1 files changed, 32 insertions, 2 deletions

diff --git a/isisd/isis_circuit.c b/isisd/isis_circuit.c
index 28d4b530fc..26e1de20f7 100644
--- a/isisd/isis_circuit.c
+++ b/isisd/isis_circuit.c
@@ -593,6 +593,27 @@ size_t isis_circuit_pdu_size(struct isis_circuit *circuit)
 	return ISO_MTU(circuit);
 }
 
+static bool isis_circuit_lfa_enabled(struct isis_circuit *circuit, int level)
+{
+	return (circuit->lfa_protection[level - 1] ||
+		circuit->rlfa_protection[level - 1] ||
+		circuit->tilfa_protection[level - 1]);
+}
+
+void isis_circuit_switchover_routes(struct isis_circuit *circuit, int family,
+				    union g_addr *nexthop_ip, ifindex_t ifindex)
+{
+	char is_type = circuit->area->is_type;
+	if ((is_type == IS_LEVEL_1 || is_type == IS_LEVEL_1_AND_2) &&
+	    isis_circuit_lfa_enabled(circuit, IS_LEVEL_1))
+		isis_area_switchover_routes(circuit->area, family, nexthop_ip,
+					    ifindex, IS_LEVEL_1);
+	if ((is_type == IS_LEVEL_2 || is_type == IS_LEVEL_1_AND_2) &&
+	    isis_circuit_lfa_enabled(circuit, IS_LEVEL_2))
+		isis_area_switchover_routes(circuit->area, family, nexthop_ip,
+					    ifindex, IS_LEVEL_2);
+}
+
 void isis_circuit_stream(struct isis_circuit *circuit, struct stream **stream)
 {
 	size_t stream_size = isis_circuit_pdu_size(circuit);
@@ -1597,17 +1618,26 @@ static int isis_ifp_up(struct interface *ifp)
 {
 	struct isis_circuit *circuit = ifp->info;
 
-	if (circuit)
+	if (circuit) {
+		UNSET_FLAG(circuit->flags, ISIS_CIRCUIT_IF_DOWN_FROM_Z);
 		isis_csm_state_change(IF_UP_FROM_Z, circuit, ifp);
+	}
 
 	return 0;
 }
 
 static int isis_ifp_down(struct interface *ifp)
 {
+	afi_t afi;
 	struct isis_circuit *circuit = ifp->info;
 
-	if (circuit) {
+	if (circuit &&
+	    !CHECK_FLAG(circuit->flags, ISIS_CIRCUIT_IF_DOWN_FROM_Z)) {
+		SET_FLAG(circuit->flags, ISIS_CIRCUIT_IF_DOWN_FROM_Z);
+		for (afi = AFI_IP; afi <= AFI_IP6; afi++)
+			isis_circuit_switchover_routes(
+				circuit, afi == AFI_IP ? AF_INET : AF_INET6,
+				NULL, ifp->ifindex);
 		isis_csm_state_change(IF_DOWN_FROM_Z, circuit, ifp);
 
 		SET_FLAG(circuit->flags, ISIS_CIRCUIT_FLAPPED_AFTER_SPF);