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<?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: Question.php 124 2011-12-02 23:23:15Z mike.pultz $
* @link http://pear.php.net/package/Net_DNS2
* @since File available since Release 0.6.0
*
*/
/**
* This class handles parsing and constructing the question sectino of DNS
* packets.
*
* This is referred to as the "zone" for update per RFC2136
*
* DNS question format - RFC1035 section 4.1.2
*
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | |
* / QNAME /
* / /
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | QTYPE |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | QCLASS |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
*
* @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_Packet
*
*/
class Net_DNS2_Question
{
/*
* The name of the question
*
* referred to as "zname" for updates per RFC2136
*
*/
public $qname;
/*
* The RR type for the questino
*
* referred to as "ztype" for updates per RFC2136
*
*/
public $qtype;
/*
* The RR class for the questino
*
* referred to as "zclass" for updates per RFC2136
*
*/
public $qclass;
/**
* Constructor - builds a new Net_DNS2_Question object
*
* @param mixed &$packet either a Net_DNS2_Packet object, or null to
* build an empty object
*
* @throws Net_DNS2_Exception
* @access public
*
*/
public function __construct(Net_DNS2_Packet &$packet = null)
{
if (!is_null($packet)) {
$this->set($packet);
} else {
$this->qname = '';
$this->qtype = 'A';
$this->qclass = 'IN';
}
}
/**
* magic __toString() function to return the Net_DNS2_Question object as a string
*
* @return string
* @access public
*
*/
public function __toString()
{
return ";;\n;; Question:\n;;\t " . $this->qname . '. ' .
$this->qtype . ' ' . $this->qclass . "\n";
}
/**
* builds a new Net_DNS2_Header object from a Net_DNS2_Packet object
*
* @param Net_DNS2_Packet &$packet a Net_DNS2_Packet object
*
* @return boolean
* @throws Net_DNS2_Exception
* @access public
*
*/
public function set(Net_DNS2_Packet &$packet)
{
//
// expand the name
//
$this->qname = $packet->expand($packet, $packet->offset);
if ($packet->rdlength < ($packet->offset + 4)) {
throw new Net_DNS2_Exception(
'invalid question section: to small',
Net_DNS2_Lookups::E_QUESTION_INVALID
);
}
//
// unpack the type and class
//
$type = ord($packet->rdata[$packet->offset++]) << 8 |
ord($packet->rdata[$packet->offset++]);
$class = ord($packet->rdata[$packet->offset++]) << 8 |
ord($packet->rdata[$packet->offset++]);
//
// validate it
//
$type_name = Net_DNS2_Lookups::$rr_types_by_id[$type];
$class_name = Net_DNS2_Lookups::$classes_by_id[$class];
if ( (!isset($type_name)) || (!isset($class_name)) ) {
throw new Net_DNS2_Exception(
'invalid question section: invalid type (' . $type .
') or class (' . $class . ') specified.',
Net_DNS2_Lookups::E_QUESTION_INVALID
);
}
//
// store it
//
$this->qtype = $type_name;
$this->qclass = $class_name;
return true;
}
/**
* returns a binary packed Net_DNS2_Question object
*
* @param Net_DNS2_Packet &$packet the Net_DNS2_Packet object this question is
* part of. This needs to be passed in so that
* the compressed qname value can be packed in
* with the names of the other parts of the
* packet.
*
* @return string
* @throws Net_DNS2_Exception
* @access public
*
*/
public function get(Net_DNS2_Packet &$packet)
{
//
// validate the type and class
//
$type = Net_DNS2_Lookups::$rr_types_by_name[$this->qtype];
$class = Net_DNS2_Lookups::$classes_by_name[$this->qclass];
if ( (!isset($type)) || (!isset($class)) ) {
throw new Net_DNS2_Exception(
'invalid question section: invalid type (' . $this->qtype .
') or class (' . $this->qclass . ') specified.',
Net_DNS2_Lookups::E_QUESTION_INVALID
);
}
$data = $packet->compress($this->qname, $packet->offset);
$data .= chr($type << 8) . chr($type) . chr($class << 8) . chr($class);
$packet->offset += 4;
return $data;
}
}
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* c-hanging-comment-ender-p: nil
* End:
*/
?>
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