zebra: table_id election with the vrf backend

As table_id for VRF with netns backend is main table ( RT_TABLE_MAIN or
zebrad.rtm_table_default), this makes possible to return the table id
that wants to be configured for those cases. ( in addition to default
VRF). In other cases ( VRF Lite presumably), then vrf table_id is
returned.

Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>

zebra/zebra_static.c

@@ -49,7 +49,9 @@ void static_install_route(afi_t afi, safi_t safi, struct prefix *p,
 	struct vrf *nh_vrf;
 
 	/* Lookup table.  */
-	table = zebra_vrf_table(afi, safi, si->vrf_id);
+	table = zebra_vrf_table_with_table_id(afi, safi,
+					      si->vrf_id,
+					      si->table_id);
 	if (!table)
 		return;
 
@@ -170,10 +172,20 @@ void static_install_route(afi_t afi, safi_t safi, struct prefix *p,
 		re->metric = 0;
 		re->mtu = 0;
 		re->vrf_id = si->vrf_id;
-		re->table =
+		if (!vrf_is_backend_netns()) {
-			(si->vrf_id != VRF_DEFAULT)
+			re->table =
+				(si->vrf_id != VRF_DEFAULT)
 				? (zebra_vrf_lookup_by_id(si->vrf_id))->table_id
 				: zebrad.rtm_table_default;
+		} else {
+			struct zebra_vrf *zvrf = zebra_vrf_lookup_by_id(si->vrf_id);
+
+			if (zvrf->table_id != RT_TABLE_MAIN ||
+			    zvrf->table_id != zebrad.rtm_table_default)
+				re->table = zvrf->table_id;
+			else
+				re->table = zebrad.rtm_table_default;
+		}
 		re->nexthop_num = 0;
 		re->tag = si->tag;
 
@@ -290,7 +302,9 @@ void static_uninstall_route(afi_t afi, safi_t safi, struct prefix *p,
 	struct prefix nh_p;
 
 	/* Lookup table.  */
-	table = zebra_vrf_table(afi, safi, si->vrf_id);
+	table = zebra_vrf_table_with_table_id(afi, safi,
+					      si->vrf_id,
+					      si->table_id);
 	if (!table)
 		return;
 

zebra/zebra_vrf.c

@@ -328,7 +328,9 @@ int zebra_vrf_has_config(struct zebra_vrf *zvrf)
 }
 
 /* Lookup the routing table in a VRF based on both VRF-Id and table-id.
- * NOTE: Table-id is relevant only in the Default VRF.
+ * NOTE: Table-id is relevant on two modes:
+ * - case VRF backend is default : on default VRF only
+ * - case VRF backend is netns : on all VRFs
  */
 struct route_table *zebra_vrf_table_with_table_id(afi_t afi, safi_t safi,
 						  vrf_id_t vrf_id,
@@ -346,6 +348,13 @@ struct route_table *zebra_vrf_table_with_table_id(afi_t afi, safi_t safi,
 		else
 			table = zebra_vrf_other_route_table(afi, table_id,
 							    vrf_id);
+	} else if (vrf_is_backend_netns()) {
+		if (table_id == RT_TABLE_MAIN
+		    || table_id == zebrad.rtm_table_default)
+			table = zebra_vrf_table(afi, safi, vrf_id);
+		else
+			table = zebra_vrf_other_route_table(afi, table_id,
+							    vrf_id);
 	} else
 		table = zebra_vrf_table(afi, safi, vrf_id);
 
@@ -434,7 +443,8 @@ struct zebra_vrf *zebra_vrf_alloc(void)
 	zebra_vxlan_init_tables(zvrf);
 	zebra_mpls_init_tables(zvrf);
 	zebra_pw_init(zvrf);
-
+	zvrf->table_id = RT_TABLE_MAIN;
+	/* by default table ID is default one */
 	return zvrf;
 }
 
@@ -501,9 +511,16 @@ struct route_table *zebra_vrf_other_route_table(afi_t afi, uint32_t table_id,
 	if (afi >= AFI_MAX)
 		return NULL;
 
-	if ((vrf_id == VRF_DEFAULT) && (table_id != RT_TABLE_MAIN)
+	if ((table_id != RT_TABLE_MAIN)
 	    && (table_id != zebrad.rtm_table_default)) {
-		return zebra_ns_get_table(zns, zvrf, table_id, afi);
+		if (zvrf->table_id == RT_TABLE_MAIN ||
+		    zvrf->table_id == zebrad.rtm_table_default) {
+			/* this VRF use default table
+			 * so in all cases, it does not use specific table
+			 * so it is possible to configure tables in this VRF
+			 */
+			return zebra_ns_get_table(zns, zvrf, table_id, afi);
+		}
 	}
 
 	return zvrf->table[afi][SAFI_UNICAST];

zebra/zebra_vty.c

@@ -355,6 +355,23 @@ static int zebra_static_route_leak(
 			mask_str, src_str, gate_str, ifname, flag_str, tag_str,
 			distance_str, label_str, table_str);
 	}
+	if (table_str) {
+		/* table configured. check consistent with vrf config
+		 */
+		if (zvrf->table_id != RT_TABLE_MAIN &&
+		    zvrf->table_id != zebrad.rtm_table_default) {
+			if (vty)
+				vty_out(vty,
+				    "%% Table %s overlaps vrf table %u\n",
+				    table_str, zvrf->table_id);
+			else
+				zlog_warn(
+				    "%s: Table %s overlaps vrf table %u",
+				    __PRETTY_FUNCTION__,
+				    table_str, zvrf->table_id);
+			return CMD_WARNING_CONFIG_FAILED;
+		}
+	}
 
 	/* Administrative distance. */
 	if (distance_str)
@@ -2644,6 +2661,11 @@ int static_config(struct vty *vty, struct zebra_vrf *zvrf, afi_t afi,
 				vty_out(vty, " nexthop-vrf %s", si->nh_vrfname);
 			}
 
+			/* table ID from VRF overrides configured
+			 */
+			if (si->table_id && zvrf->table_id == RT_TABLE_MAIN)
+				vty_out(vty, " table %u", si->table_id);
+
 			vty_out(vty, "\n");
 
 			write = 1;