Wie frage ich einen NTP-Server mit C # ab?

Ich benötige lediglich eine Möglichkeit, einen NTP-Server mit C # abzufragen, um die Datums- und Uhrzeitangabe des NTP-Servers als a stringoder als zurückzugeben DateTime.

Wie ist das in seiner einfachsten Form möglich?

Da die alte akzeptierte Antwort gelöscht wurde (es war ein Link zu einem Google-Code-Suchergebnis, der nicht mehr existiert), dachte ich, ich könnte diese Frage als zukünftige Referenz beantworten:

public static DateTime GetNetworkTime()
{
    //default Windows time server
    const string ntpServer = "time.windows.com";

    // NTP message size - 16 bytes of the digest (RFC 2030)
    var ntpData = new byte[48];

    //Setting the Leap Indicator, Version Number and Mode values
    ntpData[0] = 0x1B; //LI = 0 (no warning), VN = 3 (IPv4 only), Mode = 3 (Client Mode)

    var addresses = Dns.GetHostEntry(ntpServer).AddressList;

    //The UDP port number assigned to NTP is 123
    var ipEndPoint = new IPEndPoint(addresses[0], 123);
    //NTP uses UDP

    using(var socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp))
    {
        socket.Connect(ipEndPoint);

        //Stops code hang if NTP is blocked
        socket.ReceiveTimeout = 3000;     

        socket.Send(ntpData);
        socket.Receive(ntpData);
        socket.Close();
    }

    //Offset to get to the "Transmit Timestamp" field (time at which the reply 
    //departed the server for the client, in 64-bit timestamp format."
    const byte serverReplyTime = 40;

    //Get the seconds part
    ulong intPart = BitConverter.ToUInt32(ntpData, serverReplyTime);

    //Get the seconds fraction
    ulong fractPart = BitConverter.ToUInt32(ntpData, serverReplyTime + 4);

    //Convert From big-endian to little-endian
    intPart = SwapEndianness(intPart);
    fractPart = SwapEndianness(fractPart);

    var milliseconds = (intPart * 1000) + ((fractPart * 1000) / 0x100000000L);

    //**UTC** time
    var networkDateTime = (new DateTime(1900, 1, 1, 0, 0, 0, DateTimeKind.Utc)).AddMilliseconds((long)milliseconds);

    return networkDateTime.ToLocalTime();
}

// stackoverflow.com/a/3294698/162671
static uint SwapEndianness(ulong x)
{
    return (uint) (((x & 0x000000ff) << 24) +
                   ((x & 0x0000ff00) << 8) +
                   ((x & 0x00ff0000) >> 8) +
                   ((x & 0xff000000) >> 24));
}

Hinweis: Sie müssen die folgenden Namespaces hinzufügen

using System.Net;
using System.Net.Sockets;

Dies ist eine optimierte Version der Funktion, die die Abhängigkeit von der BitConverter-Funktion beseitigt und sie mit NETMF (.NET Micro Framework) kompatibel macht.

public static DateTime GetNetworkTime()
{
    const string ntpServer = "pool.ntp.org";
    var ntpData = new byte[48];
    ntpData[0] = 0x1B; //LeapIndicator = 0 (no warning), VersionNum = 3 (IPv4 only), Mode = 3 (Client Mode)

    var addresses = Dns.GetHostEntry(ntpServer).AddressList;
    var ipEndPoint = new IPEndPoint(addresses[0], 123);
    var socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

    socket.Connect(ipEndPoint);
    socket.Send(ntpData);
    socket.Receive(ntpData);
    socket.Close();

    ulong intPart = (ulong)ntpData[40] << 24 | (ulong)ntpData[41] << 16 | (ulong)ntpData[42] << 8 | (ulong)ntpData[43];
    ulong fractPart = (ulong)ntpData[44] << 24 | (ulong)ntpData[45] << 16 | (ulong)ntpData[46] << 8 | (ulong)ntpData[47];

    var milliseconds = (intPart * 1000) + ((fractPart * 1000) / 0x100000000L);
    var networkDateTime = (new DateTime(1900, 1, 1)).AddMilliseconds((long)milliseconds);

    return networkDateTime;
}

Das im CodePlex enthaltene .NET Micro Framework Toolkit verfügt über eine NTPClient. Ich habe es selbst nie benutzt, aber es sieht gut aus.

Es gibt auch ein weiteres Beispiel befindet sich hier .

Ich weiß, dass das Thema ziemlich alt ist, aber solche Tools sind immer praktisch. Ich habe die oben genannten Ressourcen verwendet und eine Version von NtpClient erstellt, mit der asynchron statt ereignisbasiert die genaue Zeit erfasst werden kann.

 /// <summary>
/// Represents a client which can obtain accurate time via NTP protocol.
/// </summary>
public class NtpClient
{
    private readonly TaskCompletionSource<DateTime> _resultCompletionSource;

    /// <summary>
    /// Creates a new instance of <see cref="NtpClient"/> class.
    /// </summary>
    public NtpClient()
    {
        _resultCompletionSource = new TaskCompletionSource<DateTime>();
    }

    /// <summary>
    /// Gets accurate time using the NTP protocol with default timeout of 45 seconds.
    /// </summary>
    /// <returns>Network accurate <see cref="DateTime"/> value.</returns>
    public async Task<DateTime> GetNetworkTimeAsync()
    {
        return await GetNetworkTimeAsync(TimeSpan.FromSeconds(45));
    }

    /// <summary>
    /// Gets accurate time using the NTP protocol with default timeout of 45 seconds.
    /// </summary>
    /// <param name="timeoutMs">Operation timeout in milliseconds.</param>
    /// <returns>Network accurate <see cref="DateTime"/> value.</returns>
    public async Task<DateTime> GetNetworkTimeAsync(int timeoutMs)
    {
        return await GetNetworkTimeAsync(TimeSpan.FromMilliseconds(timeoutMs));
    }

    /// <summary>
    /// Gets accurate time using the NTP protocol with default timeout of 45 seconds.
    /// </summary>
    /// <param name="timeout">Operation timeout.</param>
    /// <returns>Network accurate <see cref="DateTime"/> value.</returns>
    public async Task<DateTime> GetNetworkTimeAsync(TimeSpan timeout)
    {
        using (var socket = new DatagramSocket())
        using (var ct = new CancellationTokenSource(timeout))
        {
            ct.Token.Register(() => _resultCompletionSource.TrySetCanceled());

            socket.MessageReceived += OnSocketMessageReceived;
            //The UDP port number assigned to NTP is 123
            await socket.ConnectAsync(new HostName("pool.ntp.org"), "123");
            using (var writer = new DataWriter(socket.OutputStream))
            {
                // NTP message size is 16 bytes of the digest (RFC 2030)
                var ntpBuffer = new byte[48];

                // Setting the Leap Indicator, 
                // Version Number and Mode values
                // LI = 0 (no warning)
                // VN = 3 (IPv4 only)
                // Mode = 3 (Client Mode)
                ntpBuffer[0] = 0x1B;

                writer.WriteBytes(ntpBuffer);
                await writer.StoreAsync();
                var result = await _resultCompletionSource.Task;
                return result;
            }
        }
    }

    private void OnSocketMessageReceived(DatagramSocket sender, DatagramSocketMessageReceivedEventArgs args)
    {
        try
        {
            using (var reader = args.GetDataReader())
            {
                byte[] response = new byte[48];
                reader.ReadBytes(response);
                _resultCompletionSource.TrySetResult(ParseNetworkTime(response));
            }
        }
        catch (Exception ex)
        {
            _resultCompletionSource.TrySetException(ex);
        }
    }

    private static DateTime ParseNetworkTime(byte[] rawData)
    {
        //Offset to get to the "Transmit Timestamp" field (time at which the reply 
        //departed the server for the client, in 64-bit timestamp format."
        const byte serverReplyTime = 40;

        //Get the seconds part
        ulong intPart = BitConverter.ToUInt32(rawData, serverReplyTime);

        //Get the seconds fraction
        ulong fractPart = BitConverter.ToUInt32(rawData, serverReplyTime + 4);

        //Convert From big-endian to little-endian
        intPart = SwapEndianness(intPart);
        fractPart = SwapEndianness(fractPart);

        var milliseconds = (intPart * 1000) + ((fractPart * 1000) / 0x100000000L);

        //**UTC** time
        DateTime networkDateTime = (new DateTime(1900, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc)).AddMilliseconds((long)milliseconds);
        return networkDateTime;
    }

    // stackoverflow.com/a/3294698/162671
    private static uint SwapEndianness(ulong x)
    {
        return (uint)(((x & 0x000000ff) << 24) +
                       ((x & 0x0000ff00) << 8) +
                       ((x & 0x00ff0000) >> 8) +
                       ((x & 0xff000000) >> 24));
    }
}

Verwendung:

var ntp = new NtpClient();
var accurateTime = await ntp.GetNetworkTimeAsync(TimeSpan.FromSeconds(10));

Eine modifizierte Version zum Kompensieren von Netzwerkzeiten und Berechnen mit DateTime-Ticks (genauer als Millisekunden)

public static DateTime GetNetworkTime()
{
  const string NtpServer = "pool.ntp.org";

  const int DaysTo1900 = 1900 * 365 + 95; // 95 = offset for leap-years etc.
  const long TicksPerSecond = 10000000L;
  const long TicksPerDay = 24 * 60 * 60 * TicksPerSecond;
  const long TicksTo1900 = DaysTo1900 * TicksPerDay;

  var ntpData = new byte[48];
  ntpData[0] = 0x1B; // LeapIndicator = 0 (no warning), VersionNum = 3 (IPv4 only), Mode = 3 (Client Mode)

  var addresses = Dns.GetHostEntry(NtpServer).AddressList;
  var ipEndPoint = new IPEndPoint(addresses[0], 123);
  long pingDuration = Stopwatch.GetTimestamp(); // temp access (JIT-Compiler need some time at first call)
  using (var socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp))
  {
    socket.Connect(ipEndPoint);
    socket.ReceiveTimeout = 5000;
    socket.Send(ntpData);
    pingDuration = Stopwatch.GetTimestamp(); // after Send-Method to reduce WinSocket API-Call time

    socket.Receive(ntpData);
    pingDuration = Stopwatch.GetTimestamp() - pingDuration;
  }

  long pingTicks = pingDuration * TicksPerSecond / Stopwatch.Frequency;

  // optional: display response-time
  // Console.WriteLine("{0:N2} ms", new TimeSpan(pingTicks).TotalMilliseconds);

  long intPart = (long)ntpData[40] << 24 | (long)ntpData[41] << 16 | (long)ntpData[42] << 8 | ntpData[43];
  long fractPart = (long)ntpData[44] << 24 | (long)ntpData[45] << 16 | (long)ntpData[46] << 8 | ntpData[47];
  long netTicks = intPart * TicksPerSecond + (fractPart * TicksPerSecond >> 32);

  var networkDateTime = new DateTime(TicksTo1900 + netTicks + pingTicks / 2);

  return networkDateTime.ToLocalTime(); // without ToLocalTime() = faster
}

http://www.codeproject.com/Articles/237501/Windows-Phone-NTP-Client wird für Windows Phone gut funktionieren.

Hinzufügen des entsprechenden Codes

/// <summary>
/// Class for acquiring time via Ntp. Useful for applications in which correct world time must be used and the 
/// clock on the device isn't "trusted."
/// </summary>
public class NtpClient
{
    /// <summary>
    /// Contains the time returned from the Ntp request
    /// </summary>
    public class TimeReceivedEventArgs : EventArgs
    {
        public DateTime CurrentTime { get; internal set; }
    }

    /// <summary>
    /// Subscribe to this event to receive the time acquired by the NTP requests
    /// </summary>
    public event EventHandler<TimeReceivedEventArgs> TimeReceived;

    protected void OnTimeReceived(DateTime time)
    {
        if (TimeReceived != null)
        {
            TimeReceived(this, new TimeReceivedEventArgs() { CurrentTime = time });
        }
    }


    /// <summary>
    /// Not reallu used. I put this here so that I had a list of other NTP servers that could be used. I'll integrate this
    /// information later and will provide method to allow some one to choose an NTP server.
    /// </summary>
    public string[] NtpServerList = new string[]
    {
        "pool.ntp.org ",
        "asia.pool.ntp.org",
        "europe.pool.ntp.org",
        "north-america.pool.ntp.org",
        "oceania.pool.ntp.org",
        "south-america.pool.ntp.org",
        "time-a.nist.gov"
    };

    string _serverName;
    private Socket _socket;

    /// <summary>
    /// Constructor allowing an NTP server to be specified
    /// </summary>
    /// <param name="serverName">the name of the NTP server to be used</param>
    public NtpClient(string serverName)
    {
        _serverName = serverName;
    }


    /// <summary>
    /// 
    /// </summary>
    public NtpClient()
        : this("time-a.nist.gov")
    { }

    /// <summary>
    /// Begins the network communication required to retrieve the time from the NTP server
    /// </summary>
    public void RequestTime()
    {
        byte[] buffer = new byte[48];
        buffer[0] = 0x1B;
        for (var i = 1; i < buffer.Length; ++i)
            buffer[i] = 0;
        DnsEndPoint _endPoint = new DnsEndPoint(_serverName, 123);

        _socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
        SocketAsyncEventArgs sArgsConnect = new SocketAsyncEventArgs() { RemoteEndPoint = _endPoint };
        sArgsConnect.Completed += (o, e) =>
        {
            if (e.SocketError == SocketError.Success)
            {
                SocketAsyncEventArgs sArgs = new SocketAsyncEventArgs() { RemoteEndPoint = _endPoint };
                sArgs.Completed +=
                    new EventHandler<SocketAsyncEventArgs>(sArgs_Completed);
                sArgs.SetBuffer(buffer, 0, buffer.Length);
                sArgs.UserToken = buffer;
                _socket.SendAsync(sArgs);
            }
        };
        _socket.ConnectAsync(sArgsConnect);

    }

    void sArgs_Completed(object sender, SocketAsyncEventArgs e)
    {
        if (e.SocketError == SocketError.Success)
        {
            byte[] buffer = (byte[])e.Buffer;
            SocketAsyncEventArgs sArgs = new SocketAsyncEventArgs();
            sArgs.RemoteEndPoint = e.RemoteEndPoint;

            sArgs.SetBuffer(buffer, 0, buffer.Length);
            sArgs.Completed += (o, a) =>
            {
                if (a.SocketError == SocketError.Success)
                {
                    byte[] timeData = a.Buffer;

                    ulong hTime = 0;
                    ulong lTime = 0;

                    for (var i = 40; i <= 43; ++i)
                        hTime = hTime << 8 | buffer[i];
                    for (var i = 44; i <= 47; ++i)
                        lTime = lTime << 8 | buffer[i];
                    ulong milliseconds = (hTime * 1000 + (lTime * 1000) / 0x100000000L);

                    TimeSpan timeSpan =
                        TimeSpan.FromTicks((long)milliseconds * TimeSpan.TicksPerMillisecond);
                    var currentTime = new DateTime(1900, 1, 1) + timeSpan;
                    OnTimeReceived(currentTime);

                }
            };
            _socket.ReceiveAsync(sArgs);
        }
    }
}

Verwendung :

public partial class MainPage : PhoneApplicationPage
{
    private NtpClient _ntpClient;
    public MainPage()
    {
        InitializeComponent();
        _ntpClient = new NtpClient();
        _ntpClient.TimeReceived += new EventHandler<NtpClient.TimeReceivedEventArgs>(_ntpClient_TimeReceived);
    }

    void _ntpClient_TimeReceived(object sender, NtpClient.TimeReceivedEventArgs e)
    {
        this.Dispatcher.BeginInvoke(() =>
                                        {
                                            txtCurrentTime.Text = e.CurrentTime.ToLongTimeString();
                                            txtSystemTime.Text = DateTime.Now.ToUniversalTime().ToLongTimeString();
                                        });
    }

    private void UpdateTimeButton_Click(object sender, RoutedEventArgs e)
    {
        _ntpClient.RequestTime();
    }
}