Re: IPv6 support

[David Woodhouse <dwmw2 infradead org>]

On Wed, 2008-03-26 at 11:12 -0400, Dan Williams wrote:
> I've namespaced all the property names and such for IPv4 so that we can
> add the required bits for IPv6.  At a minimum, we need an ip6 setting
> (see NetworkManagerConfigurationSpecification [1] at live.gnome.org for
> the ipv4 one).  So we'll need to come up with a list of things people
> want to configure with IPv6 on their boxes:
> 
> David, what sort of stuff would people want to override?  I assume we
> should allow people to override the router (ignoring the advertisement),
> DNS servers (ignoring the RDNSS stuff), and add additional manual IPv6
> addresses?

That's about it for now, I suspect -- until you get to the fun stuff
like doing 6to4 or other tunnels.

One thing to note is that 'dns-search' from your ipv4 settings isn't
really IPv4-specific. That's used for both IPv4 and IPv6. To a certain
extent, the same goes for DNS servers too. You can mix and match IPv4
and IPv6 nameservers in /etc/resolv.conf.

> Next, internally in NM, we'll need an IP6Config structure that contains
> all the information from the ip6 setting object described above, and
> holds other stuff that might be necessary to apply to the system when
> the device is activated (static IPv6 routes, MTU, etc).  Once that's
> done, we'll need to start setting the IPv6 config bits into the device
> activation process, which shouldn't be too hard.
> 
> One interesting question: if you have both IPv6 and IPv4 DHCP config for
> a specific connection/device, what happens if IPv4 DHCP fails, but the
> IPv6 config is fine?  Should the activation fail?  Or should it succeed?
> Something think about, but we can handle that when we get there.

That's probably something the user will want to configure. Many might
want it to fail, but a lot of the time I've been quite happy with IPv6
connectivity and haven't even _noticed_ when IPv4 has failed (like when
NM put the IPv4 default route on the wrong interface last week, etc.)

> There's a few more bits, but this is a start and it should be pretty
> easy to start spec-ing out the setting bits, and adding the generic
> structures into the NM code.
> 
> > If it is a success, another project I'd like to see/work on in nm is
> > automatic 6to4 configuration, you just check the ipv6 box, and if you
> > have an ipv4 public address it just works :)
> > Long term goal would probably be:
> > - 6to4 for public ipv4 addresses
> > - teredo for people behind NAT
> > - optionally connection via a tunnel broker (and connection over dns for
> >   people who don't want to pay in a hostspot ? ;)

That would be cute :)

-- 
dwmw2