Network,TorHandshakes: handle handshake fail

Previously, TorHandshakes used failwith to raise handshake
failed error. Since we need to catch it, as a result of
replacing generic try-with which lead to a red CI in the
PR, we had to define its special excpetion and catch that.

```
The active test run was aborted. Reason: Test host process crashed :
Unhandled exception. System.Exception: Key handshake failed!

   at
   NOnion.TorHandshakes.NTorHandshake.NOnion-TorHandshakes-IHandshake-GenerateKdfResult(ICreatedCell
   serverSideData) in
   /home/runner/work/NOnion/NOnion/NOnion/TorHandshakes/NTorHandshake.fs:line
   112

      at
      <StartupCode$NOnion>[email protected](Unit
      unitVar) in
      /home/runner/work/NOnion/NOnion/NOnion/Network/TorCircuit.fs:line
      352

         at
	 Microsoft.FSharp.Control.AsyncPrimitives.CallThenInvoke[T,TResult](AsyncActivation`1
	 ctxt, TResult result1, FSharpFunc`2 part2) in
	 F:\workspace\_work\1\s\src\fsharp\FSharp.Core\async.fs:line 398

	    at
	    NOnion.Utility.MailboxResultUtil.TryExecuteAsyncAndReplyAsResult@25-3.Invoke(AsyncActivation`1
	    ctxt) in
	    /home/runner/work/NOnion/NOnion/NOnion/Utility/MailboxUtil.fs:line
	    25

	       at
	       NOnion.Utility.MailboxResultUtil.TryExecuteAsyncAndReplyAsResult@24-6.Invoke(AsyncActivation`1
	       ctxt) in
	       /home/runner/work/NOnion/NOnion/NOnion/Utility/MailboxUtil.fs:line
	       24

	          at
		  <StartupCode$NOnion>[email protected](AsyncActivation`1
		  ctxt) in
		  /home/runner/work/NOnion/NOnion/NOnion/Network/TorCircuit.fs:line
		  965

		     at
		     <StartupCode$NOnion>[email protected](AsyncActivation`1
		     ctxt) in
		     /home/runner/work/NOnion/NOnion/NOnion/Network/TorCircuit.fs:line
		     950

		        at
			<StartupCode$FSharp-Core>[email protected](AsyncActivation`1
			ctxt) in
			F:\workspace\_work\1\s\src\fsharp\FSharp.Core\mailbox.fs:line
			303

			   at
			   Microsoft.FSharp.Control.Trampoline.Execute(FSharpFunc`2
			   firstAction) in
			   F:\workspace\_work\1\s\src\fsharp\FSharp.Core\async.fs:line
			   109

			   --- End of stack trace from previous location
			   where exception was thrown ---

			      at
			      [email protected](ExceptionDispatchInfo
			      edi) in
			      F:\workspace\_work\1\s\src\fsharp\FSharp.Core\async.fs:line
			      907

			         at
				 Microsoft.FSharp.Control.Trampoline.Execute(FSharpFunc`2
				 firstAction) in
				 F:\workspace\_work\1\s\src\fsharp\FSharp.Core\async.fs:line
				 109

				    at
				    <StartupCode$FSharp-Core>[email protected](Object
				    o) in
				    F:\workspace\_work\1\s\src\fsharp\FSharp.Core\async.fs:line
				    165

				       at
				       System.Threading.QueueUserWorkItemCallback.Execute()

				          at
					  System.Threading.ThreadPoolWorkQueue.Dispatch()
```

Author: parhamsaremi

NOnion/Exceptions.fs

@@ -29,6 +29,9 @@ type CircuitDestroyedException internal (reason: DestroyReason) =
 type CircuitDecryptionFailedException internal () =
     inherit NOnionException(sprintf "Circuit Decryption Failed")
 
+type HandshakeFailedException internal () =
+    inherit NOnionException(sprintf "Key handshake failed!")
+
 type TimeoutErrorException internal () =
     inherit NOnionException("Time limit exceeded for operation")
 

NOnion/Network/TorGuard.fs

@@ -193,6 +193,18 @@ type TorGuard private (client: TcpClient, sslStream: SslStream) =
     member self.SendAsync (circuidId: uint16) (cellToSend: ICell) =
         self.Send circuidId cellToSend |> Async.StartAsTask
 
+    member private self.HandleIncomingCellException<'T when 'T :> NOnionException>
+        (cell: ICell)
+        (ex: 'T)
+        =
+        sprintf
+            "TorGuard: exception when trying to handle incoming cell type=%i, ex=%s"
+            cell.Command
+            (ex.ToString())
+        |> TorLogger.Log
+
+        self.KillChildCircuits()
+
     member private __.ReceiveInternal() =
         async {
             (*
@@ -332,14 +344,14 @@ type TorGuard private (client: TcpClient, sslStream: SslStream) =
                             try
                                 do! circuit.HandleIncomingCell cell
                             with
+                            | :? HandshakeFailedException as ex ->
+                                self.HandleIncomingCellException<HandshakeFailedException>
+                                    cell
+                                    ex
                             | :? CircuitDecryptionFailedException as ex ->
-                                sprintf
-                                    "TorGuard: exception when trying to handle incoming cell type=%i, ex=%s"
-                                    cell.Command
-                                    (ex.ToString())
-                                |> TorLogger.Log
-
-                                self.KillChildCircuits()
+                                self.HandleIncomingCellException<CircuitDecryptionFailedException>
+                                    cell
+                                    ex
                             | ex -> return raise <| FSharpUtil.ReRaise ex
                         | None ->
                             self.KillChildCircuits()

NOnion/TorHandshakes/FastHandshake.fs

@@ -36,6 +36,6 @@ type FastHandshake =
                 |> Kdf.ComputeLegacyKdf
 
             if kdfResult.KeyHandshake <> serverSideData.DerivativeKey then
-                failwith "Key handshake failed!"
+                raise <| HandshakeFailedException()
             else
                 kdfResult

NOnion/TorHandshakes/NTorHandshake.fs

@@ -107,6 +107,6 @@ type NTorHandshake =
             let auth = calculateHmacSha256 authInput Constants.NTorTMac
 
             if auth <> serverSideData.DerivativeKey then
-                failwith "Key handshake failed!"
+                raise <| HandshakeFailedException()
             else
                 Kdf.ComputeRfc5869Kdf secretInput