feat: add support for RtoMin lock

route.go

@@ -82,6 +82,7 @@ type Route struct {
 	InitCwnd         int
 	Features         int
 	RtoMin           int
+	RtoMinLock       bool
 	InitRwnd         int
 	QuickACK         int
 	Congctl          string

route_linux.go

@@ -1138,6 +1138,10 @@ func (h *Handle) prepareRouteReq(route *Route, req *nl.NetlinkRequest, msg *nl.R
 	if route.RtoMin > 0 {
 		b := nl.Uint32Attr(uint32(route.RtoMin))
 		metrics = append(metrics, nl.NewRtAttr(unix.RTAX_RTO_MIN, b))
+		if route.RtoMinLock {
+			b := nl.Uint32Attr(uint32(1 << unix.RTAX_RTO_MIN))
+			metrics = append(metrics, nl.NewRtAttr(unix.RTAX_LOCK, b))
+		}
 	}
 	if route.InitRwnd > 0 {
 		b := nl.Uint32Attr(uint32(route.InitRwnd))
@@ -1464,6 +1468,7 @@ func deserializeRoute(m []byte) (Route, error) {
 					route.MTU = int(native.Uint32(metric.Value[0:4]))
 				case unix.RTAX_LOCK:
 					route.MTULock = native.Uint32(metric.Value[0:4]) == uint32(1<<unix.RTAX_MTU)
+					route.RtoMinLock = native.Uint32(metric.Value[0:4]) == uint32(1<<unix.RTAX_RTO_MIN)
 				case unix.RTAX_WINDOW:
 					route.Window = int(native.Uint32(metric.Value[0:4]))
 				case unix.RTAX_RTT:

route_test.go

@@ -2336,6 +2336,64 @@ func TestMTULockRouteAddDel(t *testing.T) {
 	}
 }
 
+func TestRtoMinLockRouteAddDel(t *testing.T) {
+	_, err := RouteList(nil, FAMILY_V4)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	tearDown := setUpNetlinkTest(t)
+	defer tearDown()
+
+	// get loopback interface
+	link, err := LinkByName("lo")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// bring the interface up
+	if err := LinkSetUp(link); err != nil {
+		t.Fatal(err)
+	}
+
+	// add a gateway route
+	dst := &net.IPNet{
+		IP:   net.IPv4(192, 168, 0, 0),
+		Mask: net.CIDRMask(24, 32),
+	}
+
+	route := Route{LinkIndex: link.Attrs().Index, Dst: dst, RtoMin: 40, RtoMinLock: true}
+	if err := RouteAdd(&route); err != nil {
+		t.Fatal(err)
+	}
+	routes, err := RouteList(link, FAMILY_V4)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(routes) != 1 {
+		t.Fatal("Route not added properly")
+	}
+
+	if route.RtoMin != routes[0].RtoMin {
+		t.Fatal("Route RtoMin not set properly")
+	}
+
+	if route.RtoMinLock != routes[0].RtoMinLock {
+		t.Fatal("Route RtoMin lock not set properly")
+	}
+
+	if err := RouteDel(&route); err != nil {
+		t.Fatal(err)
+	}
+	routes, err = RouteList(link, FAMILY_V4)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(routes) != 0 {
+		t.Fatal("Route not removed properly")
+	}
+}
+
 func TestRouteViaAddDel(t *testing.T) {
 	minKernelRequired(t, 5, 4)
 	tearDown := setUpNetlinkTest(t)