Re: current btle 6lowpan issues

[Jukka Rissanen <jukka.rissanen@linux.intel.com>]

Hi Alex,

On Wed, 2016-06-15 at 20:02 +0200, Alexander Aring wrote:
> Hi,
> 
> I like to collect some _big_ issues which I detected on current btle
> 6lowpan
> implementation, these are:
> 
>  1. The l2 daddr comes not from ndisc cache. This should come from
> ndisc
>     cache, instead the implementation construct the l2 from L3
> address
>     which only works for autoconfiguration addresses, all other
>     addresses seems not be working for btle 6lowpan.
> 
>  2. The dev->dev_addr should be the 6 byte baddr and NOT the eui64
>     generated baddr with fffe pattern and u/l bit. The eui64 should
> not
>     be part of source/target address options of ndisc messages, it
> should
>     be the baddr in big endian format. (dev->addr_len need to be 6
> then,
>     as well). baddr is the mac address of btle transceiver.
> 
> The 1. is easy to fix, but then I detected if we do that, the
> neighbour
> cache messages NS/NA/RS, etc use the eui64 fffe pattern with u/l bit
> for
> these messages, because the issue 2. So we will get the wrong address
> from ndisc. The ndisc should store the 6 bytes baddr in big endian
> format.
> So these two issues need to be fixed in some patch and changes
> everything
> in btle 6lowpan.
> 
> I started to work on this but the issue 2. is a big change in btle
> 6lowpan
> so I want to start the discussion about to fix that to doing it in
> the
> right way.
> 
> Jukka, do you agree that this behaviour is currently broken in btle
> 6lowpan?

Yes you are right that there are issues. Fortunately the bt0 is
currently a point-to-point link in which case ND is not really done and
everything kind of "works" ok.

I added Patrik to cc: as he has been working to fix the issues but the
patches are not yet ready. Perhaps we could combine the efforts here.


Cheers,
Jukka