Hide struct rtentry from userland.

sys/net/route.h

@@ -105,6 +105,8 @@ struct mbuf;
 #include <net/radix_mpath.h>
 #endif
 #endif
+
+#if defined(_KERNEL) || defined(_WANT_RTENTRY)
 struct rtentry {
 	struct	radix_node rt_nodes[2];	/* tree glue, and other values */
 	/*
@@ -127,6 +129,7 @@ struct rtentry {
 	counter_u64_t	rt_pksent;	/* packets sent using this route */
 	struct mtx	rt_mtx;		/* mutex for routing entry */
 };
+#endif /* _KERNEL || _WANT_RTENTRY */
 
 /*
  * Following structure necessary for 4.3 compatibility;

usr.bin/netstat/route.c

@@ -48,6 +48,7 @@ __FBSDID("$FreeBSD$");
 #include <net/if_dl.h>
 #include <net/if_types.h>
 #include <net/radix.h>
+#define	_WANT_RTENTRY
 #include <net/route.h>
 
 #include <netinet/in.h>