From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH net-next 2/3] tuntap: allow overriding ethtool driver info Date: Thu, 25 Jul 2013 14:56:08 -0700 Message-ID: <20130725145608.3c123a9a@nehalam.linuxnetplumber.net> References: <20130724161156.4a8cf02b@nehalam.linuxnetplumber.net> <20130724161325.38404ed3@nehalam.linuxnetplumber.net> <1374709687.1732.46.camel@bwh-desktop.uk.level5networks.com> <20130724171617.53a48d24@nehalam.linuxnetplumber.net> <1374787157.3058.28.camel@bwh-desktop.uk.level5networks.com> <20130725143206.03f4975a@nehalam.linuxnetplumber.net> <1374788182.3058.32.camel@bwh-desktop.uk.level5networks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Helmut Grohne , David Miller , To: Ben Hutchings Return-path: Received: from mail-pd0-f174.google.com ([209.85.192.174]:53519 "EHLO mail-pd0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754001Ab3GYV4L (ORCPT ); Thu, 25 Jul 2013 17:56:11 -0400 Received: by mail-pd0-f174.google.com with SMTP id 3so1133896pdj.5 for ; Thu, 25 Jul 2013 14:56:10 -0700 (PDT) In-Reply-To: <1374788182.3058.32.camel@bwh-desktop.uk.level5networks.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 25 Jul 2013 22:36:22 +0100 Ben Hutchings wrote: > On Thu, 2013-07-25 at 14:32 -0700, Stephen Hemminger wrote: > > On Thu, 25 Jul 2013 22:19:17 +0100 > > Ben Hutchings wrote: > > > > > On Wed, 2013-07-24 at 17:16 -0700, Stephen Hemminger wrote: > > > > On Thu, 25 Jul 2013 00:48:07 +0100 > > > > Ben Hutchings wrote: > > > > > > > > > On Wed, 2013-07-24 at 16:13 -0700, Stephen Hemminger wrote: > > > > > > This patch adds new ioctl to allow setting the ethtool information > > > > > > returned by the TUN device. This is useful when using tun device as a surrogate > > > > > > for hardware or other software emulation. > > > > > > > > > > I don't like this idea. Which tools are you trying to fool? How does > > > > > this work when you don't implement any driver-specific behaviour (e.g. > > > > > SIOCDEVPRIVATE) they expect? > > > > > > > > We use surrogate interfaces in user mode application and want to > > > > display different information for these than the normal TUN device. > > > > > > What is the problem that can't be solved purely in userland? > > > > > > Ben. > > > > > > > There applications (like SNMP) that use ethtool info. > > Huh, I never expected they would record the driver and version. So you > want them to report the userland software name and version? I can sort > of see how this might be useful as part of a test harness, but I would > hate to see this get used in production. Users ought to be able to > trust that 'ethtool -i' shows them the kernel driver information. > > Ben. > It is more the bus info. The user mode driver knows the PCI address of the device it is controlling.