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 */
27static 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 */
64static 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
105void 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, IEEE80211_MAX_QUEUE_MAP,
122					IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL,
123					false);
124	ieee80211_flush_queues(local, NULL, false);
125
126	mutex_lock(&local->iflist_mtx);
127	list_for_each_entry(sdata, &local->interfaces, list) {
128		if (!ieee80211_sdata_running(sdata))
129			continue;
130
131		if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
132			continue;
133
134		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
135			set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
136
137		/* Check to see if we should disable beaconing. */
138		if (sdata->vif.bss_conf.enable_beacon) {
139			set_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
140				&sdata->state);
141			sdata->vif.bss_conf.enable_beacon = false;
142			ieee80211_bss_info_change_notify(
143				sdata, BSS_CHANGED_BEACON_ENABLED);
144		}
145
146		if (sdata->vif.type == NL80211_IFTYPE_STATION &&
147		    sdata->u.mgd.associated)
148			ieee80211_offchannel_ps_enable(sdata);
149	}
150	mutex_unlock(&local->iflist_mtx);
151}
152
153void ieee80211_offchannel_return(struct ieee80211_local *local)
154{
155	struct ieee80211_sub_if_data *sdata;
156
157	if (WARN_ON(local->use_chanctx))
158		return;
159
160	mutex_lock(&local->iflist_mtx);
161	list_for_each_entry(sdata, &local->interfaces, list) {
162		if (sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE)
163			continue;
164
165		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
166			clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
167
168		if (!ieee80211_sdata_running(sdata))
169			continue;
170
171		/* Tell AP we're back */
172		if (sdata->vif.type == NL80211_IFTYPE_STATION &&
173		    sdata->u.mgd.associated)
174			ieee80211_offchannel_ps_disable(sdata);
175
176		if (test_and_clear_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
177				       &sdata->state)) {
178			sdata->vif.bss_conf.enable_beacon = true;
179			ieee80211_bss_info_change_notify(
180				sdata, BSS_CHANGED_BEACON_ENABLED);
181		}
182	}
183	mutex_unlock(&local->iflist_mtx);
184
185	ieee80211_wake_queues_by_reason(&local->hw, IEEE80211_MAX_QUEUE_MAP,
186					IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL,
187					false);
188}
189
190void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc)
191{
192	if (roc->notified)
193		return;
194
195	if (roc->mgmt_tx_cookie) {
196		if (!WARN_ON(!roc->frame)) {
197			ieee80211_tx_skb_tid_band(roc->sdata, roc->frame, 7,
198						  roc->chan->band);
199			roc->frame = NULL;
200		}
201	} else {
202		cfg80211_ready_on_channel(&roc->sdata->wdev, roc->cookie,
203					  roc->chan, roc->req_duration,
204					  GFP_KERNEL);
205	}
206
207	roc->notified = true;
208}
209
210static void ieee80211_hw_roc_start(struct work_struct *work)
211{
212	struct ieee80211_local *local =
213		container_of(work, struct ieee80211_local, hw_roc_start);
214	struct ieee80211_roc_work *roc, *dep, *tmp;
215
216	mutex_lock(&local->mtx);
217
218	if (list_empty(&local->roc_list))
219		goto out_unlock;
220
221	roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
222			       list);
223
224	if (!roc->started)
225		goto out_unlock;
226
227	roc->hw_begun = true;
228	roc->hw_start_time = local->hw_roc_start_time;
229
230	ieee80211_handle_roc_started(roc);
231	list_for_each_entry_safe(dep, tmp, &roc->dependents, list) {
232		ieee80211_handle_roc_started(dep);
233
234		if (dep->duration > roc->duration) {
235			u32 dur = dep->duration;
236			dep->duration = dur - roc->duration;
237			roc->duration = dur;
238			list_move(&dep->list, &roc->list);
239		}
240	}
241 out_unlock:
242	mutex_unlock(&local->mtx);
243}
244
245void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
246{
247	struct ieee80211_local *local = hw_to_local(hw);
248
249	local->hw_roc_start_time = jiffies;
250
251	trace_api_ready_on_channel(local);
252
253	ieee80211_queue_work(hw, &local->hw_roc_start);
254}
255EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
256
257void ieee80211_start_next_roc(struct ieee80211_local *local)
258{
259	struct ieee80211_roc_work *roc;
260
261	lockdep_assert_held(&local->mtx);
262
263	if (list_empty(&local->roc_list)) {
264		ieee80211_run_deferred_scan(local);
265		return;
266	}
267
268	roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
269			       list);
270
271	if (WARN_ON_ONCE(roc->started))
272		return;
273
274	if (local->ops->remain_on_channel) {
275		int ret, duration = roc->duration;
276
277		/* XXX: duplicated, see ieee80211_start_roc_work() */
278		if (!duration)
279			duration = 10;
280
281		ret = drv_remain_on_channel(local, roc->sdata, roc->chan,
282					    duration, roc->type);
283
284		roc->started = true;
285
286		if (ret) {
287			wiphy_warn(local->hw.wiphy,
288				   "failed to start next HW ROC (%d)\n", ret);
289			/*
290			 * queue the work struct again to avoid recursion
291			 * when multiple failures occur
292			 */
293			ieee80211_remain_on_channel_expired(&local->hw);
294		}
295	} else {
296		/* delay it a bit */
297		ieee80211_queue_delayed_work(&local->hw, &roc->work,
298					     round_jiffies_relative(HZ/2));
299	}
300}
301
302void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc, bool free)
303{
304	struct ieee80211_roc_work *dep, *tmp;
305
306	if (WARN_ON(roc->to_be_freed))
307		return;
308
309	/* was never transmitted */
310	if (roc->frame) {
311		cfg80211_mgmt_tx_status(&roc->sdata->wdev,
312					(unsigned long)roc->frame,
313					roc->frame->data, roc->frame->len,
314					false, GFP_KERNEL);
315		kfree_skb(roc->frame);
316	}
317
318	if (!roc->mgmt_tx_cookie)
319		cfg80211_remain_on_channel_expired(&roc->sdata->wdev,
320						   roc->cookie, roc->chan,
321						   GFP_KERNEL);
322
323	list_for_each_entry_safe(dep, tmp, &roc->dependents, list)
324		ieee80211_roc_notify_destroy(dep, true);
325
326	if (free)
327		kfree(roc);
328	else
329		roc->to_be_freed = true;
330}
331
332void ieee80211_sw_roc_work(struct work_struct *work)
333{
334	struct ieee80211_roc_work *roc =
335		container_of(work, struct ieee80211_roc_work, work.work);
336	struct ieee80211_sub_if_data *sdata = roc->sdata;
337	struct ieee80211_local *local = sdata->local;
338	bool started, on_channel;
339
340	mutex_lock(&local->mtx);
341
342	if (roc->to_be_freed)
343		goto out_unlock;
344
345	if (roc->abort)
346		goto finish;
347
348	if (WARN_ON(list_empty(&local->roc_list)))
349		goto out_unlock;
350
351	if (WARN_ON(roc != list_first_entry(&local->roc_list,
352					    struct ieee80211_roc_work,
353					    list)))
354		goto out_unlock;
355
356	if (!roc->started) {
357		struct ieee80211_roc_work *dep;
358
359		WARN_ON(local->use_chanctx);
360
361		/* If actually operating on the desired channel (with at least
362		 * 20 MHz channel width) don't stop all the operations but still
363		 * treat it as though the ROC operation started properly, so
364		 * other ROC operations won't interfere with this one.
365		 */
366		roc->on_channel = roc->chan == local->_oper_chandef.chan &&
367				  local->_oper_chandef.width != NL80211_CHAN_WIDTH_5 &&
368				  local->_oper_chandef.width != NL80211_CHAN_WIDTH_10;
369
370		/* start this ROC */
371		ieee80211_recalc_idle(local);
372
373		if (!roc->on_channel) {
374			ieee80211_offchannel_stop_vifs(local);
375
376			local->tmp_channel = roc->chan;
377			ieee80211_hw_config(local, 0);
378		}
379
380		/* tell userspace or send frame */
381		ieee80211_handle_roc_started(roc);
382		list_for_each_entry(dep, &roc->dependents, list)
383			ieee80211_handle_roc_started(dep);
384
385		/* if it was pure TX, just finish right away */
386		if (!roc->duration)
387			goto finish;
388
389		roc->started = true;
390		ieee80211_queue_delayed_work(&local->hw, &roc->work,
391					     msecs_to_jiffies(roc->duration));
392	} else {
393		/* finish this ROC */
394 finish:
395		list_del(&roc->list);
396		started = roc->started;
397		on_channel = roc->on_channel;
398		ieee80211_roc_notify_destroy(roc, !roc->abort);
399
400		if (started && !on_channel) {
401			ieee80211_flush_queues(local, NULL, false);
402
403			local->tmp_channel = NULL;
404			ieee80211_hw_config(local, 0);
405
406			ieee80211_offchannel_return(local);
407		}
408
409		ieee80211_recalc_idle(local);
410
411		if (started)
412			ieee80211_start_next_roc(local);
413		else if (list_empty(&local->roc_list))
414			ieee80211_run_deferred_scan(local);
415	}
416
417 out_unlock:
418	mutex_unlock(&local->mtx);
419}
420
421static void ieee80211_hw_roc_done(struct work_struct *work)
422{
423	struct ieee80211_local *local =
424		container_of(work, struct ieee80211_local, hw_roc_done);
425	struct ieee80211_roc_work *roc;
426
427	mutex_lock(&local->mtx);
428
429	if (list_empty(&local->roc_list))
430		goto out_unlock;
431
432	roc = list_first_entry(&local->roc_list, struct ieee80211_roc_work,
433			       list);
434
435	if (!roc->started)
436		goto out_unlock;
437
438	list_del(&roc->list);
439
440	ieee80211_roc_notify_destroy(roc, true);
441
442	/* if there's another roc, start it now */
443	ieee80211_start_next_roc(local);
444
445 out_unlock:
446	mutex_unlock(&local->mtx);
447}
448
449void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
450{
451	struct ieee80211_local *local = hw_to_local(hw);
452
453	trace_api_remain_on_channel_expired(local);
454
455	ieee80211_queue_work(hw, &local->hw_roc_done);
456}
457EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
458
459void ieee80211_roc_setup(struct ieee80211_local *local)
460{
461	INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
462	INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
463	INIT_LIST_HEAD(&local->roc_list);
464}
465
466void ieee80211_roc_purge(struct ieee80211_local *local,
467			 struct ieee80211_sub_if_data *sdata)
468{
469	struct ieee80211_roc_work *roc, *tmp;
470	LIST_HEAD(tmp_list);
471
472	mutex_lock(&local->mtx);
473	list_for_each_entry_safe(roc, tmp, &local->roc_list, list) {
474		if (sdata && roc->sdata != sdata)
475			continue;
476
477		if (roc->started && local->ops->remain_on_channel) {
478			/* can race, so ignore return value */
479			drv_cancel_remain_on_channel(local);
480		}
481
482		list_move_tail(&roc->list, &tmp_list);
483		roc->abort = true;
484	}
485	mutex_unlock(&local->mtx);
486
487	list_for_each_entry_safe(roc, tmp, &tmp_list, list) {
488		if (local->ops->remain_on_channel) {
489			list_del(&roc->list);
490			ieee80211_roc_notify_destroy(roc, true);
491		} else {
492			ieee80211_queue_delayed_work(&local->hw, &roc->work, 0);
493
494			/* work will clean up etc */
495			flush_delayed_work(&roc->work);
496			WARN_ON(!roc->to_be_freed);
497			kfree(roc);
498		}
499	}
500
501	WARN_ON_ONCE(!list_empty(&tmp_list));
502}
503