/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * 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>
 * Copyright 2013-2014  Intel Mobile Communications GmbH
 * Copyright (C) 2015 - 2017 Intel Deutschland GmbH
 * Copyright (C) 2018 - 2020 Intel Corporation
 */

#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 <net/codel.h>
#include <net/ieee80211_radiotap.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.
 */

/**
 * 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.
 *
 */

/**
 * DOC: mac80211 software tx queueing
 *
 * mac80211 provides an optional intermediate queueing implementation designed
 * to allow the driver to keep hardware queues short and provide some fairness
 * between different stations/interfaces.
 * In this model, the driver pulls data frames from the mac80211 queue instead
 * of letting mac80211 push them via drv_tx().
 * Other frames (e.g. control or management) are still pushed using drv_tx().
 *
 * Drivers indicate that they use this model by implementing the .wake_tx_queue
 * driver operation.
 *
 * Intermediate queues (struct ieee80211_txq) are kept per-sta per-tid, with
 * another per-sta for non-data/non-mgmt and bufferable management frames, and
 * a single per-vif queue for multicast data frames.
 *
 * The driver is expected to initialize its private per-queue data for stations
 * and interfaces in the .add_interface and .sta_add ops.
 *
 * The driver can't access the queue directly. To dequeue a frame from a
 * txq, it calls ieee80211_tx_dequeue(). Whenever mac80211 adds a new frame to a
 * queue, it calls the .wake_tx_queue driver op.
 *
 * Drivers can optionally delegate responsibility for scheduling queues to
 * mac80211, to take advantage of airtime fairness accounting. In this case, to
 * obtain the next queue to pull frames from, the driver calls
 * ieee80211_next_txq(). The driver is then expected to return the txq using
 * ieee80211_return_txq().
 *
 * For AP powersave TIM handling, the driver only needs to indicate if it has
 * buffered packets in the driver specific data structures by calling
 * ieee80211_sta_set_buffered(). For frames buffered in the ieee80211_txq
 * struct, mac80211 sets the appropriate TIM PVB bits and calls
 * .release_buffered_frames().
 * In that callback the driver is therefore expected to release its own
 * buffered frames and afterwards also frames from the ieee80211_txq (obtained
 * via the usual ieee80211_tx_dequeue).
 */

struct device;

/**
 * enum ieee80211_max_queues - maximum number of queues
 *
 * @IEEE80211_MAX_QUEUES: Maximum number of regular device queues.
 * @IEEE80211_MAX_QUEUE_MAP: bitmap with maximum queues set
 */
enum ieee80211_max_queues {
        IEEE80211_MAX_QUEUES =          16,
        IEEE80211_MAX_QUEUE_MAP =       BIT(IEEE80211_MAX_QUEUES) - 1,
};

#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,
};

/**
 * 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
 * @acm: is mandatory admission control required for the access category
 * @uapsd: is U-APSD mode enabled for the queue
 * @mu_edca: is the MU EDCA configured
 * @mu_edca_param_rec: MU EDCA Parameter Record for HE
 */
struct ieee80211_tx_queue_params {
        u16 txop;
        u16 cw_min;
        u16 cw_max;
        u8 aifs;
        bool acm;
        bool uapsd;
        bool mu_edca;
        struct ieee80211_he_mu_edca_param_ac_rec mu_edca_param_rec;
};

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
 * @IEEE80211_CHANCTX_CHANGE_RADAR: radar detection flag changed
 * @IEEE80211_CHANCTX_CHANGE_CHANNEL: switched to another operating channel,
 *      this is used only with channel switching with CSA
 * @IEEE80211_CHANCTX_CHANGE_MIN_WIDTH: The min required channel width changed
 */
enum ieee80211_chanctx_change {
        IEEE80211_CHANCTX_CHANGE_WIDTH          = BIT(0),
        IEEE80211_CHANCTX_CHANGE_RX_CHAINS      = BIT(1),
        IEEE80211_CHANCTX_CHANGE_RADAR          = BIT(2),
        IEEE80211_CHANCTX_CHANGE_CHANNEL        = BIT(3),
        IEEE80211_CHANCTX_CHANGE_MIN_WIDTH      = BIT(4),
};

/**
 * 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
 * @min_def: the minimum channel definition currently required.
 * @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.
 * @radar_enabled: whether radar detection is enabled on this channel.
 * @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;
        struct cfg80211_chan_def min_def;

        u8 rx_chains_static, rx_chains_dynamic;

        bool radar_enabled;

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

/**
 * enum ieee80211_chanctx_switch_mode - channel context switch mode
 * @CHANCTX_SWMODE_REASSIGN_VIF: Both old and new contexts already
 *      exist (and will continue to exist), but the virtual interface
 *      needs to be switched from one to the other.
 * @CHANCTX_SWMODE_SWAP_CONTEXTS: The old context exists but will stop
 *      to exist with this call, the new context doesn't exist but
 *      will be active after this call, the virtual interface switches
 *      from the old to the new (note that the driver may of course
 *      implement this as an on-the-fly chandef switch of the existing
 *      hardware context, but the mac80211 pointer for the old context
 *      will cease to exist and only the new one will later be used
 *      for changes/removal.)
 */
enum ieee80211_chanctx_switch_mode {
        CHANCTX_SWMODE_REASSIGN_VIF,
        CHANCTX_SWMODE_SWAP_CONTEXTS,
};

/**
 * struct ieee80211_vif_chanctx_switch - vif chanctx switch information
 *
 * This is structure is used to pass information about a vif that
 * needs to switch from one chanctx to another.  The
 * &ieee80211_chanctx_switch_mode defines how the switch should be
 * done.
 *
 * @vif: the vif that should be switched from old_ctx to new_ctx
 * @old_ctx: the old context to which the vif was assigned
 * @new_ctx: the new context to which the vif must be assigned
 */
struct ieee80211_vif_chanctx_switch {
        struct ieee80211_vif *vif;
        struct ieee80211_chanctx_conf *old_ctx;
        struct ieee80211_chanctx_conf *new_ctx;
};

/**
 * 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 and IBSS 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
 * @BSS_CHANGED_BEACON_INFO: Data from the AP's beacon became available:
 *      currently dtim_period only is under consideration.
 * @BSS_CHANGED_BANDWIDTH: The bandwidth used by this interface changed,
 *      note that this is only called when it changes after the channel
 *      context had been assigned.
 * @BSS_CHANGED_OCB: OCB join status changed
 * @BSS_CHANGED_MU_GROUPS: VHT MU-MIMO group id or user position changed
 * @BSS_CHANGED_KEEP_ALIVE: keep alive options (idle period or protected
 *      keep alive) changed.
 * @BSS_CHANGED_MCAST_RATE: Multicast Rate setting changed for this interface
 * @BSS_CHANGED_FTM_RESPONDER: fine timing measurement request responder
 *      functionality changed for this BSS (AP mode).
 * @BSS_CHANGED_TWT: TWT status changed
 * @BSS_CHANGED_HE_OBSS_PD: OBSS Packet Detection status changed.
 * @BSS_CHANGED_HE_BSS_COLOR: BSS Color has 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,
        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,
        BSS_CHANGED_BEACON_INFO         = 1<<20,
        BSS_CHANGED_BANDWIDTH           = 1<<21,
        BSS_CHANGED_OCB                 = 1<<22,
        BSS_CHANGED_MU_GROUPS           = 1<<23,
        BSS_CHANGED_KEEP_ALIVE          = 1<<24,
        BSS_CHANGED_MCAST_RATE          = 1<<25,
        BSS_CHANGED_FTM_RESPONDER       = 1<<26,
        BSS_CHANGED_TWT                 = 1<<27,
        BSS_CHANGED_HE_OBSS_PD          = 1<<28,
        BSS_CHANGED_HE_BSS_COLOR        = 1<<29,

        /* 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_event_type - event to be notified to the low level driver
 * @RSSI_EVENT: AP's rssi crossed the a threshold set by the driver.
 * @MLME_EVENT: event related to MLME
 * @BAR_RX_EVENT: a BAR was received
 * @BA_FRAME_TIMEOUT: Frames were released from the reordering buffer because
 *      they timed out. This won't be called for each frame released, but only
 *      once each time the timeout triggers.
 */
enum ieee80211_event_type {
        RSSI_EVENT,
        MLME_EVENT,
        BAR_RX_EVENT,
        BA_FRAME_TIMEOUT,
};

/**
 * enum ieee80211_rssi_event_data - relevant when event type is %RSSI_EVENT
 * @RSSI_EVENT_HIGH: AP's rssi went below the threshold set by the driver.
 * @RSSI_EVENT_LOW: AP's rssi went above the threshold set by the driver.
 */
enum ieee80211_rssi_event_data {
        RSSI_EVENT_HIGH,
        RSSI_EVENT_LOW,
};

/**
 * struct ieee80211_rssi_event - data attached to an %RSSI_EVENT
 * @data: See &enum ieee80211_rssi_event_data
 */
struct ieee80211_rssi_event {
        enum ieee80211_rssi_event_data data;
};

/**
 * enum ieee80211_mlme_event_data - relevant when event type is %MLME_EVENT
 * @AUTH_EVENT: the MLME operation is authentication
 * @ASSOC_EVENT: the MLME operation is association
 * @DEAUTH_RX_EVENT: deauth received..
 * @DEAUTH_TX_EVENT: deauth sent.
 */
enum ieee80211_mlme_event_data {
        AUTH_EVENT,
        ASSOC_EVENT,
        DEAUTH_RX_EVENT,
        DEAUTH_TX_EVENT,
};

/**
 * enum ieee80211_mlme_event_status - relevant when event type is %MLME_EVENT
 * @MLME_SUCCESS: the MLME operation completed successfully.
 * @MLME_DENIED: the MLME operation was denied by the peer.
 * @MLME_TIMEOUT: the MLME operation timed out.
 */
enum ieee80211_mlme_event_status {
        MLME_SUCCESS,
        MLME_DENIED,
        MLME_TIMEOUT,
};

/**
 * struct ieee80211_mlme_event - data attached to an %MLME_EVENT
 * @data: See &enum ieee80211_mlme_event_data
 * @status: See &enum ieee80211_mlme_event_status
 * @reason: the reason code if applicable
 */
struct ieee80211_mlme_event {
        enum ieee80211_mlme_event_data data;
        enum ieee80211_mlme_event_status status;
        u16 reason;
};

/**
 * struct ieee80211_ba_event - data attached for BlockAck related events
 * @sta: pointer to the &ieee80211_sta to which this event relates
 * @tid: the tid
 * @ssn: the starting sequence number (for %BAR_RX_EVENT)
 */
struct ieee80211_ba_event {
        struct ieee80211_sta *sta;
        u16 tid;
        u16 ssn;
};

/**
 * struct ieee80211_event - event to be sent to the driver
 * @type: The event itself. See &enum ieee80211_event_type.
 * @rssi: relevant if &type is %RSSI_EVENT
 * @mlme: relevant if &type is %AUTH_EVENT
 * @ba: relevant if &type is %BAR_RX_EVENT or %BA_FRAME_TIMEOUT
 * @u:union holding the fields above
 */
struct ieee80211_event {
        enum ieee80211_event_type type;
        union {
                struct ieee80211_rssi_event rssi;
                struct ieee80211_mlme_event mlme;
                struct ieee80211_ba_event ba;
        } u;
};

/**
 * struct ieee80211_mu_group_data - STA's VHT MU-MIMO group data
 *
 * This structure describes the group id data of VHT MU-MIMO
 *
 * @membership: 64 bits array - a bit is set if station is member of the group
 * @position: 2 bits per group id indicating the position in the group
 */
struct ieee80211_mu_group_data {
        u8 membership[WLAN_MEMBERSHIP_LEN];
        u8 position[WLAN_USER_POSITION_LEN];
};

/**
 * struct ieee80211_ftm_responder_params - FTM responder parameters
 *
 * @lci: LCI subelement content
 * @civicloc: CIVIC location subelement content
 * @lci_len: LCI data length
 * @civicloc_len: Civic data length
 */
struct ieee80211_ftm_responder_params {
        const u8 *lci;
        const u8 *civicloc;
        size_t lci_len;
        size_t civicloc_len;
};

/**
 * 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.
 *
 * @htc_trig_based_pkt_ext: default PE in 4us units, if BSS supports HE
 * @multi_sta_back_32bit: supports BA bitmap of 32-bits in Multi-STA BACK
 * @uora_exists: is the UORA element advertised by AP
 * @ack_enabled: indicates support to receive a multi-TID that solicits either
 *      ACK, BACK or both
 * @uora_ocw_range: UORA element's OCW Range field
 * @frame_time_rts_th: HE duration RTS threshold, in units of 32us
 * @he_support: does this BSS support HE
 * @twt_requester: does this BSS support TWT requester (relevant for managed
 *      mode only, set if the AP advertises TWT responder role)
 * @twt_responder: does this BSS support TWT requester (relevant for managed
 *      mode only, set if the AP advertises TWT responder role)
 * @twt_protected: does this BSS support protected TWT frames
 * @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
 * @use_short_slot: use short slot time (only relevant for ERP)
 * @dtim_period: num of beacons before the next DTIM, for beaconing,
 *      valid in station mode only if after the driver was notified
 *      with the %BSS_CHANGED_BEACON_INFO flag, will be non-zero then.
 * @sync_tsf: last beacon's/probe response's TSF timestamp (could be old
 *      as it may have been received during scanning long ago). If the
 *      HW flag %IEEE80211_HW_TIMING_BEACON_ONLY is set, then this can
 *      only come from a beacon, but might not become valid until after
 *      association when a beacon is received (which is notified with the
 *      %BSS_CHANGED_DTIM flag.). See also sync_dtim_count important notice.
 * @sync_device_ts: the device timestamp corresponding to the sync_tsf,
 *      the driver/device can use this to calculate synchronisation
 *      (see @sync_tsf). See also sync_dtim_count important notice.
 * @sync_dtim_count: Only valid when %IEEE80211_HW_TIMING_BEACON_ONLY
 *      is requested, see @sync_tsf/@sync_device_ts.
 *      IMPORTANT: These three sync_* parameters would possibly be out of sync
 *      by the time the driver will use them. The synchronized view is currently
 *      guaranteed only in certain callbacks.
 * @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.
 * @beacon_rate: associated AP's beacon TX rate
 * @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.
 * @mu_group: VHT MU-MIMO group membership data
 * @ht_operation_mode: HT operation mode like in &struct ieee80211_ht_operation.
 *      This field is only valid when the channel is a wide HT/VHT channel.
 *      Note that with TDLS this can be the case (channel is HT, protection must
 *      be used from this field) even when the BSS association isn't using HT.
 * @cqm_rssi_thold: Connection quality monitor RSSI threshold, a zero value
 *      implies disabled. As with the cfg80211 callback, a change here should
 *      cause an event to be sent indicating where the current value is in
 *      relation to the newly configured threshold.
 * @cqm_rssi_low: Connection quality monitor RSSI lower threshold, a zero value
 *      implies disabled.  This is an alternative mechanism to the single
 *      threshold event and can't be enabled simultaneously with it.
 * @cqm_rssi_high: Connection quality monitor RSSI upper threshold.
 * @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. Valid in AP and IBSS 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.  INT_MIN means not configured.
 * @txpower_type: TX power adjustment used to control per packet Transmit
 *      Power Control (TPC) in lower driver for the current vif. In particular
 *      TPC is enabled if value passed in %txpower_type is
 *      NL80211_TX_POWER_LIMITED (allow using less than specified from
 *      userspace), whereas TPC is disabled if %txpower_type is set to
 *      NL80211_TX_POWER_FIXED (use value configured from userspace)
 * @p2p_noa_attr: P2P NoA attribute for P2P powersave
 * @allow_p2p_go_ps: indication for AP or P2P GO interface, whether it's allowed
 *      to use P2P PS mechanism or not. AP/P2P GO is not allowed to use P2P PS
 *      if it has associated clients without P2P PS support.
 * @max_idle_period: the time period during which the station can refrain from
 *      transmitting frames to its associated AP without being disassociated.
 *      In units of 1000 TUs. Zero value indicates that the AP did not include
 *      a (valid) BSS Max Idle Period Element.
 * @protected_keep_alive: if set, indicates that the station should send an RSN
 *      protected frame to the AP to reset the idle timer at the AP for the
 *      station.
 * @ftm_responder: whether to enable or disable fine timing measurement FTM
 *      responder functionality.
 * @ftmr_params: configurable lci/civic parameter when enabling FTM responder.
 * @nontransmitted: this BSS is a nontransmitted BSS profile
 * @transmitter_bssid: the address of transmitter AP
 * @bssid_index: index inside the multiple BSSID set
 * @bssid_indicator: 2^bssid_indicator is the maximum number of APs in set
 * @ema_ap: AP supports enhancements of discovery and advertisement of
 *      nontransmitted BSSIDs
 * @profile_periodicity: the least number of beacon frames need to be received
 *      in order to discover all the nontransmitted BSSIDs in the set.
 * @he_oper: HE operation information of the AP we are connected to
 * @he_obss_pd: OBSS Packet Detection parameters.
 * @he_bss_color: BSS coloring settings, if BSS supports HE
 */
struct ieee80211_bss_conf {
        const u8 *bssid;
        u8 htc_trig_based_pkt_ext;
        bool multi_sta_back_32bit;
        bool uora_exists;
        bool ack_enabled;
        u8 uora_ocw_range;
        u16 frame_time_rts_th;
        bool he_support;
        bool twt_requester;
        bool twt_responder;
        bool twt_protected;
        /* 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;
        u8 sync_dtim_count;
        u32 basic_rates;
        struct ieee80211_rate *beacon_rate;
        int mcast_rate[NUM_NL80211_BANDS];
        u16 ht_operation_mode;
        s32 cqm_rssi_thold;
        u32 cqm_rssi_hyst;
        s32 cqm_rssi_low;
        s32 cqm_rssi_high;
        struct cfg80211_chan_def chandef;
        struct ieee80211_mu_group_data mu_group;
        __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;
        enum nl80211_tx_power_setting txpower_type;
        struct ieee80211_p2p_noa_attr p2p_noa_attr;
        bool allow_p2p_go_ps;
        u16 max_idle_period;
        bool protected_keep_alive;
        bool ftm_responder;
        struct ieee80211_ftm_responder_params *ftmr_params;
        /* Multiple BSSID data */
        bool nontransmitted;
        u8 transmitter_bssid[ETH_ALEN];
        u8 bssid_index;
        u8 bssid_indicator;
        bool ema_ap;
        u8 profile_periodicity;
        struct {
                u32 params;
                u16 nss_set;
        } he_oper;
        struct ieee80211_he_obss_pd he_obss_pd;
        struct cfg80211_he_bss_color he_bss_color;
};

/**
 * enum mac80211_tx_info_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_OFFCHAN_TX_OK: Internal to mac80211. Used to indicate
 *      that a frame can be transmitted while the queues are stopped for
 *      off-channel operation.
 * @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_MLME_CONN_TX: This frame was transmitted by the MLME
 *      code for connection establishment, this indicates that its status
 *      should kick the MLME state machine.
 * @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).
 * @IEEE80211_TX_STAT_NOACK_TRANSMITTED: A frame that was marked with
 *      IEEE80211_TX_CTL_NO_ACK has been successfully transmitted without
 *      any errors (like issues specific to the driver/HW).
 *      This flag must not be set for frames that don't request no-ack
 *      behaviour with IEEE80211_TX_CTL_NO_ACK.
 *
 * 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_info_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_OFFCHAN_TX_OK        = BIT(13),
        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),
        IEEE80211_TX_INTFL_MLME_CONN_TX         = BIT(20),
        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),
        IEEE80211_TX_STAT_NOACK_TRANSMITTED     = BIT(31),
};

#define IEEE80211_TX_CTL_STBC_SHIFT             23

/**
 * enum mac80211_tx_control_flags - flags to describe transmit control
 *
 * @IEEE80211_TX_CTRL_PORT_CTRL_PROTO: this frame is a port control
 *      protocol frame (e.g. EAP)
 * @IEEE80211_TX_CTRL_PS_RESPONSE: This frame is a response to a poll
 *      frame (PS-Poll or uAPSD).
 * @IEEE80211_TX_CTRL_RATE_INJECT: This frame is injected with rate information
 * @IEEE80211_TX_CTRL_AMSDU: This frame is an A-MSDU frame
 * @IEEE80211_TX_CTRL_FAST_XMIT: This frame is going through the fast_xmit path
 * @IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP: This frame skips mesh path lookup
 * @IEEE80211_TX_CTRL_HW_80211_ENCAP: This frame uses hardware encapsulation
 *      (header conversion)
 * @IEEE80211_TX_CTRL_NO_SEQNO: Do not overwrite the sequence number that
 *      has already been assigned to this frame.
 *
 * These flags are used in tx_info->control.flags.
 */
enum mac80211_tx_control_flags {
        IEEE80211_TX_CTRL_PORT_CTRL_PROTO       = BIT(0),
        IEEE80211_TX_CTRL_PS_RESPONSE           = BIT(1),
        IEEE80211_TX_CTRL_RATE_INJECT           = BIT(2),
        IEEE80211_TX_CTRL_AMSDU                 = BIT(3),
        IEEE80211_TX_CTRL_FAST_XMIT             = BIT(4),
        IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP     = BIT(5),
        IEEE80211_TX_CTRL_HW_80211_ENCAP        = BIT(6),
        IEEE80211_TX_CTRL_NO_SEQNO              = BIT(7),
};

/*
 * 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

/* maximum number of rate table entries */
#define IEEE80211_TX_RATE_TABLE_SIZE    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 - 1) & ~0x7);
        rate->idx = ((nss - 1) << 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) + 1;
}

/**
 * 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
 * @tx_time_est: TX time estimate in units of 4us, used internally
 * @control: union part for control data
 * @control.rates: TX rates array to try
 * @control.rts_cts_rate_idx: rate for RTS or CTS
 * @control.use_rts: use RTS
 * @control.use_cts_prot: use RTS/CTS
 * @control.short_preamble: use short preamble (CCK only)
 * @control.skip_table: skip externally configured rate table
 * @control.jiffies: timestamp for expiry on powersave clients
 * @control.vif: virtual interface (may be NULL)
 * @control.hw_key: key to encrypt with (may be NULL)
 * @control.flags: control flags, see &enum mac80211_tx_control_flags
 * @control.enqueue_time: enqueue time (for iTXQs)
 * @driver_rates: alias to @control.rates to reserve space
 * @pad: padding
 * @rate_driver_data: driver use area if driver needs @control.rates
 * @status: union part for status data
 * @status.rates: attempted rates

 * @status.ack_signal: ACK signal
 * @status.ampdu_ack_len: AMPDU ack length
 * @status.ampdu_len: AMPDU length
 * @status.antenna: (legacy, kept only for iwlegacy)
 * @status.tx_time: airtime consumed for transmission
 * @status.is_valid_ack_signal: ACK signal is valid
 * @status.status_driver_data: driver use area
 * @ack: union part for pure ACK data
 * @ack.cookie: cookie for the ACK
 * @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;
        u32 band:3,
            ack_frame_id:13,
            hw_queue:4,
            tx_time_est:10;
        /* 2 free bits */

        union {
                struct {
                        union {
                                /* rate control */
                                struct {
                                        struct ieee80211_tx_rate rates[
                                                IEEE80211_TX_MAX_RATES];
                                        s8 rts_cts_rate_idx;
                                        u8 use_rts:1;
                                        u8 use_cts_prot:1;
                                        u8 short_preamble:1;
                                        u8 skip_table:1;
                                        /* 2 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;
                        u32 flags;
                        codel_time_t enqueue_time;
                } control;
                struct {
                        u64 cookie;
                } ack;
                struct {
                        struct ieee80211_tx_rate rates[IEEE80211_TX_MAX_RATES];
                        s32 ack_signal;
                        u8 ampdu_ack_len;
                        u8 ampdu_len;
                        u8 antenna;
                        u16 tx_time;
                        bool is_valid_ack_signal;
                        void *status_driver_data[19 / sizeof(void *)];
                } status;
                struct {
                        struct ieee80211_tx_rate driver_rates[
                                IEEE80211_TX_MAX_RATES];
                        u8 pad[4];

                        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 u16
ieee80211_info_set_tx_time_est(struct ieee80211_tx_info *info, u16 tx_time_est)
{
        /* We only have 10 bits in tx_time_est, so store airtime
         * in increments of 4us and clamp the maximum to 2**12-1
         */
        info->tx_time_est = min_t(u16, tx_time_est, 4095) >> 2;
        return info->tx_time_est << 2;
}

static inline u16
ieee80211_info_get_tx_time_est(struct ieee80211_tx_info *info)
{
        return info->tx_time_est << 2;
}

/**
 * struct ieee80211_tx_status - extended tx status info for rate control
 *
 * @sta: Station that the packet was transmitted for
 * @info: Basic tx status information
 * @skb: Packet skb (can be NULL if not provided by the driver)
 * @rate: The TX rate that was used when sending the packet
 */
struct ieee80211_tx_status {
        struct ieee80211_sta *sta;
        struct ieee80211_tx_info *info;
        struct sk_buff *skb;
        struct rate_info *rate;
};

/**
 * struct ieee80211_scan_ies - descriptors for different blocks of IEs
 *
 * This structure is used to point to different blocks of IEs in HW scan
 * and scheduled scan. These blocks contain the IEs passed by userspace
 * and the ones generated by mac80211.
 *
 * @ies: pointers to band specific IEs.
 * @len: lengths of band_specific IEs.
 * @common_ies: IEs for all bands (especially vendor specific ones)
 * @common_ie_len: length of the common_ies
 */
struct ieee80211_scan_ies {
        const u8 *ies[NUM_NL80211_BANDS];
        size_t len[NUM_NL80211_BANDS];
        const u8 *common_ies;
        size_t common_ie_len;
};


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 and 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_PN_VALIDATED: Currently only valid for CCMP/GCMP frames, this
 *      flag indicates that the PN was verified for replay protection.
 *      Note that this flag is also currently only supported when a frame
 *      is also decrypted (ie. @RX_FLAG_DECRYPTED must be set)
 * @RX_FLAG_DUP_VALIDATED: The driver should set this flag if it did
 *      de-duplication by itself.
 * @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_MACTIME_PLCP_START: The timestamp passed in the RX status (@mactime
 *      field) is valid and contains the time the SYNC preamble was received.
 * @RX_FLAG_NO_SIGNAL_VAL: The signal strength value is not present.
 *      Valid only for data frames (mainly A-MPDU)
 * @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_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)
 * @RX_FLAG_MIC_STRIPPED: The mic was stripped of this packet. Decryption was
 *      done by the hardware
 * @RX_FLAG_ONLY_MONITOR: Report frame only to monitor interfaces without
 *      processing it in any regular way.
 *      This is useful if drivers offload some frames but still want to report
 *      them for sniffing purposes.
 * @RX_FLAG_SKIP_MONITOR: Process and report frame to all interfaces except
 *      monitor interfaces.
 *      This is useful if drivers offload some frames but still want to report
 *      them for sniffing purposes.
 * @RX_FLAG_AMSDU_MORE: Some drivers may prefer to report separate A-MSDU
 *      subframes instead of a one huge frame for performance reasons.
 *      All, but the last MSDU from an A-MSDU should have this flag set. E.g.
 *      if an A-MSDU has 3 frames, the first 2 must have the flag set, while
 *      the 3rd (last) one must not have this flag set. The flag is used to
 *      deal with retransmission/duplication recovery properly since A-MSDU
 *      subframes share the same sequence number. Reported subframes can be
 *      either regular MSDU or singly A-MSDUs. Subframes must not be
 *      interleaved with other frames.
 * @RX_FLAG_RADIOTAP_VENDOR_DATA: This frame contains vendor-specific
 *      radiotap data in the skb->data (before the frame) as described by
 *      the &struct ieee80211_vendor_radiotap.
 * @RX_FLAG_ALLOW_SAME_PN: Allow the same PN as same packet before.
 *      This is used for AMSDU subframes which can have the same PN as
 *      the first subframe.
 * @RX_FLAG_ICV_STRIPPED: The ICV is stripped from this frame. CRC checking must
 *      be done in the hardware.
 * @RX_FLAG_AMPDU_EOF_BIT: Value of the EOF bit in the A-MPDU delimiter for this
 *      frame
 * @RX_FLAG_AMPDU_EOF_BIT_KNOWN: The EOF value is known
 * @RX_FLAG_RADIOTAP_HE: HE radiotap data is present
 *      (&struct ieee80211_radiotap_he, mac80211 will fill in
 *      
 *       - DATA3_DATA_MCS
 *       - DATA3_DATA_DCM
 *       - DATA3_CODING
 *       - DATA5_GI
 *       - DATA5_DATA_BW_RU_ALLOC
 *       - DATA6_NSTS
 *       - DATA3_STBC
 *      
 *      from the RX info data, so leave those zeroed when building this data)
 * @RX_FLAG_RADIOTAP_HE_MU: HE MU radiotap data is present
 *      (&struct ieee80211_radiotap_he_mu)
 * @RX_FLAG_RADIOTAP_LSIG: L-SIG radiotap data is present
 * @RX_FLAG_NO_PSDU: use the frame only for radiotap reporting, with
 *      the "0-length PSDU" field included there.  The value for it is
 *      in &struct ieee80211_rx_status.  Note that if this value isn't
 *      known the frame shouldn't be reported.
 */
enum mac80211_rx_flags {
        RX_FLAG_MMIC_ERROR              = BIT(0),
        RX_FLAG_DECRYPTED               = BIT(1),
        RX_FLAG_MACTIME_PLCP_START      = BIT(2),
        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_NO_SIGNAL_VAL           = BIT(8),
        RX_FLAG_AMPDU_DETAILS           = BIT(9),
        RX_FLAG_PN_VALIDATED            = BIT(10),
        RX_FLAG_DUP_VALIDATED           = BIT(11),
        RX_FLAG_AMPDU_LAST_KNOWN        = BIT(12),
        RX_FLAG_AMPDU_IS_LAST           = BIT(13),
        RX_FLAG_AMPDU_DELIM_CRC_ERROR   = BIT(14),
        RX_FLAG_AMPDU_DELIM_CRC_KNOWN   = BIT(15),
        RX_FLAG_MACTIME_END             = BIT(16),
        RX_FLAG_ONLY_MONITOR            = BIT(17),
        RX_FLAG_SKIP_MONITOR            = BIT(18),
        RX_FLAG_AMSDU_MORE              = BIT(19),
        RX_FLAG_RADIOTAP_VENDOR_DATA    = BIT(20),
        RX_FLAG_MIC_STRIPPED            = BIT(21),
        RX_FLAG_ALLOW_SAME_PN           = BIT(22),
        RX_FLAG_ICV_STRIPPED            = BIT(23),
        RX_FLAG_AMPDU_EOF_BIT           = BIT(24),
        RX_FLAG_AMPDU_EOF_BIT_KNOWN     = BIT(25),
        RX_FLAG_RADIOTAP_HE             = BIT(26),
        RX_FLAG_RADIOTAP_HE_MU          = BIT(27),
        RX_FLAG_RADIOTAP_LSIG           = BIT(28),
        RX_FLAG_NO_PSDU                 = BIT(29),
};

/**
 * enum mac80211_rx_encoding_flags - MCS & bandwidth flags
 *
 * @RX_ENC_FLAG_SHORTPRE: Short preamble was used for this frame
 * @RX_ENC_FLAG_SHORT_GI: Short guard interval was used
 * @RX_ENC_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_ENC_FLAG_LDPC: LDPC was used
 * @RX_ENC_FLAG_STBC_MASK: STBC 2 bit bitmask. 1 - Nss=1, 2 - Nss=2, 3 - Nss=3
 * @RX_ENC_FLAG_BF: packet was beamformed
 */
enum mac80211_rx_encoding_flags {
        RX_ENC_FLAG_SHORTPRE            = BIT(0),
        RX_ENC_FLAG_SHORT_GI            = BIT(2),
        RX_ENC_FLAG_HT_GF               = BIT(3),
        RX_ENC_FLAG_STBC_MASK           = BIT(4) | BIT(5),
        RX_ENC_FLAG_LDPC                = BIT(6),
        RX_ENC_FLAG_BF                  = BIT(7),
};

#define RX_ENC_FLAG_STBC_SHIFT          4

enum mac80211_rx_encoding {
        RX_ENC_LEGACY = 0,
        RX_ENC_HT,
        RX_ENC_VHT,
        RX_ENC_HE,
};

/**
 * 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.
 * @boottime_ns: CLOCK_BOOTTIME timestamp the frame was received at, this is
 *      needed only for beacons and probe responses that update the scan cache.
 * @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
 *      This field must be set for management frames, but isn't strictly needed
 *      for data (other) frames - for those it only affects radiotap reporting.
 * @freq_offset: @freq has a positive offset of 500Khz.
 * @signal: signal strength when receiving this frame, either in dBm, in dB or
 *      unspecified depending on the hardware capabilities flags
 *      @IEEE80211_HW_SIGNAL_*
 * @chains: bitmask of receive chains for which separate signal strength
 *      values were filled.
 * @chain_signal: per-chain signal strength, in dBm (unlike @signal, doesn't
 *      support dB or unspecified units)
 * @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)
 * @nss: number of streams (VHT and HE only)
 * @flag: %RX_FLAG_\*
 * @encoding: &enum mac80211_rx_encoding
 * @bw: &enum rate_info_bw
 * @enc_flags: uses bits from &enum mac80211_rx_encoding_flags
 * @he_ru: HE RU, from &enum nl80211_he_ru_alloc
 * @he_gi: HE GI, from &enum nl80211_he_gi
 * @he_dcm: HE DCM value
 * @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
 * @zero_length_psdu_type: radiotap type of the 0-length PSDU
 */
struct ieee80211_rx_status {
        u64 mactime;
        u64 boottime_ns;
        u32 device_timestamp;
        u32 ampdu_reference;
        u32 flag;
        u16 freq: 13, freq_offset: 1;
        u8 enc_flags;
        u8 encoding:2, bw:3, he_ru:3;
        u8 he_gi:2, he_dcm:1;
        u8 rate_idx;
        u8 nss;
        u8 rx_flags;
        u8 band;
        u8 antenna;
        s8 signal;
        u8 chains;
        s8 chain_signal[IEEE80211_MAX_CHAINS];
        u8 ampdu_delimiter_crc;
        u8 zero_length_psdu_type;
};

static inline u32
ieee80211_rx_status_to_khz(struct ieee80211_rx_status *rx_status)
{
        return MHZ_TO_KHZ(rx_status->freq) +
               (rx_status->freq_offset ? 500 : 0);
}

/**
 * struct ieee80211_vendor_radiotap - vendor radiotap data information
 * @present: presence bitmap for this vendor namespace
 *      (this could be extended in the future if any vendor needs more
 *       bits, the radiotap spec does allow for that)
 * @align: radiotap vendor namespace alignment. This defines the needed
 *      alignment for the @data field below, not for the vendor namespace
 *      description itself (which has a fixed 2-byte alignment)
 *      Must be a power of two, and be set to at least 1!
 * @oui: radiotap vendor namespace OUI
 * @subns: radiotap vendor sub namespace
 * @len: radiotap vendor sub namespace skip length, if alignment is done
 *      then that's added to this, i.e. this is only the length of the
 *      @data field.
 * @pad: number of bytes of padding after the @data, this exists so that
 *      the skb data alignment can be preserved even if the data has odd
 *      length
 * @data: the actual vendor namespace data
 *
 * This struct, including the vendor data, goes into the skb->data before
 * the 802.11 header. It's split up in mac80211 using the align/oui/subns
 * data.
 */
struct ieee80211_vendor_radiotap {
        u32 present;
        u8 align;
        u8 oui[3];
        u8 subns;
        u8 pad;
        u16 len;
        u8 data[];
} __packed;

/**
 * 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
 * @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
 *
 * @chandef: the channel definition to tune to
 * @radar_enabled: whether radar detection is enabled
 *
 * @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;

        u16 listen_interval;
        u8 ps_dtim_period;

        u8 long_frame_max_tx_count, short_frame_max_tx_count;

        struct cfg80211_chan_def chandef;
        bool radar_enabled;
        enum ieee80211_smps_mode smps_mode;
};

/**
 * struct ieee80211_channel_switch - holds the channel switch data
 *
 * The information provided in this structure is required for channel switch
 * operation.
 *
 * @timestamp: value in microseconds of the 64-bit Time Synchronization
 *      Function (TSF) timer when the frame containing the channel switch
 *      announcement was received. This is simply the rx.mactime parameter
 *      the driver passed into mac80211.
 * @device_timestamp: arbitrary timestamp for the device, this is the
 *      rx.device_timestamp parameter the driver passed to mac80211.
 * @block_tx: Indicates whether transmission must be blocked before the
 *      scheduled channel switch, as indicated by the AP.
 * @chandef: the new channel to switch to
 * @count: the number of TBTT's until the channel switch event
 * @delay: maximum delay between the time the AP transmitted the last beacon in
  *     current channel and the expected time of the first beacon in the new
  *     channel, expressed in TU.
 */
struct ieee80211_channel_switch {
        u64 timestamp;
        u32 device_timestamp;
        bool block_tx;
        struct cfg80211_chan_def chandef;
        u8 count;
        u32 delay;
};

/**
 * enum ieee80211_vif_flags - virtual interface flags
 *
 * @IEEE80211_VIF_BEACON_FILTER: the device performs beacon filtering
 *      on this virtual interface to avoid unnecessary CPU wakeups
 * @IEEE80211_VIF_SUPPORTS_CQM_RSSI: the device can do connection quality
 *      monitoring on this virtual interface -- i.e. it can monitor
 *      connection quality related parameters, such as the RSSI level and
 *      provide notifications if configured trigger levels are reached.
 * @IEEE80211_VIF_SUPPORTS_UAPSD: The device can do U-APSD for this
 *      interface. This flag should be set during interface addition,
 *      but may be set/cleared as late as authentication to an AP. It is
 *      only valid for managed/station mode interfaces.
 * @IEEE80211_VIF_GET_NOA_UPDATE: request to handle NOA attributes
 *      and send P2P_PS notification to the driver if NOA changed, even
 *      this is not pure P2P vif.
 */
enum ieee80211_vif_flags {
        IEEE80211_VIF_BEACON_FILTER             = BIT(0),
        IEEE80211_VIF_SUPPORTS_CQM_RSSI         = BIT(1),
        IEEE80211_VIF_SUPPORTS_UAPSD            = BIT(2),
        IEEE80211_VIF_GET_NOA_UPDATE            = BIT(3),
};

/**
 * 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
 * @p2p: indicates whether this AP or STA interface is a p2p
 *      interface, i.e. a GO or p2p-sta respectively
 * @csa_active: marks whether a channel switch is going on. Internally it is
 *      write-protected by sdata_lock and local->mtx so holding either is fine
 *      for read access.
 * @mu_mimo_owner: indicates interface owns MU-MIMO capability
 * @driver_flags: flags/capabilities the driver has for this interface,
 *      these need to be set (or cleared) when the interface is added
 *      or, if supported by the driver, the interface type is changed
 *      at runtime, mac80211 will never touch this field
 * @hw_queue: hardware queue for each AC
 * @cab_queue: content-after-beacon (DTIM beacon really) queue, AP mode only
 * @chanctx_conf: The channel context this interface is assigned to, or %NULL
 *      when it is not assigned. This pointer is RCU-protected due to the TX
 *      path needing to access it; even though the netdev carrier will always
 *      be off when it is %NULL there can still be races and packets could be
 *      processed after it switches back to %NULL.
 * @debugfs_dir: debugfs dentry, can be used by drivers to create own per
 *      interface debug files. Note that it will be NULL for the virtual
 *      monitor interface (if that is requested.)
 * @probe_req_reg: probe requests should be reported to mac80211 for this
 *      interface.
 * @rx_mcast_action_reg: multicast Action frames should be reported to mac80211
 *      for this interface.
 * @drv_priv: data area for driver use, will always be aligned to
 *      sizeof(void \*).
 * @txq: the multicast data TX queue (if driver uses the TXQ abstraction)
 * @txqs_stopped: per AC flag to indicate that intermediate TXQs are stopped,
 *      protected by fq->lock.
 */
struct ieee80211_vif {
        enum nl80211_iftype type;
        struct ieee80211_bss_conf bss_conf;
        u8 addr[ETH_ALEN] __aligned(2);
        bool p2p;
        bool csa_active;
        bool mu_mimo_owner;

        u8 cab_queue;
        u8 hw_queue[IEEE80211_NUM_ACS];

        struct ieee80211_txq *txq;

        struct ieee80211_chanctx_conf __rcu *chanctx_conf;

        u32 driver_flags;

#ifdef CONFIG_MAC80211_DEBUGFS
        struct dentry *debugfs_dir;
#endif

        bool probe_req_reg;
        bool rx_mcast_action_reg;

        bool txqs_stopped[IEEE80211_NUM_ACS];

        /* must be last */
        u8 drv_priv[] __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;
}

/**
 * wdev_to_ieee80211_vif - return a vif struct from a wdev
 * @wdev: the wdev to get the vif for
 *
 * This can be used by mac80211 drivers with direct cfg80211 APIs
 * (like the vendor commands) that get a wdev.
 *
 * Note that this function may return %NULL if the given wdev isn't
 * associated with a vif that the driver knows about (e.g. monitor
 * or AP_VLAN interfaces.)
 */
struct ieee80211_vif *wdev_to_ieee80211_vif(struct wireless_dev *wdev);

/**
 * ieee80211_vif_to_wdev - return a wdev struct from a vif
 * @vif: the vif to get the wdev for
 *
 * This can be used by mac80211 drivers with direct cfg80211 APIs
 * (like the vendor commands) that needs to get the wdev for a vif.
 *
 * Note that this function may return %NULL if the given wdev isn't
 * associated with a vif that the driver knows about (e.g. monitor
 * or AP_VLAN interfaces.)
 */
struct wireless_dev *ieee80211_vif_to_wdev(struct ieee80211_vif *vif);

/**
 * 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_GENERATE_IV: This flag should be set by the
 *      driver to indicate that it requires IV generation for this
 *      particular key. Setting this flag does not necessarily mean that SKBs
 *      will have sufficient tailroom for ICV or MIC.
 * @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_TX: This flag should be set by the driver for a
 *      CCMP/GCMP key if it requires CCMP/GCMP encryption of management frames
 *      (MFP) to be done in software.
 * @IEEE80211_KEY_FLAG_PUT_IV_SPACE: This flag should be set by the driver
 *      if space should be prepared for the IV, but the IV
 *      itself should not be generated. Do not set together with
 *      @IEEE80211_KEY_FLAG_GENERATE_IV on the same key. Setting this flag does
 *      not necessarily mean that SKBs will have sufficient tailroom for ICV or
 *      MIC.
 * @IEEE80211_KEY_FLAG_RX_MGMT: This key will be used to decrypt received
 *      management frames. The flag can help drivers that have a hardware
 *      crypto implementation that doesn't deal with management frames
 *      properly by allowing them to not upload the keys to hardware and
 *      fall back to software crypto. Note that this flag deals only with
 *      RX, if your crypto engine can't deal with TX you can also set the
 *      %IEEE80211_KEY_FLAG_SW_MGMT_TX flag to encrypt such frames in SW.
 * @IEEE80211_KEY_FLAG_GENERATE_IV_MGMT: This flag should be set by the
 *      driver for a CCMP/GCMP key to indicate that is requires IV generation
 *      only for management frames (MFP).
 * @IEEE80211_KEY_FLAG_RESERVE_TAILROOM: This flag should be set by the
 *      driver for a key to indicate that sufficient tailroom must always
 *      be reserved for ICV or MIC, even when HW encryption is enabled.
 * @IEEE80211_KEY_FLAG_PUT_MIC_SPACE: This flag should be set by the driver for
 *      a TKIP key if it only requires MIC space. Do not set together with
 *      @IEEE80211_KEY_FLAG_GENERATE_MMIC on the same key.
 * @IEEE80211_KEY_FLAG_NO_AUTO_TX: Key needs explicit Tx activation.
 * @IEEE80211_KEY_FLAG_GENERATE_MMIE: This flag should be set by the driver
 *      for a AES_CMAC key to indicate that it requires sequence number
 *      generation only
 */
enum ieee80211_key_flags {
        IEEE80211_KEY_FLAG_GENERATE_IV_MGMT     = BIT(0),
        IEEE80211_KEY_FLAG_GENERATE_IV          = BIT(1),
        IEEE80211_KEY_FLAG_GENERATE_MMIC        = BIT(2),
        IEEE80211_KEY_FLAG_PAIRWISE             = BIT(3),
        IEEE80211_KEY_FLAG_SW_MGMT_TX           = BIT(4),
        IEEE80211_KEY_FLAG_PUT_IV_SPACE         = BIT(5),
        IEEE80211_KEY_FLAG_RX_MGMT              = BIT(6),
        IEEE80211_KEY_FLAG_RESERVE_TAILROOM     = BIT(7),
        IEEE80211_KEY_FLAG_PUT_MIC_SPACE        = BIT(8),
        IEEE80211_KEY_FLAG_NO_AUTO_TX           = BIT(9),
        IEEE80211_KEY_FLAG_GENERATE_MMIE        = BIT(10),
};

/**
 * 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.
 * @cipher: The key's cipher suite selector.
 * @tx_pn: PN used for TX keys, may be used by the driver as well if it
 *      needs to do software PN assignment by itself (e.g. due to TSO)
 * @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 {
        atomic64_t tx_pn;
        u32 cipher;
        u8 icv_len;
        u8 iv_len;
        u8 hw_key_idx;
        s8 keyidx;
        u16 flags;
        u8 keylen;
        u8 key[];
};

#define IEEE80211_MAX_PN_LEN    16

#define TKIP_PN_TO_IV16(pn) ((u16)(pn & 0xffff))
#define TKIP_PN_TO_IV32(pn) ((u32)((pn >> 16) & 0xffffffff))

/**
 * struct ieee80211_key_seq - key sequence counter
 *
 * @tkip: TKIP data, containing IV32 and IV16 in host byte order
 * @ccmp: PN data, most significant byte first (big endian,
 *      reverse order than in packet)
 * @aes_cmac: PN data, most significant byte first (big endian,
 *      reverse order than in packet)
 * @aes_gmac: PN data, most significant byte first (big endian,
 *      reverse order than in packet)
 * @gcmp: PN data, most significant byte first (big endian,
 *      reverse order than in packet)
 * @hw: data for HW-only (e.g. cipher scheme) keys
 */
struct ieee80211_key_seq {
        union {
                struct {
                        u32 iv32;
                        u16 iv16;
                } tkip;
                struct {
                        u8 pn[6];
                } ccmp;
                struct {
                        u8 pn[6];
                } aes_cmac;
                struct {
                        u8 pn[6];
                } aes_gmac;
                struct {
                        u8 pn[6];
                } gcmp;
                struct {
                        u8 seq[IEEE80211_MAX_PN_LEN];
                        u8 seq_len;
                } hw;
        };
};

/**
 * struct ieee80211_cipher_scheme - cipher scheme
 *
 * This structure contains a cipher scheme information defining
 * the secure packet crypto handling.
 *
 * @cipher: a cipher suite selector
 * @iftype: a cipher iftype bit mask indicating an allowed cipher usage
 * @hdr_len: a length of a security header used the cipher
 * @pn_len: a length of a packet number in the security header
 * @pn_off: an offset of pn from the beginning of the security header
 * @key_idx_off: an offset of key index byte in the security header
 * @key_idx_mask: a bit mask of key_idx bits
 * @key_idx_shift: a bit shift needed to get key_idx
 *     key_idx value calculation:
 *      (sec_header_base[key_idx_off] & key_idx_mask) >> key_idx_shift
 * @mic_len: a mic length in bytes
 */
struct ieee80211_cipher_scheme {
        u32 cipher;
        u16 iftype;
        u8 hdr_len;
        u8 pn_len;
        u8 pn_off;
        u8 key_idx_off;
        u8 key_idx_mask;
        u8 key_idx_shift;
        u8 mic_len;
};

/**
 * 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,
};

/**
 * enum ieee80211_sta_state - station state
 *
 * @IEEE80211_STA_NOTEXIST: station doesn't exist at all,
 *      this is a special state for add/remove transitions
 * @IEEE80211_STA_NONE: station exists without special state
 * @IEEE80211_STA_AUTH: station is authenticated
 * @IEEE80211_STA_ASSOC: station is associated
 * @IEEE80211_STA_AUTHORIZED: station is authorized (802.1X)
 */
enum ieee80211_sta_state {
        /* NOTE: These need to be ordered correctly! */
        IEEE80211_STA_NOTEXIST,
        IEEE80211_STA_NONE,
        IEEE80211_STA_AUTH,
        IEEE80211_STA_ASSOC,
        IEEE80211_STA_AUTHORIZED,
};

/**
 * enum ieee80211_sta_rx_bandwidth - station RX bandwidth
 * @IEEE80211_STA_RX_BW_20: station can only receive 20 MHz
 * @IEEE80211_STA_RX_BW_40: station can receive up to 40 MHz
 * @IEEE80211_STA_RX_BW_80: station can receive up to 80 MHz
 * @IEEE80211_STA_RX_BW_160: station can receive up to 160 MHz
 *      (including 80+80 MHz)
 *
 * Implementation note: 20 must be zero to be initialized
 *      correctly, the values must be sorted.
 */
enum ieee80211_sta_rx_bandwidth {
        IEEE80211_STA_RX_BW_20 = 0,
        IEEE80211_STA_RX_BW_40,
        IEEE80211_STA_RX_BW_80,
        IEEE80211_STA_RX_BW_160,
};

/**
 * struct ieee80211_sta_rates - station rate selection table
 *
 * @rcu_head: RCU head used for freeing the table on update
 * @rate: transmit rates/flags to be used by default.
 *      Overriding entries per-packet is possible by using cb tx control.
 */
struct ieee80211_sta_rates {
        struct rcu_head rcu_head;
        struct {
                s8 idx;
                u8 count;
                u8 count_cts;
                u8 count_rts;
                u16 flags;
        } rate[IEEE80211_TX_RATE_TABLE_SIZE];
};

/**
 * struct ieee80211_sta_txpwr - station txpower configuration
 *
 * Used to configure txpower for station.
 *
 * @power: indicates the tx power, in dBm, to be used when sending data frames
 *      to the STA.
 * @type: In particular if TPC %type is NL80211_TX_POWER_LIMITED then tx power
 *      will be less than or equal to specified from userspace, whereas if TPC
 *      %type is NL80211_TX_POWER_AUTOMATIC then it indicates default tx power.
 *      NL80211_TX_POWER_FIXED is not a valid configuration option for
 *      per peer TPC.
 */
struct ieee80211_sta_txpwr {
        s16 power;
        enum nl80211_tx_power_setting type;
};

/**
 * 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 capabilities
 * @vht_cap: VHT capabilities of this STA; restricted to our own capabilities
 * @he_cap: HE capabilities of this STA
 * @he_6ghz_capa: on 6 GHz, holds the HE 6 GHz band capabilities
 * @max_rx_aggregation_subframes: maximal amount of frames in a single AMPDU
 *      that this station is allowed to transmit to us.
 *      Can be modified by driver.
 * @wme: indicates whether the STA supports QoS/WME (if local devices does,
 *      otherwise always false)
 * @drv_priv: data area for driver use, will always be aligned to
 *      sizeof(void \*), size is determined in hw information.
 * @uapsd_queues: bitmap of queues configured for uapsd. Only valid
 *      if wme is supported. The bits order is like in
 *      IEEE80211_WMM_IE_STA_QOSINFO_AC_*.
 * @max_sp: max Service Period. Only valid if wme is supported.
 * @bandwidth: current bandwidth the station can receive with
 * @rx_nss: in HT/VHT, the maximum number of spatial streams the
 *      station can receive at the moment, changed by operating mode
 *      notifications and capabilities. The value is only valid after
 *      the station moves to associated state.
 * @smps_mode: current SMPS mode (off, static or dynamic)

 * @rates: rate control selection table
 * @tdls: indicates whether the STA is a TDLS peer
 * @tdls_initiator: indicates the STA is an initiator of the TDLS link. Only
 *      valid if the STA is a TDLS peer in the first place.
 * @mfp: indicates whether the STA uses management frame protection or not.
 * @max_amsdu_subframes: indicates the maximal number of MSDUs in a single
 *      A-MSDU. Taken from the Extended Capabilities element. 0 means
 *      unlimited.
 * @support_p2p_ps: indicates whether the STA supports P2P PS mechanism or not.
 * @max_rc_amsdu_len: Maximum A-MSDU size in bytes recommended by rate control.
 * @max_tid_amsdu_len: Maximum A-MSDU size in bytes for this TID
 * @txpwr: the station tx power configuration
 * @txq: per-TID data TX queues (if driver uses the TXQ abstraction); note that
 *      the last entry (%IEEE80211_NUM_TIDS) is used for non-data frames
 */
struct ieee80211_sta {
        u32 supp_rates[NUM_NL80211_BANDS];
        u8 addr[ETH_ALEN];
        u16 aid;
        struct ieee80211_sta_ht_cap ht_cap;
        struct ieee80211_sta_vht_cap vht_cap;
        struct ieee80211_sta_he_cap he_cap;
        struct ieee80211_he_6ghz_capa he_6ghz_capa;
        u16 max_rx_aggregation_subframes;
        bool wme;
        u8 uapsd_queues;
        u8 max_sp;
        u8 rx_nss;
        enum ieee80211_sta_rx_bandwidth bandwidth;
        enum ieee80211_smps_mode smps_mode;
        struct ieee80211_sta_rates __rcu *rates;
        bool tdls;
        bool tdls_initiator;
        bool mfp;
        u8 max_amsdu_subframes;

        /**
         * @max_amsdu_len:
         * indicates the maximal length of an A-MSDU in bytes.
         * This field is always valid for packets with a VHT preamble.
         * For packets with a HT preamble, additional limits apply:
         *
         * * If the skb is transmitted as part of a BA agreement, the
         *   A-MSDU maximal size is min(max_amsdu_len, 4065) bytes.
         * * If the skb is not part of a BA agreement, the A-MSDU maximal
         *   size is min(max_amsdu_len, 7935) bytes.
         *
         * Both additional HT limits must be enforced by the low level
         * driver. This is defined by the spec (IEEE 802.11-2012 section
         * 8.3.2.2 NOTE 2).
         */
        u16 max_amsdu_len;
        bool support_p2p_ps;
        u16 max_rc_amsdu_len;
        u16 max_tid_amsdu_len[IEEE80211_NUM_TIDS];
        struct ieee80211_sta_txpwr txpwr;

        struct ieee80211_txq *txq[IEEE80211_NUM_TIDS + 1];

        /* must be last */
        u8 drv_priv[] __aligned(sizeof(void *));
};

/**
 * enum sta_notify_cmd - sta notify command
 *
 * Used with the sta_notify() callback in &struct ieee80211_ops, this
 * indicates if an associated station made a power state transition.
 *
 * @STA_NOTIFY_SLEEP: a station is now sleeping
 * @STA_NOTIFY_AWAKE: a sleeping station woke up
 */
enum sta_notify_cmd {
        STA_NOTIFY_SLEEP, STA_NOTIFY_AWAKE,
};

/**
 * struct ieee80211_tx_control - TX control data
 *
 * @sta: station table entry, this sta pointer may be NULL and
 *      it is not allowed to copy the pointer, due to RCU.
 */
struct ieee80211_tx_control {
        struct ieee80211_sta *sta;
};

/**
 * struct ieee80211_txq - Software intermediate tx queue
 *
 * @vif: &struct ieee80211_vif pointer from the add_interface callback.
 * @sta: station table entry, %NULL for per-vif queue
 * @tid: the TID for this queue (unused for per-vif queue),
 *      %IEEE80211_NUM_TIDS for non-data (if enabled)
 * @ac: the AC for this queue
 * @drv_priv: driver private area, sized by hw->txq_data_size
 *
 * The driver can obtain packets from this queue by calling
 * ieee80211_tx_dequeue().
 */
struct ieee80211_txq {
        struct ieee80211_vif *vif;
        struct ieee80211_sta *sta;
        u8 tid;
        u8 ac;

        /* must be last */
        u8 drv_priv[] __aligned(sizeof(void *));
};

/**
 * 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_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_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_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.
 *
 * @IEEE80211_HW_NEED_DTIM_BEFORE_ASSOC:
 *      This device needs to get data from beacon before association (i.e.
 *      dtim_period).
 *
 * @IEEE80211_HW_SUPPORTS_PER_STA_GTK: The device's crypto engine supports
 *      per-station GTKs as used by IBSS RSN or during fast transition. If
 *      the device doesn't support per-station GTKs, but can be asked not
 *      to decrypt group addressed frames, then IBSS RSN support is still
 *      possible but software crypto will be used. Advertise the wiphy flag
 *      only in that case.
 *
 * @IEEE80211_HW_AP_LINK_PS: When operating in AP mode the device
 *      autonomously manages the PS status of connected stations. When
 *      this flag is set mac80211 will not trigger PS mode for connected
 *      stations based on the PM bit of incoming frames.
 *      Use ieee80211_start_ps()/ieee8021_end_ps() to manually configure
 *      the PS mode of connected stations.
 *
 * @IEEE80211_HW_TX_AMPDU_SETUP_IN_HW: The device handles TX A-MPDU session
 *      setup strictly in HW. mac80211 should not attempt to do this in
 *      software.
 *
 * @IEEE80211_HW_WANT_MONITOR_VIF: The driver would like to be informed of
 *      a virtual monitor interface when monitor interfaces are the only
 *      active interfaces.
 *
 * @IEEE80211_HW_NO_AUTO_VIF: The driver would like for no wlanX to
 *      be created.  It is expected user-space will create vifs as
 *      desired (and thus have them named as desired).
 *
 * @IEEE80211_HW_SW_CRYPTO_CONTROL: The driver wants to control which of the
 *      crypto algorithms can be done in software - so don't automatically
 *      try to fall back to it if hardware crypto fails, but do so only if
 *      the driver returns 1. This also forces the driver to advertise its
 *      supported cipher suites.
 *
 * @IEEE80211_HW_SUPPORT_FAST_XMIT: The driver/hardware supports fast-xmit,
 *      this currently requires only the ability to calculate the duration
 *      for frames.
 *
 * @IEEE80211_HW_QUEUE_CONTROL: The driver wants to control per-interface
 *      queue mapping in order to use different queues (not just one per AC)
 *      for different virtual interfaces. See the doc section on HW queue
 *      control for more details.
 *
 * @IEEE80211_HW_SUPPORTS_RC_TABLE: The driver supports using a rate
 *      selection table provided by the rate control algorithm.
 *
 * @IEEE80211_HW_P2P_DEV_ADDR_FOR_INTF: Use the P2P Device address for any
 *      P2P Interface. This will be honoured even if more than one interface
 *      is supported.
 *
 * @IEEE80211_HW_TIMING_BEACON_ONLY: Use sync timing from beacon frames
 *      only, to allow getting TBTT of a DTIM beacon.
 *
 * @IEEE80211_HW_SUPPORTS_HT_CCK_RATES: Hardware supports mixing HT/CCK rates
 *      and can cope with CCK rates in an aggregation session (e.g. by not
 *      using aggregation for such frames.)
 *
 * @IEEE80211_HW_CHANCTX_STA_CSA: Support 802.11h based channel-switch (CSA)
 *      for a single active channel while using channel contexts. When support
 *      is not enabled the default action is to disconnect when getting the
 *      CSA frame.
 *
 * @IEEE80211_HW_SUPPORTS_CLONED_SKBS: The driver will never modify the payload
 *      or tailroom of TX skbs without copying them first.
 *
 * @IEEE80211_HW_SINGLE_SCAN_ON_ALL_BANDS: The HW supports scanning on all bands
 *      in one command, mac80211 doesn't have to run separate scans per band.
 *
 * @IEEE80211_HW_TDLS_WIDER_BW: The device/driver supports wider bandwidth
 *      than then BSS bandwidth for a TDLS link on the base channel.
 *
 * @IEEE80211_HW_SUPPORTS_AMSDU_IN_AMPDU: The driver supports receiving A-MSDUs
 *      within A-MPDU.
 *
 * @IEEE80211_HW_BEACON_TX_STATUS: The device/driver provides TX status
 *      for sent beacons.
 *
 * @IEEE80211_HW_NEEDS_UNIQUE_STA_ADDR: Hardware (or driver) requires that each
 *      station has a unique address, i.e. each station entry can be identified
 *      by just its MAC address; this prevents, for example, the same station
 *      from connecting to two virtual AP interfaces at the same time.
 *
 * @IEEE80211_HW_SUPPORTS_REORDERING_BUFFER: Hardware (or driver) manages the
 *      reordering buffer internally, guaranteeing mac80211 receives frames in
 *      order and does not need to manage its own reorder buffer or BA session
 *      timeout.
 *
 * @IEEE80211_HW_USES_RSS: The device uses RSS and thus requires parallel RX,
 *      which implies using per-CPU station statistics.
 *
 * @IEEE80211_HW_TX_AMSDU: Hardware (or driver) supports software aggregated
 *      A-MSDU frames. Requires software tx queueing and fast-xmit support.
 *      When not using minstrel/minstrel_ht rate control, the driver must
 *      limit the maximum A-MSDU size based on the current tx rate by setting
 *      max_rc_amsdu_len in struct ieee80211_sta.
 *
 * @IEEE80211_HW_TX_FRAG_LIST: Hardware (or driver) supports sending frag_list
 *      skbs, needed for zero-copy software A-MSDU.
 *
 * @IEEE80211_HW_REPORTS_LOW_ACK: The driver (or firmware) reports low ack event
 *      by ieee80211_report_low_ack() based on its own algorithm. For such
 *      drivers, mac80211 packet loss mechanism will not be triggered and driver
 *      is completely depending on firmware event for station kickout.
 *
 * @IEEE80211_HW_SUPPORTS_TX_FRAG: Hardware does fragmentation by itself.
 *      The stack will not do fragmentation.
 *      The callback for @set_frag_threshold should be set as well.
 *
 * @IEEE80211_HW_SUPPORTS_TDLS_BUFFER_STA: Hardware supports buffer STA on
 *      TDLS links.
 *
 * @IEEE80211_HW_DEAUTH_NEED_MGD_TX_PREP: The driver requires the
 *      mgd_prepare_tx() callback to be called before transmission of a
 *      deauthentication frame in case the association was completed but no
 *      beacon was heard. This is required in multi-channel scenarios, where the
 *      virtual interface might not be given air time for the transmission of
 *      the frame, as it is not synced with the AP/P2P GO yet, and thus the
 *      deauthentication frame might not be transmitted.
 *
 * @IEEE80211_HW_DOESNT_SUPPORT_QOS_NDP: The driver (or firmware) doesn't
 *      support QoS NDP for AP probing - that's most likely a driver bug.
 *
 * @IEEE80211_HW_BUFF_MMPDU_TXQ: use the TXQ for bufferable MMPDUs, this of
 *      course requires the driver to use TXQs to start with.
 *
 * @IEEE80211_HW_SUPPORTS_VHT_EXT_NSS_BW: (Hardware) rate control supports VHT
 *      extended NSS BW (dot11VHTExtendedNSSBWCapable). This flag will be set if
 *      the selected rate control algorithm sets %RATE_CTRL_CAPA_VHT_EXT_NSS_BW
 *      but if the rate control is built-in then it must be set by the driver.
 *      See also the documentation for that flag.
 *
 * @IEEE80211_HW_STA_MMPDU_TXQ: use the extra non-TID per-station TXQ for all
 *      MMPDUs on station interfaces. This of course requires the driver to use
 *      TXQs to start with.
 *
 * @IEEE80211_HW_TX_STATUS_NO_AMPDU_LEN: Driver does not report accurate A-MPDU
 *      length in tx status information
 *
 * @IEEE80211_HW_SUPPORTS_MULTI_BSSID: Hardware supports multi BSSID
 *
 * @IEEE80211_HW_SUPPORTS_ONLY_HE_MULTI_BSSID: Hardware supports multi BSSID
 *      only for HE APs. Applies if @IEEE80211_HW_SUPPORTS_MULTI_BSSID is set.
 *
 * @IEEE80211_HW_AMPDU_KEYBORDER_SUPPORT: The card and driver is only
 *      aggregating MPDUs with the same keyid, allowing mac80211 to keep Tx
 *      A-MPDU sessions active while rekeying with Extended Key ID.
 *
 * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
 */
enum ieee80211_hw_flags {
        IEEE80211_HW_HAS_RATE_CONTROL,
        IEEE80211_HW_RX_INCLUDES_FCS,
        IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING,
        IEEE80211_HW_SIGNAL_UNSPEC,
        IEEE80211_HW_SIGNAL_DBM,
        IEEE80211_HW_NEED_DTIM_BEFORE_ASSOC,
        IEEE80211_HW_SPECTRUM_MGMT,
        IEEE80211_HW_AMPDU_AGGREGATION,
        IEEE80211_HW_SUPPORTS_PS,
        IEEE80211_HW_PS_NULLFUNC_STACK,
        IEEE80211_HW_SUPPORTS_DYNAMIC_PS,
        IEEE80211_HW_MFP_CAPABLE,
        IEEE80211_HW_WANT_MONITOR_VIF,
        IEEE80211_HW_NO_AUTO_VIF,
        IEEE80211_HW_SW_CRYPTO_CONTROL,
        IEEE80211_HW_SUPPORT_FAST_XMIT,
        IEEE80211_HW_REPORTS_TX_ACK_STATUS,
        IEEE80211_HW_CONNECTION_MONITOR,
        IEEE80211_HW_QUEUE_CONTROL,
        IEEE80211_HW_SUPPORTS_PER_STA_GTK,
        IEEE80211_HW_AP_LINK_PS,
        IEEE80211_HW_TX_AMPDU_SETUP_IN_HW,
        IEEE80211_HW_SUPPORTS_RC_TABLE,
        IEEE80211_HW_P2P_DEV_ADDR_FOR_INTF,
        IEEE80211_HW_TIMING_BEACON_ONLY,
        IEEE80211_HW_SUPPORTS_HT_CCK_RATES,
        IEEE80211_HW_CHANCTX_STA_CSA,
        IEEE80211_HW_SUPPORTS_CLONED_SKBS,
        IEEE80211_HW_SINGLE_SCAN_ON_ALL_BANDS,
        IEEE80211_HW_TDLS_WIDER_BW,
        IEEE80211_HW_SUPPORTS_AMSDU_IN_AMPDU,
        IEEE80211_HW_BEACON_TX_STATUS,
        IEEE80211_HW_NEEDS_UNIQUE_STA_ADDR,
        IEEE80211_HW_SUPPORTS_REORDERING_BUFFER,
        IEEE80211_HW_USES_RSS,
        IEEE80211_HW_TX_AMSDU,
        IEEE80211_HW_TX_FRAG_LIST,
        IEEE80211_HW_REPORTS_LOW_ACK,
        IEEE80211_HW_SUPPORTS_TX_FRAG,
        IEEE80211_HW_SUPPORTS_TDLS_BUFFER_STA,
        IEEE80211_HW_DEAUTH_NEED_MGD_TX_PREP,
        IEEE80211_HW_DOESNT_SUPPORT_QOS_NDP,
        IEEE80211_HW_BUFF_MMPDU_TXQ,
        IEEE80211_HW_SUPPORTS_VHT_EXT_NSS_BW,
        IEEE80211_HW_STA_MMPDU_TXQ,
        IEEE80211_HW_TX_STATUS_NO_AMPDU_LEN,
        IEEE80211_HW_SUPPORTS_MULTI_BSSID,
        IEEE80211_HW_SUPPORTS_ONLY_HE_MULTI_BSSID,
        IEEE80211_HW_AMPDU_KEYBORDER_SUPPORT,

        /* keep last, obviously */
        NUM_IEEE80211_HW_FLAGS
};

/**
 * 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.)
 *
 * @extra_beacon_tailroom: tailroom to reserve in each beacon tx skb.
 *      Can be used by drivers to add extra IEs.
 *
 * @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.
 * @chanctx_data_size: size (in bytes) of the drv_priv data area
 *      within &struct ieee80211_chanctx_conf.
 * @txq_data_size: size (in bytes) of the drv_priv data area
 *      within @struct ieee80211_txq.
 *
 * @max_rates: maximum number of alternate rate retry stages the hw
 *      can handle.
 * @max_report_rates: maximum number of alternate rate retry stages
 *      the hw can report back.
 * @max_rate_tries: maximum number of tries for each stage
 *
 * @max_rx_aggregation_subframes: maximum buffer size (number of
 *      sub-frames) to be used for A-MPDU block ack receiver
 *      aggregation.
 *      This is only relevant if the device has restrictions on the
 *      number of subframes, if it relies on mac80211 to do reordering
 *      it shouldn't be set.
 *
 * @max_tx_aggregation_subframes: maximum number of subframes in an
 *      aggregate an HT/HE device will transmit. In HT AddBA we'll
 *      advertise a constant value of 64 as some older APs crash if
 *      the window size is smaller (an example is LinkSys WRT120N
 *      with FW v1.0.07 build 002 Jun 18 2012).
 *      For AddBA to HE capable peers this value will be used.
 *
 * @max_tx_fragments: maximum number of tx buffers per (A)-MSDU, sum
 *      of 1 + skb_shinfo(skb)->nr_frags for each skb in the frag_list.
 *
 * @offchannel_tx_hw_queue: HW queue ID to use for offchannel TX
 *      (if %IEEE80211_HW_QUEUE_CONTROL is set)
 *
 * @radiotap_mcs_details: lists which MCS information can the HW
 *      reports, by default it is set to _MCS, _GI and _BW but doesn't
 *      include _FMT. Use %IEEE80211_RADIOTAP_MCS_HAVE_\* values, only
 *      adding _BW is supported today.
 *
 * @radiotap_vht_details: lists which VHT MCS information the HW reports,
 *      the default is _GI | _BANDWIDTH.
 *      Use the %IEEE80211_RADIOTAP_VHT_KNOWN_\* values.
 *
 * @radiotap_he: HE radiotap validity flags
 *
 * @radiotap_timestamp: Information for the radiotap timestamp field; if the
 *      @units_pos member is set to a non-negative value then the timestamp
 *      field will be added and populated from the &struct ieee80211_rx_status
 *      device_timestamp.
 * @radiotap_timestamp.units_pos: Must be set to a combination of a
 *      IEEE80211_RADIOTAP_TIMESTAMP_UNIT_* and a
 *      IEEE80211_RADIOTAP_TIMESTAMP_SPOS_* value.
 * @radiotap_timestamp.accuracy: If non-negative, fills the accuracy in the
 *      radiotap field and the accuracy known flag will be set.
 *
 * @netdev_features: netdev features to be set in each netdev created
 *      from this HW. Note that not all features are usable with mac80211,
 *      other features will be rejected during HW registration.
 *
 * @uapsd_queues: This bitmap is included in (re)association frame to indicate
 *      for each access category if it is uAPSD trigger-enabled and delivery-
 *      enabled. Use IEEE80211_WMM_IE_STA_QOSINFO_AC_* to set this bitmap.
 *      Each bit corresponds to different AC. Value '1' in specific bit means
 *      that corresponding AC is both trigger- and delivery-enabled. '0' means
 *      neither enabled.
 *
 * @uapsd_max_sp_len: maximum number of total buffered frames the WMM AP may
 *      deliver to a WMM STA during any Service Period triggered by the WMM STA.
 *      Use IEEE80211_WMM_IE_STA_QOSINFO_SP_* for correct values.
 *
 * @n_cipher_schemes: a size of an array of cipher schemes definitions.
 * @cipher_schemes: a pointer to an array of cipher scheme definitions
 *      supported by HW.
 * @max_nan_de_entries: maximum number of NAN DE functions supported by the
 *      device.
 *
 * @tx_sk_pacing_shift: Pacing shift to set on TCP sockets when frames from
 *      them are encountered. The default should typically not be changed,
 *      unless the driver has good reasons for needing more buffers.
 *
 * @weight_multiplier: Driver specific airtime weight multiplier used while
 *      refilling deficit of each TXQ.
 *
 * @max_mtu: the max mtu could be set.
 */
struct ieee80211_hw {
        struct ieee80211_conf conf;
        struct wiphy *wiphy;
        const char *rate_control_algorithm;
        void *priv;
        unsigned long flags[BITS_TO_LONGS(NUM_IEEE80211_HW_FLAGS)];
        unsigned int extra_tx_headroom;
        unsigned int extra_beacon_tailroom;
        int vif_data_size;
        int sta_data_size;
        int chanctx_data_size;
        int txq_data_size;
        u16 queues;
        u16 max_listen_interval;
        s8 max_signal;
        u8 max_rates;
        u8 max_report_rates;
        u8 max_rate_tries;
        u16 max_rx_aggregation_subframes;
        u16 max_tx_aggregation_subframes;
        u8 max_tx_fragments;
        u8 offchannel_tx_hw_queue;
        u8 radiotap_mcs_details;
        u16 radiotap_vht_details;
        struct {
                int units_pos;
                s16 accuracy;
        } radiotap_timestamp;
        netdev_features_t netdev_features;
        u8 uapsd_queues;
        u8 uapsd_max_sp_len;
        u8 n_cipher_schemes;
        const struct ieee80211_cipher_scheme *cipher_schemes;
        u8 max_nan_de_entries;
        u8 tx_sk_pacing_shift;
        u8 weight_multiplier;
        u32 max_mtu;
};

static inline bool _ieee80211_hw_check(struct ieee80211_hw *hw,
                                       enum ieee80211_hw_flags flg)
{
        return test_bit(flg, hw->flags);
}
#define ieee80211_hw_check(hw, flg)     _ieee80211_hw_check(hw, IEEE80211_HW_##flg)

static inline void _ieee80211_hw_set(struct ieee80211_hw *hw,
                                     enum ieee80211_hw_flags flg)
{
        return __set_bit(flg, hw->flags);
}
#define ieee80211_hw_set(hw, flg)       _ieee80211_hw_set(hw, IEEE80211_HW_##flg)

/**
 * struct ieee80211_scan_request - hw scan request
 *
 * @ies: pointers different parts of IEs (in req.ie)
 * @req: cfg80211 request.
 */
struct ieee80211_scan_request {
        struct ieee80211_scan_ies ies;

        /* Keep last */
        struct cfg80211_scan_request req;
};

/**
 * struct ieee80211_tdls_ch_sw_params - TDLS channel switch parameters
 *
 * @sta: peer this TDLS channel-switch request/response came from
 * @chandef: channel referenced in a TDLS channel-switch request
 * @action_code: see &enum ieee80211_tdls_actioncode
 * @status: channel-switch response status
 * @timestamp: time at which the frame was received
 * @switch_time: switch-timing parameter received in the frame
 * @switch_timeout: switch-timing parameter received in the frame
 * @tmpl_skb: TDLS switch-channel response template
 * @ch_sw_tm_ie: offset of the channel-switch timing IE inside @tmpl_skb
 */
struct ieee80211_tdls_ch_sw_params {
        struct ieee80211_sta *sta;
        struct cfg80211_chan_def *chandef;
        u8 action_code;
        u32 status;
        u32 timestamp;
        u16 switch_time;
        u16 switch_timeout;
        struct sk_buff *tmpl_skb;
        u32 ch_sw_tm_ie;
};

/**
 * 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.
 *
 * Return: The mac80211 driver hw struct of @wiphy.
 */
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, const 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_ONCE(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];
}

/**
 * ieee80211_free_txskb - free TX skb
 * @hw: the hardware
 * @skb: the skb
 *
 * Free a transmit skb. Use this function when some failure
 * to transmit happened and thus status cannot be reported.
 */
void ieee80211_free_txskb(struct ieee80211_hw *hw, struct sk_buff *skb);

/**
 * 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.
 *
 * Note that in the case that the @IEEE80211_HW_SW_CRYPTO_CONTROL flag is
 * set, mac80211 will not automatically fall back to software crypto if
 * enabling hardware crypto failed. The set_key() call may also return the
 * value 1 to permit this specific key/algorithm to be done in software.
 *
 * 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 every time 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.
 *
 * The set_default_unicast_key() call updates the default WEP key index
 * configured to the hardware for WEP encryption type. This is required
 * for devices that support offload of data packets (e.g. ARP responses).
 *
 * Mac80211 drivers should set the @NL80211_EXT_FEATURE_CAN_REPLACE_PTK0 flag
 * when they are able to replace in-use PTK keys according to the following
 * requirements:
 * 1) They do not hand over frames decrypted with the old key to
      mac80211 once the call to set_key() with command %DISABLE_KEY has been
      completed when also setting @IEEE80211_KEY_FLAG_GENERATE_IV for any key,
   2) either drop or continue to use the old key for any outgoing frames queued
      at the time of the key deletion (including re-transmits),
   3) never send out a frame queued prior to the set_key() %SET_KEY command
      encrypted with the new key and
   4) never send out a frame unencrypted when it should be encrypted.
   Mac80211 will not queue any new frames for a deleted key to the driver.
 */

/**
 * 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 issuing commands to the hardware and putting it
 * back to sleep at appropriate 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 simply supported by 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_VIF_SUPPORTS_UAPSD flag. The mode is configured through the
 * uapsd parameter 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 usually 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_VIF_BEACON_FILTER
 * interface 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.
 */

/**
 * DOC: AP support for powersaving clients
 *
 * In order to implement AP and P2P GO modes, mac80211 has support for
 * client powersaving, both "legacy" PS (PS-Poll/null data) and uAPSD.
 * There currently is no support for sAPSD.
 *
 * There is one assumption that mac80211 makes, namely that a client
 * will not poll with PS-Poll and trigger with uAPSD at the same time.
 * Both are supported, and both can be used by the same client, but
 * they can't be used concurrently by the same client. This simplifies
 * the driver code.
 *
 * The first thing to keep in mind is that there is a flag for complete
 * driver implementation: %IEEE80211_HW_AP_LINK_PS. If this flag is set,
 * mac80211 expects the driver to handle most of the state machine for
 * powersaving clients and will ignore the PM bit in incoming frames.
 * Drivers then use ieee80211_sta_ps_transition() to inform mac80211 of
 * stations' powersave transitions. In this mode, mac80211 also doesn't
 * handle PS-Poll/uAPSD.
 *
 * In the mode without %IEEE80211_HW_AP_LINK_PS, mac80211 will check the
 * PM bit in incoming frames for client powersave transitions. When a
 * station goes to sleep, we will stop transmitting to it. There is,
 * however, a race condition: a station might go to sleep while there is
 * data buffered on hardware queues. If the device has support for this
 * it will reject frames, and the driver should give the frames back to
 * mac80211 with the %IEEE80211_TX_STAT_TX_FILTERED flag set which will
 * cause mac80211 to retry the frame when the station wakes up. The
 * driver is also notified of powersave transitions by calling its
 * @sta_notify callback.
 *
 * When the station is asleep, it has three choices: it can wake up,
 * it can PS-Poll, or it can possibly start a uAPSD service period.
 * Waking up is implemented by simply transmitting all buffered (and
 * filtered) frames to the station. This is the easiest case. When
 * the station sends a PS-Poll or a uAPSD trigger frame, mac80211
 * will inform the driver of this with the @allow_buffered_frames
 * callback; this callback is optional. mac80211 will then transmit
 * the frames as usual and set the %IEEE80211_TX_CTL_NO_PS_BUFFER
 * on each frame. The last frame in the service period (or the only
 * response to a PS-Poll) also has %IEEE80211_TX_STATUS_EOSP set to
 * indicate that it ends the service period; as this frame must have
 * TX status report it also sets %IEEE80211_TX_CTL_REQ_TX_STATUS.
 * When TX status is reported for this frame, the service period is
 * marked has having ended and a new one can be started by the peer.
 *
 * Additionally, non-bufferable MMPDUs can also be transmitted by
 * mac80211 with the %IEEE80211_TX_CTL_NO_PS_BUFFER set in them.
 *
 * Another race condition can happen on some devices like iwlwifi
 * when there are frames queued for the station and it wakes up
 * or polls; the frames that are already queued could end up being
 * transmitted first instead, causing reordering and/or wrong
 * processing of the EOSP. The cause is that allowing frames to be
 * transmitted to a certain station is out-of-band communication to
 * the device. To allow this problem to be solved, the driver can
 * call ieee80211_sta_block_awake() if frames are buffered when it
 * is notified that the station went to sleep. When all these frames
 * have been filtered (see above), it must call the function again
 * to indicate that the station is no longer blocked.
 *
 * If the driver buffers frames in the driver for aggregation in any
 * way, it must use the ieee80211_sta_set_buffered() call when it is
 * notified of the station going to sleep to inform mac80211 of any
 * TIDs that have frames buffered. Note that when a station wakes up
 * this information is reset (hence the requirement to call it when
 * informed of the station going to sleep). Then, when a service

 * period starts for any reason, @release_buffered_frames is called
 * with the number of frames to be released and which TIDs they are
 * to come from. In this case, the driver is responsible for setting
 * the EOSP (for uAPSD) and MORE_DATA bits in the released frames,
 * to help the @more_data parameter is passed to tell the driver if
 * there is more data on other TIDs -- the TIDs to release frames
 * from are ignored since mac80211 doesn't know how many frames the
 * buffers for those TIDs contain.
 *
 * If the driver also implement GO mode, where absence periods may
 * shorten service periods (or abort PS-Poll responses), it must
 * filter those response frames except in the case of frames that
 * are buffered in the driver -- those must remain buffered to avoid
 * reordering. Because it is possible that no frames are released
 * in this case, the driver must call ieee80211_sta_eosp()
 * to indicate to mac80211 that the service period ended anyway.
 *
 * Finally, if frames from multiple TIDs are released from mac80211
 * but the driver might reorder them, it must clear & set the flags
 * appropriately (only the last frame may have %IEEE80211_TX_STATUS_EOSP)
 * and also take care of the EOSP and MORE_DATA bits in the frame.
 * The driver may also use ieee80211_sta_eosp() in this case.
 *
 * Note that if the driver ever buffers frames other than QoS-data
 * frames, it must take care to never send a non-QoS-data frame as
 * the last frame in a service period, adding a QoS-nulldata frame
 * after a non-QoS-data frame if needed.
 */

/**
 * DOC: HW queue control
 *
 * Before HW queue control was introduced, mac80211 only had a single static
 * assignment of per-interface AC software queues to hardware queues. This
 * was problematic for a few reasons:
 * 1) off-channel transmissions might get stuck behind other frames
 * 2) multiple virtual interfaces couldn't be handled correctly
 * 3) after-DTIM frames could get stuck behind other frames
 *
 * To solve this, hardware typically uses multiple different queues for all
 * the different usages, and this needs to be propagated into mac80211 so it
 * won't have the same problem with the software queues.
 *
 * Therefore, mac80211 now offers the %IEEE80211_HW_QUEUE_CONTROL capability
 * flag that tells it that the driver implements its own queue control. To do
 * so, the driver will set up the various queues in each &struct ieee80211_vif
 * and the offchannel queue in &struct ieee80211_hw. In response, mac80211 will
 * use those queue IDs in the hw_queue field of &struct ieee80211_tx_info and
 * if necessary will queue the frame on the right software queue that mirrors
 * the hardware queue.
 * Additionally, the driver has to then use these HW queue IDs for the queue
 * management functions (ieee80211_stop_queue() et al.)
 *
 * The driver is free to set up the queue mappings as needed, multiple virtual
 * interfaces may map to the same hardware queues if needed. The setup has to
 * happen during add_interface or change_interface callbacks. For example, a
 * driver supporting station+station and station+AP modes might decide to have
 * 10 hardware queues to handle different scenarios:
 *
 * 4 AC HW queues for 1st vif: 0, 1, 2, 3
 * 4 AC HW queues for 2nd vif: 4, 5, 6, 7
 * after-DTIM queue for AP:   8
 * off-channel queue:         9
 *
 * It would then set up the hardware like this:
 *   hw.offchannel_tx_hw_queue = 9
 *
 * and the first virtual interface that is added as follows:
 *   vif.hw_queue[IEEE80211_AC_VO] = 0
 *   vif.hw_queue[IEEE80211_AC_VI] = 1
 *   vif.hw_queue[IEEE80211_AC_BE] = 2
 *   vif.hw_queue[IEEE80211_AC_BK] = 3
 *   vif.cab_queue = 8 // if AP mode, otherwise %IEEE80211_INVAL_HW_QUEUE
 * and the second virtual interface with 4-7.
 *
 * If queue 6 gets full, for example, mac80211 would only stop the second
 * virtual interface's BE queue since virtual interface queues are per AC.
 *
 * Note that the vif.cab_queue value should be set to %IEEE80211_INVAL_HW_QUEUE
 * whenever the queue is not used (i.e. the interface is not in AP mode) if the
 * queue could potentially be shared since mac80211 will look at cab_queue when
 * a queue is stopped/woken even if the interface is not in AP mode.
 */

/**
 * 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_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) addressed to this
 *      station
 *
 * @FIF_OTHER_BSS: pass frames destined to other BSSes
 *
 * @FIF_PSPOLL: pass PS Poll frames
 *
 * @FIF_PROBE_REQ: pass probe request frames
 *
 * @FIF_MCAST_ACTION: pass multicast Action frames
 */
enum ieee80211_filter_flags {
        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,
        FIF_PROBE_REQ           = 1<<8,
        FIF_MCAST_ACTION        = 1<<9,
};

/**
 * 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, the driver must either
 *      call ieee80211_start_tx_ba_cb_irqsafe() or
 *      call ieee80211_start_tx_ba_cb_irqsafe() with status
 *      %IEEE80211_AMPDU_TX_START_DELAY_ADDBA to delay addba after
 *      ieee80211_start_tx_ba_cb_irqsafe is called, or just return the special
 *      status %IEEE80211_AMPDU_TX_START_IMMEDIATE.
 * @IEEE80211_AMPDU_TX_OPERATIONAL: TX aggregation has become operational
 * @IEEE80211_AMPDU_TX_STOP_CONT: stop TX aggregation but continue transmitting
 *      queued packets, now unaggregated. After all packets are transmitted the
 *      driver has to call ieee80211_stop_tx_ba_cb_irqsafe().
 * @IEEE80211_AMPDU_TX_STOP_FLUSH: stop TX aggregation and flush all packets,
 *      called when the station is removed. There's no need or reason to call
 *      ieee80211_stop_tx_ba_cb_irqsafe() in this case as mac80211 assumes the
 *      session is gone and removes the station.
 * @IEEE80211_AMPDU_TX_STOP_FLUSH_CONT: called when TX aggregation is stopped
 *      but the driver hasn't called ieee80211_stop_tx_ba_cb_irqsafe() yet and
 *      now the connection is dropped and the station will be removed. Drivers
 *      should clean up and drop remaining packets when this is called.
 */
enum ieee80211_ampdu_mlme_action {
        IEEE80211_AMPDU_RX_START,
        IEEE80211_AMPDU_RX_STOP,
        IEEE80211_AMPDU_TX_START,
        IEEE80211_AMPDU_TX_STOP_CONT,
        IEEE80211_AMPDU_TX_STOP_FLUSH,
        IEEE80211_AMPDU_TX_STOP_FLUSH_CONT,
        IEEE80211_AMPDU_TX_OPERATIONAL,
};

#define IEEE80211_AMPDU_TX_START_IMMEDIATE 1
#define IEEE80211_AMPDU_TX_START_DELAY_ADDBA 2

/**
 * struct ieee80211_ampdu_params - AMPDU action parameters
 *
 * @action: the ampdu action, value from %ieee80211_ampdu_mlme_action.
 * @sta: peer of this AMPDU session
 * @tid: tid of the BA session
 * @ssn: start sequence number of the session. TX/RX_STOP can pass 0. When
 *      action is set to %IEEE80211_AMPDU_RX_START the driver passes back the
 *      actual ssn value used to start the session and writes the value here.
 * @buf_size: reorder buffer size  (number of subframes). Valid only when the
 *      action is set to %IEEE80211_AMPDU_RX_START or
 *      %IEEE80211_AMPDU_TX_OPERATIONAL
 * @amsdu: indicates the peer's ability to receive A-MSDU within A-MPDU.
 *      valid when the action is set to %IEEE80211_AMPDU_TX_OPERATIONAL
 * @timeout: BA session timeout. Valid only when the action is set to
 *      %IEEE80211_AMPDU_RX_START
 */
struct ieee80211_ampdu_params {
        enum ieee80211_ampdu_mlme_action action;
        struct ieee80211_sta *sta;
        u16 tid;
        u16 ssn;
        u16 buf_size;
        bool amsdu;
        u16 timeout;
};

/**
 * enum ieee80211_frame_release_type - frame release reason
 * @IEEE80211_FRAME_RELEASE_PSPOLL: frame released for PS-Poll
 * @IEEE80211_FRAME_RELEASE_UAPSD: frame(s) released due to
 *      frame received on trigger-enabled AC
 */
enum ieee80211_frame_release_type {
        IEEE80211_FRAME_RELEASE_PSPOLL,
        IEEE80211_FRAME_RELEASE_UAPSD,
};

/**
 * enum ieee80211_rate_control_changed - flags to indicate what changed
 *
 * @IEEE80211_RC_BW_CHANGED: The bandwidth that can be used to transmit
 *      to this station changed. The actual bandwidth is in the station
 *      information -- for HT20/40 the IEEE80211_HT_CAP_SUP_WIDTH_20_40
 *      flag changes, for HT and VHT the bandwidth field changes.
 * @IEEE80211_RC_SMPS_CHANGED: The SMPS state of the station changed.
 * @IEEE80211_RC_SUPP_RATES_CHANGED: The supported rate set of this peer
 *      changed (in IBSS mode) due to discovering more information about
 *      the peer.
 * @IEEE80211_RC_NSS_CHANGED: N_SS (number of spatial streams) was changed
 *      by the peer
 */
enum ieee80211_rate_control_changed {
        IEEE80211_RC_BW_CHANGED         = BIT(0),
        IEEE80211_RC_SMPS_CHANGED       = BIT(1),
        IEEE80211_RC_SUPP_RATES_CHANGED = BIT(2),
        IEEE80211_RC_NSS_CHANGED        = BIT(3),
};

/**
 * enum ieee80211_roc_type - remain on channel type
 *
 * With the support for multi channel contexts and multi channel operations,
 * remain on channel operations might be limited/deferred/aborted by other
 * flows/operations which have higher priority (and vice versa).
 * Specifying the ROC type can be used by devices to prioritize the ROC
 * operations compared to other operations/flows.
 *
 * @IEEE80211_ROC_TYPE_NORMAL: There are no special requirements for this ROC.
 * @IEEE80211_ROC_TYPE_MGMT_TX: The remain on channel request is required
 *      for sending management frames offchannel.
 */
enum ieee80211_roc_type {
        IEEE80211_ROC_TYPE_NORMAL = 0,
        IEEE80211_ROC_TYPE_MGMT_TX,
};

/**
 * enum ieee80211_reconfig_complete_type - reconfig type
 *
 * This enum is used by the reconfig_complete() callback to indicate what
 * reconfiguration type was completed.
 *
 * @IEEE80211_RECONFIG_TYPE_RESTART: hw restart type
 *      (also due to resume() callback returning 1)
 * @IEEE80211_RECONFIG_TYPE_SUSPEND: suspend type (regardless
 *      of wowlan configuration)
 */
enum ieee80211_reconfig_type {
        IEEE80211_RECONFIG_TYPE_RESTART,
        IEEE80211_RECONFIG_TYPE_SUSPEND,
};

/**
 * 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.
 *      Must be 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.
 *
 * @suspend: Suspend the device; mac80211 itself will quiesce before and
 *      stop transmitting and doing any other configuration, and then
 *      ask the device to suspend. This is only invoked when WoWLAN is
 *      configured, otherwise the device is deconfigured completely and
 *      reconfigured at resume time.
 *      The driver may also impose special conditions under which it
 *      wants to use the "normal" suspend (deconfigure), say if it only
 *      supports WoWLAN when the device is associated. In this case, it
 *      must return 1 from this function.
 *
 * @resume: If WoWLAN was configured, this indicates that mac80211 is
 *      now resuming its operation, after this the device must be fully
 *      functional again. If this returns an error, the only way out is
 *      to also unregister the device. If it returns 1, then mac80211
 *      will also go through the regular complete restart on resume.
 *
 * @set_wakeup: Enable or disable wakeup when WoWLAN configuration is
 *      modified. The reason is that device_set_wakeup_enable() is
 *      supposed to be called when the configuration changes, not only
 *      in suspend().
 *
 * @add_interface: Called when a netdevice attached to the hardware is
 *      enabled. Because it is not called for monitor mode devices, @start
 *      and @stop must be implemented.
 *      The driver should perform any initialization it needs before
 *      the device can be enabled. The initial configuration for the
 *      interface is given in the conf parameter.
 *      The callback may refuse to add an interface by returning a
 *      negative error code (which will be seen in userspace.)
 *      Must be implemented and can sleep.
 *
 * @change_interface: Called when a netdevice changes type. This callback
 *      is optional, but only if it is supported can interface types be
 *      switched while the interface is UP. The callback may sleep.
 *      Note that while an interface is being switched, it will not be
 *      found by the interface iteration callbacks.
 *
 * @remove_interface: Notifies a driver that an interface is going down.
 *      The @stop callback is called after this if it is the last interface
 *      and no monitor interfaces are present.
 *      When all interfaces are removed, the MAC address in the hardware
 *      must be cleared so the device no longer acknowledges packets,
 *      the mac_addr member of the conf structure is, however, set to the
 *      MAC address of the device going away.
 *      Hence, this callback must be implemented. It can sleep.
 *
 * @config: Handler for configuration requests. IEEE 802.11 code calls this
 *      function to change hardware configuration, e.g., channel.
 *      This function should never fail but returns a negative error code
 *      if it does. The callback can sleep.
 *
 * @bss_info_changed: Handler for configuration requests related to BSS
 *      parameters that may vary during BSS's lifespan, and may affect low
 *      level driver (e.g. assoc/disassoc status, erp parameters).
 *      This function should not be used if no BSS has been set, unless
 *      for association indication. The @changed parameter indicates which
 *      of the bss parameters has changed when a call is made. The callback
 *      can sleep.
 *
 * @prepare_multicast: Prepare for multicast filter configuration.
 *      This callback is optional, and its return value is passed
 *      to configure_filter(). This callback must be atomic.
 *
 * @configure_filter: Configure the device's RX filter.
 *      See the section "Frame filtering" for more information.
 *      This callback must be implemented and can sleep.
 *
 * @config_iface_filter: Configure the interface's RX filter.
 *      This callback is optional and is used to configure which frames
 *      should be passed to mac80211. The filter_flags is the combination
 *      of FIF_* flags. The changed_flags is a bit mask that indicates
 *      which flags are changed.
 *      This callback can sleep.
 *
 * @set_tim: Set TIM bit. mac80211 calls this function when a TIM bit
 *      must be set or cleared for a given STA. Must be atomic.
 *
 * @set_key: See the section "Hardware crypto acceleration"
 *      This callback is only called between add_interface and
 *      remove_interface calls, i.e. while the given virtual interface
 *      is enabled.
 *      Returns a negative error code if the key can't be added.
 *      The callback can sleep.
 *
 * @update_tkip_key: See the section "Hardware crypto acceleration"
 *      This callback will be called in the context of Rx. Called for drivers
 *      which set IEEE80211_KEY_FLAG_TKIP_REQ_RX_P1_KEY.
 *      The callback must be atomic.
 *
 * @set_rekey_data: If the device supports GTK rekeying, for example while the
 *      host is suspended, it can assign this callback to retrieve the data
 *      necessary to do GTK rekeying, this is the KEK, KCK and replay counter.
 *      After rekeying was done it should (for example during resume) notify
 *      userspace of the new replay counter using ieee80211_gtk_rekey_notify().
 *
 * @set_default_unicast_key: Set the default (unicast) key index, useful for
 *      WEP when the device sends data packets autonomously, e.g. for ARP
 *      offloading. The index can be 0-3, or -1 for unsetting it.
 *
 * @hw_scan: Ask the hardware to service the scan request, no need to start
 *      the scan state machine in stack. The scan must honour the channel
 *      configuration done by the regulatory agent in the wiphy's
 *      registered bands. The hardware (or the driver) needs to make sure
 *      that power save is disabled.
 *      The @req ie/ie_len members are rewritten by mac80211 to contain the
 *      entire IEs after the SSID, so that drivers need not look at these
 *      at all but just send them after the SSID -- mac80211 includes the
 *      (extended) supported rates and HT information (where applicable).
 *      When the scan finishes, ieee80211_scan_completed() must be called;
 *      note that it also must be called when the scan cannot finish due to
 *      any error unless this callback returned a negative error code.
 *      This callback is also allowed to return the special return value 1,
 *      this indicates that hardware scan isn't desirable right now and a
 *      software scan should be done instead. A driver wishing to use this
 *      capability must ensure its (hardware) scan capabilities aren't
 *      advertised as more capable than mac80211's software scan is.
 *      The callback can sleep.
 *
 * @cancel_hw_scan: Ask the low-level tp cancel the active hw scan.
 *      The driver should ask the hardware to cancel the scan (if possible),
 *      but the scan will be completed only after the driver will call
 *      ieee80211_scan_completed().
 *      This callback is needed for wowlan, to prevent enqueueing a new
 *      scan_work after the low-level driver was already suspended.
 *      The callback can sleep.
 *
 * @sched_scan_start: Ask the hardware to start scanning repeatedly at
 *      specific intervals.  The driver must call the
 *      ieee80211_sched_scan_results() function whenever it finds results.
 *      This process will continue until sched_scan_stop is called.
 *
 * @sched_scan_stop: Tell the hardware to stop an ongoing scheduled scan.
 *      In this case, ieee80211_sched_scan_stopped() must not be called.
 *
 * @sw_scan_start: Notifier function that is called just before a software scan
 *      is started. Can be NULL, if the driver doesn't need this notification.
 *      The mac_addr parameter allows supporting NL80211_SCAN_FLAG_RANDOM_ADDR,
 *      the driver may set the NL80211_FEATURE_SCAN_RANDOM_MAC_ADDR flag if it
 *      can use this parameter. The callback can sleep.
 *
 * @sw_scan_complete: Notifier function that is called just after a
 *      software scan finished. Can be NULL, if the driver doesn't need
 *      this notification.
 *      The callback can sleep.
 *
 * @get_stats: Return low-level statistics.
 *      Returns zero if statistics are available.
 *      The callback can sleep.
 *
 * @get_key_seq: If your device implements encryption in hardware and does
 *      IV/PN assignment then this callback should be provided to read the
 *      IV/PN for the given key from hardware.
 *      The callback must be atomic.
 *
 * @set_frag_threshold: Configuration of fragmentation threshold. Assign this
 *      if the device does fragmentation by itself. Note that to prevent the
 *      stack from doing fragmentation IEEE80211_HW_SUPPORTS_TX_FRAG
 *      should be set as well.
 *      The callback can sleep.
 *
 * @set_rts_threshold: Configuration of RTS threshold (if device needs it)
 *      The callback can sleep.
 *
 * @sta_add: Notifies low level driver about addition of an associated station,
 *      AP, IBSS/WDS/mesh peer etc. This callback can sleep.
 *
 * @sta_remove: Notifies low level driver about removal of an associated
 *      station, AP, IBSS/WDS/mesh peer etc. Note that after the callback
 *      returns it isn't safe to use the pointer, not even RCU protected;
 *      no RCU grace period is guaranteed between returning here and freeing
 *      the station. See @sta_pre_rcu_remove if needed.
 *      This callback can sleep.
 *
 * @sta_add_debugfs: Drivers can use this callback to add debugfs files
 *      when a station is added to mac80211's station list. This callback
 *      should be within a CONFIG_MAC80211_DEBUGFS conditional. This
 *      callback can sleep.
 *
 * @sta_notify: Notifies low level driver about power state transition of an
 *      associated station, AP,  IBSS/WDS/mesh peer etc. For a VIF operating
 *      in AP mode, this callback will not be called when the flag
 *      %IEEE80211_HW_AP_LINK_PS is set. Must be atomic.
 *
 * @sta_set_txpwr: Configure the station tx power. This callback set the tx
 *      power for the station.
 *      This callback can sleep.
 *
 * @sta_state: Notifies low level driver about state transition of a
 *      station (which can be the AP, a client, IBSS/WDS/mesh peer etc.)
 *      This callback is mutually exclusive with @sta_add/@sta_remove.
 *      It must not fail for down transitions but may fail for transitions
 *      up the list of states. Also note that after the callback returns it
 *      isn't safe to use the pointer, not even RCU protected - no RCU grace
 *      period is guaranteed between returning here and freeing the station.
 *      See @sta_pre_rcu_remove if needed.
 *      The callback can sleep.
 *
 * @sta_pre_rcu_remove: Notify driver about station removal before RCU
 *      synchronisation. This is useful if a driver needs to have station
 *      pointers protected using RCU, it can then use this call to clear
 *      the pointers instead of waiting for an RCU grace period to elapse
 *      in @sta_state.
 *      The callback can sleep.
 *
 * @sta_rc_update: Notifies the driver of changes to the bitrates that can be
 *      used to transmit to the station. The changes are advertised with bits
 *      from &enum ieee80211_rate_control_changed and the values are reflected
 *      in the station data. This callback should only be used when the driver
 *      uses hardware rate control (%IEEE80211_HW_HAS_RATE_CONTROL) since
 *      otherwise the rate control algorithm is notified directly.
 *      Must be atomic.
 * @sta_rate_tbl_update: Notifies the driver that the rate table changed. This
 *      is only used if the configured rate control algorithm actually uses
 *      the new rate table API, and is therefore optional. Must be atomic.
 *
 * @sta_statistics: Get statistics for this station. For example with beacon
 *      filtering, the statistics kept by mac80211 might not be accurate, so
 *      let the driver pre-fill the statistics. The driver can fill most of
 *      the values (indicating which by setting the filled bitmap), but not
 *      all of them make sense - see the source for which ones are possible.
 *      Statistics that the driver doesn't fill will be filled by mac80211.
 *      The callback can sleep.
 *
 * @conf_tx: Configure TX queue parameters (EDCF (aifs, cw_min, cw_max),
 *      bursting) for a hardware TX queue.
 *      Returns a negative error code on failure.
 *      The callback can sleep.
 *
 * @get_tsf: Get the current TSF timer value from firmware/hardware. Currently,
 *      this is only used for IBSS mode BSSID merging and debugging. Is not a
 *      required function.
 *      The callback can sleep.
 *
 * @set_tsf: Set the TSF timer to the specified value in the firmware/hardware.
 *      Currently, this is only used for IBSS mode debugging. Is not a
 *      required function.
 *      The callback can sleep.
 *
 * @offset_tsf: Offset the TSF timer by the specified value in the
 *      firmware/hardware.  Preferred to set_tsf as it avoids delay between
 *      calling set_tsf() and hardware getting programmed, which will show up
 *      as TSF delay. Is not a required function.
 *      The callback can sleep.
 *
 * @reset_tsf: Reset the TSF timer and allow firmware/hardware to synchronize
 *      with other STAs in the IBSS. This is only used in IBSS mode. This
 *      function is optional if the firmware/hardware takes full care of
 *      TSF synchronization.
 *      The callback can sleep.
 *
 * @tx_last_beacon: Determine whether the last IBSS beacon was sent by us.
 *      This is needed only for IBSS mode and the result of this function is
 *      used to determine whether to reply to Probe Requests.
 *      Returns non-zero if this device sent the last beacon.
 *      The callback can sleep.
 *
 * @get_survey: Return per-channel survey information
 *
 * @rfkill_poll: Poll rfkill hardware state. If you need this, you also
 *      need to set wiphy->rfkill_poll to %true before registration,
 *      and need to call wiphy_rfkill_set_hw_state() in the callback.
 *      The callback can sleep.
 *
 * @set_coverage_class: Set slot time for given coverage class as specified
 *      in IEEE 802.11-2007 section 17.3.8.6 and modify ACK timeout
 *      accordingly; coverage class equals to -1 to enable ACK timeout
 *      estimation algorithm (dynack). To disable dynack set valid value for
 *      coverage class. This callback is not required and may sleep.
 *
 * @testmode_cmd: Implement a cfg80211 test mode command. The passed @vif may
 *      be %NULL. The callback can sleep.
 * @testmode_dump: Implement a cfg80211 test mode dump. The callback can sleep.
 *
 * @flush: Flush all pending frames from the hardware queue, making sure
 *      that the hardware queues are empty. The @queues parameter is a bitmap
 *      of queues to flush, which is useful if different virtual interfaces
 *      use different hardware queues; it may also indicate all queues.
 *      If the parameter @drop is set to %true, pending frames may be dropped.
 *      Note that vif can be NULL.
 *      The callback can sleep.
 *
 * @channel_switch: Drivers that need (or want) to offload the channel
 *      switch operation for CSAs received from the AP may implement this
 *      callback. They must then call ieee80211_chswitch_done() to indicate
 *      completion of the channel switch.
 *
 * @set_antenna: Set antenna configuration (tx_ant, rx_ant) on the device.
 *      Parameters are bitmaps of allowed antennas to use for TX/RX. Drivers may
 *      reject TX/RX mask combinations they cannot support by returning -EINVAL
 *      (also see nl80211.h @NL80211_ATTR_WIPHY_ANTENNA_TX).
 *
 * @get_antenna: Get current antenna configuration from device (tx_ant, rx_ant).
 *
 * @remain_on_channel: Starts an off-channel period on the given channel, must
 *      call back to ieee80211_ready_on_channel() when on that channel. Note
 *      that normal channel traffic is not stopped as this is intended for hw
 *      offload. Frames to transmit on the off-channel channel are transmitted
 *      normally except for the %IEEE80211_TX_CTL_TX_OFFCHAN flag. When the
 *      duration (which will always be non-zero) expires, the driver must call
 *      ieee80211_remain_on_channel_expired().
 *      Note that this callback may be called while the device is in IDLE and
 *      must be accepted in this case.
 *      This callback may sleep.
 * @cancel_remain_on_channel: Requests that an ongoing off-channel period is
 *      aborted before it expires. This callback may sleep.
 *
 * @set_ringparam: Set tx and rx ring sizes.
 *
 * @get_ringparam: Get tx and rx ring current and maximum sizes.
 *
 * @tx_frames_pending: Check if there is any pending frame in the hardware
 *      queues before entering power save.
 *
 * @set_bitrate_mask: Set a mask of rates to be used for rate control selection
 *      when transmitting a frame. Currently only legacy rates are handled.
 *      The callback can sleep.
 * @event_callback: Notify driver about any event in mac80211. See
 *      &enum ieee80211_event_type for the different types.
 *      The callback must be atomic.
 *
 * @release_buffered_frames: Release buffered frames according to the given
 *      parameters. In the case where the driver buffers some frames for
 *      sleeping stations mac80211 will use this callback to tell the driver
 *      to release some frames, either for PS-poll or uAPSD.
 *      Note that if the @more_data parameter is %false the driver must check
 *      if there are more frames on the given TIDs, and if there are more than
 *      the frames being released then it must still set the more-data bit in
 *      the frame. If the @more_data parameter is %true, then of course the
 *      more-data bit must always be set.
 *      The @tids parameter tells the driver which TIDs to release frames
 *      from, for PS-poll it will always have only a single bit set.
 *      In the case this is used for a PS-poll initiated release, the
 *      @num_frames parameter will always be 1 so code can be shared. In
 *      this case the driver must also set %IEEE80211_TX_STATUS_EOSP flag
 *      on the TX status (and must report TX status) so that the PS-poll
 *      period is properly ended. This is used to avoid sending multiple
 *      responses for a retried PS-poll frame.
 *      In the case this is used for uAPSD, the @num_frames parameter may be
 *      bigger than one, but the driver may send fewer frames (it must send
 *      at least one, however). In this case it is also responsible for
 *      setting the EOSP flag in the QoS header of the frames. Also, when the
 *      service period ends, the driver must set %IEEE80211_TX_STATUS_EOSP
 *      on the last frame in the SP. Alternatively, it may call the function
 *      ieee80211_sta_eosp() to inform mac80211 of the end of the SP.
 *      This callback must be atomic.
 * @allow_buffered_frames: Prepare device to allow the given number of frames
 *      to go out to the given station. The frames will be sent by mac80211
 *      via the usual TX path after this call. The TX information for frames
 *      released will also have the %IEEE80211_TX_CTL_NO_PS_BUFFER flag set
 *      and the last one will also have %IEEE80211_TX_STATUS_EOSP set. In case
 *      frames from multiple TIDs are released and the driver might reorder
 *      them between the TIDs, it must set the %IEEE80211_TX_STATUS_EOSP flag
 *      on the last frame and clear it on all others and also handle the EOSP
 *      bit in the QoS header correctly. Alternatively, it can also call the
 *      ieee80211_sta_eosp() function.
 *      The @tids parameter is a bitmap and tells the driver which TIDs the
 *      frames will be on; it will at most have two bits set.
 *      This callback must be atomic.
 *
 * @get_et_sset_count:  Ethtool API to get string-set count.
 *
 * @get_et_stats:  Ethtool API to get a set of u64 stats.
 *
 * @get_et_strings:  Ethtool API to get a set of strings to describe stats
 *      and perhaps other supported types of ethtool data-sets.
 *
 * @mgd_prepare_tx: Prepare for transmitting a management frame for association
 *      before associated. In multi-channel scenarios, a virtual interface is
 *      bound to a channel before it is associated, but as it isn't associated
 *      yet it need not necessarily be given airtime, in particular since any
 *      transmission to a P2P GO needs to be synchronized against the GO's
 *      powersave state. mac80211 will call this function before transmitting a
 *      management frame prior to having successfully associated to allow the
 *      driver to give it channel time for the transmission, to get a response
 *      and to be able to synchronize with the GO.
 *      For drivers that set %IEEE80211_HW_DEAUTH_NEED_MGD_TX_PREP, mac80211
 *      would also call this function before transmitting a deauthentication
 *      frame in case that no beacon was heard from the AP/P2P GO.
 *      The callback will be called before each transmission and upon return
 *      mac80211 will transmit the frame right away.
 *      If duration is greater than zero, mac80211 hints to the driver the
 *      duration for which the operation is requested.
 *      The callback is optional and can (should!) sleep.
 *
 * @mgd_protect_tdls_discover: Protect a TDLS discovery session. After sending
 *      a TDLS discovery-request, we expect a reply to arrive on the AP's
 *      channel. We must stay on the channel (no PSM, scan, etc.), since a TDLS
 *      setup-response is a direct packet not buffered by the AP.
 *      mac80211 will call this function just before the transmission of a TDLS
 *      discovery-request. The recommended period of protection is at least
 *      2 * (DTIM period).
 *      The callback is optional and can sleep.
 *
 * @add_chanctx: Notifies device driver about new channel context creation.
 *      This callback may sleep.
 * @remove_chanctx: Notifies device driver about channel context destruction.
 *      This callback may sleep.
 * @change_chanctx: Notifies device driver about channel context changes that
 *      may happen when combining different virtual interfaces on the same
 *      channel context with different settings
 *      This callback may sleep.
 * @assign_vif_chanctx: Notifies device driver about channel context being bound
 *      to vif. Possible use is for hw queue remapping.
 *      This callback may sleep.
 * @unassign_vif_chanctx: Notifies device driver about channel context being
 *      unbound from vif.
 *      This callback may sleep.
 * @switch_vif_chanctx: switch a number of vifs from one chanctx to
 *      another, as specified in the list of
 *      @ieee80211_vif_chanctx_switch passed to the driver, according
 *      to the mode defined in &ieee80211_chanctx_switch_mode.
 *      This callback may sleep.
 *
 * @start_ap: Start operation on the AP interface, this is called after all the
 *      information in bss_conf is set and beacon can be retrieved. A channel
 *      context is bound before this is called. Note that if the driver uses
 *      software scan or ROC, this (and @stop_ap) isn't called when the AP is
 *      just "paused" for scanning/ROC, which is indicated by the beacon being
 *      disabled/enabled via @bss_info_changed.
 * @stop_ap: Stop operation on the AP interface.
 *
 * @reconfig_complete: Called after a call to ieee80211_restart_hw() and
 *      during resume, when the reconfiguration has completed.
 *      This can help the driver implement the reconfiguration step (and
 *      indicate mac80211 is ready to receive frames).
 *      This callback may sleep.
 *
 * @ipv6_addr_change: IPv6 address assignment on the given interface changed.
 *      Currently, this is only called for managed or P2P client interfaces.
 *      This callback is optional; it must not sleep.
 *
 * @channel_switch_beacon: Starts a channel switch to a new channel.
 *      Beacons are modified to include CSA or ECSA IEs before calling this
 *      function. The corresponding count fields in these IEs must be
 *      decremented, and when they reach 1 the driver must call
 *      ieee80211_csa_finish(). Drivers which use ieee80211_beacon_get()
 *      get the csa counter decremented by mac80211, but must check if it is
 *      1 using ieee80211_csa_is_complete() after the beacon has been
 *      transmitted and then call ieee80211_csa_finish().
 *      If the CSA count starts as zero or 1, this function will not be called,
 *      since there won't be any time to beacon before the switch anyway.
 * @pre_channel_switch: This is an optional callback that is called
 *      before a channel switch procedure is started (ie. when a STA
 *      gets a CSA or a userspace initiated channel-switch), allowing
 *      the driver to prepare for the channel switch.
 * @post_channel_switch: This is an optional callback that is called
 *      after a channel switch procedure is completed, allowing the
 *      driver to go back to a normal configuration.
 * @abort_channel_switch: This is an optional callback that is called
 *      when channel switch procedure was completed, allowing the
 *      driver to go back to a normal configuration.
 * @channel_switch_rx_beacon: This is an optional callback that is called
 *      when channel switch procedure is in progress and additional beacon with
 *      CSA IE was received, allowing driver to track changes in count.
 * @join_ibss: Join an IBSS (on an IBSS interface); this is called after all
 *      information in bss_conf is set up and the beacon can be retrieved. A
 *      channel context is bound before this is called.
 * @leave_ibss: Leave the IBSS again.
 *
 * @get_expected_throughput: extract the expected throughput towards the
 *      specified station. The returned value is expressed in Kbps. It returns 0
 *      if the RC algorithm does not have proper data to provide.
 *
 * @get_txpower: get current maximum tx power (in dBm) based on configuration
 *      and hardware limits.
 *
 * @tdls_channel_switch: Start channel-switching with a TDLS peer. The driver
 *      is responsible for continually initiating channel-switching operations
 *      and returning to the base channel for communication with the AP. The
 *      driver receives a channel-switch request template and the location of
 *      the switch-timing IE within the template as part of the invocation.
 *      The template is valid only within the call, and the driver can
 *      optionally copy the skb for further re-use.
 * @tdls_cancel_channel_switch: Stop channel-switching with a TDLS peer. Both
 *      peers must be on the base channel when the call completes.
 * @tdls_recv_channel_switch: a TDLS channel-switch related frame (request or
 *      response) has been received from a remote peer. The driver gets
 *      parameters parsed from the incoming frame and may use them to continue
 *      an ongoing channel-switch operation. In addition, a channel-switch
 *      response template is provided, together with the location of the
 *      switch-timing IE within the template. The skb can only be used within
 *      the function call.
 *
 * @wake_tx_queue: Called when new packets have been added to the queue.
 * @sync_rx_queues: Process all pending frames in RSS queues. This is a
 *      synchronization which is needed in case driver has in its RSS queues
 *      pending frames that were received prior to the control path action
 *      currently taken (e.g. disassociation) but are not processed yet.
 *
 * @start_nan: join an existing NAN cluster, or create a new one.
 * @stop_nan: leave the NAN cluster.
 * @nan_change_conf: change NAN configuration. The data in cfg80211_nan_conf
 *      contains full new configuration and changes specify which parameters
 *      are changed with respect to the last NAN config.
 *      The driver gets both full configuration and the changed parameters since
 *      some devices may need the full configuration while others need only the
 *      changed parameters.
 * @add_nan_func: Add a NAN function. Returns 0 on success. The data in
 *      cfg80211_nan_func must not be referenced outside the scope of
 *      this call.
 * @del_nan_func: Remove a NAN function. The driver must call
 *      ieee80211_nan_func_terminated() with
 *      NL80211_NAN_FUNC_TERM_REASON_USER_REQUEST reason code upon removal.
 * @can_aggregate_in_amsdu: Called in order to determine if HW supports
 *      aggregating two specific frames in the same A-MSDU. The relation
 *      between the skbs should be symmetric and transitive. Note that while
 *      skb is always a real frame, head may or may not be an A-MSDU.
 * @get_ftm_responder_stats: Retrieve FTM responder statistics, if available.
 *      Statistics should be cumulative, currently no way to reset is provided.
 *
 * @start_pmsr: start peer measurement (e.g. FTM) (this call can sleep)
 * @abort_pmsr: abort peer measurement (this call can sleep)
 * @set_tid_config: Apply TID specific configurations. This callback may sleep.
 * @reset_tid_config: Reset TID specific configuration for the peer.
 *      This callback may sleep.
 */
struct ieee80211_ops {
        void (*tx)(struct ieee80211_hw *hw,
                   struct ieee80211_tx_control *control,
                   struct sk_buff *skb);
        int (*start)(struct ieee80211_hw *hw);
        void (*stop)(struct ieee80211_hw *hw);
#ifdef CONFIG_PM
        int (*suspend)(struct ieee80211_hw *hw, struct cfg80211_wowlan *wowlan);
        int (*resume)(struct ieee80211_hw *hw);
        void (*set_wakeup)(struct ieee80211_hw *hw, bool enabled);
#endif
        int (*add_interface)(struct ieee80211_hw *hw,
                             struct ieee80211_vif *vif);
        int (*change_interface)(struct ieee80211_hw *hw,
                                struct ieee80211_vif *vif,
                                enum nl80211_iftype new_type, bool p2p);
        void (*remove_interface)(struct ieee80211_hw *hw,
                                 struct ieee80211_vif *vif);
        int (*config)(struct ieee80211_hw *hw, u32 changed);
        void (*bss_info_changed)(struct ieee80211_hw *hw,
                                 struct ieee80211_vif *vif,
                                 struct ieee80211_bss_conf *info,
                                 u32 changed);

        int (*start_ap)(struct ieee80211_hw *hw, struct ieee80211_vif *vif);
        void (*stop_ap)(struct ieee80211_hw *hw, struct ieee80211_vif *vif);

        u64 (*prepare_multicast)(struct ieee80211_hw *hw,
                                 struct netdev_hw_addr_list *mc_list);
        void (*configure_filter)(struct ieee80211_hw *hw,
                                 unsigned int changed_flags,
                                 unsigned int *total_flags,
                                 u64 multicast);
        void (*config_iface_filter)(struct ieee80211_hw *hw,
                                    struct ieee80211_vif *vif,
                                    unsigned int filter_flags,
                                    unsigned int changed_flags);
        int (*set_tim)(struct ieee80211_hw *hw, struct ieee80211_sta *sta,
                       bool set);
        int (*set_key)(struct ieee80211_hw *hw, enum set_key_cmd cmd,
                       struct ieee80211_vif *vif, struct ieee80211_sta *sta,
                       struct ieee80211_key_conf *key);
        void (*update_tkip_key)(struct ieee80211_hw *hw,
                                struct ieee80211_vif *vif,
                                struct ieee80211_key_conf *conf,
                                struct ieee80211_sta *sta,
                                u32 iv32, u16 *phase1key);
        void (*set_rekey_data)(struct ieee80211_hw *hw,
                               struct ieee80211_vif *vif,
                               struct cfg80211_gtk_rekey_data *data);
        void (*set_default_unicast_key)(struct ieee80211_hw *hw,
                                        struct ieee80211_vif *vif, int idx);
        int (*hw_scan)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
                       struct ieee80211_scan_request *req);
        void (*cancel_hw_scan)(struct ieee80211_hw *hw,
                               struct ieee80211_vif *vif);
        int (*sched_scan_start)(struct ieee80211_hw *hw,
                                struct ieee80211_vif *vif,
                                struct cfg80211_sched_scan_request *req,
                                struct ieee80211_scan_ies *ies);
        int (*sched_scan_stop)(struct ieee80211_hw *hw,
                               struct ieee80211_vif *vif);
        void (*sw_scan_start)(struct ieee80211_hw *hw,
                              struct ieee80211_vif *vif,
                              const u8 *mac_addr);
        void (*sw_scan_complete)(struct ieee80211_hw *hw,
                                 struct ieee80211_vif *vif);
        int (*get_stats)(struct ieee80211_hw *hw,
                         struct ieee80211_low_level_stats *stats);
        void (*get_key_seq)(struct ieee80211_hw *hw,
                            struct ieee80211_key_conf *key,
                            struct ieee80211_key_seq *seq);
        int (*set_frag_threshold)(struct ieee80211_hw *hw, u32 value);
        int (*set_rts_threshold)(struct ieee80211_hw *hw, u32 value);
        int (*sta_add)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
                       struct ieee80211_sta *sta);
        int (*sta_remove)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
                          struct ieee80211_sta *sta);
#ifdef CONFIG_MAC80211_DEBUGFS
        void (*sta_add_debugfs)(struct ieee80211_hw *hw,
                                struct ieee80211_vif *vif,
                                struct ieee80211_sta *sta,
                                struct dentry *dir);
#endif
        void (*sta_notify)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
                        enum sta_notify_cmd, struct ieee80211_sta *sta);
        int (*sta_set_txpwr)(struct ieee80211_hw *hw,
                             struct ieee80211_vif *vif,
                             struct ieee80211_sta *sta);
        int (*sta_state)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
                         struct ieee80211_sta *sta,
                         enum ieee80211_sta_state old_state,
                         enum ieee80211_sta_state new_state);
        void (*sta_pre_rcu_remove)(struct ieee80211_hw *hw,
                                   struct ieee80211_vif *vif,
                                   struct ieee80211_sta *sta);
        void (*sta_rc_update)(struct ieee80211_hw *hw,
                              struct ieee80211_vif *vif,
                              struct ieee80211_sta *sta,
                              u32 changed);
        void (*sta_rate_tbl_update)(struct ieee80211_hw *hw,
                                    struct ieee80211_vif *vif,
                                    struct ieee80211_sta *sta);
        void (*sta_statistics)(struct ieee80211_hw *hw,
                               struct ieee80211_vif *vif,
                               struct ieee80211_sta *sta,
                               struct station_info *sinfo);
        int (*conf_tx)(struct ieee80211_hw *hw,
                       struct ieee80211_vif *vif, u16 ac,
                       const struct ieee80211_tx_queue_params *params);
        u64 (*get_tsf)(struct ieee80211_hw *hw, struct ieee80211_vif *vif);
        void (*set_tsf)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
                        u64 tsf);
        void (*offset_tsf)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
                           s64 offset);
        void (*reset_tsf)(struct ieee80211_hw *hw, struct ieee80211_vif *vif);
        int (*tx_last_beacon)(struct ieee80211_hw *hw);

        /**
         * @ampdu_action:
         * Perform a certain A-MPDU action.
         * The RA/TID combination determines the destination and TID we want
         * the ampdu action to be performed for. The action is defined through
         * ieee80211_ampdu_mlme_action.
         * When the action is set to %IEEE80211_AMPDU_TX_OPERATIONAL the driver
         * may neither send aggregates containing more subframes than @buf_size
         * nor send aggregates in a way that lost frames would exceed the
         * buffer size. If just limiting the aggregate size, this would be
         * possible with a buf_size of 8:
         *
         * - ``TX: 1.....7``
         * - ``RX:  2....7`` (lost frame #1)
         * - ``TX:        8..1...``
         *
         * which is invalid since #1 was now re-transmitted well past the
         * buffer size of 8. Correct ways to retransmit #1 would be:
         *
         * - ``TX:        1   or``
         * - ``TX:        18  or``
         * - ``TX:        81``
         *
         * Even ``189`` would be wrong since 1 could be lost again.
         *
         * Returns a negative error code on failure. The driver may return
         * %IEEE80211_AMPDU_TX_START_IMMEDIATE for %IEEE80211_AMPDU_TX_START
         * if the session can start immediately.
         *
         * The callback can sleep.
         */
        int (*ampdu_action)(struct ieee80211_hw *hw,
                            struct ieee80211_vif *vif,
                            struct ieee80211_ampdu_params *params);
        int (*get_survey)(struct ieee80211_hw *hw, int idx,
                struct survey_info *survey);
        void (*rfkill_poll)(struct ieee80211_hw *hw);
        void (*set_coverage_class)(struct ieee80211_hw *hw, s16 coverage_class);
#ifdef CONFIG_NL80211_TESTMODE
        int (*testmode_cmd)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
                            void *data, int len);
        int (*testmode_dump)(struct ieee80211_hw *hw, struct sk_buff *skb,
                             struct netlink_callback *cb,
                             void *data, int len);
#endif
        void (*flush)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
                      u32 queues, bool drop);
        void (*channel_switch)(struct ieee80211_hw *hw,
                               struct ieee80211_vif *vif,
                               struct ieee80211_channel_switch *ch_switch);
        int (*set_antenna)(struct ieee80211_hw *hw, u32 tx_ant, u32 rx_ant);
        int (*get_antenna)(struct ieee80211_hw *hw, u32 *tx_ant, u32 *rx_ant);

        int (*remain_on_channel)(struct ieee80211_hw *hw,
                                 struct ieee80211_vif *vif,
                                 struct ieee80211_channel *chan,
                                 int duration,
                                 enum ieee80211_roc_type type);
        int (*cancel_remain_on_channel)(struct ieee80211_hw *hw,
                                        struct ieee80211_vif *vif);
        int (*set_ringparam)(struct ieee80211_hw *hw, u32 tx, u32 rx);
        void (*get_ringparam)(struct ieee80211_hw *hw,
                              u32 *tx, u32 *tx_max, u32 *rx, u32 *rx_max);
        bool (*tx_frames_pending)(struct ieee80211_hw *hw);
        int (*set_bitrate_mask)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,