On Thu, Sep 12, 2019 at 9:16 PM Willem de Bruijn
<willemdebruijn.ker...@gmail.com> wrote:
>
> From: Willem de Bruijn <will...@google.com>
>
> UDP reuseport groups can hold a mix unconnected and connected sockets.
> Ensure that connections only receive all traffic to their 4-tuple.
>
> Fast reuseport returns on the first reuseport match on the assumption
> that all matches are equal. Only if connections are present, return to
> the previous behavior of scoring all sockets.
>
> Record if connections are present and if so (1) treat such connected
> sockets as an independent match from the group, (2) only return
> 2-tuple matches from reuseport and (3) do not return on the first
> 2-tuple reuseport match to allow for a higher scoring match later.
>
> New field has_conns is set without locks. No other fields in the
> bitmap are modified at runtime and the field is only ever set
> unconditionally, so an RMW cannot miss a change.
>
> Fixes: e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection")
> Link:
> http://lkml.kernel.org/r/ca+futsfrp09ajnyrt04ss6qj22viioewawmlawx0psk8-pg...@mail.gmail.com
> Signed-off-by: Willem de Bruijn <will...@google.com>
Slick, no additional cost for the BPF case and just a single branch
for the unconnected udp, tcp listener case!
Acked-by: Craig Gallek <kr...@google.com>
