core: fix treating route metric zero of IPv6 routes specialth/platform-ipv6-route-metric-zero

Userspace cannot add IPv6 routes with metric 0. Trying to do that, will
be coerced by kernel to route metric 1024. For IPv4 this is different,
and metric zero is commonly allowed.

However, kernel itself can add IPv6 routes with metric zero:

  # ip -6 route show table local
  local fe80::2029:c7ff:fec9:698a dev v proto kernel metric 0 pref medium

That means, we must not treat route metric zero special for most cases.
Only, when we want to add routes (based on user configuration), we must
coerce a route metric of zero to 1024.

9 files changed, 66 insertions, 64 deletions

diff --git a/src/dhcp/nm-dhcp-utils.c b/src/dhcp/nm-dhcp-utils.c
index d8e5a65328..1c305238fd 100644
--- a/src/dhcp/nm-dhcp-utils.c
+++ b/src/dhcp/nm-dhcp-utils.c
@@ -440,10 +440,10 @@ nm_dhcp_utils_ip4_config_from_options (NMDedupMultiIndex *multi_idx,
 
 	if (gateway_has) {
 		const NMPlatformIP4Route r = {
-			.rt_source = NM_IP_CONFIG_SOURCE_DHCP,
-			.gateway = gateway,
+			.rt_source     = NM_IP_CONFIG_SOURCE_DHCP,
+			.gateway       = gateway,
 			.table_coerced = nm_platform_route_table_coerce (route_table),
-			.metric = route_metric,
+			.metric        = route_metric,
 		};
 
 		nm_ip4_config_add_route (ip4_config, &r, NULL);
diff --git a/src/nm-core-utils.h b/src/nm-core-utils.h
index 1b911894c9..cb6b06208e 100644
--- a/src/nm-core-utils.h
+++ b/src/nm-core-utils.h
@@ -156,8 +156,13 @@ double nm_utils_exp10 (gint16 e);
  * nm_utils_ip6_route_metric_normalize:
  * @metric: the route metric
  *
- * For IPv6 route, kernel treats the value 0 as IP6_RT_PRIO_USER (1024).
- * Thus, when comparing metric (values), we want to treat zero as NM_PLATFORM_ROUTE_METRIC_DEFAULT_IP6.
+ * For IPv6 route, when adding a route via netlink, kernel treats the value 0 as IP6_RT_PRIO_USER (1024).
+ * So, user space cannot add routes with such a metric, and 0 gets "normalized"
+ * to NM_PLATFORM_ROUTE_METRIC_DEFAULT_IP6.
+ *
+ * Note that kernel itself can add IPv6 routes with metric zero. Also, you can delete
+ * them, but mostly because with `ip -6 route delete ... metric 0` the 0 acts as a wildcard
+ * and kills the first matching route.
  *
  * Returns: @metric, if @metric is not zero, otherwise 1024.
  */
@@ -174,9 +179,8 @@ nm_utils_ip_route_metric_normalize (int addr_family, guint32 metric)
 }
 
 static inline guint32
-nm_utils_ip_route_metric_penalize (int addr_family, guint32 metric, guint32 penalty)
+nm_utils_ip_route_metric_penalize (guint32 metric, guint32 penalty)
 {
-	metric = nm_utils_ip_route_metric_normalize (addr_family, metric);
 	if (metric < G_MAXUINT32 - penalty)
 		return metric + penalty;
 	return G_MAXUINT32;
diff --git a/src/nm-ip4-config.c b/src/nm-ip4-config.c
index 62b41478f4..8f3ef1f583 100644
--- a/src/nm-ip4-config.c
+++ b/src/nm-ip4-config.c
@@ -393,10 +393,6 @@ nm_ip_config_iter_ip4_route_init (NMDedupMultiIter *ipconf_iter, const NMIP4Conf
 const NMPObject *
 _nm_ip_config_best_default_route_find_better (const NMPObject *obj_cur, const NMPObject *obj_cmp)
 {
-	int addr_family;
-	int c;
-	guint metric_cur, metric_cmp;
-
 	nm_assert (   !obj_cur
 	           || NM_IN_SET (NMP_OBJECT_GET_TYPE (obj_cur), NMP_OBJECT_TYPE_IP4_ROUTE, NMP_OBJECT_TYPE_IP6_ROUTE));
 	nm_assert (   !obj_cmp
@@ -410,17 +406,20 @@ _nm_ip_config_best_default_route_find_better (const NMPObject *obj_cur, const NM
 	 * @obj_cmp is also a default route and returns the best of both. */
 	if (   obj_cmp
 	    && nm_ip_config_best_default_route_is (obj_cmp)) {
+		guint32 metric_cur, metric_cmp;
+
 		if (!obj_cur)
 			return obj_cmp;
 
-		addr_family = NMP_OBJECT_GET_CLASS (obj_cmp)->addr_family;
-		metric_cur = nm_utils_ip_route_metric_normalize (addr_family, NMP_OBJECT_CAST_IP_ROUTE (obj_cur)->metric);
-		metric_cmp = nm_utils_ip_route_metric_normalize (addr_family, NMP_OBJECT_CAST_IP_ROUTE (obj_cmp)->metric);
+		metric_cur = NMP_OBJECT_CAST_IP_ROUTE (obj_cur)->metric;
+		metric_cmp = NMP_OBJECT_CAST_IP_ROUTE (obj_cmp)->metric;
 
 		if (metric_cmp < metric_cur)
 			return obj_cmp;
 
 		if (metric_cmp == metric_cur) {
+			int c;
+
 			/* Routes have the same metric. We still want to deterministically
 			 * prefer one or the other. It's important to consistently choose one
 			 * or the other, so that the order doesn't matter how routes are added
@@ -1002,6 +1001,7 @@ nm_ip4_config_merge_setting (NMIP4Config *self,
 	for (i = 0; i < nroutes; i++) {
 		NMIPRoute *s_route = nm_setting_ip_config_get_route (setting, i);
 		NMPlatformIP4Route route;
+		gint64 m;
 
 		if (nm_ip_route_get_family (s_route) != AF_INET) {
 			nm_assert_not_reached ();
@@ -1015,10 +1015,11 @@ nm_ip4_config_merge_setting (NMIP4Config *self,
 		nm_assert (route.plen <= 32);
 
 		nm_ip_route_get_next_hop_binary (s_route, &route.gateway);
-		if (nm_ip_route_get_metric (s_route) == -1)
+		m = nm_ip_route_get_metric (s_route);
+		if (m < 0)
 			route.metric = route_metric;
 		else
-			route.metric = nm_ip_route_get_metric (s_route);
+			route.metric = m;
 		route.rt_source = NM_IP_CONFIG_SOURCE_USER;
 
 		route.network = nm_utils_ip4_address_clear_host_address (route.network, route.plen);
@@ -1141,8 +1142,10 @@ nm_ip4_config_create_setting (const NMIP4Config *self)
 			continue;
 
 		s_route = nm_ip_route_new_binary (AF_INET,
-		                                  &route->network, route->plen,
-		                                  &route->gateway, route->metric,
+		                                  &route->network,
+		                                  route->plen,
+		                                  &route->gateway,
+		                                  route->metric,
 		                                  NULL);
 		nm_setting_ip_config_add_route (s_ip4, s_route);
 		nm_ip_route_unref (s_route);
@@ -1227,7 +1230,7 @@ nm_ip4_config_merge (NMIP4Config *dst,
 				if (default_route_metric_penalty) {
 					NMPlatformIP4Route r = *r_src;
 
-					r.metric = nm_utils_ip_route_metric_penalize (AF_INET, r.metric, default_route_metric_penalty);
+					r.metric = nm_utils_ip_route_metric_penalize (r.metric, default_route_metric_penalty);
 					_add_route (dst, NULL, &r, NULL);
 					continue;
 				}
@@ -1459,7 +1462,7 @@ nm_ip4_config_subtract (NMIP4Config *dst,
 			 * the routes. */
 			o_lookup = nmp_object_stackinit_obj (&o_lookup_copy, o_src);
 			rr = NMP_OBJECT_CAST_IP4_ROUTE (&o_lookup_copy);
-			rr->metric = nm_utils_ip_route_metric_penalize (AF_INET, rr->metric, default_route_metric_penalty);
+			rr->metric = nm_utils_ip_route_metric_penalize (rr->metric, default_route_metric_penalty);
 		} else
 			o_lookup = o_src;
 
@@ -1610,7 +1613,7 @@ _nm_ip4_config_intersect_helper (NMIP4Config *dst,
 			 * the routes. */
 			o_lookup = nmp_object_stackinit_obj (&o_lookup_copy, o_dst);
 			rr = NMP_OBJECT_CAST_IP4_ROUTE (&o_lookup_copy);
-			rr->metric = nm_utils_ip_route_metric_penalize (AF_INET, rr->metric, default_route_metric_penalty);
+			rr->metric = nm_utils_ip_route_metric_penalize (rr->metric, default_route_metric_penalty);
 		} else
 			o_lookup = o_dst;
 
diff --git a/src/nm-ip6-config.c b/src/nm-ip6-config.c
index b60e8057cb..d772d6a255 100644
--- a/src/nm-ip6-config.c
+++ b/src/nm-ip6-config.c
@@ -650,6 +650,7 @@ nm_ip6_config_merge_setting (NMIP6Config *self,
 	for (i = 0; i < nroutes; i++) {
 		NMIPRoute *s_route = nm_setting_ip_config_get_route (setting, i);
 		NMPlatformIP6Route route;
+		gint64 m;
 
 		if (nm_ip_route_get_family (s_route) != AF_INET6) {
 			nm_assert_not_reached ();
@@ -663,10 +664,11 @@ nm_ip6_config_merge_setting (NMIP6Config *self,
 		nm_assert (route.plen <= 128);
 
 		nm_ip_route_get_next_hop_binary (s_route, &route.gateway);
-		if (nm_ip_route_get_metric (s_route) == -1)
+		m = nm_ip_route_get_metric (s_route);
+		if (m < 0)
 			route.metric = route_metric;
 		else
-			route.metric = nm_ip_route_get_metric (s_route);
+			route.metric = nm_utils_ip6_route_metric_normalize (m);
 		route.rt_source = NM_IP_CONFIG_SOURCE_USER;
 
 		nm_utils_ip6_address_clear_host_address (&route.network, &route.network, route.plen);
@@ -797,8 +799,10 @@ nm_ip6_config_create_setting (const NMIP6Config *self)
 			continue;
 
 		s_route = nm_ip_route_new_binary (AF_INET6,
-		                                  &route->network, route->plen,
-		                                  &route->gateway, route->metric,
+		                                  &route->network,
+		                                  route->plen,
+		                                  &route->gateway,
+		                                  route->metric,
 		                                  NULL);
 		nm_setting_ip_config_add_route (s_ip6, s_route);
 		nm_ip_route_unref (s_route);
@@ -882,7 +886,7 @@ nm_ip6_config_merge (NMIP6Config *dst,
 				if (default_route_metric_penalty) {
 					NMPlatformIP6Route r = *r_src;
 
-					r.metric = nm_utils_ip_route_metric_penalize (AF_INET6, r.metric, default_route_metric_penalty);
+					r.metric = nm_utils_ip_route_metric_penalize (r.metric, default_route_metric_penalty);
 					_add_route (dst, NULL, &r, NULL);
 					continue;
 				}
@@ -1052,7 +1056,7 @@ nm_ip6_config_subtract (NMIP6Config *dst,
 			 * the routes. */
 			o_lookup = nmp_object_stackinit_obj (&o_lookup_copy, o_src);
 			rr = NMP_OBJECT_CAST_IP6_ROUTE (&o_lookup_copy);
-			rr->metric = nm_utils_ip_route_metric_penalize (AF_INET6, rr->metric, default_route_metric_penalty);
+			rr->metric = nm_utils_ip_route_metric_penalize (rr->metric, default_route_metric_penalty);
 		} else
 			o_lookup = o_src;
 
@@ -1173,7 +1177,7 @@ _nm_ip6_config_intersect_helper (NMIP6Config *dst,
 			 * the routes. */
 			o_lookup = nmp_object_stackinit_obj (&o_lookup_copy, o_dst);
 			rr = NMP_OBJECT_CAST_IP6_ROUTE (&o_lookup_copy);
-			rr->metric = nm_utils_ip_route_metric_penalize (AF_INET6, rr->metric, default_route_metric_penalty);
+			rr->metric = nm_utils_ip_route_metric_penalize (rr->metric, default_route_metric_penalty);
 		} else
 			o_lookup = o_dst;
 
@@ -2052,8 +2056,8 @@ nm_ip6_config_get_direct_route_for_host (const NMIP6Config *self,
 		if (!nm_utils_ip6_address_same_prefix (host, &item->network, item->plen))
 			continue;
 
-		if (best_route &&
-		    nm_utils_ip6_route_metric_normalize (best_route->metric) <= nm_utils_ip6_route_metric_normalize (item->metric))
+		if (   best_route
+		    && best_route->metric <= item->metric)
 			continue;
 
 		best_route = item;
diff --git a/src/nm-manager.c b/src/nm-manager.c
index c69922648d..286c9ef35b 100644
--- a/src/nm-manager.c
+++ b/src/nm-manager.c
@@ -3044,10 +3044,9 @@ _get_best_connectivity (NMManager *self, int addr_family)
 		gint64 metric;
 
 		r = nm_device_get_best_default_route (dev, addr_family);
-		if (r) {
-			metric = nm_utils_ip_route_metric_normalize (addr_family,
-			                                             NMP_OBJECT_CAST_IP_ROUTE (r)->metric);
-		} else {
+		if (r)
+			metric = NMP_OBJECT_CAST_IP_ROUTE (r)->metric;
+		else {
 			/* if all devices have no default-route, we still include the best
 			 * of all connectivity state of all the devices. */
 			metric = G_MAXINT64;
diff --git a/src/nm-policy.c b/src/nm-policy.c
index 5912b8f257..148f5618ba 100644
--- a/src/nm-policy.c
+++ b/src/nm-policy.c
@@ -442,14 +442,12 @@ get_best_active_connection (NMPolicy *self,
 			 *
 			 * In this case, is it really the best device? Why do we even need the best
 			 * device?? */
-			metric = nm_utils_ip_route_metric_normalize (addr_family,
-			                                             NMP_OBJECT_CAST_IP_ROUTE (r)->metric);
+			metric = NMP_OBJECT_CAST_IP_ROUTE (r)->metric;
 			is_fully_activated = TRUE;
 		} else if (   !fully_activated
 		           && (connection = nm_device_get_applied_connection (device))
 		           && nm_utils_connection_has_default_route (connection, addr_family, NULL)) {
-			metric = nm_utils_ip_route_metric_normalize (addr_family,
-			                                             nm_device_get_route_metric (device, addr_family));
+			metric = nm_device_get_route_metric (device, addr_family);
 			is_fully_activated = FALSE;
 		} else
 			continue;
diff --git a/src/platform/nm-platform.c b/src/platform/nm-platform.c
index 26e1f1e282..880e7b5d27 100644
--- a/src/platform/nm-platform.c
+++ b/src/platform/nm-platform.c
@@ -4571,7 +4571,6 @@ nm_platform_ip_route_normalize (int addr_family,
 		r6->table_coerced = nm_platform_route_table_coerce (nm_platform_route_table_uncoerce (r6->table_coerced, TRUE));
 		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:
@@ -7463,7 +7462,7 @@ nm_platform_ip6_route_hash_update (const NMPlatformIP6Route *obj, NMPlatformIPRo
 		                     nm_platform_route_table_uncoerce (obj->table_coerced, TRUE),
 		                     *nm_utils_ip6_address_clear_host_address (&a1, &obj->network, obj->plen),
 		                     obj->plen,
-		                     nm_utils_ip6_route_metric_normalize (obj->metric),
+		                     obj->metric,
 		                     *nm_utils_ip6_address_clear_host_address (&a2, &obj->src, obj->src_plen),
 		                     obj->src_plen);
 		break;
@@ -7473,7 +7472,7 @@ nm_platform_ip6_route_hash_update (const NMPlatformIP6Route *obj, NMPlatformIPRo
 		                     nm_platform_route_table_uncoerce (obj->table_coerced, TRUE),
 		                     *nm_utils_ip6_address_clear_host_address (&a1, &obj->network, obj->plen),
 		                     obj->plen,
-		                     nm_utils_ip6_route_metric_normalize (obj->metric),
+		                     obj->metric,
 		                     *nm_utils_ip6_address_clear_host_address (&a2, &obj->src, obj->src_plen),
 		                     obj->src_plen,
 		                     /* on top of WEAK_ID: */
@@ -7487,7 +7486,7 @@ nm_platform_ip6_route_hash_update (const NMPlatformIP6Route *obj, NMPlatformIPRo
 		                     obj->ifindex,
 		                     *nm_utils_ip6_address_clear_host_address (&a1, &obj->network, obj->plen),
 		                     obj->plen,
-		                     nm_utils_ip6_route_metric_normalize (obj->metric),
+		                     obj->metric,
 		                     obj->gateway,
 		                     obj->pref_src,
 		                     *nm_utils_ip6_address_clear_host_address (&a2, &obj->src, obj->src_plen),
@@ -7550,7 +7549,7 @@ nm_platform_ip6_route_cmp (const NMPlatformIP6Route *a, const NMPlatformIP6Route
 		               nm_platform_route_table_uncoerce (b->table_coerced, TRUE));
 		NM_CMP_DIRECT_IN6ADDR_SAME_PREFIX (&a->network, &b->network, MIN (a->plen, b->plen));
 		NM_CMP_FIELD (a, b, plen);
-		NM_CMP_DIRECT (nm_utils_ip6_route_metric_normalize (a->metric), nm_utils_ip6_route_metric_normalize (b->metric));
+		NM_CMP_FIELD (a, b, metric);
 		NM_CMP_DIRECT_IN6ADDR_SAME_PREFIX (&a->src, &b->src, MIN (a->src_plen, b->src_plen));
 		NM_CMP_FIELD (a, b, src_plen);
 		if (cmp_type == NM_PLATFORM_IP_ROUTE_CMP_TYPE_ID) {
@@ -7573,10 +7572,7 @@ nm_platform_ip6_route_cmp (const NMPlatformIP6Route *a, const NMPlatformIP6Route
 		else
 			NM_CMP_FIELD_IN6ADDR (a, b, network);
 		NM_CMP_FIELD (a, b, plen);
-		if (cmp_type == NM_PLATFORM_IP_ROUTE_CMP_TYPE_SEMANTICALLY)
-			NM_CMP_DIRECT (nm_utils_ip6_route_metric_normalize (a->metric), nm_utils_ip6_route_metric_normalize (b->metric));
-		else
-			NM_CMP_FIELD (a, b, metric);
+		NM_CMP_FIELD (a, b, metric);
 		NM_CMP_FIELD_IN6ADDR (a, b, gateway);
 		NM_CMP_FIELD_IN6ADDR (a, b, pref_src);
 		if (cmp_type == NM_PLATFORM_IP_ROUTE_CMP_TYPE_SEMANTICALLY) {
@@ -8054,14 +8050,6 @@ nm_platform_netns_push (NMPlatform *self, NMPNetns **netns)
 
 /*****************************************************************************/
 
-static guint32
-_vtr_v4_metric_normalize (guint32 metric)
-{
-	return metric;
-}
-
-/*****************************************************************************/
-
 const _NMPlatformVTableRouteUnion nm_platform_vtable_route = {
 	.v4 = {
 		.is_ip4                         = TRUE,
@@ -8070,7 +8058,6 @@ const _NMPlatformVTableRouteUnion nm_platform_vtable_route = {
 		.sizeof_route                   = sizeof (NMPlatformIP4Route),
 		.route_cmp                      = (int (*) (const NMPlatformIPXRoute *a, const NMPlatformIPXRoute *b, NMPlatformIPRouteCmpType cmp_type)) nm_platform_ip4_route_cmp,
 		.route_to_string                = (const char *(*) (const NMPlatformIPXRoute *route, char *buf, gsize len)) nm_platform_ip4_route_to_string,
-		.metric_normalize               = _vtr_v4_metric_normalize,
 	},
 	.v6 = {
 		.is_ip4                         = FALSE,
@@ -8079,7 +8066,6 @@ const _NMPlatformVTableRouteUnion nm_platform_vtable_route = {
 		.sizeof_route                   = sizeof (NMPlatformIP6Route),
 		.route_cmp                      = (int (*) (const NMPlatformIPXRoute *a, const NMPlatformIPXRoute *b, NMPlatformIPRouteCmpType cmp_type)) nm_platform_ip6_route_cmp,
 		.route_to_string                = (const char *(*) (const NMPlatformIPXRoute *route, char *buf, gsize len)) nm_platform_ip6_route_to_string,
-		.metric_normalize               = nm_utils_ip6_route_metric_normalize,
 	},
 };
 
diff --git a/src/platform/nm-platform.h b/src/platform/nm-platform.h
index 145401d19d..339ef5ba3b 100644
--- a/src/platform/nm-platform.h
+++ b/src/platform/nm-platform.h
@@ -382,7 +382,10 @@ typedef union {
 #define NM_PLATFORM_ROUTE_METRIC_DEFAULT_IP4 0
 
 /* Default value for adding an IPv6 route. This is also what iproute2 does.
- * Adding an IPv6 route with metric 0, kernel translates to IP6_RT_PRIO_USER (1024). */
+ * Adding an IPv6 route with metric 0, kernel translates to IP6_RT_PRIO_USER (1024).
+ *
+ * Note that kernel doesn't allow adding IPv6 routes with metric zero via netlink.
+ * It however can itself add routes with metric zero. */
 #define NM_PLATFORM_ROUTE_METRIC_DEFAULT_IP6 1024
 
 /* For IPv4, kernel adds a device route (subnet routes) with metric 0 when user
@@ -720,7 +723,6 @@ typedef struct {
 	gsize sizeof_route;
 	int (*route_cmp) (const NMPlatformIPXRoute *a, const NMPlatformIPXRoute *b, NMPlatformIPRouteCmpType cmp_type);
 	const char *(*route_to_string) (const NMPlatformIPXRoute *route, char *buf, gsize len);
-	guint32 (*metric_normalize) (guint32 metric);
 } NMPlatformVTableRoute;
 
 typedef union {
diff --git a/src/platform/tests/test-route.c b/src/platform/tests/test-route.c
index b37446e3bf..531c61dbdc 100644
--- a/src/platform/tests/test-route.c
+++ b/src/platform/tests/test-route.c
@@ -319,7 +319,7 @@ test_ip6_route (void)
 	guint8 plen = 64;
 	struct in6_addr gateway, pref_src;
 	/* Choose a high metric so that we hopefully don't conflict. */
-	int metric = 22987;
+	const int metric = 22987;
 	int mss = 1000;
 
 	inet_pton (AF_INET6, "2001:db8:a:b:0:0:0:0", &network);
@@ -365,7 +365,7 @@ test_ip6_route (void)
 	rts[0].ifindex = ifindex;
 	rts[0].gateway = in6addr_any;
 	rts[0].pref_src = in6addr_any;
-	rts[0].metric = nm_utils_ip6_route_metric_normalize (metric);
+	rts[0].metric = metric;
 	rts[0].mss = mss;
 	rts[1].rt_source = nmp_utils_ip_config_source_round_trip_rtprot (NM_IP_CONFIG_SOURCE_USER);
 	rts[1].network = network;
@@ -373,7 +373,7 @@ test_ip6_route (void)
 	rts[1].ifindex = ifindex;
 	rts[1].gateway = gateway;
 	rts[1].pref_src = pref_src;
-	rts[1].metric = nm_utils_ip6_route_metric_normalize (metric);
+	rts[1].metric = metric;
 	rts[1].mss = mss;
 	rts[2].rt_source = nmp_utils_ip_config_source_round_trip_rtprot (NM_IP_CONFIG_SOURCE_USER);
 	rts[2].network = in6addr_any;
@@ -381,7 +381,7 @@ test_ip6_route (void)
 	rts[2].ifindex = ifindex;
 	rts[2].gateway = gateway;
 	rts[2].pref_src = in6addr_any;
-	rts[2].metric = nm_utils_ip6_route_metric_normalize (metric);
+	rts[2].metric = metric;
 	rts[2].mss = mss;
 	g_assert_cmpint (routes->len, ==, 3);
 	nmtst_platform_ip6_routes_equal_aptr ((const NMPObject *const*) routes->pdata, rts, routes->len, TRUE);
@@ -586,7 +586,13 @@ test_ip6_route_get (void)
 
 	NMTST_WAIT_ASSERT (100, {
 		nmtstp_wait_for_signal (NM_PLATFORM_GET, 10);
-		if (nmtstp_ip6_route_get (NM_PLATFORM_GET, ifindex, nmtst_inet6_from_string ("fd01:abcd::"), 64, 0, NULL, 0))
+		if (nmtstp_ip6_route_get (NM_PLATFORM_GET,
+		                          ifindex,
+		                          nmtst_inet6_from_string ("fd01:abcd::"),
+		                          64,
+		                          NM_PLATFORM_ROUTE_METRIC_DEFAULT_IP6,
+		                          NULL,
+		                          0))
 			break;
 	});