Feature: socks5 udp associate

README.md

@@ -122,7 +122,7 @@ Proxy:
 # The types of cipher are consistent with go-shadowsocks2
 # support AEAD_AES_128_GCM AEAD_AES_192_GCM AEAD_AES_256_GCM AEAD_CHACHA20_POLY1305 AES-128-CTR AES-192-CTR AES-256-CTR AES-128-CFB AES-192-CFB AES-256-CFB CHACHA20-IETF XCHACHA20
 # In addition to what go-shadowsocks2 supports, it also supports chacha20 rc4-md5 xchacha20-ietf-poly1305
-- { name: "ss1", type: ss, server: server, port: 443, cipher: AEAD_CHACHA20_POLY1305, password: "password" }
+- { name: "ss1", type: ss, server: server, port: 443, cipher: AEAD_CHACHA20_POLY1305, password: "password", udp: true }
 
 # old obfs configuration remove after prerelease
 - name: "ss2"
@@ -226,5 +226,5 @@ https://clash.gitbook.io/
 
 - [x] Complementing the necessary rule operators
 - [x] Redir proxy
-- [ ] UDP support
+- [ ] UDP support (vmess, outbound socks5)
 - [ ] Connection manager

adapters/inbound/http.go

@@ -10,26 +10,16 @@ import (
 
 // HTTPAdapter is a adapter for HTTP connection
 type HTTPAdapter struct {
+	net.Conn
 	metadata *C.Metadata
-	conn     net.Conn
 	R        *http.Request
 }
 
-// Close HTTP connection
-func (h *HTTPAdapter) Close() {
-	h.conn.Close()
-}
-
 // Metadata return destination metadata
 func (h *HTTPAdapter) Metadata() *C.Metadata {
 	return h.metadata
 }
 
-// Conn return raw net.Conn of HTTP
-func (h *HTTPAdapter) Conn() net.Conn {
-	return h.conn
-}
-
 // NewHTTP is HTTPAdapter generator
 func NewHTTP(request *http.Request, conn net.Conn) *HTTPAdapter {
 	metadata := parseHTTPAddr(request)
@@ -37,7 +27,7 @@ func NewHTTP(request *http.Request, conn net.Conn) *HTTPAdapter {
 	return &HTTPAdapter{
 		metadata: metadata,
 		R:        request,
-		conn:     conn,
+		Conn:     conn,
 	}
 }
 

adapters/inbound/https.go

@@ -11,6 +11,6 @@ func NewHTTPS(request *http.Request, conn net.Conn) *SocketAdapter {
 	metadata.SourceIP = parseSourceIP(conn)
 	return &SocketAdapter{
 		metadata: metadata,
-		conn:     conn,
+		Conn:     conn,
 	}
 }

adapters/inbound/socket.go

@@ -9,33 +9,24 @@ import (
 
 // SocketAdapter is a adapter for socks and redir connection
 type SocketAdapter struct {
-	conn     net.Conn
+	net.Conn
 	metadata *C.Metadata
 }
 
-// Close socks and redir connection
-func (s *SocketAdapter) Close() {
-	s.conn.Close()
-}
-
 // Metadata return destination metadata
 func (s *SocketAdapter) Metadata() *C.Metadata {
 	return s.metadata
 }
 
-// Conn return raw net.Conn
-func (s *SocketAdapter) Conn() net.Conn {
-	return s.conn
-}
-
 // NewSocket is SocketAdapter generator
-func NewSocket(target socks.Addr, conn net.Conn, source C.SourceType) *SocketAdapter {
+func NewSocket(target socks.Addr, conn net.Conn, source C.SourceType, netType C.NetWork) *SocketAdapter {
 	metadata := parseSocksAddr(target)
+	metadata.NetWork = netType
 	metadata.Source = source
 	metadata.SourceIP = parseSourceIP(conn)
 
 	return &SocketAdapter{
-		conn:     conn,
+		Conn:     conn,
 		metadata: metadata,
 	}
 }

adapters/inbound/util.go

@@ -11,7 +11,6 @@ import (
 
 func parseSocksAddr(target socks.Addr) *C.Metadata {
 	metadata := &C.Metadata{
-		NetWork:  C.TCP,
 		AddrType: int(target[0]),
 	}
 

adapters/outbound/base.go

@@ -2,6 +2,7 @@ package adapters
 
 import (
 	"encoding/json"
+	"errors"
 	"net"
 	"net/http"
 	"time"
@@ -13,6 +14,7 @@ import (
 type Base struct {
 	name string
 	tp   C.AdapterType
+	udp  bool
 }
 
 func (b *Base) Name() string {
@@ -23,6 +25,14 @@ func (b *Base) Type() C.AdapterType {
 	return b.tp
 }
 
+func (b *Base) DialUDP(metadata *C.Metadata) (net.PacketConn, net.Addr, error) {
+	return nil, nil, errors.New("no support")
+}
+
+func (b *Base) SupportUDP() bool {
+	return b.udp
+}
+
 func (b *Base) Destroy() {}
 
 func (b *Base) MarshalJSON() ([]byte, error) {

adapters/outbound/direct.go

@@ -24,11 +24,22 @@ func (d *Direct) Dial(metadata *C.Metadata) (net.Conn, error) {
 	return c, nil
 }
 
+func (d *Direct) DialUDP(metadata *C.Metadata) (net.PacketConn, net.Addr, error) {
+	pc, err := net.ListenPacket("udp", "")
+	if err != nil {
+		return nil, nil, err
+	}
+
+	addr, _ := net.ResolveUDPAddr("udp", net.JoinHostPort(metadata.String(), metadata.Port))
+	return pc, addr, nil
+}
+
 func NewDirect() *Direct {
 	return &Direct{
 		Base: &Base{
 			name: "DIRECT",
 			tp:   C.Direct,
+			udp:  true,
 		},
 	}
 }

adapters/outbound/fallback.go

@@ -35,6 +35,16 @@ func (f *Fallback) Dial(metadata *C.Metadata) (net.Conn, error) {
 	return proxy.Dial(metadata)
 }
 
+func (f *Fallback) DialUDP(metadata *C.Metadata) (net.PacketConn, net.Addr, error) {
+	proxy := f.findAliveProxy()
+	return proxy.DialUDP(metadata)
+}
+
+func (f *Fallback) SupportUDP() bool {
+	proxy := f.findAliveProxy()
+	return proxy.SupportUDP()
+}
+
 func (f *Fallback) MarshalJSON() ([]byte, error) {
 	var all []string
 	for _, proxy := range f.proxies {

adapters/outbound/loadbalance.go

@@ -67,6 +67,24 @@ func (lb *LoadBalance) Dial(metadata *C.Metadata) (net.Conn, error) {
 	return lb.proxies[0].Dial(metadata)
 }
 
+func (lb *LoadBalance) DialUDP(metadata *C.Metadata) (net.PacketConn, net.Addr, error) {
+	key := uint64(murmur3.Sum32([]byte(getKey(metadata))))
+	buckets := int32(len(lb.proxies))
+	for i := 0; i < lb.maxRetry; i, key = i+1, key+1 {
+		idx := jumpHash(key, buckets)
+		proxy := lb.proxies[idx]
+		if proxy.Alive() {
+			return proxy.DialUDP(metadata)
+		}
+	}
+
+	return lb.proxies[0].DialUDP(metadata)
+}
+
+func (lb *LoadBalance) SupportUDP() bool {
+	return true
+}
+
 func (lb *LoadBalance) Destroy() {
 	lb.done <- struct{}{}
 }

adapters/outbound/selector.go

@@ -24,6 +24,14 @@ func (s *Selector) Dial(metadata *C.Metadata) (net.Conn, error) {
 	return s.selected.Dial(metadata)
 }
 
+func (s *Selector) DialUDP(metadata *C.Metadata) (net.PacketConn, net.Addr, error) {
+	return s.selected.DialUDP(metadata)
+}
+
+func (s *Selector) SupportUDP() bool {
+	return s.selected.SupportUDP()
+}
+
 func (s *Selector) MarshalJSON() ([]byte, error) {
 	var all []string
 	for k := range s.proxies {

adapters/outbound/shadowsocks.go

@@ -8,6 +8,7 @@ import (
 	"net"
 	"strconv"
 
+	"github.com/Dreamacro/clash/common/pool"
 	"github.com/Dreamacro/clash/common/structure"
 	obfs "github.com/Dreamacro/clash/component/simple-obfs"
 	v2rayObfs "github.com/Dreamacro/clash/component/v2ray-plugin"
@@ -34,6 +35,7 @@ type ShadowSocksOption struct {
 	Port       int                    `proxy:"port"`
 	Password   string                 `proxy:"password"`
 	Cipher     string                 `proxy:"cipher"`
+	UDP        bool                   `proxy:"udp,omitempty"`
 	Plugin     string                 `proxy:"plugin,omitempty"`
 	PluginOpts map[string]interface{} `proxy:"plugin-opts,omitempty"`
 
@@ -80,6 +82,19 @@ func (ss *ShadowSocks) Dial(metadata *C.Metadata) (net.Conn, error) {
 	return c, err
 }
 
+func (ss *ShadowSocks) DialUDP(metadata *C.Metadata) (net.PacketConn, net.Addr, error) {
+	pc, err := net.ListenPacket("udp", "")
+	if err != nil {
+		return nil, nil, err
+	}
+
+	addr, _ := net.ResolveUDPAddr("udp", ss.server)
+	remoteAddr, _ := net.ResolveUDPAddr("udp", net.JoinHostPort(metadata.String(), metadata.Port))
+
+	pc = ss.cipher.PacketConn(pc)
+	return &ssUDPConn{PacketConn: pc, rAddr: remoteAddr}, addr, nil
+}
+
 func (ss *ShadowSocks) MarshalJSON() ([]byte, error) {
 	return json.Marshal(map[string]string{
 		"type": ss.Type().String(),
@@ -144,6 +159,7 @@ func NewShadowSocks(option ShadowSocksOption) (*ShadowSocks, error) {
 		Base: &Base{
 			name: option.Name,
 			tp:   C.Shadowsocks,
+			udp:  option.UDP,
 		},
 		server: server,
 		cipher: ciph,
@@ -173,3 +189,24 @@ func serializesSocksAddr(metadata *C.Metadata) []byte {
 	}
 	return bytes.Join(buf, nil)
 }
+
+type ssUDPConn struct {
+	net.PacketConn
+	rAddr net.Addr
+}
+
+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())
+	copy(buf[len(rAddr):], b)
+	copy(buf, rAddr)
+	return uc.PacketConn.WriteTo(buf[:len(rAddr)+len(b)], addr)
+}
+
+func (uc *ssUDPConn) ReadFrom(b []byte) (int, net.Addr, error) {
+	n, a, e := uc.PacketConn.ReadFrom(b)
+	addr := socks.SplitAddr(b[:n])
+	copy(b, b[len(addr):])
+	return n - len(addr), a, e
+}

adapters/outbound/socks5.go

@@ -31,6 +31,7 @@ type Socks5Option struct {
 	UserName       string `proxy:"username,omitempty"`
 	Password       string `proxy:"password,omitempty"`
 	TLS            bool   `proxy:"tls,omitempty"`
+	UDP            bool   `proxy:"udp,omitempty"`
 	SkipCertVerify bool   `proxy:"skip-cert-verify,omitempty"`
 }
 
@@ -126,6 +127,7 @@ func NewSocks5(option Socks5Option) *Socks5 {
 		Base: &Base{
 			name: option.Name,
 			tp:   C.Socks5,
+			udp:  option.UDP,
 		},
 		addr:           net.JoinHostPort(option.Server, strconv.Itoa(option.Port)),
 		user:           option.UserName,

adapters/outbound/urltest.go

@@ -43,6 +43,14 @@ func (u *URLTest) Dial(metadata *C.Metadata) (net.Conn, error) {
 	return a, err
 }
 
+func (u *URLTest) DialUDP(metadata *C.Metadata) (net.PacketConn, net.Addr, error) {
+	return u.fast.DialUDP(metadata)
+}
+
+func (u *URLTest) SupportUDP() bool {
+	return u.fast.SupportUDP()
+}
+
 func (u *URLTest) MarshalJSON() ([]byte, error) {
 	var all []string
 	for _, proxy := range u.proxies {

common/pool/pool.go

@@ -0,0 +1,15 @@
+package pool
+
+import (
+	"sync"
+)
+
+const (
+	// io.Copy default buffer size is 32 KiB
+	// but the maximum packet size of vmess/shadowsocks is about 16 KiB
+	// so define a buffer of 20 KiB to reduce the memory of each TCP relay
+	bufferSize = 20 * 1024
+)
+
+// BufPool provide buffer for relay
+var BufPool = sync.Pool{New: func() interface{} { return make([]byte, bufferSize) }}

component/simple-obfs/http.go

@@ -8,6 +8,8 @@ import (
 	"math/rand"
 	"net"
 	"net/http"
+
+	"github.com/Dreamacro/clash/common/pool"
 )
 
 // HTTPObfs is shadowsocks http simple-obfs implementation
@@ -32,15 +34,15 @@ func (ho *HTTPObfs) Read(b []byte) (int, error) {
 	}
 
 	if ho.firstResponse {
-		buf := bufPool.Get().([]byte)
+		buf := pool.BufPool.Get().([]byte)
 		n, err := ho.Conn.Read(buf)
 		if err != nil {
-			bufPool.Put(buf[:cap(buf)])
+			pool.BufPool.Put(buf[:cap(buf)])
 			return 0, err
 		}
 		idx := bytes.Index(buf[:n], []byte("\r\n\r\n"))
 		if idx == -1 {
-			bufPool.Put(buf[:cap(buf)])
+			pool.BufPool.Put(buf[:cap(buf)])
 			return 0, io.EOF
 		}
 		ho.firstResponse = false
@@ -50,7 +52,7 @@ func (ho *HTTPObfs) Read(b []byte) (int, error) {
 			ho.buf = buf[:idx+4+length]
 			ho.offset = idx + 4 + n
 		} else {
-			bufPool.Put(buf[:cap(buf)])
+			pool.BufPool.Put(buf[:cap(buf)])
 		}
 		return n, nil
 	}

component/simple-obfs/tls.go

@@ -6,8 +6,9 @@ import (
 	"io"
 	"math/rand"
 	"net"
-	"sync"
 	"time"
+
+	"github.com/Dreamacro/clash/common/pool"
 )
 
 func init() {
@@ -18,8 +19,6 @@ const (
 	chunkSize = 1 << 14 // 2 ** 14 == 16 * 1024
 )
 
-var bufPool = sync.Pool{New: func() interface{} { return make([]byte, 2048) }}
-
 // TLSObfs is shadowsocks tls simple-obfs implementation
 type TLSObfs struct {
 	net.Conn
@@ -30,12 +29,12 @@ type TLSObfs struct {
 }
 
 func (to *TLSObfs) read(b []byte, discardN int) (int, error) {
-	buf := bufPool.Get().([]byte)
+	buf := pool.BufPool.Get().([]byte)
 	_, err := io.ReadFull(to.Conn, buf[:discardN])
 	if err != nil {
 		return 0, err
 	}
-	bufPool.Put(buf[:cap(buf)])
+	pool.BufPool.Put(buf[:cap(buf)])
 
 	sizeBuf := make([]byte, 2)
 	_, err = io.ReadFull(to.Conn, sizeBuf)
@@ -103,7 +102,7 @@ func (to *TLSObfs) write(b []byte) (int, error) {
 		return len(b), err
 	}
 
-	size := bufPool.Get().([]byte)
+	size := pool.BufPool.Get().([]byte)
 	binary.BigEndian.PutUint16(size[:2], uint16(len(b)))
 
 	buf := &bytes.Buffer{}
@@ -111,7 +110,7 @@ func (to *TLSObfs) write(b []byte) (int, error) {
 	buf.Write(size[:2])
 	buf.Write(b)
 	_, err := to.Conn.Write(buf.Bytes())
-	bufPool.Put(size[:cap(size)])
+	pool.BufPool.Put(size[:cap(size)])
 	return len(b), err
 }
 

component/vmess/aead.go

@@ -5,6 +5,8 @@ import (
 	"encoding/binary"
 	"errors"
 	"io"
+
+	"github.com/Dreamacro/clash/common/pool"
 )
 
 type aeadWriter struct {
@@ -20,8 +22,8 @@ func newAEADWriter(w io.Writer, aead cipher.AEAD, iv []byte) *aeadWriter {
 }
 
 func (w *aeadWriter) Write(b []byte) (n int, err error) {
-	buf := bufPool.Get().([]byte)
-	defer bufPool.Put(buf[:cap(buf)])
+	buf := pool.BufPool.Get().([]byte)
+	defer pool.BufPool.Put(buf[:cap(buf)])
 	length := len(b)
 	for {
 		if length == 0 {
@@ -71,7 +73,7 @@ func (r *aeadReader) Read(b []byte) (int, error) {
 		n := copy(b, r.buf[r.offset:])
 		r.offset += n
 		if r.offset == len(r.buf) {
-			bufPool.Put(r.buf[:cap(r.buf)])
+			pool.BufPool.Put(r.buf[:cap(r.buf)])
 			r.buf = nil
 		}
 		return n, nil
@@ -87,10 +89,10 @@ func (r *aeadReader) Read(b []byte) (int, error) {
 		return 0, errors.New("Buffer is larger than standard")
 	}
 
-	buf := bufPool.Get().([]byte)
+	buf := pool.BufPool.Get().([]byte)
 	_, err = io.ReadFull(r.Reader, buf[:size])
 	if err != nil {
-		bufPool.Put(buf[:cap(buf)])
+		pool.BufPool.Put(buf[:cap(buf)])
 		return 0, err
 	}
 
@@ -105,7 +107,7 @@ func (r *aeadReader) Read(b []byte) (int, error) {
 	realLen := size - r.Overhead()
 	n := copy(b, buf[:realLen])
 	if len(b) >= realLen {
-		bufPool.Put(buf[:cap(buf)])
+		pool.BufPool.Put(buf[:cap(buf)])
 		return n, nil
 	}
 

component/vmess/chunk.go

@@ -4,7 +4,8 @@ import (
 	"encoding/binary"
 	"errors"
 	"io"
-	"sync"
+
+	"github.com/Dreamacro/clash/common/pool"
 )
 
 const (
@@ -13,8 +14,6 @@ const (
 	maxSize   = 17 * 1024 // 2 + chunkSize + aead.Overhead()
 )
 
-var bufPool = sync.Pool{New: func() interface{} { return make([]byte, maxSize) }}
-
 type chunkReader struct {
 	io.Reader
 	buf     []byte
@@ -35,7 +34,7 @@ func (cr *chunkReader) Read(b []byte) (int, error) {
 		n := copy(b, cr.buf[cr.offset:])
 		cr.offset += n
 		if cr.offset == len(cr.buf) {
-			bufPool.Put(cr.buf[:cap(cr.buf)])
+			pool.BufPool.Put(cr.buf[:cap(cr.buf)])
 			cr.buf = nil
 		}
 		return n, nil
@@ -60,10 +59,10 @@ func (cr *chunkReader) Read(b []byte) (int, error) {
 		return size, nil
 	}
 
-	buf := bufPool.Get().([]byte)
+	buf := pool.BufPool.Get().([]byte)
 	_, err = io.ReadFull(cr.Reader, buf[:size])
 	if err != nil {
-		bufPool.Put(buf[:cap(buf)])
+		pool.BufPool.Put(buf[:cap(buf)])
 		return 0, err
 	}
 	n := copy(b, cr.buf[:])
@@ -77,8 +76,8 @@ type chunkWriter struct {
 }
 
 func (cw *chunkWriter) Write(b []byte) (n int, err error) {
-	buf := bufPool.Get().([]byte)
-	defer bufPool.Put(buf[:cap(buf)])
+	buf := pool.BufPool.Get().([]byte)
+	defer pool.BufPool.Put(buf[:cap(buf)])
 	length := len(b)
 	for {
 		if length == 0 {

constant/adapters.go

@@ -20,14 +20,16 @@ const (
 )
 
 type ServerAdapter interface {
+	net.Conn
 	Metadata() *Metadata
-	Close()
 }
 
 type ProxyAdapter interface {
 	Name() string
 	Type() AdapterType
 	Dial(metadata *Metadata) (net.Conn, error)
+	DialUDP(metadata *Metadata) (net.PacketConn, net.Addr, error)
+	SupportUDP() bool
 	Destroy()
 	MarshalJSON() ([]byte, error)
 }

go.mod

@@ -1,7 +1,7 @@
 module github.com/Dreamacro/clash
 
 require (
-	github.com/Dreamacro/go-shadowsocks2 v0.1.3-0.20190202135136-da4602d8f112
+	github.com/Dreamacro/go-shadowsocks2 v0.1.3-0.20190406142755-9128a199439f
 	github.com/eapache/queue v1.1.0 // indirect
 	github.com/go-chi/chi v4.0.1+incompatible
 	github.com/go-chi/cors v1.0.0

go.sum

@@ -1,5 +1,5 @@
-github.com/Dreamacro/go-shadowsocks2 v0.1.3-0.20190202135136-da4602d8f112 h1:1axYxE0ZLJy40+ulq46XQt7MaJDJr4iGer1NQz7jmKw=
-github.com/Dreamacro/go-shadowsocks2 v0.1.3-0.20190202135136-da4602d8f112/go.mod h1:giIuN+TuUudTxHc1jjTOyyQYiJ3VXp1pWOHdJbSCAPo=
+github.com/Dreamacro/go-shadowsocks2 v0.1.3-0.20190406142755-9128a199439f h1:nlImrmI6I2AVjJ2AvE3w3f7fi8rhLQAhZO1Gs31+/nE=
+github.com/Dreamacro/go-shadowsocks2 v0.1.3-0.20190406142755-9128a199439f/go.mod h1:giIuN+TuUudTxHc1jjTOyyQYiJ3VXp1pWOHdJbSCAPo=
 github.com/aead/chacha20 v0.0.0-20180709150244-8b13a72661da h1:KjTM2ks9d14ZYCvmHS9iAKVt9AyzRSqNU1qabPih5BY=
 github.com/aead/chacha20 v0.0.0-20180709150244-8b13a72661da/go.mod h1:eHEWzANqSiWQsof+nXEI9bUVUyV6F53Fp89EuCh2EAA=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=

proxy/redir/tcp.go

@@ -59,5 +59,5 @@ func handleRedir(conn net.Conn) {
 		return
 	}
 	conn.(*net.TCPConn).SetKeepAlive(true)
-	tun.Add(adapters.NewSocket(target, conn, C.REDIR))
+	tun.Add(adapters.NewSocket(target, conn, C.REDIR, C.TCP))
 }

proxy/socks/tcp.go

@@ -1,9 +1,11 @@
 package socks
 
 import (
+	"io"
 	"net"
+	"strconv"
 
-	"github.com/Dreamacro/clash/adapters/inbound"
+	adapters "github.com/Dreamacro/clash/adapters/inbound"
 	C "github.com/Dreamacro/clash/constant"
 	"github.com/Dreamacro/clash/log"
 	"github.com/Dreamacro/clash/tunnel"
@@ -15,6 +17,41 @@ 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
@@ -55,11 +92,78 @@ func (l *SockListener) Address() string {
 }
 
 func handleSocks(conn net.Conn) {
-	target, err := socks.Handshake(conn)
+	target, command, err := handshake(conn)
 	if err != nil {
 		conn.Close()
 		return
 	}
 	conn.(*net.TCPConn).SetKeepAlive(true)
-	tun.Add(adapters.NewSocket(target, conn, C.SOCKS))
+	if command == 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
 }

tunnel/connection.go

@@ -6,21 +6,12 @@ import (
 	"net"
 	"net/http"
 	"strings"
-	"sync"
 	"time"
 
 	adapters "github.com/Dreamacro/clash/adapters/inbound"
+	"github.com/Dreamacro/clash/common/pool"
 )
 
-const (
-	// io.Copy default buffer size is 32 KiB
-	// but the maximum packet size of vmess/shadowsocks is about 16 KiB
-	// so define a buffer of 20 KiB to reduce the memory of each TCP relay
-	bufferSize = 20 * 1024
-)
-
-var bufPool = sync.Pool{New: func() interface{} { return make([]byte, bufferSize) }}
-
 func (t *Tunnel) handleHTTP(request *adapters.HTTPAdapter, outbound net.Conn) {
 	conn := newTrafficTrack(outbound, t.traffic)
 	req := request.R
@@ -50,7 +41,7 @@ func (t *Tunnel) handleHTTP(request *adapters.HTTPAdapter, outbound net.Conn) {
 		} else {
 			resp.Close = true
 		}
-		err = resp.Write(request.Conn())
+		err = resp.Write(request)
 		if err != nil || resp.Close {
 			break
 		}
@@ -59,7 +50,7 @@ func (t *Tunnel) handleHTTP(request *adapters.HTTPAdapter, outbound net.Conn) {
 			break
 		}
 
-		req, err = http.ReadRequest(bufio.NewReader(request.Conn()))
+		req, err = http.ReadRequest(bufio.NewReader(request))
 		if err != nil {
 			break
 		}
@@ -72,9 +63,52 @@ func (t *Tunnel) handleHTTP(request *adapters.HTTPAdapter, outbound net.Conn) {
 	}
 }
 
-func (t *Tunnel) handleSOCKS(request *adapters.SocketAdapter, outbound net.Conn) {
+func (t *Tunnel) handleSocket(request *adapters.SocketAdapter, outbound net.Conn) {
 	conn := newTrafficTrack(outbound, t.traffic)
-	relay(request.Conn(), conn)
+	relay(request, conn)
+}
+
+func (t *Tunnel) handleUDPOverTCP(conn net.Conn, pc net.PacketConn, addr net.Addr) error {
+	ch := make(chan error, 1)
+
+	go func() {
+		buf := pool.BufPool.Get().([]byte)
+		defer pool.BufPool.Put(buf)
+		for {
+			n, err := conn.Read(buf)
+			if err != nil {
+				ch <- err
+				return
+			}
+			pc.SetReadDeadline(time.Now().Add(120 * time.Second))
+			if _, err = pc.WriteTo(buf[:n], addr); err != nil {
+				ch <- err
+				return
+			}
+			t.traffic.Up() <- int64(n)
+			ch <- nil
+		}
+	}()
+
+	buf := pool.BufPool.Get().([]byte)
+	defer pool.BufPool.Put(buf)
+
+	for {
+		pc.SetReadDeadline(time.Now().Add(120 * time.Second))
+		n, _, err := pc.ReadFrom(buf)
+		if err != nil {
+			break
+		}
+
+		if _, err := conn.Write(buf[:n]); err != nil {
+			break
+		}
+
+		t.traffic.Down() <- int64(n)
+	}
+
+	<-ch
+	return nil
 }
 
 // relay copies between left and right bidirectionally.
@@ -82,16 +116,16 @@ func relay(leftConn, rightConn net.Conn) {
 	ch := make(chan error)
 
 	go func() {
-		buf := bufPool.Get().([]byte)
+		buf := pool.BufPool.Get().([]byte)
 		_, err := io.CopyBuffer(leftConn, rightConn, buf)
-		bufPool.Put(buf[:cap(buf)])
+		pool.BufPool.Put(buf[:cap(buf)])
 		leftConn.SetReadDeadline(time.Now())
 		ch <- err
 	}()
 
-	buf := bufPool.Get().([]byte)
+	buf := pool.BufPool.Get().([]byte)
 	io.CopyBuffer(rightConn, leftConn, buf)
-	bufPool.Put(buf[:cap(buf)])
+	pool.BufPool.Put(buf[:cap(buf)])
 	rightConn.SetReadDeadline(time.Now())
 	<-ch
 }

tunnel/tunnel.go

@@ -19,7 +19,7 @@ var (
 	once   sync.Once
 )
 
-// Tunnel handle proxy socket and HTTP/SOCKS socket
+// Tunnel handle relay inbound proxy and outbound proxy
 type Tunnel struct {
 	queue      *channels.InfiniteChannel
 	rules      []C.Rule
@@ -143,6 +143,12 @@ func (t *Tunnel) handleConn(localConn C.ServerAdapter) {
 		}
 	}
 
+	if metadata.NetWork == C.UDP {
+		pc, addr, _ := proxy.DialUDP(metadata)
+		t.handleUDPOverTCP(localConn, pc, addr)
+		return
+	}
+
 	remoConn, err := proxy.Dial(metadata)
 	if err != nil {
 		log.Warnln("Proxy[%s] connect [%s --> %s] error: %s", proxy.Name(), metadata.SourceIP.String(), metadata.String(), err.Error())
@@ -154,7 +160,7 @@ func (t *Tunnel) handleConn(localConn C.ServerAdapter) {
 	case *InboundAdapter.HTTPAdapter:
 		t.handleHTTP(adapter, remoConn)
 	case *InboundAdapter.SocketAdapter:
-		t.handleSOCKS(adapter, remoConn)
+		t.handleSocket(adapter, remoConn)
 	}
 }
 
@@ -177,10 +183,17 @@ func (t *Tunnel) match(metadata *C.Metadata) (C.Proxy, error) {
 		}
 
 		if rule.IsMatch(metadata) {
-			if a, ok := t.proxies[rule.Adapter()]; ok {
-				log.Infoln("%s --> %v match %s using %s", metadata.SourceIP.String(), metadata.String(), rule.RuleType().String(), rule.Adapter())
-				return a, nil
+			adapter, ok := t.proxies[rule.Adapter()]
+			if !ok {
+				continue
 			}
+
+			if metadata.NetWork == C.UDP && !adapter.SupportUDP() {
+				continue
+			}
+
+			log.Infoln("%s --> %v match %s using %s", metadata.SourceIP.String(), metadata.String(), rule.RuleType().String(), rule.Adapter())
+			return adapter, nil
 		}
 	}
 	log.Infoln("%s --> %v doesn't match any rule using DIRECT", metadata.SourceIP.String(), metadata.String())