[ovs-dev] [PATCH 4/4] Tunnel: Snoop ingress packets and update neigh cache if needed.

Gaëtan Rivet grive at u256.net
Thu Nov 4 10:17:16 UTC 2021

On Tue, Nov 2, 2021, at 18:12, Paolo Valerio wrote:
> In case of native tunnel with bfd enabled, if the MAC address of the
> remote end's interface changes (e.g. because it got rebooted, and the
> MAC address is allocated dinamically), the BFD session will never be
> re-established.

typo: dynamically

> This happens because the local tunnel neigh entry doesn't get updated,
> and the local end keeps sending BFD packets with the old destination
> MAC address. This was not an issue until
> b23ddcc57d41 ("tnl-neigh-cache: tighten arp and nd snooping.")
> because ARP requests were snooped as well avoiding the problem.

I am not sure about perpetuating a BFD session when the tunnel line
protocol got down and changed dynamically. Is it a normal use-case
for BFD then?

But then updating the ARP/ND entries does not seem an issue in and of
itself. Code and tests looks good to me.

Acked-by: Gaetan Rivet <grive at u256.net>

Gaetan Rivet

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