From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tobias Geerinckx-Rice Subject: SSHv2 doesn't actually have compression levels Date: Tue, 30 Jul 2019 03:58:32 +0200 Message-ID: <87ef28fflj.fsf@nckx> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" Return-path: Received: from eggs.gnu.org ([2001:470:142:3::10]:43247) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsHPT-0000P7-0q for guix-devel@gnu.org; Mon, 29 Jul 2019 21:58:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hsHPR-0001Sm-Sf for guix-devel@gnu.org; Mon, 29 Jul 2019 21:58:38 -0400 Received: from tobias.gr ([2001:470:7405::1]:41544) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hsHPR-0001Qc-9u for guix-devel@gnu.org; Mon, 29 Jul 2019 21:58:37 -0400 Received: by tobias.gr (OpenSMTPD) with ESMTP id 4c8f9ea9 for ; Tue, 30 Jul 2019 01:58:34 +0000 (UTC) Received: by submission.tobias.gr (OpenSMTPD) with ESMTPSA id 8f797798 (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256:NO) for ; Tue, 30 Jul 2019 01:58:34 +0000 (UTC) List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Sender: "Guix-devel" To: guix-devel --=-=-= Content-Type: text/plain; format=flowed Guix, While reading (guix scripts offload) in a (failed) attempt to get offloading working, the following comment caught my eye: ;; We rely on protocol-level compression from libssh to optimize large data ;; transfers. Warn if it's missing. which means that we're not currently doing our own compression inside the tunnel. This is significant, because it means that the COMPRESS-LEVEL field of BUILD-MACHINE is completely bogus[0], and probably always was - unless it once supported SSHv1, which I think we can agree is not something we want to support today. Nobody's offloading libreoffice to that old router in the attic. I'd like to undocument the option, and add a comment noting its lack of any useful effect to the code, by next week. Kind regards, T G-R [0]: Take a look at OpenSSH's readconf.c, packet.c, and all calls to start_compression_out(). --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEARYKAB0WIQT12iAyS4c9C3o4dnINsP+IT1VteQUCXT+kSQAKCRANsP+IT1Vt eQd+AQDKvBKvMiOVaGJOFQaLKiP8wmuK+xHlW4OOCpIKvL8kkAEA/eoH/wpTNYHr 8PuFkidT07t+dSqFLxhS8A8EnYsYBwk= =EmdC -----END PGP SIGNATURE----- --=-=-=--