private async Task <Instant> GetNetworkTimeAsync()
{
// http://stackoverflow.com/a/12150289
// 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] = 0x23; // 0010 0011 : LI = 0 (no warning), VN = 4 (IPv4 or IPv6), Mode = 3 (Client Mode)
var ipEndPoint = await ResolveIPEndPointAsync().ConfigureAwait(false);
using (var socket = new Socket(ipEndPoint.AddressFamily, SocketType.Dgram, ProtocolType.Udp))
{
await socket.ConnectAsync(ipEndPoint).ConfigureAwait(false);
//Stops code hang if NTP is blocked
socket.ReceiveTimeout = 3000;
var buffer = new ArraySegment <byte>(ntpData);
await socket.SendAsync(buffer, SocketFlags.None).ConfigureAwait(false);
await socket.ReceiveAsync(buffer, SocketFlags.None).ConfigureAwait(false);
}
//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 = (long)(intPart * 1000 + fractPart * 1000 / 0x100000000L);
var instant = Instant.FromUtc(1900, 1, 1, 0, 0) + Duration.FromMilliseconds(milliseconds);
return(instant);
}
/// <summary>
/// Initializes a new instance of the <see cref="Instant" /> struct based
/// on a number of milliseconds since the Unix epoch of (ISO) January 1st 1970, midnight, UTC.
/// </summary>
/// <param name="milliseconds">Number of milliseconds since the Unix epoch. May be negative (for instants before the epoch).</param>
/// <returns>An <see cref="Instant"/> at exactly the given number of milliseconds since the Unix epoch.</returns>
/// <exception cref="ArgumentOutOfRangeException">The constructed instant would be out of the range representable in Noda Time.</exception>
public static Instant FromUnixTimeMilliseconds(long milliseconds)
{
Preconditions.CheckArgumentRange(nameof(milliseconds), milliseconds, MinMilliseconds, MaxMilliseconds);
return(Instant.FromTrustedDuration(Duration.FromMilliseconds(milliseconds)));
}
public ZonedDateTime PlusMilliseconds(long milliseconds) => this + Duration.FromMilliseconds(milliseconds);
/// <summary>
/// Initializes a new instance of the <see cref="Instant" /> struct based
/// on a number of milliseconds since the Unix epoch of (ISO) January 1st 1970, midnight, UTC.
/// </summary>
/// <param name="milliseconds">Number of milliseconds since the Unix epoch. May be negative (for instants before the epoch).</param>
/// <returns>An <see cref="Instant"/> at exactly the given number of milliseconds since the Unix epoch.</returns>
/// <exception cref="ArgumentOutOfRangeException">The constructed instant would be out of the range representable in Noda Time.</exception>
public static Instant FromMillisecondsSinceUnixEpoch(long milliseconds)
{
Preconditions.CheckArgumentRange(nameof(milliseconds), milliseconds, MinMilliseconds, MaxMilliseconds);
return(new Instant(Duration.FromMilliseconds(milliseconds)));
}
/// <summary> /// From milliseconds /// </summary> /// <param name="milliseconds"></param> /// <returns></returns> public static Duration AsDurationOfMilliseconds(this double milliseconds) => Duration.FromMilliseconds(milliseconds);
