diff --git a/libc/kernel/uapi/linux/in6.h b/libc/kernel/uapi/linux/in6.h
index bd07302..d6c3394 100644
--- a/libc/kernel/uapi/linux/in6.h
+++ b/libc/kernel/uapi/linux/in6.h
@@ -213,4 +213,6 @@
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define IPV6_TRANSPARENT 75
 #define IPV6_UNICAST_IF 76
+#define IPV6_RECVFRAGSIZE 77
 #endif
+/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */