Return-path: Received: from xc.sipsolutions.net ([83.246.72.84]:34301 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751594AbZIWHBa (ORCPT ); Wed, 23 Sep 2009 03:01:30 -0400 Subject: Re: Comparison of wpa_supplicant with -Dnl80211 and -Dwext, WEP and WPA From: Johannes Berg To: Holger Schurig Cc: hostap@lists.shmoo.com, linux-wireless@vger.kernel.org In-Reply-To: <200909221258.44921.hs4233@mail.mn-solutions.de> References: <200909221118.04569.hs4233@mail.mn-solutions.de> <200909221258.44921.hs4233@mail.mn-solutions.de> Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-7VSuPHq/N8pKQW4Zx3dI" Date: Wed, 23 Sep 2009 09:01:31 +0200 Message-Id: <1253689291.4458.25.camel@johannes.local> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: --=-7VSuPHq/N8pKQW4Zx3dI Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2009-09-22 at 12:58 +0200, Holger Schurig wrote: > > 0.00000 0.00000: Initializing interface ... > > 0.08801 0.08801: Setting scan request: 0 sec 100000 usec > > 0.25167 0.16365: ioctl[SIOCGIWSCAN]: Resource temporarily unavailable >=20 > This is because wpa_supplicant very early - in > wpa_driver_wext_finish_drv_init() - calls > wpa_driver_wext_disconnect(). This in turn sets a random 32 > character long ESSID, as a desparate means to disconnect. >=20 > Now that an essid is set, the calling chain in the kernel >=20 > cfg80211_netdev_notifier_call(), case NETDEV_UP > cfg80211_mgd_wext_connect() > __cfg80211_connect() > cfg80211_conn_scan( >=20 > get's executed. This starts a scan. >=20 > Later, when wpa_supplicant tries to get a scan result, it will > only get an -EBUSY because of net/wireless/scan.c, function > cfg80211_wext_siwscan(): >=20 > if (rdev->scan_req) { > err =3D -EBUSY; > goto out; > } >=20 >=20 >=20 > However, I'm wondering: if several scan commands are > supposed to add up into the BSS list anyway (and each BSS list > entry by default pruned after 15 seconds), why is it an error > to access the current state of the BSS list while a scan is > in progress? Because the scan request contains info on how to do the scan. johannes --=-7VSuPHq/N8pKQW4Zx3dI Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- iQIcBAABAgAGBQJKucfHAAoJEODzc/N7+QmalXEQAI+9pvN7US0YemTX04JhCbYr FwkYCR0cv+ijQvGk5HRW7XWEwgBpK4LQ/y9dpyDc5fONC8FyJjmyChO5g1ybqRZ3 GDDe0DyU79D2Ttpq53uU4gmXlYJp4AEeE6+9zmTZsTZgVSoDi7iEo2hUIGx7CKTE D5WuNmjoiUaaLC3AyFXIbvVm9at/BpV8BIUI2cRlrNfYRnocDVDHmW8ABRfv6cDY n7OwuuNdrKg7betjeGBy9bpziN9uV3Phs3mgyghD8gWtwBQ4ZG+B5r1dK6PviKED XLvoeOjR/xmtCm0NLfK/k/Iim4pNx/vyAzvLVhoyC2g589cTXWPjzf4XezoK65Lc kM2d9x5kqN1byxhZtRjj0vvPUkU6pAv4ajiny4d0DlrehdRNVwFUM8+yeUTioft7 SszJksPgFicMDgoTG8xU5D+qz8NyPlzXCwjxj/oSvCe9UBHyK+KvxAf1fFZVOWrU gcKVyvvD0VnvAyI6XOaDsA9fV/q9hbGuLaMWk0RQmWPU0j6LVi0CZ3W5l4u8dV4+ G5BzfBz2WfFb3zezl1RuIqDgbo91fSoTxhVeIs4XaPVN048eIZmJ0pDHESv6Tdcm VbAeV+yTVOnK7TFZX2Nu6+dUZdPiaYxjonlURbThRdO0EESHR4V+l6PLzw+W+yWB 8uwvz7FL9VWo57UMv6D2 =2+nI -----END PGP SIGNATURE----- --=-7VSuPHq/N8pKQW4Zx3dI--