On DragonFly BSD, wired IEEE 802.1X fails with this message:
ioctl[SIOC{ADD/DEL}MULTI]: Invalid argument
This patch solves this issue.
I have tested with these:
OS : DragonFly BSD 2.4.0
EAP : EAP-TLS
Switch : Cisco Catalyst 2950
This reverts commit 5aa9cb5cca.
The nested key attribute is using different attribute values
(NL80211_KEY_* vs. NL80211_ATTR_KEY_*), so cannot share the same routine
for these purposes..
Current wpa_supplicant has a bug with WEP keys, it adds a zero-length
sequence counter field to netlink which the kernel doesn't accept.
Additionally, the kernel API slightly changed to accept keys only when
connected, so we need to send it the keys after that. For that to work
with shared key authentication, we also include the default WEP TX key
in the authentication command.
To upload the keys properly _after_ associating, add a new flag
WPA_DRIVER_FLAGS_SET_KEYS_AFTER_ASSOC_DONE indicating that the driver
needs the keys at that point and not earlier.
Commit 0b55b934ee broke this by not
initializing drv->ap = 1 in hostapd case since the mode updating
code ended up unlinking the socket file. Setting drv->ap = 1
removes the mode change and as such, unlinking of the socket file.
It is simpler to just build in all the test driver code regardless
of whether this is for hostapd or wpa_supplicant (which will eventually
get AP mode support with driver_test, too).
This is an initial step in adding support for the new connect command.
For now, we just add the capability query. The actual use of the new
command will be added separately.
This is a patch for OpenBSD wired IEEE 802.1X. This is only for wired,
not wireless, because OpenBSD uses wpa_supplicant only on wired now.
http://www.openbsd.org/cgi-bin/cvsweb/ports/security/wpa_supplicant/
I have tested with these.
OS : OpenBSD 4.5
EAP : EAP-TLS
Switch : CentreCOM 8724SL
Previously, both the command replies and unsolicited events were
received from the same socket. This could cause problems if an event
message is received between a command and the response to that command.
Using two sockets avoids this issue.
On NetBSD 5.0, when I use wired 802.1X, "Invalid argument" occurs
on SIOCADDMULTI ioctl and 802.1X fails.
I tried FreeBSD code, but "Address family not supported by protocol family"
occurs on SIOCADDMULTI ioctl and 802.1X fails, too.
This patch solves this issue.
I have tested with these:
OS : NetBSD 5.0
EAP : EAP-MD5
Switch : CentreCOM 8724SL
This is a (hopefully) temporary workaround to allow the same source code
tree to be used for building hostapd and wpa_supplicant without having
to manually force recompilation of some files. Currently, some of the
driver wrapper files need to be built separately for hostapd and
wpa_supplicant (#ifdef's in the files based on AP functionality).
This is somewhat racy as far as parallel make execution is concerned,
i.e., it may be necessary to run "make -j#" twice (plain "make" works
fine. Since this is supposed to be a temporary workaround, there is not
much point in trying to fix this with any more complex make processing.
Instead of having all driver stuff collected across wpa_supplicant
and hostapd, create a common snippet that they both include and
that handles the build configuration.
Current wpa_supplicant has a bug with WEP keys, it adds a zero-length
sequence counter field to netlink which the kernel doesn't accept.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
hostapd currently tries to encrypt all auth frames,
except for "OPEN" and "SHARED with transaction 3".
This means that it will send an encrypted "unknown
auth algorithm" reply for all other algorithsm. Fix
this by changing the logic to only encrypt shared
key auth frames with transaction 3.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Change existing CONFIG_LIBNL20 compatibility code in
driver_nl80211.c to be used by both wpa_supplicant
and hostapd, but take care of nl_handle too now.
Propagate CONFIG_LIBNL20 out of .config file and onto
CFLAGS in the Makefile.
Use libnl-gen now too.
Signed-off-by: Jon Loeliger <jdl@bigfootnetworks.com>
---
This removes need for local configuration to ignore *.o and *~
and allows the src/*/.gitignore files to be removed (subdirectories
will inherit the rules from the root .gitignore).
The driver wrappers should not need to include wps_hostapd.h, so let's
make this easier by introducing a driver callback for reporting Probe
Request frames.
Old way does not work with all drivers on NetBSD and FreeBSD are
also using this so should be a safe change. [Bug 312]
Signed-off-by: Roy Marples <roy@marples.name>
Add generic functions to get/set 80211 vars, set 80211 params and
get/sid ssid.
Change NetBSD defines to match the ioctl used for portability.
Check size we're copying into instead of assuming IFNAMSIZ.
Signed-off-by: Roy Marples <roy@marples.name>
If hostapd segfaults, or is killed with -9, or the interface already exists,
when the interface is created, it will fail.
Configuration file: /tmp/hostapd/hostapd.conf
Failed to create interface mon.wlan0_0.
Using interface wlan0_0 with hwaddr 00:13:01:01:08:0a and ssid 'IG_0405_LAN'
Failed to set beacon head/tail or DTIM period
Failed to create interface wlan0_1.
Try to remove the interface and re-create it before aborting.
To ensure the supplicant starts and ends with a clean slate (keys are
already cleaned up at init and deinit time), force a null BSSID and
bogus SSID to ensure the driver isn't connected to anything.
Signed-off-by: Dan Williams <dcbw@redhat.com>
4853d5ac84 had a small bug in the order
of these function calls in _wext_deauthenticate() (_disassociate()
did have the correct order). The deauthentication frame is supposed
to go out (if driver supports that) before we disconnect more
forcefully.
Otherwise the driver might interpret the request as a request to
create/join a new adhoc network with the bogus SSID.
Signed-off-by: Dan Williams <dcbw@redhat.com>
The attached patch will replace get_scan_results with get_scan_results2.
This is a preparation for WPS on BSD.
And I erased "wpa_scan_result_compar". Because scan result
sorting will be done with "wpa_scan_result_compar" on
"scan_helpers.c".
I have done below tests on NetBSD with an atheros card.
- WPA2-PSK(CCMP)
- WPA-PSK(TKIP)
- PEAP(MSCHAPv2)
- EAP-TLS
- EAP-TTLS(MSCHAPv2)
This adds a cleaner mechanism for protecting against unauthorized
data frames than the previously used drop_unencrypted mechanism
(which is not even available with nl80211 and had to use a WEXT
ioctl.
The old drop_unencrypted code is left in for now as the final
surviving WEXT use in driver_nl80211.c. However, it can be removed
from the build by defining NO_WEXT. It may also be removed
eventually when most users are expected to be using recent enough
kernel version.
For now, the old code using NL80211_ATTR_STA_FLAGS is left in for
backwards compatibility with older kernel versions. It may be removed
eventually when most users are expected to be running with new
enough kernel version.
Attached is a patch for the RoboSwitch driver in trunk. It is a
general revision of the source code.
Changes:
- Improved IEEE 802.1X conformance ([1])
- Better conformity to Broadcom specifications
- Fixed compatibility with different chipset revisions
It is worth noting that performance may drop a little using the new
driver. This can be overcome by using "multicast_only=1" as a
parameter. In that case only packets to the PAE group address are
regarded, as the previous revision of the driver did. A more detailed
description of the parameter and it's consequences is available at [2]
(summary: use "multicast_only=1" whenever possible).
[1] http://lists.shmoo.com/pipermail/hostap/2009-February/019398.html
[2] http://forum.openwrt.org/viewtopic.php?id=19873
None of the driver wrappers user this. hostapd-controlled broadcast SSID
hiding can only be used with drivers that use hostapd for handling
Beacon and Probe Request/Response frames.
None of the driver wrappers use this. Only the drivers that use hostapd
for Beacon and Probe Request/Response handling can now use IEEE 802.11d
properly.
These driver wrappers use UNIX domain sockets and as such, won't be
built with Microsoft compiler. Consequently, use of C99-style designated
initializers can be used to make these files easier to maintain. Only
driver_ndis.c needs to support the old C89-style due to Microsoft
compiler not supporting newer C standard.
This was not really supported by any of the included driver wrappers. If
this functionality is desired in the future, this (or something similar)
can be added with the changes needed into a driver wrapper to use the
mechanism.
This simplifies driver wrapper operations and removes last direct
struct hostapd_data dereferences from driver_nl80211.c. In addition,
some of the TX callbacks are now fixed for secondary BSSes.
This fixes deauth/disassoc frames in secondary BSSes when using
multi-BSSID. In addition, it reduces need to dereference
struct hostapd_data inside driver wrappers.
NO_WEXT can be defined to disable all remaining WEXT uses from
driver_nl80211.c. This breaks some functionality, so the code is still
in use by default. Anyway, the new #ifdef blocks make it easy to search
for areas that need to be converted to nl80211.
Instead of adding a new driver_ops for fetching neighbor BSS data (that
nl80211 driver interface had to scan during initialization), share the
same scan operations that wpa_supplicant is using. This gets rid of
duplicated scan code in driver_nl80211.c (and better yet, removes large
part of old WEXT code).
hostapd interface initialization is now completed in a callback, if
needed, i.e., he_features channel/hw_mode selection can use as much time
as needed. This can also help with radar detection in the future.
hostapd ended up with unregistered send_mlme() in commit
9f324b61ba. Fix this by registering the
handler both for wpa_supplicant-AP and hostapd use. [Bug 310]
Use a parameter structure to pass in information that can be more easily
extended in the future. Include some of the parameters that were
previously read directly from hapd->conf in order to reduce need for
including hostapd/config.h into driver wrappers.
This was not documented properly and was not really used nor would it be
suitable to be used in generic way as it was implemented. It is better
to just remove the parameter since there does not seem to be any
reasonable use for it.
nl80211 interface has a trivial bug that prevents it to work correctly
with channel 14. Channel frequency is erroneously 2848 instead of 2484.
To correct it just apply this patch. [Bug 308]
This merges the driver wrapper implementations to use the same
implementation both for hostapd and wpa_supplicant operations to avoid
code duplication.
This commit merges the driver_ops structures and implementations from
hostapd/driver*.[ch] into src/drivers. This is only an initial step and
there is room for number of cleanups to share code between the hostapd
and wpa_supplicant parts of the wrappers to avoid unnecessary source
code duplication.
Need to set WEP keys before requesting authentication in order to get
Shared Key authentication working. Previously, the WEP keys were not set
at all when using SME in wpa_supplicant.
mac80211 does not use this type of Michael MIC event, so this is not
really used and proper Michael MIC failure processing will be added
using an nl80211 event once that gets added into wireless-testing.git.
It looks like both new nl80211 operations (scan and auth/assoc) end up
being added in Linux 2.6.30, so we do not need to maintain the backwards
compatibility code in wpa_supplicant.
A new network block parameter, scan_freq, can be used to specify subset
of frequencies to scan. This can speed up scanning process considerably
if it is known that only a small subset of channels is actually used in
the network. A union of configured frequencies for all enabled network
blocks is used in scan requests.
Currently, only driver_nl80211.c has support for this functionality.
For example, following parameter marks 2.4 GHz channels 1, 6, 11 to be
scanned: scan_freq=2412 2437 2462
This version is adding the configuration option (mode=2) for this and
driver capability reporting to figure out whether AP mode can be used.
However, this does not actually implement any real functionality yet.
Need to set drv->ifindex before calling set_mode(). In addition, set the
mode before setting the interface up to avoid having to set it down
again.
Add more useful error message on mode changes.
All these driver handlers can be implemented in associate() handler
which gets all the needed information in the parameters structure. The
old functions that provided only a single parameter will be removed
eventually to clean up the driver_ops structure, so driver wrappers
should start using the newer mechanism.
This can be used, e.g., with mac80211-based Linux drivers with
nl80211. This allows over-the-air FT protocol to be used (IEEE
802.11r).
Since the nl80211 interface needed for this is very recent (added
today into wireless-testing.git), driver_nl80211.c has backwards
compatibility code that uses WEXT for association if the kernel does
not support the new commands. This compatibility code can be
disabled by defining NO_WEXT_COMPAT. That code will also be removed
at some point to clean up driver_nl80211.c.
This adds first part of FT resource request as part of Reassocition
Request frame (i.e., FT Protocol, not FT Resource Request Protocol).
wpa_supplicant can generate a test resource request when driver_test.c
is used with internal MLME code and hostapd can verify the FTIE MIC
properly with the included RIC Request.
The actual RIC Request IEs are not processed yet and hostapd does not
yet reply with RIC Response (nor would wpa_supplicant be able to
validate the FTIE MIC for a frame with RIC Response).
This is just there very first step on being able to do something with
wireless LAN on Vista. There is some example code for requesting a scan,
but it does not work in its current form. Anyway, this adds a wpa_printf
noting that Native 802.11 drivers are not yet supported.
This is done with wired interfaces to fix IEEE 802.1X authentication
when the authenticator uses the group address (which should be happening
with wired Ethernet authentication).
This allows wpa_supplicant to complete wired authentication successfully
on Vista with a NDIS 6 driver, but the change is likely needed for
Windows XP, too.
Do not use just the driver name for this since driver_ndis.c supports
both wired and wireless NDIS drivers and needs to indicate the driver
type after initialization.
These flags are used to mark which values (level, noise, qual) are
invalid (not available from the driver) and whether level is using dBm.
D-Bus interface will now only report the values that were available.
This does not actually send out separate scan requests for each SSID,
but the debug output can be used to test scan2() functionality with
multiple SSIDs.
This can be used to provide support for scanning multiple SSIDs at a
time to optimize scan_ssid=1 operations. In addition, Probe Request IEs
will be available to scan2() (e.g., for WPS PBC scanning).
For example, -Dnl80211,wext could be used to automatically select
between nl80211 and wext. The first driver wrapper that is able to
initialize the interface will be used.
This workaround was needed with some drivers that used WEXT, but there
is no known nl80211-enabled driver that would need this, so lets get rid
of the extra delay.
The driver wrappers can now inform wpa_supplicant how many SSIDs can
be used in a single scan request (i.e., send multiple Probe Requests
per channel). This value is not yet used, but it can eventually be used
to allow a new scan command to specify multiple SSIDs to speed up
scan_ssid=1 operations. In addition, a warning could be printed if
scan_ssid=1 is used with a driver that does not support it
(max_scan_ssids=0).
Some drivers (for example ipw2100) do not report signal level but only
signal quality. wpa_supplicant already uses the signal quality if no
level is reported and all other comparision parameters are equal to sort
the scan results. However, if two APs have different max rates and the
signal level does not differ much wpa_supplicant chooses the AP with the
higher max rate.
In case of ipw2100 no signal level is reported and thus wpa_supplicant
always takes the AP with higher max rate even if its signal quality is
really low. For example if AP1 (max rate 11Mb/s, 80% signal quality) and
AP2 (max rate 54 Mb/s, 20% signal quality) are found by a scan
wpa_supplicant would choose AP2.
Hence, if no signal level is reported depend on the signal quality if
max rate should be compared. A quality difference of 10% is considered
acceptable in favor of the higher max rate.
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Really disassociate when tearing stuff down; drivers may sometimes
(legally) keep trying to reassociate unless the BSSID is unlocked. If
the SSID is unlocked too, under WEXT drivers are able to pick an SSID to
associate, so kill that behavior by setting a bogus SSID. Unfortunately
WEXT doesn't provide an easy method to say "stop whatever doing and just
idle".
Signed-off-by: Dan Williams <dcbw@redhat.com>
The madwifi driver has interface to set probe request ie.
Attached patch will enable the functionality.
I could see probe request includes WSC IE with this patch.
We can now handle up to 65535 byte result buffer which is the maximum
due to WEXT using 16-bit length field. Previously, this was limited to
32768 bytes in practice even through we tried with 65536 and 131072
buffers which we just truncated into 0 in the 16-bit variable.
This more or less doubles the number of BSSes we can received from scan
results.
I am terribly sorry, but because of a lack of testing equipment the
patch was submitted not properly tested.
Because the chipset documentation is not publicly available all
behaviour has to be found out by experimentation. The other day, I
made some incorrect assumptions based on my findings.
I do believe the attached patch does support the whole RoboSwitch line
(5325, 5350, 5352, 5365 and others). It is a drop-in substitution for
my previous submission.
The RoboSwitch driver of wpa_supplicant had one shortcoming: not
supporting the 5365 series. I believe the patch attached fixes this
problem.
Furthermore it contains a small readability rewrite. It basically is an
explicit loop-rollout so that the wpa_driver_roboswitch_leave style
matches that of wpa_driver_roboswitch_join.
This commit adds a new build option, CONFIG_IBSS_RSN=y, that can be used
to enable RSN support for IBSS. This links in RSN Authenticator code
from hostapd and adds code for managing per-peer information for IBSS. A
new wpa_cli command or driver event can be used to request RSN
authentication with an IBSS peer. New RSN Authenticator and Supplicant
will be allocated for each peer.
The basic state machine setup code is included in this commit, but the
state machines are not properly started yet. In addition, some of the
callback functions are not yet complete.
This is needed for airo driver to work correctly and no other driver
seems to care, so the change is safe to make. This has been in number of
distro releases for a long time and no issues have been reported.
The new INTERFACE_LIST global control interface command can be used to
request a list of all available network interfaces that could be used
with the enabled driver wrappers. This could be used to enable
interfaces automatically by external programs (e.g., wpa_gui).
Driver wrappers can now register global_init() and global_deinit()
driver_ops handlers to get a global data structure that can be shared
for all interfaces. This allows driver wrappers to initialize some
functionality (e.g., interface monitoring) before any interfaces have
been initialized.
driver_test can now be used either over UNIX domain socket or UDP
socket. This makes it possible to run the test over network and makes it
easier to port driver_test to Windows.
hostapd configuration: test_socket=UDP:<listen port>
wpa_supplicant configuration: driver_param=test_udp=<dst IP addr>:<port>
This adds support for setting of a regulatory domain to wpa_supplicant
drivers. It also adds regulatory domain setting for the nl80211 driver.
We expect an ISO / IEC 3166 alpha2 in the wpa configuration file as a
global.
Fragment WPS IE if needed to fit into the IE length limits in hostapd
and Reassemble WPS IE data from multiple IEs in wpa_supplicant.
In addition, moved WPS code from events.c into wps_supplicant.c to clean
up module interfaces.
This adds WPS support for both hostapd and wpa_supplicant. Both programs
can be configured to act as WPS Enrollee and Registrar. Both PBC and PIN
methods are supported.
Currently, hostapd has more complete configuration option for WPS
parameters and wpa_supplicant configuration style will likely change in
the future. External Registrars are not yet supported in hostapd or
wpa_supplicant. While wpa_supplicant has initial support for acting as
an Registrar to configure an AP, this is still using number of hardcoded
parameters which will need to be made configurable for proper operation.
Find attached the patch that creates a new driver: roboswitch. This
driver adds support for wired authentication with a Broadcom
RoboSwitch chipset. For example it is now possible to do wired
authentication with a Linksys WRT54G router running OpenWRT.
LIMITATIONS
- At the moment the driver does not support the BCM5365 series (though
adding it requires just some register tweaks).
- The driver is also limited to Linux (this is a far more technical
restriction).
- In order to compile against a 2.4 series you need to edit
include/linux/mii.h and change all references to "u16" in "__u16". I
have submitted a patch upstream that will fix this in a future version
of the 2.4 kernel. [These modifications (and more) are now included in
the kernel source and can be found in versions 2.4.37-rc2 and up.]
USAGE
- Usage is similar to the wired driver. Choose the interfacename of
the vlan that contains your desired authentication port on the router.
This name must be formatted as <interface>.<vlan>, which is the
default on all systems I know.
Remove the old code from driver_wext.c since the private ioctl interface is
never going to be used with mac80211. driver_nl80211.c has an
implementation than can be used with mac80211 (with two external patches to
enable userspace MLME configuration are still required, though).
A driver was found to remove SSID IE from NDIS_WLAN_BSSID_EX IEs, but the
correct SSID is included in NDIS_802_11_SSID structure inside the BSSID
data. If this is seen in scan results, create a matching SSID IE and add it
to the end of IEs to fix scan result parsing.
A bug just got reported as a result of this for mac80211 drivers.
https://bugzilla.redhat.com/show_bug.cgi?id=459399
The basic problem is that since taking the device down clears the keys
from the driver on many mac80211-based cards, and since the mode gets
set _after_ the keys have been set in the driver, the keys get cleared
on a mode switch and the resulting association is wrong. The report is
about ad-hoc mode specifically, but this could happen when switching
from adhoc back to managed mode.
If IWEVGENIE or custom event wpa_ie/rsn_ie is received in scan with empty
buffer, the previous version ended up calling realloc(NULL, 0) which seems
to return a non-NULL value in some cases. When this return value is passed
again into realloc with realloc(ptr, 0), the returned value could be NULL.
If the ptr is then freed (os_free(data.ie) in SIOCGIWAP handling), glibc
may crash due to invalid pointer being freed (or double-freed?). The
non-NULL realloc(NULL, 0) return value from glibc looks a bit odd behavior,
but anyway, better avoid this case completely and just skip the IE events
that have an empty buffer.
This issue should not show up with drivers that produce proper scan results
since the IEs will always include the two-octet header. However, it seems
to be possible to see this when using 64-bit kernel and 32-bit userspace
with incorrect compat-ioctl processing.
These functions are based on the hostapd implementation and complete
the userspace MLME code in wpa_supplicant (though, mac80211 will still need
couple of pending patches to be integrated in order to get userspace client
MLME working again).
This adds some parts needed to use usermode MLME with the current mac80211
(plus a patch to add a new cfg80211 command; not yet submitted to
wireless-testing). This version creates a monitor interface for management
frames and is able to send Probe Request frames during scan. However, it
looks like management frame reception is not yet working properly. In
addition, mlme_{add,remove}_sta() handlers are still missing.
Network device ifindex will change when the interface is re-inserted.
driver_nl80211.c will need to accept netlink events from "unknown" (based
on ifindex) interfaces when a previously used card was removed earlier. If
the previously removed interface is added back, the driver_wext data need
to be updated to match with the new ifindex value. In addition, the initial
setup tasks for the card (set interface up, update ifindex, set mode, etc.)
from wpa_driver_nl80211_init() need to be run again.
This is the changes from commit 3fbda8f943
(driver_wext.c) ported for driver_nl80211.c.
Network device ifindex will change when the interface is re-inserted.
driver_wext.c will need to accept netlink events from "unknown" (based on
ifindex) interfaces when a previously used card was removed earlier. If the
previously removed interface is added back, the driver_wext data need to be
updated to match with the new ifindex value. In addition, the initial setup
tasks for the card (set interface up, update ifindex, set mode, etc.) from
wpa_driver_wext_init() need to be run again.
When scan results got moved from wpa_scan_result -> wpa_scan_res, the
'maxrate' member was dropped from wpa_scan_res. The D-Bus interface
used 'maxrate', which was replaced with wpa_scan_get_max_rate().
Unfortunately, wpa_scan_get_max_rate() returns 802.11 rate values
directly from the IE, where 'maxrate' was the rate in bits/second. The
supplicant internally fakes an IE for wpa_scan_res from the value of
wpa_scan_result->maxrate, but interprets ->maxrate as an 802.11 rate
index.
As a side-effect, this fixes a soft-break of the D-Bus control API since
the wpa_scan_res change was introduced.
Just in case, do not use the not-yet-approved WEXT changes even if someone
where to build wpa_supplicant with IEEE 802.11w support unless this new
macro has been defined explicitly.
Added configuration of MFP related parameters with WEXT. The changes to
linux/wireless.h have not yet been applied to the Linux kernel tree, so the
code using them is still open to changes and is ifdef'ed out if
CONFIG_IEEE80211W is not set.
Add the support for the Linux wireless drivers which want to do
4-way handshake and need to know the PSK before the handshake.
Signed-off-by: Masakazu Mokuno <mokuno@sm.sony.co.jp>
driver_nl80211.c is based on driver_wext.c and it is still using Linux
wireless extensions for many functions. Over time, the new driver interface
code should be modified to use nl80211/cfg80211 for everything.
Don't cast pointers to int in definitions of PRISM2_HOSTAPD_RID_HDR_LEN
and PRISM2_HOSTAPD_GENERIC_ELEMENT_HDR_LEN. Use size_t instead. That's
actually what the code needs.
Since mac80211 requires that the device be !IFF_UP to change the mode
(and I think the old prism54 fullmac driver does too), do that. This
shouldn't harm fullmac devices since they can handle mode switches on
the fly and usually don't care about up/down that much.
mac80211 sends _both_ channel and frequency in it's scan results, with
frequency first and channel second (it's since been fixed to send
channel first and frequency second to work around this issue). This
results in wpa_supplicant getting the right value when the frequency
comes, but overwriting the value with '0' when the channel comes because
wpa_supplicant can't handle 5GHz channel numbers. So if a valid
previous SIOCGIWFREQ event came in, don't try to overwrite it.
