59 lines
1.8 KiB
PHP
59 lines
1.8 KiB
PHP
<?php
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declare(strict_types=1);
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namespace RobThree\Auth\Providers\Time;
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use Exception;
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use function socket_create;
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/**
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* Takes the time from any NTP server
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*/
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class NTPTimeProvider implements ITimeProvider
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{
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public function __construct(public string $host = 'time.google.com', public int $port = 123, public int $timeout = 1)
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{
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if ($this->port <= 0 || $this->port > 65535) {
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throw new TimeException('Port must be 0 < port < 65535');
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}
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if ($this->timeout < 0) {
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throw new TimeException('Timeout must be >= 0');
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}
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}
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/**
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* {@inheritdoc}
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*/
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public function getTime()
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{
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try {
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// Create a socket and connect to NTP server
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$sock = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
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socket_set_option($sock, SOL_SOCKET, SO_RCVTIMEO, array('sec' => $this->timeout, 'usec' => 0));
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socket_connect($sock, $this->host, $this->port);
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// Send request
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$msg = "\010" . str_repeat("\0", 47);
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socket_send($sock, $msg, strlen($msg), 0);
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// Receive response and close socket
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if (socket_recv($sock, $recv, 48, MSG_WAITALL) === false) {
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throw new Exception(socket_strerror(socket_last_error($sock)));
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}
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socket_close($sock);
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// Interpret response
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$data = unpack('N12', $recv);
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$timestamp = (int)sprintf('%u', $data[9]);
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// NTP is number of seconds since 0000 UT on 1 January 1900 Unix time is seconds since 0000 UT on 1 January 1970
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return $timestamp - 2208988800;
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} catch (Exception $ex) {
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throw new TimeException(sprintf('Unable to retrieve time from %s (%s)', $this->host, $ex->getMessage()));
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}
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}
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}
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