Add tun inbound for windows

common/dialer/auto_other.go

@@ -1,4 +1,4 @@
-//go:build !linux
+//go:build !linux && !windows
 
 package dialer
 

common/dialer/auto_windows.go

@@ -0,0 +1,68 @@
+package dialer
+
+import (
+	"encoding/binary"
+	"net"
+	"net/netip"
+	"syscall"
+	"unsafe"
+
+	"github.com/sagernet/sing-box/adapter"
+	"github.com/sagernet/sing/common/control"
+	E "github.com/sagernet/sing/common/exceptions"
+
+	"golang.org/x/sys/windows"
+)
+
+const (
+	IP_UNICAST_IF   = 31
+	IPV6_UNICAST_IF = 31
+)
+
+func bind4(handle windows.Handle, ifaceIdx int) error {
+	var bytes [4]byte
+	binary.BigEndian.PutUint32(bytes[:], uint32(ifaceIdx))
+	idx := *(*uint32)(unsafe.Pointer(&bytes[0]))
+	return windows.SetsockoptInt(handle, windows.IPPROTO_IP, IP_UNICAST_IF, int(idx))
+}
+
+func bind6(handle windows.Handle, ifaceIdx int) error {
+	return windows.SetsockoptInt(handle, windows.IPPROTO_IPV6, IPV6_UNICAST_IF, int(ifaceIdx))
+}
+
+func BindToInterface(router adapter.Router) control.Func {
+	return func(network, address string, conn syscall.RawConn) error {
+		interfaceName := router.DefaultInterfaceName()
+		if interfaceName == "" {
+			return nil
+		}
+		ipStr, _, err := net.SplitHostPort(address)
+		if err == nil {
+			if ip, err := netip.ParseAddr(ipStr); err == nil && !ip.IsGlobalUnicast() {
+				return err
+			}
+		}
+		var innerErr error
+		err = conn.Control(func(fd uintptr) {
+			handle := windows.Handle(fd)
+			// handle ip empty, e.g. net.Listen("udp", ":0")
+			if ipStr == "" {
+				innerErr = bind4(handle, router.DefaultInterfaceIndex())
+				if innerErr != nil {
+					return
+				}
+				// try bind ipv6, if failed, ignore. it's a workaround for windows disable interface ipv6
+				bind6(handle, router.DefaultInterfaceIndex())
+				return
+			}
+
+			switch network {
+			case "tcp4", "udp4", "ip4":
+				innerErr = bind4(handle, router.DefaultInterfaceIndex())
+			case "tcp6", "udp6":
+				innerErr = bind6(handle, router.DefaultInterfaceIndex())
+			}
+		})
+		return E.Errors(innerErr, err)
+	}
+}