Commit d547f727 authored Aug 07, 2011 by Julian Anastasov Committed by David S. Miller Aug 07, 2011

ipv4: fix the reusing of routing cache entries



	compare_keys and ip_route_input_common rely on
rt_oif for distinguishing of input and output routes
with same keys values. But sometimes the input route has
also same hash chain (keyed by iif != 0) with the output
routes (keyed by orig_oif=0). Problem visible if running
with small number of rhash_entries.

	Fix them to use rt_route_iif instead. By this way
input route can not be returned to users that request
output route.

	The patch fixes the ip_rt_bug errors that were
reported in ip_local_out context, mostly for 255.255.255.255
destinations.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 025890b4

net/ipv4/route.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -731,6 +731,7 @@ static inline int compare_keys(struct rtable rt1, struct rtable rt2)
		((__force u32)rt1->rt_key_src ^ (__force u32)rt2->rt_key_src) \|
		(rt1->rt_mark ^ rt2->rt_mark) \|
		(rt1->rt_key_tos ^ rt2->rt_key_tos) \|
		(rt1->rt_route_iif ^ rt2->rt_route_iif) \|
		(rt1->rt_oif ^ rt2->rt_oif) \|
		(rt1->rt_iif ^ rt2->rt_iif)) == 0;
		}
		@@ -2321,8 +2322,8 @@ int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
		if ((((__force u32)rth->rt_key_dst ^ (__force u32)daddr) \|
		((__force u32)rth->rt_key_src ^ (__force u32)saddr) \|
		(rth->rt_iif ^ iif) \|
		rth->rt_oif \|
		(rth->rt_key_tos ^ tos)) == 0 &&
		rt_is_input_route(rth) &&
		rth->rt_mark == skb->mark &&
		net_eq(dev_net(rth->dst.dev), net) &&
		!rt_is_expired(rth)) {

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