/lib/Zend/TimeSync/Ntp.php
PHP | 400 lines | 185 code | 49 blank | 166 comment | 20 complexity | c59d31a3e3bf831a258f0a6c77be21cd MD5 | raw file
- <?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) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
- * @license http://framework.zend.com/license/new-bsd New BSD License
- * @version $Id: Ntp.php 9488 2008-05-19 20:41:34Z thomas $
- */
- /**
- * Zend_TimeSync_Protocol
- */
- require_once 'Zend/TimeSync/Protocol.php';
- /**
- * NTP Protocol handling class
- *
- * @category Zend
- * @package Zend_TimeSync
- * @copyright Copyright (c) 2005-2008 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://' . $timeserver;
- if (is_null($port) === false) {
- $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;
- }
- /**
- * 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' => ord(fread($this->_socket, 4)),
- 'rootdispersion' => ord(fread($this->_socket, 4)),
- 'referenceid' => ord(fread($this->_socket, 4)),
- 'referencestamp' => ord(fread($this->_socket, 4)),
- 'referencemicro' => ord(fread($this->_socket, 4)),
- 'originatestamp' => ord(fread($this->_socket, 4)),
- 'originatemicro' => ord(fread($this->_socket, 4)),
- 'receivestamp' => ord(fread($this->_socket, 4)),
- 'receivemicro' => ord(fread($this->_socket, 4)),
- 'transmitstamp' => ord(fread($this->_socket, 4)),
- 'transmitmicro' => ord(fread($this->_socket, 4)),
- 'clientreceived' => 0
- );
- $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'] >> 15;
- $this->_info['rootdelayfrac'] = ($binary['rootdelay'] << 17) >> 17;
- /*
- * 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'] >> 15;
- $this->_info['rootdispersionfrac'] = ($binary['rootdispersion'] << 17) >> 17;
- /*
- * The local time, in timestamp format, at the peer
- * when its latest NTP message was sent.
- */
- $original = (float) $binary['originatestamp'];
- $original += (float) ($binary['originatemicro'] / 4294967296);
- /*
- * The local time, in timestamp format, when the latest
- * NTP message from the peer arrived.
- */
- $received = (float) $binary['receivestamp'];
- $received += (float) ($binary['receivemicro'] / 4294967296);
- /*
- * The local time, in timestamp format, at which the
- * NTP message departed the sender.
- */
- $transmit = (float) $binary['transmitstamp'];
- $transmit += (float) ($binary['transmitmicro'] / 4294967296);
- /*
- * 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.
- */
- $roundtrip = ($binary['clientreceived'] - $original);
- $roundtrip -= ($transmit - $received);
- $this->_info['roundtrip'] = ($roundtrip / 2);
- // The offset of the peer clock relative to the local clock, in seconds.
- $offset = ($received - $original + $transmit - $binary['clientreceived']);
- $this->_info['offset'] = ($offset / 2);
- $time = (time() - $this->_info['offset']);
- return $time;
- }
- }