From mboxrd@z Thu Jan 1 00:00:00 1970 From: "=?iso-8859-15?q?R=E9mi?= Denis-Courmont" Subject: Re: [PATCH 7/9] AF_UNIX: Documentation on multicast Unix Sockets Date: Mon, 22 Nov 2010 21:07:40 +0200 Message-ID: <201011222107.41548.remi@remlab.net> References: <20101122183447.124afce5@chocolatine.cbg.collabora.co.uk> <1290450982-17480-7-git-send-email-alban.crequy@collabora.co.uk> Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-15 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-kernel@vger.kernel.org To: Alban Crequy , netdev@vger.kernel.org Return-path: Received: from yop.chewa.net ([91.121.105.214]:51674 "EHLO yop.chewa.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753280Ab0KVTHo convert rfc822-to-8bit (ORCPT ); Mon, 22 Nov 2010 14:07:44 -0500 In-Reply-To: <1290450982-17480-7-git-send-email-alban.crequy@collabora.co.uk> Sender: netdev-owner@vger.kernel.org List-ID: Le lundi 22 novembre 2010 20:36:20 Alban Crequy, vous avez =E9crit : > +Multicast Unix sockets > +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > + > +Multicast group memberships are stored in struct unix_mcast nodes. A= n Unix > +socket can join several multicast groups. Struct unix_mcast nodes ar= e > doubly +linked: > +- In (struct unix_sock)->mcast_subscriptions > +- In (struct unix_sock)->mcast_members I may be stupid, but I found this whole documentation very confusing, a= nd so=20 the API it tries to describe. Traditionally: - Senders may or not may be part of the group and are not kept track of= =2E - Receivers join to the group then receive message sent to it. - Loopback defines whether a sender receives its own echo if it sends t= o a group that it has joined. - If connected to a multicast group, messages from the socket are route= d to=20 the group (in absence of a contradictoy socket address). This has no ef= fect on=20 membership to the multicast group under any circumstance. You cannot 'listen' or 'accept' on a multicast group. So I am not entirely clear what semantics your patchset is following. B= ut it=20 does not seem like "multicast" to me and therefore seems not very well=20 documented :-( --=20 R=E9mi Denis-Courmont http://www.remlab.net/ http://fi.linkedin.com/in/remidenis