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authorEric Dumazet <edumazet@google.com>2012-10-04 05:25:26 +0400
committerDavid S. Miller <davem@davemloft.net>2012-10-04 21:58:26 +0400
commitf4ef85bbda96324785097356336bc79cdd37db0a (patch)
tree7a91ea1839d96ccb43d322f88a725f5a76b4be79 /include/net/ip_fib.h
parentc0b8b99287235626a5850ef7e5bfc842d1ebcecd (diff)
downloadlinux-f4ef85bbda96324785097356336bc79cdd37db0a.tar.xz
ipv4: add a fib_type to fib_info
commit d2d68ba9fe8 (ipv4: Cache input routes in fib_info nexthops.) introduced a regression for forwarding. This was hard to reproduce but the symptom was that packets were delivered to local host instead of being forwarded. David suggested to add fib_type to fib_info so that we dont inadvertently share same fib_info for different purposes. With help from Julian Anastasov who provided very helpful hints, reproduced here : <quote> Can it be a problem related to fib_info reuse from different routes. For example, when local IP address is created for subnet we have: broadcast 192.168.0.255 dev DEV proto kernel scope link src 192.168.0.1 192.168.0.0/24 dev DEV proto kernel scope link src 192.168.0.1 local 192.168.0.1 dev DEV proto kernel scope host src 192.168.0.1 The "dev DEV proto kernel scope link src 192.168.0.1" is a reused fib_info structure where we put cached routes. The result can be same fib_info for 192.168.0.255 and 192.168.0.0/24. RTN_BROADCAST is cached only for input routes. Incoming broadcast to 192.168.0.255 can be cached and can cause problems for traffic forwarded to 192.168.0.0/24. So, this patch should solve the problem because it separates the broadcast from unicast traffic. And the ip_route_input_slow caching will work for local and broadcast input routes (above routes 1 and 3) just because they differ in scope and use different fib_info. </quote> Many thanks to Chris Clayton for his patience and help. Reported-by: Chris Clayton <chris2553@googlemail.com> Bisected-by: Chris Clayton <chris2553@googlemail.com> Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Julian Anastasov <ja@ssi.bg> Tested-by: Chris Clayton <chris2553@googlemail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/ip_fib.h')
-rw-r--r--include/net/ip_fib.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 926142ed8d7a..9497be1ad4c0 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -102,6 +102,7 @@ struct fib_info {
unsigned char fib_dead;
unsigned char fib_protocol;
unsigned char fib_scope;
+ unsigned char fib_type;
__be32 fib_prefsrc;
u32 fib_priority;
u32 *fib_metrics;