3.6-stable review patch. If anyone has any objections, please let me know.
------------------ From: Eric Dumazet <[email protected]> [ Upstream commit f4ef85bbda96324785097356336bc79cdd37db0a ] 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 <[email protected]> Bisected-by: Chris Clayton <[email protected]> Reported-by: Dave Jones <[email protected]> Signed-off-by: Eric Dumazet <[email protected]> Cc: Julian Anastasov <[email protected]> Tested-by: Chris Clayton <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- include/net/ip_fib.h | 1 + net/ipv4/fib_semantics.c | 2 ++ 2 files changed, 3 insertions(+) --- 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; --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -314,6 +314,7 @@ static struct fib_info *fib_find_info(co nfi->fib_scope == fi->fib_scope && nfi->fib_prefsrc == fi->fib_prefsrc && nfi->fib_priority == fi->fib_priority && + nfi->fib_type == fi->fib_type && memcmp(nfi->fib_metrics, fi->fib_metrics, sizeof(u32) * RTAX_MAX) == 0 && ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 && @@ -833,6 +834,7 @@ struct fib_info *fib_create_info(struct fi->fib_flags = cfg->fc_flags; fi->fib_priority = cfg->fc_priority; fi->fib_prefsrc = cfg->fc_prefsrc; + fi->fib_type = cfg->fc_type; fi->fib_nhs = nhs; change_nexthops(fi) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
