diff --git a/command.go b/command.go
index fb5e75a..33d5ff7 100644
--- a/command.go
+++ b/command.go
@@ -12,6 +12,7 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/zhaojh329/rtty-go/proto"
 	"github.com/zhaojh329/rttys/v5/utils"
 
 	"github.com/gin-gonic/gin"
@@ -74,7 +75,7 @@ func (dev *Device) handleCmdReq(c *gin.Context, info *CommandReqInfo) {
 
 	log.Debug().Msgf("send cmd request for device '%s', token '%s'", dev.id, token)
 
-	err := dev.WriteMsg(msgTypeCmd, "", msg.Bytes())
+	err := dev.WriteMsg(proto.MsgTypeCmd, msg)
 	if err != nil {
 		cmdErrResp(c, rttyCmdErrOffline)
 		return
diff --git a/device.go b/device.go
index 015a826..93c17b9 100644
--- a/device.go
+++ b/device.go
@@ -6,7 +6,6 @@
 package main
 
 import (
-	"bufio"
 	"bytes"
 	"context"
 	"crypto/tls"
@@ -21,12 +20,11 @@ import (
 	"sync"
 	"time"
 
-	"github.com/zhaojh329/rttys/v5/utils"
-
 	"github.com/gorilla/websocket"
 	jsoniter "github.com/json-iterator/go"
 	"github.com/rs/zerolog/log"
-	"github.com/valyala/bytebufferpool"
+	"github.com/zhaojh329/rtty-go/proto"
+	"github.com/zhaojh329/rttys/v5/utils"
 )
 
 type DeviceInfo struct {
@@ -54,48 +52,14 @@ type Device struct {
 	commands sync.Map
 	https    sync.Map
 
-	conn    net.Conn
-	br      *bufio.Reader
-	readBuf []byte
-	close   sync.Once
-	ctx     context.Context
-	cancel  context.CancelFunc
+	conn   net.Conn
+	close  sync.Once
+	ctx    context.Context
+	cancel context.CancelFunc
+
+	msg *proto.MsgReaderWriter
 }
 
-const (
-	msgTypeRegister = byte(iota)
-	msgTypeLogin
-	msgTypeLogout
-	msgTypeTermData
-	msgTypeWinsize
-	msgTypeCmd
-	msgTypeHeartbeat
-	msgTypeFile
-	msgTypeHttp
-	msgTypeAck
-)
-
-const (
-	msgTypeFileSend = byte(iota)
-	msgTypeFileRecv
-	msgTypeFileInfo
-	msgTypeFileData
-	msgTypeFileAck
-	msgTypeFileAbort
-)
-
-const (
-	msgRegAttrHeartbeat = iota
-	msgRegAttrDevid
-	msgRegAttrDescription
-	msgRegAttrToken
-	msgRegAttrGroup
-)
-
-const (
-	msgHeartbeatAttrUptime = iota
-)
-
 const (
 	devRegErrUnsupportedProto = iota + 1
 	devRegErrInvalidToken
@@ -120,13 +84,13 @@ var DevRegErrMsg = map[byte]string{
 }
 
 var DeviceMsgHandlers = map[byte]func(*Device, []byte) error{
-	msgTypeHeartbeat: handleHeartbeatMsg,
-	msgTypeLogin:     handleLoginMsg,
-	msgTypeLogout:    handleLogoutMsg,
-	msgTypeTermData:  handleTermDataMsg,
-	msgTypeFile:      handleFileMsg,
-	msgTypeCmd:       handleCmdMsg,
-	msgTypeHttp:      handleHttpMsg,
+	proto.MsgTypeHeartbeat: handleHeartbeatMsg,
+	proto.MsgTypeLogin:     handleLoginMsg,
+	proto.MsgTypeLogout:    handleLogoutMsg,
+	proto.MsgTypeTermData:  handleTermDataMsg,
+	proto.MsgTypeFile:      handleFileMsg,
+	proto.MsgTypeCmd:       handleCmdMsg,
+	proto.MsgTypeHttp:      handleHttpMsg,
 }
 
 func (srv *RttyServer) ListenDevices() {
@@ -185,7 +149,8 @@ func handleDeviceConnection(srv *RttyServer, conn net.Conn) {
 		conn:      conn,
 		heartbeat: DefaultHeartbeat,
 		timestamp: time.Now().Unix(),
-		br:        bufio.NewReader(conn),
+
+		msg: proto.NewMsgReaderWriter(proto.RoleRttys, conn),
 	}
 	defer dev.Close(srv)
 
@@ -201,7 +166,7 @@ func handleDeviceConnection(srv *RttyServer, conn net.Conn) {
 		return
 	}
 
-	if typ != msgTypeRegister {
+	if typ != proto.MsgTypeRegister {
 		log.Error().Msg("register msg expected first")
 		return
 	}
@@ -214,7 +179,7 @@ func handleDeviceConnection(srv *RttyServer, conn net.Conn) {
 
 	code := dev.Register(srv)
 
-	err = dev.WriteMsg(msgTypeRegister, "", append([]byte{code}, DevRegErrMsg[code]...))
+	err = dev.WriteMsg(proto.MsgTypeRegister, code, DevRegErrMsg[code])
 	if err != nil {
 		log.Error().Err(err).Msgf("send register to device '%s' fail", dev.id)
 		return
@@ -238,11 +203,11 @@ func handleDeviceConnection(srv *RttyServer, conn net.Conn) {
 			return
 		}
 
-		log.Debug().Msgf("device msg %s from device %s", msgTypeName(typ), dev.id)
+		log.Debug().Msgf("device msg %s from device %s", proto.MsgTypeName(typ), dev.id)
 
 		handler, ok := DeviceMsgHandlers[typ]
 		if !ok {
-			log.Error().Msgf("unexpected message '%s' from device '%s'", msgTypeName(typ), dev.id)
+			log.Error().Msgf("unexpected message '%s' from device '%s'", proto.MsgTypeName(typ), dev.id)
 			return
 		}
 
@@ -254,85 +219,12 @@ func handleDeviceConnection(srv *RttyServer, conn net.Conn) {
 	}
 }
 
-func msgTypeName(typ byte) string {
-	switch typ {
-	case msgTypeRegister:
-		return "register"
-	case msgTypeLogin:
-		return "login"
-	case msgTypeLogout:
-		return "logout"
-	case msgTypeTermData:
-		return "termdata"
-	case msgTypeWinsize:
-		return "winsize"
-	case msgTypeCmd:
-		return "cmd"
-	case msgTypeHeartbeat:
-		return "heartbeat"
-	case msgTypeFile:
-		return "file"
-	case msgTypeHttp:
-		return "http"
-	case msgTypeAck:
-		return "ack"
-	default:
-		return fmt.Sprintf("unknown(%d)", typ)
-	}
-}
-
 func (dev *Device) ReadMsg() (byte, []byte, error) {
-	head := make([]byte, 3)
-	br := dev.br
-
-	_, err := io.ReadFull(br, head)
-	if err != nil {
-		return 0, nil, err
-	}
-
-	typ := head[0]
-
-	msgLen := binary.BigEndian.Uint16(head[1:])
-
-	if cap(dev.readBuf) < int(msgLen) {
-		dev.readBuf = make([]byte, msgLen)
-	} else {
-		dev.readBuf = dev.readBuf[:msgLen]
-	}
-
-	_, err = io.ReadFull(br, dev.readBuf)
-	if err != nil {
-		return 0, nil, err
-	}
-
-	return typ, dev.readBuf, nil
+	return dev.msg.Read()
 }
 
-func (dev *Device) WriteMsg(typ byte, sid string, data []byte) error {
-	bb := bytebufferpool.Get()
-	defer bytebufferpool.Put(bb)
-
-	b := []byte{typ, 0, 0}
-
-	binary.BigEndian.PutUint16(b[1:], uint16(len(sid)+len(data)))
-
-	bb.Write(b)
-	bb.WriteString(sid)
-	bb.Write(data)
-
-	_, err := bb.WriteTo(dev.conn)
-
-	return err
-}
-
-func (dev *Device) WriteFileMsg(typ byte, sid string, fileType byte, data []byte) error {
-	bb := bytebufferpool.Get()
-	defer bytebufferpool.Put(bb)
-
-	bb.WriteByte(fileType)
-	bb.Write(data)
-
-	return dev.WriteMsg(typ, sid, bb.Bytes())
+func (dev *Device) WriteMsg(typ byte, data ...any) error {
+	return dev.msg.Write(typ, data...)
 }
 
 func (dev *Device) Close(srv *RttyServer) {
@@ -345,10 +237,6 @@ func (dev *Device) Close(srv *RttyServer) {
 }
 
 func (dev *Device) ParseRegister(b []byte) error {
-	if len(b) < 1 {
-		return fmt.Errorf("too short")
-	}
-
 	dev.proto = b[0]
 
 	if dev.proto > 4 {
@@ -359,15 +247,15 @@ func (dev *Device) ParseRegister(b []byte) error {
 
 		for typ, val := range attrs {
 			switch typ {
-			case msgRegAttrHeartbeat:
+			case proto.MsgRegAttrHeartbeat:
 				dev.heartbeat = time.Duration(val[0]) * time.Second
-			case msgRegAttrDevid:
+			case proto.MsgRegAttrDevid:
 				dev.id = string(val)
-			case msgRegAttrDescription:
+			case proto.MsgRegAttrDescription:
 				dev.desc = string(val)
-			case msgRegAttrToken:
+			case proto.MsgRegAttrToken:
 				dev.token = string(val)
-			case msgRegAttrGroup:
+			case proto.MsgRegAttrGroup:
 				dev.group = string(val)
 			}
 		}
@@ -389,15 +277,15 @@ func (dev *Device) ParseRegister(b []byte) error {
 		return fmt.Errorf("not found device id")
 	}
 
-	if len(dev.id) > 32 {
+	if len(dev.id) > proto.MaximumDevIDLen {
 		return fmt.Errorf("device id too long")
 	}
 
-	if len(dev.desc) > 126 {
+	if len(dev.desc) > proto.MaximumDescLen {
 		return fmt.Errorf("device desc too long")
 	}
 
-	if len(dev.group) > 16 {
+	if len(dev.group) > proto.MaximumGroupLen {
 		return fmt.Errorf("device group too long")
 	}
 
@@ -449,7 +337,7 @@ func handleHeartbeatMsg(dev *Device, data []byte) error {
 	if !parseHeartbeat(dev, data) {
 		return fmt.Errorf("invalid heartbeat msg from device '%s'", dev.id)
 	}
-	return dev.WriteMsg(msgTypeHeartbeat, "", nil)
+	return dev.WriteMsg(proto.MsgTypeHeartbeat)
 }
 
 func parseHeartbeat(dev *Device, data []byte) bool {
@@ -461,7 +349,7 @@ func parseHeartbeat(dev *Device, data []byte) bool {
 
 		for typ, val := range attrs {
 			switch typ {
-			case msgHeartbeatAttrUptime:
+			case proto.MsgHeartbeatAttrUptime:
 				dev.uptime = binary.BigEndian.Uint32(val)
 			}
 		}
@@ -476,10 +364,6 @@ func parseHeartbeat(dev *Device, data []byte) bool {
 }
 
 func handleLogoutMsg(dev *Device, data []byte) error {
-	if len(data) < 32 {
-		return fmt.Errorf("invalid logout msg from device '%s'", dev.id)
-	}
-
 	sid := string(data[:32])
 
 	if val, loaded := dev.users.LoadAndDelete(sid); loaded {
@@ -491,10 +375,6 @@ func handleLogoutMsg(dev *Device, data []byte) error {
 }
 
 func handleLoginMsg(dev *Device, data []byte) error {
-	if len(data) < 33 {
-		return fmt.Errorf("invalid login msg from device '%s'", dev.id)
-	}
-
 	sid := string(data[:32])
 	code := data[32]
 
@@ -525,10 +405,6 @@ func handleLoginMsg(dev *Device, data []byte) error {
 }
 
 func handleTermDataMsg(dev *Device, data []byte) error {
-	if len(data) < 32 {
-		return fmt.Errorf("invalid term data msg from device '%s'", dev.id)
-	}
-
 	sid := string(data[:32])
 
 	if val, ok := dev.users.Load(sid); ok {
@@ -541,10 +417,6 @@ func handleTermDataMsg(dev *Device, data []byte) error {
 }
 
 func handleFileMsg(dev *Device, data []byte) error {
-	if len(data) < 33 {
-		return fmt.Errorf("invalid file msg from device '%s'", dev.id)
-	}
-
 	sid := string(data[:32])
 	typ := data[32]
 
@@ -552,21 +424,21 @@ func handleFileMsg(dev *Device, data []byte) error {
 		user := val.(*User)
 
 		switch typ {
-		case msgTypeFileSend:
+		case proto.MsgTypeFileSend:
 			user.WriteMsg(websocket.TextMessage,
 				fmt.Appendf(nil, `{"type":"sendfile", "name": "%s"}`, string(data[33:])))
 
-		case msgTypeFileRecv:
+		case proto.MsgTypeFileRecv:
 			user.WriteMsg(websocket.TextMessage, []byte(`{"type":"recvfile"}`))
 
-		case msgTypeFileData:
+		case proto.MsgTypeFileData:
 			data[32] = 1
 			user.WriteMsg(websocket.BinaryMessage, data[32:])
 
-		case msgTypeFileAck:
+		case proto.MsgTypeFileAck:
 			user.WriteMsg(websocket.TextMessage, []byte(`{"type":"fileAck"}`))
 
-		case msgTypeFileAbort:
+		case proto.MsgTypeFileAbort:
 			user.WriteMsg(websocket.BinaryMessage, []byte{1})
 		}
 	}
@@ -575,10 +447,6 @@ func handleFileMsg(dev *Device, data []byte) error {
 }
 
 func handleHttpMsg(dev *Device, data []byte) error {
-	if len(data) < 18 {
-		return fmt.Errorf("invalid http msg from device '%s'", dev.id)
-	}
-
 	addr := data[:18]
 	data = data[18:]
 
diff --git a/go.mod b/go.mod
index e1154fc..2c2d533 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,8 @@
 module github.com/zhaojh329/rttys/v5
 
-go 1.24
+go 1.24.4
+
+toolchain go1.24.5
 
 require (
 	github.com/dwdcth/consoleEx v0.0.0-20180521133551-f56f6eb78b76
@@ -15,6 +17,7 @@ require (
 	github.com/rs/zerolog v1.34.0
 	github.com/urfave/cli/v3 v3.3.8
 	github.com/valyala/bytebufferpool v1.0.0
+	github.com/zhaojh329/rtty-go v1.1.0
 )
 
 require (
@@ -39,7 +42,7 @@ require (
 	golang.org/x/arch v0.18.0 // indirect
 	golang.org/x/crypto v0.39.0 // indirect
 	golang.org/x/net v0.41.0 // indirect
-	golang.org/x/sys v0.33.0 // indirect
+	golang.org/x/sys v0.34.0 // indirect
 	golang.org/x/text v0.26.0 // indirect
 	google.golang.org/protobuf v1.36.6 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
diff --git a/go.sum b/go.sum
index 2b7194e..775ee51 100644
--- a/go.sum
+++ b/go.sum
@@ -95,6 +95,8 @@ github.com/urfave/cli/v3 v3.3.8 h1:BzolUExliMdet9NlJ/u4m5vHSotJ3PzEqSAZ1oPMa/E=
 github.com/urfave/cli/v3 v3.3.8/go.mod h1:FJSKtM/9AiiTOJL4fJ6TbMUkxBXn7GO9guZqoZtpYpo=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
 github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
+github.com/zhaojh329/rtty-go v1.1.0 h1:aZHI2prDFKSkn+8i5YxmS+ixpYGMgRlzqUZcxc7mlLQ=
+github.com/zhaojh329/rtty-go v1.1.0/go.mod h1:U5f1woopWzirdSKpc6kI7NTFtAP8k8XU4mUQ0olm+i8=
 golang.org/x/arch v0.18.0 h1:WN9poc33zL4AzGxqf8VtpKUnGvMi8O9lhNyBMF/85qc=
 golang.org/x/arch v0.18.0/go.mod h1:bdwinDaKcfZUGpH09BB7ZmOfhalA8lQdzl62l8gGWsk=
 golang.org/x/crypto v0.39.0 h1:SHs+kF4LP+f+p14esP5jAoDpHU8Gu/v9lFRK6IT5imM=
@@ -104,8 +106,8 @@ golang.org/x/net v0.41.0/go.mod h1:B/K4NNqkfmg07DQYrbwvSluqCJOOXwUjeb/5lOisjbA=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw=
-golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
+golang.org/x/sys v0.34.0 h1:H5Y5sJ2L2JRdyv7ROF1he/lPdvFsd0mJHFw2ThKHxLA=
+golang.org/x/sys v0.34.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
 golang.org/x/text v0.26.0 h1:P42AVeLghgTYr4+xUnTRKDMqpar+PtX7KWuNQL21L8M=
 golang.org/x/text v0.26.0/go.mod h1:QK15LZJUUQVJxhz7wXgxSy/CJaTFjd0G+YLonydOVQA=
 google.golang.org/protobuf v1.36.6 h1:z1NpPI8ku2WgiWnf+t9wTPsn6eP1L7ksHUlkfLvd9xY=
diff --git a/http.go b/http.go
index 47ae259..0ed3634 100644
--- a/http.go
+++ b/http.go
@@ -19,6 +19,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/zhaojh329/rtty-go/proto"
 	"github.com/zhaojh329/rttys/v5/utils"
 
 	"github.com/gin-gonic/gin"
@@ -305,7 +306,7 @@ func sendHttpReq(dev *Device, https bool, srcAddr []byte, destAddr []byte, data
 	bb.Write(destAddr)
 	bb.Write(data)
 
-	dev.WriteMsg(msgTypeHttp, "", bb.Bytes())
+	dev.WriteMsg(proto.MsgTypeHttp, bb)
 }
 
 func genDestAddr(addr string) []byte {
diff --git a/user.go b/user.go
index b28ee88..0603603 100644
--- a/user.go
+++ b/user.go
@@ -7,12 +7,12 @@ package main
 
 import (
 	"context"
-	"encoding/binary"
 	"net/http"
 	"sync"
 	"sync/atomic"
 	"time"
 
+	"github.com/zhaojh329/rtty-go/proto"
 	"github.com/zhaojh329/rttys/v5/utils"
 
 	"github.com/gin-gonic/gin"
@@ -84,7 +84,7 @@ func handleUserConnection(srv *RttyServer, c *gin.Context) {
 
 	defer user.Close()
 
-	if err := dev.WriteMsg(msgTypeLogin, sid, nil); err != nil {
+	if err := dev.WriteMsg(proto.MsgTypeLogin, sid); err != nil {
 		log.Error().Msgf("send login msg to device %s fail: %v", dev.id, err)
 		return
 	}
@@ -117,7 +117,7 @@ func (user *User) Close() {
 		user.closed.Store(true)
 
 		if _, loaded := dev.users.LoadAndDelete(sid); loaded {
-			dev.WriteMsg(msgTypeLogout, sid, nil)
+			dev.WriteMsg(proto.MsgTypeLogout, sid)
 		}
 
 		dev.pending.Delete(sid)
@@ -172,9 +172,9 @@ func (user *User) handleMsg() {
 				return
 			}
 
-			typ := msgTypeTermData
+			typ := proto.MsgTypeTermData
 			if data[0] == 1 {
-				typ = msgTypeFile
+				typ = proto.MsgTypeFile
 			}
 
 			err = dev.WriteMsg(typ, sid, data[1:])
@@ -189,30 +189,19 @@ func (user *User) handleMsg() {
 
 			switch msg.Type {
 			case "winsize":
-				b := make([]byte, 4)
-
-				binary.BigEndian.PutUint16(b, msg.Cols)
-				binary.BigEndian.PutUint16(b[2:], msg.Rows)
-
-				err = dev.WriteMsg(msgTypeWinsize, sid, b)
+				err = dev.WriteMsg(proto.MsgTypeWinsize, sid, msg.Cols, msg.Rows)
 
 			case "ack":
-				b := make([]byte, 2)
-				binary.BigEndian.PutUint16(b, msg.Ack)
-				err = dev.WriteMsg(msgTypeAck, sid, b)
+				err = dev.WriteMsg(proto.MsgTypeAck, sid, msg.Ack)
 
 			case "fileInfo":
-				b := make([]byte, 4+len(msg.Name))
-				binary.BigEndian.PutUint32(b, msg.Size)
-				copy(b[4:], []byte(msg.Name))
-
-				err = dev.WriteFileMsg(msgTypeFile, sid, msgTypeFileInfo, b)
+				err = dev.WriteMsg(proto.MsgTypeFile, sid, proto.MsgTypeFileInfo, msg.Size, msg.Name)
 
 			case "fileCanceled":
-				err = dev.WriteFileMsg(msgTypeFile, sid, msgTypeFileAbort, nil)
+				err = dev.WriteMsg(proto.MsgTypeFile, sid, proto.MsgTypeFileAbort)
 
 			case "fileAck":
-				err = dev.WriteFileMsg(msgTypeFile, sid, msgTypeFileAck, nil)
+				err = dev.WriteMsg(proto.MsgTypeFile, sid, proto.MsgTypeFileAck)
 			}
 		}