Merge pull request #5334 from adharkar/frr-master-nexthop_check

bgpd: Add nexthop of received EVPN RT-5 for nexthop tracking

bgpd/bgp_attr.h

@@ -69,6 +69,10 @@
 #define BGP_PREFIX_SID_IPV6_LENGTH            19
 #define BGP_PREFIX_SID_ORIGINATOR_SRGB_LENGTH  6
 
+#define BGP_ATTR_NH_AFI(afi, attr) \
+	((afi != AFI_L2VPN) ? afi : \
+	((attr->mp_nexthop_len == BGP_ATTR_NHLEN_IPV4) ? AFI_IP : AFI_IP6))
+
 /* PMSI tunnel types (RFC 6514) */
 
 struct bgp_attr_encap_subtlv {

bgpd/bgp_evpn.c

@@ -6030,3 +6030,26 @@ int bgp_evpn_get_type5_prefixlen(struct prefix *pfx)
 
 	return evp->prefix.prefix_addr.ip_prefix_length;
 }
+
+/*
+ * Should we register nexthop for this EVPN prefix for nexthop tracking?
+ */
+bool bgp_evpn_is_prefix_nht_supported(struct prefix *pfx)
+{
+	struct prefix_evpn *evp = (struct prefix_evpn *)pfx;
+
+	/*
+	 * EVPN RT-5 should not be marked as valid and imported to vrfs if the
+	 * BGP nexthop is not reachable. To check for the nexthop reachability,
+	 * Add nexthop for EVPN RT-5 for nexthop tracking.
+	 *
+	 * Ideally, a BGP route should be marked as valid only if the
+	 * nexthop is reachable. Thus, other EVPN route types also should be
+	 * added here after testing is performed for them.
+	 */
+	if (pfx && pfx->family == AF_EVPN &&
+	    evp->prefix.route_type == BGP_EVPN_IP_PREFIX_ROUTE)
+		return true;
+
+	return false;
+}

bgpd/bgp_evpn.h

@@ -191,5 +191,6 @@ extern void bgp_evpn_cleanup_on_disable(struct bgp *bgp);
 extern void bgp_evpn_cleanup(struct bgp *bgp);
 extern void bgp_evpn_init(struct bgp *bgp);
 extern int bgp_evpn_get_type5_prefixlen(struct prefix *pfx);
+extern bool bgp_evpn_is_prefix_nht_supported(struct prefix *pfx);
 
 #endif /* _QUAGGA_BGP_EVPN_H */

bgpd/bgp_nht.c

@@ -43,6 +43,7 @@
 #include "bgpd/bgp_fsm.h"
 #include "bgpd/bgp_zebra.h"
 #include "bgpd/bgp_flowspec_util.h"
+#include "bgpd/bgp_evpn.h"
 
 extern struct zclient *zclient;
 
@@ -773,6 +774,16 @@ static void evaluate_paths(struct bgp_nexthop_cache *bnc)
 		    || CHECK_FLAG(bnc->change_flags, BGP_NEXTHOP_CHANGED))
 			SET_FLAG(path->flags, BGP_PATH_IGP_CHANGED);
 
+		if (safi == SAFI_EVPN &&
+		    bgp_evpn_is_prefix_nht_supported(&rn->p)) {
+			if (CHECK_FLAG(path->flags, BGP_PATH_VALID))
+				bgp_evpn_import_route(bgp_path, afi, safi,
+						      &rn->p, path);
+			else
+				bgp_evpn_unimport_route(bgp_path, afi, safi,
+							&rn->p, path);
+		}
+
 		bgp_process(bgp_path, rn, afi, safi);
 	}
 

bgpd/bgp_route.c

@@ -3041,6 +3041,7 @@ int bgp_update(struct peer *peer, struct prefix *p, uint32_t addpath_id,
 	int connected = 0;
 	int do_loop_check = 1;
 	int has_valid_label = 0;
+	afi_t nh_afi;
 #if ENABLE_BGP_VNC
 	int vnc_implicit_withdraw = 0;
 #endif
@@ -3436,8 +3437,10 @@ int bgp_update(struct peer *peer, struct prefix *p, uint32_t addpath_id,
 
 		/* Nexthop reachability check - for unicast and
 		 * labeled-unicast.. */
-		if ((afi == AFI_IP || afi == AFI_IP6)
+		if (((afi == AFI_IP || afi == AFI_IP6)
-		    && (safi == SAFI_UNICAST || safi == SAFI_LABELED_UNICAST)) {
+		    && (safi == SAFI_UNICAST || safi == SAFI_LABELED_UNICAST))
+		    || (safi == SAFI_EVPN &&
+			bgp_evpn_is_prefix_nht_supported(p))) {
 			if (peer->sort == BGP_PEER_EBGP && peer->ttl == 1
 			    && !CHECK_FLAG(peer->flags,
 					   PEER_FLAG_DISABLE_CONNECTED_CHECK)
@@ -3452,8 +3455,10 @@ int bgp_update(struct peer *peer, struct prefix *p, uint32_t addpath_id,
 			if (pi->extra && pi->extra->bgp_orig)
 				bgp_nexthop = pi->extra->bgp_orig;
 
-			if (bgp_find_or_add_nexthop(bgp, bgp_nexthop, afi, pi,
+			nh_afi = BGP_ATTR_NH_AFI(afi, pi->attr);
-						    NULL, connected)
+
+			if (bgp_find_or_add_nexthop(bgp, bgp_nexthop, nh_afi,
+						    pi, NULL, connected)
 			    || CHECK_FLAG(peer->flags, PEER_FLAG_IS_RFAPI_HD))
 				bgp_path_info_set_flag(rn, pi, BGP_PATH_VALID);
 			else {
@@ -3501,7 +3506,8 @@ int bgp_update(struct peer *peer, struct prefix *p, uint32_t addpath_id,
 		 * updating
 		 * the attributes for the route in the VNI(s).
 		 */
-		if (safi == SAFI_EVPN && !same_attr)
+		if (safi == SAFI_EVPN && !same_attr &&
+		    CHECK_FLAG(pi->flags, BGP_PATH_VALID))
 			bgp_evpn_import_route(bgp, afi, safi, p, pi);
 
 		/* Process change. */
@@ -3574,8 +3580,9 @@ int bgp_update(struct peer *peer, struct prefix *p, uint32_t addpath_id,
 				     evpn == NULL ? NULL : &evpn->gw_ip);
 	}
 	/* Nexthop reachability check. */
-	if ((afi == AFI_IP || afi == AFI_IP6)
+	if (((afi == AFI_IP || afi == AFI_IP6)
-	    && (safi == SAFI_UNICAST || safi == SAFI_LABELED_UNICAST)) {
+	    && (safi == SAFI_UNICAST || safi == SAFI_LABELED_UNICAST))
+	    || (safi == SAFI_EVPN && bgp_evpn_is_prefix_nht_supported(p))) {
 		if (peer->sort == BGP_PEER_EBGP && peer->ttl == 1
 		    && !CHECK_FLAG(peer->flags,
 				   PEER_FLAG_DISABLE_CONNECTED_CHECK)
@@ -3584,7 +3591,10 @@ int bgp_update(struct peer *peer, struct prefix *p, uint32_t addpath_id,
 		else
 			connected = 0;
 
-		if (bgp_find_or_add_nexthop(bgp, bgp, afi, new, NULL, connected)
+		nh_afi = BGP_ATTR_NH_AFI(afi, new->attr);
+
+		if (bgp_find_or_add_nexthop(bgp, bgp, nh_afi, new, NULL,
+					    connected)
 		    || CHECK_FLAG(peer->flags, PEER_FLAG_IS_RFAPI_HD))
 			bgp_path_info_set_flag(rn, new, BGP_PATH_VALID);
 		else {
@@ -3635,7 +3645,7 @@ int bgp_update(struct peer *peer, struct prefix *p, uint32_t addpath_id,
 		return -1;
 
 	/* If this is an EVPN route, process for import. */
-	if (safi == SAFI_EVPN)
+	if (safi == SAFI_EVPN && CHECK_FLAG(new->flags, BGP_PATH_VALID))
 		bgp_evpn_import_route(bgp, afi, safi, p, new);
 
 	hook_call(bgp_process, bgp, afi, safi, rn, peer, false);