Subject: Re: [PATCH net-next] udp: increment UDP_NO_PORTS when dropping unmatched multicasts

From: Rick Jones <[email-masked]>
Date: Wed, 01 Oct 2014 09:32:43 -0700

On 10/01/2014 08:54 AM, David L Stevens wrote:
> I think this would have the unpleasant side-effect of incrementing a drop
> stat when we have not joined a multicast group that has UDP traffic, but the
> interface is in promiscuous mode. Also, false positives for the multicast
> address filter.
>
> Multicast address filters are not perfect matches, so it is "normal" to receive
> multicasts and broadcasts that are not addressed to our host. I'm not sure those
> should count as "noports" any more than traffic addressed to someone else's IP
> address if we're in promiscuous mode should.
>
> In the multicast case, it would really only make sense if we have actually joined
> the group it's addressed to.

Do you think an "ignored" statistic would be appropriate then?

rick