TCP communication between Windows 10 and Windows IOT core

Question

I couldn't figure out whats stopping the communication between Windows 10 IOT Core and Windows 10 machine. My setup is as follows , 1) NXP imx6 installed with Windows 10 IOT 2) My dev sandbox installed with windows 10 3) Both machines are in same subnet

Installed a TCP port forwarding UWP app on Windows 10 IOT core (Copied code as it is and customized to make it UWP app, reference from Git hub provided below).

https://gist.github.com/bongbongco/588abf3928cbd297443dd9da8171eb9a

The app running successfully on Windows 10 IOT , it fails to accept the client connection request from my Windows 10 machine. The app keeps waiting for the client connection at following line of code

source = _mainSocket.Accept();

from my client machine(Windows 10 dev machine) when i try connecting to Windows 10 IOT core i receive connection timeout exception.

I am trying to telnet 8081 to iMX6 board having windows 10 IOT Core installed, but i am getting the error "Could not open connection to the host, on port 8081: connect failed"

When i ping to the iMX6 machine i get a reply, my question is that , is IOT core has specific ports open?

or some firewall settings we need to enable? If so how to enable.

I have installed the following image from NXP "W1860_1_0_1_EVK_iMX6ULL_512MB_TestOEMInput-xml-Release.ffu"

Let me know your thoughts what could be an issue.
Does any one has working port forwarding app developed in UWP?

Some observations from my side 1) I could ping to my Windows 10 IOT core 2) I can install, manage apps on Windows 10 IOT core 3) While debugging the app remotely via visual studio, all dependent framework libraries are installed

Couple of questions pondering me 1) Is it possible to communicate between Windows 10 and Windows 10 IOT , using TCP protocol 2) am i missing any libraries on Windows 10 IOT

My Server Program below

/// <summary>
/// TCP server is used to connect, disconnect and manage TCP sessions
/// </summary>
/// <remarks>Thread-safe</remarks>
public class TcpServer : IDisposable
{
    /// <summary>
    /// Initialize TCP server with a given IP address and port number
    /// </summary>
    /// <param name="address">IP address</param>
    /// <param name="port">Port number</param>
    public TcpServer(IPAddress address, int port) : this(new IPEndPoint(address, port)) {}
    /// <summary>
    /// Initialize TCP server with a given IP address and port number
    /// </summary>
    /// <param name="address">IP address</param>
    /// <param name="port">Port number</param>
    public TcpServer(string address, int port) : this(new IPEndPoint(IPAddress.Parse(address), port)) {}
    /// <summary>
    /// Initialize TCP server with a given IP endpoint
    /// </summary>
    /// <param name="endpoint">IP endpoint</param>
    public TcpServer(IPEndPoint endpoint)
    {
        Id = Guid.NewGuid();
        Endpoint = endpoint;
    }

    /// <summary>
    /// Server Id
    /// </summary>
    public Guid Id { get; }

    /// <summary>
    /// IP endpoint
    /// </summary>
    public IPEndPoint Endpoint { get; private set; }

    /// <summary>
    /// Number of sessions connected to the server
    /// </summary>
    public long ConnectedSessions { get { return Sessions.Count; } }
    /// <summary>
    /// Number of bytes pending sent by the server
    /// </summary>
    public long BytesPending { get { return _bytesPending; } }
    /// <summary>
    /// Number of bytes sent by the server
    /// </summary>
    public long BytesSent { get { return _bytesSent; } }
    /// <summary>
    /// Number of bytes received by the server
    /// </summary>
    public long BytesReceived { get { return _bytesReceived; } }

    /// <summary>
    /// Option: acceptor backlog size
    /// </summary>
    /// <remarks>
    /// This option will set the listening socket's backlog size
    /// </remarks>
    public int OptionAcceptorBacklog { get; set; } = 1024;
    /// <summary>
    /// Option: keep alive
    /// </summary>
    /// <remarks>
    /// This option will setup SO_KEEPALIVE if the OS support this feature
    /// </remarks>
    public bool OptionKeepAlive { get; set; }
    /// <summary>
    /// Option: no delay
    /// </summary>
    /// <remarks>
    /// This option will enable/disable Nagle's algorithm for TCP protocol
    /// </remarks>
    public bool OptionNoDelay { get; set; }
    /// <summary>
    /// Option: reuse address
    /// </summary>
    /// <remarks>
    /// This option will enable/disable SO_REUSEADDR if the OS support this feature
    /// </remarks>
    public bool OptionReuseAddress { get; set; }
    /// <summary>
    /// Option: enables a socket to be bound for exclusive access
    /// </summary>
    /// <remarks>
    /// This option will enable/disable SO_EXCLUSIVEADDRUSE if the OS support this feature
    /// </remarks>
    public bool OptionExclusiveAddressUse { get; set; }

    #region Start/Stop server

    // Server acceptor
    private Socket _acceptorSocket;
    private SocketAsyncEventArgs _acceptorEventArg;

    // Server statistic
    internal long _bytesPending;
    internal long _bytesSent;
    internal long _bytesReceived;

    /// <summary>
    /// Is the server started?
    /// </summary>
    public bool IsStarted { get; private set; }
    /// <summary>
    /// Is the server accepting new clients?
    /// </summary>
    public bool IsAccepting { get; private set; }

    /// <summary>
    /// Start the server
    /// </summary>
    /// <returns>'true' if the server was successfully started, 'false' if the server failed to start</returns>
    public virtual bool Start()
    {
        Debug.Assert(!IsStarted, "TCP server is already started!");
        if (IsStarted)
            return false;

        // Setup acceptor event arg
        _acceptorEventArg = new SocketAsyncEventArgs();
        _acceptorEventArg.Completed += OnAsyncCompleted;

        // Create a new acceptor socket
        _acceptorSocket = new Socket(Endpoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp);

        // Apply the option: reuse address
        _acceptorSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, OptionReuseAddress);
        // Apply the option: exclusive address use
        _acceptorSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ExclusiveAddressUse, OptionExclusiveAddressUse);

        // Bind the acceptor socket to the IP endpoint
        _acceptorSocket.Bind(Endpoint);
        // Refresh the endpoint property based on the actual endpoint created
        Endpoint = (IPEndPoint)_acceptorSocket.LocalEndPoint;
        // Start listen to the acceptor socket with the given accepting backlog size
        _acceptorSocket.Listen(OptionAcceptorBacklog);

        // Reset statistic
        _bytesPending = 0;
        _bytesSent = 0;
        _bytesReceived = 0;

        // Update the started flag
        IsStarted = true;

        // Call the server started handler
        OnStarted();

        // Perform the first server accept
        IsAccepting = true;
        StartAccept(_acceptorEventArg);

        return true;
    }

    /// <summary>
    /// Stop the server
    /// </summary>
    /// <returns>'true' if the server was successfully stopped, 'false' if the server is already stopped</returns>
    public virtual bool Stop()
    {
        Debug.Assert(IsStarted, "TCP server is not started!");
        if (!IsStarted)
            return false;

        // Stop accepting new clients
        IsAccepting = false;

        // Reset acceptor event arg
        _acceptorEventArg.Completed -= OnAsyncCompleted;

        // Close the acceptor socket
        _acceptorSocket.Close();

        // Dispose the acceptor socket
        _acceptorSocket.Dispose();

        // Disconnect all sessions
        DisconnectAll();

        // Update the started flag
        IsStarted = false;

        // Call the server stopped handler
        OnStopped();

        return true;
    }

    /// <summary>
    /// Restart the server
    /// </summary>
    /// <returns>'true' if the server was successfully restarted, 'false' if the server failed to restart</returns>
    public virtual bool Restart()
    {
        if (!Stop())
            return false;

        while (IsStarted)
            Thread.Yield();

        return Start();
    }

    #endregion

    #region Accepting clients

    /// <summary>
    /// Start accept a new client connection
    /// </summary>
    private void StartAccept(SocketAsyncEventArgs e)
    {
        // Socket must be cleared since the context object is being reused
        e.AcceptSocket = null;

        // Async accept a new client connection
        if (!_acceptorSocket.AcceptAsync(e))
            ProcessAccept(e);
    }

    /// <summary>
    /// Process accepted client connection
    /// </summary>
    private void ProcessAccept(SocketAsyncEventArgs e)
    {
        if (e.SocketError == SocketError.Success)
        {
            // Create a new session to register
            var session = CreateSession();

            // Register the session
            RegisterSession(session);

            // Connect new session
            session.Connect(e.AcceptSocket);
        }
        else
            SendError(e.SocketError);

        // Accept the next client connection
        if (IsAccepting)
            StartAccept(e);
    }

    /// <summary>
    /// This method is the callback method associated with Socket.AcceptAsync()
    /// operations and is invoked when an accept operation is complete
    /// </summary>
    private void OnAsyncCompleted(object sender, SocketAsyncEventArgs e)
    {
        ProcessAccept(e);
    }

    #endregion

    #region Session factory

    /// <summary>
    /// Create TCP session factory method
    /// </summary>
    /// <returns>TCP session</returns>
    protected virtual TcpSession CreateSession() { return new TcpSession(this); }

    #endregion

    #region Session management

    // Server sessions
    protected readonly ConcurrentDictionary<Guid, TcpSession> Sessions = new ConcurrentDictionary<Guid, TcpSession>();

    /// <summary>
    /// Disconnect all connected sessions
    /// </summary>
    /// <returns>'true' if all sessions were successfully disconnected, 'false' if the server is not started</returns>
    public virtual bool DisconnectAll()
    {
        if (!IsStarted)
            return false;

        // Disconnect all sessions
        foreach (var session in Sessions.Values)
            session.Disconnect();

        return true;
    }

    /// <summary>
    /// Find a session with a given Id
    /// </summary>
    /// <param name="id">Session Id</param>
    /// <returns>Session with a given Id or null if the session it not connected</returns>
    public TcpSession FindSession(Guid id)
    {
        // Try to find the required session
        return Sessions.TryGetValue(id, out TcpSession result) ? result : null;
    }

    /// <summary>
    /// Register a new session
    /// </summary>
    /// <param name="session">Session to register</param>
    internal void RegisterSession(TcpSession session)
    {
        // Register a new session
        Sessions.TryAdd(session.Id, session);
    }

    /// <summary>
    /// Unregister session by Id
    /// </summary>
    /// <param name="id">Session Id</param>
    internal void UnregisterSession(Guid id)
    {
        // Unregister session by Id
        Sessions.TryRemove(id, out TcpSession temp);
    }

    #endregion

    #region Multicasting

    /// <summary>
    /// Multicast data to all connected sessions
    /// </summary>
    /// <param name="buffer">Buffer to multicast</param>
    /// <returns>'true' if the data was successfully multicasted, 'false' if the data was not multicasted</returns>
    public virtual bool Multicast(byte[] buffer) { return Multicast(buffer, 0, buffer.Length); }

    /// <summary>
    /// Multicast data to all connected clients
    /// </summary>
    /// <param name="buffer">Buffer to multicast</param>
    /// <param name="offset">Buffer offset</param>
    /// <param name="size">Buffer size</param>
    /// <returns>'true' if the data was successfully multicasted, 'false' if the data was not multicasted</returns>
    public virtual bool Multicast(byte[] buffer, long offset, long size)
    {
        if (!IsStarted)
            return false;

        if (size == 0)
            return true;

        // Multicast data to all sessions
        foreach (var session in Sessions.Values)
            session.SendAsync(buffer, offset, size);

        return true;
    }

    /// <summary>
    /// Multicast text to all connected clients
    /// </summary>
    /// <param name="text">Text string to multicast</param>
    /// <returns>'true' if the text was successfully multicasted, 'false' if the text was not multicasted</returns>
    public virtual bool Multicast(string text) { return Multicast(Encoding.UTF8.GetBytes(text)); }

    #endregion

    #region Server handlers

    /// <summary>
    /// Handle server started notification
    /// </summary>
    protected virtual void OnStarted() {}
    /// <summary>
    /// Handle server stopped notification
    /// </summary>
    protected virtual void OnStopped() {}

    /// <summary>
    /// Handle session connected notification
    /// </summary>
    /// <param name="session">Connected session</param>
    protected virtual void OnConnected(TcpSession session) {}
    /// <summary>
    /// Handle session disconnected notification
    /// </summary>
    /// <param name="session">Disconnected session</param>
    protected virtual void OnDisconnected(TcpSession session) {}

    /// <summary>
    /// Handle error notification
    /// </summary>
    /// <param name="error">Socket error code</param>
    protected virtual void OnError(SocketError error) {}

    internal void OnConnectedInternal(TcpSession session) { OnConnected(session); }
    internal void OnDisconnectedInternal(TcpSession session) { OnDisconnected(session); }

    #endregion

    #region Error handling

    /// <summary>
    /// Send error notification
    /// </summary>
    /// <param name="error">Socket error code</param>
    private void SendError(SocketError error)
    {
        // Skip disconnect errors
        if ((error == SocketError.ConnectionAborted) ||
            (error == SocketError.ConnectionRefused) ||
            (error == SocketError.ConnectionReset) ||
            (error == SocketError.OperationAborted) ||
            (error == SocketError.Shutdown))
            return;

        OnError(error);
    }

    #endregion

    #region IDisposable implementation

    // Disposed flag.
    private bool _disposed;

    // Implement IDisposable.
    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }

    protected virtual void Dispose(bool disposingManagedResources)
    {
        // The idea here is that Dispose(Boolean) knows whether it is
        // being called to do explicit cleanup (the Boolean is true)
        // versus being called due to a garbage collection (the Boolean
        // is false). This distinction is useful because, when being
        // disposed explicitly, the Dispose(Boolean) method can safely
        // execute code using reference type fields that refer to other
        // objects knowing for sure that these other objects have not been
        // finalized or disposed of yet. When the Boolean is false,
        // the Dispose(Boolean) method should not execute code that
        // refer to reference type fields because those objects may
        // have already been finalized."

        if (!_disposed)
        {
            if (disposingManagedResources)
            {
                // Dispose managed resources here...
                Stop();
            }

            // Dispose unmanaged resources here...

            // Set large fields to null here...

            // Mark as disposed.
            _disposed = true;
        }
    }

    // Use C# destructor syntax for finalization code.
    ~TcpServer()
    {
        // Simply call Dispose(false).
        Dispose(false);
    }

    #endregion
}

My Main Program:

public class Program
{

    static void Main(string[] args)
    {
        // TCP server port
        int port = 1111;
        if (args.Length > 0)
            port = int.Parse(args[0]);

        Console.WriteLine($"TCP server port: {port}");

        Console.WriteLine();

        // Create a new TCP chat server
        var server = new TcpServer(IPAddress.Any, port);

        // Start the server
        Console.Write("Server starting...");
        server.Start();
        Console.WriteLine("Done!");

        Console.WriteLine("Press Enter to stop the server or '!' to restart the server...");

        // Perform text input
        for (; ; )
        {
            string line = Console.ReadLine();
            if (string.IsNullOrEmpty(line))
                break;

            // Restart the server
            if (line == "!")
            {
                Console.Write("Server restarting...");
                server.Restart();
                Console.WriteLine("Done!");
                continue;
            }

            // Multicast admin message to all sessions
            line = "(admin) " + line;
            server.Multicast(line);
        }

        // Stop the server
        Console.Write("Server stopping...");
        server.Stop();
        Console.WriteLine("Done!");
    }
}

Thanks

Answer 1

Yes, it is possible to communicate between Windows 10 and Windows 10 IoT Core using TCP protocol. You need to follow these two steps:

1. Specify the port in your firewall setting on your server device via this command.

   netsh advfirewall firewall add rule name="Web Access" dir=in protocol=TCP localport=8081 action=Allow

2. Add the privateNetworkClientServer capability in your UWP app. You may refer to this document(https://learn.microsoft.com/en-us/windows/uwp/networking/sockets#build-a-basic-tcp-socket-client-and-server).