Re: alignment problem with ebt_among on ppc

[Bart De Schuymer <bdschuym@pandora.be>]

Op 10/02/2012 13:17, Joerg Willmann schreef:
> On Thu, 9 Feb 2012, Bart De Schuymer wrote:
>
>> Op 3/02/2012 8:21, joe@clnt.de schreef:
>>> What I've seen is that ebt_among extension of ebtables uses
>>> __alignof__(_xt_align) while the corresponding kernel module uses
>>> __alignof__(ebt_replace) to determin the alignment in EBT_ALIGN().
>>>
>>> These are the results of these values on different platforms:
>>>
>>> x86 x86_64 ppc
>>> __alignof__(_xt_align) 4 8 8
>>> __alignof__(ebt_replace) 4 8 4
>>>
>>> So I assume here we can see why ebtales fails to add rules which use 
>>> the
>>> among extension.
>>>
>>> I'm using kernel 2.6.33 and ebtables 2.0.10-4
>>>
>>> Is this a known issue or are there any suggestions how to circumvent 
>>> this
>>> problem?
>>> Thankyou very much.
>>
>> The userspace alignment was changed to _xt_align to fix an alignment 
>> issue on a userspace32-kernel64 system (I think it was for an ARM 
>> device). So userspace must be right. The kernel alignment macro needs 
>> to change so it also uses _xt_align instead of ebt_replace. The 
>> userspace changes date back from June 29, 2009.
>> Can you do these changes and provide a patch?
>>
> Thank you very much for the input. I did the proposed changes which 
> solved my problem.
> See below for the patch (hopefully it's the way you expect it...)
>
> Best regards,
> Joerg
>
> ---
>
>
> diff -rupN a/include/linux/netfilter_bridge/ebtables.h 
> b/include/linux/netfilter_bridge/ebtables.h
> --- a/include/linux/netfilter_bridge/ebtables.h    2010-08-02 
> 19:27:18.000000000 +0200
> +++ b/include/linux/netfilter_bridge/ebtables.h    2012-02-10 
> 12:01:56.464822589 +0100
> @@ -285,8 +285,8 @@ struct ebt_table {
>      struct module *me;
>  };
>
> -#define EBT_ALIGN(s) (((s) + (__alignof__(struct ebt_replace)-1)) & \
> -             ~(__alignof__(struct ebt_replace)-1))
> +#define EBT_ALIGN(s) (((s) + (__alignof__(struct _xt_align)-1)) & \
> +             ~(__alignof__(struct _xt_align)-1))
>  extern struct ebt_table *ebt_register_table(struct net *net,
>                          const struct ebt_table *table);
>  extern void ebt_unregister_table(struct ebt_table *table);
>
>
This patch is fine by me... Please apply.

Signed-off by: Bart De Schuymer <bdschuym@pandora.be>