Add method KeepAlive to SshClient to allow to send dummy KeepAlive requests

Dont allow por forwarding to start or stop if its already started or stopped

Renci.SshClient/Renci.SshClient/ForwardedPort.cs

@@ -12,6 +12,8 @@ namespace Renci.SshClient
 
         public uint ConnectedPort { get; internal set; }
 
+        public bool IsStarted { get; protected set; }
+
         public event EventHandler<ExceptionEventArgs> Exception;
 
         internal ForwardedPort()

Renci.SshClient/Renci.SshClient/ForwardedPortLocal.cs

@@ -16,6 +16,10 @@ namespace Renci.SshClient
         {
             base.Start();
 
+            //  If port already started dont start it again
+            if (this.IsStarted)
+                return;
+
             var ep = new IPEndPoint(Dns.GetHostAddresses("localhost")[0], (int)this.BoundPort);
             this._listener = new TcpListener(ep);
             this._listener.Start();
@@ -53,13 +57,24 @@ namespace Renci.SshClient
                 {
                     this.RaiseExceptionEvent(exp);
                 }
+
+                this.Stop();
             });
+
+            this.IsStarted = true;
         }
 
         public override void Stop()
         {
+            //  If port not started you cant stop it
+            if (!this.IsStarted)
+                return;
+
             this._listener.Stop();
             this._listenerTask.Wait();
+
+            this.IsStarted = false;
+
         }
     }
 }

Renci.SshClient/Renci.SshClient/ForwardedPortRemote.cs

@@ -16,6 +16,10 @@ namespace Renci.SshClient
         {
             base.Start();
 
+            //  If port already started dont start it again
+            if (this.IsStarted)
+                return;
+
             this.Session.RegisterMessageType<RequestFailureMessage>(Messages.MessageTypes.RequestFailure);
             this.Session.RegisterMessageType<RequestSuccessMessage>(Messages.MessageTypes.RequestSuccess);
             this.Session.RegisterMessageType<ChannelOpenMessage>(Messages.MessageTypes.ChannelOpen);
@@ -40,10 +44,16 @@ namespace Renci.SshClient
                 //  If request  failed dont handle channel opening for this request
                 this.Session.ChannelOpenReceived -= Session_ChannelOpening;
             }
+
+            this.IsStarted = true;
         }
 
         public override void Stop()
         {
+            //  If port not started you cant stop it
+            if (!this.IsStarted)
+                return;
+
             //  Send global request to cancel direct tcpip
             this.Session.SendMessage(new GlobalRequestMessage
             {
@@ -58,6 +68,8 @@ namespace Renci.SshClient
             this.Session.RequestSuccessReceived -= Session_RequestSuccess;
             this.Session.RequestFailureReceived -= Session_RequestFailure;
             this.Session.ChannelOpenReceived -= Session_ChannelOpening;
+
+            this.IsStarted = false;
         }
 
         private void Session_ChannelOpening(object sender, MessageEventArgs<ChannelOpenMessage> e)

Renci.SshClient/Renci.SshClient/Messages/Connection/GlobalRequestMessage.cs

@@ -47,12 +47,27 @@ namespace Renci.SshClient.Messages.Connection
                 case GlobalRequestNames.CancelTcpIpForward:
                     this.Write("cancel-tcpip-forward");
                     break;
+                case GlobalRequestNames.KeepAlive:
+                    this.Write("keep-alive-message-ignore-me");
+                    break;
                 default:
                     break;
             }
+
             this.Write(this.WantReply);
-            this.Write(this.AddressToBind);
-            this.Write(this.PortToBind);
+
+            switch (this.RequestName)
+            {
+                case GlobalRequestNames.TcpIpForward:
+                case GlobalRequestNames.CancelTcpIpForward:
+                    this.Write(this.AddressToBind);
+                    this.Write(this.PortToBind);
+                    break;
+                case GlobalRequestNames.KeepAlive:
+                    break;
+                default:
+                    break;
+            }
         }
     }
 }

Renci.SshClient/Renci.SshClient/Messages/Connection/GlobalRequestNames.cs

@@ -9,6 +9,10 @@
         /// <summary>
         /// cancel-tcpip-forward
         /// </summary>
-        CancelTcpIpForward
+        CancelTcpIpForward,
+        /// <summary>
+        /// keep-alive-message-ignore-me
+        /// </summary>
+        KeepAlive
     }
 }

Renci.SshClient/Renci.SshClient/Session.cs

@@ -568,6 +568,18 @@ namespace Renci.SshClient
             return channel;
         }
 
+        /// <summary>
+        /// Sends "keep alive" message to keep connection alive.
+        /// </summary>
+        internal void KeepAlive()
+        {
+            this.SendMessage(new GlobalRequestMessage
+            {
+                RequestName = GlobalRequestNames.KeepAlive,
+                WantReply = false
+            });
+        }
+
         /// <summary>
         /// Waits for handle to signal while checking other handles as well including timeout check to prevent waiting for ever
         /// </summary>

Renci.SshClient/Renci.SshClient/SshClient.cs

@@ -23,23 +23,6 @@ namespace Renci.SshClient
             }
         }
 
-        //private Sftp _sftp;
-        ///// <summary>
-        ///// Gets the shell.
-        ///// </summary>
-        ///// <value>The shell.</value>
-        //public Sftp Sftp
-        //{
-        //    get
-        //    {
-        //        if (this._sftp == null)
-        //        {
-        //            this._sftp = new Sftp(this._session);
-        //        }
-        //        return this._sftp;
-        //    }
-        //}
-
         public IEnumerable<ForwardedPort> ForwardedPorts
         {
             get
@@ -128,6 +111,19 @@ namespace Renci.SshClient
             return port;
         }
 
+        public void RemoveForwardedPort(ForwardedPort port)
+        {
+            //  Stop port forwarding before removing it
+            port.Stop();
+
+            this._forwardedPorts.Remove(port);
+        }
+
+        public void KeepAlive()
+        {
+            this._session.KeepAlive();
+        }
+
         public SshCommand CreateCommand(string commandText)
         {
             return new SshCommand(this._session, commandText);
@@ -145,16 +141,6 @@ namespace Renci.SshClient
             return new Shell(this._session, input, output, extendedOutput, terminalName, columns, rows, width, height, terminalMode);
         }
 
-        //public Sftp CreateSftp()
-        //{
-        //    return new Sftp(this._session);
-        //}
-
-        public void RemoveForwardedPort(ForwardedPort port)
-        {
-            this._forwardedPorts.Remove(port);
-        }
-
         #region IDisposable Members
 
         private bool disposed = false;