diff --git a/libc/kernel/uapi/linux/icmpv6.h b/libc/kernel/uapi/linux/icmpv6.h
index fd03585..ef73a7c 100644
--- a/libc/kernel/uapi/linux/icmpv6.h
+++ b/libc/kernel/uapi/linux/icmpv6.h
@@ -90,6 +90,7 @@
 #define ICMPV6_DHAAD_REPLY 145
 #define ICMPV6_MOBILE_PREFIX_SOL 146
 #define ICMPV6_MOBILE_PREFIX_ADV 147
+#define ICMPV6_MRDISC_ADV 151
 #define ICMPV6_NOROUTE 0
 #define ICMPV6_ADM_PROHIBITED 1
 #define ICMPV6_NOT_NEIGHBOUR 2