--- kernel/bsd/net/route.h	2018/04/24 18:26:07	1.1.1.1
+++ kernel/bsd/net/route.h	2018/04/24 18:31:41	1.1.1.2
@@ -255,6 +255,11 @@ struct route_cb {
 		rtfree(rt); \
 	else \
 		(rt)->rt_refcnt--;
+#define RTHOLD(rt) {                    \
+        if (++(rt)->rt_refcnt <= 0)	\
+                panic("RTHOLD");	\
+}
+
 
 extern struct	route_cb route_cb;
 extern struct	rtstat	rtstat;