From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [91.216.245.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 332DE3655C4; Tue, 9 Jun 2026 22:25:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.216.245.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781043936; cv=none; b=CffND7Ufgr/4kBvrv3zp10bAjEWJGg12UpnEa3sR9d/ThErU3Tspyfu2Qs+AsgiO/7uuFh9NlhnG6FCiIF0ThK1kw/KATzLNJ61CjTUhzx7WLFA6qslr6/8KFlMhmfesFQIVbTzmoAR198F7Kjus8C+WOBSHvKKkDcSgpK+chTo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781043936; c=relaxed/simple; bh=wxdEyR0Jsul6J54VQA36KmH/WMKdRF/uqmzrtbVrmq4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ADgzC9iUe/Y7Tzk4/ixa67l47W9vurQN2vnUdFUTB3qfN/GY5MhSI4bOwZjfXyt77YYrX0qZkR+FRyyiY2qt58kc3e+eowRZJG8g826EoNzw53F8o4zW5MITshhe66CrHKRccrqN9jhu8/UjtP3omRg2uJ+4lJsDNEFBja5NlDo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de; spf=pass smtp.mailfrom=strlen.de; arc=none smtp.client-ip=91.216.245.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=strlen.de Received: by Chamillionaire.breakpoint.cc (Postfix, from userid 1003) id EF70F60C94; Wed, 10 Jun 2026 00:25:31 +0200 (CEST) Date: Wed, 10 Jun 2026 00:25:30 +0200 From: Florian Westphal To: Jakub Kicinski Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org Subject: Re: [PATCH net-next] net: dummy: add phony ndo_setup_tc stub Message-ID: References: <20260609142813.9197-1-fw@strlen.de> <20260609151517.186b1cac@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260609151517.186b1cac@kernel.org> Jakub Kicinski wrote: > On Tue, 9 Jun 2026 16:28:09 +0200 Florian Westphal wrote: > > Unlike netdevsim, dummy is a data sink so no capabilities (e.g. > > u32-style matcher, vport device redirects, PPPoE header push/pop etc). > > have to be implemented. > > If no "peer" is configured netdevsim is also a data sink. Yes, but you can configure peers. And then this fake offload stub is a liar. I would expect that offloads for netdevsim actually work, i.e. that a shaper shapes, that ets offload does delay packets and in case of flowtable that it will move skbs from one vport to another (if that was requested). > We added netdevsim because dummy and veth started accumulating > "features" which were clearly just for test harnesses. Would be > great if we could stay the course and put whatever changes you > need in netdevsim, even if it requires some hacks. Is a lot more work. I don't have time ATM to implement a u32-style packet matcher or a fake software flowtable. > Is there anything fundamentally blocking the use of netdevsim? > Or is it just convenience (since netdevsim is a bit of a PITA > to create and establish the name of)? I played with netdevsim, aside from the above (i.e., I don't expect netdevsim to say 'offloaded' and then ignore all the offloaded commands...) the worst part is the naming and the behaviour when creating new devices while in a network namespace. Test is spawned via 'unshare -n' -- I did not find a way to really extract the new device name reliably except via 'ip link'. I think thats solveable, so yes, I could make netdevsim lie instead. But I don't think its the right thing to do. If you disagree and think that this is fine I can retarget this to netdevsim, no problem.