Feature(proxy): support gost relay protocol (#310)

engine/parse.go

@@ -7,6 +7,8 @@ import (
 	"net/url"
 	"strings"
 
+	"github.com/gorilla/schema"
+
 	"github.com/xjasonlyu/tun2socks/v2/core/device"
 	"github.com/xjasonlyu/tun2socks/v2/core/device/fdbased"
 	"github.com/xjasonlyu/tun2socks/v2/core/device/tun"
@@ -92,6 +94,8 @@ func parseProxy(s string) (proxy.Proxy, error) {
 		return parseSocks5(u)
 	case proto.Shadowsocks.String():
 		return parseShadowsocks(u)
+	case proto.Relay.String():
+		return parseRelay(u)
 	default:
 		return nil, fmt.Errorf("unsupported protocol: %s", protocol)
 	}
@@ -158,6 +162,20 @@ func parseShadowsocks(u *url.URL) (proxy.Proxy, error) {
 	return proxy.NewShadowsocks(address, method, password, obfsMode, obfsHost)
 }
 
+func parseRelay(u *url.URL) (proxy.Proxy, error) {
+	address, username := u.Host, u.User.Username()
+	password, _ := u.User.Password()
+
+	opts := struct {
+		NoDelay bool
+	}{}
+	if err := schema.NewDecoder().Decode(&opts, u.Query()); err != nil {
+		return nil, err
+	}
+
+	return proxy.NewRelay(address, username, password, opts.NoDelay)
+}
+
 func parseMulticastGroups(s string) (multicastGroups []net.IP, _ error) {
 	ipStrings := strings.Split(s, ",")
 	for _, ipString := range ipStrings {

go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/go-chi/chi/v5 v5.0.10
 	github.com/go-chi/cors v1.2.1
 	github.com/go-chi/render v1.0.3
+	github.com/go-gost/relay v0.4.1-0.20230916134211-828f314ddfe7
 	github.com/google/uuid v1.3.1
 	github.com/gorilla/schema v1.2.0
 	github.com/gorilla/websocket v1.5.0

go.sum

@@ -12,6 +12,8 @@ github.com/go-chi/cors v1.2.1 h1:xEC8UT3Rlp2QuWNEr4Fs/c2EAGVKBwy/1vHx3bppil4=
 github.com/go-chi/cors v1.2.1/go.mod h1:sSbTewc+6wYHBBCW7ytsFSn836hqM7JxpglAy2Vzc58=
 github.com/go-chi/render v1.0.3 h1:AsXqd2a1/INaIfUSKq3G5uA8weYx20FOsM7uSoCyyt4=
 github.com/go-chi/render v1.0.3/go.mod h1:/gr3hVkmYR0YlEy3LxCuVRFzEu9Ruok+gFqbIofjao0=
+github.com/go-gost/relay v0.4.1-0.20230916134211-828f314ddfe7 h1:qAG1OyjvdA5h221CfFSS3J359V3d2E7dJWyP29QoDSI=
+github.com/go-gost/relay v0.4.1-0.20230916134211-828f314ddfe7/go.mod h1:lcX+23LCQ3khIeASBo+tJ/WbwXFO32/N5YN6ucuYTG8=
 github.com/google/btree v1.1.2 h1:xf4v41cLI2Z6FxbKm+8Bu+m8ifhj15JuZ9sa0jZCMUU=
 github.com/google/btree v1.1.2/go.mod h1:qOPhT0dTNdNzV6Z/lhRX0YXUafgPLFUh+gZMl761Gm4=
 github.com/google/uuid v1.3.1 h1:KjJaJ9iWZ3jOFZIf1Lqf4laDRCasjl0BCmnEGxkdLb4=

proxy/proto/proto.go

@@ -9,6 +9,7 @@ const (
 	Socks4
 	Socks5
 	Shadowsocks
+	Relay
 )
 
 type Proto uint8
@@ -27,6 +28,8 @@ func (proto Proto) String() string {
 		return "socks5"
 	case Shadowsocks:
 		return "ss"
+	case Relay:
+		return "relay"
 	default:
 		return fmt.Sprintf("proto(%d)", proto)
 	}

proxy/relay.go

@@ -0,0 +1,252 @@
+package proxy
+
+import (
+	"bytes"
+	"context"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"math"
+	"net"
+	"sync"
+
+	"github.com/go-gost/relay"
+
+	"github.com/xjasonlyu/tun2socks/v2/common/pool"
+	"github.com/xjasonlyu/tun2socks/v2/dialer"
+	M "github.com/xjasonlyu/tun2socks/v2/metadata"
+	"github.com/xjasonlyu/tun2socks/v2/proxy/proto"
+)
+
+var _ Proxy = (*Relay)(nil)
+
+type Relay struct {
+	*Base
+
+	user string
+	pass string
+
+	noDelay bool
+}
+
+func NewRelay(addr, user, pass string, noDelay bool) (*Relay, error) {
+	return &Relay{
+		Base: &Base{
+			addr:  addr,
+			proto: proto.Relay,
+		},
+		user:    user,
+		pass:    pass,
+		noDelay: noDelay,
+	}, nil
+}
+
+func (rl *Relay) DialContext(ctx context.Context, metadata *M.Metadata) (c net.Conn, err error) {
+	return rl.dialContext(ctx, metadata)
+}
+
+func (rl *Relay) DialUDP(metadata *M.Metadata) (net.PacketConn, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), tcpConnectTimeout)
+	defer cancel()
+
+	return rl.dialContext(ctx, metadata)
+}
+
+func (rl *Relay) dialContext(ctx context.Context, metadata *M.Metadata) (rc *relayConn, err error) {
+	var c net.Conn
+
+	c, err = dialer.DialContext(ctx, "tcp", rl.Addr())
+	if err != nil {
+		return nil, fmt.Errorf("connect to %s: %w", rl.Addr(), err)
+	}
+	setKeepAlive(c)
+
+	defer func(c net.Conn) {
+		safeConnClose(c, err)
+	}(c)
+
+	req := relay.Request{
+		Version: relay.Version1,
+		Cmd:     relay.CmdConnect,
+	}
+
+	if metadata.Network == M.UDP {
+		req.Cmd |= relay.FUDP
+		req.Features = append(req.Features, &relay.NetworkFeature{
+			Network: relay.NetworkUDP,
+		})
+	}
+
+	if rl.user != "" {
+		req.Features = append(req.Features, &relay.UserAuthFeature{
+			Username: rl.user,
+			Password: rl.pass,
+		})
+	}
+
+	req.Features = append(req.Features, serializeRelayAddr(metadata))
+
+	if rl.noDelay {
+		if _, err = req.WriteTo(c); err != nil {
+			return
+		}
+		if err = readRelayResponse(c); err != nil {
+			return
+		}
+	}
+
+	switch metadata.Network {
+	case M.TCP:
+		rc = newRelayConn(c, metadata.Addr(), rl.noDelay, false)
+		if !rl.noDelay {
+			if _, err = req.WriteTo(rc.wbuf); err != nil {
+				return
+			}
+		}
+	case M.UDP:
+		rc = newRelayConn(c, metadata.Addr(), rl.noDelay, true)
+		if !rl.noDelay {
+			if _, err = req.WriteTo(rc.wbuf); err != nil {
+				return
+			}
+		}
+	default:
+		err = fmt.Errorf("network %s is unsupported", metadata.Network)
+		return
+	}
+
+	return
+}
+
+type relayConn struct {
+	net.Conn
+	udp  bool
+	addr net.Addr
+	once sync.Once
+	wbuf *bytes.Buffer
+}
+
+func newRelayConn(c net.Conn, addr net.Addr, noDelay, udp bool) *relayConn {
+	rc := &relayConn{
+		Conn: c,
+		addr: addr,
+		udp:  udp,
+	}
+	if !noDelay {
+		rc.wbuf = &bytes.Buffer{}
+	}
+	return rc
+}
+
+func (rc *relayConn) ReadFrom(b []byte) (int, net.Addr, error) {
+	n, err := rc.Read(b)
+	return n, rc.addr, err
+}
+
+func (rc *relayConn) Read(b []byte) (n int, err error) {
+	rc.once.Do(func() {
+		if rc.wbuf != nil {
+			err = readRelayResponse(rc.Conn)
+		}
+	})
+	if err != nil {
+		return
+	}
+
+	if !rc.udp {
+		return rc.Conn.Read(b)
+	}
+
+	var bb [2]byte
+	_, err = io.ReadFull(rc.Conn, bb[:])
+	if err != nil {
+		return
+	}
+
+	dLen := int(binary.BigEndian.Uint16(bb[:]))
+	if len(b) >= dLen {
+		return io.ReadFull(rc.Conn, b[:dLen])
+	}
+
+	buf := pool.Get(dLen)
+	defer pool.Put(buf)
+	_, err = io.ReadFull(rc.Conn, buf)
+	n = copy(b, buf)
+
+	return
+}
+
+func (rc *relayConn) WriteTo(b []byte, _ net.Addr) (int, error) {
+	return rc.Write(b)
+}
+
+func (rc *relayConn) Write(b []byte) (int, error) {
+	if rc.udp {
+		return rc.udpWrite(b)
+	}
+	return rc.tcpWrite(b)
+}
+
+func (rc *relayConn) tcpWrite(b []byte) (n int, err error) {
+	if rc.wbuf != nil && rc.wbuf.Len() > 0 {
+		n = len(b)
+		rc.wbuf.Write(b)
+		_, err = rc.Conn.Write(rc.wbuf.Bytes())
+		rc.wbuf.Reset()
+		return
+	}
+	return rc.Conn.Write(b)
+}
+
+func (rc *relayConn) udpWrite(b []byte) (n int, err error) {
+	if len(b) > math.MaxUint16 {
+		err = errors.New("write: data maximum exceeded")
+		return
+	}
+
+	n = len(b)
+	if rc.wbuf != nil && rc.wbuf.Len() > 0 {
+		var bb [2]byte
+		binary.BigEndian.PutUint16(bb[:], uint16(len(b)))
+		rc.wbuf.Write(bb[:])
+		rc.wbuf.Write(b)
+		_, err = rc.wbuf.WriteTo(rc.Conn)
+		return
+	}
+
+	var bb [2]byte
+	binary.BigEndian.PutUint16(bb[:], uint16(len(b)))
+	_, err = rc.Conn.Write(bb[:])
+	if err != nil {
+		return
+	}
+	return rc.Conn.Write(b)
+}
+
+func readRelayResponse(r io.Reader) error {
+	resp := relay.Response{}
+	if _, err := resp.ReadFrom(r); err != nil {
+		return err
+	}
+	if resp.Version != relay.Version1 {
+		return relay.ErrBadVersion
+	}
+	if resp.Status != relay.StatusOK {
+		return fmt.Errorf("status %d", resp.Status)
+	}
+	return nil
+}
+
+func serializeRelayAddr(m *M.Metadata) *relay.AddrFeature {
+	af := &relay.AddrFeature{
+		Host: m.DstIP.String(),
+		Port: m.DstPort,
+	}
+	if m.DstIP.To4() != nil {
+		af.AType = relay.AddrIPv4
+	} else {
+		af.AType = relay.AddrIPv6
+	}
+	return af
+}