+/**
+ * struct ieee80211_ops - callbacks from mac80211 to the driver
+ *
+ * This structure contains various callbacks that the driver may
+ * handle or, in some cases, must handle, for example to configure
+ * the hardware to a new channel or to transmit a frame.
+ *
+ * @tx: Handler that 802.11 module calls for each transmitted frame.
+ * skb contains the buffer starting from the IEEE 802.11 header.
+ * The low-level driver should send the frame out based on
+ * configuration in the TX control data. Must be implemented and
+ * atomic.
+ *
+ * @start: Called before the first netdevice attached to the hardware
+ * is enabled. This should turn on the hardware and must turn on
+ * frame reception (for possibly enabled monitor interfaces.)
+ * Returns negative error codes, these may be seen in userspace,
+ * or zero.
+ * When the device is started it should not have a MAC address
+ * to avoid acknowledging frames before a non-monitor device
+ * is added.
+ * Must be implemented.
+ *
+ * @stop: Called after last netdevice attached to the hardware
+ * is disabled. This should turn off the hardware (at least
+ * it must turn off frame reception.)
+ * May be called right after add_interface if that rejects
+ * an interface.
+ * Must be implemented.
+ *
+ * @add_interface: Called when a netdevice attached to the hardware is
+ * enabled. Because it is not called for monitor mode devices, @open
+ * and @stop must be implemented.
+ * The driver should perform any initialization it needs before
+ * the device can be enabled. The initial configuration for the
+ * interface is given in the conf parameter.
+ * The callback may refuse to add an interface by returning a
+ * negative error code (which will be seen in userspace.)
+ * Must be implemented.
+ *
+ * @remove_interface: Notifies a driver that an interface is going down.
+ * The @stop callback is called after this if it is the last interface
+ * and no monitor interfaces are present.
+ * When all interfaces are removed, the MAC address in the hardware
+ * must be cleared so the device no longer acknowledges packets,
+ * the mac_addr member of the conf structure is, however, set to the
+ * MAC address of the device going away.
+ * Hence, this callback must be implemented.
+ *
+ * @config: Handler for configuration requests. IEEE 802.11 code calls this
+ * function to change hardware configuration, e.g., channel.
+ *
+ * @config_interface: Handler for configuration requests related to interfaces
+ * (e.g. BSSID changes.)
+ *
+ * @configure_filter: Configure the device's RX filter.
+ * See the section "Frame filtering" for more information.
+ * This callback must be implemented and atomic.
+ *
+ * @set_tim: Set TIM bit. If the hardware/firmware takes care of beacon
+ * generation (that is, %IEEE80211_HW_HOST_GEN_BEACON_TEMPLATE is set)
+ * mac80211 calls this function when a TIM bit must be set or cleared
+ * for a given AID. Must be atomic.
+ *
+ * @set_key: See the section "Hardware crypto acceleration"
+ * This callback can sleep, and is only called between add_interface
+ * and remove_interface calls, i.e. while the interface with the
+ * given local_address is enabled.
+ *
+ * @hw_scan: Ask the hardware to service the scan request, no need to start
+ * the scan state machine in stack.
+ *
+ * @get_stats: return low-level statistics
+ *
+ * @get_sequence_counter: For devices that have internal sequence counters this
+ * callback allows mac80211 to access the current value of a counter.
+ * This callback seems not well-defined, tell us if you need it.
+ *
+ * @set_rts_threshold: Configuration of RTS threshold (if device needs it)
+ *
+ * @set_frag_threshold: Configuration of fragmentation threshold. Assign this if
+ * the device does fragmentation by itself; if this method is assigned then
+ * the stack will not do fragmentation.
+ *
+ * @set_retry_limit: Configuration of retry limits (if device needs it)
+ *
+ * @sta_notify: Notifies low level driver about addition or removal
+ * of assocaited station or AP.
+ *
+ * @erp_ie_changed: Handle ERP IE change notifications. Must be atomic.
+ *
+ * @conf_tx: Configure TX queue parameters (EDCF (aifs, cw_min, cw_max),
+ * bursting) for a hardware TX queue. The @queue parameter uses the
+ * %IEEE80211_TX_QUEUE_* constants. Must be atomic.
+ *
+ * @get_tx_stats: Get statistics of the current TX queue status. This is used
+ * to get number of currently queued packets (queue length), maximum queue
+ * size (limit), and total number of packets sent using each TX queue
+ * (count). This information is used for WMM to find out which TX
+ * queues have room for more packets and by hostapd to provide
+ * statistics about the current queueing state to external programs.
+ *
+ * @get_tsf: Get the current TSF timer value from firmware/hardware. Currently,
+ * this is only used for IBSS mode debugging and, as such, is not a
+ * required function. Must be atomic.
+ *
+ * @reset_tsf: Reset the TSF timer and allow firmware/hardware to synchronize
+ * with other STAs in the IBSS. This is only used in IBSS mode. This
+ * function is optional if the firmware/hardware takes full care of
+ * TSF synchronization.
+ *
+ * @beacon_update: Setup beacon data for IBSS beacons. Unlike access point,
+ * IBSS uses a fixed beacon frame which is configured using this
+ * function.
+ * If the driver returns success (0) from this callback, it owns
+ * the skb. That means the driver is responsible to kfree_skb() it.
+ * The control structure is not dynamically allocated. That means the
+ * driver does not own the pointer and if it needs it somewhere
+ * outside of the context of this function, it must copy it
+ * somewhere else.
+ * This handler is required only for IBSS mode.
+ *
+ * @tx_last_beacon: Determine whether the last IBSS beacon was sent by us.
+ * This is needed only for IBSS mode and the result of this function is
+ * used to determine whether to reply to Probe Requests.
+ */