diff --git a/include/sys/socket.h b/include/sys/socket.h
index 67883750..2f400acb 100644
--- a/include/sys/socket.h
+++ b/include/sys/socket.h
@@ -222,6 +222,7 @@ struct linger
 #define SO_DETACH_BPF           SO_DETACH_FILTER
 #define SO_ATTACH_REUSEPORT_CBPF 51
 #define SO_ATTACH_REUSEPORT_EBPF 52
+#define SO_CNX_ADVICE           53
 
 #ifndef SOL_SOCKET
 #define SOL_SOCKET      1