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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 cfg80211_beacon_data
111 !Finclude/net/cfg80211.h cfg80211_ap_settings
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_send_rx_assoc
133 !Finclude/net/cfg80211.h cfg80211_send_assoc_timeout
134 !Finclude/net/cfg80211.h cfg80211_send_deauth
135 !Finclude/net/cfg80211.h __cfg80211_send_deauth
136 !Finclude/net/cfg80211.h cfg80211_send_disassoc
137 !Finclude/net/cfg80211.h __cfg80211_send_disassoc
138 !Finclude/net/cfg80211.h cfg80211_ibss_joined
139 !Finclude/net/cfg80211.h cfg80211_connect_result
140 !Finclude/net/cfg80211.h cfg80211_roamed
141 !Finclude/net/cfg80211.h cfg80211_disconnected
142 !Finclude/net/cfg80211.h cfg80211_ready_on_channel
143 !Finclude/net/cfg80211.h cfg80211_remain_on_channel_expired
144 !Finclude/net/cfg80211.h cfg80211_new_sta
145 !Finclude/net/cfg80211.h cfg80211_rx_mgmt
146 !Finclude/net/cfg80211.h cfg80211_mgmt_tx_status
147 !Finclude/net/cfg80211.h cfg80211_cqm_rssi_notify
148 !Finclude/net/cfg80211.h cfg80211_cqm_pktloss_notify
149 !Finclude/net/cfg80211.h cfg80211_michael_mic_failure
152 <title>Scanning and BSS list handling</title>
153 !Pinclude/net/cfg80211.h Scanning and BSS list handling
154 !Finclude/net/cfg80211.h cfg80211_ssid
155 !Finclude/net/cfg80211.h cfg80211_scan_request
156 !Finclude/net/cfg80211.h cfg80211_scan_done
157 !Finclude/net/cfg80211.h cfg80211_bss
158 !Finclude/net/cfg80211.h cfg80211_inform_bss_frame
159 !Finclude/net/cfg80211.h cfg80211_inform_bss
160 !Finclude/net/cfg80211.h cfg80211_unlink_bss
161 !Finclude/net/cfg80211.h cfg80211_find_ie
162 !Finclude/net/cfg80211.h ieee80211_bss_get_ie
165 <title>Utility functions</title>
166 !Pinclude/net/cfg80211.h Utility functions
167 !Finclude/net/cfg80211.h ieee80211_channel_to_frequency
168 !Finclude/net/cfg80211.h ieee80211_frequency_to_channel
169 !Finclude/net/cfg80211.h ieee80211_get_channel
170 !Finclude/net/cfg80211.h ieee80211_get_response_rate
171 !Finclude/net/cfg80211.h ieee80211_hdrlen
172 !Finclude/net/cfg80211.h ieee80211_get_hdrlen_from_skb
173 !Finclude/net/cfg80211.h ieee80211_radiotap_iterator
176 <title>Data path helpers</title>
177 !Pinclude/net/cfg80211.h Data path helpers
178 !Finclude/net/cfg80211.h ieee80211_data_to_8023
179 !Finclude/net/cfg80211.h ieee80211_data_from_8023
180 !Finclude/net/cfg80211.h ieee80211_amsdu_to_8023s
181 !Finclude/net/cfg80211.h cfg80211_classify8021d
184 <title>Regulatory enforcement infrastructure</title>
185 !Pinclude/net/cfg80211.h Regulatory enforcement infrastructure
186 !Finclude/net/cfg80211.h regulatory_hint
187 !Finclude/net/cfg80211.h wiphy_apply_custom_regulatory
188 !Finclude/net/cfg80211.h freq_reg_info
191 <title>RFkill integration</title>
192 !Pinclude/net/cfg80211.h RFkill integration
193 !Finclude/net/cfg80211.h wiphy_rfkill_set_hw_state
194 !Finclude/net/cfg80211.h wiphy_rfkill_start_polling
195 !Finclude/net/cfg80211.h wiphy_rfkill_stop_polling
198 <title>Test mode</title>
199 !Pinclude/net/cfg80211.h Test mode
200 !Finclude/net/cfg80211.h cfg80211_testmode_alloc_reply_skb
201 !Finclude/net/cfg80211.h cfg80211_testmode_reply
202 !Finclude/net/cfg80211.h cfg80211_testmode_alloc_event_skb
203 !Finclude/net/cfg80211.h cfg80211_testmode_event
206 <book id="mac80211-developers-guide">
208 <title>The mac80211 subsystem</title>
210 !Pinclude/net/mac80211.h Introduction
211 !Pinclude/net/mac80211.h Warning
218 Generally, this document shall be ordered by increasing complexity.
219 It is important to note that readers should be able to read only
220 the first few sections to get a working driver and only advanced
221 usage should require reading the full document.
225 <title>The basic mac80211 driver interface</title>
228 You should read and understand the information contained
229 within this part of the book while implementing a driver.
230 In some chapters, advanced usage is noted, that may be
234 This part of the book only covers station and monitor mode
235 functionality, additional information required to implement
236 the other modes is covered in the second part of the book.
240 <chapter id="basics">
241 <title>Basic hardware handling</title>
244 This chapter shall contain information on getting a hw
245 struct allocated and registered with mac80211.
248 Since it is required to allocate rates/modes before registering
249 a hw struct, this chapter shall also contain information on setting
250 up the rate/mode structs.
253 Additionally, some discussion about the callbacks and
254 the general programming model should be in here, including
255 the definition of ieee80211_ops which will be referred to
259 Finally, a discussion of hardware capabilities should be done
260 with references to other parts of the book.
262 <!-- intentionally multiple !F lines to get proper order -->
263 !Finclude/net/mac80211.h ieee80211_hw
264 !Finclude/net/mac80211.h ieee80211_hw_flags
265 !Finclude/net/mac80211.h SET_IEEE80211_DEV
266 !Finclude/net/mac80211.h SET_IEEE80211_PERM_ADDR
267 !Finclude/net/mac80211.h ieee80211_ops
268 !Finclude/net/mac80211.h ieee80211_alloc_hw
269 !Finclude/net/mac80211.h ieee80211_register_hw
270 !Finclude/net/mac80211.h ieee80211_unregister_hw
271 !Finclude/net/mac80211.h ieee80211_free_hw
274 <chapter id="phy-handling">
275 <title>PHY configuration</title>
278 This chapter should describe PHY handling including
279 start/stop callbacks and the various structures used.
281 !Finclude/net/mac80211.h ieee80211_conf
282 !Finclude/net/mac80211.h ieee80211_conf_flags
285 <chapter id="iface-handling">
286 <title>Virtual interfaces</title>
289 This chapter should describe virtual interface basics
290 that are relevant to the driver (VLANs, MGMT etc are not.)
291 It should explain the use of the add_iface/remove_iface
292 callbacks as well as the interface configuration callbacks.
294 <para>Things related to AP mode should be discussed there.</para>
296 Things related to supporting multiple interfaces should be
297 in the appropriate chapter, a BIG FAT note should be here about
298 this though and the recommendation to allow only a single
299 interface in STA mode at first!
301 !Finclude/net/mac80211.h ieee80211_vif
305 <title>Receive and transmit processing</title>
307 <title>what should be here</title>
310 This should describe the receive and transmit
311 paths in mac80211/the drivers as well as
312 transmit status handling.
316 <title>Frame format</title>
317 !Pinclude/net/mac80211.h Frame format
320 <title>Packet alignment</title>
321 !Pnet/mac80211/rx.c Packet alignment
324 <title>Calling into mac80211 from interrupts</title>
325 !Pinclude/net/mac80211.h Calling mac80211 from interrupts
328 <title>functions/definitions</title>
329 !Finclude/net/mac80211.h ieee80211_rx_status
330 !Finclude/net/mac80211.h mac80211_rx_flags
331 !Finclude/net/mac80211.h mac80211_tx_control_flags
332 !Finclude/net/mac80211.h mac80211_rate_control_flags
333 !Finclude/net/mac80211.h ieee80211_tx_rate
334 !Finclude/net/mac80211.h ieee80211_tx_info
335 !Finclude/net/mac80211.h ieee80211_tx_info_clear_status
336 !Finclude/net/mac80211.h ieee80211_rx
337 !Finclude/net/mac80211.h ieee80211_rx_ni
338 !Finclude/net/mac80211.h ieee80211_rx_irqsafe
339 !Finclude/net/mac80211.h ieee80211_tx_status
340 !Finclude/net/mac80211.h ieee80211_tx_status_ni
341 !Finclude/net/mac80211.h ieee80211_tx_status_irqsafe
342 !Finclude/net/mac80211.h ieee80211_rts_get
343 !Finclude/net/mac80211.h ieee80211_rts_duration
344 !Finclude/net/mac80211.h ieee80211_ctstoself_get
345 !Finclude/net/mac80211.h ieee80211_ctstoself_duration
346 !Finclude/net/mac80211.h ieee80211_generic_frame_duration
347 !Finclude/net/mac80211.h ieee80211_wake_queue
348 !Finclude/net/mac80211.h ieee80211_stop_queue
349 !Finclude/net/mac80211.h ieee80211_wake_queues
350 !Finclude/net/mac80211.h ieee80211_stop_queues
351 !Finclude/net/mac80211.h ieee80211_queue_stopped
355 <chapter id="filters">
356 <title>Frame filtering</title>
357 !Pinclude/net/mac80211.h Frame filtering
358 !Finclude/net/mac80211.h ieee80211_filter_flags
361 <chapter id="workqueue">
362 <title>The mac80211 workqueue</title>
363 !Pinclude/net/mac80211.h mac80211 workqueue
364 !Finclude/net/mac80211.h ieee80211_queue_work
365 !Finclude/net/mac80211.h ieee80211_queue_delayed_work
370 <title>Advanced driver interface</title>
373 Information contained within this part of the book is
374 of interest only for advanced interaction of mac80211
375 with drivers to exploit more hardware capabilities and
380 <chapter id="led-support">
381 <title>LED support</title>
383 Mac80211 supports various ways of blinking LEDs. Wherever possible,
384 device LEDs should be exposed as LED class devices and hooked up to
385 the appropriate trigger, which will then be triggered appropriately
388 !Finclude/net/mac80211.h ieee80211_get_tx_led_name
389 !Finclude/net/mac80211.h ieee80211_get_rx_led_name
390 !Finclude/net/mac80211.h ieee80211_get_assoc_led_name
391 !Finclude/net/mac80211.h ieee80211_get_radio_led_name
392 !Finclude/net/mac80211.h ieee80211_tpt_blink
393 !Finclude/net/mac80211.h ieee80211_tpt_led_trigger_flags
394 !Finclude/net/mac80211.h ieee80211_create_tpt_led_trigger
397 <chapter id="hardware-crypto-offload">
398 <title>Hardware crypto acceleration</title>
399 !Pinclude/net/mac80211.h Hardware crypto acceleration
400 <!-- intentionally multiple !F lines to get proper order -->
401 !Finclude/net/mac80211.h set_key_cmd
402 !Finclude/net/mac80211.h ieee80211_key_conf
403 !Finclude/net/mac80211.h ieee80211_key_flags
404 !Finclude/net/mac80211.h ieee80211_get_tkip_p1k
405 !Finclude/net/mac80211.h ieee80211_get_tkip_p1k_iv
406 !Finclude/net/mac80211.h ieee80211_get_tkip_p2k
409 <chapter id="powersave">
410 <title>Powersave support</title>
411 !Pinclude/net/mac80211.h Powersave support
414 <chapter id="beacon-filter">
415 <title>Beacon filter support</title>
416 !Pinclude/net/mac80211.h Beacon filter support
417 !Finclude/net/mac80211.h ieee80211_beacon_loss
421 <title>Multiple queues and QoS support</title>
423 !Finclude/net/mac80211.h ieee80211_tx_queue_params
427 <title>Access point mode support</title>
429 <para>Some parts of the if_conf should be discussed here instead</para>
431 Insert notes about VLAN interfaces with hw crypto here or
432 in the hw crypto chapter.
434 <section id="ps-client">
435 <title>support for powersaving clients</title>
436 !Pinclude/net/mac80211.h AP support for powersaving clients
438 !Finclude/net/mac80211.h ieee80211_get_buffered_bc
439 !Finclude/net/mac80211.h ieee80211_beacon_get
440 !Finclude/net/mac80211.h ieee80211_sta_eosp
441 !Finclude/net/mac80211.h ieee80211_frame_release_type
442 !Finclude/net/mac80211.h ieee80211_sta_ps_transition
443 !Finclude/net/mac80211.h ieee80211_sta_ps_transition_ni
444 !Finclude/net/mac80211.h ieee80211_sta_set_buffered
445 !Finclude/net/mac80211.h ieee80211_sta_block_awake
448 <chapter id="multi-iface">
449 <title>Supporting multiple virtual interfaces</title>
452 Note: WDS with identical MAC address should almost always be OK
455 Insert notes about having multiple virtual interfaces with
456 different MAC addresses here, note which configurations are
457 supported by mac80211, add notes about supporting hw crypto
460 !Finclude/net/mac80211.h ieee80211_iterate_active_interfaces
461 !Finclude/net/mac80211.h ieee80211_iterate_active_interfaces_atomic
464 <chapter id="station-handling">
465 <title>Station handling</title>
467 !Finclude/net/mac80211.h ieee80211_sta
468 !Finclude/net/mac80211.h sta_notify_cmd
469 !Finclude/net/mac80211.h ieee80211_find_sta
470 !Finclude/net/mac80211.h ieee80211_find_sta_by_ifaddr
473 <chapter id="hardware-scan-offload">
474 <title>Hardware scan offload</title>
476 !Finclude/net/mac80211.h ieee80211_scan_completed
479 <chapter id="aggregation">
480 <title>Aggregation</title>
482 <title>TX A-MPDU aggregation</title>
483 !Pnet/mac80211/agg-tx.c TX A-MPDU aggregation
484 !Cnet/mac80211/agg-tx.c
487 <title>RX A-MPDU aggregation</title>
488 !Pnet/mac80211/agg-rx.c RX A-MPDU aggregation
489 !Cnet/mac80211/agg-rx.c
491 !Finclude/net/mac80211.h ieee80211_ampdu_mlme_action
495 <title>Spatial Multiplexing Powersave (SMPS)</title>
496 !Pinclude/net/mac80211.h Spatial multiplexing power save
497 !Finclude/net/mac80211.h ieee80211_request_smps
498 !Finclude/net/mac80211.h ieee80211_smps_mode
502 <part id="rate-control">
503 <title>Rate control interface</title>
507 This part of the book describes the rate control algorithm
508 interface and how it relates to mac80211 and drivers.
511 <chapter id="ratecontrol-api">
512 <title>Rate Control API</title>
514 !Finclude/net/mac80211.h ieee80211_start_tx_ba_session
515 !Finclude/net/mac80211.h ieee80211_start_tx_ba_cb_irqsafe
516 !Finclude/net/mac80211.h ieee80211_stop_tx_ba_session
517 !Finclude/net/mac80211.h ieee80211_stop_tx_ba_cb_irqsafe
518 !Finclude/net/mac80211.h ieee80211_rate_control_changed
519 !Finclude/net/mac80211.h ieee80211_tx_rate_control
520 !Finclude/net/mac80211.h rate_control_send_low
525 <title>Internals</title>
529 This part of the book describes mac80211 internals.
533 <chapter id="key-handling">
534 <title>Key handling</title>
536 <title>Key handling basics</title>
537 !Pnet/mac80211/key.c Key handling basics
540 <title>MORE TBD</title>
545 <chapter id="rx-processing">
546 <title>Receive processing</title>
550 <chapter id="tx-processing">
551 <title>Transmit processing</title>
555 <chapter id="sta-info">
556 <title>Station info handling</title>
558 <title>Programming information</title>
559 !Fnet/mac80211/sta_info.h sta_info
560 !Fnet/mac80211/sta_info.h ieee80211_sta_info_flags
563 <title>STA information lifetime rules</title>
564 !Pnet/mac80211/sta_info.c STA information lifetime rules
568 <chapter id="aggregation-internals">
569 <title>Aggregation</title>
570 !Fnet/mac80211/sta_info.h sta_ampdu_mlme
571 !Fnet/mac80211/sta_info.h tid_ampdu_tx
572 !Fnet/mac80211/sta_info.h tid_ampdu_rx
575 <chapter id="synchronisation">
576 <title>Synchronisation</title>
578 <para>Locking, lots of RCU</para>