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TOMOYO Linux Cross Reference
Linux/net/mac80211/offchannel.c

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  1 /*
  2  * Off-channel operation helpers
  3  *
  4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
  5  * Copyright 2004, Instant802 Networks, Inc.
  6  * Copyright 2005, Devicescape Software, Inc.
  7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
  8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
  9  * Copyright 2009       Johannes Berg <johannes@sipsolutions.net>
 10  *
 11  * This program is free software; you can redistribute it and/or modify
 12  * it under the terms of the GNU General Public License version 2 as
 13  * published by the Free Software Foundation.
 14  */
 15 #include <linux/export.h>
 16 #include <net/mac80211.h>
 17 #include "ieee80211_i.h"
 18 #include "driver-ops.h"
 19 
 20 /*
 21  * Tell our hardware to disable PS.
 22  * Optionally inform AP that we will go to sleep so that it will buffer
 23  * the frames while we are doing off-channel work.  This is optional
 24  * because we *may* be doing work on-operating channel, and want our
 25  * hardware unconditionally awake, but still let the AP send us normal frames.
 26  */
 27 static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata)
 28 {
 29         struct ieee80211_local *local = sdata->local;
 30         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
 31 
 32         local->offchannel_ps_enabled = false;
 33 
 34         /* FIXME: what to do when local->pspolling is true? */
 35 
 36         del_timer_sync(&local->dynamic_ps_timer);
 37         del_timer_sync(&ifmgd->bcn_mon_timer);
 38         del_timer_sync(&ifmgd->conn_mon_timer);
 39 
 40         cancel_work_sync(&local->dynamic_ps_enable_work);
 41 
 42         if (local->hw.conf.flags & IEEE80211_CONF_PS) {
 43                 local->offchannel_ps_enabled = true;
 44                 local->hw.conf.flags &= ~IEEE80211_CONF_PS;
 45                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
 46         }
 47 
 48         if (!local->offchannel_ps_enabled ||
 49             !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
 50                 /*
 51                  * If power save was enabled, no need to send a nullfunc
 52                  * frame because AP knows that we are sleeping. But if the
 53                  * hardware is creating the nullfunc frame for power save
 54                  * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
 55                  * enabled) and power save was enabled, the firmware just
 56                  * sent a null frame with power save disabled. So we need
 57                  * to send a new nullfunc frame to inform the AP that we
 58                  * are again sleeping.
 59                  */
 60                 ieee80211_send_nullfunc(local, sdata, 1);
 61 }
 62 
 63 /* inform AP that we are awake again, unless power save is enabled */
 64 static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata)
 65 {
 66         struct ieee80211_local *local = sdata->local;
 67 
 68         if (!local->ps_sdata)
 69                 ieee80211_send_nullfunc(local, sdata, 0);
 70         else if (local->offchannel_ps_enabled) {
 71                 /*
 72                  * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
 73                  * will send a nullfunc frame with the powersave bit set
 74                  * even though the AP already knows that we are sleeping.
 75                  * This could be avoided by sending a null frame with power
 76                  * save bit disabled before enabling the power save, but
 77                  * this doesn't gain anything.
 78                  *
 79                  * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
 80                  * to send a nullfunc frame because AP already knows that
 81                  * we are sleeping, let's just enable power save mode in
 82                  * hardware.
 83                  */
 84                 /* TODO:  Only set hardware if CONF_PS changed?
 85                  * TODO:  Should we set offchannel_ps_enabled to false?
 86                  */
 87                 local->hw.conf.flags |= IEEE80211_CONF_PS;
 88                 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
 89         } else if (local->hw.conf.dynamic_ps_timeout > 0) {
 90                 /*
 91                  * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
 92                  * had been running before leaving the operating channel,
 93                  * restart the timer now and send a nullfunc frame to inform
 94                  * the AP that we are awake.
 95                  */
 96                 ieee80211_send_nullfunc(local, sdata, 0);
 97                 mod_timer(&local->dynamic_ps_timer, jiffies +
 98                           msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
 99         }
100 
101         ieee80211_sta_reset_beacon_monitor(sdata);
102         ieee80211_sta_reset_conn_monitor(sdata);
103 }
104 
105 void ieee80211_offchannel_stop_vifs(struct ieee80211_local *local)
106 {
107         struct ieee80211_sub_if_data *sdata;
108 
109         if (WARN_ON(local->use_chanctx))
110                 return;
111 
112         /*
113          * notify the AP about us leaving the channel and stop all
114          * STA interfaces.
115          */
116 
117         /*
118          * Stop queues and transmit all frames queued by the driver
119          * before sending nullfunc to enable powersave at the AP.
120          */
121         ieee80211_stop_queues_by_reason(&local->hw,
122                                         IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL);
123         drv_flush(local, false);
124 
125         mutex_lock(&local->iflist_mtx);
126         list_for_each_entry(sdata, &local->interfaces, list) {
127                 if (!ieee80211_sdata_running(sdata))
128                         continue;
129 
130                 if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
131                         continue;
132 
133                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
134                         set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
135 
136                 /* Check to see if we should disable beaconing. */
137                 if (sdata->vif.bss_conf.enable_beacon) {
138                         set_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
139                                 &sdata->state);
140                         sdata->vif.bss_conf.enable_beacon = false;
141                         ieee80211_bss_info_change_notify(
142                                 sdata, BSS_CHANGED_BEACON_ENABLED);
143                 }
144 
145                 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
146                     sdata->u.mgd.associated)
147                         ieee80211_offchannel_ps_enable(sdata);
148         }
149         mutex_unlock(&local->iflist_mtx);
150 }
151 
152 void ieee80211_offchannel_return(struct ieee80211_local *local)
153 {
154         struct ieee80211_sub_if_data *sdata;
155 
156         if (WARN_ON(local->use_chanctx))
157                 return;
158 
159         mutex_lock(&local->iflist_mtx);
160         list_for_each_entry(sdata, &local->interfaces, list) {
161                 if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
162                         continue;
163 
164                 if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
165                         clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
166 
167                 if (!ieee80211_sdata_running(sdata))
168                         continue;
169 
170                 /* Tell AP we're back */
171                 if (sdata->vif.type == NL80211_IFTYPE_STATION &&
172                     sdata->u.mgd.associated)
173                         ieee80211_offchannel_ps_disable(sdata);
174 
175                 if (test_and_clear_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
176                                        &sdata->state)) {
177                         sdata->vif.bss_conf.enable_beacon = true;
178                         ieee80211_bss_info_change_notify(
179                                 sdata, BSS_CHANGED_BEACON_ENABLED);
180                 }
181         }
182         mutex_unlock(&local->iflist_mtx);
183 
184         ieee80211_wake_queues_by_reason(&local->hw,
185                                         IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL);
186 }
187 
188 void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc)
189 {
190         if (roc->notified)
191                 return;
192 
193         if (roc->mgmt_tx_cookie) {
194                 if (!WARN_ON(!roc->frame)) {
195                         ieee80211_tx_skb_tid_band(roc->sdata, roc->frame, 7,
196                                                   roc->chan->band);
197                         roc->frame = NULL;
198                 }
199         } else {
200                 cfg80211_ready_on_channel(&roc->sdata->wdev, roc->cookie,
201                                           roc->chan, roc->req_duration,
202                                           GFP_KERNEL);
203         }
204 
205         roc->notified = true;
206 }
207 
208 static void ieee80211_hw_roc_start(struct work_struct *work)
209 {
210         struct ieee80211_local *local =
211                 container_of(work, struct ieee80211_local, hw_roc_start);
212         struct ieee80211_roc_work *roc, *dep, *tmp;
213 
214         mutex_lock(&local->mtx);
215 
216         if (list_empty(&local->roc_list))
217                 goto out_unlock;
218 
219         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
220                                list);
221 
222         if (!roc->started)
223                 goto out_unlock;
224 
225         roc->hw_begun = true;
226         roc->hw_start_time = local->hw_roc_start_time;
227 
228         ieee80211_handle_roc_started(roc);
229         list_for_each_entry_safe(dep, tmp, &roc->dependents, list) {
230                 ieee80211_handle_roc_started(dep);
231 
232                 if (dep->duration > roc->duration) {
233                         u32 dur = dep->duration;
234                         dep->duration = dur - roc->duration;
235                         roc->duration = dur;
236                         list_move(&dep->list, &roc->list);
237                 }
238         }
239  out_unlock:
240         mutex_unlock(&local->mtx);
241 }
242 
243 void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
244 {
245         struct ieee80211_local *local = hw_to_local(hw);
246 
247         local->hw_roc_start_time = jiffies;
248 
249         trace_api_ready_on_channel(local);
250 
251         ieee80211_queue_work(hw, &local->hw_roc_start);
252 }
253 EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
254 
255 void ieee80211_start_next_roc(struct ieee80211_local *local)
256 {
257         struct ieee80211_roc_work *roc;
258 
259         lockdep_assert_held(&local->mtx);
260 
261         if (list_empty(&local->roc_list)) {
262                 ieee80211_run_deferred_scan(local);
263                 return;
264         }
265 
266         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
267                                list);
268 
269         if (WARN_ON_ONCE(roc->started))
270                 return;
271 
272         if (local->ops->remain_on_channel) {
273                 int ret, duration = roc->duration;
274 
275                 /* XXX: duplicated, see ieee80211_start_roc_work() */
276                 if (!duration)
277                         duration = 10;
278 
279                 ret = drv_remain_on_channel(local, roc->sdata, roc->chan,
280                                             duration);
281 
282                 roc->started = true;
283 
284                 if (ret) {
285                         wiphy_warn(local->hw.wiphy,
286                                    "failed to start next HW ROC (%d)\n", ret);
287                         /*
288                          * queue the work struct again to avoid recursion
289                          * when multiple failures occur
290                          */
291                         ieee80211_remain_on_channel_expired(&local->hw);
292                 }
293         } else {
294                 /* delay it a bit */
295                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
296                                              round_jiffies_relative(HZ/2));
297         }
298 }
299 
300 void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc, bool free)
301 {
302         struct ieee80211_roc_work *dep, *tmp;
303 
304         if (WARN_ON(roc->to_be_freed))
305                 return;
306 
307         /* was never transmitted */
308         if (roc->frame) {
309                 cfg80211_mgmt_tx_status(&roc->sdata->wdev,
310                                         (unsigned long)roc->frame,
311                                         roc->frame->data, roc->frame->len,
312                                         false, GFP_KERNEL);
313                 kfree_skb(roc->frame);
314         }
315 
316         if (!roc->mgmt_tx_cookie)
317                 cfg80211_remain_on_channel_expired(&roc->sdata->wdev,
318                                                    roc->cookie, roc->chan,
319                                                    GFP_KERNEL);
320 
321         list_for_each_entry_safe(dep, tmp, &roc->dependents, list)
322                 ieee80211_roc_notify_destroy(dep, true);
323 
324         if (free)
325                 kfree(roc);
326         else
327                 roc->to_be_freed = true;
328 }
329 
330 void ieee80211_sw_roc_work(struct work_struct *work)
331 {
332         struct ieee80211_roc_work *roc =
333                 container_of(work, struct ieee80211_roc_work, work.work);
334         struct ieee80211_sub_if_data *sdata = roc->sdata;
335         struct ieee80211_local *local = sdata->local;
336         bool started;
337 
338         mutex_lock(&local->mtx);
339 
340         if (roc->to_be_freed)
341                 goto out_unlock;
342 
343         if (roc->abort)
344                 goto finish;
345 
346         if (WARN_ON(list_empty(&local->roc_list)))
347                 goto out_unlock;
348 
349         if (WARN_ON(roc != list_first_entry(&local->roc_list,
350                                             struct ieee80211_roc_work,
351                                             list)))
352                 goto out_unlock;
353 
354         if (!roc->started) {
355                 struct ieee80211_roc_work *dep;
356 
357                 /* start this ROC */
358 
359                 /* switch channel etc */
360                 ieee80211_recalc_idle(local);
361 
362                 local->tmp_channel = roc->chan;
363                 ieee80211_hw_config(local, 0);
364 
365                 /* tell userspace or send frame */
366                 ieee80211_handle_roc_started(roc);
367                 list_for_each_entry(dep, &roc->dependents, list)
368                         ieee80211_handle_roc_started(dep);
369 
370                 /* if it was pure TX, just finish right away */
371                 if (!roc->duration)
372                         goto finish;
373 
374                 roc->started = true;
375                 ieee80211_queue_delayed_work(&local->hw, &roc->work,
376                                              msecs_to_jiffies(roc->duration));
377         } else {
378                 /* finish this ROC */
379  finish:
380                 list_del(&roc->list);
381                 started = roc->started;
382                 ieee80211_roc_notify_destroy(roc, !roc->abort);
383 
384                 if (started) {
385                         drv_flush(local, false);
386 
387                         local->tmp_channel = NULL;
388                         ieee80211_hw_config(local, 0);
389 
390                         ieee80211_offchannel_return(local);
391                 }
392 
393                 ieee80211_recalc_idle(local);
394 
395                 if (started)
396                         ieee80211_start_next_roc(local);
397         }
398 
399  out_unlock:
400         mutex_unlock(&local->mtx);
401 }
402 
403 static void ieee80211_hw_roc_done(struct work_struct *work)
404 {
405         struct ieee80211_local *local =
406                 container_of(work, struct ieee80211_local, hw_roc_done);
407         struct ieee80211_roc_work *roc;
408 
409         mutex_lock(&local->mtx);
410 
411         if (list_empty(&local->roc_list))
412                 goto out_unlock;
413 
414         roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
415                                list);
416 
417         if (!roc->started)
418                 goto out_unlock;
419 
420         list_del(&roc->list);
421 
422         ieee80211_roc_notify_destroy(roc, true);
423 
424         /* if there's another roc, start it now */
425         ieee80211_start_next_roc(local);
426 
427  out_unlock:
428         mutex_unlock(&local->mtx);
429 }
430 
431 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
432 {
433         struct ieee80211_local *local = hw_to_local(hw);
434 
435         trace_api_remain_on_channel_expired(local);
436 
437         ieee80211_queue_work(hw, &local->hw_roc_done);
438 }
439 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
440 
441 void ieee80211_roc_setup(struct ieee80211_local *local)
442 {
443         INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
444         INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
445         INIT_LIST_HEAD(&local->roc_list);
446 }
447 
448 void ieee80211_roc_purge(struct ieee80211_sub_if_data *sdata)
449 {
450         struct ieee80211_local *local = sdata->local;
451         struct ieee80211_roc_work *roc, *tmp;
452         LIST_HEAD(tmp_list);
453 
454         mutex_lock(&local->mtx);
455         list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
456                 if (roc->sdata != sdata)
457                         continue;
458 
459                 if (roc->started && local->ops->remain_on_channel) {
460                         /* can race, so ignore return value */
461                         drv_cancel_remain_on_channel(local);
462                 }
463 
464                 list_move_tail(&roc->list, &tmp_list);
465                 roc->abort = true;
466         }
467         mutex_unlock(&local->mtx);
468 
469         list_for_each_entry_safe(roc, tmp, &tmp_list, list) {
470                 if (local->ops->remain_on_channel) {
471                         list_del(&roc->list);
472                         ieee80211_roc_notify_destroy(roc, true);
473                 } else {
474                         ieee80211_queue_delayed_work(&local->hw, &roc->work, 0);
475 
476                         /* work will clean up etc */
477                         flush_delayed_work(&roc->work);
478                         WARN_ON(!roc->to_be_freed);
479                         kfree(roc);
480                 }
481         }
482 
483         WARN_ON_ONCE(!list_empty(&tmp_list));
484 }
485 

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