Re: [rt2x00-users] [PATCH][RFC/RFT] rt2800: Implement selectable support for 802.11w (MFP)

[Andreas Hartmann <andihartmann@01019freenet.de>]

Hello!

Ivo Van Doorn schrieb:
> Hi,
> 
> On Thu, May 10, 2012 at 9:19 AM, Andreas Hartmann
> <andihartmann@01019freenet.de> wrote:
>> This patch adds support for 802.11w for rt2800. This is achieved by
>> using the 802.11w implementation in mac80211.
>>
>> To get this working, it is necessary to disable hw encryption of
>> rt2800pci / rt2800usb, because I don't know of any support in hardware
>> for 802.11w and therefore let mac80211 do the whole job.
>>
>> The user can enable 802.11w with the new mod parameter enablemfp.
>> Enabling MFP disables hw encryption.
>>
>> 802.11w is deactivated per default.
>>
>> Tested with rt2860 and rt3572.
>>
>> This is a workaround as long as there isn't hardware support implemented
>> in the driver.
>>
>> Signed-off-by: Andreas Hartmann <andihartmann@01019freenet.de>
>> ---
>> diff -ur compat-wireless-2012-04-26.orig/drivers/net/wireless/rt2x00/rt2800lib.c compat-wireless-2012-04-26/drivers/net/wireless/rt2x00/rt2800lib.c
>> --- compat-wireless-2012-04-26.orig/drivers/net/wireless/rt2x00/rt2800lib.c     2012-04-26 22:10:30.000000000 +0200
>> +++ compat-wireless-2012-04-26/drivers/net/wireless/rt2x00/rt2800lib.c  2012-05-09 11:37:48.463278177 +0200
>> @@ -4519,6 +4519,15 @@
>>            IEEE80211_HW_AMPDU_AGGREGATION |
>>            IEEE80211_HW_REPORTS_TX_ACK_STATUS;
>>
>> +       /*
>> +        * Enable support for 802.11w in mac80211. hwencryption must be disabled
>> +        */
>> +       if (!test_bit(CAPABILITY_HW_CRYPTO, &rt2x00dev->cap_flags) && rt2x00dev->mfprequested) {
>> +               INFO(rt2x00dev, "802.11w support (MFP) enabled.\n");
>> +               rt2x00dev->hw->flags |=
>> +                       IEEE80211_HW_MFP_CAPABLE;
>> +       }
> 
> Can't the whole patch be simplified into
> 
> if (!test_bit(CAPABILITY_HW_CRYPTO, &rt2x00dev->cap_flags)) {
>                INFO(rt2x00dev, "802.11w support (MFP) enabled.\n");
>                rt2x00dev->hw->flags |=
>                        IEEE80211_HW_MFP_CAPABLE;
> }

This would surely be possible, but it wouldn't be possible any more to
run the driver w/o MFP support as long as hw encryption is disabled.

Additionally, I would like to have an additional comment added to
nohwcrypt, which mentions, that activating nohwcrypt enables MFP, like:
"Disable hardware encryption, enable MFP." to let the user know, how to
enable MFP.

> 
> Why need a extra moduleflag when all it does is toggle the nohwcrypto
> module parameter?

Because I wanted to achieve the old behaviour of the driver w/o hw
encryption.
If you think, this isn't necessary, I'm absolutely fine with removing it.


Andreas