protected override bool AdvanceFrame()
        {
            if (this.currentFrameIdx >= this.frames.Count - 1)
            {
                return(false);
            }

            this.currentFrameIdx++;
            HTTP2FrameHeaderAndPayload frame = this.frames[this.currentFrameIdx];

            this.data = frame.Payload;

            switch (frame.Type)
            {
            case HTTP2FrameTypes.HEADERS:
                var header = HTTP2FrameHelper.ReadHeadersFrame(frame);
                this.offset    = header.HeaderBlockFragmentIdx;
                this.maxOffset = this.offset + header.HeaderBlockFragmentLength;
                break;

            case HTTP2FrameTypes.CONTINUATION:
                this.offset    = 0;
                this.maxOffset = frame.PayloadLength;
                break;
            }

            return(true);
        }
        internal void Process(HTTP2FrameHeaderAndPayload frame, List <HTTP2FrameHeaderAndPayload> outgoingFrames)
        {
            if (frame.Type != HTTP2FrameTypes.SETTINGS)
            {
                return;
            }

            HTTP2SettingsFrame settingsFrame = HTTP2FrameHelper.ReadSettings(frame);

            if (HTTPManager.Logger.Level <= Logger.Loglevels.Information)
            {
                HTTPManager.Logger.Information("HTTP2SettingsManager", "Processing Settings frame: " + settingsFrame.ToString(), this.Parent.Context);
            }

            if ((settingsFrame.Flags & HTTP2SettingsFlags.ACK) == HTTP2SettingsFlags.ACK)
            {
                this.MySettings.Merge(this.InitiatedMySettings);
                this.SettingsChangesSentAt = DateTime.MinValue;
            }
            else
            {
                this.RemoteSettings.Merge(settingsFrame.Settings);
                outgoingFrames.Add(HTTP2FrameHelper.CreateACKSettingsFrame());
            }
        }
        protected override long CalculateDataLengthForFrame(HTTP2FrameHeaderAndPayload frame)
        {
            switch (frame.Type)
            {
            case HTTP2FrameTypes.HEADERS:
                return(HTTP2FrameHelper.ReadHeadersFrame(frame).HeaderBlockFragmentLength);

            case HTTP2FrameTypes.CONTINUATION:
                return(frame.PayloadLength);
            }

            return(0);
        }
        protected override bool AdvanceFrame()
        {
            if (this.currentFrameIdx >= this.frames.Count - 1)
            {
                return(false);
            }

            this.currentFrameIdx++;
            HTTP2FrameHeaderAndPayload frame     = this.frames[this.currentFrameIdx];
            HTTP2DataFrame             dataFrame = HTTP2FrameHelper.ReadDataFrame(frame);

            this.data      = frame.Payload;
            this.offset    = dataFrame.DataIdx;
            this.maxOffset = dataFrame.DataIdx + dataFrame.DataLength;

            return(true);
        }
        internal HTTP2FrameHeaderAndPayload CreateFrame()
        {
            List <KeyValuePair <HTTP2Settings, UInt32> > keyValuePairs = new List <KeyValuePair <HTTP2Settings, uint> >(HTTP2SettingsManager.SettingsCount);

            for (int i = 1; i < HTTP2SettingsManager.SettingsCount; ++i)
            {
                if (this.changeFlags[i])
                {
                    keyValuePairs.Add(new KeyValuePair <HTTP2Settings, uint>((HTTP2Settings)i, this[(HTTP2Settings)i]));
                    this.changeFlags[i] = false;
                }
            }

            this.IsChanged = false;

            return(HTTP2FrameHelper.CreateSettingsFrame(keyValuePairs));
        }
        public void Process(List <HTTP2FrameHeaderAndPayload> outgoingFrames)
        {
            if (this.AssignedRequest.IsCancellationRequested && !this.isRSTFrameSent)
            {
                // These two are already set in HTTPRequest's Abort().
                //this.AssignedRequest.Response = null;
                //this.AssignedRequest.State = this.AssignedRequest.IsTimedOut ? HTTPRequestStates.TimedOut : HTTPRequestStates.Aborted;

                this.outgoing.Clear();
                if (this.State != HTTP2StreamStates.Idle)
                {
                    this.outgoing.Enqueue(HTTP2FrameHelper.CreateRSTFrame(this.Id, HTTP2ErrorCodes.CANCEL));
                }

                // We can close the stream if already received headers, or not even sent one
                if (this.State == HTTP2StreamStates.HalfClosedRemote || this.State == HTTP2StreamStates.Idle)
                {
                    this.State = HTTP2StreamStates.Closed;
                }

                this.isRSTFrameSent = true;
            }

            // 1.) Go through incoming frames
            ProcessIncomingFrames(outgoingFrames);

            // 2.) Create outgoing frames based on the stream's state and the request processing state.
            ProcessState(outgoingFrames);

            // 3.) Send one frame per Process call
            if (this.outgoing.Count > 0)
            {
                HTTP2FrameHeaderAndPayload frame = this.outgoing.Dequeue();

                outgoingFrames.Add(frame);

                // If END_Stream in header or data frame is present => half closed local
                if ((frame.Type == HTTP2FrameTypes.HEADERS && (frame.Flags & (byte)HTTP2HeadersFlags.END_STREAM) != 0) ||
                    (frame.Type == HTTP2FrameTypes.DATA && (frame.Flags & (byte)HTTP2DataFlags.END_STREAM) != 0))
                {
                    this.State = HTTP2StreamStates.HalfClosedLocal;
                }
            }
        }
 protected override long CalculateDataLengthForFrame(HTTP2FrameHeaderAndPayload frame)
 {
     return(HTTP2FrameHelper.ReadDataFrame(frame).DataLength);
 }
예제 #8
0
        private void ProcessIncomingFrames(List <HTTP2FrameHeaderAndPayload> outgoingFrames)
        {
            UInt32 windowUpdate = 0;

            while (this.incomingFrames.Count > 0)
            {
                HTTP2FrameHeaderAndPayload frame = this.incomingFrames.Dequeue();

                if (this.isRSTFrameSent)
                {
                    BufferPool.Release(frame.Payload);
                    continue;
                }

                if (/*HTTPManager.Logger.Level == Logger.Loglevels.All && */ frame.Type != HTTP2FrameTypes.DATA && frame.Type != HTTP2FrameTypes.WINDOW_UPDATE)
                {
                    HTTPManager.Logger.Information("HTTP2Stream", string.Format("[{0}] Process - processing frame: {1}", this.Id, frame.ToString()));
                }

                switch (frame.Type)
                {
                case HTTP2FrameTypes.HEADERS:
                case HTTP2FrameTypes.CONTINUATION:
                    if (this.State != HTTP2StreamStates.HalfClosedLocal)
                    {
                        // ERROR!
                        continue;
                    }

                    // payload will be released by the view
                    frame.DontUseMemPool = true;

                    if (this.currentFramesView == null)
                    {
                        this.currentFramesView = new FramesAsStreamView(new HeaderFrameView());
                    }

                    this.currentFramesView.AddFrame(frame);

                    if ((frame.Flags & (byte)HTTP2HeadersFlags.END_HEADERS) != 0)
                    {
                        List <KeyValuePair <string, string> > headers = new List <KeyValuePair <string, string> >();

                        try
                        {
                            this.encoder.Decode(this, this.currentFramesView, headers);
                        }
                        catch (Exception ex)
                        {
                            HTTPManager.Logger.Exception("HTTP2Stream", string.Format("[{0}] ProcessIncomingFrames", this.Id), ex);
                        }

                        this.response = new HTTP2Response(this.AssignedRequest, false);
                        this.response.AddHeaders(headers);

                        this.AssignedRequest.Response = this.response;

                        this.currentFramesView.Close();
                        this.currentFramesView = null;

                        if (frame.Type == HTTP2FrameTypes.HEADERS && (frame.Flags & (byte)HTTP2HeadersFlags.END_STREAM) != 0)
                        {
                            PlatformSupport.Threading.ThreadedRunner.RunShortLiving <HTTPRequest, HTTP2Response, FramesAsStreamView>(FinishRequest, this.AssignedRequest, this.response, this.currentFramesView);

                            if (this.State == HTTP2StreamStates.HalfClosedLocal)
                            {
                                this.State = HTTP2StreamStates.Closed;
                            }
                            else
                            {
                                this.State = HTTP2StreamStates.HalfClosedRemote;
                            }
                        }
                    }
                    break;

                case HTTP2FrameTypes.DATA:
                    if (this.State != HTTP2StreamStates.HalfClosedLocal)
                    {
                        // ERROR!
                        continue;
                    }

                    this.downloaded += frame.PayloadLength;

                    if (this.isStreamedDownload && frame.Payload != null && frame.PayloadLength > 0)
                    {
                        this.response.ProcessData(frame.Payload, (int)frame.PayloadLength);
                    }

                    // frame's buffer will be released by the frames view
                    frame.DontUseMemPool = true;

                    if (this.currentFramesView == null && !this.isStreamedDownload)
                    {
                        this.currentFramesView = new FramesAsStreamView(new DataFrameView());
                    }

                    if (!this.isStreamedDownload)
                    {
                        this.currentFramesView.AddFrame(frame);
                    }

                    // Track received data, and if necessary(local window getting too low), send a window update frame
                    if (this.localWindow < frame.PayloadLength)
                    {
                        HTTPManager.Logger.Error("HTTP2Stream", string.Format("[{0}] Frame's PayloadLength ({1:N0}) is larger then local window ({2:N0}). Frame: {3}", this.Id, frame.PayloadLength, this.localWindow, frame));
                    }
                    else
                    {
                        this.localWindow -= frame.PayloadLength;
                    }

                    bool isFinalDataFrame = (frame.Flags & (byte)HTTP2DataFlags.END_STREAM) != 0;

                    // Window update logic.
                    //  1.) We could use a logic to only send window update(s) after a threshold is reached.
                    //      When the initial window size is high enough to contain the whole or most of the result,
                    //      sending back two window updates (connection and stream) after every data frame is pointless.
                    //  2.) On the other hand, window updates are cheap and works even when initial window size is low.
                    //          (
                    if (isFinalDataFrame || this.localWindow <= this.windowUpdateThreshold)
                    {
                        windowUpdate += this.settings.MySettings[HTTP2Settings.INITIAL_WINDOW_SIZE] - this.localWindow - windowUpdate;
                    }

                    if (isFinalDataFrame)
                    {
                        if (this.isStreamedDownload)
                        {
                            this.response.FinishProcessData();
                        }

                        HTTPManager.Logger.Information("HTTP2Stream", string.Format("[{0}] All data arrived, data length: {1:N0}", this.Id, this.downloaded));

                        // create a short living thread to process the downloaded data:
                        PlatformSupport.Threading.ThreadedRunner.RunShortLiving <HTTPRequest, HTTP2Response, FramesAsStreamView>(FinishRequest, this.AssignedRequest, this.response, this.currentFramesView);

                        this.currentFramesView = null;

                        if (this.State == HTTP2StreamStates.HalfClosedLocal)
                        {
                            this.State = HTTP2StreamStates.Closed;
                        }
                        else
                        {
                            this.State = HTTP2StreamStates.HalfClosedRemote;
                        }
                    }
                    else if (this.AssignedRequest.OnDownloadProgress != null)
                    {
                        RequestEventHelper.EnqueueRequestEvent(new RequestEventInfo(this.AssignedRequest,
                                                                                    RequestEvents.DownloadProgress,
                                                                                    downloaded,
                                                                                    this.response.ExpectedContentLength));
                    }

                    break;

                case HTTP2FrameTypes.WINDOW_UPDATE:
                    HTTP2WindowUpdateFrame windowUpdateFrame = HTTP2FrameHelper.ReadWindowUpdateFrame(frame);

                    if (HTTPManager.Logger.Level == Logger.Loglevels.All)
                    {
                        HTTPManager.Logger.Information("HTTP2Stream", string.Format("[{0}] Received Window Update: {1:N0}, new remoteWindow: {2:N0}, initial remote window: {3:N0}, total data sent: {4:N0}", this.Id, windowUpdateFrame.WindowSizeIncrement, this.remoteWindow + windowUpdateFrame.WindowSizeIncrement, this.settings.RemoteSettings[HTTP2Settings.INITIAL_WINDOW_SIZE], this.sentData));
                    }

                    this.remoteWindow += windowUpdateFrame.WindowSizeIncrement;
                    break;

                case HTTP2FrameTypes.RST_STREAM:
                    // https://httpwg.org/specs/rfc7540.html#RST_STREAM

                    var rstStreamFrame = HTTP2FrameHelper.ReadRST_StreamFrame(frame);

                    HTTPManager.Logger.Error("HTTP2Stream", string.Format("[{0}] RST Stream frame ({1}) received in state {2}!", this.Id, rstStreamFrame, this.State));

                    Abort(string.Format("RST_STREAM frame received! Error code: {0}({1})", rstStreamFrame.Error.ToString(), rstStreamFrame.ErrorCode));
                    break;

                default:
                    HTTPManager.Logger.Warning("HTTP2Stream", string.Format("[{0}] Unexpected frame ({1}) in state {2}!", this.Id, frame, this.State));
                    break;
                }

                if (!frame.DontUseMemPool)
                {
                    BufferPool.Release(frame.Payload);
                }
            }

            if (windowUpdate > 0)
            {
                if (HTTPManager.Logger.Level <= Logger.Loglevels.All)
                {
                    HTTPManager.Logger.Information("HTTP2Stream", string.Format("[{0}] Sending window update: {1:N0}, current window: {2:N0}, initial window size: {3:N0}", this.Id, windowUpdate, this.localWindow, this.settings.MySettings[HTTP2Settings.INITIAL_WINDOW_SIZE]));
                }

                this.localWindow += windowUpdate;

                outgoingFrames.Add(HTTP2FrameHelper.CreateWindowUpdateFrame(this.Id, windowUpdate));
            }
        }
        public void RunHandler()
        {
            HTTPManager.Logger.Information("HTTP2Handler", "Processing thread up and running!");

            Thread.CurrentThread.Name = "HTTP2 Process";

            PlatformSupport.Threading.ThreadedRunner.RunLongLiving(ReadThread);

            try
            {
                bool atLeastOneStreamHasAFrameToSend = true;

                this.HPACKEncoder = new HPACKEncoder(this.settings);

                // https://httpwg.org/specs/rfc7540.html#InitialWindowSize
                // The connection flow-control window is also 65,535 octets.
                this.remoteWindow = this.settings.RemoteSettings[HTTP2Settings.INITIAL_WINDOW_SIZE];

                // we want to pack as many data as we can in one tcp segment, but setting the buffer's size too high
                //  we might keep data too long and send them in bursts instead of in a steady stream.
                // Keeping it too low might result in a full tcp segment and one with very low payload
                // Is it possible that one full tcp segment sized buffer would be the best, or multiple of it.
                // It would keep the network busy without any fragments. The ethernet layer has a maximum of 1500 bytes,
                // but there's two layers of 20 byte headers each, so as a theoretical maximum it's 1500-20-20 bytes.
                // On the other hand, if the buffer is small (1-2), that means that for larger data, we have to do a lot
                // of system calls, in that case a larger buffer might be better. Still, if we are not cpu bound,
                // a well saturated network might serve us better.
                using (WriteOnlyBufferedStream bufferedStream = new WriteOnlyBufferedStream(this.conn.connector.Stream, 1024 * 1024 /*1500 - 20 - 20*/))
                {
                    // The client connection preface starts with a sequence of 24 octets
                    bufferedStream.Write(MAGIC, 0, MAGIC.Length);

                    // This sequence MUST be followed by a SETTINGS frame (Section 6.5), which MAY be empty.
                    // The client sends the client connection preface immediately upon receipt of a
                    // 101 (Switching Protocols) response (indicating a successful upgrade)
                    // or as the first application data octets of a TLS connection

                    // Set streams' initial window size to its maximum.
                    this.settings.InitiatedMySettings[HTTP2Settings.INITIAL_WINDOW_SIZE]    = HTTPManager.HTTP2Settings.InitialStreamWindowSize;
                    this.settings.InitiatedMySettings[HTTP2Settings.MAX_CONCURRENT_STREAMS] = HTTPManager.HTTP2Settings.MaxConcurrentStreams;
                    this.settings.SendChanges(this.outgoingFrames);

                    // The default window size for the whole connection is 65535 bytes,
                    // but we want to set it to the maximum possible value.
                    Int64 diff = HTTPManager.HTTP2Settings.InitialConnectionWindowSize - 65535;
                    if (diff > 0)
                    {
                        this.outgoingFrames.Add(HTTP2FrameHelper.CreateWindowUpdateFrame(0, (UInt32)diff));
                    }

                    this.pingFrequency = HTTPManager.HTTP2Settings.PingFrequency;

                    while (this.isRunning)
                    {
                        if (!atLeastOneStreamHasAFrameToSend)
                        {
                            // buffered stream will call flush automatically if its internal buffer is full.
                            // But we have to make it sure that we flush remaining data before we go to sleep.
                            bufferedStream.Flush();

                            // Wait until we have to send the next ping, OR a new frame is received on the read thread.
                            //   Sent      Now  Sent+frequency
                            //-----|--------|----|------------
                            int wait = (int)((this.lastPingSent + this.pingFrequency) - DateTime.UtcNow).TotalMilliseconds;

                            wait = (int)Math.Min(wait, this.MaxGoAwayWaitTime.TotalMilliseconds);

                            if (wait >= 1)
                            {
                                if (HTTPManager.Logger.Level <= Logger.Loglevels.All)
                                {
                                    HTTPManager.Logger.Information("HTTP2Handler", string.Format("Sleeping for {0:N0}ms", wait));
                                }
                                this.newFrameSignal.WaitOne(wait);
                            }
                        }

                        DateTime now = DateTime.UtcNow;

                        if (now - this.lastPingSent >= this.pingFrequency)
                        {
                            this.lastPingSent = now;

                            var frame = HTTP2FrameHelper.CreatePingFrame(HTTP2PingFlags.None);
                            BufferHelper.SetLong(frame.Payload, 0, now.Ticks);

                            this.outgoingFrames.Add(frame);
                        }

                        // Process received frames
                        HTTP2FrameHeaderAndPayload header;
                        while (this.newFrames.TryDequeue(out header))
                        {
                            if (header.StreamId > 0)
                            {
                                HTTP2Stream http2Stream = FindStreamById(header.StreamId);

                                // Add frame to the stream, so it can process it when its Process function is called
                                if (http2Stream != null)
                                {
                                    http2Stream.AddFrame(header, this.outgoingFrames);
                                }
                                else
                                {
                                    // Error? It's possible that we closed and removed the stream while the server was in the middle of sending frames
                                    //HTTPManager.Logger.Warning("HTTP2Handler", string.Format("No stream found for id: {0}! Can't deliver frame: {1}", header.StreamId, header));
                                }
                            }
                            else
                            {
                                switch (header.Type)
                                {
                                case HTTP2FrameTypes.SETTINGS:
                                    this.settings.Process(header, this.outgoingFrames);
                                    break;

                                case HTTP2FrameTypes.PING:
                                    var pingFrame = HTTP2FrameHelper.ReadPingFrame(header);

                                    // if it wasn't an ack for our ping, we have to send one
                                    if ((pingFrame.Flags & HTTP2PingFlags.ACK) == 0)
                                    {
                                        var frame = HTTP2FrameHelper.CreatePingFrame(HTTP2PingFlags.ACK);
                                        Array.Copy(pingFrame.OpaqueData, 0, frame.Payload, 0, pingFrame.OpaqueDataLength);

                                        this.outgoingFrames.Add(frame);
                                    }
                                    break;

                                case HTTP2FrameTypes.WINDOW_UPDATE:
                                    var windowUpdateFrame = HTTP2FrameHelper.ReadWindowUpdateFrame(header);
                                    this.remoteWindow += windowUpdateFrame.WindowSizeIncrement;
                                    break;

                                case HTTP2FrameTypes.GOAWAY:
                                    // parse the frame, so we can print out detailed information
                                    HTTP2GoAwayFrame goAwayFrame = HTTP2FrameHelper.ReadGoAwayFrame(header);

                                    HTTPManager.Logger.Information("HTTP2Handler", "Received GOAWAY frame: " + goAwayFrame.ToString());

                                    string msg = string.Format("Server closing the connection! Error code: {0} ({1})", goAwayFrame.Error, goAwayFrame.ErrorCode);
                                    for (int i = 0; i < this.clientInitiatedStreams.Count; ++i)
                                    {
                                        this.clientInitiatedStreams[i].Abort(msg);
                                    }

                                    // set the running flag to false, so the thread can exit
                                    this.isRunning = false;

                                    this.conn.State = HTTPConnectionStates.Closed;
                                    break;

                                case HTTP2FrameTypes.ALT_SVC:
                                    //HTTP2AltSVCFrame altSvcFrame = HTTP2FrameHelper.ReadAltSvcFrame(header);

                                    // Implement
                                    //HTTPManager.EnqueuePluginEvent(new PluginEventInfo(PluginEvents.AltSvcHeader, new AltSvcEventInfo(altSvcFrame.Origin, ))
                                    break;
                                }
                            }
                        }

                        UInt32 maxConcurrentStreams = Math.Min(HTTPManager.HTTP2Settings.MaxConcurrentStreams, this.settings.RemoteSettings[HTTP2Settings.MAX_CONCURRENT_STREAMS]);

                        // pre-test stream count to lock only when truly needed.
                        if (this.clientInitiatedStreams.Count < maxConcurrentStreams && this.isRunning)
                        {
                            // grab requests from queue
                            HTTPRequest request;
                            while (this.clientInitiatedStreams.Count < maxConcurrentStreams && this.requestQueue.TryDequeue(out request))
                            {
                                // create a new stream
                                var newStream = new HTTP2Stream((UInt32)Interlocked.Add(ref LastStreamId, 2), this.settings, this.HPACKEncoder);

                                // process the request
                                newStream.Assign(request);

                                this.clientInitiatedStreams.Add(newStream);
                            }
                        }

                        // send any settings changes
                        this.settings.SendChanges(this.outgoingFrames);

                        atLeastOneStreamHasAFrameToSend = false;

                        // process other streams
                        // Room for improvement Streams should be processed by their priority!
                        for (int i = 0; i < this.clientInitiatedStreams.Count; ++i)
                        {
                            var stream = this.clientInitiatedStreams[i];
                            stream.Process(this.outgoingFrames);

                            // remove closed, empty streams (not enough to check the closed flag, a closed stream still can contain frames to send)
                            if (stream.State == HTTP2StreamStates.Closed && !stream.HasFrameToSend)
                            {
                                this.clientInitiatedStreams.RemoveAt(i--);
                                stream.Removed();
                            }

                            atLeastOneStreamHasAFrameToSend |= stream.HasFrameToSend;

                            this.lastInteraction = DateTime.UtcNow;
                        }

                        // If we encounter a data frame that too large for the current remote window, we have to stop
                        // sending all data frames as we could send smaller data frames before the large ones.
                        // Room for improvement: An improvement would be here to stop data frame sending per-stream.
                        bool haltDataSending = false;

                        if (this.ShutdownType == ShutdownTypes.Running && now - this.lastInteraction >= HTTPManager.HTTP2Settings.MaxIdleTime)
                        {
                            this.lastInteraction = DateTime.UtcNow;
                            HTTPManager.Logger.Information("HTTP2Handler", "Reached idle time, sending GoAway frame!");
                            this.outgoingFrames.Add(HTTP2FrameHelper.CreateGoAwayFrame(0, HTTP2ErrorCodes.NO_ERROR));
                            this.goAwaySentAt = DateTime.UtcNow;
                        }

                        // https://httpwg.org/specs/rfc7540.html#GOAWAY
                        // Endpoints SHOULD always send a GOAWAY frame before closing a connection so that the remote peer can know whether a stream has been partially processed or not.
                        if (this.ShutdownType == ShutdownTypes.Gentle)
                        {
                            HTTPManager.Logger.Information("HTTP2Handler", "Connection abort requested, sending GoAway frame!");

                            this.outgoingFrames.Clear();
                            this.outgoingFrames.Add(HTTP2FrameHelper.CreateGoAwayFrame(0, HTTP2ErrorCodes.NO_ERROR));
                            this.goAwaySentAt = DateTime.UtcNow;
                        }

                        if (this.isRunning && now - goAwaySentAt >= this.MaxGoAwayWaitTime)
                        {
                            HTTPManager.Logger.Information("HTTP2Handler", "No GoAway frame received back. Really quitting now!");
                            this.isRunning = false;
                            conn.State     = HTTPConnectionStates.Closed;
                        }

                        uint streamWindowUpdates = 0;

                        // Go through all the collected frames and send them.
                        for (int i = 0; i < this.outgoingFrames.Count; ++i)
                        {
                            var frame = this.outgoingFrames[i];

                            if (HTTPManager.Logger.Level <= Logger.Loglevels.All && frame.Type != HTTP2FrameTypes.DATA /*&& frame.Type != HTTP2FrameTypes.PING*/)
                            {
                                HTTPManager.Logger.Information("HTTP2Handler", "Sending frame: " + frame.ToString());
                            }

                            // post process frames
                            switch (frame.Type)
                            {
                            case HTTP2FrameTypes.DATA:
                                if (haltDataSending)
                                {
                                    continue;
                                }

                                // if the tracked remoteWindow is smaller than the frame's payload, we stop sending
                                // data frames until we receive window-update frames
                                if (frame.PayloadLength > this.remoteWindow)
                                {
                                    haltDataSending = true;
                                    HTTPManager.Logger.Warning("HTTP2Handler", string.Format("Data sending halted for this round. Remote Window: {0:N0}, frame: {1}", this.remoteWindow, frame.ToString()));
                                    continue;
                                }

                                break;

                            case HTTP2FrameTypes.WINDOW_UPDATE:
                                if (frame.StreamId > 0)
                                {
                                    streamWindowUpdates += BufferHelper.ReadUInt31(frame.Payload, 0);
                                }
                                break;
                            }

                            this.outgoingFrames.RemoveAt(i--);

                            using (var buffer = HTTP2FrameHelper.HeaderAsBinary(frame))
                                bufferedStream.Write(buffer.Data, 0, buffer.Length);

                            if (frame.PayloadLength > 0)
                            {
                                bufferedStream.Write(frame.Payload, (int)frame.PayloadOffset, (int)frame.PayloadLength);

                                if (!frame.DontUseMemPool)
                                {
                                    BufferPool.Release(frame.Payload);
                                }
                            }

                            if (frame.Type == HTTP2FrameTypes.DATA)
                            {
                                this.remoteWindow -= frame.PayloadLength;
                            }
                        }

                        if (streamWindowUpdates > 0)
                        {
                            var frame = HTTP2FrameHelper.CreateWindowUpdateFrame(0, streamWindowUpdates);

                            if (HTTPManager.Logger.Level <= Logger.Loglevels.All)
                            {
                                HTTPManager.Logger.Information("HTTP2Handler", "Sending frame: " + frame.ToString());
                            }

                            using (var buffer = HTTP2FrameHelper.HeaderAsBinary(frame))
                                bufferedStream.Write(buffer.Data, 0, buffer.Length);

                            bufferedStream.Write(frame.Payload, (int)frame.PayloadOffset, (int)frame.PayloadLength);
                        }
                    } // while (this.isRunning)

                    bufferedStream.Flush();
                }
            }
            catch (Exception ex)
            {
                // Log out the exception if it's a non-expected one.
                if (this.ShutdownType == ShutdownTypes.Running && this.goAwaySentAt == DateTime.MaxValue)
                {
                    HTTPManager.Logger.Exception("HTTP2Handler", "Sender thread", ex);
                }
            }
            finally
            {
                // First thread closing notifies the ConnectionEventHelper
                if (Interlocked.Increment(ref this.threadExitCount) == 1)
                {
                    ConnectionEventHelper.EnqueueConnectionEvent(new ConnectionEventInfo(this.conn, HTTPConnectionStates.Closed));
                }

                HTTPManager.Logger.Information("HTTP2Handler", "Sender thread closing - cleaning up remaining request...");

                for (int i = 0; i < this.clientInitiatedStreams.Count; ++i)
                {
                    this.clientInitiatedStreams[i].Abort("Connection closed unexpectedly");
                }
                this.clientInitiatedStreams.Clear();

                HTTPRequest request = null;
                while (this.requestQueue.TryDequeue(out request))
                {
                    HTTPManager.Logger.Information("HTTP2Handler", string.Format("Request '{0}' IsCancellationRequested: {1}", request.CurrentUri.ToString(), request.IsCancellationRequested.ToString()));
                    if (request.IsCancellationRequested)
                    {
                        request.Response = null;
                        request.State    = HTTPRequestStates.Aborted;
                    }
                    else
                    {
                        RequestEventHelper.EnqueueRequestEvent(new RequestEventInfo(request, RequestEvents.Resend));
                    }
                }

                HTTPManager.Logger.Information("HTTP2Handler", "Sender thread closing");
            }

            try
            {
                // Works in the new runtime
                if (this.conn.connector.TopmostStream != null)
                {
                    using (this.conn.connector.TopmostStream) { }
                }

                // Works in the old runtime
                if (this.conn.connector.Stream != null)
                {
                    using (this.conn.connector.Stream) { }
                }
            }
            catch
            { }
        }
        private void ReadThread()
        {
            try
            {
                Thread.CurrentThread.Name = "HTTP2 Read";
                HTTPManager.Logger.Information("HTTP2Handler", "Reader thread up and running!");

                using (ReadOnlyBufferedStream bufferedStream = new ReadOnlyBufferedStream(this.conn.connector.Stream, 32 * 1024))
                {
                    while (this.isRunning)
                    {
                        // TODO:
                        //  1. Set the local window to a reasonable size
                        //  2. stop reading when the local window is about to be 0.
                        //  3.
                        HTTP2FrameHeaderAndPayload header = HTTP2FrameHelper.ReadHeader(bufferedStream);

                        if (HTTPManager.Logger.Level <= Logger.Loglevels.Information && header.Type != HTTP2FrameTypes.DATA /*&& header.Type != HTTP2FrameTypes.PING*/)
                        {
                            HTTPManager.Logger.Information("HTTP2Handler", "New frame received: " + header.ToString());
                        }

                        // Add the new frame to the queue. Processing it on the write thread gives us the advantage that
                        //  we don't have to deal with too much locking.
                        this.newFrames.Enqueue(header);

                        // ping write thread to process the new frame
                        this.newFrameSignal.Set();

                        switch (header.Type)
                        {
                        // Handle pongs on the read thread, so no additional latency is added to the rtt calculation.
                        case HTTP2FrameTypes.PING:
                            var pingFrame = HTTP2FrameHelper.ReadPingFrame(header);

                            if ((pingFrame.Flags & HTTP2PingFlags.ACK) != 0)
                            {
                                // it was an ack, payload must contain what we sent

                                var ticks = BufferHelper.ReadLong(pingFrame.OpaqueData, 0);

                                // the difference between the current time and the time when the ping message is sent
                                TimeSpan diff = TimeSpan.FromTicks(DateTime.UtcNow.Ticks - ticks);

                                // add it to the buffer
                                this.rtts.Add(diff.TotalMilliseconds);

                                // and calculate the new latency
                                this.Latency = CalculateLatency();

                                HTTPManager.Logger.Verbose("HTTP2Handler", string.Format("Latency: {0:F2}ms, RTT buffer: {1}", this.Latency, this.rtts.ToString()));
                            }
                            break;

                        case HTTP2FrameTypes.GOAWAY:
                            // Just exit from this thread. The processing thread will handle the frame too.
                            return;
                        }
                    }
                }
            }
            catch //(Exception ex)
            {
                //HTTPManager.Logger.Exception("HTTP2Handler", "", ex);

                this.isRunning = false;
                this.newFrameSignal.Set();
            }
            finally
            {
                // First thread closing notifies the ConnectionEventHelper
                if (Interlocked.Increment(ref this.threadExitCount) == 1)
                {
                    ConnectionEventHelper.EnqueueConnectionEvent(new ConnectionEventInfo(this.conn, HTTPConnectionStates.Closed));
                }

                HTTPManager.Logger.Information("HTTP2Handler", "Reader thread closing");
            }
        }