xref: /openbmc/linux/net/mac80211/offchannel.c (revision 9d749629) 
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)
301 {
302 	struct ieee80211_roc_work *dep, *tmp;
303 
304 	/* was never transmitted */
305 	if (roc->frame) {
306 		cfg80211_mgmt_tx_status(&roc->sdata->wdev,
307 					(unsigned long)roc->frame,
308 					roc->frame->data, roc->frame->len,
309 					false, GFP_KERNEL);
310 		kfree_skb(roc->frame);
311 	}
312 
313 	if (!roc->mgmt_tx_cookie)
314 		cfg80211_remain_on_channel_expired(&roc->sdata->wdev,
315 						   roc->cookie, roc->chan,
316 						   GFP_KERNEL);
317 
318 	list_for_each_entry_safe(dep, tmp, &roc->dependents, list)
319 		ieee80211_roc_notify_destroy(dep);
320 
321 	kfree(roc);
322 }
323 
324 void ieee80211_sw_roc_work(struct work_struct *work)
325 {
326 	struct ieee80211_roc_work *roc =
327 		container_of(work, struct ieee80211_roc_work, work.work);
328 	struct ieee80211_sub_if_data *sdata = roc->sdata;
329 	struct ieee80211_local *local = sdata->local;
330 	bool started;
331 
332 	mutex_lock(&local->mtx);
333 
334 	if (roc->abort)
335 		goto finish;
336 
337 	if (WARN_ON(list_empty(&local->roc_list)))
338 		goto out_unlock;
339 
340 	if (WARN_ON(roc != list_first_entry(&local->roc_list,
341 					    struct ieee80211_roc_work,
342 					    list)))
343 		goto out_unlock;
344 
345 	if (!roc->started) {
346 		struct ieee80211_roc_work *dep;
347 
348 		/* start this ROC */
349 
350 		/* switch channel etc */
351 		ieee80211_recalc_idle(local);
352 
353 		local->tmp_channel = roc->chan;
354 		ieee80211_hw_config(local, 0);
355 
356 		/* tell userspace or send frame */
357 		ieee80211_handle_roc_started(roc);
358 		list_for_each_entry(dep, &roc->dependents, list)
359 			ieee80211_handle_roc_started(dep);
360 
361 		/* if it was pure TX, just finish right away */
362 		if (!roc->duration)
363 			goto finish;
364 
365 		roc->started = true;
366 		ieee80211_queue_delayed_work(&local->hw, &roc->work,
367 					     msecs_to_jiffies(roc->duration));
368 	} else {
369 		/* finish this ROC */
370  finish:
371 		list_del(&roc->list);
372 		started = roc->started;
373 		ieee80211_roc_notify_destroy(roc);
374 
375 		if (started) {
376 			drv_flush(local, false);
377 
378 			local->tmp_channel = NULL;
379 			ieee80211_hw_config(local, 0);
380 
381 			ieee80211_offchannel_return(local);
382 		}
383 
384 		ieee80211_recalc_idle(local);
385 
386 		if (started)
387 			ieee80211_start_next_roc(local);
388 	}
389 
390  out_unlock:
391 	mutex_unlock(&local->mtx);
392 }
393 
394 static void ieee80211_hw_roc_done(struct work_struct *work)
395 {
396 	struct ieee80211_local *local =
397 		container_of(work, struct ieee80211_local, hw_roc_done);
398 	struct ieee80211_roc_work *roc;
399 
400 	mutex_lock(&local->mtx);
401 
402 	if (list_empty(&local->roc_list))
403 		goto out_unlock;
404 
405 	roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
406 			       list);
407 
408 	if (!roc->started)
409 		goto out_unlock;
410 
411 	list_del(&roc->list);
412 
413 	ieee80211_roc_notify_destroy(roc);
414 
415 	/* if there's another roc, start it now */
416 	ieee80211_start_next_roc(local);
417 
418  out_unlock:
419 	mutex_unlock(&local->mtx);
420 }
421 
422 void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
423 {
424 	struct ieee80211_local *local = hw_to_local(hw);
425 
426 	trace_api_remain_on_channel_expired(local);
427 
428 	ieee80211_queue_work(hw, &local->hw_roc_done);
429 }
430 EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
431 
432 void ieee80211_roc_setup(struct ieee80211_local *local)
433 {
434 	INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
435 	INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
436 	INIT_LIST_HEAD(&local->roc_list);
437 }
438 
439 void ieee80211_roc_purge(struct ieee80211_sub_if_data *sdata)
440 {
441 	struct ieee80211_local *local = sdata->local;
442 	struct ieee80211_roc_work *roc, *tmp;
443 	LIST_HEAD(tmp_list);
444 
445 	mutex_lock(&local->mtx);
446 	list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
447 		if (roc->sdata != sdata)
448 			continue;
449 
450 		if (roc->started && local->ops->remain_on_channel) {
451 			/* can race, so ignore return value */
452 			drv_cancel_remain_on_channel(local);
453 		}
454 
455 		list_move_tail(&roc->list, &tmp_list);
456 		roc->abort = true;
457 	}
458 	mutex_unlock(&local->mtx);
459 
460 	list_for_each_entry_safe(roc, tmp, &tmp_list, list) {
461 		if (local->ops->remain_on_channel) {
462 			list_del(&roc->list);
463 			ieee80211_roc_notify_destroy(roc);
464 		} else {
465 			ieee80211_queue_delayed_work(&local->hw, &roc->work, 0);
466 
467 			/* work will clean up etc */
468 			flush_delayed_work(&roc->work);
469 		}
470 	}
471 
472 	WARN_ON_ONCE(!list_empty(&tmp_list));
473 }
474