/*
 * mac80211 <-> driver interface
 *
 * Copyright 2002-2005, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
 * Copyright 2007-2010	Johannes Berg <johannes@sipsolutions.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#ifndef MAC80211_H
#define MAC80211_H

#include <linux/kernel.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/wireless.h>
#include <linux/device.h>
#include <linux/ieee80211.h>
#include <net/cfg80211.h>

/**
 * DOC: Introduction
 *
 * mac80211 is the Linux stack for 802.11 hardware that implements
 * only partial functionality in hard- or firmware. This document
 * defines the interface between mac80211 and low-level hardware
 * drivers.
 */

/**
 * DOC: Calling mac80211 from interrupts
 *
 * Only ieee80211_tx_status_irqsafe() and ieee80211_rx_irqsafe() can be
 * called in hardware interrupt context. The low-level driver must not call any
 * other functions in hardware interrupt context. If there is a need for such
 * call, the low-level driver should first ACK the interrupt and perform the
 * IEEE 802.11 code call after this, e.g. from a scheduled workqueue or even
 * tasklet function.
 *
 * NOTE: If the driver opts to use the _irqsafe() functions, it may not also
 *	 use the non-IRQ-safe functions!
 */

/**
 * DOC: Warning
 *
 * If you're reading this document and not the header file itself, it will
 * be incomplete because not all documentation has been converted yet.
 */

/**
 * DOC: Frame format
 *
 * As a general rule, when frames are passed between mac80211 and the driver,
 * they start with the IEEE 802.11 header and include the same octets that are
 * sent over the air except for the FCS which should be calculated by the
 * hardware.
 *
 * There are, however, various exceptions to this rule for advanced features:
 *
 * The first exception is for hardware encryption and decryption offload
 * where the IV/ICV may or may not be generated in hardware.
 *
 * Secondly, when the hardware handles fragmentation, the frame handed to
 * the driver from mac80211 is the MSDU, not the MPDU.
 *
 * Finally, for received frames, the driver is able to indicate that it has
 * filled a radiotap header and put that in front of the frame; if it does
 * not do so then mac80211 may add this under certain circumstances.
 */

/**
 * DOC: mac80211 workqueue
 *
 * mac80211 provides its own workqueue for drivers and internal mac80211 use.
 * The workqueue is a single threaded workqueue and can only be accessed by
 * helpers for sanity checking. Drivers must ensure all work added onto the
 * mac80211 workqueue should be cancelled on the driver stop() callback.
 *
 * mac80211 will flushed the workqueue upon interface removal and during
 * suspend.
 *
 * All work performed on the mac80211 workqueue must not acquire the RTNL lock.
 *
 */

/**
 * enum ieee80211_max_queues - maximum number of queues
 *
 * @IEEE80211_MAX_QUEUES: Maximum number of regular device queues.
 */
enum ieee80211_max_queues {
	IEEE80211_MAX_QUEUES =		4,
};

/**
 * struct ieee80211_tx_queue_params - transmit queue configuration
 *
 * The information provided in this structure is required for QoS
 * transmit queue configuration. Cf. IEEE 802.11 7.3.2.29.
 *
 * @aifs: arbitration interframe space [0..255]
 * @cw_min: minimum contention window [a value of the form
 *	2^n-1 in the range 1..32767]
 * @cw_max: maximum contention window [like @cw_min]
 * @txop: maximum burst time in units of 32 usecs, 0 meaning disabled
 * @uapsd: is U-APSD mode enabled for the queue
 */
struct ieee80211_tx_queue_params {
	u16 txop;
	u16 cw_min;
	u16 cw_max;
	u8 aifs;
	bool uapsd;
};

struct ieee80211_low_level_stats {
	unsigned int dot11ACKFailureCount;
	unsigned int dot11RTSFailureCount;
	unsigned int dot11FCSErrorCount;
	unsigned int dot11RTSSuccessCount;
};

/**
 * enum ieee80211_bss_change - BSS change notification flags
 *
 * These flags are used with the bss_info_changed() callback
 * to indicate which BSS parameter changed.
 *
 * @BSS_CHANGED_ASSOC: association status changed (associated/disassociated),
 *	also implies a change in the AID.
 * @BSS_CHANGED_ERP_CTS_PROT: CTS protection changed
 * @BSS_CHANGED_ERP_PREAMBLE: preamble changed
 * @BSS_CHANGED_ERP_SLOT: slot timing changed
 * @BSS_CHANGED_HT: 802.11n parameters changed
 * @BSS_CHANGED_BASIC_RATES: Basic rateset changed
 * @BSS_CHANGED_BEACON_INT: Beacon interval changed
 * @BSS_CHANGED_BSSID: BSSID changed, for whatever
 *	reason (IBSS and managed mode)
 * @BSS_CHANGED_BEACON: Beacon data changed, retrieve
 *	new beacon (beaconing modes)
 * @BSS_CHANGED_BEACON_ENABLED: Beaconing should be
 *	enabled/disabled (beaconing modes)
 * @BSS_CHANGED_CQM: Connection quality monitor config changed
 */
enum ieee80211_bss_change {
	BSS_CHANGED_ASSOC		= 1<<0,
	BSS_CHANGED_ERP_CTS_PROT	= 1<<1,
	BSS_CHANGED_ERP_PREAMBLE	= 1<<2,
	BSS_CHANGED_ERP_SLOT		= 1<<3,
	BSS_CHANGED_HT                  = 1<<4,
	BSS_CHANGED_BASIC_RATES		= 1<<5,
	BSS_CHANGED_BEACON_INT		= 1<<6,
	BSS_CHANGED_BSSID		= 1<<7,
	BSS_CHANGED_BEACON		= 1<<8,
	BSS_CHANGED_BEACON_ENABLED	= 1<<9,
	BSS_CHANGED_CQM			= 1<<10,
};

/**
 * struct ieee80211_bss_conf - holds the BSS's changing parameters
 *
 * This structure keeps information about a BSS (and an association
 * to that BSS) that can change during the lifetime of the BSS.
 *
 * @assoc: association status
 * @aid: association ID number, valid only when @assoc is true
 * @use_cts_prot: use CTS protection
 * @use_short_preamble: use 802.11b short preamble;
 *	if the hardware cannot handle this it must set the
 *	IEEE80211_HW_2GHZ_SHORT_PREAMBLE_INCAPABLE hardware flag
 * @use_short_slot: use short slot time (only relevant for ERP);
 *	if the hardware cannot handle this it must set the
 *	IEEE80211_HW_2GHZ_SHORT_SLOT_INCAPABLE hardware flag
 * @dtim_period: num of beacons before the next DTIM, for beaconing,
 *	not valid in station mode (cf. hw conf ps_dtim_period)
 * @timestamp: beacon timestamp
 * @beacon_int: beacon interval
 * @assoc_capability: capabilities taken from assoc resp
 * @basic_rates: bitmap of basic rates, each bit stands for an
 *	index into the rate table configured by the driver in
 *	the current band.
 * @bssid: The BSSID for this BSS
 * @enable_beacon: whether beaconing should be enabled or not
 * @ht_operation_mode: HT operation mode (like in &struct ieee80211_ht_info).
 *	This field is only valid when the channel type is one of the HT types.
 * @cqm_rssi_thold: Connection quality monitor RSSI threshold, a zero value
 *	implies disabled
 * @cqm_rssi_hyst: Connection quality monitor RSSI hysteresis
 */
struct ieee80211_bss_conf {
	const u8 *bssid;
	/* association related data */
	bool assoc;
	u16 aid;
	/* erp related data */
	bool use_cts_prot;
	bool use_short_preamble;
	bool use_short_slot;
	bool enable_beacon;
	u8 dtim_period;
	u16 beacon_int;
	u16 assoc_capability;
	u64 timestamp;
	u32 basic_rates;
	u16 ht_operation_mode;
	s32 cqm_rssi_thold;
	u32 cqm_rssi_hyst;
};

/**
 * enum mac80211_tx_control_flags - flags to describe transmission information/status
 *
 * These flags are used with the @flags member of &ieee80211_tx_info.
 *
 * @IEEE80211_TX_CTL_REQ_TX_STATUS: require TX status callback for this frame.
 * @IEEE80211_TX_CTL_ASSIGN_SEQ: The driver has to assign a sequence
 *	number to this frame, taking care of not overwriting the fragment
 *	number and increasing the sequence number only when the
 *	IEEE80211_TX_CTL_FIRST_FRAGMENT flag is set. mac80211 will properly
 *	assign sequence numbers to QoS-data frames but cannot do so correctly
 *	for non-QoS-data and management frames because beacons need them from
 *	that counter as well and mac80211 cannot guarantee proper sequencing.
 *	If this flag is set, the driver should instruct the hardware to
 *	assign a sequence number to the frame or assign one itself. Cf. IEEE
 *	802.11-2007 7.1.3.4.1 paragraph 3. This flag will always be set for
 *	beacons and always be clear for frames without a sequence number field.
 * @IEEE80211_TX_CTL_NO_ACK: tell the low level not to wait for an ack
 * @IEEE80211_TX_CTL_CLEAR_PS_FILT: clear powersave filter for destination
 *	station
 * @IEEE80211_TX_CTL_FIRST_FRAGMENT: this is a first fragment of the frame
 * @IEEE80211_TX_CTL_SEND_AFTER_DTIM: send this frame after DTIM beacon
 * @IEEE80211_TX_CTL_AMPDU: this frame should be sent as part of an A-MPDU
 * @IEEE80211_TX_CTL_INJECTED: Frame was injected, internal to mac80211.
 * @IEEE80211_TX_STAT_TX_FILTERED: The frame was not transmitted
 *	because the destination STA was in powersave mode. Note that to
 *	avoid race conditions, the filter must be set by the hardware or
 *	firmware upon receiving a frame that indicates that the station
 *	went to sleep (must be done on device to filter frames already on
 *	the queue) and may only be unset after mac80211 gives the OK for
 *	that by setting the IEEE80211_TX_CTL_CLEAR_PS_FILT (see above),
 *	since only then is it guaranteed that no more frames are in the
 *	hardware queue.
 * @IEEE80211_TX_STAT_ACK: Frame was acknowledged
 * @IEEE80211_TX_STAT_AMPDU: The frame was aggregated, so status
 * 	is for the whole aggregation.
 * @IEEE80211_TX_STAT_AMPDU_NO_BACK: no block ack was returned,
 * 	so consider using block ack request (BAR).
 * @IEEE80211_TX_CTL_RATE_CTRL_PROBE: internal to mac80211, can be
 *	set by rate control algorithms to indicate probe rate, will
 *	be cleared for fragmented frames (except on the last fragment)
 * @IEEE80211_TX_INTFL_NEED_TXPROCESSING: completely internal to mac80211,
 *	used to indicate that a pending frame requires TX processing before
 *	it can be sent out.
 * @IEEE80211_TX_INTFL_RETRIED: completely internal to mac80211,
 *	used to indicate that a frame was already retried due to PS
 * @IEEE80211_TX_INTFL_DONT_ENCRYPT: completely internal to mac80211,
 *	used to indicate frame should not be encrypted
 * @IEEE80211_TX_CTL_PSPOLL_RESPONSE: (internal?)
 *	This frame is a response to a PS-poll frame and should be sent
 *	although the station is in powersave mode.
 * @IEEE80211_TX_CTL_MORE_FRAMES: More frames will be passed to the
 *	transmit function after the current frame, this can be used
 *	by drivers to kick the DMA queue only if unset or when the
 *	queue gets full.
 * @IEEE80211_TX_INTFL_RETRANSMISSION: This frame is being retransmitted
 *	after TX status because the destination was asleep, it must not
 *	be modified again (no seqno assignment, crypto, etc.)
 * @IEEE80211_TX_INTFL_HAS_RADIOTAP: This frame was injected and still
 *	has a radiotap header at skb->data.
 * @IEEE80211_TX_INTFL_NL80211_FRAME_TX: Frame was requested through nl80211
 *	MLME command (internal to mac80211 to figure out whether to send TX
 *	status to user space)
 */
enum mac80211_tx_control_flags {
	IEEE80211_TX_CTL_REQ_TX_STATUS		= BIT(0),
	IEEE80211_TX_CTL_ASSIGN_SEQ		= BIT(1),
	IEEE80211_TX_CTL_NO_ACK			= BIT(2),
	IEEE80211_TX_CTL_CLEAR_PS_FILT		= BIT(3),
	IEEE80211_TX_CTL_FIRST_FRAGMENT		= BIT(4),
	IEEE80211_TX_CTL_SEND_AFTER_DTIM	= BIT(5),
	IEEE80211_TX_CTL_AMPDU			= BIT(6),
	IEEE80211_TX_CTL_INJECTED		= BIT(7),
	IEEE80211_TX_STAT_TX_FILTERED		= BIT(8),
	IEEE80211_TX_STAT_ACK			= BIT(9),
	IEEE80211_TX_STAT_AMPDU			= BIT(10),
	IEEE80211_TX_STAT_AMPDU_NO_BACK		= BIT(11),
	IEEE80211_TX_CTL_RATE_CTRL_PROBE	= BIT(12),
	IEEE80211_TX_INTFL_NEED_TXPROCESSING	= BIT(14),
	IEEE80211_TX_INTFL_RETRIED		= BIT(15),
	IEEE80211_TX_INTFL_DONT_ENCRYPT		= BIT(16),
	IEEE80211_TX_CTL_PSPOLL_RESPONSE	= BIT(17),
	IEEE80211_TX_CTL_MORE_FRAMES		= BIT(18),
	IEEE80211_TX_INTFL_RETRANSMISSION	= BIT(19),
	IEEE80211_TX_INTFL_HAS_RADIOTAP		= BIT(20),
	IEEE80211_TX_INTFL_NL80211_FRAME_TX	= BIT(21),
};

/**
 * enum mac80211_rate_control_flags - per-rate flags set by the
 *	Rate Control algorithm.
 *
 * These flags are set by the Rate control algorithm for each rate during tx,
 * in the @flags member of struct ieee80211_tx_rate.
 *
 * @IEEE80211_TX_RC_USE_RTS_CTS: Use RTS/CTS exchange for this rate.
 * @IEEE80211_TX_RC_USE_CTS_PROTECT: CTS-to-self protection is required.
 *	This is set if the current BSS requires ERP protection.
 * @IEEE80211_TX_RC_USE_SHORT_PREAMBLE: Use short preamble.
 * @IEEE80211_TX_RC_MCS: HT rate.
 * @IEEE80211_TX_RC_GREEN_FIELD: Indicates whether this rate should be used in
 *	Greenfield mode.
 * @IEEE80211_TX_RC_40_MHZ_WIDTH: Indicates if the Channel Width should be 40 MHz.
 * @IEEE80211_TX_RC_DUP_DATA: The frame should be transmitted on both of the
 *	adjacent 20 MHz channels, if the current channel type is
 *	NL80211_CHAN_HT40MINUS or NL80211_CHAN_HT40PLUS.
 * @IEEE80211_TX_RC_SHORT_GI: Short Guard interval should be used for this rate.
 */
enum mac80211_rate_control_flags {
	IEEE80211_TX_RC_USE_RTS_CTS		= BIT(0),
	IEEE80211_TX_RC_USE_CTS_PROTECT		= BIT(1),
	IEEE80211_TX_RC_USE_SHORT_PREAMBLE	= BIT(2),

	/* rate index is an MCS rate number instead of an index */
	IEEE80211_TX_RC_MCS			= BIT(3),
	IEEE80211_TX_RC_GREEN_FIELD		= BIT(4),
	IEEE80211_TX_RC_40_MHZ_WIDTH		= BIT(5),
	IEEE80211_TX_RC_DUP_DATA		= BIT(6),
	IEEE80211_TX_RC_SHORT_GI		= BIT(7),
};


/* there are 40 bytes if you don't need the rateset to be kept */
#define IEEE80211_TX_INFO_DRIVER_DATA_SIZE 40

/* if you do need the rateset, then you have less space */
#define IEEE80211_TX_INFO_RATE_DRIVER_DATA_SIZE 24

/* maximum number of rate stages */
#define IEEE80211_TX_MAX_RATES	5

/**
 * struct ieee80211_tx_rate - rate selection/status
 *
 * @idx: rate index to attempt to send with
 * @flags: rate control flags (&enum mac80211_rate_control_flags)
 * @count: number of tries in this rate before going to the next rate
 *
 * A value of -1 for @idx indicates an invalid rate and, if used
 * in an array of retry rates, that no more rates should be tried.
 *
 * When used for transmit status reporting, the driver should
 * always report the rate along with the flags it used.
 *
 * &struct ieee80211_tx_info contains an array of these structs
 * in the control information, and it will be filled by the rate
 * control algorithm according to what should be sent. For example,
 * if this array contains, in the format { <idx>, <count> } the
 * information
 *    { 3, 2 }, { 2, 2 }, { 1, 4 }, { -1, 0 }, { -1, 0 }
 * then this means that the frame should be transmitted
 * up to twice at rate 3, up to twice at rate 2, and up to four
 * times at rate 1 if it doesn't get acknowledged. Say it gets
 * acknowledged by the peer after the fifth attempt, the status
 * information should then contain
 *   { 3, 2 }, { 2, 2 }, { 1, 1 }, { -1, 0 } ...
 * since it was transmitted twice at rate 3, twice at rate 2
 * and once at rate 1 after which we received an acknowledgement.
 */
struct ieee80211_tx_rate {
	s8 idx;
	u8 count;
	u8 flags;
} __attribute__((packed));

/**
 * struct ieee80211_tx_info - skb transmit information
 *
 * This structure is placed in skb->cb for three uses:
 *  (1) mac80211 TX control - mac80211 tells the driver what to do
 *  (2) driver internal use (if applicable)
 *  (3) TX status information - driver tells mac80211 what happened
 *
 * The TX control's sta pointer is only valid during the ->tx call,
 * it may be NULL.
 *
 * @flags: transmit info flags, defined above
 * @band: the band to transmit on (use for checking for races)
 * @antenna_sel_tx: antenna to use, 0 for automatic diversity
 * @pad: padding, ignore
 * @control: union for control data
 * @status: union for status data
 * @driver_data: array of driver_data pointers
 * @ampdu_ack_len: number of acked aggregated frames.
 * 	relevant only if IEEE80211_TX_STATUS_AMPDU was set.
 * @ampdu_ack_map: block ack bit map for the aggregation.
 * 	relevant only if IEEE80211_TX_STATUS_AMPDU was set.
 * @ampdu_len: number of aggregated frames.
 * 	relevant only if IEEE80211_TX_STATUS_AMPDU was set.
 * @ack_signal: signal strength of the ACK frame
 */
struct ieee80211_tx_info {
	/* common information */
	u32 flags;
	u8 band;

	u8 antenna_sel_tx;

	/* 2 byte hole */
	u8 pad[2];

	union {
		struct {
			union {
				/* rate control */
				struct {
					struct ieee80211_tx_rate rates[
						IEEE80211_TX_MAX_RATES];
					s8 rts_cts_rate_idx;
				};
				/* only needed before rate control */
				unsigned long jiffies;
			};
			/* NB: vif can be NULL for injected frames */
			struct ieee80211_vif *vif;
			struct ieee80211_key_conf *hw_key;
			struct ieee80211_sta *sta;
		} control;
		struct {
			struct ieee80211_tx_rate rates[IEEE80211_TX_MAX_RATES];
			u8 ampdu_ack_len;
			u64 ampdu_ack_map;
			int ack_signal;
			u8 ampdu_len;
			/* 7 bytes free */
		} status;
		struct {
			struct ieee80211_tx_rate driver_rates[
				IEEE80211_TX_MAX_RATES];
			void *rate_driver_data[
				IEEE80211_TX_INFO_RATE_DRIVER_DATA_SIZE / sizeof(void *)];
		};
		void *driver_data[
			IEEE80211_TX_INFO_DRIVER_DATA_SIZE / sizeof(void *)];
	};
};

static inline struct ieee80211_tx_info *IEEE80211_SKB_CB(struct sk_buff *skb)
{
	return (struct ieee80211_tx_info *)skb->cb;
}

static inline struct ieee80211_rx_status *IEEE80211_SKB_RXCB(struct sk_buff *skb)
{
	return (struct ieee80211_rx_status *)skb->cb;
}

/**
 * ieee80211_tx_info_clear_status - clear TX status
 *
 * @info: The &struct ieee80211_tx_info to be cleared.
 *
 * When the driver passes an skb back to mac80211, it must report
 * a number of things in TX status. This function clears everything
 * in the TX status but the rate control information (it does clear
 * the count since you need to fill that in anyway).
 *
 * NOTE: You can only use this function if you do NOT use
 *	 info->driver_data! Use info->rate_driver_data
 *	 instead if you need only the less space that allows.
 */
static inline void
ieee80211_tx_info_clear_status(struct ieee80211_tx_info *info)
{
	int i;

	BUILD_BUG_ON(offsetof(struct ieee80211_tx_info, status.rates) !=
		     offsetof(struct ieee80211_tx_info, control.rates));
	BUILD_BUG_ON(offsetof(struct ieee80211_tx_info, status.rates) !=
		     offsetof(struct ieee80211_tx_info, driver_rates));
	BUILD_BUG_ON(offsetof(struct ieee80211_tx_info, status.rates) != 8);
	/* clear the rate counts */
	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++)
		info->status.rates[i].count = 0;

	BUILD_BUG_ON(
	    offsetof(struct ieee80211_tx_info, status.ampdu_ack_len) != 23);
	memset(&info->status.ampdu_ack_len, 0,
	       sizeof(struct ieee80211_tx_info) -
	       offsetof(struct ieee80211_tx_info, status.ampdu_ack_len));
}


/**
 * enum mac80211_rx_flags - receive flags
 *
 * These flags are used with the @flag member of &struct ieee80211_rx_status.
 * @RX_FLAG_MMIC_ERROR: Michael MIC error was reported on this frame.
 *	Use together with %RX_FLAG_MMIC_STRIPPED.
 * @RX_FLAG_DECRYPTED: This frame was decrypted in hardware.
 * @RX_FLAG_MMIC_STRIPPED: the Michael MIC is stripped off this frame,
 *	verification has been done by the hardware.
 * @RX_FLAG_IV_STRIPPED: The IV/ICV are stripped from this frame.
 *	If this flag is set, the stack cannot do any replay detection
 *	hence the driver or hardware will have to do that.
 * @RX_FLAG_FAILED_FCS_CRC: Set this flag if the FCS check failed on
 *	the frame.
 * @RX_FLAG_FAILED_PLCP_CRC: Set this flag if the PCLP check failed on
 *	the frame.
 * @RX_FLAG_TSFT: The timestamp passed in the RX status (@mactime field)
 *	is valid. This is useful in monitor mode and necessary for beacon frames
 *	to enable IBSS merging.
 * @RX_FLAG_SHORTPRE: Short preamble was used for this frame
 * @RX_FLAG_HT: HT MCS was used and rate_idx is MCS index
 * @RX_FLAG_40MHZ: HT40 (40 MHz) was used
 * @RX_FLAG_SHORT_GI: Short guard interval was used
 * @RX_FLAG_INTERNAL_CMTR: set internally after frame was reported
 *	on cooked monitor to avoid double-reporting it for multiple
 *	virtual interfaces
 */
enum mac80211_rx_flags {
	RX_FLAG_MMIC_ERROR	= 1<<0,
	RX_FLAG_DECRYPTED	= 1<<1,
	RX_FLAG_MMIC_STRIPPED	= 1<<3,
	RX_FLAG_IV_STRIPPED	= 1<<4,
	RX_FLAG_FAILED_FCS_CRC	= 1<<5,
	RX_FLAG_FAILED_PLCP_CRC = 1<<6,
	RX_FLAG_TSFT		= 1<<7,
	RX_FLAG_SHORTPRE	= 1<<8,
	RX_FLAG_HT		= 1<<9,
	RX_FLAG_40MHZ		= 1<<10,
	RX_FLAG_SHORT_GI	= 1<<11,
	RX_FLAG_INTERNAL_CMTR	= 1<<12,
};

/**
 * struct ieee80211_rx_status - receive status
 *
 * The low-level driver should provide this information (the subset
 * supported by hardware) to the 802.11 code with each received
 * frame, in the skb's control buffer (cb).
 *
 * @mactime: value in microseconds of the 64-bit Time Synchronization Function
 * 	(TSF) timer when the first data symbol (MPDU) arrived at the hardware.
 * @band: the active band when this frame was received
 * @freq: frequency the radio was tuned to when receiving this frame, in MHz
 * @signal: signal strength when receiving this frame, either in dBm, in dB or
 *	unspecified depending on the hardware capabilities flags
 *	@IEEE80211_HW_SIGNAL_*
 * @noise: noise when receiving this frame, in dBm (DEPRECATED).
 * @antenna: antenna used
 * @rate_idx: index of data rate into band's supported rates or MCS index if
 *	HT rates are use (RX_FLAG_HT)
 * @flag: %RX_FLAG_*
 */
struct ieee80211_rx_status {
	u64 mactime;
	enum ieee80211_band band;
	int freq;
	int signal;
	int noise __deprecated;
	int antenna;
	int rate_idx;
	int flag;
};

/**
 * enum ieee80211_conf_flags - configuration flags
 *
 * Flags to define PHY configuration options
 *
 * @IEEE80211_CONF_MONITOR: there's a monitor interface present -- use this
 *	to determine for example whether to calculate timestamps for packets
 *	or not, do not use instead of filter flags!
 * @IEEE80211_CONF_PS: Enable 802.11 power save mode (managed mode only).
 *	This is the power save mode defined by IEEE 802.11-2007 section 11.2,
 *	meaning that the hardware still wakes up for beacons, is able to
 *	transmit frames and receive the possible acknowledgment frames.
 *	Not to be confused with hardware specific wakeup/sleep states,
 *	driver is responsible for that. See the section "Powersave support"
 *	for more.
 * @IEEE80211_CONF_IDLE: The device is running, but idle; if the flag is set
 *	the driver should be prepared to handle configuration requests but
 *	may turn the device off as much as possible. Typically, this flag will
 *	be set when an interface is set UP but not associated or scanning, but
 *	it can also be unset in that case when monitor interfaces are active.
 * @IEEE80211_CONF_QOS: Enable 802.11e QoS also know as WMM (Wireless
 *      Multimedia). On some drivers (iwlwifi is one of know) we have
 *      to enable/disable QoS explicitly.
 */
enum ieee80211_conf_flags {
	IEEE80211_CONF_MONITOR		= (1<<0),
	IEEE80211_CONF_PS		= (1<<1),
	IEEE80211_CONF_IDLE		= (1<<2),
	IEEE80211_CONF_QOS		= (1<<3),
};


/**
 * enum ieee80211_conf_changed - denotes which configuration changed
 *
 * @IEEE80211_CONF_CHANGE_LISTEN_INTERVAL: the listen interval changed
 * @IEEE80211_CONF_CHANGE_MONITOR: the monitor flag changed
 * @IEEE80211_CONF_CHANGE_PS: the PS flag or dynamic PS timeout changed
 * @IEEE80211_CONF_CHANGE_POWER: the TX power changed
 * @IEEE80211_CONF_CHANGE_CHANNEL: the channel/channel_type changed
 * @IEEE80211_CONF_CHANGE_RETRY_LIMITS: retry limits changed
 * @IEEE80211_CONF_CHANGE_IDLE: Idle flag changed
 * @IEEE80211_CONF_CHANGE_SMPS: Spatial multiplexing powersave mode changed
 */
enum ieee80211_conf_changed {
	IEEE80211_CONF_CHANGE_SMPS		= BIT(1),
	IEEE80211_CONF_CHANGE_LISTEN_INTERVAL	= BIT(2),
	IEEE80211_CONF_CHANGE_MONITOR		= BIT(3),
	IEEE80211_CONF_CHANGE_PS		= BIT(4),
	IEEE80211_CONF_CHANGE_POWER		= BIT(5),
	IEEE80211_CONF_CHANGE_CHANNEL		= BIT(6),
	IEEE80211_CONF_CHANGE_RETRY_LIMITS	= BIT(7),
	IEEE80211_CONF_CHANGE_IDLE		= BIT(8),
	IEEE80211_CONF_CHANGE_QOS		= BIT(9),
};

/**
 * enum ieee80211_smps_mode - spatial multiplexing power save mode
 *
 * @IEEE80211_SMPS_AUTOMATIC: automatic
 * @IEEE80211_SMPS_OFF: off
 * @IEEE80211_SMPS_STATIC: static
 * @IEEE80211_SMPS_DYNAMIC: dynamic
 * @IEEE80211_SMPS_NUM_MODES: internal, don't use
 */
enum ieee80211_smps_mode {
	IEEE80211_SMPS_AUTOMATIC,
	IEEE80211_SMPS_OFF,
	IEEE80211_SMPS_STATIC,
	IEEE80211_SMPS_DYNAMIC,

	/* keep last */
	IEEE80211_SMPS_NUM_MODES,
};

/**
 * struct ieee80211_conf - configuration of the device
 *
 * This struct indicates how the driver shall configure the hardware.
 *
 * @flags: configuration flags defined above
 *
 * @listen_interval: listen interval in units of beacon interval
 * @max_sleep_period: the maximum number of beacon intervals to sleep for
 *	before checking the beacon for a TIM bit (managed mode only); this
 *	value will be only achievable between DTIM frames, the hardware
 *	needs to check for the multicast traffic bit in DTIM beacons.
 *	This variable is valid only when the CONF_PS flag is set.
 * @ps_dtim_period: The DTIM period of the AP we're connected to, for use
 *	in power saving. Power saving will not be enabled until a beacon
 *	has been received and the DTIM period is known.
 * @dynamic_ps_timeout: The dynamic powersave timeout (in ms), see the
 *	powersave documentation below. This variable is valid only when
 *	the CONF_PS flag is set.
 *
 * @power_level: requested transmit power (in dBm)
 *
 * @channel: the channel to tune to
 * @channel_type: the channel (HT) type
 *
 * @long_frame_max_tx_count: Maximum number of transmissions for a "long" frame
 *    (a frame not RTS protected), called "dot11LongRetryLimit" in 802.11,
 *    but actually means the number of transmissions not the number of retries
 * @short_frame_max_tx_count: Maximum number of transmissions for a "short"
 *    frame, called "dot11ShortRetryLimit" in 802.11, but actually means the
 *    number of transmissions not the number of retries
 *
 * @smps_mode: spatial multiplexing powersave mode; note that
 *	%IEEE80211_SMPS_STATIC is used when the device is not
 *	configured for an HT channel
 */
struct ieee80211_conf {
	u32 flags;
	int power_level, dynamic_ps_timeout;
	int max_sleep_period;

	u16 listen_interval;
	u8 ps_dtim_period;

	u8 long_frame_max_tx_count, short_frame_max_tx_count;

	struct ieee80211_channel *channel;
	enum nl80211_channel_type channel_type;
	enum ieee80211_smps_mode smps_mode;
};

/**
 * struct ieee80211_vif - per-interface data
 *
 * Data in this structure is continually present for driver
 * use during the life of a virtual interface.
 *
 * @type: type of this virtual interface
 * @bss_conf: BSS configuration for this interface, either our own
 *	or the BSS we're associated to
 * @addr: address of this interface
 * @drv_priv: data area for driver use, will always be aligned to
 *	sizeof(void *).
 */
struct ieee80211_vif {
	enum nl80211_iftype type;
	struct ieee80211_bss_conf bss_conf;
	u8 addr[ETH_ALEN];
	/* must be last */
	u8 drv_priv[0] __attribute__((__aligned__(sizeof(void *))));
};

static inline bool ieee80211_vif_is_mesh(struct ieee80211_vif *vif)
{
#ifdef CONFIG_MAC80211_MESH
	return vif->type == NL80211_IFTYPE_MESH_POINT;
#endif
	return false;
}

/**
 * enum ieee80211_key_alg - key algorithm
 * @ALG_WEP: WEP40 or WEP104
 * @ALG_TKIP: TKIP
 * @ALG_CCMP: CCMP (AES)
 * @ALG_AES_CMAC: AES-128-CMAC
 */
enum ieee80211_key_alg {
	ALG_WEP,
	ALG_TKIP,
	ALG_CCMP,
	ALG_AES_CMAC,
};

/**
 * enum ieee80211_key_flags - key flags
 *
 * These flags are used for communication about keys between the driver
 * and mac80211, with the @flags parameter of &struct ieee80211_key_conf.
 *
 * @IEEE80211_KEY_FLAG_WMM_STA: Set by mac80211, this flag indicates
 *	that the STA this key will be used with could be using QoS.
 * @IEEE80211_KEY_FLAG_GENERATE_IV: This flag should be set by the
 *	driver to indicate that it requires IV generation for this
 *	particular key.
 * @IEEE80211_KEY_FLAG_GENERATE_MMIC: This flag should be set by
 *	the driver for a TKIP key if it requires Michael MIC
 *	generation in software.
 * @IEEE80211_KEY_FLAG_PAIRWISE: Set by mac80211, this flag indicates
 *	that the key is pairwise rather then a shared key.
 * @IEEE80211_KEY_FLAG_SW_MGMT: This flag should be set by the driver for a
 *	CCMP key if it requires CCMP encryption of management frames (MFP) to
 *	be done in software.
 */
enum ieee80211_key_flags {
	IEEE80211_KEY_FLAG_WMM_STA	= 1<<0,
	IEEE80211_KEY_FLAG_GENERATE_IV	= 1<<1,
	IEEE80211_KEY_FLAG_GENERATE_MMIC= 1<<2,
	IEEE80211_KEY_FLAG_PAIRWISE	= 1<<3,
	IEEE80211_KEY_FLAG_SW_MGMT	= 1<<4,
};

/**
 * struct ieee80211_key_conf - key information
 *
 * This key information is given by mac80211 to the driver by
 * the set_key() callback in &struct ieee80211_ops.
 *
 * @hw_key_idx: To be set by the driver, this is the key index the driver
 *	wants to be given when a frame is transmitted and needs to be
 *	encrypted in hardware.
 * @alg: The key algorithm.
 * @flags: key flags, see &enum ieee80211_key_flags.
 * @keyidx: the key index (0-3)
 * @keylen: key material length
 * @key: key material. For ALG_TKIP the key is encoded as a 256-bit (32 byte)
 * 	data block:
 * 	- Temporal Encryption Key (128 bits)
 * 	- Temporal Authenticator Tx MIC Key (64 bits)
 * 	- Temporal Authenticator Rx MIC Key (64 bits)
 * @icv_len: The ICV length for this key type
 * @iv_len: The IV length for this key type
 */
struct ieee80211_key_conf {
	enum ieee80211_key_alg alg;
	u8 icv_len;
	u8 iv_len;
	u8 hw_key_idx;
	u8 flags;
	s8 keyidx;
	u8 keylen;
	u8 key[0];
};

/**
 * enum set_key_cmd - key command
 *
 * Used with the set_key() callback in &struct ieee80211_ops, this
 * indicates whether a key is being removed or added.
 *
 * @SET_KEY: a key is set
 * @DISABLE_KEY: a key must be disabled
 */
enum set_key_cmd {
	SET_KEY, DISABLE_KEY,
};

/**
 * struct ieee80211_sta - station table entry
 *
 * A station table entry represents a station we are possibly
 * communicating with. Since stations are RCU-managed in
 * mac80211, any ieee80211_sta pointer you get access to must
 * either be protected by rcu_read_lock() explicitly or implicitly,
 * or you must take good care to not use such a pointer after a
 * call to your sta_remove callback that removed it.
 *
 * @addr: MAC address
 * @aid: AID we assigned to the station if we're an AP
 * @supp_rates: Bitmap of supported rates (per band)
 * @ht_cap: HT capabilities of this STA; restricted to our own TX capabilities
 * @drv_priv: data area for driver use, will always be aligned to
 *	sizeof(void *), size is determined in hw information.
 */
struct ieee80211_sta {
	u32 supp_rates[IEEE80211_NUM_BANDS];
	u8 addr[ETH_ALEN];
	u16 aid;
	struct ieee80211_sta_ht_cap ht_cap;

	/* must be last */
	u8 drv_priv[0] __attribute__((__aligned__(sizeof(void *))));
};

/**
 * enum sta_notify_cmd - sta notify command
 *
 * Used with the sta_notify() callback in &struct ieee80211_ops, this
 * indicates addition and removal of a station to station table,
 * or if a associated station made a power state transition.
 *
 * @STA_NOTIFY_ADD: (DEPRECATED) a station was added to the station table
 * @STA_NOTIFY_REMOVE: (DEPRECATED) a station being removed from the station table
 * @STA_NOTIFY_SLEEP: a station is now sleeping
 * @STA_NOTIFY_AWAKE: a sleeping station woke up
 */
enum sta_notify_cmd {
	STA_NOTIFY_ADD, STA_NOTIFY_REMOVE,
	STA_NOTIFY_SLEEP, STA_NOTIFY_AWAKE,
};

/**
 * enum ieee80211_tkip_key_type - get tkip key
 *
 * Used by drivers which need to get a tkip key for skb. Some drivers need a
 * phase 1 key, others need a phase 2 key. A single function allows the driver
 * to get the key, this enum indicates what type of key is required.
 *
 * @IEEE80211_TKIP_P1_KEY: the driver needs a phase 1 key
 * @IEEE80211_TKIP_P2_KEY: the driver needs a phase 2 key
 */
enum ieee80211_tkip_key_type {
	IEEE80211_TKIP_P1_KEY,
	IEEE80211_TKIP_P2_KEY,
};

/**
 * enum ieee80211_hw_flags - hardware flags
 *
 * These flags are used to indicate hardware capabilities to
 * the stack. Generally, flags here should have their meaning
 * done in a way that the simplest hardware doesn't need setting
 * any particular flags. There are some exceptions to this rule,
 * however, so you are advised to review these flags carefully.
 *
 * @IEEE80211_HW_HAS_RATE_CONTROL:
 *	The hardware or firmware includes rate control, and cannot be
 *	controlled by the stack. As such, no rate control algorithm
 *	should be instantiated, and the TX rate reported to userspace
 *	will be taken from the TX status instead of the rate control
 *	algorithm.
 *	Note that this requires that the driver implement a number of
 *	callbacks so it has the correct information, it needs to have
 *	the @set_rts_threshold callback and must look at the BSS config
 *	@use_cts_prot for G/N protection, @use_short_slot for slot
 *	timing in 2.4 GHz and @use_short_preamble for preambles for
 *	CCK frames.
 *
 * @IEEE80211_HW_RX_INCLUDES_FCS:
 *	Indicates that received frames passed to the stack include
 *	the FCS at the end.
 *
 * @IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING:
 *	Some wireless LAN chipsets buffer broadcast/multicast frames
 *	for power saving stations in the hardware/firmware and others
 *	rely on the host system for such buffering. This option is used
 *	to configure the IEEE 802.11 upper layer to buffer broadcast and
 *	multicast frames when there are power saving stations so that
 *	the driver can fetch them with ieee80211_get_buffered_bc().
 *
 * @IEEE80211_HW_2GHZ_SHORT_SLOT_INCAPABLE:
 *	Hardware is not capable of short slot operation on the 2.4 GHz band.
 *
 * @IEEE80211_HW_2GHZ_SHORT_PREAMBLE_INCAPABLE:
 *	Hardware is not capable of receiving frames with short preamble on
 *	the 2.4 GHz band.
 *
 * @IEEE80211_HW_SIGNAL_UNSPEC:
 *	Hardware can provide signal values but we don't know its units. We
 *	expect values between 0 and @max_signal.
 *	If possible please provide dB or dBm instead.
 *
 * @IEEE80211_HW_SIGNAL_DBM:
 *	Hardware gives signal values in dBm, decibel difference from
 *	one milliwatt. This is the preferred method since it is standardized
 *	between different devices. @max_signal does not need to be set.
 *
 * @IEEE80211_HW_NOISE_DBM:
 *	Hardware can provide noise (radio interference) values in units dBm,
 *      decibel difference from one milliwatt.
 *
 * @IEEE80211_HW_SPECTRUM_MGMT:
 * 	Hardware supports spectrum management defined in 802.11h
 * 	Measurement, Channel Switch, Quieting, TPC
 *
 * @IEEE80211_HW_AMPDU_AGGREGATION:
 *	Hardware supports 11n A-MPDU aggregation.
 *
 * @IEEE80211_HW_SUPPORTS_PS:
 *	Hardware has power save support (i.e. can go to sleep).
 *
 * @IEEE80211_HW_PS_NULLFUNC_STACK:
 *	Hardware requires nullfunc frame handling in stack, implies
 *	stack support for dynamic PS.
 *
 * @IEEE80211_HW_SUPPORTS_DYNAMIC_PS:
 *	Hardware has support for dynamic PS.
 *
 * @IEEE80211_HW_MFP_CAPABLE:
 *	Hardware supports management frame protection (MFP, IEEE 802.11w).
 *
 * @IEEE80211_HW_BEACON_FILTER:
 *	Hardware supports dropping of irrelevant beacon frames to
 *	avoid waking up cpu.
 *
 * @IEEE80211_HW_SUPPORTS_STATIC_SMPS:
 *	Hardware supports static spatial multiplexing powersave,
 *	ie. can turn off all but one chain even on HT connections
 *	that should be using more chains.
 *
 * @IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS:
 *	Hardware supports dynamic spatial multiplexing powersave,
 *	ie. can turn off all but one chain and then wake the rest
 *	up as required after, for example, rts/cts handshake.
 *
 * @IEEE80211_HW_SUPPORTS_UAPSD:
 *	Hardware supports Unscheduled Automatic Power Save Delivery
 *	(U-APSD) in managed mode. The mode is configured with
 *	conf_tx() operation.
 *
 * @IEEE80211_HW_REPORTS_TX_ACK_STATUS:
 *	Hardware can provide ack status reports of Tx frames to
 *	the stack.
 *
 * @IEEE80211_HW_CONNECTION_MONITOR:
 *      The hardware performs its own connection monitoring, including
 *      periodic keep-alives to the AP and probing the AP on beacon loss.
 *      When this flag is set, signaling beacon-loss will cause an immediate
 *      change to disassociated state.
 *
 * @IEEE80211_HW_SUPPORTS_CQM_RSSI:
 *	Hardware can do connection quality monitoring - i.e. it can monitor
 *	connection quality related parameters, such as the RSSI level and
 *	provide notifications if configured trigger levels are reached.
 *
 */
enum ieee80211_hw_flags {
	IEEE80211_HW_HAS_RATE_CONTROL			= 1<<0,
	IEEE80211_HW_RX_INCLUDES_FCS			= 1<<1,
	IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING	= 1<<2,
	IEEE80211_HW_2GHZ_SHORT_SLOT_INCAPABLE		= 1<<3,
	IEEE80211_HW_2GHZ_SHORT_PREAMBLE_INCAPABLE	= 1<<4,
	IEEE80211_HW_SIGNAL_UNSPEC			= 1<<5,
	IEEE80211_HW_SIGNAL_DBM				= 1<<6,
	IEEE80211_HW_NOISE_DBM				= 1<<7,
	IEEE80211_HW_SPECTRUM_MGMT			= 1<<8,
	IEEE80211_HW_AMPDU_AGGREGATION			= 1<<9,
	IEEE80211_HW_SUPPORTS_PS			= 1<<10,
	IEEE80211_HW_PS_NULLFUNC_STACK			= 1<<11,
	IEEE80211_HW_SUPPORTS_DYNAMIC_PS		= 1<<12,
	IEEE80211_HW_MFP_CAPABLE			= 1<<13,
	IEEE80211_HW_BEACON_FILTER			= 1<<14,
	IEEE80211_HW_SUPPORTS_STATIC_SMPS		= 1<<15,
	IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS		= 1<<16,
	IEEE80211_HW_SUPPORTS_UAPSD			= 1<<17,
	IEEE80211_HW_REPORTS_TX_ACK_STATUS		= 1<<18,
	IEEE80211_HW_CONNECTION_MONITOR			= 1<<19,
	IEEE80211_HW_SUPPORTS_CQM_RSSI			= 1<<20,
};

/**
 * struct ieee80211_hw - hardware information and state
 *
 * This structure contains the configuration and hardware
 * information for an 802.11 PHY.
 *
 * @wiphy: This points to the &struct wiphy allocated for this
 *	802.11 PHY. You must fill in the @perm_addr and @dev
 *	members of this structure using SET_IEEE80211_DEV()
 *	and SET_IEEE80211_PERM_ADDR(). Additionally, all supported
 *	bands (with channels, bitrates) are registered here.
 *
 * @conf: &struct ieee80211_conf, device configuration, don't use.
 *
 * @priv: pointer to private area that was allocated for driver use
 *	along with this structure.
 *
 * @flags: hardware flags, see &enum ieee80211_hw_flags.
 *
 * @extra_tx_headroom: headroom to reserve in each transmit skb
 *	for use by the driver (e.g. for transmit headers.)
 *
 * @channel_change_time: time (in microseconds) it takes to change channels.
 *
 * @max_signal: Maximum value for signal (rssi) in RX information, used
 *     only when @IEEE80211_HW_SIGNAL_UNSPEC or @IEEE80211_HW_SIGNAL_DB
 *
 * @max_listen_interval: max listen interval in units of beacon interval
 *     that HW supports
 *
 * @queues: number of available hardware transmit queues for
 *	data packets. WMM/QoS requires at least four, these
 *	queues need to have configurable access parameters.
 *
 * @rate_control_algorithm: rate control algorithm for this hardware.
 *	If unset (NULL), the default algorithm will be used. Must be
 *	set before calling ieee80211_register_hw().
 *
 * @vif_data_size: size (in bytes) of the drv_priv data area
 *	within &struct ieee80211_vif.
 * @sta_data_size: size (in bytes) of the drv_priv data area
 *	within &struct ieee80211_sta.
 *
 * @max_rates: maximum number of alternate rate retry stages
 * @max_rate_tries: maximum number of tries for each stage
 */
struct ieee80211_hw {
	struct ieee80211_conf conf;
	struct wiphy *wiphy;
	const char *rate_control_algorithm;
	void *priv;
	u32 flags;
	unsigned int extra_tx_headroom;
	int channel_change_time;
	int vif_data_size;
	int sta_data_size;
	u16 queues;
	u16 max_listen_interval;
	s8 max_signal;
	u8 max_rates;
	u8 max_rate_tries;
};

/**
 * wiphy_to_ieee80211_hw - return a mac80211 driver hw struct from a wiphy
 *
 * @wiphy: the &struct wiphy which we want to query
 *
 * mac80211 drivers can use this to get to their respective
 * &struct ieee80211_hw. Drivers wishing to get to their own private
 * structure can then access it via hw->priv. Note that mac802111 drivers should
 * not use wiphy_priv() to try to get their private driver structure as this
 * is already used internally by mac80211.
 */
struct ieee80211_hw *wiphy_to_ieee80211_hw(struct wiphy *wiphy);

/**
 * SET_IEEE80211_DEV - set device for 802.11 hardware
 *
 * @hw: the &struct ieee80211_hw to set the device for
 * @dev: the &struct device of this 802.11 device
 */
static inline void SET_IEEE80211_DEV(struct ieee80211_hw *hw, struct device *dev)
{
	set_wiphy_dev(hw->wiphy, dev);
}

/**
 * SET_IEEE80211_PERM_ADDR - set the permanent MAC address for 802.11 hardware
 *
 * @hw: the &struct ieee80211_hw to set the MAC address for
 * @addr: the address to set
 */
static inline void SET_IEEE80211_PERM_ADDR(struct ieee80211_hw *hw, u8 *addr)
{
	memcpy(hw->wiphy->perm_addr, addr, ETH_ALEN);
}

static inline struct ieee80211_rate *
ieee80211_get_tx_rate(const struct ieee80211_hw *hw,
		      const struct ieee80211_tx_info *c)
{
	if (WARN_ON(c->control.rates[0].idx < 0))
		return NULL;
	return &hw->wiphy->bands[c->band]->bitrates[c->control.rates[0].idx];
}

static inline struct ieee80211_rate *
ieee80211_get_rts_cts_rate(const struct ieee80211_hw *hw,
			   const struct ieee80211_tx_info *c)
{
	if (c->control.rts_cts_rate_idx < 0)
		return NULL;
	return &hw->wiphy->bands[c->band]->bitrates[c->control.rts_cts_rate_idx];
}

static inline struct ieee80211_rate *
ieee80211_get_alt_retry_rate(const struct ieee80211_hw *hw,
			     const struct ieee80211_tx_info *c, int idx)
{
	if (c->control.rates[idx + 1].idx < 0)
		return NULL;
	return &hw->wiphy->bands[c->band]->bitrates[c->control.rates[idx + 1].idx];
}

/**
 * DOC: Hardware crypto acceleration
 *
 * mac80211 is capable of taking advantage of many hardware
 * acceleration designs for encryption and decryption operations.
 *
 * The set_key() callback in the &struct ieee80211_ops for a given
 * device is called to enable hardware acceleration of encryption and
 * decryption. The callback takes a @sta parameter that will be NULL
 * for default keys or keys used for transmission only, or point to
 * the station information for the peer for individual keys.
 * Multiple transmission keys with the same key index may be used when
 * VLANs are configured for an access point.
 *
 * When transmitting, the TX control data will use the @hw_key_idx
 * selected by the driver by modifying the &struct ieee80211_key_conf
 * pointed to by the @key parameter to the set_key() function.
 *
 * The set_key() call for the %SET_KEY command should return 0 if
 * the key is now in use, -%EOPNOTSUPP or -%ENOSPC if it couldn't be
 * added; if you return 0 then hw_key_idx must be assigned to the
 * hardware key index, you are free to use the full u8 range.
 *
 * When the cmd is %DISABLE_KEY then it must succeed.
 *
 * Note that it is permissible to not decrypt a frame even if a key
 * for it has been uploaded to hardware, the stack will not make any
 * decision based on whether a key has been uploaded or not but rather
 * based on the receive flags.
 *
 * The &struct ieee80211_key_conf structure pointed to by the @key
 * parameter is guaranteed to be valid until another call to set_key()
 * removes it, but it can only be used as a cookie to differentiate
 * keys.
 *
 * In TKIP some HW need to be provided a phase 1 key, for RX decryption
 * acceleration (i.e. iwlwifi). Those drivers should provide update_tkip_key
 * handler.
 * The update_tkip_key() call updates the driver with the new phase 1 key.
 * This happens everytime the iv16 wraps around (every 65536 packets). The
 * set_key() call will happen only once for each key (unless the AP did
 * rekeying), it will not include a valid phase 1 key. The valid phase 1 key is
 * provided by update_tkip_key only. The trigger that makes mac80211 call this
 * handler is software decryption with wrap around of iv16.
 */

/**
 * DOC: Powersave support
 *
 * mac80211 has support for various powersave implementations.
 *
 * First, it can support hardware that handles all powersaving by itself,
 * such hardware should simply set the %IEEE80211_HW_SUPPORTS_PS hardware
 * flag. In that case, it will be told about the desired powersave mode
 * with the %IEEE80211_CONF_PS flag depending on the association status.
 * The hardware must take care of sending nullfunc frames when necessary,
 * i.e. when entering and leaving powersave mode. The hardware is required
 * to look at the AID in beacons and signal to the AP that it woke up when
 * it finds traffic directed to it.
 *
 * %IEEE80211_CONF_PS flag enabled means that the powersave mode defined in
 * IEEE 802.11-2007 section 11.2 is enabled. This is not to be confused
 * with hardware wakeup and sleep states. Driver is responsible for waking
 * up the hardware before issueing commands to the hardware and putting it
 * back to sleep at approriate times.
 *
 * When PS is enabled, hardware needs to wakeup for beacons and receive the
 * buffered multicast/broadcast frames after the beacon. Also it must be
 * possible to send frames and receive the acknowledment frame.
 *
 * Other hardware designs cannot send nullfunc frames by themselves and also
 * need software support for parsing the TIM bitmap. This is also supported
 * by mac80211 by combining the %IEEE80211_HW_SUPPORTS_PS and
 * %IEEE80211_HW_PS_NULLFUNC_STACK flags. The hardware is of course still
 * required to pass up beacons. The hardware is still required to handle
 * waking up for multicast traffic; if it cannot the driver must handle that
 * as best as it can, mac80211 is too slow to do that.
 *
 * Dynamic powersave is an extension to normal powersave in which the
 * hardware stays awake for a user-specified period of time after sending a
 * frame so that reply frames need not be buffered and therefore delayed to
 * the next wakeup. It's compromise of getting good enough latency when
 * there's data traffic and still saving significantly power in idle
 * periods.
 *
 * Dynamic powersave is supported by simply mac80211 enabling and disabling
 * PS based on traffic. Driver needs to only set %IEEE80211_HW_SUPPORTS_PS
 * flag and mac80211 will handle everything automatically. Additionally,
 * hardware having support for the dynamic PS feature may set the
 * %IEEE80211_HW_SUPPORTS_DYNAMIC_PS flag to indicate that it can support
 * dynamic PS mode itself. The driver needs to look at the
 * @dynamic_ps_timeout hardware configuration value and use it that value
 * whenever %IEEE80211_CONF_PS is set. In this case mac80211 will disable
 * dynamic PS feature in stack and will just keep %IEEE80211_CONF_PS
 * enabled whenever user has enabled powersave.
 *
 * Driver informs U-APSD client support by enabling
 * %IEEE80211_HW_SUPPORTS_UAPSD flag. The mode is configured through the
 * uapsd paramater in conf_tx() operation. Hardware needs to send the QoS
 * Nullfunc frames and stay awake until the service period has ended. To
 * utilize U-APSD, dynamic powersave is disabled for voip AC and all frames
 * from that AC are transmitted with powersave enabled.
 *
 * Note: U-APSD client mode is not yet supported with
 * %IEEE80211_HW_PS_NULLFUNC_STACK.
 */

/**
 * DOC: Beacon filter support
 *
 * Some hardware have beacon filter support to reduce host cpu wakeups
 * which will reduce system power consumption. It usuallly works so that
 * the firmware creates a checksum of the beacon but omits all constantly
 * changing elements (TSF, TIM etc). Whenever the checksum changes the
 * beacon is forwarded to the host, otherwise it will be just dropped. That
 * way the host will only receive beacons where some relevant information
 * (for example ERP protection or WMM settings) have changed.
 *
 * Beacon filter support is advertised with the %IEEE80211_HW_BEACON_FILTER
 * hardware capability. The driver needs to enable beacon filter support
 * whenever power save is enabled, that is %IEEE80211_CONF_PS is set. When
 * power save is enabled, the stack will not check for beacon loss and the
 * driver needs to notify about loss of beacons with ieee80211_beacon_loss().
 *
 * The time (or number of beacons missed) until the firmware notifies the
 * driver of a beacon loss event (which in turn causes the driver to call
 * ieee80211_beacon_loss()) should be configurable and will be controlled
 * by mac80211 and the roaming algorithm in the future.
 *
 * Since there may be constantly changing information elements that nothing
 * in the software stack cares about, we will, in the future, have mac80211
 * tell the driver which information elements are interesting in the sense
 * that we want to see changes in them. This will include
 *  - a list of information element IDs
 *  - a list of OUIs for the vendor information element
 *
 * Ideally, the hardware would filter out any beacons without changes in the
 * requested elements, but if it cannot support that it may, at the expense
 * of some efficiency, filter out only a subset. For example, if the device
 * doesn't support checking for OUIs it should pass up all changes in all
 * vendor information elements.
 *
 * Note that change, for the sake of simplification, also includes information
 * elements appearing or disappearing from the beacon.
 *
 * Some hardware supports an "ignore list" instead, just make sure nothing
 * that was requested is on the ignore list, and include commonly changing
 * information element IDs in the ignore list, for example 11 (BSS load) and
 * the various vendor-assigned IEs with unknown contents (128, 129, 133-136,
 * 149, 150, 155, 156, 173, 176, 178, 179, 219); for forward compatibility
 * it could also include some currently unused IDs.
 *
 *
 * In addition to these capabilities, hardware should support notifying the
 * host of changes in the beacon RSSI. This is relevant to implement roaming
 * when no traffic is flowing (when traffic is flowing we see the RSSI of
 * the received data packets). This can consist in notifying the host when
 * the RSSI changes significantly or when it drops below or rises above
 * configurable thresholds. In the future these thresholds will also be
 * configured by mac80211 (which gets them from userspace) to implement
 * them as the roaming algorithm requires.
 *
 * If the hardware cannot implement this, the driver should ask it to
 * periodically pass beacon frames to the host so that software can do the
 * signal strength threshold checking.
 */

/**
 * DOC: Spatial multiplexing power save
 *
 * SMPS (Spatial multiplexing power save) is a mechanism to conserve
 * power in an 802.11n implementation. For details on the mechanism
 * and rationale, please refer to 802.11 (as amended by 802.11n-2009)
 * "11.2.3 SM power save".
 *
 * The mac80211 implementation is capable of sending action frames
 * to update the AP about the station's SMPS mode, and will instruct
 * the driver to enter the specific mode. It will also announce the
 * requested SMPS mode during the association handshake. Hardware
 * support for this feature is required, and can be indicated by
 * hardware flags.
 *
 * The default mode will be "automatic", which nl80211/cfg80211
 * defines to be dynamic SMPS in (regular) powersave, and SMPS
 * turned off otherwise.
 *
 * To support this feature, the driver must set the appropriate
 * hardware support flags, and handle the SMPS flag to the config()
 * operation. It will then with this mechanism be instructed to
 * enter the requested SMPS mode while associated to an HT AP.
 */

/**
 * DOC: Frame filtering
 *
 * mac80211 requires to see many management frames for proper
 * operation, and users may want to see many more frames when
 * in monitor mode. However, for best CPU usage and power consumption,
 * having as few frames as possible percolate through the stack is
 * desirable. Hence, the hardware should filter as much as possible.
 *
 * To achieve this, mac80211 uses filter flags (see below) to tell
 * the driver's configure_filter() function which frames should be
 * passed to mac80211 and which should be filtered out.
 *
 * Before configure_filter() is invoked, the prepare_multicast()
 * callback is invoked with the parameters @mc_count and @mc_list
 * for the combined multicast address list of all virtual interfaces.
 * It's use is optional, and it returns a u64 that is passed to
 * configure_filter(). Additionally, configure_filter() has the
 * arguments @changed_flags telling which flags were changed and
 * @total_flags with the new flag states.
 *
 * If your device has no multicast address filters your driver will
 * need to check both the %FIF_ALLMULTI flag and the @mc_count
 * parameter to see whether multicast frames should be accepted
 * or dropped.
 *
 * All unsupported flags in @total_flags must be cleared.
 * Hardware does not support a flag if it is incapable of _passing_
 * the frame to the stack. Otherwise the driver must ignore
 * the flag, but not clear it.
 * You must _only_ clear the flag (announce no support for the
 * flag to mac80211) if you are not able to pass the packet type
 * to the stack (so the hardware always filters it).
 * So for example, you should clear @FIF_CONTROL, if your hardware
 * always filters control frames. If your hardware always passes
 * control frames to the kernel and is incapable of filtering them,
 * you do _not_ clear the @FIF_CONTROL flag.
 * This rule applies to all other FIF flags as well.
 */

/**
 * enum ieee80211_filter_flags - hardware filter flags
 *
 * These flags determine what the filter in hardware should be
 * programmed to let through and what should not be passed to the
 * stack. It is always safe to pass more frames than requested,
 * but this has negative impact on power consumption.
 *
 * @FIF_PROMISC_IN_BSS: promiscuous mode within your BSS,
 *	think of the BSS as your network segment and then this corresponds
 *	to the regular ethernet device promiscuous mode.
 *
 * @FIF_ALLMULTI: pass all multicast frames, this is used if requested
 *	by the user or if the hardware is not capable of filtering by
 *	multicast address.
 *
 * @FIF_FCSFAIL: pass frames with failed FCS (but you need to set the
 *	%RX_FLAG_FAILED_FCS_CRC for them)
 *
 * @FIF_PLCPFAIL: pass frames with failed PLCP CRC (but you need to set
 *	the %RX_FLAG_FAILED_PLCP_CRC for them
 *
 * @FIF_BCN_PRBRESP_PROMISC: This flag is set during scanning to indicate
 *	to the hardware that it should not filter beacons or probe responses
 *	by BSSID. Filtering them can greatly reduce the amount of processing
 *	mac80211 needs to do and the amount of CPU wakeups, so you should
 *	honour this flag if possible.
 *
 * @FIF_CONTROL: pass control frames (except for PS Poll), if PROMISC_IN_BSS
 *  is not set then only those addressed to this station.
 *
 * @FIF_OTHER_BSS: pass frames destined to other BSSes
 *
 * @FIF_PSPOLL: pass PS Poll frames, if PROMISC_IN_BSS  is not set then only
 *  those addressed to this station.
 */
enum ieee80211_filter_flags {
	FIF_PROMISC_IN_BSS	= 1<<0,
	FIF_ALLMULTI		= 1<<1,
	FIF_FCSFAIL		= 1<<2,
	FIF_PLCPFAIL		= 1<<3,
	FIF_BCN_PRBRESP_PROMISC	= 1<<4,
	FIF_CONTROL		= 1<<5,
	FIF_OTHER_BSS		= 1<<6,
	FIF_PSPOLL		= 1<<7,
};

/**
 * enum ieee80211_ampdu_mlme_action - A-MPDU actions
 *
 * These flags are used with the ampdu_action() callback in
 * &struct ieee80211_ops to indicate which action is needed.
 *
 * Note that drivers MUST be able to deal with a TX aggregation
 * session being stopped even before they OK'ed starting it by
 * calling ieee80211_start_tx_ba_cb(_irqsafe), because the peer
 * might receive the addBA frame and send a delBA right away!
 *
 * @IEEE80211_AMPDU_RX_START: start Rx aggregation
 * @IEEE80211_AMPDU_RX_STOP: stop Rx aggregation
 * @IEEE80211_AMPDU_TX_START: start Tx aggregation
 * @IEEE80211_AMPDU_TX_STOP: stop Tx aggregation
 * @IEEE80211_AMPDU_TX_OPERATIONAL: TX aggregation has become operational
 */
enum ieee80211_ampdu_mlme_action {
	IEEE80211_AMPDU_RX_START,
	IEEE80211_AMPDU_RX_STOP,
	IEEE80211_AMPDU_TX_START,
	IEEE80211_AMPDU_TX_STOP,
	IEEE80211_AMPDU_TX_OPERATIONAL,
};

/**
 * 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. This handler should,
 *	preferably, never fail and stop queues appropriately, more
 *	importantly, however, it must never fail for A-MPDU-queues.
 *	This function should return NETDEV_TX_OK except in very
 *	limited cases.
 *	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 and can sleep.
 *
 * @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. If you added any work onto the mac80211 workqueue
 *	you should ensure to cancel it on this callback.
 *	Must be implemented and can sleep.
 *
 * @add_interface: Called when a netdevice attached to the hardware is