Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756506AbaKSTvr (ORCPT ); Wed, 19 Nov 2014 14:51:47 -0500 Received: from na3sys009aog112.obsmtp.com ([74.125.149.207]:35445 "HELO na3sys009aog112.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1756385AbaKSTvo (ORCPT ); Wed, 19 Nov 2014 14:51:44 -0500 From: Joe Stringer To: Pravin Shelar Subject: Re: [ovs-dev] [PATCH net] openvswitch: Fix mask generation for IPv6 labels. Date: Wed, 19 Nov 2014 11:51:39 -0800 User-Agent: KMail/1.13.7 (Linux/3.2.0-4-amd64; KDE/4.8.4; x86_64; ; ) Cc: "dev@openvswitch.org" , netdev , LKML References: <1416336857-61405-1-git-send-email-joestringer@nicira.com> <201411190948.11857.joestringer@nicira.com> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201411191151.40064.joestringer@nicira.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday, November 19, 2014 11:08:35 Pravin Shelar wrote: > On Wed, Nov 19, 2014 at 9:48 AM, Joe Stringer wrote: > > On Wednesday, November 19, 2014 00:11:01 Pravin Shelar wrote: > >> On Tue, Nov 18, 2014 at 11:25 PM, Joe Stringer > > > > wrote: > >> > On 18 November 2014 22:09, Pravin Shelar wrote: > >> >> On Tue, Nov 18, 2014 at 10:54 AM, Joe Stringer > >> >> > >> >> > >> >> wrote: > >> >> > When userspace doesn't provide a mask, OVS datapath generates a > >> >> > fully unwildcarded mask for the flow. This is done by taking a > >> >> > copy of the flow key, then iterating across its attributes, > >> >> > setting all values to 0xff. This works for most attributes, as the > >> >> > length of the netlink attribute typically matches the length of > >> >> > the value. However, IPv6 labels only use the lower 20 bits of the > >> >> > field. This patch makes a special case to handle this. > >> >> > > >> >> > This fixes the following error seen when installing IPv6 flows > >> >> > without a mask: > >> >> > > >> >> > openvswitch: netlink: Invalid IPv6 flow label value > >> >> > (value=ffffffff, max=fffff) > >> >> > >> >> We should allow exact match mask here rather than generating > >> >> wildcarded mask. So that ovs can catch invalid ipv6.label. > >> > > >> > I don't quite follow, I thought this was exact-match? (The existing > >> > function sets all bits to 1) > >> > >> With 0xffffffff value we can exact match on all ipv6.lable bits. > > > > The label field is only 20 bits. The other bits in the same word of the > > IPv6 header are for version (fixed) and traffic class (handled > > separately). We don't do anything with the other bits. > > This is just to make sure that we do not use those field for any thing > else. Masking those extra bits can hide incorrect ipv6 key extraction. Oh, I see. I meant something more like: ipv6_key->ipv6_label &= htonl(0xFFF00000); ipv6_key->ipv6_label |= htonl(0x000FFFFF); (Which would propagate the invalid bits from the flow key, but actually produce an exact match). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/