From: Hannes Frederic Sowa <hannes@stressinduktion.org>
To: Salam Noureddine <noureddine@aristanetworks.com>,
"David S. Miller" <davem@davemloft.net>,
Daniel Borkmann <dborkman@redhat.com>,
Willem de Bruijn <willemb@google.com>, Phil Sutter <phil@nwl.cc>,
Eric Dumazet <edumazet@google.com>,
netdev@vger.kernel.org
Subject: Re: Issue with gratuitous arps when new addr is different from cached addr
Date: Thu, 21 Nov 2013 07:26:35 +0100 [thread overview]
Message-ID: <20131121062635.GD4347@order.stressinduktion.org> (raw)
In-Reply-To: <20131121062349.GC4347@order.stressinduktion.org>
On Thu, Nov 21, 2013 at 07:23:49AM +0100, Hannes Frederic Sowa wrote:
> On Wed, Nov 20, 2013 at 10:06:34PM -0800, Salam Noureddine wrote:
> > Isn't locktime useful in that case for limiting the rate of garp
> > changes to the arp cache?
>
> Yes, as I said, it would be nice to have rate-limiting for those, too.
>
> GARP is used in cluster setups to make the switch-over as fast as possible and
> I don't think they accept those lock-down delays, so I guess it would be nice
> to forceful override the lladdr if (sip == tip) && ACCEPT_ARP(dev) is true in
> every case.
>
> I guess you are not testing with ACCEPT_ARP?
>
> In that case I am not sure what to do.
>
> override = (...timing...) || sip == tip; could work but does relax the
> protection of the neigh cache.
>
> In IPv6 we have a flag in the packet if we should overwrite the entry.
>
> I'll have to think about that a bit more. Could well be the case that we need
> your proposal, too. But then we would have to validate the change with IPv6,
> too and neighbour cache states are really complex.
Hmm, could it help to bring the neighbor to suspect state (== WEAK_OVERRIDE)?
next prev parent reply other threads:[~2013-11-21 6:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-21 0:40 Issue with gratuitous arps when new addr is different from cached addr Salam Noureddine
2013-11-21 4:40 ` Hannes Frederic Sowa
2013-11-21 6:06 ` Salam Noureddine
2013-11-21 6:23 ` Hannes Frederic Sowa
2013-11-21 6:26 ` Hannes Frederic Sowa [this message]
2013-11-21 6:33 ` Salam Noureddine
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