xref: /openbmc/linux/net/mac80211/rate.c (revision 22d55f02)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2002-2005, Instant802 Networks, Inc.
4  * Copyright 2005-2006, Devicescape Software, Inc.
5  * Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
6  * Copyright 2017	Intel Deutschland GmbH
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/rtnetlink.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include "rate.h"
14 #include "ieee80211_i.h"
15 #include "debugfs.h"
16 
17 struct rate_control_alg {
18 	struct list_head list;
19 	const struct rate_control_ops *ops;
20 };
21 
22 static LIST_HEAD(rate_ctrl_algs);
23 static DEFINE_MUTEX(rate_ctrl_mutex);
24 
25 static char *ieee80211_default_rc_algo = CONFIG_MAC80211_RC_DEFAULT;
26 module_param(ieee80211_default_rc_algo, charp, 0644);
27 MODULE_PARM_DESC(ieee80211_default_rc_algo,
28 		 "Default rate control algorithm for mac80211 to use");
29 
30 void rate_control_rate_init(struct sta_info *sta)
31 {
32 	struct ieee80211_local *local = sta->sdata->local;
33 	struct rate_control_ref *ref = sta->rate_ctrl;
34 	struct ieee80211_sta *ista = &sta->sta;
35 	void *priv_sta = sta->rate_ctrl_priv;
36 	struct ieee80211_supported_band *sband;
37 	struct ieee80211_chanctx_conf *chanctx_conf;
38 
39 	ieee80211_sta_set_rx_nss(sta);
40 
41 	if (!ref)
42 		return;
43 
44 	rcu_read_lock();
45 
46 	chanctx_conf = rcu_dereference(sta->sdata->vif.chanctx_conf);
47 	if (WARN_ON(!chanctx_conf)) {
48 		rcu_read_unlock();
49 		return;
50 	}
51 
52 	sband = local->hw.wiphy->bands[chanctx_conf->def.chan->band];
53 
54 	spin_lock_bh(&sta->rate_ctrl_lock);
55 	ref->ops->rate_init(ref->priv, sband, &chanctx_conf->def, ista,
56 			    priv_sta);
57 	spin_unlock_bh(&sta->rate_ctrl_lock);
58 	rcu_read_unlock();
59 	set_sta_flag(sta, WLAN_STA_RATE_CONTROL);
60 }
61 
62 void rate_control_tx_status(struct ieee80211_local *local,
63 			    struct ieee80211_supported_band *sband,
64 			    struct ieee80211_tx_status *st)
65 {
66 	struct rate_control_ref *ref = local->rate_ctrl;
67 	struct sta_info *sta = container_of(st->sta, struct sta_info, sta);
68 	void *priv_sta = sta->rate_ctrl_priv;
69 
70 	if (!ref || !test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
71 		return;
72 
73 	spin_lock_bh(&sta->rate_ctrl_lock);
74 	if (ref->ops->tx_status_ext)
75 		ref->ops->tx_status_ext(ref->priv, sband, priv_sta, st);
76 	else if (st->skb)
77 		ref->ops->tx_status(ref->priv, sband, st->sta, priv_sta, st->skb);
78 	else
79 		WARN_ON_ONCE(1);
80 
81 	spin_unlock_bh(&sta->rate_ctrl_lock);
82 }
83 
84 void rate_control_rate_update(struct ieee80211_local *local,
85 				    struct ieee80211_supported_band *sband,
86 				    struct sta_info *sta, u32 changed)
87 {
88 	struct rate_control_ref *ref = local->rate_ctrl;
89 	struct ieee80211_sta *ista = &sta->sta;
90 	void *priv_sta = sta->rate_ctrl_priv;
91 	struct ieee80211_chanctx_conf *chanctx_conf;
92 
93 	if (ref && ref->ops->rate_update) {
94 		rcu_read_lock();
95 
96 		chanctx_conf = rcu_dereference(sta->sdata->vif.chanctx_conf);
97 		if (WARN_ON(!chanctx_conf)) {
98 			rcu_read_unlock();
99 			return;
100 		}
101 
102 		spin_lock_bh(&sta->rate_ctrl_lock);
103 		ref->ops->rate_update(ref->priv, sband, &chanctx_conf->def,
104 				      ista, priv_sta, changed);
105 		spin_unlock_bh(&sta->rate_ctrl_lock);
106 		rcu_read_unlock();
107 	}
108 	drv_sta_rc_update(local, sta->sdata, &sta->sta, changed);
109 }
110 
111 int ieee80211_rate_control_register(const struct rate_control_ops *ops)
112 {
113 	struct rate_control_alg *alg;
114 
115 	if (!ops->name)
116 		return -EINVAL;
117 
118 	mutex_lock(&rate_ctrl_mutex);
119 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
120 		if (!strcmp(alg->ops->name, ops->name)) {
121 			/* don't register an algorithm twice */
122 			WARN_ON(1);
123 			mutex_unlock(&rate_ctrl_mutex);
124 			return -EALREADY;
125 		}
126 	}
127 
128 	alg = kzalloc(sizeof(*alg), GFP_KERNEL);
129 	if (alg == NULL) {
130 		mutex_unlock(&rate_ctrl_mutex);
131 		return -ENOMEM;
132 	}
133 	alg->ops = ops;
134 
135 	list_add_tail(&alg->list, &rate_ctrl_algs);
136 	mutex_unlock(&rate_ctrl_mutex);
137 
138 	return 0;
139 }
140 EXPORT_SYMBOL(ieee80211_rate_control_register);
141 
142 void ieee80211_rate_control_unregister(const struct rate_control_ops *ops)
143 {
144 	struct rate_control_alg *alg;
145 
146 	mutex_lock(&rate_ctrl_mutex);
147 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
148 		if (alg->ops == ops) {
149 			list_del(&alg->list);
150 			kfree(alg);
151 			break;
152 		}
153 	}
154 	mutex_unlock(&rate_ctrl_mutex);
155 }
156 EXPORT_SYMBOL(ieee80211_rate_control_unregister);
157 
158 static const struct rate_control_ops *
159 ieee80211_try_rate_control_ops_get(const char *name)
160 {
161 	struct rate_control_alg *alg;
162 	const struct rate_control_ops *ops = NULL;
163 
164 	if (!name)
165 		return NULL;
166 
167 	mutex_lock(&rate_ctrl_mutex);
168 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
169 		if (!strcmp(alg->ops->name, name)) {
170 			ops = alg->ops;
171 			break;
172 		}
173 	}
174 	mutex_unlock(&rate_ctrl_mutex);
175 	return ops;
176 }
177 
178 /* Get the rate control algorithm. */
179 static const struct rate_control_ops *
180 ieee80211_rate_control_ops_get(const char *name)
181 {
182 	const struct rate_control_ops *ops;
183 	const char *alg_name;
184 
185 	kernel_param_lock(THIS_MODULE);
186 	if (!name)
187 		alg_name = ieee80211_default_rc_algo;
188 	else
189 		alg_name = name;
190 
191 	ops = ieee80211_try_rate_control_ops_get(alg_name);
192 	if (!ops && name)
193 		/* try default if specific alg requested but not found */
194 		ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);
195 
196 	/* Note: check for > 0 is intentional to avoid clang warning */
197 	if (!ops && (strlen(CONFIG_MAC80211_RC_DEFAULT) > 0))
198 		/* try built-in one if specific alg requested but not found */
199 		ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
200 
201 	kernel_param_unlock(THIS_MODULE);
202 
203 	return ops;
204 }
205 
206 #ifdef CONFIG_MAC80211_DEBUGFS
207 static ssize_t rcname_read(struct file *file, char __user *userbuf,
208 			   size_t count, loff_t *ppos)
209 {
210 	struct rate_control_ref *ref = file->private_data;
211 	int len = strlen(ref->ops->name);
212 
213 	return simple_read_from_buffer(userbuf, count, ppos,
214 				       ref->ops->name, len);
215 }
216 
217 static const struct file_operations rcname_ops = {
218 	.read = rcname_read,
219 	.open = simple_open,
220 	.llseek = default_llseek,
221 };
222 #endif
223 
224 static struct rate_control_ref *rate_control_alloc(const char *name,
225 					    struct ieee80211_local *local)
226 {
227 	struct dentry *debugfsdir = NULL;
228 	struct rate_control_ref *ref;
229 
230 	ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
231 	if (!ref)
232 		return NULL;
233 	ref->ops = ieee80211_rate_control_ops_get(name);
234 	if (!ref->ops)
235 		goto free;
236 
237 #ifdef CONFIG_MAC80211_DEBUGFS
238 	debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir);
239 	local->debugfs.rcdir = debugfsdir;
240 	debugfs_create_file("name", 0400, debugfsdir, ref, &rcname_ops);
241 #endif
242 
243 	ref->priv = ref->ops->alloc(&local->hw, debugfsdir);
244 	if (!ref->priv)
245 		goto free;
246 	return ref;
247 
248 free:
249 	kfree(ref);
250 	return NULL;
251 }
252 
253 static void rate_control_free(struct ieee80211_local *local,
254 			      struct rate_control_ref *ctrl_ref)
255 {
256 	ctrl_ref->ops->free(ctrl_ref->priv);
257 
258 #ifdef CONFIG_MAC80211_DEBUGFS
259 	debugfs_remove_recursive(local->debugfs.rcdir);
260 	local->debugfs.rcdir = NULL;
261 #endif
262 
263 	kfree(ctrl_ref);
264 }
265 
266 void ieee80211_check_rate_mask(struct ieee80211_sub_if_data *sdata)
267 {
268 	struct ieee80211_local *local = sdata->local;
269 	struct ieee80211_supported_band *sband;
270 	u32 user_mask, basic_rates = sdata->vif.bss_conf.basic_rates;
271 	enum nl80211_band band;
272 
273 	if (WARN_ON(!sdata->vif.bss_conf.chandef.chan))
274 		return;
275 
276 	if (WARN_ON_ONCE(!basic_rates))
277 		return;
278 
279 	band = sdata->vif.bss_conf.chandef.chan->band;
280 	user_mask = sdata->rc_rateidx_mask[band];
281 	sband = local->hw.wiphy->bands[band];
282 
283 	if (user_mask & basic_rates)
284 		return;
285 
286 	sdata_dbg(sdata,
287 		  "no overlap between basic rates (0x%x) and user mask (0x%x on band %d) - clearing the latter",
288 		  basic_rates, user_mask, band);
289 	sdata->rc_rateidx_mask[band] = (1 << sband->n_bitrates) - 1;
290 }
291 
292 static bool rc_no_data_or_no_ack_use_min(struct ieee80211_tx_rate_control *txrc)
293 {
294 	struct sk_buff *skb = txrc->skb;
295 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
296 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
297 	__le16 fc;
298 
299 	fc = hdr->frame_control;
300 
301 	return (info->flags & (IEEE80211_TX_CTL_NO_ACK |
302 			       IEEE80211_TX_CTL_USE_MINRATE)) ||
303 		!ieee80211_is_data(fc);
304 }
305 
306 static void rc_send_low_basicrate(s8 *idx, u32 basic_rates,
307 				  struct ieee80211_supported_band *sband)
308 {
309 	u8 i;
310 
311 	if (basic_rates == 0)
312 		return; /* assume basic rates unknown and accept rate */
313 	if (*idx < 0)
314 		return;
315 	if (basic_rates & (1 << *idx))
316 		return; /* selected rate is a basic rate */
317 
318 	for (i = *idx + 1; i <= sband->n_bitrates; i++) {
319 		if (basic_rates & (1 << i)) {
320 			*idx = i;
321 			return;
322 		}
323 	}
324 
325 	/* could not find a basic rate; use original selection */
326 }
327 
328 static void __rate_control_send_low(struct ieee80211_hw *hw,
329 				    struct ieee80211_supported_band *sband,
330 				    struct ieee80211_sta *sta,
331 				    struct ieee80211_tx_info *info,
332 				    u32 rate_mask)
333 {
334 	int i;
335 	u32 rate_flags =
336 		ieee80211_chandef_rate_flags(&hw->conf.chandef);
337 
338 	if ((sband->band == NL80211_BAND_2GHZ) &&
339 	    (info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
340 		rate_flags |= IEEE80211_RATE_ERP_G;
341 
342 	info->control.rates[0].idx = 0;
343 	for (i = 0; i < sband->n_bitrates; i++) {
344 		if (!(rate_mask & BIT(i)))
345 			continue;
346 
347 		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
348 			continue;
349 
350 		if (!rate_supported(sta, sband->band, i))
351 			continue;
352 
353 		info->control.rates[0].idx = i;
354 		break;
355 	}
356 	WARN_ONCE(i == sband->n_bitrates,
357 		  "no supported rates (0x%x) in rate_mask 0x%x with flags 0x%x\n",
358 		  sta ? sta->supp_rates[sband->band] : -1,
359 		  rate_mask, rate_flags);
360 
361 	info->control.rates[0].count =
362 		(info->flags & IEEE80211_TX_CTL_NO_ACK) ?
363 		1 : hw->max_rate_tries;
364 
365 	info->control.skip_table = 1;
366 }
367 
368 
369 bool rate_control_send_low(struct ieee80211_sta *pubsta,
370 			   void *priv_sta,
371 			   struct ieee80211_tx_rate_control *txrc)
372 {
373 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
374 	struct ieee80211_supported_band *sband = txrc->sband;
375 	struct sta_info *sta;
376 	int mcast_rate;
377 	bool use_basicrate = false;
378 
379 	if (!pubsta || !priv_sta || rc_no_data_or_no_ack_use_min(txrc)) {
380 		__rate_control_send_low(txrc->hw, sband, pubsta, info,
381 					txrc->rate_idx_mask);
382 
383 		if (!pubsta && txrc->bss) {
384 			mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
385 			if (mcast_rate > 0) {
386 				info->control.rates[0].idx = mcast_rate - 1;
387 				return true;
388 			}
389 			use_basicrate = true;
390 		} else if (pubsta) {
391 			sta = container_of(pubsta, struct sta_info, sta);
392 			if (ieee80211_vif_is_mesh(&sta->sdata->vif))
393 				use_basicrate = true;
394 		}
395 
396 		if (use_basicrate)
397 			rc_send_low_basicrate(&info->control.rates[0].idx,
398 					      txrc->bss_conf->basic_rates,
399 					      sband);
400 
401 		return true;
402 	}
403 	return false;
404 }
405 EXPORT_SYMBOL(rate_control_send_low);
406 
407 static bool rate_idx_match_legacy_mask(s8 *rate_idx, int n_bitrates, u32 mask)
408 {
409 	int j;
410 
411 	/* See whether the selected rate or anything below it is allowed. */
412 	for (j = *rate_idx; j >= 0; j--) {
413 		if (mask & (1 << j)) {
414 			/* Okay, found a suitable rate. Use it. */
415 			*rate_idx = j;
416 			return true;
417 		}
418 	}
419 
420 	/* Try to find a higher rate that would be allowed */
421 	for (j = *rate_idx + 1; j < n_bitrates; j++) {
422 		if (mask & (1 << j)) {
423 			/* Okay, found a suitable rate. Use it. */
424 			*rate_idx = j;
425 			return true;
426 		}
427 	}
428 	return false;
429 }
430 
431 static bool rate_idx_match_mcs_mask(s8 *rate_idx, u8 *mcs_mask)
432 {
433 	int i, j;
434 	int ridx, rbit;
435 
436 	ridx = *rate_idx / 8;
437 	rbit = *rate_idx % 8;
438 
439 	/* sanity check */
440 	if (ridx < 0 || ridx >= IEEE80211_HT_MCS_MASK_LEN)
441 		return false;
442 
443 	/* See whether the selected rate or anything below it is allowed. */
444 	for (i = ridx; i >= 0; i--) {
445 		for (j = rbit; j >= 0; j--)
446 			if (mcs_mask[i] & BIT(j)) {
447 				*rate_idx = i * 8 + j;
448 				return true;
449 			}
450 		rbit = 7;
451 	}
452 
453 	/* Try to find a higher rate that would be allowed */
454 	ridx = (*rate_idx + 1) / 8;
455 	rbit = (*rate_idx + 1) % 8;
456 
457 	for (i = ridx; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
458 		for (j = rbit; j < 8; j++)
459 			if (mcs_mask[i] & BIT(j)) {
460 				*rate_idx = i * 8 + j;
461 				return true;
462 			}
463 		rbit = 0;
464 	}
465 	return false;
466 }
467 
468 static bool rate_idx_match_vht_mcs_mask(s8 *rate_idx, u16 *vht_mask)
469 {
470 	int i, j;
471 	int ridx, rbit;
472 
473 	ridx = *rate_idx >> 4;
474 	rbit = *rate_idx & 0xf;
475 
476 	if (ridx < 0 || ridx >= NL80211_VHT_NSS_MAX)
477 		return false;
478 
479 	/* See whether the selected rate or anything below it is allowed. */
480 	for (i = ridx; i >= 0; i--) {
481 		for (j = rbit; j >= 0; j--) {
482 			if (vht_mask[i] & BIT(j)) {
483 				*rate_idx = (i << 4) | j;
484 				return true;
485 			}
486 		}
487 		rbit = 15;
488 	}
489 
490 	/* Try to find a higher rate that would be allowed */
491 	ridx = (*rate_idx + 1) >> 4;
492 	rbit = (*rate_idx + 1) & 0xf;
493 
494 	for (i = ridx; i < NL80211_VHT_NSS_MAX; i++) {
495 		for (j = rbit; j < 16; j++) {
496 			if (vht_mask[i] & BIT(j)) {
497 				*rate_idx = (i << 4) | j;
498 				return true;
499 			}
500 		}
501 		rbit = 0;
502 	}
503 	return false;
504 }
505 
506 static void rate_idx_match_mask(s8 *rate_idx, u16 *rate_flags,
507 				struct ieee80211_supported_band *sband,
508 				enum nl80211_chan_width chan_width,
509 				u32 mask,
510 				u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN],
511 				u16 vht_mask[NL80211_VHT_NSS_MAX])
512 {
513 	if (*rate_flags & IEEE80211_TX_RC_VHT_MCS) {
514 		/* handle VHT rates */
515 		if (rate_idx_match_vht_mcs_mask(rate_idx, vht_mask))
516 			return;
517 
518 		*rate_idx = 0;
519 		/* keep protection flags */
520 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
521 				IEEE80211_TX_RC_USE_CTS_PROTECT |
522 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
523 
524 		*rate_flags |= IEEE80211_TX_RC_MCS;
525 		if (chan_width == NL80211_CHAN_WIDTH_40)
526 			*rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
527 
528 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
529 			return;
530 
531 		/* also try the legacy rates. */
532 		*rate_flags &= ~(IEEE80211_TX_RC_MCS |
533 				 IEEE80211_TX_RC_40_MHZ_WIDTH);
534 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
535 					       mask))
536 			return;
537 	} else if (*rate_flags & IEEE80211_TX_RC_MCS) {
538 		/* handle HT rates */
539 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
540 			return;
541 
542 		/* also try the legacy rates. */
543 		*rate_idx = 0;
544 		/* keep protection flags */
545 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
546 				IEEE80211_TX_RC_USE_CTS_PROTECT |
547 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
548 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
549 					       mask))
550 			return;
551 	} else {
552 		/* handle legacy rates */
553 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
554 					       mask))
555 			return;
556 
557 		/* if HT BSS, and we handle a data frame, also try HT rates */
558 		switch (chan_width) {
559 		case NL80211_CHAN_WIDTH_20_NOHT:
560 		case NL80211_CHAN_WIDTH_5:
561 		case NL80211_CHAN_WIDTH_10:
562 			return;
563 		default:
564 			break;
565 		}
566 
567 		*rate_idx = 0;
568 		/* keep protection flags */
569 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
570 				IEEE80211_TX_RC_USE_CTS_PROTECT |
571 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
572 
573 		*rate_flags |= IEEE80211_TX_RC_MCS;
574 
575 		if (chan_width == NL80211_CHAN_WIDTH_40)
576 			*rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
577 
578 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
579 			return;
580 	}
581 
582 	/*
583 	 * Uh.. No suitable rate exists. This should not really happen with
584 	 * sane TX rate mask configurations. However, should someone manage to
585 	 * configure supported rates and TX rate mask in incompatible way,
586 	 * allow the frame to be transmitted with whatever the rate control
587 	 * selected.
588 	 */
589 }
590 
591 static void rate_fixup_ratelist(struct ieee80211_vif *vif,
592 				struct ieee80211_supported_band *sband,
593 				struct ieee80211_tx_info *info,
594 				struct ieee80211_tx_rate *rates,
595 				int max_rates)
596 {
597 	struct ieee80211_rate *rate;
598 	bool inval = false;
599 	int i;
600 
601 	/*
602 	 * Set up the RTS/CTS rate as the fastest basic rate
603 	 * that is not faster than the data rate unless there
604 	 * is no basic rate slower than the data rate, in which
605 	 * case we pick the slowest basic rate
606 	 *
607 	 * XXX: Should this check all retry rates?
608 	 */
609 	if (!(rates[0].flags &
610 	      (IEEE80211_TX_RC_MCS | IEEE80211_TX_RC_VHT_MCS))) {
611 		u32 basic_rates = vif->bss_conf.basic_rates;
612 		s8 baserate = basic_rates ? ffs(basic_rates) - 1 : 0;
613 
614 		rate = &sband->bitrates[rates[0].idx];
615 
616 		for (i = 0; i < sband->n_bitrates; i++) {
617 			/* must be a basic rate */
618 			if (!(basic_rates & BIT(i)))
619 				continue;
620 			/* must not be faster than the data rate */
621 			if (sband->bitrates[i].bitrate > rate->bitrate)
622 				continue;
623 			/* maximum */
624 			if (sband->bitrates[baserate].bitrate <
625 			     sband->bitrates[i].bitrate)
626 				baserate = i;
627 		}
628 
629 		info->control.rts_cts_rate_idx = baserate;
630 	}
631 
632 	for (i = 0; i < max_rates; i++) {
633 		/*
634 		 * make sure there's no valid rate following
635 		 * an invalid one, just in case drivers don't
636 		 * take the API seriously to stop at -1.
637 		 */
638 		if (inval) {
639 			rates[i].idx = -1;
640 			continue;
641 		}
642 		if (rates[i].idx < 0) {
643 			inval = true;
644 			continue;
645 		}
646 
647 		/*
648 		 * For now assume MCS is already set up correctly, this
649 		 * needs to be fixed.
650 		 */
651 		if (rates[i].flags & IEEE80211_TX_RC_MCS) {
652 			WARN_ON(rates[i].idx > 76);
653 
654 			if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
655 			    info->control.use_cts_prot)
656 				rates[i].flags |=
657 					IEEE80211_TX_RC_USE_CTS_PROTECT;
658 			continue;
659 		}
660 
661 		if (rates[i].flags & IEEE80211_TX_RC_VHT_MCS) {
662 			WARN_ON(ieee80211_rate_get_vht_mcs(&rates[i]) > 9);
663 			continue;
664 		}
665 
666 		/* set up RTS protection if desired */
667 		if (info->control.use_rts) {
668 			rates[i].flags |= IEEE80211_TX_RC_USE_RTS_CTS;
669 			info->control.use_cts_prot = false;
670 		}
671 
672 		/* RC is busted */
673 		if (WARN_ON_ONCE(rates[i].idx >= sband->n_bitrates)) {
674 			rates[i].idx = -1;
675 			continue;
676 		}
677 
678 		rate = &sband->bitrates[rates[i].idx];
679 
680 		/* set up short preamble */
681 		if (info->control.short_preamble &&
682 		    rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
683 			rates[i].flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
684 
685 		/* set up G protection */
686 		if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
687 		    info->control.use_cts_prot &&
688 		    rate->flags & IEEE80211_RATE_ERP_G)
689 			rates[i].flags |= IEEE80211_TX_RC_USE_CTS_PROTECT;
690 	}
691 }
692 
693 
694 static void rate_control_fill_sta_table(struct ieee80211_sta *sta,
695 					struct ieee80211_tx_info *info,
696 					struct ieee80211_tx_rate *rates,
697 					int max_rates)
698 {
699 	struct ieee80211_sta_rates *ratetbl = NULL;
700 	int i;
701 
702 	if (sta && !info->control.skip_table)
703 		ratetbl = rcu_dereference(sta->rates);
704 
705 	/* Fill remaining rate slots with data from the sta rate table. */
706 	max_rates = min_t(int, max_rates, IEEE80211_TX_RATE_TABLE_SIZE);
707 	for (i = 0; i < max_rates; i++) {
708 		if (i < ARRAY_SIZE(info->control.rates) &&
709 		    info->control.rates[i].idx >= 0 &&
710 		    info->control.rates[i].count) {
711 			if (rates != info->control.rates)
712 				rates[i] = info->control.rates[i];
713 		} else if (ratetbl) {
714 			rates[i].idx = ratetbl->rate[i].idx;
715 			rates[i].flags = ratetbl->rate[i].flags;
716 			if (info->control.use_rts)
717 				rates[i].count = ratetbl->rate[i].count_rts;
718 			else if (info->control.use_cts_prot)
719 				rates[i].count = ratetbl->rate[i].count_cts;
720 			else
721 				rates[i].count = ratetbl->rate[i].count;
722 		} else {
723 			rates[i].idx = -1;
724 			rates[i].count = 0;
725 		}
726 
727 		if (rates[i].idx < 0 || !rates[i].count)
728 			break;
729 	}
730 }
731 
732 static bool rate_control_cap_mask(struct ieee80211_sub_if_data *sdata,
733 				  struct ieee80211_supported_band *sband,
734 				  struct ieee80211_sta *sta, u32 *mask,
735 				  u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN],
736 				  u16 vht_mask[NL80211_VHT_NSS_MAX])
737 {
738 	u32 i, flags;
739 
740 	*mask = sdata->rc_rateidx_mask[sband->band];
741 	flags = ieee80211_chandef_rate_flags(&sdata->vif.bss_conf.chandef);
742 	for (i = 0; i < sband->n_bitrates; i++) {
743 		if ((flags & sband->bitrates[i].flags) != flags)
744 			*mask &= ~BIT(i);
745 	}
746 
747 	if (*mask == (1 << sband->n_bitrates) - 1 &&
748 	    !sdata->rc_has_mcs_mask[sband->band] &&
749 	    !sdata->rc_has_vht_mcs_mask[sband->band])
750 		return false;
751 
752 	if (sdata->rc_has_mcs_mask[sband->band])
753 		memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[sband->band],
754 		       IEEE80211_HT_MCS_MASK_LEN);
755 	else
756 		memset(mcs_mask, 0xff, IEEE80211_HT_MCS_MASK_LEN);
757 
758 	if (sdata->rc_has_vht_mcs_mask[sband->band])
759 		memcpy(vht_mask, sdata->rc_rateidx_vht_mcs_mask[sband->band],
760 		       sizeof(u16) * NL80211_VHT_NSS_MAX);
761 	else
762 		memset(vht_mask, 0xff, sizeof(u16) * NL80211_VHT_NSS_MAX);
763 
764 	if (sta) {
765 		__le16 sta_vht_cap;
766 		u16 sta_vht_mask[NL80211_VHT_NSS_MAX];
767 
768 		/* Filter out rates that the STA does not support */
769 		*mask &= sta->supp_rates[sband->band];
770 		for (i = 0; i < IEEE80211_HT_MCS_MASK_LEN; i++)
771 			mcs_mask[i] &= sta->ht_cap.mcs.rx_mask[i];
772 
773 		sta_vht_cap = sta->vht_cap.vht_mcs.rx_mcs_map;
774 		ieee80211_get_vht_mask_from_cap(sta_vht_cap, sta_vht_mask);
775 		for (i = 0; i < NL80211_VHT_NSS_MAX; i++)
776 			vht_mask[i] &= sta_vht_mask[i];
777 	}
778 
779 	return true;
780 }
781 
782 static void
783 rate_control_apply_mask_ratetbl(struct sta_info *sta,
784 				struct ieee80211_supported_band *sband,
785 				struct ieee80211_sta_rates *rates)
786 {
787 	int i;
788 	u32 mask;
789 	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
790 	u16 vht_mask[NL80211_VHT_NSS_MAX];
791 	enum nl80211_chan_width chan_width;
792 
793 	if (!rate_control_cap_mask(sta->sdata, sband, &sta->sta, &mask,
794 				   mcs_mask, vht_mask))
795 		return;
796 
797 	chan_width = sta->sdata->vif.bss_conf.chandef.width;
798 	for (i = 0; i < IEEE80211_TX_RATE_TABLE_SIZE; i++) {
799 		if (rates->rate[i].idx < 0)
800 			break;
801 
802 		rate_idx_match_mask(&rates->rate[i].idx, &rates->rate[i].flags,
803 				    sband, chan_width, mask, mcs_mask,
804 				    vht_mask);
805 	}
806 }
807 
808 static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
809 				    struct ieee80211_sta *sta,
810 				    struct ieee80211_supported_band *sband,
811 				    struct ieee80211_tx_rate *rates,
812 				    int max_rates)
813 {
814 	enum nl80211_chan_width chan_width;
815 	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
816 	u32 mask;
817 	u16 rate_flags, vht_mask[NL80211_VHT_NSS_MAX];
818 	int i;
819 
820 	/*
821 	 * Try to enforce the rateidx mask the user wanted. skip this if the
822 	 * default mask (allow all rates) is used to save some processing for
823 	 * the common case.
824 	 */
825 	if (!rate_control_cap_mask(sdata, sband, sta, &mask, mcs_mask,
826 				   vht_mask))
827 		return;
828 
829 	/*
830 	 * Make sure the rate index selected for each TX rate is
831 	 * included in the configured mask and change the rate indexes
832 	 * if needed.
833 	 */
834 	chan_width = sdata->vif.bss_conf.chandef.width;
835 	for (i = 0; i < max_rates; i++) {
836 		/* Skip invalid rates */
837 		if (rates[i].idx < 0)
838 			break;
839 
840 		rate_flags = rates[i].flags;
841 		rate_idx_match_mask(&rates[i].idx, &rate_flags, sband,
842 				    chan_width, mask, mcs_mask, vht_mask);
843 		rates[i].flags = rate_flags;
844 	}
845 }
846 
847 void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
848 			    struct ieee80211_sta *sta,
849 			    struct sk_buff *skb,
850 			    struct ieee80211_tx_rate *dest,
851 			    int max_rates)
852 {
853 	struct ieee80211_sub_if_data *sdata;
854 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
855 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
856 	struct ieee80211_supported_band *sband;
857 
858 	rate_control_fill_sta_table(sta, info, dest, max_rates);
859 
860 	if (!vif)
861 		return;
862 
863 	sdata = vif_to_sdata(vif);
864 	sband = sdata->local->hw.wiphy->bands[info->band];
865 
866 	if (ieee80211_is_data(hdr->frame_control))
867 		rate_control_apply_mask(sdata, sta, sband, dest, max_rates);
868 
869 	if (dest[0].idx < 0)
870 		__rate_control_send_low(&sdata->local->hw, sband, sta, info,
871 					sdata->rc_rateidx_mask[info->band]);
872 
873 	if (sta)
874 		rate_fixup_ratelist(vif, sband, info, dest, max_rates);
875 }
876 EXPORT_SYMBOL(ieee80211_get_tx_rates);
877 
878 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
879 			   struct sta_info *sta,
880 			   struct ieee80211_tx_rate_control *txrc)
881 {
882 	struct rate_control_ref *ref = sdata->local->rate_ctrl;
883 	void *priv_sta = NULL;
884 	struct ieee80211_sta *ista = NULL;
885 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
886 	int i;
887 
888 	if (sta && test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) {
889 		ista = &sta->sta;
890 		priv_sta = sta->rate_ctrl_priv;
891 	}
892 
893 	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
894 		info->control.rates[i].idx = -1;
895 		info->control.rates[i].flags = 0;
896 		info->control.rates[i].count = 0;
897 	}
898 
899 	if (ieee80211_hw_check(&sdata->local->hw, HAS_RATE_CONTROL))
900 		return;
901 
902 	if (ista) {
903 		spin_lock_bh(&sta->rate_ctrl_lock);
904 		ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
905 		spin_unlock_bh(&sta->rate_ctrl_lock);
906 	} else {
907 		ref->ops->get_rate(ref->priv, NULL, NULL, txrc);
908 	}
909 
910 	if (ieee80211_hw_check(&sdata->local->hw, SUPPORTS_RC_TABLE))
911 		return;
912 
913 	ieee80211_get_tx_rates(&sdata->vif, ista, txrc->skb,
914 			       info->control.rates,
915 			       ARRAY_SIZE(info->control.rates));
916 }
917 
918 int rate_control_set_rates(struct ieee80211_hw *hw,
919 			   struct ieee80211_sta *pubsta,
920 			   struct ieee80211_sta_rates *rates)
921 {
922 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
923 	struct ieee80211_sta_rates *old;
924 	struct ieee80211_supported_band *sband;
925 
926 	sband = ieee80211_get_sband(sta->sdata);
927 	if (!sband)
928 		return -EINVAL;
929 	rate_control_apply_mask_ratetbl(sta, sband, rates);
930 	/*
931 	 * mac80211 guarantees that this function will not be called
932 	 * concurrently, so the following RCU access is safe, even without
933 	 * extra locking. This can not be checked easily, so we just set
934 	 * the condition to true.
935 	 */
936 	old = rcu_dereference_protected(pubsta->rates, true);
937 	rcu_assign_pointer(pubsta->rates, rates);
938 	if (old)
939 		kfree_rcu(old, rcu_head);
940 
941 	drv_sta_rate_tbl_update(hw_to_local(hw), sta->sdata, pubsta);
942 
943 	ieee80211_sta_set_expected_throughput(pubsta, sta_get_expected_throughput(sta));
944 
945 	return 0;
946 }
947 EXPORT_SYMBOL(rate_control_set_rates);
948 
949 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
950 				 const char *name)
951 {
952 	struct rate_control_ref *ref;
953 
954 	ASSERT_RTNL();
955 
956 	if (local->open_count)
957 		return -EBUSY;
958 
959 	if (ieee80211_hw_check(&local->hw, HAS_RATE_CONTROL)) {
960 		if (WARN_ON(!local->ops->set_rts_threshold))
961 			return -EINVAL;
962 		return 0;
963 	}
964 
965 	ref = rate_control_alloc(name, local);
966 	if (!ref) {
967 		wiphy_warn(local->hw.wiphy,
968 			   "Failed to select rate control algorithm\n");
969 		return -ENOENT;
970 	}
971 
972 	WARN_ON(local->rate_ctrl);
973 	local->rate_ctrl = ref;
974 
975 	wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n",
976 		    ref->ops->name);
977 
978 	return 0;
979 }
980 
981 void rate_control_deinitialize(struct ieee80211_local *local)
982 {
983 	struct rate_control_ref *ref;
984 
985 	ref = local->rate_ctrl;
986 
987 	if (!ref)
988 		return;
989 
990 	local->rate_ctrl = NULL;
991 	rate_control_free(local, ref);
992 }
993