diff --git a/libc/kernel/uapi/linux/stm.h b/libc/kernel/uapi/linux/stm.h
index 497d674..1c7f7f3 100644
--- a/libc/kernel/uapi/linux/stm.h
+++ b/libc/kernel/uapi/linux/stm.h
@@ -19,6 +19,8 @@
 #ifndef _UAPI_LINUX_STM_H
 #define _UAPI_LINUX_STM_H
 #include <linux/types.h>
+#define STP_MASTER_MAX 0xffff
+#define STP_CHANNEL_MAX 0xffff
 struct stp_policy_id {
   __u32 size;
   __u16 master;