Commit Graph

253 Commits

Author SHA1 Message Date
Luciano Coelho
208c72f4fe nl80211: fix check for valid SSID size in scan operations
In both trigger_scan and sched_scan operations, we were checking for
the SSID length before assigning the value correctly.  Since the
memory was just kzalloc'ed, the check was always failing and SSID with
over 32 characters were allowed to go through.

This was causing a buffer overflow when copying the actual SSID to the
proper place.

This bug has been there since 2.6.29-rc4.

Cc: stable@kernel.org
Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-26 15:43:28 -04:00
Luciano Coelho
a2cd43c52a nl80211: remove some stack variables in trigger_scan and start_sched_scan
Some stack variables (name *ssid and *channel) are only used to define
the size of the memory block that needs to be allocated for the
request structure in the nl80211_trigger_scan() and
nl80211_start_sched_scan() functions.

This is unnecessary because the sizes of the actual elements in the
structure can be used instead.

Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-19 13:54:17 -04:00
Javier Cardona
57cf8043a6 nl80211: Move peer link state definition to nl80211
These definitions need to be exposed now that we can set the peer link
states via NL80211_ATTR_STA_PLINK_STATE.  They were already being
(opaquely) reported by NL80211_STA_INFO_PLINK_STATE.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-16 14:10:49 -04:00
Johannes Berg
7527a782e1 cfg80211: advertise possible interface combinations
Add the ability to advertise interface combinations in nl80211.
This allows the driver to indicate what the combinations are
that it supports. "Combinations" of just a single interface are
implicit, as previously. Note that cfg80211 will enforce that
the restrictions are met, but not for all drivers yet (once all
drivers are updated, we can remove the flag and enforce for all).

When no combinations are actually supported, an empty list will
be exported so that userspace can know if the kernel exported
this info or not (although it isn't clear to me what tools using
the info should do if the kernel didn't export it).

Since some interface types are purely virtual/software and don't
fit the restrictions, those are exposed in a new list of pure SW
types, not subject to restrictions. This mainly exists to handle
AP-VLAN and monitor interfaces in mac80211.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-16 14:10:40 -04:00
Johannes Berg
56d1893d94 cfg80211: restrict AP beacon intervals
Multiple virtual AP interfaces can currently try
to use different beacon intervals, but that just
leads to problems since it won't actually be done
that way by drivers. Return an error in this case
to make sure it won't be done wrong.

Also, ignore attempts to change the DTIM period
or beacon interval during the lifetime of the BSS.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-12 14:10:47 -04:00
Luciano Coelho
bbe6ad6dcb cfg80211/nl80211: add interval attribute for scheduled scans
Introduce NL80211_ATTR_SCHED_SCAN_INTERVAL as a required attribute for
NL80211_CMD_START_SCHED_SCAN.  This value informs the driver at which
intervals the scheduled scan cycles should be executed.

Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-11 15:12:27 -04:00
Luciano Coelho
807f8a8c30 cfg80211/nl80211: add support for scheduled scans
Implement new functionality for scheduled scan offload.  With this feature we
can scan automatically at certain intervals.

The idea is that the hardware can perform scan automatically and filter on
desired results without waking up the host unnecessarily.

Add NL80211_CMD_START_SCHED_SCAN and NL80211_CMD_STOP_SCHED_SCAN
commands to the nl80211 interface.  When results are available they are
reported by NL80211_CMD_SCHED_SCAN_RESULTS events.  The userspace is
informed when the scheduled scan has stopped with a
NL80211_CMD_SCHED_SCAN_STOPPED event, which can be triggered either by
the driver or by a call to NL80211_CMD_STOP_SCHED_SCAN.

Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-11 15:12:26 -04:00
Javier Cardona
1833d81a12 mac80211: allow setting supported rates on mesh peers
This is necessary for userspace managed stations.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-11 14:50:36 -04:00
Thomas Pedersen
8429828ec9 nl80211: allow setting MFP flag for a meshif
Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-11 14:44:47 -04:00
Thomas Pedersen
ff973af74a nl80211: allow installing keys for a meshif
Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-11 14:44:47 -04:00
Javier Cardona
9c3990aaec nl80211: Let userspace drive the peer link management states.
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-11 14:44:46 -04:00
Javier Cardona
b130e5cec9 nl80211: Introduce NL80211_MESH_SETUP_USERSPACE_AMPE
Introduce a new configuration option to support AMPE from userspace.

Prior to this series we only supported authentication in userspace: an
authentication daemon would authenticate peer candidates in userspace
and hand them over to the kernel.  From that point the mesh stack would
take over and establish a peer link (Mesh Peering Management).

These patches introduce support for Authenticated Mesh Peering Exchange
in userspace.  The userspace daemon implements the AMPE protocol and on
successfull completion create mesh peers and install encryption keys.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-11 14:37:47 -04:00
Johannes Berg
ff1b6e69ad nl80211/cfg80211: WoWLAN support
This is based on (but now quite far from) the
original work from Luis and Eliad. Add support
for configuring WoWLAN triggers, and getting
the configuration out again. Changes from the
original patchset are too numerous to list,
but one important change needs highlighting:
the suspend() callback is passed NULL for the
trigger configuration if userspace has not
configured WoWLAN at all.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-05 14:59:19 -04:00
Jouni Malinen
0e579d6a8f nl80211: Fix set_key regression with some drivers
Commit dbd2fd656f added a mechanism for
user space to indicate whether a default key is being configured for
only unicast or only multicast frames instead of all frames. This
commit added a driver capability flag for indicating whether separate
default keys are supported and validation of the set_key command based
on that capability.

However, this single capability flag is not enough to cover possible
difference based on mode (AP/IBSS/STA) and the way this change was
introduced resulted in a regression with drivers that do not indicate
the new capability (i.e.., more or less any non-mac80211 driver using
cfg80211) when using a recent wpa_supplicant snapshot.

Fix the regression by removing the new check which is not strictly
speaking needed. The new separate default key functionality is needed
only for RSN IBSS which has a separate capability indication.

Cc: stable@kernel.org
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-05-05 14:59:16 -04:00
Mohammed Shafi Shajakhan
ebe27c91af {mac|nl}80211: Add station connected time
Add station connected time in debugfs. This will be helpful to get a
measure of stability of the connection and for debugging stress issues

Cc: Senthilkumar Balasubramanian <Senthilkumar.Balasubramanian@Atheros.com>
Signed-off-by: Mohammed Shafi Shajakhan <mshajakhan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-04-12 16:58:47 -04:00
Javier Cardona
c93b5e717e nl80211: New notification to discover mesh peer candidates.
Notify userspace when a beacon/presp is received from a suitable mesh
peer candidate for whom no sta information exists.  Userspace can then
decide to create a sta info for the candidate.  If userspace is not
ready to authenticate the peer right away, it can create the sta info
with the authenticated flag unset and set it later.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-04-12 16:57:39 -04:00
Javier Cardona
96b78dff03 nl80211/mac80211: Perform PLINK_ACTION on new station
Modify the NEW_STATION command to accept PLINK_ACTIONS, in case
userspace wants to create stations and initiate a peer link right away
(for authenticated stations) or create a blocked station (for
debugging).

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-04-12 16:57:39 -04:00
Javier Cardona
b39c48fac1 nl80211/mac80211: let userspace authenticate stations
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-04-12 16:57:38 -04:00
Javier Cardona
15d5dda623 cfg80211/nl80211: Add userspace authentication flag to mesh setup
During mesh setup, use NL80211_MESH_SETUP_USERSPACE_AUTH flag to create
a secure mesh and route management frames to userspace.

Also, NL80211_CMD_GET_WIPHY now returns a flag NL80211_SUPPORT_MESH_AUTH
if the wiphy's mesh implementation supports routing of mesh auth frames
to userspace.  This is useful for forward compatibility between old
kernels and new userspace tools.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-04-12 16:57:37 -04:00
Javier Cardona
581a8b0fee nl80211: rename NL80211_MESH_SETUP_VENDOR_PATH_SEL_IE
To NL80211_MESH_SETUP_IE. This reflects our ability to insert any ie
into a mesh beacon, not simply path selection ies.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-04-12 16:57:37 -04:00
Paul Stewart
f4263c9857 nl80211: Add BSS parameters to station
This allows user-space monitoring of BSS parameters for the associated
station.  This is useful for debugging and verifying that the paramaters
are as expected.

[Exactly the same as before but bundled into a single message]

Signed-off-by: Paul Stewart <pstew@chromium.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-04-07 15:34:12 -04:00
Jouni Malinen
ec15e68ba6 cfg80211: Add nl80211 event for deletion of a station entry
Indicate an NL80211_CMD_DEL_STATION event when a station entry in
mac80211 is deleted to match with the NL80211_CMD_NEW_STATION event
that is used when the entry was added. This is needed, e.g., to allow
user space to remove a peer from RSN IBSS Authenticator state machine
to avoid re-authentication and re-keying delays when the peer is not
reachable anymore.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-03-30 14:15:18 -04:00
Felix Fietkau
c8dcfd8a04 cfg80211: add a field for the bitrate of the last rx data packet from a station
Also fix a typo in the STATION_INFO_TX_BITRATE description

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-03-01 13:48:21 -05:00
Julia Lawall
efe1cf0c57 net/wireless/nl80211.c: Avoid call to genlmsg_cancel
genlmsg_cancel subtracts some constants from its second argument before
calling nlmsg_cancel.  nlmsg_cancel then calls nlmsg_trim on the same
arguments.  nlmsg_trim tests for NULL before doing any computation, but a
NULL second argument to genlmsg_cancel is no longer NULL due to the initial
subtraction.  Nothing else happens in this execution, so the call to
genlmsg_cancel is simply unnecessary in this case.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression data;
@@

if (data == NULL) { ...
* genlmsg_cancel(..., data);
  ...
  return ...;
}
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-01-28 15:46:23 -05:00
Bruno Randolf
39fd5de447 nl80211: Export available antennas
Export the information which antennas are available for configuration as TX or
RX antennas via nl80211.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-20 14:49:47 -05:00
Bruno Randolf
7f531e03ab cfg80211: Separate available antennas for RX and TX
As has been pointed out by Daniel Halperin some devices (e.g. Intel IWL5100)
can only TX from a subset of RX antennas, so use separate availability masks
for RX and TX.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-20 14:46:58 -05:00
Javier Cardona
c7108a7111 mac80211: Send mesh non-HWMP path selection frames to userspace
Let path selection frames for protocols other than HWMP be sent to
userspace via NL80211_CMD_REGISTER_FRAME.  Also allow userspace to send
and receive mesh path selection frames.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-20 14:46:58 -05:00
Javier Cardona
c80d545da3 mac80211: Let userspace enable and configure vendor specific path selection.
Userspace will now be allowed to toggle between the default path
selection algorithm (HWMP, implemented in the kernel), and a vendor
specific alternative.  Also in the same patch, allow userspace to add
information elements to mesh beacons.  This is accordance with the
Extensible Path Selection Framework specified in version 7.0 of the
802.11s draft.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-20 14:46:57 -05:00
Javier Cardona
24bdd9f4c9 mac80211: Rename mesh_params to mesh_config to prepare for mesh_setup
Mesh parameters can be to setup a mesh or to configure it.
This patch renames the ambiguous name mesh_params to mesh_config
in preparation for mesh_setup.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-20 14:46:57 -05:00
Jouni Malinen
cf4e594ea7 nl80211: Add notification for dropped Deauth/Disassoc
Add a new notification to indicate that a received, unprotected
Deauthentication or Disassociation frame was dropped due to
management frame protection being in use. This notification is
needed to allow user space (e.g., wpa_supplicant) to implement
SA Query procedure to recover from association state mismatch
between an AP and STA.

This is needed to avoid getting stuck in non-working state when MFP
(IEEE 802.11w) is used and a protected Deauthentication or
Disassociation frame is dropped for any reason. After that, the
station would silently discard any unprotected Deauthentication or
Disassociation frame that could be indicating that the AP does not
have association for the STA (when the Reason Code would be 6 or 7).
IEEE Std 802.11w-2009, 11.13 describes this recovery mechanism.

Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-16 15:22:30 -05:00
Johannes Berg
a293911d4f nl80211: advertise maximum remain-on-channel duration
With the upcoming hardware offload implementation,
some devices will have a different maximum duration
for the remain-on-channel command. Advertise the
maximum duration in mac80211, and make mac80211 set
it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-15 17:03:56 -05:00
Johannes Berg
dbd2fd656f cfg80211/nl80211: separate unicast/multicast default TX keys
Allow userspace to specify that a given key
is default only for unicast and/or multicast
transmissions. Only WEP keys are for both,
WPA/RSN keys set here are GTKs for multicast
only. For more future flexibility, allow to
specify all combiations.

Wireless extensions can only set both so use
nl80211; WEP keys (connect keys) must be set
as default for both (but 802.1X WEP is still
possible).

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-13 15:23:28 -05:00
Bruno Randolf
a7ffac9591 cfg80211: Add antenna availability information
Add a field to wiphy for the hardware to report the availble antennas for
configuration. Only if this is set to something bigger than zero, will the
anntenna configuration ops be executed.

Allthough this could be a simple number of antennas, I defined it as a bitmap
of antennas which are available for configuration, since it's more consistent
with the rest of the antenna API and there could be cases where the
hardware allows only configuration of certain antennas. As it does not make
much of a difference in size or normal usage, I think it's better to be able to
support this, in case the need arises.

The antenna configuration is now also checked against the availabe antennas and
rejected if it does not match.

Signed-off-by: Bruno Randolf <br1@einfach.org>

--
v3:	always apply available antenna mask (for "all" antennas case).

v2:	reject antenna configurations which don't match the available antennas
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-13 15:23:27 -05:00
Helmut Schaa
50b12f597b cfg80211: Add new BSS attribute ht_opmode
Add a new BSS attribute to allow hostapd to set the current HT opmode.
Otherwise drivers won't be able to set up protection for HT rates in
AP mode.

Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-08 15:38:43 -05:00
Bruno Randolf
541a45a142 nl80211/mac80211: Report signal average
Extend nl80211 to report an exponential weighted moving average (EWMA) of the
signal value. Since the signal value usually fluctuates between different
packets, an average can be more useful than the value of the last packet.

This uses the recently added generic EWMA library function.

--
v2:	fix ABI breakage and change factor to be a power of 2.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-07 16:09:12 -05:00
Johannes Berg
29cbe68c51 cfg80211/mac80211: add mesh join/leave commands
Instead of tying mesh activity to interface up,
add join and leave commands for mesh. Since we
must be backward compatible, let cfg80211 handle
joining a mesh if a mesh ID was pre-configured
when the device goes up.

Note that this therefore must modify mac80211 as
well since mac80211 needs to lose the logic to
start the mesh on interface up.

We now allow querying mesh parameters before the
mesh is connected, which simply returns defaults.
Setting them (internally renamed to "update") is
only allowed while connected. Specify them with
the new mesh join command instead where needed.

In mac80211, beaconing must now also follow the
mesh enabled/not enabled state, which is done
by testing the mesh ID.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-06 16:01:29 -05:00
Johannes Berg
bd90fdcc5f nl80211: refactor mesh parameter parsing
I'm going to need this in a new place later.

Tested-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-06 16:01:29 -05:00
Johannes Berg
f9e10ce4cf cfg80211: require add_virtual_intf to return new dev
cfg80211 used to do all its bookkeeping in
the notifier, but some new stuff will have
to use local variables so make the callback
return the netdev pointer.

Tested-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-06 16:01:28 -05:00
Javier Cardona
45904f2165 nl80211/mac80211: define and allow configuring mesh element TTL
The TTL in path selection information elements is different from
the mesh ttl used in mesh data frames.  Version 7.03 of the 11s
draft calls this ttl 'Element TTL'.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-12-06 16:01:28 -05:00
Johannes Berg
f7ca38dfe5 nl80211/cfg80211: extend mgmt-tx API for off-channel
With p2p, it is sometimes necessary to transmit
a frame (typically an action frame) on another
channel than the current channel. Enable this
through the CMD_FRAME API, and allow it to wait
for a response. A new command allows that wait
to be aborted.

However, allow userspace to specify whether or
not it wants to allow off-channel TX, it may
actually want to use the same channel only.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-11-29 15:24:35 -05:00
Johannes Berg
c063dbf52b cfg80211: allow using CQM event to notify packet loss
This adds the ability for drivers to use CQM events
to notify about packet loss for specific stations
(which could be the AP for the managed mode case).
Since the threshold might be determined by the
driver (it isn't passed in right now) it will be
passed out of the driver to userspace in the event.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-11-24 16:19:36 -05:00
Felix Fietkau
dd5b4cc71c cfg80211/mac80211: improve ad-hoc multicast rate handling
- store the multicast rate as an index instead of the rate value
  (reduces cpu overhead in a hotpath)
- validate the rate values (must match a bitrate in at least one sband)

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-11-24 16:19:35 -05:00
John W. Linville
d7a066c923 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6 2010-11-24 16:19:24 -05:00
John W. Linville
ccb1435401 Revert "nl80211/mac80211: Report signal average"
This reverts commit 86107fd170.

This patch inadvertantly changed the userland ABI.

Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-11-24 16:18:36 -05:00
Bruno Randolf
86107fd170 nl80211/mac80211: Report signal average
Extend nl80211 to report an exponential weighted moving average (EWMA) of the
signal value. Since the signal value usually fluctuates between different
packets, an average can be more useful than the value of the last packet.

This uses the recently added generic EWMA library function.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-11-18 14:22:20 -05:00
Felix Fietkau
885a46d0f7 cfg80211: add support for setting the ad-hoc multicast rate
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-11-16 16:39:08 -05:00
Bruno Randolf
afe0cbf875 cfg80211: Add nl80211 antenna configuration
Allow setting of TX and RX antennas configuration via nl80211.

The antenna configuration is defined as a bitmap of allowed antennas to use.
This API can be used to mask out antennas which are not attached or should not
be used for other reasons like regulatory concerns or special setups.

Separate bitmaps are used for RX and TX to allow configuring different antennas
for receiving and transmitting. Each bitmap is 32 bit long, each bit
representing one antenna, starting with antenna 1 at the first bit. If an
antenna bit is set, this means the driver is allowed to use this antenna for RX
or TX respectively; if the bit is not set the hardware is not allowed to use
this antenna.

Using bitmaps has the benefit of allowing for a flexible configuration
interface which can support many different configurations and which can be used
for 802.11n as well as non-802.11n devices. Instead of relying on some hardware
specific assumptions, drivers can use this information to know which antennas
are actually attached to the system and derive their capabilities based on
that.

802.11n devices should enable or disable chains, based on which antennas are
present (If all antennas belonging to a particular chain are disabled, the
entire chain should be disabled). HT capabilities (like STBC, TX Beamforming,
Antenna selection) should be calculated based on the available chains after
applying the antenna masks. Should a 802.11n device have diversity antennas
attached to one of their chains, diversity can be enabled or disabled based on
the antenna information.

Non-802.11n drivers can use the antenna masks to select RX and TX antennas and
to enable or disable antenna diversity.

While covering chainmasks for 802.11n and the standard "legacy" modes "fixed
antenna 1", "fixed antenna 2" and "diversity" this API also allows more rare,
but useful configurations as follows:

1) Send on antenna 1, receive on antenna 2 (or vice versa). This can be used to
have a low gain antenna for TX in order to keep within the regulatory
constraints and a high gain antenna for RX in order to receive weaker signals
("speak softly, but listen harder"). This can be useful for building long-shot
outdoor links. Another usage of this setup is having a low-noise pre-amplifier
on antenna 1 and a power amplifier on the other antenna. This way transmit
noise is mostly kept out of the low noise receive channel.
(This would be bitmaps: tx 1 rx 2).

2) Another similar setup is: Use RX diversity on both antennas, but always send
on antenna 1. Again that would allow us to benefit from a higher gain RX
antenna, while staying within the legal limits.
(This would be: tx 0 rx 3).

3) And finally there can be special experimental setups in research and
development even with pre 802.11n hardware where more than 2 antennas are
available. It's good to keep the API simple, yet flexible.

Signed-off-by: Bruno Randolf <br1@einfach.org>

--
v7:	Made bitmasks 32 bit wide and rebased to latest wireless-testing.
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-11-16 16:37:05 -05:00
Felix Fietkau
3cc25e510d cfg80211: fix a crash in dev lookup on dump commands
IS_ERR and PTR_ERR were called with the wrong pointer, leading to a
crash when cfg80211_get_dev_from_ifindex fails.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-11-08 16:53:47 -05:00
Felix Fietkau
8610c29a2c cfg80211: add channel utilization stats to the survey command
Using these, user space can calculate a relative channel utilization
with arbitrary intervals by regularly taking snapshots of the survey
results.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-10-11 15:04:20 -04:00
Johannes Berg
388ac775be cfg80211: constify WDS address
There's no need for the WDS peer address
to not be const, so make it const.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-10-07 14:41:28 -04:00