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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: Header.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
*
*/
/**
* DNS Packet Header class
*
* This class handles parsing and constructing DNS Packet Headers as defined
* by section 4.1.1 of RFC1035.
*
* DNS header format - RFC1035 section 4.1.1
*
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | ID |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* |QR| Opcode |AA|TC|RD|RA| Z | RCODE |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | QDCOUNT |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | ANCOUNT |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | NSCOUNT |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | ARCOUNT |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
*
* @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
*
*/
class Net_DNS2_Header
{
public $id; // 16 bit - identifier
public $qr; // 1 bit - 0 = query, 1 = response
public $opcode; // 4 bit - op code
public $aa; // 1 bit - Authoritative Answer
public $tc; // 1 bit - TrunCation
public $rd; // 1 bit - Recursion Desired
public $ra; // 1 bit - Recursion Available
public $z; // 3 bit - Reserved
public $rcode; // 4 bit - Response code
public $qdcount; // 16 bit - entries in the question section
public $ancount; // 16 bit - resource records in the answer section
public $nscount; // 16 bit - name server rr in the authority records section
public $arcount; // 16 bit - rr's in the additional records section
/**
* Constructor - builds a new Net_DNS2_Header object
*
* @param mixed &$packet either a Net_DNS2_Packet object or null
*
* @throws Net_DNS2_Exception
* @access public
*
*/
public function __construct(Net_DNS2_Packet &$packet = null)
{
if (!is_null($packet)) {
$this->set($packet);
} else {
$this->id = $this->nextPacketId();
$this->qr = Net_DNS2_Lookups::QR_QUERY;
$this->opcode = Net_DNS2_Lookups::OPCODE_QUERY;
$this->aa = 0;
$this->tc = 0;
$this->rd = 1;
$this->ra = 0;
$this->z = 0;
$this->rcode = Net_DNS2_Lookups::RCODE_NOERROR;
$this->qdcount = 1;
$this->ancount = 0;
$this->nscount = 0;
$this->arcount = 0;
}
}
/**
* returns the next available packet id
*
* @return integer
* @access public
*
*/
public function nextPacketId()
{
if (++Net_DNS2_Lookups::$next_packet_id > 65535) {
Net_DNS2_Lookups::$next_packet_id = 1;
}
return Net_DNS2_Lookups::$next_packet_id;
}
/**
* magic __toString() method to return the header as a string
*
* @return string
* @access public
*
*/
public function __toString()
{
$output = ";;\n;; Header:\n";
$output .= ";;\t id = " . $this->id . "\n";
$output .= ";;\t qr = " . $this->qr . "\n";
$output .= ";;\t opcode = " . $this->opcode . "\n";
$output .= ";;\t aa = " . $this->aa . "\n";
$output .= ";;\t tc = " . $this->tc . "\n";
$output .= ";;\t rd = " . $this->rd . "\n";
$output .= ";;\t ra = " . $this->ra . "\n";
$output .= ";;\t z = " . $this->z . "\n";
$output .= ";;\t rcode = " . $this->rcode . "\n";
$output .= ";;\t qdcount = " . $this->qdcount . "\n";
$output .= ";;\t ancount = " . $this->ancount . "\n";
$output .= ";;\t nscount = " . $this->nscount . "\n";
$output .= ";;\t arcount = " . $this->arcount . "\n";
return $output;
}
/**
* constructs a Net_DNS2_Header from a Net_DNS2_Packet object
*
* @param Net_DNS2_Packet &$packet Object
*
* @return boolean
* @throws Net_DNS2_Exception
* @access public
*
*/
public function set(Net_DNS2_Packet &$packet)
{
//
// the header must be at least 12 bytes long.
//
if ($packet->rdlength < Net_DNS2_Lookups::DNS_HEADER_SIZE) {
throw new Net_DNS2_Exception(
'invalid header data provided; to small',
Net_DNS2_Lookups::E_HEADER_INVALID
);
}
$offset = 0;
//
// parse the values
//
$this->id = ord($packet->rdata[$offset]) << 8 |
ord($packet->rdata[++$offset]);
++$offset;
$this->qr = (ord($packet->rdata[$offset]) >> 7) & 0x1;
$this->opcode = (ord($packet->rdata[$offset]) >> 3) & 0xf;
$this->aa = (ord($packet->rdata[$offset]) >> 2) & 0x1;
$this->tc = (ord($packet->rdata[$offset]) >> 1) & 0x1;
$this->rd = ord($packet->rdata[$offset]) & 0x1;
++$offset;
$this->ra = (ord($packet->rdata[$offset]) >> 7) & 0x1;
$this->z = 0;
$this->rcode = ord($packet->rdata[$offset]) & 0xf;
$this->qdcount = ord($packet->rdata[++$offset]) << 8 |
ord($packet->rdata[++$offset]);
$this->ancount = ord($packet->rdata[++$offset]) << 8 |
ord($packet->rdata[++$offset]);
$this->nscount = ord($packet->rdata[++$offset]) << 8 |
ord($packet->rdata[++$offset]);
$this->arcount = ord($packet->rdata[++$offset]) << 8 |
ord($packet->rdata[++$offset]);
//
// increment the internal offset
//
$packet->offset += Net_DNS2_Lookups::DNS_HEADER_SIZE;
return true;
}
/**
* returns a binary packed DNS Header
*
* @param Net_DNS2_Packet &$packet Object
*
* @return string
* @access public
*
*/
public function get(Net_DNS2_Packet &$packet)
{
$data = pack('n', $this->id) .
chr(
($this->qr << 7) | ($this->opcode << 3) |
($this->aa << 2) | ($this->tc << 1) | ($this->rd)
) .
chr(($this->ra << 7) | $this->rcode) .
chr($this->qdcount << 8) . chr($this->qdcount) .
chr($this->ancount << 8) . chr($this->ancount) .
chr($this->nscount << 8) . chr($this->nscount) .
chr($this->arcount << 8) . chr($this->arcount);
$packet->offset += Net_DNS2_Lookups::DNS_HEADER_SIZE;
return $data;
}
}
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* c-hanging-comment-ender-p: nil
* End:
*/
?>
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