[arch-projects] [netctl] [RFC] Flush the interface configuration in ip_unset instead of bring_interface_down.

[Jouke Witteveen]

On Thu, May 16, 2013 at 11:07 AM, Thomas Bächler <thomas at archlinux.org> wrote:
> Am 16.05.2013 10:59, schrieb Jouke Witteveen:
>> On Thu, May 9, 2013 at 11:53 PM, Thomas Bächler <thomas at archlinux.org> wrote:
>>> Am 09.05.2013 23:29, schrieb Thomas Bächler:
>>>> When switching networks in auto.action, the addresses are not flushed. This
>>>> is especially problematic with stateless ipv6 autoconfigutation, as invalid
>>>> IPs may stay around until their (potentially very long) lifetime has expired.
>>>>
>>>> bring_interface_down is always called after ip_unset everywhere else, so
>>>> this change does not affect anything else.
>>>
>>> This may not be a good idea, since it probably flushes the link-local
>>> address. I must test more.
>>>
>>
>> It does indeed flush the link-local address too.
>> When are link-local addresses added and why is it bad to flush them?
>
> They are added on interface creation (or maybe when bringing the
> interface down/up) by the kernel. Without a link-local address, lots of
> IPv6 functionality simply fails - it is permanently assigned to the
> interface and never changes (you probably can change it, but I don't see
> the point, unless you want to hide your MAC address somehow).

In my testing (with a wireless card), not on down/up. I asked because
I thought maybe its okay to flush them and reinstate them in ip_set,
but apparently that is not the case.

> Best idea is to simply flush addresses in site, global and host scope as
> I stated before. This flushed all ipv6 addresses except link-local, and
> all ipv4 addresses.

Shall I just modify your original patch and make you the author of the commit?

Thanks,
- Jouke