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/*
*
* 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"
"net"
"strconv"
"sync"
"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/metadata"
)
// 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 {
conn net.Conn
maxStreamID uint32 // max stream ID ever seen
authInfo credentials.AuthInfo // auth info about the connection
// writableChan synchronizes write access to the transport.
// A writer acquires the write lock by sending a value on writableChan
// and releases it by receiving from 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
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
}
// newHTTP2Server constructs a ServerTransport based on HTTP2. ConnectionError is
// returned if something goes wrong.
func newHTTP2Server(conn net.Conn, maxStreams uint32, authInfo credentials.AuthInfo) (_ 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.
if maxStreams == 0 {
maxStreams = math.MaxUint32
} else {
settings = append(settings, http2.Setting{http2.SettingMaxConcurrentStreams, maxStreams})
}
if initialWindowSize != defaultWindowSize {
settings = append(settings, http2.Setting{http2.SettingInitialWindowSize, uint32(initialWindowSize)})
}
if err := framer.writeSettings(true, settings...); err != nil {
return nil, ConnectionErrorf("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("transport: %v", err)
}
}
var buf bytes.Buffer
t := &http2Server{
conn: conn,
authInfo: authInfo,
framer: framer,
hBuf: &buf,
hEnc: hpack.NewEncoder(&buf),
maxStreams: maxStreams,
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,
}
go t.controller()
t.writableChan <- 0
return t, nil
}
// operateHeader takes action on the decoded headers. It returns the current
// stream if there are remaining headers on the wire (in the following
// Continuation frame).
func (t *http2Server) operateHeaders(hDec *hpackDecoder, s *Stream, frame headerFrame, endStream bool, handle func(*Stream)) (pendingStream *Stream) {
defer func() {
if pendingStream == nil {
hDec.state = decodeState{}
}
}()
endHeaders, err := hDec.decodeServerHTTP2Headers(frame)
if s == nil {
// s has been closed.
return nil
}
if err != nil {
grpclog.Printf("transport: http2Server.operateHeader found %v", err)
if se, ok := err.(StreamError); ok {
t.controlBuf.put(&resetStream{s.id, statusCodeConvTab[se.Code]})
}
return nil
}
if endStream {
// s is just created by the caller. No lock needed.
s.state = streamReadDone
}
if !endHeaders {
return s
}
t.mu.Lock()
if t.state != reachable {
t.mu.Unlock()
return nil
}
if uint32(len(t.activeStreams)) >= t.maxStreams {
t.mu.Unlock()
t.controlBuf.put(&resetStream{s.id, http2.ErrCodeRefusedStream})
return nil
}
s.sendQuotaPool = newQuotaPool(int(t.streamSendQuota))
t.activeStreams[s.id] = s
t.mu.Unlock()
s.windowHandler = func(n int) {
t.updateWindow(s, uint32(n))
}
if hDec.state.timeoutSet {
s.ctx, s.cancel = context.WithTimeout(context.TODO(), hDec.state.timeout)
} else {
s.ctx, s.cancel = context.WithCancel(context.TODO())
}
// Attach Auth info if there is any.
if t.authInfo != nil {
s.ctx = credentials.NewContext(s.ctx, t.authInfo)
}
// 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(hDec.state.mdata) > 0 {
s.ctx = metadata.NewContext(s.ctx, hDec.state.mdata)
}
s.dec = &recvBufferReader{
ctx: s.ctx,
recv: s.buf,
}
s.method = hDec.state.method
handle(s)
return nil
}
// HandleStreams receives incoming streams using the given handler. This is
// typically run in a separate goroutine.
func (t *http2Server) HandleStreams(handle func(*Stream)) {
// 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 != nil {
grpclog.Printf("transport: http2Server.HandleStreams failed to read frame: %v", err)
t.Close()
return
}
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)
hDec := newHPACKDecoder()
var curStream *Stream
for {
frame, err := t.framer.readFrame()
if err != nil {
t.Close()
return
}
switch frame := frame.(type) {
case *http2.HeadersFrame:
id := frame.Header().StreamID
if id%2 != 1 || id <= t.maxStreamID {
// illegal gRPC stream id.
grpclog.Println("transport: http2Server.HandleStreams received an illegal stream id: ", id)
t.Close()
break
}
t.maxStreamID = id
buf := newRecvBuffer()
fc := &inFlow{
limit: initialWindowSize,
conn: t.fc,
}
curStream = &Stream{
id: frame.Header().StreamID,
st: t,
buf: buf,
fc: fc,
}
endStream := frame.Header().Flags.Has(http2.FlagHeadersEndStream)
curStream = t.operateHeaders(hDec, curStream, frame, endStream, handle)
case *http2.ContinuationFrame:
curStream = t.operateHeaders(hDec, curStream, frame, false, handle)
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:
break
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) {
swu, cwu := s.fc.onRead(n)
if swu > 0 {
t.controlBuf.put(&windowUpdate{s.id, swu})
}
if cwu > 0 {
t.controlBuf.put(&windowUpdate{0, cwu})
}
}
func (t *http2Server) handleData(f *http2.DataFrame) {
// Select the right stream to dispatch.
s, ok := t.getStream(f)
if !ok {
return
}
size := len(f.Data())
if size > 0 {
if err := s.fc.onData(uint32(size)); err != nil {
if _, ok := err.(ConnectionError); ok {
grpclog.Printf("transport: http2Server %v", err)
t.Close()
return
}
t.closeStream(s)
t.controlBuf.put(&resetStream{s.id, http2.ErrCodeFlowControl})
return
}
// 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?
data := make([]byte, size)
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 {
if s.state == streamWriteDone {
s.state = streamDone
} else {
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})
}
func (t *http2Server) handlePing(f *http2.PingFrame) {
t.controlBuf.put(&ping{true})
}
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
// 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("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
s.mu.Unlock()
if _, err := wait(s.ctx, 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"})
for k, v := range md {
for _, entry := range v {
t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
}
}
if err := t.writeHeaders(s, t.hBuf, false); err != nil {
return err
}
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, statusCode codes.Code, statusDesc string) error {
var headersSent bool
s.mu.Lock()
if s.state == streamDone {
s.mu.Unlock()
return nil
}
if s.headerOk {
headersSent = true
}
s.mu.Unlock()
if _, err := wait(s.ctx, 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(statusCode)),
})
t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-message", Value: statusDesc})
// Attach the trailer metadata.
for k, v := range s.trailer {
for _, entry := range v {
t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
}
}
if err := t.writeHeaders(s, t.hBuf, true); err != nil {
t.Close()
return err
}
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) error {
// TODO(zhaoq): Support multi-writers for a single stream.
var writeHeaderFrame bool
s.mu.Lock()
if !s.headerOk {
writeHeaderFrame = true
s.headerOk = true
}
s.mu.Unlock()
if writeHeaderFrame {
if _, err := wait(s.ctx, 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"})
p := http2.HeadersFrameParam{
StreamID: s.id,
BlockFragment: t.hBuf.Bytes(),
EndHeaders: true,
}
if err := t.framer.writeHeaders(false, p); err != nil {
t.Close()
return ConnectionErrorf("transport: %v", err)
}
t.writableChan <- 0
}
r := bytes.NewBuffer(data)
for {
if r.Len() == 0 {
return nil
}
size := http2MaxFrameLen
s.sendQuotaPool.add(0)
// Wait until the stream has some quota to send the data.
sq, err := wait(s.ctx, t.shutdownChan, s.sendQuotaPool.acquire())
if err != nil {
return err
}
t.sendQuotaPool.add(0)
// Wait until the transport has some quota to send the data.
tq, err := wait(s.ctx, t.shutdownChan, t.sendQuotaPool.acquire())
if err != nil {
if _, ok := err.(StreamError); ok {
t.sendQuotaPool.cancel()
}
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, t.shutdownChan, t.writableChan); err != nil {
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
}
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("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.reset(int(s.Val - t.streamSendQuota))
}
t.streamSendQuota = s.Val
}
}
}
// 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 *flushIO:
t.framer.flushWrite()
case *ping:
// TODO(zhaoq): Ack with all-0 data now. will change to some
// meaningful content when this is actually in use.
t.framer.writePing(true, i.ack, [8]byte{})
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()
// Notify all active streams.
for _, s := range streams {
s.write(recvMsg{err: ErrConnClosing})
}
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)
t.mu.Unlock()
if q := s.fc.restoreConn(); q > 0 {
t.controlBuf.put(&windowUpdate{0, q})
}
s.mu.Lock()
if s.state == streamDone {
s.mu.Unlock()
return
}
s.state = streamDone
s.mu.Unlock()
// In case stream sending and receiving are invoked in separate
// goroutines (e.g., bi-directional streaming), the caller needs
// to call cancel on the stream to interrupt the blocking on
// other goroutines.
s.cancel()
}
func (t *http2Server) RemoteAddr() net.Addr {
return t.conn.RemoteAddr()
}