A lot of management code needs to generate command complete events so it
makes sense to have a helper function for this.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds a get_connections command to the management interface.
With this command userspace can get the current list of connected
devices. Typically this command would only be used once when enumerating
existing adapters. After that the connected and disconnected events are
used to track connections.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch add a new connect failed management event to track failures
in connecting to remote devices. It is particularly useful for security
mode 3 scenarios when we don't have a connected state while pairing but
still need to detect when the connect attempt failed.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds a disconnect command to the managment interface. Using
this command user space is able to force the disconnection of connected
devices. The command maps directly to the Disconnect HCI command.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds connected and disconnected managment events to track the
connection status to remote devices. The events map directly to
successful connection complete and disconnection complete HCI events for
ACL links.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds a management commands to feed the kernel with all stored
link keys as well as remove specific ones or all of them. Once the
load_keys command has been called the kernel takes over link key
replies. A new_key event is also added to inform userspace of newly
created link keys that should be stored permanently.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds the possibility for user space to fully control the
Class of Device value of local adapters. To control the service class
bits each UUID that's added comes with a service class "hint" which acts
as a mask of bits that the UUID needs to have enabled. The
set_service_cache management command is used to make sure we queue up
all UUID changes as user space initializes its drivers and then send a
single HCI_Write_Class_of_Device command when initialization is
complete.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Using the managment interface means that user space doesn't need to do
any HCI command sending at all. This patch moves the remaining
initialization commands from user space to the kernel side. The patch
makes use of the new feature of __hci_request which allows the request
to be dynamically modified while it is ongoing (something that is needed
to react appropriately to the local features and the version of the
adapter).
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
User space should set the page timeout so there's no need to explicitly
set it in the HCI init sequence. Even if user space fails to set it the
controller default value will be used.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
The controller may have link keys in its own memory and these keys could
be used for secure connections. However, since the interface to access
these keys doesn't provide information about the key types (which would
be needed to infer the level of security each key provides) using these
keys is rather useless. Therefore, simply clear the controller side list
in the initialization procedure.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
To support a more dynamic HCI initialization sequence the __hci_request
behavior requires some more changes. Particularly, the init sequence
should be able to have conditionals in it (sending some HCI commands
depending on the outcome of a previous command) instead of being a fixed
list as it is right now.
The reasons for these additional requirements are the moving all
previously user space driven initialization commands to the kernel side
as well as the support the Low Energy controllers.
To fulfull these requirements the init sequence is made the only special
case for multi-command requests and req_last_cmd is renamed to
init_last_cmd. The hci_send_cmd function is changed to update
init_last_cmd as long as the HCI_INIT flag is set.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds the necessary logic to act accordingly when the
HCI_PAIRABLE flag is not set. In that case PIN code replies as well as
Secure Simple Pairing requests without a NoBonding requirement need to
be rejected.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds a debugfs entry to list the UUIDs that have been
registered through the management interface.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds methods to the management interface for userspace to
notify the kernel of which services have been registered for specific
adapters. This information is needed for setting the appropriate Class
of Device value as well as the Extended Inquiry Response value. This
patch doesn't actually implement setting of these values but just
provides the storage of the UUIDs so the needed functionality can be
built on top of it.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch implements a new set_pairable management command to control
the pairable state of local adapters. The state is represented using a
new HCI_PAIRABLE flag in the hci_dev struct.
For backwards compatibility with older user space versions the
HCI_PAIRABLE flag gets automatically set when the existence of an
adapter is reported to user space through legacy methods and the
HCI_MGMT flag is not set.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Several management commands have similar responses but they are not
always sent asynchronously. To enable synchronous sending (from the
managment command handler function) a send_mode_rsp function is added.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds a HCI_MGMT flag to track adapters which are under the
control of the management interface. This is needed to make sure that
new kernels will work with old user space versions. I.e. behaviour which
could break old user space versions (but is needed by the management
interface) should not be exhibited when the HCI_MGMT flag is not set.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
The powered, connectable and discoverable messages all have the same
format. By using a single struct for all of them a lot of code can be
simplified and reused.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds a set_connectable command as well as a corresponding
event to the management interface. It's mainly useful for setting an
adapter as connectable from a non-initialized state as well as setting
an already initialized adapter as non-connectable (mostly useful for
qualification purposes).
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds a set_discoverable command to the management interface
as well as the corresponding event. The command is used to control the
discoverable state of adapters.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds a set_powered command to the management interface
through which the powered state of local adapters can be controlled.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch adds support for the powered event that's used to indicate to
userspace when the powered state of a local adapter changes.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This patch implements automatic initialization of basic information
about newly registered Bluetooth adapters. E.g. the address and features
are always needed so it makes sense for the kernel to automatically
power on adapters and read this information. A new HCI_SETUP flag is
added to track this state.
In order to not consume unnecessary amounts of power if there isn't a
user space available that could switch the adapter back off, a timer is
added to do this automatically as long as no Bluetooth user space seems
to be present. A new HCI_AUTO_OFF flag is added that user space needs to
clear to avoid the automatic power off.
Additionally, the management interface index_added event is moved to the
end of the HCI_SETUP stage so a user space supporting the managment
inteface has all the necessary information available for fetching when
it gets notified of a new adapter. The HCI_DEV_REG event is kept in the
same place as before since existing HCI raw socket based user space
versions depend on seeing the kernels initialization sequence
(hci_init_req) to determine when the adapter is ready for use.
Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Modification of Nick Pelly <npelly@google.com> patch.
With Bluetooth 2.1 ACL packets can be flushable or non-flushable. This commit
makes ACL data packets non-flushable by default on compatible chipsets, and
adds the BT_FLUSHABLE socket option to explicitly request flushable ACL
data packets for a given L2CAP socket. This is useful for A2DP data which can
be safely discarded if it can not be delivered within a short time (while
other ACL data should not be discarded).
Note that making ACL data flushable has no effect unless the automatic flush
timeout for that ACL link is changed from its default of 0 (infinite).
Default packet types (for compatible chipsets):
Frame 34: 13 bytes on wire (104 bits), 13 bytes captured (104 bits)
Bluetooth HCI H4
Bluetooth HCI ACL Packet
.... 0000 0000 0010 = Connection Handle: 0x0002
..00 .... .... .... = PB Flag: First Non-automatically Flushable Packet (0)
00.. .... .... .... = BC Flag: Point-To-Point (0)
Data Total Length: 8
Bluetooth L2CAP Packet
After setting BT_FLUSHABLE
(sock.setsockopt(274 /*SOL_BLUETOOTH*/, 8 /* BT_FLUSHABLE */, 1 /* flush */))
Frame 34: 13 bytes on wire (104 bits), 13 bytes captured (104 bits)
Bluetooth HCI H4
Bluetooth HCI ACL Packet
.... 0000 0000 0010 = Connection Handle: 0x0002
..10 .... .... .... = PB Flag: First Automatically Flushable Packet (2)
00.. .... .... .... = BC Flag: Point-To-Point (0)
Data Total Length: 8
Bluetooth L2CAP Packet
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
If alloc_skb() fails in read_index_list() we'll return -ENOMEM without
releasing 'hci_dev_list_lock'.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
"ap" is the address of sdata->u.ap so it can never be NULL here. Also
we dereferenced it on the previous line. I removed the check.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
mac80211 now supports passing MCS index to radiotap, so update the
comments regarding this
Signed-off-by: Mohammed Shafi Shajakhan <mshajakhan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Since 4-addr frames completely override the source address which will
make it into the converted 802.3 frames, receiving frames for other
4-addr stations will confuse the bridging code.
To be able to handle traffic for all connected devices, the bridge
code will automatically turn on promiscuous mode, which triggers
this problem.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Reported-by: Steve Brown <sbrown@cortland.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This allows users to tune the connection-loss algorithms
to be more or less lenient. In particular, larger
null-func retries helps when using lots of virtual
stations on a loaded network.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This should decrease un-necessary flushes, on/off channel work,
and channel changes in cases where the only scanned channel is
the current operating channel.
* Removes SCAN_OFF_CHANNEL flag, uses SDATA_STATE_OFFCHANNEL
and is-scanning flags instead.
* Add helper method to determine if we are currently configured
for the operating channel.
* Do no blindly go off/on channel in work.c Instead, only call
appropriate on/off code when we really need to change channels.
Always enable offchannel-ps mode when starting work,
and disable it when we are done.
* Consolidate ieee80211_offchannel_stop_station and
ieee80211_offchannel_stop_beaconing, call it
ieee80211_offchannel_stop_vifs instead.
* Accept non-beacon frames when scanning on operating channel.
* Scan state machine optimized to minimize on/off channel
transitions. Also, when going on-channel, go ahead and
re-enable beaconing. We're going to be there for 200ms,
so seems like some useful beaconing could happen.
Always enable offchannel-ps mode when starting software
scan, and disable it when we are done.
* Grab local->mtx earlier in __ieee80211_scan_completed_finish
so that we are protected when calling hw_config(), etc.
* Pass probe-responses up the stack if scanning on local
channel, so that mlme can take a look.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
I can't think of a valid use case for this aside from debugging (which can
also be done with a real monitor interface), and dropping these frames saves
some precious CPU cycles.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
While leaving oper channel, STA informs sleep state to AP to
stop sending data. Till sending ack for the nullfunc, AP
continues to send the data to STA which restarts ps_timer that
is causing unnecessary nullfunc exchange on timer expiry
when the STA was already moved to offchannel. So don't restart ps_timer
on data reception during scan. This issue was identified by
the following warning.
WARNING: at net/mac80211/tx.c:661 invoke_tx_handlers+0xf07/0x1330 [mac80211]
wlan0: Dropped data frame as no usable bitrate found while scanning and
associated. Target station: 00:03:7f:0b:a6:1b on 5 GHz band
Call Trace:
[<ffffffffa0413ba7>] invoke_tx_handlers+0xf07/0x1330 [mac80211]
[<ffffffffa0414056>] ieee80211_tx+0x86/0x2c0 [mac80211]
[<ffffffffa0414345>] ieee80211_xmit+0xb5/0x1d0 [mac80211]
[<ffffffffa04037e0>] ieee80211_dynamic_ps_enable_work+0x0/0xb0 [mac80211]
[<ffffffffa04158cf>] ieee80211_tx_skb+0x4f/0x60 [mac80211]
[<ffffffffa04026e6>] ieee80211_send_nullfunc+0x46/0x60 [mac80211]
[<ffffffffa0403885>] ieee80211_dynamic_ps_enable_work+0xa5/0xb0 [mac80211]
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rajkumar Manoharan <rmanoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
On review of 'zd1211rw: implement beacon fetching and handling
ieee80211_get_buffered_bc()', Christian Lamparter noted that [1]:
Since zd_beacon_done also uploads the next beacon so long in advance,
there could be an equally long race between the outdated state of the
next beacon's DTIM broadcast traffic indicator (802.11-2007 7.3.2.6)
which -in your case- was uploaded almost a beacon interval ago and
the xmit of ieee80211_get_buffered_bc *now*.
The dtim bc/mc bit might be not set, when a mc/bc arrived after the
beacon was uploaded, but before the "beacon done event" from the
hardware. So, dozing stations don't expect the broadcast traffic
and of course, they might miss it completely.
It's probably better to fix this in mac80211 (see the attached hack).
[1] http://marc.info/?l=linux-wireless&m=129435041117256&w=2
CC: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
TKIP countermeasures depend on devices being able to detect Michael
MIC failures on received frames and for stations to report errors to
the AP. In order to test that behavior, it is useful to be able to
send out TKIP frames with incorrect Michael MIC. This testing behavior
has minimal effect on the TX path, so it can be added to mac80211 for
convenient use.
The interface for using this functionality is a file in mac80211
netdev debugfs (tkip_mic_test). Writing a MAC address to the file
makes mac80211 generate a dummy data frame that will be sent out using
invalid Michael MIC value. In AP mode, the address needs to be for one
of the associated stations or ff:ff:ff:ff:ff:ff to use a broadcast
frame. In station mode, the address can be anything, e.g., the current
BSSID. It should be noted that this functionality works correctly only
when associated and using TKIP.
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The TKIP implementation was originally prepared to be a bit more
flexible in the way Michael MIC TX/RX keys are configured. However, we
are now taking care of the TX/RX MIC key swapping in user space, so
this code will not be needed. Similarly, there were some remaining WPA
testing code that won't be used in their current form. Remove the
unneeded extra complexity.
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>
There's no point in disallowing scanning for a
GO interface when it's not beaconing yet.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Beacons from external BSSes are required for updating overlapping BSS
info (i.e. ERP protection). Pass them up unconditionally.
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When operating in AP mode the wl1271 hardware filters out null-data
packets as well as management packets. This makes it impossible for
mac80211 to monitor the PS mode by using the PM bit of incoming frames.
Implement a HW flag to indicate that mac80211 should ignore the PM bit.
In addition, expose ieee80211_sta_ps_transition() to make low-level
drivers capable of controlling PS-mode.
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When rate-control is performed in HW, we cannot calculate frame
duration as we do not have the skb transmission rate in SW.
ieee80211_tx_h_calculate_duration() should only be called when
ieee80211_tx_h_rate_ctrl() has been called before to initialize data
in skb->cb. This doesn't happen for drivers with HW rate-control.
Fixes the following warning when operating in AP-mode
in a driver with HW rate-control.
WARNING: at net/mac80211/tx.c:57 ieee80211_duration+0x54/0x1d8 [mac80211]()
Modules linked in: wl1271_sdio wl1271 firmware_class crc7 mac80211 cfg80211
[<c0046090>] (unwind_backtrace+0x0/0x124) from [<c0064c10>] (warn_slowpath_common+0x4c/0x64)
[<c0064c10>] (warn_slowpath_common+0x4c/0x64) from [<c0064c40>] (warn_slowpath_null+0x18/0x1c)
[<c0064c40>] (warn_slowpath_null+0x18/0x1c) from [<bf040e34>] (ieee80211_duration+0x54/0x1d8 [mac80211])
[<bf040e34>] (ieee80211_duration+0x54/0x1d8 [mac80211]) from [<bf04200c>] (invoke_tx_handlers+0xfa0/0x1088 [mac80211])
[<bf04200c>] (invoke_tx_handlers+0xfa0/0x1088 [mac80211]) from [<bf042178>] (ieee80211_tx+0x84/0x248 [mac80211])
[<bf042178>] (ieee80211_tx+0x84/0x248 [mac80211]) from [<bf042f44>] (ieee80211_tx_pending+0x12c/0x278 [mac80211])
[<bf042f44>] (ieee80211_tx_pending+0x12c/0x278 [mac80211]) from [<c0069a9c>] (tasklet_action+0x68/0xbc)
[<c0069a9c>] (tasklet_action+0x68/0xbc) from [<c006a044>] (__do_softirq+0x84/0x114)
[<c006a044>] (__do_softirq+0x84/0x114) from [<c006a1b8>] (do_softirq+0x48/0x54)
[<c006a1b8>] (do_softirq+0x48/0x54) from [<c006a4f8>] (local_bh_enable+0x98/0xcc)
[<c006a4f8>] (local_bh_enable+0x98/0xcc) from [<bf074e60>] (wl1271_rx+0x2e8/0x3a4 [wl1271])
[<bf074e60>] (wl1271_rx+0x2e8/0x3a4 [wl1271]) from [<bf071ae4>] (wl1271_irq_work+0x230/0x310 [wl1271])
[<bf071ae4>] (wl1271_irq_work+0x230/0x310 [wl1271]) from [<c0076864>] (process_one_work+0x208/0x350)
[<c0076864>] (process_one_work+0x208/0x350) from [<c0076e14>] (worker_thread+0x1cc/0x300)
[<c0076e14>] (worker_thread+0x1cc/0x300) from [<c007bb88>] (kthread+0x84/0x8c)
[<c007bb88>] (kthread+0x84/0x8c) from [<c0041494>] (kernel_thread_exit+0x0/0x8)
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
When a vif goes away, it could cause the super-chan
to be recalculated differently, so do that calculation
on iface removal.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Currently cfg80211 only configures the PSM state to the driver upon creation
of a new virtual interface, but not after interface type change. The mac80211
on the other hand reinitializes its sdata structure every time the interface
type is changed, losing the PSM configuration.
Hence, if the interface type is changed to, say, ad-hoc and then back to
managed, "iw wlan0 get power_save" will claim that PSM is enabled, when in
fact on mac80211 level it is not.
Fix this in cfg80211 by configuring the PSM state to the driver each time
the interface is brought up instead of just when the interface is created.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
I have a netgear WNDR3700 that appears to have an off-by-four
bug in how it fills out the hti->control_chan (I configure the
AP to channel 11, it reports 15 as control_chan).
Poke a message into the kernel logs to give users a
clue as to why they are not getting the expected
channel-type or rate.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
If we cannot set the channel type, set the channel back to the
original.
Don't update the driver hardware if nothing actually changed.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This patch fixes a minor issue that two connection responses will be sent
for one L2CAP connection request. If the L2CAP connection request is first
blocked due to security reason and responded with reason "security block",
the state of the connection remains BT_CONNECT2. If a pairing procedure
completes successfully before the ACL connection is down, local host will
send another connection complete response. See the following packets
captured by hcidump.
2010-12-07 22:21:24.928096 < ACL data: handle 12 flags 0x00 dlen 16
0000: 0c 00 01 00 03 19 08 00 41 00 53 00 03 00 00 00 ........A.S.....
... ...
2010-12-07 22:21:35.791747 > HCI Event: Auth Complete (0x06) plen 3
status 0x00 handle 12
... ...
2010-12-07 22:21:35.872372 > ACL data: handle 12 flags 0x02 dlen 16
L2CAP(s): Connect rsp: dcid 0x0054 scid 0x0040 result 0 status 0
Connection successful
Signed-off-by: Liang Bao <tim.bao@gmail.com>
Acked-by: Ville Tervo <ville.tervo@nokia.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
PS should not be enabled if an infra AP vif exists in
the interface list. So while recalculating PS,
AP vif type should be taken into account.
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rajkumar Manoharan <rmanoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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>
