Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756621AbaKSUdM (ORCPT ); Wed, 19 Nov 2014 15:33:12 -0500 Received: from na3sys009aog116.obsmtp.com ([74.125.149.240]:38999 "HELO na3sys009aog116.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1756026AbaKSUdL (ORCPT ); Wed, 19 Nov 2014 15:33:11 -0500 MIME-Version: 1.0 In-Reply-To: <201411191151.40064.joestringer@nicira.com> References: <1416336857-61405-1-git-send-email-joestringer@nicira.com> <201411190948.11857.joestringer@nicira.com> <201411191151.40064.joestringer@nicira.com> Date: Wed, 19 Nov 2014 12:33:10 -0800 Message-ID: Subject: Re: [ovs-dev] [PATCH net] openvswitch: Fix mask generation for IPv6 labels. From: Pravin Shelar To: Joe Stringer Cc: "dev@openvswitch.org" , netdev , LKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 19, 2014 at 11:51 AM, Joe Stringer wrote: > 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). yes, it can wildcard unused bits. -- 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/