From: David Ahern <dsahern@gmail.com>
To: Wei Wang <weiwan@google.com>, David Ahern <dsahern@kernel.org>
Cc: "David S . Miller" <davem@davemloft.net>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
Martin KaFai Lau <kafai@fb.com>
Subject: Re: [PATCH net-next] ipv6: Convert gateway validation to use fib6_info
Date: Fri, 21 Jun 2019 15:04:42 -0600 [thread overview]
Message-ID: <5b43374f-bcc4-bb58-ae61-b0f191330f20@gmail.com> (raw)
In-Reply-To: <CAEA6p_BUSFUCJJ_WsAAM2JRhQBBHjUepNZPpFX6DrTSCancD_g@mail.gmail.com>
On 6/20/19 5:43 PM, Wei Wang wrote:
> I am not very convinced that fib6_lookup() could be equivalent to
> rt6_lookup(). Specifically, rt6_lookup() calls rt6_device_match()
> while fib6_lookup() calls rt6_select() to match the oif. From a brief
> glance, it does seem to be similar, especially considering that saddr
> is NULL. So it probably is OK?
When you remove the rt6_check_neigh call since RT6_LOOKUP_F_REACHABLE is
not set that removes the RT6_NUD_FAIL_DO_RR return and round-robin
logic. I am reasonably confident that given the use case - validate the
gateway and optionally given the device - it is the same.
rt6_select is much more complicated than rt6_device_match, so there is a
small possibility that in some corner case gateway validation fails /
succeeds with fib6_table_lookup where it would succeed / fail with
ip6_pol_route_lookup. But, ip6_pol_route and fib6_table_lookup is the
code path actually used for packet Rx and Tx, so it seems to me to be
the more proper one for gateway validation.
I will send a v2 with idev change you mentioned.
prev parent reply other threads:[~2019-06-21 21:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-20 19:05 [PATCH net-next] ipv6: Convert gateway validation to use fib6_info David Ahern
2019-06-20 23:43 ` Wei Wang
2019-06-21 0:52 ` David Ahern
2019-06-21 21:04 ` David Ahern [this message]
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