TCPListener.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Net / System / Net / Sockets / TCPListener.cs / 1305376 / TCPListener.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Net.Sockets { 
    using System; 
    using System.Net;
    using System.Security.Permissions; 

    /// 
    /// The  class provide TCP services at a higher level of abstraction than the 
    /// class.  is used to create a host process that 
    /// listens for connections from TCP clients.
    ///  
    public class TcpListener { 

        IPEndPoint m_ServerSocketEP; 
        Socket m_ServerSocket;
        bool m_Active;
        bool m_ExclusiveAddressUse;
 

 
        ///  
        ///    
        ///       Initializes a new instance of the TcpListener class with the specified local 
        ///       end point.
        ///    
        /// 
        public TcpListener(IPEndPoint localEP) { 
            if(Logging.On)Logging.Enter(Logging.Sockets, this, "TcpListener", localEP);
            if (localEP == null) { 
                throw new ArgumentNullException("localEP"); 
            }
            m_ServerSocketEP = localEP; 
            m_ServerSocket   = new Socket(m_ServerSocketEP.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
            if(Logging.On)Logging.Exit(Logging.Sockets, this, "TcpListener", null);
        }
 
        /// 
        ///     
        ///       Initializes a new instance of the TcpListener class that listens to the 
        ///       specified IP address and port.
        ///     
        /// 
        public TcpListener(IPAddress localaddr, int port) {
            if(Logging.On)Logging.Enter(Logging.Sockets, this, "TcpListener", localaddr);
            if (localaddr == null) { 
                throw new ArgumentNullException("localaddr");
            } 
            if (!ValidationHelper.ValidateTcpPort(port)) { 
                throw new ArgumentOutOfRangeException("port");
            } 
            m_ServerSocketEP = new IPEndPoint(localaddr, port);
            m_ServerSocket   = new Socket(m_ServerSocketEP.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
            if(Logging.On)Logging.Exit(Logging.Sockets, this, "TcpListener", null);
        } 

        // implementation picks an address for client 
        ///  
        ///    
        ///       Initiailizes a new instance of the TcpListener class 
        ///       that listens on the specified
        ///       port.
        ///    
        ///  
        ///
 
        [Obsolete("This method has been deprecated. Please use TcpListener(IPAddress localaddr, int port) instead. http://go.microsoft.com/fwlink/?linkid=14202")] 
        public TcpListener(int port){
 
            if (!ValidationHelper.ValidateTcpPort(port))
                throw new ArgumentOutOfRangeException("port");

            m_ServerSocketEP = new IPEndPoint(IPAddress.Any, port); 
            m_ServerSocket = new Socket(m_ServerSocketEP.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
        } 
 
        /// 
        ///     
        ///       Used by the class to provide the underlying network socket.
        ///    
        /// 
        public Socket Server { 
            get {
                return m_ServerSocket; 
            } 
        }
 
        /// 
        ///    
        ///       Used
        ///       by the class to indicate that the listener's socket has been bound to a port 
        ///       and started listening.
        ///     
        ///  
        protected bool Active {
            get { 
                return m_Active;
            }
        }
 
        /// 
        ///     
        ///        Gets the m_Active EndPoint for the local listener socket. 
        ///    
        ///  
        public EndPoint LocalEndpoint {
            get {
                return m_Active ? m_ServerSocket.LocalEndPoint : m_ServerSocketEP;
            } 
        }
 
        public bool ExclusiveAddressUse { 
            get {
                return m_ServerSocket.ExclusiveAddressUse; 
            }
            set{
                if (m_Active) {
                    throw new InvalidOperationException(SR.GetString(SR.net_tcplistener_mustbestopped)); 
                }
                m_ServerSocket.ExclusiveAddressUse = value; 
                m_ExclusiveAddressUse = value; 
            }
        } 

        public void AllowNatTraversal(bool allowed) {
            if (m_Active) {
                throw new InvalidOperationException(SR.GetString(SR.net_tcplistener_mustbestopped)); 
            }
 
            if (allowed) { 
                m_ServerSocket.SetIPProtectionLevel(IPProtectionLevel.Unrestricted);
            } 
            else {
                m_ServerSocket.SetIPProtectionLevel(IPProtectionLevel.EdgeRestricted);
            }
        } 

        // Start/stop the listener 
        ///  
        ///    
        ///       Starts listening to network requests. 
        ///    
        /// 
        public void Start() {
            Start((int)SocketOptionName.MaxConnections); 
        }
 
        public void Start(int backlog) { 
            if (backlog > (int)SocketOptionName.MaxConnections || backlog < 0) {
                throw new ArgumentOutOfRangeException("backlog"); 
            }

            if(Logging.On)Logging.Enter(Logging.Sockets, this, "Start", null);
            GlobalLog.Print("TCPListener::Start()"); 

            if (m_ServerSocket == null) 
                throw new InvalidOperationException(SR.GetString(SR.net_InvalidSocketHandle)); 

            //already listening 
            if (m_Active) {
                if(Logging.On)Logging.Exit(Logging.Sockets, this, "Start", null);
                return;
            } 

            m_ServerSocket.Bind(m_ServerSocketEP); 
            try { 
                m_ServerSocket.Listen(backlog);
            } 
            // When there is an exception unwind previous actions (bind etc)
            catch (SocketException) {
                Stop();
                throw; 
            }
            m_Active = true; 
            if(Logging.On)Logging.Exit(Logging.Sockets, this, "Start", null); 
        }
 

        /// 
        ///    
        ///       Closes the network connection. 
        ///    
        ///  
        public void Stop() { 
            if(Logging.On)Logging.Enter(Logging.Sockets, this, "Stop", null);
            GlobalLog.Print("TCPListener::Stop()"); 

            if (m_ServerSocket != null) {
                m_ServerSocket.Close();
                m_ServerSocket = null; 
            }
            m_Active = false; 
            m_ServerSocket = new Socket(m_ServerSocketEP.AddressFamily, SocketType.Stream, ProtocolType.Tcp); 

            if (m_ExclusiveAddressUse) { 
                m_ServerSocket.ExclusiveAddressUse = true;
            }

            if(Logging.On)Logging.Exit(Logging.Sockets, this, "Stop", null); 
        }
 
        // Determine if there are pending connections 
        /// 
        ///     
        ///       Determine if there are pending connection requests.
        ///    
        /// 
        public bool Pending() { 
            if (!m_Active)
                throw new InvalidOperationException(SR.GetString(SR.net_stopped)); 
            return m_ServerSocket.Poll(0, SelectMode.SelectRead); 
        }
 
        // Accept the first pending connection
        /// 
        ///    
        ///       Accepts a pending connection request. 
        ///    
        ///  
        public Socket AcceptSocket() { 
            if(Logging.On)Logging.Enter(Logging.Sockets, this, "AcceptSocket", null);
            if (!m_Active) 
                throw new InvalidOperationException(SR.GetString(SR.net_stopped));
            Socket socket = m_ServerSocket.Accept();
            if(Logging.On)Logging.Exit(Logging.Sockets, this, "AcceptSocket", socket);
            return socket; 
        }
 
        // UEUE 
        /// 
        ///    [To be supplied.] 
        /// 
        public TcpClient AcceptTcpClient() {
            if(Logging.On)Logging.Enter(Logging.Sockets, this, "AcceptTcpClient", null);
            if (!m_Active) 
                throw new InvalidOperationException(SR.GetString(SR.net_stopped));
 
            Socket acceptedSocket = m_ServerSocket.Accept(); 
            TcpClient returnValue = new TcpClient(acceptedSocket);
            if(Logging.On)Logging.Exit(Logging.Sockets, this, "AcceptTcpClient", returnValue); 
            return returnValue;
        }

 

        //methods 
 
        [HostProtection(ExternalThreading=true)]
        public IAsyncResult BeginAcceptSocket(AsyncCallback callback, object state) 
        {
            if(Logging.On)Logging.Enter(Logging.Sockets, this, "BeginAcceptSocket", null);
            if (!m_Active)
                throw new InvalidOperationException(SR.GetString(SR.net_stopped)); 

            IAsyncResult result = m_ServerSocket.BeginAccept(callback,state); 
            if(Logging.On)Logging.Exit(Logging.Sockets, this, "BeginAcceptSocket", null); 
            return result;
        } 

        public Socket EndAcceptSocket(IAsyncResult asyncResult){
            if(Logging.On)Logging.Enter(Logging.Sockets, this, "EndAcceptSocket", null);
 
            if (asyncResult == null)
            { 
                throw new ArgumentNullException("asyncResult"); 
            }
 
            LazyAsyncResult lazyResult = asyncResult as LazyAsyncResult;
            Socket asyncSocket = lazyResult == null ? null : lazyResult.AsyncObject as Socket;
            if (asyncSocket == null)
            { 
                throw new ArgumentException(SR.GetString(SR.net_io_invalidasyncresult), "asyncResult");
            } 
 
            // This will throw ObjectDisposedException if Stop() has been called.
            Socket socket = asyncSocket.EndAccept(asyncResult); 

            if(Logging.On)Logging.Exit(Logging.Sockets, this, "EndAcceptSocket", socket);
            return socket;
        } 

        [HostProtection(ExternalThreading=true)] 
        public IAsyncResult BeginAcceptTcpClient(AsyncCallback callback, object state) 
        {
            if(Logging.On)Logging.Enter(Logging.Sockets, this, "BeginAcceptTcpClient", null); 
            if (!m_Active)
                throw new InvalidOperationException(SR.GetString(SR.net_stopped));
            IAsyncResult result = m_ServerSocket.BeginAccept(callback,state);
            if(Logging.On)Logging.Exit(Logging.Sockets, this, "BeginAcceptTcpClient", null); 
            return result;
        } 
 
        public TcpClient EndAcceptTcpClient(IAsyncResult asyncResult){
            if(Logging.On)Logging.Enter(Logging.Sockets, this, "EndAcceptTcpClient", null); 

            if (asyncResult == null)
            {
                throw new ArgumentNullException("asyncResult"); 
            }
 
            LazyAsyncResult lazyResult = asyncResult as LazyAsyncResult; 
            Socket asyncSocket = lazyResult == null ? null : lazyResult.AsyncObject as Socket;
            if (asyncSocket == null) 
            {
                throw new ArgumentException(SR.GetString(SR.net_io_invalidasyncresult), "asyncResult");
            }
 
            // This will throw ObjectDisposedException if Stop() has been called.
            Socket socket = asyncSocket.EndAccept(asyncResult); 
 
            if(Logging.On)Logging.Exit(Logging.Sockets, this, "EndAcceptTcpClient", socket);
            return new TcpClient(socket); 
        }
    }; // class TcpListener

 
} // namespace System.Net.Sockets

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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TCPListener.cs source code in C# .NET

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