From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: [PATCH 2/2] ipv4: flush ARP entries on device change Date: Wed, 03 Mar 2010 15:44:49 +0100 Message-ID: <4B8E75E1.8060909@trash.net> References: <1267624874-22326-1-git-send-email-timo.teras@iki.fi> <1267624874-22326-2-git-send-email-timo.teras@iki.fi> <4B8E6CC8.3080701@trash.net> <4B8E701D.7070300@iki.fi> <4B8E7357.5050203@trash.net> <4B8E74A8.5060600@iki.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: =?ISO-8859-15?Q?Timo_Ter=E4s?= Return-path: Received: from stinky.trash.net ([213.144.137.162]:41418 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754713Ab0CCOou (ORCPT ); Wed, 3 Mar 2010 09:44:50 -0500 In-Reply-To: <4B8E74A8.5060600@iki.fi> Sender: netdev-owner@vger.kernel.org List-ID: Timo Ter=E4s wrote: > Patrick McHardy wrote: >> Timo Ter=E4s wrote: >>> Patrick McHardy wrote: >>>> Timo Teras wrote: >>>> It would be nice if we could restrict this to IFF_NOARP changes. >>> Yes. But I did not see any easy way to figure out which flags have >>> changed. >>> >>> Should we just keep a copy of the previous IFF_NOARP bit somewhere >>> (where?). >>> Or did I miss something obvious? >> >> We shouldn't have any arp entries for devices with IFF_NOARP set, >> so perhaps we can flush only in that case. The transition IFF_NOARP >> -> ~IFF_NOARP shouldn't need flushing. >=20 > IFF_NOARP devices do have neighbor entries with the nud NOARP. > Exactly those entries I want to flush when IFF_NOARP flag is > removed. >=20 > You can see those entries with "ip neigh show nud all". You have > them e.g. for loopback stuff and broad-/multicast stuff in general. > With IFF_NOARP you get them on all unicast addresses used. I see. I don't have a better suggestion, except perhaps to store the bit in dev->priv_flags.