Feature: support trojan

adapters/outbound/parser.go

@@ -52,6 +52,13 @@ func ParseProxy(mapping map[string]interface{}) (C.Proxy, error) {
 			break
 		}
 		proxy, err = NewSnell(*snellOption)
+	case "trojan":
+		trojanOption := &TrojanOption{}
+		err = decoder.Decode(mapping, trojanOption)
+		if err != nil {
+			break
+		}
+		proxy, err = NewTrojan(*trojanOption)
 	default:
 		return nil, fmt.Errorf("Unsupport proxy type: %s", proxyType)
 	}

adapters/outbound/trojan.go

@@ -0,0 +1,107 @@
+package outbound
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net"
+	"strconv"
+
+	"github.com/Dreamacro/clash/component/dialer"
+	"github.com/Dreamacro/clash/component/trojan"
+	C "github.com/Dreamacro/clash/constant"
+)
+
+type Trojan struct {
+	*Base
+	server   string
+	instance *trojan.Trojan
+}
+
+type TrojanOption struct {
+	Name           string   `proxy:"name"`
+	Server         string   `proxy:"server"`
+	Port           int      `proxy:"port"`
+	Password       string   `proxy:"password"`
+	ALPN           []string `proxy:"alpn,omitempty"`
+	SNI            string   `proxy:"sni,omitempty"`
+	SkipCertVerify bool     `proxy:"skip-cert-verify,omitempty"`
+	UDP            bool     `proxy:"udp,omitempty"`
+}
+
+func (t *Trojan) DialContext(ctx context.Context, metadata *C.Metadata) (C.Conn, error) {
+	c, err := dialer.DialContext(ctx, "tcp", t.server)
+	if err != nil {
+		return nil, fmt.Errorf("%s connect error: %w", t.server, err)
+	}
+	tcpKeepAlive(c)
+	c, err = t.instance.StreamConn(c)
+	if err != nil {
+		return nil, fmt.Errorf("%s connect error: %w", t.server, err)
+	}
+
+	err = t.instance.WriteHeader(c, trojan.CommandTCP, serializesSocksAddr(metadata))
+	return newConn(c, t), err
+}
+
+func (t *Trojan) DialUDP(metadata *C.Metadata) (C.PacketConn, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), tcpTimeout)
+	defer cancel()
+	c, err := dialer.DialContext(ctx, "tcp", t.server)
+	if err != nil {
+		return nil, fmt.Errorf("%s connect error: %w", t.server, err)
+	}
+	tcpKeepAlive(c)
+	c, err = t.instance.StreamConn(c)
+	if err != nil {
+		return nil, fmt.Errorf("%s connect error: %w", t.server, err)
+	}
+
+	err = t.instance.WriteHeader(c, trojan.CommandUDP, serializesSocksAddr(metadata))
+	if err != nil {
+		return nil, err
+	}
+
+	pc := t.instance.PacketConn(c)
+	return newPacketConn(&trojanPacketConn{pc, c}, t), err
+}
+
+func (t *Trojan) MarshalJSON() ([]byte, error) {
+	return json.Marshal(map[string]string{
+		"type": t.Type().String(),
+	})
+}
+
+func NewTrojan(option TrojanOption) (*Trojan, error) {
+	server := net.JoinHostPort(option.Server, strconv.Itoa(option.Port))
+
+	tOption := &trojan.Option{
+		Password:       option.Password,
+		ALPN:           option.ALPN,
+		ServerName:     option.Server,
+		SkipCertVerify: option.SkipCertVerify,
+	}
+
+	if option.SNI != "" {
+		tOption.ServerName = option.SNI
+	}
+
+	return &Trojan{
+		Base: &Base{
+			name: option.Name,
+			tp:   C.Trojan,
+			udp:  option.UDP,
+		},
+		server:   server,
+		instance: trojan.New(tOption),
+	}, nil
+}
+
+type trojanPacketConn struct {
+	net.PacketConn
+	conn net.Conn
+}
+
+func (tpc *trojanPacketConn) WriteWithMetadata(p []byte, metadata *C.Metadata) (n int, err error) {
+	return trojan.WritePacket(tpc.conn, serializesSocksAddr(metadata), p)
+}