linux/net/ipv4
Eric Dumazet f4ef85bbda ipv4: add a fib_type to fib_info
commit d2d68ba9fe (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>
2012-10-04 13:58:26 -04:00
..
netfilter
af_inet.c
ah4.c
arp.c
cipso_ipv4.c
datagram.c
devinet.c
esp4.c
fib_frontend.c
fib_lookup.h
fib_rules.c
fib_semantics.c ipv4: add a fib_type to fib_info 2012-10-04 13:58:26 -04:00
fib_trie.c
gre.c
icmp.c
igmp.c
inet_connection_sock.c
inet_diag.c
inet_fragment.c
inet_hashtables.c
inet_lro.c
inet_timewait_sock.c
inetpeer.c
ip_forward.c
ip_fragment.c
ip_gre.c
ip_input.c
ip_options.c
ip_output.c
ip_sockglue.c
ip_vti.c
ipcomp.c
ipconfig.c
ipip.c
ipmr.c
Kconfig
Makefile
netfilter.c
ping.c
proc.c
protocol.c
raw.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-10-02 11:11:09 -07:00
route.c
syncookies.c
sysctl_net_ipv4.c
tcp_bic.c
tcp_cong.c
tcp_cubic.c
tcp_diag.c
tcp_fastopen.c
tcp_highspeed.c
tcp_htcp.c
tcp_hybla.c
tcp_illinois.c
tcp_input.c
tcp_ipv4.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-10-02 11:11:09 -07:00
tcp_lp.c
tcp_memcontrol.c
tcp_metrics.c
tcp_minisocks.c
tcp_output.c
tcp_probe.c
tcp_scalable.c
tcp_timer.c
tcp_vegas.c
tcp_vegas.h
tcp_veno.c
tcp_westwood.c
tcp_yeah.c
tcp.c
tunnel4.c
udp_diag.c
udp_impl.h
udp.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-10-02 11:11:09 -07:00
udplite.c
xfrm4_input.c
xfrm4_mode_beet.c
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c
xfrm4_output.c
xfrm4_policy.c
xfrm4_state.c
xfrm4_tunnel.c