text: /* SPDX-License-Identifier: GPL-2.0-only */
  /*
   * Copyright 2002-2005, Devicescape Software, Inc.
   * Copyright 2013-2014  Intel Mobile Communications GmbH
   * Copyright(c) 2015-2017 Intel Deutschland GmbH
   * Copyright(c) 2020-2021 Intel Corporation
   */
  
  #ifndef STA_INFO_H
  #define STA_INFO_H
  
  #include <linux/list.h>
  #include <linux/types.h>
  #include <linux/if_ether.h>
  #include <linux/workqueue.h>
  #include <linux/average.h>
  #include <linux/bitfield.h>
  #include <linux/etherdevice.h>
  #include <linux/rhashtable.h>
  #include <linux/u64_stats_sync.h>
  #include "key.h"
  
  /**
   * enum ieee80211_sta_info_flags - Stations flags
   *
   * These flags are used with &struct sta_info's @flags member, but
   * only indirectly with set_sta_flag() and friends.
   *
   * @WLAN_STA_AUTH: Station is authenticated.
   * @WLAN_STA_ASSOC: Station is associated.
   * @WLAN_STA_PS_STA: Station is in power-save mode
   * @WLAN_STA_AUTHORIZED: Station is authorized to send/receive traffic.
   *	This bit is always checked so needs to be enabled for all stations
   *	when virtual port control is not in use.
   * @WLAN_STA_SHORT_PREAMBLE: Station is capable of receiving short-preamble
   *	frames.
   * @WLAN_STA_WDS: Station is one of our WDS peers.
   * @WLAN_STA_CLEAR_PS_FILT: Clear PS filter in hardware (using the
   *	IEEE80211_TX_CTL_CLEAR_PS_FILT control flag) when the next
   *	frame to this station is transmitted.
   * @WLAN_STA_MFP: Management frame protection is used with this STA.
   * @WLAN_STA_BLOCK_BA: Used to deny ADDBA requests (both TX and RX)
   *	during suspend/resume and station removal.
   * @WLAN_STA_PS_DRIVER: driver requires keeping this station in
   *	power-save mode logically to flush frames that might still
   *	be in the queues
   * @WLAN_STA_PSPOLL: Station sent PS-poll while driver was keeping
   *	station in power-save mode, reply when the driver unblocks.
   * @WLAN_STA_TDLS_PEER: Station is a TDLS peer.
   * @WLAN_STA_TDLS_PEER_AUTH: This TDLS peer is authorized to send direct
   *	packets. This means the link is enabled.
   * @WLAN_STA_TDLS_INITIATOR: We are the initiator of the TDLS link with this
   *	station.
   * @WLAN_STA_TDLS_CHAN_SWITCH: This TDLS peer supports TDLS channel-switching
   * @WLAN_STA_TDLS_OFF_CHANNEL: The local STA is currently off-channel with this
   *	TDLS peer
   * @WLAN_STA_TDLS_WIDER_BW: This TDLS peer supports working on a wider bw on
   *	the BSS base channel.
   * @WLAN_STA_UAPSD: Station requested unscheduled SP while driver was
   *	keeping station in power-save mode, reply when the driver
   *	unblocks the station.
   * @WLAN_STA_SP: Station is in a service period, so don't try to
   *	reply to other uAPSD trigger frames or PS-Poll.
   * @WLAN_STA_4ADDR_EVENT: 4-addr event was already sent for this frame.
   * @WLAN_STA_INSERTED: This station is inserted into the hash table.
   * @WLAN_STA_RATE_CONTROL: rate control was initialized for this station.
   * @WLAN_STA_TOFFSET_KNOWN: toffset calculated for this station is valid.
   * @WLAN_STA_MPSP_OWNER: local STA is owner of a mesh Peer Service Period.
   * @WLAN_STA_MPSP_RECIPIENT: local STA is recipient of a MPSP.
   * @WLAN_STA_PS_DELIVER: station woke up, but we're still blocking TX
   *	until pending frames are delivered
   * @WLAN_STA_USES_ENCRYPTION: This station was configured for encryption,
   *	so drop all packets without a key later.
   *
   * @NUM_WLAN_STA_FLAGS: number of defined flags
   */
  enum ieee80211_sta_info_flags {
  	WLAN_STA_AUTH,
  	WLAN_STA_ASSOC,
  	WLAN_STA_PS_STA,
  	WLAN_STA_AUTHORIZED,
  	WLAN_STA_SHORT_PREAMBLE,
  	WLAN_STA_WDS,
  	WLAN_STA_CLEAR_PS_FILT,
  	WLAN_STA_MFP,
  	WLAN_STA_BLOCK_BA,
  	WLAN_STA_PS_DRIVER,
  	WLAN_STA_PSPOLL,
  	WLAN_STA_TDLS_PEER,
  	WLAN_STA_TDLS_PEER_AUTH,
  	WLAN_STA_TDLS_INITIATOR,
  	WLAN_STA_TDLS_CHAN_SWITCH,
  	WLAN_STA_TDLS_OFF_CHANNEL,
  	WLAN_STA_TDLS_WIDER_BW,
  	WLAN_STA_UAPSD,
  	WLAN_STA_SP,
  	WLAN_STA_4ADDR_EVENT,
  	WLAN_STA_INSERTED,
  	WLAN_STA_RATE_CONTROL,
  	WLAN_STA_TOFFSET_KNOWN,
  	WLAN_STA_MPSP_OWNER,
  	WLAN_STA_MPSP_RECIPIENT,
  	WLAN_STA_PS_DELIVER,
  	WLAN_STA_USES_ENCRYPTION,
  
  	NUM_WLAN_STA_FLAGS,
  };
  
  #define ADDBA_RESP_INTERVAL HZ
  #define HT_AGG_MAX_RETRIES		15
  #define HT_AGG_BURST_RETRIES		3
  #define HT_AGG_RETRIES_PERIOD		(15 * HZ)
  
  #define HT_AGG_STATE_DRV_READY		0
  #define HT_AGG_STATE_RESPONSE_RECEIVED	1
  #define HT_AGG_STATE_OPERATIONAL	2
  #define HT_AGG_STATE_STOPPING		3
  #define HT_AGG_STATE_WANT_START		4
  #define HT_AGG_STATE_WANT_STOP		5
  #define HT_AGG_STATE_START_CB		6
  #define HT_AGG_STATE_STOP_CB		7
  #define HT_AGG_STATE_SENT_ADDBA		8
  
  DECLARE_EWMA(avg_signal, 10, 8)
  enum ieee80211_agg_stop_reason {
  	AGG_STOP_DECLINED,
  	AGG_STOP_LOCAL_REQUEST,
  	AGG_STOP_PEER_REQUEST,
  	AGG_STOP_DESTROY_STA,
  };
  
  /* Debugfs flags to enable/disable use of RX/TX airtime in scheduler */
  #define AIRTIME_USE_TX		BIT(0)
  #define AIRTIME_USE_RX		BIT(1)
  
  struct airtime_info {
  	u64 rx_airtime;
  	u64 tx_airtime;
  	s64 deficit;
  	atomic_t aql_tx_pending; /* Estimated airtime for frames pending */
  	u32 aql_limit_low;
  	u32 aql_limit_high;
  };
  
  void ieee80211_sta_update_pending_airtime(struct ieee80211_local *local,
  					  struct sta_info *sta, u8 ac,
  					  u16 tx_airtime, bool tx_completed);
  
  struct sta_info;
  
  /**
   * struct tid_ampdu_tx - TID aggregation information (Tx).
   *
   * @rcu_head: rcu head for freeing structure
   * @session_timer: check if we keep Tx-ing on the TID (by timeout value)
   * @addba_resp_timer: timer for peer's response to addba request
   * @pending: pending frames queue -- use sta's spinlock to protect
   * @sta: station we are attached to
   * @dialog_token: dialog token for aggregation session
   * @timeout: session timeout value to be filled in ADDBA requests
   * @tid: TID number
   * @state: session state (see above)
   * @last_tx: jiffies of last tx activity
   * @stop_initiator: initiator of a session stop
   * @tx_stop: TX DelBA frame when stopping
   * @buf_size: reorder buffer size at receiver
   * @failed_bar_ssn: ssn of the last failed BAR tx attempt
   * @bar_pending: BAR needs to be re-sent
   * @amsdu: support A-MSDU withing A-MDPU
   *
   * This structure's lifetime is managed by RCU, assignments to
   * the array holding it must hold the aggregation mutex.
   *
   * The TX path can access it under RCU lock-free if, and
   * only if, the state has the flag %HT_AGG_STATE_OPERATIONAL
   * set. Otherwise, the TX path must also acquire the spinlock
   * and re-check the state, see comments in the tx code
   * touching it.
   */
  struct tid_ampdu_tx {
  	struct rcu_head rcu_head;
  	struct timer_list session_timer;
  	struct timer_list addba_resp_timer;
  	struct sk_buff_head pending;
  	struct sta_info *sta;
  	unsigned long state;
  	unsigned long last_tx;
  	u16 timeout;
  	u8 dialog_token;
  	u8 stop_initiator;
  	bool tx_stop;
  	u16 buf_size;
  
  	u16 failed_bar_ssn;
  	bool bar_pending;
  	bool amsdu;
  	u8 tid;
  };
  
  /**
   * struct tid_ampdu_rx - TID aggregation information (Rx).
   *
   * @reorder_buf: buffer to reorder incoming aggregated MPDUs. An MPDU may be an
   *	A-MSDU with individually reported subframes.
   * @reorder_buf_filtered: bitmap indicating where there are filtered frames in
   *	the reorder buffer that should be ignored when releasing frames
   * @reorder_time: jiffies when skb was added
   * @session_timer: check if peer keeps Tx-ing on the TID (by timeout value)
   * @reorder_timer: releases expired frames from the reorder buffer.
   * @sta: station we are attached to
   * @last_rx: jiffies of last rx activity
   * @head_seq_num: head sequence number in reordering buffer.
   * @stored_mpdu_num: number of MPDUs in reordering buffer
   * @ssn: Starting Sequence Number expected to be aggregated.
   * @buf_size: buffer size for incoming A-MPDUs
   * @timeout: reset timer value (in TUs).
   * @tid: TID number
   * @rcu_head: RCU head used for freeing this struct
   * @reorder_lock: serializes access to reorder buffer, see below.
   * @auto_seq: used for offloaded BA sessions to automatically pick head_seq_and
   *	and ssn.
   * @removed: this session is removed (but might have been found due to RCU)
   * @started: this session has started (head ssn or higher was received)
   *
   * This structure's lifetime is managed by RCU, assignments to
   * the array holding it must hold the aggregation mutex.
   *
   * The @reorder_lock is used to protect the members of this
   * struct, except for @timeout, @buf_size and @dialog_token,
   * which are constant across the lifetime of the struct (the
   * dialog token being used only for debugging).
   */
  struct tid_ampdu_rx {
  	struct rcu_head rcu_head;
  	spinlock_t reorder_lock;
  	u64 reorder_buf_filtered;
  	struct sk_buff_head *reorder_buf;
  	unsigned long *reorder_time;
  	struct sta_info *sta;
  	struct timer_list session_timer;
  	struct timer_list reorder_timer;
  	unsigned long last_rx;
  	u16 head_seq_num;
  	u16 stored_mpdu_num;
  	u16 ssn;
  	u16 buf_size;
  	u16 timeout;
  	u8 tid;
  	u8 auto_seq:1,
  	   removed:1,
  	   started:1;
  };
  
  /**
   * struct sta_ampdu_mlme - STA aggregation information.
   *
   * @mtx: mutex to protect all TX data (except non-NULL assignments
   *	to tid_tx[idx], which are protected by the sta spinlock)
   *	tid_start_tx is also protected by sta->lock.
   * @tid_rx: aggregation info for Rx per TID -- RCU protected
   * @tid_rx_token: dialog tokens for valid aggregation sessions
   * @tid_rx_timer_expired: bitmap indicating on which TIDs the
   *	RX timer expired until the work for it runs
   * @tid_rx_stop_requested:  bitmap indicating which BA sessions per TID the
   *	driver requested to close until the work for it runs
   * @tid_rx_manage_offl: bitmap indicating which BA sessions were requested
   *	to be treated as started/stopped due to offloading
   * @agg_session_valid: bitmap indicating which TID has a rx BA session open on
   * @unexpected_agg: bitmap indicating which TID already sent a delBA due to
   *	unexpected aggregation related frames outside a session
   * @work: work struct for starting/stopping aggregation
   * @tid_tx: aggregation info for Tx per TID
   * @tid_start_tx: sessions where start was requested
   * @last_addba_req_time: timestamp of the last addBA request.
   * @addba_req_num: number of times addBA request has been sent.
   * @dialog_token_allocator: dialog token enumerator for each new session;
   */
  struct sta_ampdu_mlme {
  	struct mutex mtx;
  	/* rx */
  	struct tid_ampdu_rx __rcu *tid_rx[IEEE80211_NUM_TIDS];
  	u8 tid_rx_token[IEEE80211_NUM_TIDS];
  	unsigned long tid_rx_timer_expired[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
  	unsigned long tid_rx_stop_requested[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
  	unsigned long tid_rx_manage_offl[BITS_TO_LONGS(2 * IEEE80211_NUM_TIDS)];
  	unsigned long agg_session_valid[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
  	unsigned long unexpected_agg[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
  	/* tx */
  	struct work_struct work;
  	struct tid_ampdu_tx __rcu *tid_tx[IEEE80211_NUM_TIDS];
  	struct tid_ampdu_tx *tid_start_tx[IEEE80211_NUM_TIDS];
  	unsigned long last_addba_req_time[IEEE80211_NUM_TIDS];
  	u8 addba_req_num[IEEE80211_NUM_TIDS];
  	u8 dialog_token_allocator;
  };
  
  
  /* Value to indicate no TID reservation */
  #define IEEE80211_TID_UNRESERVED	0xff
  
  #define IEEE80211_FAST_XMIT_MAX_IV	18
  
  /**
   * struct ieee80211_fast_tx - TX fastpath information
   * @key: key to use for hw crypto
   * @hdr: the 802.11 header to put with the frame
   * @hdr_len: actual 802.11 header length
   * @sa_offs: offset of the SA
   * @da_offs: offset of the DA
   * @pn_offs: offset where to put PN for crypto (or 0 if not needed)
   * @band: band this will be transmitted on, for tx_info
   * @rcu_head: RCU head to free this struct
   *
   * This struct is small enough so that the common case (maximum crypto
   * header length of 8 like for CCMP/GCMP) fits into a single 64-byte
   * cache line.
   */
  struct ieee80211_fast_tx {
  	struct ieee80211_key *key;
  	u8 hdr_len;
  	u8 sa_offs, da_offs, pn_offs;
  	u8 band;
  	u8 hdr[30 + 2 + IEEE80211_FAST_XMIT_MAX_IV +
  	       sizeof(rfc1042_header)] __aligned(2);
  
  	struct rcu_head rcu_head;
  };
  
  /**
   * struct ieee80211_fast_rx - RX fastpath information
   * @dev: netdevice for reporting the SKB
   * @vif_type: (P2P-less) interface type of the original sdata (sdata->vif.type)
   * @vif_addr: interface address
   * @rfc1042_hdr: copy of the RFC 1042 SNAP header (to have in cache)
   * @control_port_protocol: control port protocol copied from sdata
   * @expected_ds_bits: from/to DS bits expected
   * @icv_len: length of the MIC if present
   * @key: bool indicating encryption is expected (key is set)
   * @internal_forward: forward froms internally on AP/VLAN type interfaces
   * @uses_rss: copy of USES_RSS hw flag
   * @da_offs: offset of the DA in the header (for header conversion)
   * @sa_offs: offset of the SA in the header (for header conversion)
   * @rcu_head: RCU head for freeing this structure
   */
  struct ieee80211_fast_rx {
  	struct net_device *dev;
  	enum nl80211_iftype vif_type;
  	u8 vif_addr[ETH_ALEN] __aligned(2);
  	u8 rfc1042_hdr[6] __aligned(2);
  	__be16 control_port_protocol;
  	__le16 expected_ds_bits;
  	u8 icv_len;
  	u8 key:1,
  	   internal_forward:1,
  	   uses_rss:1;
  	u8 da_offs, sa_offs;
  
  	struct rcu_head rcu_head;
  };
  
  /* we use only values in the range 0-100, so pick a large precision */
  DECLARE_EWMA(mesh_fail_avg, 20, 8)
  DECLARE_EWMA(mesh_tx_rate_avg, 8, 16)
  
  /**
   * struct mesh_sta - mesh STA information
   * @plink_lock: serialize access to plink fields
   * @llid: Local link ID
   * @plid: Peer link ID
   * @aid: local aid supplied by peer
   * @reason: Cancel reason on PLINK_HOLDING state
   * @plink_retries: Retries in establishment
   * @plink_state: peer link state
   * @plink_timeout: timeout of peer link
   * @plink_timer: peer link watch timer
   * @plink_sta: peer link watch timer's sta_info
   * @t_offset: timing offset relative to this host
   * @t_offset_setpoint: reference timing offset of this sta to be used when
   * 	calculating clockdrift
   * @local_pm: local link-specific power save mode
   * @peer_pm: peer-specific power save mode towards local STA
   * @nonpeer_pm: STA power save mode towards non-peer neighbors
   * @processed_beacon: set to true after peer rates and capabilities are
   *	processed
   * @connected_to_gate: true if mesh STA has a path to a mesh gate
   * @connected_to_as: true if mesh STA has a path to a authentication server
   * @fail_avg: moving percentage of failed MSDUs
   * @tx_rate_avg: moving average of tx bitrate
   */
  struct mesh_sta {
  	struct timer_list plink_timer;
  	struct sta_info *plink_sta;
  
  	s64 t_offset;
  	s64 t_offset_setpoint;
  
  	spinlock_t plink_lock;
  	u16 llid;
  	u16 plid;
  	u16 aid;
  	u16 reason;
  	u8 plink_retries;
  
  	bool processed_beacon;
  	bool connected_to_gate;
  	bool connected_to_as;
  
  	enum nl80211_plink_state plink_state;
  	u32 plink_timeout;
  
  	/* mesh power save */
  	enum nl80211_mesh_power_mode local_pm;
  	enum nl80211_mesh_power_mode peer_pm;
  	enum nl80211_mesh_power_mode nonpeer_pm;
  
  	/* moving percentage of failed MSDUs */
  	struct ewma_mesh_fail_avg fail_avg;
  	/* moving average of tx bitrate */
  	struct ewma_mesh_tx_rate_avg tx_rate_avg;
  };
  
  DECLARE_EWMA(signal, 10, 8)
  
  struct ieee80211_sta_rx_stats {
  	unsigned long packets;
  	unsigned long last_rx;
  	unsigned long num_duplicates;
  	unsigned long fragments;
  	unsigned long dropped;
  	int last_signal;
  	u8 chains;
  	s8 chain_signal_last[IEEE80211_MAX_CHAINS];
  	u32 last_rate;
  	struct u64_stats_sync syncp;
  	u64 bytes;
  	u64 msdu[IEEE80211_NUM_TIDS + 1];
  };
  
  /*
   * IEEE 802.11-2016 (10.6 "Defragmentation") recommends support for "concurrent
   * reception of at least one MSDU per access category per associated STA"
   * on APs, or "at least one MSDU per access category" on other interface types.
   *
   * This limit can be increased by changing this define, at the cost of slower
   * frame reassembly and increased memory use while fragments are pending.
   */
  #define IEEE80211_FRAGMENT_MAX 4
  
  struct ieee80211_fragment_entry {
  	struct sk_buff_head skb_list;
  	unsigned long first_frag_time;
  	u16 seq;
  	u16 extra_len;
  	u16 last_frag;
  	u8 rx_queue;
  	u8 check_sequential_pn:1, /* needed for CCMP/GCMP */
  	   is_protected:1;
  	u8 last_pn[6]; /* PN of the last fragment if CCMP was used */
  	unsigned int key_color;
  };
  
  struct ieee80211_fragment_cache {
  	struct ieee80211_fragment_entry	entries[IEEE80211_FRAGMENT_MAX];
  	unsigned int next;
  };
  
  /*
   * The bandwidth threshold below which the per-station CoDel parameters will be
   * scaled to be more lenient (to prevent starvation of slow stations). This
   * value will be scaled by the number of active stations when it is being
   * applied.
   */
  #define STA_SLOW_THRESHOLD 6000 /* 6 Mbps */
  
  /**
   * struct sta_info - STA information
   *
   * This structure collects information about a station that
   * mac80211 is communicating with.
   *
   * @list: global linked list entry
   * @free_list: list entry for keeping track of stations to free
   * @hash_node: hash node for rhashtable
   * @addr: station's MAC address - duplicated from public part to
   *	let the hash table work with just a single cacheline
   * @local: pointer to the global information
   * @sdata: virtual interface this station belongs to
   * @ptk: peer keys negotiated with this station, if any
   * @ptk_idx: last installed peer key index
   * @gtk: group keys negotiated with this station, if any
   * @rate_ctrl: rate control algorithm reference
   * @rate_ctrl_lock: spinlock used to protect rate control data
   *	(data inside the algorithm, so serializes calls there)
   * @rate_ctrl_priv: rate control private per-STA pointer
   * @lock: used for locking all fields that require locking, see comments
   *	in the header file.
   * @drv_deliver_wk: used for delivering frames after driver PS unblocking
   * @listen_interval: listen interval of this station, when we're acting as AP
   * @_flags: STA flags, see &enum ieee80211_sta_info_flags, do not use directly
   * @ps_lock: used for powersave (when mac80211 is the AP) related locking
   * @ps_tx_buf: buffers (per AC) of frames to transmit to this station
   *	when it leaves power saving state or polls
   * @tx_filtered: buffers (per AC) of frames we already tried to
   *	transmit but were filtered by hardware due to STA having
   *	entered power saving state, these are also delivered to
   *	the station when it leaves powersave or polls for frames
   * @driver_buffered_tids: bitmap of TIDs the driver has data buffered on
   * @txq_buffered_tids: bitmap of TIDs that mac80211 has txq data buffered on
   * @assoc_at: clock boottime (in ns) of last association
   * @last_connected: time (in seconds) when a station got connected
   * @last_seq_ctrl: last received seq/frag number from this STA (per TID
   *	plus one for non-QoS frames)
   * @tid_seq: per-TID sequence numbers for sending to this STA
   * @airtime: per-AC struct airtime_info describing airtime statistics for this
   *	station
   * @airtime_weight: station weight for airtime fairness calculation purposes
   * @ampdu_mlme: A-MPDU state machine state
   * @mesh: mesh STA information
   * @debugfs_dir: debug filesystem directory dentry
   * @dead: set to true when sta is unlinked
   * @removed: set to true when sta is being removed from sta_list
   * @uploaded: set to true when sta is uploaded to the driver
   * @sta: station information we share with the driver
   * @sta_state: duplicates information about station state (for debug)
   * @rcu_head: RCU head used for freeing this station struct
   * @cur_max_bandwidth: maximum bandwidth to use for TX to the station,
   *	taken from HT/VHT capabilities or VHT operating mode notification
   * @known_smps_mode: the smps_mode the client thinks we are in. Relevant for
   *	AP only.
   * @cipher_scheme: optional cipher scheme for this station
   * @cparams: CoDel parameters for this station.
   * @reserved_tid: reserved TID (if any, otherwise IEEE80211_TID_UNRESERVED)
   * @fast_tx: TX fastpath information
   * @fast_rx: RX fastpath information
   * @tdls_chandef: a TDLS peer can have a wider chandef that is compatible to
   *	the BSS one.
   * @tx_stats: TX statistics
   * @tx_stats.packets: # of packets transmitted
   * @tx_stats.bytes: # of bytes in all packets transmitted
   * @tx_stats.last_rate: last TX rate
   * @tx_stats.msdu: # of transmitted MSDUs per TID
   * @rx_stats: RX statistics
   * @rx_stats_avg: averaged RX statistics
   * @rx_stats_avg.signal: averaged signal
   * @rx_stats_avg.chain_signal: averaged per-chain signal
   * @pcpu_rx_stats: per-CPU RX statistics, assigned only if the driver needs
   *	this (by advertising the USES_RSS hw flag)
   * @status_stats: TX status statistics
   * @status_stats.filtered: # of filtered frames
   * @status_stats.retry_failed: # of frames that failed after retry
   * @status_stats.retry_count: # of retries attempted
   * @status_stats.lost_packets: # of lost packets
   * @status_stats.last_pkt_time: timestamp of last ACKed packet
   * @status_stats.msdu_retries: # of MSDU retries
   * @status_stats.msdu_failed: # of failed MSDUs
   * @status_stats.last_ack: last ack timestamp (jiffies)
   * @status_stats.last_ack_signal: last ACK signal
   * @status_stats.ack_signal_filled: last ACK signal validity
   * @status_stats.avg_ack_signal: average ACK signal
   * @frags: fragment cache
   */
  struct sta_info {
  	/* General information, mostly static */
  	struct list_head list, free_list;
  	struct rcu_head rcu_head;
  	struct rhlist_head hash_node;
  	u8 addr[ETH_ALEN];
  	struct ieee80211_local *local;
  	struct ieee80211_sub_if_data *sdata;
  	struct ieee80211_key __rcu *gtk[NUM_DEFAULT_KEYS +
  					NUM_DEFAULT_MGMT_KEYS +
  					NUM_DEFAULT_BEACON_KEYS];
  	struct ieee80211_key __rcu *ptk[NUM_DEFAULT_KEYS];
  	u8 ptk_idx;
  	struct rate_control_ref *rate_ctrl;
  	void *rate_ctrl_priv;
  	spinlock_t rate_ctrl_lock;
  	spinlock_t lock;
  
  	struct ieee80211_fast_tx __rcu *fast_tx;
  	struct ieee80211_fast_rx __rcu *fast_rx;
  	struct ieee80211_sta_rx_stats __percpu *pcpu_rx_stats;
  
  #ifdef CONFIG_MAC80211_MESH
  	struct mesh_sta *mesh;
  #endif
  
  	struct work_struct drv_deliver_wk;
  
  	u16 listen_interval;
  
  	bool dead;
  	bool removed;
  
  	bool uploaded;
  
  	enum ieee80211_sta_state sta_state;
  
  	/* use the accessors defined below */
  	unsigned long _flags;
  
  	/* STA powersave lock and frame queues */
  	spinlock_t ps_lock;
  	struct sk_buff_head ps_tx_buf[IEEE80211_NUM_ACS];
  	struct sk_buff_head tx_filtered[IEEE80211_NUM_ACS];
  	unsigned long driver_buffered_tids;
  	unsigned long txq_buffered_tids;
  
  	u64 assoc_at;
  	long last_connected;
  
  	/* Updated from RX path only, no locking requirements */
  	struct ieee80211_sta_rx_stats rx_stats;
  	struct {
  		struct ewma_signal signal;
  		struct ewma_signal chain_signal[IEEE80211_MAX_CHAINS];
  	} rx_stats_avg;
  
  	/* Plus 1 for non-QoS frames */
  	__le16 last_seq_ctrl[IEEE80211_NUM_TIDS + 1];
  
  	/* Updated from TX status path only, no locking requirements */
  	struct {
  		unsigned long filtered;
  		unsigned long retry_failed, retry_count;
  		unsigned int lost_packets;
  		unsigned long last_pkt_time;
  		u64 msdu_retries[IEEE80211_NUM_TIDS + 1];
  		u64 msdu_failed[IEEE80211_NUM_TIDS + 1];
  		unsigned long last_ack;
  		s8 last_ack_signal;
  		bool ack_signal_filled;
  		struct ewma_avg_signal avg_ack_signal;
  	} status_stats;
  
  	/* Updated from TX path only, no locking requirements */
  	struct {
  		u64 packets[IEEE80211_NUM_ACS];
  		u64 bytes[IEEE80211_NUM_ACS];
  		struct ieee80211_tx_rate last_rate;
  		struct rate_info last_rate_info;
  		u64 msdu[IEEE80211_NUM_TIDS + 1];
  	} tx_stats;
  	u16 tid_seq[IEEE80211_QOS_CTL_TID_MASK + 1];
  
  	struct airtime_info airtime[IEEE80211_NUM_ACS];
  	u16 airtime_weight;
  
  	/*
  	 * Aggregation information, locked with lock.
  	 */
  	struct sta_ampdu_mlme ampdu_mlme;
  
  #ifdef CONFIG_MAC80211_DEBUGFS
  	struct dentry *debugfs_dir;
  #endif
  
  	enum ieee80211_sta_rx_bandwidth cur_max_bandwidth;
  
  	enum ieee80211_smps_mode known_smps_mode;
  	const struct ieee80211_cipher_scheme *cipher_scheme;
  
  	struct codel_params cparams;
  
  	u8 reserved_tid;
  
  	struct cfg80211_chan_def tdls_chandef;
  
  	struct ieee80211_fragment_cache frags;
  
  	/* keep last! */
  	struct ieee80211_sta sta;
  };
  
  static inline enum nl80211_plink_state sta_plink_state(struct sta_info *sta)
  {
  #ifdef CONFIG_MAC80211_MESH
  	return sta->mesh->plink_state;
  #endif
  	return NL80211_PLINK_LISTEN;
  }
  
  static inline void set_sta_flag(struct sta_info *sta,
  				enum ieee80211_sta_info_flags flag)
  {
  	WARN_ON(flag == WLAN_STA_AUTH ||
  		flag == WLAN_STA_ASSOC ||
  		flag == WLAN_STA_AUTHORIZED);
  	set_bit(flag, &sta->_flags);
  }
  
  static inline void clear_sta_flag(struct sta_info *sta,
  				  enum ieee80211_sta_info_flags flag)
  {
  	WARN_ON(flag == WLAN_STA_AUTH ||
  		flag == WLAN_STA_ASSOC ||
  		flag == WLAN_STA_AUTHORIZED);
  	clear_bit(flag, &sta->_flags);
  }
  
  static inline int test_sta_flag(struct sta_info *sta,
  				enum ieee80211_sta_info_flags flag)
  {
  	return test_bit(flag, &sta->_flags);
  }
  
  static inline int test_and_clear_sta_flag(struct sta_info *sta,
  					  enum ieee80211_sta_info_flags flag)
  {
  	WARN_ON(flag == WLAN_STA_AUTH ||
  		flag == WLAN_STA_ASSOC ||
  		flag == WLAN_STA_AUTHORIZED);
  	return test_and_clear_bit(flag, &sta->_flags);
  }
  
  static inline int test_and_set_sta_flag(struct sta_info *sta,
  					enum ieee80211_sta_info_flags flag)
  {
  	WARN_ON(flag == WLAN_STA_AUTH ||
  		flag == WLAN_STA_ASSOC ||
  		flag == WLAN_STA_AUTHORIZED);
  	return test_and_set_bit(flag, &sta->_flags);
  }
  
  int sta_info_move_state(struct sta_info *sta,
  			enum ieee80211_sta_state new_state);
  
  static inline void sta_info_pre_move_state(struct sta_info *sta,
  					   enum ieee80211_sta_state new_state)
  {
  	int ret;
  
  	WARN_ON_ONCE(test_sta_flag(sta, WLAN_STA_INSERTED));
  
  	ret = sta_info_move_state(sta, new_state);
  	WARN_ON_ONCE(ret);
  }
  
  
  void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
  			     struct tid_ampdu_tx *tid_tx);
  
  static inline struct tid_ampdu_tx *
  rcu_dereference_protected_tid_tx(struct sta_info *sta, int tid)
  {
  	return rcu_dereference_protected(sta->ampdu_mlme.tid_tx[tid],
  					 lockdep_is_held(&sta->lock) ||
  					 lockdep_is_held(&sta->ampdu_mlme.mtx));
  }
  
  /* Maximum number of frames to buffer per power saving station per AC */
  #define STA_MAX_TX_BUFFER	64
  
  /* Minimum buffered frame expiry time. If STA uses listen interval that is
   * smaller than this value, the minimum value here is used instead. */
  #define STA_TX_BUFFER_EXPIRE (10 * HZ)
  
  /* How often station data is cleaned up (e.g., expiration of buffered frames)
   */
  #define STA_INFO_CLEANUP_INTERVAL (10 * HZ)
  
  struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
  					 const u8 *addr);
  
  /*
   * Get a STA info, must be under RCU read lock.
   */
  struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
  			      const u8 *addr);
  
  struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
  				  const u8 *addr);
  
  /* user must hold sta_mtx or be in RCU critical section */
  struct sta_info *sta_info_get_by_addrs(struct ieee80211_local *local,
  				       const u8 *sta_addr, const u8 *vif_addr);
  
  #define for_each_sta_info(local, _addr, _sta, _tmp)			\
  	rhl_for_each_entry_rcu(_sta, _tmp,				\
  			       sta_info_hash_lookup(local, _addr), hash_node)
  
  /*
   * Get STA info by index, BROKEN!
   */
  struct sta_info *sta_info_get_by_idx(struct ieee80211_sub_if_data *sdata,
  				     int idx);
  /*
   * Create a new STA info, caller owns returned structure
   * until sta_info_insert().
   */
  struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
  				const u8 *addr, gfp_t gfp);
  
  void sta_info_free(struct ieee80211_local *local, struct sta_info *sta);
  
  /*
   * Insert STA info into hash table/list, returns zero or a
   * -EEXIST if (if the same MAC address is already present).
   *
   * Calling the non-rcu version makes the caller relinquish,
   * the _rcu version calls read_lock_rcu() and must be called
   * without it held.
   */
  int sta_info_insert(struct sta_info *sta);
  int sta_info_insert_rcu(struct sta_info *sta) __acquires(RCU);
  
  int __must_check __sta_info_destroy(struct sta_info *sta);
  int sta_info_destroy_addr(struct ieee80211_sub_if_data *sdata,
  			  const u8 *addr);
  int sta_info_destroy_addr_bss(struct ieee80211_sub_if_data *sdata,
  			      const u8 *addr);
  
  void sta_info_recalc_tim(struct sta_info *sta);
  
  int sta_info_init(struct ieee80211_local *local);
  void sta_info_stop(struct ieee80211_local *local);
  
  /**
   * __sta_info_flush - flush matching STA entries from the STA table
   *
   * Returns the number of removed STA entries.
   *
   * @sdata: sdata to remove all stations from
   * @vlans: if the given interface is an AP interface, also flush VLANs
   */
  int __sta_info_flush(struct ieee80211_sub_if_data *sdata, bool vlans);
  
  /**
   * sta_info_flush - flush matching STA entries from the STA table
   *
   * Returns the number of removed STA entries.
   *
   * @sdata: sdata to remove all stations from
   */
  static inline int sta_info_flush(struct ieee80211_sub_if_data *sdata)
  {
  	return __sta_info_flush(sdata, false);
  }
  
  void sta_set_rate_info_tx(struct sta_info *sta,
  			  const struct ieee80211_tx_rate *rate,
  			  struct rate_info *rinfo);
  void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo,
  		   bool tidstats);
  
  u32 sta_get_expected_throughput(struct sta_info *sta);
  
  void ieee80211_sta_expire(struct ieee80211_sub_if_data *sdata,
  			  unsigned long exp_time);
  u8 sta_info_tx_streams(struct sta_info *sta);
  
  void ieee80211_sta_ps_deliver_wakeup(struct sta_info *sta);
  void ieee80211_sta_ps_deliver_poll_response(struct sta_info *sta);
  void ieee80211_sta_ps_deliver_uapsd(struct sta_info *sta);
  
  unsigned long ieee80211_sta_last_active(struct sta_info *sta);
  
  enum sta_stats_type {
  	STA_STATS_RATE_TYPE_INVALID = 0,
  	STA_STATS_RATE_TYPE_LEGACY,
  	STA_STATS_RATE_TYPE_HT,
  	STA_STATS_RATE_TYPE_VHT,
  	STA_STATS_RATE_TYPE_HE,
  	STA_STATS_RATE_TYPE_S1G,
  };
  
  #define STA_STATS_FIELD_HT_MCS		GENMASK( 7,  0)
  #define STA_STATS_FIELD_LEGACY_IDX	GENMASK( 3,  0)
  #define STA_STATS_FIELD_LEGACY_BAND	GENMASK( 7,  4)
  #define STA_STATS_FIELD_VHT_MCS		GENMASK( 3,  0)
  #define STA_STATS_FIELD_VHT_NSS		GENMASK( 7,  4)
  #define STA_STATS_FIELD_HE_MCS		GENMASK( 3,  0)
  #define STA_STATS_FIELD_HE_NSS		GENMASK( 7,  4)
  #define STA_STATS_FIELD_BW		GENMASK(11,  8)
  #define STA_STATS_FIELD_SGI		GENMASK(12, 12)
  #define STA_STATS_FIELD_TYPE		GENMASK(15, 13)
  #define STA_STATS_FIELD_HE_RU		GENMASK(18, 16)
  #define STA_STATS_FIELD_HE_GI		GENMASK(20, 19)
  #define STA_STATS_FIELD_HE_DCM		GENMASK(21, 21)
  
  #define STA_STATS_FIELD(_n, _v)		FIELD_PREP(STA_STATS_FIELD_ ## _n, _v)
  #define STA_STATS_GET(_n, _v)		FIELD_GET(STA_STATS_FIELD_ ## _n, _v)
  
  #define STA_STATS_RATE_INVALID		0
  
  static inline u32 sta_stats_encode_rate(struct ieee80211_rx_status *s)
  {
  	u32 r;
  
  	r = STA_STATS_FIELD(BW, s->bw);
  
  	if (s->enc_flags & RX_ENC_FLAG_SHORT_GI)
  		r |= STA_STATS_FIELD(SGI, 1);
  
  	switch (s->encoding) {
  	case RX_ENC_VHT:
  		r |= STA_STATS_FIELD(TYPE, STA_STATS_RATE_TYPE_VHT);
  		r |= STA_STATS_FIELD(VHT_NSS, s->nss);
  		r |= STA_STATS_FIELD(VHT_MCS, s->rate_idx);
  		break;
  	case RX_ENC_HT:
  		r |= STA_STATS_FIELD(TYPE, STA_STATS_RATE_TYPE_HT);
  		r |= STA_STATS_FIELD(HT_MCS, s->rate_idx);
  		break;
  	case RX_ENC_LEGACY:
  		r |= STA_STATS_FIELD(TYPE, STA_STATS_RATE_TYPE_LEGACY);
  		r |= STA_STATS_FIELD(LEGACY_BAND, s->band);
  		r |= STA_STATS_FIELD(LEGACY_IDX, s->rate_idx);
  		break;
  	case RX_ENC_HE:
  		r |= STA_STATS_FIELD(TYPE, STA_STATS_RATE_TYPE_HE);
  		r |= STA_STATS_FIELD(HE_NSS, s->nss);
  		r |= STA_STATS_FIELD(HE_MCS, s->rate_idx);
  		r |= STA_STATS_FIELD(HE_GI, s->he_gi);
  		r |= STA_STATS_FIELD(HE_RU, s->he_ru);
  		r |= STA_STATS_FIELD(HE_DCM, s->he_dcm);
  		break;
  	default:
  		WARN_ON(1);
  		return STA_STATS_RATE_INVALID;
  	}
  
  	return r;
  }
  
  #endif /* STA_INFO_H */
  