Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750750AbWIMQqm (ORCPT ); Wed, 13 Sep 2006 12:46:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750765AbWIMQqm (ORCPT ); Wed, 13 Sep 2006 12:46:42 -0400 Received: from e31.co.us.ibm.com ([32.97.110.149]:53476 "EHLO e31.co.us.ibm.com") by vger.kernel.org with ESMTP id S1750750AbWIMQqk (ORCPT ); Wed, 13 Sep 2006 12:46:40 -0400 In-Reply-To: <1158163943.15449.75.camel@dantu.rdu.redhat.com> To: Jeff Layton Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org MIME-Version: 1.0 Subject: Re: [PATCH] make ipv4 multicast packets only get delivered to sockets that are joined to group X-Mailer: Lotus Notes Release 7.0 HF144 February 01, 2006 Message-ID: From: David Stevens Date: Wed, 13 Sep 2006 09:42:11 -0700 X-MIMETrack: Serialize by Router on D03NM121/03/M/IBM(Release 7.0.1HF269 | June 22, 2006) at 09/13/2006 10:46:39, Serialize complete at 09/13/2006 10:46:39 Content-Type: text/plain; charset="US-ASCII" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1480 Lines: 31 Jeff Layton wrote on 09/13/2006 09:12:23 AM: > Most of the RFC's I've looked at don't seem to have much to say about > how multicasting works at the socket level. Is there an RFC or > specification that spells this out, or is this one of those situations > where things are somewhat open to interpretation? RFC's are standards for protocols and are concerned with interoperability among multiple implementations. They, in general, do not define API's (and those that do are "informational"). There are after-the-fact standards for sockets, including POSIX, but older features are effectively defined by industry practice; in this case, Deering's BSD implementation from nearly 20 years ago. Sections 7.1 & 7.2 of RFC 988 [Deering, 1986] hint at this interpretation (separation of membership from socket delivery), esp. when it says "Incoming multicast IP datagrams are delivered to upper-layer protocol modules using the same 'Receive IP' operation as normal, unicast datagrams." But Deering's own implementation, which does not distinguish which socket joined the group, is the source of the standard practice. +-DLS - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/