diff --git a/gold/link/listen.go b/gold/link/listen.go
index 0927277..1290cbb 100644
--- a/gold/link/listen.go
+++ b/gold/link/listen.go
@@ -5,7 +5,6 @@ import (
 	"errors"
 	"io"
 	"net"
-	"reflect"
 	"runtime"
 	"strconv"
 	"sync"
@@ -174,7 +173,7 @@ func (m *Me) dispatch(packet *head.Packet, addr p2p.EndPoint, index int, finish
 		packet.Put()
 		return
 	}
-	if reflect.ValueOf(p.endpoint).IsZero() || !p.endpoint.Euqal(addr) {
+	if helper.IsNilInterface(p.endpoint) || !p.endpoint.Euqal(addr) {
 		if m.ep.Network() == "tcp" && !addr.Euqal(p.endpoint) {
 			logrus.Infoln("[listen] @", index, "set endpoint of peer", p.peerip, "to", addr.String())
 			p.endpoint = addr
diff --git a/gold/link/me.go b/gold/link/me.go
index 5782014..1bf0c82 100644
--- a/gold/link/me.go
+++ b/gold/link/me.go
@@ -5,7 +5,6 @@ import (
 	"encoding/hex"
 	"io"
 	"net"
-	"reflect"
 	"strconv"
 	"sync"
 	"time"
@@ -136,7 +135,7 @@ func NewMe(cfg *MyConfig) (m Me) {
 func (m *Me) Restart() error {
 	oldconn := m.conn
 	m.conn = nil
-	if !reflect.ValueOf(oldconn).IsZero() {
+	if helper.IsNonNilInterface(oldconn) {
 		_ = oldconn.Close()
 	}
 	var err error
@@ -177,7 +176,7 @@ func (m *Me) EndPoint() p2p.EndPoint {
 
 func (m *Me) Close() error {
 	m.connections = nil
-	if !reflect.ValueOf(m.conn).IsZero() {
+	if helper.IsNonNilInterface(m.conn) {
 		_ = m.conn.Close()
 		m.conn = nil
 	}
diff --git a/gold/link/nat.go b/gold/link/nat.go
index e669d18..c661b24 100644
--- a/gold/link/nat.go
+++ b/gold/link/nat.go
@@ -2,7 +2,6 @@ package link
 
 import (
 	"encoding/json"
-	"reflect"
 	"sync/atomic"
 	"time"
 	"unsafe"
@@ -70,7 +69,7 @@ func (l *Link) onNotify(packet []byte) {
 		if err == nil {
 			p, ok := l.me.IsInPeer(peer)
 			if ok {
-				if reflect.ValueOf(p.endpoint).IsZero() || !p.endpoint.Euqal(addr) {
+				if helper.IsNilInterface(p.endpoint) || !p.endpoint.Euqal(addr) {
 					p.endpoint = addr
 					logrus.Infoln("[nat] notify set ep of peer", peer, "to", ep)
 				}
@@ -110,7 +109,7 @@ func (l *Link) onQuery(packet []byte) {
 		lnk, ok := l.me.IsInPeer(p)
 		eps := ""
 		if l.me.ep.Network() == "udp" { // udp has real p2p
-			if reflect.ValueOf(lnk.endpoint).IsZero() {
+			if helper.IsNilInterface(lnk.endpoint) {
 				continue
 			}
 			eps = lnk.endpoint.String()
@@ -121,7 +120,7 @@ func (l *Link) onQuery(packet []byte) {
 		if eps == "" {
 			continue
 		}
-		if ok && !reflect.ValueOf(lnk.endpoint).IsZero() {
+		if ok && helper.IsNonNilInterface(lnk.endpoint) {
 			notify[p] = [2]string{
 				lnk.endpoint.Network(),
 				eps,
diff --git a/gold/link/send.go b/gold/link/send.go
index 8ffac94..0cf183f 100644
--- a/gold/link/send.go
+++ b/gold/link/send.go
@@ -9,7 +9,6 @@ import (
 	"fmt"
 	"io"
 	"math/rand"
-	"reflect"
 
 	"github.com/klauspost/compress/zstd"
 	"github.com/sirupsen/logrus"
@@ -124,7 +123,7 @@ func (l *Link) write(p *head.Packet, teatype uint8, additional uint16, datasz ui
 // write 向 peer 发一个包
 func (l *Link) writeonce(p *head.Packet, teatype uint8, additional uint16, datasz uint32, offset uint16, istransfer, hasmore bool, seq uint32) (int, error) {
 	peerep := l.endpoint
-	if reflect.ValueOf(peerep).IsZero() {
+	if helper.IsNilInterface(peerep) {
 		return 0, errors.New("nil endpoint of " + p.Dst.String())
 	}
 
diff --git a/helper/data.go b/helper/data.go
index 874b10a..6b860cd 100644
--- a/helper/data.go
+++ b/helper/data.go
@@ -1,6 +1,7 @@
 package helper
 
 import (
+	"reflect"
 	"unsafe"
 )
 
@@ -30,3 +31,11 @@ func StringToBytes(s string) (b []byte) {
 	bh.cap = sh.len
 	return b
 }
+
+func IsNilInterface(x any) bool {
+	return x == nil || reflect.ValueOf(x).IsZero()
+}
+
+func IsNonNilInterface(x any) bool {
+	return !IsNilInterface(x)
+}