Feature: support trojan

component/trojan/trojan.go

@@ -0,0 +1,144 @@
+package trojan
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"crypto/tls"
+	"encoding/binary"
+	"encoding/hex"
+	"errors"
+	"net"
+	"sync"
+
+	"github.com/Dreamacro/clash/component/socks5"
+)
+
+var (
+	defaultALPN = []string{"h2", "http/1.1"}
+	crlf        = []byte{'\r', '\n'}
+
+	bufPool = sync.Pool{New: func() interface{} { return &bytes.Buffer{} }}
+)
+
+type Command = byte
+
+var (
+	CommandTCP byte = 1
+	CommandUDP byte = 3
+)
+
+type Option struct {
+	Password       string
+	ALPN           []string
+	ServerName     string
+	SkipCertVerify bool
+}
+
+type Trojan struct {
+	option      *Option
+	hexPassword []byte
+}
+
+func (t *Trojan) StreamConn(conn net.Conn) (net.Conn, error) {
+	alpn := defaultALPN
+	if len(t.option.ALPN) != 0 {
+		alpn = t.option.ALPN
+	}
+
+	tlsConfig := &tls.Config{
+		NextProtos:         alpn,
+		MinVersion:         tls.VersionTLS12,
+		InsecureSkipVerify: t.option.SkipCertVerify,
+		ServerName:         t.option.ServerName,
+	}
+
+	tlsConn := tls.Client(conn, tlsConfig)
+	if err := tlsConn.Handshake(); err != nil {
+		return nil, err
+	}
+
+	return tlsConn, nil
+}
+
+func (t *Trojan) WriteHeader(conn net.Conn, command Command, socks5Addr []byte) error {
+	buf := bufPool.Get().(*bytes.Buffer)
+	defer buf.Reset()
+	defer bufPool.Put(buf)
+
+	buf.Write(t.hexPassword)
+	buf.Write(crlf)
+
+	buf.WriteByte(command)
+	buf.Write(socks5Addr)
+	buf.Write(crlf)
+
+	_, err := conn.Write(buf.Bytes())
+	return err
+}
+
+func (t *Trojan) PacketConn(conn net.Conn) net.PacketConn {
+	return &PacketConn{conn}
+}
+
+func WritePacket(conn net.Conn, socks5Addr, payload []byte) (int, error) {
+	buf := bufPool.Get().(*bytes.Buffer)
+	defer buf.Reset()
+	defer bufPool.Put(buf)
+
+	buf.Write(socks5Addr)
+	binary.Write(buf, binary.BigEndian, uint16(len(payload)))
+	buf.Write(crlf)
+	buf.Write(payload)
+
+	return conn.Write(buf.Bytes())
+}
+
+func DecodePacket(payload []byte) (net.Addr, []byte, error) {
+	addr := socks5.SplitAddr(payload)
+	if addr == nil {
+		return nil, nil, errors.New("split addr error")
+	}
+
+	buf := payload[len(addr):]
+	if len(buf) <= 4 {
+		return nil, nil, errors.New("packet invalid")
+	}
+
+	length := binary.BigEndian.Uint16(buf[:2])
+	if len(buf) < 4+int(length) {
+		return nil, nil, errors.New("packet invalid")
+	}
+
+	return addr.UDPAddr(), buf[4 : 4+length], nil
+}
+
+func New(option *Option) *Trojan {
+	return &Trojan{option, hexSha224([]byte(option.Password))}
+}
+
+type PacketConn struct {
+	net.Conn
+}
+
+func (pc *PacketConn) WriteTo(b []byte, addr net.Addr) (int, error) {
+	return WritePacket(pc, socks5.ParseAddr(addr.String()), b)
+}
+
+func (pc *PacketConn) ReadFrom(b []byte) (int, net.Addr, error) {
+	n, err := pc.Conn.Read(b)
+	addr, payload, err := DecodePacket(b)
+	if err != nil {
+		return n, nil, err
+	}
+
+	copy(b, payload)
+	return len(payload), addr, nil
+}
+
+func hexSha224(data []byte) []byte {
+	buf := make([]byte, 56)
+	hash := sha256.New224()
+	hash.Write(data)
+	hex.Encode(buf, hash.Sum(nil))
+	return buf
+}