diff --git a/def.go b/def.go
index 756a726..992e15f 100644
--- a/def.go
+++ b/def.go
@@ -1,16 +1,8 @@
 package main
 
-type Packet struct {
-	PLength uint16
-	PType   uint8
-}
-
-type PacketAdminJoin struct {
-	Packet
-	Password   string
-	AppName    string
-	AppVersion string
-}
+import (
+	"bytes"
+)
 
 const (
 	AdminPacketAdminJoin uint8 = 0
@@ -50,3 +42,22 @@ const (
 	AdminPacketServerPong
 	InvalidAdminPacket = 0xFF
 )
+
+type Packet struct {
+	PLength uint16
+	PType   uint8
+}
+
+type PacketAdminJoin struct {
+	Packet
+	Password   string
+	AppName    string
+	AppVersion string
+}
+
+func (p *PacketAdminJoin) Bytes() []byte {
+	buf := new(bytes.Buffer)
+	p.PLength = binary.Size(p)
+	_ = binary.Write(buf, binary.LittleEndian, p)
+	return buf.Bytes()
+}