diff --git a/src/vnet/ip6-nd/ip6_ra.h b/src/vnet/ip6-nd/ip6_ra.h
index d09e8c0..c501247 100644
--- a/src/vnet/ip6-nd/ip6_ra.h
+++ b/src/vnet/ip6-nd/ip6_ra.h
@@ -82,7 +82,7 @@
 					       u32 primary_sw_if_index,
 					       u32 valid_time,
 					       u32 preferred_time);
-
+extern u8 ip6_ra_adv_enabled (u32 sw_if_index);
 #endif /* included_ip6_neighbor_h */
 
 /*