[Slirp] TCP keep-alive configuration

[Samuel Thibault]

Hello,

Sorry for the long delay, I wanted to have a closer look at such
tunables.

Ole Orhagen, le lun. 13 juin 2022 08:34:33 +0200, a ecrit:
> On Sat, Jun 11, 2022 at 10:24 PM Samuel Thibault <[1]
> samuel.thibault at ens-lyon.org> wrote:
> 
>     Ole Orhagen, le ven. 10 juin 2022 12:58:57 +0200, a ecrit:
>     > Hi, I see from the source code that TCP-keep alive parameters are
>     hard-coded in
>     > the source code.
> 
>     Yes, it's currently hardcoded. Making it tunable would be done by adding
>     a parameter in SlirpConfig.
> 
> Would this be a welcome contribution?

Yes! I'm thinking that it'd be useful to add altogether a few tunables,
to avoid multiplying the number of slirpconfig versions while adding
them one at a time.

What I could collect that could be tunable is this:

   LEASE_TIME
   TCP_SNDSPACE
   TCP_RCVSPACE
   TCPTV_* (maybe not all)

These could be added to SlirpConfig and Slirp, from which it can easily
be accessed from a struct socket or even a struct tcpcb (through
socket), to replace the use of the macros.

Samuel