mac80211.h - Linux Wireless

This kerneldoc is updated daily based on the wireless-2.6 everything branch.

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.

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!

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.

Frame format

As a general rule, when frames are passed between mac80211 and the driver, they start with the IEEE 802.11 header and include the same octets that are sent over the air except for the FCS which should be calculated by the hardware.

There are, however, various exceptions to this rule for advanced features:

The first exception is for hardware encryption and decryption offload where the IV/ICV may or may not be generated in hardware.

Secondly, when the hardware handles fragmentation, the frame handed to the driver from mac80211 is the MSDU, not the MPDU.

Finally, for received frames, the driver is able to indicate that it has filled a radiotap header and put that in front of the frame; if it does not do so then mac80211 may add this under certain circumstances.

enum ieee80211_max_queues

enum ieee80211_max_queues {
IEEE80211_MAX_QUEUES
};

Constants

IEEE80211_MAX_QUEUES: Maximum number of regular device queues.

struct ieee80211_tx_queue_params - transmit queue configuration

struct ieee80211_tx_queue_params {
u16 txop;
u16 cw_min;
u16 cw_max;
u8 aifs;
};

Members

txop: maximum burst time in units of 32 usecs, 0 meaning disabled
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]
aifs: arbitration interframe space [0..255]

Description

The information provided in this structure is required for QoS transmit queue configuration. Cf. IEEE 802.11 7.3.2.29.

struct ieee80211_tx_queue_stats - transmit queue statistics

struct ieee80211_tx_queue_stats {
unsigned int len;
unsigned int limit;
unsigned int count;
};

Members

len: number of packets in queue
limit: queue length limit
count: number of frames sent

enum ieee80211_bss_change

enum ieee80211_bss_change {
BSS_CHANGED_ASSOC,
BSS_CHANGED_ERP_CTS_PROT,
BSS_CHANGED_ERP_PREAMBLE,
BSS_CHANGED_ERP_SLOT,
BSS_CHANGED_HT,
BSS_CHANGED_BASIC_RATES,
BSS_CHANGED_BEACON_INT,
BSS_CHANGED_BSSID,
BSS_CHANGED_BEACON,
BSS_CHANGED_BEACON_ENABLED
};

Constants

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)

Description

These flags are used with the bss_info_changed callback to indicate which BSS parameter changed.

struct ieee80211_bss_conf - holds the BSS's changing parameters

struct ieee80211_bss_conf {
const u8 * bssid;
bool assoc;
u16 aid;
bool use_cts_prot;
bool use_short_preamble;
bool use_short_slot;
bool enable_beacon;
u8 dtim_period;
u16 beacon_int;
u16 assoc_capability;
u64 timestamp;
u32 basic_rates;
u16 ht_operation_mode;
};

Members

bssid: The BSSID for this BSS
assoc: association status
aid: association ID number, valid only when assoc is true
use_cts_prot: use CTS protection
use_short_preamble: use 802.11b short preamble; if the hardware cannot handle this it must set the IEEE80211_HW_2GHZ_SHORT_PREAMBLE_INCAPABLE hardware flag
use_short_slot: use short slot time (only relevant for ERP); if the hardware cannot handle this it must set the IEEE80211_HW_2GHZ_SHORT_SLOT_INCAPABLE hardware flag
enable_beacon: whether beaconing should be enabled or not
dtim_period: num of beacons before the next DTIM, for PSM
beacon_int: beacon interval
assoc_capability: capabilities taken from assoc resp
timestamp: beacon timestamp
basic_rates: bitmap of basic rates, each bit stands for an index into the rate table configured by the driver in the current band.
ht_operation_mode: HT operation mode (like in struct ieee80211_ht_info). This field is only valid when the channel type is one of the HT types.

Description

This structure keeps information about a BSS (and an association to that BSS) that can change during the lifetime of the BSS.

enum mac80211_tx_control_flags

enum mac80211_tx_control_flags {
IEEE80211_TX_CTL_REQ_TX_STATUS,
IEEE80211_TX_CTL_ASSIGN_SEQ,
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_CTL_INJECTED,
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_INTFL_RCALGO,
IEEE80211_TX_INTFL_NEED_TXPROCESSING,
IEEE80211_TX_INTFL_RETRIED,
IEEE80211_TX_INTFL_DONT_ENCRYPT
};

Constants

IEEE80211_TX_CTL_REQ_TX_STATUS: request 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.
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_RCALGO: mac80211 internal flag, do not test or set this flag in the driver; indicates that the rate control algorithm was used and should be notified of TX status
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

Description

These flags are used with the flags member of ieee80211_tx_info.

enum mac80211_rate_control_flags

enum mac80211_rate_control_flags {
IEEE80211_TX_RC_USE_RTS_CTS,
IEEE80211_TX_RC_USE_CTS_PROTECT,
IEEE80211_TX_RC_USE_SHORT_PREAMBLE,
IEEE80211_TX_RC_MCS,
IEEE80211_TX_RC_GREEN_FIELD,
IEEE80211_TX_RC_40_MHZ_WIDTH,
IEEE80211_TX_RC_DUP_DATA,
IEEE80211_TX_RC_SHORT_GI
};

Constants

IEEE80211_TX_RC_USE_RTS_CTS: Use RTS/CTS exchange for this rate.
IEEE80211_TX_RC_USE_CTS_PROTECT: CTS-to-self protection is required. This is set if the current BSS requires ERP protection.
IEEE80211_TX_RC_USE_SHORT_PREAMBLE: Use short preamble.
IEEE80211_TX_RC_MCS: HT rate.
IEEE80211_TX_RC_GREEN_FIELD: Indicates whether this rate should be used in Greenfield mode.
IEEE80211_TX_RC_40_MHZ_WIDTH: Indicates if the Channel Width should be 40 MHz.
IEEE80211_TX_RC_DUP_DATA: The frame should be transmitted on both of the adjacent 20 MHz channels, if the current channel type is NL80211_CHAN_HT40MINUS or NL80211_CHAN_HT40PLUS.
IEEE80211_TX_RC_SHORT_GI: Short Guard interval should be used for this rate.

Description

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.

struct ieee80211_tx_rate - rate selection/status

struct ieee80211_tx_rate {
s8 idx;
u8 count;
u8 flags;
};

Members

idx: rate index to attempt to send with
count: number of tries in this rate before going to the next rate
flags: rate control flags (enum mac80211_rate_control_flags)

Description

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 - skb transmit information

struct ieee80211_tx_info {
u32 flags;
u8 band;
u8 antenna_sel_tx;
u8 pad[2];
union {unnamed_union};
};

Members

flags: transmit info flags, defined above
band: the band to transmit on (use for checking for races)
antenna_sel_tx: antenna to use, 0 for automatic diversity
pad[2]: padding, ignore
{unnamed_union}: anonymous

Description

This structure is placed in skb->cb for three uses: (1) mac80211 TX control - mac80211 tells the driver what to do (2) driver internal use (if applicable) (3) TX status information - driver tells mac80211 what happened
The TX control's sta pointer is only valid during the ->tx call, it may be NULL.

ieee80211_tx_info_clear_status - clear TX status

void ieee80211_tx_info_clear_status (struct ieee80211_tx_info * info)

Arguments

info: The struct ieee80211_tx_info to be cleared.

Description

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.

enum mac80211_rx_flags

enum mac80211_rx_flags {
RX_FLAG_MMIC_ERROR,
RX_FLAG_DECRYPTED,
RX_FLAG_RADIOTAP,
RX_FLAG_MMIC_STRIPPED,
RX_FLAG_IV_STRIPPED,
RX_FLAG_FAILED_FCS_CRC,
RX_FLAG_FAILED_PLCP_CRC,
RX_FLAG_TSFT,
RX_FLAG_SHORTPRE,
RX_FLAG_HT,
RX_FLAG_40MHZ,
RX_FLAG_SHORT_GI
};

Constants

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_RADIOTAP: This frame starts with a radiotap header.
RX_FLAG_MMIC_STRIPPED: the Michael MIC is stripped off this frame, verification has been done by the hardware.
RX_FLAG_IV_STRIPPED: The IV/ICV are stripped from this frame. If this flag is set, the stack cannot do any replay detection hence the driver or hardware will have to do that.
RX_FLAG_FAILED_FCS_CRC: Set this flag if the FCS check failed on the frame.
RX_FLAG_FAILED_PLCP_CRC: Set this flag if the PCLP check failed on the frame.
RX_FLAG_TSFT: The timestamp passed in the RX status (mactime field) is valid. This is useful in monitor mode and necessary for beacon frames to enable IBSS merging.
RX_FLAG_SHORTPRE: Short preamble was used for this frame
RX_FLAG_HT: HT MCS was used and rate_idx is MCS index
RX_FLAG_40MHZ: HT40 (40 MHz) was used
RX_FLAG_SHORT_GI: Short guard interval was used

Description

These flags are used with the flag member of struct ieee80211_rx_status.

struct ieee80211_rx_status - receive status

struct ieee80211_rx_status {
u64 mactime;
enum ieee80211_band band;
int freq;
int signal;
int noise;
int qual;
int antenna;
int rate_idx;
int flag;
};

Members

mactime: value in microseconds of the 64-bit Time Synchronization Function (TSF) timer when the first data symbol (MPDU) arrived at the hardware.
band: the active band when this frame was received
freq: frequency the radio was tuned to when receiving this frame, in MHz
signal: signal strength when receiving this frame, either in dBm, in dB or unspecified depending on the hardware capabilities flags IEEE80211_HW_SIGNAL_*
noise: noise when receiving this frame, in dBm.
qual: overall signal quality indication, in percent (0-100).
antenna: antenna used
rate_idx: index of data rate into band's supported rates or MCS index if HT rates are use (RX_FLAG_HT)
flag: RX_FLAG_*

Description

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).

enum ieee80211_conf_flags

enum ieee80211_conf_flags {
IEEE80211_CONF_RADIOTAP,
IEEE80211_CONF_PS,
IEEE80211_CONF_IDLE
};

Constants

IEEE80211_CONF_RADIOTAP: add radiotap header at receive time (if supported)
IEEE80211_CONF_PS: Enable 802.11 power save mode (managed mode only)
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.

Description

Flags to define PHY configuration options

enum ieee80211_conf_changed

enum ieee80211_conf_changed {
_IEEE80211_CONF_CHANGE_RADIO_ENABLED,
IEEE80211_CONF_CHANGE_LISTEN_INTERVAL,
IEEE80211_CONF_CHANGE_RADIOTAP,
IEEE80211_CONF_CHANGE_PS,
IEEE80211_CONF_CHANGE_POWER,
IEEE80211_CONF_CHANGE_CHANNEL,
IEEE80211_CONF_CHANGE_RETRY_LIMITS,
IEEE80211_CONF_CHANGE_IDLE
};

Constants

_IEEE80211_CONF_CHANGE_RADIO_ENABLED: DEPRECATED
IEEE80211_CONF_CHANGE_LISTEN_INTERVAL: the listen interval changed
IEEE80211_CONF_CHANGE_RADIOTAP: the radiotap 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

struct ieee80211_conf - configuration of the device

struct ieee80211_conf {
int __deprecated beacon_int;
u32 flags;
int power_level;
int dynamic_ps_timeout;
int max_sleep_period;
u16 listen_interval;
bool __deprecated radio_enabled;
u8 long_frame_max_tx_count;
u8 short_frame_max_tx_count;
struct ieee80211_channel * channel;
enum nl80211_channel_type channel_type;
};

Members

beacon_int: DEPRECATED, DO NOT USE
flags: configuration flags defined above
power_level: requested transmit power (in dBm)
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.
max_sleep_period: the maximum number of beacon intervals to sleep for before checking the beacon for a TIM bit (managed mode only); this value will be only achievable between DTIM frames, the hardware needs to check for the multicast traffic bit in DTIM beacons. This variable is valid only when the CONF_PS flag is set.
listen_interval: listen interval in units of beacon interval
radio_enabled: when zero, driver is required to switch off the radio.
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
channel: the channel to tune to
channel_type: the channel (HT) type

Description

This struct indicates how the driver shall configure the hardware.

struct ieee80211_vif - per-interface data

struct ieee80211_vif {
enum nl80211_iftype type;
struct ieee80211_bss_conf bss_conf;
u8 drv_priv[0] __attribute__((__aligned__(sizeof(void *))));
};

Members

type: type of this virtual interface
bss_conf: BSS configuration for this interface, either our own or the BSS we're associated to
drv_priv[0] __attribute__((__aligned__(sizeof(void *)))): data area for driver use, will always be aligned to sizeof(void *).

Description

Data in this structure is continually present for driver use during the life of a virtual interface.

struct ieee80211_if_init_conf - initial configuration of an interface

struct ieee80211_if_init_conf {
enum nl80211_iftype type;
struct ieee80211_vif * vif;
void * mac_addr;
};

Members

type: one of enum nl80211_iftype constants. Determines the type of added/removed interface.
vif: pointer to a driver-use per-interface structure. The pointer itself is also used for various functions including ieee80211_beacon_get and ieee80211_get_buffered_bc.
mac_addr: pointer to MAC address of the interface. This pointer is valid until the interface is removed (i.e. it cannot be used after remove_interface callback was called for this interface).

Description

This structure is used in add_interface and remove_interface callbacks of struct ieee80211_hw.
When you allow multiple interfaces to be added to your PHY, take care that the hardware can actually handle multiple MAC addresses. However, also take care that when there's no interface left with mac_addr != NULL you remove the MAC address from the device to avoid acknowledging packets in pure monitor mode.

enum ieee80211_key_alg

enum ieee80211_key_alg {
ALG_WEP,
ALG_TKIP,
ALG_CCMP,
ALG_AES_CMAC
};

Constants

ALG_WEP: WEP40 or WEP104
ALG_TKIP: TKIP
ALG_CCMP: CCMP (AES)
ALG_AES_CMAC: AES-128-CMAC

enum ieee80211_key_flags

enum ieee80211_key_flags {
IEEE80211_KEY_FLAG_WMM_STA,
IEEE80211_KEY_FLAG_GENERATE_IV,
IEEE80211_KEY_FLAG_GENERATE_MMIC,
IEEE80211_KEY_FLAG_PAIRWISE,
IEEE80211_KEY_FLAG_SW_MGMT
};

Constants

IEEE80211_KEY_FLAG_WMM_STA: Set by mac80211, this flag indicates that the STA this key will be used with could be using QoS.
IEEE80211_KEY_FLAG_GENERATE_IV: This flag should be set by the driver to indicate that it requires IV generation for this particular key.
IEEE80211_KEY_FLAG_GENERATE_MMIC: This flag should be set by the driver for a TKIP key if it requires Michael MIC generation in software.
IEEE80211_KEY_FLAG_PAIRWISE: Set by mac80211, this flag indicates that the key is pairwise rather then a shared key.
IEEE80211_KEY_FLAG_SW_MGMT: This flag should be set by the driver for a CCMP key if it requires CCMP encryption of management frames (MFP) to be done in software.

Description

These flags are used for communication about keys between the driver and mac80211, with the flags parameter of struct ieee80211_key_conf.

struct ieee80211_key_conf - key information

struct ieee80211_key_conf {
enum ieee80211_key_alg alg;
u8 icv_len;
u8 iv_len;
u8 hw_key_idx;
u8 flags;
s8 keyidx;
u8 keylen;
u8 key[0];
};

Members

alg: The key algorithm.
icv_len: The ICV length for this key type
iv_len: The IV length for this key type
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.
flags: key flags, see enum ieee80211_key_flags.
keyidx: the key index (0-3)
keylen: key material length
key[0]: key material. For ALG_TKIP the key is encoded as a 256-bit (32 byte)

Description

This key information is given by mac80211 to the driver by the set_key callback in struct ieee80211_ops.

data block

- Temporal Encryption Key (128 bits) - Temporal Authenticator Tx MIC Key (64 bits) - Temporal Authenticator Rx MIC Key (64 bits)

enum set_key_cmd

enum set_key_cmd {
SET_KEY,
DISABLE_KEY
};

Constants

SET_KEY: a key is set
DISABLE_KEY: a key must be disabled

Description

Used with the set_key callback in struct ieee80211_ops, this indicates whether a key is being removed or added.

struct ieee80211_sta - station table entry

struct ieee80211_sta {
u32 supp_rates[IEEE80211_NUM_BANDS];
u8 addr[ETH_ALEN];
u16 aid;
struct ieee80211_sta_ht_cap ht_cap;
u8 drv_priv[0] __attribute__((__aligned__(sizeof(void *))));
};

Members

supp_rates[IEEE80211_NUM_BANDS]: Bitmap of supported rates (per band)
addr[ETH_ALEN]: MAC address
aid: AID we assigned to the station if we're an AP
ht_cap: HT capabilities of this STA; restricted to our own TX capabilities
drv_priv[0] __attribute__((__aligned__(sizeof(void *)))): data area for driver use, will always be aligned to sizeof(void *), size is determined in hw information.

Description

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_notify callback that removed it.

enum sta_notify_cmd

enum sta_notify_cmd {
STA_NOTIFY_ADD,
STA_NOTIFY_REMOVE,
STA_NOTIFY_SLEEP,
STA_NOTIFY_AWAKE
};

Constants

STA_NOTIFY_ADD: a station was added to the station table
STA_NOTIFY_REMOVE: a station being removed from the station table
STA_NOTIFY_SLEEP: a station is now sleeping
STA_NOTIFY_AWAKE: a sleeping station woke up

Description

Used with the sta_notify callback in struct ieee80211_ops, this indicates addition and removal of a station to station table, or if a associated station made a power state transition.

enum ieee80211_tkip_key_type

enum ieee80211_tkip_key_type {
IEEE80211_TKIP_P1_KEY,
IEEE80211_TKIP_P2_KEY
};

Constants

IEEE80211_TKIP_P1_KEY: the driver needs a phase 1 key
IEEE80211_TKIP_P2_KEY: the driver needs a phase 2 key

Description

Used by drivers which need to get a tkip key for skb. Some drivers need a phase 1 key, others need a phase 2 key. A single function allows the driver to get the key, this enum indicates what type of key is required.

enum ieee80211_hw_flags

enum ieee80211_hw_flags {
IEEE80211_HW_RX_INCLUDES_FCS,
IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING,
IEEE80211_HW_2GHZ_SHORT_SLOT_INCAPABLE,
IEEE80211_HW_2GHZ_SHORT_PREAMBLE_INCAPABLE,
IEEE80211_HW_SIGNAL_UNSPEC,
IEEE80211_HW_SIGNAL_DBM,
IEEE80211_HW_NOISE_DBM,
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_BEACON_FILTER
};

Constants

IEEE80211_HW_RX_INCLUDES_FCS: Indicates that received frames passed to the stack include the FCS at the end.
IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING: Some wireless LAN chipsets buffer broadcast/multicast frames for power saving stations in the hardware/firmware and others rely on the host system for such buffering. This option is used to configure the IEEE 802.11 upper layer to buffer broadcast and multicast frames when there are power saving stations so that the driver can fetch them with ieee80211_get_buffered_bc.
IEEE80211_HW_2GHZ_SHORT_SLOT_INCAPABLE: Hardware is not capable of short slot operation on the 2.4 GHz band.
IEEE80211_HW_2GHZ_SHORT_PREAMBLE_INCAPABLE: Hardware is not capable of receiving frames with short preamble on the 2.4 GHz band.
IEEE80211_HW_SIGNAL_UNSPEC: Hardware can provide signal values but we don't know its units. We expect values between 0 and max_signal. If possible please provide dB or dBm instead.
IEEE80211_HW_SIGNAL_DBM: Hardware gives signal values in dBm, decibel difference from one milliwatt. This is the preferred method since it is standardized between different devices. max_signal does not need to be set.
IEEE80211_HW_NOISE_DBM: Hardware can provide noise (radio interference) values in units dBm, decibel difference from one milliwatt.
IEEE80211_HW_SPECTRUM_MGMT: Hardware supports spectrum management defined in 802.11h Measurement, Channel Switch, Quieting, TPC
IEEE80211_HW_AMPDU_AGGREGATION: Hardware supports 11n A-MPDU aggregation.
IEEE80211_HW_SUPPORTS_PS: Hardware has power save support (i.e. can go to sleep).
IEEE80211_HW_PS_NULLFUNC_STACK: Hardware requires nullfunc frame handling in stack, implies stack support for dynamic PS.
IEEE80211_HW_SUPPORTS_DYNAMIC_PS: Hardware has support for dynamic PS.
IEEE80211_HW_MFP_CAPABLE: Hardware supports management frame protection (MFP, IEEE 802.11w).
IEEE80211_HW_BEACON_FILTER: Hardware supports dropping of irrelevant beacon frames to avoid waking up cpu.

Description

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.

struct ieee80211_hw - hardware information and state

struct ieee80211_hw {
struct ieee80211_conf conf;
struct wiphy * wiphy;
struct workqueue_struct * workqueue;
const char * rate_control_algorithm;
void * priv;
u32 flags;
unsigned int extra_tx_headroom;
int channel_change_time;
int vif_data_size;
int sta_data_size;
u16 queues;
u16 max_listen_interval;
s8 max_signal;
u8 max_rates;
u8 max_rate_tries;
};

Members

conf: struct ieee80211_conf, device configuration, don't use.
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.
workqueue: single threaded workqueue available for driver use, allocated by mac80211 on registration and flushed when an interface is removed.
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.
priv: pointer to private area that was allocated for driver use along with this structure.
flags: hardware flags, see enum ieee80211_hw_flags.
extra_tx_headroom: headroom to reserve in each transmit skb for use by the driver (e.g. for transmit headers.)
channel_change_time: time (in microseconds) it takes to change channels.
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.
queues: number of available hardware transmit queues for data packets. WMM/QoS requires at least four, these queues need to have configurable access parameters.
max_listen_interval: max listen interval in units of beacon interval that HW supports
max_signal: Maximum value for signal (rssi) in RX information, used only when IEEE80211_HW_SIGNAL_UNSPEC or IEEE80211_HW_SIGNAL_DB
max_rates: maximum number of alternate rate retry stages
max_rate_tries: maximum number of tries for each stage

Description

This structure contains the configuration and hardware information for an 802.11 PHY.

NOTICE

All work performed on this workqueue must not acquire the RTNL lock.

wiphy_to_ieee80211_hw - return a mac80211 driver hw struct from a wiphy

struct ieee80211_hw * wiphy_to_ieee80211_hw (struct wiphy * wiphy)

Arguments

wiphy: the struct wiphy which we want to query

Description

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.

SET_IEEE80211_DEV - set device for 802.11 hardware

void SET_IEEE80211_DEV (struct ieee80211_hw * hw, struct device * dev)

Arguments

hw: the struct ieee80211_hw to set the device for
dev: the struct device of this 802.11 device

SET_IEEE80211_PERM_ADDR - set the permanent MAC address for 802.11 hardware

void SET_IEEE80211_PERM_ADDR (struct ieee80211_hw * hw, u8 * addr)

Arguments

hw: the struct ieee80211_hw to set the MAC address for
addr: the address to set

Hardware crypto acceleration

mac80211 is capable of taking advantage of many hardware acceleration designs for encryption and decryption operations.

The set_key callback in the struct ieee80211_ops for a given device is called to enable hardware acceleration of encryption and decryption. The callback takes a sta parameter that will be NULL for default keys or keys used for transmission only, or point to the station information for the peer for individual keys. Multiple transmission keys with the same key index may be used when VLANs are configured for an access point.

When transmitting, the TX control data will use the hw_key_idx selected by the driver by modifying the struct ieee80211_key_conf pointed to by the key parameter to the set_key function.

The set_key call for the SET_KEY command should return 0 if the key is now in use, -EOPNOTSUPP or -ENOSPC if it couldn't be added; if you return 0 then hw_key_idx must be assigned to the hardware key index, you are free to use the full u8 range.

When the cmd is DISABLE_KEY then it must succeed.

Note that it is permissible to not decrypt a frame even if a key for it has been uploaded to hardware, the stack will not make any decision based on whether a key has been uploaded or not but rather based on the receive flags.

The struct ieee80211_key_conf structure pointed to by the key parameter is guaranteed to be valid until another call to set_key removes it, but it can only be used as a cookie to differentiate keys.

In TKIP some HW need to be provided a phase 1 key, for RX decryption acceleration (i.e. iwlwifi). Those drivers should provide update_tkip_key handler. The update_tkip_key call updates the driver with the new phase 1 key. This happens everytime the iv16 wraps around (every 65536 packets). The set_key call will happen only once for each key (unless the AP did rekeying), it will not include a valid phase 1 key. The valid phase 1 key is provided by update_tkip_key only. The trigger that makes mac80211 call this handler is software decryption with wrap around of iv16.

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 depending on the association status, and the driver must take care of sending nullfunc frames when necessary, i.e. when entering and leaving powersave mode. The driver 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. This mode supports dynamic PS by simply enabling/disabling PS.

Additionally, such hardware may set the IEEE80211_HW_SUPPORTS_DYNAMIC_PS flag to indicate that it can support dynamic PS mode itself (see below).

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.

Dynamic powersave mode is an extension to normal powersave mode 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. This can either be supported by hardware, in which case the driver needs to look at the dynamic_ps_timeout hardware configuration value, or by the stack if all nullfunc handling is in the stack.

Beacon filter support

Some hardware have beacon filter support to reduce host cpu wakeups which will reduce system power consumption. It usuallly works so that the firmware creates a checksum of the beacon but omits all constantly changing elements (TSF, TIM etc). Whenever the checksum changes the beacon is forwarded to the host, otherwise it will be just dropped. That way the host will only receive beacons where some relevant information (for example ERP protection or WMM settings) have changed.

Beacon filter support is advertised with the IEEE80211_HW_BEACON_FILTER hardware capability. The driver needs to enable beacon filter support whenever power save is enabled, that is IEEE80211_CONF_PS is set. When power save is enabled, the stack will not check for beacon loss and the driver needs to notify about loss of beacons with ieee80211_beacon_loss.

The time (or number of beacons missed) until the firmware notifies the driver of a beacon loss event (which in turn causes the driver to call ieee80211_beacon_loss) should be configurable and will be controlled by mac80211 and the roaming algorithm in the future.

Since there may be constantly changing information elements that nothing in the software stack cares about, we will, in the future, have mac80211 tell the driver which information elements are interesting in the sense that we want to see changes in them. This will include - a list of information element IDs - a list of OUIs for the vendor information element

Ideally, the hardware would filter out any beacons without changes in the requested elements, but if it cannot support that it may, at the expense of some efficiency, filter out only a subset. For example, if the device doesn't support checking for OUIs it should pass up all changes in all vendor information elements.

Note that change, for the sake of simplification, also includes information elements appearing or disappearing from the beacon.

Some hardware supports an "ignore list" instead, just make sure nothing that was requested is on the ignore list, and include commonly changing information element IDs in the ignore list, for example 11 (BSS load) and the various vendor-assigned IEs with unknown contents (128, 129, 133-136, 149, 150, 155, 156, 173, 176, 178, 179, 219); for forward compatibility it could also include some currently unused IDs.

In addition to these capabilities, hardware should support notifying the host of changes in the beacon RSSI. This is relevant to implement roaming when no traffic is flowing (when traffic is flowing we see the RSSI of the received data packets). This can consist in notifying the host when the RSSI changes significantly or when it drops below or rises above configurable thresholds. In the future these thresholds will also be configured by mac80211 (which gets them from userspace) to implement them as the roaming algorithm requires.

If the hardware cannot implement this, the driver should ask it to periodically pass beacon frames to the host so that software can do the signal strength threshold checking.

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.

The configure_filter callback is invoked with the parameters mc_count and mc_list for the combined multicast address list of all virtual interfaces, changed_flags telling which flags were changed and total_flags with the new flag states.

If your device has no multicast address filters your driver will need to check both the FIF_ALLMULTI flag and the mc_count parameter to see whether multicast frames should be accepted or dropped.

All unsupported flags in total_flags must be cleared. Hardware does not support a flag if it is incapable of _passing_ the frame to the stack. Otherwise the driver must ignore the flag, but not clear it. You must _only_ clear the flag (announce no support for the flag to mac80211) if you are not able to pass the packet type to the stack (so the hardware always filters it). So for example, you should clear FIF_CONTROL, if your hardware always filters control frames. If your hardware always passes control frames to the kernel and is incapable of filtering them, you do _not_ clear the FIF_CONTROL flag. This rule applies to all other FIF flags as well.

enum ieee80211_filter_flags

enum ieee80211_filter_flags {
FIF_PROMISC_IN_BSS,
FIF_ALLMULTI,
FIF_FCSFAIL,
FIF_PLCPFAIL,
FIF_BCN_PRBRESP_PROMISC,
FIF_CONTROL,
FIF_OTHER_BSS
};

Constants

FIF_PROMISC_IN_BSS: promiscuous mode within your BSS, think of the BSS as your network segment and then this corresponds to the regular ethernet device promiscuous mode.
FIF_ALLMULTI: pass all multicast frames, this is used if requested by the user or if the hardware is not capable of filtering by multicast address.
FIF_FCSFAIL: pass frames with failed FCS (but you need to set the RX_FLAG_FAILED_FCS_CRC for them)
FIF_PLCPFAIL: pass frames with failed PLCP CRC (but you need to set the RX_FLAG_FAILED_PLCP_CRC for them
FIF_BCN_PRBRESP_PROMISC: This flag is set during scanning to indicate to the hardware that it should not filter beacons or probe responses by BSSID. Filtering them can greatly reduce the amount of processing mac80211 needs to do and the amount of CPU wakeups, so you should honour this flag if possible.
FIF_CONTROL: pass control frames, if PROMISC_IN_BSS is not set then only those addressed to this station
FIF_OTHER_BSS: pass frames destined to other BSSes

Frame filtering

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.

enum ieee80211_ampdu_mlme_action

enum ieee80211_ampdu_mlme_action {
IEEE80211_AMPDU_RX_START,
IEEE80211_AMPDU_RX_STOP,
IEEE80211_AMPDU_TX_START,
IEEE80211_AMPDU_TX_STOP,
IEEE80211_AMPDU_TX_OPERATIONAL
};

Constants

IEEE80211_AMPDU_RX_START: start Rx aggregation
IEEE80211_AMPDU_RX_STOP: stop Rx aggregation
IEEE80211_AMPDU_TX_START: start Tx aggregation
IEEE80211_AMPDU_TX_STOP: stop Tx aggregation
IEEE80211_AMPDU_TX_OPERATIONAL: TX aggregation has become operational

Description

These flags are used with the ampdu_action callback in struct ieee80211_ops to indicate which action is needed.

struct ieee80211_ops - callbacks from mac80211 to the driver

struct ieee80211_ops {
int (*tx) (struct ieee80211_hw *hw, struct sk_buff *skb);
int (*start) (struct ieee80211_hw *hw);
void (*stop) (struct ieee80211_hw *hw);
int (*add_interface) (struct ieee80211_hw *hw,struct ieee80211_if_init_conf *conf);
void (*remove_interface) (struct ieee80211_hw *hw,struct ieee80211_if_init_conf *conf);
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);
void (*configure_filter) (struct ieee80211_hw *hw,unsigned int changed_flags,unsigned int *total_flags,int mc_count, struct dev_addr_list *mc_list);
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_key_conf *conf, const u8 *address,u32 iv32, u16 *phase1key);
int (*hw_scan) (struct ieee80211_hw *hw,struct cfg80211_scan_request *req);
void (*sw_scan_start) (struct ieee80211_hw *hw);
void (*sw_scan_complete) (struct ieee80211_hw *hw);
int (*get_stats) (struct ieee80211_hw *hw,struct ieee80211_low_level_stats *stats);
void (*get_tkip_seq) (struct ieee80211_hw *hw, u8 hw_key_idx,u32 *iv32, u16 *iv16);
int (*set_rts_threshold) (struct ieee80211_hw *hw, u32 value);
void (*sta_notify) (struct ieee80211_hw *hw, struct ieee80211_vif *vif,enum sta_notify_cmd, struct ieee80211_sta *sta);
int (*conf_tx) (struct ieee80211_hw *hw, u16 queue,const struct ieee80211_tx_queue_params *params);
int (*get_tx_stats) (struct ieee80211_hw *hw,struct ieee80211_tx_queue_stats *stats);
u64 (*get_tsf) (struct ieee80211_hw *hw);
void (*set_tsf) (struct ieee80211_hw *hw, u64 tsf);
void (*reset_tsf) (struct ieee80211_hw *hw);
int (*tx_last_beacon) (struct ieee80211_hw *hw);
int (*ampdu_action) (struct ieee80211_hw *hw,enum ieee80211_ampdu_mlme_action action,struct ieee80211_sta *sta, u16 tid, u16 *ssn);
void (*rfkill_poll) (struct ieee80211_hw *hw);
};

Members

tx: Handler that 802.11 module calls for each transmitted frame. skb contains the buffer starting from the IEEE 802.11 header. The low-level driver should send the frame out based on configuration in the TX control data. This handler should, preferably, never fail and stop queues appropriately, more importantly, however, it must never fail for A-MPDU-queues. This function should return NETDEV_TX_OK except in very limited cases. Must be implemented and atomic.
start: Called before the first netdevice attached to the hardware is enabled. This should turn on the hardware and must turn on frame reception (for possibly enabled monitor interfaces.) Returns negative error codes, these may be seen in userspace, or zero. When the device is started it should not have a MAC address to avoid acknowledging frames before a non-monitor device is added. Must be implemented.
stop: Called after last netdevice attached to the hardware is disabled. This should turn off the hardware (at least it must turn off frame reception.) May be called right after add_interface if that rejects an interface. Must be implemented.
add_interface: Called when a netdevice attached to the hardware is enabled. Because it is not called for monitor mode devices, 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.
remove_interface: Notifies a driver that an interface is going down. The stop callback is called after this if it is the last interface and no monitor interfaces are present. When all interfaces are removed, the MAC address in the hardware must be cleared so the device no longer acknowledges packets, the mac_addr member of the conf structure is, however, set to the MAC address of the device going away. Hence, this callback must be implemented.
config: Handler for configuration requests. IEEE 802.11 code calls this function to change hardware configuration, e.g., channel. This function should never fail but returns a negative error code if it does.
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.
configure_filter: Configure the device's RX filter. See the section "Frame filtering" for more information. This callback must be implemented and atomic.
set_tim: Set TIM bit. 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 can sleep, and 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.
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.
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.
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.
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.
get_stats: Return low-level statistics. Returns zero if statistics are available.
get_tkip_seq: If your device implements TKIP encryption in hardware this callback should be provided to read the TKIP transmit IVs (both IV32 and IV16) for the given key from hardware.
set_rts_threshold: Configuration of RTS threshold (if device needs it)
sta_notify: Notifies low level driver about addition, removal or power state transition of an associated station, AP, IBSS/WDS/mesh peer etc. Must be atomic.
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.
get_tx_stats: Get statistics of the current TX queue status. This is used to get number of currently queued packets (queue length), maximum queue size (limit), and total number of packets sent using each TX queue (count). The 'stats' pointer points to an array that has hw->queues items.
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.
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.
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.
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.
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. Starting sequence number (ssn) is the first frame we expect to perform the action on. Notice that TX/RX_STOP can pass NULL for this parameter. Returns a negative error code on failure.
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.

Description

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.

ieee80211_alloc_hw - Allocate a new hardware device

struct ieee80211_hw * ieee80211_alloc_hw (size_t priv_data_len, const struct ieee80211_ops * ops)

Arguments

priv_data_len: length of private data
ops: callbacks for this device

Description

This must be called once for each hardware device. The returned pointer must be used to refer to this device when calling other functions. mac80211 allocates a private data area for the driver pointed to by priv in struct ieee80211_hw, the size of this area is given as priv_data_len.

ieee80211_register_hw - Register hardware device

int ieee80211_register_hw (struct ieee80211_hw * hw)

Arguments

hw: the device to register as returned by ieee80211_alloc_hw

Description

You must call this function before any other functions in mac80211. Note that before a hardware can be registered, you need to fill the contained wiphy's information.

ieee80211_get_tx_led_name - get name of TX LED

char * ieee80211_get_tx_led_name (struct ieee80211_hw * hw)

Arguments

hw: the hardware to get the LED trigger name for

Description

mac80211 creates a transmit LED trigger for each wireless hardware that can be used to drive LEDs if your driver registers a LED device. This function returns the name (or NULL if not configured for LEDs) of the trigger so you can automatically link the LED device.

ieee80211_get_rx_led_name - get name of RX LED

char * ieee80211_get_rx_led_name (struct ieee80211_hw * hw)

Arguments

hw: the hardware to get the LED trigger name for

Description

mac80211 creates a receive LED trigger for each wireless hardware that can be used to drive LEDs if your driver registers a LED device. This function returns the name (or NULL if not configured for LEDs) of the trigger so you can automatically link the LED device.

ieee80211_get_assoc_led_name - get name of association LED

char * ieee80211_get_assoc_led_name (struct ieee80211_hw * hw)

Arguments

hw: the hardware to get the LED trigger name for

Description

mac80211 creates a association LED trigger for each wireless hardware that can be used to drive LEDs if your driver registers a LED device. This function returns the name (or NULL if not configured for LEDs) of the trigger so you can automatically link the LED device.

ieee80211_get_radio_led_name - get name of radio LED

char * ieee80211_get_radio_led_name (struct ieee80211_hw * hw)

Arguments

hw: the hardware to get the LED trigger name for

Description

mac80211 creates a radio change LED trigger for each wireless hardware that can be used to drive LEDs if your driver registers a LED device. This function returns the name (or NULL if not configured for LEDs) of the trigger so you can automatically link the LED device.

ieee80211_unregister_hw - Unregister a hardware device

void ieee80211_unregister_hw (struct ieee80211_hw * hw)

Arguments

hw: the hardware to unregister

Description

This function instructs mac80211 to free allocated resources and unregister netdevices from the networking subsystem.

ieee80211_free_hw - free hardware descriptor

void ieee80211_free_hw (struct ieee80211_hw * hw)

Arguments

hw: the hardware to free

Description

This function frees everything that was allocated, including the private data for the driver. You must call ieee80211_unregister_hw before calling this function.

ieee80211_restart_hw - restart hardware completely

void ieee80211_restart_hw (struct ieee80211_hw * hw)

Arguments

hw: the hardware to restart

Description

Call this function when the hardware was restarted for some reason (hardware error, ...) and the driver is unable to restore its state by itself. mac80211 assumes that at this point the driver/hardware is completely uninitialised and stopped, it starts the process by calling the ->start operation. The driver will need to reset all internal state that it has prior to calling this function.

ieee80211_rx - receive frame

void ieee80211_rx (struct ieee80211_hw * hw, struct sk_buff * skb)

Arguments

hw: the hardware this frame came in on
skb: the buffer to receive, owned by mac80211 after this call

Description

Use this function to hand received frames to mac80211. The receive buffer in skb must start with an IEEE 802.11 header or a radiotap header if RX_FLAG_RADIOTAP is set in the status flags.
This function may not be called in IRQ context. Calls to this function for a single hardware must be synchronized against each other. Calls to this function and ieee80211_rx_irqsafe may not be mixed for a single hardware.

ieee80211_rx_irqsafe - receive frame

void ieee80211_rx_irqsafe (struct ieee80211_hw * hw, struct sk_buff * skb)

Arguments

hw: the hardware this frame came in on
skb: the buffer to receive, owned by mac80211 after this call

Description

Like ieee80211_rx but can be called in IRQ context (internally defers to a tasklet.)
Calls to this function and ieee80211_rx may not be mixed for a single hardware.

ieee80211_tx_status - transmit status callback

void ieee80211_tx_status (struct ieee80211_hw * hw, struct sk_buff * skb)

Arguments

hw: the hardware the frame was transmitted by
skb: the frame that was transmitted, owned by mac80211 after this call

Description

Call this function for all transmitted frames after they have been transmitted. It is permissible to not call this function for multicast frames but this can affect statistics.
This function may not be called in IRQ context. Calls to this function for a single hardware must be synchronized against each other. Calls to this function and ieee80211_tx_status_irqsafe may not be mixed for a single hardware.

ieee80211_tx_status_irqsafe - IRQ-safe transmit status callback

void ieee80211_tx_status_irqsafe (struct ieee80211_hw * hw, struct sk_buff * skb)

Arguments

hw: the hardware the frame was transmitted by
skb: the frame that was transmitted, owned by mac80211 after this call

Description

Like ieee80211_tx_status but can be called in IRQ context (internally defers to a tasklet.)
Calls to this function and ieee80211_tx_status may not be mixed for a single hardware.

ieee80211_beacon_get - beacon generation function

struct sk_buff * ieee80211_beacon_get (struct ieee80211_hw * hw, struct ieee80211_vif * vif)

Arguments

hw: pointer obtained from ieee80211_alloc_hw.
vif: struct ieee80211_vif pointer from struct ieee80211_if_init_conf.

Description

If the beacon frames are generated by the host system (i.e., not in hardware/firmware), the low-level driver uses this function to receive the next beacon frame from the 802.11 code. The low-level is responsible for calling this function before beacon data is needed (e.g., based on hardware interrupt). Returned skb is used only once and low-level driver is responsible for freeing it.

ieee80211_rts_get - RTS frame generation function

void ieee80211_rts_get (struct ieee80211_hw * hw, struct ieee80211_vif * vif, const void * frame, size_t frame_len, const struct ieee80211_tx_info * frame_txctl, struct ieee80211_rts * rts)

Arguments

hw: pointer obtained from ieee80211_alloc_hw.
vif: struct ieee80211_vif pointer from struct ieee80211_if_init_conf.
frame: pointer to the frame that is going to be protected by the RTS.
frame_len: the frame length (in octets).
frame_txctl: struct ieee80211_tx_info of the frame.
rts: The buffer where to store the RTS frame.

Description

If the RTS frames are generated by the host system (i.e., not in hardware/firmware), the low-level driver uses this function to receive the next RTS frame from the 802.11 code. The low-level is responsible for calling this function before and RTS frame is needed.

ieee80211_rts_duration - Get the duration field for an RTS frame

__le16 ieee80211_rts_duration (struct ieee80211_hw * hw, struct ieee80211_vif * vif, size_t frame_len, const struct ieee80211_tx_info * frame_txctl)

Arguments

hw: pointer obtained from ieee80211_alloc_hw.
vif: struct ieee80211_vif pointer from struct ieee80211_if_init_conf.
frame_len: the length of the frame that is going to be protected by the RTS.
frame_txctl: struct ieee80211_tx_info of the frame.

Description

If the RTS is generated in firmware, but the host system must provide the duration field, the low-level driver uses this function to receive the duration field value in little-endian byteorder.

ieee80211_ctstoself_get - CTS-to-self frame generation function

void ieee80211_ctstoself_get (struct ieee80211_hw * hw, struct ieee80211_vif * vif, const void * frame, size_t frame_len, const struct ieee80211_tx_info * frame_txctl, struct ieee80211_cts * cts)

Arguments

hw: pointer obtained from ieee80211_alloc_hw.
vif: struct ieee80211_vif pointer from struct ieee80211_if_init_conf.
frame: pointer to the frame that is going to be protected by the CTS-to-self.
frame_len: the frame length (in octets).
frame_txctl: struct ieee80211_tx_info of the frame.
cts: The buffer where to store the CTS-to-self frame.

Description

If the CTS-to-self frames are generated by the host system (i.e., not in hardware/firmware), the low-level driver uses this function to receive the next CTS-to-self frame from the 802.11 code. The low-level is responsible for calling this function before and CTS-to-self frame is needed.

ieee80211_ctstoself_duration - Get the duration field for a CTS-to-self frame

__le16 ieee80211_ctstoself_duration (struct ieee80211_hw * hw, struct ieee80211_vif * vif, size_t frame_len, const struct ieee80211_tx_info * frame_txctl)

Arguments

hw: pointer obtained from ieee80211_alloc_hw.
vif: struct ieee80211_vif pointer from struct ieee80211_if_init_conf.
frame_len: the length of the frame that is going to be protected by the CTS-to-self.
frame_txctl: struct ieee80211_tx_info of the frame.

Description

If the CTS-to-self is generated in firmware, but the host system must provide the duration field, the low-level driver uses this function to receive the duration field value in little-endian byteorder.

ieee80211_generic_frame_duration - Calculate the duration field for a frame

__le16 ieee80211_generic_frame_duration (struct ieee80211_hw * hw, struct ieee80211_vif * vif, size_t frame_len, struct ieee80211_rate * rate)

Arguments

hw: pointer obtained from ieee80211_alloc_hw.
vif: struct ieee80211_vif pointer from struct ieee80211_if_init_conf.
frame_len: the length of the frame.
rate: the rate at which the frame is going to be transmitted.

Description

Calculate the duration field of some generic frame, given its length and transmission rate (in 100kbps).

ieee80211_get_buffered_bc - accessing buffered broadcast and multicast frames

struct sk_buff * ieee80211_get_buffered_bc (struct ieee80211_hw * hw, struct ieee80211_vif * vif)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw.
vif: struct ieee80211_vif pointer from struct ieee80211_if_init_conf.

Description

Function for accessing buffered broadcast and multicast frames. If hardware/firmware does not implement buffering of broadcast/multicast frames when power saving is used, 802.11 code buffers them in the host memory. The low-level driver uses this function to fetch next buffered frame. In most cases, this is used when generating beacon frame. This function returns a pointer to the next buffered skb or NULL if no more buffered frames are available.

Note

buffered frames are returned only after DTIM beacon frame was generated with ieee80211_beacon_get and the low-level driver must thus call ieee80211_beacon_get first. ieee80211_get_buffered_bc returns NULL if the previous generated beacon was not DTIM, so the low-level driver does not need to check for DTIM beacons separately and should be able to use common code for all beacons.

ieee80211_get_tkip_key - get a TKIP rc4 for skb

void ieee80211_get_tkip_key (struct ieee80211_key_conf * keyconf, struct sk_buff * skb, enum ieee80211_tkip_key_type type, u8 * key)

Arguments

keyconf: the parameter passed with the set key
skb: the skb for which the key is needed
type: TBD
key: a buffer to which the key will be written

Description

This function computes a TKIP rc4 key for an skb. It computes a phase 1 key if needed (iv16 wraps around). This function is to be used by drivers which can do HW encryption but need to compute to phase 1/2 key in SW.

ieee80211_wake_queue - wake specific queue

void ieee80211_wake_queue (struct ieee80211_hw * hw, int queue)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw.
queue: queue number (counted from zero).

Description

Drivers should use this function instead of netif_wake_queue.

ieee80211_stop_queue - stop specific queue

void ieee80211_stop_queue (struct ieee80211_hw * hw, int queue)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw.
queue: queue number (counted from zero).

Description

Drivers should use this function instead of netif_stop_queue.

ieee80211_queue_stopped - test status of the queue

int ieee80211_queue_stopped (struct ieee80211_hw * hw, int queue)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw.
queue: queue number (counted from zero).

Description

Drivers should use this function instead of netif_stop_queue.

ieee80211_stop_queues - stop all queues

void ieee80211_stop_queues (struct ieee80211_hw * hw)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw.

Description

Drivers should use this function instead of netif_stop_queue.

ieee80211_wake_queues - wake all queues

void ieee80211_wake_queues (struct ieee80211_hw * hw)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw.

Description

Drivers should use this function instead of netif_wake_queue.

ieee80211_scan_completed - completed hardware scan

void ieee80211_scan_completed (struct ieee80211_hw * hw, bool aborted)

Arguments

hw: the hardware that finished the scan
aborted: set to true if scan was aborted

Description

When hardware scan offload is used (i.e. the hw_scan callback is assigned) this function needs to be called by the driver to notify mac80211 that the scan finished.

ieee80211_iterate_active_interfaces - iterate active interfaces

void ieee80211_iterate_active_interfaces (struct ieee80211_hw * hw, void (*iterator) (void *data, u8 *mac, struct ieee80211_vif *vif), void * data)

Arguments

hw: the hardware struct of which the interfaces should be iterated over
iterator: the iterator function to call
data: first argument of the iterator function

Description

This function iterates over the interfaces associated with a given hardware that are currently active and calls the callback for them. This function allows the iterator function to sleep, when the iterator function is atomic ieee80211_iterate_active_interfaces_atomic can be used.

ieee80211_iterate_active_interfaces_atomic - iterate active interfaces

void ieee80211_iterate_active_interfaces_atomic (struct ieee80211_hw * hw, void (*iterator) (void *data, u8 *mac, struct ieee80211_vif *vif), void * data)

Arguments

hw: the hardware struct of which the interfaces should be iterated over
iterator: the iterator function to call, cannot sleep
data: first argument of the iterator function

Description

This function iterates over the interfaces associated with a given hardware that are currently active and calls the callback for them. This function requires the iterator callback function to be atomic, if that is not desired, use ieee80211_iterate_active_interfaces instead.

ieee80211_start_tx_ba_session - Start a tx Block Ack session.

int ieee80211_start_tx_ba_session (struct ieee80211_hw * hw, u8 * ra, u16 tid)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw.
ra: receiver address of the BA session recipient
tid: the TID to BA on.

Return

success if addBA request was sent, failure otherwise
Although mac80211/low level driver/user space application can estimate the need to start aggregation on a certain RA/TID, the session level will be managed by the mac80211.

ieee80211_start_tx_ba_cb - low level driver ready to aggregate.

void ieee80211_start_tx_ba_cb (struct ieee80211_hw * hw, u8 * ra, u16 tid)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw.
ra: receiver address of the BA session recipient.
tid: the TID to BA on.

Description

This function must be called by low level driver once it has finished with preparations for the BA session.

ieee80211_start_tx_ba_cb_irqsafe - low level driver ready to aggregate.

void ieee80211_start_tx_ba_cb_irqsafe (struct ieee80211_hw * hw, const u8 * ra, u16 tid)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw.
ra: receiver address of the BA session recipient.
tid: the TID to BA on.

Description

This function must be called by low level driver once it has finished with preparations for the BA session. This version of the function is IRQ-safe.

ieee80211_stop_tx_ba_session - Stop a Block Ack session.

int ieee80211_stop_tx_ba_session (struct ieee80211_hw * hw, u8 * ra, u16 tid, enum ieee80211_back_parties initiator)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw.
ra: receiver address of the BA session recipient
tid: the TID to stop BA.
initiator: if indicates initiator DELBA frame will be sent.

Return

error if no sta with matching da found, success otherwise
Although mac80211/low level driver/user space application can estimate the need to stop aggregation on a certain RA/TID, the session level will be managed by the mac80211.

ieee80211_stop_tx_ba_cb - low level driver ready to stop aggregate.

void ieee80211_stop_tx_ba_cb (struct ieee80211_hw * hw, u8 * ra, u8 tid)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw.
ra: receiver address of the BA session recipient.
tid: the desired TID to BA on.

Description

This function must be called by low level driver once it has finished with preparations for the BA session tear down.

ieee80211_stop_tx_ba_cb_irqsafe - low level driver ready to stop aggregate.

void ieee80211_stop_tx_ba_cb_irqsafe (struct ieee80211_hw * hw, const u8 * ra, u16 tid)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw.
ra: receiver address of the BA session recipient.
tid: the desired TID to BA on.

Description

This function must be called by low level driver once it has finished with preparations for the BA session tear down. This version of the function is IRQ-safe.

ieee80211_find_sta - find a station

struct ieee80211_sta * ieee80211_find_sta (struct ieee80211_hw * hw, const u8 * addr)

Arguments

hw: pointer as obtained from ieee80211_alloc_hw
addr: station's address

Description

This function must be called under RCU lock and the resulting pointer is only valid under RCU lock as well.

ieee80211_beacon_loss - inform hardware does not receive beacons

void ieee80211_beacon_loss (struct ieee80211_vif * vif)

Arguments

vif: struct ieee80211_vif pointer from struct ieee80211_if_init_conf.

Description

When beacon filtering is enabled with IEEE80211_HW_BEACON_FILTERING and IEEE80211_CONF_PS is set, the driver needs to inform whenever the hardware is not receiving beacons with this function.

enum rate_control_changed

enum rate_control_changed {
IEEE80211_RC_HT_CHANGED
};

Constants

IEEE80211_RC_HT_CHANGED: The HT parameters of the operating channel have changed, rate control algorithm can update its internal state if needed.

struct ieee80211_tx_rate_control - rate control information for/from RC algo

struct ieee80211_tx_rate_control {
struct ieee80211_hw * hw;
struct ieee80211_supported_band * sband;
struct ieee80211_bss_conf * bss_conf;
struct sk_buff * skb;
struct ieee80211_tx_rate reported_rate;
bool rts;
bool short_preamble;
u8 max_rate_idx;
};

Members

hw: The hardware the algorithm is invoked for.
sband: The band this frame is being transmitted on.
bss_conf: the current BSS configuration
skb: the skb that will be transmitted, the control information in it needs to be filled in
reported_rate: The rate control algorithm can fill this in to indicate which rate should be reported to userspace as the current rate and used for rate calculations in the mesh network.
rts: whether RTS will be used for this frame because it is longer than the RTS threshold
short_preamble: whether mac80211 will request short-preamble transmission if the selected rate supports it
max_rate_idx: user-requested maximum rate (not MCS for now)