From f4ef85bbda96324785097356336bc79cdd37db0a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 4 Oct 2012 01:25:26 +0000 Subject: 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 : 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. Many thanks to Chris Clayton for his patience and help. Reported-by: Chris Clayton Bisected-by: Chris Clayton Reported-by: Dave Jones Signed-off-by: Eric Dumazet Cc: Julian Anastasov Tested-by: Chris Clayton Signed-off-by: David S. Miller --- include/net/ip_fib.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net/ip_fib.h') 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; -- cgit v1.2.3