Without this, it is impossible to tell exactly which
MLME code returned the error.
Also, convert to wpa_dbg so that we get device names
in the messages.
Signed-hostap: Ben Greear <greearb@candelatech.com>
All we really need is the family ID, and we can
get that with genl_ctrl_resolve() and then don't
need to worry about family/cache objects.
Signed-hostap: Johannes Berg <johannes.berg@intel.com>
In scan.c, merge a channel's noise value into the scan results. When
comparing scan results, compute the signal-to-noise ratio and use it
when available. Prefer a 5 GHz network if its SNR is really big (> 30)
or if its SNR is relatively close to the other network's.
Instead of hardcoding IEEE 802.11b rates to be disabled whenever
P2P support is built in and supported by the driver, do this only
when an interface is set to P2P mode (both when adding a new
interface and when changing the interface mode). This re-enables
use of IEEE 802.11b APs with CONFIG_P2P=y builds.
Signed-hostap: Jouni Malinen <j@w1.fi>
This function was used unconditionally if wpa_supplicant build
includes CONFIG_P2P=y. Adding a separate driver_ops for such use
is not really useful since the driver wrappers can do the same
internally. Remove this driver_ops and move matching functionality
into driver_nl80211.c which was the only driver wrapper using
this driver_ops callback.
Signed-hostap: Jouni Malinen <j@w1.fi>
nl80211_disable_11b_rates() function was supposed to use the 'disabled'
parameter to figure out whether to disable or re-enable 802.11b rates.
In addition, the driver deinit path was now ending up re-disabling the
enabled rates at the end of the deinit operations when the interface
type was forced back to station. Both of these issues are now fixed
and the 2.4 GHz band TX rate index is cleared properly when
wpa_supplicant is stopped.
Signed-hostap: Jouni Malinen <j@w1.fi>
disable_11b_rates() is called on interface addition,
but not on interface type change, resulting in 11b rates
enabled on p2p interfaces.
Signed-off-by: Eliad Peller <eliad@wizery.com>
This can be used to apply the no-CCK rule conditionally depending on
which frame is being sent. The no-CCK rule applies only for P2P
management frames while SA Query and FT use cases do not have similar
restrictions.
Signed-hostap: Jouni Malinen <j@w1.fi>
Add a new attribute to specify whether to use CCK rate or not during
scan and sending management frames. This helps to send P2P probes
at non-CCK rate. This ensures that P2P probe request/response/action
frames are always sent at non-CCK rates.
Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
The netlink event processing is delayed since they are only returned
after control returns to eloop. This can result in netlink down events
being processed at a point when the interface has is actually still
there (the first event on new interface is down) and that can result in
odd behavior especially when the resulting interface-disabled event is
delivered to AP mode interface with wpa_supplicant.
Work around this by filtering netlink down events if the matching
interface is up at the time the netlink event is processed. This fixes
an issue brought up by commit 36d84860bb.
Before commencing setup, add a new STA entry to the driver representing
the peer. Later during setup, update the STA entry using information
received from the peer.
Extend sta_add() callback for adding/modifying a TDLS peer entry and
connect it to the TDLS state machine. Implement this callback for the
nl80211 driver and send peer information to kernel.
Mark TDLS peer entries with a new flag and translate it to a
corresponding nl80211 flag in the nl80211 driver.
In addition, correct TDLS related documentation in the wpa_driver_ops
structure.
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Cc: Kalyan C Gaddam <chakkal@iit.edu>
Register for the TDLS discovery response public action frame in nl80211.
Print out a debug message when a Discovery Resp frame is received and
validated.
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Cc: Kalyan C Gaddam <chakkal@iit.edu>
Allow passing high-level TDLS commands and TDLS frames to kernel
via new nl80211 commands.
Propagate TDLS related nl80211 capability flags from kernel and add them
as driver capability flags.
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Cc: Kalyan C Gaddam <chakkal@iit.edu>
Netlink sockets can be shared among all driver instances, saving lots
of sockets, spurious log messages, memory, and CPU usage when using
multiple interfaces in a single process.
This offloads the station polling to driver wrappers, which may offload
it again to the driver. The hostap driver wrapper uses "real" data
frames while nl80211 uses null data frames.
Also add a specific event to indicate that a poll was successful for
future use with the nl80211 driver.
Remove the separate driver_ops functions set_cts_protect(),
set_preamble(), set_short_slot_time(), and set_ht_params(). These
belong into same set of operations as set_ap(), so there is no need
to maintain separate functions that just make the driver wrapper
more complex.
Since these have only been used with driver_nl80211.c, the driver_ops
can be removed immediately instead of maintaining backwards
compatibility period with the old functions.
The AP client isolation parameter is now available through set_ap().
driver_nl80211.c was the only driver wrapper using the set_intra_bss()
call in hostap.git, but some external trees may have used this. Once
those are cleared, the set_infra_bss() driver_ops can be removed
completely. The only remaining use case for it currently is in P2P
GO mode with wpa_supplicant.
"hostapd_cli ess_disassoc (STA addr) (URL)" can now be used to send
an ESS Dissassociation Imminent notification to the STA. This event
is shown in wpa_supplicant ctrl_iface monitors (e.g., wpa_cli):
"WNM: ESS Disassociation Imminent - session_info_url=http://example.com/session/"
Use the SSID filter list passed in the scheduled scan request down to
the kernel driver, so it can use the list to return only the wanted
SSIDs. Some kernel drivers can use this information to offload the
SSID filter to the hardware, helping with reducing the power
consumption.
Signed-off-by: Luciano Coelho <coelho@ti.com>
Currently the P2P Interface name[p2p-%s-%d] is reset when the P2P
Interface name reaches the "IFNAMSIZ" limit. Monitor interface name is
derived from p2p interface name with the addition of few characters
[mon.p2p-%s-%d] and hence Monitor interface name hits IFNAMSIZ limit
before P2P Interface name. Rename the monitor interface name to
mon-%s-%d to reduce the length to same with p2p-%s-%d.
This new flag can be used to change wpa_supplicant behavior in the
default ap_scan=1 mode to move BSS selection into the driver (likely
firmware). This commit is only adding the flag; separate commits
will be used to change the actual connection/roaming behavior.
This adds support for RSN pre-authentication with nl80211 interface and
drivers that handle roaming internally (i.e., wpa_supplicant is not
responsible for requesting scan results that provide the needed
information without these events).
cfg80211 does not currently allow NL80211_CMD_CONNECT when there
is already an association. This can result in wpa_supplicant being
unable to request a connection if the interface is already in
connected state. Work around this by requesting disconnection if
the connect command fails with EALREADY error. This allows
wpa_supplicant to recover from the unexpected state and complete
the connect request on next attempt.
Currently, the following can happen:
1) P2P state machine requests R-O-C
2) user changes their mind and aborts
3) P2P state machine aborts R-O-C
4) driver_nl80211 rejects abort since there
was no notification about the start yet
5) R-O-C period start notification from kernel
6) P2P state machine requests new R-O-C
7) this overlaps with old R-O-C -- iwlwifi driver
can't handle that and returns -EBUSY
8) state machine stops dead in its tracks
The reason is that the abort isn't going through properly. Instead of
tracking whether a R-O-C is active in driver_nl80211, track whether one
was requested to avoid this scenario.
Reported-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This allows drivers to disable CCK rates from Probe Request frames.
For nl80211, this is currently applying only to the supported rates
element(s), but this mechanism could be extended to address TX rate
control masking, too, to lessen need for global rate disabling.
Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Since the kernel can now advertise P2P concurrent support by advertising
interface combinations, we can take advantage of that and automatically
use P2P_CONCURRENT / P2P_MGMT_AND_NON_P2P for drivers that advertise
support.
Keep driver_param=use_p2p_group_interface=1 for anyone not advertising
interface combinations in their drivers yet.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The previous code was trying to figure out which WPA version is
used based on the extra IEs requested for Association Request. That
did not work properly in cases where non-WPA networks are used with
some extra IEs. Fix this by using more robust mechanism for passing
the WPA versions from core wpa_supplicant to the driver_ops
associate().
This allows non-mac80211 drivers to report received Probe Request
frames to user space and Probe Response and Action frames to be sent
from user space when using AP/P2P GO mode.
This allows the driver to use PS buffering of Deauthentication and
Disassociation frames when the STA is in power save sleep. The STA
entry (and PTK) will be removed from the kernel only after the
Deauth/Disassoc has been transmitted (e.g., when the STA wakes up).
A hardcoded two second timeout is used to limit the length of this
window should the driver fail to deliver the frame (e.g., the STA
is out of range and does not wake up). The kernel STA entry is
marked unauthorized during the wait to avoid accepting Data
frames from the STA that we have decided to disconnect.
This behavior is available only with drivers that provide TX status
events for Deauth/Disassoc frames (nl80211 at this point). Other
drivers continue to use the previous behavior where the STA entry
is removed immediately.
This change is a first step in better supporting different driver
architectures for AP mode operations with nl80211. This commit in
itself does not add new functionality, but it makes it easier to add
new AP mode parameters to address needs of drivers that have more of
the MLME/SME in firmware or kernel.
Such using params->wpa_ie to figure out whether the connection is for
WPA/WPA2 is not correct since that buffer is used also to add WPS IE. In
case of WPS, do not add NL80211_ATTR_WPA_VERSIONS to avoid confusing
drivers.
Currently, wpa_driver_nl80211_authenticate() changes the interface type
to station. However, in case of P2P, we need to change the interface
type to P2P_CLI.
Add p2p field to the authentication params, and consider it for choosing
the correct interface type.
Signed-off-by: Eliad Peller <eliad@wizery.com>
Commit 9f51b11395 added support for P2P
interfaces when adding a new interface. However, it didn't handle the
case in which the same interface is being used and its type is being
changed. Add support for this case.
Consequently, when doing "ap_scan_as_station" we now need to save the
actual AP interface type (AP/P2P GO) in order to restore it properly.
For that, change ap_scan_as_station type from int to nl80211_iftype, and
set it to NL80211_IFTYPE_UNSPECIFED when not used.
Signed-off-by: Eliad Peller <eliad@wizery.com>
When driver_nl80211.c has to set the netdev down to change iftype, an
RTM_NEWLINK event is generated. Do not generate
EVENT_INTERFACE_DISABLED event based on that.
When a new interface is created and already has a separate MAC address
assigned by the kernel, then we need to use that address, not just when
we've created a locally administered address.
This fixes use_p2p_group_interface=1 for iwlagn as it already makes
mac80211 assign an address for a second interface since the hardware has
two addresses assigned.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Add support to wpa_supplicant for device-based GTK rekeying. In order to
support that, pass the KEK, KCK, and replay counter to the driver, and
handle rekey events that update the latter.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Send STA flags to kernel when adding a new station. This ensures
stations are added with up to date flags by kernel drivers.
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Implement PMKSA cache operations add, remove, and flush using nl80211
commands NL80211_CMD_{SET,DEL,FLUSH}_PMKSA to support PMKSA caching
with drivers that select the AP and generate the RSN IE internally.
Some of these are required for proper functionality (like
get_seqnum); others may not be needed yet, but including them
allows some extra ifdef/endif blocks to be removed.
.set_rate_sets is not defined for non-hostapd, which prevents
configuring basic_rates when working as P2P GO.
Signed-off-by: Eliad Peller <eliad@wizery.com>
cfg80211 maintains separate BSS table entries for APs if the same
BSSID,SSID pair is seen on multiple channels. wpa_supplicant does
not use frequency as a separate key in the BSS table, so filter out
duplicated entries. Prefer associated BSS entry in such a case in
order to get the correct frequency into the BSS table.
When the SME is in the driver or cfg80211, the automatic selection
of auth_alg is done by leaving out the NL80211_ATTR_AUTH_TYPE
attribute from the NL80211_CMD_CONNECT command.
This should fix EAPOL reauthentication and rekeying timeout issues
with Intel clients when using WMM (e.g., with IEEE 802.11n). These
stations do not seem to be able to handle EAPOL data frames as
non-QoS Data frames after the initial setup.
This adds STA flags to hapd_send_eapol() driver op to allow
driver_nl80211.c to mark the EAPOL frames as QoS Data frame
when injecting it through the monitor interface.
This provides a means for the supplicant to directly request signal
quality metrics from the driver. This is useful, for example for
background scan algorithms that might ask desire this information
out-of-band with CQM events.
Signed-off-by: Paul Stewart <pstew@google.com>
If the driver advertises max_remain_on_chan data, use it instead of
the hardcoded value of 5000. Keep the default at 5000 since that is the
value used by earlier versions of cfg80211/mac80211 and not advertised
in nl80211 for those.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
When authenticating, and the interface type is not already
NL80211_IFTYPE_STATION, we need to call wpa_driver_nl80211_set_mode()
only once. Remove the excessive call.
Signed-off-by: Eliad Peller <eliad@wizery.com>
We can use the P2P interface types to check if the driver supports P2P
and to tell the kernel that a given interface is going to be used for
P2P (when it is created).
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
In order to enable protection mechanisms for different HT opmodes the
driver needs to be aware of the current HT opmode that is calculated by
hostapd. Hence, pass the current opmode to the nl80211 driver via
the bss attribute NL80211_ATTR_BSS_HT_OPMODE.
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Previously, both NULL and ff:ff:ff:ff:ff:ff addr were used in various
places to indicate default/broadcast keys. Make this more consistent
and useful by defining NULL to mean default key (i.e., used both for
unicast and broadcast) and ff:ff:ff:ff:ff:ff to indicate broadcast
key (i.e., used only with broadcast).
When hostapd is removing a virtual BSS interface, the loop here was
incorrectly not updating the iterator during list traversal and
ended up in an infinite loop in some cases.
If the underlying driver supports off-channel TX, it will now be used by
the nl80211 driver wrapper, setting WPA_DRIVER_FLAGS_OFFCHANNEL_TX
accordingly.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
With the new kernel functionality coming to Linux to allow off-channel
TX, we can take advantage of that in the P2P code that currently uses
remain-on-channel. If a driver advertises support for it, it will be
asked to handle off-channel TX by itself.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
The nl80211 driver can report low ACK condition (in fact it reports
complete loss right now only). Use that, along with a config option, to
disconnect stations when the data connection is not working properly,
e.g., due to the STA having went outside the range of the AP. This is
disabled by default and can be enabled with disassoc_low_ack=1 in
hostapd or wpa_supplicant configuration file.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
If a station received unprotected Deauthentication or Disassociation
frame with reason code 6 or 7 from the current AP, there may be a
mismatch in association state between the AP and STA. Verify whether
this is the case by using SA Query procedure. If not response is
received from the AP, deauthenticate.
This implementation is only for user space SME with
driver_nl80211.c.
Previously, pairwise and group cipher suites were configured only
when kernel SME (nl80211 connect API) was used. However, mac80211
needs this information even in the user space SME case for one
thing: to disable HT when TKIP/WEP is used. Add
NL80211_ATTR_CIPHER_SUITES_PAIRWISE to fix this special case with
user space SME. This allows mac80211 to disable HT properly when
the AP is configured with configuration that is not allowed.
This add preliminary code for setting the per-STA RX GTK for
RSN IBSS when nl80211 drivers. For some reason, this does not
seem to fully work, but at least driver_nl80211.c is now aware of
what kind of key is being set and the whatever is missing from
making this key configuration go through should be specific to
nl80211/cfg80211.
When controlling multiple virtual interfaces on the same physical
radio, share the scan results events with sibling interfaces. This
decreases the time it takes to connect many virtual interfaces.
This is currently only supported on Linux with cfg80211-based
drivers when using nl80211 or wext driver interface.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Some drivers are not providing exactly reliable error codes (e.g.,
with WEXT), but others may actually indicate reliable information.
Allow driver wrappers to indicate if that is the case and use
optimizations if so. For now, this improves nl80211 with
NL80211_CMD_CONNECT for a case where connection request fails.
driver_param=use_p2p_group_interface=1 can now be used to test
nl80211-drivers with separate P2P group interface. In other words,
the main interface (e.g., wlan0) is reserved for P2P management
operations and non-P2P connections and a new group interface (e.g.,
p2p-wlan0-0) is created for the P2P group.
This implementation is very minimal, i.e., it only support address
allocation for a single P2P group interface (if the driver does not
handle this internally). In addition, not all functionality has yet
been tested, so for now, this is disabled by default and needs that
special driver_param to enable.
driver.h defines these functions to return 0 on success, not
number of bytes transmitted. Most callers are checking "< 0" for
error condition, but not all. Address this by following the driver
API specification on 0 meaning success.
These are not used by any driver wrapper, i.e., only the four
data queues (BK, BE, VI, VO) are configurable. Better remove these
so that there is no confusion about being able to configure
something additional.
Pass data frames from unknown STAs to hostapd in order to reply with
a Deauthentication or Disassociation frame. This fixes compliance
with IEEE Std 802.11-2007, 11.3.
Furthermore, this does not cause a lot of overhead (at least with
mac80211 drivers) since mac80211 does not pass all data frames (but
at least from unauthenticated and unassociated STAs) to cooked monitor
interfaces.
Tested with rt2800pci on a MIPS board.
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Listen to regulatory event messages from kernel and convert them to
internal driver event notifications indicated that the channel list
may have changed.
The new nl80211 API means we don't need to use monitor interfaces. This
means that the P2P implementation now requires a kernel that has support
for generic management frame (not just Action frame) transmission.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This is backward compatible since older kernels will ignore the extra
attribute and only allow registration for Action frames.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
libnl has a bug, when binding more than two sockets and releasing one,
it will release the wrong address and then try to reuse it, which fails.
Therefore, we need to reimplement the socket address assignment logic
locally for libnl 1.1.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
When passing several authentication algorithms through auth_alg, we
should try all of them when the first one fails. The wext driver goes
through the connect nl80211 command and the retries are then handled by
the kernel. The nl80211 doesn't and we have to handle that from
userspace.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
DEAUTH messages can come from a number of different sources. The one
that's hurting us currently is DEAUTH netlink messages coming to us
from compat-wireless in response to local_state_change DEAUTH messages
we sent as a part of cleaning up state in driver_nl80211's
clear_state_mismatch() function. However, DEAUTH messages can come
from a variety of unwanted sources, including directed denial-of-service
attacks (although MAC verification doesn't place that high a barrier),
so this validation is actually generically useful, I think.
The downside to this method is that without a kernel based approach
"iw dev wlan0 link" no longer works correctly after clear_state_mismatch()
is done. This will be pursued with the kernel folks.
cfg80211/mac80211 seems to be unwilling to change interface mode in
some cases. Make these less likely to cause problems by trying the
changes up to 10 times with 100 msec intervals.
Replace use of rfkill block event with rtnetlink ifdown. This makes
the design more robust since the rfkill event could have been for
another interface while the rtnetlink events are already filtered
based of ifindex. In addition, the new design handles other than
rfkill-triggered ifdown/ifup events, too. rfkill unblocked event
is still needed to try to set the interface back up. If the unblock
was for another interface, ifup will fail and the driver state is
not changed.
Add a new wpa_supplicant state: interface disabled. This can be used
to allow wpa_supplicant to be running with the network interface even
when the driver does not actually allow any radio operations (e.g.,
due to rfkill).
Allow driver_nl80211.c and driver_wext.c to start while rfkill is in
blocked state (i.e., when ifconfig up fails) and process rfkill
events to block/unblock WLAN.
This adds more details into the CTRL-EVENT-DISCONNECTED event to
make it easier to figure out which network was disconnected in some
race conditions and to what could have been the reason for
disconnection. The reason code is currently only available with
the nl80211 driver wrapper.
There is no absolute requirement for separating address allocation
into separate functions, so simplify the driver wrapper interface
to use just if_add and if_remove instead of adding the new
alloc_interface_addr() and release_interface_addr() functions.
if_add() can now indicate if the driver forced a different interface
name or address on the virtual interface.
This removes transmission of some unnecessary Deauthentication
frames in cases where we only need to clear the local state. In
addition, this resolves issues for 802.11r FT-over-DS by allowing
authentication state to be set locally even when no actual
Authentication frame is to be transmitted.
This can be used to test 802.11w by sending a protected or unprotected
deauth/disassoc frame.
hostapd_cli deauth <dst addr> test=<0/1>
hostapd_cli disassoc <dst addr> test=<0/1>
test=0: unprotected
test=1: protected
This is a step in adding FT support with nl80211-based drivers.
driver_nl80211.c is now registering to handle the FT Action frames
and is able to transmit FT Request frame. Received FT Action frames
are not yet indicated as driver events.
This patch allows the nl80211 driver to create its own per-bss context
and pass it to the drv_priv pointer of the hostapd bss state.
With this and the following patch, stations can associate to and switch
between multiple BSS interfaces of a single wiphy.
This obsoletes a few instances of passing ifname to a callback, those
can be removed in a separate patch.
It might also be useful to move more fields from the driver data to the
per-bss data structure in the future.
filter_ssids=1 global configuration parameter can now be used to
enable scan result filtering (with -Dnl80211 only for now) based on
the configured SSIDs. In other words, only the scan results that have
an SSID matching with one of the configured networks are included in the
BSS table. This can be used to reduce memory needs in environments that
have huge number of APs.
wpa_supplicant can now be notified of suspend/resume events, e.g.,
from pm-action scripts. This allows wpa_supplicant to clear information
that may become invalid during a suspend operation.
The kernel side support for this was just added into
wireless-testing.git. This commit adds the driver wrapper code needed
to allow wpa_supplicant to use the new functionality.
Some drivers may need to use a specific ifname for the virtual
interface, so allow them to do this with a new parameter passed
to the alloc_interface_addr() handler.
This may help in debugging why cfg80211 refused the association
command since the scan results should include information about all
pending authentication and association states.
cfg80211 has a limit on pending authentications, so we better clear
the entries that we do not care about to avoid hitting the limit
when roaming between multiple APs.
This allows the driver wrappers to return two sets of IEs, so that
the BSS code can use information from both Beacon and Probe Response
frames if needed. For example, some Cisco APs seem to include more
information in Wireless Provisioning Services IE when it is in the
Beacon frame.
This makes the bridge parameter unnecessary for cases where the interface
is already in a bridge and sysfs is mounted to /sys so that the detection
code works.
For nl80211, the bridge parameter can be used to request the AP
interface to be added to the bridge automatically (brctl may refuse to
do this before hostapd has been started to change the interface mode).
If needed, the bridge interface is also created.
Number of Linux driver wrappers included this more or less identical
function, so lets add a new helper file to be able to share some more
code between the driver wrappers.
Most of this file was already moved into wpa_supplicant/scan.c and
we can remove the file completely by having couple of small helper
functions copied to the remaining users outside core wpa_supplicant
code.
This adds new commands and events for allowing off-channel Action
frame exchanges to be requested. This functionality is not yet used
and is only fully supported by driver_test.c at this point.
driver_nl80211.c has support for the remain-on-channel commands, but
the Action frame TX/RX part is still pending review for the kernel
code and as such, is not yet included here.
This adds placeholder code for allowing the virtual interfaces to be
pre-allocated a MAC address before the interface type is known with
drivers that do not handle interface type changes.
Get more information about scans when updating BSS table information.
This allows the missing-from-scans expiration rule to work properly
when only partial set of channels or SSIDs are being scanned.
There does not seem to be a driver interface for fetching auth_algs
capability, but this may be used by some external application, so
hardcode all auth_algs as supported for now.
This mode allows associated stations to use 4-address frames to allow
layer 2 bridging to be used. At least for the time being, this is only
supported with driver=nl80211.
