From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Denis V. Lunev" Subject: Re: [Devel] Re: [patch 0/2][NETNS49][IPV4][IGMP] activate multicast per namespace Date: Mon, 15 Oct 2007 12:31:50 +0400 Message-ID: <47132576.6020508@sw.ru> References: <20071012171013.105324992@mai.toulouse-stg.fr.ibm.com> <470FE130.8040403@fr.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <470FE130.8040403-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Daniel Lezcano Cc: containers-qjLDD68F18O7TbgM5vRIOg@public.gmane.org, "Eric W. Biederman" List-Id: containers.vger.kernel.org Daniel Lezcano wrote: > Eric W. Biederman wrote: >> Daniel Lezcano writes: >> >>> The following patches activate the multicast sockets for >>> the namespaces. The results is a traffic going through differents >>> namespaces. So if there are several applications >>> listenning to the same multicast group/port, running in >>> different namespaces, they will receive multicast packets. >> >> At a first glance this feels wrong. I don't see any per >> namespace filtering of multicast traffic. Unless the >> multicast traffic is routed/bridged between namespaces >> it should be possible to send multicast traffic in one >> namespace and listen for that same traffic in another >> namespace and not get it. > > The described behavior is the case were the namespaces are communicating > via veth like: > > eth0 > | > | ------------- nsA > veth0 <--|--> veth1 | > | ------------- > | > | -------------nsB > veth2 <--|--> veth3 | > ------------- > > > If an application is listening in nsA and nsB. And if in nsA, an > application sends multicast traffic, both will receive the packets > because they are routed by the pair device. > As you said this is the correct behavior, if we have two machines hostA > and hostB in the same network and both are listening on the multicast > address and if an application on hostA send multicast packets, both > should receive the multicast packets. > If the traffic is not routed, multicast will not pass through the > namespaces. > > The description I gave in the patchset introduction was to describe such > behavior which is, IMHO, important for inter-container communication. > Perhaps, I should have not gave this description which seems to sow > confusion in mind, sorry for that. > > Anyway, I hope the patchset is ok :) hmm, by the way, will this work with macvlan? also, I am dumb with multicasts :) who will clone the packet if there are more than one namespace listen and there are some listeners behind ethernet? Regards, Den