Subject: Re: [PATCH] ipv6: do not add link-local address if one already exists

From: Hannes Frederic Sowa <[email-masked]>
Date: Mon, 11 Aug 2014 02:11:40 +0200

On Mo, 2014-08-11 at 00:05 +0000, Roy Marples wrote:
> Hi
> 
> 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

Bye,
Hannes