Finish r275196: do not dereference rtentry in if_output() routines.

The only piece of information that is required is rt_flags subset.

In particular, if_loop() requires RTF_REJECT and RTF_BLACKHOLE flags
  to check if this particular mbuf needs to be dropped (and what
  error should be returned).
Note that if_loop() will always return EHOSTUNREACH for "reject" routes
  regardless of RTF_HOST flag existence. This is due to upcoming routing
  changes where RTF_HOST value won't be available as lookup result.

All other functions require RTF_GATEWAY flag to check if they need
  to return EHOSTUNREACH instead of EHOSTDOWN error.

There are 11 places where non-zero 'struct route' is passed to if_output().
For most of the callers (forwarding, bpf, arp) does not care about exact
  error value. In fact, the only place where this result is propagated
  is ip_output(). (ip6_output() passes NULL route to nd6_output_ifp()).

Given that, add 3 new 'struct route' flags (RT_REJECT, RT_BLACKHOLE and
  RT_IS_GW) and inline function (rt_update_ro_flags()) to copy necessary
  rte flags to ro_flags. Call this function in ip_output() after looking up/
  verifying rte.

Reviewed by:	ae

1 files changed, 2 insertions, 7 deletions

diff --git a/sys/net/if_fwsubr.c b/sys/net/if_fwsubr.c
index 626b1cb..a070f61 100644
--- a/sys/net/if_fwsubr.c
+++ b/sys/net/if_fwsubr.c
@@ -106,9 +106,8 @@ firewire_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
 	}
 
 #if defined(INET) || defined(INET6)
-	if (ro != NULL && ro->ro_rt != NULL &&
-	    (ro->ro_rt->rt_flags & RTF_GATEWAY) != 0)
-		is_gw = 1;
+	if (ro != NULL)
+		is_gw = (ro->ro_flags & RT_HAS_GW) != 0;
 #endif
 	/*
 	 * For unicast, we make a tag to store the lladdr of the
@@ -145,10 +144,6 @@ firewire_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
 		 * doesn't fit into the arp model.
 		 */
 		if (unicast) {
-			is_gw = 0;
-			if (ro != NULL && ro->ro_rt != NULL &&
-			    (ro->ro_rt->rt_flags & RTF_GATEWAY) != 0)
-				is_gw = 1;
 			error = arpresolve(ifp, is_gw, m, dst, (u_char *) destfw, NULL);
 			if (error)
 				return (error == EWOULDBLOCK ? 0 : error);