ipv4: Delete routing cache.

The ipv4 routing cache is non-deterministic, performance wise, and is
subject to reasonably easy to launch denial of service attacks.

The routing cache works great for well behaved traffic, and the world
was a much friendlier place when the tradeoffs that led to the routing
cache's design were considered.

What it boils down to is that the performance of the routing cache is
a product of the traffic patterns seen by a system rather than being a
product of the contents of the routing tables.  The former of which is
controllable by external entitites.

Even for "well behaved" legitimate traffic, high volume sites can see
hit rates in the routing cache of only ~%10.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 1 deletions

diff --git a/include/net/route.h b/include/net/route.h
index ace3cb442519..5dcfeb621e06 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -109,7 +109,6 @@ extern struct ip_rt_acct __percpu *ip_rt_acct;
 struct in_device;
 extern int              ip_rt_init(void);
 extern void             rt_cache_flush(struct net *net, int how);
-extern void             rt_cache_flush_batch(struct net *net);
 extern struct rtable *__ip_route_output_key(struct net *, struct flowi4 *flp);
 extern struct rtable *ip_route_output_flow(struct net *, struct flowi4 *flp,
                                            struct sock *sk);