Implementing SNINetworkStream fixes issue 422 for non-encrypted TCP connections.

Author: cheenamalhotra

src/Microsoft.Data.SqlClient/netcore/src/Microsoft.Data.SqlClient.csproj

@@ -442,7 +442,7 @@
     <Compile Include="Microsoft\Data\SqlClient\SNI\SNIPhysicalHandle.cs" />
     <Compile Include="Microsoft\Data\SqlClient\SNI\SNIProxy.cs" />
     <Compile Include="Microsoft\Data\SqlClient\SNI\SNITcpHandle.cs" />
-    <Compile Include="Microsoft\Data\SqlClient\SNI\SNISslStream.cs" />
+    <Compile Include="Microsoft\Data\SqlClient\SNI\SNIStreams.cs" />
     <Compile Include="Microsoft\Data\SqlClient\SNI\SslOverTdsStream.cs" />
     <Compile Include="Microsoft\Data\SqlClient\SNI\SNICommon.cs" />
     <Compile Include="Microsoft\Data\SqlClient\SNI\SspiClientContextStatus.cs" />

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SNI/SNISslStream.cs src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SNI/SNIStreams.cs

@@ -6,6 +6,7 @@
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
+using System.Net.Sockets;
 
 namespace Microsoft.Data.SqlClient.SNI
 {
@@ -30,7 +31,49 @@ public override Task<int> ReadAsync(byte[] buffer, int offset, int count, Cancel
             try
             {
                 return _readAsyncQueueSemaphore.WaitAsync()
-                    .ContinueWith<int>(_ => base.ReadAsync(buffer, offset, count, cancellationToken).GetAwaiter().GetResult());
+                    .ContinueWith(_ => base.ReadAsync(buffer, offset, count, cancellationToken).GetAwaiter().GetResult());
+            }
+            finally
+            {
+                _readAsyncQueueSemaphore.Release();
+            }
+        }
+
+        // Prevent the WriteAsync's collision by running task in Semaphore Slim
+        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        {
+            try
+            {
+                return _writeAsyncQueueSemaphore.WaitAsync().ContinueWith(_ => base.WriteAsync(buffer, offset, count, cancellationToken));
+            }
+            finally
+            {
+                _writeAsyncQueueSemaphore.Release();
+            }
+        }
+    }
+
+    /// <summary>
+    /// This class extends NetworkStream to customize stream behavior for Managed SNI implementation.
+    /// </summary>
+    internal class SNINetworkStream : NetworkStream
+    {
+        private readonly ConcurrentQueueSemaphore _writeAsyncQueueSemaphore;
+        private readonly ConcurrentQueueSemaphore _readAsyncQueueSemaphore;
+
+        public SNINetworkStream(Socket socket, bool ownsSocket) : base(socket, ownsSocket)
+        {
+            _writeAsyncQueueSemaphore = new ConcurrentQueueSemaphore(1);
+            _readAsyncQueueSemaphore = new ConcurrentQueueSemaphore(1);
+        }
+
+        // Prevent the ReadAsync's collision by running task in Semaphore Slim
+        public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        {
+            try
+            {
+                return _readAsyncQueueSemaphore.WaitAsync()
+                    .ContinueWith(_ => base.ReadAsync(buffer, offset, count, cancellationToken).GetAwaiter().GetResult());
             }
             finally
             {

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SNI/SNITcpHandle.cs

@@ -223,7 +223,7 @@ public SNITCPHandle(string serverName, int port, long timerExpire, object callba
                 }
 
                 _socket.NoDelay = true;
-                _tcpStream = new NetworkStream(_socket, true);
+                _tcpStream = new SNINetworkStream(_socket, true);
 
                 _sslOverTdsStream = new SslOverTdsStream(_tcpStream);
                 _sslStream = new SNISslStream(_sslOverTdsStream, true, new RemoteCertificateValidationCallback(ValidateServerCertificate));