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6 <title>The
802.11 subsystems
– for kernel developers
</title>
8 Explaining wireless
802.11 networking in the Linux kernel
12 <year>2007-
2009</year>
13 <holder>Johannes Berg
</holder>
18 <firstname>Johannes
</firstname>
19 <surname>Berg
</surname>
21 <address><email>johannes@sipsolutions.net
</email></address>
28 This documentation is free software; you can redistribute
29 it and/or modify it under the terms of the GNU General Public
30 License version
2 as published by the Free Software Foundation.
33 This documentation is distributed in the hope that it will be
34 useful, but WITHOUT ANY WARRANTY; without even the implied
35 warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
36 See the GNU General Public License for more details.
39 You should have received a copy of the GNU General Public
40 License along with this documentation; if not, write to the Free
41 Software Foundation, Inc.,
59 Temple Place, Suite
330, Boston,
45 For more details see the file COPYING in the source
46 distribution of Linux.
52 These books attempt to give a description of the
53 various subsystems that play a role in
802.11 wireless
54 networking in Linux. Since these books are for kernel
55 developers they attempts to document the structures
56 and functions used in the kernel as well as giving a
57 higher-level overview.
60 The reader is expected to be familiar with the
802.11
61 standard as published by the IEEE in
802.11-
2007 (or
62 possibly later versions). References to this standard
63 will be given as
"802.11-2007 8.1.5".
67 <book id=
"cfg80211-developers-guide">
69 <title>The cfg80211 subsystem
</title>
72 !Pinclude/net/cfg80211.h Introduction
76 <title>Device registration
</title>
77 !Pinclude/net/cfg80211.h Device registration
78 !Finclude/net/cfg80211.h ieee80211_band
79 !Finclude/net/cfg80211.h ieee80211_channel_flags
80 !Finclude/net/cfg80211.h ieee80211_channel
81 !Finclude/net/cfg80211.h ieee80211_rate_flags
82 !Finclude/net/cfg80211.h ieee80211_rate
83 !Finclude/net/cfg80211.h ieee80211_sta_ht_cap
84 !Finclude/net/cfg80211.h ieee80211_supported_band
85 !Finclude/net/cfg80211.h cfg80211_signal_type
86 !Finclude/net/cfg80211.h wiphy_params_flags
87 !Finclude/net/cfg80211.h wiphy_flags
88 !Finclude/net/cfg80211.h wiphy
89 !Finclude/net/cfg80211.h wireless_dev
90 !Finclude/net/cfg80211.h wiphy_new
91 !Finclude/net/cfg80211.h wiphy_register
92 !Finclude/net/cfg80211.h wiphy_unregister
93 !Finclude/net/cfg80211.h wiphy_free
95 !Finclude/net/cfg80211.h wiphy_name
96 !Finclude/net/cfg80211.h wiphy_dev
97 !Finclude/net/cfg80211.h wiphy_priv
98 !Finclude/net/cfg80211.h priv_to_wiphy
99 !Finclude/net/cfg80211.h set_wiphy_dev
100 !Finclude/net/cfg80211.h wdev_priv
103 <title>Actions and configuration
</title>
104 !Pinclude/net/cfg80211.h Actions and configuration
105 !Finclude/net/cfg80211.h cfg80211_ops
106 !Finclude/net/cfg80211.h vif_params
107 !Finclude/net/cfg80211.h key_params
108 !Finclude/net/cfg80211.h survey_info_flags
109 !Finclude/net/cfg80211.h survey_info
110 !Finclude/net/cfg80211.h beacon_parameters
111 !Finclude/net/cfg80211.h plink_actions
112 !Finclude/net/cfg80211.h station_parameters
113 !Finclude/net/cfg80211.h station_info_flags
114 !Finclude/net/cfg80211.h rate_info_flags
115 !Finclude/net/cfg80211.h rate_info
116 !Finclude/net/cfg80211.h station_info
117 !Finclude/net/cfg80211.h monitor_flags
118 !Finclude/net/cfg80211.h mpath_info_flags
119 !Finclude/net/cfg80211.h mpath_info
120 !Finclude/net/cfg80211.h bss_parameters
121 !Finclude/net/cfg80211.h ieee80211_txq_params
122 !Finclude/net/cfg80211.h cfg80211_crypto_settings
123 !Finclude/net/cfg80211.h cfg80211_auth_request
124 !Finclude/net/cfg80211.h cfg80211_assoc_request
125 !Finclude/net/cfg80211.h cfg80211_deauth_request
126 !Finclude/net/cfg80211.h cfg80211_disassoc_request
127 !Finclude/net/cfg80211.h cfg80211_ibss_params
128 !Finclude/net/cfg80211.h cfg80211_connect_params
129 !Finclude/net/cfg80211.h cfg80211_pmksa
130 !Finclude/net/cfg80211.h cfg80211_send_rx_auth
131 !Finclude/net/cfg80211.h cfg80211_send_auth_timeout
132 !Finclude/net/cfg80211.h __cfg80211_auth_canceled
133 !Finclude/net/cfg80211.h cfg80211_send_rx_assoc
134 !Finclude/net/cfg80211.h cfg80211_send_assoc_timeout
135 !Finclude/net/cfg80211.h cfg80211_send_deauth
136 !Finclude/net/cfg80211.h __cfg80211_send_deauth
137 !Finclude/net/cfg80211.h cfg80211_send_disassoc
138 !Finclude/net/cfg80211.h __cfg80211_send_disassoc
139 !Finclude/net/cfg80211.h cfg80211_ibss_joined
140 !Finclude/net/cfg80211.h cfg80211_connect_result
141 !Finclude/net/cfg80211.h cfg80211_roamed
142 !Finclude/net/cfg80211.h cfg80211_disconnected
143 !Finclude/net/cfg80211.h cfg80211_ready_on_channel
144 !Finclude/net/cfg80211.h cfg80211_remain_on_channel_expired
145 !Finclude/net/cfg80211.h cfg80211_new_sta
146 !Finclude/net/cfg80211.h cfg80211_rx_mgmt
147 !Finclude/net/cfg80211.h cfg80211_mgmt_tx_status
148 !Finclude/net/cfg80211.h cfg80211_cqm_rssi_notify
149 !Finclude/net/cfg80211.h cfg80211_cqm_pktloss_notify
150 !Finclude/net/cfg80211.h cfg80211_michael_mic_failure
153 <title>Scanning and BSS list handling
</title>
154 !Pinclude/net/cfg80211.h Scanning and BSS list handling
155 !Finclude/net/cfg80211.h cfg80211_ssid
156 !Finclude/net/cfg80211.h cfg80211_scan_request
157 !Finclude/net/cfg80211.h cfg80211_scan_done
158 !Finclude/net/cfg80211.h cfg80211_bss
159 !Finclude/net/cfg80211.h cfg80211_inform_bss_frame
160 !Finclude/net/cfg80211.h cfg80211_inform_bss
161 !Finclude/net/cfg80211.h cfg80211_unlink_bss
162 !Finclude/net/cfg80211.h cfg80211_find_ie
163 !Finclude/net/cfg80211.h ieee80211_bss_get_ie
166 <title>Utility functions
</title>
167 !Pinclude/net/cfg80211.h Utility functions
168 !Finclude/net/cfg80211.h ieee80211_channel_to_frequency
169 !Finclude/net/cfg80211.h ieee80211_frequency_to_channel
170 !Finclude/net/cfg80211.h ieee80211_get_channel
171 !Finclude/net/cfg80211.h ieee80211_get_response_rate
172 !Finclude/net/cfg80211.h ieee80211_hdrlen
173 !Finclude/net/cfg80211.h ieee80211_get_hdrlen_from_skb
174 !Finclude/net/cfg80211.h ieee80211_radiotap_iterator
177 <title>Data path helpers
</title>
178 !Pinclude/net/cfg80211.h Data path helpers
179 !Finclude/net/cfg80211.h ieee80211_data_to_8023
180 !Finclude/net/cfg80211.h ieee80211_data_from_8023
181 !Finclude/net/cfg80211.h ieee80211_amsdu_to_8023s
182 !Finclude/net/cfg80211.h cfg80211_classify8021d
185 <title>Regulatory enforcement infrastructure
</title>
186 !Pinclude/net/cfg80211.h Regulatory enforcement infrastructure
187 !Finclude/net/cfg80211.h regulatory_hint
188 !Finclude/net/cfg80211.h wiphy_apply_custom_regulatory
189 !Finclude/net/cfg80211.h freq_reg_info
192 <title>RFkill integration
</title>
193 !Pinclude/net/cfg80211.h RFkill integration
194 !Finclude/net/cfg80211.h wiphy_rfkill_set_hw_state
195 !Finclude/net/cfg80211.h wiphy_rfkill_start_polling
196 !Finclude/net/cfg80211.h wiphy_rfkill_stop_polling
199 <title>Test mode
</title>
200 !Pinclude/net/cfg80211.h Test mode
201 !Finclude/net/cfg80211.h cfg80211_testmode_alloc_reply_skb
202 !Finclude/net/cfg80211.h cfg80211_testmode_reply
203 !Finclude/net/cfg80211.h cfg80211_testmode_alloc_event_skb
204 !Finclude/net/cfg80211.h cfg80211_testmode_event
207 <book id=
"mac80211-developers-guide">
209 <title>The mac80211 subsystem
</title>
211 !Pinclude/net/mac80211.h Introduction
212 !Pinclude/net/mac80211.h Warning
219 Generally, this document shall be ordered by increasing complexity.
220 It is important to note that readers should be able to read only
221 the first few sections to get a working driver and only advanced
222 usage should require reading the full document.
226 <title>The basic mac80211 driver interface
</title>
229 You should read and understand the information contained
230 within this part of the book while implementing a driver.
231 In some chapters, advanced usage is noted, that may be
235 This part of the book only covers station and monitor mode
236 functionality, additional information required to implement
237 the other modes is covered in the second part of the book.
241 <chapter id=
"basics">
242 <title>Basic hardware handling
</title>
245 This chapter shall contain information on getting a hw
246 struct allocated and registered with mac80211.
249 Since it is required to allocate rates/modes before registering
250 a hw struct, this chapter shall also contain information on setting
251 up the rate/mode structs.
254 Additionally, some discussion about the callbacks and
255 the general programming model should be in here, including
256 the definition of ieee80211_ops which will be referred to
260 Finally, a discussion of hardware capabilities should be done
261 with references to other parts of the book.
263 <!-- intentionally multiple !F lines to get proper order -->
264 !Finclude/net/mac80211.h ieee80211_hw
265 !Finclude/net/mac80211.h ieee80211_hw_flags
266 !Finclude/net/mac80211.h SET_IEEE80211_DEV
267 !Finclude/net/mac80211.h SET_IEEE80211_PERM_ADDR
268 !Finclude/net/mac80211.h ieee80211_ops
269 !Finclude/net/mac80211.h ieee80211_alloc_hw
270 !Finclude/net/mac80211.h ieee80211_register_hw
271 !Finclude/net/mac80211.h ieee80211_unregister_hw
272 !Finclude/net/mac80211.h ieee80211_free_hw
275 <chapter id=
"phy-handling">
276 <title>PHY configuration
</title>
279 This chapter should describe PHY handling including
280 start/stop callbacks and the various structures used.
282 !Finclude/net/mac80211.h ieee80211_conf
283 !Finclude/net/mac80211.h ieee80211_conf_flags
286 <chapter id=
"iface-handling">
287 <title>Virtual interfaces
</title>
290 This chapter should describe virtual interface basics
291 that are relevant to the driver (VLANs, MGMT etc are not.)
292 It should explain the use of the add_iface/remove_iface
293 callbacks as well as the interface configuration callbacks.
295 <para>Things related to AP mode should be discussed there.
</para>
297 Things related to supporting multiple interfaces should be
298 in the appropriate chapter, a BIG FAT note should be here about
299 this though and the recommendation to allow only a single
300 interface in STA mode at first!
302 !Finclude/net/mac80211.h ieee80211_vif
306 <title>Receive and transmit processing
</title>
308 <title>what should be here
</title>
311 This should describe the receive and transmit
312 paths in mac80211/the drivers as well as
313 transmit status handling.
317 <title>Frame format
</title>
318 !Pinclude/net/mac80211.h Frame format
321 <title>Packet alignment
</title>
322 !Pnet/mac80211/rx.c Packet alignment
325 <title>Calling into mac80211 from interrupts
</title>
326 !Pinclude/net/mac80211.h Calling mac80211 from interrupts
329 <title>functions/definitions
</title>
330 !Finclude/net/mac80211.h ieee80211_rx_status
331 !Finclude/net/mac80211.h mac80211_rx_flags
332 !Finclude/net/mac80211.h mac80211_tx_control_flags
333 !Finclude/net/mac80211.h mac80211_rate_control_flags
334 !Finclude/net/mac80211.h ieee80211_tx_rate
335 !Finclude/net/mac80211.h ieee80211_tx_info
336 !Finclude/net/mac80211.h ieee80211_tx_info_clear_status
337 !Finclude/net/mac80211.h ieee80211_rx
338 !Finclude/net/mac80211.h ieee80211_rx_ni
339 !Finclude/net/mac80211.h ieee80211_rx_irqsafe
340 !Finclude/net/mac80211.h ieee80211_tx_status
341 !Finclude/net/mac80211.h ieee80211_tx_status_ni
342 !Finclude/net/mac80211.h ieee80211_tx_status_irqsafe
343 !Finclude/net/mac80211.h ieee80211_rts_get
344 !Finclude/net/mac80211.h ieee80211_rts_duration
345 !Finclude/net/mac80211.h ieee80211_ctstoself_get
346 !Finclude/net/mac80211.h ieee80211_ctstoself_duration
347 !Finclude/net/mac80211.h ieee80211_generic_frame_duration
348 !Finclude/net/mac80211.h ieee80211_wake_queue
349 !Finclude/net/mac80211.h ieee80211_stop_queue
350 !Finclude/net/mac80211.h ieee80211_wake_queues
351 !Finclude/net/mac80211.h ieee80211_stop_queues
352 !Finclude/net/mac80211.h ieee80211_queue_stopped
356 <chapter id=
"filters">
357 <title>Frame filtering
</title>
358 !Pinclude/net/mac80211.h Frame filtering
359 !Finclude/net/mac80211.h ieee80211_filter_flags
362 <chapter id=
"workqueue">
363 <title>The mac80211 workqueue
</title>
364 !Pinclude/net/mac80211.h mac80211 workqueue
365 !Finclude/net/mac80211.h ieee80211_queue_work
366 !Finclude/net/mac80211.h ieee80211_queue_delayed_work
371 <title>Advanced driver interface
</title>
374 Information contained within this part of the book is
375 of interest only for advanced interaction of mac80211
376 with drivers to exploit more hardware capabilities and
381 <chapter id=
"led-support">
382 <title>LED support
</title>
384 Mac80211 supports various ways of blinking LEDs. Wherever possible,
385 device LEDs should be exposed as LED class devices and hooked up to
386 the appropriate trigger, which will then be triggered appropriately
389 !Finclude/net/mac80211.h ieee80211_get_tx_led_name
390 !Finclude/net/mac80211.h ieee80211_get_rx_led_name
391 !Finclude/net/mac80211.h ieee80211_get_assoc_led_name
392 !Finclude/net/mac80211.h ieee80211_get_radio_led_name
393 !Finclude/net/mac80211.h ieee80211_tpt_blink
394 !Finclude/net/mac80211.h ieee80211_tpt_led_trigger_flags
395 !Finclude/net/mac80211.h ieee80211_create_tpt_led_trigger
398 <chapter id=
"hardware-crypto-offload">
399 <title>Hardware crypto acceleration
</title>
400 !Pinclude/net/mac80211.h Hardware crypto acceleration
401 <!-- intentionally multiple !F lines to get proper order -->
402 !Finclude/net/mac80211.h set_key_cmd
403 !Finclude/net/mac80211.h ieee80211_key_conf
404 !Finclude/net/mac80211.h ieee80211_key_flags
405 !Finclude/net/mac80211.h ieee80211_tkip_key_type
406 !Finclude/net/mac80211.h ieee80211_get_tkip_key
407 !Finclude/net/mac80211.h ieee80211_key_removed
410 <chapter id=
"powersave">
411 <title>Powersave support
</title>
412 !Pinclude/net/mac80211.h Powersave support
415 <chapter id=
"beacon-filter">
416 <title>Beacon filter support
</title>
417 !Pinclude/net/mac80211.h Beacon filter support
418 !Finclude/net/mac80211.h ieee80211_beacon_loss
422 <title>Multiple queues and QoS support
</title>
424 !Finclude/net/mac80211.h ieee80211_tx_queue_params
428 <title>Access point mode support
</title>
430 <para>Some parts of the if_conf should be discussed here instead
</para>
432 Insert notes about VLAN interfaces with hw crypto here or
433 in the hw crypto chapter.
435 !Finclude/net/mac80211.h ieee80211_get_buffered_bc
436 !Finclude/net/mac80211.h ieee80211_beacon_get
439 <chapter id=
"multi-iface">
440 <title>Supporting multiple virtual interfaces
</title>
443 Note: WDS with identical MAC address should almost always be OK
446 Insert notes about having multiple virtual interfaces with
447 different MAC addresses here, note which configurations are
448 supported by mac80211, add notes about supporting hw crypto
451 !Finclude/net/mac80211.h ieee80211_iterate_active_interfaces
452 !Finclude/net/mac80211.h ieee80211_iterate_active_interfaces_atomic
455 <chapter id=
"station-handling">
456 <title>Station handling
</title>
458 !Finclude/net/mac80211.h ieee80211_sta
459 !Finclude/net/mac80211.h sta_notify_cmd
460 !Finclude/net/mac80211.h ieee80211_find_sta
461 !Finclude/net/mac80211.h ieee80211_find_sta_by_ifaddr
462 !Finclude/net/mac80211.h ieee80211_sta_block_awake
465 <chapter id=
"hardware-scan-offload">
466 <title>Hardware scan offload
</title>
468 !Finclude/net/mac80211.h ieee80211_scan_completed
471 <chapter id=
"aggregation">
472 <title>Aggregation
</title>
474 <title>TX A-MPDU aggregation
</title>
475 !Pnet/mac80211/agg-tx.c TX A-MPDU aggregation
476 !Cnet/mac80211/agg-tx.c
479 <title>RX A-MPDU aggregation
</title>
480 !Pnet/mac80211/agg-rx.c RX A-MPDU aggregation
481 !Cnet/mac80211/agg-rx.c
483 !Finclude/net/mac80211.h ieee80211_ampdu_mlme_action
487 <title>Spatial Multiplexing Powersave (SMPS)
</title>
488 !Pinclude/net/mac80211.h Spatial multiplexing power save
489 !Finclude/net/mac80211.h ieee80211_request_smps
490 !Finclude/net/mac80211.h ieee80211_smps_mode
494 <part id=
"rate-control">
495 <title>Rate control interface
</title>
499 This part of the book describes the rate control algorithm
500 interface and how it relates to mac80211 and drivers.
503 <chapter id=
"ratecontrol-api">
504 <title>Rate Control API
</title>
506 !Finclude/net/mac80211.h ieee80211_start_tx_ba_session
507 !Finclude/net/mac80211.h ieee80211_start_tx_ba_cb_irqsafe
508 !Finclude/net/mac80211.h ieee80211_stop_tx_ba_session
509 !Finclude/net/mac80211.h ieee80211_stop_tx_ba_cb_irqsafe
510 !Finclude/net/mac80211.h rate_control_changed
511 !Finclude/net/mac80211.h ieee80211_tx_rate_control
512 !Finclude/net/mac80211.h rate_control_send_low
517 <title>Internals
</title>
521 This part of the book describes mac80211 internals.
525 <chapter id=
"key-handling">
526 <title>Key handling
</title>
528 <title>Key handling basics
</title>
529 !Pnet/mac80211/key.c Key handling basics
532 <title>MORE TBD
</title>
537 <chapter id=
"rx-processing">
538 <title>Receive processing
</title>
542 <chapter id=
"tx-processing">
543 <title>Transmit processing
</title>
547 <chapter id=
"sta-info">
548 <title>Station info handling
</title>
550 <title>Programming information
</title>
551 !Fnet/mac80211/sta_info.h sta_info
552 !Fnet/mac80211/sta_info.h ieee80211_sta_info_flags
555 <title>STA information lifetime rules
</title>
556 !Pnet/mac80211/sta_info.c STA information lifetime rules
560 <chapter id=
"aggregation-internals">
561 <title>Aggregation
</title>
562 !Fnet/mac80211/sta_info.h sta_ampdu_mlme
563 !Fnet/mac80211/sta_info.h tid_ampdu_tx
564 !Fnet/mac80211/sta_info.h tid_ampdu_rx
567 <chapter id=
"synchronisation">
568 <title>Synchronisation
</title>
570 <para>Locking, lots of RCU
</para>