Re: [B.A.T.M.A.N.] [PATCH] batman-adv: Use safer default config for optional features

[Sven Eckelmann <sven@narfation.org>]

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On Friday 06 February 2015 14:20:28 Antonio Quartulli wrote:
> To me this looks like the caching effect of DAT: bat0 is likely to
> change MAC address everytime you recreate the interface (unless you
> statically assign the MAC) therefore I presume that the other node (the
> one which did not reboot) was still caching the old bat0 MAC address
> (each entry requires some minutes before being invalidated/refreshed).

Thanks for the explanation.

So you are basically saying that DAT cannot detect when some nodes found a 
conflict in their ARP table (when receiving IP packets with a different MAC 
for an IP or similar things)? And there is also the problem when no local 
information is stored and only a conflict with some data data on another 
unrelated node is happened.

The first conflict (the conflict in the local ARP table) is not detected 
because David wanted that batman-adv isn't accessing the ARP table?

> This means that any communication willing to contact the rebooted node
> was targetting the old address and therefore the two were not be able
> talk until the cache was refreshed.
> 
> Can this be the case?

Yes, unfortunately I hadn't the time to analyze it further and have no logs of 
any similar problem. Thats why I cannot check if this is contradicted by 
anything I've done (or not done). So it is a very plausible scenario which 
you've described.

Maybe Marek can tell me more why he chose to disable it.

Kind regards,
	Sven

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