private bool IsErrorCRC(ResponseBuffer buffer, int messageLength, ModbusRequest request, int timeout)
{
var crc = Read(buffer, messageLength, 2, timeout).ToArray();
return(!CalculateCrc(buffer.Take(messageLength)).SequenceEqual(crc));
}
private void RunReceive(ModbusChannel channel)
{
lock (responseWaitHandles)
{
if (!isReceiving)
{
isReceiving = true;
try
{
var readBuffer = new ResponseBuffer(channel);
while (responseWaitHandles.Count > 0)
{
if (errorBuffer.Count >= 256)
{
RaiseUnrecognized(channel, errorBuffer.ToArray());
errorBuffer.Clear();
}
readBuffer.Read(2, 0);
ushort transactionID = (ushort)((readBuffer[0] << 8) | readBuffer[1]);
if (!responseWaitHandles.TryGetValue(transactionID, out var responseWaitHandle))
{
errorBuffer.AddRange(readBuffer);
readBuffer.Clear();
continue;
}
readBuffer.Read(2, responseWaitHandle.Timeout);
if (readBuffer[2] != 0 ||
readBuffer[3] != 0)
{
errorBuffer.AddRange(readBuffer);
readBuffer.Clear();
responseWaitHandle.Response = new ModbusCommErrorResponse(ModbusCommErrorCode.ModbusTcpSymbolError, errorBuffer, responseWaitHandle.Request);
continue;
}
var result = base.DeserializeResponse(readBuffer, responseWaitHandle.Request, responseWaitHandle.Timeout);
if (result is ModbusCommErrorResponse responseCommErrorMessage)
{
errorBuffer.AddRange(readBuffer.Take(4));
readBuffer.RemoveRange(0, 4);
responseWaitHandle.Response = result;
continue;
}
if (readBuffer.Count - 6 != (ushort)((readBuffer[4] << 8) | readBuffer[5]))
{
errorBuffer.AddRange(readBuffer.Take(4));
readBuffer.RemoveRange(0, 4);
responseWaitHandle.Response = new ModbusCommErrorResponse(ModbusCommErrorCode.ResponseTcpLengthDoNotMatch, readBuffer, responseWaitHandle.Request);
continue;
}
if (errorBuffer.Count > 0)
{
RaiseUnrecognized(channel, errorBuffer.ToArray());
errorBuffer.Clear();
}
responseWaitHandle.ResponseBuffer.AddRange(readBuffer);
readBuffer.Clear();
responseWaitHandle.Response = result;
responseWaitHandle.Set();
this.responseWaitHandles.Remove(transactionID);
}
}
catch
{
}
isReceiving = false;
}
}
}