Refactor: new dialer impl

common/singledo/singledo.go

@@ -0,0 +1,66 @@
+package singledo
+
+// Ref: github.com/Dreamacro/clash/common/singledo
+
+import (
+	"sync"
+	"time"
+)
+
+type call struct {
+	wg  sync.WaitGroup
+	val any
+	err error
+}
+
+type Single struct {
+	mux    sync.Mutex
+	last   time.Time
+	wait   time.Duration
+	call   *call
+	result *Result
+}
+
+type Result struct {
+	Val any
+	Err error
+}
+
+// Do single.Do likes sync.singleFlight
+//lint:ignore ST1008 it likes sync.singleFlight
+func (s *Single) Do(fn func() (any, error)) (v any, err error, shared bool) {
+	s.mux.Lock()
+	now := time.Now()
+	if now.Before(s.last.Add(s.wait)) {
+		s.mux.Unlock()
+		return s.result.Val, s.result.Err, true
+	}
+
+	if call := s.call; call != nil {
+		s.mux.Unlock()
+		call.wg.Wait()
+		return call.val, call.err, true
+	}
+
+	call := &call{}
+	call.wg.Add(1)
+	s.call = call
+	s.mux.Unlock()
+	call.val, call.err = fn()
+	call.wg.Done()
+
+	s.mux.Lock()
+	s.call = nil
+	s.result = &Result{call.val, call.err}
+	s.last = now
+	s.mux.Unlock()
+	return call.val, call.err, false
+}
+
+func (s *Single) Reset() {
+	s.last = time.Time{}
+}
+
+func NewSingle(wait time.Duration) *Single {
+	return &Single{wait: wait}
+}

common/singledo/singledo_test.go

@@ -0,0 +1,69 @@
+package singledo
+
+import (
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"go.uber.org/atomic"
+)
+
+func TestBasic(t *testing.T) {
+	single := NewSingle(time.Millisecond * 30)
+	foo := 0
+	shardCount := atomic.NewInt32(0)
+	call := func() (any, error) {
+		foo++
+		time.Sleep(time.Millisecond * 5)
+		return nil, nil
+	}
+
+	var wg sync.WaitGroup
+	const n = 5
+	wg.Add(n)
+	for i := 0; i < n; i++ {
+		go func() {
+			_, _, shard := single.Do(call)
+			if shard {
+				shardCount.Inc()
+			}
+			wg.Done()
+		}()
+	}
+
+	wg.Wait()
+	assert.Equal(t, 1, foo)
+	assert.Equal(t, int32(4), shardCount.Load())
+}
+
+func TestTimer(t *testing.T) {
+	single := NewSingle(time.Millisecond * 30)
+	foo := 0
+	call := func() (any, error) {
+		foo++
+		return nil, nil
+	}
+
+	single.Do(call)
+	time.Sleep(10 * time.Millisecond)
+	_, _, shard := single.Do(call)
+
+	assert.Equal(t, 1, foo)
+	assert.True(t, shard)
+}
+
+func TestReset(t *testing.T) {
+	single := NewSingle(time.Millisecond * 30)
+	foo := 0
+	call := func() (any, error) {
+		foo++
+		return nil, nil
+	}
+
+	single.Do(call)
+	single.Reset()
+	single.Do(call)
+
+	assert.Equal(t, 2, foo)
+}

component/dialer/bind.go

@@ -1,21 +0,0 @@
-package dialer
-
-import (
-	"net"
-	"sync"
-)
-
-var _bindOnce sync.Once
-
-// BindToInterface binds dialer to specific interface.
-func BindToInterface(name string) error {
-	i, err := net.InterfaceByName(name)
-	if err != nil {
-		return err
-	}
-
-	_bindOnce.Do(func() {
-		addControl(bindToInterface(i))
-	})
-	return nil
-}

component/dialer/bind_darwin.go

@@ -1,32 +0,0 @@
-package dialer
-
-import (
-	"net"
-	"syscall"
-
-	"golang.org/x/sys/unix"
-)
-
-func bindToInterface(i *net.Interface) controlFunc {
-	return func(network, address string, c syscall.RawConn) (err error) {
-		host, _, _ := net.SplitHostPort(address)
-		if ip := net.ParseIP(host); ip != nil && !ip.IsGlobalUnicast() {
-			return
-		}
-
-		var innerErr error
-		err = c.Control(func(fd uintptr) {
-			switch network {
-			case "tcp4", "udp4":
-				innerErr = unix.SetsockoptInt(int(fd), syscall.IPPROTO_IP, syscall.IP_BOUND_IF, i.Index)
-			case "tcp6", "udp6":
-				innerErr = unix.SetsockoptInt(int(fd), syscall.IPPROTO_IPV6, syscall.IPV6_BOUND_IF, i.Index)
-			}
-		})
-
-		if innerErr != nil {
-			err = innerErr
-		}
-		return
-	}
-}

component/dialer/bind_linux.go

@@ -1,27 +0,0 @@
-package dialer
-
-import (
-	"net"
-	"syscall"
-
-	"golang.org/x/sys/unix"
-)
-
-func bindToInterface(i *net.Interface) controlFunc {
-	return func(network, address string, c syscall.RawConn) (err error) {
-		host, _, _ := net.SplitHostPort(address)
-		if ip := net.ParseIP(host); ip != nil && !ip.IsGlobalUnicast() {
-			return nil
-		}
-
-		var innerErr error
-		err = c.Control(func(fd uintptr) {
-			innerErr = unix.BindToDevice(int(fd), i.Name)
-		})
-
-		if innerErr != nil {
-			err = innerErr
-		}
-		return
-	}
-}

component/dialer/bind_others.go

@@ -1,15 +0,0 @@
-//go:build !linux && !darwin
-
-package dialer
-
-import (
-	"errors"
-	"net"
-	"syscall"
-)
-
-func bindToInterface(_ *net.Interface) controlFunc {
-	return func(string, string, syscall.RawConn) error {
-		return errors.New("unsupported platform")
-	}
-}

component/dialer/control.go

@@ -1,35 +0,0 @@
-package dialer
-
-import (
-	"errors"
-	"net"
-	"syscall"
-)
-
-type controlFunc func(string, string, syscall.RawConn) error
-
-var _controlPool = make([]controlFunc, 0, 2)
-
-func addControl(f controlFunc) {
-	_controlPool = append(_controlPool, f)
-}
-
-func setControl(i any) {
-	control := func(address, network string, c syscall.RawConn) error {
-		for _, f := range _controlPool {
-			if err := f(address, network, c); err != nil {
-				return err
-			}
-		}
-		return nil
-	}
-
-	switch v := i.(type) {
-	case *net.Dialer:
-		v.Control = control
-	case *net.ListenConfig:
-		v.Control = control
-	default:
-		panic(errors.New("wrong type"))
-	}
-}

component/dialer/dialer.go

@@ -3,20 +3,56 @@ package dialer
 import (
 	"context"
 	"net"
+	"syscall"
+
+	"go.uber.org/atomic"
 )
 
-func Dial(network, address string) (net.Conn, error) {
+var (
-	return DialContext(context.Background(), network, address)
+	DefaultInterfaceName = atomic.NewString("")
+	DefaultRoutingMark   = atomic.NewInt32(0)
+)
+
+type Options struct {
+	// InterfaceName is the name of interface/device to bind.
+	// If a socket is bound to an interface, only packets received
+	// from that particular interface are processed by the socket.
+	InterfaceName string
+
+	// RoutingMark is the mark for each packet sent through this
+	// socket. Changing the mark can be used for mark-based routing
+	// without netfilter or for packet filtering.
+	RoutingMark int
 }
 
 func DialContext(ctx context.Context, network, address string) (net.Conn, error) {
-	d := &net.Dialer{}
+	return DialContextWithOptions(ctx, network, address, &Options{
-	setControl(d)
+		InterfaceName: DefaultInterfaceName.Load(),
+		RoutingMark:   int(DefaultRoutingMark.Load()),
+	})
+}
+
+func DialContextWithOptions(ctx context.Context, network, address string, opts *Options) (net.Conn, error) {
+	d := &net.Dialer{
+		Control: func(network, address string, c syscall.RawConn) error {
+			return setSocketOptions(network, address, c, opts)
+		},
+	}
 	return d.DialContext(ctx, network, address)
 }
 
 func ListenPacket(network, address string) (net.PacketConn, error) {
-	lc := &net.ListenConfig{}
+	return ListenPacketWithOptions(network, address, &Options{
-	setControl(lc)
+		InterfaceName: DefaultInterfaceName.Load(),
+		RoutingMark:   int(DefaultRoutingMark.Load()),
+	})
+}
+
+func ListenPacketWithOptions(network, address string, opts *Options) (net.PacketConn, error) {
+	lc := &net.ListenConfig{
+		Control: func(network, address string, c syscall.RawConn) error {
+			return setSocketOptions(network, address, c, opts)
+		},
+	}
 	return lc.ListenPacket(context.Background(), network, address)
 }

component/dialer/fwmark.go

@@ -1,14 +0,0 @@
-package dialer
-
-import (
-	"sync"
-)
-
-var _setOnce sync.Once
-
-// SetMark sets the mark for each packet sent through this dialer(socket).
-func SetMark(i int) {
-	_setOnce.Do(func() {
-		addControl(setMark(i))
-	})
-}

component/dialer/fwmark_linux.go

@@ -1,21 +0,0 @@
-package dialer
-
-import (
-	"syscall"
-
-	"golang.org/x/sys/unix"
-)
-
-func setMark(m int) controlFunc {
-	return func(_, _ string, c syscall.RawConn) (err error) {
-		var innerErr error
-		err = c.Control(func(fd uintptr) {
-			innerErr = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_MARK, m)
-		})
-
-		if innerErr != nil {
-			err = innerErr
-		}
-		return
-	}
-}

component/dialer/fwmark_others.go

@@ -1,14 +0,0 @@
-//go:build !linux
-
-package dialer
-
-import (
-	"errors"
-	"syscall"
-)
-
-func setMark(_ int) controlFunc {
-	return func(string, string, syscall.RawConn) error {
-		return errors.New("fwmark: linux only")
-	}
-}

component/dialer/sockopt.go

@@ -0,0 +1,19 @@
+package dialer
+
+func isTCPSocket(network string) bool {
+	switch network {
+	case "tcp", "tcp4", "tcp6":
+		return true
+	default:
+		return false
+	}
+}
+
+func isUDPSocket(network string) bool {
+	switch network {
+	case "udp", "udp4", "udp6":
+		return true
+	default:
+		return false
+	}
+}

component/dialer/sockopt_darwin.go

@@ -0,0 +1,61 @@
+package dialer
+
+import (
+	"net"
+	"syscall"
+	"time"
+
+	"github.com/xjasonlyu/tun2socks/v2/common/singledo"
+
+	"golang.org/x/sys/unix"
+)
+
+var interfaces = singledo.NewSingle(30 * time.Second)
+
+func resolveInterfaceByName(name string) (*net.Interface, error) {
+	value, err, _ := interfaces.Do(func() (any, error) {
+		return net.InterfaceByName(name)
+	})
+	if err != nil {
+		return nil, err
+	}
+	return value.(*net.Interface), nil
+}
+
+func setSocketOptions(network, address string, c syscall.RawConn, opts *Options) (err error) {
+	if !isTCPSocket(network) && !isUDPSocket(network) {
+		return
+	}
+
+	var innerErr error
+	err = c.Control(func(fd uintptr) {
+		// must be GlobalUnicast.
+		host, _, _ := net.SplitHostPort(address)
+		if ip := net.ParseIP(host); ip != nil && !ip.IsGlobalUnicast() {
+			return
+		}
+
+		if opts.InterfaceName != "" {
+			var iface *net.Interface
+			iface, innerErr = resolveInterfaceByName(opts.InterfaceName)
+			if innerErr != nil {
+				return
+			}
+
+			switch network {
+			case "tcp4", "udp4":
+				innerErr = unix.SetsockoptInt(int(fd), syscall.IPPROTO_IP, syscall.IP_BOUND_IF, iface.Index)
+			case "tcp6", "udp6":
+				innerErr = unix.SetsockoptInt(int(fd), syscall.IPPROTO_IPV6, syscall.IPV6_BOUND_IF, iface.Index)
+			}
+			if innerErr != nil {
+				return
+			}
+		}
+	})
+
+	if innerErr != nil {
+		err = innerErr
+	}
+	return
+}

component/dialer/sockopt_linux.go

@@ -0,0 +1,39 @@
+package dialer
+
+import (
+	"net"
+	"syscall"
+
+	"golang.org/x/sys/unix"
+)
+
+func setSocketOptions(network, address string, c syscall.RawConn, opts *Options) (err error) {
+	if !isTCPSocket(network) && !isUDPSocket(network) {
+		return
+	}
+
+	var innerErr error
+	err = c.Control(func(fd uintptr) {
+		// must be GlobalUnicast.
+		host, _, _ := net.SplitHostPort(address)
+		if ip := net.ParseIP(host); ip != nil && !ip.IsGlobalUnicast() {
+			return
+		}
+
+		if opts.InterfaceName != "" {
+			if innerErr = unix.BindToDevice(int(fd), opts.InterfaceName); innerErr != nil {
+				return
+			}
+		}
+		if opts.RoutingMark != 0 {
+			if innerErr = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, unix.SO_MARK, opts.RoutingMark); innerErr != nil {
+				return
+			}
+		}
+	})
+
+	if innerErr != nil {
+		err = innerErr
+	}
+	return
+}

component/dialer/sockopt_others.go

@@ -0,0 +1,7 @@
+//go:build !linux && !darwin
+
+package dialer
+
+func setSocketOptions(network, address string, c syscall.RawConn, opts *Options) error {
+	return nil
+}

engine/engine.go

@@ -65,8 +65,7 @@ func (e *engine) start() error {
 
 	for _, f := range []func() error{
 		e.applyLogLevel,
-		e.applyMark,
+		e.applyDialer,
-		e.applyInterface,
 		e.applyStats,
 		e.applyUDPTimeout,
 		e.applyProxy,
@@ -104,21 +103,15 @@ func (e *engine) applyLogLevel() error {
 	return nil
 }
 
-func (e *engine) applyMark() error {
+func (e *engine) applyDialer() error {
-	if e.Mark != 0 {
-		dialer.SetMark(e.Mark)
-		log.Infof("[DIALER] set fwmark: %#x", e.Mark)
-	}
-	return nil
-}
-
-func (e *engine) applyInterface() error {
 	if e.Interface != "" {
-		if err := dialer.BindToInterface(e.Interface); err != nil {
+		dialer.DefaultInterfaceName.Store(e.Interface)
-			return err
-		}
 		log.Infof("[DIALER] bind to interface: %s", e.Interface)
 	}
+	if e.Mark != 0 {
+		dialer.DefaultRoutingMark.Store(int32(e.Mark))
+		log.Infof("[DIALER] set fwmark: %#x", e.Mark)
+	}
 	return nil
 }