From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krzysztof Halasa Subject: Re: Linux, tcpdump and vlan Date: Thu, 19 Jul 2007 15:28:46 +0200 Message-ID: References: <878246.51044.qm@web56608.mail.re3.yahoo.com> <469E9AC8.3090603@trash.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: andrei radulescu-banu , linux-kernel@vger.kernel.org, Linux Netdev List To: Patrick McHardy Return-path: Received: from khc.piap.pl ([195.187.100.11]:34655 "EHLO khc.piap.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754016AbXGSN2u (ORCPT ); Thu, 19 Jul 2007 09:28:50 -0400 In-Reply-To: <469E9AC8.3090603@trash.net> (Patrick McHardy's message of "Thu, 19 Jul 2007 00:57:12 +0200") Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Patrick McHardy writes: > Your suggestion of disabling VLAN acceleration in promiscous > mode sounds like a reasonable solution until then .. >>From a user perspective: I'm not sure promiscous mode is related to the problem. Tcpdump without promiscous mode makes perfect sense. I don't know very well VLAN code internals, but I think the VLAN # is used for looking up the interface, so presenting the "original" packet on the trunk device would IMHO involve some skb cloning, and perhaps some ethtool option could probably control that. Not sure about untagged frames vs. tagged frames with the default VLAN id - can the hardware at all differentiate between them? Or, perhaps it should be left (almost) as is - with "software" VLANs the traffic always goes through the master interface, but with "accelerated" mode it only goes through logical interfaces and doesn't show up on master? Probably with exception of invalid VLANs, which could be injected back to master (because no logical device exists)? -- Krzysztof Halasa