internal void ReceiveRequestCompleted(IAsyncResult ar)
{
IPEndPoint masterEndPoint = null;
byte[] frame;
try
{
frame = _udpClient.EndReceive(ar, ref masterEndPoint);
}
catch (ObjectDisposedException)
{
// this hapens when slave stops
return;
}
ModbusUdpSlave slave = (ModbusUdpSlave)ar.AsyncState;
_logger.DebugFormat("Read Frame completed {0} bytes", frame.Length);
_logger.InfoFormat("RX: {0}", frame.Join(", "));
IModbusMessage request = ModbusMessageFactory.CreateModbusRequest(frame.Slice(6, frame.Length - 6).ToArray());
request.TransactionId = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(frame, 0));
// perform action and build response
IModbusMessage response = slave.ApplyRequest(request);
response.TransactionId = request.TransactionId;
// write response
byte[] responseFrame = Transport.BuildMessageFrame(response);
_logger.InfoFormat("TX: {0}", responseFrame.Join(", "));
_udpClient.BeginSend(responseFrame, responseFrame.Length, masterEndPoint, WriteResponseCompleted, null);
}
private async Task HandleRequestAsync()
{
while (true)
{
#if ModBusDebug
Debug.WriteLine($"Begin reading header from Master at IP: {EndPoint}");
#endif
int readBytes = await Stream.ReadAsync(_mbapHeader, 0, 6).ConfigureAwait(false);
if (readBytes == 0)
{
#if ModBusDebug
Debug.WriteLine($"0 bytes read, Master at {EndPoint} has closed Socket connection.");
#endif
ModbusMasterTcpConnectionClosed?.Invoke(this, new TcpConnectionEventArgs(EndPoint));
return;
}
ushort frameLength = (ushort)IPAddress.HostToNetworkOrder(BitConverter.ToInt16(_mbapHeader, 4));
#if ModBusDebug
Debug.WriteLine($"Master at {EndPoint} sent header: \"{string.Join(", ", _mbapHeader)}\" with {frameLength} bytes in PDU");
#endif
_messageFrame = new byte[frameLength];
readBytes = await Stream.ReadAsync(_messageFrame, 0, frameLength).ConfigureAwait(false);
if (readBytes == 0)
{
#if ModBusDebug
Debug.WriteLine($"0 bytes read, Master at {EndPoint} has closed Socket connection.");
#endif
ModbusMasterTcpConnectionClosed?.Invoke(this, new TcpConnectionEventArgs(EndPoint));
return;
}
#if ModBusDebug
Debug.WriteLine($"Read frame from Master at {EndPoint} completed {readBytes} bytes");
#endif
byte[] frame = _mbapHeader.Concat(_messageFrame).ToArray();
#if ModBusDebug
Debug.WriteLine($"RX from Master at {EndPoint}: {string.Join(", ", frame)}");
#endif
var request = ModbusMessageFactory.CreateModbusRequest(_messageFrame);
request.TransactionId = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(frame, 0));
// perform action and build response
IModbusMessage response = _slave.ApplyRequest(request);
response.TransactionId = request.TransactionId;
// write response
byte[] responseFrame = Transport.BuildMessageFrame(response);
#if ModBusDebug
Debug.WriteLine($"TX to Master at {EndPoint}: {string.Join(", ", responseFrame)}");
#endif
await Stream.WriteAsync(responseFrame, 0, responseFrame.Length).ConfigureAwait(false);
}
}
public byte[] BuildWriteMessage(byte slaveAddress, ushort registerAddress, ushort value)
{
var request = new WriteSingleRegisterRequestResponse(
slaveAddress,
registerAddress,
value);
return(Transport.BuildMessageFrame(request));
}
public byte[] BuildReadMessage(byte slaveAddress, ushort startAddress, ushort numberOfPoints)
{
var request = new ReadHoldingInputRegistersRequest(
Modbus.ReadHoldingRegisters,
slaveAddress,
startAddress,
numberOfPoints);
return(Transport.BuildMessageFrame(request));
}
/// <summary>
/// Start slave listening for requests.
/// </summary>
public override async Task ListenAsync(CancellationToken cancellationToken = new CancellationToken())
{
Logger.Information("Start Modbus Udp Server.");
try
{
while (!cancellationToken.IsCancellationRequested)
{
UdpReceiveResult receiveResult = await _udpClient.ReceiveAsync().ConfigureAwait(false);
IPEndPoint masterEndPoint = receiveResult.RemoteEndPoint;
byte[] frame = receiveResult.Buffer;
Debug.WriteLine($"Read Frame completed {frame.Length} bytes");
Logger.LogFrameRx(frame);
IModbusMessage request =
ModbusMessageFactory.CreateModbusRequest(frame.Slice(6, frame.Length - 6).ToArray());
request.TransactionId = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(frame, 0));
// perform action and build response
IModbusMessage response = ApplyRequest(request);
if (response != null)
{
response.TransactionId = request.TransactionId;
// write response
byte[] responseFrame = Transport.BuildMessageFrame(response);
Logger.LogFrameTx(frame);
await _udpClient.SendAsync(responseFrame, responseFrame.Length, masterEndPoint)
.ConfigureAwait(false);
}
}
}
catch (SocketException se)
{
// this hapens when slave stops
if (se.SocketErrorCode != SocketError.Interrupted)
{
throw;
}
}
}
/// <summary>
/// Start slave listening for requests.
/// </summary>
public override async Task ListenAsync()
{
Debug.WriteLine("Start Modbus Udp Server.");
try
{
while (true)
{
UdpReceiveResult receiveResult = await _udpClient.ReceiveAsync().ConfigureAwait(false);
IPEndPoint masterEndPoint = receiveResult.RemoteEndPoint;
byte[] frame = receiveResult.Buffer;
#if ModBusDebug
Debug.WriteLine($"Read Frame completed {frame.Length} bytes");
Debug.WriteLine($"RX: {string.Join(", ", frame)}");
#endif
IModbusMessage request =
ModbusMessageFactory.CreateModbusRequest(frame.Slice(6, frame.Length - 6).ToArray());
request.TransactionId = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(frame, 0));
// perform action and build response
IModbusMessage response = ApplyRequest(request);
response.TransactionId = request.TransactionId;
// write response
byte[] responseFrame = Transport.BuildMessageFrame(response);
#if ModBusDebug
Debug.WriteLine($"TX: {string.Join(", ", responseFrame)}");
#endif
await _udpClient.SendAsync(responseFrame, responseFrame.Length, masterEndPoint).ConfigureAwait(false);
}
}
catch (SocketException se)
{
// this hapens when slave stops
if (se.SocketErrorCode != SocketError.Interrupted)
{
throw;
}
}
}
internal void ReadFrameCompleted(IAsyncResult ar)
{
CatchExceptionAndRemoveMasterEndPoint(() =>
{
Log.Debug($"XmlSettingsReadFile Frame completed {Stream.EndRead(ar)} bytes");
byte[] frame = _mbapHeader.Concat(_messageFrame).ToArray();
Log.Info($"RX: {frame.JoinByCommas()}");
IModbusMessage request = ModbusMessageFactory.CreateModbusRequest(frame.Slice(6, frame.Length - 6).ToArray());
request.TransactionId = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(frame, 0));
// perform action and build response
IModbusMessage response = _slave.ApplyRequest(request);
response.TransactionId = request.TransactionId;
// write response
byte[] responseFrame = Transport.BuildMessageFrame(response);
Log.Info($"TX: {responseFrame.JoinByCommas()}");
Stream.BeginWrite(responseFrame, 0, responseFrame.Length, WriteCompleted, null);
}, EndPoint);
}
/// <summary>
/// Start slave listening for requests.
/// </summary>
public override void Listen()
{
Debug.WriteLine("Start Modbus Udp Server.");
try
{
while (true)
{
IPEndPoint masterEndPoint = null;
byte[] frame;
frame = _udpClient.Receive(ref masterEndPoint);
Debug.WriteLine("Read Frame completed {frame.Length} bytes");
Debug.WriteLine("RX: {string.Join(", ", frame)}");
IModbusMessage request =
ModbusMessageFactory.CreateModbusRequest(frame.Slice(6, frame.Length - 6).ToArray());
request.TransactionId = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(frame, 0));
// perform action and build response
IModbusMessage response = ApplyRequest(request);
response.TransactionId = request.TransactionId;
// write response
byte[] responseFrame = Transport.BuildMessageFrame(response);
Debug.WriteLine("TX: {string.Join(", ", responseFrame)}");
_udpClient.Send(responseFrame, responseFrame.Length, masterEndPoint);
}
}
catch (SocketException se)
{
// this hapens when slave stops
if (se.ErrorCode != Modbus.WSACancelBlockingCall)
{
throw;
}
}
}
private void ReadFrameCompleted(IAsyncResult ar)
{
CatchExceptionAndRemoveMasterEndPoint(() =>
{
Debug.WriteLine("Read Frame completed {0} bytes", Stream.EndRead(ar));
byte[] frame = _mbapHeader.Concat(_messageFrame).ToArray();
Debug.WriteLine("RX: {0}", string.Join(", ", frame));
IModbusMessage request =
ModbusMessageFactory.CreateModbusRequest(frame.Slice(6, frame.Length - 6).ToArray());
request.TransactionId = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(frame, 0));
// perform action and build response
IModbusMessage response = _slave.ApplyRequest(request);
response.TransactionId = request.TransactionId;
// write response
byte[] responseFrame = Transport.BuildMessageFrame(response);
Debug.WriteLine("TX: {0}", string.Join(", ", responseFrame));
Stream.BeginWrite(responseFrame, 0, responseFrame.Length, WriteCompleted, null);
}, EndPoint);
}