From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: Multicast IP packet routed between 2 ports nic on the same host Date: Mon, 06 Jun 2011 16:09:02 +0200 Message-ID: <1307369342.3098.26.camel@edumazet-laptop> References: <24665DDC0D7CF047BD6471A56E615EA628ABF4DE@CA-OPS-MAILBOX.miranda.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "netdev@vger.kernel.org" To: BONNEAU Guy Return-path: Received: from mail-wy0-f174.google.com ([74.125.82.174]:52588 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751164Ab1FFOJG (ORCPT ); Mon, 6 Jun 2011 10:09:06 -0400 Received: by wya21 with SMTP id 21so2813397wya.19 for ; Mon, 06 Jun 2011 07:09:04 -0700 (PDT) In-Reply-To: <24665DDC0D7CF047BD6471A56E615EA628ABF4DE@CA-OPS-MAILBOX.miranda.com> Sender: netdev-owner@vger.kernel.org List-ID: Le lundi 06 juin 2011 =C3=A0 13:40 +0000, BONNEAU Guy a =C3=A9crit : > I am trying to receive multicast data packets from a multicast router > to my Linux Ubuntu Desktop Workstation using kernel 2.6.35. The Linux > Desktop has an Intel 82576 dual NIC adapter. Each NIC is configured t= o > receive IP data from 2 different subnet. One is from 172.30.8.xx and > another one from 10.0.xx.xx. Multicast IP data can only be received > from 172.30.8.xx since there is no multicast source on subnet > 10.0.xx.xx and IT that administrates the subnet 10.0.xx.xx disabled > multicast capability of the switches and routers sitting on that > subnet. The subnet 172.30.8.xx has multicast source broadcasting on > multicast group 239.255.200.200:8000.=20 >=20 Hi Not clear if eth0 and eth1 are on both networks ? Please send us ip link ip addr ip ro Thanks > I am using the application mreceived (version 2.2) from : > http://www.cs.virginia.edu/~mngroup/software/ to test the network > multicast set-up and capability of my Ubuntu Desktop Workstation.=20 >=20 > I open a first console and I use mreceive to join multicast group > 239.255.200.200:8000 to receive multicast data from subnet 10.0.xx.xx > using the console command : ./mreceive -g 239.255.200.200 -p 8000 -i > 10.0.9.164 to the eth0 adapter of my workstation. The application is > idle and no multicast data is received. This is the expected > behaviour. >=20 > I open a second console and I use mreceive to join the same multicast > group 239.255.200.200:8000 to receive multicast data from subnet > 172.30.8.xx using the console command : ./mreceive -g 239.255.200.200 > -p 8000 -i 172.30.8.31 to the eth1 adapter of my workstation. The > application starts to receive multicast data and advertises the data > received. This is also the expected behaviour. >=20 > Now this is where the problem begins. As soon as the multicast data > begin to be received on the eth1 adapter the first console begins to > advertise multicast data received on eth0 adapter. I am well aware > that the Linux kernel implements a multicast level 2 routing > capability. Thus at first glance this seems to be the expected > behaviour. However... I have forwarding disabled as well as > mc_forwarding disabled and rp_filter is enabled for both adapters. > Thus I don't expect the kernel to forward the multicast data from eth= 1 > to eth0.=20 >=20 > I have recompiled the kernel with IP Multicast Routing disabled and > got the same behavior. I also tried kernel 2.6.38 and had the same > issue. >=20 > At this point I am inclined to think that the kernel multicast routin= g > might have an issue? I might have missing a network configuration > setting but at this point I am baffled. I checked the kernel bugbase > with the multicast tagging and couldn't find a filled bug regarding > this matter. The only remaining options for me are to fill a bug and > trace the kernel code (ipmr.c) to understand what going on. Can > someone shade light on this? Is this an expected behavior or an issue= ? >=20 > Thanks > GB=20 > =20