History log of /freebsd-current/sys/net80211/ieee80211_power.c
Revision Date Author Comments
# 685dc743 16-Aug-2023 Warner Losh <imp@FreeBSD.org>

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/


# 4d846d26 10-May-2023 Warner Losh <imp@FreeBSD.org>

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix


# fb5a5026 09-Apr-2022 Gordon Bergling <gbe@FreeBSD.org>

net80211(4): Fix a typo in a source code comment

- s/is is/is/

MFC after: 3 days


# 662c1305 01-Sep-2020 Mateusz Guzik <mjg@FreeBSD.org>

net: clean up empty lines in .c and .h files


# f1481c8d 30-Jun-2020 Adrian Chadd <adrian@FreeBSD.org>

[net80211] Migrate HT/legacy protection mode and preamble calculation to per-VAP flags

The later firmware devices (including iwn!) support multiple configuration
contexts for a lot of things, leaving it up to the firmware to decide
which channel and vap is active. This allows for things like off-channel
p2p sta/ap operation and other weird things.

However, net80211 is still focused on a "net80211 drives all" when it comes to driving
the NIC, and as part of this history a lot of these options are global and not per-VAP.
This is fine when net80211 drives things and all VAPs share a single channel - these
parameters importantly really reflect the state of the channel! - but it will increasingly
be not fine when we start supporting more weird configurations and more recent NICs.
Yeah, recent like iwn/iwm.

Anyway - so, migrate all of the HT protection, legacy protection and preamble
stuff to be per-VAP. The global flags are still there; they're now calculated
in a deferred taskqueue that mirrors the old behaviour. Firmware based drivers
which have per-VAP configuration of these parameters can now just listen to the
per-VAP options.

What do I mean by per-channel? Well, the above configuration parameters really
are about interoperation with other devices on the same channel. Eg, HT protection
mode will flip to legacy/mixed if it hears ANY BSS that supports non-HT stations or
indicates it has non-HT stations associated. So, these flags really should be
per-channel rather than per-VAP, and then for things like "do i need short preamble
or long preamble?" turn into a "do I need it for this current operating channel".
Then any VAP using it can query the channel that it's on, reflecting the real
required state.

This patch does none of the above paragraph just yet.

I'm also cheating a bit - I'm currently not using separate taskqueues for
the beacon updates and the per-VAP configuration updates. I can always further
split it later if I need to but I didn't think it was SUPER important here.

So:

* Create vap taskqueue entries for ERP/protection, HT protection and short/long
preamble;
* Migrate the HT station count, short/long slot station count, etc - into per-VAP
variables rather than global;
* Fix a bug with my WME work from a while ago which made it per-VAP - do the WME
beacon update /after/ the WME update taskqueue runs, not before;
* Any time the HT protmode configuration changes or the ERP protection mode
config changes - schedule the task, which will call the driver without the
net80211 lock held and all correctly serialised;
* Use the global flags for beacon IEs and VAP flags for probe responses and
other IE situations.

The primary consumer of this is ath10k. iwn could use it when sending RXON,
but we don't support IBSS or AP modes on it yet, and I'm not yet sure whether
it's required in STA mode (ie whether the firmware parses beacons to change
protection mode or whether we need to.)

Tested:

* AR9280, STA/AP
* AR9380, DWDS STA+STA/AP
* ath10k work, STA/AP
* Intel 6235, STA
* Various rtwn / run NICs, DWDS STA and STA configurations


# fe267a55 27-Nov-2017 Pedro F. Giffuni <pfg@FreeBSD.org>

sys: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.


# b8e29e06 29-Mar-2016 Adrian Chadd <adrian@FreeBSD.org>

[net80211] migrate the time_* macros to ieee80211_* namespace.

It turns out that these will clash very annoyingly with the linux
macros in the linuxkpi layer, so let the wookie^Wlinux win.

The only user that I can find is ath(4), so fix it there too.


# 8ec07310 01-Feb-2016 Gleb Smirnoff <glebius@FreeBSD.org>

These files were getting sys/malloc.h and vm/uma.h with header pollution
via sys/mbuf.h


# d3a4ade3 11-Oct-2015 Adrian Chadd <adrian@FreeBSD.org>

net80211: free node reference in the ieee80211_parent_xmitpkt() when error happened.

Move error handling into ieee80211_parent_xmitpkt() instead of spreading it
between functions.

Submitted by: <s3erios@gmail.com>
Differential Revision: https://reviews.freebsd.org/D3772


# 7a79cebf 27-Aug-2015 Gleb Smirnoff <glebius@FreeBSD.org>

Replay r286410. Change KPI of how device drivers that provide wireless
connectivity interact with the net80211 stack.

Historical background: originally wireless devices created an interface,
just like Ethernet devices do. Name of an interface matched the name of
the driver that created. Later, wlan(4) layer was introduced, and the
wlanX interfaces become the actual interface, leaving original ones as
"a parent interface" of wlanX. Kernelwise, the KPI between net80211 layer
and a driver became a mix of methods that pass a pointer to struct ifnet
as identifier and methods that pass pointer to struct ieee80211com. From
user point of view, the parent interface just hangs on in the ifconfig
list, and user can't do anything useful with it.

Now, the struct ifnet goes away. The struct ieee80211com is the only
KPI between a device driver and net80211. Details:

- The struct ieee80211com is embedded into drivers softc.
- Packets are sent via new ic_transmit method, which is very much like
the previous if_transmit.
- Bringing parent up/down is done via new ic_parent method, which notifies
driver about any changes: number of wlan(4) interfaces, number of them
in promisc or allmulti state.
- Device specific ioctls (if any) are received on new ic_ioctl method.
- Packets/errors accounting are done by the stack. In certain cases, when
driver experiences errors and can not attribute them to any specific
interface, driver updates ic_oerrors or ic_ierrors counters.

Details on interface configuration with new world order:
- A sequence of commands needed to bring up wireless DOESN"T change.
- /etc/rc.conf parameters DON'T change.
- List of devices that can be used to create wlan(4) interfaces is
now provided by net.wlan.devices sysctl.

Most drivers in this change were converted by me, except of wpi(4),
that was done by Andriy Voskoboinyk. Big thanks to Kevin Lo for testing
changes to at least 8 drivers. Thanks to pluknet@, Oliver Hartmann,
Olivier Cochard, gjb@, mmoll@, op@ and lev@, who also participated in
testing.

Reviewed by: adrian
Sponsored by: Netflix
Sponsored by: Nginx, Inc.


# ba2c1fbc 07-Aug-2015 Adrian Chadd <adrian@FreeBSD.org>

Revert the wifi ifnet changes until things are more baked and tested.

* 286410
* 286413
* 286416

The initial commit broke a variety of debug and features that aren't
in the GENERIC kernels but are enabled in other platforms.


# 79d2c5e8 07-Aug-2015 Gleb Smirnoff <glebius@FreeBSD.org>

Change KPI of how device drivers that provide wireless connectivity interact
with the net80211 stack.

Historical background: originally wireless devices created an interface,
just like Ethernet devices do. Name of an interface matched the name of
the driver that created. Later, wlan(4) layer was introduced, and the
wlanX interfaces become the actual interface, leaving original ones as
"a parent interface" of wlanX. Kernelwise, the KPI between net80211 layer
and a driver became a mix of methods that pass a pointer to struct ifnet
as identifier and methods that pass pointer to struct ieee80211com. From
user point of view, the parent interface just hangs on in the ifconfig
list, and user can't do anything useful with it.

Now, the struct ifnet goes away. The struct ieee80211com is the only
KPI between a device driver and net80211. Details:

- The struct ieee80211com is embedded into drivers softc.
- Packets are sent via new ic_transmit method, which is very much like
the previous if_transmit.
- Bringing parent up/down is done via new ic_parent method, which notifies
driver about any changes: number of wlan(4) interfaces, number of them
in promisc or allmulti state.
- Device specific ioctls (if any) are received on new ic_ioctl method.
- Packets/errors accounting are done by the stack. In certain cases, when
driver experiences errors and can not attribute them to any specific
interface, driver updates ic_oerrors or ic_ierrors counters.

Details on interface configuration with new world order:
- A sequence of commands needed to bring up wireless DOESN"T change.
- /etc/rc.conf parameters DON'T change.
- List of devices that can be used to create wlan(4) interfaces is
now provided by net.wlan.devices sysctl.

Most drivers in this change were converted by me, except of wpi(4),
that was done by Andriy Voskoboinyk. Big thanks to Kevin Lo for testing
changes to at least 8 drivers. Thanks to Olivier Cochard, gjb@, mmoll@,
op@ and lev@, who also participated in testing. Details here:

https://wiki.freebsd.org/projects/ifnet/net80211

Still, drivers: ndis, wtap, mwl, ipw, bwn, wi, upgt, uath were not
tested. Changes to mwl, ipw, bwn, wi, upgt are trivial and chances
of problems are low. The wtap wasn't compilable even before this change.
But the ndis driver is complex, and it is likely to be broken with this
commit. Help with testing and debugging it is appreciated.

Differential Revision: D2655, D2740
Sponsored by: Nginx, Inc.
Sponsored by: Netflix


# b9b53389 25-May-2015 Adrian Chadd <adrian@FreeBSD.org>

Convert malloc/free back to #define's, as part of OS portability work.

DragonflyBSD uses the FreeBSD wireless stack and drivers. Their malloc()
API is named differently, so they don't have userland/kernel symbol
clashes like we do (think libuinet.)

So, to make it easier for them and to port to other BSDs/other operating
systems, start hiding the malloc specific bits behind defines in
ieee80211_freebsd.h.

DragonflyBSD can now put these portability defines in their local
ieee80211_dragonflybsd.h.

This should be a great big no-op for everyone running wifi.

TODO:

* kill M_WAITOK - some platforms just don't want you to use it
* .. and/or handle it returning NULL rather than waiting forever.
* MALLOC_DEFINE() ?
* Migrate the well-known malloc names (eg M_TEMP) to net80211
namespace defines.


# 1de34f86 20-Dec-2014 Adrian Chadd <adrian@FreeBSD.org>

Update ieee80211_sta_tim_notify() to do double duty - handle STA sleep
to awake transition as well as handle waking up a VAP in STA powersave
mode if it's in bgscan.

This was a reasonably hairy bug to try and figure out and it became
more obvious because of stuff I've done.

Specifically:

* a NIC would go into bgscan mode - either because of a bgscan timer
or wpa_supplicant asked it to;
* the AP would indicate there's traffic for the STA by setting the TIM
bitmap bit for it;
* mindwell would be met during scan, so it'd wake up and break out of
the scan loop in scan_task(), but
* because the scan wasn't completed, it wouldn't bring the VAP out of
STA mode powersave (so it wouldn't tell the AP about it and it would
block VAP TX);
* .. but because we kept seeing the TIM bit set, ic->ic_lastdata was
being constantly updated, and ..
* bgscancont() would thus never say "yes we can continue a bgscan"
so the bgscan would hang and never make progress.

Now, I do see this particular state occur on iwn(4) - /however/ -
this NIC has the firmware call ieee80211_scan_next() once the firmware
scan for that channel has completed. This has the effect of moving
the scan along to the next channel. I do see the debug that I'm adding
where we see a beacon with a TIM bit set whilst we're in bgscan, so
the condition about waking up to receive traffic is triggering.
It just won't cause a hang.

For other NICs - all of the USB ones and at least ath(4) -
ieee80211_scan_next() / ieee80211_scan_done() isn't called.
So it relies upon the mindwell timer, the beacon receive and the
beacon / probe response -> ieee80211_add_scan() to move along
the scan state.

In the above case, mindwell triggered, there's no beacons triggering
the scan_add code to move things along, and we weren't waking things
up when seeing the TIM set for us. So it just hung until the interface
was dropped.

So, the short-term fix here is to do what the comment in scan_task()
says - if we are in bgscan mode and we see our TIM bit set, just wake
up the VAP. If it's already awake then it's a nop. If we're awake
then we transition to awake and handle the traffic. Once there's no
TX or RX traffic going on, ic->ic_lastdata won't be updated anymore
and bgscancont() will continue.

This was triggered more often after my initial SLEEP state handling
for software sleep states - because now I update ic->ic_lastdata
upon seeing a TIM bit set, not just the RX of the subsequent traffic.
That's needed so the thing doesn't ping-pong up and down between
seeing the TIM bit set, sending the "I'm awake" NULL data frame, and
starting to receive data from the AP.

I'd like to subsequently split ic_lastdata into two - one for TX and
one for RX - so it becomes easier to use the correct one (or both!)
when making decisions like whether to scan, go to sleep, etc.

I'd appreciate this getting some further testing.

Tested:

* rsu(4), STA mode, bgscan on
* iwn(4), STA mode, bgscan on


# 902840a5 23-Apr-2014 Adrian Chadd <adrian@FreeBSD.org>

Begin fleshing out support for net80211 provided (legacy) sleep management.

This transitions the VAP in and out of SLEEP state based on:

* whether there's been an active transmission in the last (hardcoded) 500ms;
* whether the TIM from the AP indicates there is data available.

It uses the beacon reception to trigger the active traffic check.
This way there's no further timer running to wake up the CPU
from its own sleep states.

Right now the VAP isn't woken up for multicast traffic - mostly because
the only NIC I plan on doing this for right will auto wakeup and stay
awake for multicast traffic indicated in the TIM. So I don't have
to manually keep the hardware awake.

This doesn't do anything if the NIC doesn't advertise it implements
the new SWSLEEP capability AND if the VAP doesn't have powersave
enabled.

It also doesn't do much with ath(4) as it doesn't currently implement
the SLEEP state.

Tested:

* AR5416, STA mode (with local ath(4) changes)


# 76039bc8 26-Oct-2013 Gleb Smirnoff <glebius@FreeBSD.org>

The r48589 promised to remove implicit inclusion of if_var.h soon. Prepare
to this event, adding if_var.h to files that do need it. Also, include
all includes that now are included due to implicit pollution via if_var.h

Sponsored by: Netflix
Sponsored by: Nginx, Inc.


# 57b5fc5f 12-Aug-2013 Adrian Chadd <adrian@FreeBSD.org>

Blank m_nextpkt before passing it up.


# 4bd57e10 11-Aug-2013 Adrian Chadd <adrian@FreeBSD.org>

When flushing packets from the powersave queue, make sure that
m_nextpkt is NULL before passing it up to the parent transmit
method.


# e7495198 07-Aug-2013 Adrian Chadd <adrian@FreeBSD.org>

Convert net80211 over to using if_transmit for the dispatch from the
upper layer(s).

This eliminates the if_snd queue from net80211. Yay!

This unfortunately has a few side effects:

* It breaks ALTQ to net80211 for now - sorry everyone, but fixing
parallelism and eliminating the if_snd queue is more important
than supporting this broken traffic scheduling model. :-)

* There's no VAP and IC flush methods just yet - I think I'll add
some NULL methods for now just as placeholders.

* It reduces throughput a little because now net80211 will drop packets
rather than buffer them if the driver doesn't do its own buffering.
This will be addressed in the future as I implement per-node software
queues.

Tested:

* ath(4) and iwn(4) in STA operation


# 5cda6006 08-Mar-2013 Adrian Chadd <adrian@FreeBSD.org>

Bring over my initial work from the net80211 TX locking branch.

This patchset implements a new TX lock, covering both the per-VAP (and
thus per-node) TX locking and the serialisation through to the underlying
physical device.

This implements the hard requirement that frames to the underlying physical
device are scheduled to the underlying device in the same order that they
are processed at the VAP layer. This includes adding extra encapsulation
state (such as sequence numbers and CCMP IV numbers.) Any order mismatch
here will result in dropped packets at the receiver.

There are multiple transmit contexts from the upper protocol layers as well
as the "raw" interface via the management and BPF transmit paths.
All of these need to be correctly serialised or bad behaviour will result
under load.

The specifics:

* add a new TX IC lock - it will eventually just be used for serialisation
to the underlying physical device but for now it's used for both the
VAP encapsulation/serialisation and the physical device dispatch.

This lock is specifically non-recursive.

* Methodize the parent transmit, vap transmit and ic_raw_xmit function
pointers; use lock assertions in the parent/vap transmit routines.

* Add a lock assertion in ieee80211_encap() - the TX lock must be held
here to guarantee sensible behaviour.

* Refactor out the packet sending code from ieee80211_start() - now
ieee80211_start() is just a loop over the ifnet queue and it dispatches
each VAP packet send through ieee80211_start_pkt().

Yes, I will likely rename ieee80211_start_pkt() to something that
better reflects its status as a VAP packet transmit path. More on
that later.

* Add locking around the management and BAR TX sending - to ensure that
encapsulation and TX are done hand-in-hand.

* Add locking in the mesh code - again, to ensure that encapsulation
and mesh transmit are done hand-in-hand.

* Add locking around the power save queue and ageq handling, when
dispatching to the parent interface.

* Add locking around the WDS handoff.

* Add a note in the mesh dispatch code that the TX path needs to be
re-thought-out - right now it's doing a direct parent device transmit
rather than going via the vap layer. It may "work", but it's likely
incorrect (as it bypasses any possible per-node power save and
aggregation handling.)

Why not a per-VAP or per-node lock?

Because in order to ensure per-VAP ordering, we'd have to hold the
VAP lock across parent->if_transmit(). There are a few problems
with this:

* There's some state being setup during each driver transmit - specifically,
the encryption encap / CCMP IV setup. That should eventually be dragged
back into the encapsulation phase but for now it lives in the driver TX path.
This should be locked.

* Two drivers (ath, iwn) re-use the node->ni_txseqs array in order to
allocate sequence numbers when doing transmit aggregation. This should
also be locked.

* Drivers may have multiple frames queued already - so when one calls
if_transmit(), it may end up dispatching multiple frames for different
VAPs/nodes, each needing a different lock when handling that particular
end destination.

So to be "correct" locking-wise, we'd end up needing to grab a VAP or
node lock inside the driver TX path when setting up crypto / AMPDU sequence
numbers, and we may already _have_ a TX lock held - mostly for the same
destination vap/node, but sometimes it'll be for others. That could lead
to LORs and thus deadlocks.

So for now, I'm sticking with an IC TX lock. It has the advantage of
papering over the above and it also has the added advantage that I can
assert that it's being held when doing a parent device transmit.
I'll look at splitting the locks out a bit more later on.

General outstanding net80211 TX path issues / TODO:

* Look into separating out the VAP serialisation and the IC handoff.
It's going to be tricky as parent->if_transmit() doesn't give me the
opportunity to split queuing from driver dispatch. See above.

* Work with monthadar to fix up the mesh transmit path so it doesn't go via
the parent interface when retransmitting frames.

* Push the encryption handling back into the driver, if it's at all
architectually sane to do so. I know it's possible - it's what mac80211
in Linux does.

* Make ieee80211_raw_xmit() queue a frame into VAP or parent queue rather
than doing a short-cut direct into the driver. There are QoS issues
here - you do want your management frames to be encapsulated and pushed
onto the stack sooner than the (large, bursty) amount of data frames
that are queued. But there has to be a saner way to do this.

* Fragments are still broken - drivers need to be upgraded to an if_transmit()
implementation and then fragmentation handling needs to be properly fixed.

Tested:

* STA - AR5416, AR9280, Intel 5300 abgn wifi
* Hostap - AR5416, AR9160, AR9280
* Mesh - some testing by monthadar@, more to come.


# 3484d5ad 15-Jan-2013 Adrian Chadd <adrian@FreeBSD.org>

Remove the use of the ifnet send queue and if_start() in the power
save queue code.

Instead, use if_transmit() directly - and handle the cases where frame
transmission fails.

I don't necessarily like this and I think at this point the M_ENCAP check,
node freeing upon fail and the actual if_transmit() call should be done
in methods in ieee80211_freebsd.c, but I digress slightly..

This removes one of the last few uses of if_start() and the ifnet
if_snd queue. The last major offender is ieee80211_output.c, where
ieee80211_start() implements if_start() and uses the ifnet queue
directly.

(There's a couple of gotchas here, where the if_start pointer is
compared to ieee80211_start(), but that's a later problem.)


# e7f0d7cf 02-Oct-2012 Adrian Chadd <adrian@FreeBSD.org>

Migrate the power-save functions to be overridable VAP methods.

This turns ieee80211_node_pwrsave(), ieee80211_sta_pwrsave() and
ieee80211_recv_pspoll() into methods.

The intent is to let drivers override these and tie into the power save
management pathway.

For ath(4), this is the beginning of forcing a node software queue to
stop and start as needed, as well as supporting "leaking" single frames
from the software queue to the hardware.

Right now, ieee80211_recv_pspoll() will attempt to transmit a single frame
to the hardware (whether it be a data frame on the power-save queue or
a NULL data frame) but the driver may have hardware/software queued frames
queued up. This initial work is an attempt at providing the hooks required
to implement correct behaviour.

Allowing ieee80211_node_pwrsave() to be overridden allows the ath(4)
driver to pause and unpause the entire software queue for a given node.
It doesn't make sense to transmit anything whilst the node is asleep.

Please note that there are other corner cases to correctly handle -
specifically, setting the MORE data bit correctly on frames to a station,
as well as keeping the TIM updated. Those particular issues can be
addressed later.


# d745c852 06-Nov-2011 Ed Schouten <ed@FreeBSD.org>

Mark MALLOC_DEFINEs static that have no corresponding MALLOC_DECLAREs.

This means that their use is restricted to a single C file.


# d91933f4 07-Jul-2011 Kevin Lo <kevlo@FreeBSD.org>

Fix memset sizeofs

Reviewed by: bschmidt


# a7d5f7eb 19-Oct-2010 Jamie Gritton <jamie@FreeBSD.org>

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.


# e2126dec 18-Dec-2008 Sam Leffler <sam@FreeBSD.org>

convert MALLOC/FREE to malloc/free


# 63092fce 25-Oct-2008 Sam Leffler <sam@FreeBSD.org>

New ap-side power save implementation; the main change is to allow drivers
to queue frames previously encapsulated on a separate high priority list
that is dispatched before the unencapsulated frames (to preserve order).


# c5abbba3 23-Oct-2008 Dag-Erling Smørgrav <des@FreeBSD.org>

Revert the removal of the MALLOC and FREE macros from the net80211 code.

Requested by: sam


# 1ede983c 23-Oct-2008 Dag-Erling Smørgrav <des@FreeBSD.org>

Retire the MALLOC and FREE macros. They are an abomination unto style(9).

MFC after: 3 months


# d7f03759 19-Oct-2008 Ulf Lilleengen <lulf@FreeBSD.org>

- Import the HEAD csup code which is the basis for the cvsmode work.


# b032f27c 20-Apr-2008 Sam Leffler <sam@FreeBSD.org>

Multi-bss (aka vap) support for 802.11 devices.

Note this includes changes to all drivers and moves some device firmware
loading to use firmware(9) and a separate module (e.g. ral). Also there
no longer are separate wlan_scan* modules; this functionality is now
bundled into the wlan module.

Supported by: Hobnob and Marvell
Reviewed by: many
Obtained from: Atheros (some bits)


# b105a069 17-Sep-2007 Sam Leffler <sam@FreeBSD.org>

Update beacon handling to sync w/ vap code base:
o add driver callback to handle notification of beacon changes;
this is required for devices that manage beacon frames themselves
(devices must override the default handler which does nothing)
o move beacon update-related flags from ieee80211com to the beacon
offsets storage (or handle however a driver wants)
o expand beacon offsets structure with members needed for 11h/dfs
and appie's
o change calling convention for ieee80211_beacon_alloc and
ieee80211_beacon_update
o add overlapping bss support for 11g; requires driver to pass
beacon frames from overlapping bss up to net80211 which is not
presently done by any driver
o move HT beacon contents update to a routine in the HT code area

Reviewed by: avatar, thompsa, sephe
Approved by: re (blanket wireless)


# 68e8e04e 10-Jun-2007 Sam Leffler <sam@FreeBSD.org>

Update 802.11 wireless support:
o major overhaul of the way channels are handled: channels are now
fully enumerated and uniquely identify the operating characteristics;
these changes are visible to user applications which require changes
o make scanning support independent of the state machine to enable
background scanning and roaming
o move scanning support into loadable modules based on the operating
mode to enable different policies and reduce the memory footprint
on systems w/ constrained resources
o add background scanning in station mode (no support for adhoc/ibss
mode yet)
o significantly speedup sta mode scanning with a variety of techniques
o add roaming support when background scanning is supported; for now
we use a simple algorithm to trigger a roam: we threshold the rssi
and tx rate, if either drops too low we try to roam to a new ap
o add tx fragmentation support
o add first cut at 802.11n support: this code works with forthcoming
drivers but is incomplete; it's included now to establish a baseline
for other drivers to be developed and for user applications
o adjust max_linkhdr et. al. to reflect 802.11 requirements; this eliminates
prepending mbufs for traffic generated locally
o add support for Atheros protocol extensions; mainly the fast frames
encapsulation (note this can be used with any card that can tx+rx
large frames correctly)
o add sta support for ap's that beacon both WPA1+2 support
o change all data types from bsd-style to posix-style
o propagate noise floor data from drivers to net80211 and on to user apps
o correct various issues in the sta mode state machine related to handling
authentication and association failures
o enable the addition of sta mode power save support for drivers that need
net80211 support (not in this commit)
o remove old WI compatibility ioctls (wicontrol is officially dead)
o change the data structures returned for get sta info and get scan
results so future additions will not break user apps
o fixed tx rate is now maintained internally as an ieee rate and not an
index into the rate set; this needs to be extended to deal with
multi-mode operation
o add extended channel specifications to radiotap to enable 11n sniffing

Drivers:
o ath: add support for bg scanning, tx fragmentation, fast frames,
dynamic turbo (lightly tested), 11n (sniffing only and needs
new hal)
o awi: compile tested only
o ndis: lightly tested
o ipw: lightly tested
o iwi: add support for bg scanning (well tested but may have some
rough edges)
o ral, ural, rum: add suppoort for bg scanning, calibrate rssi data
o wi: lightly tested

This work is based on contributions by Atheros, kmacy, sephe, thompsa,
mlaier, kevlo, and others. Much of the scanning work was supported by
Atheros. The 11n work was supported by Marvell.