Return-path: Received: from mfe1.polimi.it ([131.175.12.23]:47589 "EHLO polimi.it" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750982AbXKPOw3 (ORCPT ); Fri, 16 Nov 2007 09:52:29 -0500 Date: Fri, 16 Nov 2007 15:49:02 +0100 From: Stefano Brivio To: Kalle Valo Cc: Johannes Berg , Li YanBo , Ben Gamari , linux-wireless@vger.kernel.org, Jose Ignacio Naranjo Hernandez , Michael Wu , Jouni Malinen Subject: Re: Suspend/Resume support Message-ID: <20071116154902.16b7866c@morte> (sfid-20071116_145231_953493_447BD3C9) In-Reply-To: <87ir42z5kq.fsf@nokia.com> References: <1195087905.3814.11.camel@mercury> <1197ff4c0711141937gc7bb1f8w499cd9d8634fa232@mail.gmail.com> <1195171869.8147.79.camel@johannes.berg> <87ir42z5kq.fsf@nokia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-wireless-owner@vger.kernel.org List-ID: On Fri, 16 Nov 2007 15:24:21 +0200 Kalle Valo wrote: > Johannes Berg writes: > > > If it is, we need to determine whether we were suspended long enough > > for it to kick us off. It might be possible to do this by sending a > > null function frame to the AP and see if it replies with a deauth > > notification, I think it should if we're not associated [3]. > > I think that at least most (if not all) of the APs do send a deauth > frame in that case. I have seen this happening when debugging some > bugs. But I don't know if the standard specifies that. Yes, it does - implicitly. Please see 802.11, 7.3.1.7, Table 18, reason codes of deauthentication frames are 6 for "Class 2 [1] frame received from nonauthenticated station" and 7 for "Class 3 [1] frame received from nonassociated station". But IIRC hostapd doesn't do that, some APs in my neighborhood and mine don't either - I'd say this isn't strongly required by the standard. I'd suggest that, in case we don't get a reply for some time, we should retry association. The problem here is that some userspace tools like wpa_supplicant retry association by themselves, and there could be issues with roaming. On the other side, if we don't want to break wireless extensions compatibility, we should ensure that, once we set an ESSID with - say - iwconfig, we stay associated and - in case - reassociate. [1] 802.11, 5.5 -- Ciao Stefano