Re: Any TCP VTW users?

[Simon Burge <simonb%NetBSD.org@localhost>]

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

Cheers,
Simon.