Re: IPv6 support

[Dan Williams <dcbw redhat com>]

On Wed, 2008-03-26 at 16:23 +0000, David Woodhouse wrote:
> 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.

Right...  that information can get populated in two ways right now:
through a settings service (and therefore set up by the user either with
ifcfg files or the connection editor/GConf) or via DHCP.  In the DHCP
case, the searches are specific to the IPv4 configuration of the
interface.  In the user-specified case, you're completely correct that
they aren't IPv4 specific.

'dns-search' belongs in the same class as 'hostname', which I hope to
support sometime soon when libICE stops doing gethostbyname() for
ORBit/Bonobo crap and blocking apps for 30 seconds on launch.

Dan

> > 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 :)
>