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Wie frage ich einen NTP Server mit C # ab?

Alles, was ich brauche, ist eine Möglichkeit, einen NTP= Server mit C # abzufragen, um das Datum und die Uhrzeit des NTP= Server als string zurückzugeben. oder als DateTime.

Wie ist das in seiner einfachsten Form möglich?

98
JL.

Da die alte akzeptierte Antwort gelöscht wurde (es handelte sich um einen Link zu den Google-Code-Suchergebnissen, die nicht mehr vorhanden sind), konnte ich die folgende Frage zum späteren Nachschlagen 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;
144
Nasreddine

Dies ist eine optimierte Version der Funktion, die die Abhängigkeit von der BitConverter-Funktion aufhebt 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;
}
33
GonzaloG

Das .NET Micro Framework Toolkit gefunden im CodePlex hat ein NTPClient. Ich habe es selbst noch nie benutzt, aber es sieht gut aus.

Es gibt auch ein anderes Beispiel hier .

9
Tony Borf

Ich weiß, dass das Thema ziemlich alt ist, aber solche Tools sind immer griffbereit. Ich habe die oben genannten Ressourcen verwendet und eine Version von NtpClient erstellt, mit der statt ereignisbasiert asynchron die genaue Uhrzeit 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));
6
Momchil Marinov

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
}
5
MaxKlaxx