Feature: support relay (proxy chains) (#539)

README.md

@@ -255,6 +255,16 @@ proxies:
     # skip-cert-verify: true
 
 proxy-groups:
+  # relay chains the proxies. proxies shall not contain a proxy-group. No UDP support.
+  # Traffic: clash <-> http <-> vmess <-> ss1 <-> ss2 <-> Internet
+  - name: "relay"
+    type: relay
+    proxies:
+      - http
+      - vmess
+      - ss1
+      - ss2
+
   # url-test select which proxy will be used by benchmarking speed to a URL.
   - name: "auto"
     type: url-test

adapters/outbound/base.go

@@ -18,6 +18,7 @@ var (
 
 type Base struct {
 	name string
+	addr string
 	tp   C.AdapterType
 	udp  bool
 }
@@ -30,6 +31,10 @@ func (b *Base) Type() C.AdapterType {
 	return b.tp
 }
 
+func (b *Base) StreamConn(c net.Conn, metadata *C.Metadata) (net.Conn, error) {
+	return c, errors.New("no support")
+}
+
 func (b *Base) DialUDP(metadata *C.Metadata) (C.PacketConn, error) {
 	return nil, errors.New("no support")
 }
@@ -44,8 +49,12 @@ func (b *Base) MarshalJSON() ([]byte, error) {
 	})
 }
 
-func NewBase(name string, tp C.AdapterType, udp bool) *Base {
-	return &Base{name, tp, udp}
+func (b *Base) Addr() string {
+	return b.addr
+}
+
+func NewBase(name string, addr string, tp C.AdapterType, udp bool) *Base {
+	return &Base{name, addr, tp, udp}
 }
 
 type conn struct {
@@ -61,7 +70,7 @@ func (c *conn) AppendToChains(a C.ProxyAdapter) {
 	c.chain = append(c.chain, a.Name())
 }
 
-func newConn(c net.Conn, a C.ProxyAdapter) C.Conn {
+func NewConn(c net.Conn, a C.ProxyAdapter) C.Conn {
 	return &conn{c, []string{a.Name()}}
 }
 

adapters/outbound/direct.go

@@ -24,7 +24,7 @@ func (d *Direct) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn,
 		return nil, err
 	}
 	tcpKeepAlive(c)
-	return newConn(c, d), nil
+	return NewConn(c, d), nil
 }
 
 func (d *Direct) DialUDP(metadata *C.Metadata) (C.PacketConn, error) {

adapters/outbound/http.go

@@ -19,7 +19,6 @@ import (
 
 type Http struct {
 	*Base
-	addr      string
 	user      string
 	pass      string
 	tlsConfig *tls.Config
@@ -35,23 +34,35 @@ type HttpOption struct {
 	SkipCertVerify bool   `proxy:"skip-cert-verify,omitempty"`
 }
 
-func (h *Http) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
-	c, err := dialer.DialContext(ctx, "tcp", h.addr)
-	if err == nil && h.tlsConfig != nil {
+func (h *Http) StreamConn(c net.Conn, metadata *C.Metadata) (net.Conn, error) {
+	if h.tlsConfig != nil {
 		cc := tls.Client(c, h.tlsConfig)
-		err = cc.Handshake()
+		err := cc.Handshake()
 		c = cc
+		if err != nil {
+			return nil, fmt.Errorf("%s connect error: %w", h.addr, err)
+		}
 	}
 
+	if err := h.shakeHand(metadata, c); err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
+func (h *Http) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
+	c, err := dialer.DialContext(ctx, "tcp", h.addr)
 	if err != nil {
 		return nil, fmt.Errorf("%s connect error: %w", h.addr, err)
 	}
 	tcpKeepAlive(c)
-	if err := h.shakeHand(metadata, c); err != nil {
+
+	c, err = h.StreamConn(c, metadata)
+	if err != nil {
 		return nil, err
 	}
 
-	return newConn(c, h), nil
+	return NewConn(c, h), nil
 }
 
 func (h *Http) shakeHand(metadata *C.Metadata, rw io.ReadWriter) error {
@@ -113,9 +124,9 @@ func NewHttp(option HttpOption) *Http {
 	return &Http{
 		Base: &Base{
 			name: option.Name,
+			addr: net.JoinHostPort(option.Server, strconv.Itoa(option.Port)),
 			tp:   C.Http,
 		},
-		addr:      net.JoinHostPort(option.Server, strconv.Itoa(option.Port)),
 		user:      option.UserName,
 		pass:      option.Password,
 		tlsConfig: tlsConfig,

adapters/outbound/reject.go

@@ -15,7 +15,7 @@ type Reject struct {
 }
 
 func (r *Reject) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
-	return newConn(&NopConn{}, r), nil
+	return NewConn(&NopConn{}, r), nil
 }
 
 func (r *Reject) DialUDP(metadata *C.Metadata) (C.PacketConn, error) {

adapters/outbound/shadowsocks.go

@@ -21,7 +21,6 @@ import (
 
 type ShadowSocks struct {
 	*Base
-	server string
 	cipher core.Cipher
 
 	// obfs
@@ -60,28 +59,34 @@ type v2rayObfsOption struct {
 	Mux            bool              `obfs:"mux,omitempty"`
 }
 
-func (ss *ShadowSocks) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
-	c, err := dialer.DialContext(ctx, "tcp", ss.server)
-	if err != nil {
-		return nil, fmt.Errorf("%s connect error: %w", ss.server, err)
-	}
-	tcpKeepAlive(c)
+func (ss *ShadowSocks) StreamConn(c net.Conn, metadata *C.Metadata) (net.Conn, error) {
 	switch ss.obfsMode {
 	case "tls":
 		c = obfs.NewTLSObfs(c, ss.obfsOption.Host)
 	case "http":
-		_, port, _ := net.SplitHostPort(ss.server)
+		_, port, _ := net.SplitHostPort(ss.addr)
 		c = obfs.NewHTTPObfs(c, ss.obfsOption.Host, port)
 	case "websocket":
 		var err error
 		c, err = v2rayObfs.NewV2rayObfs(c, ss.v2rayOption)
 		if err != nil {
-			return nil, fmt.Errorf("%s connect error: %w", ss.server, err)
+			return nil, fmt.Errorf("%s connect error: %w", ss.addr, err)
 		}
 	}
 	c = ss.cipher.StreamConn(c)
-	_, err = c.Write(serializesSocksAddr(metadata))
-	return newConn(c, ss), err
+	_, err := c.Write(serializesSocksAddr(metadata))
+	return c, err
+}
+
+func (ss *ShadowSocks) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
+	c, err := dialer.DialContext(ctx, "tcp", ss.addr)
+	if err != nil {
+		return nil, fmt.Errorf("%s connect error: %w", ss.addr, err)
+	}
+	tcpKeepAlive(c)
+
+	c, err = ss.StreamConn(c, metadata)
+	return NewConn(c, ss), err
 }
 
 func (ss *ShadowSocks) DialUDP(metadata *C.Metadata) (C.PacketConn, error) {
@@ -90,7 +95,7 @@ func (ss *ShadowSocks) DialUDP(metadata *C.Metadata) (C.PacketConn, error) {
 		return nil, err
 	}
 
-	addr, err := resolveUDPAddr("udp", ss.server)
+	addr, err := resolveUDPAddr("udp", ss.addr)
 	if err != nil {
 		return nil, err
 	}
@@ -106,12 +111,12 @@ func (ss *ShadowSocks) MarshalJSON() ([]byte, error) {
 }
 
 func NewShadowSocks(option ShadowSocksOption) (*ShadowSocks, error) {
-	server := net.JoinHostPort(option.Server, strconv.Itoa(option.Port))
+	addr := net.JoinHostPort(option.Server, strconv.Itoa(option.Port))
 	cipher := option.Cipher
 	password := option.Password
 	ciph, err := core.PickCipher(cipher, nil, password)
 	if err != nil {
-		return nil, fmt.Errorf("ss %s initialize error: %w", server, err)
+		return nil, fmt.Errorf("ss %s initialize error: %w", addr, err)
 	}
 
 	var v2rayOption *v2rayObfs.Option
@@ -133,22 +138,22 @@ func NewShadowSocks(option ShadowSocksOption) (*ShadowSocks, error) {
 	if option.Plugin == "obfs" {
 		opts := simpleObfsOption{Host: "bing.com"}
 		if err := decoder.Decode(option.PluginOpts, &opts); err != nil {
-			return nil, fmt.Errorf("ss %s initialize obfs error: %w", server, err)
+			return nil, fmt.Errorf("ss %s initialize obfs error: %w", addr, err)
 		}
 
 		if opts.Mode != "tls" && opts.Mode != "http" {
-			return nil, fmt.Errorf("ss %s obfs mode error: %s", server, opts.Mode)
+			return nil, fmt.Errorf("ss %s obfs mode error: %s", addr, opts.Mode)
 		}
 		obfsMode = opts.Mode
 		obfsOption = &opts
 	} else if option.Plugin == "v2ray-plugin" {
 		opts := v2rayObfsOption{Host: "bing.com", Mux: true}
 		if err := decoder.Decode(option.PluginOpts, &opts); err != nil {
-			return nil, fmt.Errorf("ss %s initialize v2ray-plugin error: %w", server, err)
+			return nil, fmt.Errorf("ss %s initialize v2ray-plugin error: %w", addr, err)
 		}
 
 		if opts.Mode != "websocket" {
-			return nil, fmt.Errorf("ss %s obfs mode error: %s", server, opts.Mode)
+			return nil, fmt.Errorf("ss %s obfs mode error: %s", addr, opts.Mode)
 		}
 		obfsMode = opts.Mode
 
@@ -172,10 +177,10 @@ func NewShadowSocks(option ShadowSocksOption) (*ShadowSocks, error) {
 	return &ShadowSocks{
 		Base: &Base{
 			name: option.Name,
+			addr: addr,
 			tp:   C.Shadowsocks,
 			udp:  option.UDP,
 		},
-		server: server,
 		cipher: ciph,
 
 		obfsMode:    obfsMode,

adapters/outbound/snell.go

@@ -15,7 +15,6 @@ import (
 
 type Snell struct {
 	*Base
-	server     string
 	psk        []byte
 	obfsOption *simpleObfsOption
 }
@@ -28,45 +27,51 @@ type SnellOption struct {
 	ObfsOpts map[string]interface{} `proxy:"obfs-opts,omitempty"`
 }
 
-func (s *Snell) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
-	c, err := dialer.DialContext(ctx, "tcp", s.server)
-	if err != nil {
-		return nil, fmt.Errorf("%s connect error: %w", s.server, err)
-	}
-	tcpKeepAlive(c)
+func (s *Snell) StreamConn(c net.Conn, metadata *C.Metadata) (net.Conn, error) {
 	switch s.obfsOption.Mode {
 	case "tls":
 		c = obfs.NewTLSObfs(c, s.obfsOption.Host)
 	case "http":
-		_, port, _ := net.SplitHostPort(s.server)
+		_, port, _ := net.SplitHostPort(s.addr)
 		c = obfs.NewHTTPObfs(c, s.obfsOption.Host, port)
 	}
 	c = snell.StreamConn(c, s.psk)
 	port, _ := strconv.Atoi(metadata.DstPort)
-	err = snell.WriteHeader(c, metadata.String(), uint(port))
-	return newConn(c, s), err
+	err := snell.WriteHeader(c, metadata.String(), uint(port))
+	return c, err
+}
+
+func (s *Snell) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
+	c, err := dialer.DialContext(ctx, "tcp", s.addr)
+	if err != nil {
+		return nil, fmt.Errorf("%s connect error: %w", s.addr, err)
+	}
+	tcpKeepAlive(c)
+
+	c, err = s.StreamConn(c, metadata)
+	return NewConn(c, s), err
 }
 
 func NewSnell(option SnellOption) (*Snell, error) {
-	server := net.JoinHostPort(option.Server, strconv.Itoa(option.Port))
+	addr := net.JoinHostPort(option.Server, strconv.Itoa(option.Port))
 	psk := []byte(option.Psk)
 
 	decoder := structure.NewDecoder(structure.Option{TagName: "obfs", WeaklyTypedInput: true})
 	obfsOption := &simpleObfsOption{Host: "bing.com"}
 	if err := decoder.Decode(option.ObfsOpts, obfsOption); err != nil {
-		return nil, fmt.Errorf("snell %s initialize obfs error: %w", server, err)
+		return nil, fmt.Errorf("snell %s initialize obfs error: %w", addr, err)
 	}
 
 	if obfsOption.Mode != "tls" && obfsOption.Mode != "http" {
-		return nil, fmt.Errorf("snell %s obfs mode error: %s", server, obfsOption.Mode)
+		return nil, fmt.Errorf("snell %s obfs mode error: %s", addr, obfsOption.Mode)
 	}
 
 	return &Snell{
 		Base: &Base{
 			name: option.Name,
+			addr: addr,
 			tp:   C.Snell,
 		},
-		server:     server,
 		psk:        psk,
 		obfsOption: obfsOption,
 	}, nil

adapters/outbound/socks5.go

@@ -17,7 +17,6 @@ import (
 
 type Socks5 struct {
 	*Base
-	addr           string
 	user           string
 	pass           string
 	tls            bool
@@ -36,19 +35,16 @@ type Socks5Option struct {
 	SkipCertVerify bool   `proxy:"skip-cert-verify,omitempty"`
 }
 
-func (ss *Socks5) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
-	c, err := dialer.DialContext(ctx, "tcp", ss.addr)
-
-	if err == nil && ss.tls {
+func (ss *Socks5) StreamConn(c net.Conn, metadata *C.Metadata) (net.Conn, error) {
+	if ss.tls {
 		cc := tls.Client(c, ss.tlsConfig)
-		err = cc.Handshake()
+		err := cc.Handshake()
 		c = cc
+		if err != nil {
+			return nil, fmt.Errorf("%s connect error: %w", ss.addr, err)
+		}
 	}
 
-	if err != nil {
-		return nil, fmt.Errorf("%s connect error: %w", ss.addr, err)
-	}
-	tcpKeepAlive(c)
 	var user *socks5.User
 	if ss.user != "" {
 		user = &socks5.User{
@@ -59,7 +55,22 @@ func (ss *Socks5) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn
 	if _, err := socks5.ClientHandshake(c, serializesSocksAddr(metadata), socks5.CmdConnect, user); err != nil {
 		return nil, err
 	}
-	return newConn(c, ss), nil
+	return c, nil
+}
+
+func (ss *Socks5) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
+	c, err := dialer.DialContext(ctx, "tcp", ss.addr)
+	if err != nil {
+		return nil, fmt.Errorf("%s connect error: %w", ss.addr, err)
+	}
+	tcpKeepAlive(c)
+
+	c, err = ss.StreamConn(c, metadata)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewConn(c, ss), nil
 }
 
 func (ss *Socks5) DialUDP(metadata *C.Metadata) (_ C.PacketConn, err error) {
@@ -127,10 +138,10 @@ func NewSocks5(option Socks5Option) *Socks5 {
 	return &Socks5{
 		Base: &Base{
 			name: option.Name,
+			addr: net.JoinHostPort(option.Server, strconv.Itoa(option.Port)),
 			tp:   C.Socks5,
 			udp:  option.UDP,
 		},
-		addr:           net.JoinHostPort(option.Server, strconv.Itoa(option.Port)),
 		user:           option.UserName,
 		pass:           option.Password,
 		tls:            option.TLS,