diff --git a/ospf6d/ospf6_network.h b/ospf6d/ospf6_network.h
index f4b74fa..4fa2839 100644
--- a/ospf6d/ospf6_network.h
+++ b/ospf6d/ospf6_network.h
@@ -29,7 +29,7 @@
 extern struct in6_addr alldrouters6;
 
 extern int ospf6_serv_sock (void);
-extern void ospf6_sso (ifindex_t ifindex, struct in6_addr *group, int option);
+extern int ospf6_sso (ifindex_t ifindex, struct in6_addr *group, int option);
 
 extern int ospf6_sendmsg (struct in6_addr *, struct in6_addr *,
                           ifindex_t *, struct iovec *);