mac80211.h

/*
 * 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/bug.h>
#include <linux/kernel.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/ieee80211.h>
#include <net/cfg80211.h>
#include <asm/unaligned.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.
 *
 */

struct device;

/**
 * enum ieee80211_max_queues - maximum number of queues
 *
 * @IEEE80211_MAX_QUEUES: Maximum number of regular device queues.
 */
enum ieee80211_max_queues {
	IEEE80211_MAX_QUEUES =		16,
};

#define IEEE80211_INVAL_HW_QUEUE	0xff

/**
 * enum ieee80211_ac_numbers - AC numbers as used in mac80211
 * @IEEE80211_AC_VO: voice
 * @IEEE80211_AC_VI: video
 * @IEEE80211_AC_BE: best effort
 * @IEEE80211_AC_BK: background
 */
enum ieee80211_ac_numbers {
	IEEE80211_AC_VO		= 0,
	IEEE80211_AC_VI		= 1,
	IEEE80211_AC_BE		= 2,
	IEEE80211_AC_BK		= 3,
};
#define IEEE80211_NUM_ACS	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_chanctx_change - change flag for channel context
 * @IEEE80211_CHANCTX_CHANGE_WIDTH: The channel width changed
 * @IEEE80211_CHANCTX_CHANGE_RX_CHAINS: The number of RX chains changed
 */
enum ieee80211_chanctx_change {
	IEEE80211_CHANCTX_CHANGE_WIDTH		= BIT(0),
	IEEE80211_CHANCTX_CHANGE_RX_CHAINS	= BIT(1),
};

/**
 * struct ieee80211_chanctx_conf - channel context that vifs may be tuned to
 *
 * This is the driver-visible part. The ieee80211_chanctx
 * that contains it is visible in mac80211 only.
 *
 * @def: the channel definition
 * @rx_chains_static: The number of RX chains that must always be
 *	active on the channel to receive MIMO transmissions
 * @rx_chains_dynamic: The number of RX chains that must be enabled
 *	after RTS/CTS handshake to receive SMPS MIMO transmissions;
 *	this will always be >= @rx_chains_static.
 * @drv_priv: data area for driver use, will always be aligned to
 *	sizeof(void *), size is determined in hw information.
 */
struct ieee80211_chanctx_conf {
	struct cfg80211_chan_def def;

	u8 rx_chains_static, rx_chains_dynamic;

	u8 drv_priv[0] __aligned(sizeof(void *));
};

/**
 * 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
 * @BSS_CHANGED_IBSS: IBSS join status changed
 * @BSS_CHANGED_ARP_FILTER: Hardware ARP filter address list or state changed.
 * @BSS_CHANGED_QOS: QoS for this association was enabled/disabled. Note
 *	that it is only ever disabled for station mode.
 * @BSS_CHANGED_IDLE: Idle changed for this BSS/interface.
 * @BSS_CHANGED_SSID: SSID changed for this BSS (AP mode)
 * @BSS_CHANGED_AP_PROBE_RESP: Probe Response changed for this BSS (AP mode)
 * @BSS_CHANGED_PS: PS changed for this BSS (STA mode)
 * @BSS_CHANGED_TXPOWER: TX power setting changed for this interface
 * @BSS_CHANGED_P2P_PS: P2P powersave settings (CTWindow, opportunistic PS)
 *	changed (currently only in P2P client mode, GO mode will be later)
 */
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,
	BSS_CHANGED_IBSS		= 1<<11,
	BSS_CHANGED_ARP_FILTER		= 1<<12,
	BSS_CHANGED_QOS			= 1<<13,
	BSS_CHANGED_IDLE		= 1<<14,
	BSS_CHANGED_SSID		= 1<<15,
	BSS_CHANGED_AP_PROBE_RESP	= 1<<16,
	BSS_CHANGED_PS			= 1<<17,
	BSS_CHANGED_TXPOWER		= 1<<18,
	BSS_CHANGED_P2P_PS		= 1<<19,

	/* when adding here, make sure to change ieee80211_reconfig */
};

/*
 * The maximum number of IPv4 addresses listed for ARP filtering. If the number
 * of addresses for an interface increase beyond this value, hardware ARP
 * filtering will be disabled.
 */
#define IEEE80211_BSS_ARP_ADDR_LIST_LEN 4

/**
 * enum ieee80211_rssi_event - RSSI threshold event
 * An indicator for when RSSI goes below/above a certain threshold.
 * @RSSI_EVENT_HIGH: AP's rssi crossed the high threshold set by the driver.
 * @RSSI_EVENT_LOW: AP's rssi crossed the low threshold set by the driver.
 */
enum ieee80211_rssi_event {
	RSSI_EVENT_HIGH,
	RSSI_EVENT_LOW,
};

/**
 * 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
 * @ibss_joined: indicates whether this station is part of an IBSS
 *	or not
 * @ibss_creator: indicates if a new IBSS network is being created
 * @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,
 *	valid in station mode only while @assoc is true and if also
 *	requested by %IEEE80211_HW_NEED_DTIM_PERIOD (cf. also hw conf
 *	@ps_dtim_period)
 * @sync_tsf: last beacon's/probe response's TSF timestamp (could be old
 *	as it may have been received during scanning long ago)
 * @sync_device_ts: the device timestamp corresponding to the sync_tsf,
 *	the driver/device can use this to calculate synchronisation
 * @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.
 * @mcast_rate: per-band multicast rate index + 1 (0: disabled)
 * @bssid: The BSSID for this BSS
 * @enable_beacon: whether beaconing should be enabled or not
 * @chandef: Channel definition for this BSS -- the hardware might be
 *	configured a higher bandwidth than this BSS uses, for example.
 * @ht_operation_mode: HT operation mode like in &struct ieee80211_ht_operation.
 *	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
 * @arp_addr_list: List of IPv4 addresses for hardware ARP filtering. The
 *	may filter ARP queries targeted for other addresses than listed here.
 *	The driver must allow ARP queries targeted for all address listed here
 *	to pass through. An empty list implies no ARP queries need to pass.
 * @arp_addr_cnt: Number of addresses currently on the list. Note that this
 *	may be larger than %IEEE80211_BSS_ARP_ADDR_LIST_LEN (the arp_addr_list
 *	array size), it's up to the driver what to do in that case.
 * @qos: This is a QoS-enabled BSS.
 * @idle: This interface is idle. There's also a global idle flag in the
 *	hardware config which may be more appropriate depending on what
 *	your driver/device needs to do.
 * @ps: power-save mode (STA only). This flag is NOT affected by
 *	offchannel/dynamic_ps operations.
 * @ssid: The SSID of the current vif. Only valid in AP-mode.
 * @ssid_len: Length of SSID given in @ssid.
 * @hidden_ssid: The SSID of the current vif is hidden. Only valid in AP-mode.
 * @txpower: TX power in dBm
 * @p2p_ctwindow: P2P CTWindow, only for P2P client interfaces
 * @p2p_oppps: P2P opportunistic PS is enabled
 */
struct ieee80211_bss_conf {
	const u8 *bssid;
	/* association related data */
	bool assoc, ibss_joined;
	bool ibss_creator;
	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 sync_tsf;
	u32 sync_device_ts;
	u32 basic_rates;
	int mcast_rate[IEEE80211_NUM_BANDS];
	u16 ht_operation_mode;
	s32 cqm_rssi_thold;
	u32 cqm_rssi_hyst;
	struct cfg80211_chan_def chandef;
	__be32 arp_addr_list[IEEE80211_BSS_ARP_ADDR_LIST_LEN];
	int arp_addr_cnt;
	bool qos;
	bool idle;
	bool ps;
	u8 ssid[IEEE80211_MAX_SSID_LEN];
	size_t ssid_len;
	bool hidden_ssid;
	int txpower;
	u8 p2p_ctwindow;
	bool p2p_oppps;
};

/**
 * 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_NO_PS_BUFFER: This frame is a response to a poll
 *	frame (PS-Poll or uAPSD) or a non-bufferable MMPDU and must
 *	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_NL80211_FRAME_TX: Frame was requested through nl80211
 *	MLME command (internal to mac80211 to figure out whether to send TX
 *	status to user space)
 * @IEEE80211_TX_CTL_LDPC: tells the driver to use LDPC for this frame
 * @IEEE80211_TX_CTL_STBC: Enables Space-Time Block Coding (STBC) for this
 *	frame and selects the maximum number of streams that it can use.
 * @IEEE80211_TX_CTL_TX_OFFCHAN: Marks this packet to be transmitted on
 *	the off-channel channel when a remain-on-channel offload is done
 *	in hardware -- normal packets still flow and are expected to be
 *	handled properly by the device.
 * @IEEE80211_TX_INTFL_TKIP_MIC_FAILURE: Marks this packet to be used for TKIP
 *	testing. It will be sent out with incorrect Michael MIC key to allow
 *	TKIP countermeasures to be tested.
 * @IEEE80211_TX_CTL_NO_CCK_RATE: This frame will be sent at non CCK rate.
 *	This flag is actually used for management frame especially for P2P
 *	frames not being sent at CCK rate in 2GHz band.
 * @IEEE80211_TX_STATUS_EOSP: This packet marks the end of service period,
 *	when its status is reported the service period ends. For frames in
 *	an SP that mac80211 transmits, it is already set; for driver frames
 *	the driver may set this flag. It is also used to do the same for
 *	PS-Poll responses.
 * @IEEE80211_TX_CTL_USE_MINRATE: This frame will be sent at lowest rate.
 *	This flag is used to send nullfunc frame at minimum rate when
 *	the nullfunc is used for connection monitoring purpose.
 * @IEEE80211_TX_CTL_DONTFRAG: Don't fragment this packet even if it
 *	would be fragmented by size (this is optional, only used for
 *	monitor injection).
 *
 * Note: If you have to add new flags to the enumeration, then don't
 *	 forget to update %IEEE80211_TX_TEMPORARY_FLAGS when necessary.
 */
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_NO_PS_BUFFER		= BIT(17),
	IEEE80211_TX_CTL_MORE_FRAMES		= BIT(18),
	IEEE80211_TX_INTFL_RETRANSMISSION	= BIT(19),
	/* hole at 20, use later */
	IEEE80211_TX_INTFL_NL80211_FRAME_TX	= BIT(21),
	IEEE80211_TX_CTL_LDPC			= BIT(22),
	IEEE80211_TX_CTL_STBC			= BIT(23) | BIT(24),
	IEEE80211_TX_CTL_TX_OFFCHAN		= BIT(25),
	IEEE80211_TX_INTFL_TKIP_MIC_FAILURE	= BIT(26),
	IEEE80211_TX_CTL_NO_CCK_RATE		= BIT(27),
	IEEE80211_TX_STATUS_EOSP		= BIT(28),
	IEEE80211_TX_CTL_USE_MINRATE		= BIT(29),
	IEEE80211_TX_CTL_DONTFRAG		= BIT(30),
};

#define IEEE80211_TX_CTL_STBC_SHIFT		23

/*
 * This definition is used as a mask to clear all temporary flags, which are
 * set by the tx handlers for each transmission attempt by the mac80211 stack.
 */
#define IEEE80211_TX_TEMPORARY_FLAGS (IEEE80211_TX_CTL_NO_ACK |		      \
	IEEE80211_TX_CTL_CLEAR_PS_FILT | IEEE80211_TX_CTL_FIRST_FRAGMENT |    \
	IEEE80211_TX_CTL_SEND_AFTER_DTIM | IEEE80211_TX_CTL_AMPDU |	      \
	IEEE80211_TX_STAT_TX_FILTERED |	IEEE80211_TX_STAT_ACK |		      \
	IEEE80211_TX_STAT_AMPDU | IEEE80211_TX_STAT_AMPDU_NO_BACK |	      \
	IEEE80211_TX_CTL_RATE_CTRL_PROBE | IEEE80211_TX_CTL_NO_PS_BUFFER |    \
	IEEE80211_TX_CTL_MORE_FRAMES | IEEE80211_TX_CTL_LDPC |		      \
	IEEE80211_TX_CTL_STBC | IEEE80211_TX_STATUS_EOSP)

/**
 * 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_VHT_MCS: VHT MCS rate, in this case the idx field is split
 *	into a higher 4 bits (Nss) and lower 4 bits (MCS number)
 * @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_80_MHZ_WIDTH: Indicates 80 MHz transmission
 * @IEEE80211_TX_RC_160_MHZ_WIDTH: Indicates 160 MHz transmission
 *	(80+80 isn't supported yet)
 * @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 HT/VHT MCS 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),
	IEEE80211_TX_RC_VHT_MCS			= BIT(8),
	IEEE80211_TX_RC_80_MHZ_WIDTH		= BIT(9),
	IEEE80211_TX_RC_160_MHZ_WIDTH		= BIT(10),
};


/* 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	4

/**
 * 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;
	u16 count:5,
	    flags:11;
} __packed;

#define IEEE80211_MAX_TX_RETRY		31

static inline void ieee80211_rate_set_vht(struct ieee80211_tx_rate *rate,
					  u8 mcs, u8 nss)
{
	WARN_ON(mcs & ~0xF);
	WARN_ON(nss & ~0x7);
	rate->idx = (nss << 4) | mcs;
}

static inline u8
ieee80211_rate_get_vht_mcs(const struct ieee80211_tx_rate *rate)
{
	return rate->idx & 0xF;
}

static inline u8
ieee80211_rate_get_vht_nss(const struct ieee80211_tx_rate *rate)
{
	return rate->idx >> 4;
}

/**
 * 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
 *
 * @flags: transmit info flags, defined above
 * @band: the band to transmit on (use for checking for races)
 * @hw_queue: HW queue to put the frame on, skb_get_queue_mapping() gives the AC
 * @ack_frame_id: internal frame ID for TX status, used internally
 * @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_STAT_AMPDU was set.
 * @ampdu_len: number of aggregated frames.
 * 	relevant only if IEEE80211_TX_STAT_AMPDU was set.
 * @ack_signal: signal strength of the ACK frame
 */
struct ieee80211_tx_info {
	/* common information */
	u32 flags;
	u8 band;

	u8 hw_queue;

	u16 ack_frame_id;

	union {
		struct {
			union {
				/* rate control */
				struct {
					struct ieee80211_tx_rate rates[
						IEEE80211_TX_MAX_RATES];
					s8 rts_cts_rate_idx;
					/* 3 bytes free */
				};
				/* 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;
			/* 8 bytes free */
		} control;
		struct {
			struct ieee80211_tx_rate rates[IEEE80211_TX_MAX_RATES];
			int ack_signal;
			u8 ampdu_ack_len;
			u8 ampdu_len;
			u8 antenna;
			/* 21 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 *)];
	};
};

/**
 * struct ieee80211_sched_scan_ies - scheduled scan IEs
 *
 * This structure is used to pass the appropriate IEs to be used in scheduled
 * scans for all bands.  It contains both the IEs passed from the userspace
 * and the ones generated by mac80211.
 *
 * @ie: array with the IEs for each supported band
 * @len: array with the total length of the IEs for each band
 */
struct ieee80211_sched_scan_ies {
	u8 *ie[IEEE80211_NUM_BANDS];
	size_t len[IEEE80211_NUM_BANDS];
};

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.ack_signal) != 20);
	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_MACTIME_START: The timestamp passed in the RX status (@mactime
 *	field) is valid and contains the time the first symbol of the MPDU
 *	was received. This is useful in monitor mode and for proper IBSS
 *	merging.
 * @RX_FLAG_MACTIME_END: The timestamp passed in the RX status (@mactime
 *	field) is valid and contains the time the last symbol of the MPDU
 *	(including FCS) was received.
 * @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_VHT: VHT MCS was used and rate_index is MCS index
 * @RX_FLAG_40MHZ: HT40 (40 MHz) was used
 * @RX_FLAG_80MHZ: 80 MHz was used
 * @RX_FLAG_80P80MHZ: 80+80 MHz was used
 * @RX_FLAG_160MHZ: 160 MHz was used
 * @RX_FLAG_SHORT_GI: Short guard interval was used
 * @RX_FLAG_NO_SIGNAL_VAL: The signal strength value is not present.
 *	Valid only for data frames (mainly A-MPDU)
 * @RX_FLAG_HT_GF: This frame was received in a HT-greenfield transmission, if
 *	the driver fills this value it should add %IEEE80211_RADIOTAP_MCS_HAVE_FMT
 *	to hw.radiotap_mcs_details to advertise that fact
 * @RX_FLAG_AMPDU_DETAILS: A-MPDU details are known, in particular the reference
 *	number (@ampdu_reference) must be populated and be a distinct number for
 *	each A-MPDU
 * @RX_FLAG_AMPDU_REPORT_ZEROLEN: driver reports 0-length subframes
 * @RX_FLAG_AMPDU_IS_ZEROLEN: This is a zero-length subframe, for
 *	monitoring purposes only
 * @RX_FLAG_AMPDU_LAST_KNOWN: last subframe is known, should be set on all
 *	subframes of a single A-MPDU
 * @RX_FLAG_AMPDU_IS_LAST: this subframe is the last subframe of the A-MPDU
 * @RX_FLAG_AMPDU_DELIM_CRC_ERROR: A delimiter CRC error has been detected
 *	on this subframe
 * @RX_FLAG_AMPDU_DELIM_CRC_KNOWN: The delimiter CRC field is known (the CRC
 *	is stored in the @ampdu_delimiter_crc field)
 */
enum mac80211_rx_flags {
	RX_FLAG_MMIC_ERROR		= BIT(0),
	RX_FLAG_DECRYPTED		= BIT(1),
	RX_FLAG_MMIC_STRIPPED		= BIT(3),
	RX_FLAG_IV_STRIPPED		= BIT(4),
	RX_FLAG_FAILED_FCS_CRC		= BIT(5),
	RX_FLAG_FAILED_PLCP_CRC 	= BIT(6),
	RX_FLAG_MACTIME_START		= BIT(7),
	RX_FLAG_SHORTPRE		= BIT(8),
	RX_FLAG_HT			= BIT(9),
	RX_FLAG_40MHZ			= BIT(10),
	RX_FLAG_SHORT_GI		= BIT(11),
	RX_FLAG_NO_SIGNAL_VAL		= BIT(12),
	RX_FLAG_HT_GF			= BIT(13),
	RX_FLAG_AMPDU_DETAILS		= BIT(14),
	RX_FLAG_AMPDU_REPORT_ZEROLEN	= BIT(15),
	RX_FLAG_AMPDU_IS_ZEROLEN	= BIT(16),
	RX_FLAG_AMPDU_LAST_KNOWN	= BIT(17),
	RX_FLAG_AMPDU_IS_LAST		= BIT(18),
	RX_FLAG_AMPDU_DELIM_CRC_ERROR	= BIT(19),
	RX_FLAG_AMPDU_DELIM_CRC_KNOWN	= BIT(20),
	RX_FLAG_MACTIME_END		= BIT(21),
	RX_FLAG_VHT			= BIT(22),
	RX_FLAG_80MHZ			= BIT(23),
	RX_FLAG_80P80MHZ		= BIT(24),
	RX_FLAG_160MHZ			= BIT(25),
};

/**
 * 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.
 * @device_timestamp: arbitrary timestamp for the device, mac80211 doesn't use
 *	it but can store it and pass it back to the driver for synchronisation
 * @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_*
 * @antenna: antenna used
 * @rate_idx: index of data rate into band's supported rates or MCS index if
 *	HT or VHT is used (%RX_FLAG_HT/%RX_FLAG_VHT)
 * @vht_nss: number of streams (VHT only)
 * @flag: %RX_FLAG_*
 * @rx_flags: internal RX flags for mac80211
 * @ampdu_reference: A-MPDU reference number, must be a different value for
 *	each A-MPDU but the same for each subframe within one A-MPDU
 * @ampdu_delimiter_crc: A-MPDU delimiter CRC
 * @vendor_radiotap_bitmap: radiotap vendor namespace presence bitmap
 * @vendor_radiotap_len: radiotap vendor namespace length
 * @vendor_radiotap_align: radiotap vendor namespace alignment. Note
 *	that the actual data must be at the start of the SKB data
 *	already.
 * @vendor_radiotap_oui: radiotap vendor namespace OUI
 * @vendor_radiotap_subns: radiotap vendor sub namespace
 */
struct ieee80211_rx_status {
	u64 mactime;
	u32 device_timestamp;
	u32 ampdu_reference;
	u32 flag;
	u32 vendor_radiotap_bitmap;
	u16 vendor_radiotap_len;
	u16 freq;
	u8 rate_idx;
	u8 vht_nss;
	u8 rx_flags;
	u8 band;
	u8 antenna;
	s8 signal;
	u8 ampdu_delimiter_crc;
	u8 vendor_radiotap_align;
	u8 vendor_radiotap_oui[3];
	u8 vendor_radiotap_subns;
};

/**
 * 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_OFFCHANNEL: The device is currently not on its main
 *	operating channel.
 */
enum ieee80211_conf_flags {
	IEEE80211_CONF_MONITOR		= (1<<0),
	IEEE80211_CONF_PS		= (1<<1),
	IEEE80211_CONF_IDLE		= (1<<2),
	IEEE80211_CONF_OFFCHANNEL	= (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
 *	Note that this is only valid if channel contexts are not used,
 *	otherwise each channel context has the number of chains listed.
 */
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),
};

/**
 * 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), backward compatibility
 *	value only that is set to the minimum of all interfaces
 *
 * @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.
 *	Note that this is only valid if channel contexts are not used,
 *	otherwise each channel context has the number of chains listed.
 */
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;