Add implicit FTPS

DearFTP/Configurations/Configuration.cs

@@ -66,6 +66,12 @@ namespace DearFTP.Configurations
                 return false;
             }
 
+            if (Server.ImplicitFtpsPort != 0 && !Tls.AllowTls)
+            {
+                Console.WriteLine("Implicit FTPS is activated but TLS is not allowed");
+                return false;
+            }
+
             if (Tls.AllowTls)
             {
                 if (string.IsNullOrWhiteSpace(Tls.CertificatePath))

DearFTP/Configurations/ServerConfiguration.cs

@@ -8,6 +8,7 @@ namespace DearFTP.Configurations
     {
         public ushort Port { get; set; } = 21;
         public ushort ForceDataPort { get; set; } = 0;
+        public ushort ImplicitFtpsPort { get; set; } = 0;
         public string MOTD { get; set; } = "DearFTP v0.1";
         public string LoginMessage { get; set; } = "Logged in as %user%";
 

DearFTP/FtpServer.cs

@@ -21,6 +21,7 @@ namespace DearFTP
 
         private bool _isRunning = true;
         private TcpListener _listener;
+        private TcpListener _ftpsListener;
 
         public FtpServer()
         {
@@ -39,13 +40,22 @@ namespace DearFTP
             Logger.Log("DearFTP started");
             Logger.Log();
 
+            int implicitFtpsPort = Configuration.Server.ImplicitFtpsPort;
+
+            if (implicitFtpsPort != 0)
+            {
+                Task.Run(() => FtpsTcpLoop());
+            }
+
             TcpLoop();
+
         }
 
         public void Stop()
         {
             _isRunning = false;
             _listener.Stop();
+            _ftpsListener?.Stop();
             StaticDataConnection.Stop();
         }
 
@@ -64,12 +74,33 @@ namespace DearFTP
             }
         }
 
-        private void CreateSession(TcpClient client)
+        private void FtpsTcpLoop()
+        {
+            _ftpsListener = new TcpListener(IPAddress.Any, Configuration.Server.ImplicitFtpsPort);
+            _ftpsListener.Start(5);
+
+            Logger.Log($"Listening on: {_ftpsListener.LocalEndpoint}");
+
+            while (_isRunning)
+            {
+                var client = _ftpsListener.AcceptTcpClient();
+
+                Task.Run(() => CreateSession(client, true));
+            }
+        }
+
+        private void CreateSession(TcpClient client, bool implicitFtps = false)
         {
             Logger.Log($"Client connected: {client.Client.RemoteEndPoint}");
 
             using (var session = new Session(client))
             {
+                if (implicitFtps)
+                {
+                    session.ActivateTls();
+                    session.DataConnection.ActivateTls();
+                }
+
                 session.Start();
             }
         }