From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?utf-8?Q?Ludovic_Court=C3=A8s?= <ludo@gnu.org>
Subject: Re: SSHv2 doesn't actually have compression levels
Date: Fri, 23 Aug 2019 14:21:18 +0200
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In-Reply-To: <877e746et0.fsf@nckx> (Tobias Geerinckx-Rice's message of "Fri,
 23 Aug 2019 00:00:43 +0200")
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To: Tobias Geerinckx-Rice <me@tobias.gr>
Cc: guix-devel <guix-devel@gnu.org>

Tobias Geerinckx-Rice <me@tobias.gr> skribis:

> Ludo',
>
> Welcome back :-)
>
> Ludovic Court=C3=A8s =E5=86=99=E9=81=93=EF=BC=9A
>> I don=E2=80=99t get it: the =E2=80=98compression-level=E2=80=99 field de=
faults to 3, and
>> OpenSSH
>> does:
>>
>>   static int
>>   start_compression_out(struct ssh *ssh, int level)
>>   {
>>           if (level < 1 || level > 9)
>>                   return SSH_ERR_INVALID_ARGUMENT;
>>           debug("Enabling compression at level %d.", level);
>>
>>   [...]
>>
>>   }
>>
>> What=E2=80=99s wrong?
>
> Exactly!

Exactly what?  :-)

>  ~/openssh-8.0p1 =CE=BB grep -r start_compression_out
>  packet.c:start_compression_out(struct ssh *ssh, int level)
>  packet.c:	if ((r =3D start_compression_out(ssh, 6)) !=3D 0)

libssh (which is what =E2=80=98guix offload=E2=80=99 uses) appears to honor=
 the
user-provided compression level:

--8<---------------cut here---------------start------------->8---
int compress_buffer(ssh_session session, ssh_buffer buf) {
  ssh_buffer dest =3D NULL;

  dest =3D gzip_compress(session, buf, session->opts.compressionlevel);
--8<---------------cut here---------------end--------------->8---

Apologies if I=E2=80=99m missing the obvious!

Thanks,
Ludo=E2=80=99.