/// <summary>
/// Read a NTP time stamp from the packet at offset
/// </summary>
/// <param name="Packet">Packet to pull timestamp from</param>
/// <param name="Offset">Offset from start of packet</param>
/// <returns>Timestamp that was read</returns>
private NtpTimeStamp ReadTimeStampSequenctial(byte[] Packet, ref uint Offset)
{
NtpTimeStamp time = new NtpTimeStamp();
time.Seconds = (uint)ReadFieldSequential(Packet, ref Offset, 4);
time.Fraction = (uint)ReadFieldSequential(Packet, ref Offset, 4);
return(time);
}
/// <summary>
/// Build a client NTP packet
/// </summary>
/// <param name="TransmitTimestamp">Timestamp to put in the packet</param>
/// <returns>Packet to be sent</returns>
private byte[] BuildNtpClientPacket(NtpTimeStamp TransmitTimestamp)
{
byte[] packet = new byte[48];
for (int i = 0; i < packet.Length; i++)
{
packet[i] = 0;
}
packet[0] = 0x23;
WriteUint(packet, 40, 4, TransmitTimestamp.Seconds);
// Transmit Timestamp
WriteUint(packet, 44, 4, TransmitTimestamp.Fraction);
return(packet);
}
/// <summary>
/// Convert a NTP timestamp to a Windows NT file time
/// </summary>
/// <param name="NtpTime">NtpTimeStamp</param>
/// <returns>Filetime</returns>
public static ulong NtpTimeStampToFileTime(NtpTimeStamp NtpTime)
{
BigInteger epochDelta = (BigInteger)((NtpEopch - FileTimeEopch).TotalSeconds);
epochDelta *= OneHundredNsInOneSecond;
BigInteger seconds = new BigInteger();
BigInteger fraction = new BigInteger();
seconds = NtpTime.Seconds;
fraction = NtpTime.Fraction;
seconds *= OneHundredNsInOneSecond;
fraction *= OneHundredNsInOneSecond;
fraction /= MaxUintPlusOne;
return((ulong)(seconds + fraction + epochDelta));
}
/// <summary>
/// Convert a Windows NT file time to a NTP timestamp
/// </summary>
/// <param name="time">Time in 100ns</param>
/// <returns>Ntp timestamp</returns>
public static NtpTimeStamp FileTimeToNtpTimeStamp(ulong Time)
{
BigInteger fileTime = Time;
BigInteger epochDelta = (BigInteger)((NtpEopch - FileTimeEopch).TotalSeconds);
NtpTimeStamp ntpTime = new NtpTimeStamp();
BigInteger seconds = new BigInteger();
BigInteger fraction = new BigInteger();
epochDelta *= OneHundredNsInOneSecond;
fileTime -= epochDelta;
seconds = fileTime / OneHundredNsInOneSecond;
fraction = fileTime % OneHundredNsInOneSecond;
fraction *= MaxUintPlusOne;
fraction /= OneHundredNsInOneSecond;
ntpTime.Seconds = (uint)seconds;
ntpTime.Fraction = (uint)fraction;
return(ntpTime);
}
