zend-framework /TimeSync/Ntp.php

Language PHP Lines 432
MD5 Hash 653724b99113eae673220f9bb2e46fe1 Estimated Cost $5,221 (why?)
Repository https://bitbucket.org/gkawka/zend-framework.git View Raw File View Project SPDX
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category  Zend
 * @package   Zend_TimeSync
 * @copyright  Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd     New BSD License
 * @version   $Id: Ntp.php 24593 2012-01-05 20:35:02Z matthew $
 */

/**
 * Zend_TimeSync_Protocol
 */
require_once 'Zend/TimeSync/Protocol.php';

/**
 * NTP Protocol handling class
 *
 * @category  Zend
 * @package   Zend_TimeSync
 * @copyright  Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_TimeSync_Ntp extends Zend_TimeSync_Protocol
{
    /**
     * NTP port number (123) assigned by the Internet Assigned Numbers Authority
     *
     * @var integer
     */
    protected $_port = 123;

    /**
     * NTP class constructor, sets the timeserver and port number
     *
     * @param string  $timeserver Adress of the timeserver to connect to
     * @param integer $port       (Optional) Port for this timeserver
     */
    public function __construct($timeserver, $port = 123)
    {
        $this->_timeserver = 'udp://' . $timeserver;
        if ($port !== null) {
            $this->_port = $port;
        }
    }

    /**
     * Prepare local timestamp for transmission in our request packet
     *
     * NTP timestamps are represented as a 64-bit fixed-point number, in
     * seconds relative to 0000 UT on 1 January 1900.  The integer part is
     * in the first 32 bits and the fraction part in the last 32 bits
     *
     * @return string
     */
    protected function _prepare()
    {
        $frac   = microtime();
        $fracba = ($frac & 0xff000000) >> 24;
        $fracbb = ($frac & 0x00ff0000) >> 16;
        $fracbc = ($frac & 0x0000ff00) >> 8;
        $fracbd = ($frac & 0x000000ff);

        $sec   = (time() + 2208988800);
        $secba = ($sec & 0xff000000) >> 24;
        $secbb = ($sec & 0x00ff0000) >> 16;
        $secbc = ($sec & 0x0000ff00) >> 8;
        $secbd = ($sec & 0x000000ff);

        // Flags
        $nul       = chr(0x00);
        $nulbyte   = $nul . $nul . $nul . $nul;
        $ntppacket = chr(0xd9) . $nul . chr(0x0a) . chr(0xfa);

        /*
         * Root delay
         *
         * Indicates the total roundtrip delay to the primary reference
         * source at the root of the synchronization subnet, in seconds
         */
        $ntppacket .= $nul . $nul . chr(0x1c) . chr(0x9b);

        /*
         * Clock Dispersion
         *
         * Indicates the maximum error relative to the primary reference source at the
         * root of the synchronization subnet, in seconds
         */
        $ntppacket .= $nul . chr(0x08) . chr(0xd7) . chr(0xff);

        /*
         * ReferenceClockID
         *
         * Identifying the particular reference clock
         */
        $ntppacket .= $nulbyte;

        /*
         * The local time, in timestamp format, at the peer when its latest NTP message
         * was sent. Contanis an integer and a fractional part
         */
        $ntppacket .= chr($secba)  . chr($secbb)  . chr($secbc)  . chr($secbd);
        $ntppacket .= chr($fracba) . chr($fracbb) . chr($fracbc) . chr($fracbd);

        /*
         * The local time, in timestamp format, at the peer. Contains an integer
         * and a fractional part.
         */
        $ntppacket .= $nulbyte;
        $ntppacket .= $nulbyte;

        /*
         * This is the local time, in timestamp format, when the latest NTP message from
         * the peer arrived. Contanis an integer and a fractional part.
         */
        $ntppacket .= $nulbyte;
        $ntppacket .= $nulbyte;

        /*
         * The local time, in timestamp format, at which the
         * NTP message departed the sender. Contanis an integer
         * and a fractional part.
         */
        $ntppacket .= chr($secba)  . chr($secbb)  . chr($secbc)  . chr($secbd);
        $ntppacket .= chr($fracba) . chr($fracbb) . chr($fracbc) . chr($fracbd);

        return $ntppacket;
    }

    /**
     * Calculates a 32bit integer
     *
     * @param string $input
     * @return integer
     */
    protected function _getInteger($input)
    {
        $f1  = str_pad(ord($input[0]), 2, '0', STR_PAD_LEFT);
        $f1 .= str_pad(ord($input[1]), 2, '0', STR_PAD_LEFT);
        $f1 .= str_pad(ord($input[2]), 2, '0', STR_PAD_LEFT);
        $f1 .= str_pad(ord($input[3]), 2, '0', STR_PAD_LEFT);
        return (int) $f1;
    }

    /**
     * Calculates a 32bit signed fixed point number
     *
     * @param string $input
     * @return float
     */
    protected function _getFloat($input)
    {
        $f1  = str_pad(ord($input[0]), 2, '0', STR_PAD_LEFT);
        $f1 .= str_pad(ord($input[1]), 2, '0', STR_PAD_LEFT);
        $f1 .= str_pad(ord($input[2]), 2, '0', STR_PAD_LEFT);
        $f1 .= str_pad(ord($input[3]), 2, '0', STR_PAD_LEFT);
        $f2  = $f1 >> 17;
        $f3  = ($f1 & 0x0001FFFF);
        $f1  = $f2 . '.' . $f3;
        return (float) $f1;
    }

    /**
     * Calculates a 64bit timestamp
     *
     * @param string $input
     * @return float
     */
    protected function _getTimestamp($input)
    {
        $f1  = (ord($input[0]) * pow(256, 3));
        $f1 += (ord($input[1]) * pow(256, 2));
        $f1 += (ord($input[2]) * pow(256, 1));
        $f1 += (ord($input[3]));
        $f1 -= 2208988800;

        $f2  = (ord($input[4]) * pow(256, 3));
        $f2 += (ord($input[5]) * pow(256, 2));
        $f2 += (ord($input[6]) * pow(256, 1));
        $f2 += (ord($input[7]));

        return (float) ($f1 . "." . $f2);
    }

    /**
     * Reads the data returned from the timeserver
     *
     * This will return an array with binary data listing:
     *
     * @return array
     * @throws Zend_TimeSync_Exception When timeserver can not be connected
     */
    protected function _read()
    {
        $flags = ord(fread($this->_socket, 1));
        $info  = stream_get_meta_data($this->_socket);

        if ($info['timed_out'] === true) {
            fclose($this->_socket);
            throw new Zend_TimeSync_Exception('could not connect to ' .
                "'$this->_timeserver' on port '$this->_port', reason: 'server timed out'");
        }

        $result = array(
            'flags'          => $flags,
            'stratum'        => ord(fread($this->_socket, 1)),
            'poll'           => ord(fread($this->_socket, 1)),
            'precision'      => ord(fread($this->_socket, 1)),
            'rootdelay'      => $this->_getFloat(fread($this->_socket, 4)),
            'rootdispersion' => $this->_getFloat(fread($this->_socket, 4)),
            'referenceid'    => fread($this->_socket, 4),
            'referencestamp' => $this->_getTimestamp(fread($this->_socket, 8)),
            'originatestamp' => $this->_getTimestamp(fread($this->_socket, 8)),
            'receivestamp'   => $this->_getTimestamp(fread($this->_socket, 8)),
            'transmitstamp'  => $this->_getTimestamp(fread($this->_socket, 8)),
            'clientreceived' => microtime(true)
        );

        $this->_disconnect();
        return $result;
    }

    /**
     * Sends the NTP packet to the server
     *
     * @param  string $data Data to send to the timeserver
     * @return void
     */
    protected function _write($data)
    {
        $this->_connect();

        fwrite($this->_socket, $data);
        stream_set_timeout($this->_socket, Zend_TimeSync::$options['timeout']);
    }

    /**
     * Extracts the binary data returned from the timeserver
     *
     * @param  string|array $binary Data returned from the timeserver
     * @return integer Difference in seconds
     */
    protected function _extract($binary)
    {
        /*
         * Leap Indicator bit 1100 0000
         *
         * Code warning of impending leap-second to be inserted at the end of
         * the last day of the current month.
         */
        $leap = ($binary['flags'] & 0xc0) >> 6;
        switch($leap) {
            case 0:
                $this->_info['leap'] = '0 - no warning';
                break;

            case 1:
                $this->_info['leap'] = '1 - last minute has 61 seconds';
                break;

            case 2:
                $this->_info['leap'] = '2 - last minute has 59 seconds';
                break;

            default:
                $this->_info['leap'] = '3 - not syncronised';
                break;
        }

        /*
         * Version Number bit 0011 1000
         *
         * This should be 3 (RFC 1305)
         */
        $this->_info['version'] = ($binary['flags'] & 0x38) >> 3;

        /*
         * Mode bit 0000 0111
         *
         * Except in broadcast mode, an NTP association is formed when two peers
         * exchange messages and one or both of them create and maintain an
         * instantiation of the protocol machine, called an association.
         */
        $mode = ($binary['flags'] & 0x07);
        switch($mode) {
            case 1:
                $this->_info['mode'] = 'symetric active';
                break;

            case 2:
                $this->_info['mode'] = 'symetric passive';
                break;

            case 3:
                $this->_info['mode'] = 'client';
                break;

            case 4:
                $this->_info['mode'] = 'server';
                break;

            case 5:
                $this->_info['mode'] = 'broadcast';
                break;

            default:
                $this->_info['mode'] = 'reserved';
                break;
        }

        $ntpserviceid = 'Unknown Stratum ' . $binary['stratum'] . ' Service';

        /*
         * Reference Clock Identifier
         *
         * Identifies the particular reference clock.
         */
        $refid = strtoupper($binary['referenceid']);
        switch($binary['stratum']) {
            case 0:
                if (substr($refid, 0, 3) === 'DCN') {
                    $ntpserviceid = 'DCN routing protocol';
                } else if (substr($refid, 0, 4) === 'NIST') {
                    $ntpserviceid = 'NIST public modem';
                } else if (substr($refid, 0, 3) === 'TSP') {
                    $ntpserviceid = 'TSP time protocol';
                } else if (substr($refid, 0, 3) === 'DTS') {
                    $ntpserviceid = 'Digital Time Service';
                }
                break;

            case 1:
                if (substr($refid, 0, 4) === 'ATOM') {
                    $ntpserviceid = 'Atomic Clock (calibrated)';
                } else if (substr($refid, 0, 3) === 'VLF') {
                    $ntpserviceid = 'VLF radio';
                } else if ($refid === 'CALLSIGN') {
                    $ntpserviceid = 'Generic radio';
                } else if (substr($refid, 0, 4) === 'LORC') {
                    $ntpserviceid = 'LORAN-C radionavigation';
                } else if (substr($refid, 0, 4) === 'GOES') {
                    $ntpserviceid = 'GOES UHF environment satellite';
                } else if (substr($refid, 0, 3) === 'GPS') {
                    $ntpserviceid = 'GPS UHF satellite positioning';
                }
                break;

            default:
                $ntpserviceid  = ord(substr($binary['referenceid'], 0, 1));
                $ntpserviceid .= '.';
                $ntpserviceid .= ord(substr($binary['referenceid'], 1, 1));
                $ntpserviceid .= '.';
                $ntpserviceid .= ord(substr($binary['referenceid'], 2, 1));
                $ntpserviceid .= '.';
                $ntpserviceid .= ord(substr($binary['referenceid'], 3, 1));
                break;
        }

        $this->_info['ntpid'] = $ntpserviceid;

        /*
         * Stratum
         *
         * Indicates the stratum level of the local clock
         */
        switch($binary['stratum']) {
            case 0:
                $this->_info['stratum'] = 'undefined';
                break;

            case 1:
                $this->_info['stratum'] = 'primary reference';
                break;

            default:
                $this->_info['stratum'] = 'secondary reference';
                break;
        }

        /*
         * Indicates the total roundtrip delay to the primary reference source at the
         * root of the synchronization subnet, in seconds.
         *
         * Both positive and negative values, depending on clock precision and skew, are
         * possible.
         */
        $this->_info['rootdelay'] = $binary['rootdelay'];

        /*
         * Indicates the maximum error relative to the primary reference source at the
         * root of the synchronization subnet, in seconds.
         *
         * Only positive values greater than zero are possible.
         */
        $this->_info['rootdispersion'] = $binary['rootdispersion'];

        /*
         * The roundtrip delay of the peer clock relative to the local clock
         * over the network path between them, in seconds.
         *
         * Note that this variable can take on both positive and negative values,
         * depending on clock precision and skew-error accumulation.
         */
        $this->_info['roundtrip']  = $binary['receivestamp'];
        $this->_info['roundtrip'] -= $binary['originatestamp'];
        $this->_info['roundtrip'] -= $binary['transmitstamp'];
        $this->_info['roundtrip'] += $binary['clientreceived'];
        $this->_info['roundtrip'] /= 2;

        // The offset of the peer clock relative to the local clock, in seconds.
        $this->_info['offset']  = $binary['receivestamp'];
        $this->_info['offset'] -= $binary['originatestamp'];
        $this->_info['offset'] += $binary['transmitstamp'];
        $this->_info['offset'] -= $binary['clientreceived'];
        $this->_info['offset'] /= 2;
        $time = (time() - $this->_info['offset']);

        return $time;
    }
}
Back to Top