From 1fd13df6ac5421919829c8e02c425c5b1d2ef516 Mon Sep 17 00:00:00 2001
From: wujunzhuo <wujunzhuo@hotmail.com>
Date: Fri, 4 Nov 2022 22:59:41 +0800
Subject: [PATCH] feat: version negotiation between server and client (#390)

---
 core/client.go           |  2 +-
 core/listener_default.go |  2 +-
 core/server.go           | 21 +++++++++++++++++++++
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/core/client.go b/core/client.go
index c7ceaeff2..1982c4a52 100644
--- a/core/client.go
+++ b/core/client.go
@@ -346,7 +346,7 @@ func (c *Client) initOptions() error {
 	// quic config
 	if c.opts.QuicConfig == nil {
 		c.opts.QuicConfig = &quic.Config{
-			Versions:                       []quic.VersionNumber{quic.Version1, quic.VersionDraft29},
+			Versions:                       []quic.VersionNumber{quic.Version2},
 			MaxIdleTimeout:                 time.Second * 40,
 			KeepAlivePeriod:                time.Second * 20,
 			MaxIncomingStreams:             1000,
diff --git a/core/listener_default.go b/core/listener_default.go
index 5bdb1c470..e926cf7a8 100644
--- a/core/listener_default.go
+++ b/core/listener_default.go
@@ -19,7 +19,7 @@ type defaultListener struct {
 
 // DefalutQuicConfig be used when `quicConfig` is nil.
 var DefalutQuicConfig = &quic.Config{
-	Versions:                       []quic.VersionNumber{quic.Version1, quic.VersionDraft29},
+	Versions:                       []quic.VersionNumber{quic.Version2, quic.Version1, quic.VersionDraft29},
 	MaxIdleTimeout:                 time.Second * 5,
 	KeepAlivePeriod:                time.Second * 2,
 	MaxIncomingStreams:             1000,
diff --git a/core/server.go b/core/server.go
index 69daff318..ec3313a56 100644
--- a/core/server.go
+++ b/core/server.go
@@ -40,6 +40,7 @@ type Server struct {
 	connector               Connector
 	router                  Router
 	metadataBuilder         MetadataBuilder
+	alpnHandler             func(proto string) error
 	counterOfDataFrame      int64
 	downstreams             map[string]*Client
 	mu                      sync.Mutex
@@ -121,6 +122,12 @@ func (s *Server) Serve(ctx context.Context, conn net.PacketConn) error {
 			logger.Errorf("%slistener accept connections error: %v", ServerLogPrefix, err)
 			return err
 		}
+		err = s.alpnHandler(conn.ConnectionState().TLS.NegotiatedProtocol)
+		if err != nil {
+			conn.CloseWithError(quic.ApplicationErrorCode(yerr.ErrorCodeRejected), err.Error())
+			continue
+		}
+
 		// connection close handlers on server shutdown
 		// defer s.doConnectionCloseHandlers(conn)
 		s.wg.Add(1)
@@ -485,6 +492,14 @@ func (s *Server) ConfigMetadataBuilder(builder MetadataBuilder) {
 	s.mu.Unlock()
 }
 
+// ConfigAlpnHandler is used to set alpnHandler by zipper
+func (s *Server) ConfigAlpnHandler(h func(string) error) {
+	s.mu.Lock()
+	s.alpnHandler = h
+	logger.Debugf("%sconfig alpnHandler is %#v", ServerLogPrefix, h)
+	s.mu.Unlock()
+}
+
 // AddDownstreamServer add a downstream server to this server. all the DataFrames will be
 // dispatch to all the downstreams.
 func (s *Server) AddDownstreamServer(addr string, c *Client) {
@@ -508,6 +523,12 @@ func GetConnID(conn quic.Connection) string {
 
 func (s *Server) initOptions() {
 	// defaults
+	if s.alpnHandler == nil {
+		s.alpnHandler = func(proto string) error {
+			logger.Infof("%sclient alpn proto is: %s", ServerLogPrefix, proto)
+			return nil
+		}
+	}
 }
 
 func (s *Server) validateRouter() error {