From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: Re: [PATCH] filter: introduce SKF_AD_VLAN_PROTO BPF extension Date: Thu, 5 Mar 2015 07:50:53 +0100 Message-ID: <20150305065053.GA2062@nanopsycho.orion> References: <1425501718-12066-1-git-send-email-msekleta@redhat.com> <54F77336.7040006@plumgrid.com> <6E5AAA23-4000-4C29-BB4E-AA7C05B6F619@alum.mit.edu> <54F7997A.3020604@plumgrid.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Guy Harris , Michal Sekletar , netdev@vger.kernel.org To: Alexei Starovoitov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:49712 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754087AbbCEGvD (ORCPT ); Thu, 5 Mar 2015 01:51:03 -0500 Content-Disposition: inline In-Reply-To: <54F7997A.3020604@plumgrid.com> Sender: netdev-owner@vger.kernel.org List-ID: Thu, Mar 05, 2015 at 12:47:06AM CET, ast@plumgrid.com wrote: >On 3/4/15 1:14 PM, Guy Harris wrote: >> >>On Mar 4, 2015, at 1:03 PM, Alexei Starovoitov wrote: >> >>>the patch is correct and looks clean, but I don't understand >>>the motivation for the patch. >>>There is already SKF_AD_VLAN_TAG_PRESENT. If it is set then only >>>two possible values of vlan_proto are ETH_P_8021Q or ETH_P_8021AD. >>>If there another vlan header inside the packet, it's AD. >>>So you can do the filtering already without adding new bpf extension... >> >>I presume he's referring to >> >> https://github.com/the-tcpdump-group/libpcap/issues/397 >> >>or >> >> https://github.com/the-tcpdump-group/libpcap/issues/390 > >ok. context is clear. >yet, it still sounds like something to fix inside libpcap. Libpcap need to somehow let kernel now what vlan proto it should filter on. Also, it is not true that another vlan header inside packet is AD. You can have packet with just AD header (or 2 AD or 2 Q, etc).