TUN-528: Move cloudflared into a separate repo

h2mux/activestreammap.go

@@ -0,0 +1,165 @@
+package h2mux
+
+import (
+	"sync"
+
+	"golang.org/x/net/http2"
+)
+
+// activeStreamMap is used to moderate access to active streams between the read and write
+// threads, and deny access to new peer streams while shutting down.
+type activeStreamMap struct {
+	sync.RWMutex
+	// streams tracks open streams.
+	streams map[uint32]*MuxedStream
+	// streamsEmpty is a chan that should be closed when no more streams are open.
+	streamsEmpty chan struct{}
+	// nextStreamID is the next ID to use on our side of the connection.
+	// This is odd for clients, even for servers.
+	nextStreamID uint32
+	// maxPeerStreamID is the ID of the most recent stream opened by the peer.
+	maxPeerStreamID uint32
+	// ignoreNewStreams is true when the connection is being shut down. New streams
+	// cannot be registered.
+	ignoreNewStreams bool
+}
+
+func newActiveStreamMap(useClientStreamNumbers bool) *activeStreamMap {
+	m := &activeStreamMap{
+		streams:      make(map[uint32]*MuxedStream),
+		streamsEmpty: make(chan struct{}),
+		nextStreamID: 1,
+	}
+	// Client initiated stream uses odd stream ID, server initiated stream uses even stream ID
+	if !useClientStreamNumbers {
+		m.nextStreamID = 2
+	}
+	return m
+}
+
+// Len returns the number of active streams.
+func (m *activeStreamMap) Len() int {
+	m.RLock()
+	defer m.RUnlock()
+	return len(m.streams)
+}
+
+func (m *activeStreamMap) Get(streamID uint32) (*MuxedStream, bool) {
+	m.RLock()
+	defer m.RUnlock()
+	stream, ok := m.streams[streamID]
+	return stream, ok
+}
+
+// Set returns true if the stream was assigned successfully. If a stream
+// already existed with that ID or we are shutting down, return false.
+func (m *activeStreamMap) Set(newStream *MuxedStream) bool {
+	m.Lock()
+	defer m.Unlock()
+	if _, ok := m.streams[newStream.streamID]; ok {
+		return false
+	}
+	if m.ignoreNewStreams {
+		return false
+	}
+	m.streams[newStream.streamID] = newStream
+	return true
+}
+
+// Delete stops tracking the stream. It should be called only after it is closed and resetted.
+func (m *activeStreamMap) Delete(streamID uint32) {
+	m.Lock()
+	defer m.Unlock()
+	delete(m.streams, streamID)
+	if len(m.streams) == 0 && m.streamsEmpty != nil {
+		close(m.streamsEmpty)
+		m.streamsEmpty = nil
+	}
+}
+
+// Shutdown blocks new streams from being created. It returns a channel that receives an event
+// once the last stream has closed, or nil if a shutdown is in progress.
+func (m *activeStreamMap) Shutdown() <-chan struct{} {
+	m.Lock()
+	defer m.Unlock()
+	if m.ignoreNewStreams {
+		// already shutting down
+		return nil
+	}
+	m.ignoreNewStreams = true
+	done := make(chan struct{})
+	if len(m.streams) == 0 {
+		// nothing to shut down
+		close(done)
+		return done
+	}
+	m.streamsEmpty = done
+	return done
+}
+
+// AcquireLocalID acquires a new stream ID for a stream you're opening.
+func (m *activeStreamMap) AcquireLocalID() uint32 {
+	m.Lock()
+	defer m.Unlock()
+	x := m.nextStreamID
+	m.nextStreamID += 2
+	return x
+}
+
+// ObservePeerID observes the ID of a stream opened by the peer. It returns true if we should accept
+// the new stream, or false to reject it. The ErrCode gives the reason why.
+func (m *activeStreamMap) AcquirePeerID(streamID uint32) (bool, http2.ErrCode) {
+	m.Lock()
+	defer m.Unlock()
+	switch {
+	case m.ignoreNewStreams:
+		return false, http2.ErrCodeStreamClosed
+	case streamID > m.maxPeerStreamID:
+		m.maxPeerStreamID = streamID
+		return true, http2.ErrCodeNo
+	default:
+		return false, http2.ErrCodeStreamClosed
+	}
+}
+
+// IsPeerStreamID is true if the stream ID belongs to the peer.
+func (m *activeStreamMap) IsPeerStreamID(streamID uint32) bool {
+	m.RLock()
+	defer m.RUnlock()
+	return (streamID % 2) != (m.nextStreamID % 2)
+}
+
+// IsLocalStreamID is true if it is a stream we have opened, even if it is now closed.
+func (m *activeStreamMap) IsLocalStreamID(streamID uint32) bool {
+	m.RLock()
+	defer m.RUnlock()
+	return (streamID%2) == (m.nextStreamID%2) && streamID < m.nextStreamID
+}
+
+// LastPeerStreamID returns the most recently opened peer stream ID.
+func (m *activeStreamMap) LastPeerStreamID() uint32 {
+	m.RLock()
+	defer m.RUnlock()
+	return m.maxPeerStreamID
+}
+
+// LastLocalStreamID returns the most recently opened local stream ID.
+func (m *activeStreamMap) LastLocalStreamID() uint32 {
+	m.RLock()
+	defer m.RUnlock()
+	if m.nextStreamID > 1 {
+		return m.nextStreamID - 2
+	}
+	return 0
+}
+
+// Abort closes every active stream and prevents new ones being created. This should be used to
+// return errors in pending read/writes when the underlying connection goes away.
+func (m *activeStreamMap) Abort() {
+	m.Lock()
+	defer m.Unlock()
+	for _, stream := range m.streams {
+		stream.Close()
+	}
+	m.ignoreNewStreams = true
+}

h2mux/booleanfuse.go

@@ -0,0 +1,50 @@
+package h2mux
+
+import "sync"
+
+// BooleanFuse is a data structure that can be set once to a particular value using Fuse(value).
+// Subsequent calls to Fuse() will have no effect.
+type BooleanFuse struct {
+	value int32
+	mu    sync.Mutex
+	cond  *sync.Cond
+}
+
+func NewBooleanFuse() *BooleanFuse {
+	f := &BooleanFuse{}
+	f.cond = sync.NewCond(&f.mu)
+	return f
+}
+
+// Value gets the value
+func (f *BooleanFuse) Value() bool {
+	// 0: unset
+	// 1: set true
+	// 2: set false
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	return f.value == 1
+}
+
+func (f *BooleanFuse) Fuse(result bool) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	newValue := int32(2)
+	if result {
+		newValue = 1
+	}
+	if f.value == 0 {
+		f.value = newValue
+		f.cond.Broadcast()
+	}
+}
+
+// Await blocks until Fuse has been called at least once.
+func (f *BooleanFuse) Await() bool {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	for f.value == 0 {
+		f.cond.Wait()
+	}
+	return f.value == 1
+}

h2mux/bytes_counter.go

@@ -0,0 +1,27 @@
+package h2mux
+
+import (
+	"sync/atomic"
+)
+
+type AtomicCounter struct {
+	count uint64
+}
+
+func NewAtomicCounter(initCount uint64) *AtomicCounter {
+	return &AtomicCounter{count: initCount}
+}
+
+func (c *AtomicCounter) IncrementBy(number uint64) {
+	atomic.AddUint64(&c.count, number)
+}
+
+// Count returns the current value of counter and reset it to 0
+func (c *AtomicCounter) Count() uint64 {
+	return atomic.SwapUint64(&c.count, 0)
+}
+
+// Value returns the current value of counter
+func (c *AtomicCounter) Value() uint64 {
+	return atomic.LoadUint64(&c.count)
+}

h2mux/bytes_counter_test.go

@@ -0,0 +1,23 @@
+package h2mux
+
+import (
+	"sync"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCounter(t *testing.T) {
+	var wg sync.WaitGroup
+	wg.Add(dataPoints)
+	c := AtomicCounter{}
+	for i := 0; i < dataPoints; i++ {
+		go func() {
+			defer wg.Done()
+			c.IncrementBy(uint64(1))
+		}()
+	}
+	wg.Wait()
+	assert.Equal(t, uint64(dataPoints), c.Count())
+	assert.Equal(t, uint64(0), c.Count())
+}

h2mux/error.go

@@ -0,0 +1,61 @@
+package h2mux
+
+import (
+	"fmt"
+
+	"golang.org/x/net/http2"
+)
+
+var (
+	ErrHandshakeTimeout               = MuxerHandshakeError{"1000 handshake timeout"}
+	ErrBadHandshakeNotSettings        = MuxerHandshakeError{"1001 unexpected response"}
+	ErrBadHandshakeUnexpectedAck      = MuxerHandshakeError{"1002 unexpected response"}
+	ErrBadHandshakeNoMagic            = MuxerHandshakeError{"1003 unexpected response"}
+	ErrBadHandshakeWrongMagic         = MuxerHandshakeError{"1004 connected to endpoint of wrong type"}
+	ErrBadHandshakeNotSettingsAck     = MuxerHandshakeError{"1005 unexpected response"}
+	ErrBadHandshakeUnexpectedSettings = MuxerHandshakeError{"1006 unexpected response"}
+
+	ErrUnexpectedFrameType = MuxerProtocolError{"2001 unexpected frame type", http2.ErrCodeProtocol}
+	ErrUnknownStream       = MuxerProtocolError{"2002 unknown stream", http2.ErrCodeProtocol}
+	ErrInvalidStream       = MuxerProtocolError{"2003 invalid stream", http2.ErrCodeProtocol}
+
+	ErrStreamHeadersSent = MuxerApplicationError{"3000 headers already sent"}
+	ErrConnectionClosed  = MuxerApplicationError{"3001 connection closed"}
+	ErrConnectionDropped = MuxerApplicationError{"3002 connection dropped"}
+
+	ErrClosedStream = MuxerStreamError{"4000 stream closed", http2.ErrCodeStreamClosed}
+)
+
+type MuxerHandshakeError struct {
+	cause string
+}
+
+func (e MuxerHandshakeError) Error() string {
+	return fmt.Sprintf("Handshake error: %s", e.cause)
+}
+
+type MuxerProtocolError struct {
+	cause  string
+	h2code http2.ErrCode
+}
+
+func (e MuxerProtocolError) Error() string {
+	return fmt.Sprintf("Protocol error: %s", e.cause)
+}
+
+type MuxerApplicationError struct {
+	cause string
+}
+
+func (e MuxerApplicationError) Error() string {
+	return fmt.Sprintf("Application error: %s", e.cause)
+}
+
+type MuxerStreamError struct {
+	cause  string
+	h2code http2.ErrCode
+}
+
+func (e MuxerStreamError) Error() string {
+	return fmt.Sprintf("Stream error: %s", e.cause)
+}

h2mux/h2_compressor_brotli.go

@@ -0,0 +1,21 @@
+// +build cgo
+
+package h2mux
+
+import (
+	"io"
+
+	"code.cfops.it/go/brotli"
+)
+
+func CompressionIsSupported() bool {
+	return true
+}
+
+func newDecompressor(src io.Reader) *brotli.Reader {
+	return brotli.NewReader(src)
+}
+
+func newCompressor(dst io.Writer, quality, lgwin int) *brotli.Writer {
+	return brotli.NewWriter(dst, brotli.WriterOptions{Quality: quality, LGWin: lgwin})
+}

h2mux/h2_compressor_none.go

@@ -0,0 +1,19 @@
+// +build !cgo
+
+package h2mux
+
+import (
+	"io"
+)
+
+func CompressionIsSupported() bool {
+	return false
+}
+
+func newDecompressor(src io.Reader) decompressor {
+	return nil
+}
+
+func newCompressor(dst io.Writer, quality, lgwin int) compressor {
+	return nil
+}

h2mux/h2_dictionaries.go

@@ -0,0 +1,593 @@
+package h2mux
+
+import (
+	"bytes"
+	"io"
+	"strings"
+	"sync"
+
+	"golang.org/x/net/http2"
+)
+
+/* This is an implementation of https://github.com/vkrasnov/h2-compression-dictionaries
+but modified for tunnels in a few key ways:
+Since tunnels is a server-to-server service, some aspects of the spec would cause
+unnessasary head-of-line blocking on the CPU and on the network, hence this implementation
+allows for parallel compression on the "client", and buffering on the "server" to solve
+this problem. */
+
+// Assign temporary values
+const SettingCompression http2.SettingID = 0xff20
+
+const (
+	FrameSetCompressionContext http2.FrameType = 0xf0
+	FrameUseDictionary         http2.FrameType = 0xf1
+	FrameSetDictionary         http2.FrameType = 0xf2
+)
+
+const (
+	FlagSetDictionaryAppend http2.Flags = 0x1
+	FlagSetDictionaryOffset http2.Flags = 0x2
+)
+
+const compressionVersion = uint8(1)
+const compressionFormat = uint8(2)
+
+type CompressionSetting uint
+
+const (
+	CompressionNone CompressionSetting = iota
+	CompressionLow
+	CompressionMedium
+	CompressionMax
+)
+
+type CompressionPreset struct {
+	nDicts, dictSize, quality uint8
+}
+
+type compressor interface {
+	Write([]byte) (int, error)
+	Flush() error
+	SetDictionary([]byte)
+	Close() error
+}
+
+type decompressor interface {
+	Read([]byte) (int, error)
+	SetDictionary([]byte)
+	Close() error
+}
+
+var compressionPresets = map[CompressionSetting]CompressionPreset{
+	CompressionNone:   {0, 0, 0},
+	CompressionLow:    {32, 17, 5},
+	CompressionMedium: {64, 18, 6},
+	CompressionMax:    {255, 19, 9},
+}
+
+func compressionSettingVal(version, fmt, sz, nd uint8) uint32 {
+	// Currently the compression settings are inlcude:
+	// * version: only 1 is supported
+	// * fmt: only 2 for brotli is supported
+	// * sz: log2 of the maximal allowed dictionary size
+	// * nd: max allowed number of dictionaries
+	return uint32(version)<<24 + uint32(fmt)<<16 + uint32(sz)<<8 + uint32(nd)
+}
+
+func parseCompressionSettingVal(setting uint32) (version, fmt, sz, nd uint8) {
+	version = uint8(setting >> 24)
+	fmt = uint8(setting >> 16)
+	sz = uint8(setting >> 8)
+	nd = uint8(setting)
+	return
+}
+
+func (c CompressionSetting) toH2Setting() uint32 {
+	p, ok := compressionPresets[c]
+	if !ok {
+		return 0
+	}
+	return compressionSettingVal(compressionVersion, compressionFormat, p.dictSize, p.nDicts)
+}
+
+func (c CompressionSetting) getPreset() CompressionPreset {
+	return compressionPresets[c]
+}
+
+type dictUpdate struct {
+	reader     *h2DictionaryReader
+	dictionary *h2ReadDictionary
+	buff       []byte
+	isReady    bool
+	isUse      bool
+	s          setDictRequest
+}
+
+type h2ReadDictionary struct {
+	dictionary []byte
+	queue      []*dictUpdate
+	maxSize    int
+}
+
+type h2ReadDictionaries struct {
+	d       []h2ReadDictionary
+	maxSize int
+}
+
+type h2DictionaryReader struct {
+	*SharedBuffer                // Propagate the decompressed output into the original buffer
+	decompBuffer   *bytes.Buffer // Intermediate buffer for the brotli compressor
+	dictionary     []byte        // The content of the dictionary being used by this reader
+	internalBuffer []byte
+	s, e           int           // Start and end of the buffer
+	decomp         decompressor  // The brotli compressor
+	isClosed       bool          // Indicates that Close was called for this reader
+	queue          []*dictUpdate // List of dictionaries to update, when the data is available
+}
+
+type h2WriteDictionary []byte
+
+type setDictRequest struct {
+	streamID         uint32
+	dictID           uint8
+	dictSZ           uint64
+	truncate, offset uint64
+	P, E, D          bool
+}
+
+type useDictRequest struct {
+	dictID   uint8
+	streamID uint32
+	setDict  []setDictRequest
+}
+
+type h2WriteDictionaries struct {
+	dictLock        sync.Mutex
+	dictChan        chan useDictRequest
+	dictionaries    []h2WriteDictionary
+	nextAvail       int              // next unused dictionary slot
+	maxAvail        int              // max ID, defined by SETTINGS
+	maxSize         int              // max size, defined by SETTINGS
+	typeToDict      map[string]uint8 // map from content type to dictionary that encodes it
+	pathToDict      map[string]uint8 // map from path to dictionary that encodes it
+	quality         int
+	window          int
+	compIn, compOut *AtomicCounter
+}
+
+type h2DictWriter struct {
+	*bytes.Buffer
+	comp       compressor
+	dicts      *h2WriteDictionaries
+	writerLock sync.Mutex
+
+	streamID    uint32
+	path        string
+	contentType string
+}
+
+type h2Dictionaries struct {
+	write *h2WriteDictionaries
+	read  *h2ReadDictionaries
+}
+
+func (o *dictUpdate) update(buff []byte) {
+	o.buff = make([]byte, len(buff))
+	copy(o.buff, buff)
+	o.isReady = true
+}
+
+func (d *h2ReadDictionary) update() {
+	for len(d.queue) > 0 {
+		o := d.queue[0]
+		if !o.isReady {
+			break
+		}
+		if o.isUse {
+			reader := o.reader
+			reader.dictionary = make([]byte, len(d.dictionary))
+			copy(reader.dictionary, d.dictionary)
+			reader.decomp = newDecompressor(reader.decompBuffer)
+			if len(reader.dictionary) > 0 {
+				reader.decomp.SetDictionary(reader.dictionary)
+			}
+			reader.Write([]byte{})
+		} else {
+			d.dictionary = adjustDictionary(d.dictionary, o.buff, o.s, d.maxSize)
+		}
+		d.queue = d.queue[1:]
+	}
+}
+
+func newH2ReadDictionaries(nd, sz uint8) h2ReadDictionaries {
+	d := make([]h2ReadDictionary, int(nd))
+	for i := range d {
+		d[i].maxSize = 1 << uint(sz)
+	}
+	return h2ReadDictionaries{d: d, maxSize: 1 << uint(sz)}
+}
+
+func (dicts *h2ReadDictionaries) getDictByID(dictID uint8) (*h2ReadDictionary, error) {
+	if int(dictID) > len(dicts.d) {
+		return nil, MuxerStreamError{"dictID too big", http2.ErrCodeProtocol}
+	}
+
+	return &dicts.d[dictID], nil
+}
+
+func (dicts *h2ReadDictionaries) newReader(b *SharedBuffer, dictID uint8) *h2DictionaryReader {
+	if int(dictID) > len(dicts.d) {
+		return nil
+	}
+
+	dictionary := &dicts.d[dictID]
+	reader := &h2DictionaryReader{SharedBuffer: b, decompBuffer: &bytes.Buffer{}, internalBuffer: make([]byte, dicts.maxSize)}
+
+	if len(dictionary.queue) == 0 {
+		reader.dictionary = make([]byte, len(dictionary.dictionary))
+		copy(reader.dictionary, dictionary.dictionary)
+		reader.decomp = newDecompressor(reader.decompBuffer)
+		if len(reader.dictionary) > 0 {
+			reader.decomp.SetDictionary(reader.dictionary)
+		}
+	} else {
+		dictionary.queue = append(dictionary.queue, &dictUpdate{isUse: true, isReady: true, reader: reader})
+	}
+	return reader
+}
+
+func (r *h2DictionaryReader) updateWaitingDictionaries() {
+	// Update all the waiting dictionaries
+	for _, o := range r.queue {
+		if o.isReady {
+			continue
+		}
+		if r.isClosed || uint64(r.e) >= o.s.dictSZ {
+			o.update(r.internalBuffer[:r.e])
+			if o == o.dictionary.queue[0] {
+				defer o.dictionary.update()
+			}
+		}
+	}
+}
+
+// Write actually happens when reading from network, this is therefore the stage where we decompress the buffer
+func (r *h2DictionaryReader) Write(p []byte) (n int, err error) {
+	// Every write goes into brotli buffer first
+	n, err = r.decompBuffer.Write(p)
+	if err != nil {
+		return
+	}
+
+	if r.decomp == nil {
+		return
+	}
+
+	for {
+		m, err := r.decomp.Read(r.internalBuffer[r.e:])
+		if err != nil && err != io.EOF {
+			r.SharedBuffer.Close()
+			r.decomp.Close()
+			return n, err
+		}
+
+		r.SharedBuffer.Write(r.internalBuffer[r.e : r.e+m])
+		r.e += m
+
+		if m == 0 {
+			break
+		}
+
+		if r.e == len(r.internalBuffer) {
+			r.updateWaitingDictionaries()
+			r.e = 0
+		}
+	}
+
+	r.updateWaitingDictionaries()
+
+	if r.isClosed {
+		r.SharedBuffer.Close()
+		r.decomp.Close()
+	}
+
+	return
+}
+
+func (r *h2DictionaryReader) Close() error {
+	if r.isClosed {
+		return nil
+	}
+	r.isClosed = true
+	r.Write([]byte{})
+	return nil
+}
+
+var compressibleTypes = map[string]bool{
+	"application/atom+xml":                true,
+	"application/javascript":              true,
+	"application/json":                    true,
+	"application/ld+json":                 true,
+	"application/manifest+json":           true,
+	"application/rss+xml":                 true,
+	"application/vnd.geo+json":            true,
+	"application/vnd.ms-fontobject":       true,
+	"application/x-font-ttf":              true,
+	"application/x-yaml":                  true,
+	"application/x-web-app-manifest+json": true,
+	"application/xhtml+xml":               true,
+	"application/xml":                     true,
+	"font/opentype":                       true,
+	"image/bmp":                           true,
+	"image/svg+xml":                       true,
+	"image/x-icon":                        true,
+	"text/cache-manifest":                 true,
+	"text/css":                            true,
+	"text/html":                           true,
+	"text/plain":                          true,
+	"text/vcard":                          true,
+	"text/vnd.rim.location.xloc":          true,
+	"text/vtt":                            true,
+	"text/x-component":                    true,
+	"text/x-cross-domain-policy":          true,
+	"text/x-yaml":                         true,
+}
+
+func getContentType(headers []Header) string {
+	for _, h := range headers {
+		if strings.ToLower(h.Name) == "content-type" {
+			val := strings.ToLower(h.Value)
+			sep := strings.IndexRune(val, ';')
+			if sep != -1 {
+				return val[:sep]
+			}
+			return val
+		}
+	}
+
+	return ""
+}
+
+func newH2WriteDictionaries(nd, sz, quality uint8, compIn, compOut *AtomicCounter) (*h2WriteDictionaries, chan useDictRequest) {
+	useDictChan := make(chan useDictRequest)
+	return &h2WriteDictionaries{
+		dictionaries: make([]h2WriteDictionary, nd),
+		nextAvail:    0,
+		maxAvail:     int(nd),
+		maxSize:      1 << uint(sz),
+		dictChan:     useDictChan,
+		typeToDict:   make(map[string]uint8),
+		pathToDict:   make(map[string]uint8),
+		quality:      int(quality),
+		window:       1 << uint(sz+1),
+		compIn:       compIn,
+		compOut:      compOut,
+	}, useDictChan
+}
+
+func adjustDictionary(currentDictionary, newData []byte, set setDictRequest, maxSize int) []byte {
+	currentDictionary = append(currentDictionary, newData[:set.dictSZ]...)
+
+	if len(currentDictionary) > maxSize {
+		currentDictionary = currentDictionary[len(currentDictionary)-maxSize:]
+	}
+
+	return currentDictionary
+}
+
+func (h2d *h2WriteDictionaries) getNextDictID() (dictID uint8, ok bool) {
+	if h2d.nextAvail < h2d.maxAvail {
+		dictID, ok = uint8(h2d.nextAvail), true
+		h2d.nextAvail++
+		return
+	}
+
+	return 0, false
+}
+
+func (h2d *h2WriteDictionaries) getGenericDictID() (dictID uint8, ok bool) {
+	if h2d.maxAvail == 0 {
+		return 0, false
+	}
+	return uint8(h2d.maxAvail - 1), true
+}
+
+func (h2d *h2WriteDictionaries) getDictWriter(s *MuxedStream, headers []Header) *h2DictWriter {
+	w := s.writeBuffer
+
+	if w == nil {
+		return nil
+	}
+
+	if s.method != "GET" && s.method != "POST" {
+		return nil
+	}
+
+	s.contentType = getContentType(headers)
+	if _, ok := compressibleTypes[s.contentType]; !ok && !strings.HasPrefix(s.contentType, "text") {
+		return nil
+	}
+
+	return &h2DictWriter{
+		Buffer:      w.(*bytes.Buffer),
+		path:        s.path,
+		contentType: s.contentType,
+		streamID:    s.streamID,
+		dicts:       h2d,
+	}
+}
+
+func assignDictToStream(s *MuxedStream, p []byte) bool {
+
+	// On first write to stream:
+	// * assign the right dictionary
+	// * update relevant dictionaries
+	// * send the required USE_DICT and SET_DICT frames
+
+	h2d := s.dictionaries.write
+	if h2d == nil {
+		return false
+	}
+
+	w, ok := s.writeBuffer.(*h2DictWriter)
+	if !ok || w.comp != nil {
+		return false
+	}
+
+	h2d.dictLock.Lock()
+
+	if w.comp != nil {
+		// Check again with lock, in therory the inteface allows for unordered writes
+		h2d.dictLock.Unlock()
+		return false
+	}
+
+	// The logic of dictionary generation is below
+
+	// Is there a dictionary for the exact path or content-type?
+	var useID uint8
+	pathID, pathFound := h2d.pathToDict[w.path]
+	typeID, typeFound := h2d.typeToDict[w.contentType]
+
+	if pathFound {
+		// Use dictionary for path as top priority
+		useID = pathID
+		if !typeFound { // Shouldn't really happen, unless type changes between requests
+			typeID, typeFound = h2d.getNextDictID()
+			if typeFound {
+				h2d.typeToDict[w.contentType] = typeID
+			}
+		}
+	} else if typeFound {
+		// Use dictionary for same content type as second priority
+		useID = typeID
+		pathID, pathFound = h2d.getNextDictID()
+		if pathFound { // If a slot is available, generate new dictionary for path
+			h2d.pathToDict[w.path] = pathID
+		}
+	} else {
+		// Use the overflow dictionary as last resort
+		// If slots are availabe generate new dictioanries for path and content-type
+		useID, _ = h2d.getGenericDictID()
+		pathID, pathFound = h2d.getNextDictID()
+		if pathFound {
+			h2d.pathToDict[w.path] = pathID
+		}
+		typeID, typeFound = h2d.getNextDictID()
+		if typeFound {
+			h2d.typeToDict[w.contentType] = typeID
+		}
+	}
+
+	useLen := h2d.maxSize
+	if len(p) < useLen {
+		useLen = len(p)
+	}
+
+	// Update all the dictionaries using the new data
+	setDicts := make([]setDictRequest, 0, 3)
+	setDict := setDictRequest{
+		streamID: w.streamID,
+		dictID:   useID,
+		dictSZ:   uint64(useLen),
+	}
+	setDicts = append(setDicts, setDict)
+	if pathID != useID {
+		setDict.dictID = pathID
+		setDicts = append(setDicts, setDict)
+	}
+	if typeID != useID {
+		setDict.dictID = typeID
+		setDicts = append(setDicts, setDict)
+	}
+
+	h2d.dictChan <- useDictRequest{streamID: w.streamID, dictID: uint8(useID), setDict: setDicts}
+
+	dict := h2d.dictionaries[useID]
+
+	// Brolti requires the dictionary to be immutable
+	copyDict := make([]byte, len(dict))
+	copy(copyDict, dict)
+
+	for _, set := range setDicts {
+		h2d.dictionaries[set.dictID] = adjustDictionary(h2d.dictionaries[set.dictID], p, set, h2d.maxSize)
+	}
+
+	w.comp = newCompressor(w.Buffer, h2d.quality, h2d.window)
+
+	s.writeLock.Lock()
+	h2d.dictLock.Unlock()
+
+	if len(copyDict) > 0 {
+		w.comp.SetDictionary(copyDict)
+	}
+
+	return true
+}
+
+func (w *h2DictWriter) Write(p []byte) (n int, err error) {
+	bufLen := w.Buffer.Len()
+	if w.comp != nil {
+		n, err = w.comp.Write(p)
+		if err != nil {
+			return
+		}
+		err = w.comp.Flush()
+		w.dicts.compIn.IncrementBy(uint64(n))
+		w.dicts.compOut.IncrementBy(uint64(w.Buffer.Len() - bufLen))
+		return
+	}
+	return w.Buffer.Write(p)
+}
+
+func (w *h2DictWriter) Close() error {
+	return w.comp.Close()
+}
+
+// From http2/hpack
+func http2ReadVarInt(n byte, p []byte) (remain []byte, v uint64, err error) {
+	if n < 1 || n > 8 {
+		panic("bad n")
+	}
+	if len(p) == 0 {
+		return nil, 0, MuxerStreamError{"unexpected EOF", http2.ErrCodeProtocol}
+	}
+	v = uint64(p[0])
+	if n < 8 {
+		v &= (1 << uint64(n)) - 1
+	}
+	if v < (1<<uint64(n))-1 {
+		return p[1:], v, nil
+	}
+
+	origP := p
+	p = p[1:]
+	var m uint64
+	for len(p) > 0 {
+		b := p[0]
+		p = p[1:]
+		v += uint64(b&127) << m
+		if b&128 == 0 {
+			return p, v, nil
+		}
+		m += 7
+		if m >= 63 {
+			return origP, 0, MuxerStreamError{"invalid integer", http2.ErrCodeProtocol}
+		}
+	}
+	return nil, 0, MuxerStreamError{"unexpected EOF", http2.ErrCodeProtocol}
+}
+
+func appendVarInt(dst []byte, n byte, i uint64) []byte {
+	k := uint64((1 << n) - 1)
+	if i < k {
+		return append(dst, byte(i))
+	}
+	dst = append(dst, byte(k))
+	i -= k
+	for ; i >= 128; i >>= 7 {
+		dst = append(dst, byte(0x80|(i&0x7f)))
+	}
+	return append(dst, byte(i))
+}

h2mux/h2mux.go

@@ -0,0 +1,415 @@
+package h2mux
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"strings"
+	"sync"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/hpack"
+	"golang.org/x/sync/errgroup"
+)
+
+const (
+	defaultFrameSize  uint32        = 1 << 14 // Minimum frame size in http2 spec
+	defaultWindowSize uint32        = 65535
+	maxWindowSize     uint32        = (1 << 31) - 1 // 2^31-1 = 2147483647, max window size specified in http2 spec
+	defaultTimeout    time.Duration = 5 * time.Second
+	defaultRetries    uint64        = 5
+
+	SettingMuxerMagic http2.SettingID = 0x42db
+	MuxerMagicOrigin  uint32          = 0xa2e43c8b
+	MuxerMagicEdge    uint32          = 0x1088ebf9
+)
+
+type MuxedStreamHandler interface {
+	ServeStream(*MuxedStream) error
+}
+
+type MuxedStreamFunc func(stream *MuxedStream) error
+
+func (f MuxedStreamFunc) ServeStream(stream *MuxedStream) error {
+	return f(stream)
+}
+
+type MuxerConfig struct {
+	Timeout  time.Duration
+	Handler  MuxedStreamHandler
+	IsClient bool
+	// Name is used to identify this muxer instance when logging.
+	Name string
+	// The minimum time this connection can be idle before sending a heartbeat.
+	HeartbeatInterval time.Duration
+	// The minimum number of heartbeats to send before terminating the connection.
+	MaxHeartbeats uint64
+	// Logger to use
+	Logger             *log.Entry
+	CompressionQuality CompressionSetting
+}
+
+type Muxer struct {
+	// f is used to read and write HTTP2 frames on the wire.
+	f *http2.Framer
+	// config is the MuxerConfig given in Handshake.
+	config MuxerConfig
+	// w, r are references to the underlying connection used.
+	w io.WriteCloser
+	r io.ReadCloser
+	// muxReader is the read process.
+	muxReader *MuxReader
+	// muxWriter is the write process.
+	muxWriter *MuxWriter
+	// muxMetricsUpdater is the process to update metrics
+	muxMetricsUpdater *muxMetricsUpdater
+	// newStreamChan is used to create new streams on the writer thread.
+	// The writer will assign the next available stream ID.
+	newStreamChan chan MuxedStreamRequest
+	// abortChan is used to abort the writer event loop.
+	abortChan chan struct{}
+	// abortOnce is used to ensure abortChan is closed once only.
+	abortOnce sync.Once
+	// readyList is used to signal writable streams.
+	readyList *ReadyList
+	// streams tracks currently-open streams.
+	streams *activeStreamMap
+	// explicitShutdown records whether the Muxer is closing because Shutdown was called, or due to another
+	// error.
+	explicitShutdown *BooleanFuse
+
+	compressionQuality CompressionPreset
+}
+
+type Header struct {
+	Name, Value string
+}
+
+// Handshake establishes a muxed connection with the peer.
+// After the handshake completes, it is possible to open and accept streams.
+func Handshake(
+	w io.WriteCloser,
+	r io.ReadCloser,
+	config MuxerConfig,
+) (*Muxer, error) {
+	// Set default config values
+	if config.Timeout == 0 {
+		config.Timeout = defaultTimeout
+	}
+	// Initialise connection state fields
+	m := &Muxer{
+		f:             http2.NewFramer(w, r), // A framer that writes to w and reads from r
+		config:        config,
+		w:             w,
+		r:             r,
+		newStreamChan: make(chan MuxedStreamRequest),
+		abortChan:     make(chan struct{}),
+		readyList:     NewReadyList(),
+		streams:       newActiveStreamMap(config.IsClient),
+	}
+
+	m.f.ReadMetaHeaders = hpack.NewDecoder(4096, func(hpack.HeaderField) {})
+	// Initialise the settings to identify this connection and confirm the other end is sane.
+	handshakeSetting := http2.Setting{ID: SettingMuxerMagic, Val: MuxerMagicEdge}
+	compressionSetting := http2.Setting{ID: SettingCompression, Val: config.CompressionQuality.toH2Setting()}
+	if CompressionIsSupported() {
+		log.Debug("Compression is supported")
+		m.compressionQuality = config.CompressionQuality.getPreset()
+	} else {
+		log.Debug("Compression is not supported")
+		compressionSetting = http2.Setting{ID: SettingCompression, Val: 0}
+	}
+
+	expectedMagic := MuxerMagicOrigin
+	if config.IsClient {
+		handshakeSetting.Val = MuxerMagicOrigin
+		expectedMagic = MuxerMagicEdge
+	}
+	errChan := make(chan error, 2)
+	// Simultaneously send our settings and verify the peer's settings.
+	go func() { errChan <- m.f.WriteSettings(handshakeSetting, compressionSetting) }()
+	go func() { errChan <- m.readPeerSettings(expectedMagic) }()
+	err := joinErrorsWithTimeout(errChan, 2, config.Timeout, ErrHandshakeTimeout)
+	if err != nil {
+		return nil, err
+	}
+	// Confirm sanity by ACKing the frame and expecting an ACK for our frame.
+	// Not strictly necessary, but let's pretend to be H2-like.
+	go func() { errChan <- m.f.WriteSettingsAck() }()
+	go func() { errChan <- m.readPeerSettingsAck() }()
+	err = joinErrorsWithTimeout(errChan, 2, config.Timeout, ErrHandshakeTimeout)
+	if err != nil {
+		return nil, err
+	}
+
+	// set up reader/writer pair ready for serve
+	streamErrors := NewStreamErrorMap()
+	goAwayChan := make(chan http2.ErrCode, 1)
+	updateRTTChan := make(chan *roundTripMeasurement, 1)
+	updateReceiveWindowChan := make(chan uint32, 1)
+	updateSendWindowChan := make(chan uint32, 1)
+	updateInBoundBytesChan := make(chan uint64)
+	updateOutBoundBytesChan := make(chan uint64)
+	inBoundCounter := NewAtomicCounter(0)
+	outBoundCounter := NewAtomicCounter(0)
+	pingTimestamp := NewPingTimestamp()
+	connActive := NewSignal()
+	idleDuration := config.HeartbeatInterval
+	// Sanity check to enusre idelDuration is sane
+	if idleDuration == 0 || idleDuration < defaultTimeout {
+		idleDuration = defaultTimeout
+		config.Logger.Warn("Minimum idle time has been adjusted to ", defaultTimeout)
+	}
+	maxRetries := config.MaxHeartbeats
+	if maxRetries == 0 {
+		maxRetries = defaultRetries
+		config.Logger.Warn("Minimum number of unacked heartbeats to send before closing the connection has been adjusted to ", maxRetries)
+	}
+
+	m.explicitShutdown = NewBooleanFuse()
+	m.muxReader = &MuxReader{
+		f:                       m.f,
+		handler:                 m.config.Handler,
+		streams:                 m.streams,
+		readyList:               m.readyList,
+		streamErrors:            streamErrors,
+		goAwayChan:              goAwayChan,
+		abortChan:               m.abortChan,
+		pingTimestamp:           pingTimestamp,
+		connActive:              connActive,
+		initialStreamWindow:     defaultWindowSize,
+		streamWindowMax:         maxWindowSize,
+		r:                       m.r,
+		updateRTTChan:           updateRTTChan,
+		updateReceiveWindowChan: updateReceiveWindowChan,
+		updateSendWindowChan:    updateSendWindowChan,
+		bytesRead:               inBoundCounter,
+		updateInBoundBytesChan:  updateInBoundBytesChan,
+	}
+	m.muxWriter = &MuxWriter{
+		f:                       m.f,
+		streams:                 m.streams,
+		streamErrors:            streamErrors,
+		readyStreamChan:         m.readyList.ReadyChannel(),
+		newStreamChan:           m.newStreamChan,
+		goAwayChan:              goAwayChan,
+		abortChan:               m.abortChan,
+		pingTimestamp:           pingTimestamp,
+		idleTimer:               NewIdleTimer(idleDuration, maxRetries),
+		connActiveChan:          connActive.WaitChannel(),
+		maxFrameSize:            defaultFrameSize,
+		updateReceiveWindowChan: updateReceiveWindowChan,
+		updateSendWindowChan:    updateSendWindowChan,
+		bytesWrote:              outBoundCounter,
+		updateOutBoundBytesChan: updateOutBoundBytesChan,
+	}
+	m.muxWriter.headerEncoder = hpack.NewEncoder(&m.muxWriter.headerBuffer)
+
+	compBytesBefore, compBytesAfter := NewAtomicCounter(0), NewAtomicCounter(0)
+
+	m.muxMetricsUpdater = newMuxMetricsUpdater(
+		updateRTTChan,
+		updateReceiveWindowChan,
+		updateSendWindowChan,
+		updateInBoundBytesChan,
+		updateOutBoundBytesChan,
+		m.abortChan,
+		compBytesBefore,
+		compBytesAfter,
+	)
+
+	if m.compressionQuality.dictSize > 0 && m.compressionQuality.nDicts > 0 {
+		nd, sz := m.compressionQuality.nDicts, m.compressionQuality.dictSize
+		writeDicts, dictChan := newH2WriteDictionaries(
+			nd,
+			sz,
+			m.compressionQuality.quality,
+			compBytesBefore,
+			compBytesAfter,
+		)
+		readDicts := newH2ReadDictionaries(nd, sz)
+		m.muxReader.dictionaries = h2Dictionaries{read: &readDicts, write: writeDicts}
+		m.muxWriter.useDictChan = dictChan
+	}
+
+	return m, nil
+}
+
+func (m *Muxer) readPeerSettings(magic uint32) error {
+	frame, err := m.f.ReadFrame()
+	if err != nil {
+		return err
+	}
+	settingsFrame, ok := frame.(*http2.SettingsFrame)
+	if !ok {
+		return ErrBadHandshakeNotSettings
+	}
+	if settingsFrame.Header().Flags != 0 {
+		return ErrBadHandshakeUnexpectedAck
+	}
+	peerMagic, ok := settingsFrame.Value(SettingMuxerMagic)
+	if !ok {
+		return ErrBadHandshakeNoMagic
+	}
+	if magic != peerMagic {
+		return ErrBadHandshakeWrongMagic
+	}
+	peerCompression, ok := settingsFrame.Value(SettingCompression)
+	if !ok {
+		m.compressionQuality = compressionPresets[CompressionNone]
+		return nil
+	}
+	ver, fmt, sz, nd := parseCompressionSettingVal(peerCompression)
+	if ver != compressionVersion || fmt != compressionFormat || sz == 0 || nd == 0 {
+		m.compressionQuality = compressionPresets[CompressionNone]
+		return nil
+	}
+	// Values used for compression are the mimimum between the two peers
+	if sz < m.compressionQuality.dictSize {
+		m.compressionQuality.dictSize = sz
+	}
+	if nd < m.compressionQuality.nDicts {
+		m.compressionQuality.nDicts = nd
+	}
+	return nil
+}
+
+func (m *Muxer) readPeerSettingsAck() error {
+	frame, err := m.f.ReadFrame()
+	if err != nil {
+		return err
+	}
+	settingsFrame, ok := frame.(*http2.SettingsFrame)
+	if !ok {
+		return ErrBadHandshakeNotSettingsAck
+	}
+	if settingsFrame.Header().Flags != http2.FlagSettingsAck {
+		return ErrBadHandshakeUnexpectedSettings
+	}
+	return nil
+}
+
+func joinErrorsWithTimeout(errChan <-chan error, receiveCount int, timeout time.Duration, timeoutError error) error {
+	for i := 0; i < receiveCount; i++ {
+		select {
+		case err := <-errChan:
+			if err != nil {
+				return err
+			}
+		case <-time.After(timeout):
+			return timeoutError
+		}
+	}
+	return nil
+}
+
+func (m *Muxer) Serve(ctx context.Context) error {
+	errGroup, _ := errgroup.WithContext(ctx)
+	errGroup.Go(func() error {
+		err := m.muxReader.run(m.config.Logger)
+		m.explicitShutdown.Fuse(false)
+		m.r.Close()
+		m.abort()
+		return err
+	})
+
+	errGroup.Go(func() error {
+		err := m.muxWriter.run(m.config.Logger)
+		m.explicitShutdown.Fuse(false)
+		m.w.Close()
+		m.abort()
+		return err
+	})
+
+	errGroup.Go(func() error {
+		err := m.muxMetricsUpdater.run(m.config.Logger)
+		return err
+	})
+
+	err := errGroup.Wait()
+	if isUnexpectedTunnelError(err, m.explicitShutdown.Value()) {
+		return err
+	}
+	return nil
+}
+
+func (m *Muxer) Shutdown() {
+	m.explicitShutdown.Fuse(true)
+	m.muxReader.Shutdown()
+}
+
+// IsUnexpectedTunnelError identifies errors that are expected when shutting down the h2mux tunnel.
+// The set of expected errors change depending on whether we initiated shutdown or not.
+func isUnexpectedTunnelError(err error, expectedShutdown bool) bool {
+	if err == nil {
+		return false
+	}
+	if !expectedShutdown {
+		return true
+	}
+	return !isConnectionClosedError(err)
+}
+
+func isConnectionClosedError(err error) bool {
+	if err == io.EOF {
+		return true
+	}
+	if err == io.ErrClosedPipe {
+		return true
+	}
+	if err.Error() == "tls: use of closed connection" {
+		return true
+	}
+	if strings.HasSuffix(err.Error(), "use of closed network connection") {
+		return true
+	}
+	return false
+}
+
+// OpenStream opens a new data stream with the given headers.
+// Called by proxy server and tunnel
+func (m *Muxer) OpenStream(headers []Header, body io.Reader) (*MuxedStream, error) {
+	stream := &MuxedStream{
+		responseHeadersReceived: make(chan struct{}),
+		readBuffer:              NewSharedBuffer(),
+		writeBuffer:             &bytes.Buffer{},
+		receiveWindow:           defaultWindowSize,
+		receiveWindowCurrentMax: defaultWindowSize, // Initial window size limit. exponentially increase it when receiveWindow is exhausted
+		receiveWindowMax:        maxWindowSize,
+		sendWindow:              defaultWindowSize,
+		readyList:               m.readyList,
+		writeHeaders:            headers,
+		dictionaries:            m.muxReader.dictionaries,
+	}
+
+	select {
+	// Will be received by mux writer
+	case m.newStreamChan <- MuxedStreamRequest{stream: stream, body: body}:
+	case <-m.abortChan:
+		return nil, ErrConnectionClosed
+	}
+	select {
+	case <-stream.responseHeadersReceived:
+		return stream, nil
+	case <-m.abortChan:
+		return nil, ErrConnectionClosed
+	}
+}
+
+func (m *Muxer) Metrics() *MuxerMetrics {
+	return m.muxMetricsUpdater.Metrics()
+}
+
+func (m *Muxer) abort() {
+	m.abortOnce.Do(func() {
+		close(m.abortChan)
+		m.streams.Abort()
+	})
+}
+
+// Return how many retries/ticks since the connection was last marked active
+func (m *Muxer) TimerRetries() uint64 {
+	return m.muxWriter.idleTimer.RetryCount()
+}

h2mux/h2mux_test.go

@@ -0,0 +1,960 @@
+package h2mux
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math/rand"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+)
+
+func TestMain(m *testing.M) {
+	if os.Getenv("VERBOSE") == "1" {
+		log.SetLevel(log.DebugLevel)
+	}
+	os.Exit(m.Run())
+}
+
+type DefaultMuxerPair struct {
+	OriginMuxConfig MuxerConfig
+	OriginMux       *Muxer
+	OriginConn      net.Conn
+	EdgeMuxConfig   MuxerConfig
+	EdgeMux         *Muxer
+	EdgeConn        net.Conn
+	doneC           chan struct{}
+}
+
+func NewDefaultMuxerPair() *DefaultMuxerPair {
+	origin, edge := net.Pipe()
+	return &DefaultMuxerPair{
+		OriginMuxConfig: MuxerConfig{
+			Timeout: time.Second,
+			IsClient: true,
+			Name: "origin",
+			Logger: log.NewEntry(log.New()),
+		},
+		OriginConn:      origin,
+		EdgeMuxConfig:   MuxerConfig{
+			Timeout: time.Second,
+			IsClient: false,
+			Name: "edge",
+			Logger: log.NewEntry(log.New()),
+		},
+		EdgeConn:        edge,
+		doneC:           make(chan struct{}),
+	}
+}
+
+func NewCompressedMuxerPair(quality CompressionSetting) *DefaultMuxerPair {
+	origin, edge := net.Pipe()
+	return &DefaultMuxerPair{
+		OriginMuxConfig: MuxerConfig{
+			Timeout: time.Second,
+			IsClient: true,
+			Name: "origin",
+			CompressionQuality: quality,
+			Logger: log.NewEntry(log.New()),
+		},
+		OriginConn:      origin,
+		EdgeMuxConfig:   MuxerConfig{
+			Timeout: time.Second,
+			IsClient: false,
+			Name: "edge",
+			CompressionQuality: quality,
+			Logger: log.NewEntry(log.New()),
+		},
+		EdgeConn:        edge,
+		doneC:           make(chan struct{}),
+	}
+}
+
+func (p *DefaultMuxerPair) Handshake(t *testing.T) {
+	edgeErrC := make(chan error)
+	originErrC := make(chan error)
+	go func() {
+		var err error
+		p.EdgeMux, err = Handshake(p.EdgeConn, p.EdgeConn, p.EdgeMuxConfig)
+		edgeErrC <- err
+	}()
+	go func() {
+		var err error
+		p.OriginMux, err = Handshake(p.OriginConn, p.OriginConn, p.OriginMuxConfig)
+		originErrC <- err
+	}()
+
+	select {
+	case err := <-edgeErrC:
+		if err != nil {
+			t.Fatalf("edge handshake failure: %s", err)
+		}
+	case <-time.After(time.Second * 5):
+		t.Fatalf("edge handshake timeout")
+	}
+
+	select {
+	case err := <-originErrC:
+		if err != nil {
+			t.Fatalf("origin handshake failure: %s", err)
+		}
+	case <-time.After(time.Second * 5):
+		t.Fatalf("origin handshake timeout")
+	}
+}
+
+func (p *DefaultMuxerPair) HandshakeAndServe(t *testing.T) {
+	ctx := context.Background()
+	p.Handshake(t)
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		err := p.EdgeMux.Serve(ctx)
+		if err != nil && err != io.EOF && err != io.ErrClosedPipe {
+			t.Errorf("error in edge muxer Serve(): %s", err)
+		}
+		p.OriginMux.Shutdown()
+		wg.Done()
+	}()
+	go func() {
+		err := p.OriginMux.Serve(ctx)
+		if err != nil && err != io.EOF && err != io.ErrClosedPipe {
+			t.Errorf("error in origin muxer Serve(): %s", err)
+		}
+		p.EdgeMux.Shutdown()
+		wg.Done()
+	}()
+	go func() {
+		// notify when both muxes have stopped serving
+		wg.Wait()
+		close(p.doneC)
+	}()
+}
+
+func (p *DefaultMuxerPair) Wait(t *testing.T) {
+	select {
+	case <-p.doneC:
+		return
+	case <-time.After(5 * time.Second):
+		t.Fatal("timeout waiting for shutdown")
+	}
+}
+
+func TestHandshake(t *testing.T) {
+	muxPair := NewDefaultMuxerPair()
+	muxPair.Handshake(t)
+	AssertIfPipeReadable(t, muxPair.OriginConn)
+	AssertIfPipeReadable(t, muxPair.EdgeConn)
+}
+
+func TestSingleStream(t *testing.T) {
+	closeC := make(chan struct{})
+	muxPair := NewDefaultMuxerPair()
+	muxPair.OriginMuxConfig.Handler = MuxedStreamFunc(func(stream *MuxedStream) error {
+		defer close(closeC)
+		if len(stream.Headers) != 1 {
+			t.Fatalf("expected %d headers, got %d", 1, len(stream.Headers))
+		}
+		if stream.Headers[0].Name != "test-header" {
+			t.Fatalf("expected header name %s, got %s", "test-header", stream.Headers[0].Name)
+		}
+		if stream.Headers[0].Value != "headerValue" {
+			t.Fatalf("expected header value %s, got %s", "headerValue", stream.Headers[0].Value)
+		}
+		stream.WriteHeaders([]Header{
+			{Name: "response-header", Value: "responseValue"},
+		})
+		buf := []byte("Hello world")
+		stream.Write(buf)
+		// after this receive, the edge closed the stream
+		<-closeC
+		n, err := io.ReadFull(stream, buf)
+		if n > 0 {
+			t.Fatalf("read %d bytes after EOF", n)
+		}
+		if err != io.EOF {
+			t.Fatalf("expected EOF, got %s", err)
+		}
+		return nil
+	})
+	muxPair.HandshakeAndServe(t)
+
+	stream, err := muxPair.EdgeMux.OpenStream(
+		[]Header{{Name: "test-header", Value: "headerValue"}},
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("error in OpenStream: %s", err)
+	}
+	if len(stream.Headers) != 1 {
+		t.Fatalf("expected %d headers, got %d", 1, len(stream.Headers))
+	}
+	if stream.Headers[0].Name != "response-header" {
+		t.Fatalf("expected header name %s, got %s", "response-header", stream.Headers[0].Name)
+	}
+	if stream.Headers[0].Value != "responseValue" {
+		t.Fatalf("expected header value %s, got %s", "responseValue", stream.Headers[0].Value)
+	}
+	responseBody := make([]byte, 11)
+	n, err := io.ReadFull(stream, responseBody)
+	if err != nil {
+		t.Fatalf("error from (*MuxedStream).Read: %s", err)
+	}
+	if n != len(responseBody) {
+		t.Fatalf("expected response body to have %d bytes, got %d", len(responseBody), n)
+	}
+	if string(responseBody) != "Hello world" {
+		t.Fatalf("expected response body %s, got %s", "Hello world", responseBody)
+	}
+	stream.Close()
+	closeC <- struct{}{}
+	n, err = stream.Write([]byte("aaaaa"))
+	if n > 0 {
+		t.Fatalf("wrote %d bytes after EOF", n)
+	}
+	if err != io.EOF {
+		t.Fatalf("expected EOF, got %s", err)
+	}
+	<-closeC
+}
+
+func TestSingleStreamLargeResponseBody(t *testing.T) {
+	muxPair := NewDefaultMuxerPair()
+	bodySize := 1 << 24
+	streamReady := make(chan struct{})
+	muxPair.OriginMuxConfig.Handler = MuxedStreamFunc(func(stream *MuxedStream) error {
+		if len(stream.Headers) != 1 {
+			t.Fatalf("expected %d headers, got %d", 1, len(stream.Headers))
+		}
+		if stream.Headers[0].Name != "test-header" {
+			t.Fatalf("expected header name %s, got %s", "test-header", stream.Headers[0].Name)
+		}
+		if stream.Headers[0].Value != "headerValue" {
+			t.Fatalf("expected header value %s, got %s", "headerValue", stream.Headers[0].Value)
+		}
+		stream.WriteHeaders([]Header{
+			{Name: "response-header", Value: "responseValue"},
+		})
+		payload := make([]byte, bodySize)
+		for i := range payload {
+			payload[i] = byte(i % 256)
+		}
+		t.Log("Writing payload...")
+		n, err := stream.Write(payload)
+		t.Logf("Wrote %d bytes into the stream", n)
+		if err != nil {
+			t.Fatalf("origin write error: %s", err)
+		}
+		if n != len(payload) {
+			t.Fatalf("origin short write: %d/%d bytes", n, len(payload))
+		}
+		t.Log("Payload written; signaling that the stream is ready")
+		streamReady <- struct{}{}
+
+		return nil
+	})
+	muxPair.HandshakeAndServe(t)
+
+	stream, err := muxPair.EdgeMux.OpenStream(
+		[]Header{{Name: "test-header", Value: "headerValue"}},
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("error in OpenStream: %s", err)
+	}
+	if len(stream.Headers) != 1 {
+		t.Fatalf("expected %d headers, got %d", 1, len(stream.Headers))
+	}
+	if stream.Headers[0].Name != "response-header" {
+		t.Fatalf("expected header name %s, got %s", "response-header", stream.Headers[0].Name)
+	}
+	if stream.Headers[0].Value != "responseValue" {
+		t.Fatalf("expected header value %s, got %s", "responseValue", stream.Headers[0].Value)
+	}
+	responseBody := make([]byte, bodySize)
+
+	<-streamReady
+	t.Log("Received stream ready signal; resuming the test")
+
+	n, err := io.ReadFull(stream, responseBody)
+	if err != nil {
+		t.Fatalf("error from (*MuxedStream).Read: %s", err)
+	}
+	if n != len(responseBody) {
+		t.Fatalf("expected response body to have %d bytes, got %d", len(responseBody), n)
+	}
+}
+
+func TestMultipleStreams(t *testing.T) {
+	muxPair := NewDefaultMuxerPair()
+	maxStreams := 64
+	errorsC := make(chan error, maxStreams)
+	muxPair.OriginMuxConfig.Handler = MuxedStreamFunc(func(stream *MuxedStream) error {
+		if len(stream.Headers) != 1 {
+			t.Fatalf("expected %d headers, got %d", 1, len(stream.Headers))
+		}
+		if stream.Headers[0].Name != "client-token" {
+			t.Fatalf("expected header name %s, got %s", "client-token", stream.Headers[0].Name)
+		}
+		log.Debugf("Got request for stream %s", stream.Headers[0].Value)
+		stream.WriteHeaders([]Header{
+			{Name: "response-token", Value: stream.Headers[0].Value},
+		})
+		log.Debugf("Wrote headers for stream %s", stream.Headers[0].Value)
+		stream.Write([]byte("OK"))
+		log.Debugf("Wrote body for stream %s", stream.Headers[0].Value)
+		return nil
+	})
+	muxPair.HandshakeAndServe(t)
+
+	var wg sync.WaitGroup
+	wg.Add(maxStreams)
+	for i := 0; i < maxStreams; i++ {
+		go func(tokenId int) {
+			defer wg.Done()
+			tokenString := fmt.Sprintf("%d", tokenId)
+			stream, err := muxPair.EdgeMux.OpenStream(
+				[]Header{{Name: "client-token", Value: tokenString}},
+				nil,
+			)
+			log.Debugf("Got headers for stream %d", tokenId)
+			if err != nil {
+				errorsC <- err
+				return
+			}
+			if len(stream.Headers) != 1 {
+				errorsC <- fmt.Errorf("stream %d has error: expected %d headers, got %d", stream.streamID, 1, len(stream.Headers))
+				return
+			}
+			if stream.Headers[0].Name != "response-token" {
+				errorsC <- fmt.Errorf("stream %d has error: expected header name %s, got %s", stream.streamID, "response-token", stream.Headers[0].Name)
+				return
+			}
+			if stream.Headers[0].Value != tokenString {
+				errorsC <- fmt.Errorf("stream %d has error: expected header value %s, got %s", stream.streamID, tokenString, stream.Headers[0].Value)
+				return
+			}
+			responseBody := make([]byte, 2)
+			n, err := io.ReadFull(stream, responseBody)
+			if err != nil {
+				errorsC <- fmt.Errorf("stream %d has error: error from (*MuxedStream).Read: %s", stream.streamID, err)
+				return
+			}
+			if n != len(responseBody) {
+				errorsC <- fmt.Errorf("stream %d has error: expected response body to have %d bytes, got %d", stream.streamID, len(responseBody), n)
+				return
+			}
+			if string(responseBody) != "OK" {
+				errorsC <- fmt.Errorf("stream %d has error: expected response body %s, got %s", stream.streamID, "OK", responseBody)
+				return
+			}
+		}(i)
+	}
+	wg.Wait()
+	close(errorsC)
+	testFail := false
+	for err := range errorsC {
+		testFail = true
+		log.Error(err)
+	}
+	if testFail {
+		t.Fatalf("TestMultipleStreamsFlowControl failed")
+	}
+}
+
+func TestMultipleStreamsFlowControl(t *testing.T) {
+	maxStreams := 32
+	errorsC := make(chan error, maxStreams)
+	streamReady := make(chan struct{})
+	responseSizes := make([]int32, maxStreams)
+	for i := 0; i < maxStreams; i++ {
+		responseSizes[i] = rand.Int31n(int32(defaultWindowSize << 4))
+	}
+	muxPair := NewDefaultMuxerPair()
+	muxPair.OriginMuxConfig.Handler = MuxedStreamFunc(func(stream *MuxedStream) error {
+		if len(stream.Headers) != 1 {
+			t.Fatalf("expected %d headers, got %d", 1, len(stream.Headers))
+		}
+		if stream.Headers[0].Name != "test-header" {
+			t.Fatalf("expected header name %s, got %s", "test-header", stream.Headers[0].Name)
+		}
+		if stream.Headers[0].Value != "headerValue" {
+			t.Fatalf("expected header value %s, got %s", "headerValue", stream.Headers[0].Value)
+		}
+		stream.WriteHeaders([]Header{
+			{Name: "response-header", Value: "responseValue"},
+		})
+		payload := make([]byte, responseSizes[(stream.streamID-2)/2])
+		for i := range payload {
+			payload[i] = byte(i % 256)
+		}
+		n, err := stream.Write(payload)
+		streamReady <- struct{}{}
+		if err != nil {
+			t.Fatalf("origin write error: %s", err)
+		}
+		if n != len(payload) {
+			t.Fatalf("origin short write: %d/%d bytes", n, len(payload))
+		}
+		return nil
+	})
+	muxPair.HandshakeAndServe(t)
+
+	var wg sync.WaitGroup
+	wg.Add(maxStreams)
+	for i := 0; i < maxStreams; i++ {
+		go func(tokenId int) {
+			defer wg.Done()
+			stream, err := muxPair.EdgeMux.OpenStream(
+				[]Header{{Name: "test-header", Value: "headerValue"}},
+				nil,
+			)
+			if err != nil {
+				errorsC <- fmt.Errorf("stream %d error in OpenStream: %s", stream.streamID, err)
+				return
+			}
+			if len(stream.Headers) != 1 {
+				errorsC <- fmt.Errorf("stream %d expected %d headers, got %d", stream.streamID, 1, len(stream.Headers))
+				return
+			}
+			if stream.Headers[0].Name != "response-header" {
+				errorsC <- fmt.Errorf("stream %d expected header name %s, got %s", stream.streamID, "response-header", stream.Headers[0].Name)
+				return
+			}
+			if stream.Headers[0].Value != "responseValue" {
+				errorsC <- fmt.Errorf("stream %d expected header value %s, got %s", stream.streamID, "responseValue", stream.Headers[0].Value)
+				return
+			}
+
+			<-streamReady
+			responseBody := make([]byte, responseSizes[(stream.streamID-2)/2])
+			n, err := io.ReadFull(stream, responseBody)
+			if err != nil {
+				errorsC <- fmt.Errorf("stream %d error from (*MuxedStream).Read: %s", stream.streamID, err)
+				return
+			}
+			if n != len(responseBody) {
+				errorsC <- fmt.Errorf("stream %d expected response body to have %d bytes, got %d", stream.streamID, len(responseBody), n)
+				return
+			}
+		}(i)
+	}
+	wg.Wait()
+	close(errorsC)
+	testFail := false
+	for err := range errorsC {
+		testFail = true
+		log.Error(err)
+	}
+	if testFail {
+		t.Fatalf("TestMultipleStreamsFlowControl failed")
+	}
+}
+
+func TestGracefulShutdown(t *testing.T) {
+	sendC := make(chan struct{})
+	responseBuf := bytes.Repeat([]byte("Hello world"), 65536)
+	muxPair := NewDefaultMuxerPair()
+	muxPair.OriginMuxConfig.Handler = MuxedStreamFunc(func(stream *MuxedStream) error {
+		stream.WriteHeaders([]Header{
+			{Name: "response-header", Value: "responseValue"},
+		})
+		<-sendC
+		log.Debugf("Writing %d bytes", len(responseBuf))
+		stream.Write(responseBuf)
+		stream.CloseWrite()
+		log.Debugf("Wrote %d bytes", len(responseBuf))
+		// Reading from the stream will block until the edge closes its end of the stream.
+		// Otherwise, we'll close the whole connection before receiving the 'stream closed'
+		// message from the edge.
+		// Graceful shutdown works if you omit this, it just gives spurious errors for now -
+		// TODO ignore errors when writing 'stream closed' and we're shutting down.
+		stream.Read([]byte{0})
+		log.Debugf("Handler ends")
+		return nil
+	})
+	muxPair.HandshakeAndServe(t)
+
+	stream, err := muxPair.EdgeMux.OpenStream(
+		[]Header{{Name: "test-header", Value: "headerValue"}},
+		nil,
+	)
+	// Start graceful shutdown of the edge mux - this should also close the origin mux when done
+	muxPair.EdgeMux.Shutdown()
+	close(sendC)
+	if err != nil {
+		t.Fatalf("error in OpenStream: %s", err)
+	}
+	responseBody := make([]byte, len(responseBuf))
+	log.Debugf("Waiting for %d bytes", len(responseBuf))
+	n, err := io.ReadFull(stream, responseBody)
+	if err != nil {
+		t.Fatalf("error from (*MuxedStream).Read with %d bytes read: %s", n, err)
+	}
+	if n != len(responseBody) {
+		t.Fatalf("expected response body to have %d bytes, got %d", len(responseBody), n)
+	}
+	if !bytes.Equal(responseBuf, responseBody) {
+		t.Fatalf("response body mismatch")
+	}
+	stream.Close()
+	muxPair.Wait(t)
+}
+
+func TestUnexpectedShutdown(t *testing.T) {
+	sendC := make(chan struct{})
+	handlerFinishC := make(chan struct{})
+	responseBuf := bytes.Repeat([]byte("Hello world"), 65536)
+	muxPair := NewDefaultMuxerPair()
+	muxPair.OriginMuxConfig.Handler = MuxedStreamFunc(func(stream *MuxedStream) error {
+		defer close(handlerFinishC)
+		stream.WriteHeaders([]Header{
+			{Name: "response-header", Value: "responseValue"},
+		})
+		<-sendC
+		n, err := stream.Read([]byte{0})
+		if err != io.EOF {
+			t.Fatalf("unexpected error from (*MuxedStream).Read: %s", err)
+		}
+		if n != 0 {
+			t.Fatalf("expected empty read, got %d bytes", n)
+		}
+		// Write comes after read, because write buffers data before it is flushed. It wouldn't know about EOF
+		// until some time later. Calling read first forces it to know about EOF now.
+		_, err = stream.Write(responseBuf)
+		if err != io.EOF {
+			t.Fatalf("unexpected error from (*MuxedStream).Write: %s", err)
+		}
+		return nil
+	})
+	muxPair.HandshakeAndServe(t)
+
+	stream, err := muxPair.EdgeMux.OpenStream(
+		[]Header{{Name: "test-header", Value: "headerValue"}},
+		nil,
+	)
+	// Close the underlying connection before telling the origin to write.
+	muxPair.EdgeConn.Close()
+	close(sendC)
+	if err != nil {
+		t.Fatalf("error in OpenStream: %s", err)
+	}
+	responseBody := make([]byte, len(responseBuf))
+	n, err := io.ReadFull(stream, responseBody)
+	if err != io.EOF {
+		t.Fatalf("unexpected error from (*MuxedStream).Read: %s", err)
+	}
+	if n != 0 {
+		t.Fatalf("expected response body to have %d bytes, got %d", 0, n)
+	}
+	// The write ordering requirement explained in the origin handler applies here too.
+	_, err = stream.Write(responseBuf)
+	if err != io.EOF {
+		t.Fatalf("unexpected error from (*MuxedStream).Write: %s", err)
+	}
+	<-handlerFinishC
+}
+
+func EchoHandler(stream *MuxedStream) error {
+	var buf bytes.Buffer
+	fmt.Fprintf(&buf, "Hello, world!\n\n# REQUEST HEADERS:\n\n")
+	for _, header := range stream.Headers {
+		fmt.Fprintf(&buf, "[%s] = %s\n", header.Name, header.Value)
+	}
+	stream.WriteHeaders([]Header{
+		{Name: ":status", Value: "200"},
+		{Name: "server", Value: "Echo-server/1.0"},
+		{Name: "date", Value: time.Now().Format(time.RFC850)},
+		{Name: "content-type", Value: "text/html; charset=utf-8"},
+		{Name: "content-length", Value: strconv.Itoa(buf.Len())},
+	})
+	buf.WriteTo(stream)
+	return nil
+}
+
+func TestOpenAfterDisconnect(t *testing.T) {
+	for i := 0; i < 3; i++ {
+		muxPair := NewDefaultMuxerPair()
+		muxPair.OriginMuxConfig.Handler = MuxedStreamFunc(EchoHandler)
+		muxPair.HandshakeAndServe(t)
+
+		switch i {
+		case 0:
+			// Close both directions of the connection to cause EOF on both peers.
+			muxPair.OriginConn.Close()
+			muxPair.EdgeConn.Close()
+		case 1:
+			// Close origin conn to cause EOF on origin first.
+			muxPair.OriginConn.Close()
+		case 2:
+			// Close edge conn to cause EOF on edge first.
+			muxPair.EdgeConn.Close()
+		}
+
+		_, err := muxPair.EdgeMux.OpenStream(
+			[]Header{{Name: "test-header", Value: "headerValue"}},
+			nil,
+		)
+		if err != ErrConnectionClosed {
+			t.Fatalf("unexpected error in OpenStream: %s", err)
+		}
+	}
+}
+
+func TestHPACK(t *testing.T) {
+	muxPair := NewDefaultMuxerPair()
+	muxPair.OriginMuxConfig.Handler = MuxedStreamFunc(EchoHandler)
+	muxPair.HandshakeAndServe(t)
+
+	stream, err := muxPair.EdgeMux.OpenStream(
+		[]Header{
+			{Name: ":method", Value: "RPC"},
+			{Name: ":scheme", Value: "capnp"},
+			{Name: ":path", Value: "*"},
+		},
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("error in OpenStream: %s", err)
+	}
+	stream.Close()
+
+	for i := 0; i < 3; i++ {
+		stream, err := muxPair.EdgeMux.OpenStream(
+			[]Header{
+				{Name: ":method", Value: "GET"},
+				{Name: ":scheme", Value: "https"},
+				{Name: ":authority", Value: "tunnel.otterlyadorable.co.uk"},
+				{Name: ":path", Value: "/get"},
+				{Name: "accept-encoding", Value: "gzip"},
+				{Name: "cf-ray", Value: "378948953f044408-SFO-DOG"},
+				{Name: "cf-visitor", Value: "{\"scheme\":\"https\"}"},
+				{Name: "cf-connecting-ip", Value: "2400:cb00:0025:010d:0000:0000:0000:0001"},
+				{Name: "x-forwarded-for", Value: "2400:cb00:0025:010d:0000:0000:0000:0001"},
+				{Name: "x-forwarded-proto", Value: "https"},
+				{Name: "accept-language", Value: "en-gb"},
+				{Name: "referer", Value: "https://tunnel.otterlyadorable.co.uk/"},
+				{Name: "cookie", Value: "__cfduid=d4555095065f92daedc059490771967d81493032162"},
+				{Name: "connection", Value: "Keep-Alive"},
+				{Name: "cf-ipcountry", Value: "US"},
+				{Name: "accept", Value: "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"},
+				{Name: "user-agent", Value: "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_5) AppleWebKit/603.2.4 (KHTML, like Gecko) Version/10.1.1 Safari/603.2.4"},
+			},
+			nil,
+		)
+		if err != nil {
+			t.Fatalf("error in OpenStream: %s", err)
+		}
+		if len(stream.Headers) == 0 {
+			t.Fatal("response has no headers")
+		}
+		if stream.Headers[0].Name != ":status" {
+			t.Fatalf("first header should be status, found %s instead", stream.Headers[0].Name)
+		}
+		if stream.Headers[0].Value != "200" {
+			t.Fatalf("expected status 200, got %s", stream.Headers[0].Value)
+		}
+		ioutil.ReadAll(stream)
+		stream.Close()
+	}
+}
+
+func AssertIfPipeReadable(t *testing.T, pipe io.ReadCloser) {
+	errC := make(chan error)
+	go func() {
+		b := []byte{0}
+		n, err := pipe.Read(b)
+		if n > 0 {
+			t.Fatalf("read pipe was not empty")
+		}
+		errC <- err
+	}()
+	select {
+	case err := <-errC:
+		if err != nil {
+			t.Fatalf("read error: %s", err)
+		}
+	case <-time.After(100 * time.Millisecond):
+		// nothing to read
+	}
+}
+
+func TestMultipleStreamsWithDictionaries(t *testing.T) {
+
+	for q := CompressionNone; q <= CompressionMax; q++ {
+		muxPair := NewCompressedMuxerPair(q)
+
+		htmlBody := `<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"` +
+			`"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">` +
+			`<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">` +
+			`<head>` +
+			`  <title>Your page title here</title>` +
+			`</head>` +
+			`<body>` +
+			`<h1>Your major heading here</h1>` +
+			`<p>` +
+			`This is a regular text paragraph.` +
+			`</p>` +
+			`<ul>` +
+			`  <li>` +
+			`  First bullet of a bullet list.` +
+			`  </li>` +
+			`  <li>` +
+			`  This is the <em>second</em> bullet.` +
+			`  </li>` +
+			`</ul>` +
+			`</body>` +
+			`</html>`
+
+		muxPair.OriginMuxConfig.Handler = MuxedStreamFunc(func(stream *MuxedStream) error {
+			var contentType string
+			var pathHeader Header
+
+			for _, h := range stream.Headers {
+				if h.Name == ":path" {
+					pathHeader = h
+					break
+				}
+			}
+
+			if pathHeader.Name != ":path" {
+				panic("Couldn't find :path header in test")
+			}
+
+			if strings.Contains(pathHeader.Value, "html") {
+				contentType = "text/html; charset=utf-8"
+			} else if strings.Contains(pathHeader.Value, "js") {
+				contentType = "application/javascript"
+			} else if strings.Contains(pathHeader.Value, "css") {
+				contentType = "text/css"
+			} else {
+				contentType = "img/gif"
+			}
+
+			stream.WriteHeaders([]Header{
+				Header{Name: "content-type", Value: contentType},
+			})
+			stream.Write([]byte(strings.Replace(htmlBody, "paragraph", pathHeader.Value, 1) + stream.Headers[5].Value))
+
+			return nil
+		})
+
+		muxPair.HandshakeAndServe(t)
+
+		var wg sync.WaitGroup
+
+		paths := []string{
+			"/html1",
+			"/html2?sa:ds",
+			"/html3",
+			"/css1",
+			"/html1",
+			"/html2?sa:ds",
+			"/html3",
+			"/css1",
+			"/css2",
+			"/css3",
+			"/js",
+			"/js",
+			"/js",
+			"/js2",
+			"/img2",
+			"/html1",
+			"/html2?sa:ds",
+			"/html3",
+			"/css1",
+			"/css2",
+			"/css3",
+			"/js",
+			"/js",
+			"/js",
+			"/js2",
+			"/img1",
+		}
+
+		wg.Add(len(paths))
+
+		for i, s := range paths {
+			go func(i int, path string) {
+				stream, err := muxPair.EdgeMux.OpenStream(
+					[]Header{
+						{Name: ":method", Value: "GET"},
+						{Name: ":scheme", Value: "https"},
+						{Name: ":authority", Value: "tunnel.otterlyadorable.co.uk"},
+						{Name: ":path", Value: path},
+						{Name: "cf-ray", Value: "378948953f044408-SFO-DOG"},
+						{Name: "idx", Value: strconv.Itoa(i)},
+						{Name: "accept-encoding", Value: "gzip, br"},
+					},
+					nil,
+				)
+				if err != nil {
+					t.Fatalf("error in OpenStream: %s", err)
+				}
+
+				expectBody := strings.Replace(htmlBody, "paragraph", path, 1) + strconv.Itoa(i)
+				responseBody := make([]byte, len(expectBody)*2)
+				n, err := stream.Read(responseBody)
+				if err != nil {
+					log.Printf("error from (*MuxedStream).Read: %s", err)
+					t.Fatalf("error from (*MuxedStream).Read: %s", err)
+				}
+				if n != len(expectBody) {
+					log.Printf("expected response body to have %d bytes, got %d", len(expectBody), n)
+					t.Fatalf("expected response body to have %d bytes, got %d", len(expectBody), n)
+				}
+				if string(responseBody[:n]) != expectBody {
+					log.Printf("expected response body %s, got %s", expectBody, responseBody[:n])
+					t.Fatalf("expected response body %s, got %s", expectBody, responseBody[:n])
+				}
+				wg.Done()
+			}(i, s)
+			time.Sleep(1 * time.Millisecond)
+		}
+		wg.Wait()
+
+		if q > CompressionNone && muxPair.OriginMux.muxMetricsUpdater.compBytesBefore.Value() <= 10*muxPair.OriginMux.muxMetricsUpdater.compBytesAfter.Value() {
+			t.Fatalf("Cross-stream compression is expected to give a better compression ratio")
+		}
+	}
+}
+
+func sampleSiteHandler(stream *MuxedStream) error {
+	var contentType string
+	var pathHeader Header
+
+	for _, h := range stream.Headers {
+		if h.Name == ":path" {
+			pathHeader = h
+			break
+		}
+	}
+
+	if pathHeader.Name != ":path" {
+		panic("Couldn't find :path header in test")
+	}
+
+	if strings.Contains(pathHeader.Value, "html") {
+		contentType = "text/html; charset=utf-8"
+	} else if strings.Contains(pathHeader.Value, "js") {
+		contentType = "application/javascript"
+	} else if strings.Contains(pathHeader.Value, "css") {
+		contentType = "text/css"
+	} else {
+		contentType = "img/gif"
+	}
+	stream.WriteHeaders([]Header{
+		Header{Name: "content-type", Value: contentType},
+	})
+	log.Debugf("Wrote headers for stream %s", pathHeader.Value)
+	b, _ := ioutil.ReadFile("./sample" + pathHeader.Value)
+	stream.Write(b)
+	log.Debugf("Wrote body for stream %s", pathHeader.Value)
+	return nil
+}
+
+func sampleSiteTest(t *testing.T, muxPair *DefaultMuxerPair, path string) {
+	stream, err := muxPair.EdgeMux.OpenStream(
+		[]Header{
+			{Name: ":method", Value: "GET"},
+			{Name: ":scheme", Value: "https"},
+			{Name: ":authority", Value: "tunnel.otterlyadorable.co.uk"},
+			{Name: ":path", Value: path},
+			{Name: "accept-encoding", Value: "br, gzip"},
+			{Name: "cf-ray", Value: "378948953f044408-SFO-DOG"},
+		},
+		nil,
+	)
+	if err != nil {
+		t.Fatalf("error in OpenStream: %s", err)
+	}
+	expectBody, _ := ioutil.ReadFile("./sample" + path)
+	responseBody := make([]byte, len(expectBody))
+	n, err := io.ReadFull(stream, responseBody)
+	log.Debugf("Got body for stream %s", path)
+	if err != nil {
+		t.Fatalf("error from (*MuxedStream).Read: %s", err)
+	}
+	if n != len(expectBody) {
+		t.Fatalf("expected response body to have %d bytes, got %d", len(expectBody), n)
+	}
+	if string(responseBody[:n]) != string(expectBody) {
+		t.Fatalf("expected response body %s, got %s", expectBody, responseBody[:n])
+	}
+}
+
+func TestSampleSiteWithDictionaries(t *testing.T) {
+	for q := CompressionNone; q <= CompressionMax; q++ {
+		muxPair := NewCompressedMuxerPair(q)
+		muxPair.OriginMuxConfig.Handler = MuxedStreamFunc(sampleSiteHandler)
+		muxPair.HandshakeAndServe(t)
+
+		var wg sync.WaitGroup
+
+		paths := []string{
+			"/index.html",
+			"/index2.html",
+			"/index1.html",
+			"/ghost-url.min.js",
+			"/jquery.fitvids.js",
+			"/index1.html",
+			"/index2.html",
+			"/index.html",
+		}
+
+		wg.Add(len(paths))
+		for _, s := range paths {
+			go func(path string) {
+				sampleSiteTest(t, muxPair, path)
+				wg.Done()
+			}(s)
+		}
+		wg.Wait()
+
+		if q > CompressionNone && muxPair.OriginMux.muxMetricsUpdater.compBytesBefore.Value() <= 10*muxPair.OriginMux.muxMetricsUpdater.compBytesAfter.Value() {
+			t.Fatalf("Cross-stream compression is expected to give a better compression ratio")
+		}
+	}
+}
+
+func TestLongSiteWithDictionaries(t *testing.T) {
+	for q := CompressionNone; q <= CompressionMedium; q++ {
+		muxPair := NewCompressedMuxerPair(q)
+		muxPair.OriginMuxConfig.Handler = MuxedStreamFunc(sampleSiteHandler)
+		muxPair.HandshakeAndServe(t)
+
+		var wg sync.WaitGroup
+		rand.Seed(time.Now().Unix())
+
+		paths := []string{
+			"/index.html",
+			"/index1.html",
+			"/index2.html",
+			"/ghost-url.min.js",
+			"/jquery.fitvids.js"}
+
+		tstLen := 1000
+		wg.Add(tstLen)
+		for i := 0; i < tstLen; i++ {
+			path := paths[rand.Int()%len(paths)]
+			go func(path string) {
+				sampleSiteTest(t, muxPair, path)
+				wg.Done()
+			}(path)
+		}
+		wg.Wait()
+
+		if q > CompressionNone && muxPair.OriginMux.muxMetricsUpdater.compBytesBefore.Value() <= 100*muxPair.OriginMux.muxMetricsUpdater.compBytesAfter.Value() {
+			t.Fatalf("Cross-stream compression is expected to give a better compression ratio")
+		}
+	}
+}

h2mux/idletimer.go

@@ -0,0 +1,81 @@
+package h2mux
+
+import (
+	"math/rand"
+	"sync"
+	"time"
+)
+
+// IdleTimer is a type of Timer designed for managing heartbeats on an idle connection.
+// The timer ticks on an interval with added jitter to avoid accidental synchronisation
+// between two endpoints. It tracks the number of retries/ticks since the connection was
+// last marked active.
+//
+// The methods of IdleTimer must not be called while a goroutine is reading from C.
+type IdleTimer struct {
+	// The channel on which ticks are delivered.
+	C <-chan time.Time
+
+	// A timer used to measure idle connection time. Reset after sending data.
+	idleTimer *time.Timer
+	// The maximum length of time a connection is idle before sending a ping.
+	idleDuration time.Duration
+	// A pseudorandom source used to add jitter to the idle duration.
+	randomSource *rand.Rand
+	// The maximum number of retries allowed.
+	maxRetries uint64
+	// The number of retries since the connection was last marked active.
+	retries uint64
+	// A lock to prevent race condition while checking retries
+	stateLock sync.RWMutex
+}
+
+func NewIdleTimer(idleDuration time.Duration, maxRetries uint64) *IdleTimer {
+	t := &IdleTimer{
+		idleTimer:    time.NewTimer(idleDuration),
+		idleDuration: idleDuration,
+		randomSource: rand.New(rand.NewSource(time.Now().Unix())),
+		maxRetries:   maxRetries,
+	}
+	t.C = t.idleTimer.C
+	return t
+}
+
+// Retry should be called when retrying the idle timeout. If the maximum number of retries
+// has been met, returns false.
+// After calling this function and sending a heartbeat, call ResetTimer. Since sending the
+// heartbeat could be a blocking operation, we resetting the timer after the write completes
+// to avoid it expiring during the write.
+func (t *IdleTimer) Retry() bool {
+	t.stateLock.Lock()
+	defer t.stateLock.Unlock()
+	if t.retries >= t.maxRetries {
+		return false
+	}
+	t.retries++
+	return true
+}
+
+func (t *IdleTimer) RetryCount() uint64 {
+	t.stateLock.RLock()
+	defer t.stateLock.RUnlock()
+	return t.retries
+}
+
+// MarkActive resets the idle connection timer and suppresses any outstanding idle events.
+func (t *IdleTimer) MarkActive() {
+	if !t.idleTimer.Stop() {
+		// eat the timer event to prevent spurious pings
+		<-t.idleTimer.C
+	}
+	t.stateLock.Lock()
+	t.retries = 0
+	t.stateLock.Unlock()
+	t.ResetTimer()
+}
+
+// Reset the idle timer according to the configured duration, with some added jitter.
+func (t *IdleTimer) ResetTimer() {
+	jitter := time.Duration(t.randomSource.Int63n(int64(t.idleDuration)))
+	t.idleTimer.Reset(t.idleDuration + jitter)
+}

h2mux/idletimer_test.go

@@ -0,0 +1,31 @@
+package h2mux
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRetry(t *testing.T) {
+	timer := NewIdleTimer(time.Second, 2)
+	assert.Equal(t, uint64(0), timer.RetryCount())
+	ok := timer.Retry()
+	assert.True(t, ok)
+	assert.Equal(t, uint64(1), timer.RetryCount())
+	ok = timer.Retry()
+	assert.True(t, ok)
+	assert.Equal(t, uint64(2), timer.RetryCount())
+	ok = timer.Retry()
+	assert.False(t, ok)
+}
+
+func TestMarkActive(t *testing.T) {
+	timer := NewIdleTimer(time.Second, 2)
+	assert.Equal(t, uint64(0), timer.RetryCount())
+	ok := timer.Retry()
+	assert.True(t, ok)
+	assert.Equal(t, uint64(1), timer.RetryCount())
+	timer.MarkActive()
+	assert.Equal(t, uint64(0), timer.RetryCount())
+}

h2mux/muxedstream.go

@@ -0,0 +1,289 @@
+package h2mux
+
+import (
+	"bytes"
+	"io"
+	"sync"
+)
+
+type ReadWriteLengther interface {
+	io.ReadWriter
+	Reset()
+	Len() int
+}
+
+type ReadWriteClosedCloser interface {
+	io.ReadWriteCloser
+	Closed() bool
+}
+
+type MuxedStream struct {
+	Headers []Header
+
+	streamID uint32
+
+	responseHeadersReceived chan struct{}
+
+	readBuffer    ReadWriteClosedCloser
+	receiveWindow uint32
+	// current window size limit. Exponentially increase it when it's exhausted
+	receiveWindowCurrentMax uint32
+	// limit set in http2 spec. 2^31-1
+	receiveWindowMax uint32
+
+	// nonzero if a WINDOW_UPDATE frame for a stream needs to be sent
+	windowUpdate uint32
+
+	writeLock sync.Mutex
+	// The zero value for Buffer is an empty buffer ready to use.
+	writeBuffer ReadWriteLengther
+
+	sendWindow uint32
+
+	readyList    *ReadyList
+	headersSent  bool
+	writeHeaders []Header
+	// true if the write end of this stream has been closed
+	writeEOF bool
+	// true if we have sent EOF to the peer
+	sentEOF bool
+	// true if the peer sent us an EOF
+	receivedEOF bool
+
+	// dictionary that was used to compress the stream
+	receivedUseDict bool
+	method          string
+	contentType     string
+	path            string
+	dictionaries    h2Dictionaries
+	readBufferLock  sync.RWMutex
+}
+
+func (s *MuxedStream) Read(p []byte) (n int, err error) {
+	if s.dictionaries.read != nil {
+		s.readBufferLock.RLock()
+		b := s.readBuffer
+		s.readBufferLock.RUnlock()
+		return b.Read(p)
+	}
+	return s.readBuffer.Read(p)
+}
+
+func (s *MuxedStream) Write(p []byte) (n int, err error) {
+	ok := assignDictToStream(s, p)
+	if !ok {
+		s.writeLock.Lock()
+	}
+	defer s.writeLock.Unlock()
+	if s.writeEOF {
+		return 0, io.EOF
+	}
+	n, err = s.writeBuffer.Write(p)
+	if n != len(p) || err != nil {
+		return n, err
+	}
+	s.writeNotify()
+	return n, nil
+}
+
+func (s *MuxedStream) Close() error {
+	// TUN-115: Close the write buffer before the read buffer.
+	// In the case of shutdown, read will not get new data, but the write buffer can still receive
+	// new data. Closing read before write allows application to race between a failed read and a
+	// successful write, even though this close should appear to be atomic.
+	// This can't happen the other way because reads may succeed after a failed write; if we read
+	// past EOF the application will block until we close the buffer.
+	err := s.CloseWrite()
+	if err != nil {
+		if s.CloseRead() == nil {
+			// don't bother the caller with errors if at least one close succeeded
+			return nil
+		}
+		return err
+	}
+	return s.CloseRead()
+}
+
+func (s *MuxedStream) CloseRead() error {
+	return s.readBuffer.Close()
+}
+
+func (s *MuxedStream) CloseWrite() error {
+	s.writeLock.Lock()
+	defer s.writeLock.Unlock()
+	if s.writeEOF {
+		return io.EOF
+	}
+	s.writeEOF = true
+	if c, ok := s.writeBuffer.(io.Closer); ok {
+		c.Close()
+	}
+	s.writeNotify()
+	return nil
+}
+
+func (s *MuxedStream) WriteHeaders(headers []Header) error {
+	s.writeLock.Lock()
+	defer s.writeLock.Unlock()
+	if s.writeHeaders != nil {
+		return ErrStreamHeadersSent
+	}
+
+	if s.dictionaries.write != nil {
+		dictWriter := s.dictionaries.write.getDictWriter(s, headers)
+		if dictWriter != nil {
+			s.writeBuffer = dictWriter
+		}
+
+	}
+
+	s.writeHeaders = headers
+	s.headersSent = false
+	s.writeNotify()
+	return nil
+}
+
+func (s *MuxedStream) getReceiveWindow() uint32 {
+	s.writeLock.Lock()
+	defer s.writeLock.Unlock()
+	return s.receiveWindow
+}
+
+func (s *MuxedStream) getSendWindow() uint32 {
+	s.writeLock.Lock()
+	defer s.writeLock.Unlock()
+	return s.sendWindow
+}
+
+// writeNotify must happen while holding writeLock.
+func (s *MuxedStream) writeNotify() {
+	s.readyList.Signal(s.streamID)
+}
+
+// Call by muxreader when it gets a WindowUpdateFrame. This is an update of the peer's
+// receive window (how much data we can send).
+func (s *MuxedStream) replenishSendWindow(bytes uint32) {
+	s.writeLock.Lock()
+	s.sendWindow += bytes
+	s.writeNotify()
+	s.writeLock.Unlock()
+}
+
+// Call by muxreader when it receives a data frame
+func (s *MuxedStream) consumeReceiveWindow(bytes uint32) bool {
+	s.writeLock.Lock()
+	defer s.writeLock.Unlock()
+	// received data size is greater than receive window/buffer
+	if s.receiveWindow < bytes {
+		return false
+	}
+	s.receiveWindow -= bytes
+	if s.receiveWindow < s.receiveWindowCurrentMax/2 {
+		// exhausting client send window (how much data client can send)
+		if s.receiveWindowCurrentMax < s.receiveWindowMax {
+			s.receiveWindowCurrentMax <<= 1
+		}
+		s.windowUpdate += s.receiveWindowCurrentMax - s.receiveWindow
+		s.writeNotify()
+	}
+	return true
+}
+
+// receiveEOF should be called when the peer indicates no more data will be sent.
+// Returns true if the socket is now closed (i.e. the write side is already closed).
+func (s *MuxedStream) receiveEOF() (closed bool) {
+	s.writeLock.Lock()
+	defer s.writeLock.Unlock()
+	s.receivedEOF = true
+	s.CloseRead()
+	return s.writeEOF && s.writeBuffer.Len() == 0
+}
+
+func (s *MuxedStream) gotReceiveEOF() bool {
+	s.writeLock.Lock()
+	defer s.writeLock.Unlock()
+	return s.receivedEOF
+}
+
+// MuxedStreamReader implements io.ReadCloser for the read end of the stream.
+// This is useful for passing to functions that close the object after it is done reading,
+// but you still want to be able to write data afterwards (e.g. http.Client).
+type MuxedStreamReader struct {
+	*MuxedStream
+}
+
+func (s MuxedStreamReader) Read(p []byte) (n int, err error) {
+	return s.MuxedStream.Read(p)
+}
+
+func (s MuxedStreamReader) Close() error {
+	return s.MuxedStream.CloseRead()
+}
+
+// streamChunk represents a chunk of data to be written.
+type streamChunk struct {
+	streamID uint32
+	// true if a HEADERS frame should be sent
+	sendHeaders bool
+	headers     []Header
+	// nonzero if a WINDOW_UPDATE frame should be sent
+	windowUpdate uint32
+	// true if data frames should be sent
+	sendData bool
+	eof      bool
+	buffer   bytes.Buffer
+}
+
+// getChunk atomically extracts a chunk of data to be written by MuxWriter.
+// The data returned will not exceed the send window for this stream.
+func (s *MuxedStream) getChunk() *streamChunk {
+	s.writeLock.Lock()
+	defer s.writeLock.Unlock()
+
+	chunk := &streamChunk{
+		streamID:     s.streamID,
+		sendHeaders:  !s.headersSent,
+		headers:      s.writeHeaders,
+		windowUpdate: s.windowUpdate,
+		sendData:     !s.sentEOF,
+		eof:          s.writeEOF && uint32(s.writeBuffer.Len()) <= s.sendWindow,
+	}
+
+	// Copies at most s.sendWindow bytes
+	writeLen, _ := io.CopyN(&chunk.buffer, s.writeBuffer, int64(s.sendWindow))
+	s.sendWindow -= uint32(writeLen)
+	s.receiveWindow += s.windowUpdate
+	s.windowUpdate = 0
+	s.headersSent = true
+
+	// if this chunk contains the end of the stream, close the stream now
+	if chunk.sendData && chunk.eof {
+		s.sentEOF = true
+	}
+
+	return chunk
+}
+
+func (c *streamChunk) sendHeadersFrame() bool {
+	return c.sendHeaders
+}
+
+func (c *streamChunk) sendWindowUpdateFrame() bool {
+	return c.windowUpdate > 0
+}
+
+func (c *streamChunk) sendDataFrame() bool {
+	return c.sendData
+}
+
+func (c *streamChunk) nextDataFrame(frameSize int) (payload []byte, endStream bool) {
+	payload = c.buffer.Next(frameSize)
+	if c.buffer.Len() == 0 {
+		// this is the last data frame in this chunk
+		c.sendData = false
+		if c.eof {
+			endStream = true
+		}
+	}
+	return
+}

h2mux/muxedstream_test.go

@@ -0,0 +1,92 @@
+package h2mux
+
+import (
+	"bytes"
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+const testWindowSize uint32 = 65535
+const testMaxWindowSize uint32 = testWindowSize << 2
+
+// Only sending WINDOW_UPDATE frame, so sendWindow should never change
+func TestFlowControlSingleStream(t *testing.T) {
+	stream := &MuxedStream{
+		responseHeadersReceived: make(chan struct{}),
+		readBuffer:              NewSharedBuffer(),
+		writeBuffer:             &bytes.Buffer{},
+		receiveWindow:           testWindowSize,
+		receiveWindowCurrentMax: testWindowSize,
+		receiveWindowMax:        testMaxWindowSize,
+		sendWindow:              testWindowSize,
+		readyList:               NewReadyList(),
+	}
+	assert.True(t, stream.consumeReceiveWindow(testWindowSize/2))
+	dataSent := testWindowSize / 2
+	assert.Equal(t, testWindowSize-dataSent, stream.receiveWindow)
+	assert.Equal(t, testWindowSize, stream.receiveWindowCurrentMax)
+	assert.Equal(t, uint32(0), stream.windowUpdate)
+	tempWindowUpdate := stream.windowUpdate
+
+	streamChunk := stream.getChunk()
+	assert.Equal(t, tempWindowUpdate, streamChunk.windowUpdate)
+	assert.Equal(t, testWindowSize-dataSent, stream.receiveWindow)
+	assert.Equal(t, uint32(0), stream.windowUpdate)
+	assert.Equal(t, testWindowSize, stream.sendWindow)
+
+	assert.True(t, stream.consumeReceiveWindow(2))
+	dataSent += 2
+	assert.Equal(t, testWindowSize-dataSent, stream.receiveWindow)
+	assert.Equal(t, testWindowSize<<1, stream.receiveWindowCurrentMax)
+	assert.Equal(t, (testWindowSize<<1)-stream.receiveWindow, stream.windowUpdate)
+	tempWindowUpdate = stream.windowUpdate
+
+	streamChunk = stream.getChunk()
+	assert.Equal(t, tempWindowUpdate, streamChunk.windowUpdate)
+	assert.Equal(t, testWindowSize<<1, stream.receiveWindow)
+	assert.Equal(t, uint32(0), stream.windowUpdate)
+	assert.Equal(t, testWindowSize, stream.sendWindow)
+
+	assert.True(t, stream.consumeReceiveWindow(testWindowSize+10))
+	dataSent = testWindowSize + 10
+	assert.Equal(t, (testWindowSize<<1)-dataSent, stream.receiveWindow)
+	assert.Equal(t, testWindowSize<<2, stream.receiveWindowCurrentMax)
+	assert.Equal(t, (testWindowSize<<2)-stream.receiveWindow, stream.windowUpdate)
+	tempWindowUpdate = stream.windowUpdate
+
+	streamChunk = stream.getChunk()
+	assert.Equal(t, tempWindowUpdate, streamChunk.windowUpdate)
+	assert.Equal(t, testWindowSize<<2, stream.receiveWindow)
+	assert.Equal(t, uint32(0), stream.windowUpdate)
+	assert.Equal(t, testWindowSize, stream.sendWindow)
+
+	assert.False(t, stream.consumeReceiveWindow(testMaxWindowSize+1))
+	assert.Equal(t, testWindowSize<<2, stream.receiveWindow)
+	assert.Equal(t, testMaxWindowSize, stream.receiveWindowCurrentMax)
+}
+
+func TestMuxedStreamEOF(t *testing.T) {
+	for i := 0; i < 4096; i++ {
+		readyList := NewReadyList()
+		stream := &MuxedStream{
+			streamID:         1,
+			readBuffer:       NewSharedBuffer(),
+			receiveWindow:    65536,
+			receiveWindowMax: 65536,
+			sendWindow:       65536,
+			readyList:        readyList,
+		}
+
+		go func() { stream.Close() }()
+		n, err := stream.Read([]byte{0})
+		assert.Equal(t, io.EOF, err)
+		assert.Equal(t, 0, n)
+		// Write comes after read, because write buffers data before it is flushed. It wouldn't know about EOF
+		// until some time later. Calling read first forces it to know about EOF now.
+		n, err = stream.Write([]byte{1})
+		assert.Equal(t, io.EOF, err)
+		assert.Equal(t, 0, n)
+	}
+}

h2mux/muxmetrics.go

@@ -0,0 +1,246 @@
+package h2mux
+
+import (
+	"sync"
+	"time"
+
+	"github.com/golang-collections/collections/queue"
+
+	log "github.com/sirupsen/logrus"
+)
+
+// data points used to compute average receive window and send window size
+const (
+	// data points used to compute average receive window and send window size
+	dataPoints = 100
+	// updateFreq is set to 1 sec so we can get inbound & outbound byes/sec
+	updateFreq = time.Second
+)
+
+type muxMetricsUpdater struct {
+	// rttData keeps record of rtt, rttMin, rttMax and last measured time
+	rttData *rttData
+	// receiveWindowData keeps record of receive window measurement
+	receiveWindowData *flowControlData
+	// sendWindowData keeps record of send window measurement
+	sendWindowData *flowControlData
+	// inBoundRate is incoming bytes/sec
+	inBoundRate *rate
+	// outBoundRate is outgoing bytes/sec
+	outBoundRate *rate
+	// updateRTTChan is the channel to receive new RTT measurement from muxReader
+	updateRTTChan <-chan *roundTripMeasurement
+	//updateReceiveWindowChan is the channel to receive updated receiveWindow size from muxReader and muxWriter
+	updateReceiveWindowChan <-chan uint32
+	//updateSendWindowChan is the channel to receive updated sendWindow size from muxReader and muxWriter
+	updateSendWindowChan <-chan uint32
+	// updateInBoundBytesChan us the channel to receive bytesRead from muxReader
+	updateInBoundBytesChan <-chan uint64
+	// updateOutBoundBytesChan us the channel to receive bytesWrote from muxWriter
+	updateOutBoundBytesChan <-chan uint64
+	// shutdownC is to signal the muxerMetricsUpdater to shutdown
+	abortChan <-chan struct{}
+
+	compBytesBefore, compBytesAfter *AtomicCounter
+}
+
+type MuxerMetrics struct {
+	RTT, RTTMin, RTTMax                                              time.Duration
+	ReceiveWindowAve, SendWindowAve                                  float64
+	ReceiveWindowMin, ReceiveWindowMax, SendWindowMin, SendWindowMax uint32
+	InBoundRateCurr, InBoundRateMin, InBoundRateMax                  uint64
+	OutBoundRateCurr, OutBoundRateMin, OutBoundRateMax               uint64
+	CompBytesBefore, CompBytesAfter                                  *AtomicCounter
+}
+
+func (m *MuxerMetrics) CompRateAve() float64 {
+	if m.CompBytesBefore.Value() == 0 {
+		return 1.
+	}
+	return float64(m.CompBytesAfter.Value()) / float64(m.CompBytesBefore.Value())
+}
+
+type roundTripMeasurement struct {
+	receiveTime, sendTime time.Time
+}
+
+type rttData struct {
+	rtt, rttMin, rttMax time.Duration
+	lastMeasurementTime time.Time
+	lock                sync.RWMutex
+}
+
+type flowControlData struct {
+	sum      uint64
+	min, max uint32
+	queue    *queue.Queue
+	lock     sync.RWMutex
+}
+
+type rate struct {
+	curr     uint64
+	min, max uint64
+	lock     sync.RWMutex
+}
+
+func newMuxMetricsUpdater(
+	updateRTTChan <-chan *roundTripMeasurement,
+	updateReceiveWindowChan <-chan uint32,
+	updateSendWindowChan <-chan uint32,
+	updateInBoundBytesChan <-chan uint64,
+	updateOutBoundBytesChan <-chan uint64,
+	abortChan <-chan struct{},
+	compBytesBefore, compBytesAfter *AtomicCounter,
+) *muxMetricsUpdater {
+	return &muxMetricsUpdater{
+		rttData:                 newRTTData(),
+		receiveWindowData:       newFlowControlData(),
+		sendWindowData:          newFlowControlData(),
+		inBoundRate:             newRate(),
+		outBoundRate:            newRate(),
+		updateRTTChan:           updateRTTChan,
+		updateReceiveWindowChan: updateReceiveWindowChan,
+		updateSendWindowChan:    updateSendWindowChan,
+		updateInBoundBytesChan:  updateInBoundBytesChan,
+		updateOutBoundBytesChan: updateOutBoundBytesChan,
+		abortChan:               abortChan,
+		compBytesBefore:         compBytesBefore,
+		compBytesAfter:          compBytesAfter,
+	}
+}
+
+func (updater *muxMetricsUpdater) Metrics() *MuxerMetrics {
+	m := &MuxerMetrics{}
+	m.RTT, m.RTTMin, m.RTTMax = updater.rttData.metrics()
+	m.ReceiveWindowAve, m.ReceiveWindowMin, m.ReceiveWindowMax = updater.receiveWindowData.metrics()
+	m.SendWindowAve, m.SendWindowMin, m.SendWindowMax = updater.sendWindowData.metrics()
+	m.InBoundRateCurr, m.InBoundRateMin, m.InBoundRateMax = updater.inBoundRate.get()
+	m.OutBoundRateCurr, m.OutBoundRateMin, m.OutBoundRateMax = updater.outBoundRate.get()
+	m.CompBytesBefore, m.CompBytesAfter = updater.compBytesBefore, updater.compBytesAfter
+	return m
+}
+
+func (updater *muxMetricsUpdater) run(parentLogger *log.Entry) error {
+	logger := parentLogger.WithFields(log.Fields{
+		"subsystem": "mux",
+		"dir":       "metrics",
+	})
+	defer logger.Debug("event loop finished")
+	for {
+		select {
+		case <-updater.abortChan:
+			logger.Infof("Stopping mux metrics updater")
+			return nil
+		case roundTripMeasurement := <-updater.updateRTTChan:
+			go updater.rttData.update(roundTripMeasurement)
+			logger.Debug("Update rtt")
+		case receiveWindow := <-updater.updateReceiveWindowChan:
+			go updater.receiveWindowData.update(receiveWindow)
+			logger.Debug("Update receive window")
+		case sendWindow := <-updater.updateSendWindowChan:
+			go updater.sendWindowData.update(sendWindow)
+			logger.Debug("Update send window")
+		case inBoundBytes := <-updater.updateInBoundBytesChan:
+			// inBoundBytes is bytes/sec because the update interval is 1 sec
+			go updater.inBoundRate.update(inBoundBytes)
+			logger.Debugf("Inbound bytes %d", inBoundBytes)
+		case outBoundBytes := <-updater.updateOutBoundBytesChan:
+			// outBoundBytes is bytes/sec because the update interval is 1 sec
+			go updater.outBoundRate.update(outBoundBytes)
+			logger.Debugf("Outbound bytes %d", outBoundBytes)
+		}
+	}
+}
+
+func newRTTData() *rttData {
+	return &rttData{}
+}
+
+func (r *rttData) update(measurement *roundTripMeasurement) {
+	r.lock.Lock()
+	defer r.lock.Unlock()
+	// discard pings before lastMeasurementTime
+	if r.lastMeasurementTime.After(measurement.sendTime) {
+		return
+	}
+	r.lastMeasurementTime = measurement.sendTime
+	r.rtt = measurement.receiveTime.Sub(measurement.sendTime)
+	if r.rttMax < r.rtt {
+		r.rttMax = r.rtt
+	}
+	if r.rttMin == 0 || r.rttMin > r.rtt {
+		r.rttMin = r.rtt
+	}
+}
+
+func (r *rttData) metrics() (rtt, rttMin, rttMax time.Duration) {
+	r.lock.RLock()
+	defer r.lock.RUnlock()
+	return r.rtt, r.rttMin, r.rttMax
+}
+
+func newFlowControlData() *flowControlData {
+	return &flowControlData{queue: queue.New()}
+}
+
+func (f *flowControlData) update(measurement uint32) {
+	f.lock.Lock()
+	defer f.lock.Unlock()
+	var firstItem uint32
+	// store new data into queue, remove oldest data if queue is full
+	f.queue.Enqueue(measurement)
+	if f.queue.Len() > dataPoints {
+		// data type should always be uint32
+		firstItem = f.queue.Dequeue().(uint32)
+	}
+	// if (measurement - firstItem) < 0, uint64(measurement - firstItem)
+	// will overflow and become a large positive number
+	f.sum += uint64(measurement)
+	f.sum -= uint64(firstItem)
+	if measurement > f.max {
+		f.max = measurement
+	}
+	if f.min == 0 || measurement < f.min {
+		f.min = measurement
+	}
+}
+
+// caller of ave() should acquire lock first
+func (f *flowControlData) ave() float64 {
+	if f.queue.Len() == 0 {
+		return 0
+	}
+	return float64(f.sum) / float64(f.queue.Len())
+}
+
+func (f *flowControlData) metrics() (ave float64, min, max uint32) {
+	f.lock.RLock()
+	defer f.lock.RUnlock()
+	return f.ave(), f.min, f.max
+}
+
+func newRate() *rate {
+	return &rate{}
+}
+
+func (r *rate) update(measurement uint64) {
+	r.lock.Lock()
+	defer r.lock.Unlock()
+	r.curr = measurement
+	// if measurement is 0, then there is no incoming/outgoing connection, don't update min/max
+	if r.curr == 0 {
+		return
+	}
+	if measurement > r.max {
+		r.max = measurement
+	}
+	if r.min == 0 || measurement < r.min {
+		r.min = measurement
+	}
+}
+
+func (r *rate) get() (curr, min, max uint64) {
+	r.lock.RLock()
+	defer r.lock.RUnlock()
+	return r.curr, r.min, r.max
+}

h2mux/muxmetrics_test.go

@@ -0,0 +1,180 @@
+package h2mux
+
+import (
+	"sync"
+	"testing"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
+)
+
+func ave(sum uint64, len int) float64 {
+	return float64(sum) / float64(len)
+}
+
+func TestRTTUpdate(t *testing.T) {
+	r := newRTTData()
+	start := time.Now()
+	// send at 0 ms, receive at 2 ms, RTT = 2ms
+	m := &roundTripMeasurement{receiveTime: start.Add(2 * time.Millisecond), sendTime: start}
+	r.update(m)
+	assert.Equal(t, start, r.lastMeasurementTime)
+	assert.Equal(t, 2*time.Millisecond, r.rtt)
+	assert.Equal(t, 2*time.Millisecond, r.rttMin)
+	assert.Equal(t, 2*time.Millisecond, r.rttMax)
+
+	// send at 3 ms, receive at 6 ms, RTT = 3ms
+	m = &roundTripMeasurement{receiveTime: start.Add(6 * time.Millisecond), sendTime: start.Add(3 * time.Millisecond)}
+	r.update(m)
+	assert.Equal(t, start.Add(3*time.Millisecond), r.lastMeasurementTime)
+	assert.Equal(t, 3*time.Millisecond, r.rtt)
+	assert.Equal(t, 2*time.Millisecond, r.rttMin)
+	assert.Equal(t, 3*time.Millisecond, r.rttMax)
+
+	// send at 7 ms, receive at 8 ms, RTT = 1ms
+	m = &roundTripMeasurement{receiveTime: start.Add(8 * time.Millisecond), sendTime: start.Add(7 * time.Millisecond)}
+	r.update(m)
+	assert.Equal(t, start.Add(7*time.Millisecond), r.lastMeasurementTime)
+	assert.Equal(t, 1*time.Millisecond, r.rtt)
+	assert.Equal(t, 1*time.Millisecond, r.rttMin)
+	assert.Equal(t, 3*time.Millisecond, r.rttMax)
+
+	// send at -4 ms, receive at 0 ms, RTT = 4ms, but this ping is before last measurement
+	// so it will be discarded
+	m = &roundTripMeasurement{receiveTime: start, sendTime: start.Add(-2 * time.Millisecond)}
+	r.update(m)
+	assert.Equal(t, start.Add(7*time.Millisecond), r.lastMeasurementTime)
+	assert.Equal(t, 1*time.Millisecond, r.rtt)
+	assert.Equal(t, 1*time.Millisecond, r.rttMin)
+	assert.Equal(t, 3*time.Millisecond, r.rttMax)
+}
+
+func TestFlowControlDataUpdate(t *testing.T) {
+	f := newFlowControlData()
+	assert.Equal(t, 0, f.queue.Len())
+	assert.Equal(t, float64(0), f.ave())
+
+	var sum uint64
+	min := maxWindowSize - dataPoints
+	max := maxWindowSize
+	for i := 1; i <= dataPoints; i++ {
+		size := maxWindowSize - uint32(i)
+		f.update(size)
+		assert.Equal(t, max-uint32(1), f.max)
+		assert.Equal(t, size, f.min)
+
+		assert.Equal(t, i, f.queue.Len())
+
+		sum += uint64(size)
+		assert.Equal(t, sum, f.sum)
+		assert.Equal(t, ave(sum, f.queue.Len()), f.ave())
+	}
+
+	// queue is full, should start to dequeue first element
+	for i := 1; i <= dataPoints; i++ {
+		f.update(max)
+		assert.Equal(t, max, f.max)
+		assert.Equal(t, min, f.min)
+
+		assert.Equal(t, dataPoints, f.queue.Len())
+
+		sum += uint64(i)
+		assert.Equal(t, sum, f.sum)
+		assert.Equal(t, ave(sum, dataPoints), f.ave())
+	}
+}
+
+func TestMuxMetricsUpdater(t *testing.T) {
+	t.Skip("Race condition")
+	updateRTTChan := make(chan *roundTripMeasurement)
+	updateReceiveWindowChan := make(chan uint32)
+	updateSendWindowChan := make(chan uint32)
+	updateInBoundBytesChan := make(chan uint64)
+	updateOutBoundBytesChan := make(chan uint64)
+	abortChan := make(chan struct{})
+	errChan := make(chan error)
+	compBefore, compAfter := NewAtomicCounter(0), NewAtomicCounter(0)
+	m := newMuxMetricsUpdater(updateRTTChan,
+		updateReceiveWindowChan,
+		updateSendWindowChan,
+		updateInBoundBytesChan,
+		updateOutBoundBytesChan,
+		abortChan,
+		compBefore,
+		compAfter,
+	)
+	logger := log.NewEntry(log.New())
+
+	go func() {
+		errChan <- m.run(logger)
+	}()
+
+	var wg sync.WaitGroup
+	wg.Add(2)
+
+	// mock muxReader
+	readerStart := time.Now()
+	rm := &roundTripMeasurement{receiveTime: readerStart, sendTime: readerStart}
+	updateRTTChan <- rm
+	go func() {
+		defer wg.Done()
+		// Becareful if dataPoints is not divisibile by 4
+		readerSend := readerStart.Add(time.Millisecond)
+		for i := 1; i <= dataPoints/4; i++ {
+			readerReceive := readerSend.Add(time.Duration(i) * time.Millisecond)
+			rm := &roundTripMeasurement{receiveTime: readerReceive, sendTime: readerSend}
+			updateRTTChan <- rm
+			readerSend = readerReceive.Add(time.Millisecond)
+
+			updateReceiveWindowChan <- uint32(i)
+			updateSendWindowChan <- uint32(i)
+
+			updateInBoundBytesChan <- uint64(i)
+		}
+	}()
+
+	// mock muxWriter
+	go func() {
+		defer wg.Done()
+		for j := dataPoints/4 + 1; j <= dataPoints/2; j++ {
+			updateReceiveWindowChan <- uint32(j)
+			updateSendWindowChan <- uint32(j)
+
+			// should always be disgard since the send time is before readerSend
+			rm := &roundTripMeasurement{receiveTime: readerStart, sendTime: readerStart.Add(-time.Duration(j*dataPoints) * time.Millisecond)}
+			updateRTTChan <- rm
+
+			updateOutBoundBytesChan <- uint64(j)
+		}
+
+	}()
+	wg.Wait()
+
+	metrics := m.Metrics()
+	points := dataPoints / 2
+	assert.Equal(t, time.Millisecond, metrics.RTTMin)
+	assert.Equal(t, time.Duration(dataPoints/4)*time.Millisecond, metrics.RTTMax)
+
+	// sum(1..i) = i*(i+1)/2, ave(1..i) = i*(i+1)/2/i = (i+1)/2
+	assert.Equal(t, float64(points+1)/float64(2), metrics.ReceiveWindowAve)
+	assert.Equal(t, uint32(1), metrics.ReceiveWindowMin)
+	assert.Equal(t, uint32(points), metrics.ReceiveWindowMax)
+
+	assert.Equal(t, float64(points+1)/float64(2), metrics.SendWindowAve)
+	assert.Equal(t, uint32(1), metrics.SendWindowMin)
+	assert.Equal(t, uint32(points), metrics.SendWindowMax)
+
+	assert.Equal(t, uint64(dataPoints/4), metrics.InBoundRateCurr)
+	assert.Equal(t, uint64(1), metrics.InBoundRateMin)
+	assert.Equal(t, uint64(dataPoints/4), metrics.InBoundRateMax)
+
+	assert.Equal(t, uint64(dataPoints/2), metrics.OutBoundRateCurr)
+	assert.Equal(t, uint64(dataPoints/4+1), metrics.OutBoundRateMin)
+	assert.Equal(t, uint64(dataPoints/2), metrics.OutBoundRateMax)
+
+	close(abortChan)
+	assert.Nil(t, <-errChan)
+	close(errChan)
+
+}

h2mux/muxreader.go

@@ -0,0 +1,497 @@
+package h2mux
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+	"net/url"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/net/http2"
+)
+
+type MuxReader struct {
+	// f is used to read HTTP2 frames.
+	f *http2.Framer
+	// handler provides a callback to receive new streams. if nil, new streams cannot be accepted.
+	handler MuxedStreamHandler
+	// streams tracks currently-open streams.
+	streams *activeStreamMap
+	// readyList is used to signal writable streams.
+	readyList *ReadyList
+	// streamErrors lets us report stream errors to the MuxWriter.
+	streamErrors *StreamErrorMap
+	// goAwayChan is used to tell the writer to send a GOAWAY message.
+	goAwayChan chan<- http2.ErrCode
+	// abortChan is used when shutting down ungracefully. When this becomes readable, all activity should stop.
+	abortChan <-chan struct{}
+	// pingTimestamp is an atomic value containing the latest received ping timestamp.
+	pingTimestamp *PingTimestamp
+	// connActive is used to signal to the writer that something happened on the connection.
+	// This is used to clear idle timeout disconnection deadlines.
+	connActive Signal
+	// The initial value for the send and receive window of a new stream.
+	initialStreamWindow uint32
+	// The max value for the send window of a stream.
+	streamWindowMax uint32
+	// r is a reference to the underlying connection used when shutting down.
+	r io.Closer
+	// updateRTTChan is the channel to send new RTT measurement to muxerMetricsUpdater
+	updateRTTChan chan<- *roundTripMeasurement
+	// updateReceiveWindowChan is the channel to update receiveWindow size to muxerMetricsUpdater
+	updateReceiveWindowChan chan<- uint32
+	// updateSendWindowChan is the channel to update sendWindow size to muxerMetricsUpdater
+	updateSendWindowChan chan<- uint32
+	// bytesRead is the amount of bytes read from data frame since the last time we send bytes read to metrics
+	bytesRead *AtomicCounter
+	// updateOutBoundBytesChan is the channel to send bytesWrote to muxerMetricsUpdater
+	updateInBoundBytesChan chan<- uint64
+	// dictionaries holds the h2 cross-stream compression dictionaries
+	dictionaries h2Dictionaries
+}
+
+func (r *MuxReader) Shutdown() {
+	done := r.streams.Shutdown()
+	if done == nil {
+		return
+	}
+	r.sendGoAway(http2.ErrCodeNo)
+	go func() {
+		// close reader side when last stream ends; this will cause the writer to abort
+		<-done
+		r.r.Close()
+	}()
+}
+
+func (r *MuxReader) run(parentLogger *log.Entry) error {
+	logger := parentLogger.WithFields(log.Fields{
+		"subsystem": "mux",
+		"dir":       "read",
+	})
+	defer logger.Debug("event loop finished")
+
+	// routine to periodically update bytesRead
+	go func() {
+		tickC := time.Tick(updateFreq)
+		for {
+			select {
+			case <-r.abortChan:
+				return
+			case <-tickC:
+				r.updateInBoundBytesChan <- r.bytesRead.Count()
+			}
+		}
+	}()
+
+	for {
+		frame, err := r.f.ReadFrame()
+		if err != nil {
+			switch e := err.(type) {
+			case http2.StreamError:
+				logger.WithError(err).Warn("stream error")
+				r.streamError(e.StreamID, e.Code)
+			case http2.ConnectionError:
+				logger.WithError(err).Warn("connection error")
+				return r.connectionError(err)
+			default:
+				if isConnectionClosedError(err) {
+					if r.streams.Len() == 0 {
+						logger.Debug("shutting down")
+						return nil
+					}
+					logger.Warn("connection closed unexpectedly")
+					return err
+				} else {
+					logger.WithError(err).Warn("frame read error")
+					return r.connectionError(err)
+				}
+			}
+		}
+		r.connActive.Signal()
+		logger.WithField("data", frame).Debug("read frame")
+		switch f := frame.(type) {
+		case *http2.DataFrame:
+			err = r.receiveFrameData(f, logger)
+		case *http2.MetaHeadersFrame:
+			err = r.receiveHeaderData(f)
+		case *http2.RSTStreamFrame:
+			streamID := f.Header().StreamID
+			if streamID == 0 {
+				return ErrInvalidStream
+			}
+			r.streams.Delete(streamID)
+		case *http2.PingFrame:
+			r.receivePingData(f)
+		case *http2.GoAwayFrame:
+			err = r.receiveGoAway(f)
+		// The receiver of a flow-controlled frame sends a WINDOW_UPDATE frame as it
+		// consumes data and frees up space in flow-control windows
+		case *http2.WindowUpdateFrame:
+			err = r.updateStreamWindow(f)
+		case *http2.UnknownFrame:
+			switch f.Header().Type {
+			case FrameUseDictionary:
+				err = r.receiveUseDictionary(f)
+			case FrameSetDictionary:
+				err = r.receiveSetDictionary(f)
+			default:
+				err = ErrUnexpectedFrameType
+			}
+		default:
+			err = ErrUnexpectedFrameType
+		}
+		if err != nil {
+			logger.WithField("data", frame).WithError(err).Debug("frame error")
+			return r.connectionError(err)
+		}
+	}
+}
+
+func (r *MuxReader) newMuxedStream(streamID uint32) *MuxedStream {
+	return &MuxedStream{
+		streamID:                streamID,
+		readBuffer:              NewSharedBuffer(),
+		writeBuffer:             &bytes.Buffer{},
+		receiveWindow:           r.initialStreamWindow,
+		receiveWindowCurrentMax: r.initialStreamWindow,
+		receiveWindowMax:        r.streamWindowMax,
+		sendWindow:              r.initialStreamWindow,
+		readyList:               r.readyList,
+		dictionaries:            r.dictionaries,
+	}
+}
+
+// getStreamForFrame returns a stream if valid, or an error describing why the stream could not be returned.
+func (r *MuxReader) getStreamForFrame(frame http2.Frame) (*MuxedStream, error) {
+	sid := frame.Header().StreamID
+	if sid == 0 {
+		return nil, ErrUnexpectedFrameType
+	}
+	if stream, ok := r.streams.Get(sid); ok {
+		return stream, nil
+	}
+	if r.streams.IsLocalStreamID(sid) {
+		// no stream available, but no error
+		return nil, ErrClosedStream
+	}
+	if sid < r.streams.LastPeerStreamID() {
+		// no stream available, stream closed error
+		return nil, ErrClosedStream
+	}
+	return nil, ErrUnknownStream
+}
+
+func (r *MuxReader) defaultStreamErrorHandler(err error, header http2.FrameHeader) error {
+	if header.Flags.Has(http2.FlagHeadersEndStream) {
+		return nil
+	} else if err == ErrUnknownStream || err == ErrClosedStream {
+		return r.streamError(header.StreamID, http2.ErrCodeStreamClosed)
+	} else {
+		return err
+	}
+}
+
+// Receives header frames from a stream. A non-nil error is a connection error.
+func (r *MuxReader) receiveHeaderData(frame *http2.MetaHeadersFrame) error {
+	var stream *MuxedStream
+	sid := frame.Header().StreamID
+	if sid == 0 {
+		return ErrUnexpectedFrameType
+	}
+	newStream := r.streams.IsPeerStreamID(sid)
+	if newStream {
+		// header request
+		// TODO support trailers (if stream exists)
+		ok, err := r.streams.AcquirePeerID(sid)
+		if !ok {
+			// ignore new streams while shutting down
+			return r.streamError(sid, err)
+		}
+		stream = r.newMuxedStream(sid)
+		// Set stream. Returns false if a stream already existed with that ID or we are shutting down, return false.
+		if !r.streams.Set(stream) {
+			// got HEADERS frame for an existing stream
+			// TODO support trailers
+			return r.streamError(sid, http2.ErrCodeInternal)
+		}
+	} else {
+		// header response
+		var err error
+		if stream, err = r.getStreamForFrame(frame); err != nil {
+			return r.defaultStreamErrorHandler(err, frame.Header())
+		}
+	}
+	headers := make([]Header, 0, len(frame.Fields))
+	for _, header := range frame.Fields {
+		switch header.Name {
+		case ":method":
+			stream.method = header.Value
+		case ":path":
+			u, err := url.Parse(header.Value)
+			if err == nil {
+				stream.path = u.Path
+			}
+		case "accept-encoding":
+			// remove accept-encoding if dictionaries are enabled
+			if r.dictionaries.write != nil {
+				continue
+			}
+		}
+		headers = append(headers, Header{Name: header.Name, Value: header.Value})
+	}
+	stream.Headers = headers
+	if frame.Header().Flags.Has(http2.FlagHeadersEndStream) {
+		stream.receiveEOF()
+		return nil
+	}
+	if newStream {
+		go r.handleStream(stream)
+	} else {
+		close(stream.responseHeadersReceived)
+	}
+	return nil
+}
+
+func (r *MuxReader) handleStream(stream *MuxedStream) {
+	defer stream.Close()
+	r.handler.ServeStream(stream)
+}
+
+// Receives a data frame from a stream. A non-nil error is a connection error.
+func (r *MuxReader) receiveFrameData(frame *http2.DataFrame, parentLogger *log.Entry) error {
+	logger := parentLogger.WithField("stream", frame.Header().StreamID)
+	stream, err := r.getStreamForFrame(frame)
+	if err != nil {
+		return r.defaultStreamErrorHandler(err, frame.Header())
+	}
+	data := frame.Data()
+	if len(data) > 0 {
+		n, err := stream.readBuffer.Write(data)
+		if err != nil {
+			return r.streamError(stream.streamID, http2.ErrCodeInternal)
+		}
+		r.bytesRead.IncrementBy(uint64(n))
+	}
+	if frame.Header().Flags.Has(http2.FlagDataEndStream) {
+		if stream.receiveEOF() {
+			r.streams.Delete(stream.streamID)
+			logger.Debug("stream closed")
+		} else {
+			logger.Debug("shutdown receive side")
+		}
+		return nil
+	}
+	if !stream.consumeReceiveWindow(uint32(len(data))) {
+		return r.streamError(stream.streamID, http2.ErrCodeFlowControl)
+	}
+	r.updateReceiveWindowChan <- stream.getReceiveWindow()
+	return nil
+}
+
+// Receive a PING from the peer. Update RTT and send/receive window metrics if it's an ACK.
+func (r *MuxReader) receivePingData(frame *http2.PingFrame) {
+	ts := int64(binary.LittleEndian.Uint64(frame.Data[:]))
+	if !frame.IsAck() {
+		r.pingTimestamp.Set(ts)
+		return
+	}
+
+	// Update updates the computed values with a new measurement.
+	// outgoingTime is the time that the probe was sent.
+	// We assume that time.Now() is the time we received that probe.
+	r.updateRTTChan <- &roundTripMeasurement{
+		receiveTime: time.Now(),
+		sendTime:    time.Unix(0, ts),
+	}
+}
+
+// Receive a GOAWAY from the peer. Gracefully shut down our connection.
+func (r *MuxReader) receiveGoAway(frame *http2.GoAwayFrame) error {
+	r.Shutdown()
+	// Close all streams above the last processed stream
+	lastStream := r.streams.LastLocalStreamID()
+	for i := frame.LastStreamID + 2; i <= lastStream; i++ {
+		if stream, ok := r.streams.Get(i); ok {
+			stream.Close()
+		}
+	}
+	return nil
+}
+
+// Receive a USE_DICTIONARY from the peer. Setup dictionary for stream.
+func (r *MuxReader) receiveUseDictionary(frame *http2.UnknownFrame) error {
+	payload := frame.Payload()
+	streamID := frame.StreamID
+
+	// Check frame is formatted properly
+	if len(payload) != 1 {
+		return r.streamError(streamID, http2.ErrCodeProtocol)
+	}
+
+	stream, err := r.getStreamForFrame(frame)
+	if err != nil {
+		return err
+	}
+
+	if stream.receivedUseDict == true || stream.dictionaries.read == nil {
+		return r.streamError(streamID, http2.ErrCodeInternal)
+	}
+
+	stream.receivedUseDict = true
+	dictID := payload[0]
+
+	dictReader := stream.dictionaries.read.newReader(stream.readBuffer.(*SharedBuffer), dictID)
+	if dictReader == nil {
+		return r.streamError(streamID, http2.ErrCodeInternal)
+	}
+
+	stream.readBufferLock.Lock()
+	stream.readBuffer = dictReader
+	stream.readBufferLock.Unlock()
+
+	return nil
+}
+
+// Receive a SET_DICTIONARY from the peer. Update dictionaries accordingly.
+func (r *MuxReader) receiveSetDictionary(frame *http2.UnknownFrame) (err error) {
+
+	payload := frame.Payload()
+	flags := frame.Flags
+
+	stream, err := r.getStreamForFrame(frame)
+	if err != nil && err != ErrClosedStream {
+		return err
+	}
+	reader, ok := stream.readBuffer.(*h2DictionaryReader)
+	if !ok {
+		return r.streamError(frame.StreamID, http2.ErrCodeProtocol)
+	}
+
+	// A SetDictionary frame consists of several
+	// Dictionary-Entries that specify how existing dictionaries
+	// are to be updated using the current stream data
+	// +---------------+---------------+
+	// |   Dictionary-Entry (+)    ...
+	// +---------------+---------------+
+
+	for {
+		// Each Dictionary-Entry is formatted as follows:
+		// +-------------------------------+
+		// |       Dictionary-ID (8)       |
+		// +---+---------------------------+
+		// | P |        Size (7+)          |
+		// +---+---------------------------+
+		// | E?| D?|  Truncate? (6+)       |
+		// +---+---------------------------+
+		// |           Offset? (8+)        |
+		// +-------------------------------+
+
+		var size, truncate, offset uint64
+		var p, e, d bool
+
+		// Parse a single Dictionary-Entry
+		if len(payload) < 2 { // Must have at least id and size
+			return MuxerStreamError{"unexpected EOF", http2.ErrCodeProtocol}
+		}
+
+		dictID := uint8(payload[0])
+		p = (uint8(payload[1]) >> 7) == 1
+		payload, size, err = http2ReadVarInt(7, payload[1:])
+		if err != nil {
+			return
+		}
+
+		if flags.Has(FlagSetDictionaryAppend) {
+			// Presence of FlagSetDictionaryAppend means we expect e, d and truncate
+			if len(payload) < 1 {
+				return MuxerStreamError{"unexpected EOF", http2.ErrCodeProtocol}
+			}
+			e = (uint8(payload[0]) >> 7) == 1
+			d = (uint8((payload[0])>>6) & 1) == 1
+			payload, truncate, err = http2ReadVarInt(6, payload)
+			if err != nil {
+				return
+			}
+		}
+
+		if flags.Has(FlagSetDictionaryOffset) {
+			// Presence of FlagSetDictionaryOffset means we expect offset
+			if len(payload) < 1 {
+				return MuxerStreamError{"unexpected EOF", http2.ErrCodeProtocol}
+			}
+			payload, offset, err = http2ReadVarInt(8, payload)
+			if err != nil {
+				return
+			}
+		}
+
+		setdict := setDictRequest{streamID: stream.streamID,
+			dictID:   dictID,
+			dictSZ:   size,
+			truncate: truncate,
+			offset:   offset,
+			P:        p,
+			E:        e,
+			D:        d}
+
+		// Find the right dictionary
+		dict, err := r.dictionaries.read.getDictByID(dictID)
+		if err != nil {
+			return err
+		}
+
+		// Register a dictionary update order for the dictionary and reader
+		updateEntry := &dictUpdate{reader: reader, dictionary: dict, s: setdict}
+		dict.queue = append(dict.queue, updateEntry)
+		reader.queue = append(reader.queue, updateEntry)
+		// End of frame
+		if len(payload) == 0 {
+			break
+		}
+	}
+	return nil
+}
+
+// Receives header frames from a stream. A non-nil error is a connection error.
+func (r *MuxReader) updateStreamWindow(frame *http2.WindowUpdateFrame) error {
+	stream, err := r.getStreamForFrame(frame)
+	if err != nil && err != ErrUnknownStream && err != ErrClosedStream {
+		return err
+	}
+	if stream == nil {
+		// ignore window updates on closed streams
+		return nil
+	}
+	stream.replenishSendWindow(frame.Increment)
+	r.updateSendWindowChan <- stream.getSendWindow()
+	return nil
+}
+
+// Raise a stream processing error, closing the stream. Runs on the write thread.
+func (r *MuxReader) streamError(streamID uint32, e http2.ErrCode) error {
+	r.streamErrors.RaiseError(streamID, e)
+	return nil
+}
+
+func (r *MuxReader) connectionError(err error) error {
+	http2Code := http2.ErrCodeInternal
+	switch e := err.(type) {
+	case http2.ConnectionError:
+		http2Code = http2.ErrCode(e)
+	case MuxerProtocolError:
+		http2Code = e.h2code
+	}
+	r.sendGoAway(http2Code)
+	return err
+}
+
+// Instruct the writer to send a GOAWAY message if possible. This may fail in
+// the case where an existing GOAWAY message is in flight or the writer event
+// loop already ended.
+func (r *MuxReader) sendGoAway(errCode http2.ErrCode) {
+	select {
+	case r.goAwayChan <- errCode:
+	default:
+	}
+}

h2mux/muxwriter.go

@@ -0,0 +1,287 @@
+package h2mux
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/hpack"
+)
+
+type MuxWriter struct {
+	// f is used to write HTTP2 frames.
+	f *http2.Framer
+	// streams tracks currently-open streams.
+	streams *activeStreamMap
+	// streamErrors receives stream errors raised by the MuxReader.
+	streamErrors *StreamErrorMap
+	// readyStreamChan is used to multiplex writable streams onto the single connection.
+	// When a stream becomes writable its ID is sent on this channel.
+	readyStreamChan <-chan uint32
+	// newStreamChan is used to create new streams with a given set of headers.
+	newStreamChan <-chan MuxedStreamRequest
+	// goAwayChan is used to send a single GOAWAY message to the peer. The element received
+	// is the HTTP/2 error code to send.
+	goAwayChan <-chan http2.ErrCode
+	// abortChan is used when shutting down ungracefully. When this becomes readable, all activity should stop.
+	abortChan <-chan struct{}
+	// pingTimestamp is an atomic value containing the latest received ping timestamp.
+	pingTimestamp *PingTimestamp
+	// A timer used to measure idle connection time. Reset after sending data.
+	idleTimer *IdleTimer
+	// connActiveChan receives a signal that the connection received some (read) activity.
+	connActiveChan <-chan struct{}
+	// Maximum size of all frames that can be sent on this connection.
+	maxFrameSize uint32
+	// headerEncoder is the stateful header encoder for this connection
+	headerEncoder *hpack.Encoder
+	// headerBuffer is the temporary buffer used by headerEncoder.
+	headerBuffer bytes.Buffer
+	// updateReceiveWindowChan is the channel to update receiveWindow size to muxerMetricsUpdater
+	updateReceiveWindowChan chan<- uint32
+	// updateSendWindowChan is the channel to update sendWindow size to muxerMetricsUpdater
+	updateSendWindowChan chan<- uint32
+	// bytesWrote is the amount of bytes wrote to data frame since the last time we send bytes wrote to metrics
+	bytesWrote *AtomicCounter
+	// updateOutBoundBytesChan is the channel to send bytesWrote to muxerMetricsUpdater
+	updateOutBoundBytesChan chan<- uint64
+
+	useDictChan <-chan useDictRequest
+}
+
+type MuxedStreamRequest struct {
+	stream *MuxedStream
+	body   io.Reader
+}
+
+func (r *MuxedStreamRequest) flushBody() {
+	io.Copy(r.stream, r.body)
+	r.stream.CloseWrite()
+}
+
+func tsToPingData(ts int64) [8]byte {
+	pingData := [8]byte{}
+	binary.LittleEndian.PutUint64(pingData[:], uint64(ts))
+	return pingData
+}
+
+func (w *MuxWriter) run(parentLogger *log.Entry) error {
+	logger := parentLogger.WithFields(log.Fields{
+		"subsystem": "mux",
+		"dir":       "write",
+	})
+	defer logger.Debug("event loop finished")
+
+	// routine to periodically communicate bytesWrote
+	go func() {
+		tickC := time.Tick(updateFreq)
+		for {
+			select {
+			case <-w.abortChan:
+				return
+			case <-tickC:
+				w.updateOutBoundBytesChan <- w.bytesWrote.Count()
+			}
+		}
+	}()
+
+	for {
+		select {
+		case <-w.abortChan:
+			logger.Debug("aborting writer thread")
+			return nil
+		case errCode := <-w.goAwayChan:
+			logger.Debug("sending GOAWAY code ", errCode)
+			err := w.f.WriteGoAway(w.streams.LastPeerStreamID(), errCode, []byte{})
+			if err != nil {
+				return err
+			}
+			w.idleTimer.MarkActive()
+		case <-w.pingTimestamp.GetUpdateChan():
+			logger.Debug("sending PING ACK")
+			err := w.f.WritePing(true, tsToPingData(w.pingTimestamp.Get()))
+			if err != nil {
+				return err
+			}
+			w.idleTimer.MarkActive()
+		case <-w.idleTimer.C:
+			if !w.idleTimer.Retry() {
+				return ErrConnectionDropped
+			}
+			logger.Debug("sending PING")
+			err := w.f.WritePing(false, tsToPingData(time.Now().UnixNano()))
+			if err != nil {
+				return err
+			}
+			w.idleTimer.ResetTimer()
+		case <-w.connActiveChan:
+			w.idleTimer.MarkActive()
+		case <-w.streamErrors.GetSignalChan():
+			for streamID, errCode := range w.streamErrors.GetErrors() {
+				logger.WithField("stream", streamID).WithField("code", errCode).Debug("resetting stream")
+				err := w.f.WriteRSTStream(streamID, errCode)
+				if err != nil {
+					return err
+				}
+			}
+			w.idleTimer.MarkActive()
+		case streamRequest := <-w.newStreamChan:
+			streamID := w.streams.AcquireLocalID()
+			streamRequest.stream.streamID = streamID
+			if !w.streams.Set(streamRequest.stream) {
+				// Race between OpenStream and Shutdown, and Shutdown won. Let Shutdown (and the eventual abort) take
+				// care of this stream. Ideally we'd pass the error directly to the stream object somehow so the
+				// caller can be unblocked sooner, but the value of that optimisation is minimal for most of the
+				// reasons why you'd call Shutdown anyway.
+				continue
+			}
+			if streamRequest.body != nil {
+				go streamRequest.flushBody()
+			}
+			streamLogger := logger.WithField("stream", streamID)
+			err := w.writeStreamData(streamRequest.stream, streamLogger)
+			if err != nil {
+				return err
+			}
+			w.idleTimer.MarkActive()
+		case streamID := <-w.readyStreamChan:
+			streamLogger := logger.WithField("stream", streamID)
+			stream, ok := w.streams.Get(streamID)
+			if !ok {
+				continue
+			}
+			err := w.writeStreamData(stream, streamLogger)
+			if err != nil {
+				return err
+			}
+			w.idleTimer.MarkActive()
+		case useDict := <-w.useDictChan:
+			err := w.writeUseDictionary(useDict)
+			if err != nil {
+				logger.WithError(err).Warn("error writing use dictionary")
+				return err
+			}
+			w.idleTimer.MarkActive()
+		}
+	}
+}
+
+func (w *MuxWriter) writeStreamData(stream *MuxedStream, logger *log.Entry) error {
+	logger.Debug("writable")
+	chunk := stream.getChunk()
+	w.updateReceiveWindowChan <- stream.getReceiveWindow()
+	w.updateSendWindowChan <- stream.getSendWindow()
+	if chunk.sendHeadersFrame() {
+		err := w.writeHeaders(chunk.streamID, chunk.headers)
+		if err != nil {
+			logger.WithError(err).Warn("error writing headers")
+			return err
+		}
+		logger.Debug("output headers")
+	}
+
+	if chunk.sendWindowUpdateFrame() {
+		// Send a WINDOW_UPDATE frame to update our receive window.
+		// If the Stream ID is zero, the window update applies to the connection as a whole
+		// RFC7540 section-6.9.1 "A receiver that receives a flow-controlled frame MUST
+		// always account for  its contribution against the connection flow-control
+		// window, unless the receiver treats this as a connection error"
+		err := w.f.WriteWindowUpdate(chunk.streamID, chunk.windowUpdate)
+		if err != nil {
+			logger.WithError(err).Warn("error writing window update")
+			return err
+		}
+		logger.Debugf("increment receive window by %d", chunk.windowUpdate)
+	}
+
+	for chunk.sendDataFrame() {
+		payload, sentEOF := chunk.nextDataFrame(int(w.maxFrameSize))
+		err := w.f.WriteData(chunk.streamID, sentEOF, payload)
+		if err != nil {
+			logger.WithError(err).Warn("error writing data")
+			return err
+		}
+		// update the amount of data wrote
+		w.bytesWrote.IncrementBy(uint64(len(payload)))
+		logger.WithField("len", len(payload)).Debug("output data")
+
+		if sentEOF {
+			if stream.readBuffer.Closed() {
+				// transition into closed state
+				if !stream.gotReceiveEOF() {
+					// the peer may send data that we no longer want to receive. Force them into the
+					// closed state.
+					logger.Debug("resetting stream")
+					w.f.WriteRSTStream(chunk.streamID, http2.ErrCodeNo)
+				} else {
+					// Half-open stream transitioned into closed
+					logger.Debug("closing stream")
+				}
+				w.streams.Delete(chunk.streamID)
+			} else {
+				logger.Debug("closing stream write side")
+			}
+		}
+	}
+	return nil
+}
+
+func (w *MuxWriter) encodeHeaders(headers []Header) ([]byte, error) {
+	w.headerBuffer.Reset()
+	for _, header := range headers {
+		err := w.headerEncoder.WriteField(hpack.HeaderField{
+			Name:  header.Name,
+			Value: header.Value,
+		})
+		if err != nil {
+			return nil, err
+		}
+	}
+	return w.headerBuffer.Bytes(), nil
+}
+
+// writeHeaders writes a block of encoded headers, splitting it into multiple frames if necessary.
+func (w *MuxWriter) writeHeaders(streamID uint32, headers []Header) error {
+	encodedHeaders, err := w.encodeHeaders(headers)
+	if err != nil {
+		return err
+	}
+	blockSize := int(w.maxFrameSize)
+	endHeaders := len(encodedHeaders) == 0
+	for !endHeaders && err == nil {
+		blockFragment := encodedHeaders
+		if len(encodedHeaders) > blockSize {
+			blockFragment = blockFragment[:blockSize]
+			encodedHeaders = encodedHeaders[blockSize:]
+			// Send CONTINUATION frame if the headers can't be fit into 1 frame
+			err = w.f.WriteContinuation(streamID, endHeaders, blockFragment)
+		} else {
+			endHeaders = true
+			err = w.f.WriteHeaders(http2.HeadersFrameParam{
+				StreamID:      streamID,
+				EndHeaders:    endHeaders,
+				BlockFragment: blockFragment,
+			})
+		}
+	}
+	return err
+}
+
+func (w *MuxWriter) writeUseDictionary(dictRequest useDictRequest) error {
+	err := w.f.WriteRawFrame(FrameUseDictionary, 0, dictRequest.streamID, []byte{byte(dictRequest.dictID)})
+	if err != nil {
+		return err
+	}
+	payload := make([]byte, 0, 64)
+	for _, set := range dictRequest.setDict {
+		payload = append(payload, byte(set.dictID))
+		payload = appendVarInt(payload, 7, uint64(set.dictSZ))
+		payload = append(payload, 0x80) // E = 1, D = 0, Truncate = 0
+	}
+
+	err = w.f.WriteRawFrame(FrameSetDictionary, FlagSetDictionaryAppend, dictRequest.streamID, payload)
+	return err
+}

h2mux/readylist.go

@@ -0,0 +1,140 @@
+package h2mux
+
+// ReadyList multiplexes several event signals onto a single channel.
+type ReadyList struct {
+	signalC chan uint32
+	waitC   chan uint32
+}
+
+func NewReadyList() *ReadyList {
+	rl := &ReadyList{
+		signalC: make(chan uint32),
+		waitC:   make(chan uint32),
+	}
+	go rl.run()
+	return rl
+}
+
+// ID is the stream ID
+func (r *ReadyList) Signal(ID uint32) {
+	r.signalC <- ID
+}
+
+func (r *ReadyList) ReadyChannel() <-chan uint32 {
+	return r.waitC
+}
+
+func (r *ReadyList) Close() {
+	close(r.signalC)
+}
+
+func (r *ReadyList) run() {
+	defer close(r.waitC)
+	var queue readyDescriptorQueue
+	var firstReady *readyDescriptor
+	activeDescriptors := newReadyDescriptorMap()
+	for {
+		if firstReady == nil {
+			// Wait for first ready descriptor
+			i, ok := <-r.signalC
+			if !ok {
+				// closed
+				return
+			}
+			firstReady = activeDescriptors.SetIfMissing(i)
+		}
+		select {
+		case r.waitC <- firstReady.ID:
+			activeDescriptors.Delete(firstReady.ID)
+			firstReady = queue.Dequeue()
+		case i, ok := <-r.signalC:
+			if !ok {
+				// closed
+				return
+			}
+			newReady := activeDescriptors.SetIfMissing(i)
+			if newReady != nil {
+				// key doesn't exist
+				queue.Enqueue(newReady)
+			}
+		}
+	}
+}
+
+type readyDescriptor struct {
+	ID   uint32
+	Next *readyDescriptor
+}
+
+// readyDescriptorQueue is a queue of readyDescriptors in the form of a singly-linked list.
+// The nil readyDescriptorQueue is an empty queue ready for use.
+type readyDescriptorQueue struct {
+	Head *readyDescriptor
+	Tail *readyDescriptor
+}
+
+func (q *readyDescriptorQueue) Empty() bool {
+	return q.Head == nil
+}
+
+func (q *readyDescriptorQueue) Enqueue(x *readyDescriptor) {
+	if x.Next != nil {
+		panic("enqueued already queued item")
+	}
+	if q.Empty() {
+		q.Head = x
+		q.Tail = x
+	} else {
+		q.Tail.Next = x
+		q.Tail = x
+	}
+}
+
+// Dequeue returns the first readyDescriptor in the queue, or nil if empty.
+func (q *readyDescriptorQueue) Dequeue() *readyDescriptor {
+	if q.Empty() {
+		return nil
+	}
+	x := q.Head
+	q.Head = x.Next
+	x.Next = nil
+	return x
+}
+
+// readyDescriptorQueue is a map of readyDescriptors keyed by ID.
+// It maintains a free list of deleted ready descriptors.
+type readyDescriptorMap struct {
+	descriptors map[uint32]*readyDescriptor
+	free        []*readyDescriptor
+}
+
+func newReadyDescriptorMap() *readyDescriptorMap {
+	return &readyDescriptorMap{descriptors: make(map[uint32]*readyDescriptor)}
+}
+
+// create or reuse a readyDescriptor if the stream is not in the queue.
+// This avoid stream starvation caused by a single high-bandwidth stream monopolising the writer goroutine
+func (m *readyDescriptorMap) SetIfMissing(key uint32) *readyDescriptor {
+	if _, ok := m.descriptors[key]; ok {
+		return nil
+	}
+
+	var newDescriptor *readyDescriptor
+	if len(m.free) > 0 {
+		// reuse deleted ready descriptors
+		newDescriptor = m.free[len(m.free)-1]
+		m.free = m.free[:len(m.free)-1]
+	} else {
+		newDescriptor = &readyDescriptor{}
+	}
+	newDescriptor.ID = key
+	m.descriptors[key] = newDescriptor
+	return newDescriptor
+}
+
+func (m *readyDescriptorMap) Delete(key uint32) {
+	if descriptor, ok := m.descriptors[key]; ok {
+		m.free = append(m.free, descriptor)
+		delete(m.descriptors, key)
+	}
+}

h2mux/readylist_test.go

@@ -0,0 +1,115 @@
+package h2mux
+
+import (
+	"testing"
+	"time"
+)
+
+func TestReadyList(t *testing.T) {
+	rl := NewReadyList()
+	c := rl.ReadyChannel()
+	// helper functions
+	assertEmpty := func() {
+		select {
+		case <-c:
+			t.Fatalf("Spurious wakeup")
+		default:
+		}
+	}
+	receiveWithTimeout := func() uint32 {
+		select {
+		case i := <-c:
+			return i
+		case <-time.After(100 * time.Millisecond):
+			t.Fatalf("Timeout")
+			return 0
+		}
+	}
+	// no signals, receive should fail
+	assertEmpty()
+	rl.Signal(0)
+	if receiveWithTimeout() != 0 {
+		t.Fatalf("Received wrong ID of signalled event")
+	}
+	// no new signals, receive should fail
+	assertEmpty()
+	// Signals should not block;
+	// Duplicate unhandled signals should not cause multiple wakeups
+	signalled := [5]bool{}
+	for i := range signalled {
+		rl.Signal(uint32(i))
+		rl.Signal(uint32(i))
+	}
+	// All signals should be received once (in any order)
+	for range signalled {
+		i := receiveWithTimeout()
+		if signalled[i] {
+			t.Fatalf("Received signal %d more than once", i)
+		}
+		signalled[i] = true
+	}
+}
+
+func TestReadyDescriptorQueue(t *testing.T) {
+	var queue readyDescriptorQueue
+	items := [4]readyDescriptor{}
+	for i := range items {
+		items[i].ID = uint32(i)
+	}
+
+	if !queue.Empty() {
+		t.Fatalf("nil queue should be empty")
+	}
+	queue.Enqueue(&items[3])
+	queue.Enqueue(&items[1])
+	queue.Enqueue(&items[0])
+	queue.Enqueue(&items[2])
+	if queue.Empty() {
+		t.Fatalf("Empty should be false after enqueue")
+	}
+	i := queue.Dequeue().ID
+	if i != 3 {
+		t.Fatalf("item 3 should have been dequeued, got %d instead", i)
+	}
+	i = queue.Dequeue().ID
+	if i != 1 {
+		t.Fatalf("item 1 should have been dequeued, got %d instead", i)
+	}
+	i = queue.Dequeue().ID
+	if i != 0 {
+		t.Fatalf("item 0 should have been dequeued, got %d instead", i)
+	}
+	i = queue.Dequeue().ID
+	if i != 2 {
+		t.Fatalf("item 2 should have been dequeued, got %d instead", i)
+	}
+	if !queue.Empty() {
+		t.Fatal("queue should be empty after dequeuing all items")
+	}
+	if queue.Dequeue() != nil {
+		t.Fatal("dequeue on empty queue should return nil")
+	}
+}
+
+func TestReadyDescriptorMap(t *testing.T) {
+	m := newReadyDescriptorMap()
+	m.Delete(42)
+	// (delete of missing key should be a noop)
+	x := m.SetIfMissing(42)
+	if x == nil {
+		t.Fatal("SetIfMissing for new key returned nil")
+	}
+	if m.SetIfMissing(42) != nil {
+		t.Fatal("SetIfMissing for existing key returned non-nil")
+	}
+	// this delete has effect
+	m.Delete(42)
+	// the next set should reuse the old object
+	y := m.SetIfMissing(666)
+	if y == nil {
+		t.Fatal("SetIfMissing for new key returned nil")
+	}
+	if x != y {
+		t.Fatal("SetIfMissing didn't reuse freed object")
+	}
+}

h2mux/rtt.go

@@ -0,0 +1,29 @@
+package h2mux
+
+import (
+	"sync/atomic"
+)
+
+// PingTimestamp is an atomic interface around ping timestamping and signalling.
+type PingTimestamp struct {
+	ts     int64
+	signal Signal
+}
+
+func NewPingTimestamp() *PingTimestamp {
+	return &PingTimestamp{signal: NewSignal()}
+}
+
+func (pt *PingTimestamp) Set(v int64) {
+	if atomic.SwapInt64(&pt.ts, v) != 0 {
+		pt.signal.Signal()
+	}
+}
+
+func (pt *PingTimestamp) Get() int64 {
+	return atomic.SwapInt64(&pt.ts, 0)
+}
+
+func (pt *PingTimestamp) GetUpdateChan() <-chan struct{} {
+	return pt.signal.WaitChannel()
+}

h2mux/sample/ghost-url.min.js

@@ -0,0 +1 @@
+!function(){"use strict";function a(a){var b,c=[];if(!a)return"";for(b in a)a.hasOwnProperty(b)&&(a[b]||a[b]===!1)&&c.push(b+"="+encodeURIComponent(a[b]));return c.length?"?"+c.join("&"):""}var b,c,d,e,f="https://cloudflare.ghost.io/ghost/api/v0.1/";d={api:function(){var d,e=Array.prototype.slice.call(arguments),g=f;return d=e.pop(),d&&"object"!=typeof d&&(e.push(d),d={}),d=d||{},d.client_id=b,d.client_secret=c,e.length&&e.forEach(function(a){g+=a.replace(/^\/|\/$/g,"")+"/"}),g+a(d)}},e=function(a){b=a.clientId?a.clientId:"",c=a.clientSecret?a.clientSecret:"",f=a.url?a.url:f.match(/{\{api-url}}/)?"":f},"undefined"!=typeof window&&(window.ghost=window.ghost||{},window.ghost.url=d,window.ghost.init=e),"undefined"!=typeof module&&(module.exports={url:d,init:e})}();

h2mux/sample/index.html

@@ -0,0 +1,537 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8" />
+    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
+
+    <title>Cloudflare Blog</title>
+    <meta name="description" content="" />
+    <meta name="HandheldFriendly" content="True">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <meta name="msvalidate.01" content="CF295E1604697F9CAD18B5A232E871F6" />
+
+    <link rel="shortcut icon" href="/assets/images/favicon.ico?v=b6cf3f99a6">
+    <link rel="apple-touch-icon-precomposed" sizes="57x57" href="/assets/images/apple-touch-icon-57x57-precomposed.png?v=b6cf3f99a6" />
+    <link rel="apple-touch-icon-precomposed" sizes="72x72" href="/assets/images/apple-touch-icon-72x72-precomposed.png?v=b6cf3f99a6" />
+    <link rel="apple-touch-icon-precomposed" sizes="114x114" href="/assets/images/apple-touch-icon-114x114-precomposed.png?v=b6cf3f99a6" />
+    <link rel="apple-touch-icon-precomposed" sizes="144x144" href="/assets/images/apple-touch-icon-144x144-precomposed.png?v=b6cf3f99a6" />
+
+    <link rel="stylesheet" type="text/css" href="/assets/css/screen.css?v=b6cf3f99a6" />
+    <!--[if lt IE 9]><link rel="stylesheet" type="text/css" href="/assets/css/ie.css?v=b6cf3f99a6" /><![endif]-->
+
+    <!--<link href="http://fonts.googleapis.com/css?family=Open+Sans:300italic,400italic,600italic,700italic,400,700,300,600" rel="stylesheet" type="text/css">-->
+
+    <script>(function(G,o,O,g,l){G.GoogleAnalyticsObject=O;G[O]||(G[O]=function(){(G[O].q=G[O].q||[]).push(arguments)});G[O].l=+new Date;g=o.createElement('script'),l=o.scripts[0];g.src='//www.google-analytics.com/analytics.js';l.parentNode.insertBefore(g,l)}(this,document,'ga'));ga('create','UA-10218544-12', 'auto');ga('send','pageview')</script>
+
+    <link rel="canonical" href="http://blog.cloudflare.com/" />
+    <meta name="referrer" content="no-referrer-when-downgrade" />
+    <link rel="next" href="https://blog.cloudflare.com/page/2/" />
+    
+    <meta property="og:site_name" content="Cloudflare Blog" />
+    <meta property="og:type" content="website" />
+    <meta property="og:title" content="Cloudflare Blog" />
+    <meta property="og:url" content="http://blog.cloudflare.com/" />
+    <meta property="og:image" content="http://blog.cloudflare.com/content/images/2016/09/logo-for-blog_thumb-1.png" />
+    <meta property="article:publisher" content="https://www.facebook.com/Cloudflare" />
+    <meta name="twitter:card" content="summary_large_image" />
+    <meta name="twitter:title" content="Cloudflare Blog" />
+    <meta name="twitter:url" content="http://blog.cloudflare.com/" />
+    <meta name="twitter:image" content="http://blog.cloudflare.com/content/images/2016/09/logo-for-blog_thumb-1.png" />
+    <meta name="twitter:site" content="@cloudflare" />
+    <meta property="og:image:width" content="189" />
+    <meta property="og:image:height" content="47" />
+    
+    <script type="application/ld+json">
+{
+    "@context": "https://schema.org",
+    "@type": "Website",
+    "publisher": {
+        "@type": "Organization",
+        "name": "Cloudflare Blog",
+        "logo": {
+            "@type": "ImageObject",
+            "url": "http://blog.cloudflare.com/content/images/2016/09/logo-for-blog_thumb.png",
+            "width": 189,
+            "height": 47
+        }
+    },
+    "url": "https://blog.cloudflare.com/",
+    "image": {
+        "@type": "ImageObject",
+        "url": "http://blog.cloudflare.com/content/images/2016/09/logo-for-blog_thumb-1.png",
+        "width": 189,
+        "height": 47
+    },
+    "mainEntityOfPage": {
+        "@type": "WebPage",
+        "@id": "http://blog.cloudflare.com"
+    }
+}
+    </script>
+
+    <script type="text/javascript" src="/shared/ghost-url.min.js?v=b6cf3f99a6"></script>
+<script type="text/javascript">
+ghost.init({
+	clientId: "ghost-frontend",
+	clientSecret: "cf0df60d1ab4"
+});
+</script>
+    <meta name="generator" content="Ghost 0.11" />
+    <link rel="alternate" type="application/rss+xml" title="Cloudflare Blog" href="https://blog.cloudflare.com/rss/" />
+    <meta name="msvalidate.01" content="CF295E1604697F9CAD18B5A232E871F6" />
+<meta class="swiftype" name="language" data-type="string" content="en" />
+<script src="https://s3-us-west-1.amazonaws.com/cf-ghost-assets-hotfix/js/index.js"></script>
+<script type="text/javascript" src="//cdn.bizible.com/scripts/bizible.js" async=""></script>
+<script>
+var trackRecruitingLink = function(role, url) {
+   ga('send', 'event', 'recruiting', 'jobscore-click', role, {
+     'transport': 'beacon',
+     'hitCallback': function(){document.location = url;}
+   });
+}
+</script> 
+<script type="text/javascript">
+	(function() {
+		var didInit = false;
+		function initMunchkin() {
+			if(didInit === false) {
+				didInit = true;
+				Munchkin.init('713-XSC-918');
+			}
+		}
+		var s = document.createElement('script');
+		s.type = 'text/javascript';
+		s.async = true;
+		s.src = '//munchkin.marketo.net/munchkin.js';
+		s.onreadystatechange = function() {
+			if (this.readyState == 'complete' || this.readyState == 'loaded') {
+				initMunchkin();
+			}
+		};
+		s.onload = initMunchkin;
+		document.getElementsByTagName('head')[0].appendChild(s);
+		})();
+</script>
+<script>
+var HTMLAttrToAdd = document.querySelector("html");
+HTMLAttrToAdd.setAttribute("lang", "en");
+</script>
+<style>
+    table {
+        background-color: transparent;
+    }
+    td {
+		padding: 5px 1em;
+    }
+    pre {
+        max-height: 500px;
+        overflow-y: scroll;
+    }
+</style>
+<link href="https://s3-us-west-1.amazonaws.com/cf-ghost-assets-hotfix/css/screen.css" rel="stylesheet">
+<link href="https://cdnjs.cloudflare.com/ajax/libs/prism/1.8.1/themes/prism.min.css" rel="stylesheet">
+
+    <style>
+        .st-default-search-input {
+            font-family: Helvetica, Arial, "Lucida Grande", sans-serif;
+            font-size: 14px;
+            line-height: 16px;
+            font-weight: 400;
+            -moz-transition: opacity 0.2s;
+            -o-transition: opacity 0.2s;
+            -webkit-transition: opacity 0.2s;
+            transition: opacity 0.2s;
+            display: inline-block;
+            width: 190px;
+            height: 16px;
+            padding: 7px 11px 7px 28px;
+            border: 1px solid rgba(0, 0, 0, 0.25);
+            color: #444;
+            -moz-box-sizing: content-box;
+            box-sizing: content-box;
+            -moz-border-radius: 5px;
+            -webkit-border-radius: 5px;
+            border-radius: 5px;
+            background: #fff 8px 8px no-repeat url("data:image/png;base64, iVBORw0KGgoAAAANSUhEUgAAAA0AAAANCAYAAABy6%2BR8AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAIGNIUk0AAG11AABzoAAA%2FN0AAINkAABw6AAA7GgAADA%2BAAAQkOTsmeoAAAESSURBVHjajNCxS9VRGMbxz71E4OwgoXPQxVEpXCI47%2BZqGP0LCoJO7UVD3QZzb3SwcHB7F3Uw3Zpd%2FAPCcJKG7Dj4u%2FK7Pwp94HDg5Xyf5z1Pr9YKImKANTzFXxzjU2ae6qhXaxURr%2FAFl9hHDy%2FwEK8z89sYVEp5gh84wMvMvGiSJ%2FEV85jNzLMR1McqfmN5BEBmnmMJFSvtpH7jdJiZv7q7Z%2BZPfMdcF6rN%2FT%2F1m2LGBkd4HhFT3dcRMY2FpskxaLNpayciHrWAGeziD7b%2BVfkithuTk8bkGa4wgWFmbrSTZOYeBvjc%2BucQj%2FEe6xHx4Taq1nrnKaW8K6XUUsrHWuvNevdRRLzFGwzvDbXAB9cDAHvhedDruuxSAAAAAElFTkSuQmCC")
+        }
+
+        .st-ui-close-button {
+            -moz-transition: none;
+            -o-transition: none;
+            -webkit-transition: none;
+            transition: none
+        }
+    </style>
+</head>
+<body class="home-template">
+<div id="fb-root"></div>
+<header id="header" class="header">
+    <div class="wrapper">
+        <a href="https://www.cloudflare.com" class="logo logo-header">Cloudflare</a>
+        <nav id="main-menu" class="header-navigation navigation" role="navigation">
+            <ul class="menu menu-header">
+                <li><a href="https://blog.cloudflare.com/">Blog home</a></li>
+                <li><a href="https://www.cloudflare.com/overview" tabindex="1">What we do</a></li>
+                <li><a href="https://www.cloudflare.com/support" tabindex="9">Support</a></li>
+                <li><a href="https://www.cloudflare.com/community" tabindex="9">Community</a></li>
+                <li><a href="https://www.cloudflare.com/login" tabindex="10">Login</a></li>
+                <li><a href="https://www.cloudflare.com/sign-up" class="btn btn-success" tabindex="11">Sign up</a></li>
+            </ul>
+        </nav>
+    </div>
+</header>
+
+<div class="wrapper reverse-sidebar">
+    <section class="primary-content" role="main">
+
+        
+
+<article class="post tag-google-cloud tag-cloud-computing tag-internet-summit">
+    <header class="post-header">
+        <h2 class="title"><a href="/living-in-a-multi-cloud-world/">Living In A Multi-Cloud World</a></h2>
+        <div class="meta">
+            Published on <time class="meta-date" datetime="November 21st, 2017 4:30PM">November 21st, 2017 4:30PM</time>
+            by <a href="/author/sergi/">Sergi Isasi</a>.
+        </div>
+    </header>
+    <div class="post-excerpt">
+        <p>A few months ago at Cloudflare’s Internet Summit, we hosted a discussion on A Cloud Without Handcuffs with Joe Beda, one of the creators of Kubernetes, and Brandon Phillips, the co-founder of CoreOS. The conversation touched on multiple areas, but it’s clear that more and more companies are recognizing the need to have some strategy around hosting their applications on multiple cloud providers. Earlier this year,&hellip;</p>
+    </div>
+    <footer>
+        <a href="/living-in-a-multi-cloud-world/" class="more">Read more &raquo; </a><br>
+        <small>
+            <span class="post-meta">
+                <a href="/living-in-a-multi-cloud-world/#disqus_thread">Comments</a> | tagged with <a href="/tag/google-cloud/">Google Cloud</a>, <a href="/tag/cloud-computing/">Cloud Computing</a>, <a href="/tag/internet-summit/">Internet Summit</a>
+            </span>
+        </small>
+    </footer>
+</article>
+
+
+
+<article class="post tag-legal tag-jengo tag-patents">
+    <header class="post-header">
+        <h2 class="title"><a href="/supreme-court-wanders-into-patent-troll-fight/">The Supreme Court Wanders into the Patent Troll Fight</a></h2>
+        <div class="meta">
+            Published on <time class="meta-date" datetime="November 20th, 2017 6:18PM">November 20th, 2017 6:18PM</time>
+            by <a href="/author/edo-royker/">Edo Royker</a>.
+        </div>
+    </header>
+    <div class="post-excerpt">
+        <p>Next Monday, the US Supreme Court will hear oral arguments in Oil States Energy Services, LLC vs. Greene’s Energy Group, LLC, which is a case to determine whether the Inter Partes Review (IPR) administrative process at the US Patent and Trademark Office (USPTO) used to determine the validity of patents is constitutional.  The constitutionality of the IPR process is one of the biggest legal issues facing innovative&hellip;</p>
+    </div>
+    <footer>
+        <a href="/supreme-court-wanders-into-patent-troll-fight/" class="more">Read more &raquo; </a><br>
+        <small>
+            <span class="post-meta">
+                <a href="/supreme-court-wanders-into-patent-troll-fight/#disqus_thread">Comments</a> | tagged with <a href="/tag/legal/">Legal</a>, <a href="/tag/jengo/">Jengo</a>, <a href="/tag/patents/">Patents</a>
+            </span>
+        </small>
+    </footer>
+</article>
+
+
+
+<article class="post tag-cloudflare-apps tag-developers tag-user-engagement">
+    <header class="post-header">
+        <h2 class="title"><a href="/7cloudflareappsengagement/">7 Cloudflare Apps Which Increase User Engagement on Your Site</a></h2>
+        <div class="meta">
+            Published on <time class="meta-date" datetime="November 14th, 2017 8:21PM">November 14th, 2017 8:21PM</time>
+            by <a href="/author/andrew/">Andrew Fitch</a>.
+        </div>
+    </header>
+    <div class="post-excerpt">
+        <p>Cloudflare Apps now lists 95 apps  from apps which grow email lists to apps which acquire new customers to apps which help site owners make more money. The great thing about these apps is that users don't have to have any coding or development skills. They can just sign up for the app and start using it on their sites.   Let’s take a moment to highlight some&hellip;</p>
+    </div>
+    <footer>
+        <a href="/7cloudflareappsengagement/" class="more">Read more &raquo; </a><br>
+        <small>
+            <span class="post-meta">
+                <a href="/7cloudflareappsengagement/#disqus_thread">Comments</a> | tagged with <a href="/tag/cloudflare-apps/">Cloudflare Apps</a>, <a href="/tag/developers/">Developers</a>, <a href="/tag/user-engagement/">User Engagement</a>
+            </span>
+        </small>
+    </footer>
+</article>
+
+
+
+<article class="post tag-acquisitions tag-cloudflare-team tag-mobile tag-neumob">
+    <header class="post-header">
+        <h2 class="title"><a href="/neumob-optimizing-mobile/">The Super Secret Cloudflare Master Plan, or why we acquired Neumob</a></h2>
+        <div class="meta">
+            Published on <time class="meta-date" datetime="November 14th, 2017 2:00PM">November 14th, 2017 2:00PM</time>
+            by <a href="/author/john-graham-cumming/">John Graham-Cumming</a>.
+        </div>
+    </header>
+    <div class="post-excerpt">
+        <p>We announced today that Cloudflare has acquired Neumob. Neumob’s team built exceptional technology to speed up mobile apps, reduce errors on challenging mobile networks, and increase conversions. Cloudflare will integrate the Neumob technology with our global network to give Neumob truly global reach.  It’s tempting to think of the Neumob acquisition as a point product added to the Cloudflare portfolio. But it actually represents a key&hellip;</p>
+    </div>
+    <footer>
+        <a href="/neumob-optimizing-mobile/" class="more">Read more &raquo; </a><br>
+        <small>
+            <span class="post-meta">
+                <a href="/neumob-optimizing-mobile/#disqus_thread">Comments</a> | tagged with <a href="/tag/acquisitions/">Acquisitions</a>, <a href="/tag/cloudflare-team/">Cloudflare Team</a>, <a href="/tag/mobile/">Mobile</a>, <a href="/tag/neumob/">Neumob</a>
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+        </small>
+    </footer>
+</article>
+
+
+
+<article class="post tag-security tag-legal tag-privacy tag-attacks">
+    <header class="post-header">
+        <h2 class="title"><a href="/thwarting-the-tactics-of-the-equifax-attackers/">Thwarting the Tactics of the Equifax Attackers</a></h2>
+        <div class="meta">
+            Published on <time class="meta-date" datetime="November 13th, 2017 4:09PM">November 13th, 2017 4:09PM</time>
+            by <a href="/author/alex-cruz-farmer/">Alex Cruz Farmer</a>.
+        </div>
+    </header>
+    <div class="post-excerpt">
+        <p>We are now 3 months on from one of the biggest, most significant data breaches in history, but has it redefined people's awareness on security? The answer to that is absolutely yes, awareness is at an all-time high. Awareness, however, does not always result in positive action. The fallacy which is often assumed is "surely, if I keep my software up to date with all the patches, that's&hellip;</p>
+    </div>
+    <footer>
+        <a href="/thwarting-the-tactics-of-the-equifax-attackers/" class="more">Read more &raquo; </a><br>
+        <small>
+            <span class="post-meta">
+                <a href="/thwarting-the-tactics-of-the-equifax-attackers/#disqus_thread">Comments</a> | tagged with <a href="/tag/security/">Security</a>, <a href="/tag/legal/">Legal</a>, <a href="/tag/privacy/">Privacy</a>, <a href="/tag/attacks/">Attacks</a>
+            </span>
+        </small>
+    </footer>
+</article>
+
+
+
+<article class="post tag-go tag-performance tag-golang tag-developers">
+    <header class="post-header">
+        <h2 class="title"><a href="/go-dont-collect-my-garbage/">Go, don&#x27;t collect my garbage</a></h2>
+        <div class="meta">
+            Published on <time class="meta-date" datetime="November 13th, 2017 10:31AM">November 13th, 2017 10:31AM</time>
+            by <a href="/author/vlad-krasnov/">Vlad Krasnov</a>.
+        </div>
+    </header>
+    <div class="post-excerpt">
+        <p>Not long ago I needed to benchmark the performance of Golang on a many-core machine. I took several of the benchmarks that are bundled with the Go source code, copied them, and modified them to run on all available threads. In that case the machine has 24 cores and 48 threads. CC BY-SA 2.0 image by sponki25 I started with ECDSA P256 Sign, probably because I have&hellip;</p>
+    </div>
+    <footer>
+        <a href="/go-dont-collect-my-garbage/" class="more">Read more &raquo; </a><br>
+        <small>
+            <span class="post-meta">
+                <a href="/go-dont-collect-my-garbage/#disqus_thread">Comments</a> | tagged with <a href="/tag/go/">Go</a>, <a href="/tag/performance/">Performance</a>, <a href="/tag/golang/">golang</a>, <a href="/tag/developers/">Developers</a>
+            </span>
+        </small>
+    </footer>
+</article>
+
+
+
+<article class="post tag-developers tag-javascript tag-php tag-lua tag-go tag-meetup tag-cloudflare-meetups tag-community tag-pizza">
+    <header class="post-header">
+        <h2 class="title"><a href="/cloudflare-wants-to-buy-your-meetup-group-pizza/">Cloudflare Wants to Buy Your Meetup Group Pizza</a></h2>
+        <div class="meta">
+            Published on <time class="meta-date" datetime="November 10th, 2017 3:00PM">November 10th, 2017 3:00PM</time>
+            by <a href="/author/andrew/">Andrew Fitch</a>.
+        </div>
+    </header>
+    <div class="post-excerpt">
+        <p>If you’re a web dev / devops / etc. meetup group that also works toward building a faster, safer Internet, I want to support your awesome group by buying you pizza. If your group’s focus falls within one of the subject categories below and you’re willing to give us a 30 second shout out and tweet a photo of your group and @Cloudflare, your meetup’s pizza&hellip;</p>
+    </div>
+    <footer>
+        <a href="/cloudflare-wants-to-buy-your-meetup-group-pizza/" class="more">Read more &raquo; </a><br>
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+                <a href="/cloudflare-wants-to-buy-your-meetup-group-pizza/#disqus_thread">Comments</a> | tagged with <a href="/tag/developers/">Developers</a>, <a href="/tag/javascript/">javascript</a>, <a href="/tag/php/">php</a>, <a href="/tag/lua/">lua</a>, <a href="/tag/go/">Go</a>, <a href="/tag/meetup/">MeetUp</a>, <a href="/tag/cloudflare-meetups/">Cloudflare Meetups</a>, <a href="/tag/community/">Community</a>, <a href="/tag/pizza/">Pizza</a>
+            </span>
+        </small>
+    </footer>
+</article>
+
+
+
+<article class="post">
+    <header class="post-header">
+        <h2 class="title"><a href="/on-the-dangers-of-intels-frequency-scaling/">On the dangers of Intel&#x27;s frequency scaling</a></h2>
+        <div class="meta">
+            Published on <time class="meta-date" datetime="November 10th, 2017 11:06AM">November 10th, 2017 11:06AM</time>
+            by <a href="/author/vlad-krasnov/">Vlad Krasnov</a>.
+        </div>
+    </header>
+    <div class="post-excerpt">
+        <p>While I was writing the post comparing the new Qualcomm server chip, Centriq, to our current stock of Intel Skylake-based Xeons, I noticed a disturbing phenomena. When benchmarking OpenSSL 1.1.1dev, I discovered that the performance of the cipher ChaCha20-Poly1305 does not scale very well. On a single thread, it performed at the speed of approximately 2.89GB/s, whereas on 24 cores, and 48 threads it&hellip;</p>
+    </div>
+    <footer>
+        <a href="/on-the-dangers-of-intels-frequency-scaling/" class="more">Read more &raquo; </a><br>
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+        <article class="post tag-google-cloud tag-cloud-computing tag-internet-summit">
+
+
+        <header class="post-header">
+            <h1 class="title">Living In A Multi-Cloud World</h1>
+            <div class="meta">
+                <time class="meta-date" datetime="2017-11-21">21 Nov 2017</time>
+                by <a href="/author/sergi/">Sergi Isasi</a>.
+            </div>
+            <div class="social">
+                <div class="g-plusone" data-size="medium" data-href="https://blog.cloudflare.com/living-in-a-multi-cloud-world/"></div>
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+                <a href="https://twitter.com/share" class="twitter-share-button" data-url="https://blog.cloudflare.com/living-in-a-multi-cloud-world/" data-text="Living In A Multi-Cloud World" data-via="cloudflare" data-related="cloudflare">Tweet</a>
+            </div>
+        </header>
+
+        <div class="post-content">
+            <p>A few months ago at Cloudflare’s <a href="https://www.cloudflare.com/internet-summit/">Internet Summit</a>, we hosted a discussion on <a href="https://blog.cloudflare.com/a-cloud-without-handcuffs/">A Cloud Without Handcuffs</a> with Joe Beda, one of the creators of Kubernetes, and Brandon Phillips, the co-founder of CoreOS. The conversation touched on multiple areas, but it’s clear that more and more companies are recognizing the need to have some strategy around hosting their applications on multiple cloud providers.</p>
+
+<p>Earlier this year, Mary Meeker published her annual <a href="http://www.kpcb.com/internet-trends">Internet Trends</a> report which revealed that 22% of respondents viewed Cloud Vendor Lock-In as a top 3 concern, up from just 7% in 2012. This is in contrast to previous top concerns, Data Security and Cost &amp; Savings, both of which dropped amongst those surveyed.</p>
+
+<p><img src="/content/images/2017/11/Mary-Meeker-Internet-Trends-2017.png" alt="Internet Trends" /></p>
+
+<p>At Cloudflare, our mission is to help build a better internet. To fulfill this mission, our customers need to have consistent access to the best technology and services, over time. This is especially the case with respect to storage and compute providers. This means not becoming locked-in to any single provider and taking advantage of multiple cloud computing vendors (such as Amazon Web Services or Google Cloud Platform) for the same end user services. </p>
+
+<h3 id="thebenefitsofhavingmultiplecloudvendors">The Benefits of Having Multiple Cloud Vendors</h3>
+
+<p>There are a number of potential challenges when selecting a single cloud provider. Though there may be scenarios where it makes sense to consolidate on a single vendor, our belief is that it is important that customers are aware of their choice and downsides of being potentially locked-in to that particular vendor. In short, know what trade offs you are making should you decide to continue to consolidate parts of your network, compute, and storage with a single cloud provider. While not comprehensive, here are a few trade-offs you may be making if you are locked-in to one cloud.</p>
+
+<h4 id="costefficiences">Cost Efficiences</h4>
+
+<p>For some companies, there may be a cost savings involved in spreading traffic across multiple vendors. Some can take advantage of free or reduced cost tiers at lower volumes. Vendors may provide reduced costs for certain times of day that are lower utilized on their infrastructure. Applications can have varying compute requirements amongst layers of the application: some may require faster, immediate processing while others may benefit from delayed processing at a lower cost. </p>
+
+<h4 id="negotiationstrength">Negotiation Strength</h4>
+
+<p>One of the most important reasons to consider deploying in multiple cloud providers is to minimize your reliance on a single vendor’s technology for your critical business processes. As you become more vertically integrated with any vendor, your negotiation posture for pricing or favorable contract terms becomes diminished. Having production ready code available on multiple providers allows you to have less technical debt should you need to change. If you go a step further and are already sending traffic to multiple providers, you have minimized the technical debt required to switch and can negotiate from a position of strength.</p>
+
+<h4 id="businesscontinuityorhighavailability">Business Continuity or High Availability</h4>
+
+<p>While the major cloud providers are generally reliable, there have been a few notable outages in recent years. The most significant in recent memory being Amazon’s <a href="https://aws.amazon.com/message/41926/">US-EAST S3</a> outage in February. Some organizations may have a policy specifying multiple providers for high availability while others should consider it where necessary and feasible as a best practice. A multi-cloud strategy can lower operational risk from a single vendor’s mistakes causing a significant outage for a mission critical application.</p>
+
+<h4 id="experimentation">Experimentation</h4>
+
+<p>One of the exciting things about having competition in the space is the level of innovation and feature velocity of each provider. Every year there are major announcements of new products or features that may have a significant impact on improving your organization's competitive advantage. Having test and production environments in multiple providers gives your engineers the ability to understand and experiment with a new capability in the context of your technology stack and data. You may even try these features for a portion of your traffic and get real world data on any benefits realized.</p>
+
+<h3 id="cloudflaresrole">Cloudflare’s Role</h3>
+
+<p>Cloudflare is an independent third party in your multi-cloud strategy. Our goal is to minimize the layers of lock-in between you and a provider and lower the effort of change. In particular, one area where we can help right away is to minimize the operational changes necessary at the network, similar to what Kubernetes can do at the storage and compute level. As a benefit of our network, you can also have a centralized point for security and operational control.</p>
+
+<p><img src="/content/images/2017/11/Cloudflare_Multi_Cloud.png" alt="Cloudflare Multi Cloud" /></p>
+
+<p>Cloudflare’s Load Balancing can easily be configured to act as your global application traffic aggregator and distribute your traffic amongst origins at as many clouds as you choose to utilize. Active layer 7 health checks continually probe your origins and can automatically move traffic in the case of network or application failure. All consolidated web traffic can be inspected and acted upon by Cloudflare’s best of breed <a href="https://www.cloudflare.com/security/">Security</a> services, providing a single control point and visibility across all application traffic, regardless of which cloud the origin may be on. You also have the benefit of Cloudflare’s <a href="https://www.cloudflare.com/network/">Global Anycast Network</a>, providing for better speed and higher availability regardless of which clouds your origins are hosted on.</p>
+
+<h3 id="billforwardusingcloudflaretoimplementmulticloud">Billforward: Using Cloudflare to Implement Multi-Cloud</h3>
+
+<p>Billforward is a San Francisco and London based startup that is focused and mission driven on changing the way people bill and charge their customers, providing a solution to the complexities of Quote-to-Cash. Their platform is built on a number of Rest APIs that other developers call to bill and generate revenue for their own companies.  </p>
+
+<p>Billforward is using Cloudflare for its core customer facing application to failover traffic between Google Compute Engine and Amazon Web Services. Acting as a reverse proxy, Cloudflare receives all requests for and decides which of Billforward’s two configured cloud origins to use based upon the availability of that origin in near real-time. This allows Billforward to completely manage the connections to and from two disparate cloud providers using Cloudflare’s UI or API. Billforward is in the process of migrating all of their customer facing domains to a similar setup.</p>
+
+<h4 id="configuration">Configuration</h4>
+
+<p>Billforward has a single load balanced hostname with two available Pools. They’ve named the two Pools with “gce” and “aws” labels and each Pool has one Origin associated with it. All of the Pools are enabled and the entire LB/hostname is proxied through Cloudflare (as indicated by the orange cloud).</p>
+
+<p><img src="/content/images/2017/11/Billforward_Config_UI.png" alt="Billforward Configuration UI" /></p>
+
+<p>Cloudflare probes Billforward’s Origins once every minute from all of Cloudflare’s data centers around the world (a feature available to all Load Balancing Enterprise customers). If Billforward’s GCE Origin goes down, Cloudflare will quickly and automatically failover to the AWS Origin with no actions required from Billforward’s team.</p>
+
+<p>Google Compute Engine was chosen as the primary provider for this application by virtue of cost. Martin Lee, Site Reliability Engineer at Billforward says, “Essentially, GCE is cheaper for our general purpose computing needs but we're more experienced with deployments in AWS. This strategy allows us to switch back and forth at will and avoid being tied in to either platform.” It is likely that Billforward will change the priority as pricing models evolve. <br />
+<br>  </p>
+
+<blockquote>
+  <p>“It's a fairly fast moving world and features released by cloud providers can have a meaningful impact on performance and cost on a week by week basis - it helps to stay flexible,” says Martin. “We may also change priority based on features.”</p>
+</blockquote>
+
+<p><br>For orchestration of the compute and storage layers, Billforward uses <a href="https://www.docker.com/">Docker</a> containers managed through <a href="http://www.rancher.com/">Rancher</a>. They use distinct environments between cloud providers but are considering bridging an environment across cloud providers and using VPNs between them, which will enable them to move load between providers even more easily. “Our system is loosely coupled through a message queue,” adds Martin. “Having a container system across clouds means we can really take advantage of this - we can very easily move workloads across clouds without any danger of dropping tasks or ending up in an inconsistent state.”</p>
+
+<h4 id="benefits">Benefits</h4>
+
+<p>Billforward manages these connections at Cloudflare’s edge. Through this interface (or via the Cloudflare APIs), they can also manually move traffic from GCE to AWS by just disabling the GCE pool or by rearranging the Pool priority and make AWS the primary. These changes are near instant on the Cloudflare network and require no downtime to Billforward’s customer facing application. This allows them to act on potential advantageous pricing changes between the two cloud providers or move traffic to hit pricing tiers. </p>
+
+<p>In addition, Billforward is now not “locked-in” to either provider’s network; being able to move traffic and without any downtime means they can make traffic changes independent of Amazon or Google. They can also integrate additional cloud providers any time they deem fit: adding Microsoft Azure, for example, as a third Origin would be as simple as creating a new Pool and adding it to the Load Balancer. </p>
+
+<p>Billforward is a good example of a forward thinking company that is taking advantage of technologies from multiple providers to best serve their business and customers, while not being reliant on a single vendor. For further detail on their setup using Cloudflare, please check their <a href="https://www.billforward.net/blog/being-multi-cloud-with-cloudflare/">blog</a>.</p>
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+        <header class="post-header">
+            <h1 class="title">The Supreme Court Wanders into the Patent Troll Fight</h1>
+            <div class="meta">
+                <time class="meta-date" datetime="2017-11-20">20 Nov 2017</time>
+                by <a href="/author/edo-royker/">Edo Royker</a>.
+            </div>
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+        <div class="post-content">
+            <p>Next Monday, the US Supreme Court will hear oral arguments in <em>Oil States Energy Services, LLC vs. Greene’s Energy Group, LLC</em>, which is a case to determine whether the Inter Partes Review (IPR) administrative process at the US Patent and Trademark Office (USPTO) used to determine the validity of patents is constitutional. </p>
+
+<p>The constitutionality of the IPR process is one of the biggest legal issues facing innovative technology companies, as the availability of this process has greatly reduced the anticipated costs, and thereby lessened the threat, of patent troll litigation. As we discuss in this blog post, it is ironic that the outcome of a case that is of such great importance to the technology community today may hinge on what courts in Britain were and were not doing more than 200 years ago.</p>
+
+<p><img src="/content/images/2017/11/Thomas_Rowlandson_-_The_Privy_Council_of_a_King_-_Google_Art_Project.jpg" alt="" title="" /><small>Thomas Rowlandson [Public domain], via <a href="https://commons.wikimedia.org/wiki/File%3AThomas_Rowlandson_-_The_Privy_Council_of_a_King_-_Google_Art_Project.jpg">Wikimedia Commons</a></small></p>
+
+<p>As we have discussed in prior <a href="https://blog.cloudflare.com/project-jengo-challenges/">blog posts</a>, the stakes are high: if the Supreme Court finds IPR unconstitutional, then the entire system of administrative review by the USPTO — including IPR and ex parte processes — will be shuttered.  This would be a mistake, as administrative recourse at the USPTO is one of the few ways to avoid the considerable costs and delays of federal court litigation, which can take years and run into the millions of dollars. Those heavy costs are often leveraged by patent trolls when they threaten litigation in the effort to procure easy and lucrative settlements from their targets. </p>
+
+<h3 id="cloudflareispursuingourfightagainstpatenttrollsallthewaytothestepsofthesupremecourt">Cloudflare is Pursuing Our Fight Against Patent Trolls All the Way to the Steps of the Supreme Court</h3>
+
+<p>Cloudflare joined Dell, Facebook, and a number of other companies, all practicing entities with large patent portfolios, in a <em>brief amici curiae</em> (or ‘friend of the court’ brief) in support of the IPR process, because it has a substantial positive impact on technological innovation in the United States. Amicus briefs allow parties who are interested in the outcome of a case, but are not parties to the immediate dispute before the court, to have input into the court’s deliberations.  </p>
+
+<p>As many of you are aware, we were sued by Blackbird Technologies, a notorious patent troll, earlier this year for patent infringement, and initiated <a href="https://blog.cloudflare.com/project-jengo/">Project Jengo</a> to crowd source prior art searches and invalidate Blackbird’s patents. One of our strategies for quickly and efficiently invalidating Blackbird’s patents is to take advantage of the IPR process at the USPTO, which can be completed in about half the time and at one tenth of the cost of a federal court case, and to initiate ex parte proceedings against Blackbird’s other patents that are overly broad and invalid. </p>
+
+<p>A full copy of the Amicus Brief we joined in the Oil States case is <a href="http://www.scotusblog.com/wp-content/uploads/2017/11/16-712-bsac-Dell.pdf">available here</a>, and a summary of the argument follows. </p>
+
+<h3 id="oilstatesmakesitscase">Oil States Makes its Case</h3>
+
+<p>Oil States is an oilfield services and drilling equipment manufacturing company. The USPTO invalidated one of its patents related to oil drilling technology in an IPR proceeding while Oil States had a lawsuit pending against one of its competitors claiming infringement of its patent. After it lost the IPR, Oil States lost an appeal in a lower federal court based on the findings of the IPR proceeding. The Supreme Court agreed to hear the case to determine whether once the USPTO issues a patent, an inventor has a constitutionally protected property right that — under <a href="http://www.heritage.org/constitution/#!/articles/3">Article III</a> of the U.S. Constitution (which outlines the powers of the judicial branch of the government), and the <a href="https://constitutioncenter.org/interactive-constitution/amendments/amendment-vii">7th Amendment</a> (which addresses the right to a jury trial in certain types of cases) — cannot be revoked without intervention by the court system. </p>
+
+<p><img src="/content/images/2017/11/2770193028_68edc662a9_b.jpg" alt="" title="" /><small><a href="https://www.flickr.com/photos/paul_lowry/2770193028">Image</a> by <a href="https://creativecommons.org/licenses/by/2.0/">Paul Lowry</a></small></p>
+
+<p>As the patent owner, Oil States argues that the IPR process violates the relevant provisions of the constitution by allowing an administrative body, the Patent Trial and Appeal Board (PTAB)--a non-judicial forum, to decide a matter which was historically handled by the judiciary. This argument rests upon the premise that there was a historical analogue to cancellation of patent claims available in the judiciary. Since cancellation of patent claims was historically available in the judiciary, the cancellation of patent claims today must be consistent with that history and done exclusively by courts. </p>
+
+<p>This argument is flawed on multiple counts, which are set forth in the “friend of the court” brief we joined.</p>
+
+<h4 id="firstflawanadministrativeprocessevenanoriginalistcanlove">First Flaw: An Administrative Process Even an Originalist Can Love</h4>
+
+<p>As the amicus brief we joined points out, patent revocation did not historically rest within the <em>exclusive</em> province of the common law and chancery courts, the historical equivalents in Britain to the judiciary in the United States. Rather, prior to the Founding of the United States, patent revocation rested entirely with the Crown of England’s Privy Council, a non-judicial body comprising of advisors to the king or queen of England. It wasn’t until later that the Privy Council granted the chancery court (the judiciary branch) concurrent authority to revoke patents. Because a non-judicial body had the authority to revoke patents when the US Constitution was framed, the general principles of separation of powers and the right to trial in the Constitution do not require that patentability challenges be decided solely by courts. </p>
+
+<h4 id="secondflawthejudicialrolewaslimited">Second Flaw: The Judicial Role was Limited</h4>
+
+<p>Not only did British courts share the power to address patent rights historically, the part shared by the the courts was significantly limited.  Historically, the common-law and chancery courts only received a partial delegation of the Privy Council’s authority to invalidate patents. Courts only had the authority to invalidate patents for issues related to things like inequitable conduct (e.g., making false statements in the original patent application). The limited authority delegated to the England Courts did not include the authority to seek claim <em>cancellation</em> based on elements intrinsic to the patent or patent application, like lack of novelty or obviousness as done under an IPR proceeding. Rather, such authority remained with the Privy Council, a non-court authority, which decided questions like whether the invention was really new. Thus, like the PTAB, the Privy Council was a non-judicial body charged with responsibility to assess patent validity based on criteria that included the novelty of the invention.</p>
+
+<p>We think these arguments are compelling and provide very strong reasons why the Supreme Court should resist the request that such matters be resolved exclusively in federal courts. We hope that’s the position they do take because the real world implications are significant. </p>
+
+<h3 id="dontmesswithagoodthing">Don’t Mess with a Good Thing</h3>
+
+<p>The IPR process is not only consistent with the US Constitution, but it also advances the Patent Clause’s objective of promoting the progress of science and useful arts. That is, the “quid pro quo of the patent system; the public must receive meaningful disclosure in exchange for being excluded from practicing the invention for a limited period of time” by patent rights. (<a href="http://caselaw.findlaw.com/us-federal-circuit/1330083.html">Enzo Biochem, Inc. v. Gen-probe Inc.</a>) Congress created the IPR process in the America Invents Act in 2011 to use administrative review to weed out poor-quality patents that did not satisfy this quid pro quo because they had not actually disclosed very much. Congress sought to provide quick and cost effective administrative procedures for challenging the validity of patent claims that did not disclose novel inventions, or that claimed to disclose substantially more innovation than they actually did,  to improve patent quality and restore confidence in the presumption of validity. In other words, Congress created a system to specifically permit the efficient challenge of the zealous assertion of vague and overly broad patents. </p>
+
+<p>As a recent study by the Congressional Research Service found, non-practicing entity (i.e., patent troll) patent litigation “activity cost defendants and licensees $29 billion in 2011, a 400 percent increase over $7 billion in 2005” and “the losses are mostly deadweight, with less than 25 percent flowing to innovation and at least that much going towards legal fees.” (<em>see</em> <a href="https://fas.org/sgp/crs/misc/R42668.pdf">Brian T. Yeh, Cong. Research sERV., R42668</a>) The IPR process enables innovative companies to navigate patent troll activity in an efficient manner and devote a greater proportion of their resources to research and development, rather than litigation or cost-of-litigation settlement fees for invalid patents. </p>
+
+<p><img src="/content/images/2017/11/Troll-slip.jpg" alt="" title="" /><small>By EFF-Graphics (<a href="http://creativecommons.org/licenses/by/3.0/us/deed.en">Own work</a>), via <a href="https://commons.wikimedia.org/wiki/File%3ATroll-slip.jpg">Wikimedia Commons</a></small></p>
+
+<p>Additionally, the IPR process reduces the total number and associated costs of patent disputes in a number of ways.</p>
+
+<ul>
+<li><p>Patent owners, especially patent trolls, are less likely to threaten litigation or file an infringement suit based on patent claims that they know or suspect to be invalid. In fact, patent owners who threaten or file suit merely to seek cost-of-litigation settlements have become far less prevalent because of the availability of the IPR process to reduce the cost of litigation.</p></li>
+<li><p>Patent owners are less likely to initiate litigation out of concerns that the IPR proceedings may culminate in PTAB’s cancellation of all patent claims asserted in the infringement suit.</p></li>
+<li><p>Where the PTAB does not cancel all asserted claims, statutory estoppel and the PTAB’s claim construction may serve to narrow the infringement issues to be resolved by the district court.</p></li>
+</ul>
+
+<p>Our hope is that the US Supreme Court justices take into full consideration the larger community of innovative companies that are helped by the IPR system in battling patent trolls, and do not limit their consideration to the implications on the parties to <em>Oil States</em> (neither of which is a non-practicing entity). As we have explained, not only does the IPR process enable innovative companies to focus their resources on technological innovation, instead of legal fees, but allowing the USPTO to administer IPR and ex parte proceedings is entirely consistent with the US Constitution.</p>
+
+<p>While we await a decision in <em>Oil States</em>, expect to see Cloudflare initiate IPR and ex parte proceedings against Blackbird Technologies patents in the coming months. </p>
+
+<p>We will make sure to keep you updated. </p>
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+    </div>
+</footer>
+
+<script>
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+
+    for (var i = 0, linksLength = links.length; i < linksLength; i++) {  
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+           links[i].target = '_blank';
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+<script src="https://cdnjs.cloudflare.com/ajax/libs/prism/1.8.1/prism.min.js"></script>
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+<script type="text/javascript">
+    $(document).ready(function(){ $(".post-content").fitVids(); });
+</script>
+
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+
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+
+</body>
+</html>

h2mux/sample/jquery.fitvids.js

@@ -0,0 +1,74 @@
+/*global jQuery */
+/*jshint multistr:true browser:true */
+/*!
+* FitVids 1.0.3
+*
+* Copyright 2013, Chris Coyier - http://css-tricks.com + Dave Rupert - http://daverupert.com
+* Credit to Thierry Koblentz - http://www.alistapart.com/articles/creating-intrinsic-ratios-for-video/
+* Released under the WTFPL license - http://sam.zoy.org/wtfpl/
+*
+* Date: Thu Sept 01 18:00:00 2011 -0500
+*/
+
+(function( $ ){
+
+  "use strict";
+
+  $.fn.fitVids = function( options ) {
+    var settings = {
+      customSelector: null
+    };
+
+    if(!document.getElementById('fit-vids-style')) {
+
+      var div = document.createElement('div'),
+          ref = document.getElementsByTagName('base')[0] || document.getElementsByTagName('script')[0],
+          cssStyles = '&shy;<style>.fluid-width-video-wrapper{width:100%;position:relative;padding:0;}.fluid-width-video-wrapper iframe,.fluid-width-video-wrapper object,.fluid-width-video-wrapper embed {position:absolute;top:0;left:0;width:100%;height:100%;}</style>';
+
+      div.className = 'fit-vids-style';
+      div.id = 'fit-vids-style';
+      div.style.display = 'none';
+      div.innerHTML = cssStyles;
+
+      ref.parentNode.insertBefore(div,ref);
+
+    }
+
+    if ( options ) {
+      $.extend( settings, options );
+    }
+
+    return this.each(function(){
+      var selectors = [
+        "iframe[src*='player.vimeo.com']",
+        "iframe[src*='youtube.com']",
+        "iframe[src*='youtube-nocookie.com']",
+        "iframe[src*='kickstarter.com'][src*='video.html']",
+        "object",
+        "embed"
+      ];
+
+      if (settings.customSelector) {
+        selectors.push(settings.customSelector);
+      }
+
+      var $allVideos = $(this).find(selectors.join(','));
+      $allVideos = $allVideos.not("object object"); // SwfObj conflict patch
+
+      $allVideos.each(function(){
+        var $this = $(this);
+        if (this.tagName.toLowerCase() === 'embed' && $this.parent('object').length || $this.parent('.fluid-width-video-wrapper').length) { return; }
+        var height = ( this.tagName.toLowerCase() === 'object' || ($this.attr('height') && !isNaN(parseInt($this.attr('height'), 10))) ) ? parseInt($this.attr('height'), 10) : $this.height(),
+            width = !isNaN(parseInt($this.attr('width'), 10)) ? parseInt($this.attr('width'), 10) : $this.width(),
+            aspectRatio = height / width;
+        if(!$this.attr('id')){
+          var videoID = 'fitvid' + Math.floor(Math.random()*999999);
+          $this.attr('id', videoID);
+        }
+        $this.wrap('<div class="fluid-width-video-wrapper"></div>').parent('.fluid-width-video-wrapper').css('padding-top', (aspectRatio * 100)+"%");
+        $this.removeAttr('height').removeAttr('width');
+      });
+    });
+  };
+// Works with either jQuery or Zepto
+})( window.jQuery || window.Zepto );

h2mux/shared_buffer.go

@@ -0,0 +1,67 @@
+package h2mux
+
+import (
+	"bytes"
+	"io"
+	"sync"
+)
+
+type SharedBuffer struct {
+	cond   *sync.Cond
+	buffer bytes.Buffer
+	eof    bool
+}
+
+func NewSharedBuffer() *SharedBuffer {
+	return &SharedBuffer{
+		cond: sync.NewCond(&sync.Mutex{}),
+	}
+}
+
+func (s *SharedBuffer) Read(p []byte) (n int, err error) {
+	totalRead := 0
+	s.cond.L.Lock()
+	for totalRead == 0 {
+		n, err = s.buffer.Read(p[totalRead:])
+		totalRead += n
+		if err == io.EOF {
+			if s.eof {
+				break
+			}
+			err = nil
+			if n > 0 {
+				break
+			}
+			s.cond.Wait()
+		}
+	}
+	s.cond.L.Unlock()
+	return totalRead, err
+}
+
+func (s *SharedBuffer) Write(p []byte) (n int, err error) {
+	s.cond.L.Lock()
+	defer s.cond.L.Unlock()
+	if s.eof {
+		return 0, io.EOF
+	}
+	n, err = s.buffer.Write(p)
+	s.cond.Signal()
+	return
+}
+
+func (s *SharedBuffer) Close() error {
+	s.cond.L.Lock()
+	defer s.cond.L.Unlock()
+	if !s.eof {
+		s.eof = true
+		s.cond.Signal()
+	}
+	return nil
+}
+
+func (s *SharedBuffer) Closed() bool {
+	s.cond.L.Lock()
+	defer s.cond.L.Unlock()
+	return s.eof
+}

h2mux/shared_buffer_test.go

@@ -0,0 +1,127 @@
+package h2mux
+
+import (
+	"bytes"
+	"io"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func AssertIOReturnIsGood(t *testing.T, expected int) func(int, error) {
+	return func(actual int, err error) {
+		if expected != actual {
+			t.Fatalf("Expected %d bytes, got %d", expected, actual)
+		}
+		if err != nil {
+			t.Fatalf("Unexpected error %s", err)
+		}
+	}
+}
+
+func TestSharedBuffer(t *testing.T) {
+	b := NewSharedBuffer()
+	testData := []byte("Hello world")
+	AssertIOReturnIsGood(t, len(testData))(b.Write(testData))
+	bytesRead := make([]byte, len(testData))
+	AssertIOReturnIsGood(t, len(testData))(b.Read(bytesRead))
+}
+
+func TestSharedBufferBlockingRead(t *testing.T) {
+	b := NewSharedBuffer()
+	testData1 := []byte("Hello")
+	testData2 := []byte(" world")
+	result := make(chan []byte)
+	go func() {
+		bytesRead := make([]byte, len(testData1)+len(testData2))
+		nRead, err := b.Read(bytesRead)
+		AssertIOReturnIsGood(t, len(testData1))(nRead, err)
+		result <- bytesRead[:nRead]
+		nRead, err = b.Read(bytesRead)
+		AssertIOReturnIsGood(t, len(testData2))(nRead, err)
+		result <- bytesRead[:nRead]
+	}()
+	time.Sleep(time.Millisecond * 250)
+	select {
+	case <-result:
+		t.Fatalf("read returned early")
+	default:
+	}
+	AssertIOReturnIsGood(t, len(testData1))(b.Write([]byte(testData1)))
+	select {
+	case r := <-result:
+		assert.Equal(t, testData1, r)
+	case <-time.After(time.Second):
+		t.Fatalf("read timed out")
+	}
+	AssertIOReturnIsGood(t, len(testData2))(b.Write([]byte(testData2)))
+	select {
+	case r := <-result:
+		assert.Equal(t, testData2, r)
+	case <-time.After(time.Second):
+		t.Fatalf("read timed out")
+	}
+}
+
+// This is quite slow under the race detector
+func TestSharedBufferConcurrentReadWrite(t *testing.T) {
+	b := NewSharedBuffer()
+	var expectedResult, actualResult bytes.Buffer
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		block := make([]byte, 256)
+		for i := range block {
+			block[i] = byte(i)
+		}
+		for blockSize := 1; blockSize <= 256; blockSize++ {
+			for i := 0; i < 256; i++ {
+				expectedResult.Write(block[:blockSize])
+				n, err := b.Write(block[:blockSize])
+				if n != blockSize || err != nil {
+					t.Fatalf("write error: %d %s", n, err)
+				}
+			}
+		}
+		wg.Done()
+	}()
+	go func() {
+		block := make([]byte, 256)
+		// Change block sizes in opposition to the write thread, to test blocking for new data.
+		for blockSize := 256; blockSize > 0; blockSize-- {
+			for i := 0; i < 256; i++ {
+				n, err := io.ReadFull(b, block[:blockSize])
+				if n != blockSize || err != nil {
+					t.Fatalf("read error: %d %s", n, err)
+				}
+				actualResult.Write(block[:blockSize])
+			}
+		}
+		wg.Done()
+	}()
+	wg.Wait()
+	if bytes.Compare(expectedResult.Bytes(), actualResult.Bytes()) != 0 {
+		t.Fatal("Result diverged")
+	}
+}
+
+func TestSharedBufferClose(t *testing.T) {
+	b := NewSharedBuffer()
+	testData := []byte("Hello world")
+	AssertIOReturnIsGood(t, len(testData))(b.Write(testData))
+	err := b.Close()
+	if err != nil {
+		t.Fatalf("unexpected error from Close: %s", err)
+	}
+	bytesRead := make([]byte, len(testData))
+	AssertIOReturnIsGood(t, len(testData))(b.Read(bytesRead))
+	n, err := b.Read(bytesRead)
+	if n != 0 {
+		t.Fatalf("extra bytes received: %d", n)
+	}
+	if err != io.EOF {
+		t.Fatalf("expected EOF, got %s", err)
+	}
+}

h2mux/signal.go

@@ -0,0 +1,34 @@
+package h2mux
+
+// Signal describes an event that can be waited on for at least one signal.
+// Signalling the event while it is in the signalled state is a noop.
+// When the waiter wakes up, the signal is set to unsignalled.
+// It is a way for any number of writers to inform a reader (without blocking)
+// that an event has happened.
+type Signal struct {
+	c chan struct{}
+}
+
+// NewSignal creates a new Signal.
+func NewSignal() Signal {
+	return Signal{c: make(chan struct{}, 1)}
+}
+
+// Signal signals the event.
+func (s Signal) Signal() {
+	// This channel is buffered, so the nonblocking send will always succeed if the buffer is empty.
+	select {
+	case s.c <- struct{}{}:
+	default:
+	}
+}
+
+// Wait for the event to be signalled.
+func (s Signal) Wait() {
+	<-s.c
+}
+
+// WaitChannel returns a channel that is readable after Signal is called.
+func (s Signal) WaitChannel() <-chan struct{} {
+	return s.c
+}

h2mux/streamerrormap.go

@@ -0,0 +1,47 @@
+package h2mux
+
+import (
+	"sync"
+
+	"golang.org/x/net/http2"
+)
+
+// StreamErrorMap is used to track stream errors. This is a separate structure to ActiveStreamMap because
+// errors can be raised against non-existent or closed streams.
+type StreamErrorMap struct {
+	sync.RWMutex
+	// errors tracks per-stream errors
+	errors map[uint32]http2.ErrCode
+	// hasError is signaled whenever an error is raised.
+	hasError Signal
+}
+
+// NewStreamErrorMap creates a new StreamErrorMap.
+func NewStreamErrorMap() *StreamErrorMap {
+	return &StreamErrorMap{
+		errors:   make(map[uint32]http2.ErrCode),
+		hasError: NewSignal(),
+	}
+}
+
+// RaiseError raises a stream error.
+func (s *StreamErrorMap) RaiseError(streamID uint32, err http2.ErrCode) {
+	s.Lock()
+	s.errors[streamID] = err
+	s.Unlock()
+	s.hasError.Signal()
+}
+
+// GetSignalChan returns a channel that is signalled when an error is raised.
+func (s *StreamErrorMap) GetSignalChan() <-chan struct{} {
+	return s.hasError.WaitChannel()
+}
+
+// GetErrors retrieves all errors currently raised. This resets the currently-tracked errors.
+func (s *StreamErrorMap) GetErrors() map[uint32]http2.ErrCode {
+	s.Lock()
+	errors := s.errors
+	s.errors = make(map[uint32]http2.ErrCode)
+	s.Unlock()
+	return errors
+}