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| author | Eric Dumazet <edumazet@google.com> | 2012-10-04 01:25:26 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-10-04 13:58:26 -0400 |
| commit | f4ef85bbda96324785097356336bc79cdd37db0a (patch) | |
| tree | 7a91ea1839d96ccb43d322f88a725f5a76b4be79 /net | |
| parent | c0b8b99287235626a5850ef7e5bfc842d1ebcecd (diff) | |
| download | linux-3.10-f4ef85bbda96324785097356336bc79cdd37db0a.tar.gz linux-3.10-f4ef85bbda96324785097356336bc79cdd37db0a.tar.bz2 linux-3.10-f4ef85bbda96324785097356336bc79cdd37db0a.zip | |
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 'net')
| -rw-r--r-- | net/ipv4/fib_semantics.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index 3509065e409..267753060ff 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -314,6 +314,7 @@ static struct fib_info *fib_find_info(const struct fib_info *nfi) 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 fib_config *cfg) 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) { |