From: Stefano Brivio <sbrivio@redhat.com>
To: David Miller <davem@davemloft.net>
Cc: Jianlin Shi <jishi@redhat.com>, Wei Wang <weiwan@google.com>,
David Ahern <dsahern@gmail.com>, Martin KaFai Lau <kafai@fb.com>,
Eric Dumazet <edumazet@google.com>,
Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>,
netdev@vger.kernel.org
Subject: [PATCH net-next v6 09/11] ip6_fib: Don't discard nodes with valid routing information in fib6_locate_1()
Date: Thu, 20 Jun 2019 01:59:49 +0200 [thread overview]
Message-ID: <32e5feb86ee8951074df71126122726eb3d7a949.1560987611.git.sbrivio@redhat.com> (raw)
In-Reply-To: <cover.1560987611.git.sbrivio@redhat.com>
When we perform an inexact match on FIB nodes via fib6_locate_1(), longer
prefixes will be preferred to shorter ones. However, it might happen that
a node, with higher fn_bit value than some other, has no valid routing
information.
In this case, we'll pick that node, but it will be discarded by the check
on RTN_RTINFO in fib6_locate(), and we might miss nodes with valid routing
information but with lower fn_bit value.
This is apparent when a routing exception is created for a default route:
# ip -6 route list
fc00:1::/64 dev veth_A-R1 proto kernel metric 256 pref medium
fc00:2::/64 dev veth_A-R2 proto kernel metric 256 pref medium
fc00:4::1 via fc00:2::2 dev veth_A-R2 metric 1024 pref medium
fe80::/64 dev veth_A-R1 proto kernel metric 256 pref medium
fe80::/64 dev veth_A-R2 proto kernel metric 256 pref medium
default via fc00:1::2 dev veth_A-R1 metric 1024 pref medium
# ip -6 route list cache
fc00:4::1 via fc00:2::2 dev veth_A-R2 metric 1024 expires 593sec mtu 1500 pref medium
fc00:3::1 via fc00:1::2 dev veth_A-R1 metric 1024 expires 593sec mtu 1500 pref medium
# ip -6 route flush cache # node for default route is discarded
Failed to send flush request: No such process
# ip -6 route list cache
fc00:3::1 via fc00:1::2 dev veth_A-R1 metric 1024 expires 586sec mtu 1500 pref medium
Check right away if the node has a RTN_RTINFO flag, before replacing the
'prev' pointer, that indicates the longest matching prefix found so far.
Fixes: 38fbeeeeccdb ("ipv6: prepare fib6_locate() for exception table")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
v6: Rebased onto net-next, no changes
v5: No changes
v4: No changes
v3: No changes
v2: No changes
net/ipv6/ip6_fib.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 92a6bde57594..8f36e6742c36 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1595,7 +1595,8 @@ static struct fib6_node *fib6_locate_1(struct fib6_node *root,
if (plen == fn->fn_bit)
return fn;
- prev = fn;
+ if (fn->fn_flags & RTN_RTINFO)
+ prev = fn;
next:
/*
--
2.20.1
next prev parent reply other threads:[~2019-06-20 0:00 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-19 23:59 [PATCH net-next v6 00/11] Fix listing (IPv4, IPv6) and flushing (IPv6) of cached route exceptions Stefano Brivio
2019-06-19 23:59 ` [PATCH net-next v6 01/11] fib_frontend, ip6_fib: Select routes or exceptions dump from RTM_F_CLONED Stefano Brivio
2019-06-19 23:59 ` [PATCH net-next v6 02/11] ipv4/fib_frontend: Allow RTM_F_CLONED flag to be used for filtering Stefano Brivio
2019-06-19 23:59 ` [PATCH net-next v6 03/11] ipv4/route: Allow NULL flowinfo in rt_fill_info() Stefano Brivio
2019-06-20 13:15 ` David Ahern
2019-06-20 19:00 ` Stefano Brivio
2019-06-19 23:59 ` [PATCH net-next v6 04/11] ipv4: Dump route exceptions if requested Stefano Brivio
2019-06-20 13:31 ` David Ahern
2019-06-20 19:01 ` Stefano Brivio
2019-06-20 19:21 ` David Ahern
2019-06-19 23:59 ` [PATCH net-next v6 05/11] Revert "net/ipv6: Bail early if user only wants cloned entries" Stefano Brivio
2019-06-19 23:59 ` [PATCH net-next v6 06/11] ipv6/route: Don't match on fc_nh_id if not set in ip6_route_del() Stefano Brivio
2019-06-20 14:16 ` David Ahern
2019-06-20 19:01 ` Stefano Brivio
2019-06-19 23:59 ` [PATCH net-next v6 07/11] ipv6/route: Change return code of rt6_dump_route() for partial node dumps Stefano Brivio
2019-06-20 14:17 ` David Ahern
2019-06-19 23:59 ` [PATCH net-next v6 08/11] ipv6: Dump route exceptions if requested Stefano Brivio
2019-06-20 14:24 ` David Ahern
2019-06-20 19:02 ` Stefano Brivio
2019-06-20 19:22 ` David Ahern
2019-06-19 23:59 ` Stefano Brivio [this message]
2019-06-19 23:59 ` [PATCH net-next v6 10/11] selftests: pmtu: Introduce list_flush_ipv4_exception test case Stefano Brivio
2019-06-19 23:59 ` [PATCH net-next v6 11/11] selftests: pmtu: Make list_flush_ipv6_exception test more demanding Stefano Brivio
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