bgpd: Ensure EVPN routes are not injected back into EVPN

EVPN type-2 and type-5 routes received with a L3 VNI and corresponding RTs
are installed into the appropriate BGP RIB. Ensure that these routes are not
re-injected back into EVPN as type-5 routes when type-5 advertisement is
enabled; only regular IPv4 routes (and IPv6 routes in future) in the RIB
should be injected into EVPN.

As a benefit of this change, no longer restrict that EVPN type-5 routes
should be non-host routes - i.e., allow /32 IPv4 routes (and /128 IPv6
routes in future).

Signed-off-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
Signed-off-by: Mitesh Kanjariya <mitesh@cumulusnetworks.com>

Ticket: CM-19456
Reviewed By: CCR-7117
Testing Done:
1. Manual replication of problem and verification of fix
2. evpn-min

2 files changed, 20 insertions, 11 deletions

diff --git a/bgpd/bgp_evpn.c b/bgpd/bgp_evpn.c
index c7d5f8d111..a69c3465e3 100644
--- a/bgpd/bgp_evpn.c
+++ b/bgpd/bgp_evpn.c
@@ -3210,15 +3210,25 @@ void bgp_evpn_withdraw_type5_routes(struct bgp *bgp_vrf,
 {
 	struct bgp_table *table = NULL;
 	struct bgp_node *rn = NULL;
+	struct bgp_info *ri;
 
 	/* Bail out early if we don't have to advertise type-5 routes. */
 	if (!advertise_type5_routes(bgp_vrf, afi))
 		return;
 
 	table = bgp_vrf->rib[afi][safi];
-	for (rn = bgp_table_top(table); rn; rn = bgp_route_next(rn))
-		bgp_evpn_withdraw_type5_route(bgp_vrf, &rn->p, afi, safi);
-
+	for (rn = bgp_table_top(table); rn; rn = bgp_route_next(rn)) {
+		/* Only care about "selected" routes - non-imported. */
+		/* TODO: Support for AddPath for EVPN. */
+		for (ri = rn->info; ri; ri = ri->next) {
+			if (CHECK_FLAG(ri->flags, BGP_INFO_SELECTED) &&
+			    (!ri->extra || !ri->extra->parent)) {
+				bgp_evpn_withdraw_type5_route(bgp_vrf, &rn->p,
+							      afi, safi);
+				break;
+			}
+		}
+	}
 }
 
 /*
@@ -3239,10 +3249,6 @@ void bgp_evpn_advertise_type5_route(struct bgp *bgp_vrf, struct prefix *p,
 	if (!advertise_type5_routes(bgp_vrf, afi))
 		return;
 
-	/* only advertise subnet routes as type-5 */
-	if (is_host_route(p))
-		return;
-
 	build_type5_prefix_from_ip_prefix(&evp, p);
 	ret = update_evpn_type5_route(bgp_vrf, &evp, src_attr);
 	if (ret)
@@ -3270,11 +3276,12 @@ void bgp_evpn_advertise_type5_routes(struct bgp *bgp_vrf,
 	table = bgp_vrf->rib[afi][safi];
 	for (rn = bgp_table_top(table); rn; rn = bgp_route_next(rn)) {
 		/* Need to identify the "selected" route entry to use its
-		 * attribute.
+		 * attribute. Also, we only consider "non-imported" routes.
 		 * TODO: Support for AddPath for EVPN.
 		 */
 		for (ri = rn->info; ri; ri = ri->next) {
-			if (CHECK_FLAG(ri->flags, BGP_INFO_SELECTED)) {
+			if (CHECK_FLAG(ri->flags, BGP_INFO_SELECTED) &&
+			    (!ri->extra || !ri->extra->parent)) {
 				bgp_evpn_advertise_type5_route(bgp_vrf, &rn->p,
 							       ri->attr,
 							       afi, safi);
diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index 36e0c92482..fe2c5d11a1 100644
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -2225,11 +2225,13 @@ static void bgp_process_main_one(struct bgp *bgp, struct bgp_node *rn,
 
 	/* advertise/withdraw type-5 routes */
 	if ((afi == AFI_IP || afi == AFI_IP6) && (safi == SAFI_UNICAST)) {
-		if (new_select)
+		if (new_select &&
+		    (!new_select->extra || !new_select->extra->parent))
 			bgp_evpn_advertise_type5_route(bgp, &rn->p,
 						       new_select->attr,
 						       afi, safi);
-		else if (old_select)
+		else if (old_select &&
+		         (!old_select->extra || !old_select->extra->parent))
 			bgp_evpn_withdraw_type5_route(bgp, &rn->p, afi, safi);
 	}