private async Task initializeClient(int timeout, CancellationToken cancellationToken)
{
_client = new TcpClient(RemoteHost, Port);
await _client.ConnectAsync(timeout, cancellationToken);
try
{
// Send Auto-Assign Client Node Request
SendMessageResult sendResult = await sendMessageAsync(enTCPCommandCode.NodeAddressToPLC, new byte[4], timeout, cancellationToken);
// Receive Client Node ID
ReceiveMessageResult receiveResult = await receiveMessageAsync(enTCPCommandCode.NodeAddressFromPLC, timeout, cancellationToken);
if (receiveResult.Message.Length < 8)
{
throw new OmronException("Failed to Negotiate a TCP Connection with Omron PLC '" + RemoteHost + ":" + Port + "' - TCP Negotiation Message Length was too Short");
}
byte[] tcpNegotiationMessage = receiveResult.Message.Slice(0, 8).ToArray();
if (tcpNegotiationMessage[3] == 0 || tcpNegotiationMessage[3] == 255)
{
throw new OmronException("Failed to Negotiate a TCP Connection with Omron PLC '" + RemoteHost + ":" + Port + "' - TCP Negotiation Message contained an Invalid Local Node ID");
}
_localNodeId = tcpNegotiationMessage[3];
if (tcpNegotiationMessage[7] == 0 || tcpNegotiationMessage[7] == 255)
{
throw new OmronException("Failed to Negotiate a TCP Connection with Omron PLC '" + RemoteHost + ":" + Port + "' - TCP Negotiation Message contained an Invalid Remote Node ID");
}
_remoteNodeId = tcpNegotiationMessage[7];
}
catch (OmronException e)
{
throw new OmronException("Failed to Negotiate a TCP Connection with Omron PLC '" + RemoteHost + ":" + Port + "'", e);
}
}
internal async Task <ProcessRequestResult> ProcessRequestAsync(FINSRequest request, int timeout, int retries, CancellationToken cancellationToken)
{
int attempts = 0;
Memory <byte> responseMessage = new Memory <byte>();
int bytesSent = 0;
int packetsSent = 0;
int bytesReceived = 0;
int packetsReceived = 0;
DateTime startTimestamp = DateTime.UtcNow;
while (attempts <= retries)
{
try
{
if (!_semaphore.Wait(0))
{
await _semaphore.WaitAsync(cancellationToken);
}
if (attempts > 0)
{
await DestroyAndInitializeClient(timeout, cancellationToken);
}
// Build the Request into a Message we can Send
ReadOnlyMemory <byte> requestMessage = request.BuildMessage(getNextRequestId());
// Send the Message
SendMessageResult sendResult = await SendMessageAsync(requestMessage, timeout, cancellationToken);
bytesSent += sendResult.Bytes;
packetsSent += sendResult.Packets;
// Receive a Response
ReceiveMessageResult receiveResult = await ReceiveMessageAsync(timeout, cancellationToken);
bytesReceived += receiveResult.Bytes;
packetsReceived += receiveResult.Packets;
responseMessage = receiveResult.Message;
break;
}
catch (Exception)
{
if (attempts >= retries)
{
throw;
}
}
finally
{
_semaphore.Release();
}
// Increment the Attempts
attempts++;
}
try
{
return(new ProcessRequestResult
{
BytesSent = bytesSent,
PacketsSent = packetsSent,
BytesReceived = bytesReceived,
PacketsReceived = packetsReceived,
Duration = DateTime.UtcNow.Subtract(startTimestamp).TotalMilliseconds,
Response = FINSResponse.CreateNew(responseMessage, request),
});
}
catch (FINSException e)
{
if (e.Message.Contains("Service ID") && responseMessage.Length >= 9 && responseMessage.Span[9] != request.ServiceID)
{
try
{
if (!_semaphore.Wait(0))
{
await _semaphore.WaitAsync(cancellationToken);
}
await PurgeReceiveBuffer(timeout, cancellationToken);
}
catch
{
}
finally
{
_semaphore.Release();
}
}
throw new OmronException("Received a FINS Error Response from Omron PLC '" + _remoteHost + ":" + _port + "'", e);
}
}
protected override async Task <ReceiveMessageResult> ReceiveMessageAsync(int timeout, CancellationToken cancellationToken)
{
ReceiveMessageResult result = new ReceiveMessageResult
{
Bytes = 0,
Packets = 0,
Message = new Memory <byte>(),
};
try
{
List <byte> receivedData = new List <byte>();
DateTime startTimestamp = DateTime.UtcNow;
while (DateTime.UtcNow.Subtract(startTimestamp).TotalMilliseconds < timeout && receivedData.Count < FINSResponse.HEADER_LENGTH + FINSResponse.COMMAND_LENGTH + FINSResponse.RESPONSE_CODE_LENGTH)
{
Memory <byte> buffer = new byte[4096];
TimeSpan receiveTimeout = TimeSpan.FromMilliseconds(timeout).Subtract(DateTime.UtcNow.Subtract(startTimestamp));
if (receiveTimeout.TotalMilliseconds >= 50)
{
int receivedBytes = await _client.ReceiveAsync(buffer, receiveTimeout, cancellationToken);
if (receivedBytes > 0)
{
receivedData.AddRange(buffer.Slice(0, receivedBytes).ToArray());
result.Bytes += receivedBytes;
result.Packets += 1;
}
}
}
if (receivedData.Count == 0)
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - No Data was Received");
}
if (receivedData.Count < FINSResponse.HEADER_LENGTH + FINSResponse.COMMAND_LENGTH + FINSResponse.RESPONSE_CODE_LENGTH)
{
throw new OmronException("Failed to Receive FINS Message within the Timeout Period from Omron PLC '" + RemoteHost + ":" + Port + "'");
}
if (receivedData[0] != 0xC0 && receivedData[0] != 0xC1)
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - The FINS Header was Invalid");
}
result.Message = receivedData.ToArray();
}
catch (ObjectDisposedException)
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - The underlying Socket Connection has been Closed");
}
catch (TimeoutException)
{
throw new OmronException("Failed to Receive FINS Message within the Timeout Period from Omron PLC '" + RemoteHost + ":" + Port + "'");
}
catch (System.Net.Sockets.SocketException e)
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "'", e);
}
return(result);
}
private async Task <ReceiveMessageResult> receiveMessageAsync(enTCPCommandCode command, int timeout, CancellationToken cancellationToken)
{
ReceiveMessageResult result = new ReceiveMessageResult
{
Bytes = 0,
Packets = 0,
Message = new Memory <byte>(),
};
try
{
List <byte> receivedData = new List <byte>();
DateTime startTimestamp = DateTime.UtcNow;
while (DateTime.UtcNow.Subtract(startTimestamp).TotalMilliseconds < timeout && receivedData.Count < TCP_HEADER_LENGTH)
{
Memory <byte> buffer = new byte[4096];
TimeSpan receiveTimeout = TimeSpan.FromMilliseconds(timeout).Subtract(DateTime.UtcNow.Subtract(startTimestamp));
if (receiveTimeout.TotalMilliseconds >= 50)
{
int receivedBytes = await _client.ReceiveAsync(buffer, receiveTimeout, cancellationToken);
if (receivedBytes > 0)
{
receivedData.AddRange(buffer.Slice(0, receivedBytes).ToArray());
result.Bytes += receivedBytes;
result.Packets += 1;
}
}
}
if (receivedData.Count == 0)
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - No Data was Received");
}
if (receivedData.Count < TCP_HEADER_LENGTH)
{
throw new OmronException("Failed to Receive FINS Message within the Timeout Period from Omron PLC '" + RemoteHost + ":" + Port + "'");
}
if (receivedData[0] != 'F' || receivedData[1] != 'I' || receivedData[2] != 'N' || receivedData[3] != 'S')
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - The TCP Header was Invalid");
}
byte[] tcpHeader = receivedData.GetRange(0, TCP_HEADER_LENGTH).ToArray();
int tcpMessageDataLength = (int)BitConverter.ToUInt32(new byte[] { receivedData[7], receivedData[6], receivedData[5], receivedData[4] }) - 8;
if (tcpMessageDataLength <= 0 || tcpMessageDataLength > short.MaxValue)
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - The TCP Message Length was Invalid");
}
if (receivedData[11] == 3 || receivedData[15] != 0)
{
switch (receivedData[15])
{
case 1:
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - Omron TCP Error: The FINS Identifier (ASCII Code) was Invalid.");
case 2:
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - Omron TCP Error: The Data Length is too Long.");
case 3:
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - Omron TCP Error: The Command is not Supported.");
case 20:
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - Omron TCP Error: All Connections are in Use.");
case 21:
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - Omron TCP Error: The Specified Node is already Connected.");
case 22:
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - Omron TCP Error: Attempt to Access a Protected Node from an Unspecified IP Address.");
case 23:
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - Omron TCP Error: The Client FINS Node Address is out of Range.");
case 24:
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - Omron TCP Error: The same FINS Node Address is being used by the Client and Server.");
case 25:
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - Omron TCP Error: All the Node Addresses Available for Allocation have been Used.");
default:
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - Omron TCP Error: Unknown Code '" + receivedData[15] + "'");
}
}
if (receivedData[8] != 0 || receivedData[9] != 0 || receivedData[10] != 0 || receivedData[11] != (byte)command)
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - The TCP Command Received '" + receivedData[11] + "' did not match Expected Command '" + (byte)command + "'");
}
if (command == enTCPCommandCode.FINSFrame && tcpMessageDataLength < FINSResponse.HEADER_LENGTH + FINSResponse.COMMAND_LENGTH + FINSResponse.RESPONSE_CODE_LENGTH)
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - The TCP Message Length was too short for a FINS Frame");
}
receivedData.RemoveRange(0, TCP_HEADER_LENGTH);
if (receivedData.Count < tcpMessageDataLength)
{
startTimestamp = DateTime.UtcNow;
while (DateTime.UtcNow.Subtract(startTimestamp).TotalMilliseconds < timeout && receivedData.Count < tcpMessageDataLength)
{
Memory <byte> buffer = new byte[4096];
TimeSpan receiveTimeout = TimeSpan.FromMilliseconds(timeout).Subtract(DateTime.UtcNow.Subtract(startTimestamp));
if (receiveTimeout.TotalMilliseconds >= 50)
{
int receivedBytes = await _client.ReceiveAsync(buffer, receiveTimeout, cancellationToken);
if (receivedBytes > 0)
{
receivedData.AddRange(buffer.Slice(0, receivedBytes).ToArray());
}
result.Bytes += receivedBytes;
result.Packets += 1;
}
}
}
if (receivedData.Count == 0)
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - No Data was Received after TCP Header");
}
if (receivedData.Count < tcpMessageDataLength)
{
throw new OmronException("Failed to Receive FINS Message within the Timeout Period from Omron PLC '" + RemoteHost + ":" + Port + "'");
}
if (command == enTCPCommandCode.FINSFrame && receivedData[0] != 0xC0 && receivedData[0] != 0xC1)
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - The FINS Header was Invalid");
}
result.Message = receivedData.ToArray();
}
catch (ObjectDisposedException)
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "' - The underlying Socket Connection was Closed");
}
catch (TimeoutException)
{
throw new OmronException("Failed to Receive FINS Message within the Timeout Period from Omron PLC '" + RemoteHost + ":" + Port + "'");
}
catch (System.Net.Sockets.SocketException e)
{
throw new OmronException("Failed to Receive FINS Message from Omron PLC '" + RemoteHost + ":" + Port + "'", e);
}
return(result);
}