Return-path: Received: from cpsmtpb-ews02.kpnxchange.com ([213.75.39.5]:4599 "EHLO cpsmtpb-ews02.kpnxchange.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758792Ab2EJOrO (ORCPT ); Thu, 10 May 2012 10:47:14 -0400 Message-ID: <4FABD4EB.4070003@gmail.com> (sfid-20120510_164719_962500_86299305) Date: Thu, 10 May 2012 16:47:07 +0200 From: Gertjan van Wingerde MIME-Version: 1.0 To: Andreas Hartmann CC: Ivo Van Doorn , "linux-wireless@vger.kernel.org" , "users@rt2x00.serialmonkey.com" Subject: Re: [rt2x00-users] [PATCH][RFC/RFT] rt2800: Implement selectable support for 802.11w (MFP) References: <201205100719.q4A7JwVl003140@mail.maya.org> <4FAB9EAE.9090403@01019freenet.de> <4FABCECC.30709@01019freenet.de> In-Reply-To: <4FABCECC.30709@01019freenet.de> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 05/10/12 16:21, Andreas Hartmann wrote: > Hi Ivo, > > Ivo Van Doorn wrote: >> Hi, >> >> On Thu, May 10, 2012 at 12:55 PM, Andreas Hartmann >> wrote: >>> Hello! >>> >>> Ivo Van Doorn schrieb: >>>> Hi, >>>> >>>> On Thu, May 10, 2012 at 9:19 AM, Andreas Hartmann >>>> 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 >>>>> --- >>>>> 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. >> >> I am wondering what the usecase would be for having an option to disable MFP? >> Isn't that a feature which technically should be enabled by default and in the >> userspace you have the configuration to use it or not? > > It's the same idea as behind the nohwcrypt switch. If there are problems > with the feature in a special case, you have the possibility to disable it. > My understanding of nohwcrypt is to have a fallback mode, which I didn't > want to touch. That's all. > The difference here is that nohwcrypt has no userspace choice to use it, MFP does have that. Therefore I do not believe there is a need to also be able to enable/disable it at the module level. --- Gertjan