Add tun.UpdateRouteOptions

tun.go

@@ -28,6 +28,7 @@ type Tun interface {
 	Name() (string, error)
 	Start() error
 	Close() error
+	UpdateRouteOptions(tunOptions Options) error
 }
 
 type WinTun interface {

tun_darwin.go

@@ -29,7 +29,7 @@ type NativeTun struct {
 	options      Options
 	inet4Address [4]byte
 	inet6Address [16]byte
-	routerSet    bool
+	routeSet     bool
 }
 
 func (t *NativeTun) Name() (string, error) {
@@ -258,9 +258,17 @@ func configure(tunFd int, ifIndex int, name string, options Options) error {
 	return nil
 }
 
+func (t *NativeTun) UpdateRouteOptions(tunOptions Options) error {
+	err := t.unsetRoutes()
+	if err != nil {
+		return err
+	}
+	t.options = tunOptions
+	return t.setRoutes()
+}
+
 func (t *NativeTun) setRoutes() error {
 	if t.options.AutoRoute && t.options.FileDescriptor == 0 {
-
 		routeRanges, err := t.options.BuildAutoRouteRanges(false)
 		if err != nil {
 			return err
@@ -298,13 +306,13 @@ func (t *NativeTun) setRoutes() error {
 			}
 		}
 		flushDNSCache()
-		t.routerSet = true
+		t.routeSet = true
 	}
 	return nil
 }
 
 func (t *NativeTun) unsetRoutes() error {
-	if !t.routerSet {
+	if !t.routeSet {
 		return nil
 	}
 	routeRanges, err := t.options.BuildAutoRouteRanges(false)

tun_linux.go

@@ -495,6 +495,25 @@ func prefixToIPNet(prefix netip.Prefix) *net.IPNet {
 	}
 }
 
+func (t *NativeTun) UpdateRouteOptions(tunOptions Options) error {
+	if t.options.FileDescriptor > 0 {
+		return nil
+	} else if !t.options.AutoRoute {
+		t.options = tunOptions
+		return nil
+	}
+	tunLink, err := netlink.LinkByName(t.options.Name)
+	if err != nil {
+		return err
+	}
+	err = t.unsetRoute0(tunLink)
+	if err != nil {
+		return err
+	}
+	t.options = tunOptions
+	return t.setRoute(tunLink)
+}
+
 func (t *NativeTun) routes(tunLink netlink.Link) ([]netlink.Route, error) {
 	routeRanges, err := t.options.BuildAutoRouteRanges(false)
 	if err != nil {

tun_windows.go

@@ -178,9 +178,9 @@ func (t *NativeTun) Start() error {
 		} else {
 			err = luid.AddRoute(routeRange, gateway6, 0)
 		}
-	}
-	if err != nil {
-		return err
+		if err != nil {
+			return err
+		}
 	}
 	err = windnsapi.FlushResolverCache()
 	if err != nil {
@@ -545,6 +545,38 @@ func (t *NativeTun) Close() error {
 	return err
 }
 
+func (t *NativeTun) UpdateRouteOptions(tunOptions Options) error {
+	t.options = tunOptions
+	if !t.options.AutoRoute {
+		return nil
+	}
+	gateway4, gateway6 := t.options.Inet4GatewayAddr(), t.options.Inet6GatewayAddr()
+	routeRanges, err := t.options.BuildAutoRouteRanges(false)
+	if err != nil {
+		return err
+	}
+	luid := winipcfg.LUID(t.adapter.LUID())
+	err = luid.FlushRoutes(windows.AF_UNSPEC)
+	if err != nil {
+		return err
+	}
+	for _, routeRange := range routeRanges {
+		if routeRange.Addr().Is4() {
+			err = luid.AddRoute(routeRange, gateway4, 0)
+		} else {
+			err = luid.AddRoute(routeRange, gateway6, 0)
+		}
+		if err != nil {
+			return err
+		}
+	}
+	err = windnsapi.FlushResolverCache()
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
 func generateGUIDByDeviceName(name string) *windows.GUID {
 	hash := md5.New()
 	hash.Write([]byte("wintun"))