Return-path: Received: from ug-out-1314.google.com ([66.249.92.173]:57781 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759217AbXKZQuo (ORCPT ); Mon, 26 Nov 2007 11:50:44 -0500 Received: by ug-out-1314.google.com with SMTP id z38so965060ugc for ; Mon, 26 Nov 2007 08:50:42 -0800 (PST) Message-ID: <474AF95E.1070608@gmail.com> (sfid-20071126_165114_712766_2DC09D23) Date: Mon, 26 Nov 2007 17:50:38 +0100 From: drago01 MIME-Version: 1.0 To: Johannes Berg CC: Dan Williams , linux-wireless , Jouni Malinen , ipw3945-devel , Zhu Yi Subject: Re: mac80211 / iwl3945 + dynamic wep (again) References: <47494851.4070504@gmail.com> (sfid-20071125_100303_057404_A213DFC8) <1195987773.4149.214.camel@johannes.berg> <474955E1.30603@gmail.com> (sfid-20071125_110054_527140_84EF41E2) <1196079245.4149.255.camel@johannes.berg> <1196093064.4202.46.camel@localhost.localdomain> <1196093663.4149.285.camel@johannes.berg> In-Reply-To: <1196093663.4149.285.camel@johannes.berg> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: Johannes Berg wrote: >> Because in the case of hidden SSIDs, wpa_supplicant pretty much says to >> use ap_scan=2. >> >> There are a few problems here: >> >> 1) Historically, some drivers worked better with ap_scan=1 (madwifi), >> others worked better with ap_scan=2 (many fullmac drivers) >> >> 2) scan_ssid=1 hasn't worked consistently on all drivers because it's >> pretty new and many drivers don't support it yet. This is supposed to >> make the driver/firmware send out probe request for the SSID in >> question. >> >> So basically, we're up shit creek without a paddle. You have to use >> ap_scan=2 on some cards because they don't support specific-ssid >> scanning (with scan_ssid=1) to find the BSS you want to connect to, but >> some cards can handle ap_scan=1+scan_ssid=1 OK. >> > > Fun. I'm pretty sure mac80211 handles ap_scan=1/scan_ssid=1 fine, > sending probe requests for that specific SSID. > > yes it does an work fine that way. but ap_scan=2 = no go. I can get some logs tomorrow for you. If I remeber correctly wpa_supplicant just says "Got X scan results" and never find the ssid asked for. >> NM has logic to cache the BSSIDs of APs you've connected to before, and >> to match those up with an SSID when it sees them in the scan list if the >> AP isn't broadcasting the SSID. Unfortunately, that information isn't >> available to wpa_supplicant because wpa_supplicant doesn't have an >> interface to handle that sort of thing. Therefore, when faced with an a >> request to connect to a hidden network, wpa_supplicant must rely >> _entirely_ on the driver Doing The Right Thing with scan_ssid=1 or >> ap_scan=2, and that almost never works due to inconsistency in driver >> implementation. >> > > Who invented hidden SSIDs anyway? Well, I guess I can actually test this > now that I finally have a second mac80211-based wireless card, although > iwl4965 is special wrt. scanning. I guess the trick will be to make > ap_scan=2 work although ap_scan=1/scan_ssid=1 works much better :( > > well a "fix" would be for nm to try ap_scan=2 when it fails fall back to ap_scan=1 + scan_ssid=1 bt thats nothing more than a hack. > We can fix that in nl80211 by making sure that scan_ssid is implemented > right away and whoever has nl80211 support needs to support that so that > we can rely on it... > yes that should finally fix it ... but until then we need something that works.