http2: server advertises SETTINGS_ENABLE_CONNECT_PROTOCOL support

WeidiDeng · WeidiDeng · commit d1683ac987d8 · 2024-09-09T16:38:23.000+08:00
diff --git a/http2/frame.go b/http2/frame.go
@@ -1490,7 +1490,7 @@ func (mh *MetaHeadersFrame) checkPseudos() error {
 	pf := mh.PseudoFields()
 	for i, hf := range pf {
 		switch hf.Name {
-		case ":method", ":path", ":scheme", ":authority":
+		case ":method", ":path", ":scheme", ":authority", ":protocol":
 			isRequest = true
 		case ":status":
 			isResponse = true
diff --git a/http2/http2.go b/http2/http2.go
@@ -33,10 +33,11 @@ import (
 )
 
 var (
-	VerboseLogs    bool
-	logFrameWrites bool
-	logFrameReads  bool
-	inTests        bool
+	VerboseLogs                    bool
+	logFrameWrites                 bool
+	logFrameReads                  bool
+	inTests                        bool
+	disableExtendedConnectProtocol bool
 )
 
 func init() {
@@ -49,6 +50,9 @@ func init() {
 		logFrameWrites = true
 		logFrameReads = true
 	}
+	if strings.Contains(e, "http2xconnect=0") {
+		disableExtendedConnectProtocol = true
+	}
 }
 
 const (
@@ -149,21 +153,23 @@ func (s Setting) Valid() error {
 type SettingID uint16
 
 const (
-	SettingHeaderTableSize      SettingID = 0x1
-	SettingEnablePush           SettingID = 0x2
-	SettingMaxConcurrentStreams SettingID = 0x3
-	SettingInitialWindowSize    SettingID = 0x4
-	SettingMaxFrameSize         SettingID = 0x5
-	SettingMaxHeaderListSize    SettingID = 0x6
+	SettingHeaderTableSize       SettingID = 0x1
+	SettingEnablePush            SettingID = 0x2
+	SettingMaxConcurrentStreams  SettingID = 0x3
+	SettingInitialWindowSize     SettingID = 0x4
+	SettingMaxFrameSize          SettingID = 0x5
+	SettingMaxHeaderListSize     SettingID = 0x6
+	SettingEnableConnectProtocol SettingID = 0x8
 )
 
 var settingName = map[SettingID]string{
-	SettingHeaderTableSize:      "HEADER_TABLE_SIZE",
-	SettingEnablePush:           "ENABLE_PUSH",
-	SettingMaxConcurrentStreams: "MAX_CONCURRENT_STREAMS",
-	SettingInitialWindowSize:    "INITIAL_WINDOW_SIZE",
-	SettingMaxFrameSize:         "MAX_FRAME_SIZE",
-	SettingMaxHeaderListSize:    "MAX_HEADER_LIST_SIZE",
+	SettingHeaderTableSize:       "HEADER_TABLE_SIZE",
+	SettingEnablePush:            "ENABLE_PUSH",
+	SettingMaxConcurrentStreams:  "MAX_CONCURRENT_STREAMS",
+	SettingInitialWindowSize:     "INITIAL_WINDOW_SIZE",
+	SettingMaxFrameSize:          "MAX_FRAME_SIZE",
+	SettingMaxHeaderListSize:     "MAX_HEADER_LIST_SIZE",
+	SettingEnableConnectProtocol: "ENABLE_CONNECT_PROTOCOL",
 }
 
 func (s SettingID) String() string {
diff --git a/http2/server.go b/http2/server.go
@@ -935,14 +935,18 @@ func (sc *serverConn) serve() {
 		sc.vlogf("http2: server connection from %v on %p", sc.conn.RemoteAddr(), sc.hs)
 	}
 
+	settings := writeSettings{
+		{SettingMaxFrameSize, sc.srv.maxReadFrameSize()},
+		{SettingMaxConcurrentStreams, sc.advMaxStreams},
+		{SettingMaxHeaderListSize, sc.maxHeaderListSize()},
+		{SettingHeaderTableSize, sc.srv.maxDecoderHeaderTableSize()},
+		{SettingInitialWindowSize, uint32(sc.srv.initialStreamRecvWindowSize())},
+	}
+	if !disableExtendedConnectProtocol {
+		settings = append(settings, Setting{SettingEnableConnectProtocol, 1})
+	}
 	sc.writeFrame(FrameWriteRequest{
-		write: writeSettings{
-			{SettingMaxFrameSize, sc.srv.maxReadFrameSize()},
-			{SettingMaxConcurrentStreams, sc.advMaxStreams},
-			{SettingMaxHeaderListSize, sc.maxHeaderListSize()},
-			{SettingHeaderTableSize, sc.srv.maxDecoderHeaderTableSize()},
-			{SettingInitialWindowSize, uint32(sc.srv.initialStreamRecvWindowSize())},
-		},
+		write: settings,
 	})
 	sc.unackedSettings++
 
@@ -1757,6 +1761,9 @@ func (sc *serverConn) processSetting(s Setting) error {
 		sc.maxFrameSize = int32(s.Val) // the maximum valid s.Val is < 2^31
 	case SettingMaxHeaderListSize:
 		sc.peerMaxHeaderListSize = s.Val
+	case SettingEnableConnectProtocol:
+		// Receipt of this parameter by a server does not
+		// have any impact
 	default:
 		// Unknown setting: "An endpoint that receives a SETTINGS
 		// frame with any unknown or unsupported identifier MUST
@@ -2187,11 +2194,17 @@ func (sc *serverConn) newWriterAndRequest(st *stream, f *MetaHeadersFrame) (*res
 		scheme:    f.PseudoValue("scheme"),
 		authority: f.PseudoValue("authority"),
 		path:      f.PseudoValue("path"),
+		protocol:  f.PseudoValue("protocol"),
+	}
+
+	// extended connect is disabled, so we should not see :protocol
+	if disableExtendedConnectProtocol && rp.protocol != "" {
+		return nil, nil, sc.countError("bad_connect", streamError(f.StreamID, ErrCodeProtocol))
 	}
 
 	isConnect := rp.method == "CONNECT"
 	if isConnect {
-		if rp.path != "" || rp.scheme != "" || rp.authority == "" {
+		if rp.protocol == "" && (rp.path != "" || rp.scheme != "" || rp.authority == "") {
 			return nil, nil, sc.countError("bad_connect", streamError(f.StreamID, ErrCodeProtocol))
 		}
 	} else if rp.method == "" || rp.path == "" || (rp.scheme != "https" && rp.scheme != "http") {
@@ -2215,6 +2228,9 @@ func (sc *serverConn) newWriterAndRequest(st *stream, f *MetaHeadersFrame) (*res
 	if rp.authority == "" {
 		rp.authority = rp.header.Get("Host")
 	}
+	if rp.protocol != "" {
+		rp.header.Set(":protocol", rp.protocol)
+	}
 
 	rw, req, err := sc.newWriterAndRequestNoBody(st, rp)
 	if err != nil {
@@ -2241,6 +2257,7 @@ func (sc *serverConn) newWriterAndRequest(st *stream, f *MetaHeadersFrame) (*res
 type requestParam struct {
 	method                  string
 	scheme, authority, path string
+	protocol                string
 	header                  http.Header
 }
 
@@ -2282,7 +2299,7 @@ func (sc *serverConn) newWriterAndRequestNoBody(st *stream, rp requestParam) (*r
 
 	var url_ *url.URL
 	var requestURI string
-	if rp.method == "CONNECT" {
+	if rp.method == "CONNECT" && rp.protocol == "" {
 		url_ = &url.URL{Host: rp.authority}
 		requestURI = rp.authority // mimic HTTP/1 server behavior
 	} else {
