diff --git a/include/netinet/in.h b/include/netinet/in.h
index 622bdfec..04cc81cd 100644
--- a/include/netinet/in.h
+++ b/include/netinet/in.h
@@ -344,6 +344,7 @@ struct ip6_mtuinfo
 #define IPV6_LEAVE_ANYCAST      28
 #define IPV6_IPSEC_POLICY       34
 #define IPV6_XFRM_POLICY        35
+#define IPV6_HDRINCL            36
 
 #define IPV6_RECVPKTINFO        49
 #define IPV6_PKTINFO            50