IPv6 broken on Fedora 20?

Jason Berry jbeezo at gmail.com
Thu Dec 19 19:16:44 CET 2013


Similar NM wonkiness going on in Ubuntu.
https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1176415

Regards,
Jason


On Thu, Dec 19, 2013 at 10:14 AM, Hannes Frederic Sowa <
hannes at stressinduktion.org> wrote:

> On Thu, Dec 19, 2013 at 06:59:56PM +0100, Tore Anderson wrote:
> > * Hannes Frederic Sowa
> >
> > > The kernel should install the IPv6 address with /64 prefixlen without
> also
> > > installing a prefix route for that subnet. Currently the kernel does
> this
> > > automatically.
> >
> > I don't think you can do that from user-space. If you add a /64 (any >
> > /128 really), you automatically get a on-link route too. At least I
> > cannot spot how to do it in ip-address(8). So the only way to deal with
> > the L=0 case when doing RA-processing in user-space is to add the
> > address as a /128.
>
> Since the current kernel has extended ifa_flags to 32 bit it is now very
> straightforward and easy to add such functionality (this was done for
> NM correctly supporting privacy addresses). I already had this on my
> todo list for some time but did not get to it.
>
> I still have to review how address and prefix route deletion should happen
> if
> this feature gets introduced.
>
> > Once you're doing that, it's probably easier to handle L=1 by simply
> > adding the on-link route directly, rather than adding the address as a
> > /64 and relying on the kernel to add the route for you. The two should
> > result in the same functionality, though, so I'm don't really understand
> > what's actually broken here.
>
> I guess it breaks generation of privacy addresses.
>
> But you are right, essentially it should work but some assumptions were
> made in the kernel which should have been checked first.
>
> Greetings,
>
>   Hannes
>
>
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