From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roy Marples Subject: Re: [PATCH] ipv6: do not add link-local address if one already exists Date: Mon, 11 Aug 2014 22:22:04 +0100 Message-ID: <5734a020ebb2bd95d61ba282243719bd@mail.marples.name> References: <1407703032.2161.22.camel@localhost> <1407715900.2161.24.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Hannes Frederic Sowa Return-path: Received: from uberserver.marples.name ([77.75.106.61]:54387 "EHLO mail.marples.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751747AbaHKVWI (ORCPT ); Mon, 11 Aug 2014 17:22:08 -0400 In-Reply-To: <1407715900.2161.24.camel@localhost> Sender: netdev-owner@vger.kernel.org List-ID: Hi On 2014-08-11 01:11, Hannes Frederic Sowa wrote: > On Mo, 2014-08-11 at 00:05 +0000, Roy Marples wrote: >> On 2014-08-10 20:37, Hannes Frederic Sowa wrote: >> > On So, 2014-08-10 at 19:56 +0000, Roy Marples wrote: >> >> Currently the kernel will always add an IPv6 link-local address >> >> based on the hardware address when the interface is brought up. >> >> This is probably based on the assumption that userland would >> >> never add one before the interface is brought up. >> >> >> >> However, one at least one userland application (dhcpcd) does this so >> >> it can implement RFC7217 which can be used for link-local addresses >> >> as well. >> >> >> >> Attached is a patch which checks to see if a link-local address exists >> >> before indiscriminately adding one. >> > >> > Please have a look at: >> > https://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/commit/?id=bc91b0f07ada5535427373a4e2050877bcc12218 >> > >> > This was recently implemented just for this specific case. >> >> Is that tunable available in /proc or /sys? >> I'm not overly keen on adding a netlink call just for that in dhcpcd, >> it >> would be a lot of bloat compared to the kernel patch. > > Can you call iproute via a script? Would that fit your needs? > https://git.kernel.org/cgit/linux/kernel/git/shemminger/iproute2.git/commit/?h=net-next&id=ff7c20844049be836c10087cb2418b99ff36ca2b Not really as there is no guarantee iproute2 is installed on the host. For now, I've added a netlink call at the expense of around 400 bytes. Thanks Roy