Simply modify

ctx.go

@@ -576,13 +576,6 @@ func (c *Ctx) SetTLSExtServernameCallback(sni_cb TLSExtServernameCallback) {
 
 type TLSExtAlpnCallback func(ssl *SSL, out unsafe.Pointer, outlen unsafe.Pointer, in unsafe.Pointer, inlen uint, arg unsafe.Pointer) SSLTLSExtErr
 
-// SetTLSExtAlpnCallback sets callback function for Application Layer Protocol Negotiation
-// (ALPN) rfc7301 (https://tools.ietf.org/html/rfc7301).
-func (c *Ctx) SetTLSExtAlpnCallback(alpn_cb TLSExtAlpnCallback, arg unsafe.Pointer) {
-	c.alpn_cb = alpn_cb
-	C.SSL_CTX_set_alpn_select_cb(c.ctx, (*[0]byte)(C.alpn_cb), arg)
-}
-
 func (ctx *Ctx) SetServerALPNProtos(protos []string) {
 	// Construct the protocol list (format: length byte of each protocol + protocol content)
 	var protoList []byte
@@ -591,20 +584,28 @@ func (ctx *Ctx) SetServerALPNProtos(protos []string) {
 		protoList = append(protoList, []byte(proto)...) // Add the protocol content
 	}
 
-	ctx.SetTLSExtAlpnCallback(func(ssl *SSL, out unsafe.Pointer, outlen unsafe.Pointer, in unsafe.Pointer, inlen uint, arg unsafe.Pointer) SSLTLSExtErr {
+	ctx.alpn_cb = func(ssl *SSL, out unsafe.Pointer, outlen unsafe.Pointer, in unsafe.Pointer, inlen uint, arg unsafe.Pointer) SSLTLSExtErr {
 		// Use OpenSSL function to select the protocol
-		ret := ssl.SslSelectNextProto(out, outlen, unsafe.Pointer(&protoList[0]), uint(len(protoList)), in, inlen)
+		ret := C.SSL_select_next_proto(
+			(**C.uchar)(out),
+			(*C.uchar)(outlen),
+			(*C.uchar)(unsafe.Pointer(&protoList[0])),
+			C.uint(len(protoList)),
+			(*C.uchar)(in),
+			C.uint(inlen),
+		)
 
 		if ret != OPENSSL_NPN_NEGOTIATED {
 			return SSLTLSExtErrAlertFatal
 		}
 
 		return SSLTLSExtErrOK
-	}, nil)
+	}
+	C.SSL_CTX_set_alpn_select_cb(ctx.ctx, (*[0]byte)(C.alpn_cb), nil)
 }
 
-// SetALPNProtos sets the ALPN protocol list
-func (ctx *Ctx) SetALPNProtos(protos []string) error {
+// SetClientALPNProtos sets the ALPN protocol list
+func (ctx *Ctx) SetClientALPNProtos(protos []string) error {
 	// Construct the protocol list (format: length byte of each protocol + protocol content)
 	var protoList []byte
 	for _, proto := range protos {

examples/tlcp_client/main.go

@@ -46,7 +46,7 @@ func main() {
 		panic(err)
 	}
 
-	if err := ctx.SetALPNProtos(alpnProtocols); err != nil {
+	if err := ctx.SetClientALPNProtos(alpnProtocols); err != nil {
 		panic(err)
 	}
 

examples/tlcp_server/main.go

@@ -89,7 +89,7 @@ func handleConn(conn net.Conn) {
 	log.Println("Close connection")
 }
 
-func newNTLSServerWithSNI(acceptAddr string, certKeyPairs map[string]crypto.GMDoubleCertKey, cafile string) (net.Listener, error) {
+func newNTLSServer(acceptAddr string, certKeyPairs map[string]crypto.GMDoubleCertKey, cafile string, alpnProtocols []string) (net.Listener, error) {
 
 	ctx, err := ts.NewCtxWithVersion(ts.NTLS)
 	if err != nil {
@@ -103,8 +103,7 @@ func newNTLSServerWithSNI(acceptAddr string, certKeyPairs map[string]crypto.GMDo
 	}
 
 	// Set ALPN
-	supportedProtos := []string{"h2", "http/1.1"}
-	ctx.SetServerALPNProtos(supportedProtos)
+	ctx.SetServerALPNProtos(alpnProtocols)
 
 	// Set SNI callback
 	ctx.SetTLSExtServernameCallback(func(ssl *ts.SSL) ts.SSLTLSExtErr {
@@ -304,7 +303,7 @@ func main() {
 		return
 	}
 
-	server, err := newNTLSServerWithSNI(acceptAddr, certFiles, caFile)
+	server, err := newNTLSServer(acceptAddr, certFiles, caFile, alpnProtocols)
 	if err != nil {
 		return
 	}

ntls_test.go

@@ -1000,7 +1000,7 @@ func TestALPN(t *testing.T) {
 	}
 
 	// Set the ALPN protocols for the context
-	if err := ctx.SetALPNProtos(alpnProtocols); err != nil {
+	if err := ctx.SetClientALPNProtos(alpnProtocols); err != nil {
 		t.Error(err)
 		return
 	}

ssl.go

@@ -192,19 +192,3 @@ func alpn_cb_thunk(p unsafe.Pointer, con *C.SSL, out unsafe.Pointer, outlen unsa
 	// Ensure the out parameter is treated as a pointer to const unsigned char
 	return C.int(alpn_cb(s, out, outlen, in, inlen, arg))
 }
-
-// SslSelectNextProto selects the next protocol from the list of protocols
-// provided by the server and the client's list of supported protocols.
-// It takes pointers to the output buffer, output length, server buffer,
-// server length, input buffer, and input length as parameters. The function
-// returns an integer indicating the result of the selection process.
-func (s *SSL) SslSelectNextProto(out unsafe.Pointer, outlen unsafe.Pointer, server unsafe.Pointer, serverlen uint, in unsafe.Pointer, inlen uint) C.int {
-	return C.SSL_select_next_proto(
-		(**C.uchar)(out),
-		(*C.uchar)(outlen),
-		(*C.uchar)(server),
-		C.uint(serverlen),
-		(*C.uchar)(in),
-		C.uint(inlen),
-	)
-}