+ /*
+ * the special INVALID label meams we are not recursing via a
+ * label. Exp-null value is never a valid via-label so that
+ * also means it's not a via-label and means clients that set
+ * it to 0 by default get the expected behaviour
+ */
+ if ((MPLS_LABEL_INVALID != next_hop_via_label) && (0 != next_hop_via_label))