private static DateTime ComputeUtcResult(SNTPMessage sntpMessage, DateTime destinationTimestamp)
{
var originateSeconds = GetTotalSeconds(sntpMessage.OriginTimestamp.ByteArray);
var receiveSeconds = GetTotalSeconds(sntpMessage.ReceiveTimestamp.ByteArray);
var transmitSeconds = GetTotalSeconds(sntpMessage.TransmitTimestamp.ByteArray);
var destinationSeconds = (destinationTimestamp - SNTPMessage.Era0).TotalSeconds;
var offset = 0.5 * (receiveSeconds - originateSeconds + transmitSeconds - destinationSeconds);
return(destinationTimestamp.AddSeconds(offset));
}
public static DateTime UtcRequest(Socket client, EndPoint serverAddress)
{
client.Connect(serverAddress);
var firstMessage = new SNTPMessage(ModeType.ClientMode);
client.Send(firstMessage.ResultMessage);
var serverResponse = new byte[SNTPMessage.PackageBytesCount];
client.Receive(serverResponse);
var destinationTimestamp = DateTime.UtcNow;
var secondMessage = new SNTPMessage(serverResponse);
secondMessage.OriginTimestamp.ByteArray = firstMessage.OriginTimestamp.ByteArray;
return(ComputeUtcResult(secondMessage, destinationTimestamp));
}
public static void UtcReplay(Socket server, EndPoint remoteAddress, int secondsOffset, int receiveTimeout)
{
server.ReceiveTimeout = receiveTimeout;
server.SendTimeout = SendTimeout;
var clientRequest = new byte[SNTPMessage.PackageBytesCount];
server.ReceiveFrom(clientRequest, ref remoteAddress);
var destinationTimestamp = DateTime.UtcNow;
var serverReplay = new SNTPMessage(clientRequest)
{
Mode = ModeType.ServerMode
};
serverReplay.ReceiveTimestamp.ByteArray = SNTPMessage.ConvertDateTimeToBytes(destinationTimestamp);
serverReplay.TransmitTimestamp.ByteArray = SNTPMessage.ConvertDateTimeToBytes(
DateTime.UtcNow.AddSeconds(secondsOffset));
server.SendTo(serverReplay.ResultMessage, remoteAddress);
}
