From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Lamparter Subject: Re: [PATCH 0/10] af_unix: add multicast and filtering features to AF_UNIX Date: Mon, 5 Mar 2012 19:55:03 +0100 Message-ID: <20120305185502.GF3119316@jupiter.n2.diac24.net> References: <20120301.170848.432407217191581288.davem@davemloft.net> <20120302.035509.1994457175982020283.davem@davemloft.net> <4F509274.9060302@collabora.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Miller , shemminger@vyatta.com, ying.xue@windriver.com, luiz.dentz@gmail.com, eric.dumazet@gmail.com, rodrigo.moya@collabora.co.uk, javier@collabora.co.uk, lennart@poettering.net, kay.sievers@vrfy.org, alban.crequy@collabora.co.uk, bart.cerneels@collabora.co.uk, sjoerd.simons@collabora.co.uk, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Javier Martinez Canillas Return-path: Received: from spaceboyz.net ([87.106.131.203]:33883 "EHLO spaceboyz.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757336Ab2CESzW (ORCPT ); Mon, 5 Mar 2012 13:55:22 -0500 Content-Disposition: inline In-Reply-To: <4F509274.9060302@collabora.co.uk> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, Mar 02, 2012 at 10:27:16AM +0100, Javier Martinez Canillas wrote: > Do you think that a simpler AF_UNIX multicast implementation without the > locking to guarantee order delivery and the flow control that blocks the > sender can be resend to you to reconsider merging it? I still don't get how blocking the sender when the receiver doesn't empty his socket queue can possibly ever be a good idea. All I see is a very nice way to choke the entire D-Bus from one malicious or broken app. Note that originally we were talking about blocking delivery for _multicast_. In that case you can't even poll on writability on a granularity finer than group level. Yet, this still comes up here and there as a requirement for IPC mechanisms to back D-Bus. When the buffers at the receiver are fully filled, IMHO that's the point to cut off the client. If this becomes an issue, the buffers can be increased in size, but at some point it's a sign that you're using D-Bus for too much? -David