The driver is never informed about monitor or
AP_VLAN interfaces, so whenever we pass those
to it later this is a bug. Verify we don't as
there are some cases where this could happen.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
tx params should be configured per interface.
add ieee80211_vif param to the conf_tx callback,
and change all the drivers that use this callback.
The following spatch was used:
@rule1@
struct ieee80211_ops ops;
identifier conf_tx_op;
@@
ops.conf_tx = conf_tx_op;
@rule2@
identifier rule1.conf_tx_op;
identifier hw, queue, params;
@@
conf_tx_op (
- struct ieee80211_hw *hw,
+ struct ieee80211_hw *hw, struct ieee80211_vif *vif,
u16 queue,
const struct ieee80211_tx_queue_params *params) {...}
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
iwlwifi needs to know the number of frames that are
going to be sent to a station while it is asleep so
it can properly handle the uCode blocking of that
station.
Before uAPSD, we got by by telling the device that
a single frame was going to be released whenever we
encountered IEEE80211_TX_CTL_POLL_RESPONSE. With
uAPSD, however, that is no longer possible since
there could be more than a single frame.
To support this model, add a new callback to notify
drivers when frames are going to be released.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
If there are frames for a station buffered in
the driver, mac80211 announces those in the TIM
IE but there's no way to release them. Add new
API to release such frames and use it when the
station polls for a frame.
Since the API will soon also be used for uAPSD
it is easily extensible.
Note that before this change drivers announcing
driver-buffered frames in the TIM bit actually
will respond to a PS-Poll with a potentially
lower priority frame (if there are any frames
buffered in mac80211), after this patch a driver
that hasn't been changed will no longer respond
at all. This only affects ath9k, which will need
to be fixed to implement the new API.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
save and configure tx param per sdata, rather than
per hardware.
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
TSF can be kept per vif.
Add ieee80211_vif param to set/get/reset_tsf, and move
the debugfs entries to the per-vif directory.
Update all the drivers that implement these callbacks.
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
For iwlwifi, I decided not to use this API since
it just increased the complexity for little gain.
Since nobody else intends to use it, let's kill
it again. If anybody later needs to have it, we
can always revive it then.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
In P2P client mode, the GO (AP) to connect to might
have periods of time where it is not available due
to powersave. To allow the driver to sync with it
and send frames to the GO only when it is available
add a new callback tx_sync (and the corresponding
finish_tx_sync). These callbacks can sleep unlike
the actual TX.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
mac80211 maintains a running average of the RSSI when a STA
is associated to an AP. Report threshold events to any driver
that has registered callbacks for getting RSSI measurements.
Implement callbacks in mac80211 so that driver can set thresholds.
Add callbacks in mac80211 which is invoked when an RSSI threshold
event occurs.
mac80211: add tracing to rssi_reports api and remove extraneous fn argument
mac80211: scale up rssi thresholds from driver by 16 before storing
Signed-off-by: Meenakshi Venkataraman <meenakshi.venkataraman@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This adds the necessary mac80211 APIs to support
GTK rekey offload, mirroring the functionality
from cfg80211.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When suspending, __ieee80211_suspend() calls ieee80211_scan_cancel(),
which will only cancel sw scan. In order to cancel hw scan, the
low-level driver has to cancel it in the suspend() callback. however,
this is too late, as a new scan_work will be enqueued (while the driver
is going into suspend).
Add a new cancel_hw_scan() callback, asking the driver to cancel an
active hw scan, and call it in ieee80211_scan_cancel().
Signed-off-by: Eliad Peller <eliad@wizery.com>
Reviewed-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Implement support for HW scheduled scan. The mac80211 code doesn't perform
scheduled scans itself, but calls the driver to start and stop scheduled
scans.
This patch also creates a trace event class to be used by drv_hw_scan
and the new drv_sched_scan_start and drv_sched_stop functions, in
order to avoid duplicate code.
Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This adds basic support for the new WoWLAN
configuration in mac80211. The behaviour is
completely offloaded to the driver though,
with two new callbacks (suspend/resume).
Options for the driver include a complete
reconfiguration after wakeup, and exposing
all the triggers it wants to support.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This patch adds a new API for setting a TX rate mask in
drivers that have rate control in either the firmware or hardware.
This can be used for various purposes, for example, masking out the
11b rates in P2P operation.
Signed-off-by: Sujith Manoharan <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
In a highly noisy environment, the tx rate of the driver drops and
the application slows down since it has not yet received ACKs for
the frames already queued in the hardware. Since this ACK may take
more than 100ms, stopping the dev queues for entering PS at this
stage breaks applications, WMM test cases in my testing.
If there are frames already pending in the tx queue, postponing the
PS logic helps to avoid redundant queue stops. When power save is
enabled by default and in a noisy environment, this API certainly
helps in improving the average throughput.
Signed-off-by: Vivek Natarajan <vnatarajan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
For devices supported by iwlwifi sometimes
off-channel transmissions need to be handled
by the device completely. To support this
mac80211 needs to pass the frame directly
to the driver and not through the TX path
as the driver needs the frame and channel
information at the same time.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The return value of the tx operation is commonly
misused by drivers, leading to errors. All drivers
will drop frames if they fail to TX the frame, and
they must also properly manage the queues (if they
didn't, mac80211 would already warn).
Removing the ability for drivers to return a BUSY
value also allows significant cleanups of the TX
TX handling code in mac80211.
Note that this also fixes a bug in ath9k_htc, the
old "return -1" there was wrong.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Tested-by: Sedat Dilek <sedat.dilek@googlemail.com> [ath5k]
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com> [rt2x00]
Acked-by: Larry Finger <Larry.Finger@lwfinger.net> [b43, rtl8187, rtlwifi]
Acked-by: Luciano Coelho <coelho@ti.com> [wl12xx]
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The aggregation code currently doesn't implement the
buffer size negotiation. It will always request a max
buffer size (which is fine, if a little pointless, as
the mac80211 code doesn't know and might just use 0
instead), but if the peer requests a smaller size it
isn't possible to honour this request.
In order to fix this, look at the buffer size in the
addBA response frame, keep track of it and pass it to
the driver in the ampdu_action callback when called
with the IEEE80211_AMPDU_TX_OPERATIONAL action. That
way the driver can limit the number of subframes in
aggregates appropriately.
Note that this doesn't fix any drivers apart from the
addition of the new argument -- they all need to be
updated separately to use this variable!
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This allows drivers to support remain-on-channel
offload if they implement smarter timing or need
to use a device implementation like iwlwifi.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The 802.11 spec states that the STA that generated the last Beacon frame shall
be the STA that response to a probe request. This is important for congestion
reduction when a probe request is received - only 1 node in an adhoc BSS
will transmit a response. While mac80211 drivers should provide the
tx_last_beacon function to report if they transmitted the last beacon many
do not. As an attempt to reduce probe response congestion default this
to 0 such that a node not implementing this capability does not contribute
to unnecessary congestion.
In a modern medium sized office environment I see upwards of 100 probe
requests per second received at a given node from various hardware/OS/drivers
doing zeroconf 'active probing' as opposed to passively listening for beacons.
With a modest 10-node adhoc network consisting of drivers that do not implement
this tx_last_beacon feature, I have seen this result in the simultaneous xmit
of probe responses accumulating to 500 probe responses per second because of
collisions which brings the adhoc network to its knees as well as causes
needless congestion.
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Allow antenna configuration by calling driver's function for it.
We disallow antenna configuration if the wiphy is already running, mainly to
make life easier for 802.11n drivers which need to recalculate HT capabilites.
Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The lower driver is notified when the fragmentation threshold changes
and upon a reconfig of the interface.
If the driver supports hardware TX fragmentation, don't fragment
packets in the stack.
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When a driver advertises p2p device support,
mac80211 will handle it, but internally it will
rewrite the interface type to STA/AP rather than
P2P-STA/GO since otherwise a lot of paths need
to be touched that are otherwise identical. A
p2p boolean tells drivers whether or not a given
interface will be used for p2p or not.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Add support to mac80211 for changing the interface
type even when the interface is UP, if the driver
supports it.
To achieve this
* add a new driver callback for switching,
* split some of the interface up/down code out
into new functions (do_open/do_stop), and
* maintain an own __SDATA_RUNNING bit that will
not be set during interface type, so that any
other code doesn't use the interface.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
There is a circular locking dependency when configuring the
hardware ARP filters on association, occurring when flushing the mac80211
workqueue. This is what happens:
[ 92.026800] =======================================================
[ 92.030507] [ INFO: possible circular locking dependency detected ]
[ 92.030507] 2.6.34-04781-g2b2c009 #85
[ 92.030507] -------------------------------------------------------
[ 92.030507] modprobe/5225 is trying to acquire lock:
[ 92.030507] ((wiphy_name(local->hw.wiphy))){+.+.+.}, at: [<ffffffff8105b5c0>] flush_workq
ueue+0x0/0xb0
[ 92.030507]
[ 92.030507] but task is already holding lock:
[ 92.030507] (rtnl_mutex){+.+.+.}, at: [<ffffffff812b9ce2>] rtnl_lock+0x12/0x20
[ 92.030507]
[ 92.030507] which lock already depends on the new lock.
[ 92.030507]
[ 92.030507]
[ 92.030507] the existing dependency chain (in reverse order) is:
[ 92.030507]
[ 92.030507] -> #2 (rtnl_mutex){+.+.+.}:
[ 92.030507] [<ffffffff810761fb>] lock_acquire+0xdb/0x110
[ 92.030507] [<ffffffff81341754>] mutex_lock_nested+0x44/0x300
[ 92.030507] [<ffffffff812b9ce2>] rtnl_lock+0x12/0x20
[ 92.030507] [<ffffffffa022d47c>] ieee80211_assoc_done+0x6c/0xe0 [mac80211]
[ 92.030507] [<ffffffffa022f2ad>] ieee80211_work_work+0x31d/0x1280 [mac80211]
[ 92.030507] -> #1 ((&local->work_work)){+.+.+.}:
[ 92.030507] [<ffffffff810761fb>] lock_acquire+0xdb/0x110
[ 92.030507] [<ffffffff8105a51a>] worker_thread+0x22a/0x370
[ 92.030507] [<ffffffff8105ecc6>] kthread+0x96/0xb0
[ 92.030507] [<ffffffff81003a94>] kernel_thread_helper+0x4/0x10
[ 92.030507]
[ 92.030507] -> #0 ((wiphy_name(local->hw.wiphy))){+.+.+.}:
[ 92.030507] [<ffffffff81075fdc>] __lock_acquire+0x1c0c/0x1d50
[ 92.030507] [<ffffffff810761fb>] lock_acquire+0xdb/0x110
[ 92.030507] [<ffffffff8105b60e>] flush_workqueue+0x4e/0xb0
[ 92.030507] [<ffffffffa023ff7b>] ieee80211_stop_device+0x2b/0xb0 [mac80211]
[ 92.030507] [<ffffffffa0231635>] ieee80211_stop+0x3e5/0x680 [mac80211]
The locking in this case is quite complex. Fix the problem by rewriting the
way the hardware ARP filter list is handled - i.e. make a copy of the address
list to the bss_conf struct, and provide that list to the hardware driver
when needed.
The current patch will enable filtering also in promiscuous mode. This may need
to be changed in the future.
Reported-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Currently, driver tracing is sometimes invoked
after and sometimes before the actual driver
callback. This is fine as long as the driver
has no tracing itself, but as soon as it does
it gets confusing.
To make traces containing such information
easier to read, introduce a return tracer in
mac80211 that essentially brackets any driver
tracing, and invoke the real trace before the
driver's callback, only showing the return
value, if any, afterwards.
Since tracing records the process, there's no
problem with overlapping calls if that should
happen.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Allow drivers to sleep, and indicate this in
the documentation. ath9k has some locking I
don't understand, so keep it safe and disable
BHs in it, all other drivers look fine with
the context change.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
To prepare for allowing drivers to sleep in
ampdu_action, change the locking in the TX
aggregation code to use the mutex the RX part
already uses. The spinlock is still necessary
around some code to avoid races with TX, but
now we can also synchronize_net() to avoid
getting an inconsistent sequence number.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
To prepare for allowing drivers to sleep in
ampdu_action, change the locking in the RX
aggregation code to use a mutex, so that it
would already allow drivers to sleep. But
explicitly disable BHs around the callback
for now since the TX part cannot yet sleep,
and drivers' locking might require it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This makes "iw wlan0 dump survey" work again with
mac80211-based drivers that support it, e.g. ath5k.
Signed-off-by: Holger Schurig <holgerschurig@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
STA_NOTIFY_ADD and STA_NOTIFY_REMOVE have no users anymore,
and station addition/removal are indicated to drivers
using sta_add() and sta_remove(), which can sleep.
Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Some hardware allow extended filtering of ARP frames not intended for
the host. To perform such filtering, the hardware needs to know the current
IP address(es) of the host, bound to its interface.
Add support for ARP filtering to mac80211 by adding a new op to the driver
interface, allowing to configure the current IP addresses. This op is called
upon association with the currently configured address(es), and when
associated whenever the IP address(es) change.
This patch adds configuration of IPv4 addresses only, as IPv6 addresses don't
need ARP filtering.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This adds support for offloading the channel switch
operation to devices that support such, typically
by having specific firmware API for it. The reasons
for this could be that the firmware provides better
timing or that regulatory enforcement done by the
device requires special handling of CSAs.
In order to allow drivers to specify the timing to
the device, the new channel_switch callback will
pass through the received frame's mactime, where
available.
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When scanning, it is somewhat important to scan
on the correct virtual interface. All drivers
that currently implement hw_scan only support a
single virtual interface, but that may change
and then we'd want to be ready.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This adds the survey function to both mac80211 itself and to mac80211_hwsim.
For the latter driver, we simply invent some noise level.A real driver which
cannot determine the real channel noise MUST NOT report any noise, especially
not a magically conjured one :-)
Signed-off-by: Holger Schurig <holgerschurig@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Converts the list and the core manipulating with it to be the same as uc_list.
+uses two functions for adding/removing mc address (normal and "global"
variant) instead of a function parameter.
+removes dev_mcast.c completely.
+exposes netdev_hw_addr_list_* macros along with __hw_addr_* functions for
manipulation with lists on a sandbox (used in bonding and 80211 drivers)
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
get_tx_stats() driver operation is not currently used anywhere in mac80211
and there are no plans to use it in the not-so-near future. So it can go
without anyone missing it.
Signed-off-by: Kalle Valo <kalle.valo@iki.fi>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Many drivers would like to sleep during station
addition and removal, and currently have a high
complexity there from not being able to.
This introduces two new callbacks sta_add() and
sta_remove() that drivers can implement instead
of using sta_notify() and that can sleep, and
the new sta_add() callback is also allowed to
fail.
The reason we didn't do this previously is that
the IBSS code wants to insert stations from the
RX path, which is a tasklet, so cannot sleep.
This patch will keep the station allocation in
that path, but moves adding the station to the
driver out of line. Since the addition can now
fail, we can have IBSS peer structs the driver
rejected -- in that case we still talk to the
station but never tell the driver about it in
the control.sta pointer. If there will ever be
a driver that has a low limit on the number of
stations and that cannot talk to any stations
that are not known to it, we need to do come up
with a new strategy of handling larger IBSSs,
maybe quicker expiry or rejecting peers.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Johannes noticed that I had incorrectly documented the context of
update_tkip_key() driver operation. It must be atomic because all
RX code is run inside rcu critical section.
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Kalle Valo <kalle.valo@iki.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When a TKIP key is updated, we should pass the station
pointer instead of just the address, since drivers can
use that to store their own data. We also need to pass
the virtual interface pointer.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Mac80211 callback to driver set_coverage_class() sets slot time and ACK
timeout for given IEEE 802.11 coverage class. The callback is optional,
but it's essential for long distance links.
Signed-off-by: Lukas Turek <8an@praha12.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
To make it easier to notice cases of calling sleeping ops in atomic context,
annotate driver-ops.h with appropiate might_sleep() calls. At the same time,
also document in mac80211.h the op functions with missing contexts.
mac80211 doesn't seem to use get_tx_stats anywhere currently. Just to be on
the safe side, I documented it to be atomic, but hopefully the op can be
removed in the future.
Compile-tested only.
Signed-off-by: Kalle Valo <kalle.valo@iki.fi>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
All its members (vif, mac_addr, type) are now available
in the vif struct directly, so we can pass that instead
of the conf struct. I generated this patch (except the
mac80211 and header file changes) with this semantic
patch:
@@
identifier conf, fn, hw;
type tp;
@@
tp fn(struct ieee80211_hw *hw,
-struct ieee80211_if_init_conf *conf)
+struct ieee80211_vif *vif)
{
<...
(
-conf->type
+vif->type
|
-conf->mac_addr
+vif->addr
|
-conf->vif
+vif
)
...>
}
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
We've long lacked a good confirmation that frames
have really gone out, e.g. before going off-channel
for a scan. Add a flush() operation that drivers
can implement to provide that confirmation, and use
it in a few places:
* before scanning sends the nullfunc frames
* after scanning sends the nullfunc frames, if any
* when going idle, to send any pending frames
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
It's not all that useful to have the vif/sdata pointer,
we'd rather refer to the interfaces by their name.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
For bluetooth 3, we will most likely not have
a netdev for a virtual interface (sdata), so
prepare for that by reducing the reliance on
having a netdev. This patch moves the name
and address fields into the sdata struct and
uses them from there all over. Some work is
needed to keep them sync'ed, but that's not
a lot of work and in slow paths anyway.
In doing so, this also reduces the number of
pointer dereferences in many places, because
of things like sdata->dev->dev_addr becoming
sdata->vif.addr.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The entire aggregation code currently operates on the
hw pointer and station addresses, but that needs to
change to make stations purely per-vif; As one step
preparing for that make the aggregation code callable
with the station, or by the combination of virtual
interface and station address.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Due to the way the tasklets work in mac80211 there's
no need to ever disable them.
However, we need to clear the pending packets when
taking down the last interface because otherwise
the tx_pending_tasklet might be queued if the
driver mucks with the queues (which it shouldn't).
I've had a situation occasionally with ar9170 in
which ksoftirq was using 100% CPU time because
a disabled tasklet was scheduled, and I think that
was due to ar9170 receiving a packet while the
tasklet was disabled. That's strange and it really
should not do that for other reasons, but there's
no need to waste that much CPU time over it, it
should just warn instead.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Johannes Berg