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.

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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!

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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.

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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.

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enum ieee80211_notification_types

enum ieee80211_notification_types {
IEEE80211_NOTIFY_RE_ASSOC
};

Constants

IEEE80211_NOTIFY_RE_ASSOC

start the re-association sequence

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struct ieee80211_ht_bss_info - describing BSS's HT characteristics

struct ieee80211_ht_bss_info {
    u8 primary_channel;
    u8 bss_cap;
    u8 bss_op_mode;
};

Members

primary_channel

channel number of primery channel

bss_cap

802.11n's general BSS capabilities (e.g. channel width)

bss_op_mode

802.11n's BSS operation modes (e.g. HT protection)

Description

This structure describes most essential parameters needed to describe 802.11n HT characteristics in a BSS.

---

enum ieee80211_max_queues

enum ieee80211_max_queues {
IEEE80211_MAX_QUEUES,
IEEE80211_MAX_AMPDU_QUEUES
};

Constants

IEEE80211_MAX_QUEUES

Maximum number of regular device queues.

IEEE80211_MAX_AMPDU_QUEUES

Maximum number of queues usable for A-MPDU operation.

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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 interface 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.

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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
};

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

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 {
    bool assoc;
    u16 aid;
    bool use_cts_prot;
    bool use_short_preamble;
    bool use_short_slot;
    u8 dtim_period;
    u16 beacon_int;
    u16 assoc_capability;
    u64 timestamp;
    u64 basic_rates;
    bool assoc_ht;
    struct ieee80211_ht_info * ht_conf;
    struct ieee80211_ht_bss_info * ht_bss_conf;
};

Members

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

use_short_slot

use short slot time (only relevant for ERP)

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.

assoc_ht

association in HT mode

ht_conf

ht capabilities

ht_bss_conf

ht extended capabilities

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_USE_RTS_CTS,
IEEE80211_TX_CTL_USE_CTS_PROTECT,
IEEE80211_TX_CTL_NO_ACK,
IEEE80211_TX_CTL_RATE_CTRL_PROBE,
IEEE80211_TX_CTL_CLEAR_PS_FILT,
IEEE80211_TX_CTL_REQUEUE,
IEEE80211_TX_CTL_FIRST_FRAGMENT,
IEEE80211_TX_CTL_SHORT_PREAMBLE,
IEEE80211_TX_CTL_LONG_RETRY_LIMIT,
IEEE80211_TX_CTL_SEND_AFTER_DTIM,
IEEE80211_TX_CTL_AMPDU,
IEEE80211_TX_CTL_OFDM_HT,
IEEE80211_TX_CTL_GREEN_FIELD,
IEEE80211_TX_CTL_40_MHZ_WIDTH,
IEEE80211_TX_CTL_DUP_DATA,
IEEE80211_TX_CTL_SHORT_GI,
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_ASSIGN_SEQ
};

Constants

IEEE80211_TX_CTL_REQ_TX_STATUS

request TX status callback for this frame.

IEEE80211_TX_CTL_USE_RTS_CTS

use RTS-CTS before sending frame

IEEE80211_TX_CTL_USE_CTS_PROTECT

use CTS protection for the frame (e.g., for combined 802.11g / 802.11b networks)

IEEE80211_TX_CTL_NO_ACK

tell the low level not to wait for an ack

IEEE80211_TX_CTL_RATE_CTRL_PROBE

TBD

IEEE80211_TX_CTL_CLEAR_PS_FILT

clear powersave filter for destination station

IEEE80211_TX_CTL_REQUEUE

TBD

IEEE80211_TX_CTL_FIRST_FRAGMENT

this is a first fragment of the frame

IEEE80211_TX_CTL_SHORT_PREAMBLE

TBD

IEEE80211_TX_CTL_LONG_RETRY_LIMIT

this frame should be send using the through set_retry_limit configured long retry value

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_OFDM_HT

this frame can be sent in HT OFDM rates. number of streams when this flag is on can be extracted from antenna_sel_tx, so if 1 antenna is marked use SISO, 2 antennas marked use MIMO, n antennas marked use MIMO_n.

IEEE80211_TX_CTL_GREEN_FIELD

use green field protection for this frame

IEEE80211_TX_CTL_40_MHZ_WIDTH

send this frame using 40 Mhz channel width

IEEE80211_TX_CTL_DUP_DATA

duplicate data frame on both 20 Mhz channels

IEEE80211_TX_CTL_SHORT_GI

send this frame using short guard interval

IEEE80211_TX_CTL_INJECTED

TBD

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_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 flags 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 always be clear for frames without a sequence number field.

Description

These flags are used with the flags member of ieee80211_tx_info.

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struct ieee80211_tx_info - skb transmit information

struct ieee80211_tx_info {
    u32 flags;
    u8 band;
    s8 tx_rate_idx;
    u8 antenna_sel_tx;
    union {unnamed_union};
};

Members

flags

transmit info flags, defined above

band

TBD

tx_rate_idx

TBD

antenna_sel_tx

TBD

{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.

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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
};

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

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

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.

---

enum ieee80211_conf_flags

enum ieee80211_conf_flags {
IEEE80211_CONF_SHORT_SLOT_TIME,
IEEE80211_CONF_RADIOTAP,
IEEE80211_CONF_SUPPORT_HT_MODE,
IEEE80211_CONF_PS
};

Constants

IEEE80211_CONF_SHORT_SLOT_TIME

use 802.11g short slot time

IEEE80211_CONF_RADIOTAP

add radiotap header at receive time (if supported)

IEEE80211_CONF_SUPPORT_HT_MODE

use 802.11n HT capabilities (if supported)

IEEE80211_CONF_PS

Enable 802.11 power save mode

Description

Flags to define PHY configuration options

---

struct ieee80211_conf - configuration of the device

struct ieee80211_conf {
    int radio_enabled;
    int beacon_int;
    u16 listen_interval;
    u32 flags;
    int power_level;
    int max_antenna_gain;
    u8 antenna_sel_tx;
    u8 antenna_sel_rx;
    struct ieee80211_channel * channel;
    struct ieee80211_ht_info ht_conf;
    struct ieee80211_ht_bss_info ht_bss_conf;
};

Members

radio_enabled

when zero, driver is required to switch off the radio. TODO make a flag

beacon_int

beacon interval (TODO make interface config)

listen_interval

listen interval in units of beacon interval

flags

configuration flags defined above

power_level

requested transmit power (in dBm)

max_antenna_gain

maximum antenna gain (in dBi)

antenna_sel_tx

transmit antenna selection, 0: default/diversity, 1/2: antenna 0/1

antenna_sel_rx

receive antenna selection, like antenna_sel_tx

channel

the channel to tune to

ht_conf

describes current self configuration of 802.11n HT capabilies

ht_bss_conf

describes current BSS configuration of 802.11n HT parameters

Description

This struct indicates how the driver shall configure the hardware.

---

struct ieee80211_vif - per-interface data

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

Members

type

type of this virtual interface

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_if_conf_change

enum ieee80211_if_conf_change {
IEEE80211_IFCC_BSSID,
IEEE80211_IFCC_SSID,
IEEE80211_IFCC_BEACON
};

Constants

IEEE80211_IFCC_BSSID

The BSSID changed.

IEEE80211_IFCC_SSID

The SSID changed.

IEEE80211_IFCC_BEACON

The beacon for this interface changed (currently AP and MESH only), use ieee80211_beacon_get.

---

struct ieee80211_if_conf - configuration of an interface

struct ieee80211_if_conf {
    u32 changed;
    u8 * bssid;
    u8 * ssid;
    size_t ssid_len;
};

Members

changed

parameters that have changed, see enum ieee80211_if_conf_change.

bssid

BSSID of the network we are associated to/creating.

ssid

used (together with ssid_len) by drivers for hardware that generate beacons independently. The pointer is valid only during the config_interface call, so copy the value somewhere if you need it.

ssid_len

length of the ssid field.

Description

This structure is passed to the config_interface callback of struct ieee80211_hw.

---

enum ieee80211_key_alg

enum ieee80211_key_alg {
ALG_WEP,
ALG_TKIP,
ALG_CCMP
};

Constants

ALG_WEP

WEP40 or WEP104

ALG_TKIP

TKIP

ALG_CCMP

CCMP (AES)

---

enum ieee80211_key_len

enum ieee80211_key_len {
LEN_WEP40,
LEN_WEP104
};

Constants

LEN_WEP40

WEP 5-byte long key

LEN_WEP104

WEP 13-byte long key

---

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
};

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.

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 hw_key_idx;
    u8 flags;
    s8 keyidx;
    u8 keylen;
    u8 key[0];
};

Members

alg

The key algorithm.

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 {
    u64 supp_rates[IEEE80211_NUM_BANDS];
    u8 addr[ETH_ALEN];
    u16 aid;
    struct ieee80211_ht_info ht_info;
    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_info

HT capabilities of this STA

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
};

Constants

STA_NOTIFY_ADD

a station was added to the station table

STA_NOTIFY_REMOVE

a station being removed from the station table

Description

Used with the sta_notify callback in struct ieee80211_ops, this indicates addition and removal of a station to station table.

---

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_DB,
IEEE80211_HW_SIGNAL_DBM,
IEEE80211_HW_NOISE_DBM,
IEEE80211_HW_SPECTRUM_MGMT
};

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_DB

Hardware gives signal values in dB, decibel difference from an arbitrary, fixed reference. We expect values between 0 and max_signal. If possible please provide 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

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 ampdu_queues;
    u16 max_listen_interval;
    s8 max_signal;
};

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.

ampdu_queues

number of available hardware transmit queues for A-MPDU packets, these have no access parameters because they're used only for A-MPDU frames. Note that mac80211 will not currently use any of the regular queues for aggregation.

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

Description

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

NOTICE

All work performed on this workqueue should NEVER acquire the RTNL lock (i.e. Don't use the function ieee80211_iterate_active_interfaces)

---

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 permanenet 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 an address parameter that will be the broadcast address for default keys, the other station's hardware address for individual keys or the zero address for keys that will be used only for transmission. Multiple transmission keys with the same key index may be used when VLANs are configured for an access point.

The local_address parameter will always be set to our own address, this is only relevant if you support multiple local addresses.

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 udpate_tkip_key only. The trigger that makes mac80211 call this handler is software decryption with wrap around of iv16.

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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.

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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.

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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
};

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

Description

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

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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, struct ieee80211_conf *conf);
    int (*config_interface) (struct ieee80211_hw *hw,struct ieee80211_vif *vif,struct ieee80211_if_conf *conf);
    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,const u8 *local_address, const u8 *address,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, u8 *ssid, size_t len);
    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);
    int (*set_frag_threshold) (struct ieee80211_hw *hw, u32 value);
    int (*set_retry_limit) (struct ieee80211_hw *hw,u32 short_retry, u32 long_retr);
    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 (*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);
};

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. 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, open 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.

config_interface

Handler for configuration requests related to interfaces (e.g. BSSID changes.)

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 interface with the given local_address is enabled.

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. When the scan finishes, ieee80211_scan_completed must be called; note that it also must be called when the scan cannot finish because the hardware is turned off! Anything else is a bug!

get_stats

return low-level statistics

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)

set_frag_threshold

Configuration of fragmentation threshold. Assign this if the device does fragmentation by itself; if this method is assigned then the stack will not do fragmentation.

set_retry_limit

Configuration of retry limits (if device needs it)

sta_notify

Notifies low level driver about addition or removal of assocaited station or AP.

conf_tx

Configure TX queue parameters (EDCF (aifs, cw_min, cw_max), bursting) for a hardware TX queue.

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 + hw->ampdu_queues items.

get_tsf

Get the current TSF timer value from firmware/hardware. Currently, this is only used for IBSS mode debugging and, as such, is not a required function. Must be atomic.

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.

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.

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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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ieee80211_rx - receive frame

void ieee80211_rx (struct ieee80211_hw * hw, struct sk_buff * skb, struct ieee80211_rx_status * status)

Arguments

hw

the hardware this frame came in on

skb

the buffer to receive, owned by mac80211 after this call

status

status of this frame; the status pointer need not be valid after this function returns

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.

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ieee80211_rx_irqsafe - receive frame

void ieee80211_rx_irqsafe (struct ieee80211_hw * hw, struct sk_buff * skb, struct ieee80211_rx_status * status)

Arguments

hw

the hardware this frame came in on

skb

the buffer to receive, owned by mac80211 after this call

status

status of this frame; the status pointer need not be valid after this function returns and is not freed by mac80211, it is recommended that it points to a stack area

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.

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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.

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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.

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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 of freeing it.

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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.

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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.

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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).

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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_hdrlen_from_skb - get header length from data

unsigned int ieee80211_get_hdrlen_from_skb (const struct sk_buff * skb)

Arguments

skb

the frame

Description

Given an skb with a raw 802.11 header at the data pointer this function returns the 802.11 header length in bytes (not including encryption headers). If the data in the sk_buff is too short to contain a valid 802.11 header the function returns 0.

---

ieee80211_hdrlen - get header length in bytes from frame control

unsigned int ieee80211_hdrlen (__le16 fc)

Arguments

fc

frame control field in little-endian format

---

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

TBD

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)

Arguments

hw

the hardware that finished the scan

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.

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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.

Description

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.

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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.

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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.

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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.

Description

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.

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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.

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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.

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ieee80211_notify_mac - low level driver notification

void ieee80211_notify_mac (struct ieee80211_hw * hw, enum ieee80211_notification_types notif_type)

Arguments

hw

pointer as obtained from ieee80211_alloc_hw.

notif_type

enum ieee80211_notification_types

Description

This function must be called by low level driver to inform mac80211 of low level driver status change or force mac80211 to re-assoc for low level driver internal error that require re-assoc.

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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.

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struct rate_selection - rate information for/from rate control algorithms

struct rate_selection {
    s8 rate_idx;
    s8 nonerp_idx;
    s8 probe_idx;
    s8 max_rate_idx;
};

Members

rate_idx

selected transmission rate index

nonerp_idx

Non-ERP rate to use instead if ERP cannot be used

probe_idx

rate for probing (or -1)

max_rate_idx

maximum rate index that can be used, this is input to the algorithm and will be enforced

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