diff --git a/maker/golang/main.go b/maker/golang/main.go
index 142c55f..a2a26bd 100644
--- a/maker/golang/main.go
+++ b/maker/golang/main.go
@@ -283,13 +283,13 @@ func testSearch() {
 	versionNo := binary.LittleEndian.Uint16(header[0:])
 	if versionNo == 2 {
 		// old xdb file
-		version = xdb.V4
+		version = xdb.IPv4
 	} else if versionNo == 3 {
 		ipNo := int(binary.LittleEndian.Uint16(header[16:]))
-		if ipNo == xdb.V4.Id {
-			version = xdb.V4
-		} else if ipNo == xdb.V6.Id {
-			version = xdb.V6
+		if ipNo == xdb.IPv4.Id {
+			version = xdb.IPv4
+		} else if ipNo == xdb.IPv6.Id {
+			version = xdb.IPv6
 		} else {
 			slog.Error("invalid ip version", "id", ipNo)
 			return
diff --git a/maker/golang/xdb/version.go b/maker/golang/xdb/version.go
index 0465fce..bf9c672 100644
--- a/maker/golang/xdb/version.go
+++ b/maker/golang/xdb/version.go
@@ -9,6 +9,11 @@ import (
 	"strings"
 )
 
+const (
+	IPv4VersionNo = 4
+	IPv6VersionNo = 6
+)
+
 type Version struct {
 	Id               int
 	Name             string
@@ -17,14 +22,14 @@ type Version struct {
 }
 
 var (
-	VX = &Version{}
-	V4 = &Version{
+	IPvx = &Version{}
+	IPv4 = &Version{
 		Id:               4,
 		Name:             "IPv4",
 		Bytes:            4,
 		SegmentIndexSize: 14, // 4 + 4 + 2 + 4
 	}
-	V6 = &Version{
+	IPv6 = &Version{
 		Id:               6,
 		Name:             "IPv6",
 		Bytes:            16,
@@ -35,23 +40,23 @@ var (
 func VersionFromIP(ip string) (*Version, error) {
 	bytes, err := ParseIP(ip)
 	if err != nil {
-		return VX, fmt.Errorf("parse ip fail: %w", err)
+		return IPvx, fmt.Errorf("parse ip fail: %w", err)
 	}
 
 	if len(bytes) == 4 {
-		return V4, nil
+		return IPv4, nil
 	}
 
-	return V6, nil
+	return IPv6, nil
 }
 
 func VersionFromName(name string) (*Version, error) {
 	switch strings.ToUpper(name) {
 	case "V4", "IPV4":
-		return V4, nil
+		return IPv4, nil
 	case "V6", "IPV6":
-		return V6, nil
+		return IPv6, nil
 	default:
-		return VX, fmt.Errorf("invalid version name `%s`", name)
+		return IPvx, fmt.Errorf("invalid version name `%s`", name)
 	}
 }