private Task ProcessWindowUpdateFrameAsync()
{
if (_currentHeadersStream != null)
{
throw new Http2ConnectionErrorException(CoreStrings.FormatHttp2ErrorHeadersInterleaved(_incomingFrame.Type, _incomingFrame.StreamId, _currentHeadersStream.StreamId), Http2ErrorCode.PROTOCOL_ERROR);
}
if (_incomingFrame.Length != 4)
{
throw new Http2ConnectionErrorException(CoreStrings.FormatHttp2ErrorUnexpectedFrameLength(_incomingFrame.Type, 4), Http2ErrorCode.FRAME_SIZE_ERROR);
}
ThrowIfIncomingFrameSentToIdleStream();
if (_incomingFrame.WindowUpdateSizeIncrement == 0)
{
// http://httpwg.org/specs/rfc7540.html#rfc.section.6.9
// A receiver MUST treat the receipt of a WINDOW_UPDATE
// frame with an flow-control window increment of 0 as a
// stream error (Section 5.4.2) of type PROTOCOL_ERROR;
// errors on the connection flow-control window MUST be
// treated as a connection error (Section 5.4.1).
//
// http://httpwg.org/specs/rfc7540.html#rfc.section.5.4.1
// An endpoint can end a connection at any time. In
// particular, an endpoint MAY choose to treat a stream
// error as a connection error.
//
// Since server initiated stream resets are not yet properly
// implemented and tested, we treat all zero length window
// increments as connection errors for now.
throw new Http2ConnectionErrorException(CoreStrings.Http2ErrorWindowUpdateIncrementZero, Http2ErrorCode.PROTOCOL_ERROR);
}
if (_incomingFrame.StreamId == 0)
{
if (!_frameWriter.TryUpdateConnectionWindow(_incomingFrame.WindowUpdateSizeIncrement))
{
throw new Http2ConnectionErrorException(CoreStrings.Http2ErrorWindowUpdateSizeInvalid, Http2ErrorCode.FLOW_CONTROL_ERROR);
}
}
else if (_streams.TryGetValue(_incomingFrame.StreamId, out var stream))
{
if (!stream.TryUpdateOutputWindow(_incomingFrame.WindowUpdateSizeIncrement))
{
throw new Http2StreamErrorException(_incomingFrame.StreamId, CoreStrings.Http2ErrorWindowUpdateSizeInvalid, Http2ErrorCode.FLOW_CONTROL_ERROR);
}
}
else
{
// The stream was not found in the dictionary which means the stream was probably closed. This can
// happen when the client sends a window update for a stream right as the server closes the same stream
// Since this is an unavoidable race, we just ignore the window update frame.
}
return(Task.CompletedTask);
}
