Return-path: Received: from xc.sipsolutions.net ([83.246.72.84]:34663 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753524AbZHTJWl (ORCPT ); Thu, 20 Aug 2009 05:22:41 -0400 Subject: Re: Linux Kernel Wireless stack presentation From: Johannes Berg To: Rami Rosen Cc: linux-wireless@vger.kernel.org In-Reply-To: References: Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-UxlsWfhTKA5pxtvwfd//" Date: Thu, 20 Aug 2009 11:22:10 +0200 Message-Id: <1250760130.4100.23.camel@johannes.local> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: --=-UxlsWfhTKA5pxtvwfd// Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Thu, 2009-08-20 at 10:02 +0300, Rami Rosen wrote: > http://tuxology.net/wp-content/uploads/2009/08/wirelessLecHerzelinux.pdf had a quick look * almost all drivers support passive scanning -- all the modern ones at least -- maybe some old drivers don't, but all using cfg80211 do * your presentation is based on old code -- all the code stuff about scanning is already outdated in wireless-testing * you can scan for multiple specific SSIDs and channels: iw wlan0 scan freq 2412 ssid foo bar baz * iw has a better IE parser, so showing a result from that may be more instructive * code stuff about authentication/association is also outdated already * the STA_MLME_DISABLED stuff no longer exists * AP MLME will never be in the kernel, not just not in the near future :) * raw packets still go through the mac80211 stack, they arrive in monitor_start_xmit() or so * four-address format is not necessarily used only for WDS, the standard doesn't define uses for it (ToDS =3D FromDS =3D 1) * an AP may transmit nullfunc (!) frames to tell clients it has no data buffered, but it never transmits frames with the PM bit on * power timeout 5 is described incorrectly -- it doesn't go to sleep for 5 seconds, it actually stays awake for 5 seconds after each packet transmission -- the time spent asleep is calculated based on the DTIM period etc. Cf. 04fe20372e70685d9f15966216cdffd3795fe590. * STA may wake up in response to TIM[AID] =3D=3D 1 instead of sending PS-poll, which we do depends on the timeout (iwconfig wlan0 power timeout 0 =3D=3D PS-poll, iwconfig wlan0 power timeout 100ms =3D=3D send nullfunc and stay awake for 100ms) * "paramter" typo * ibss is in net/mac80211/ibss.c and has been for quite a while * PM in IBSS is not implemented typically * s/80211.s/802.11s/ * s/80211.n/802.11n/ * you can change the channel with iw (iw phy set freq ...) but it isn't really useful unless you're AP/monitor (and rejected otherwise) * Fedora no longer updates from wireless-testing afaik * wmaster0 is no longer created * assigning interface_modes doesn't set the mode, it just sets the possible modes :) * you can also call iterate_interfaces_atomic() in irq context * nobody cares about the wireless extensions version any more :) * for sniffing you may care about "iw dev set monitor *" Hey that got long! johannes --=-UxlsWfhTKA5pxtvwfd// Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- iQIcBAABAgAGBQJKjRW+AAoJEODzc/N7+QmaM4oP+wTivpH2W76vmBI8v70CPeF3 81ziKxZ8xJOeyKcBN41FN2IQDATFIBj6Lw236MVJFrOKgMJ8FLFB0g5bO9TZWQ6D luC1v7siBCJc8CIfmf0jXzKnoo5F9RtQegEClxdC9crPX9W9jePD3p1u++GXo6xl +XrjZK+EWzrXQ+isAVG66Uec5j7yJyLZnMyvA9Y4BmLbEWxbRCAM9MHWyGjrQBVj ACRGzk6hLPQ9FQhrNICwE+5XZuv6NTFgkj5CZrJ5RRoHns6cojUAPQRcxjvz0rON Onnx/BzP0RGx/jqTtB4tEbBjs0YzCZsXL2lE9u0PQv9c4n+0DfsXyZbj1pDkK2Gr Mwf2SUrG9+czcDeejJFTujW/FTx6kRC0+yjFo50YRnQpgNOC5XtgCl3N3mz7Rw/r 3goo8//Z+sJOjO2kKooadsrCGrJxtMrDahEMpp4XMAIxw+kz6O3UDhO4Erbq4W5T 9jVQ+tp0hble2IAx6FC1GIjIsVrlHwzG5s/zNJ+kuE/ZVh1rdEAKg+TmuiCR2X/M WnJFwwKIPV2kqCKUsItrrei7RKrz10yxHYkHj3tJPD7jfLr3iOZJc6XF9/P9mxjJ sJJWVjIhmxs49ND37WBBHqoX4cO4dYAcj0V5TfYgssUd7T/2H2SaLUBJCXhUYACW vg4RMhZsooaptuW+K7zy =X6N8 -----END PGP SIGNATURE----- --=-UxlsWfhTKA5pxtvwfd//--