diff --git a/ospfd/ospf_packet.c b/ospfd/ospf_packet.c
index 8bc4966..4d15825 100644
--- a/ospfd/ospf_packet.c
+++ b/ospfd/ospf_packet.c
@@ -1883,7 +1883,7 @@
   struct cmsghdr *cmsg;
 #if defined(CMSG_SPACE)
   /* Header and data both require alignment. */
-  char buff [CMSG_SPACE(SIZE_CMSG_IFINDEX_IPV4())];
+  char buff [CMSG_SPACE(SOPT_SIZE_CMSG_IFINDEX_IPV4())];
 #else
   char buff [sizeof (*cmsg) + SOPT_SIZE_CMSG_IFINDEX_IPV4()];
 #endif