Due to the previous commit, when a scan finishes, it is in theory
possible to hit the following sequence:
 1. interface starts being removed
 2. scan is cancelled by driver and cfg80211 is notified
 3. scan done work is scheduled
 4. interface is removed completely, rdev->scan_req is freed,
    event sent to userspace but scan done work remains pending
 5. new scan is requested on another virtual interface
 6. scan done work runs, freeing the still-running scan

To fix this situation, hang on to the scan done message and block
new scans while that is the case, and only send the message from
the work function, regardless of whether the scan_req is already
freed from interface removal. This makes step 5 above impossible
and changes step 6 to be
 5. scan done work runs, sending the scan done message

As this can't work for wext, so we send the message immediately,
but this shouldn't be an issue since we still return -EBUSY.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Add a utility function to get the number of channels supported by
the device, and update the places in the code that need this data.
Signed-off-by: NIlan Peer <ilan.peer@intel.com>
[replace another occurrence in libertas, fix kernel-doc, fix bugs]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

___cfg80211_scan_done() can be called in some cases
(e.g. on NETDEV_DOWN) before the low level driver
notified scan completion (which is indicated by
passing leak=true).

Clearing rdev->scan_req in this case is buggy, as
scan_done_wk might have already being queued/running
(and can't be flushed as it takes rtnl()).

If a new scan will be requested at this stage, the
scan_done_wk will try freeing it (instead of the
previous scan), and this will later result in
a use after free.

Simply remove the "leak" option, and replace it with
a standard WARN_ON.

An example backtrace after such crash:
Unable to handle kernel paging request at virtual address fffffee5
pgd = c0004000
[fffffee5] *pgd=9fdf6821, *pte=00000000, *ppte=00000000
Internal error: Oops: 17 [#1] SMP ARM
PC is at cfg80211_scan_done+0x28/0xc4 [cfg80211]
LR is at __ieee80211_scan_completed+0xe4/0x2dc [mac80211]
[<bf0077b0>] (cfg80211_scan_done+0x28/0xc4 [cfg80211])
[<bf0973d4>] (__ieee80211_scan_completed+0xe4/0x2dc [mac80211])
[<bf0982cc>] (ieee80211_scan_work+0x94/0x4f0 [mac80211])
[<c005fd10>] (process_one_work+0x1b0/0x4a8)
[<c0060404>] (worker_thread+0x138/0x37c)
[<c0066d70>] (kthread+0xa4/0xb0)
Signed-off-by: NEliad Peller <eliad@wizery.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Since rdev->sched_scan_req is dereferenced outside the
lock protecting it, this might be done at the wrong
time, causing crashes. Move the dereference to where
it should be - inside the RTNL locked section.

Cc: stable@vger.kernel.org [3.8+]
Reviewed-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This function is being removed, so remove the reference to it.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

To allow scanning and working with 5 MHz and 10 MHz BSS, extend the
inform bss commands and add wrappers to take 5 and 10 MHz bss into
account.
Signed-off-by: NSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: NMathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>

Should help the next person that tries to understand
the bss refcounting logic.
Signed-off-by: NBen Greear <greearb@candelatech.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Virtually all code paths in cfg80211 already (need to) hold
the RTNL. As such, there's little point in having another
four mutexes for various parts of the code, they just cause
lock ordering issues (and much of the time, the RTNL and a
few of the others need thus be held.)

Simplify all this by getting rid of the extra four mutexes
and just use the RTNL throughout. Only a few code changes
were needed to do this and we can get rid of a work struct
for bonus points.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

The function is only used and needed by the wext code
for scanning, so move it there.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

If a P2P device wdev is removed while it has a scan, then the
scan completion might crash later as it is already freed by
that time. To avoid the crash always check the scan completion
when the P2P device is being removed for some reason. If the
driver already canceled it, don't want and free it, otherwise
warn and leak it to avoid later crashes.

In order to do this, locking needs to be changed away from the
rdev mutex (which can't always be guaranteed). For now, use
the sched_scan_mtx instead, I'll rename it to just scan_mtx in
a later patch.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

In the odd case that while updating information from a beacon,
a BSS was found that is part of a hidden group, we drop the
new information. In this case, however, we leak the IE buffer
from the update, and erroneously update the entry's timestamp
so it will never time out. Fix both these issues.

Cc: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Add new NL80211_CMD_RADAR_DETECT, which starts the Channel
Availability Check (CAC). This command will also notify the
usermode about events (CAC finished, CAC aborted, radar
detected, NOP finished).
Once radar detection has started it should continuously
monitor for radars as long as the channel is active.

This patch enables DFS for AP mode in nl80211/cfg80211.

Based on original patch by Victor Goldenshtein <victorg@ti.com>
Signed-off-by: NSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
[remove WIPHY_FLAG_HAS_RADAR_DETECT again -- my mistake]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

cfg80211_find_vendor_ie() was checking only that the vendor IE would
fit in the remaining IEs buffer.  If a corrupt includes a vendor IE
that is too small, we could potentially overrun the IEs buffer.

Fix this by checking that the vendor IE fits in the reported IE length
field and skip it otherwise.
Reported-by: NJouni Malinen <j@w1.fi>
Signed-off-by: NLuciano Coelho <coelho@ti.com>
[change BUILD_BUG_ON to != 1 (from >= 2)]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

While technically the TSF isn't an IE, it can be
necessary to distinguish between the TSF from a
beacon and a probe response, in particular in
order to know the next DTIM TBTT, as not all APs
are spec compliant wrt. TSF==0 being a DTIM TBTT
and thus the DTIM count needs to be taken into
account as well.

To allow this, move the TSF into the IE struct
so it can be known whence it came.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

There's no way scan BSS IEs can be NULL as even
if the allocation fails the frame is discarded.
Remove some code checking for this and document
that it is always non-NULL.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Currently, cfg80211 will copy beacon IEs from a previously
received hidden SSID beacon to a probe response entry, if
that entry is created after the beacon entry. However, if
it is the other way around, or if the beacon is updated,
such changes aren't propagated.

Fix this by tracking the relation between the probe
response and beacon BSS structs in this case.

In case drivers have private data stored in a BSS struct
and need access to such data from a beacon entry, cfg80211
now provides the hidden_beacon_bss pointer from the probe
response entry to the beacon entry.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This prepares for using the spinlock instead of krefs
which is needed in the next patch to track the refs
of combined BSSes correctly.

Acked-by: Bing Zhao <bzhao@marvell.com> [mwifiex]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Add inline wrappers for the BSS struct krefs
to be able to extend them easily later.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This local variable is only used once, so remove it.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Instead of annotating with a comment, add a lockdep
annotation which also serves as documentation.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

There's no reason for it to require external
locking, move it into the function.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

The comment about allocating the IEs together with
the BSS struct is no longer true, remove it. Also
fix a typo in the same area.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

As Thomas pointed out, cfg80211_get_mesh() is
unused and can be removed.

Cc: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Instead of first checking if a BSS is an MBSS
and then doing the comparisons, inline it all
into the BSS comparison function. This avoids
doing the IE searches twice and is also a lot
less code.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

When trying to find a hidden SSID, the lookup function
is done wrong; the code is trying to combine the two
lookups into one, and as a consequence doesn't always
find the entry at all. To understand this, consider a
case where multiple BSS entries with the same channel
and BSSID exist but have different SSID length. Then
comparing against the probe response SSID length is
bound to cause problems since the hidden one might be
either zeroed out or zero-length.

To fix this we need to do two lookups for the two ways
to hide SSIDs.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Instead of duplicating the rbtree functions, pass
an argument to the compare function. This removes
the code duplication for the two searches.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Now that mac80211 no longer uses this API, remove
it completely. If anyone needs it again, we can
revert this patch of course, but mac80211 was the
only user right now.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

We do a:

	sprintf(buf, " Last beacon: %ums ago",
		elapsed_jiffies_msecs(bss->ts));

elapsed_jiffies_msecs() can return a 10 digit number so "buf" needs to
be 31 characters long.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

When a BSS struct is updated, the IEs are currently
overwritten or freed. This can lead to races if some
other CPU is accessing the BSS struct and using the
IEs concurrently.

Fix this by always allocating the IEs in a new struct
that holds the data and length and protecting access
to this new struct with RCU.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

The cmp_bss() comparator function uses memcmp() to
compare the SSID. This means that cmp_hidden_bss()
needs to similarly return a number bigger than zero
(use 1) instead of -1 when ie1 is bigger than ie2,
which is the case if an ie2 byte is non-zero.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Fix a number of indentation and similar issues.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

There's no need to stop the machine, just leak
the BSS entry if there's an issue with its hold
counter when freeing.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Currently, mac80211 checks the DS params IE if present and
uses it for the (primary) BSS channel, instead of the one
that the frame was received on. This is particularly useful
in the 2.4 GHz band since a frame is often received on one
of the adjacent channels due to overlap.

Move this code to cfg80211 so other drivers also do this.

Additionally, on 5 GHz, in particular with some (possibly)
upcoming changes in 802.11ai and duplicate transmissions
when wider channels are used, something similar happens.
So if present, also use the (primary) channel information
contained in the HT operation IE.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Also add tracing to the API functions that drivers
(and mac80211) can call in cfg80211.
Signed-off-by: NBeni Lev <beni.lev@intel.com>
Reviewed-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Reviewed-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

This will allow adding central tracing like in mac80211.
Signed-off-by: NHila Gonen <hila.gonen@intel.com>
Reviewed-by: NEmmanuel Grumbach <emmanuel.grumbach@intel.com>
Reviewed-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Add an NL80211_SCAN_FLAG_FLUSH flag that causes old bss cache
entries to be flushed on scan completion. This is useful for
collecting guaranteed fresh scan/survey result (e.g. on resume).

For normal scan, flushing only happens on successful completion
of a scan; i.e. it does not happen if the scan is aborted.
For scheduled scan, previous scan results are flushed everytime
when we get new scan results.

This feature is enabled by default. Drivers can disable it by
unsetting the NL80211_FEATURE_SCAN_FLUSH flag.
Signed-off-by: NSam Leffler <sleffler@chromium.org>
Tested-by: NAmitkumar Karwar <akarwar@marvell.com>
Signed-off-by: NAmitkumar Karwar <akarwar@marvell.com>
Signed-off-by: NBing Zhao <bzhao@marvell.com>
[invert polarity of feature flag to account for old kernels]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

bss_release() and __cfg80211_unlink_bss() function definitions
are moved at the begining of the file. They are used in next
patch in this series.
Signed-off-by: NAmitkumar Karwar <akarwar@marvell.com>
Signed-off-by: NBing Zhao <bzhao@marvell.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

checkpatch pointed out an issue, fix it.
Signed-off-by: NHila Gonen <hila.gonen@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

The new P2P Device will have to be able to scan for
P2P search, so move scanning to use struct wireless_dev
instead of struct net_device.
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

Use the new bool function ether_addr_equal to add
some clarity and reduce the likelihood for misuse
of compare_ether_addr for sorting.

I removed a conversion from scan.c/cmp_bss_core
that appears to be a sorting function.

Done via cocci script:

$ cat compare_ether_addr.cocci
@@
expression a,b;
@@
-	!compare_ether_addr(a, b)
+	ether_addr_equal(a, b)

@@
expression a,b;
@@
-	compare_ether_addr(a, b)
+	!ether_addr_equal(a, b)

@@
expression a,b;
@@
-	!ether_addr_equal(a, b) == 0
+	ether_addr_equal(a, b)

@@
expression a,b;
@@
-	!ether_addr_equal(a, b) != 0
+	!ether_addr_equal(a, b)

@@
expression a,b;
@@
-	ether_addr_equal(a, b) == 0
+	!ether_addr_equal(a, b)

@@
expression a,b;
@@
-	ether_addr_equal(a, b) != 0
+	ether_addr_equal(a, b)

@@
expression a,b;
@@
-	!!ether_addr_equal(a, b)
+	ether_addr_equal(a, b)
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>