From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-15?Q?Timo_Ter=E4s?= Subject: Re: [PATCH 2/2] ipv4: flush ARP entries on device change Date: Wed, 03 Mar 2010 16:39:36 +0200 Message-ID: <4B8E74A8.5060600@iki.fi> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: Patrick McHardy Return-path: Received: from mail-ww0-f46.google.com ([74.125.82.46]:63446 "EHLO mail-ww0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754371Ab0CCOjj (ORCPT ); Wed, 3 Mar 2010 09:39:39 -0500 Received: by wwa36 with SMTP id 36so798894wwa.19 for ; Wed, 03 Mar 2010 06:39:37 -0800 (PST) In-Reply-To: <4B8E7357.5050203@trash.net> Sender: netdev-owner@vger.kernel.org List-ID: 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 c= hanged. >> >> Should we just keep a copy of the previous IFF_NOARP bit somewhere >> (where?). >> Or did I miss something obvious? >=20 > 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. IFF_NOARP devices do have neighbor entries with the nud NOARP. Exactly those entries I want to flush when IFF_NOARP flag is removed. 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. - Timo