Add support for wildcard-sni

go.mod

@@ -3,7 +3,7 @@ module github.com/sagernet/sing-shadowtls
 go 1.20
 
 require (
-	github.com/sagernet/sing v0.6.0
+	github.com/sagernet/sing v0.6.3
 	golang.org/x/crypto v0.32.0
 	golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56
 )

go.sum

@@ -1,7 +1,7 @@
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
-github.com/sagernet/sing v0.6.0 h1:jT55zAXrG7H3x+s/FlrC15xQy3LcmuZ2GGA9+8IJdt0=
+github.com/sagernet/sing v0.6.3 h1:J1spMc6LMlqUvRjWjvNMAcbvACDneqxB9zxfLuS0UTE=
-github.com/sagernet/sing v0.6.0/go.mod h1:ARkL0gM13/Iv5VCZmci/NuoOlePoIsW0m7BWfln/Hak=
+github.com/sagernet/sing v0.6.3/go.mod h1:ARkL0gM13/Iv5VCZmci/NuoOlePoIsW0m7BWfln/Hak=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 golang.org/x/crypto v0.32.0 h1:euUpcYgM8WcP71gNpTqQCn6rC2t6ULUPiOzfWaXVVfc=
 golang.org/x/crypto v0.32.0/go.mod h1:ZnnJkOaASj8g0AjIduWNlq2NRxL0PlBrbKVyZ6V/Ugc=

service.go

@@ -27,10 +27,19 @@ type Service struct {
 	handshake              HandshakeConfig
 	handshakeForServerName map[string]HandshakeConfig
 	strictMode             bool
+	wildcardSNI            WildcardSNI
 	handler                N.TCPConnectionHandlerEx
 	logger                 logger.ContextLogger
 }
 
+type WildcardSNI int
+
+const (
+	WildcardSNIOff WildcardSNI = iota
+	WildcardSNIAuthed
+	WildcardSNIAll
+)
+
 type ServiceConfig struct {
 	Version                int
 	Password               string // for protocol version 2
@@ -38,6 +47,7 @@ type ServiceConfig struct {
 	Handshake              HandshakeConfig
 	HandshakeForServerName map[string]HandshakeConfig // for protocol version 2/3
 	StrictMode             bool                       // for protocol version 3
+	WildcardSNI            WildcardSNI                // for protocol version 3
 	Handler                N.TCPConnectionHandlerEx
 	Logger                 logger.ContextLogger
 }
@@ -60,11 +70,12 @@ func NewService(config ServiceConfig) (*Service, error) {
 		handshake:              config.Handshake,
 		handshakeForServerName: config.HandshakeForServerName,
 		strictMode:             config.StrictMode,
+		wildcardSNI:            config.WildcardSNI,
 		handler:                config.Handler,
 		logger:                 config.Logger,
 	}
 
-	if !service.handshake.Server.IsValid() {
+	if !service.handshake.Server.IsValid() && service.wildcardSNI == WildcardSNIOff {
 		return nil, E.New("missing default handshake information")
 	}
 
@@ -84,16 +95,6 @@ func NewService(config ServiceConfig) (*Service, error) {
 	return service, nil
 }
 
-func (s *Service) selectHandshake(clientHelloFrame *buf.Buffer) HandshakeConfig {
-	serverName, err := extractServerName(clientHelloFrame.Bytes())
-	if err == nil {
-		if customHandshake, found := s.handshakeForServerName[serverName]; found {
-			return customHandshake
-		}
-	}
-	return s.handshake
-}
-
 func (s *Service) NewConnection(ctx context.Context, conn net.Conn, source M.Socksaddr, destination M.Socksaddr, onClose N.CloseHandlerFunc) error {
 	switch s.version {
 	default:
@@ -127,8 +128,17 @@ func (s *Service) NewConnection(ctx context.Context, conn net.Conn, source M.Soc
 		if err != nil {
 			return E.Cause(err, "read client handshake")
 		}
-
+		serverName, err := extractServerName(clientHelloFrame.Bytes())
-		handshakeConfig := s.selectHandshake(clientHelloFrame)
+		var handshakeConfig HandshakeConfig
+		if err == nil {
+			if customHandshake, found := s.handshakeForServerName[serverName]; found {
+				handshakeConfig = customHandshake
+			} else {
+				handshakeConfig = s.handshake
+			}
+		} else {
+			handshakeConfig = s.handshake
+		}
 		handshakeConn, err := handshakeConfig.Dialer.DialContext(ctx, N.NetworkTCP, handshakeConfig.Server)
 		if err != nil {
 			return E.Cause(err, "server handshake")
@@ -154,28 +164,56 @@ func (s *Service) NewConnection(ctx context.Context, conn net.Conn, source M.Soc
 		if err != nil {
 			return E.Cause(err, "read client handshake")
 		}
-
+		defer clientHelloFrame.Release()
-		handshakeConfig := s.selectHandshake(clientHelloFrame)
+		serverName, err := extractServerName(clientHelloFrame.Bytes())
-		handshakeConn, err := handshakeConfig.Dialer.DialContext(ctx, N.NetworkTCP, handshakeConfig.Server)
 		if err != nil {
-			return E.Cause(err, "server handshake")
+			return E.Cause(err, "extract server name")
 		}
-
+		var (
-		_, err = handshakeConn.Write(clientHelloFrame.Bytes())
+			handshakeConfig HandshakeConfig
-		if err != nil {
+			isCustom        bool
-			clientHelloFrame.Release()
+		)
-			return E.Cause(err, "write client handshake")
+		if customHandshake, found := s.handshakeForServerName[serverName]; found {
+			handshakeConfig = customHandshake
+			isCustom = true
+		} else {
+			handshakeConfig = s.handshake
+			if s.wildcardSNI != WildcardSNIOff {
+				handshakeConfig.Server = M.Socksaddr{
+					Fqdn: serverName,
+					Port: 443,
+				}
+			}
 		}
+		var handshakeConn net.Conn
 		user, err := verifyClientHello(clientHelloFrame.Bytes(), s.users)
 		if err != nil {
 			s.logger.WarnContext(ctx, E.Cause(err, "client hello verify failed"))
-			return bufio.CopyConn(ctx, conn, handshakeConn)
+			if s.wildcardSNI == WildcardSNIAll || isCustom {
+				handshakeConn, err = handshakeConfig.Dialer.DialContext(ctx, N.NetworkTCP, handshakeConfig.Server)
+			} else {
+				handshakeConn, err = s.handshake.Dialer.DialContext(ctx, N.NetworkTCP, s.handshake.Server)
+			}
+			if err != nil {
+				return E.Cause(err, "server handshake")
+			}
+			return bufio.CopyConn(ctx, bufio.NewCachedConn(conn, clientHelloFrame), handshakeConn)
 		}
 		if user.Name != "" {
 			ctx = auth.ContextWithUser(ctx, user.Name)
 		}
 		s.logger.TraceContext(ctx, "client hello verify success")
+
+		handshakeConn, err = handshakeConfig.Dialer.DialContext(ctx, N.NetworkTCP, handshakeConfig.Server)
+		if err != nil {
+			return E.Cause(err, "server handshake")
+		}
+
+		_, err = handshakeConn.Write(clientHelloFrame.Bytes())
 		clientHelloFrame.Release()
+		if err != nil {
+			return E.Cause(err, "write client handshake")
+		}
 
 		var serverHelloFrame *buf.Buffer
 		serverHelloFrame, err = extractFrame(handshakeConn)