Listen.cs

The file Listen.cs contains a single class, Listen, with the following member functions:

• Listen (constructor)–Initializes the one and only instance

• Start–Begins TCP/IP monitoring

• Stop–Stops TCP/IP monitoring

The Listen class simply listens for TCP/IP connections and spawns a TargetController thread for each new connection. This class is both simple and complete, as the remote controller requires no additional functionality from the listening thread.

  // Listen.cs // Copyright Ric Vieler, 2006 // Spawns a TargetController for each new connection using System; using System.Net; using System.Net.Sockets; using System.Threading; namespace GhostTracker {  /// <summary>  /// Summary description for Listen.  /// </summary>  public class Listen  {   MainForm mainFormPtr;   TargetController myTarget = null;   Thread myThread = null;   TcpListener myServer = null;   bool listening = false;   public Listen( MainForm parent )   {    mainFormPtr = parent;   }   /// <summary>   /// Listen for Ghost connections   /// </summary>   public void Start()   {    try    {     // Set the TcpListener on port 80.     Int32 port = 80;     // Use "0" to let the IP Stack figure out the IP Address     IPAddress localAddr = IPAddress.Parse( "0" );     myServer = new TcpListener( localAddr, port );     // Start listening for client requests.     myServer.Start();     listening = true;     // Enter the listening loop.     while ( listening )     {      // See if a connection request is pending      if ( !myServer.Pending() )      {       // Wait 50 milliseconds and then try again       Thread.Sleep( 50 );       if ( !listening )        break;       continue;      }      // Perform a blocking call to accept requests.      TcpClient client = myServer.AcceptTcpClient();      // Spawn a new TargetController for each new connection      myTarget = new TargetController( mainFormPtr, client );      myThread = new Thread( new ThreadStart( myTarget.Start ) );      // Start the TARGET thread.      myThread.Start();     }    }    catch( SocketException )    {     string message = "Could not get a port 80 socket.\n"      + "Make sure the port is not in use.\n"      + "(IIS uses port 80 on most servers)";     mainFormPtr.Alert( null, message );    }    catch( ThreadAbortException )    {     // Application is shutting down    }   }   /// <summary>   /// Clean up any resources being used.   /// </summary>   public void Stop()   {    // Stop listening for client requests.    listening = false;    Thread.Sleep( 100 );    myServer.Stop();    if( myThread != null )    {     myTarget.Stop();     // Stop the target thread.     myThread.Abort();     myThread.Join();    }   }  } }