Update libkv dependency

vendor/google.golang.org/grpc/transport/http2_client.go

@@ -1,33 +1,18 @@
 /*
  *
- * Copyright 2014, Google Inc.
- * All rights reserved.
+ * Copyright 2014 gRPC authors.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
  *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  *
  */
 
@@ -35,7 +20,6 @@ package transport
 
 import (
 	"bytes"
-	"fmt"
 	"io"
 	"math"
 	"net"
@@ -49,11 +33,11 @@ import (
 	"golang.org/x/net/http2/hpack"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
-	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/peer"
 	"google.golang.org/grpc/stats"
+	"google.golang.org/grpc/status"
 )
 
 // http2Client implements the ClientTransport interface with HTTP2.
@@ -91,7 +75,7 @@ type http2Client struct {
 
 	// controlBuf delivers all the control related tasks (e.g., window
 	// updates, reset streams, and various settings) to the controller.
-	controlBuf *recvBuffer
+	controlBuf *controlBuffer
 	fc         *inFlow
 	// sendQuotaPool provides flow control to outbound message.
 	sendQuotaPool *quotaPool
@@ -101,6 +85,8 @@ type http2Client struct {
 	// The scheme used: https if TLS is on, http otherwise.
 	scheme string
 
+	isSecure bool
+
 	creds []credentials.PerRPCCredentials
 
 	// Boolean to keep track of reading activity on transport.
@@ -110,6 +96,10 @@ type http2Client struct {
 
 	statsHandler stats.Handler
 
+	initialWindowSize int32
+
+	bdpEst *bdpEstimator
+
 	mu            sync.Mutex     // guard the following variables
 	state         transportState // the state of underlying connection
 	activeStreams map[uint32]*Stream
@@ -121,6 +111,9 @@ type http2Client struct {
 	goAwayID uint32
 	// prevGoAway ID records the Last-Stream-ID in the previous GOAway frame.
 	prevGoAwayID uint32
+	// goAwayReason records the http2.ErrCode and debug data received with the
+	// GoAway frame.
+	goAwayReason GoAwayReason
 }
 
 func dial(ctx context.Context, fn func(context.Context, string) (net.Conn, error), addr string) (net.Conn, error) {
@@ -166,9 +159,9 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 	conn, err := dial(ctx, opts.Dialer, addr.Addr)
 	if err != nil {
 		if opts.FailOnNonTempDialError {
-			return nil, connectionErrorf(isTemporary(err), err, "transport: %v", err)
+			return nil, connectionErrorf(isTemporary(err), err, "transport: error while dialing: %v", err)
 		}
-		return nil, connectionErrorf(true, err, "transport: %v", err)
+		return nil, connectionErrorf(true, err, "transport: Error while dialing %v", err)
 	}
 	// Any further errors will close the underlying connection
 	defer func(conn net.Conn) {
@@ -176,7 +169,10 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 			conn.Close()
 		}
 	}(conn)
-	var authInfo credentials.AuthInfo
+	var (
+		isSecure bool
+		authInfo credentials.AuthInfo
+	)
 	if creds := opts.TransportCredentials; creds != nil {
 		scheme = "https"
 		conn, authInfo, err = creds.ClientHandshake(ctx, addr.Addr, conn)
@@ -184,53 +180,68 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 			// Credentials handshake errors are typically considered permanent
 			// to avoid retrying on e.g. bad certificates.
 			temp := isTemporary(err)
-			return nil, connectionErrorf(temp, err, "transport: %v", err)
+			return nil, connectionErrorf(temp, err, "transport: authentication handshake failed: %v", err)
 		}
-	}
-	ua := primaryUA
-	if opts.UserAgent != "" {
-		ua = opts.UserAgent + " " + ua
+		isSecure = true
 	}
 	kp := opts.KeepaliveParams
 	// Validate keepalive parameters.
 	if kp.Time == 0 {
-		kp.Time = defaultKeepaliveTime
+		kp.Time = defaultClientKeepaliveTime
 	}
 	if kp.Timeout == 0 {
-		kp.Timeout = defaultKeepaliveTimeout
+		kp.Timeout = defaultClientKeepaliveTimeout
+	}
+	dynamicWindow := true
+	icwz := int32(initialWindowSize)
+	if opts.InitialConnWindowSize >= defaultWindowSize {
+		icwz = opts.InitialConnWindowSize
+		dynamicWindow = false
 	}
 	var buf bytes.Buffer
 	t := &http2Client{
 		ctx:        ctx,
 		target:     addr.Addr,
-		userAgent:  ua,
+		userAgent:  opts.UserAgent,
 		md:         addr.Metadata,
 		conn:       conn,
 		remoteAddr: conn.RemoteAddr(),
 		localAddr:  conn.LocalAddr(),
 		authInfo:   authInfo,
 		// The client initiated stream id is odd starting from 1.
-		nextID:          1,
-		writableChan:    make(chan int, 1),
-		shutdownChan:    make(chan struct{}),
-		errorChan:       make(chan struct{}),
-		goAway:          make(chan struct{}),
-		awakenKeepalive: make(chan struct{}, 1),
-		framer:          newFramer(conn),
-		hBuf:            &buf,
-		hEnc:            hpack.NewEncoder(&buf),
-		controlBuf:      newRecvBuffer(),
-		fc:              &inFlow{limit: initialConnWindowSize},
-		sendQuotaPool:   newQuotaPool(defaultWindowSize),
-		scheme:          scheme,
-		state:           reachable,
-		activeStreams:   make(map[uint32]*Stream),
-		creds:           opts.PerRPCCredentials,
-		maxStreams:      defaultMaxStreamsClient,
-		streamsQuota:    newQuotaPool(defaultMaxStreamsClient),
-		streamSendQuota: defaultWindowSize,
-		kp:              kp,
-		statsHandler:    opts.StatsHandler,
+		nextID:            1,
+		writableChan:      make(chan int, 1),
+		shutdownChan:      make(chan struct{}),
+		errorChan:         make(chan struct{}),
+		goAway:            make(chan struct{}),
+		awakenKeepalive:   make(chan struct{}, 1),
+		framer:            newFramer(conn),
+		hBuf:              &buf,
+		hEnc:              hpack.NewEncoder(&buf),
+		controlBuf:        newControlBuffer(),
+		fc:                &inFlow{limit: uint32(icwz)},
+		sendQuotaPool:     newQuotaPool(defaultWindowSize),
+		scheme:            scheme,
+		state:             reachable,
+		activeStreams:     make(map[uint32]*Stream),
+		isSecure:          isSecure,
+		creds:             opts.PerRPCCredentials,
+		maxStreams:        defaultMaxStreamsClient,
+		streamsQuota:      newQuotaPool(defaultMaxStreamsClient),
+		streamSendQuota:   defaultWindowSize,
+		kp:                kp,
+		statsHandler:      opts.StatsHandler,
+		initialWindowSize: initialWindowSize,
+	}
+	if opts.InitialWindowSize >= defaultWindowSize {
+		t.initialWindowSize = opts.InitialWindowSize
+		dynamicWindow = false
+	}
+	if dynamicWindow {
+		t.bdpEst = &bdpEstimator{
+			bdp:               initialWindowSize,
+			updateFlowControl: t.updateFlowControl,
+		}
 	}
 	// Make sure awakenKeepalive can't be written upon.
 	// keepalive routine will make it writable, if need be.
@@ -253,29 +264,29 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 	n, err := t.conn.Write(clientPreface)
 	if err != nil {
 		t.Close()
-		return nil, connectionErrorf(true, err, "transport: %v", err)
+		return nil, connectionErrorf(true, err, "transport: failed to write client preface: %v", err)
 	}
 	if n != len(clientPreface) {
 		t.Close()
 		return nil, connectionErrorf(true, err, "transport: preface mismatch, wrote %d bytes; want %d", n, len(clientPreface))
 	}
-	if initialWindowSize != defaultWindowSize {
+	if t.initialWindowSize != defaultWindowSize {
 		err = t.framer.writeSettings(true, http2.Setting{
 			ID:  http2.SettingInitialWindowSize,
-			Val: uint32(initialWindowSize),
+			Val: uint32(t.initialWindowSize),
 		})
 	} else {
 		err = t.framer.writeSettings(true)
 	}
 	if err != nil {
 		t.Close()
-		return nil, connectionErrorf(true, err, "transport: %v", err)
+		return nil, connectionErrorf(true, err, "transport: failed to write initial settings frame: %v", err)
 	}
 	// Adjust the connection flow control window if needed.
-	if delta := uint32(initialConnWindowSize - defaultWindowSize); delta > 0 {
+	if delta := uint32(icwz - defaultWindowSize); delta > 0 {
 		if err := t.framer.writeWindowUpdate(true, 0, delta); err != nil {
 			t.Close()
-			return nil, connectionErrorf(true, err, "transport: %v", err)
+			return nil, connectionErrorf(true, err, "transport: failed to write window update: %v", err)
 		}
 	}
 	go t.controller()
@@ -295,27 +306,33 @@ func (t *http2Client) newStream(ctx context.Context, callHdr *CallHdr) *Stream {
 		method:        callHdr.Method,
 		sendCompress:  callHdr.SendCompress,
 		buf:           newRecvBuffer(),
-		fc:            &inFlow{limit: initialWindowSize},
+		fc:            &inFlow{limit: uint32(t.initialWindowSize)},
 		sendQuotaPool: newQuotaPool(int(t.streamSendQuota)),
 		headerChan:    make(chan struct{}),
 	}
 	t.nextID += 2
-	s.windowHandler = func(n int) {
-		t.updateWindow(s, uint32(n))
+	s.requestRead = func(n int) {
+		t.adjustWindow(s, uint32(n))
 	}
 	// The client side stream context should have exactly the same life cycle with the user provided context.
 	// That means, s.ctx should be read-only. And s.ctx is done iff ctx is done.
 	// So we use the original context here instead of creating a copy.
 	s.ctx = ctx
-	s.dec = &recvBufferReader{
-		ctx:    s.ctx,
-		goAway: s.goAway,
-		recv:   s.buf,
+	s.trReader = &transportReader{
+		reader: &recvBufferReader{
+			ctx:    s.ctx,
+			goAway: s.goAway,
+			recv:   s.buf,
+		},
+		windowHandler: func(n int) {
+			t.updateWindow(s, uint32(n))
+		},
 	}
+
 	return s
 }
 
-// NewStream creates a stream and register it into the transport as "active"
+// NewStream creates a stream and registers it into the transport as "active"
 // streams.
 func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Stream, err error) {
 	pr := &peer.Peer{
@@ -325,10 +342,13 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 	if t.authInfo != nil {
 		pr.AuthInfo = t.authInfo
 	}
-	userCtx := ctx
 	ctx = peer.NewContext(ctx, pr)
-	authData := make(map[string]string)
-	for _, c := range t.creds {
+	var (
+		authData = make(map[string]string)
+		audience string
+	)
+	// Create an audience string only if needed.
+	if len(t.creds) > 0 || callHdr.Creds != nil {
 		// Construct URI required to get auth request metadata.
 		var port string
 		if pos := strings.LastIndex(t.target, ":"); pos != -1 {
@@ -339,17 +359,39 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 		}
 		pos := strings.LastIndex(callHdr.Method, "/")
 		if pos == -1 {
-			return nil, streamErrorf(codes.InvalidArgument, "transport: malformed method name: %q", callHdr.Method)
+			pos = len(callHdr.Method)
 		}
-		audience := "https://" + callHdr.Host + port + callHdr.Method[:pos]
+		audience = "https://" + callHdr.Host + port + callHdr.Method[:pos]
+	}
+	for _, c := range t.creds {
 		data, err := c.GetRequestMetadata(ctx, audience)
 		if err != nil {
-			return nil, streamErrorf(codes.InvalidArgument, "transport: %v", err)
+			return nil, streamErrorf(codes.Internal, "transport: %v", err)
 		}
 		for k, v := range data {
+			// Capital header names are illegal in HTTP/2.
+			k = strings.ToLower(k)
 			authData[k] = v
 		}
 	}
+	callAuthData := make(map[string]string)
+	// Check if credentials.PerRPCCredentials were provided via call options.
+	// Note: if these credentials are provided both via dial options and call
+	// options, then both sets of credentials will be applied.
+	if callCreds := callHdr.Creds; callCreds != nil {
+		if !t.isSecure && callCreds.RequireTransportSecurity() {
+			return nil, streamErrorf(codes.Unauthenticated, "transport: cannot send secure credentials on an insecure conneciton")
+		}
+		data, err := callCreds.GetRequestMetadata(ctx, audience)
+		if err != nil {
+			return nil, streamErrorf(codes.Internal, "transport: %v", err)
+		}
+		for k, v := range data {
+			// Capital header names are illegal in HTTP/2
+			k = strings.ToLower(k)
+			callAuthData[k] = v
+		}
+	}
 	t.mu.Lock()
 	if t.activeStreams == nil {
 		t.mu.Unlock()
@@ -392,7 +434,6 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 		return nil, ErrConnClosing
 	}
 	s := t.newStream(ctx, callHdr)
-	s.clientStatsCtx = userCtx
 	t.activeStreams[s.id] = s
 	// If the number of active streams change from 0 to 1, then check if keepalive
 	// has gone dormant. If so, wake it up.
@@ -428,33 +469,32 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 	}
 
 	for k, v := range authData {
-		// Capital header names are illegal in HTTP/2.
-		k = strings.ToLower(k)
-		t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: v})
+		t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
+	}
+	for k, v := range callAuthData {
+		t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
 	}
 	var (
-		hasMD      bool
 		endHeaders bool
 	)
-	if md, ok := metadata.FromContext(ctx); ok {
-		hasMD = true
-		for k, v := range md {
+	if md, ok := metadata.FromOutgoingContext(ctx); ok {
+		for k, vv := range md {
 			// HTTP doesn't allow you to set pseudoheaders after non pseudoheaders were set.
 			if isReservedHeader(k) {
 				continue
 			}
-			for _, entry := range v {
-				t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
+			for _, v := range vv {
+				t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
 			}
 		}
 	}
 	if md, ok := t.md.(*metadata.MD); ok {
-		for k, v := range *md {
+		for k, vv := range *md {
 			if isReservedHeader(k) {
 				continue
 			}
-			for _, entry := range v {
-				t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
+			for _, v := range vv {
+				t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
 			}
 		}
 	}
@@ -469,7 +509,7 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 			endHeaders = true
 		}
 		var flush bool
-		if endHeaders && (hasMD || callHdr.Flush) {
+		if callHdr.Flush && endHeaders {
 			flush = true
 		}
 		if first {
@@ -494,6 +534,10 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 			return nil, connectionErrorf(true, err, "transport: %v", err)
 		}
 	}
+	s.mu.Lock()
+	s.bytesSent = true
+	s.mu.Unlock()
+
 	if t.statsHandler != nil {
 		outHeader := &stats.OutHeader{
 			Client:      true,
@@ -503,7 +547,7 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 			LocalAddr:   t.localAddr,
 			Compression: callHdr.SendCompress,
 		}
-		t.statsHandler.HandleRPC(s.clientStatsCtx, outHeader)
+		t.statsHandler.HandleRPC(s.ctx, outHeader)
 	}
 	t.writableChan <- 0
 	return s, nil
@@ -517,6 +561,10 @@ func (t *http2Client) CloseStream(s *Stream, err error) {
 		t.mu.Unlock()
 		return
 	}
+	if err != nil {
+		// notify in-flight streams, before the deletion
+		s.write(recvMsg{err: err})
+	}
 	delete(t.activeStreams, s.id)
 	if t.state == draining && len(t.activeStreams) == 0 {
 		// The transport is draining and s is the last live stream on t.
@@ -546,11 +594,6 @@ func (t *http2Client) CloseStream(s *Stream, err error) {
 	s.mu.Lock()
 	rstStream = s.rstStream
 	rstError = s.rstError
-	if q := s.fc.resetPendingData(); q > 0 {
-		if n := t.fc.onRead(q); n > 0 {
-			t.controlBuf.put(&windowUpdate{0, n})
-		}
-	}
 	if s.state == streamDone {
 		s.mu.Unlock()
 		return
@@ -759,6 +802,24 @@ func (t *http2Client) getStream(f http2.Frame) (*Stream, bool) {
 	return s, ok
 }
 
+// adjustWindow sends out extra window update over the initial window size
+// of stream if the application is requesting data larger in size than
+// the window.
+func (t *http2Client) adjustWindow(s *Stream, n uint32) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.state == streamDone {
+		return
+	}
+	if w := s.fc.maybeAdjust(n); w > 0 {
+		// Piggyback conneciton's window update along.
+		if cw := t.fc.resetPendingUpdate(); cw > 0 {
+			t.controlBuf.put(&windowUpdate{0, cw, false})
+		}
+		t.controlBuf.put(&windowUpdate{s.id, w, true})
+	}
+}
+
 // updateWindow adjusts the inbound quota for the stream and the transport.
 // Window updates will deliver to the controller for sending when
 // the cumulative quota exceeds the corresponding threshold.
@@ -768,57 +829,87 @@ func (t *http2Client) updateWindow(s *Stream, n uint32) {
 	if s.state == streamDone {
 		return
 	}
-	if w := t.fc.onRead(n); w > 0 {
-		t.controlBuf.put(&windowUpdate{0, w})
-	}
 	if w := s.fc.onRead(n); w > 0 {
-		t.controlBuf.put(&windowUpdate{s.id, w})
+		if cw := t.fc.resetPendingUpdate(); cw > 0 {
+			t.controlBuf.put(&windowUpdate{0, cw, false})
+		}
+		t.controlBuf.put(&windowUpdate{s.id, w, true})
 	}
 }
 
+// updateFlowControl updates the incoming flow control windows
+// for the transport and the stream based on the current bdp
+// estimation.
+func (t *http2Client) updateFlowControl(n uint32) {
+	t.mu.Lock()
+	for _, s := range t.activeStreams {
+		s.fc.newLimit(n)
+	}
+	t.initialWindowSize = int32(n)
+	t.mu.Unlock()
+	t.controlBuf.put(&windowUpdate{0, t.fc.newLimit(n), false})
+	t.controlBuf.put(&settings{
+		ack: false,
+		ss: []http2.Setting{
+			{
+				ID:  http2.SettingInitialWindowSize,
+				Val: uint32(n),
+			},
+		},
+	})
+}
+
 func (t *http2Client) handleData(f *http2.DataFrame) {
 	size := f.Header().Length
-	if err := t.fc.onData(uint32(size)); err != nil {
-		t.notifyError(connectionErrorf(true, err, "%v", err))
-		return
+	var sendBDPPing bool
+	if t.bdpEst != nil {
+		sendBDPPing = t.bdpEst.add(uint32(size))
+	}
+	// Decouple connection's flow control from application's read.
+	// An update on connection's flow control should not depend on
+	// whether user application has read the data or not. Such a
+	// restriction is already imposed on the stream's flow control,
+	// and therefore the sender will be blocked anyways.
+	// Decoupling the connection flow control will prevent other
+	// active(fast) streams from starving in presence of slow or
+	// inactive streams.
+	//
+	// Furthermore, if a bdpPing is being sent out we can piggyback
+	// connection's window update for the bytes we just received.
+	if sendBDPPing {
+		t.controlBuf.put(&windowUpdate{0, uint32(size), false})
+		t.controlBuf.put(bdpPing)
+	} else {
+		if err := t.fc.onData(uint32(size)); err != nil {
+			t.notifyError(connectionErrorf(true, err, "%v", err))
+			return
+		}
+		if w := t.fc.onRead(uint32(size)); w > 0 {
+			t.controlBuf.put(&windowUpdate{0, w, true})
+		}
 	}
 	// Select the right stream to dispatch.
 	s, ok := t.getStream(f)
 	if !ok {
-		if w := t.fc.onRead(uint32(size)); w > 0 {
-			t.controlBuf.put(&windowUpdate{0, w})
-		}
 		return
 	}
 	if size > 0 {
-		if f.Header().Flags.Has(http2.FlagDataPadded) {
-			if w := t.fc.onRead(uint32(size) - uint32(len(f.Data()))); w > 0 {
-				t.controlBuf.put(&windowUpdate{0, w})
-			}
-		}
 		s.mu.Lock()
 		if s.state == streamDone {
 			s.mu.Unlock()
-			// The stream has been closed. Release the corresponding quota.
-			if w := t.fc.onRead(uint32(size)); w > 0 {
-				t.controlBuf.put(&windowUpdate{0, w})
-			}
 			return
 		}
 		if err := s.fc.onData(uint32(size)); err != nil {
-			s.state = streamDone
-			s.statusCode = codes.Internal
-			s.statusDesc = err.Error()
 			s.rstStream = true
 			s.rstError = http2.ErrCodeFlowControl
-			close(s.done)
+			s.finish(status.New(codes.Internal, err.Error()))
 			s.mu.Unlock()
 			s.write(recvMsg{err: io.EOF})
 			return
 		}
 		if f.Header().Flags.Has(http2.FlagDataPadded) {
 			if w := s.fc.onRead(uint32(size) - uint32(len(f.Data()))); w > 0 {
-				t.controlBuf.put(&windowUpdate{s.id, w})
+				t.controlBuf.put(&windowUpdate{s.id, w, true})
 			}
 		}
 		s.mu.Unlock()
@@ -839,10 +930,7 @@ func (t *http2Client) handleData(f *http2.DataFrame) {
 			s.mu.Unlock()
 			return
 		}
-		s.state = streamDone
-		s.statusCode = codes.Internal
-		s.statusDesc = "server closed the stream without sending trailers"
-		close(s.done)
+		s.finish(status.New(codes.Internal, "server closed the stream without sending trailers"))
 		s.mu.Unlock()
 		s.write(recvMsg{err: io.EOF})
 	}
@@ -858,18 +946,16 @@ func (t *http2Client) handleRSTStream(f *http2.RSTStreamFrame) {
 		s.mu.Unlock()
 		return
 	}
-	s.state = streamDone
 	if !s.headerDone {
 		close(s.headerChan)
 		s.headerDone = true
 	}
-	s.statusCode, ok = http2ErrConvTab[http2.ErrCode(f.ErrCode)]
+	statusCode, ok := http2ErrConvTab[http2.ErrCode(f.ErrCode)]
 	if !ok {
-		grpclog.Println("transport: http2Client.handleRSTStream found no mapped gRPC status for the received http2 error ", f.ErrCode)
-		s.statusCode = codes.Unknown
+		warningf("transport: http2Client.handleRSTStream found no mapped gRPC status for the received http2 error %v", f.ErrCode)
+		statusCode = codes.Unknown
 	}
-	s.statusDesc = fmt.Sprintf("stream terminated by RST_STREAM with error code: %d", f.ErrCode)
-	close(s.done)
+	s.finish(status.Newf(statusCode, "stream terminated by RST_STREAM with error code: %d", f.ErrCode))
 	s.mu.Unlock()
 	s.write(recvMsg{err: io.EOF})
 }
@@ -888,7 +974,11 @@ func (t *http2Client) handleSettings(f *http2.SettingsFrame) {
 }
 
 func (t *http2Client) handlePing(f *http2.PingFrame) {
-	if f.IsAck() { // Do nothing.
+	if f.IsAck() {
+		// Maybe it's a BDP ping.
+		if t.bdpEst != nil {
+			t.bdpEst.calculate(f.Data)
+		}
 		return
 	}
 	pingAck := &ping{ack: true}
@@ -897,6 +987,9 @@ func (t *http2Client) handlePing(f *http2.PingFrame) {
 }
 
 func (t *http2Client) handleGoAway(f *http2.GoAwayFrame) {
+	if f.ErrCode == http2.ErrCodeEnhanceYourCalm {
+		infof("Client received GoAway with http2.ErrCodeEnhanceYourCalm.")
+	}
 	t.mu.Lock()
 	if t.state == reachable || t.state == draining {
 		if f.LastStreamID > 0 && f.LastStreamID%2 != 1 {
@@ -918,6 +1011,7 @@ func (t *http2Client) handleGoAway(f *http2.GoAwayFrame) {
 			t.mu.Unlock()
 			return
 		default:
+			t.setGoAwayReason(f)
 		}
 		t.goAwayID = f.LastStreamID
 		close(t.goAway)
@@ -925,6 +1019,26 @@ func (t *http2Client) handleGoAway(f *http2.GoAwayFrame) {
 	t.mu.Unlock()
 }
 
+// setGoAwayReason sets the value of t.goAwayReason based
+// on the GoAway frame received.
+// It expects a lock on transport's mutext to be held by
+// the caller.
+func (t *http2Client) setGoAwayReason(f *http2.GoAwayFrame) {
+	t.goAwayReason = NoReason
+	switch f.ErrCode {
+	case http2.ErrCodeEnhanceYourCalm:
+		if string(f.DebugData()) == "too_many_pings" {
+			t.goAwayReason = TooManyPings
+		}
+	}
+}
+
+func (t *http2Client) GetGoAwayReason() GoAwayReason {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	return t.goAwayReason
+}
+
 func (t *http2Client) handleWindowUpdate(f *http2.WindowUpdateFrame) {
 	id := f.Header().StreamID
 	incr := f.Increment
@@ -943,18 +1057,18 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 	if !ok {
 		return
 	}
+	s.mu.Lock()
+	s.bytesReceived = true
+	s.mu.Unlock()
 	var state decodeState
-	for _, hf := range frame.Fields {
-		state.processHeaderField(hf)
-	}
-	if state.err != nil {
+	if err := state.decodeResponseHeader(frame); err != nil {
 		s.mu.Lock()
 		if !s.headerDone {
 			close(s.headerChan)
 			s.headerDone = true
 		}
 		s.mu.Unlock()
-		s.write(recvMsg{err: state.err})
+		s.write(recvMsg{err: err})
 		// Something wrong. Stops reading even when there is remaining.
 		return
 	}
@@ -968,13 +1082,13 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 					Client:     true,
 					WireLength: int(frame.Header().Length),
 				}
-				t.statsHandler.HandleRPC(s.clientStatsCtx, inHeader)
+				t.statsHandler.HandleRPC(s.ctx, inHeader)
 			} else {
 				inTrailer := &stats.InTrailer{
 					Client:     true,
 					WireLength: int(frame.Header().Length),
 				}
-				t.statsHandler.HandleRPC(s.clientStatsCtx, inTrailer)
+				t.statsHandler.HandleRPC(s.ctx, inTrailer)
 			}
 		}
 	}()
@@ -999,10 +1113,7 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 	if len(state.mdata) > 0 {
 		s.trailer = state.mdata
 	}
-	s.statusCode = state.statusCode
-	s.statusDesc = state.statusDesc
-	close(s.done)
-	s.state = streamDone
+	s.finish(state.status())
 	s.mu.Unlock()
 	s.write(recvMsg{err: io.EOF})
 }
@@ -1077,7 +1188,7 @@ func (t *http2Client) reader() {
 		case *http2.WindowUpdateFrame:
 			t.handleWindowUpdate(frame)
 		default:
-			grpclog.Printf("transport: http2Client.reader got unhandled frame type %v.", frame)
+			errorf("transport: http2Client.reader got unhandled frame type %v.", frame)
 		}
 	}
 }
@@ -1101,7 +1212,7 @@ func (t *http2Client) applySettings(ss []http2.Setting) {
 			t.mu.Lock()
 			for _, stream := range t.activeStreams {
 				// Adjust the sending quota for each stream.
-				stream.sendQuotaPool.add(int(s.Val - t.streamSendQuota))
+				stream.sendQuotaPool.add(int(s.Val) - int(t.streamSendQuota))
 			}
 			t.streamSendQuota = s.Val
 			t.mu.Unlock()
@@ -1120,7 +1231,7 @@ func (t *http2Client) controller() {
 			case <-t.writableChan:
 				switch i := i.(type) {
 				case *windowUpdate:
-					t.framer.writeWindowUpdate(true, i.streamID, i.increment)
+					t.framer.writeWindowUpdate(i.flush, i.streamID, i.increment)
 				case *settings:
 					if i.ack {
 						t.framer.writeSettingsAck(true)
@@ -1139,9 +1250,12 @@ func (t *http2Client) controller() {
 				case *flushIO:
 					t.framer.flushWrite()
 				case *ping:
+					if !i.ack {
+						t.bdpEst.timesnap(i.data)
+					}
 					t.framer.writePing(true, i.ack, i.data)
 				default:
-					grpclog.Printf("transport: http2Client.controller got unexpected item type %v\n", i)
+					errorf("transport: http2Client.controller got unexpected item type %v\n", i)
 				}
 				t.writableChan <- 0
 				continue
@@ -1228,7 +1342,7 @@ func (t *http2Client) notifyError(err error) {
 	if t.state == reachable {
 		t.state = unreachable
 		close(t.errorChan)
-		grpclog.Printf("transport: http2Client.notifyError got notified that the client transport was broken %v.", err)
+		infof("transport: http2Client.notifyError got notified that the client transport was broken %v.", err)
 	}
 	t.mu.Unlock()
 }