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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: BitMap.php 135 2011-12-04 23:36:07Z mike.pultz $
* @link http://pear.php.net/package/Net_DNS2
* @since File available since Release 0.6.0
*
*/
/**
* a class to handle converting RR bitmaps to arrays and back; used on NSEC
* and NSEC3 RR's
*
* @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_BitMap
{
/**
* parses a RR bitmap field defined in RFC3845, into an array of RR names.
*
* Type Bit Map(s) Field = ( Window Block # | Bitmap Length | Bitmap ) +
*
* @param string $data a bitmap stringto parse
*
* @return array
* @access public
*
*/
public static function bitMapToArray($data)
{
if (strlen($data) == 0) {
return null;
}
$output = array();
$offset = 0;
$length = strlen($data);
while ($offset < $length) {
//
// unpack the window and length values
//
$x = unpack('@' . $offset . '/Cwindow/Clength', $data);
$offset += 2;
//
// copy out the bitmap value
//
$bitmap = unpack('C*', substr($data, $offset, $x['length']));
$offset += $x['length'];
//
// I'm not sure if there's a better way of doing this, but PHP doesn't
// have a 'B' flag for unpack()
//
$bitstr = '';
foreach ($bitmap as $r) {
$bitstr .= sprintf('%08b', $r);
}
$blen = strlen($bitstr);
for ($i=0; $i<$blen; $i++) {
if ($bitstr[$i] == '1') {
$type = $x['window'] * 256 + $i;
if (isset(Net_DNS2_Lookups::$rr_types_by_id[$type])) {
$output[] = Net_DNS2_Lookups::$rr_types_by_id[$type];
} else {
$output[] = 'TYPE' . $type;
}
}
}
}
return $output;
}
/**
* builds a RR Bit map from an array of RR type names
*
* @param array $data a list of RR names
*
* @return string
* @access public
*
*/
public static function arrayToBitMap(array $data)
{
if (count($data) == 0) {
return null;
}
$current_window = 0;
//
// go through each RR
//
$max = 0;
$bm = array();
foreach ($data as $rr) {
$rr = strtoupper($rr);
//
// get the type id for the RR
//
$type = @Net_DNS2_Lookups::$rr_types_by_name[$rr];
if (isset($type)) {
//
// skip meta types or qtypes
//
if ( (isset(Net_DNS2_Lookups::$rr_qtypes_by_id[$type]))
|| (isset(Net_DNS2_Lookups::$rr_metatypes_by_id[$type]))
) {
continue;
}
} else {
//
// if it's not found, then it must be defined as TYPE<id>, per
// RFC3845 section 2.2, if it's not, we ignore it.
//
list($name, $type) = explode('TYPE', $rr);
if (!isset($type)) {
continue;
}
}
//
// build the current window
//
$current_window = (int)($type / 256);
$val = $type - $current_window * 256.0;
if ($val > $max) {
$max = $val;
}
$bm[$current_window][$val] = 1;
$bm[$current_window]['length'] = ceil($max / 8);
}
$output = '';
foreach ($bm as $window => $bitdata) {
$bitstr = '';
for ($i=0; $i<$bm[$window]['length'] * 8; $i++) {
if (isset($bm[$window][$i])) {
$bitstr .= '1';
} else {
$bitstr .= '0';
}
}
$output .= pack('CC', $window, $bm[$window]['length']);
$output .= pack('H*', self::bigBaseConvert($bitstr));
}
return $output;
}
/**
* a base_convert that handles large numbers; forced to 2/16
*
* @param string $number a bit string
*
* @return string
* @access public
*
*/
public static function bigBaseConvert($number)
{
$result = '';
$bin = substr(chunk_split(strrev($number), 4, '-'), 0, -1);
$temp = preg_split('[-]', $bin, -1, PREG_SPLIT_DELIM_CAPTURE);
for ($i = count($temp)-1;$i >= 0;$i--) {
$result = $result . base_convert(strrev($temp[$i]), 2, 16);
}
return strtoupper($result);
}
}
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* c-hanging-comment-ender-p: nil
* End:
*/
?>
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