summaryrefslogtreecommitdiffstats
path: root/net/mac80211/work.c
blob: b2650a9d45ff765c7555628f82dea3c673a76380 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
/*
 * mac80211 work implementation
 *
 * Copyright 2003-2008, Jouni Malinen <j@w1.fi>
 * Copyright 2004, Instant802 Networks, Inc.
 * Copyright 2005, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
 * Copyright 2009, Johannes Berg <johannes@sipsolutions.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/delay.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/if_arp.h>
#include <linux/etherdevice.h>
#include <linux/crc32.h>
#include <linux/slab.h>
#include <net/mac80211.h>
#include <asm/unaligned.h>

#include "ieee80211_i.h"
#include "rate.h"
#include "driver-ops.h"

enum work_action {
	WORK_ACT_NONE,
	WORK_ACT_TIMEOUT,
};


/* utils */
static inline void ASSERT_WORK_MTX(struct ieee80211_local *local)
{
	lockdep_assert_held(&local->mtx);
}

/*
 * We can have multiple work items (and connection probing)
 * scheduling this timer, but we need to take care to only
 * reschedule it when it should fire _earlier_ than it was
 * asked for before, or if it's not pending right now. This
 * function ensures that. Note that it then is required to
 * run this function for all timeouts after the first one
 * has happened -- the work that runs from this timer will
 * do that.
 */
static void run_again(struct ieee80211_local *local,
		      unsigned long timeout)
{
	ASSERT_WORK_MTX(local);

	if (!timer_pending(&local->work_timer) ||
	    time_before(timeout, local->work_timer.expires))
		mod_timer(&local->work_timer, timeout);
}

void free_work(struct ieee80211_work *wk)
{
	kfree_rcu(wk, rcu_head);
}

static enum work_action __must_check
ieee80211_remain_on_channel_timeout(struct ieee80211_work *wk)
{
	/*
	 * First time we run, do nothing -- the generic code will
	 * have switched to the right channel etc.
	 */
	if (!wk->started) {
		wk->timeout = jiffies + msecs_to_jiffies(wk->remain.duration);

		cfg80211_ready_on_channel(wk->sdata->dev, (unsigned long) wk,
					  wk->chan, wk->chan_type,
					  wk->remain.duration, GFP_KERNEL);

		return WORK_ACT_NONE;
	}

	return WORK_ACT_TIMEOUT;
}

static enum work_action __must_check
ieee80211_offchannel_tx(struct ieee80211_work *wk)
{
	if (!wk->started) {
		wk->timeout = jiffies + msecs_to_jiffies(wk->offchan_tx.wait);

		/*
		 * After this, offchan_tx.frame remains but now is no
		 * longer a valid pointer -- we still need it as the
		 * cookie for canceling this work/status matching.
		 */
		ieee80211_tx_skb(wk->sdata, wk->offchan_tx.frame);

		return WORK_ACT_NONE;
	}

	return WORK_ACT_TIMEOUT;
}

static void ieee80211_work_timer(unsigned long data)
{
	struct ieee80211_local *local = (void *) data;

	if (local->quiescing)
		return;

	ieee80211_queue_work(&local->hw, &local->work_work);
}

static void ieee80211_work_work(struct work_struct *work)
{
	struct ieee80211_local *local =
		container_of(work, struct ieee80211_local, work_work);
	struct ieee80211_work *wk, *tmp;
	LIST_HEAD(free_work);
	enum work_action rma;
	bool remain_off_channel = false;

	/*
	 * ieee80211_queue_work() should have picked up most cases,
	 * here we'll pick the rest.
	 */
	if (WARN(local->suspended, "work scheduled while going to suspend\n"))
		return;

	mutex_lock(&local->mtx);

	if (local->scanning) {
		mutex_unlock(&local->mtx);
		return;
	}

	ieee80211_recalc_idle(local);

	list_for_each_entry_safe(wk, tmp, &local->work_list, list) {
		bool started = wk->started;

		/* mark work as started if it's on the current off-channel */
		if (!started && local->tmp_channel &&
		    wk->chan == local->tmp_channel &&
		    wk->chan_type == local->tmp_channel_type) {
			started = true;
			wk->timeout = jiffies;
		}

		if (!started && !local->tmp_channel) {
			ieee80211_offchannel_stop_vifs(local, true);

			local->tmp_channel = wk->chan;
			local->tmp_channel_type = wk->chan_type;

			ieee80211_hw_config(local, 0);

			started = true;
			wk->timeout = jiffies;
		}

		/* don't try to work with items that aren't started */
		if (!started)
			continue;

		if (time_is_after_jiffies(wk->timeout)) {
			/*
			 * This work item isn't supposed to be worked on
			 * right now, but take care to adjust the timer
			 * properly.
			 */
			run_again(local, wk->timeout);
			continue;
		}

		switch (wk->type) {
		default:
			WARN_ON(1);
			/* nothing */
			rma = WORK_ACT_NONE;
			break;
		case IEEE80211_WORK_ABORT:
			rma = WORK_ACT_TIMEOUT;
			break;
		case IEEE80211_WORK_REMAIN_ON_CHANNEL:
			rma = ieee80211_remain_on_channel_timeout(wk);
			break;
		case IEEE80211_WORK_OFFCHANNEL_TX:
			rma = ieee80211_offchannel_tx(wk);
			break;
		}

		wk->started = started;

		switch (rma) {
		case WORK_ACT_NONE:
			/* might have changed the timeout */
			run_again(local, wk->timeout);
			break;
		case WORK_ACT_TIMEOUT:
			list_del_rcu(&wk->list);
			synchronize_rcu();
			list_add(&wk->list, &free_work);
			break;
		default:
			WARN(1, "unexpected: %d", rma);
		}
	}

	list_for_each_entry(wk, &local->work_list, list) {
		if (!wk->started)
			continue;
		if (wk->chan != local->tmp_channel ||
		    wk->chan_type != local->tmp_channel_type)
			continue;
		remain_off_channel = true;
	}

	if (!remain_off_channel && local->tmp_channel) {
		local->tmp_channel = NULL;
		ieee80211_hw_config(local, 0);

		ieee80211_offchannel_return(local, true);

		/* give connection some time to breathe */
		run_again(local, jiffies + HZ/2);
	}

	ieee80211_recalc_idle(local);
	ieee80211_run_deferred_scan(local);

	mutex_unlock(&local->mtx);

	list_for_each_entry_safe(wk, tmp, &free_work, list) {
		wk->done(wk, NULL);
		list_del(&wk->list);
		kfree(wk);
	}
}

void ieee80211_add_work(struct ieee80211_work *wk)
{
	struct ieee80211_local *local;

	if (WARN_ON(!wk->chan))
		return;

	if (WARN_ON(!wk->sdata))
		return;

	if (WARN_ON(!wk->done))
		return;

	if (WARN_ON(!ieee80211_sdata_running(wk->sdata)))
		return;

	wk->started = false;

	local = wk->sdata->local;
	mutex_lock(&local->mtx);
	list_add_tail(&wk->list, &local->work_list);
	mutex_unlock(&local->mtx);

	ieee80211_queue_work(&local->hw, &local->work_work);
}

void ieee80211_work_init(struct ieee80211_local *local)
{
	INIT_LIST_HEAD(&local->work_list);
	setup_timer(&local->work_timer, ieee80211_work_timer,
		    (unsigned long)local);
	INIT_WORK(&local->work_work, ieee80211_work_work);
}

void ieee80211_work_purge(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_work *wk;
	bool cleanup = false;

	mutex_lock(&local->mtx);
	list_for_each_entry(wk, &local->work_list, list) {
		if (wk->sdata != sdata)
			continue;
		cleanup = true;
		wk->type = IEEE80211_WORK_ABORT;
		wk->started = true;
		wk->timeout = jiffies;
	}
	mutex_unlock(&local->mtx);

	/* run cleanups etc. */
	if (cleanup)
		ieee80211_work_work(&local->work_work);

	mutex_lock(&local->mtx);
	list_for_each_entry(wk, &local->work_list, list) {
		if (wk->sdata != sdata)
			continue;
		WARN_ON(1);
		break;
	}
	mutex_unlock(&local->mtx);
}

static enum work_done_result ieee80211_remain_done(struct ieee80211_work *wk,
						   struct sk_buff *skb)
{
	/*
	 * We are done serving the remain-on-channel command.
	 */
	cfg80211_remain_on_channel_expired(wk->sdata->dev, (unsigned long) wk,
					   wk->chan, wk->chan_type,
					   GFP_KERNEL);

	return WORK_DONE_DESTROY;
}

int ieee80211_wk_remain_on_channel(struct ieee80211_sub_if_data *sdata,
				   struct ieee80211_channel *chan,
				   enum nl80211_channel_type channel_type,
				   unsigned int duration, u64 *cookie)
{
	struct ieee80211_work *wk;

	wk = kzalloc(sizeof(*wk), GFP_KERNEL);
	if (!wk)
		return -ENOMEM;

	wk->type = IEEE80211_WORK_REMAIN_ON_CHANNEL;
	wk->chan = chan;
	wk->chan_type = channel_type;
	wk->sdata = sdata;
	wk->done = ieee80211_remain_done;

	wk->remain.duration = duration;

	*cookie = (unsigned long) wk;

	ieee80211_add_work(wk);

	return 0;
}

int ieee80211_wk_cancel_remain_on_channel(struct ieee80211_sub_if_data *sdata,
					  u64 cookie)
{
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_work *wk, *tmp;
	bool found = false;

	mutex_lock(&local->mtx);
	list_for_each_entry_safe(wk, tmp, &local->work_list, list) {
		if ((unsigned long) wk == cookie) {
			wk->timeout = jiffies;
			found = true;
			break;
		}
	}
	mutex_unlock(&local->mtx);

	if (!found)
		return -ENOENT;

	ieee80211_queue_work(&local->hw, &local->work_work);

	return 0;
}
OpenPOWER on IntegriCloud