From: Ido Schimmel <idosch@idosch•org>
To: Hangbin Liu <liuhangbin@gmail•com>
Cc: netdev@vger•kernel.org, "David S . Miller" <davem@davemloft•net>,
David Ahern <dsahern@kernel•org>,
Eric Dumazet <edumazet@google•com>,
Jakub Kicinski <kuba@kernel•org>, Paolo Abeni <pabeni@redhat•com>,
Thomas Haller <thaller@redhat•com>
Subject: Re: [PATCHv6 net-next 1/2] ipv6: do not match device when remove source route
Date: Thu, 17 Aug 2023 15:02:07 +0300 [thread overview]
Message-ID: <ZN4MP+9wi5w9AL7h@shredder> (raw)
In-Reply-To: <20230816060724.1398842-2-liuhangbin@gmail.com>
On Wed, Aug 16, 2023 at 02:07:23PM +0800, Hangbin Liu wrote:
> After deleting an IPv6 address on an interface and cleaning up the
> related preferred source entries, it is important to ensure that all
> routes associated with the deleted address are properly cleared. The
> current implementation of rt6_remove_prefsrc() only checks the preferred
> source addresses bound to the current device. However, there may be
> routes that are bound to other devices but still utilize the same
> preferred source address.
>
> To address this issue, it is necessary to also delete entries that are
> bound to other interfaces but share the same source address with the
> current device. Failure to delete these entries would leave routes that
> are bound to the deleted address unclear. Here is an example reproducer
> (I have omitted unrelated routes):
>
> + ip link add dummy1 type dummy
> + ip link add dummy2 type dummy
> + ip link set dummy1 up
> + ip link set dummy2 up
> + ip addr add 1:2:3:4::5/64 dev dummy1
> + ip route add 7:7:7:0::1 dev dummy1 src 1:2:3:4::5
> + ip route add 7:7:7:0::2 dev dummy2 src 1:2:3:4::5
> + ip -6 route show
> 1:2:3:4::/64 dev dummy1 proto kernel metric 256 pref medium
> 7:7:7::1 dev dummy1 src 1:2:3:4::5 metric 1024 pref medium
> 7:7:7::2 dev dummy2 src 1:2:3:4::5 metric 1024 pref medium
> + ip addr del 1:2:3:4::5/64 dev dummy1
> + ip -6 route show
> 7:7:7::1 dev dummy1 metric 1024 pref medium
> 7:7:7::2 dev dummy2 src 1:2:3:4::5 metric 1024 pref medium
>
> As Ido reminds, in IPv6, the preferred source address is looked up in
> the same VRF as the first nexthop device, which is different with IPv4.
> So, while removing the device checking, we also need to add an
> ipv6_chk_addr() check to make sure the address does not exist on the other
> devices of the rt nexthop device's VRF.
>
> After fix:
> + ip addr del 1:2:3:4::5/64 dev dummy1
> + ip -6 route show
> 7:7:7::1 dev dummy1 metric 1024 pref medium
> 7:7:7::2 dev dummy2 metric 1024 pref medium
>
> Reported-by: Thomas Haller <thaller@redhat•com>
> Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2170513
> Fixes: c3968a857a6b ("ipv6: RTA_PREFSRC support for ipv6 route source address selection")
> Signed-off-by: Hangbin Liu <liuhangbin@gmail•com>
Reviewed-by: Ido Schimmel <idosch@nvidia•com>
But I suggest removing the Fixes tag given the patch is targeted at
net-next and does not fix a regression (never worked).
next prev parent reply other threads:[~2023-08-17 12:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-16 6:07 [PATCHv6 net-next 0/2] ipv6: update route when delete source address Hangbin Liu
2023-08-16 6:07 ` [PATCHv6 net-next 1/2] ipv6: do not match device when remove source route Hangbin Liu
2023-08-17 12:02 ` Ido Schimmel [this message]
2023-08-16 6:07 ` [PATCHv6 net-next 2/2] selftests: fib_test: add a test case for IPv6 source address delete Hangbin Liu
2023-08-17 12:57 ` Ido Schimmel
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