core: add dependent local routes configured by kernel

Pre-generate routes in the local table that are configured
by kernel when an ip-address is assigned to an interface.

This helps NM taking into account routes that are not to be deleted
when a connection is reapplied (or deactivated) on an interface instead of only
ignoring (when pruning) IPv6 routes having metric 0 and routes belonging
to the local table having 'kernel' as proto.

https://bugzilla.redhat.com/show_bug.cgi?id=1821787

src/nm-ip4-config.c

@@ -671,6 +671,28 @@ nm_ip4_config_update_routes_metric (NMIP4Config *self, gint64 metric)
 	g_object_thaw_notify (G_OBJECT (self));
 }
 
+static void
+_add_local_route_from_addr4 (NMIP4Config *self,
+                            const NMPlatformIP4Address *addr,
+                            int ifindex)
+{
+	nm_auto_nmpobj NMPObject *r = NULL;
+	NMPlatformIP4Route *route;
+
+	r = nmp_object_new (NMP_OBJECT_TYPE_IP4_ROUTE, NULL);
+	route = NMP_OBJECT_CAST_IP4_ROUTE (r);
+	route->ifindex = ifindex;
+	route->rt_source = NM_IP_CONFIG_SOURCE_KERNEL;
+	route->network = addr->address;
+	route->plen = 32;
+	route->pref_src = addr->address;
+	route->table_coerced = nm_platform_route_table_coerce (RT_TABLE_LOCAL);
+	route->type_coerced = nm_platform_route_type_coerce (RTN_LOCAL);
+	route->scope_inv = nm_platform_route_scope_inv (RT_SCOPE_HOST);
+
+	_add_route (self, r, NULL, NULL);
+}
+
 void
 nm_ip4_config_add_dependent_routes (NMIP4Config *self,
                                     guint32 route_table,
@@ -707,6 +729,8 @@ nm_ip4_config_add_dependent_routes (NMIP4Config *self,
 		if (my_addr->external)
 			continue;
 
+		_add_local_route_from_addr4 (self, my_addr, ifindex);
+
 		if (_ipv4_is_zeronet (network)) {
 			/* Kernel doesn't add device-routes for destinations that
 			 * start with 0.x.y.z. Skip them. */

src/nm-ip6-config.c

@@ -474,6 +474,24 @@ _add_multicast_route6 (NMIP6Config *self, int ifindex)
 	_add_route (self, r, NULL, NULL);
 }
 
+static void
+_add_local_route_from_addr6 (NMIP6Config *self, const NMPlatformIP6Address *addr, int ifindex)
+{
+	nm_auto_nmpobj NMPObject *r = NULL;
+	NMPlatformIP6Route *route;
+
+	r = nmp_object_new (NMP_OBJECT_TYPE_IP6_ROUTE, NULL);
+	route = NMP_OBJECT_CAST_IP6_ROUTE (r);
+	route->ifindex = ifindex;
+	route->network = addr->address;
+	route->plen = 128;
+	route->table_coerced = nm_platform_route_table_coerce (RT_TABLE_LOCAL);
+	route->type_coerced = nm_platform_route_type_coerce (RTN_LOCAL);
+	route->metric = 0;
+
+	_add_route (self, r, NULL, NULL);
+}
+
 void
 nm_ip6_config_add_dependent_routes (NMIP6Config *self,
                                     guint32 route_table,
@@ -504,6 +522,10 @@ nm_ip6_config_add_dependent_routes (NMIP6Config *self,
 
 		if (my_addr->external)
 			continue;
+
+		/* Pre-generate local route added by kernel */
+		_add_local_route_from_addr6 (self, my_addr, ifindex);
+
 		if (NM_FLAGS_HAS (my_addr->n_ifa_flags, IFA_F_NOPREFIXROUTE))
 			continue;
 		if (my_addr->plen == 0)

src/platform/nm-platform.c

@@ -4230,18 +4230,9 @@ nm_platform_ip_route_get_prune_list (NMPlatform *self,
 		} else if (route_table_sync == NM_IP_ROUTE_TABLE_SYNC_MODE_MAIN) {
 			if (!nm_platform_route_table_is_main (NMP_OBJECT_CAST_IP_ROUTE (obj)->table_coerced))
 				continue;
-		} else {
+		} else
 			nm_assert (route_table_sync == NM_IP_ROUTE_TABLE_SYNC_MODE_ALL);
 
-			/* IPv6 routes having metric 0 and routes having rt_source == NM_IP_CONFIG_SOURCE_RTPROT_KERNEL
-			 * are entirely managed by kernel, let's not touch them */
-			if (addr_family == AF_INET6 && NMP_OBJECT_CAST_IP6_ROUTE (obj)->metric == 0)
-				continue;
-			if (   nm_platform_route_table_uncoerce (NMP_OBJECT_CAST_IP_ROUTE (obj)->table_coerced, TRUE) == RT_TABLE_LOCAL
-			    && NMP_OBJECT_CAST_IP_ROUTE (obj)->rt_source == NM_IP_CONFIG_SOURCE_RTPROT_KERNEL)
-				continue;
-		}
-
 		g_ptr_array_add (routes_prune, (gpointer) nmp_object_ref (obj));
 	}