Re: [PATCH] Assign linklocal addresses to isatap from link dev

[David Miller <davem@davemloft.net>]

From: Sascha Hlusiak <mail@saschahlusiak.de>
Date: Wed, 4 Mar 2009 18:49:41 +0100

> > > That way stateless autoconf works with isatap tunnels and without
> > > knowledge of the local v4 address.
> >
> > Real autoconf is not performed, but rather you must configure your
> > system with a PRL (potential routers list) and these routers are
> > probed periodically in order to keep track of which of them are still
> > functioning and also to perform a sort-of unicast-only autoconf.
> Well, since ISATAP is just a SIT, it still needs a link local address for 
> autoconf and it needs to have it's v4 Address embedded in the lowest 32 bit of 
> the linklocal address. It will then do normal autoconf with the potential 
> router by sending a proper router solicitation messages, either directed or 
> multicast.
> 
> I see that the current implementation disables sending of RS when on ISATAP, 
> which is not correct because RS are needed to do the autoconf.
> 
> At least that's the way the implementation in MS Windows works.
> 
> > I am pretty sure that the person who added the ISATAP code created the
> > current behavior intentionally.
> Well, the current implementation does not cover clients at all, because 
> the ip command refuses to create tunnels without the remote parameter, which 
> is neccessary because it's the potential router.
> 
> It then does not derive the linklocal address correctly, making it impossible 
> to do autoconf with the server. Using SIT does work as such as you still need 
> to add the correct ISATAP linklocal address to the interface. 
> 
> I think ISATAP Client support in Linux could be more automated.

Let's ask the ISATAP author the intent of the situation.
CC:'d

Fred?