Merge pull request #6421 from vivek-cumulus/zebra_trust_onlink

zebra: Trust onlink flag for nexthop active resolution

2 files changed, 18 insertions, 23 deletions

diff --git a/zebra/zapi_msg.c b/zebra/zapi_msg.c
index 092b5dd3c2..5db4555284 100644
--- a/zebra/zapi_msg.c
+++ b/zebra/zapi_msg.c
@@ -1451,10 +1451,6 @@ static struct nexthop *nexthop_from_zapi(struct route_entry *re,
 			&api_nh->gate.ipv4, NULL, api_nh->ifindex,
 			api_nh->vrf_id);
 
-		ifp = if_lookup_by_index(api_nh->ifindex, api_nh->vrf_id);
-		if (ifp && connected_is_unnumbered(ifp))
-			SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ONLINK);
-
 		/* Special handling for IPv4 routes sourced from EVPN:
 		 * the nexthop and associated MAC need to be installed.
 		 */
@@ -1516,8 +1512,16 @@ static struct nexthop *nexthop_from_zapi(struct route_entry *re,
 		goto done;
 	}
 
+	/* Mark nexthop as onlink either if client has explicitly told us
+	 * to or if the nexthop is on an 'unnumbered' interface.
+	 */
 	if (CHECK_FLAG(api_nh->flags, ZAPI_NEXTHOP_FLAG_ONLINK))
 		SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ONLINK);
+	else if (api_nh->type == NEXTHOP_TYPE_IPV4_IFINDEX) {
+		ifp = if_lookup_by_index(api_nh->ifindex, api_nh->vrf_id);
+		if (ifp && connected_is_unnumbered(ifp))
+			SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ONLINK);
+	}
 
 	if (CHECK_FLAG(api_nh->flags, ZAPI_NEXTHOP_FLAG_WEIGHT))
 		nexthop->weight = api_nh->weight;
diff --git a/zebra/zebra_nhg.c b/zebra/zebra_nhg.c
index f24552c80b..fdbeac88e1 100644
--- a/zebra/zebra_nhg.c
+++ b/zebra/zebra_nhg.c
@@ -1776,33 +1776,24 @@ static int nexthop_active(afi_t afi, struct route_entry *re,
 		return 1;
 
 	/*
-	 * Check to see if we should trust the passed in information
-	 * for UNNUMBERED interfaces as that we won't find the GW
-	 * address in the routing table.
-	 * This check should suffice to handle IPv4 or IPv6 routes
-	 * sourced from EVPN routes which are installed with the
-	 * next hop as the remote VTEP IP.
+	 * If the nexthop has been marked as 'onlink' we just need to make
+	 * sure the nexthop's interface is known and is operational.
 	 */
 	if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_ONLINK)) {
 		ifp = if_lookup_by_index(nexthop->ifindex, nexthop->vrf_id);
 		if (!ifp) {
-			if (IS_ZEBRA_DEBUG_RIB_DETAILED)
-				zlog_debug(
-					"        %s: Onlink and interface: %u[%u] does not exist",
-					__func__, nexthop->ifindex,
-					nexthop->vrf_id);
+			if (IS_ZEBRA_DEBUG_NHG_DETAIL)
+				zlog_debug("nexthop %pNHv marked onlink but nhif %u doesn't exist",
+					   nexthop, nexthop->ifindex);
 			return 0;
 		}
-
-		if (if_is_operative(ifp))
-			return 1;
-		else {
-			if (IS_ZEBRA_DEBUG_RIB_DETAILED)
-				zlog_debug(
-					"        %s: Onlink and interface %s is not operative",
-					__func__, ifp->name);
+		if (!if_is_operative(ifp)) {
+			if (IS_ZEBRA_DEBUG_NHG_DETAIL)
+				zlog_debug("nexthop %pNHv marked onlink but nhif %s is not operational",
+					   nexthop, ifp->name);
 			return 0;
 		}
+		return 1;
 	}
 
 	if ((top->p.family == AF_INET && top->p.prefixlen == 32