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Fixes "InvalidOperationException" errors by performing async operations in SemaphoreSlim #796

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Original file line number Diff line number Diff line change
Expand Up @@ -442,6 +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\SslOverTdsStream.cs" />
<Compile Include="Microsoft\Data\SqlClient\SNI\SNICommon.cs" />
<Compile Include="Microsoft\Data\SqlClient\SNI\SspiClientContextStatus.cs" />
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -93,7 +93,7 @@ public SNINpHandle(string serverName, string pipeName, long timerExpire, object
}

_sslOverTdsStream = new SslOverTdsStream(_pipeStream);
_sslStream = new SslStream(_sslOverTdsStream, true, new RemoteCertificateValidationCallback(ValidateServerCertificate), null);
_sslStream = new SNISslStream(_sslOverTdsStream, true, new RemoteCertificateValidationCallback(ValidateServerCertificate));

_stream = _pipeStream;
_status = TdsEnums.SNI_SUCCESS;
Expand Down
Original file line number Diff line number Diff line change
@@ -0,0 +1,44 @@
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System.Net.Security;
using System.IO;
using System.Threading;
using System.Threading.Tasks;

namespace Microsoft.Data.SqlClient.SNI
{
/// <summary>
/// This class extends SslStream to customize stream behavior for Managed SNI implementation.
/// </summary>
internal class SNISslStream : SslStream
{
private readonly ConcurrentQueueSemaphore _writeQueueSemaphore;
private readonly ConcurrentQueueSemaphore _readQueueSemaphore;

public SNISslStream(Stream innerStream, bool leaveInnerStreamOpen, RemoteCertificateValidationCallback userCertificateValidationCallback)
: base(innerStream, leaveInnerStreamOpen, userCertificateValidationCallback)
{
_writeQueueSemaphore = new ConcurrentQueueSemaphore(1);
_readQueueSemaphore = 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)
{
_readQueueSemaphore.Wait();
Task<int> t = base.ReadAsync(buffer, offset, count, cancellationToken);
_readQueueSemaphore.Release();
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return t;
}

// Prevent the WriteAsync's collision by running task in Semaphore Slim
public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
{
_writeQueueSemaphore.Wait();
return base.WriteAsync(buffer, offset, count, cancellationToken)
.ContinueWith(t => _writeQueueSemaphore.Release());
}
}
}
Original file line number Diff line number Diff line change
Expand Up @@ -160,14 +160,14 @@ public SNITCPHandle(string serverName, int port, long timerExpire, object callba
{
// Retry with cached IP address
if (ex is SocketException || ex is ArgumentException || ex is AggregateException)
{
{
if (hasCachedDNSInfo == false)
{
throw;
}
else
{
int portRetry = String.IsNullOrEmpty(cachedDNSInfo.Port) ? port : Int32.Parse(cachedDNSInfo.Port);
int portRetry = String.IsNullOrEmpty(cachedDNSInfo.Port) ? port : Int32.Parse(cachedDNSInfo.Port);

try
{
Expand All @@ -180,9 +180,9 @@ public SNITCPHandle(string serverName, int port, long timerExpire, object callba
_socket = Connect(cachedDNSInfo.AddrIPv4, portRetry, ts, isInfiniteTimeOut, cachedFQDN, ref pendingDNSInfo);
}
}
catch(Exception exRetry)
catch (Exception exRetry)
{
if (exRetry is SocketException || exRetry is ArgumentNullException
if (exRetry is SocketException || exRetry is ArgumentNullException
|| exRetry is ArgumentException || exRetry is ArgumentOutOfRangeException || exRetry is AggregateException)
{
if (parallel)
Expand All @@ -199,7 +199,7 @@ public SNITCPHandle(string serverName, int port, long timerExpire, object callba
throw;
}
}
}
}
}
else
{
Expand All @@ -226,7 +226,7 @@ public SNITCPHandle(string serverName, int port, long timerExpire, object callba
_tcpStream = new NetworkStream(_socket, true);

_sslOverTdsStream = new SslOverTdsStream(_tcpStream);
_sslStream = new SslStream(_sslOverTdsStream, true, new RemoteCertificateValidationCallback(ValidateServerCertificate), null);
_sslStream = new SNISslStream(_sslOverTdsStream, true, new RemoteCertificateValidationCallback(ValidateServerCertificate));
}
catch (SocketException se)
{
Expand Down Expand Up @@ -331,7 +331,7 @@ private static Socket Connect(string serverName, int port, TimeSpan timeout, boo
}

CancellationTokenSource cts = null;

void Cancel()
{
for (int i = 0; i < sockets.Length; ++i)
Expand All @@ -355,7 +355,7 @@ void Cancel()
}

Socket availableSocket = null;
try
try
{
for (int i = 0; i < sockets.Length; ++i)
{
Expand Down Expand Up @@ -706,12 +706,17 @@ public override void SetAsyncCallbacks(SNIAsyncCallback receiveCallback, SNIAsyn
/// <returns>SNI error code</returns>
public override uint SendAsync(SNIPacket packet, SNIAsyncCallback callback = null)
{
SNIAsyncCallback cb = callback ?? _sendCallback;
lock (this)
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long scopeID = SqlClientEventSource.Log.TrySNIScopeEnterEvent("<sc.SNI.SNIMarsHandle.SendAsync |SNI|INFO|SCOPE>");
try
{
SNIAsyncCallback cb = callback ?? _sendCallback;
packet.WriteToStreamAsync(_stream, cb, SNIProviders.TCP_PROV);
return TdsEnums.SNI_SUCCESS_IO_PENDING;
}
finally
{
SqlClientEventSource.Log.TrySNIScopeLeaveEvent(scopeID);
}
return TdsEnums.SNI_SUCCESS_IO_PENDING;
}

/// <summary>
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -12,24 +12,16 @@ namespace Microsoft.Data.SqlClient.SNI
internal sealed partial class SslOverTdsStream
{
public override int Read(byte[] buffer, int offset, int count)
{
return Read(buffer.AsSpan(offset, count));
}
=> Read(buffer.AsSpan(offset, count));

public override void Write(byte[] buffer, int offset, int count)
{
Write(buffer.AsSpan(offset, count));
}
=> Write(buffer.AsSpan(offset, count));

public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
{
return ReadAsync(new Memory<byte>(buffer, offset, count), cancellationToken).AsTask();
}
=> ReadAsync(new Memory<byte>(buffer, offset, count), cancellationToken).AsTask();

public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
{
return WriteAsync(new ReadOnlyMemory<byte>(buffer, offset, count), cancellationToken).AsTask();
}
=> WriteAsync(new ReadOnlyMemory<byte>(buffer, offset, count), cancellationToken).AsTask();

public override int Read(Span<byte> buffer)
{
Expand Down Expand Up @@ -288,7 +280,6 @@ public override async ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, Cancella

await _stream.FlushAsync().ConfigureAwait(false);


remaining = remaining.Slice(dataLength);
}
}
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@
// See the LICENSE file in the project root for more information.

using System;
using System.Collections.Concurrent;
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using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
Expand Down Expand Up @@ -2131,4 +2132,48 @@ public static MethodInfo GetPromotedToken
}
}
}

/// <summary>
/// This class implements a FIFO Queue with SemaphoreSlim for ordered execution of parallel tasks.
/// Currently used in Managed SNI (SNISslStream) to override SslStream's WriteAsync implementation.
/// </summary>
internal class ConcurrentQueueSemaphore
{
private readonly SemaphoreSlim _semaphore;
private readonly ConcurrentQueue<TaskCompletionSource<bool>> _queue =
new ConcurrentQueue<TaskCompletionSource<bool>>();

public ConcurrentQueueSemaphore(int initialCount)
{
_semaphore = new SemaphoreSlim(initialCount);
}

public ConcurrentQueueSemaphore(int initialCount, int maxCount)
{
_semaphore = new SemaphoreSlim(initialCount, maxCount);
}

public void Wait()
{
WaitAsync().Wait();
}

public Task WaitAsync()
{
var tcs = new TaskCompletionSource<bool>();
_queue.Enqueue(tcs);
_semaphore.WaitAsync().ContinueWith(t =>
{
if (_queue.TryDequeue(out TaskCompletionSource<bool> popped))
popped.SetResult(true);
});
return tcs.Task;
}
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public void Release()
{
_semaphore.Release();
}
}

}//namespace
Original file line number Diff line number Diff line change
Expand Up @@ -3266,7 +3266,7 @@ internal Task WritePacket(byte flushMode, bool canAccumulate = false)

if (willCancel)
{
// If we have been cancelled, then ensure that we write the ATTN packet as well
// If we have been canceled, then ensure that we write the ATTN packet as well
task = AsyncHelper.CreateContinuationTask(task, CancelWritePacket);
}
return task;
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -72,13 +72,13 @@ internal override void AssignPendingDNSInfo(string userProtocol, string DNSCache
internal void ReadAsyncCallback(SNIPacket packet, uint error)
{
ReadAsyncCallback(IntPtr.Zero, PacketHandle.FromManagedPacket(packet), error);
_sessionHandle.ReturnPacket(packet);
_sessionHandle?.ReturnPacket(packet);
}

internal void WriteAsyncCallback(SNIPacket packet, uint sniError)
{
WriteAsyncCallback(IntPtr.Zero, PacketHandle.FromManagedPacket(packet), sniError);
_sessionHandle.ReturnPacket(packet);
_sessionHandle?.ReturnPacket(packet);
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}

protected override void RemovePacketFromPendingList(PacketHandle packet)
Expand Down