From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gertjan Hofman Subject: Re: VLAN and ARP failure on tg3 drivers Date: Sun, 25 Oct 2009 21:30:09 -0700 (PDT) Message-ID: <477963.52849.qm@web32605.mail.mud.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "netdev@vger.kernel.org" , Eric Dumazet , Benny Amorsen To: Matt Carlson Return-path: Received: from web32605.mail.mud.yahoo.com ([68.142.207.232]:24862 "HELO web32605.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751924AbZJZEaF convert rfc822-to-8bit (ORCPT ); Mon, 26 Oct 2009 00:30:05 -0400 Sender: netdev-owner@vger.kernel.org List-ID: Dear Matt, Eric, Benny, Sorry about the slow response to your fast replies. I think Benny is co= rrect, the 'problem' lies in the fact that we were using a VLAN ID of 0= , without knowing its special significance. User error. I tested it with other VLAN id's (>0) and it appears to work fine. We a= re not entirely sure we understand=A0 why it used to work with VLAN ID = 0 on the Broadcom chips and still does with a number of different cards= (with >2.6.27 kernels).=A0 What is the 'correct' behaviour for this in= correct usage ? When a PC returns the ARP response to the machine with = the BroadCom card, it will have the destination address of the VLAN dev= ice, but presumably the VLAN ID tag set to zero.=A0 Hmmm. I can live wi= th not knowing the answer I guess. Thanks again, Gertjan =20 --- On Fri, 10/23/09, Matt Carlson wrote: > From: Matt Carlson > Subject: Re: VLAN and ARP failure on tg3 drivers > To: "Gertjan Hofman" > Cc: "netdev@vger.kernel.org" > Date: Friday, October 23, 2009, 3:35 PM > On Thu, Oct 22, 2009 at 09:52:42PM > -0700, Gertjan Hofman wrote: > > Dear Kernel developers, > >=20 > > A couple of weeks ago we tried to migrate from a > 2.6.24? kernel to a 2.6.29 kernel and noticed our VLAN > application no longer works.? The problem is easy to > replicate: > >=20 > > 1. connect 2 PC's with a cross-over cable > > 2. set up a fixed IP address to both PC's? (say > 192.168.0.[1,2]) > > 3. create a vlan:? vconfig? add eth0 0. > > 4. set IP addresses on the VLAN devices? (say > 192.168.1.[1,2]) > > 5. try ping one machine from the other. > >=20 > > I tried to dig into the problem by using un-patched > kernel.org kernels with Ubuntu .config files.? Kernels up to > 2.6.26 work fine, kernels after and including 2.6.27 fail. > The problem is that ARP messages are being dropped. If the > ARP table is updated by hand on each machine, the > communication across the VLAN works fine. > >=20 > > At first I thought the kernel VLAN code was the > problem (we had an earlier issue with a regression in > 2.6.24) but it looks like the problem is actually with the > tg3 driver.? Our system uses Broadcom ethernet chips. I > tried the same experiments with combination of boards that > have Broadcom and none-Broadcom and the only time I see it > fail is with the tg3? driver loaded. > >=20 > > Snooping with WireShark shows that a ARP request from > the non-Broadcom machine is seen and even answered, but > never appears back on the network. If the Broadcom machine > orginates the ARP message, it never arrives at the > destination. I tried lowering the size of the MTU to 1492 as > well as giving each VLAN device a different MAC. No deal. > >=20 > > I tried to look at tg3 patch changes from 2.6.26 to > 2.6.27 but I am not familiar enough with the Git system to > extract the appropiate changes.? I am a bit surprised that I > am not seeing any references to this on the web, the > combination of >2.6.27 kernels, Broadcom and VLAN cant be > that uncommon. > >=20 > > I would be happy to provide more information and to > try tests if any one can suggest them. > >=20 > > Sincerely, > >=20 > > Gertjan >=20 > I don't see any reason why your setup should fail, but it > doesn't hurt > to gather more info about the problem. >=20 > What device are you experiencing this problem with?=A0 > Is management > firmware enabled?=A0 (`ethtool -i ethx`) >=20 > =20