separate ssu from ss

cmd/gost/config.go

@@ -1,227 +0,0 @@
-package main
-
-import (
-	"io"
-	"os"
-	"strings"
-
-	"github.com/go-gost/gost/pkg/bypass"
-	"github.com/go-gost/gost/pkg/chain"
-	"github.com/go-gost/gost/pkg/config"
-	"github.com/go-gost/gost/pkg/connector"
-	"github.com/go-gost/gost/pkg/dialer"
-	"github.com/go-gost/gost/pkg/handler"
-	"github.com/go-gost/gost/pkg/listener"
-	"github.com/go-gost/gost/pkg/logger"
-	"github.com/go-gost/gost/pkg/metadata"
-	"github.com/go-gost/gost/pkg/registry"
-	"github.com/go-gost/gost/pkg/service"
-)
-
-var (
-	chains   = make(map[string]*chain.Chain)
-	bypasses = make(map[string]bypass.Bypass)
-)
-
-func buildService(cfg *config.Config) (services []*service.Service) {
-	if cfg == nil || len(cfg.Services) == 0 {
-		return
-	}
-
-	for _, bypassCfg := range cfg.Bypasses {
-		bypasses[bypassCfg.Name] = bypassFromConfig(bypassCfg)
-	}
-
-	for _, chainCfg := range cfg.Chains {
-		chains[chainCfg.Name] = chainFromConfig(chainCfg)
-	}
-
-	for _, svc := range cfg.Services {
-		serviceLogger := log.WithFields(map[string]interface{}{
-			"service": svc.Name,
-		})
-
-		listenerLogger := serviceLogger.WithFields(map[string]interface{}{
-			"kind": "listener",
-			"type": svc.Listener.Type,
-		})
-		ln := registry.GetListener(svc.Listener.Type)(
-			listener.AddrOption(svc.Addr),
-			listener.LoggerOption(listenerLogger),
-		)
-
-		cln, chainable := ln.(listener.Chainable)
-		if chainable {
-			cln.Chain(chains[svc.Chain])
-		}
-
-		if err := ln.Init(metadata.MapMetadata(svc.Listener.Metadata)); err != nil {
-			listenerLogger.Fatal("init: ", err)
-		}
-
-		handlerLogger := serviceLogger.WithFields(map[string]interface{}{
-			"kind": "handler",
-			"type": svc.Handler.Type,
-		})
-
-		h := registry.GetHandler(svc.Handler.Type)(
-			handler.ChainOption(chains[svc.Chain]),
-			handler.BypassOption(bypasses[svc.Bypass]),
-			handler.LoggerOption(handlerLogger),
-		)
-
-		if forwarder, ok := h.(handler.Forwarder); ok {
-			chain := chains[svc.Chain]
-			if chainable {
-				chain = nil
-			}
-			forwarder.Forward(forwarderFromConfig(svc.Forwarder), chain)
-		}
-
-		if err := h.Init(metadata.MapMetadata(svc.Handler.Metadata)); err != nil {
-			handlerLogger.Fatal("init: ", err)
-		}
-
-		s := (&service.Service{}).
-			WithListener(ln).
-			WithHandler(h).
-			WithLogger(serviceLogger)
-		services = append(services, s)
-
-		serviceLogger.Info("listening on: ", s.Addr())
-	}
-
-	return
-}
-
-func chainFromConfig(cfg *config.ChainConfig) *chain.Chain {
-	if cfg == nil {
-		return nil
-	}
-
-	c := &chain.Chain{}
-
-	selector := selectorFromConfig(cfg.Selector)
-	for _, hop := range cfg.Hops {
-		group := &chain.NodeGroup{}
-		for _, v := range hop.Nodes {
-
-			connectorLogger := log.WithFields(map[string]interface{}{
-				"kind": "connector",
-				"type": v.Connector.Type,
-				"hop":  hop.Name,
-				"node": v.Name,
-			})
-			cr := registry.GetConnector(v.Connector.Type)(
-				connector.LoggerOption(connectorLogger),
-			)
-			if err := cr.Init(metadata.MapMetadata(v.Connector.Metadata)); err != nil {
-				connectorLogger.Fatal("init: ", err)
-			}
-
-			dialerLogger := log.WithFields(map[string]interface{}{
-				"kind": "dialer",
-				"type": v.Dialer.Type,
-				"hop":  hop.Name,
-				"node": v.Name,
-			})
-			d := registry.GetDialer(v.Dialer.Type)(
-				dialer.LoggerOption(dialerLogger),
-			)
-			if err := d.Init(metadata.MapMetadata(v.Dialer.Metadata)); err != nil {
-				dialerLogger.Fatal("init: ", err)
-			}
-
-			tr := (&chain.Transport{}).
-				WithConnector(cr).
-				WithDialer(d)
-
-			node := chain.NewNode(v.Name, v.Addr).
-				WithTransport(tr).
-				WithBypass(bypasses[v.Bypass])
-			group.AddNode(node)
-		}
-
-		sel := selector
-		if s := selectorFromConfig(hop.Selector); s != nil {
-			sel = s
-		}
-		group.WithSelector(sel)
-		c.AddNodeGroup(group)
-	}
-
-	return c
-}
-
-func logFromConfig(cfg *config.LogConfig) logger.Logger {
-	if cfg == nil {
-		cfg = &config.LogConfig{}
-	}
-	opts := []logger.LoggerOption{
-		logger.FormatLoggerOption(logger.LogFormat(cfg.Format)),
-		logger.LevelLoggerOption(logger.LogLevel(cfg.Level)),
-	}
-
-	var out io.Writer = os.Stderr
-	switch cfg.Output {
-	case "stdout", "":
-		out = os.Stdout
-	case "stderr":
-		out = os.Stderr
-	default:
-		f, err := os.OpenFile(cfg.Output, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
-		if err != nil {
-			log.Warnf("log", err)
-		} else {
-			out = f
-		}
-	}
-	opts = append(opts, logger.OutputLoggerOption(out))
-
-	return logger.NewLogger(opts...)
-}
-
-func selectorFromConfig(cfg *config.SelectorConfig) chain.Selector {
-	if cfg == nil {
-		return nil
-	}
-
-	var strategy chain.Strategy
-	switch cfg.Strategy {
-	case "round":
-		strategy = chain.RoundRobinStrategy()
-	case "random":
-		strategy = chain.RandomStrategy()
-	case "fifo":
-		strategy = chain.FIFOStrategy()
-	default:
-		strategy = chain.RoundRobinStrategy()
-	}
-
-	return chain.NewSelector(
-		strategy,
-		chain.InvalidFilter(),
-		chain.FailFilter(cfg.MaxFails, cfg.FailTimeout),
-	)
-}
-
-func bypassFromConfig(cfg *config.BypassConfig) bypass.Bypass {
-	if cfg == nil {
-		return nil
-	}
-	return bypass.NewBypassPatterns(cfg.Reverse, cfg.Matchers...)
-}
-
-func forwarderFromConfig(cfg *config.ForwarderConfig) *chain.NodeGroup {
-	if cfg == nil || len(cfg.Targets) == 0 {
-		return nil
-	}
-
-	group := &chain.NodeGroup{}
-	for _, target := range cfg.Targets {
-		if v := strings.TrimSpace(target); v != "" {
-			group.AddNode(chain.NewNode(target, target))
-		}
-	}
-	return group.WithSelector(selectorFromConfig(cfg.Selector))
-}

cmd/gost/register.go

@@ -6,6 +6,7 @@ import (
 	_ "github.com/go-gost/gost/pkg/connector/socks/v4"
 	_ "github.com/go-gost/gost/pkg/connector/socks/v5"
 	_ "github.com/go-gost/gost/pkg/connector/ss"
+	_ "github.com/go-gost/gost/pkg/connector/ss/udp"
 
 	// Register dialers
 	_ "github.com/go-gost/gost/pkg/dialer/tcp"
@@ -18,6 +19,7 @@ import (
 	_ "github.com/go-gost/gost/pkg/handler/socks/v4"
 	_ "github.com/go-gost/gost/pkg/handler/socks/v5"
 	_ "github.com/go-gost/gost/pkg/handler/ss"
+	_ "github.com/go-gost/gost/pkg/handler/ss/udp"
 
 	// Register listeners
 	_ "github.com/go-gost/gost/pkg/listener/ftcp"

pkg/connector/ss/connector.go

@@ -2,14 +2,12 @@ package ss
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"net"
 	"time"
 
 	"github.com/go-gost/gosocks5"
 	"github.com/go-gost/gost/pkg/common/bufpool"
-	"github.com/go-gost/gost/pkg/common/util/socks"
 	"github.com/go-gost/gost/pkg/common/util/ss"
 	"github.com/go-gost/gost/pkg/connector"
 	"github.com/go-gost/gost/pkg/logger"
@@ -57,8 +55,6 @@ func (c *ssConnector) Connect(ctx context.Context, conn net.Conn, network, addre
 			c.logger.Error(err)
 			return nil, err
 		}
-	case "udp", "udp4", "udp6":
-		return c.connectUDP(ctx, conn, network, address)
 	default:
 		err := fmt.Errorf("network %s is unsupported", network)
 		c.logger.Error(err)
@@ -102,35 +98,3 @@ func (c *ssConnector) Connect(ctx context.Context, conn net.Conn, network, addre
 
 	return sc, nil
 }
-
-func (c *ssConnector) connectUDP(ctx context.Context, conn net.Conn, network, address string) (net.Conn, error) {
-	if !c.md.enableUDP {
-		err := errors.New("UDP relay is disabled")
-		c.logger.Error(err)
-		return nil, err
-	}
-
-	if c.md.connectTimeout > 0 {
-		conn.SetDeadline(time.Now().Add(c.md.connectTimeout))
-		defer conn.SetDeadline(time.Time{})
-	}
-
-	taddr, _ := net.ResolveUDPAddr(network, address)
-	if taddr == nil {
-		taddr = &net.UDPAddr{}
-	}
-
-	pc, ok := conn.(net.PacketConn)
-	if ok {
-		if c.md.cipher != nil {
-			pc = c.md.cipher.PacketConn(pc)
-		}
-
-		return ss.UDPClientConn(pc, conn.RemoteAddr(), taddr, c.md.udpBufferSize), nil
-	}
-
-	if c.md.cipher != nil {
-		conn = ss.ShadowConn(c.md.cipher.StreamConn(conn), nil)
-	}
-	return socks.UDPTunClientConn(conn, taddr), nil
-}

pkg/connector/ss/metadata.go

@@ -12,8 +12,6 @@ type metadata struct {
 	cipher         core.Cipher
 	connectTimeout time.Duration
 	noDelay        bool
-	enableUDP      bool
-	udpBufferSize  int
 }
 
 func (c *ssConnector) parseMetadata(md md.Metadata) (err error) {
@@ -23,8 +21,6 @@ func (c *ssConnector) parseMetadata(md md.Metadata) (err error) {
 		key            = "key"
 		connectTimeout = "timeout"
 		noDelay        = "nodelay"
-		enableUDP      = "udp"           // enable UDP relay
-		udpBufferSize  = "udpBufferSize" // udp buffer size
 	)
 
 	c.md.cipher, err = ss.ShadowCipher(
@@ -38,18 +34,6 @@ func (c *ssConnector) parseMetadata(md md.Metadata) (err error) {
 
 	c.md.connectTimeout = md.GetDuration(connectTimeout)
 	c.md.noDelay = md.GetBool(noDelay)
-	c.md.enableUDP = md.GetBool(enableUDP)
-
-	if c.md.udpBufferSize > 0 {
-		if c.md.udpBufferSize < 512 {
-			c.md.udpBufferSize = 512
-		}
-		if c.md.udpBufferSize > 65*1024 {
-			c.md.udpBufferSize = 65 * 1024
-		}
-	} else {
-		c.md.udpBufferSize = 4096
-	}
 
 	return
 }

pkg/connector/ss/udp/connector.go

@@ -0,0 +1,84 @@
+package ss
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/go-gost/gost/pkg/common/util/socks"
+	"github.com/go-gost/gost/pkg/common/util/ss"
+	"github.com/go-gost/gost/pkg/connector"
+	"github.com/go-gost/gost/pkg/logger"
+	md "github.com/go-gost/gost/pkg/metadata"
+	"github.com/go-gost/gost/pkg/registry"
+)
+
+func init() {
+	registry.RegiserConnector("ssu", NewConnector)
+}
+
+type ssuConnector struct {
+	md     metadata
+	logger logger.Logger
+}
+
+func NewConnector(opts ...connector.Option) connector.Connector {
+	options := &connector.Options{}
+	for _, opt := range opts {
+		opt(options)
+	}
+
+	return &ssuConnector{
+		logger: options.Logger,
+	}
+}
+
+func (c *ssuConnector) Init(md md.Metadata) (err error) {
+	return c.parseMetadata(md)
+}
+
+func (c *ssuConnector) Connect(ctx context.Context, conn net.Conn, network, address string, opts ...connector.ConnectOption) (net.Conn, error) {
+	c.logger = c.logger.WithFields(map[string]interface{}{
+		"remote":  conn.RemoteAddr().String(),
+		"local":   conn.LocalAddr().String(),
+		"network": network,
+		"address": address,
+	})
+	c.logger.Infof("connect: %s/%s", address, network)
+
+	switch network {
+	case "udp", "udp4", "udp6":
+	default:
+		err := fmt.Errorf("network %s is unsupported", network)
+		c.logger.Error(err)
+		return nil, err
+	}
+
+	if c.md.connectTimeout > 0 {
+		conn.SetDeadline(time.Now().Add(c.md.connectTimeout))
+		defer conn.SetDeadline(time.Time{})
+	}
+
+	taddr, _ := net.ResolveUDPAddr(network, address)
+	if taddr == nil {
+		taddr = &net.UDPAddr{}
+	}
+
+	pc, ok := conn.(net.PacketConn)
+	if ok {
+		if c.md.cipher != nil {
+			pc = c.md.cipher.PacketConn(pc)
+		}
+
+		// standard UDP relay
+		return ss.UDPClientConn(pc, conn.RemoteAddr(), taddr, c.md.udpBufferSize), nil
+	}
+
+	if c.md.cipher != nil {
+		conn = ss.ShadowConn(c.md.cipher.StreamConn(conn), nil)
+	}
+
+	// UDP over TCP
+	return socks.UDPTunClientConn(conn, taddr), nil
+}

pkg/connector/ss/udp/metadata.go

@@ -0,0 +1,49 @@
+package ss
+
+import (
+	"time"
+
+	"github.com/go-gost/gost/pkg/common/util/ss"
+	md "github.com/go-gost/gost/pkg/metadata"
+	"github.com/shadowsocks/go-shadowsocks2/core"
+)
+
+type metadata struct {
+	cipher         core.Cipher
+	connectTimeout time.Duration
+	udpBufferSize  int
+}
+
+func (c *ssuConnector) parseMetadata(md md.Metadata) (err error) {
+	const (
+		method         = "method"
+		password       = "password"
+		key            = "key"
+		connectTimeout = "timeout"
+		udpBufferSize  = "udpBufferSize" // udp buffer size
+	)
+
+	c.md.cipher, err = ss.ShadowCipher(
+		md.GetString(method),
+		md.GetString(password),
+		md.GetString(key),
+	)
+	if err != nil {
+		return
+	}
+
+	c.md.connectTimeout = md.GetDuration(connectTimeout)
+
+	if c.md.udpBufferSize > 0 {
+		if c.md.udpBufferSize < 512 {
+			c.md.udpBufferSize = 512
+		}
+		if c.md.udpBufferSize > 65*1024 {
+			c.md.udpBufferSize = 65 * 1024
+		}
+	} else {
+		c.md.udpBufferSize = 4096
+	}
+
+	return
+}

pkg/handler/ss/handler.go

@@ -1,7 +1,6 @@
 package ss
 
 import (
-	"bufio"
 	"context"
 	"io"
 	"io/ioutil"
@@ -62,12 +61,6 @@ func (h *ssHandler) Handle(ctx context.Context, conn net.Conn) {
 		}).Infof("%s >< %s", conn.RemoteAddr(), conn.LocalAddr())
 	}()
 
-	// standard UDP relay.
-	if pc, ok := conn.(net.PacketConn); ok {
-		h.handleUDP(ctx, pc, conn.RemoteAddr())
-		return
-	}
-
 	if h.md.cipher != nil {
 		conn = ss.ShadowConn(h.md.cipher.StreamConn(conn), nil)
 	}
@@ -76,25 +69,8 @@ func (h *ssHandler) Handle(ctx context.Context, conn net.Conn) {
 		conn.SetReadDeadline(time.Now().Add(h.md.readTimeout))
 	}
 
-	br := bufio.NewReader(conn)
-	data, err := br.Peek(3)
-	conn.SetReadDeadline(time.Time{})
-	if err != nil {
-		h.logger.Error(err)
-		h.discard(conn)
-		return
-	}
-
-	conn = handler.NewBufferReaderConn(conn, br)
-	if data[2] == 0xff {
-		// UDP-over-TCP relay
-		h.handleUDPTun(ctx, conn)
-		return
-	}
-
-	// standard TCP.
 	addr := &gosocks5.Addr{}
-	if _, err = addr.ReadFrom(conn); err != nil {
+	if _, err := addr.ReadFrom(conn); err != nil {
 		h.logger.Error(err)
 		h.discard(conn)
 		return

pkg/handler/ss/metadata.go

@@ -12,8 +12,6 @@ type metadata struct {
 	cipher      core.Cipher
 	readTimeout time.Duration
 	retryCount  int
-	bufferSize  int
-	enableUDP   bool
 }
 
 func (h *ssHandler) parseMetadata(md md.Metadata) (err error) {
@@ -23,8 +21,6 @@ func (h *ssHandler) parseMetadata(md md.Metadata) (err error) {
 		key         = "key"
 		readTimeout = "readTimeout"
 		retryCount  = "retry"
-		enableUDP   = "udp"
-		bufferSize  = "bufferSize"
 	)
 
 	h.md.cipher, err = ss.ShadowCipher(
@@ -38,18 +34,6 @@ func (h *ssHandler) parseMetadata(md md.Metadata) (err error) {
 
 	h.md.readTimeout = md.GetDuration(readTimeout)
 	h.md.retryCount = md.GetInt(retryCount)
-	h.md.enableUDP = md.GetBool(enableUDP)
 
-	h.md.bufferSize = md.GetInt(bufferSize)
-	if h.md.bufferSize > 0 {
-		if h.md.bufferSize < 512 {
-			h.md.bufferSize = 512 // min buffer size
-		}
-		if h.md.bufferSize > 65*1024 {
-			h.md.bufferSize = 65 * 1024 // max buffer size
-		}
-	} else {
-		h.md.bufferSize = 4096 // default buffer size
-	}
 	return
 }

pkg/handler/ss/udp.go

@@ -1,236 +0,0 @@
-package ss
-
-import (
-	"context"
-	"net"
-	"time"
-
-	"github.com/go-gost/gost/pkg/chain"
-	"github.com/go-gost/gost/pkg/common/bufpool"
-	"github.com/go-gost/gost/pkg/common/util/socks"
-	"github.com/go-gost/gost/pkg/common/util/ss"
-)
-
-func (h *ssHandler) handleUDP(ctx context.Context, conn net.PacketConn, raddr net.Addr) {
-	if !h.md.enableUDP {
-		h.logger.Error("UDP relay is diabled")
-		return
-	}
-
-	if h.md.cipher != nil {
-		conn = h.md.cipher.PacketConn(conn)
-	}
-
-	// obtain a udp connection
-	r := (&chain.Router{}).
-		WithChain(h.chain).
-		WithRetry(h.md.retryCount).
-		WithLogger(h.logger)
-	c, err := r.Dial(ctx, "udp", "")
-	if err != nil {
-		h.logger.Error(err)
-		return
-	}
-
-	cc, ok := c.(net.PacketConn)
-	if !ok {
-		h.logger.Errorf("%s: not a packet connection")
-		return
-	}
-	defer cc.Close()
-
-	h.logger = h.logger.WithFields(map[string]interface{}{
-		"bind": cc.LocalAddr().String(),
-	})
-	h.logger.Infof("bind on %s OK", cc.LocalAddr().String())
-	t := time.Now()
-	h.logger.Infof("%s <-> %s", raddr, cc.LocalAddr())
-	h.relayPacket(
-		ss.UDPServerConn(conn, raddr, h.md.bufferSize),
-		cc,
-	)
-	h.logger.
-		WithFields(map[string]interface{}{"duration": time.Since(t)}).
-		Infof("%s >-< %s", raddr, cc.LocalAddr())
-}
-
-func (h *ssHandler) handleUDPTun(ctx context.Context, conn net.Conn) {
-	if !h.md.enableUDP {
-		h.logger.Error("UDP relay is diabled")
-		return
-	}
-
-	// obtain a udp connection
-	r := (&chain.Router{}).
-		WithChain(h.chain).
-		WithRetry(h.md.retryCount).
-		WithLogger(h.logger)
-	c, err := r.Dial(ctx, "udp", "")
-	if err != nil {
-		h.logger.Error(err)
-		return
-	}
-
-	cc, ok := c.(net.PacketConn)
-	if !ok {
-		h.logger.Errorf("%s: not a packet connection")
-		return
-	}
-	defer cc.Close()
-
-	h.logger = h.logger.WithFields(map[string]interface{}{
-		"bind": cc.LocalAddr().String(),
-	})
-	h.logger.Infof("bind on %s OK", cc.LocalAddr().String())
-
-	t := time.Now()
-	h.logger.Infof("%s <-> %s", conn.RemoteAddr(), cc.LocalAddr())
-	h.tunnelUDP(socks.UDPTunServerConn(conn), cc)
-	h.logger.
-		WithFields(map[string]interface{}{"duration": time.Since(t)}).
-		Infof("%s >-< %s", conn.RemoteAddr(), cc.LocalAddr())
-}
-
-func (h *ssHandler) relayPacket(pc1, pc2 net.PacketConn) (err error) {
-	bufSize := h.md.bufferSize
-	errc := make(chan error, 2)
-
-	go func() {
-		for {
-			err := func() error {
-				b := bufpool.Get(bufSize)
-				defer bufpool.Put(b)
-
-				n, addr, err := pc1.ReadFrom(b)
-				if err != nil {
-					return err
-				}
-
-				if h.bypass != nil && h.bypass.Contains(addr.String()) {
-					h.logger.Warn("bypass: ", addr)
-					return nil
-				}
-
-				if _, err = pc2.WriteTo(b[:n], addr); err != nil {
-					return err
-				}
-
-				h.logger.Debugf("%s >>> %s data: %d",
-					pc2.LocalAddr(), addr, n)
-				return nil
-			}()
-
-			if err != nil {
-				errc <- err
-				return
-			}
-		}
-	}()
-
-	go func() {
-		for {
-			err := func() error {
-				b := bufpool.Get(bufSize)
-				defer bufpool.Put(b)
-
-				n, raddr, err := pc2.ReadFrom(b)
-				if err != nil {
-					return err
-				}
-
-				if h.bypass != nil && h.bypass.Contains(raddr.String()) {
-					h.logger.Warn("bypass: ", raddr)
-					return nil
-				}
-
-				if _, err = pc1.WriteTo(b[:n], raddr); err != nil {
-					return err
-				}
-
-				h.logger.Debugf("%s <<< %s data: %d",
-					pc2.LocalAddr(), raddr, n)
-				return nil
-			}()
-
-			if err != nil {
-				errc <- err
-				return
-			}
-		}
-	}()
-
-	return <-errc
-}
-
-func (h *ssHandler) tunnelUDP(tunnel, c net.PacketConn) (err error) {
-	bufSize := h.md.bufferSize
-	errc := make(chan error, 2)
-
-	go func() {
-		b := bufpool.Get(bufSize)
-		defer bufpool.Put(b)
-
-		for {
-			err := func() error {
-				n, addr, err := tunnel.ReadFrom(b)
-				if err != nil {
-					return err
-				}
-
-				if h.bypass != nil && h.bypass.Contains(addr.String()) {
-					h.logger.Warn("bypass: ", addr.String())
-					return nil // bypass
-				}
-
-				if _, err := c.WriteTo(b[:n], addr); err != nil {
-					return err
-				}
-
-				h.logger.Debugf("%s >>> %s data: %d",
-					c.LocalAddr(), addr, n)
-
-				return nil
-			}()
-
-			if err != nil {
-				errc <- err
-				return
-			}
-		}
-	}()
-
-	go func() {
-		b := bufpool.Get(bufSize)
-		defer bufpool.Put(b)
-
-		for {
-			err := func() error {
-				n, raddr, err := c.ReadFrom(b)
-				if err != nil {
-					return err
-				}
-
-				if h.bypass != nil && h.bypass.Contains(raddr.String()) {
-					h.logger.Warn("bypass: ", raddr.String())
-					return nil // bypass
-				}
-
-				if _, err := tunnel.WriteTo(b[:n], raddr); err != nil {
-					return err
-				}
-
-				h.logger.Debugf("%s <<< %s data: %d",
-					c.LocalAddr(), raddr, n)
-
-				return nil
-			}()
-
-			if err != nil {
-				errc <- err
-				return
-			}
-		}
-	}()
-
-	return <-errc
-}

pkg/handler/ss/udp/handler.go

@@ -0,0 +1,173 @@
+package ss
+
+import (
+	"context"
+	"net"
+	"time"
+
+	"github.com/go-gost/gost/pkg/bypass"
+	"github.com/go-gost/gost/pkg/chain"
+	"github.com/go-gost/gost/pkg/common/bufpool"
+	"github.com/go-gost/gost/pkg/common/util/socks"
+	"github.com/go-gost/gost/pkg/common/util/ss"
+	"github.com/go-gost/gost/pkg/handler"
+	"github.com/go-gost/gost/pkg/logger"
+	md "github.com/go-gost/gost/pkg/metadata"
+	"github.com/go-gost/gost/pkg/registry"
+)
+
+func init() {
+	registry.RegisterHandler("ssu", NewHandler)
+}
+
+type ssuHandler struct {
+	chain  *chain.Chain
+	bypass bypass.Bypass
+	logger logger.Logger
+	md     metadata
+}
+
+func NewHandler(opts ...handler.Option) handler.Handler {
+	options := &handler.Options{}
+	for _, opt := range opts {
+		opt(options)
+	}
+
+	return &ssuHandler{
+		chain:  options.Chain,
+		bypass: options.Bypass,
+		logger: options.Logger,
+	}
+}
+
+func (h *ssuHandler) Init(md md.Metadata) (err error) {
+	return h.parseMetadata(md)
+}
+
+func (h *ssuHandler) Handle(ctx context.Context, conn net.Conn) {
+	defer conn.Close()
+
+	start := time.Now()
+	h.logger = h.logger.WithFields(map[string]interface{}{
+		"remote": conn.RemoteAddr().String(),
+		"local":  conn.LocalAddr().String(),
+	})
+
+	h.logger.Infof("%s <> %s", conn.RemoteAddr(), conn.LocalAddr())
+	defer func() {
+		h.logger.WithFields(map[string]interface{}{
+			"duration": time.Since(start),
+		}).Infof("%s >< %s", conn.RemoteAddr(), conn.LocalAddr())
+	}()
+
+	pc, ok := conn.(net.PacketConn)
+	if ok {
+		if h.md.cipher != nil {
+			pc = h.md.cipher.PacketConn(pc)
+		}
+		// standard UDP relay.
+		pc = ss.UDPServerConn(pc, conn.RemoteAddr(), h.md.bufferSize)
+	} else {
+		if h.md.cipher != nil {
+			conn = ss.ShadowConn(h.md.cipher.StreamConn(conn), nil)
+		}
+		// UDP over TCP
+		pc = socks.UDPTunServerConn(conn)
+	}
+
+	// obtain a udp connection
+	r := (&chain.Router{}).
+		WithChain(h.chain).
+		WithRetry(h.md.retryCount).
+		WithLogger(h.logger)
+	c, err := r.Dial(ctx, "udp", "")
+	if err != nil {
+		h.logger.Error(err)
+		return
+	}
+
+	cc, ok := c.(net.PacketConn)
+	if !ok {
+		h.logger.Errorf("%s: not a packet connection")
+		return
+	}
+	defer cc.Close()
+
+	t := time.Now()
+	h.logger.Infof("%s <-> %s", conn.RemoteAddr(), cc.LocalAddr())
+	h.relayPacket(pc, cc)
+	h.logger.
+		WithFields(map[string]interface{}{"duration": time.Since(t)}).
+		Infof("%s >-< %s", conn.RemoteAddr(), cc.LocalAddr())
+}
+
+func (h *ssuHandler) relayPacket(pc1, pc2 net.PacketConn) (err error) {
+	bufSize := h.md.bufferSize
+	errc := make(chan error, 2)
+
+	go func() {
+		for {
+			err := func() error {
+				b := bufpool.Get(bufSize)
+				defer bufpool.Put(b)
+
+				n, addr, err := pc1.ReadFrom(b)
+				if err != nil {
+					return err
+				}
+
+				if h.bypass != nil && h.bypass.Contains(addr.String()) {
+					h.logger.Warn("bypass: ", addr)
+					return nil
+				}
+
+				if _, err = pc2.WriteTo(b[:n], addr); err != nil {
+					return err
+				}
+
+				h.logger.Debugf("%s >>> %s data: %d",
+					pc2.LocalAddr(), addr, n)
+				return nil
+			}()
+
+			if err != nil {
+				errc <- err
+				return
+			}
+		}
+	}()
+
+	go func() {
+		for {
+			err := func() error {
+				b := bufpool.Get(bufSize)
+				defer bufpool.Put(b)
+
+				n, raddr, err := pc2.ReadFrom(b)
+				if err != nil {
+					return err
+				}
+
+				if h.bypass != nil && h.bypass.Contains(raddr.String()) {
+					h.logger.Warn("bypass: ", raddr)
+					return nil
+				}
+
+				if _, err = pc1.WriteTo(b[:n], raddr); err != nil {
+					return err
+				}
+
+				h.logger.Debugf("%s <<< %s data: %d",
+					pc2.LocalAddr(), raddr, n)
+				return nil
+			}()
+
+			if err != nil {
+				errc <- err
+				return
+			}
+		}
+	}()
+
+	return <-errc
+}

pkg/handler/ss/udp/metadata.go

@@ -0,0 +1,52 @@
+package ss
+
+import (
+	"time"
+
+	"github.com/go-gost/gost/pkg/common/util/ss"
+	md "github.com/go-gost/gost/pkg/metadata"
+	"github.com/shadowsocks/go-shadowsocks2/core"
+)
+
+type metadata struct {
+	cipher      core.Cipher
+	readTimeout time.Duration
+	retryCount  int
+	bufferSize  int
+}
+
+func (h *ssuHandler) parseMetadata(md md.Metadata) (err error) {
+	const (
+		method      = "method"
+		password    = "password"
+		key         = "key"
+		readTimeout = "readTimeout"
+		retryCount  = "retry"
+		bufferSize  = "bufferSize"
+	)
+
+	h.md.cipher, err = ss.ShadowCipher(
+		md.GetString(method),
+		md.GetString(password),
+		md.GetString(key),
+	)
+	if err != nil {
+		return
+	}
+
+	h.md.readTimeout = md.GetDuration(readTimeout)
+	h.md.retryCount = md.GetInt(retryCount)
+
+	h.md.bufferSize = md.GetInt(bufferSize)
+	if h.md.bufferSize > 0 {
+		if h.md.bufferSize < 512 {
+			h.md.bufferSize = 512 // min buffer size
+		}
+		if h.md.bufferSize > 65*1024 {
+			h.md.bufferSize = 65 * 1024 // max buffer size
+		}
+	} else {
+		h.md.bufferSize = 4096 // default buffer size
+	}
+	return
+}