hestiacp/web/inc/2fa/Providers/Time/NTPTimeProvider.php

<?php

namespace RobThree\Auth\Providers\Time;

/**
 * Takes the time from any NTP server
 */
class NTPTimeProvider implements ITimeProvider {
	/** @var string */
	public $host;

	/** @var int */
	public $port;

	/** @var int */
	public $timeout;

	/**
	 * @param string $host
	 * @param int $port
	 * @param int $timeout
	 */
	public function __construct($host = "time.google.com", $port = 123, $timeout = 1) {
		$this->host = $host;

		if (!is_int($port) || $port <= 0 || $port > 65535) {
			throw new TimeException("Port must be 0 < port < 65535");
		}
		$this->port = $port;

		if (!is_int($timeout) || $timeout < 0) {
			throw new TimeException("Timeout must be >= 0");
		}
		$this->timeout = $timeout;
	}

	/**
	 * {@inheritdoc}
	 */
	public function getTime() {
		try {
			/* Create a socket and connect to NTP server */
			$sock = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
			socket_set_option($sock, SOL_SOCKET, SO_RCVTIMEO, [
				"sec" => $this->timeout,
				"usec" => 0,
			]);
			socket_connect($sock, $this->host, $this->port);

			/* Send request */
			$msg = "\010" . str_repeat("\0", 47);
			socket_send($sock, $msg, strlen($msg), 0);

			/* Receive response and close socket */
			if (socket_recv($sock, $recv, 48, MSG_WAITALL) === false) {
				throw new \Exception(socket_strerror(socket_last_error($sock)));
			}
			socket_close($sock);

			/* Interpret response */
			$data = unpack("N12", $recv);
			$timestamp = (int) sprintf("%u", $data[9]);

			/* NTP is number of seconds since 0000 UT on 1 January 1900 Unix time is seconds since 0000 UT on 1 January 1970 */
			return $timestamp - 2208988800;
		} catch (\Exception $ex) {
			throw new TimeException(
				sprintf("Unable to retrieve time from %s (%s)", $this->host, $ex->getMessage()),
			);
		}
	}
}