Re: Any TCP VTW users?

[Ryota Ozaki <ozaki-r%netbsd.org@localhost>]

On Fri, Sep 16, 2022 at 10:21 AM Simon Burge <simonb%netbsd.org@localhost> wrote:
>
> Ryota Ozaki wrote:
>
> > Hi,
> >
> > Are there any users of TCP Vestigial Time-Wait (VTW)?
> > The feature is disabled by default and we need to explicitly
> > enable via sysctl to use it.
> >
> > I just want to know if we should still maintain it.
>
> I wouldn't be unhappy if it just disappeared.  It's totally
> undocumented, and will also cause a panic on archs with larger cache
> line size because it does some really funky incorrect math that I
> stared at for a while then gave up on.
>
> erlite# sysctl -w net.inet.tcp.vtw.enable=1
> 15293.7939168] panic: kernel diagnostic assertion "n <= FATP_MAX / 2" failed: file "../../../../netinet/tcp_vtw.c", line 218

Oh, that's bad...  Thank you for telling me.

  ozaki-r