Immediately sent identification string when connection is established.

Fixes #689.

Author: drieseng

src/Renci.SshNet.Tests/Classes/SessionTest.cs

@@ -3,9 +3,11 @@
 using System.Net;
 using System.Net.Sockets;
 using System.Text;
+using System.Threading;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Moq;
 using Renci.SshNet.Common;
+using Renci.SshNet.Messages.Transport;
 using Renci.SshNet.Tests.Common;
 using Renci.SshNet.Tests.Properties;
 
@@ -98,6 +100,53 @@ public void ConnectShouldSkipLinesBeforeProtocolIdentificationString()
             }
         }
 
+        [TestMethod]
+        public void ConnectShouldImmediatelySendIdentificationStringWhenConnectionHasBeenEstablised()
+        {
+            var serverEndPoint = new IPEndPoint(IPAddress.Loopback, 8122);
+            var connectionInfo = CreateConnectionInfo(serverEndPoint, TimeSpan.FromSeconds(5));
+
+            using (var serverStub = new AsyncSocketListener(serverEndPoint))
+            {
+                serverStub.Connected += socket =>
+                    {
+                        var identificationBytes = new byte[2048];
+                        var bytesReceived = socket.Receive(identificationBytes);
+
+                        if (bytesReceived > 0)
+                        {
+                            var identificationSttring = Encoding.ASCII.GetString(identificationBytes, 0, bytesReceived);
+                            Console.WriteLine("STRING=" + identificationSttring);
+                            Console.WriteLine("DONE");
+
+                            socket.Send(Encoding.ASCII.GetBytes("\r\n"));
+                            socket.Send(Encoding.ASCII.GetBytes("WELCOME banner\r\n"));
+                            socket.Send(Encoding.ASCII.GetBytes("SSH-666-SshStub\r\n"));
+                        }
+
+                        socket.Shutdown(SocketShutdown.Send);
+                    };
+                serverStub.Start();
+
+                using (var session = new Session(connectionInfo, _serviceFactoryMock.Object))
+                {
+                    try
+                    {
+                        session.Connect();
+                        Assert.Fail();
+                    }
+                    catch (SshConnectionException ex)
+                    {
+                        Assert.IsNull(ex.InnerException);
+                        Assert.AreEqual("Server version '666' is not supported.", ex.Message);
+
+                        Assert.AreEqual("SSH-666-SshStub", connectionInfo.ServerVersion);
+                    }
+                }
+            }
+        }
+
+
         [TestMethod]
         public void ConnectShouldSupportProtocolIdentificationStringThatDoesNotEndWithCrlf()
         {

src/Renci.SshNet/Session.cs

@@ -577,14 +577,14 @@ public void Connect()
 
                 lock (this)
                 {
-                    //  If connected don't connect again
+                    // If connected don't connect again
                     if (IsConnected)
                         return;
 
-                    // reset connection specific information
+                    // Reset connection specific information
                     Reset();
 
-                    //  Build list of available messages while connecting
+                    // Build list of available messages while connecting
                     _sshMessageFactory = new SshMessageFactory();
 
                     switch (ConnectionInfo.ProxyType)
@@ -606,10 +606,14 @@ public void Connect()
                             break;
                     }
 
+                    // Immediately send the identification string since the spec states both sides MUST send an identification string
+                    // when the connection has been established
+                    SocketAbstraction.Send(_socket, Encoding.UTF8.GetBytes(string.Format(CultureInfo.InvariantCulture, "{0}\x0D\x0A", ClientVersion)));
+
                     Match versionMatch;
 
-                    //  Get server version from the server,
-                    //  ignore text lines which are sent before if any
+                    // Get server version from the server,
+                    // ignore text lines which are sent before if any
                     while (true)
                     {
                         var serverVersion = SocketReadLine(_socket, ConnectionInfo.Timeout);
@@ -623,11 +627,11 @@ public void Connect()
                         }
                     }
 
-                    //  Set connection versions
+                    // Set connection versions
                     ConnectionInfo.ServerVersion = ServerVersion;
                     ConnectionInfo.ClientVersion = ClientVersion;
 
-                    //  Get server SSH version
+                    // Get server SSH version
                     var version = versionMatch.Result("${protoversion}");
 
                     var softwareName = versionMatch.Result("${softwareversion}");
@@ -639,9 +643,7 @@ public void Connect()
                         throw new SshConnectionException(string.Format(CultureInfo.CurrentCulture, "Server version '{0}' is not supported.", version), DisconnectReason.ProtocolVersionNotSupported);
                     }
 
-                    SocketAbstraction.Send(_socket, Encoding.UTF8.GetBytes(string.Format(CultureInfo.InvariantCulture, "{0}\x0D\x0A", ClientVersion)));
-
-                    //  Register Transport response messages
+                    // Register Transport response messages
                     RegisterMessage("SSH_MSG_DISCONNECT");
                     RegisterMessage("SSH_MSG_IGNORE");
                     RegisterMessage("SSH_MSG_UNIMPLEMENTED");
@@ -650,29 +652,29 @@ public void Connect()
                     RegisterMessage("SSH_MSG_KEXINIT");
                     RegisterMessage("SSH_MSG_NEWKEYS");
 
-                    //  Some server implementations might sent this message first, prior establishing encryption algorithm
+                    // Some server implementations might sent this message first, prior to establishing encryption algorithm
                     RegisterMessage("SSH_MSG_USERAUTH_BANNER");
 
-                    // mark the message listener threads as started
+                    // Mark the message listener threads as started
                     _messageListenerCompleted.Reset();
 
-                    //  Start incoming request listener
+                    // Start incoming request listener
                     ThreadAbstraction.ExecuteThread(() => MessageListener());
 
-                    //  Wait for key exchange to be completed
+                    // Wait for key exchange to be completed
                     WaitOnHandle(_keyExchangeCompletedWaitHandle);
 
-                    //  If sessionId is not set then its not connected
+                    // If sessionId is not set then its not connected
                     if (SessionId == null)
                     {
                         Disconnect();
                         return;
                     }
 
-                    //  Request user authorization service
+                    // Request user authorization service
                     SendMessage(new ServiceRequestMessage(ServiceName.UserAuthentication));
 
-                    //  Wait for service to be accepted
+                    // Wait for service to be accepted
                     WaitOnHandle(_serviceAccepted);
 
                     if (string.IsNullOrEmpty(ConnectionInfo.Username))
@@ -687,7 +689,7 @@ public void Connect()
                     ConnectionInfo.Authenticate(this, _serviceFactory);
                     _isAuthenticated = true;
 
-                    //  Register Connection messages
+                    // Register Connection messages
                     RegisterMessage("SSH_MSG_REQUEST_SUCCESS");
                     RegisterMessage("SSH_MSG_REQUEST_FAILURE");
                     RegisterMessage("SSH_MSG_CHANNEL_OPEN_CONFIRMATION");
@@ -2003,6 +2005,8 @@ private void MessageListener()
                         break;
                     }
 
+                    Console.WriteLine("RECEIVED MESSAGe " + message.GetType());
+
                     // process message
                     message.Process(this);
                 }