From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965479Ab2CARFY (ORCPT ); Thu, 1 Mar 2012 12:05:24 -0500 Received: from bhuna.collabora.co.uk ([93.93.135.160]:53634 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758739Ab2CARFV (ORCPT ); Thu, 1 Mar 2012 12:05:21 -0500 Message-ID: <4F4FAC7E.2090604@collabora.co.uk> Date: Thu, 01 Mar 2012 18:06:06 +0100 From: Javier Martinez Canillas User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.1) Gecko/20120216 Thunderbird/10.0.1 MIME-Version: 1.0 To: Luiz Augusto von Dentz CC: Eric Dumazet , Rodrigo Moya , David Laight , David Miller , 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 Subject: Re: [PATCH 0/10] af_unix: add multicast and filtering features to AF_UNIX References: <1330606237.27405.5.camel@megeve> <1330606775.2465.56.camel@edumazet-laptop> <4F4F7FFB.6010608@collabora.co.uk> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/01/2012 05:02 PM, Luiz Augusto von Dentz wrote: > Hi Javier, > > On Thu, Mar 1, 2012 at 3:56 PM, Javier Martinez Canillas > wrote: >>> >>> Anyway, if you think multicast sockets is the way to go, then you could >>> setup a virtual network just to be able to use AF_INET multicast. >>> >>> Thats probably doable without kernel patching. >>> >> >> We could use AF_INET multicast on a local machine but we need some >> ordering and control flow requirements that are not guaranteed on UDP >> multicast over IP. That's why we thought to add a new address family >> AF_MCAST. > > I don't want to sound like a broken record, but Im afraid I have to, > what about Ancillary Messages, how you are going to support passing > fd? Actually the whole virtual network sounds like a bad idea, are we > going to give ips to each and every application connected to the bus, > actually it is necessary to have one virtual network for each bus. > > Contrary to someones believes I don't think AF_INET is that fast (e.g. > http://scottmoonen.com/2008/04/05/a-performance-comparison-of-af_unix-with-loopback-on-linux/) > > You are right. Ancillary messages are PF_UNIX specific and also some D-bus applications use fd passing for out-of-band communication. So, using multicast on AF_INET will break these applications. Regards, Javier