IPv6 broken on Fedora 20?

[Lorenzo Colitti]

On Fri, Dec 20, 2013 at 1:34 AM, Hannes Frederic Sowa <
hannes at stressinduktion.org> wrote:

> > > NM has a user-space RA listener.
> > >
> >
> > Sigh. Why do we keep reinventing the wheel? What was wrong with the
> > in-kernel RA implementation?
>
> I wondered myself and got this response:
> http://www.spinics.net/lists/netdev/msg255581.html


Hmm. It looks like the answer is:

1. "We want to be able to send RS whenever we feel like it." They could
have used disable_ipv6 for that, or they could have made a write to
accept_ra cause an RS to be sent out. Failing that, an RS is not hard to
generate - it's a multicast packet with no information in it.

2. "The kernel doesn't give us enough information to parse RDNSS and DNSSL
options correctly". Fair enough, though this still could have been fixed in
the kernel.

3. The kernel doesn't give userspace any say in the process. If the sysctls
are on, it does what the RA tells it to, and if they're off, then userspace
doesn't see any of the advertisements. This is a better reason than the
ones above. I was looking into fixing this using multiple routing tables.

Dan's proposal to have the kernel do a part of the address config and
userspace do another part seems brittle though.
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