Feature: bind socket to interface by native API on Windows (#2662)

component/dhcp/conn.go

@@ -14,5 +14,15 @@ func ListenDHCPClient(ctx context.Context, ifaceName string) (net.PacketConn, er
 		listenAddr = "255.255.255.255:68"
 	}
 
-	return dialer.ListenPacket(ctx, "udp4", listenAddr, dialer.WithInterface(ifaceName), dialer.WithAddrReuse(true))
+	options := []dialer.Option{
+		dialer.WithInterface(ifaceName),
+		dialer.WithAddrReuse(true),
+	}
+
+	// fallback bind on windows, because syscall bind can not receive broadcast
+	if runtime.GOOS == "windows" {
+		options = append(options, dialer.WithFallbackBind(true))
+	}
+
+	return dialer.ListenPacket(ctx, "udp4", listenAddr, options...)
 }

component/dialer/bind_others.go

@@ -1,57 +1,12 @@
-//go:build !linux && !darwin
+//go:build !linux && !darwin && !windows
 
 package dialer
 
 import (
 	"net"
 	"strconv"
-	"strings"
-
-	"github.com/Dreamacro/clash/component/iface"
 )
 
-func lookupLocalAddr(ifaceName string, network string, destination net.IP, port int) (net.Addr, error) {
-	ifaceObj, err := iface.ResolveInterface(ifaceName)
-	if err != nil {
-		return nil, err
-	}
-
-	var addr *net.IPNet
-	switch network {
-	case "udp4", "tcp4":
-		addr, err = ifaceObj.PickIPv4Addr(destination)
-	case "tcp6", "udp6":
-		addr, err = ifaceObj.PickIPv6Addr(destination)
-	default:
-		if destination != nil {
-			if destination.To4() != nil {
-				addr, err = ifaceObj.PickIPv4Addr(destination)
-			} else {
-				addr, err = ifaceObj.PickIPv6Addr(destination)
-			}
-		} else {
-			addr, err = ifaceObj.PickIPv4Addr(destination)
-		}
-	}
-	if err != nil {
-		return nil, err
-	}
-
-	if strings.HasPrefix(network, "tcp") {
-		return &net.TCPAddr{
-			IP:   addr.IP,
-			Port: port,
-		}, nil
-	} else if strings.HasPrefix(network, "udp") {
-		return &net.UDPAddr{
-			IP:   addr.IP,
-			Port: port,
-		}, nil
-	}
-
-	return nil, iface.ErrAddrNotFound
-}
-
 func bindIfaceToDialer(ifaceName string, dialer *net.Dialer, network string, destination net.IP) error {
 	if !destination.IsGlobalUnicast() {
 		return nil

component/dialer/bind_windows.go

@@ -0,0 +1,98 @@
+package dialer
+
+import (
+	"encoding/binary"
+	"net"
+	"strings"
+	"syscall"
+	"unsafe"
+
+	"github.com/Dreamacro/clash/component/iface"
+
+	"golang.org/x/sys/windows"
+)
+
+const (
+	IP_UNICAST_IF   = 31
+	IPV6_UNICAST_IF = 31
+)
+
+type controlFn = func(network, address string, c syscall.RawConn) error
+
+func bindControl(ifaceIdx int, chain controlFn) controlFn {
+	return func(network, address string, c syscall.RawConn) (err error) {
+		defer func() {
+			if err == nil && chain != nil {
+				err = chain(network, address, c)
+			}
+		}()
+
+		ipStr, _, err := net.SplitHostPort(address)
+		if err == nil {
+			ip := net.ParseIP(ipStr)
+			if ip != nil && !ip.IsGlobalUnicast() {
+				return
+			}
+		}
+
+		var innerErr error
+		err = c.Control(func(fd uintptr) {
+			if ipStr == "" && strings.HasPrefix(network, "udp") {
+				// When listening udp ":0", we should bind socket to interface4 and interface6 at the same time
+				// and ignore the error of bind6
+				_ = bindSocketToInterface6(windows.Handle(fd), ifaceIdx)
+				innerErr = bindSocketToInterface4(windows.Handle(fd), ifaceIdx)
+				return
+			}
+			switch network {
+			case "tcp4", "udp4":
+				innerErr = bindSocketToInterface4(windows.Handle(fd), ifaceIdx)
+			case "tcp6", "udp6":
+				innerErr = bindSocketToInterface6(windows.Handle(fd), ifaceIdx)
+			}
+		})
+
+		if innerErr != nil {
+			err = innerErr
+		}
+
+		return
+	}
+}
+
+func bindSocketToInterface4(handle windows.Handle, ifaceIdx int) error {
+	// MSDN says for IPv4 this needs to be in net byte order, so that it's like an IP address with leading zeros.
+	// Ref: https://learn.microsoft.com/en-us/windows/win32/winsock/ipproto-ip-socket-options
+	var bytes [4]byte
+	binary.BigEndian.PutUint32(bytes[:], uint32(ifaceIdx))
+	index := *(*uint32)(unsafe.Pointer(&bytes[0]))
+	err := windows.SetsockoptInt(handle, windows.IPPROTO_IP, IP_UNICAST_IF, int(index))
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func bindSocketToInterface6(handle windows.Handle, ifaceIdx int) error {
+	return windows.SetsockoptInt(handle, windows.IPPROTO_IPV6, IPV6_UNICAST_IF, ifaceIdx)
+}
+
+func bindIfaceToDialer(ifaceName string, dialer *net.Dialer, _ string, _ net.IP) error {
+	ifaceObj, err := iface.ResolveInterface(ifaceName)
+	if err != nil {
+		return err
+	}
+
+	dialer.Control = bindControl(ifaceObj.Index, dialer.Control)
+	return nil
+}
+
+func bindIfaceToListenConfig(ifaceName string, lc *net.ListenConfig, _, address string) (string, error) {
+	ifaceObj, err := iface.ResolveInterface(ifaceName)
+	if err != nil {
+		return "", err
+	}
+
+	lc.Control = bindControl(ifaceObj.Index, lc.Control)
+	return address, nil
+}

component/dialer/dialer.go

@@ -51,7 +51,15 @@ func ListenPacket(ctx context.Context, network, address string, options ...Optio
 
 	lc := &net.ListenConfig{}
 	if cfg.interfaceName != "" {
-		addr, err := bindIfaceToListenConfig(cfg.interfaceName, lc, network, address)
+		var (
+			addr string
+			err  error
+		)
+		if cfg.fallbackBind {
+			addr, err = fallbackBindIfaceToListenConfig(cfg.interfaceName, lc, network, address)
+		} else {
+			addr, err = bindIfaceToListenConfig(cfg.interfaceName, lc, network, address)
+		}
 		if err != nil {
 			return nil, err
 		}
@@ -83,10 +91,16 @@ func dialContext(ctx context.Context, network string, destination net.IP, port s
 
 	dialer := &net.Dialer{}
 	if opt.interfaceName != "" {
+		if opt.fallbackBind {
+			if err := fallbackBindIfaceToDialer(opt.interfaceName, dialer, network, destination); err != nil {
+				return nil, err
+			}
+		} else {
 			if err := bindIfaceToDialer(opt.interfaceName, dialer, network, destination); err != nil {
 				return nil, err
 			}
 		}
+	}
 	if opt.routingMark != 0 {
 		bindMarkToDialer(opt.routingMark, dialer, network, destination)
 	}

component/dialer/fallbackbind.go

@@ -0,0 +1,90 @@
+package dialer
+
+import (
+	"net"
+	"strconv"
+	"strings"
+
+	"github.com/Dreamacro/clash/component/iface"
+)
+
+func lookupLocalAddr(ifaceName string, network string, destination net.IP, port int) (net.Addr, error) {
+	ifaceObj, err := iface.ResolveInterface(ifaceName)
+	if err != nil {
+		return nil, err
+	}
+
+	var addr *net.IPNet
+	switch network {
+	case "udp4", "tcp4":
+		addr, err = ifaceObj.PickIPv4Addr(destination)
+	case "tcp6", "udp6":
+		addr, err = ifaceObj.PickIPv6Addr(destination)
+	default:
+		if destination != nil {
+			if destination.To4() != nil {
+				addr, err = ifaceObj.PickIPv4Addr(destination)
+			} else {
+				addr, err = ifaceObj.PickIPv6Addr(destination)
+			}
+		} else {
+			addr, err = ifaceObj.PickIPv4Addr(destination)
+		}
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	if strings.HasPrefix(network, "tcp") {
+		return &net.TCPAddr{
+			IP:   addr.IP,
+			Port: port,
+		}, nil
+	} else if strings.HasPrefix(network, "udp") {
+		return &net.UDPAddr{
+			IP:   addr.IP,
+			Port: port,
+		}, nil
+	}
+
+	return nil, iface.ErrAddrNotFound
+}
+
+func fallbackBindIfaceToDialer(ifaceName string, dialer *net.Dialer, network string, destination net.IP) error {
+	if !destination.IsGlobalUnicast() {
+		return nil
+	}
+
+	local := uint64(0)
+	if dialer.LocalAddr != nil {
+		_, port, err := net.SplitHostPort(dialer.LocalAddr.String())
+		if err == nil {
+			local, _ = strconv.ParseUint(port, 10, 16)
+		}
+	}
+
+	addr, err := lookupLocalAddr(ifaceName, network, destination, int(local))
+	if err != nil {
+		return err
+	}
+
+	dialer.LocalAddr = addr
+
+	return nil
+}
+
+func fallbackBindIfaceToListenConfig(ifaceName string, _ *net.ListenConfig, network, address string) (string, error) {
+	_, port, err := net.SplitHostPort(address)
+	if err != nil {
+		port = "0"
+	}
+
+	local, _ := strconv.ParseUint(port, 10, 16)
+
+	addr, err := lookupLocalAddr(ifaceName, network, nil, int(local))
+	if err != nil {
+		return "", err
+	}
+
+	return addr.String(), nil
+}

component/dialer/options.go

@@ -10,6 +10,7 @@ var (
 
 type option struct {
 	interfaceName string
+	fallbackBind  bool
 	addrReuse     bool
 	routingMark   int
 }
@@ -22,6 +23,12 @@ func WithInterface(name string) Option {
 	}
 }
 
+func WithFallbackBind(fallback bool) Option {
+	return func(opt *option) {
+		opt.fallbackBind = fallback
+	}
+}
+
 func WithAddrReuse(reuse bool) Option {
 	return func(opt *option) {
 		opt.addrReuse = reuse