move tls client hello check

Author: DeagleGross

src/Servers/Kestrel/Core/src/Middleware/TlsListenerMiddleware.cs

@@ -114,6 +114,12 @@ private static ClientHelloParseState TryParseClientHello(ReadOnlySequence<byte>
             return ClientHelloParseState.NotTlsClientHello;
         }
 
+        // byte 6: handshake message type (must be 0x01 for ClientHello)
+        if (!reader.TryRead(out byte handshakeType) || handshakeType != 0x01)
+        {
+            return ClientHelloParseState.NotTlsClientHello;
+        }
+
         // 5 bytes are
         // 1) Handshake (1 byte)
         // 2) Protocol version (2 bytes)
@@ -123,12 +129,6 @@ private static ClientHelloParseState TryParseClientHello(ReadOnlySequence<byte>
             return ClientHelloParseState.NotEnoughData;
         }
 
-        // byte 6: handshake message type (must be 0x01 for ClientHello)
-        if (!reader.TryRead(out byte handshakeType) || handshakeType != 0x01)
-        {
-            return ClientHelloParseState.NotTlsClientHello;
-        }
-
         clientHelloBytes = buffer.Slice(0, 5 + recordLength);
         return ClientHelloParseState.ValidTlsClientHello;
     }

src/Servers/Kestrel/test/InMemory.FunctionalTests/TlsListenerMiddlewareTests.Units.cs

@@ -79,13 +79,8 @@ public async Task RunTlsClientHelloCallbackTest_DeterministinglyReads()
 
         await transportConnection.Input.WriteAsync(new byte[1] { 0x16 });
         var middlewareTask = Task.Run(() => middleware.OnTlsClientHelloAsync(transportConnection));
-        await Task.Delay(TimeSpan.FromMilliseconds(75));
-
         await transportConnection.Input.WriteAsync(new byte[2] { 0x03, 0x01 });
-        await Task.Delay(TimeSpan.FromMilliseconds(75));
-
         await transportConnection.Input.WriteAsync(new byte[2] { 0x00, 0x20 });
-        await Task.Delay(TimeSpan.FromMilliseconds(75));
 
         await transportConnection.Input.CompleteAsync();
 
@@ -96,7 +91,8 @@ public async Task RunTlsClientHelloCallbackTest_DeterministinglyReads()
         // ensuring that we have read limited number of times
         var observableTransport = transportConnection.Transport as ObservableDuplexPipe;
         Assert.NotNull(observableTransport);
-        Assert.True(observableTransport.ReadAsyncCounter is > 2 && observableTransport.ReadAsyncCounter is <= 5);
+        Assert.True(observableTransport.ReadAsyncCounter is >= 2 && observableTransport.ReadAsyncCounter is <= 5,
+            $"Expected ReadAsync() to happen about 2-5 times. Actually happened {observableTransport.ReadAsyncCounter} times.");
     }
 
     private async Task RunTlsClientHelloCallbackTest_WithMultipleSegments(