ChannelManager.cs Source Code (CNG Example)

The ChannelManager.cs file provides the source code for the ChannelManager class, which is used by the Cryptography Next Generation (CNG) secure communication example. It contains the following code.

using System;                           // Required for the IDisposable interface
using System.Text;                      // Required for the Encoding class
using System.IO;                        // Required for the MemoryStream class
using System.IO.Pipes;                  // Required for the NamedPipeClientStream class


public partial class CNG_SecureCommunicationExample
{

// Synchronize session options with the Bob and Mallory applications.
    static string AppControl(string mode, string data)
        {
        if ("send" == mode)
            {
                using (ChannelManager ChMgr = new ChannelManager("server",
                                                     "BobControlChannel"))
                    ChMgr.SendMessage(Encoding.Unicode.GetBytes(data));

                if (fMallory || "exit" == data)
                using (ChannelManager ChMgr = new ChannelManager("server",
                                                     "MalloryControlChannel"))
                    ChMgr.SendMessage(Encoding.Unicode.GetBytes(data));
            }

        else
            {
            using (ChannelManager ChMgr = new ChannelManager("client", data))
                {
                byte[] byteBuffer = ChMgr.ReadMessage();
                string options = Encoding.Unicode.GetString(byteBuffer);
                if ("exit" == options) return "exit"; 
                fVerbose = options.Substring(0,1) == "y"?true:false;
                fMallory = options.Substring(1,1) == "y"?true:false;
                Version  = Int32.Parse(options.Substring(2,1));
                }
            }
        return "";
        }

// Convert the message string into a Unicode byte array.
// Create temporary ChannelManager object.
// Send the new channel name.
// This method demonstrates a bad corporate security policy
//  and allows Mallory to substitute his own new channel name.

    static void SendChannelName(string name)
        {
        byte[] AB_Channel = Encoding.Unicode.GetBytes(name);
        using(ChannelManager ChMgr = new ChannelManager("server", "PublicChannel"))
            ChMgr.SendMessage(AB_Channel);
        }

    static string ReceiveChannelName()
        {
        using (ChannelManager ChMgr = new ChannelManager("client", "PublicChannel"))
            return  Encoding.Unicode.GetString(ChMgr.ReadMessage());
        }


// Pipe server or client class 
   internal sealed class ChannelManager  : IDisposable
        {
        NamedPipeServerStream m_ServerPipe;
        NamedPipeClientStream m_ClientPipe;
        Stream m_Stream;

        string m_ChannelType;                   // "client" or "server"
        string m_ChannelName;
        byte[] byteBuffer = new byte[1000];     // Only big enough for small messages

        public ChannelManager(string ChannelType, string ChannelName)
            {
            m_ChannelType = ChannelType;
            m_ChannelName = ChannelName;

            if ("server" == ChannelType)
                {
                m_ServerPipe = new NamedPipeServerStream(ChannelName,
                        PipeDirection.InOut, 1,
                        PipeTransmissionMode.Message);
                m_Stream = m_ServerPipe;
                m_ServerPipe.WaitForConnection();                
            }
            else 
                {
                m_ClientPipe = new NamedPipeClientStream(ChannelName);
                m_Stream = m_ClientPipe;
                m_ClientPipe.Connect(); 
                m_ClientPipe.ReadMode = PipeTransmissionMode.Message;    
                }
            }

        public void Dispose()
            {
            if (m_Stream != null)
               (m_Stream as IDisposable).Dispose();
            }

        public byte[] ReadMessage()
            {
            MemoryStream ms = new MemoryStream();
            int count;

            do {
               count = m_Stream.Read(byteBuffer, 0 , byteBuffer.Length);
               if (count > 0 )
                   ms.Write(byteBuffer, 0 ,count);
               } while (count == byteBuffer.Length);
            byte[] bA = ms.ToArray();
            return bA;
            }

        public bool SendMessage(byte[] msg)
            {
            try
                {
                m_Stream.Write(msg, 0, msg.Length);
                }
            catch (IOException e)
                {
                Display("Connection has been closed.\n" + e +"\n", MyColor);
                return false;
                }
            return true;
            }
        }   // End class ChannelManager

}       // End ChannelManager.cs: public partial class CNG_SecureCommunicationExample

See Also

Tasks

How to: Build and Run the CNG Example

Concepts

Source Code Overview (CNG Example)

Cryptography Next Generation (CNG) Secure Communication Example

Other Resources

Cryptographic Services