On Fri, Sep 05, 2025 at 10:11:46PM -0400, Jon Maloy wrote:
> We add a cache table to keep partial contents of the kernel ARP/NDP
> tables. This way, we drastically reduce the number of netlink calls
> to read those tables.
> 
> We create placeholder cache entries representing non- or not-yet-
> existing ARP/NDP entries when needed. We add a short expiration time
> to each such entry, so that we can know when to make repeated calls to
> the kernel tables in the beginning. We also add an access counter to the
> entries, to ensure that the timer becomes longer and the call frequency
> abates over time if no ARP/NDP entry shows up.
> 
> For regular entries we use a much longer timer, with the purpose to
> update the entry in the rare case that a remote host changes its
> MAC address.
> 
> Signed-off-by: Jon Maloy <jmaloy@redhat.com>

Sorry, another patch reminded me of something I missed on the first pass:

[snip]

> +static struct mac_cache_table mac_cache;
> +const uint8_t undefined_mac[6] = {0, 0, 0, 0, 0, 0};

We already have MAC_ZERO in util.h.

-- 
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