bgpd: support for filtering EVPN routes based on route-types.

In many situations, it is desirable to only exchange EVPN routes of a particular type.
For e.g., a common deployment scenario for large DCs
is to sub-divide the DC into multiple PODs with full host mobility within a POD
(i.e., all subnets provisioned on all leaf switches within the POD)
but only do prefix-based routing across PODs.
This can be achieved by only exchanging EVPN type-5 routes across PODs.

Implement a policy to filter EVPN routes based on route type.

Ticket: CM-19394
Review: CCR-7139
Testing: Manual

Signed-off-by: Mitesh Kanjariya <mitesh@cumulusnetworks.com>

bgpd/bgp_routemap.c

@@ -696,6 +696,58 @@ struct route_map_rule_cmd route_match_evpn_vni_cmd = {
 	"evpn vni", route_match_vni, route_match_vni_compile,
 	route_match_vni_free};
 
+/* `match evpn route-type' */
+
+/* Match function should return 1 if match is success else return
+   zero. */
+static route_map_result_t route_match_evpn_route_type(void *rule,
+						      struct prefix *prefix,
+						      route_map_object_t type,
+						      void *object)
+{
+	u_char route_type = 0;
+
+	if (type == RMAP_BGP) {
+		route_type = *((u_char *)rule);
+
+		if (route_type == prefix->u.prefix_evpn.route_type)
+			return RMAP_MATCH;
+	}
+
+	return RMAP_NOMATCH;
+}
+
+/* Route map `route-type' match statement. */
+static void *route_match_evpn_route_type_compile(const char *arg)
+{
+	u_char *route_type = NULL;
+
+	route_type = XMALLOC(MTYPE_ROUTE_MAP_COMPILED, sizeof(u_char));
+	if (!route_type)
+		return NULL;
+
+	if (strncmp(arg, "ma", 2) == 0)
+		*route_type = BGP_EVPN_MAC_IP_ROUTE;
+	else if (strncmp(arg, "mu", 2) == 0)
+		*route_type = BGP_EVPN_IMET_ROUTE;
+	else
+		*route_type = BGP_EVPN_IP_PREFIX_ROUTE;
+
+	return route_type;
+}
+
+/* Free route map's compiled `route-type' value. */
+static void route_match_evpn_route_type_free(void *rule)
+{
+	XFREE(MTYPE_ROUTE_MAP_COMPILED, rule);
+}
+
+/* Route map commands for evpn route-type  matching. */
+struct route_map_rule_cmd route_match_evpn_route_type_cmd = {
+	"evpn route-type", route_match_evpn_route_type,
+	route_match_evpn_route_type_compile,
+	route_match_evpn_route_type_free};
+
 /* `match local-preference LOCAL-PREF' */
 
 /* Match function return 1 if match is success else return zero. */
@@ -3132,6 +3184,36 @@ DEFUN (no_match_mac_address,
 				      RMAP_EVENT_FILTER_DELETED);
 }
 
+DEFUN (match_evpn_route_type,
+       match_evpn_route_type_cmd,
+       "match evpn route-type {macip | multicast | prefix}",
+       MATCH_STR
+       EVPN_HELP_STR
+       "Match route-type\n"
+       "mac-ip route\n"
+       "IMET route\n"
+       "prefix route\n")
+{
+	return bgp_route_match_add(vty, "evpn route-type", argv[3]->arg,
+				   RMAP_EVENT_MATCH_ADDED);
+}
+
+DEFUN (no_match_evpn_route_type,
+       no_match_evpn_route_type_cmd,
+       "no match evpn route-type {macip | multicast | prefix}",
+       NO_STR
+       MATCH_STR
+       EVPN_HELP_STR
+       "Match route-type\n"
+       "mac-ip route\n"
+       "IMET route\n"
+       "prefix route\n")
+{
+	return bgp_route_match_delete(vty, "evpn route-type", argv[4]->arg,
+				      RMAP_EVENT_MATCH_DELETED);
+}
+
+
 DEFUN (match_evpn_vni,
        match_evpn_vni_cmd,
        "match evpn vni (1-16777215)",
@@ -4534,6 +4616,7 @@ void bgp_route_map_init(void)
 	route_map_install_match(&route_match_tag_cmd);
 	route_map_install_match(&route_match_mac_address_cmd);
 	route_map_install_match(&route_match_evpn_vni_cmd);
+	route_map_install_match(&route_match_evpn_route_type_cmd);
 
 	route_map_install_set(&route_set_ip_nexthop_cmd);
 	route_map_install_set(&route_set_local_pref_cmd);
@@ -4568,6 +4651,8 @@ void bgp_route_map_init(void)
 	install_element(RMAP_NODE, &no_match_mac_address_cmd);
 	install_element(RMAP_NODE, &match_evpn_vni_cmd);
 	install_element(RMAP_NODE, &no_match_evpn_vni_cmd);
+	install_element(RMAP_NODE, &match_evpn_route_type_cmd);
+	install_element(RMAP_NODE, &no_match_evpn_route_type_cmd);
 
 	install_element(RMAP_NODE, &match_aspath_cmd);
 	install_element(RMAP_NODE, &no_match_aspath_cmd);