From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: VLAN and ARP failure on tg3 drivers Date: Fri, 23 Oct 2009 07:23:07 +0200 Message-ID: <4AE13DBB.9010101@gmail.com> References: <93821.71108.qm@web32607.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 To: Gertjan Hofman Return-path: Received: from gw1.cosmosbay.com ([212.99.114.194]:47439 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750799AbZJWFXF (ORCPT ); Fri, 23 Oct 2009 01:23:05 -0400 In-Reply-To: <93821.71108.qm@web32607.mail.mud.yahoo.com> Sender: netdev-owner@vger.kernel.org List-ID: Gertjan Hofman a =E9crit : > 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 pr= oblem 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 kernel= s with Ubuntu .config files. Kernels up to 2.6.26 work fine, kernels a= fter and including 2.6.27 fail. The problem is that ARP messages are be= ing dropped. If the ARP table is updated by hand on each machine, the c= ommunication across the VLAN works fine. >=20 > At first I thought the kernel VLAN code was the problem (we had an ea= rlier 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 chi= ps. I tried the same experiments with combination of boards that have B= roadcom and none-Broadcom and the only time I see it fail is with the t= g3 driver loaded. >=20 > Snooping with WireShark shows that a ARP request from the non-Broadco= m machine is seen and even answered, but never appears back on the netw= ork. If the Broadcom machine orginates the ARP message, it never arrive= s at the destination. I tried lowering the size of the MTU to 1492 as w= ell 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 n= ot familiar enough with the Git system to extract the appropiate change= s. 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 Hello Gertjan I'll take a look at this problem and try to reproduce it, but I use VLA= N + tg3 + bonding without noticing a regression yet. Only difference is I use "ip link add link" command to setup VLANS, not= vconfig, a bit deprecated. Could you try something like this setup=20 ip link set eth1 up ip link add link eth1 vlan.103 type vlan id 103 ip addr add 192.168.20.110/24 dev vlan.103 ip link set vlan.103 up