digest size
            //
            $digest_size = 0;
            if ($this->digesttype == 1) {

                $digest_size = 20; // SHA1

            } else if ($this->digesttype == 2) {

                $digest_size = 32; // SHA256
            }

            //
            // copy the digest
            //
            $x = unpack('H*', substr($this->rdata, 4, $digest_size));
            $this->digest = $x[1];

            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->digest) > 0) {

            $data = pack(
                'nCCH*', 
                $this->keytag, $this->algorithm, $this->digesttype, $this->digest
            );

            $packet->offset += strlen($data);

            return $data;
        }
        
        return null;
    }
}

/*
 * Local variables:
 * tab-width: 4
 * c-basic-offset: 4
 * c-hanging-comment-ender-p: nil
 * End:
 */
?>
