platform: add and use nm_platform_ip_route_normalize()

Adding a route to kernel may coerce/mangle some properties. Add a function
nm_platform_ip_route_normalize() to simulate these changes.

src/platform/nm-fake-platform.c

@@ -1230,24 +1230,17 @@ ip_route_add (NMPlatform *platform,
 	                        ? NMP_OBJECT_TYPE_IP4_ROUTE
 	                        : NMP_OBJECT_TYPE_IP6_ROUTE,
 	                      (const NMPlatformObject *) route);
-	r = &obj->ip_route;
+	r = NMP_OBJECT_CAST_IP_ROUTE (obj);
+	nm_platform_ip_route_normalize (addr_family, r);
 
 	switch (addr_family) {
 	case AF_INET:
 		r4 = NMP_OBJECT_CAST_IP4_ROUTE (obj);
-		r4->network = nm_utils_ip4_address_clear_host_address (r4->network, r4->plen);
-		r4->rt_source = nmp_utils_ip_config_source_round_trip_rtprot (r4->rt_source),
-		r4->scope_inv = nm_platform_route_scope_inv (!r4->gateway
-		                                             ? RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
 		if (r4->gateway)
 			has_gateway = TRUE;
 		break;
 	case AF_INET6:
 		r6 = NMP_OBJECT_CAST_IP6_ROUTE (obj);
-		nm_utils_ip6_address_clear_host_address (&r6->network, &r6->network, r6->plen);
-		r6->rt_source = nmp_utils_ip_config_source_round_trip_rtprot (r6->rt_source),
-		r6->metric = nm_utils_ip6_route_metric_normalize (r6->metric);
-		nm_utils_ip6_address_clear_host_address (&r6->src, &r6->src, r6->src_plen);
 		if (!IN6_IS_ADDR_UNSPECIFIED (&r6->gateway))
 			has_gateway = TRUE;
 		break;

src/platform/nm-linux-platform.c

@@ -5836,30 +5836,20 @@ ip_route_add (NMPlatform *platform,
 {
 	nm_auto_nlmsg struct nl_msg *nlmsg = NULL;
 	NMPObject obj;
-	NMPlatformIP4Route *r4;
-	NMPlatformIP6Route *r6;
 
 	switch (addr_family) {
 	case AF_INET:
 		nmp_object_stackinit (&obj, NMP_OBJECT_TYPE_IP4_ROUTE, (const NMPlatformObject *) route);
-		r4 = NMP_OBJECT_CAST_IP4_ROUTE (&obj);
-		r4->network = nm_utils_ip4_address_clear_host_address (r4->network, r4->plen);
-		r4->rt_source = nmp_utils_ip_config_source_round_trip_rtprot (r4->rt_source),
-		r4->scope_inv = nm_platform_route_scope_inv (!r4->gateway
-		                                             ? RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
 		break;
 	case AF_INET6:
 		nmp_object_stackinit (&obj, NMP_OBJECT_TYPE_IP6_ROUTE, (const NMPlatformObject *) route);
-		r6 = NMP_OBJECT_CAST_IP6_ROUTE (&obj);
-		nm_utils_ip6_address_clear_host_address (&r6->network, &r6->network, r6->plen);
-		r6->rt_source = nmp_utils_ip_config_source_round_trip_rtprot (r6->rt_source),
-		r6->metric = nm_utils_ip6_route_metric_normalize (r6->metric);
-		nm_utils_ip6_address_clear_host_address (&r6->src, &r6->src, r6->src_plen);
 		break;
 	default:
 		nm_assert_not_reached ();
 	}
 
+	nm_platform_ip_route_normalize (addr_family, NMP_OBJECT_CAST_IP_ROUTE (&obj));
+
 	nlmsg = _nl_msg_new_route (RTM_NEWROUTE, flags, &obj);
 	if (!nlmsg)
 		g_return_val_if_reached (FALSE);

src/platform/nm-platform.c

@@ -3482,6 +3482,43 @@ nm_platform_ip_address_flush (NMPlatform *self,
 
 /*****************************************************************************/
 
+/**
+ * nm_platform_ip_route_normalize:
+ * @addr_family: AF_INET or AF_INET6
+ * @route: an NMPlatformIP4Route or NMPlatformIP6Route instance, depending on @addr_family.
+ *
+ * Adding a route to kernel via nm_platform_ip_route_add() will normalize/coerce some
+ * properties of the route. This function modifies (normalizes) the route like it
+ * would be done by adding the route in kernel.
+ */
+void
+nm_platform_ip_route_normalize (int addr_family,
+                                NMPlatformIPRoute *route)
+{
+	NMPlatformIP4Route *r4;
+	NMPlatformIP6Route *r6;
+
+	switch (addr_family) {
+	case AF_INET:
+		r4 = (NMPlatformIP4Route *) route;
+		r4->network = nm_utils_ip4_address_clear_host_address (r4->network, r4->plen);
+		r4->rt_source = nmp_utils_ip_config_source_round_trip_rtprot (r4->rt_source);
+		r4->scope_inv = nm_platform_route_scope_inv (!r4->gateway
+		                                             ? RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
+		break;
+	case AF_INET6:
+		r6 = (NMPlatformIP6Route *) route;
+		nm_utils_ip6_address_clear_host_address (&r6->network, &r6->network, r6->plen);
+		r6->rt_source = nmp_utils_ip_config_source_round_trip_rtprot (r6->rt_source),
+		r6->metric = nm_utils_ip6_route_metric_normalize (r6->metric);
+		nm_utils_ip6_address_clear_host_address (&r6->src, &r6->src, r6->src_plen);
+		break;
+	default:
+		nm_assert_not_reached ();
+		break;
+	}
+}
+
 static gboolean
 _ip_route_add (NMPlatform *self,
                NMPNlmFlags flags,

src/platform/nm-platform.h

@@ -1117,6 +1117,9 @@ gboolean nm_platform_ip_address_flush (NMPlatform *self,
                                        int addr_family,
                                        int ifindex);
 
+void nm_platform_ip_route_normalize (int addr_family,
+                                     NMPlatformIPRoute *route);
+
 gboolean nm_platform_ip_route_add (NMPlatform *self,
                                    NMPNlmFlags flags,
                                    const NMPObject *route);