Re: [RFC PATCH] xfrm: fix handling of XFRM policies mark and mask.

Romain KUNTZ
2013-02-11T12:58:04Z

Hi Steffen,

Do you plan to resubmit a patch to the mailing list or shall we take care of that?

Thank you,
Romain

On Feb 8, 2013, at 15:16 , Emmanuel Thierry <emmanuel.thierry@telecom-bretagne.eu> wrote:

> Hello,
>
> Le 7 févr. 2013 à 13:54, Steffen Klassert <steffen.klassert@secunet.com> a écrit :
>
>> On Thu, Feb 07, 2013 at 12:08:22PM +0100, Emmanuel Thierry wrote:
>>>
>>> This is a nice idea, however you keep the insertion asymmetric. The usage of xfrm marks in non-conflicting cases will be made possible, but it stays disturbing for a user as the initial example will still have the same behavior:
>>> * Inserting the marked one then the unmarked will succeed
>>> * Inserting the unmarked then the marked one will fail
>>> This gives to the user the feeling of an indeterministic behavior of the xfrm module.
>>
>> This was intended. Inserting the marked one then the unmarked
>> is a working scenario. Some users might rely on it, so we can't
>> change this as you proposed.
>>
>> On the other hand, inserting the unmarked one then the marked
>> might result in a wrong policy lookup, so we can't allow this.
>> The only possibility we have, is inserting with different
>> priorites and that's what I'm proposing.
>>
>> I fear we have to live with that asymmetric behaviour if
>> both policies have the same priority.
>>
>
> Ok, actually i understand the concern of backward compatibility you expose. It is true that users might be disturbed if we change such a behavior they would rely on.
> Anyway, i'm ok with your patch.
>
> Best regards
> Emmanuel Thierry

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