Use h2c from x/net to handle h2c requests

Co-authored-by: Mathieu Lonjaret <mathieu.lonjaret@gmail.com>

vendor/golang.org/x/net/http2/server.go

@@ -28,6 +28,7 @@ package http2
 import (
 	"bufio"
 	"bytes"
+	"context"
 	"crypto/tls"
 	"errors"
 	"fmt"
@@ -209,12 +210,14 @@ func ConfigureServer(s *http.Server, conf *Server) error {
 		conf = new(Server)
 	}
 	conf.state = &serverInternalState{activeConns: make(map[*serverConn]struct{})}
-	if err := configureServer18(s, conf); err != nil {
-		return err
-	}
-	if err := configureServer19(s, conf); err != nil {
-		return err
+	if h1, h2 := s, conf; h2.IdleTimeout == 0 {
+		if h1.IdleTimeout != 0 {
+			h2.IdleTimeout = h1.IdleTimeout
+		} else {
+			h2.IdleTimeout = h1.ReadTimeout
+		}
 	}
+	s.RegisterOnShutdown(conf.state.startGracefulShutdown)
 
 	if s.TLSConfig == nil {
 		s.TLSConfig = new(tls.Config)
@@ -270,7 +273,20 @@ func ConfigureServer(s *http.Server, conf *Server) error {
 		if testHookOnConn != nil {
 			testHookOnConn()
 		}
+		// The TLSNextProto interface predates contexts, so
+		// the net/http package passes down its per-connection
+		// base context via an exported but unadvertised
+		// method on the Handler. This is for internal
+		// net/http<=>http2 use only.
+		var ctx context.Context
+		type baseContexter interface {
+			BaseContext() context.Context
+		}
+		if bc, ok := h.(baseContexter); ok {
+			ctx = bc.BaseContext()
+		}
 		conf.ServeConn(c, &ServeConnOpts{
+			Context:    ctx,
 			Handler:    h,
 			BaseConfig: hs,
 		})
@@ -281,6 +297,10 @@ func ConfigureServer(s *http.Server, conf *Server) error {
 
 // ServeConnOpts are options for the Server.ServeConn method.
 type ServeConnOpts struct {
+	// Context is the base context to use.
+	// If nil, context.Background is used.
+	Context context.Context
+
 	// BaseConfig optionally sets the base configuration
 	// for values. If nil, defaults are used.
 	BaseConfig *http.Server
@@ -291,6 +311,13 @@ type ServeConnOpts struct {
 	Handler http.Handler
 }
 
+func (o *ServeConnOpts) context() context.Context {
+	if o.Context != nil {
+		return o.Context
+	}
+	return context.Background()
+}
+
 func (o *ServeConnOpts) baseConfig() *http.Server {
 	if o != nil && o.BaseConfig != nil {
 		return o.BaseConfig
@@ -435,6 +462,15 @@ func (s *Server) ServeConn(c net.Conn, opts *ServeConnOpts) {
 	sc.serve()
 }
 
+func serverConnBaseContext(c net.Conn, opts *ServeConnOpts) (ctx context.Context, cancel func()) {
+	ctx, cancel = context.WithCancel(opts.context())
+	ctx = context.WithValue(ctx, http.LocalAddrContextKey, c.LocalAddr())
+	if hs := opts.baseConfig(); hs != nil {
+		ctx = context.WithValue(ctx, http.ServerContextKey, hs)
+	}
+	return
+}
+
 func (sc *serverConn) rejectConn(err ErrCode, debug string) {
 	sc.vlogf("http2: server rejecting conn: %v, %s", err, debug)
 	// ignoring errors. hanging up anyway.
@@ -450,7 +486,7 @@ type serverConn struct {
 	conn             net.Conn
 	bw               *bufferedWriter // writing to conn
 	handler          http.Handler
-	baseCtx          contextContext
+	baseCtx          context.Context
 	framer           *Framer
 	doneServing      chan struct{}          // closed when serverConn.serve ends
 	readFrameCh      chan readFrameResult   // written by serverConn.readFrames
@@ -530,7 +566,7 @@ type stream struct {
 	id        uint32
 	body      *pipe       // non-nil if expecting DATA frames
 	cw        closeWaiter // closed wait stream transitions to closed state
-	ctx       contextContext
+	ctx       context.Context
 	cancelCtx func()
 
 	// owned by serverConn's serve loop:
@@ -663,6 +699,7 @@ func (sc *serverConn) condlogf(err error, format string, args ...interface{}) {
 
 func (sc *serverConn) canonicalHeader(v string) string {
 	sc.serveG.check()
+	buildCommonHeaderMapsOnce()
 	cv, ok := commonCanonHeader[v]
 	if ok {
 		return cv
@@ -1109,7 +1146,7 @@ func (sc *serverConn) startFrameWrite(wr FrameWriteRequest) {
 
 // errHandlerPanicked is the error given to any callers blocked in a read from
 // Request.Body when the main goroutine panics. Since most handlers read in the
-// the main ServeHTTP goroutine, this will show up rarely.
+// main ServeHTTP goroutine, this will show up rarely.
 var errHandlerPanicked = errors.New("http2: handler panicked")
 
 // wroteFrame is called on the serve goroutine with the result of
@@ -1487,6 +1524,12 @@ func (sc *serverConn) processSettings(f *SettingsFrame) error {
 		}
 		return nil
 	}
+	if f.NumSettings() > 100 || f.HasDuplicates() {
+		// This isn't actually in the spec, but hang up on
+		// suspiciously large settings frames or those with
+		// duplicate entries.
+		return ConnectionError(ErrCodeProtocol)
+	}
 	if err := f.ForeachSetting(sc.processSetting); err != nil {
 		return err
 	}
@@ -1721,6 +1764,13 @@ func (sc *serverConn) processHeaders(f *MetaHeadersFrame) error {
 			// processing this frame.
 			return nil
 		}
+		// RFC 7540, sec 5.1: If an endpoint receives additional frames, other than
+		// WINDOW_UPDATE, PRIORITY, or RST_STREAM, for a stream that is in
+		// this state, it MUST respond with a stream error (Section 5.4.2) of
+		// type STREAM_CLOSED.
+		if st.state == stateHalfClosedRemote {
+			return streamError(id, ErrCodeStreamClosed)
+		}
 		return st.processTrailerHeaders(f)
 	}
 
@@ -1862,7 +1912,7 @@ func (sc *serverConn) newStream(id, pusherID uint32, state streamState) *stream
 		panic("internal error: cannot create stream with id 0")
 	}
 
-	ctx, cancelCtx := contextWithCancel(sc.baseCtx)
+	ctx, cancelCtx := context.WithCancel(sc.baseCtx)
 	st := &stream{
 		sc:        sc,
 		id:        id,
@@ -2028,7 +2078,7 @@ func (sc *serverConn) newWriterAndRequestNoBody(st *stream, rp requestParam) (*r
 		Body:       body,
 		Trailer:    trailer,
 	}
-	req = requestWithContext(req, st.ctx)
+	req = req.WithContext(st.ctx)
 
 	rws := responseWriterStatePool.Get().(*responseWriterState)
 	bwSave := rws.bw
@@ -2056,7 +2106,7 @@ func (sc *serverConn) runHandler(rw *responseWriter, req *http.Request, handler
 				stream: rw.rws.stream,
 			})
 			// Same as net/http:
-			if shouldLogPanic(e) {
+			if e != nil && e != http.ErrAbortHandler {
 				const size = 64 << 10
 				buf := make([]byte, size)
 				buf = buf[:runtime.Stack(buf, false)]
@@ -2281,7 +2331,16 @@ type chunkWriter struct{ rws *responseWriterState }
 
 func (cw chunkWriter) Write(p []byte) (n int, err error) { return cw.rws.writeChunk(p) }
 
-func (rws *responseWriterState) hasTrailers() bool { return len(rws.trailers) != 0 }
+func (rws *responseWriterState) hasTrailers() bool { return len(rws.trailers) > 0 }
+
+func (rws *responseWriterState) hasNonemptyTrailers() bool {
+	for _, trailer := range rws.trailers {
+		if _, ok := rws.handlerHeader[trailer]; ok {
+			return true
+		}
+	}
+	return false
+}
 
 // declareTrailer is called for each Trailer header when the
 // response header is written. It notes that a header will need to be
@@ -2327,15 +2386,7 @@ func (rws *responseWriterState) writeChunk(p []byte) (n int, err error) {
 		}
 		_, hasContentType := rws.snapHeader["Content-Type"]
 		if !hasContentType && bodyAllowedForStatus(rws.status) && len(p) > 0 {
-			if cto := rws.snapHeader.Get("X-Content-Type-Options"); strings.EqualFold("nosniff", cto) {
-				// nosniff is an explicit directive not to guess a content-type.
-				// Content-sniffing is no less susceptible to polyglot attacks via
-				// hosted content when done on the server.
-				ctype = "application/octet-stream"
-				rws.conn.logf("http2: WriteHeader called with X-Content-Type-Options:nosniff but no Content-Type")
-			} else {
-				ctype = http.DetectContentType(p)
-			}
+			ctype = http.DetectContentType(p)
 		}
 		var date string
 		if _, ok := rws.snapHeader["Date"]; !ok {
@@ -2347,6 +2398,19 @@ func (rws *responseWriterState) writeChunk(p []byte) (n int, err error) {
 			foreachHeaderElement(v, rws.declareTrailer)
 		}
 
+		// "Connection" headers aren't allowed in HTTP/2 (RFC 7540, 8.1.2.2),
+		// but respect "Connection" == "close" to mean sending a GOAWAY and tearing
+		// down the TCP connection when idle, like we do for HTTP/1.
+		// TODO: remove more Connection-specific header fields here, in addition
+		// to "Connection".
+		if _, ok := rws.snapHeader["Connection"]; ok {
+			v := rws.snapHeader.Get("Connection")
+			delete(rws.snapHeader, "Connection")
+			if v == "close" {
+				rws.conn.startGracefulShutdown()
+			}
+		}
+
 		endStream := (rws.handlerDone && !rws.hasTrailers() && len(p) == 0) || isHeadResp
 		err = rws.conn.writeHeaders(rws.stream, &writeResHeaders{
 			streamID:      rws.stream.id,
@@ -2376,7 +2440,10 @@ func (rws *responseWriterState) writeChunk(p []byte) (n int, err error) {
 		rws.promoteUndeclaredTrailers()
 	}
 
-	endStream := rws.handlerDone && !rws.hasTrailers()
+	// only send trailers if they have actually been defined by the
+	// server handler.
+	hasNonemptyTrailers := rws.hasNonemptyTrailers()
+	endStream := rws.handlerDone && !hasNonemptyTrailers
 	if len(p) > 0 || endStream {
 		// only send a 0 byte DATA frame if we're ending the stream.
 		if err := rws.conn.writeDataFromHandler(rws.stream, p, endStream); err != nil {
@@ -2385,7 +2452,7 @@ func (rws *responseWriterState) writeChunk(p []byte) (n int, err error) {
 		}
 	}
 
-	if rws.handlerDone && rws.hasTrailers() {
+	if rws.handlerDone && hasNonemptyTrailers {
 		err = rws.conn.writeHeaders(rws.stream, &writeResHeaders{
 			streamID:  rws.stream.id,
 			h:         rws.handlerHeader,
@@ -2613,14 +2680,9 @@ var (
 	ErrPushLimitReached = errors.New("http2: push would exceed peer's SETTINGS_MAX_CONCURRENT_STREAMS")
 )
 
-// pushOptions is the internal version of http.PushOptions, which we
-// cannot include here because it's only defined in Go 1.8 and later.
-type pushOptions struct {
-	Method string
-	Header http.Header
-}
+var _ http.Pusher = (*responseWriter)(nil)
 
-func (w *responseWriter) push(target string, opts pushOptions) error {
+func (w *responseWriter) Push(target string, opts *http.PushOptions) error {
 	st := w.rws.stream
 	sc := st.sc
 	sc.serveG.checkNotOn()
@@ -2631,6 +2693,10 @@ func (w *responseWriter) push(target string, opts pushOptions) error {
 		return ErrRecursivePush
 	}
 
+	if opts == nil {
+		opts = new(http.PushOptions)
+	}
+
 	// Default options.
 	if opts.Method == "" {
 		opts.Method = "GET"