/*
*
* Copyright 2014, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * 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.
*
* 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.
*
*/
package transport
import (
"bytes"
"errors"
"io"
"math"
"math/rand"
"net"
"strconv"
"sync"
"sync/atomic"
"time"
"github.com/golang/protobuf/proto"
"golang.org/x/net/context"
"golang.org/x/net/http2"
"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"
"google.golang.org/grpc/tap"
)
// ErrIllegalHeaderWrite indicates that setting header is illegal because of
// the stream's state.
var ErrIllegalHeaderWrite = errors.New("transport: the stream is done or WriteHeader was already called")
// http2Server implements the ServerTransport interface with HTTP2.
type http2Server struct {
ctx context.Context
conn net.Conn
remoteAddr net.Addr
localAddr net.Addr
maxStreamID uint32 // max stream ID ever seen
authInfo credentials.AuthInfo // auth info about the connection
inTapHandle tap.ServerInHandle
// writableChan synchronizes write access to the transport.
// A writer acquires the write lock by receiving a value on writableChan
// and releases it by sending on writableChan.
writableChan chan int
// shutdownChan is closed when Close is called.
// Blocking operations should select on shutdownChan to avoid
// blocking forever after Close.
shutdownChan chan struct{}
framer *framer
hBuf *bytes.Buffer // the buffer for HPACK encoding
hEnc *hpack.Encoder // HPACK encoder
// The max number of concurrent streams.
maxStreams uint32
// controlBuf delivers all the control related tasks (e.g., window
// updates, reset streams, and various settings) to the controller.
controlBuf *recvBuffer
fc *inFlow
// sendQuotaPool provides flow control to outbound message.
sendQuotaPool *quotaPool
stats stats.Handler
// Flag to keep track of reading activity on transport.
// 1 is true and 0 is false.
activity uint32 // Accessed atomically.
// Keepalive and max-age parameters for the server.
kp keepalive.ServerParameters
// Keepalive enforcement policy.
kep keepalive.EnforcementPolicy
// The time instance last ping was received.
lastPingAt time.Time
// Number of times the client has violated keepalive ping policy so far.
pingStrikes uint8
// Flag to signify that number of ping strikes should be reset to 0.
// This is set whenever data or header frames are sent.
// 1 means yes.
resetPingStrikes uint32 // Accessed atomically.
mu sync.Mutex // guard the following
state transportState
activeStreams map[uint32]*Stream
// the per-stream outbound flow control window size set by the peer.
streamSendQuota uint32
// idle is the time instant when the connection went idle.
// This is either the begining of the connection or when the number of
// RPCs go down to 0.
// When the connection is busy, this value is set to 0.
idle time.Time
}
// newHTTP2Server constructs a ServerTransport based on HTTP2. ConnectionError is
// returned if something goes wrong.
func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err error) {
framer := newFramer(conn)
// Send initial settings as connection preface to client.
var settings []http2.Setting
// TODO(zhaoq): Have a better way to signal "no limit" because 0 is
// permitted in the HTTP2 spec.
maxStreams := config.MaxStreams
if maxStreams == 0 {
maxStreams = math.MaxUint32
} else {
settings = append(settings, http2.Setting{
ID: http2.SettingMaxConcurrentStreams,
Val: maxStreams,
})
}
if initialWindowSize != defaultWindowSize {
settings = append(settings, http2.Setting{
ID: http2.SettingInitialWindowSize,
Val: uint32(initialWindowSize)})
}
if err := framer.writeSettings(true, settings...); err != nil {
return nil, connectionErrorf(true, err, "transport: %v", err)
}
// Adjust the connection flow control window if needed.
if delta := uint32(initialConnWindowSize - defaultWindowSize); delta > 0 {
if err := framer.writeWindowUpdate(true, 0, delta); err != nil {
return nil, connectionErrorf(true, err, "transport: %v", err)
}
}
kp := config.KeepaliveParams
if kp.MaxConnectionIdle == 0 {
kp.MaxConnectionIdle = defaultMaxConnectionIdle
}
if kp.MaxConnectionAge == 0 {
kp.MaxConnectionAge = defaultMaxConnectionAge
}
// Add a jitter to MaxConnectionAge.
kp.MaxConnectionAge += getJitter(kp.MaxConnectionAge)
if kp.MaxConnectionAgeGrace == 0 {
kp.MaxConnectionAgeGrace = defaultMaxConnectionAgeGrace
}
if kp.Time == 0 {
kp.Time = defaultServerKeepaliveTime
}
if kp.Timeout == 0 {
kp.Timeout = defaultServerKeepaliveTimeout
}
kep := config.KeepalivePolicy
if kep.MinTime == 0 {
kep.MinTime = defaultKeepalivePolicyMinTime
}
var buf bytes.Buffer
t := &http2Server{
ctx: context.Background(),
conn: conn,
remoteAddr: conn.RemoteAddr(),
localAddr: conn.LocalAddr(),
authInfo: config.AuthInfo,
framer: framer,
hBuf: &buf,
hEnc: hpack.NewEncoder(&buf),
maxStreams: maxStreams,
inTapHandle: config.InTapHandle,
controlBuf: newRecvBuffer(),
fc: &inFlow{limit: initialConnWindowSize},
sendQuotaPool: newQuotaPool(defaultWindowSize),
state: reachable,
writableChan: make(chan int, 1),
shutdownChan: make(chan struct{}),
activeStreams: make(map[uint32]*Stream),
streamSendQuota: defaultWindowSize,
stats: config.StatsHandler,
kp: kp,
idle: time.Now(),
kep: kep,
}
if t.stats != nil {
t.ctx = t.stats.TagConn(t.ctx, &stats.ConnTagInfo{
RemoteAddr: t.remoteAddr,
LocalAddr: t.localAddr,
})
connBegin := &stats.ConnBegin{}
t.stats.HandleConn(t.ctx, connBegin)
}
go t.controller()
go t.keepalive()
t.writableChan <- 0
return t, nil
}
// operateHeader takes action on the decoded headers.
func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(*Stream), traceCtx func(context.Context, string) context.Context) (close bool) {
buf := newRecvBuffer()
s := &Stream{
id: frame.Header().StreamID,
st: t,
buf: buf,
fc: &inFlow{limit: initialWindowSize},
}
var state decodeState
for _, hf := range frame.Fields {
if err := state.processHeaderField(hf); err != nil {
if se, ok := err.(StreamError); ok {
t.controlBuf.put(&resetStream{s.id, statusCodeConvTab[se.Code]})
}
return
}
}
if frame.StreamEnded() {
// s is just created by the caller. No lock needed.
s.state = streamReadDone
}
s.recvCompress = state.encoding
if state.timeoutSet {
s.ctx, s.cancel = context.WithTimeout(t.ctx, state.timeout)
} else {
s.ctx, s.cancel = context.WithCancel(t.ctx)
}
pr := &peer.Peer{
Addr: t.remoteAddr,
}
// Attach Auth info if there is any.
if t.authInfo != nil {
pr.AuthInfo = t.authInfo
}
s.ctx = peer.NewContext(s.ctx, pr)
// Cache the current stream to the context so that the server application
// can find out. Required when the server wants to send some metadata
// back to the client (unary call only).
s.ctx = newContextWithStream(s.ctx, s)
// Attach the received metadata to the context.
if len(state.mdata) > 0 {
s.ctx = metadata.NewIncomingContext(s.ctx, state.mdata)
}
s.dec = &recvBufferReader{
ctx: s.ctx,
recv: s.buf,
}
s.recvCompress = state.encoding
s.method = state.method
if t.inTapHandle != nil {
var err error
info := &tap.Info{
FullMethodName: state.method,
}
s.ctx, err = t.inTapHandle(s.ctx, info)
if err != nil {
// TODO: Log the real error.
t.controlBuf.put(&resetStream{s.id, http2.ErrCodeRefusedStream})
return
}
}
t.mu.Lock()
if t.state != reachable {
t.mu.Unlock()
return
}
if uint32(len(t.activeStreams)) >= t.maxStreams {
t.mu.Unlock()
t.controlBuf.put(&resetStream{s.id, http2.ErrCodeRefusedStream})
return
}
if s.id%2 != 1 || s.id <= t.maxStreamID {
t.mu.Unlock()
// illegal gRPC stream id.
grpclog.Println("transport: http2Server.HandleStreams received an illegal stream id: ", s.id)
return true
}
t.maxStreamID = s.id
s.sendQuotaPool = newQuotaPool(int(t.streamSendQuota))
t.activeStreams[s.id] = s
if len(t.activeStreams) == 1 {
t.idle = time.Time{}
}
t.mu.Unlock()
s.windowHandler = func(n int) {
t.updateWindow(s, uint32(n))
}
s.ctx = traceCtx(s.ctx, s.method)
if t.stats != nil {
s.ctx = t.stats.TagRPC(s.ctx, &stats.RPCTagInfo{FullMethodName: s.method})
inHeader := &stats.InHeader{
FullMethod: s.method,
RemoteAddr: t.remoteAddr,
LocalAddr: t.localAddr,
Compression: s.recvCompress,
WireLength: int(frame.Header().Length),
}
t.stats.HandleRPC(s.ctx, inHeader)
}
handle(s)
return
}
// HandleStreams receives incoming streams using the given handler. This is
// typically run in a separate goroutine.
// traceCtx attaches trace to ctx and returns the new context.
func (t *http2Server) HandleStreams(handle func(*Stream), traceCtx func(context.Context, string) context.Context) {
// Check the validity of client preface.
preface := make([]byte, len(clientPreface))
if _, err := io.ReadFull(t.conn, preface); err != nil {
grpclog.Printf("transport: http2Server.HandleStreams failed to receive the preface from client: %v", err)
t.Close()
return
}
if !bytes.Equal(preface, clientPreface) {
grpclog.Printf("transport: http2Server.HandleStreams received bogus greeting from client: %q", preface)
t.Close()
return
}
frame, err := t.framer.readFrame()
if err == io.EOF || err == io.ErrUnexpectedEOF {
t.Close()
return
}
if err != nil {
grpclog.Printf("transport: http2Server.HandleStreams failed to read frame: %v", err)
t.Close()
return
}
atomic.StoreUint32(&t.activity, 1)
sf, ok := frame.(*http2.SettingsFrame)
if !ok {
grpclog.Printf("transport: http2Server.HandleStreams saw invalid preface type %T from client", frame)
t.Close()
return
}
t.handleSettings(sf)
for {
frame, err := t.framer.readFrame()
atomic.StoreUint32(&t.activity, 1)
if err != nil {
if se, ok := err.(http2.StreamError); ok {
t.mu.Lock()
s := t.activeStreams[se.StreamID]
t.mu.Unlock()
if s != nil {
t.closeStream(s)
}
t.controlBuf.put(&resetStream{se.StreamID, se.Code})
continue
}
if err == io.EOF || err == io.ErrUnexpectedEOF {
t.Close()
return
}
grpclog.Printf("transport: http2Server.HandleStreams failed to read frame: %v", err)
t.Close()
return
}
switch frame := frame.(type) {
case *http2.MetaHeadersFrame:
if t.operateHeaders(frame, handle, traceCtx) {
t.Close()
break
}
case *http2.DataFrame:
t.handleData(frame)
case *http2.RSTStreamFrame:
t.handleRSTStream(frame)
case *http2.SettingsFrame:
t.handleSettings(frame)
case *http2.PingFrame:
t.handlePing(frame)
case *http2.WindowUpdateFrame:
t.handleWindowUpdate(frame)
case *http2.GoAwayFrame:
// TODO: Handle GoAway from the client appropriately.
default:
grpclog.Printf("transport: http2Server.HandleStreams found unhandled frame type %v.", frame)
}
}
}
func (t *http2Server) getStream(f http2.Frame) (*Stream, bool) {
t.mu.Lock()
defer t.mu.Unlock()
if t.activeStreams == nil {
// The transport is closing.
return nil, false
}
s, ok := t.activeStreams[f.Header().StreamID]
if !ok {
// The stream is already done.
return nil, false
}
return s, 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.
func (t *http2Server) updateWindow(s *Stream, n uint32) {
s.mu.Lock()
defer s.mu.Unlock()
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})
}
}
func (t *http2Server) handleData(f *http2.DataFrame) {
size := f.Header().Length
if err := t.fc.onData(uint32(size)); err != nil {
grpclog.Printf("transport: http2Server %v", err)
t.Close()
return
}
// 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.mu.Unlock()
t.closeStream(s)
t.controlBuf.put(&resetStream{s.id, http2.ErrCodeFlowControl})
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})
}
}
s.mu.Unlock()
// TODO(bradfitz, zhaoq): A copy is required here because there is no
// guarantee f.Data() is consumed before the arrival of next frame.
// Can this copy be eliminated?
if len(f.Data()) > 0 {
data := make([]byte, len(f.Data()))
copy(data, f.Data())
s.write(recvMsg{data: data})
}
}
if f.Header().Flags.Has(http2.FlagDataEndStream) {
// Received the end of stream from the client.
s.mu.Lock()
if s.state != streamDone {
s.state = streamReadDone
}
s.mu.Unlock()
s.write(recvMsg{err: io.EOF})
}
}
func (t *http2Server) handleRSTStream(f *http2.RSTStreamFrame) {
s, ok := t.getStream(f)
if !ok {
return
}
t.closeStream(s)
}
func (t *http2Server) handleSettings(f *http2.SettingsFrame) {
if f.IsAck() {
return
}
var ss []http2.Setting
f.ForeachSetting(func(s http2.Setting) error {
ss = append(ss, s)
return nil
})
// The settings will be applied once the ack is sent.
t.controlBuf.put(&settings{ack: true, ss: ss})
}
const (
maxPingStrikes = 2
defaultPingTimeout = 2 * time.Hour
)
func (t *http2Server) handlePing(f *http2.PingFrame) {
if f.IsAck() { // Do nothing.
return
}
pingAck := &ping{ack: true}
copy(pingAck.data[:], f.Data[:])
t.controlBuf.put(pingAck)
now := time.Now()
defer func() {
t.lastPingAt = now
}()
// A reset ping strikes means that we don't need to check for policy
// violation for this ping and the pingStrikes counter should be set
// to 0.
if atomic.CompareAndSwapUint32(&t.resetPingStrikes, 1, 0) {
t.pingStrikes = 0
return
}
t.mu.Lock()
ns := len(t.activeStreams)
t.mu.Unlock()
if ns < 1 && !t.kep.PermitWithoutStream {
// Keepalive shouldn't be active thus, this new ping should
// have come after atleast defaultPingTimeout.
if t.lastPingAt.Add(defaultPingTimeout).After(now) {
t.pingStrikes++
}
} else {
// Check if keepalive policy is respected.
if t.lastPingAt.Add(t.kep.MinTime).After(now) {
t.pingStrikes++
}
}
if t.pingStrikes > maxPingStrikes {
// Send goaway and close the connection.
t.controlBuf.put(&goAway{code: http2.ErrCodeEnhanceYourCalm, debugData: []byte("too_many_pings")})
}
}
func (t *http2Server) handleWindowUpdate(f *http2.WindowUpdateFrame) {
id := f.Header().StreamID
incr := f.Increment
if id == 0 {
t.sendQuotaPool.add(int(incr))
return
}
if s, ok := t.getStream(f); ok {
s.sendQuotaPool.add(int(incr))
}
}
func (t *http2Server) writeHeaders(s *Stream, b *bytes.Buffer, endStream bool) error {
first := true
endHeaders := false
var err error
defer func() {
if err == nil {
// Reset ping strikes when seding headers since that might cause the
// peer to send ping.
atomic.StoreUint32(&t.resetPingStrikes, 1)
}
}()
// Sends the headers in a single batch.
for !endHeaders {
size := t.hBuf.Len()
if size > http2MaxFrameLen {
size = http2MaxFrameLen
} else {
endHeaders = true
}
if first {
p := http2.HeadersFrameParam{
StreamID: s.id,
BlockFragment: b.Next(size),
EndStream: endStream,
EndHeaders: endHeaders,
}
err = t.framer.writeHeaders(endHeaders, p)
first = false
} else {
err = t.framer.writeContinuation(endHeaders, s.id, endHeaders, b.Next(size))
}
if err != nil {
t.Close()
return connectionErrorf(true, err, "transport: %v", err)
}
}
return nil
}
// WriteHeader sends the header metedata md back to the client.
func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
s.mu.Lock()
if s.headerOk || s.state == streamDone {
s.mu.Unlock()
return ErrIllegalHeaderWrite
}
s.headerOk = true
if md.Len() > 0 {
if s.header.Len() > 0 {
s.header = metadata.Join(s.header, md)
} else {
s.header = md
}
}
md = s.header
s.mu.Unlock()
if _, err := wait(s.ctx, nil, nil, t.shutdownChan, t.writableChan); err != nil {
return err
}
t.hBuf.Reset()
t.hEnc.WriteField(hpack.HeaderField{Name: ":status", Value: "200"})
t.hEnc.WriteField(hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
if s.sendCompress != "" {
t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-encoding", Value: s.sendCompress})
}
for k, v := range md {
if isReservedHeader(k) {
// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
continue
}
for _, entry := range v {
t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
}
}
bufLen := t.hBuf.Len()
if err := t.writeHeaders(s, t.hBuf, false); err != nil {
return err
}
if t.stats != nil {
outHeader := &stats.OutHeader{
WireLength: bufLen,
}
t.stats.HandleRPC(s.Context(), outHeader)
}
t.writableChan <- 0
return nil
}
// WriteStatus sends stream status to the client and terminates the stream.
// There is no further I/O operations being able to perform on this stream.
// TODO(zhaoq): Now it indicates the end of entire stream. Revisit if early
// OK is adopted.
func (t *http2Server) WriteStatus(s *Stream, st *status.Status) error {
var headersSent, hasHeader bool
s.mu.Lock()
if s.state == streamDone {
s.mu.Unlock()
return nil
}
if s.headerOk {
headersSent = true
}
if s.header.Len() > 0 {
hasHeader = true
}
s.mu.Unlock()
if !headersSent && hasHeader {
t.WriteHeader(s, nil)
headersSent = true
}
if _, err := wait(s.ctx, nil, nil, t.shutdownChan, t.writableChan); err != nil {
return err
}
t.hBuf.Reset()
if !headersSent {
t.hEnc.WriteField(hpack.HeaderField{Name: ":status", Value: "200"})
t.hEnc.WriteField(hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
}
t.hEnc.WriteField(
hpack.HeaderField{
Name: "grpc-status",
Value: strconv.Itoa(int(st.Code())),
})
t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-message", Value: encodeGrpcMessage(st.Message())})
if p := st.Proto(); p != nil && len(p.Details) > 0 {
stBytes, err := proto.Marshal(p)
if err != nil {
// TODO: return error instead, when callers are able to handle it.
panic(err)
}
for k, v := range metadata.New(map[string]string{"grpc-status-details-bin": (string)(stBytes)}) {
for _, entry := range v {
t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
}
}
}
// Attach the trailer metadata.
for k, v := range s.trailer {
// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
if isReservedHeader(k) {
continue
}
for _, entry := range v {
t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
}
}
bufLen := t.hBuf.Len()
if err := t.writeHeaders(s, t.hBuf, true); err != nil {
t.Close()
return err
}
if t.stats != nil {
outTrailer := &stats.OutTrailer{
WireLength: bufLen,
}
t.stats.HandleRPC(s.Context(), outTrailer)
}
t.closeStream(s)
t.writableChan <- 0
return nil
}
// Write converts the data into HTTP2 data frame and sends it out. Non-nil error
// is returns if it fails (e.g., framing error, transport error).
func (t *http2Server) Write(s *Stream, data []byte, opts *Options) (err error) {
// TODO(zhaoq): Support multi-writers for a single stream.
var writeHeaderFrame bool
s.mu.Lock()
if s.state == streamDone {
s.mu.Unlock()
return streamErrorf(codes.Unknown, "the stream has been done")
}
if !s.headerOk {
writeHeaderFrame = true
}
s.mu.Unlock()
if writeHeaderFrame {
t.WriteHeader(s, nil)
}
defer func() {
if err == nil {
// Reset ping strikes when sending data since this might cause
// the peer to send ping.
atomic.StoreUint32(&t.resetPingStrikes, 1)
}
}()
r := bytes.NewBuffer(data)
for {
if r.Len() == 0 {
return nil
}
size := http2MaxFrameLen
// Wait until the stream has some quota to send the data.
sq, err := wait(s.ctx, nil, nil, t.shutdownChan, s.sendQuotaPool.acquire())
if err != nil {
return err
}
// Wait until the transport has some quota to send the data.
tq, err := wait(s.ctx, nil, nil, t.shutdownChan, t.sendQuotaPool.acquire())
if err != nil {
return err
}
if sq < size {
size = sq
}
if tq < size {
size = tq
}
p := r.Next(size)
ps := len(p)
if ps < sq {
// Overbooked stream quota. Return it back.
s.sendQuotaPool.add(sq - ps)
}
if ps < tq {
// Overbooked transport quota. Return it back.
t.sendQuotaPool.add(tq - ps)
}
t.framer.adjustNumWriters(1)
// Got some quota. Try to acquire writing privilege on the
// transport.
if _, err := wait(s.ctx, nil, nil, t.shutdownChan, t.writableChan); err != nil {
if _, ok := err.(StreamError); ok {
// Return the connection quota back.
t.sendQuotaPool.add(ps)
}
if t.framer.adjustNumWriters(-1) == 0 {
// This writer is the last one in this batch and has the
// responsibility to flush the buffered frames. It queues
// a flush request to controlBuf instead of flushing directly
// in order to avoid the race with other writing or flushing.
t.controlBuf.put(&flushIO{})
}
return err
}
select {
case <-s.ctx.Done():
t.sendQuotaPool.add(ps)
if t.framer.adjustNumWriters(-1) == 0 {
t.controlBuf.put(&flushIO{})
}
t.writableChan <- 0
return ContextErr(s.ctx.Err())
default:
}
var forceFlush bool
if r.Len() == 0 && t.framer.adjustNumWriters(0) == 1 && !opts.Last {
forceFlush = true
}
if err := t.framer.writeData(forceFlush, s.id, false, p); err != nil {
t.Close()
return connectionErrorf(true, err, "transport: %v", err)
}
if t.framer.adjustNumWriters(-1) == 0 {
t.framer.flushWrite()
}
t.writableChan <- 0
}
}
func (t *http2Server) applySettings(ss []http2.Setting) {
for _, s := range ss {
if s.ID == http2.SettingInitialWindowSize {
t.mu.Lock()
defer t.mu.Unlock()
for _, stream := range t.activeStreams {
stream.sendQuotaPool.add(int(s.Val - t.streamSendQuota))
}
t.streamSendQuota = s.Val
}
}
}
// keepalive running in a separate goroutine does the following:
// 1. Gracefully closes an idle connection after a duration of keepalive.MaxConnectionIdle.
// 2. Gracefully closes any connection after a duration of keepalive.MaxConnectionAge.
// 3. Forcibly closes a connection after an additive period of keepalive.MaxConnectionAgeGrace over keepalive.MaxConnectionAge.
// 4. Makes sure a connection is alive by sending pings with a frequency of keepalive.Time and closes a non-resposive connection
// after an additional duration of keepalive.Timeout.
func (t *http2Server) keepalive() {
p := &ping{}
var pingSent bool
maxIdle := time.NewTimer(t.kp.MaxConnectionIdle)
maxAge := time.NewTimer(t.kp.MaxConnectionAge)
keepalive := time.NewTimer(t.kp.Time)
// NOTE: All exit paths of this function should reset their
// respecitve timers. A failure to do so will cause the
// following clean-up to deadlock and eventually leak.
defer func() {
if !maxIdle.Stop() {
<-maxIdle.C
}
if !maxAge.Stop() {
<-maxAge.C
}
if !keepalive.Stop() {
<-keepalive.C
}
}()
for {
select {
case <-maxIdle.C:
t.mu.Lock()
idle := t.idle
if idle.IsZero() { // The connection is non-idle.
t.mu.Unlock()
maxIdle.Reset(t.kp.MaxConnectionIdle)
continue
}
val := t.kp.MaxConnectionIdle - time.Since(idle)
if val <= 0 {
// The connection has been idle for a duration of keepalive.MaxConnectionIdle or more.
// Gracefully close the connection.
t.state = draining
t.mu.Unlock()
t.Drain()
// Reseting the timer so that the clean-up doesn't deadlock.
maxIdle.Reset(infinity)
return
}
t.mu.Unlock()
maxIdle.Reset(val)
case <-maxAge.C:
t.mu.Lock()
t.state = draining
t.mu.Unlock()
t.Drain()
maxAge.Reset(t.kp.MaxConnectionAgeGrace)
select {
case <-maxAge.C:
// Close the connection after grace period.
t.Close()
// Reseting the timer so that the clean-up doesn't deadlock.
maxAge.Reset(infinity)
case <-t.shutdownChan:
}
return
case <-keepalive.C:
if atomic.CompareAndSwapUint32(&t.activity, 1, 0) {
pingSent = false
keepalive.Reset(t.kp.Time)
continue
}
if pingSent {
t.Close()
// Reseting the timer so that the clean-up doesn't deadlock.
keepalive.Reset(infinity)
return
}
pingSent = true
t.controlBuf.put(p)
keepalive.Reset(t.kp.Timeout)
case <-t.shutdownChan:
return
}
}
}
// controller running in a separate goroutine takes charge of sending control
// frames (e.g., window update, reset stream, setting, etc.) to the server.
func (t *http2Server) controller() {
for {
select {
case i := <-t.controlBuf.get():
t.controlBuf.load()
select {
case <-t.writableChan:
switch i := i.(type) {
case *windowUpdate:
t.framer.writeWindowUpdate(true, i.streamID, i.increment)
case *settings:
if i.ack {
t.framer.writeSettingsAck(true)
t.applySettings(i.ss)
} else {
t.framer.writeSettings(true, i.ss...)
}
case *resetStream:
t.framer.writeRSTStream(true, i.streamID, i.code)
case *goAway:
t.mu.Lock()
if t.state == closing {
t.mu.Unlock()
// The transport is closing.
return
}
sid := t.maxStreamID
t.state = draining
t.mu.Unlock()
t.framer.writeGoAway(true, sid, i.code, i.debugData)
if i.code == http2.ErrCodeEnhanceYourCalm {
t.Close()
}
case *flushIO:
t.framer.flushWrite()
case *ping:
t.framer.writePing(true, i.ack, i.data)
default:
grpclog.Printf("transport: http2Server.controller got unexpected item type %v\n", i)
}
t.writableChan <- 0
continue
case <-t.shutdownChan:
return
}
case <-t.shutdownChan:
return
}
}
}
// Close starts shutting down the http2Server transport.
// TODO(zhaoq): Now the destruction is not blocked on any pending streams. This
// could cause some resource issue. Revisit this later.
func (t *http2Server) Close() (err error) {
t.mu.Lock()
if t.state == closing {
t.mu.Unlock()
return errors.New("transport: Close() was already called")
}
t.state = closing
streams := t.activeStreams
t.activeStreams = nil
t.mu.Unlock()
close(t.shutdownChan)
err = t.conn.Close()
// Cancel all active streams.
for _, s := range streams {
s.cancel()
}
if t.stats != nil {
connEnd := &stats.ConnEnd{}
t.stats.HandleConn(t.ctx, connEnd)
}
return
}
// closeStream clears the footprint of a stream when the stream is not needed
// any more.
func (t *http2Server) closeStream(s *Stream) {
t.mu.Lock()
delete(t.activeStreams, s.id)
if len(t.activeStreams) == 0 {
t.idle = time.Now()
}
if t.state == draining && len(t.activeStreams) == 0 {
defer t.Close()
}
t.mu.Unlock()
// In case stream sending and receiving are invoked in separate
// goroutines (e.g., bi-directional streaming), cancel needs to be
// called to interrupt the potential blocking on other goroutines.
s.cancel()
s.mu.Lock()
if q := s.fc.resetPendingData(); q > 0 {
if w := t.fc.onRead(q); w > 0 {
t.controlBuf.put(&windowUpdate{0, w})
}
}
if s.state == streamDone {
s.mu.Unlock()
return
}
s.state = streamDone
s.mu.Unlock()
}
func (t *http2Server) RemoteAddr() net.Addr {
return t.remoteAddr
}
func (t *http2Server) Drain() {
t.controlBuf.put(&goAway{code: http2.ErrCodeNo})
}
var rgen = rand.New(rand.NewSource(time.Now().UnixNano()))
func getJitter(v time.Duration) time.Duration {
if v == infinity {
return 0
}
// Generate a jitter between +/- 10% of the value.
r := int64(v / 10)
j := rgen.Int63n(2*r) - r
return time.Duration(j)
}