netdev - Re: [RFC] ipv6: use a random ifid for headerless devices

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Message-ID: <87r3j74mnh.fsf@nemi.mork.no>
Date:	Mon, 30 Nov 2015 14:55:30 +0100
From:	Bjørn Mork <bjorn@...k.no>
To:	吉藤英明 <hideaki.yoshifuji@...aclelinux.com>
Cc:	network dev <netdev@...r.kernel.org>
Subject: Re: [RFC] ipv6: use a random ifid for headerless devices

吉藤英明 <hideaki.yoshifuji@...aclelinux.com> writes:

>>> +static int addrconf_ifid_random(u8 *eui, struct net_device *dev)
>> +{
>> +       get_random_bytes(eui, 8);
>> +       eui[0] |= 0x02;
>> +       return 0;
>> +}
>> +
>
> Since random identifier is locally assigned, drop the global bit
> instead if setting it.

Yes, definitely. Thanks.  I'm considering reusing __ipv6_regen_rndid()
which already does this correctly, and also avoids some locally assigned
addresses with special meanings.

Another issue with the initial RFC is that every prefix will have a new
random ifid, which isn't necessarily what the users expect.  I wonder if
it would be acceptable to abuse the rndid field for storing a "permanent"
random ifid?

Bjørn

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