When ip_output()/ip6_output() is supplied a struct route *ro argument,

it skips FLOWTABLE lookup. However, the non-NULL ro has dual meaning
here: it may be supplied to provide route, and it may be supplied to
store and return to caller the route that ip_output()/ip6_output()
finds. In the latter case skipping FLOWTABLE lookup is pessimisation.

The difference between struct route filled by FLOWTABLE and filled
by rtalloc() family is that the former doesn't hold a reference on
its rtentry. Reference is hold by flow entry, and it is about to
be released in future. Thus, route filled by FLOWTABLE shouldn't
be passed to RTFREE() macro.

- Introduce new flag for struct route/route_in6, that marks route
  not holding a reference on rtentry.
- Introduce new macro RO_RTFREE() that cleans up a struct route
  depending on its kind.
- All callers to ip_output()/ip6_output() that do supply non-NULL
  but empty route should use RO_RTFREE() to free results of
  lookup.
- ip_output()/ip6_output() now do FLOWTABLE lookup always when
  ro->ro_rt == NULL.

Tested by:	tuexen (SCTP part)

2 files changed, 16 insertions, 2 deletions

diff --git a/sys/net/flowtable.c b/sys/net/flowtable.c
index 8501b1875d85..0e50377d9941 100644
--- a/sys/net/flowtable.c
+++ b/sys/net/flowtable.c
@@ -619,6 +619,7 @@ flow_to_route(struct flentry *fle, struct route *ro)
 	sin->sin_addr.s_addr = hashkey[2];
 	ro->ro_rt = __DEVOLATILE(struct rtentry *, fle->f_rt);
 	ro->ro_lle = __DEVOLATILE(struct llentry *, fle->f_lle);
+	ro->ro_flags |= RT_NORTREF;
 }
 #endif /* INET */
 
@@ -826,7 +827,7 @@ flow_to_route_in6(struct flentry *fle, struct route_in6 *ro)
 	memcpy(&sin6->sin6_addr, &hashkey[5], sizeof (struct in6_addr));
 	ro->ro_rt = __DEVOLATILE(struct rtentry *, fle->f_rt);
 	ro->ro_lle = __DEVOLATILE(struct llentry *, fle->f_lle);
-
+	ro->ro_flags |= RT_NORTREF;
 }
 #endif /* INET6 */
 
diff --git a/sys/net/route.h b/sys/net/route.h
index 1de222a06b1d..f12ed810d552 100644
--- a/sys/net/route.h
+++ b/sys/net/route.h
@@ -54,7 +54,8 @@ struct route {
 	struct	sockaddr ro_dst;
 };
 
-#define RT_CACHING_CONTEXT	0x1
+#define	RT_CACHING_CONTEXT	0x1	/* XXX: not used anywhere */
+#define	RT_NORTREF		0x2	/* doesn't hold reference on ro_rt */
 
 /*
  * These numbers are used by reliable protocols for determining
@@ -341,6 +342,18 @@ struct rt_addrinfo {
 	RTFREE_LOCKED(_rt);					\
 } while (0)
 
+#define	RO_RTFREE(_ro) do {					\
+	if ((_ro)->ro_rt) {					\
+		if ((_ro)->ro_flags & RT_NORTREF) {		\
+			(_ro)->ro_flags &= ~RT_NORTREF;		\
+			(_ro)->ro_rt = NULL;			\
+		} else {					\
+			RT_LOCK((_ro)->ro_rt);			\
+			RTFREE_LOCKED((_ro)->ro_rt);		\
+		}						\
+	}							\
+} while (0)
+
 struct radix_node_head *rt_tables_get_rnh(int, int);
 
 struct ifmultiaddr;