Feature: support outbound socks5 udp

README.md

@@ -230,5 +230,5 @@ https://clash.gitbook.io/
 
 - [x] Complementing the necessary rule operators
 - [x] Redir proxy
-- [ ] UDP support (vmess, outbound socks5)
+- [ ] UDP support (vmess)
 - [ ] Connection manager

adapters/inbound/socket.go

@@ -3,8 +3,8 @@ package adapters
 import (
 	"net"
 
+	"github.com/Dreamacro/clash/component/socks5"
 	C "github.com/Dreamacro/clash/constant"
-	"github.com/Dreamacro/go-shadowsocks2/socks"
 )
 
 // SocketAdapter is a adapter for socks and redir connection
@@ -19,7 +19,7 @@ func (s *SocketAdapter) Metadata() *C.Metadata {
 }
 
 // NewSocket is SocketAdapter generator
-func NewSocket(target socks.Addr, conn net.Conn, source C.SourceType, netType C.NetWork) *SocketAdapter {
+func NewSocket(target socks5.Addr, conn net.Conn, source C.SourceType, netType C.NetWork) *SocketAdapter {
 	metadata := parseSocksAddr(target)
 	metadata.NetWork = netType
 	metadata.Source = source

adapters/inbound/util.go

@@ -5,24 +5,24 @@ import (
 	"net/http"
 	"strconv"
 
+	"github.com/Dreamacro/clash/component/socks5"
 	C "github.com/Dreamacro/clash/constant"
-	"github.com/Dreamacro/go-shadowsocks2/socks"
 )
 
-func parseSocksAddr(target socks.Addr) *C.Metadata {
+func parseSocksAddr(target socks5.Addr) *C.Metadata {
 	metadata := &C.Metadata{
 		AddrType: int(target[0]),
 	}
 
 	switch target[0] {
-	case socks.AtypDomainName:
+	case socks5.AtypDomainName:
 		metadata.Host = string(target[2 : 2+target[1]])
 		metadata.Port = strconv.Itoa((int(target[2+target[1]]) << 8) | int(target[2+target[1]+1]))
-	case socks.AtypIPv4:
+	case socks5.AtypIPv4:
 		ip := net.IP(target[1 : 1+net.IPv4len])
 		metadata.IP = &ip
 		metadata.Port = strconv.Itoa((int(target[1+net.IPv4len]) << 8) | int(target[1+net.IPv4len+1]))
-	case socks.AtypIPv6:
+	case socks5.AtypIPv6:
 		ip := net.IP(target[1 : 1+net.IPv6len])
 		metadata.IP = &ip
 		metadata.Port = strconv.Itoa((int(target[1+net.IPv6len]) << 8) | int(target[1+net.IPv6len+1]))

adapters/outbound/shadowsocks.go

@@ -1,7 +1,6 @@
 package adapters
 
 import (
-	"bytes"
 	"crypto/tls"
 	"encoding/json"
 	"fmt"
@@ -11,11 +10,11 @@ import (
 	"github.com/Dreamacro/clash/common/pool"
 	"github.com/Dreamacro/clash/common/structure"
 	obfs "github.com/Dreamacro/clash/component/simple-obfs"
+	"github.com/Dreamacro/clash/component/socks5"
 	v2rayObfs "github.com/Dreamacro/clash/component/v2ray-plugin"
 	C "github.com/Dreamacro/clash/constant"
 
 	"github.com/Dreamacro/go-shadowsocks2/core"
-	"github.com/Dreamacro/go-shadowsocks2/socks"
 )
 
 type ShadowSocks struct {
@@ -177,26 +176,6 @@ func NewShadowSocks(option ShadowSocksOption) (*ShadowSocks, error) {
 	}, nil
 }
 
-func serializesSocksAddr(metadata *C.Metadata) []byte {
-	var buf [][]byte
-	aType := uint8(metadata.AddrType)
-	p, _ := strconv.Atoi(metadata.Port)
-	port := []byte{uint8(p >> 8), uint8(p & 0xff)}
-	switch metadata.AddrType {
-	case socks.AtypDomainName:
-		len := uint8(len(metadata.Host))
-		host := []byte(metadata.Host)
-		buf = [][]byte{{aType, len}, host, port}
-	case socks.AtypIPv4:
-		host := metadata.IP.To4()
-		buf = [][]byte{{aType}, host, port}
-	case socks.AtypIPv6:
-		host := metadata.IP.To16()
-		buf = [][]byte{{aType}, host, port}
-	}
-	return bytes.Join(buf, nil)
-}
-
 type ssUDPConn struct {
 	net.PacketConn
 	rAddr net.Addr
@@ -205,7 +184,7 @@ type ssUDPConn struct {
 func (uc *ssUDPConn) WriteTo(b []byte, addr net.Addr) (int, error) {
 	buf := pool.BufPool.Get().([]byte)
 	defer pool.BufPool.Put(buf[:cap(buf)])
-	rAddr := socks.ParseAddr(uc.rAddr.String())
+	rAddr := socks5.ParseAddr(uc.rAddr.String())
 	copy(buf[len(rAddr):], b)
 	copy(buf, rAddr)
 	return uc.PacketConn.WriteTo(buf[:len(rAddr)+len(b)], addr)
@@ -213,7 +192,7 @@ func (uc *ssUDPConn) WriteTo(b []byte, addr net.Addr) (int, error) {
 
 func (uc *ssUDPConn) ReadFrom(b []byte) (int, net.Addr, error) {
 	n, a, e := uc.PacketConn.ReadFrom(b)
-	addr := socks.SplitAddr(b[:n])
+	addr := socks5.SplitAddr(b[:n])
 	copy(b, b[len(addr):])
 	return n - len(addr), a, e
 }

adapters/outbound/socks5.go

@@ -1,17 +1,13 @@
 package adapters
 
 import (
-	"bytes"
 	"crypto/tls"
-	"errors"
 	"fmt"
-	"io"
 	"net"
 	"strconv"
 
+	"github.com/Dreamacro/clash/component/socks5"
 	C "github.com/Dreamacro/clash/constant"
-
-	"github.com/Dreamacro/go-shadowsocks2/socks"
 )
 
 type Socks5 struct {
@@ -48,69 +44,44 @@ func (ss *Socks5) Dial(metadata *C.Metadata) (net.Conn, error) {
 		return nil, fmt.Errorf("%s connect error", ss.addr)
 	}
 	tcpKeepAlive(c)
-	if err := ss.shakeHand(metadata, c); err != nil {
+	var user *socks5.User
+	if ss.user != "" {
+		user = &socks5.User{
+			Username: ss.user,
+			Password: ss.pass,
+		}
+	}
+	if err := socks5.ClientHandshake(c, serializesSocksAddr(metadata), socks5.CmdConnect, user); err != nil {
 		return nil, err
 	}
 	return c, nil
 }
 
-func (ss *Socks5) shakeHand(metadata *C.Metadata, rw io.ReadWriter) error {
+func (ss *Socks5) DialUDP(metadata *C.Metadata) (net.PacketConn, net.Addr, error) {
-	buf := make([]byte, socks.MaxAddrLen)
+	c, err := net.DialTimeout("tcp", ss.addr, tcpTimeout)
-	var err error
 
-	// VER, NMETHODS, METHODS
+	if err == nil && ss.tls {
-	if len(ss.user) > 0 {
+		cc := tls.Client(c, ss.tlsConfig)
-		_, err = rw.Write([]byte{5, 1, 2})
+		err = cc.Handshake()
-	} else {
+		c = cc
-		_, err = rw.Write([]byte{5, 1, 0})
 	}
+
 	if err != nil {
-		return err
+		return nil, nil, fmt.Errorf("%s connect error", ss.addr)
+	}
+	tcpKeepAlive(c)
+	var user *socks5.User
+	if ss.user != "" {
+		user = &socks5.User{
+			Username: ss.user,
+			Password: ss.pass,
+		}
 	}
 
-	// VER, METHOD
+	if err := socks5.ClientHandshake(c, serializesSocksAddr(metadata), socks5.CmdUDPAssociate, user); err != nil {
-	if _, err := io.ReadFull(rw, buf[:2]); err != nil {
+		return nil, nil, err
-		return err
 	}
-
+	return &fakeUDPConn{Conn: c}, c.LocalAddr(), nil
-	if buf[0] != 5 {
-		return errors.New("SOCKS version error")
-	}
-
-	if buf[1] == 2 {
-		// password protocol version
-		authMsg := &bytes.Buffer{}
-		authMsg.WriteByte(1)
-		authMsg.WriteByte(uint8(len(ss.user)))
-		authMsg.WriteString(ss.user)
-		authMsg.WriteByte(uint8(len(ss.pass)))
-		authMsg.WriteString(ss.pass)
-
-		if _, err := rw.Write(authMsg.Bytes()); err != nil {
-			return err
-		}
-
-		if _, err := io.ReadFull(rw, buf[:2]); err != nil {
-			return err
-		}
-
-		if buf[1] != 0 {
-			return errors.New("rejected username/password")
-		}
-	} else if buf[1] != 0 {
-		return errors.New("SOCKS need auth")
-	}
-
-	// VER, CMD, RSV, ADDR
-	if _, err := rw.Write(bytes.Join([][]byte{{5, 1, 0}, serializesSocksAddr(metadata)}, []byte(""))); err != nil {
-		return err
-	}
-
-	if _, err := io.ReadFull(rw, buf[:10]); err != nil {
-		return err
-	}
-
-	return nil
 }
 
 func NewSocks5(option Socks5Option) *Socks5 {

adapters/outbound/util.go

@@ -1,13 +1,16 @@
 package adapters
 
 import (
+	"bytes"
 	"crypto/tls"
 	"fmt"
 	"net"
 	"net/url"
+	"strconv"
 	"sync"
 	"time"
 
+	"github.com/Dreamacro/clash/component/socks5"
 	C "github.com/Dreamacro/clash/constant"
 )
 
@@ -60,3 +63,36 @@ func getClientSessionCache() tls.ClientSessionCache {
 	})
 	return globalClientSessionCache
 }
+
+func serializesSocksAddr(metadata *C.Metadata) []byte {
+	var buf [][]byte
+	aType := uint8(metadata.AddrType)
+	p, _ := strconv.Atoi(metadata.Port)
+	port := []byte{uint8(p >> 8), uint8(p & 0xff)}
+	switch metadata.AddrType {
+	case socks5.AtypDomainName:
+		len := uint8(len(metadata.Host))
+		host := []byte(metadata.Host)
+		buf = [][]byte{{aType, len}, host, port}
+	case socks5.AtypIPv4:
+		host := metadata.IP.To4()
+		buf = [][]byte{{aType}, host, port}
+	case socks5.AtypIPv6:
+		host := metadata.IP.To16()
+		buf = [][]byte{{aType}, host, port}
+	}
+	return bytes.Join(buf, nil)
+}
+
+type fakeUDPConn struct {
+	net.Conn
+}
+
+func (fuc *fakeUDPConn) WriteTo(b []byte, addr net.Addr) (int, error) {
+	return fuc.Conn.Write(b)
+}
+
+func (fuc *fakeUDPConn) ReadFrom(b []byte) (int, net.Addr, error) {
+	n, err := fuc.Conn.Read(b)
+	return n, fuc.RemoteAddr(), err
+}

component/socks5/socks5.go

@@ -0,0 +1,246 @@
+package socks5
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"net"
+	"strconv"
+)
+
+// Error represents a SOCKS error
+type Error byte
+
+func (err Error) Error() string {
+	return "SOCKS error: " + strconv.Itoa(int(err))
+}
+
+// Command is request commands as defined in RFC 1928 section 4.
+type Command = uint8
+
+// SOCKS request commands as defined in RFC 1928 section 4.
+const (
+	CmdConnect      Command = 1
+	CmdBind         Command = 2
+	CmdUDPAssociate Command = 3
+)
+
+// SOCKS address types as defined in RFC 1928 section 5.
+const (
+	AtypIPv4       = 1
+	AtypDomainName = 3
+	AtypIPv6       = 4
+)
+
+// MaxAddrLen is the maximum size of SOCKS address in bytes.
+const MaxAddrLen = 1 + 1 + 255 + 2
+
+// Addr represents a SOCKS address as defined in RFC 1928 section 5.
+type Addr = []byte
+
+// SOCKS errors as defined in RFC 1928 section 6.
+const (
+	ErrGeneralFailure       = Error(1)
+	ErrConnectionNotAllowed = Error(2)
+	ErrNetworkUnreachable   = Error(3)
+	ErrHostUnreachable      = Error(4)
+	ErrConnectionRefused    = Error(5)
+	ErrTTLExpired           = Error(6)
+	ErrCommandNotSupported  = Error(7)
+	ErrAddressNotSupported  = Error(8)
+)
+
+type User struct {
+	Username string
+	Password string
+}
+
+// ServerHandshake fast-tracks SOCKS initialization to get target address to connect on server side.
+func ServerHandshake(rw io.ReadWriter) (addr Addr, command Command, err error) {
+	// Read RFC 1928 for request and reply structure and sizes.
+	buf := make([]byte, MaxAddrLen)
+	// read VER, NMETHODS, METHODS
+	if _, err = io.ReadFull(rw, buf[:2]); err != nil {
+		return
+	}
+	nmethods := buf[1]
+	if _, err = io.ReadFull(rw, buf[:nmethods]); err != nil {
+		return
+	}
+	// write VER METHOD
+	if _, err = rw.Write([]byte{5, 0}); err != nil {
+		return
+	}
+	// read VER CMD RSV ATYP DST.ADDR DST.PORT
+	if _, err = io.ReadFull(rw, buf[:3]); err != nil {
+		return
+	}
+
+	if buf[1] != CmdConnect && buf[1] != CmdUDPAssociate {
+		err = ErrCommandNotSupported
+		return
+	}
+
+	command = buf[1]
+	addr, err = readAddr(rw, buf)
+	if err != nil {
+		return
+	}
+	// write VER REP RSV ATYP BND.ADDR BND.PORT
+	_, err = rw.Write([]byte{5, 0, 0, 1, 0, 0, 0, 0, 0, 0})
+	return
+}
+
+// ClientHandshake fast-tracks SOCKS initialization to get target address to connect on client side.
+func ClientHandshake(rw io.ReadWriter, addr Addr, cammand Command, user *User) error {
+	buf := make([]byte, MaxAddrLen)
+	var err error
+
+	// VER, NMETHODS, METHODS
+	if user != nil {
+		_, err = rw.Write([]byte{5, 1, 2})
+	} else {
+		_, err = rw.Write([]byte{5, 1, 0})
+	}
+	if err != nil {
+		return err
+	}
+
+	// VER, METHOD
+	if _, err := io.ReadFull(rw, buf[:2]); err != nil {
+		return err
+	}
+
+	if buf[0] != 5 {
+		return errors.New("SOCKS version error")
+	}
+
+	if buf[1] == 2 {
+		// password protocol version
+		authMsg := &bytes.Buffer{}
+		authMsg.WriteByte(1)
+		authMsg.WriteByte(uint8(len(user.Username)))
+		authMsg.WriteString(user.Username)
+		authMsg.WriteByte(uint8(len(user.Password)))
+		authMsg.WriteString(user.Password)
+
+		if _, err := rw.Write(authMsg.Bytes()); err != nil {
+			return err
+		}
+
+		if _, err := io.ReadFull(rw, buf[:2]); err != nil {
+			return err
+		}
+
+		if buf[1] != 0 {
+			return errors.New("rejected username/password")
+		}
+	} else if buf[1] != 0 {
+		return errors.New("SOCKS need auth")
+	}
+
+	// VER, CMD, RSV, ADDR
+	if _, err := rw.Write(bytes.Join([][]byte{{5, cammand, 0}, addr}, []byte(""))); err != nil {
+		return err
+	}
+
+	if _, err := io.ReadFull(rw, buf[:10]); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func readAddr(r io.Reader, b []byte) (Addr, error) {
+	if len(b) < MaxAddrLen {
+		return nil, io.ErrShortBuffer
+	}
+	_, err := io.ReadFull(r, b[:1]) // read 1st byte for address type
+	if err != nil {
+		return nil, err
+	}
+
+	switch b[0] {
+	case AtypDomainName:
+		_, err = io.ReadFull(r, b[1:2]) // read 2nd byte for domain length
+		if err != nil {
+			return nil, err
+		}
+		_, err = io.ReadFull(r, b[2:2+b[1]+2])
+		return b[:1+1+b[1]+2], err
+	case AtypIPv4:
+		_, err = io.ReadFull(r, b[1:1+net.IPv4len+2])
+		return b[:1+net.IPv4len+2], err
+	case AtypIPv6:
+		_, err = io.ReadFull(r, b[1:1+net.IPv6len+2])
+		return b[:1+net.IPv6len+2], err
+	}
+
+	return nil, ErrAddressNotSupported
+}
+
+// SplitAddr slices a SOCKS address from beginning of b. Returns nil if failed.
+func SplitAddr(b []byte) Addr {
+	addrLen := 1
+	if len(b) < addrLen {
+		return nil
+	}
+
+	switch b[0] {
+	case AtypDomainName:
+		if len(b) < 2 {
+			return nil
+		}
+		addrLen = 1 + 1 + int(b[1]) + 2
+	case AtypIPv4:
+		addrLen = 1 + net.IPv4len + 2
+	case AtypIPv6:
+		addrLen = 1 + net.IPv6len + 2
+	default:
+		return nil
+
+	}
+
+	if len(b) < addrLen {
+		return nil
+	}
+
+	return b[:addrLen]
+}
+
+// ParseAddr parses the address in string s. Returns nil if failed.
+func ParseAddr(s string) Addr {
+	var addr Addr
+	host, port, err := net.SplitHostPort(s)
+	if err != nil {
+		return nil
+	}
+	if ip := net.ParseIP(host); ip != nil {
+		if ip4 := ip.To4(); ip4 != nil {
+			addr = make([]byte, 1+net.IPv4len+2)
+			addr[0] = AtypIPv4
+			copy(addr[1:], ip4)
+		} else {
+			addr = make([]byte, 1+net.IPv6len+2)
+			addr[0] = AtypIPv6
+			copy(addr[1:], ip)
+		}
+	} else {
+		if len(host) > 255 {
+			return nil
+		}
+		addr = make([]byte, 1+1+len(host)+2)
+		addr[0] = AtypDomainName
+		addr[1] = byte(len(host))
+		copy(addr[2:], host)
+	}
+
+	portnum, err := strconv.ParseUint(port, 10, 16)
+	if err != nil {
+		return nil
+	}
+
+	addr[len(addr)-2], addr[len(addr)-1] = byte(portnum>>8), byte(portnum)
+
+	return addr
+}

proxy/redir/tcp_darwin.go

@@ -5,10 +5,10 @@ import (
 	"syscall"
 	"unsafe"
 
-	"github.com/Dreamacro/go-shadowsocks2/socks"
+	"github.com/Dreamacro/clash/component/socks5"
 )
 
-func parserPacket(c net.Conn) (socks.Addr, error) {
+func parserPacket(c net.Conn) (socks5.Addr, error) {
 	const (
 		PfInout     = 0
 		PfIn        = 1
@@ -51,7 +51,7 @@ func parserPacket(c net.Conn) (socks.Addr, error) {
 	}
 
 	addr := make([]byte, 1+net.IPv4len+2)
-	addr[0] = socks.AtypIPv4
+	addr[0] = socks5.AtypIPv4
 	copy(addr[1:1+net.IPv4len], nl.rdaddr[:4])
 	copy(addr[1+net.IPv4len:], nl.rdxport[:2])
 	return addr, nil

proxy/redir/tcp_freebsd.go

@@ -6,7 +6,7 @@ import (
 	"syscall"
 	"unsafe"
 
-	"github.com/Dreamacro/go-shadowsocks2/socks"
+	"github.com/Dreamacro/clash/component/socks5"
 )
 
 const (
@@ -14,7 +14,7 @@ const (
 	IP6T_SO_ORIGINAL_DST = 80 // from linux/include/uapi/linux/netfilter_ipv6/ip6_tables.h
 )
 
-func parserPacket(conn net.Conn) (socks.Addr, error) {
+func parserPacket(conn net.Conn) (socks5.Addr, error) {
 	c, ok := conn.(*net.TCPConn)
 	if !ok {
 		return nil, errors.New("only work with TCP connection")
@@ -25,7 +25,7 @@ func parserPacket(conn net.Conn) (socks.Addr, error) {
 		return nil, err
 	}
 
-	var addr socks.Addr
+	var addr socks5.Addr
 
 	rc.Control(func(fd uintptr) {
 		addr, err = getorigdst(fd)
@@ -35,7 +35,7 @@ func parserPacket(conn net.Conn) (socks.Addr, error) {
 }
 
 // Call getorigdst() from linux/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
-func getorigdst(fd uintptr) (socks.Addr, error) {
+func getorigdst(fd uintptr) (socks5.Addr, error) {
 	raw := syscall.RawSockaddrInet4{}
 	siz := unsafe.Sizeof(raw)
 	_, _, err := syscall.Syscall6(syscall.SYS_GETSOCKOPT, fd, syscall.IPPROTO_IP, SO_ORIGINAL_DST, uintptr(unsafe.Pointer(&raw)), uintptr(unsafe.Pointer(&siz)), 0)
@@ -44,7 +44,7 @@ func getorigdst(fd uintptr) (socks.Addr, error) {
 	}
 
 	addr := make([]byte, 1+net.IPv4len+2)
-	addr[0] = socks.AtypIPv4
+	addr[0] = socks5.AtypIPv4
 	copy(addr[1:1+net.IPv4len], raw.Addr[:])
 	port := (*[2]byte)(unsafe.Pointer(&raw.Port)) // big-endian
 	addr[1+net.IPv4len], addr[1+net.IPv4len+1] = port[0], port[1]

proxy/redir/tcp_linux.go

@@ -6,7 +6,7 @@ import (
 	"syscall"
 	"unsafe"
 
-	"github.com/Dreamacro/go-shadowsocks2/socks"
+	"github.com/Dreamacro/clash/component/socks5"
 )
 
 const (
@@ -14,7 +14,7 @@ const (
 	IP6T_SO_ORIGINAL_DST = 80 // from linux/include/uapi/linux/netfilter_ipv6/ip6_tables.h
 )
 
-func parserPacket(conn net.Conn) (socks.Addr, error) {
+func parserPacket(conn net.Conn) (socks5.Addr, error) {
 	c, ok := conn.(*net.TCPConn)
 	if !ok {
 		return nil, errors.New("only work with TCP connection")
@@ -25,7 +25,7 @@ func parserPacket(conn net.Conn) (socks.Addr, error) {
 		return nil, err
 	}
 
-	var addr socks.Addr
+	var addr socks5.Addr
 
 	rc.Control(func(fd uintptr) {
 		addr, err = getorigdst(fd)
@@ -35,7 +35,7 @@ func parserPacket(conn net.Conn) (socks.Addr, error) {
 }
 
 // Call getorigdst() from linux/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
-func getorigdst(fd uintptr) (socks.Addr, error) {
+func getorigdst(fd uintptr) (socks5.Addr, error) {
 	raw := syscall.RawSockaddrInet4{}
 	siz := unsafe.Sizeof(raw)
 	if err := socketcall(GETSOCKOPT, fd, syscall.IPPROTO_IP, SO_ORIGINAL_DST, uintptr(unsafe.Pointer(&raw)), uintptr(unsafe.Pointer(&siz)), 0); err != nil {
@@ -43,7 +43,7 @@ func getorigdst(fd uintptr) (socks.Addr, error) {
 	}
 
 	addr := make([]byte, 1+net.IPv4len+2)
-	addr[0] = socks.AtypIPv4
+	addr[0] = socks5.AtypIPv4
 	copy(addr[1:1+net.IPv4len], raw.Addr[:])
 	port := (*[2]byte)(unsafe.Pointer(&raw.Port)) // big-endian
 	addr[1+net.IPv4len], addr[1+net.IPv4len+1] = port[0], port[1]

proxy/redir/tcp_windows.go

@@ -4,9 +4,9 @@ import (
 	"errors"
 	"net"
 
-	"github.com/Dreamacro/go-shadowsocks2/socks"
+	"github.com/Dreamacro/clash/component/socks5"
 )
 
-func parserPacket(conn net.Conn) (socks.Addr, error) {
+func parserPacket(conn net.Conn) (socks5.Addr, error) {
 	return nil, errors.New("Windows not support yet")
 }

proxy/socks/tcp.go

@@ -1,57 +1,19 @@
 package socks
 
 import (
-	"io"
 	"net"
-	"strconv"
 
 	adapters "github.com/Dreamacro/clash/adapters/inbound"
+	"github.com/Dreamacro/clash/component/socks5"
 	C "github.com/Dreamacro/clash/constant"
 	"github.com/Dreamacro/clash/log"
 	"github.com/Dreamacro/clash/tunnel"
-
-	"github.com/Dreamacro/go-shadowsocks2/socks"
 )
 
 var (
 	tun = tunnel.Instance()
 )
 
-// Error represents a SOCKS error
-type Error byte
-
-func (err Error) Error() string {
-	return "SOCKS error: " + strconv.Itoa(int(err))
-}
-
-// SOCKS request commands as defined in RFC 1928 section 4.
-const (
-	CmdConnect      = 1
-	CmdBind         = 2
-	CmdUDPAssociate = 3
-)
-
-// SOCKS address types as defined in RFC 1928 section 5.
-const (
-	AtypIPv4       = 1
-	AtypDomainName = 3
-	AtypIPv6       = 4
-)
-
-const MaxAddrLen = 1 + 1 + 255 + 2
-
-// SOCKS errors as defined in RFC 1928 section 6.
-const (
-	ErrGeneralFailure       = Error(1)
-	ErrConnectionNotAllowed = Error(2)
-	ErrNetworkUnreachable   = Error(3)
-	ErrHostUnreachable      = Error(4)
-	ErrConnectionRefused    = Error(5)
-	ErrTTLExpired           = Error(6)
-	ErrCommandNotSupported  = Error(7)
-	ErrAddressNotSupported  = Error(8)
-)
-
 type SockListener struct {
 	net.Listener
 	address string
@@ -92,78 +54,15 @@ func (l *SockListener) Address() string {
 }
 
 func handleSocks(conn net.Conn) {
-	target, command, err := handshake(conn)
+	target, command, err := socks5.ServerHandshake(conn)
 	if err != nil {
 		conn.Close()
 		return
 	}
 	conn.(*net.TCPConn).SetKeepAlive(true)
-	if command == CmdUDPAssociate {
+	if command == socks5.CmdUDPAssociate {
 		tun.Add(adapters.NewSocket(target, conn, C.SOCKS, C.UDP))
 		return
 	}
 	tun.Add(adapters.NewSocket(target, conn, C.SOCKS, C.TCP))
 }
-
-// handshake fast-tracks SOCKS initialization to get target address to connect.
-func handshake(rw io.ReadWriter) (addr socks.Addr, command int, err error) {
-	// Read RFC 1928 for request and reply structure and sizes.
-	buf := make([]byte, MaxAddrLen)
-	// read VER, NMETHODS, METHODS
-	if _, err = io.ReadFull(rw, buf[:2]); err != nil {
-		return
-	}
-	nmethods := buf[1]
-	if _, err = io.ReadFull(rw, buf[:nmethods]); err != nil {
-		return
-	}
-	// write VER METHOD
-	if _, err = rw.Write([]byte{5, 0}); err != nil {
-		return
-	}
-	// read VER CMD RSV ATYP DST.ADDR DST.PORT
-	if _, err = io.ReadFull(rw, buf[:3]); err != nil {
-		return
-	}
-	if buf[1] != CmdConnect && buf[1] != CmdUDPAssociate {
-		err = ErrCommandNotSupported
-		return
-	}
-
-	command = int(buf[1])
-	addr, err = readAddr(rw, buf)
-	if err != nil {
-		return
-	}
-	// write VER REP RSV ATYP BND.ADDR BND.PORT
-	_, err = rw.Write([]byte{5, 0, 0, 1, 0, 0, 0, 0, 0, 0})
-	return
-}
-
-func readAddr(r io.Reader, b []byte) (socks.Addr, error) {
-	if len(b) < MaxAddrLen {
-		return nil, io.ErrShortBuffer
-	}
-	_, err := io.ReadFull(r, b[:1]) // read 1st byte for address type
-	if err != nil {
-		return nil, err
-	}
-
-	switch b[0] {
-	case AtypDomainName:
-		_, err = io.ReadFull(r, b[1:2]) // read 2nd byte for domain length
-		if err != nil {
-			return nil, err
-		}
-		_, err = io.ReadFull(r, b[2:2+b[1]+2])
-		return b[:1+1+b[1]+2], err
-	case AtypIPv4:
-		_, err = io.ReadFull(r, b[1:1+net.IPv4len+2])
-		return b[:1+net.IPv4len+2], err
-	case AtypIPv6:
-		_, err = io.ReadFull(r, b[1:1+net.IPv6len+2])
-		return b[:1+net.IPv6len+2], err
-	}
-
-	return nil, ErrAddressNotSupported
-}