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 function.

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_phymode

Constants

MODE_IEEE80211A

5GHz as defined by 802.11a/802.11h

MODE_IEEE80211B

2.4 GHz as defined by 802.11b

MODE_IEEE80211G

2.4 GHz as defined by 802.11g (with OFDM), backwards compatible with 11b mode

NUM_IEEE80211_MODES

internal

Frame format

struct ieee80211_hw_mode - PHY mode definition

Members

list

internal

channels

pointer to array of supported channels

rates

pointer to array of supported bitrates

mode

the PHY mode for this definition

num_channels

number of supported channels

num_rates

number of supported bitrates

Description

This structure describes the capabilities supported by the device in a single PHY mode.

struct ieee80211_tx_queue_params - transmit queue configuration

Members

aifs

arbitration interface space [0..255, -1: use default]

cw_min

minimum contention window [will be a value of the form 2^n-1 in the range 1..1023; 0: use default]

cw_max

maximum contention window [like cw_min]

burst_time

maximum burst time in units of 0.1ms, 0 meaning disabled

Description

The information provided in this structure is required for QoS transmit queue configuration.

struct ieee80211_tx_queue_stats_data - transmit queue statistics

Members

len

number of packets in queue

limit

queue length limit

count

number of frames sent

Description

enum ieee80211_tx_queue

Constants

IEEE80211_TX_QUEUE_DATA0

data queue 0

IEEE80211_TX_QUEUE_DATA1

data queue 1

IEEE80211_TX_QUEUE_DATA2

data queue 2

IEEE80211_TX_QUEUE_DATA3

data queue 3

IEEE80211_TX_QUEUE_DATA4

data queue 4

IEEE80211_TX_QUEUE_SVP

??

NUM_TX_DATA_QUEUES

number of data queues

IEEE80211_TX_QUEUE_AFTER_BEACON

transmit queue for frames to be sent after a beacon

IEEE80211_TX_QUEUE_BEACON

transmit queue for beacon frames

Description

These constants are used with some callbacks that take a queue number to set parameters for a queue.

enum mac80211_rx_flags

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.

Description

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

struct ieee80211_rx_status - receive status

Members

mactime

MAC timestamp as defined by 802.11

freq

frequency the radio was tuned to when receiving this frame, in MHz

channel

channel the radio was tuned to

phymode

active PHY mode

ssi

signal strength when receiving this frame

signal

used as 'qual' in statistics reporting

noise

PHY noise when receiving this frame

antenna

antenna used

rate

data rate

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_tx_status_flags

Constants

IEEE80211_TX_STATUS_TX_FILTERED

The frame was not transmitted because the destination STA was in powersave mode.

IEEE80211_TX_STATUS_ACK

Frame was acknowledged

Description

Status flags to indicate various transmit conditions.

struct ieee80211_tx_status - transmit status

Members

control

a copy of the struct ieee80211_tx_control passed to the driver in the tx callback.

flags

transmit status flags, defined above

excessive_retries

set to 1 if the frame was retried many times but not acknowledged

retry_count

number of retries

ack_signal

signal strength of the ACK frame

queue_length

?? REMOVE

queue_number

?? REMOVE

Description

As much information as possible should be provided for each transmitted frame with ieee80211_tx_status.

enum ieee80211_conf_flags

Constants

IEEE80211_CONF_SHORT_SLOT_TIME

use 802.11g short slot time

IEEE80211_CONF_RADIOTAP

add radiotap header at receive time (if supported)

Description

Flags to define PHY configuration options

struct ieee80211_conf - configuration of the device

Members

channel

IEEE 802.11 channel number

freq

frequency in MHz

channel_val

hardware specific channel value for the channel

phymode

PHY mode to activate (REMOVE)

chan

channel to switch to, pointer to the channel information

mode

pointer to mode definition

regulatory_domain

??

radio_enabled

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

beacon_int

beacon interval (TODO make interface config)

flags

configuration flags defined above

power_level

transmit power limit for current regulatory domain in dBm

antenna_max

maximum antenna gain

antenna_sel_tx

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

antenna_sel_rx

receive antenna selection, like antenna_sel_tx

Description

This struct indicates how the driver shall configure the hardware.

enum ieee80211_if_types

Constants

IEEE80211_IF_TYPE_AP

interface in AP mode.

IEEE80211_IF_TYPE_MGMT

special interface for communication with hostap daemon. Drivers should never see this type.

IEEE80211_IF_TYPE_STA

interface in STA (client) mode.

IEEE80211_IF_TYPE_IBSS

interface in IBSS (ad-hoc) mode.

IEEE80211_IF_TYPE_MNTR

interface in monitor (rfmon) mode.

IEEE80211_IF_TYPE_WDS

interface in WDS mode.

IEEE80211_IF_TYPE_VLAN

VLAN interface bound to an AP, drivers will never see this type.

Description

struct ieee80211_if_init_conf - initial configuration of an interface

Members

if_id

internal interface ID. This number has no particular meaning to drivers and the only allowed usage is to pass it to ieee80211_beacon_get and ieee80211_get_buffered_bc functions. This field is not valid for monitor interfaces (interfaces of IEEE80211_IF_TYPE_MNTR type).

type

one of enum ieee80211_if_types constants. Determines the type of added/removed interface.

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.

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.

struct ieee80211_if_conf - configuration of an interface

Members

type

type of the interface. This is always the same as was specified in struct ieee80211_if_init_conf. The type of an interface never changes during the life of the interface; this field is present only for convenience.

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.

generic_elem

used (together with generic_elem_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.

generic_elem_len

length of the generic element.

beacon

beacon template. Valid only if host_gen_beacon_template in struct ieee80211_hw is set. The driver is responsible of freeing the sk_buff.

beacon_control

tx_control for the beacon template, this field is only valid when the beacon field was set.

Description

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

Description

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

enum ieee80211_key_alg

Constants

ALG_NONE

Unset key algorithm, will never be passed to the driver

ALG_WEP

WEP40 or WEP104

ALG_TKIP

TKIP

ALG_CCMP

CCMP (AES)

enum ieee80211_key_flags

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.

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

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

Description

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

enum set_key_cmd

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.

enum ieee80211_hw_flags

Constants

IEEE80211_HW_HOST_GEN_BEACON_TEMPLATE

The device only needs to be supplied with a beacon template. If you need the host to generate each beacon then don't use this flag and call ieee80211_beacon_get when you need the next beacon frame. Note that if you set this flag, you must implement the set_tim callback for powersave mode to work properly. This flag is only relevant for access-point mode.

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. Note that not setting this flag works properly only when the IEEE80211_HW_HOST_GEN_BEACON_TEMPLATE is also not set because otherwise the stack will not know when the DTIM beacon was sent.

IEEE80211_HW_MULTICAST_FILTER

Device has multicast filters, i.e. it can filter based on the multicast address. If this flag is clear, then FIF_ALLMULTI will be enabled instead of passing multicast addresses when multicast addresses are added.

IEEE80211_HW_DEFAULT_REG_DOMAIN_CONFIGURED

Channels are already configured to the default regulatory domain specified in the device's EEPROM

IEEE80211_HW_SUPPORT_HT_MODE

The device capable of supporting 11n.

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

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.

workqueue

single threaded workqueue available for driver use, allocated by mac80211 on registration and flushed on unregistration.

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.

queues

number of available hardware transmit queues for data packets. WMM/QoS requires at least four.

max_rssi

Maximum value for ssi in RX information, use negative numbers for dBm and 0 to indicate no support.

max_signal

like max_rssi, but for the signal value.

max_noise

like max_rssi, but for the noise value.

Description

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

SET_IEEE80211_DEV - set device for 802.11 hardware

Arguments

hw

the struct ieee80211_hw to set the device for

dev

the struct device of this 802.11 device

Description

SET_IEEE80211_PERM_ADDR - set the permanenet MAC address for 802.11 hardware

Arguments

hw

the struct ieee80211_hw to set the MAC address for

addr

the address to set

Description

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.

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.

If the device is capable of filtering for multicast addresses, you should set the IEEE80211_HW_MULTICAST_FILTER flag in the hardware description.

The configure_filter callback is invoked with the parameters multi_count telling how many multicast addresses are enabled, changed_flags telling which flags were changed, and total_flags telling the new flag state.

Due to the places that configure_filter can be called from, it is possible that it is called with -1 as the multi_count. In that case, the multicast list should not be changed. Otherwise, call ieee80211_get_mc_list_item to get the multicast addresses to let through.

All unsupported flags in total_flags must be cleared, i.e. you should clear all bits except those you honoured.

enum ieee80211_filter_flags

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_erp_change_flags

Constants

IEEE80211_ERP_CHANGE_PROTECTION

protection changed

IEEE80211_ERP_CHANGE_PREAMBLE

barker preamble mode changed

Description

These flags are used with the erp_ie_changed callback in struct ieee80211_ops to indicate which parameter(s) changed.

struct ieee80211_ops - callbacks from mac80211 to the driver

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. 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.)

configure_filter

Configure the device's RX filter. See the section "Frame filtering" for more information. This callback must be implemented and atomic (due to running under the tx lock.)

set_tim

Set TIM bit. If the hardware/firmware takes care of beacon generation (that is, IEEE80211_HW_HOST_GEN_BEACON_TEMPLATE is set) mac80211 calls this function when a TIM bit must be set or cleared for a given AID. 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.

set_ieee8021x

Enable/disable IEEE 802.1X. This item requests wlan card to pass unencrypted EAPOL-Key frames even when encryption is configured. If the wlan card does not require such a configuration, this function pointer can be set to NULL.

set_port_auth

Set port authorization state (IEEE 802.1X PAE) to be authorized (authorized=1) or unauthorized (=0). This function can be used if the wlan hardware or low-level driver implements PAE. mac80211 will filter frames based on authorization state in any case, so this function pointer can be NULL if low-level driver does not require event notification about port state changes.

hw_scan

Ask the hardware to service the scan request, no need to start the scan state machine in stack.

get_stats

return low-level statistics

set_privacy_invoked

For devices that generate their own beacons and probe response or association responses this updates the state of privacy_invoked returns 0 for success or an error number.

get_sequence_counter

For devices that have internal sequence counters this callback allows mac80211 to access the current value of a counter. This callback seems not well-defined, tell us if you need it.

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_table_notification

Number of STAs in STA table notification. Must be atomic.

erp_ie_changed

Handle ERP IE change notifications. Must be atomic.

conf_tx

Configure TX queue parameters (EDCF (aifs, cw_min, cw_max), bursting) for a hardware TX queue. The queue parameter uses the IEEE80211_TX_QUEUE_* constants. Must be atomic.

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). This information is used for WMM to find out which TX queues have room for more packets and by hostapd to provide statistics about the current queueing state to external programs.

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.

handle_ba_action

Call low level driver with 11n Block Ack action

conf_ht

Configure HT parameters.

get_ht_capab

Get HT capabilities from the device

beacon_update

Setup beacon data for IBSS beacons. Unlike access point, IBSS uses a fixed beacon frame which is configured using this function. This handler is required only for IBSS mode.

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.

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

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

Arguments

hw

the device to register as returned by ieee80211_alloc_hw

Description

You must call this function before any other functions except ieee80211_register_hwmode.

ieee80211_get_tx_led_name - get name of TX LED

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

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_unregister_hw - Unregister a hardware device

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

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_rx - receive frame

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.

ieee80211_rx_irqsafe - receive frame

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 workqueue.)

ieee80211_tx_status - transmit status callback

Arguments

hw

the hardware the frame was transmitted by

skb

the frame that was transmitted, owned by mac80211 after this call

status

status information for 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

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.

ieee80211_beacon_get - beacon generation function

Arguments

hw

pointer obtained from ieee80211_alloc_hw.

if_id

interface ID from struct ieee80211_if_init_conf.

control

will be filled with information needed to send this beacon.

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.

ieee80211_rts_get - RTS frame generation function

Arguments

hw

pointer obtained from ieee80211_alloc_hw.

if_id

interface ID 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_control 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

Arguments

hw

pointer obtained from ieee80211_alloc_hw.

if_id

interface ID 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_control 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

Arguments

hw

pointer obtained from ieee80211_alloc_hw.

if_id

interface ID 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_control 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

Arguments

hw

pointer obtained from ieee80211_alloc_hw.

if_id

interface ID 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_control 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

Arguments

hw

pointer obtained from ieee80211_alloc_hw.

if_id

interface ID from struct ieee80211_if_init_conf.

frame_len

the length of the frame.

rate

the rate (in 100kbps) 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

Arguments

hw

pointer as obtained from ieee80211_alloc_hw.

if_id

interface ID from struct ieee80211_if_init_conf.

control

will be filled with information needed to send returned frame.

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

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_get_hdrlen - get header length from frame control

Arguments

fc

the frame control field (in CPU endianness)

Description

This function returns the 802.11 header length in bytes (not including encryption headers.)

ieee80211_wake_queue - wake specific 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

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_start_queues - start all queues

Arguments

hw

pointer to as obtained from ieee80211_alloc_hw.

Description

Drivers should use this function instead of netif_start_queue.

ieee80211_stop_queues - stop all queues

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

Arguments

hw

pointer as obtained from ieee80211_alloc_hw.

Description

Drivers should use this function instead of netif_wake_queue.

ieee80211_get_mc_list_item - iteration over items in multicast list

Arguments

hw

pointer as obtained from ieee80211_alloc_hw.

prev

value returned by previous call to ieee80211_get_mc_list_item or NULL to start a new iteration.

ptr

pointer to buffer of void * type for internal usage of ieee80211_get_mc_list_item.

Description

Iterates over items in multicast list of given device. To get the first item, pass NULL in prev and in *ptr. In subsequent calls, pass the value returned by previous call in prev. Don't alter *ptr during iteration. When there are no more items, NULL is returned.

ieee80211_scan_completed - completed hardware scan

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.