private void Shutdown(Exception?shutdownReason)
{
lock (_shutdownLock)
{
if (_socketDisposed)
{
return;
}
// Make sure to close the connection only after the _aborted flag is set.
// Without this, the RequestsCanBeAbortedMidRead test will sometimes fail when
// a BadHttpRequestException is thrown instead of a TaskCanceledException.
_socketDisposed = true;
// shutdownReason should only be null if the output was completed gracefully, so no one should ever
// ever observe the nondescript ConnectionAbortedException except for connection middleware attempting
// to half close the connection which is currently unsupported.
_shutdownReason = shutdownReason ?? new ConnectionAbortedException("The Socket transport's send loop completed gracefully.");
SocketsLog.ConnectionWriteFin(_logger, this, _shutdownReason.Message);
try
{
// Try to gracefully close the socket even for aborts to match libuv behavior.
_socket.Shutdown(SocketShutdown.Both);
}
catch
{
// Ignore any errors from Socket.Shutdown() since we're tearing down the connection anyway.
}
_socket.Dispose();
}
}
private async Task DoSend()
{
Exception?shutdownReason = null;
Exception?unexpectedError = null;
try
{
while (true)
{
var result = await Output.ReadAsync();
if (result.IsCanceled)
{
break;
}
var buffer = result.Buffer;
if (!buffer.IsEmpty)
{
_sender = _socketSenderPool.Rent();
await _sender.SendAsync(_socket, buffer);
// We don't return to the pool if there was an exception, and
// we keep the _sender assigned so that we can dispose it in StartAsync.
_socketSenderPool.Return(_sender);
_sender = null;
}
Output.AdvanceTo(buffer.End);
if (result.IsCompleted)
{
break;
}
}
}
catch (SocketException ex) when(IsConnectionResetError(ex.SocketErrorCode))
{
shutdownReason = new ConnectionResetException(ex.Message, ex);
SocketsLog.ConnectionReset(_logger, this);
}
catch (Exception ex)
when((ex is SocketException socketEx && IsConnectionAbortError(socketEx.SocketErrorCode)) ||
ex is ObjectDisposedException)
{
// This should always be ignored since Shutdown() must have already been called by Abort().
shutdownReason = ex;
}
catch (Exception ex)
{
shutdownReason = ex;
unexpectedError = ex;
SocketsLog.ConnectionError(_logger, this, unexpectedError);
}
finally
{
Shutdown(shutdownReason);
// Complete the output after disposing the socket
Output.Complete(unexpectedError);
// Cancel any pending flushes so that the input loop is un-paused
Input.CancelPendingFlush();
}
}
private async Task DoReceive()
{
Exception?error = null;
try
{
while (true)
{
if (_waitForData)
{
// Wait for data before allocating a buffer.
await _receiver.WaitForDataAsync(_socket);
}
// Ensure we have some reasonable amount of buffer space
var buffer = Input.GetMemory(MinAllocBufferSize);
var bytesReceived = await _receiver.ReceiveAsync(_socket, buffer);
if (bytesReceived == 0)
{
// FIN
SocketsLog.ConnectionReadFin(_logger, this);
break;
}
Input.Advance(bytesReceived);
var flushTask = Input.FlushAsync();
var paused = !flushTask.IsCompleted;
if (paused)
{
SocketsLog.ConnectionPause(_logger, this);
}
var result = await flushTask;
if (paused)
{
SocketsLog.ConnectionResume(_logger, this);
}
if (result.IsCompleted || result.IsCanceled)
{
// Pipe consumer is shut down, do we stop writing
break;
}
}
}
catch (SocketException ex) when(IsConnectionResetError(ex.SocketErrorCode))
{
// This could be ignored if _shutdownReason is already set.
error = new ConnectionResetException(ex.Message, ex);
// There's still a small chance that both DoReceive() and DoSend() can log the same connection reset.
// Both logs will have the same ConnectionId. I don't think it's worthwhile to lock just to avoid this.
if (!_socketDisposed)
{
SocketsLog.ConnectionReset(_logger, this);
}
}
catch (Exception ex)
when((ex is SocketException socketEx && IsConnectionAbortError(socketEx.SocketErrorCode)) ||
ex is ObjectDisposedException)
{
// This exception should always be ignored because _shutdownReason should be set.
error = ex;
if (!_socketDisposed)
{
// This is unexpected if the socket hasn't been disposed yet.
SocketsLog.ConnectionError(_logger, this, error);
}
}
catch (Exception ex)
{
// This is unexpected.
error = ex;
SocketsLog.ConnectionError(_logger, this, error);
}
finally
{
// If Shutdown() has already bee called, assume that was the reason ProcessReceives() exited.
Input.Complete(_shutdownReason ?? error);
FireConnectionClosed();
await _waitForConnectionClosedTcs.Task;
}
}