diff --git a/libc/kernel/uapi/linux/sysctl.h b/libc/kernel/uapi/linux/sysctl.h
index 5389d61..47c39fc 100644
--- a/libc/kernel/uapi/linux/sysctl.h
+++ b/libc/kernel/uapi/linux/sysctl.h
@@ -487,6 +487,7 @@
   NET_IPV6_PROXY_NDP = 23,
   NET_IPV6_ACCEPT_SOURCE_ROUTE = 25,
   NET_IPV6_ACCEPT_RA_FROM_LOCAL = 26,
+  NET_IPV6_ACCEPT_RA_RT_INFO_MIN_PLEN = 27,
   __NET_IPV6_MAX
 };
 enum {