Feature: use native syscall to bind interface on Linux and macOS

component/dialer/bind.go

@@ -0,0 +1,104 @@
+package dialer
+
+import (
+	"errors"
+	"net"
+)
+
+var (
+	errPlatformNotSupport = errors.New("unsupport platform")
+)
+
+func lookupTCPAddr(ip net.IP, addrs []net.Addr) (*net.TCPAddr, error) {
+	ipv4 := ip.To4() != nil
+
+	for _, elm := range addrs {
+		addr, ok := elm.(*net.IPNet)
+		if !ok {
+			continue
+		}
+
+		addrV4 := addr.IP.To4() != nil
+
+		if addrV4 && ipv4 {
+			return &net.TCPAddr{IP: addr.IP, Port: 0}, nil
+		} else if !addrV4 && !ipv4 {
+			return &net.TCPAddr{IP: addr.IP, Port: 0}, nil
+		}
+	}
+
+	return nil, ErrAddrNotFound
+}
+
+func lookupUDPAddr(ip net.IP, addrs []net.Addr) (*net.UDPAddr, error) {
+	ipv4 := ip.To4() != nil
+
+	for _, elm := range addrs {
+		addr, ok := elm.(*net.IPNet)
+		if !ok {
+			continue
+		}
+
+		addrV4 := addr.IP.To4() != nil
+
+		if addrV4 && ipv4 {
+			return &net.UDPAddr{IP: addr.IP, Port: 0}, nil
+		} else if !addrV4 && !ipv4 {
+			return &net.UDPAddr{IP: addr.IP, Port: 0}, nil
+		}
+	}
+
+	return nil, ErrAddrNotFound
+}
+
+func fallbackBindToDialer(dialer *net.Dialer, network string, ip net.IP, name string) error {
+	iface, err := net.InterfaceByName(name)
+	if err != nil {
+		return err
+	}
+
+	addrs, err := iface.Addrs()
+	if err != nil {
+		return err
+	}
+
+	switch network {
+	case "tcp", "tcp4", "tcp6":
+		if addr, err := lookupTCPAddr(ip, addrs); err == nil {
+			dialer.LocalAddr = addr
+		} else {
+			return err
+		}
+	case "udp", "udp4", "udp6":
+		if addr, err := lookupUDPAddr(ip, addrs); err == nil {
+			dialer.LocalAddr = addr
+		} else {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func fallbackBindToListenConfig(name string) (string, error) {
+	iface, err := net.InterfaceByName(name)
+	if err != nil {
+		return "", err
+	}
+
+	addrs, err := iface.Addrs()
+	if err != nil {
+		return "", err
+	}
+
+	for _, elm := range addrs {
+		addr, ok := elm.(*net.IPNet)
+		if !ok || addr.IP.To4() == nil {
+			continue
+		}
+
+		return net.JoinHostPort(addr.IP.String(), "0"), nil
+	}
+
+	return "", ErrAddrNotFound
+}

component/dialer/bind_darwin.go

@@ -0,0 +1,46 @@
+package dialer
+
+import (
+	"net"
+	"syscall"
+)
+
+func bindIfaceToDialer(dialer *net.Dialer, ifaceName string) error {
+	iface, err := net.InterfaceByName(ifaceName)
+	if err != nil {
+		return err
+	}
+
+	dialer.Control = func(network, address string, c syscall.RawConn) error {
+		return c.Control(func(fd uintptr) {
+			switch network {
+			case "tcp4", "udp4":
+				syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IP, syscall.IP_BOUND_IF, iface.Index)
+			case "tcp6", "udp6":
+				syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IPV6, syscall.IPV6_BOUND_IF, iface.Index)
+			}
+		})
+	}
+
+	return nil
+}
+
+func bindIfaceToListenConfig(lc *net.ListenConfig, ifaceName string) error {
+	iface, err := net.InterfaceByName(ifaceName)
+	if err != nil {
+		return err
+	}
+
+	lc.Control = func(network, address string, c syscall.RawConn) error {
+		return c.Control(func(fd uintptr) {
+			switch network {
+			case "tcp4", "udp4":
+				syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IP, syscall.IP_BOUND_IF, iface.Index)
+			case "tcp6", "udp6":
+				syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IPV6, syscall.IPV6_BOUND_IF, iface.Index)
+			}
+		})
+	}
+
+	return nil
+}

component/dialer/bind_linux.go

@@ -0,0 +1,26 @@
+package dialer
+
+import (
+	"net"
+	"syscall"
+)
+
+func bindIfaceToDialer(dialer *net.Dialer, ifaceName string) error {
+	dialer.Control = func(network, address string, c syscall.RawConn) error {
+		return c.Control(func(fd uintptr) {
+			syscall.BindToDevice(int(fd), ifaceName)
+		})
+	}
+
+	return nil
+}
+
+func bindIfaceToListenConfig(lc *net.ListenConfig, ifaceName string) error {
+	lc.Control = func(network, address string, c syscall.RawConn) error {
+		return c.Control(func(fd uintptr) {
+			syscall.BindToDevice(int(fd), ifaceName)
+		})
+	}
+
+	return nil
+}

component/dialer/bind_others.go

@@ -0,0 +1,13 @@
+// +build !linux,!darwin
+
+package dialer
+
+import "net"
+
+func bindIfaceToDialer(dialer *net.Dialer, ifaceName string) error {
+	return errNotSupport
+}
+
+func bindIfaceToListenConfig(lc *net.ListenConfig, ifaceName string) error {
+	return errNotSupport
+}

component/dialer/dialer.go

@@ -19,17 +19,6 @@ func Dialer() (*net.Dialer, error) {
 	return dialer, nil
 }
 
-func ListenConfig() (*net.ListenConfig, error) {
-	cfg := &net.ListenConfig{}
-	if ListenConfigHook != nil {
-		if err := ListenConfigHook(cfg); err != nil {
-			return nil, err
-		}
-	}
-
-	return cfg, nil
-}
-
 func Dial(network, address string) (net.Conn, error) {
 	return DialContext(context.Background(), network, address)
 }
@@ -73,19 +62,16 @@ func DialContext(ctx context.Context, network, address string) (net.Conn, error)
 }
 
 func ListenPacket(network, address string) (net.PacketConn, error) {
-	lc, err := ListenConfig()
+	cfg := &net.ListenConfig{}
+	if ListenPacketHook != nil {
+		var err error
+		address, err = ListenPacketHook(cfg, address)
 		if err != nil {
 			return nil, err
 		}
+	}
 
-	if ListenPacketHook != nil && address == "" {
+	return cfg.ListenPacket(context.Background(), network, address)
-		ip, err := ListenPacketHook()
-		if err != nil {
-			return nil, err
-		}
-		address = net.JoinHostPort(ip.String(), "0")
-	}
-	return lc.ListenPacket(context.Background(), network, address)
 }
 
 func dualStackDialContext(ctx context.Context, network, address string) (net.Conn, error) {

component/dialer/hook.go

@@ -3,20 +3,15 @@ package dialer
 import (
 	"errors"
 	"net"
-	"time"
-
-	"github.com/Dreamacro/clash/common/singledo"
 )
 
 type DialerHookFunc = func(dialer *net.Dialer) error
 type DialHookFunc = func(dialer *net.Dialer, network string, ip net.IP) error
-type ListenConfigHookFunc = func(*net.ListenConfig) error
+type ListenPacketHookFunc = func(lc *net.ListenConfig, address string) (string, error)
-type ListenPacketHookFunc = func() (net.IP, error)
 
 var (
 	DialerHook       DialerHookFunc
 	DialHook         DialHookFunc
-	ListenConfigHook ListenConfigHookFunc
 	ListenPacketHook ListenPacketHookFunc
 )
 
@@ -25,124 +20,24 @@ var (
 	ErrNetworkNotSupport = errors.New("network not support")
 )
 
-func lookupTCPAddr(ip net.IP, addrs []net.Addr) (*net.TCPAddr, error) {
-	ipv4 := ip.To4() != nil
-
-	for _, elm := range addrs {
-		addr, ok := elm.(*net.IPNet)
-		if !ok {
-			continue
-		}
-
-		addrV4 := addr.IP.To4() != nil
-
-		if addrV4 && ipv4 {
-			return &net.TCPAddr{IP: addr.IP, Port: 0}, nil
-		} else if !addrV4 && !ipv4 {
-			return &net.TCPAddr{IP: addr.IP, Port: 0}, nil
-		}
-	}
-
-	return nil, ErrAddrNotFound
-}
-
-func lookupUDPAddr(ip net.IP, addrs []net.Addr) (*net.UDPAddr, error) {
-	ipv4 := ip.To4() != nil
-
-	for _, elm := range addrs {
-		addr, ok := elm.(*net.IPNet)
-		if !ok {
-			continue
-		}
-
-		addrV4 := addr.IP.To4() != nil
-
-		if addrV4 && ipv4 {
-			return &net.UDPAddr{IP: addr.IP, Port: 0}, nil
-		} else if !addrV4 && !ipv4 {
-			return &net.UDPAddr{IP: addr.IP, Port: 0}, nil
-		}
-	}
-
-	return nil, ErrAddrNotFound
-}
-
 func ListenPacketWithInterface(name string) ListenPacketHookFunc {
-	single := singledo.NewSingle(5 * time.Second)
+	return func(lc *net.ListenConfig, address string) (string, error) {
-
+		err := bindIfaceToListenConfig(lc, name)
-	return func() (net.IP, error) {
+		if err == errPlatformNotSupport {
-		elm, err, _ := single.Do(func() (interface{}, error) {
+			address, err = fallbackBindToListenConfig(name)
-			iface, err := net.InterfaceByName(name)
-			if err != nil {
-				return nil, err
 		}
 
-			addrs, err := iface.Addrs()
+		return address, err
-			if err != nil {
-				return nil, err
-			}
-
-			return addrs, nil
-		})
-
-		if err != nil {
-			return nil, err
-		}
-
-		addrs := elm.([]net.Addr)
-
-		for _, elm := range addrs {
-			addr, ok := elm.(*net.IPNet)
-			if !ok || addr.IP.To4() == nil {
-				continue
-			}
-
-			return addr.IP, nil
-		}
-
-		return nil, ErrAddrNotFound
 	}
 }
 
 func DialerWithInterface(name string) DialHookFunc {
-	single := singledo.NewSingle(5 * time.Second)
-
 	return func(dialer *net.Dialer, network string, ip net.IP) error {
-		elm, err, _ := single.Do(func() (interface{}, error) {
+		err := bindIfaceToDialer(dialer, name)
-			iface, err := net.InterfaceByName(name)
+		if err == errPlatformNotSupport {
-			if err != nil {
+			err = fallbackBindToDialer(dialer, network, ip, name)
-				return nil, err
 		}
 
-			addrs, err := iface.Addrs()
-			if err != nil {
-				return nil, err
-			}
-
-			return addrs, nil
-		})
-
-		if err != nil {
 		return err
 	}
-
-		addrs := elm.([]net.Addr)
-
-		switch network {
-		case "tcp", "tcp4", "tcp6":
-			if addr, err := lookupTCPAddr(ip, addrs); err == nil {
-				dialer.LocalAddr = addr
-			} else {
-				return err
-			}
-		case "udp", "udp4", "udp6":
-			if addr, err := lookupUDPAddr(ip, addrs); err == nil {
-				dialer.LocalAddr = addr
-			} else {
-				return err
-			}
-		}
-
-		return nil
-	}
 }