protocol: add v2 wire protocol with binary framing and capability negotiation (#5294)

2026-04-28 03:49:09 +08:00 · 2026-04-27 00:17:00 +08:00
parent e8dfd6efcc
commit e9464919d1
40 changed files with 1861 additions and 223 deletions
--- a/pkg/config/v1/client.go
+++ b/pkg/config/v1/client.go
@@ -104,6 +104,9 @@ type ClientTransportConfig struct {
 	// Valid values are "tcp", "kcp", "quic", "websocket" and "wss". By default, this value
 	// is "tcp".
 	Protocol string `json:"protocol,omitempty"`
+	// WireProtocol specifies the frpc/frps internal wire protocol version.
+	// Valid values are "v1" and "v2". By default, this value is "v1".
+	WireProtocol string `json:"wireProtocol,omitempty"`
 	// The maximum amount of time a dial to server will wait for a connect to complete.
 	DialServerTimeout int64 `json:"dialServerTimeout,omitempty"`
 	// DialServerKeepAlive specifies the interval between keep-alive probes for an active network connection between frpc and frps.
@@ -143,6 +146,7 @@ type ClientTransportConfig struct {

 func (c *ClientTransportConfig) Complete() {
 	c.Protocol = util.EmptyOr(c.Protocol, "tcp")
+	c.WireProtocol = util.EmptyOr(c.WireProtocol, "v1")
 	c.DialServerTimeout = util.EmptyOr(c.DialServerTimeout, 10)
 	c.DialServerKeepAlive = util.EmptyOr(c.DialServerKeepAlive, 7200)
 	c.ProxyURL = util.EmptyOr(c.ProxyURL, os.Getenv("http_proxy"))
--- a/pkg/config/v1/client_test.go
+++ b/pkg/config/v1/client_test.go
@@ -29,6 +29,7 @@ func TestClientConfigComplete(t *testing.T) {

 	require.EqualValues("token", c.Auth.Method)
 	require.Equal(true, lo.FromPtr(c.Transport.TCPMux))
+	require.Equal("v1", c.Transport.WireProtocol)
 	require.Equal(true, lo.FromPtr(c.LoginFailExit))
 	require.Equal(true, lo.FromPtr(c.Transport.TLS.Enable))
 	require.Equal(true, lo.FromPtr(c.Transport.TLS.DisableCustomTLSFirstByte))
--- a/pkg/config/v1/validation/client.go
+++ b/pkg/config/v1/validation/client.go
@@ -146,6 +146,9 @@ func validateTransportConfig(c *v1.ClientTransportConfig) (Warning, error) {
 	if !slices.Contains(SupportedTransportProtocols, c.Protocol) {
 		errs = AppendError(errs, fmt.Errorf("invalid transport.protocol, optional values are %v", SupportedTransportProtocols))
 	}
+	if !slices.Contains(SupportedWireProtocols, c.WireProtocol) {
+		errs = AppendError(errs, fmt.Errorf("invalid transport.wireProtocol, optional values are %v", SupportedWireProtocols))
+	}
 	return warnings, errs
 }

--- a/pkg/config/v1/validation/validation.go
+++ b/pkg/config/v1/validation/validation.go
@@ -29,6 +29,10 @@ var (
 		"websocket",
 		"wss",
 	}
+	SupportedWireProtocols = []string{
+		"v1",
+		"v2",
+	}

 	SupportedAuthMethods = []v1.AuthMethod{
 		"token",
--- a/pkg/msg/conn_test.go
+++ b/pkg/msg/conn_test.go
@@ -0,0 +1,56 @@
+// Copyright 2026 The frp Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package msg
+
+import (
+	"net"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/fatedier/frp/pkg/proto/wire"
+)
+
+func TestConnReadWriteMsg(t *testing.T) {
+	tests := []struct {
+		name     string
+		protocol string
+	}{
+		{name: "v1", protocol: wire.ProtocolV1},
+		{name: "v2", protocol: wire.ProtocolV2},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			client, server := net.Pipe()
+			defer client.Close()
+			defer server.Close()
+
+			clientConn := NewConn(client, NewReadWriter(client, tt.protocol))
+			serverConn := NewConn(server, NewReadWriter(server, tt.protocol))
+
+			in := &Ping{PrivilegeKey: "key", Timestamp: 123}
+			errCh := make(chan error, 1)
+			go func() {
+				errCh <- clientConn.WriteMsg(in)
+			}()
+
+			out, err := serverConn.ReadMsg()
+			require.NoError(t, err)
+			require.Equal(t, in, out)
+			require.NoError(t, <-errCh)
+		})
+	}
+}
--- a/pkg/msg/handler.go
+++ b/pkg/msg/handler.go
@@ -15,10 +15,90 @@
 package msg

 import (
+	"context"
 	"io"
+	"net"
 	"reflect"
+
+	"github.com/fatedier/frp/pkg/proto/wire"
 )

+type ReadWriter interface {
+	ReadMsg() (Message, error)
+	ReadMsgInto(Message) error
+	WriteMsg(Message) error
+}
+
+type Conn struct {
+	net.Conn
+	rw ReadWriter
+}
+
+func NewConn(conn net.Conn, rw ReadWriter) *Conn {
+	return &Conn{
+		Conn: conn,
+		rw:   rw,
+	}
+}
+
+func (c *Conn) ReadMsg() (Message, error) {
+	return c.rw.ReadMsg()
+}
+
+func (c *Conn) ReadMsgInto(m Message) error {
+	return c.rw.ReadMsgInto(m)
+}
+
+func (c *Conn) WriteMsg(m Message) error {
+	return c.rw.WriteMsg(m)
+}
+
+func (c *Conn) Context() context.Context {
+	if getter, ok := c.Conn.(interface{ Context() context.Context }); ok {
+		return getter.Context()
+	}
+	return context.Background()
+}
+
+func (c *Conn) WithContext(ctx context.Context) {
+	if setter, ok := c.Conn.(interface{ WithContext(context.Context) }); ok {
+		setter.WithContext(ctx)
+	}
+}
+
+type V1ReadWriter struct {
+	rw io.ReadWriter
+}
+
+func NewV1ReadWriter(rw io.ReadWriter) ReadWriter {
+	return &V1ReadWriter{rw: rw}
+}
+
+// NewReadWriter wraps rw with the message codec for the selected wire protocol.
+// An empty protocol keeps the historical v1 behavior for tests and older call sites.
+func NewReadWriter(rw io.ReadWriter, wireProtocol string) ReadWriter {
+	switch wireProtocol {
+	case wire.ProtocolV2:
+		return NewV2ReadWriter(rw)
+	case "", wire.ProtocolV1:
+		return NewV1ReadWriter(rw)
+	default:
+		return NewV1ReadWriter(rw)
+	}
+}
+
+func (rw *V1ReadWriter) ReadMsg() (Message, error) {
+	return ReadMsg(rw.rw)
+}
+
+func (rw *V1ReadWriter) ReadMsgInto(m Message) error {
+	return ReadMsgInto(rw.rw, m)
+}
+
+func (rw *V1ReadWriter) WriteMsg(m Message) error {
+	return WriteMsg(rw.rw, m)
+}
+
 func AsyncHandler(f func(Message)) func(Message) {
 	return func(m Message) {
 		go f(m)
@@ -27,7 +107,7 @@ func AsyncHandler(f func(Message)) func(Message) {

 // Dispatcher is used to send messages to net.Conn or register handlers for messages read from net.Conn.
 type Dispatcher struct {
-	rw io.ReadWriter
+	rw ReadWriter

 	sendCh         chan Message
 	doneCh         chan struct{}
@@ -35,7 +115,7 @@ type Dispatcher struct {
 	defaultHandler func(Message)
 }

-func NewDispatcher(rw io.ReadWriter) *Dispatcher {
+func NewDispatcher(rw ReadWriter) *Dispatcher {
 	return &Dispatcher{
 		rw:          rw,
 		sendCh:      make(chan Message, 100),
@@ -56,14 +136,14 @@ func (d *Dispatcher) sendLoop() {
 		case <-d.doneCh:
 			return
 		case m := <-d.sendCh:
-			_ = WriteMsg(d.rw, m)
+			_ = d.rw.WriteMsg(m)
 		}
 	}
 }

 func (d *Dispatcher) readLoop() {
 	for {
-		m, err := ReadMsg(d.rw)
+		m, err := d.rw.ReadMsg()
 		if err != nil {
 			close(d.doneCh)
 			return
--- a/pkg/msg/msg.go
+++ b/pkg/msg/msg.go
@@ -20,24 +20,24 @@ import (
 )

 const (
-	TypeLogin              = 'o'
-	TypeLoginResp          = '1'
-	TypeNewProxy           = 'p'
-	TypeNewProxyResp       = '2'
-	TypeCloseProxy         = 'c'
-	TypeNewWorkConn        = 'w'
-	TypeReqWorkConn        = 'r'
-	TypeStartWorkConn      = 's'
-	TypeNewVisitorConn     = 'v'
-	TypeNewVisitorConnResp = '3'
-	TypePing               = 'h'
-	TypePong               = '4'
-	TypeUDPPacket          = 'u'
-	TypeNatHoleVisitor     = 'i'
-	TypeNatHoleClient      = 'n'
-	TypeNatHoleResp        = 'm'
-	TypeNatHoleSid         = '5'
-	TypeNatHoleReport      = '6'
+	TypeLogin              byte = 'o'
+	TypeLoginResp          byte = '1'
+	TypeNewProxy           byte = 'p'
+	TypeNewProxyResp       byte = '2'
+	TypeCloseProxy         byte = 'c'
+	TypeNewWorkConn        byte = 'w'
+	TypeReqWorkConn        byte = 'r'
+	TypeStartWorkConn      byte = 's'
+	TypeNewVisitorConn     byte = 'v'
+	TypeNewVisitorConnResp byte = '3'
+	TypePing               byte = 'h'
+	TypePong               byte = '4'
+	TypeUDPPacket          byte = 'u'
+	TypeNatHoleVisitor     byte = 'i'
+	TypeNatHoleClient      byte = 'n'
+	TypeNatHoleResp        byte = 'm'
+	TypeNatHoleSid         byte = '5'
+	TypeNatHoleReport      byte = '6'
 )

 var msgTypeMap = map[byte]any{
--- a/pkg/msg/msg_test.go
+++ b/pkg/msg/msg_test.go
@@ -0,0 +1,55 @@
+// Copyright 2026 The frp Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package msg
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestV1MessageTypeIDsAreStable(t *testing.T) {
+	require.Equal(t, byte('o'), TypeLogin)
+	require.Equal(t, byte('1'), TypeLoginResp)
+	require.Equal(t, byte('p'), TypeNewProxy)
+	require.Equal(t, byte('2'), TypeNewProxyResp)
+	require.Equal(t, byte('c'), TypeCloseProxy)
+	require.Equal(t, byte('w'), TypeNewWorkConn)
+	require.Equal(t, byte('r'), TypeReqWorkConn)
+	require.Equal(t, byte('s'), TypeStartWorkConn)
+	require.Equal(t, byte('v'), TypeNewVisitorConn)
+	require.Equal(t, byte('3'), TypeNewVisitorConnResp)
+	require.Equal(t, byte('h'), TypePing)
+	require.Equal(t, byte('4'), TypePong)
+	require.Equal(t, byte('u'), TypeUDPPacket)
+	require.Equal(t, byte('i'), TypeNatHoleVisitor)
+	require.Equal(t, byte('n'), TypeNatHoleClient)
+	require.Equal(t, byte('m'), TypeNatHoleResp)
+	require.Equal(t, byte('5'), TypeNatHoleSid)
+	require.Equal(t, byte('6'), TypeNatHoleReport)
+}
+
+func TestMessageTypeMapIsCompleteAndUnique(t *testing.T) {
+	require.Len(t, msgTypeMap, 18)
+
+	msgTypes := make(map[reflect.Type]struct{}, len(msgTypeMap))
+
+	for _, m := range msgTypeMap {
+		msgType := reflect.TypeOf(m)
+		require.NotContains(t, msgTypes, msgType)
+		msgTypes[msgType] = struct{}{}
+	}
+}
--- a/pkg/msg/wire_v2.go
+++ b/pkg/msg/wire_v2.go
@@ -0,0 +1,192 @@
+// Copyright 2026 The frp Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package msg
+
+import (
+	"encoding/binary"
+	"encoding/json"
+	"fmt"
+	"io"
+	"reflect"
+
+	"github.com/fatedier/frp/pkg/proto/wire"
+)
+
+const (
+	V2TypeLogin              uint16 = 1
+	V2TypeLoginResp          uint16 = 2
+	V2TypeNewProxy           uint16 = 3
+	V2TypeNewProxyResp       uint16 = 4
+	V2TypeCloseProxy         uint16 = 5
+	V2TypeNewWorkConn        uint16 = 6
+	V2TypeReqWorkConn        uint16 = 7
+	V2TypeStartWorkConn      uint16 = 8
+	V2TypeNewVisitorConn     uint16 = 9
+	V2TypeNewVisitorConnResp uint16 = 10
+	V2TypePing               uint16 = 11
+	V2TypePong               uint16 = 12
+	V2TypeUDPPacket          uint16 = 13
+	V2TypeNatHoleVisitor     uint16 = 14
+	V2TypeNatHoleClient      uint16 = 15
+	V2TypeNatHoleResp        uint16 = 16
+	V2TypeNatHoleSid         uint16 = 17
+	V2TypeNatHoleReport      uint16 = 18
+)
+
+var v2MsgTypeMap = map[uint16]any{
+	V2TypeLogin:              Login{},
+	V2TypeLoginResp:          LoginResp{},
+	V2TypeNewProxy:           NewProxy{},
+	V2TypeNewProxyResp:       NewProxyResp{},
+	V2TypeCloseProxy:         CloseProxy{},
+	V2TypeNewWorkConn:        NewWorkConn{},
+	V2TypeReqWorkConn:        ReqWorkConn{},
+	V2TypeStartWorkConn:      StartWorkConn{},
+	V2TypeNewVisitorConn:     NewVisitorConn{},
+	V2TypeNewVisitorConnResp: NewVisitorConnResp{},
+	V2TypePing:               Ping{},
+	V2TypePong:               Pong{},
+	V2TypeUDPPacket:          UDPPacket{},
+	V2TypeNatHoleVisitor:     NatHoleVisitor{},
+	V2TypeNatHoleClient:      NatHoleClient{},
+	V2TypeNatHoleResp:        NatHoleResp{},
+	V2TypeNatHoleSid:         NatHoleSid{},
+	V2TypeNatHoleReport:      NatHoleReport{},
+}
+
+var v2MsgReflectTypeMap, v2MsgTypeIDMap = buildV2MsgTypeMaps()
+
+func buildV2MsgTypeMaps() (map[uint16]reflect.Type, map[reflect.Type]uint16) {
+	reflectTypeMap := make(map[uint16]reflect.Type, len(v2MsgTypeMap))
+	typeIDMap := make(map[reflect.Type]uint16, len(v2MsgTypeMap))
+	for typeID, m := range v2MsgTypeMap {
+		t := reflect.TypeOf(m)
+		reflectTypeMap[typeID] = t
+		typeIDMap[t] = typeID
+	}
+	return reflectTypeMap, typeIDMap
+}
+
+type V2ReadWriter struct {
+	conn *wire.Conn
+}
+
+func NewV2ReadWriter(rw io.ReadWriter) *V2ReadWriter {
+	return NewV2ReadWriterWithConn(wire.NewConn(rw))
+}
+
+func NewV2ReadWriterWithConn(conn *wire.Conn) *V2ReadWriter {
+	return &V2ReadWriter{conn: conn}
+}
+
+func (rw *V2ReadWriter) WireConn() *wire.Conn {
+	return rw.conn
+}
+
+func (rw *V2ReadWriter) ReadMsg() (Message, error) {
+	f, err := rw.conn.ReadFrame()
+	if err != nil {
+		return nil, err
+	}
+	return DecodeV2MessageFrame(f)
+}
+
+func (rw *V2ReadWriter) ReadMsgInto(m Message) error {
+	f, err := rw.conn.ReadFrame()
+	if err != nil {
+		return err
+	}
+	return DecodeV2MessageFrameInto(f, m)
+}
+
+func (rw *V2ReadWriter) WriteMsg(m Message) error {
+	f, err := EncodeV2MessageFrame(m)
+	if err != nil {
+		return err
+	}
+	return rw.conn.WriteFrame(f)
+}
+
+func DecodeV2MessageFrame(f *wire.Frame) (Message, error) {
+	if f.Type != wire.FrameTypeMessage {
+		return nil, fmt.Errorf("unexpected frame type %d, want %d", f.Type, wire.FrameTypeMessage)
+	}
+	if len(f.Payload) < 2 {
+		return nil, fmt.Errorf("message frame payload too short")
+	}
+	typeID := binary.BigEndian.Uint16(f.Payload[:2])
+	t, ok := v2MsgReflectTypeMap[typeID]
+	if !ok {
+		return nil, fmt.Errorf("unknown v2 message type %d", typeID)
+	}
+	m := reflect.New(t).Interface()
+	if err := json.Unmarshal(f.Payload[2:], m); err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+func DecodeV2MessageFrameInto(f *wire.Frame, out Message) error {
+	if f.Type != wire.FrameTypeMessage {
+		return fmt.Errorf("unexpected frame type %d, want %d", f.Type, wire.FrameTypeMessage)
+	}
+	if len(f.Payload) < 2 {
+		return fmt.Errorf("message frame payload too short")
+	}
+
+	typeID := binary.BigEndian.Uint16(f.Payload[:2])
+	outType := reflect.TypeOf(out)
+	if outType == nil || outType.Kind() != reflect.Pointer {
+		return fmt.Errorf("message target must be a pointer")
+	}
+	elemType := outType.Elem()
+	expectedTypeID, ok := v2MsgTypeIDMap[elemType]
+	if !ok {
+		return fmt.Errorf("unknown v2 message type %s", elemType.String())
+	}
+	if typeID != expectedTypeID {
+		actualType, ok := v2MsgReflectTypeMap[typeID]
+		if !ok {
+			return fmt.Errorf("unknown v2 message type %d", typeID)
+		}
+		return fmt.Errorf("unexpected message type %s, want %s", actualType.String(), elemType.String())
+	}
+	return json.Unmarshal(f.Payload[2:], out)
+}
+
+func EncodeV2MessageFrame(m Message) (*wire.Frame, error) {
+	t := reflect.TypeOf(m)
+	if t == nil {
+		return nil, fmt.Errorf("nil message")
+	}
+	if t.Kind() == reflect.Pointer {
+		t = t.Elem()
+	}
+	typeID, ok := v2MsgTypeIDMap[t]
+	if !ok {
+		return nil, fmt.Errorf("unknown v2 message type %s", t.String())
+	}
+	content, err := json.Marshal(m)
+	if err != nil {
+		return nil, err
+	}
+	payload := make([]byte, 2+len(content))
+	binary.BigEndian.PutUint16(payload[:2], typeID)
+	copy(payload[2:], content)
+	return &wire.Frame{
+		Type:    wire.FrameTypeMessage,
+		Payload: payload,
+	}, nil
+}
--- a/pkg/msg/wire_v2_test.go
+++ b/pkg/msg/wire_v2_test.go
@@ -0,0 +1,121 @@
+// Copyright 2026 The frp Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package msg
+
+import (
+	"bytes"
+	"encoding/binary"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/fatedier/frp/pkg/proto/wire"
+)
+
+func TestV2ReadWriterRoundTrip(t *testing.T) {
+	var buf bytes.Buffer
+	rw := NewV2ReadWriter(&buf)
+
+	in := &Login{
+		Version: "test-version",
+		RunID:   "run-id",
+		User:    "user",
+	}
+	require.NoError(t, rw.WriteMsg(in))
+
+	out, err := rw.ReadMsg()
+	require.NoError(t, err)
+	require.Equal(t, in, out)
+}
+
+func TestNewReadWriter(t *testing.T) {
+	require.IsType(t, &V1ReadWriter{}, NewReadWriter(&bytes.Buffer{}, ""))
+	require.IsType(t, &V1ReadWriter{}, NewReadWriter(&bytes.Buffer{}, wire.ProtocolV1))
+	require.IsType(t, &V2ReadWriter{}, NewReadWriter(&bytes.Buffer{}, wire.ProtocolV2))
+}
+
+func TestV2MessageTypeIDsAreStable(t *testing.T) {
+	require.Equal(t, uint16(1), V2TypeLogin)
+	require.Equal(t, uint16(2), V2TypeLoginResp)
+	require.Equal(t, uint16(3), V2TypeNewProxy)
+	require.Equal(t, uint16(4), V2TypeNewProxyResp)
+	require.Equal(t, uint16(5), V2TypeCloseProxy)
+	require.Equal(t, uint16(6), V2TypeNewWorkConn)
+	require.Equal(t, uint16(7), V2TypeReqWorkConn)
+	require.Equal(t, uint16(8), V2TypeStartWorkConn)
+	require.Equal(t, uint16(9), V2TypeNewVisitorConn)
+	require.Equal(t, uint16(10), V2TypeNewVisitorConnResp)
+	require.Equal(t, uint16(11), V2TypePing)
+	require.Equal(t, uint16(12), V2TypePong)
+	require.Equal(t, uint16(13), V2TypeUDPPacket)
+	require.Equal(t, uint16(14), V2TypeNatHoleVisitor)
+	require.Equal(t, uint16(15), V2TypeNatHoleClient)
+	require.Equal(t, uint16(16), V2TypeNatHoleResp)
+	require.Equal(t, uint16(17), V2TypeNatHoleSid)
+	require.Equal(t, uint16(18), V2TypeNatHoleReport)
+}
+
+func TestV2MessageFrameEncoding(t *testing.T) {
+	frame, err := EncodeV2MessageFrame(&ReqWorkConn{})
+	require.NoError(t, err)
+	require.Equal(t, wire.FrameTypeMessage, frame.Type)
+	require.Len(t, frame.Payload, 4)
+	require.Equal(t, V2TypeReqWorkConn, binary.BigEndian.Uint16(frame.Payload[:2]))
+
+	out, err := DecodeV2MessageFrame(frame)
+	require.NoError(t, err)
+	require.IsType(t, &ReqWorkConn{}, out)
+}
+
+func TestDecodeV2MessageFrameInto(t *testing.T) {
+	in := &StartWorkConn{ProxyName: "tcp", SrcAddr: "127.0.0.1", SrcPort: 1234}
+	frame, err := EncodeV2MessageFrame(in)
+	require.NoError(t, err)
+
+	var out StartWorkConn
+	require.NoError(t, DecodeV2MessageFrameInto(frame, &out))
+	require.Equal(t, *in, out)
+}
+
+func TestDecodeV2MessageFrameRejectsInvalidFrame(t *testing.T) {
+	_, err := DecodeV2MessageFrame(&wire.Frame{Type: wire.FrameTypeClientHello})
+	require.ErrorContains(t, err, "unexpected frame type")
+
+	_, err = DecodeV2MessageFrame(&wire.Frame{Type: wire.FrameTypeMessage, Payload: []byte{0}})
+	require.ErrorContains(t, err, "payload too short")
+
+	payload := make([]byte, 4)
+	binary.BigEndian.PutUint16(payload[:2], 65535)
+	copy(payload[2:], []byte("{}"))
+	_, err = DecodeV2MessageFrame(&wire.Frame{Type: wire.FrameTypeMessage, Payload: payload})
+	require.ErrorContains(t, err, "unknown v2 message type")
+}
+
+func TestDecodeV2MessageFrameIntoRejectsWrongTarget(t *testing.T) {
+	frame, err := EncodeV2MessageFrame(&ReqWorkConn{})
+	require.NoError(t, err)
+
+	var out StartWorkConn
+	err = DecodeV2MessageFrameInto(frame, &out)
+	require.ErrorContains(t, err, "unexpected message type")
+
+	err = DecodeV2MessageFrameInto(frame, StartWorkConn{})
+	require.ErrorContains(t, err, "must be a pointer")
+}
+
+func TestEncodeV2MessageFrameRejectsUnknownMessage(t *testing.T) {
+	_, err := EncodeV2MessageFrame(struct{}{})
+	require.ErrorContains(t, err, "unknown v2 message type")
+}
--- a/pkg/proto/wire/wire.go
+++ b/pkg/proto/wire/wire.go
@@ -0,0 +1,222 @@
+// Copyright 2026 The frp Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package wire
+
+import (
+	"encoding/binary"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net"
+	"slices"
+
+	libnet "github.com/fatedier/golib/net"
+)
+
+const (
+	ProtocolV1 = "v1"
+	ProtocolV2 = "v2"
+
+	WireVersionV2 = 2
+
+	FrameTypeClientHello uint16 = 1
+	FrameTypeServerHello uint16 = 2
+	FrameTypeMessage     uint16 = 16
+
+	MessageCodecJSON           = "json"
+	DefaultMaxFramePayloadSize = 64 * 1024
+
+	MagicV2 = "FRP\x00\x02\r\n"
+)
+
+type Frame struct {
+	Type    uint16
+	Flags   uint16
+	Payload []byte
+}
+
+type Conn struct {
+	rw                  io.ReadWriter
+	maxFramePayloadSize uint32
+}
+
+func NewConn(rw io.ReadWriter) *Conn {
+	return &Conn{
+		rw:                  rw,
+		maxFramePayloadSize: DefaultMaxFramePayloadSize,
+	}
+}
+
+func (c *Conn) ReadFrame() (*Frame, error) {
+	header := make([]byte, 8)
+	if _, err := io.ReadFull(c.rw, header); err != nil {
+		return nil, err
+	}
+
+	frameType := binary.BigEndian.Uint16(header[0:2])
+	flags := binary.BigEndian.Uint16(header[2:4])
+	length := binary.BigEndian.Uint32(header[4:8])
+	if flags != 0 {
+		return nil, fmt.Errorf("unsupported frame flags: %d", flags)
+	}
+	if length > c.maxFramePayloadSize {
+		return nil, fmt.Errorf("frame payload length %d exceeds limit %d", length, c.maxFramePayloadSize)
+	}
+
+	payload := make([]byte, length)
+	if _, err := io.ReadFull(c.rw, payload); err != nil {
+		return nil, err
+	}
+	return &Frame{
+		Type:    frameType,
+		Flags:   flags,
+		Payload: payload,
+	}, nil
+}
+
+func (c *Conn) WriteFrame(f *Frame) error {
+	if f.Flags != 0 {
+		return fmt.Errorf("unsupported frame flags: %d", f.Flags)
+	}
+	if len(f.Payload) > int(c.maxFramePayloadSize) {
+		return fmt.Errorf("frame payload length %d exceeds limit %d", len(f.Payload), c.maxFramePayloadSize)
+	}
+
+	header := make([]byte, 8)
+	binary.BigEndian.PutUint16(header[0:2], f.Type)
+	binary.BigEndian.PutUint16(header[2:4], f.Flags)
+	binary.BigEndian.PutUint32(header[4:8], uint32(len(f.Payload)))
+	if _, err := c.rw.Write(header); err != nil {
+		return err
+	}
+	_, err := c.rw.Write(f.Payload)
+	return err
+}
+
+func (c *Conn) ReadJSONFrame(frameType uint16, out any) error {
+	f, err := c.ReadFrame()
+	if err != nil {
+		return err
+	}
+	if f.Type != frameType {
+		return fmt.Errorf("unexpected frame type %d, want %d", f.Type, frameType)
+	}
+	return c.UnmarshalFrame(f, out)
+}
+
+func (c *Conn) UnmarshalFrame(f *Frame, out any) error {
+	return json.Unmarshal(f.Payload, out)
+}
+
+func (c *Conn) WriteJSONFrame(frameType uint16, in any) error {
+	payload, err := json.Marshal(in)
+	if err != nil {
+		return err
+	}
+	return c.WriteFrame(&Frame{
+		Type:    frameType,
+		Payload: payload,
+	})
+}
+
+func WriteMagic(w io.Writer) error {
+	_, err := io.WriteString(w, MagicV2)
+	return err
+}
+
+func WriteMagicIfV2(w io.Writer, wireProtocol string) error {
+	if wireProtocol != ProtocolV2 {
+		return nil
+	}
+	return WriteMagic(w)
+}
+
+func CheckMagic(conn net.Conn) (out net.Conn, isV2 bool, err error) {
+	sharedConn, r := libnet.NewSharedConnSize(conn, len(MagicV2))
+	buf := make([]byte, len(MagicV2))
+	if _, err = io.ReadFull(r, buf); err != nil {
+		return nil, false, err
+	}
+	for i := range MagicV2 {
+		if buf[i] != MagicV2[i] {
+			return sharedConn, false, nil
+		}
+	}
+	return conn, true, nil
+}
+
+type BootstrapInfo struct {
+	Transport string `json:"transport,omitempty"`
+	TLS       bool   `json:"tls,omitempty"`
+	TCPMux    bool   `json:"tcpMux,omitempty"`
+}
+
+type ClientHello struct {
+	Bootstrap    BootstrapInfo      `json:"bootstrap,omitempty"`
+	Capabilities ClientCapabilities `json:"capabilities,omitempty"`
+}
+
+type ClientCapabilities struct {
+	Message MessageCapabilities `json:"message,omitempty"`
+}
+
+type MessageCapabilities struct {
+	Codecs []string `json:"codecs,omitempty"`
+}
+
+type ServerHello struct {
+	Selected ServerSelection `json:"selected,omitempty"`
+	Error    string          `json:"error,omitempty"`
+}
+
+type ServerSelection struct {
+	Message MessageSelection `json:"message,omitempty"`
+}
+
+type MessageSelection struct {
+	Codec string `json:"codec,omitempty"`
+}
+
+func DefaultClientHello(bootstrap BootstrapInfo) ClientHello {
+	return ClientHello{
+		Bootstrap: bootstrap,
+		Capabilities: ClientCapabilities{
+			Message: MessageCapabilities{
+				Codecs: []string{MessageCodecJSON},
+			},
+		},
+	}
+}
+
+func DefaultServerHello() ServerHello {
+	return ServerHello{
+		Selected: ServerSelection{
+			Message: MessageSelection{
+				Codec: MessageCodecJSON,
+			},
+		},
+	}
+}
+
+func Supports(list []string, value string) bool {
+	return slices.Contains(list, value)
+}
+
+func ValidateClientHello(h ClientHello) error {
+	if !Supports(h.Capabilities.Message.Codecs, MessageCodecJSON) {
+		return fmt.Errorf("unsupported message codec")
+	}
+	return nil
+}
--- a/pkg/proto/wire/wire_test.go
+++ b/pkg/proto/wire/wire_test.go
@@ -0,0 +1,120 @@
+// Copyright 2026 The frp Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package wire
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+	"net"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestFrameRoundTrip(t *testing.T) {
+	var buf bytes.Buffer
+	conn := NewConn(&buf)
+
+	in := DefaultClientHello(BootstrapInfo{
+		Transport: "tcp",
+		TLS:       true,
+		TCPMux:    true,
+	})
+	require.NoError(t, conn.WriteJSONFrame(FrameTypeClientHello, in))
+
+	var out ClientHello
+	require.NoError(t, conn.ReadJSONFrame(FrameTypeClientHello, &out))
+	require.Equal(t, in, out)
+}
+
+func TestReadFrameRejectsUnsupportedFlags(t *testing.T) {
+	var buf bytes.Buffer
+	header := make([]byte, 8)
+	binary.BigEndian.PutUint16(header[0:2], FrameTypeMessage)
+	binary.BigEndian.PutUint16(header[2:4], 1)
+	binary.BigEndian.PutUint32(header[4:8], 0)
+	buf.Write(header)
+
+	_, err := NewConn(&buf).ReadFrame()
+	require.ErrorContains(t, err, "unsupported frame flags")
+}
+
+func TestReadFrameRejectsOversizedPayload(t *testing.T) {
+	var buf bytes.Buffer
+	header := make([]byte, 8)
+	binary.BigEndian.PutUint16(header[0:2], FrameTypeMessage)
+	binary.BigEndian.PutUint32(header[4:8], DefaultMaxFramePayloadSize+1)
+	buf.Write(header)
+
+	_, err := NewConn(&buf).ReadFrame()
+	require.ErrorContains(t, err, "exceeds limit")
+}
+
+func TestCheckMagicV2ConsumesMagic(t *testing.T) {
+	client, server := net.Pipe()
+	defer server.Close()
+
+	want := []byte("payload")
+	go func() {
+		defer client.Close()
+		_, _ = client.Write(append([]byte(MagicV2), want...))
+	}()
+
+	out, isV2, err := CheckMagic(server)
+	require.NoError(t, err)
+	require.True(t, isV2)
+
+	got := make([]byte, len(want))
+	_, err = io.ReadFull(out, got)
+	require.NoError(t, err)
+	require.Equal(t, want, got)
+}
+
+func TestWriteMagicIfV2(t *testing.T) {
+	var buf bytes.Buffer
+	require.NoError(t, WriteMagicIfV2(&buf, ProtocolV1))
+	require.Empty(t, buf.Bytes())
+
+	require.NoError(t, WriteMagicIfV2(&buf, ProtocolV2))
+	require.Equal(t, []byte(MagicV2), buf.Bytes())
+}
+
+func TestCheckMagicV1PreservesReadBytes(t *testing.T) {
+	client, server := net.Pipe()
+	defer server.Close()
+
+	want := []byte("legacy payload")
+	go func() {
+		defer client.Close()
+		_, _ = client.Write(want)
+	}()
+
+	out, isV2, err := CheckMagic(server)
+	require.NoError(t, err)
+	require.False(t, isV2)
+
+	got, err := io.ReadAll(out)
+	require.NoError(t, err)
+	require.Equal(t, want, got)
+}
+
+func TestValidateClientHello(t *testing.T) {
+	require.NoError(t, ValidateClientHello(DefaultClientHello(BootstrapInfo{})))
+
+	hello := DefaultClientHello(BootstrapInfo{})
+	hello.Capabilities.Message.Codecs = []string{"unknown"}
+	require.ErrorContains(t, ValidateClientHello(hello), "unsupported message codec")
+}
--- a/pkg/util/net/conn.go
+++ b/pkg/util/net/conn.go
@@ -133,7 +133,7 @@ type CloseNotifyConn struct {
 	net.Conn

 	// 1 means closed
-	closeFlag int32
+	closeFlag atomic.Int32

 	closeFn func(error)
 }
@@ -147,7 +147,7 @@ func WrapCloseNotifyConn(c net.Conn, closeFn func(error)) *CloseNotifyConn {
 }

 func (cc *CloseNotifyConn) Close() (err error) {
-	pflag := atomic.SwapInt32(&cc.closeFlag, 1)
+	pflag := cc.closeFlag.Swap(1)
 	if pflag == 0 {
 		err = cc.Conn.Close()
 		if cc.closeFn != nil {
@@ -159,7 +159,7 @@ func (cc *CloseNotifyConn) Close() (err error) {

 // CloseWithError closes the connection and passes the error to the close callback.
 func (cc *CloseNotifyConn) CloseWithError(err error) error {
-	pflag := atomic.SwapInt32(&cc.closeFlag, 1)
+	pflag := cc.closeFlag.Swap(1)
 	if pflag == 0 {
 		closeErr := cc.Conn.Close()
 		if cc.closeFn != nil {
@@ -173,7 +173,7 @@ func (cc *CloseNotifyConn) CloseWithError(err error) error {
 type StatsConn struct {
 	net.Conn

-	closed     int64 // 1 means closed
+	closed     atomic.Int64 // 1 means closed
 	totalRead  int64
 	totalWrite int64
 	statsFunc  func(totalRead, totalWrite int64)
@@ -199,7 +199,7 @@ func (statsConn *StatsConn) Write(p []byte) (n int, err error) {
 }

 func (statsConn *StatsConn) Close() (err error) {
-	old := atomic.SwapInt64(&statsConn.closed, 1)
+	old := statsConn.closed.Swap(1)
 	if old != 1 {
 		err = statsConn.Conn.Close()
 		if statsConn.statsFunc != nil {