1<?php
2/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
3
4/**
5 * DNS Library for handling lookups and updates.
6 *
7 * PHP Version 5
8 *
9 * Copyright (c) 2010, Mike Pultz <mike@mikepultz.com>.
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 *
16 *   * Redistributions of source code must retain the above copyright
17 *     notice, this list of conditions and the following disclaimer.
18 *
19 *   * Redistributions in binary form must reproduce the above copyright
20 *     notice, this list of conditions and the following disclaimer in
21 *     the documentation and/or other materials provided with the
22 *     distribution.
23 *
24 *   * Neither the name of Mike Pultz nor the names of his contributors
25 *     may be used to endorse or promote products derived from this
26 *     software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
31 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
32 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
34 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
35 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
36 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRIC
37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
38 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
39 * POSSIBILITY OF SUCH DAMAGE.
40 *
41 * @category  Networking
42 * @package   Net_DNS2
43 * @author    Mike Pultz <mike@mikepultz.com>
44 * @copyright 2010 Mike Pultz <mike@mikepultz.com>
45 * @license   http://www.opensource.org/licenses/bsd-license.php  BSD License
46 * @version   SVN: $Id$
47 * @link      http://pear.php.net/package/Net_DNS2
48 * @since     File available since Release 0.6.0
49 *
50 */
51
52/**
53 * a class to handle converting RR bitmaps to arrays and back; used on NSEC
54 * and NSEC3 RR's
55 *
56 * @category Networking
57 * @package  Net_DNS2
58 * @author   Mike Pultz <mike@mikepultz.com>
59 * @license  http://www.opensource.org/licenses/bsd-license.php  BSD License
60 * @link     http://pear.php.net/package/Net_DNS2
61 * @see      Net_DNS2_Packet
62 *
63 */
64class Net_DNS2_BitMap
65{
66    /**
67     * parses a RR bitmap field defined in RFC3845, into an array of RR names.
68     *
69     * Type Bit Map(s) Field = ( Window Block # | Bitmap Length | Bitmap ) +
70     *
71     * @param string $data a bitmap stringto parse
72     *
73     * @return array
74     * @access public
75     *
76     */
77    public static function bitMapToArray($data)
78    {
79        if (strlen($data) == 0) {
80            return array();
81        }
82
83        $output = array();
84        $offset = 0;
85        $length = strlen($data);
86
87        while ($offset < $length) {
88
89            //
90            // unpack the window and length values
91            //
92            $x = unpack('@' . $offset . '/Cwindow/Clength', $data);
93            $offset += 2;
94
95            //
96            // copy out the bitmap value
97            //
98            $bitmap = unpack('C*', substr($data, $offset, $x['length']));
99            $offset += $x['length'];
100
101            //
102            // I'm not sure if there's a better way of doing this, but PHP doesn't
103            // have a 'B' flag for unpack()
104            //
105            $bitstr = '';
106            foreach ($bitmap as $r) {
107
108                $bitstr .= sprintf('%08b', $r);
109            }
110
111            $blen = strlen($bitstr);
112            for ($i=0; $i<$blen; $i++) {
113
114                if ($bitstr[$i] == '1') {
115
116                    $type = $x['window'] * 256 + $i;
117
118                    if (isset(Net_DNS2_Lookups::$rr_types_by_id[$type])) {
119
120                        $output[] = Net_DNS2_Lookups::$rr_types_by_id[$type];
121                    } else {
122
123                        $output[] = 'TYPE' . $type;
124                    }
125                }
126            }
127        }
128
129        return $output;
130    }
131
132    /**
133     * builds a RR Bit map from an array of RR type names
134     *
135     * @param array $data a list of RR names
136     *
137     * @return string
138     * @access public
139     *
140     */
141    public static function arrayToBitMap(array $data)
142    {
143        if (count($data) == 0) {
144            return '';
145        }
146
147        $current_window = 0;
148
149        //
150        // go through each RR
151        //
152        $max = 0;
153        $bm = array();
154
155        foreach ($data as $rr) {
156
157            $rr = strtoupper($rr);
158
159            //
160            // get the type id for the RR
161            //
162            $type = @Net_DNS2_Lookups::$rr_types_by_name[$rr];
163            if (isset($type)) {
164
165                //
166                // skip meta types or qtypes
167                //
168                if ( (isset(Net_DNS2_Lookups::$rr_qtypes_by_id[$type]))
169                    || (isset(Net_DNS2_Lookups::$rr_metatypes_by_id[$type]))
170                ) {
171                    continue;
172                }
173
174            } else {
175
176                //
177                // if it's not found, then it must be defined as TYPE<id>, per
178                // RFC3845 section 2.2, if it's not, we ignore it.
179                //
180                list($name, $type) = explode('TYPE', $rr);
181                if (!isset($type)) {
182
183                    continue;
184                }
185            }
186
187            //
188            // build the current window
189            //
190            $current_window = (int)($type / 256);
191
192            $val = $type - $current_window * 256.0;
193            if ($val > $max) {
194                $max = $val;
195            }
196
197            $bm[$current_window][$val] = 1;
198            $bm[$current_window]['length'] = ceil(($max + 1) / 8);
199        }
200
201        $output = '';
202
203        foreach ($bm as $window => $bitdata) {
204
205            $bitstr = '';
206
207            for ($i=0; $i<$bm[$window]['length'] * 8; $i++) {
208                if (isset($bm[$window][$i])) {
209                    $bitstr .= '1';
210                } else {
211                    $bitstr .= '0';
212                }
213            }
214
215            $output .= pack('CC', $window, $bm[$window]['length']);
216            $output .= pack('H*', self::bigBaseConvert($bitstr));
217        }
218
219        return $output;
220    }
221
222    /**
223     * a base_convert that handles large numbers; forced to 2/16
224     *
225     * @param string $number a bit string
226     *
227     * @return string
228     * @access public
229     *
230     */
231    public static function bigBaseConvert($number)
232    {
233        $result = '';
234
235        $bin = substr(chunk_split(strrev($number), 4, '-'), 0, -1);
236        $temp = preg_split('[-]', $bin, -1, PREG_SPLIT_DELIM_CAPTURE);
237
238        for ($i = count($temp)-1;$i >= 0;$i--) {
239
240            $result = $result . base_convert(strrev($temp[$i]), 2, 16);
241        }
242
243        return strtoupper($result);
244    }
245}
246
247/*
248 * Local variables:
249 * tab-width: 4
250 * c-basic-offset: 4
251 * c-hanging-comment-ender-p: nil
252 * End:
253 */
254?>
255