bgpd: Memory wasting in zebra by non used MPLS FECs

Signed-off-by: Daniel Walton <dwalton@cumulusnetworks.com>

bgpd/bgp_route.c

@@ -2045,7 +2045,7 @@ static void bgp_process_main_one(struct bgp *bgp, struct bgp_node *rn,
 	 * to do this upon changes to best path except of the label index
 	 * changes.
 	 */
-	if (safi == SAFI_UNICAST) {
+	if (bgp->allocate_mpls_labels[afi][safi]) {
 		if (new_select) {
 			if (!old_select
 			    || bgp_label_index_differs(new_select, old_select)
@@ -2066,8 +2066,11 @@ static void bgp_process_main_one(struct bgp *bgp, struct bgp_node *rn,
 				} else
 					bgp_register_for_label(rn, new_select);
 			}
-		} else if (CHECK_FLAG(rn->flags, BGP_NODE_REGISTERED_FOR_LABEL))
+		} else if (CHECK_FLAG(rn->flags, BGP_NODE_REGISTERED_FOR_LABEL)) {
 			bgp_unregister_for_label(rn);
+		}
+	} else if (CHECK_FLAG(rn->flags, BGP_NODE_REGISTERED_FOR_LABEL)) {
+		bgp_unregister_for_label(rn);
 	}
 
 	/* If best route remains the same and this is not due to user-initiated

bgpd/bgp_vty.c

@@ -7018,26 +7018,6 @@ static int bgp_show_summary(struct vty *vty, struct bgp *bgp, int afi, int safi,
 	return CMD_SUCCESS;
 }
 
-/*
- * Return if we have a peer configured to use this afi/safi
- */
-static int bgp_show_summary_afi_safi_peer_exists(struct bgp *bgp, int afi,
-						 int safi)
-{
-	struct listnode *node;
-	struct peer *peer;
-
-	for (ALL_LIST_ELEMENTS_RO(bgp->peer, node, peer)) {
-		if (!CHECK_FLAG(peer->flags, PEER_FLAG_CONFIG_NODE))
-			continue;
-
-		if (peer->afc[afi][safi])
-			return 1;
-	}
-
-	return 0;
-}
-
 static void bgp_show_summary_afi_safi(struct vty *vty, struct bgp *bgp, int afi,
 				      int safi, u_char use_json,
 				      json_object *json)
@@ -7056,8 +7036,7 @@ static void bgp_show_summary_afi_safi(struct vty *vty, struct bgp *bgp, int afi,
 		if (safi_wildcard)
 			safi = 1; /* SAFI_UNICAST */
 		while (safi < SAFI_MAX) {
-			if (bgp_show_summary_afi_safi_peer_exists(bgp, afi,
+			if (bgp_afi_safi_peer_exists(bgp, afi, safi)) {
-								  safi)) {
 				json_output = true;
 				if (is_wildcard) {
 					/*

bgpd/bgpd.c

@@ -1391,6 +1391,32 @@ void bgp_peer_conf_if_to_su_update(struct peer *peer)
 	hash_get(peer->bgp->peerhash, peer, hash_alloc_intern);
 }
 
+static void bgp_recalculate_afi_safi_bestpaths(struct bgp *bgp, afi_t afi,
+					       safi_t safi)
+{
+	struct bgp_node *rn, *nrn;
+
+	for (rn = bgp_table_top(bgp->rib[afi][safi]); rn;
+	     rn = bgp_route_next(rn)) {
+		if (rn->info != NULL) {
+			/* Special handling for 2-level routing
+			 * tables. */
+			if (safi == SAFI_MPLS_VPN
+			    || safi == SAFI_ENCAP
+			    || safi == SAFI_EVPN) {
+				for (nrn = bgp_table_top((
+					     struct bgp_table
+						     *)(rn->info));
+				     nrn;
+				     nrn = bgp_route_next(nrn))
+					bgp_process(bgp, nrn,
+						    afi, safi);
+			} else
+				bgp_process(bgp, rn, afi, safi);
+		}
+	}
+}
+
 /* Force a bestpath recalculation for all prefixes.  This is used
  * when 'bgp bestpath' commands are entered.
  */
@@ -1398,29 +1424,10 @@ void bgp_recalculate_all_bestpaths(struct bgp *bgp)
 {
 	afi_t afi;
 	safi_t safi;
-	struct bgp_node *rn, *nrn;
 
 	for (afi = AFI_IP; afi < AFI_MAX; afi++) {
 		for (safi = SAFI_UNICAST; safi < SAFI_MAX; safi++) {
-			for (rn = bgp_table_top(bgp->rib[afi][safi]); rn;
+			bgp_recalculate_afi_safi_bestpaths(bgp, afi, safi);
-			     rn = bgp_route_next(rn)) {
-				if (rn->info != NULL) {
-					/* Special handling for 2-level routing
-					 * tables. */
-					if (safi == SAFI_MPLS_VPN
-					    || safi == SAFI_ENCAP
-					    || safi == SAFI_EVPN) {
-						for (nrn = bgp_table_top((
-							     struct bgp_table
-								     *)(rn->info));
-						     nrn;
-						     nrn = bgp_route_next(nrn))
-							bgp_process(bgp, nrn,
-								    afi, safi);
-					} else
-						bgp_process(bgp, rn, afi, safi);
-				}
-			}
 		}
 	}
 }
@@ -1500,6 +1507,25 @@ struct peer *peer_create_accept(struct bgp *bgp)
 	return peer;
 }
 
+/*
+ * Return true if we have a peer configured to use this afi/safi
+ */
+int bgp_afi_safi_peer_exists(struct bgp *bgp, afi_t afi, safi_t safi)
+{
+	struct listnode *node;
+	struct peer *peer;
+
+	for (ALL_LIST_ELEMENTS_RO(bgp->peer, node, peer)) {
+		if (!CHECK_FLAG(peer->flags, PEER_FLAG_CONFIG_NODE))
+			continue;
+
+		if (peer->afc[afi][safi])
+			return 1;
+	}
+
+	return 0;
+}
+
 /* Change peer's AS number.  */
 void peer_as_change(struct peer *peer, as_t as, int as_specified)
 {
@@ -1714,11 +1740,14 @@ int peer_activate(struct peer *peer, afi_t afi, safi_t safi)
 	struct peer_group *group;
 	struct listnode *node, *nnode;
 	struct peer *tmp_peer;
+	struct bgp *bgp;
 
 	/* Nothing to do if we've already activated this peer */
 	if (peer->afc[afi][safi])
 		return ret;
 
+	bgp = peer->bgp;
+
 	/* This is a peer-group so activate all of the members of the
 	 * peer-group as well */
 	if (CHECK_FLAG(peer->sflags, PEER_STATUS_GROUP)) {
@@ -1741,6 +1770,17 @@ int peer_activate(struct peer *peer, afi_t afi, safi_t safi)
 		ret |= non_peergroup_activate_af(peer, afi, safi);
 	}
 
+	/* If this is the first peer to be activated for this afi/labeled-unicast
+	 * recalc bestpaths to trigger label allocation */
+	if (safi == SAFI_LABELED_UNICAST && !bgp->allocate_mpls_labels[afi][SAFI_UNICAST]) {
+
+		if (BGP_DEBUG(zebra, ZEBRA))
+			zlog_info("peer(s) are now active for labeled-unicast, allocate MPLS labels");
+
+		bgp->allocate_mpls_labels[afi][SAFI_UNICAST] = 1;
+		bgp_recalculate_afi_safi_bestpaths(bgp, afi, SAFI_UNICAST);
+	}
+
 	return ret;
 }
 
@@ -1798,6 +1838,7 @@ int peer_deactivate(struct peer *peer, afi_t afi, safi_t safi)
 	struct peer_group *group;
 	struct peer *tmp_peer;
 	struct listnode *node, *nnode;
+	struct bgp *bgp;
 
 	/* Nothing to do if we've already de-activated this peer */
 	if (!peer->afc[afi][safi])
@@ -1821,6 +1862,20 @@ int peer_deactivate(struct peer *peer, afi_t afi, safi_t safi)
 		ret |= non_peergroup_deactivate_af(peer, afi, safi);
 	}
 
+	bgp = peer->bgp;
+
+	/* If this is the last peer to be deactivated for this afi/labeled-unicast
+	 * recalc bestpaths to trigger label deallocation */
+	if (safi == SAFI_LABELED_UNICAST &&
+	    bgp->allocate_mpls_labels[afi][SAFI_UNICAST] &&
+	    !bgp_afi_safi_peer_exists(bgp, afi, safi)) {
+
+		if (BGP_DEBUG(zebra, ZEBRA))
+			zlog_info("peer(s) are no longer active for labeled-unicast, deallocate MPLS labels");
+
+		bgp->allocate_mpls_labels[afi][SAFI_UNICAST] = 0;
+		bgp_recalculate_afi_safi_bestpaths(bgp, afi, SAFI_UNICAST);
+	}
 	return ret;
 }
 

bgpd/bgpd.h

@@ -333,6 +333,9 @@ struct bgp {
 	/* BGP redistribute configuration. */
 	struct list *redist[AFI_MAX][ZEBRA_ROUTE_MAX];
 
+	/* Allocate MPLS labels */
+	u_char allocate_mpls_labels[AFI_MAX][SAFI_MAX];
+
 	/* timer to re-evaluate neighbor default-originate route-maps */
 	struct thread *t_rmap_def_originate_eval;
 #define RMAP_DEFAULT_ORIGINATE_EVAL_TIMER 5
@@ -1280,6 +1283,7 @@ extern int bgp_listen_limit_unset(struct bgp *);
 
 extern int bgp_update_delay_active(struct bgp *);
 extern int bgp_update_delay_configured(struct bgp *);
+extern int bgp_afi_safi_peer_exists(struct bgp *bgp, afi_t afi, safi_t safi);
 extern void peer_as_change(struct peer *, as_t, int);
 extern int peer_remote_as(struct bgp *, union sockunion *, const char *, as_t *,
 			  int, afi_t, safi_t);