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<?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) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id: Ntp.php 16209 2009-06-21 19:20:34Z thomas $
*/
/**
* Zend_TimeSync_Protocol
*/
require_once 'Zend/TimeSync/Protocol.php';
/**
* NTP Protocol handling class
*
* @category Zend
* @package Zend_TimeSync
* @copyright Copyright (c) 2005-2009 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;
}
/**
* 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;
}
}
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