diff --git a/libc/kernel/uapi/linux/xfrm.h b/libc/kernel/uapi/linux/xfrm.h
index ea0ef5e..b0e930c 100644
--- a/libc/kernel/uapi/linux/xfrm.h
+++ b/libc/kernel/uapi/linux/xfrm.h
@@ -328,6 +328,7 @@
 #define XFRM_STATE_ESN 128
 };
 #define XFRM_SA_XFLAG_DONT_ENCAP_DSCP 1
+#define XFRM_SA_XFLAG_OSEQ_MAY_WRAP 2
 struct xfrm_usersa_id {
   xfrm_address_t daddr;
   __be32 spi;