xref: /linux/net/mac80211/rate.c (revision 1b98f357dadd6ea613a435fbaef1a5dd7b35fd21)
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  * Copyright (C) 2019, 2022-2024 Intel Corporation
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/rtnetlink.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include "rate.h"
15 #include "ieee80211_i.h"
16 #include "debugfs.h"
17 
18 struct rate_control_alg {
19 	struct list_head list;
20 	const struct rate_control_ops *ops;
21 };
22 
23 static LIST_HEAD(rate_ctrl_algs);
24 static DEFINE_MUTEX(rate_ctrl_mutex);
25 
26 static char *ieee80211_default_rc_algo = CONFIG_MAC80211_RC_DEFAULT;
27 module_param(ieee80211_default_rc_algo, charp, 0644);
28 MODULE_PARM_DESC(ieee80211_default_rc_algo,
29 		 "Default rate control algorithm for mac80211 to use");
30 
31 void rate_control_rate_init(struct link_sta_info *link_sta)
32 {
33 	struct sta_info *sta = link_sta->sta;
34 	struct ieee80211_local *local = sta->sdata->local;
35 	struct rate_control_ref *ref = sta->rate_ctrl;
36 	struct ieee80211_sta *ista = &sta->sta;
37 	void *priv_sta = sta->rate_ctrl_priv;
38 	struct ieee80211_supported_band *sband;
39 	struct ieee80211_chanctx_conf *chanctx_conf;
40 
41 	ieee80211_sta_init_nss(link_sta);
42 
43 	if (!ref)
44 		return;
45 
46 	/* SW rate control isn't supported with MLO right now */
47 	if (WARN_ON(ieee80211_vif_is_mld(&sta->sdata->vif)))
48 		return;
49 
50 	rcu_read_lock();
51 
52 	chanctx_conf = rcu_dereference(sta->sdata->vif.bss_conf.chanctx_conf);
53 	if (WARN_ON(!chanctx_conf)) {
54 		rcu_read_unlock();
55 		return;
56 	}
57 
58 	sband = local->hw.wiphy->bands[chanctx_conf->def.chan->band];
59 
60 	/* TODO: check for minstrel_s1g ? */
61 	if (sband->band == NL80211_BAND_S1GHZ) {
62 		ieee80211_s1g_sta_rate_init(sta);
63 		rcu_read_unlock();
64 		return;
65 	}
66 
67 	spin_lock_bh(&sta->rate_ctrl_lock);
68 	ref->ops->rate_init(ref->priv, sband, &chanctx_conf->def, ista,
69 			    priv_sta);
70 	spin_unlock_bh(&sta->rate_ctrl_lock);
71 	rcu_read_unlock();
72 	set_sta_flag(sta, WLAN_STA_RATE_CONTROL);
73 }
74 
75 void rate_control_rate_init_all_links(struct sta_info *sta)
76 {
77 	int link_id;
78 
79 	for (link_id = 0; link_id < ARRAY_SIZE(sta->link); link_id++) {
80 		struct link_sta_info *link_sta;
81 
82 		link_sta = sdata_dereference(sta->link[link_id], sta->sdata);
83 		if (!link_sta)
84 			continue;
85 
86 		rate_control_rate_init(link_sta);
87 	}
88 }
89 
90 void rate_control_tx_status(struct ieee80211_local *local,
91 			    struct ieee80211_tx_status *st)
92 {
93 	struct rate_control_ref *ref = local->rate_ctrl;
94 	struct sta_info *sta = container_of(st->sta, struct sta_info, sta);
95 	void *priv_sta = sta->rate_ctrl_priv;
96 	struct ieee80211_supported_band *sband;
97 
98 	if (!ref || !test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
99 		return;
100 
101 	sband = local->hw.wiphy->bands[st->info->band];
102 
103 	spin_lock_bh(&sta->rate_ctrl_lock);
104 	if (ref->ops->tx_status_ext)
105 		ref->ops->tx_status_ext(ref->priv, sband, priv_sta, st);
106 	else if (st->skb)
107 		ref->ops->tx_status(ref->priv, sband, st->sta, priv_sta, st->skb);
108 	else
109 		WARN_ON_ONCE(1);
110 
111 	spin_unlock_bh(&sta->rate_ctrl_lock);
112 }
113 
114 void rate_control_rate_update(struct ieee80211_local *local,
115 			      struct ieee80211_supported_band *sband,
116 			      struct link_sta_info *link_sta,
117 			      u32 changed)
118 {
119 	struct rate_control_ref *ref = local->rate_ctrl;
120 	struct sta_info *sta = link_sta->sta;
121 	struct ieee80211_sta *ista = &sta->sta;
122 	void *priv_sta = sta->rate_ctrl_priv;
123 	struct ieee80211_chanctx_conf *chanctx_conf;
124 
125 	if (ref && ref->ops->rate_update) {
126 		rcu_read_lock();
127 
128 		chanctx_conf = rcu_dereference(sta->sdata->vif.bss_conf.chanctx_conf);
129 		if (WARN_ON(!chanctx_conf)) {
130 			rcu_read_unlock();
131 			return;
132 		}
133 
134 		spin_lock_bh(&sta->rate_ctrl_lock);
135 		ref->ops->rate_update(ref->priv, sband, &chanctx_conf->def,
136 				      ista, priv_sta, changed);
137 		spin_unlock_bh(&sta->rate_ctrl_lock);
138 		rcu_read_unlock();
139 	}
140 
141 	if (sta->uploaded)
142 		drv_link_sta_rc_update(local, sta->sdata, link_sta->pub,
143 				       changed);
144 }
145 
146 int ieee80211_rate_control_register(const struct rate_control_ops *ops)
147 {
148 	struct rate_control_alg *alg;
149 
150 	if (!ops->name)
151 		return -EINVAL;
152 
153 	mutex_lock(&rate_ctrl_mutex);
154 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
155 		if (!strcmp(alg->ops->name, ops->name)) {
156 			/* don't register an algorithm twice */
157 			WARN_ON(1);
158 			mutex_unlock(&rate_ctrl_mutex);
159 			return -EALREADY;
160 		}
161 	}
162 
163 	alg = kzalloc(sizeof(*alg), GFP_KERNEL);
164 	if (alg == NULL) {
165 		mutex_unlock(&rate_ctrl_mutex);
166 		return -ENOMEM;
167 	}
168 	alg->ops = ops;
169 
170 	list_add_tail(&alg->list, &rate_ctrl_algs);
171 	mutex_unlock(&rate_ctrl_mutex);
172 
173 	return 0;
174 }
175 EXPORT_SYMBOL(ieee80211_rate_control_register);
176 
177 void ieee80211_rate_control_unregister(const struct rate_control_ops *ops)
178 {
179 	struct rate_control_alg *alg;
180 
181 	mutex_lock(&rate_ctrl_mutex);
182 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
183 		if (alg->ops == ops) {
184 			list_del(&alg->list);
185 			kfree(alg);
186 			break;
187 		}
188 	}
189 	mutex_unlock(&rate_ctrl_mutex);
190 }
191 EXPORT_SYMBOL(ieee80211_rate_control_unregister);
192 
193 static const struct rate_control_ops *
194 ieee80211_try_rate_control_ops_get(const char *name)
195 {
196 	struct rate_control_alg *alg;
197 	const struct rate_control_ops *ops = NULL;
198 
199 	if (!name)
200 		return NULL;
201 
202 	mutex_lock(&rate_ctrl_mutex);
203 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
204 		if (!strcmp(alg->ops->name, name)) {
205 			ops = alg->ops;
206 			break;
207 		}
208 	}
209 	mutex_unlock(&rate_ctrl_mutex);
210 	return ops;
211 }
212 
213 /* Get the rate control algorithm. */
214 static const struct rate_control_ops *
215 ieee80211_rate_control_ops_get(const char *name)
216 {
217 	const struct rate_control_ops *ops;
218 	const char *alg_name;
219 
220 	kernel_param_lock(THIS_MODULE);
221 	if (!name)
222 		alg_name = ieee80211_default_rc_algo;
223 	else
224 		alg_name = name;
225 
226 	ops = ieee80211_try_rate_control_ops_get(alg_name);
227 	if (!ops && name)
228 		/* try default if specific alg requested but not found */
229 		ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);
230 
231 	/* Note: check for > 0 is intentional to avoid clang warning */
232 	if (!ops && (strlen(CONFIG_MAC80211_RC_DEFAULT) > 0))
233 		/* try built-in one if specific alg requested but not found */
234 		ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
235 
236 	kernel_param_unlock(THIS_MODULE);
237 
238 	return ops;
239 }
240 
241 #ifdef CONFIG_MAC80211_DEBUGFS
242 static ssize_t rcname_read(struct file *file, char __user *userbuf,
243 			   size_t count, loff_t *ppos)
244 {
245 	struct rate_control_ref *ref = file->private_data;
246 	int len = strlen(ref->ops->name);
247 
248 	return simple_read_from_buffer(userbuf, count, ppos,
249 				       ref->ops->name, len);
250 }
251 
252 const struct debugfs_short_fops rcname_ops = {
253 	.read = rcname_read,
254 	.llseek = default_llseek,
255 };
256 #endif
257 
258 static struct rate_control_ref *
259 rate_control_alloc(const char *name, struct ieee80211_local *local)
260 {
261 	struct rate_control_ref *ref;
262 
263 	ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
264 	if (!ref)
265 		return NULL;
266 	ref->ops = ieee80211_rate_control_ops_get(name);
267 	if (!ref->ops)
268 		goto free;
269 
270 	ref->priv = ref->ops->alloc(&local->hw);
271 	if (!ref->priv)
272 		goto free;
273 	return ref;
274 
275 free:
276 	kfree(ref);
277 	return NULL;
278 }
279 
280 static void rate_control_free(struct ieee80211_local *local,
281 			      struct rate_control_ref *ctrl_ref)
282 {
283 	ctrl_ref->ops->free(ctrl_ref->priv);
284 
285 #ifdef CONFIG_MAC80211_DEBUGFS
286 	debugfs_remove_recursive(local->debugfs.rcdir);
287 	local->debugfs.rcdir = NULL;
288 #endif
289 
290 	kfree(ctrl_ref);
291 }
292 
293 void ieee80211_check_rate_mask(struct ieee80211_link_data *link)
294 {
295 	struct ieee80211_sub_if_data *sdata = link->sdata;
296 	struct ieee80211_local *local = sdata->local;
297 	struct ieee80211_supported_band *sband;
298 	u32 user_mask, basic_rates = link->conf->basic_rates;
299 	enum nl80211_band band;
300 
301 	if (WARN_ON(!link->conf->chanreq.oper.chan))
302 		return;
303 
304 	band = link->conf->chanreq.oper.chan->band;
305 	if (band == NL80211_BAND_S1GHZ) {
306 		/* TODO */
307 		return;
308 	}
309 
310 	if (WARN_ON_ONCE(!basic_rates))
311 		return;
312 
313 	user_mask = sdata->rc_rateidx_mask[band];
314 	sband = local->hw.wiphy->bands[band];
315 
316 	if (user_mask & basic_rates)
317 		return;
318 
319 	sdata_dbg(sdata,
320 		  "no overlap between basic rates (0x%x) and user mask (0x%x on band %d) - clearing the latter",
321 		  basic_rates, user_mask, band);
322 	sdata->rc_rateidx_mask[band] = (1 << sband->n_bitrates) - 1;
323 }
324 
325 static bool rc_no_data_or_no_ack_use_min(struct ieee80211_tx_rate_control *txrc)
326 {
327 	struct sk_buff *skb = txrc->skb;
328 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
329 
330 	return (info->flags & (IEEE80211_TX_CTL_NO_ACK |
331 			       IEEE80211_TX_CTL_USE_MINRATE)) ||
332 		!ieee80211_is_tx_data(skb);
333 }
334 
335 static void rc_send_low_basicrate(struct ieee80211_tx_rate *rate,
336 				  u32 basic_rates,
337 				  struct ieee80211_supported_band *sband)
338 {
339 	u8 i;
340 
341 	if (sband->band == NL80211_BAND_S1GHZ) {
342 		/* TODO */
343 		rate->flags |= IEEE80211_TX_RC_S1G_MCS;
344 		rate->idx = 0;
345 		return;
346 	}
347 
348 	if (basic_rates == 0)
349 		return; /* assume basic rates unknown and accept rate */
350 	if (rate->idx < 0)
351 		return;
352 	if (basic_rates & (1 << rate->idx))
353 		return; /* selected rate is a basic rate */
354 
355 	for (i = rate->idx + 1; i <= sband->n_bitrates; i++) {
356 		if (basic_rates & (1 << i)) {
357 			rate->idx = i;
358 			return;
359 		}
360 	}
361 
362 	/* could not find a basic rate; use original selection */
363 }
364 
365 static void __rate_control_send_low(struct ieee80211_hw *hw,
366 				    struct ieee80211_supported_band *sband,
367 				    struct ieee80211_sta *sta,
368 				    struct ieee80211_tx_info *info,
369 				    u32 rate_mask)
370 {
371 	u32 rate_flags = 0;
372 	int i;
373 
374 	if (sband->band == NL80211_BAND_S1GHZ) {
375 		info->control.rates[0].flags |= IEEE80211_TX_RC_S1G_MCS;
376 		info->control.rates[0].idx = 0;
377 		return;
378 	}
379 
380 	if ((sband->band == NL80211_BAND_2GHZ) &&
381 	    (info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
382 		rate_flags |= IEEE80211_RATE_ERP_G;
383 
384 	info->control.rates[0].idx = 0;
385 	for (i = 0; i < sband->n_bitrates; i++) {
386 		if (!(rate_mask & BIT(i)))
387 			continue;
388 
389 		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
390 			continue;
391 
392 		if (!rate_supported(sta, sband->band, i))
393 			continue;
394 
395 		info->control.rates[0].idx = i;
396 		break;
397 	}
398 	WARN_ONCE(i == sband->n_bitrates,
399 		  "no supported rates for sta %pM (0x%x, band %d) in rate_mask 0x%x with flags 0x%x\n",
400 		  sta ? sta->addr : NULL,
401 		  sta ? sta->deflink.supp_rates[sband->band] : -1,
402 		  sband->band,
403 		  rate_mask, rate_flags);
404 
405 	info->control.rates[0].count =
406 		(info->flags & IEEE80211_TX_CTL_NO_ACK) ?
407 		1 : hw->max_rate_tries;
408 
409 	info->control.skip_table = 1;
410 }
411 
412 
413 static bool rate_control_send_low(struct ieee80211_sta *pubsta,
414 				  struct ieee80211_tx_rate_control *txrc)
415 {
416 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
417 	struct ieee80211_supported_band *sband = txrc->sband;
418 	struct sta_info *sta;
419 	int mcast_rate;
420 	bool use_basicrate = false;
421 
422 	if (!pubsta || rc_no_data_or_no_ack_use_min(txrc)) {
423 		__rate_control_send_low(txrc->hw, sband, pubsta, info,
424 					txrc->rate_idx_mask);
425 
426 		if (!pubsta && txrc->bss) {
427 			mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
428 			if (mcast_rate > 0) {
429 				info->control.rates[0].idx = mcast_rate - 1;
430 				return true;
431 			}
432 			use_basicrate = true;
433 		} else if (pubsta) {
434 			sta = container_of(pubsta, struct sta_info, sta);
435 			if (ieee80211_vif_is_mesh(&sta->sdata->vif))
436 				use_basicrate = true;
437 		}
438 
439 		if (use_basicrate)
440 			rc_send_low_basicrate(&info->control.rates[0],
441 					      txrc->bss_conf->basic_rates,
442 					      sband);
443 
444 		return true;
445 	}
446 	return false;
447 }
448 
449 static bool rate_idx_match_legacy_mask(s8 *rate_idx, int n_bitrates, u32 mask)
450 {
451 	int j;
452 
453 	/* See whether the selected rate or anything below it is allowed. */
454 	for (j = *rate_idx; j >= 0; j--) {
455 		if (mask & (1 << j)) {
456 			/* Okay, found a suitable rate. Use it. */
457 			*rate_idx = j;
458 			return true;
459 		}
460 	}
461 
462 	/* Try to find a higher rate that would be allowed */
463 	for (j = *rate_idx + 1; j < n_bitrates; j++) {
464 		if (mask & (1 << j)) {
465 			/* Okay, found a suitable rate. Use it. */
466 			*rate_idx = j;
467 			return true;
468 		}
469 	}
470 	return false;
471 }
472 
473 static bool rate_idx_match_mcs_mask(s8 *rate_idx, u8 *mcs_mask)
474 {
475 	int i, j;
476 	int ridx, rbit;
477 
478 	ridx = *rate_idx / 8;
479 	rbit = *rate_idx % 8;
480 
481 	/* sanity check */
482 	if (ridx < 0 || ridx >= IEEE80211_HT_MCS_MASK_LEN)
483 		return false;
484 
485 	/* See whether the selected rate or anything below it is allowed. */
486 	for (i = ridx; i >= 0; i--) {
487 		for (j = rbit; j >= 0; j--)
488 			if (mcs_mask[i] & BIT(j)) {
489 				*rate_idx = i * 8 + j;
490 				return true;
491 			}
492 		rbit = 7;
493 	}
494 
495 	/* Try to find a higher rate that would be allowed */
496 	ridx = (*rate_idx + 1) / 8;
497 	rbit = (*rate_idx + 1) % 8;
498 
499 	for (i = ridx; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
500 		for (j = rbit; j < 8; j++)
501 			if (mcs_mask[i] & BIT(j)) {
502 				*rate_idx = i * 8 + j;
503 				return true;
504 			}
505 		rbit = 0;
506 	}
507 	return false;
508 }
509 
510 static bool rate_idx_match_vht_mcs_mask(s8 *rate_idx, u16 *vht_mask)
511 {
512 	int i, j;
513 	int ridx, rbit;
514 
515 	ridx = *rate_idx >> 4;
516 	rbit = *rate_idx & 0xf;
517 
518 	if (ridx < 0 || ridx >= NL80211_VHT_NSS_MAX)
519 		return false;
520 
521 	/* See whether the selected rate or anything below it is allowed. */
522 	for (i = ridx; i >= 0; i--) {
523 		for (j = rbit; j >= 0; j--) {
524 			if (vht_mask[i] & BIT(j)) {
525 				*rate_idx = (i << 4) | j;
526 				return true;
527 			}
528 		}
529 		rbit = 15;
530 	}
531 
532 	/* Try to find a higher rate that would be allowed */
533 	ridx = (*rate_idx + 1) >> 4;
534 	rbit = (*rate_idx + 1) & 0xf;
535 
536 	for (i = ridx; i < NL80211_VHT_NSS_MAX; i++) {
537 		for (j = rbit; j < 16; j++) {
538 			if (vht_mask[i] & BIT(j)) {
539 				*rate_idx = (i << 4) | j;
540 				return true;
541 			}
542 		}
543 		rbit = 0;
544 	}
545 	return false;
546 }
547 
548 static void rate_idx_match_mask(s8 *rate_idx, u16 *rate_flags,
549 				struct ieee80211_supported_band *sband,
550 				enum nl80211_chan_width chan_width,
551 				u32 mask,
552 				u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN],
553 				u16 vht_mask[NL80211_VHT_NSS_MAX])
554 {
555 	if (*rate_flags & IEEE80211_TX_RC_VHT_MCS) {
556 		/* handle VHT rates */
557 		if (rate_idx_match_vht_mcs_mask(rate_idx, vht_mask))
558 			return;
559 
560 		*rate_idx = 0;
561 		/* keep protection flags */
562 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
563 				IEEE80211_TX_RC_USE_CTS_PROTECT |
564 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
565 
566 		*rate_flags |= IEEE80211_TX_RC_MCS;
567 		if (chan_width == NL80211_CHAN_WIDTH_40)
568 			*rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
569 
570 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
571 			return;
572 
573 		/* also try the legacy rates. */
574 		*rate_flags &= ~(IEEE80211_TX_RC_MCS |
575 				 IEEE80211_TX_RC_40_MHZ_WIDTH);
576 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
577 					       mask))
578 			return;
579 	} else if (*rate_flags & IEEE80211_TX_RC_MCS) {
580 		/* handle HT rates */
581 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
582 			return;
583 
584 		/* also try the legacy rates. */
585 		*rate_idx = 0;
586 		/* keep protection flags */
587 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
588 				IEEE80211_TX_RC_USE_CTS_PROTECT |
589 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
590 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
591 					       mask))
592 			return;
593 	} else {
594 		/* handle legacy rates */
595 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
596 					       mask))
597 			return;
598 
599 		/* if HT BSS, and we handle a data frame, also try HT rates */
600 		switch (chan_width) {
601 		case NL80211_CHAN_WIDTH_20_NOHT:
602 		case NL80211_CHAN_WIDTH_5:
603 		case NL80211_CHAN_WIDTH_10:
604 			return;
605 		default:
606 			break;
607 		}
608 
609 		*rate_idx = 0;
610 		/* keep protection flags */
611 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
612 				IEEE80211_TX_RC_USE_CTS_PROTECT |
613 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
614 
615 		*rate_flags |= IEEE80211_TX_RC_MCS;
616 
617 		if (chan_width == NL80211_CHAN_WIDTH_40)
618 			*rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
619 
620 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
621 			return;
622 	}
623 
624 	/*
625 	 * Uh.. No suitable rate exists. This should not really happen with
626 	 * sane TX rate mask configurations. However, should someone manage to
627 	 * configure supported rates and TX rate mask in incompatible way,
628 	 * allow the frame to be transmitted with whatever the rate control
629 	 * selected.
630 	 */
631 }
632 
633 static void rate_fixup_ratelist(struct ieee80211_vif *vif,
634 				struct ieee80211_supported_band *sband,
635 				struct ieee80211_tx_info *info,
636 				struct ieee80211_tx_rate *rates,
637 				int max_rates)
638 {
639 	struct ieee80211_rate *rate;
640 	bool inval = false;
641 	int i;
642 
643 	/*
644 	 * Set up the RTS/CTS rate as the fastest basic rate
645 	 * that is not faster than the data rate unless there
646 	 * is no basic rate slower than the data rate, in which
647 	 * case we pick the slowest basic rate
648 	 *
649 	 * XXX: Should this check all retry rates?
650 	 */
651 	if (!(rates[0].flags &
652 	      (IEEE80211_TX_RC_MCS | IEEE80211_TX_RC_VHT_MCS))) {
653 		u32 basic_rates = vif->bss_conf.basic_rates;
654 		s8 baserate = basic_rates ? ffs(basic_rates) - 1 : 0;
655 
656 		rate = &sband->bitrates[rates[0].idx];
657 
658 		for (i = 0; i < sband->n_bitrates; i++) {
659 			/* must be a basic rate */
660 			if (!(basic_rates & BIT(i)))
661 				continue;
662 			/* must not be faster than the data rate */
663 			if (sband->bitrates[i].bitrate > rate->bitrate)
664 				continue;
665 			/* maximum */
666 			if (sband->bitrates[baserate].bitrate <
667 			     sband->bitrates[i].bitrate)
668 				baserate = i;
669 		}
670 
671 		info->control.rts_cts_rate_idx = baserate;
672 	}
673 
674 	for (i = 0; i < max_rates; i++) {
675 		/*
676 		 * make sure there's no valid rate following
677 		 * an invalid one, just in case drivers don't
678 		 * take the API seriously to stop at -1.
679 		 */
680 		if (inval) {
681 			rates[i].idx = -1;
682 			continue;
683 		}
684 		if (rates[i].idx < 0) {
685 			inval = true;
686 			continue;
687 		}
688 
689 		/*
690 		 * For now assume MCS is already set up correctly, this
691 		 * needs to be fixed.
692 		 */
693 		if (rates[i].flags & IEEE80211_TX_RC_MCS) {
694 			WARN_ON(rates[i].idx > 76);
695 
696 			if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
697 			    info->control.use_cts_prot)
698 				rates[i].flags |=
699 					IEEE80211_TX_RC_USE_CTS_PROTECT;
700 			continue;
701 		}
702 
703 		if (rates[i].flags & IEEE80211_TX_RC_VHT_MCS) {
704 			WARN_ON(ieee80211_rate_get_vht_mcs(&rates[i]) > 9);
705 			continue;
706 		}
707 
708 		/* set up RTS protection if desired */
709 		if (info->control.use_rts) {
710 			rates[i].flags |= IEEE80211_TX_RC_USE_RTS_CTS;
711 			info->control.use_cts_prot = false;
712 		}
713 
714 		/* RC is busted */
715 		if (WARN_ON_ONCE(rates[i].idx >= sband->n_bitrates)) {
716 			rates[i].idx = -1;
717 			continue;
718 		}
719 
720 		rate = &sband->bitrates[rates[i].idx];
721 
722 		/* set up short preamble */
723 		if (info->control.short_preamble &&
724 		    rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
725 			rates[i].flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
726 
727 		/* set up G protection */
728 		if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
729 		    info->control.use_cts_prot &&
730 		    rate->flags & IEEE80211_RATE_ERP_G)
731 			rates[i].flags |= IEEE80211_TX_RC_USE_CTS_PROTECT;
732 	}
733 }
734 
735 
736 static void rate_control_fill_sta_table(struct ieee80211_sta *sta,
737 					struct ieee80211_tx_info *info,
738 					struct ieee80211_tx_rate *rates,
739 					int max_rates)
740 {
741 	struct ieee80211_sta_rates *ratetbl = NULL;
742 	int i;
743 
744 	if (sta && !info->control.skip_table)
745 		ratetbl = rcu_dereference(sta->rates);
746 
747 	/* Fill remaining rate slots with data from the sta rate table. */
748 	max_rates = min_t(int, max_rates, IEEE80211_TX_RATE_TABLE_SIZE);
749 	for (i = 0; i < max_rates; i++) {
750 		if (i < ARRAY_SIZE(info->control.rates) &&
751 		    info->control.rates[i].idx >= 0 &&
752 		    info->control.rates[i].count) {
753 			if (rates != info->control.rates)
754 				rates[i] = info->control.rates[i];
755 		} else if (ratetbl) {
756 			rates[i].idx = ratetbl->rate[i].idx;
757 			rates[i].flags = ratetbl->rate[i].flags;
758 			if (info->control.use_rts)
759 				rates[i].count = ratetbl->rate[i].count_rts;
760 			else if (info->control.use_cts_prot)
761 				rates[i].count = ratetbl->rate[i].count_cts;
762 			else
763 				rates[i].count = ratetbl->rate[i].count;
764 		} else {
765 			rates[i].idx = -1;
766 			rates[i].count = 0;
767 		}
768 
769 		if (rates[i].idx < 0 || !rates[i].count)
770 			break;
771 	}
772 }
773 
774 static bool rate_control_cap_mask(struct ieee80211_sub_if_data *sdata,
775 				  struct ieee80211_supported_band *sband,
776 				  struct ieee80211_sta *sta, u32 *mask,
777 				  u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN],
778 				  u16 vht_mask[NL80211_VHT_NSS_MAX])
779 {
780 	u32 i;
781 
782 	*mask = sdata->rc_rateidx_mask[sband->band];
783 
784 	if (*mask == (1 << sband->n_bitrates) - 1 &&
785 	    !sdata->rc_has_mcs_mask[sband->band] &&
786 	    !sdata->rc_has_vht_mcs_mask[sband->band])
787 		return false;
788 
789 	if (sdata->rc_has_mcs_mask[sband->band])
790 		memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[sband->band],
791 		       IEEE80211_HT_MCS_MASK_LEN);
792 	else
793 		memset(mcs_mask, 0xff, IEEE80211_HT_MCS_MASK_LEN);
794 
795 	if (sdata->rc_has_vht_mcs_mask[sband->band])
796 		memcpy(vht_mask, sdata->rc_rateidx_vht_mcs_mask[sband->band],
797 		       sizeof(u16) * NL80211_VHT_NSS_MAX);
798 	else
799 		memset(vht_mask, 0xff, sizeof(u16) * NL80211_VHT_NSS_MAX);
800 
801 	if (sta) {
802 		__le16 sta_vht_cap;
803 		u16 sta_vht_mask[NL80211_VHT_NSS_MAX];
804 
805 		/* Filter out rates that the STA does not support */
806 		*mask &= sta->deflink.supp_rates[sband->band];
807 		for (i = 0; i < IEEE80211_HT_MCS_MASK_LEN; i++)
808 			mcs_mask[i] &= sta->deflink.ht_cap.mcs.rx_mask[i];
809 
810 		sta_vht_cap = sta->deflink.vht_cap.vht_mcs.rx_mcs_map;
811 		ieee80211_get_vht_mask_from_cap(sta_vht_cap, sta_vht_mask);
812 		for (i = 0; i < NL80211_VHT_NSS_MAX; i++)
813 			vht_mask[i] &= sta_vht_mask[i];
814 	}
815 
816 	return true;
817 }
818 
819 static void
820 rate_control_apply_mask_ratetbl(struct sta_info *sta,
821 				struct ieee80211_supported_band *sband,
822 				struct ieee80211_sta_rates *rates)
823 {
824 	int i;
825 	u32 mask;
826 	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
827 	u16 vht_mask[NL80211_VHT_NSS_MAX];
828 	enum nl80211_chan_width chan_width;
829 
830 	if (!rate_control_cap_mask(sta->sdata, sband, &sta->sta, &mask,
831 				   mcs_mask, vht_mask))
832 		return;
833 
834 	chan_width = sta->sdata->vif.bss_conf.chanreq.oper.width;
835 	for (i = 0; i < IEEE80211_TX_RATE_TABLE_SIZE; i++) {
836 		if (rates->rate[i].idx < 0)
837 			break;
838 
839 		rate_idx_match_mask(&rates->rate[i].idx, &rates->rate[i].flags,
840 				    sband, chan_width, mask, mcs_mask,
841 				    vht_mask);
842 	}
843 }
844 
845 static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
846 				    struct ieee80211_sta *sta,
847 				    struct ieee80211_supported_band *sband,
848 				    struct ieee80211_tx_rate *rates,
849 				    int max_rates)
850 {
851 	enum nl80211_chan_width chan_width;
852 	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
853 	u32 mask;
854 	u16 rate_flags, vht_mask[NL80211_VHT_NSS_MAX];
855 	int i;
856 
857 	/*
858 	 * Try to enforce the rateidx mask the user wanted. skip this if the
859 	 * default mask (allow all rates) is used to save some processing for
860 	 * the common case.
861 	 */
862 	if (!rate_control_cap_mask(sdata, sband, sta, &mask, mcs_mask,
863 				   vht_mask))
864 		return;
865 
866 	/*
867 	 * Make sure the rate index selected for each TX rate is
868 	 * included in the configured mask and change the rate indexes
869 	 * if needed.
870 	 */
871 	chan_width = sdata->vif.bss_conf.chanreq.oper.width;
872 	for (i = 0; i < max_rates; i++) {
873 		/* Skip invalid rates */
874 		if (rates[i].idx < 0)
875 			break;
876 
877 		rate_flags = rates[i].flags;
878 		rate_idx_match_mask(&rates[i].idx, &rate_flags, sband,
879 				    chan_width, mask, mcs_mask, vht_mask);
880 		rates[i].flags = rate_flags;
881 	}
882 }
883 
884 void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
885 			    struct ieee80211_sta *sta,
886 			    struct sk_buff *skb,
887 			    struct ieee80211_tx_rate *dest,
888 			    int max_rates)
889 {
890 	struct ieee80211_sub_if_data *sdata;
891 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
892 	struct ieee80211_supported_band *sband;
893 	u32 mask = ~0;
894 
895 	rate_control_fill_sta_table(sta, info, dest, max_rates);
896 
897 	if (!vif)
898 		return;
899 
900 	sdata = vif_to_sdata(vif);
901 	sband = sdata->local->hw.wiphy->bands[info->band];
902 
903 	if (ieee80211_is_tx_data(skb))
904 		rate_control_apply_mask(sdata, sta, sband, dest, max_rates);
905 
906 	if (!(info->control.flags & IEEE80211_TX_CTRL_DONT_USE_RATE_MASK))
907 		mask = sdata->rc_rateidx_mask[info->band];
908 
909 	if (dest[0].idx < 0)
910 		__rate_control_send_low(&sdata->local->hw, sband, sta, info,
911 					mask);
912 
913 	if (sta)
914 		rate_fixup_ratelist(vif, sband, info, dest, max_rates);
915 }
916 EXPORT_SYMBOL(ieee80211_get_tx_rates);
917 
918 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
919 			   struct sta_info *sta,
920 			   struct ieee80211_tx_rate_control *txrc)
921 {
922 	struct rate_control_ref *ref = sdata->local->rate_ctrl;
923 	void *priv_sta = NULL;
924 	struct ieee80211_sta *ista = NULL;
925 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
926 	int i;
927 
928 	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
929 		info->control.rates[i].idx = -1;
930 		info->control.rates[i].flags = 0;
931 		info->control.rates[i].count = 0;
932 	}
933 
934 	if (rate_control_send_low(sta ? &sta->sta : NULL, txrc))
935 		return;
936 
937 	if (ieee80211_hw_check(&sdata->local->hw, HAS_RATE_CONTROL))
938 		return;
939 
940 	if (sta && test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) {
941 		ista = &sta->sta;
942 		priv_sta = sta->rate_ctrl_priv;
943 	}
944 
945 	if (ista) {
946 		spin_lock_bh(&sta->rate_ctrl_lock);
947 		ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
948 		spin_unlock_bh(&sta->rate_ctrl_lock);
949 	} else {
950 		rate_control_send_low(NULL, txrc);
951 	}
952 
953 	if (ieee80211_hw_check(&sdata->local->hw, SUPPORTS_RC_TABLE))
954 		return;
955 
956 	ieee80211_get_tx_rates(&sdata->vif, ista, txrc->skb,
957 			       info->control.rates,
958 			       ARRAY_SIZE(info->control.rates));
959 }
960 
961 int rate_control_set_rates(struct ieee80211_hw *hw,
962 			   struct ieee80211_sta *pubsta,
963 			   struct ieee80211_sta_rates *rates)
964 {
965 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
966 	struct ieee80211_sta_rates *old;
967 	struct ieee80211_supported_band *sband;
968 
969 	sband = ieee80211_get_sband(sta->sdata);
970 	if (!sband)
971 		return -EINVAL;
972 	rate_control_apply_mask_ratetbl(sta, sband, rates);
973 	/*
974 	 * mac80211 guarantees that this function will not be called
975 	 * concurrently, so the following RCU access is safe, even without
976 	 * extra locking. This can not be checked easily, so we just set
977 	 * the condition to true.
978 	 */
979 	old = rcu_dereference_protected(pubsta->rates, true);
980 	rcu_assign_pointer(pubsta->rates, rates);
981 	if (old)
982 		kfree_rcu(old, rcu_head);
983 
984 	if (sta->uploaded)
985 		drv_sta_rate_tbl_update(hw_to_local(hw), sta->sdata, pubsta);
986 
987 	return 0;
988 }
989 EXPORT_SYMBOL(rate_control_set_rates);
990 
991 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
992 				 const char *name)
993 {
994 	struct rate_control_ref *ref;
995 
996 	ASSERT_RTNL();
997 
998 	if (local->open_count)
999 		return -EBUSY;
1000 
1001 	if (ieee80211_hw_check(&local->hw, HAS_RATE_CONTROL)) {
1002 		if (WARN_ON(!local->ops->set_rts_threshold))
1003 			return -EINVAL;
1004 		return 0;
1005 	}
1006 
1007 	ref = rate_control_alloc(name, local);
1008 	if (!ref) {
1009 		wiphy_warn(local->hw.wiphy,
1010 			   "Failed to select rate control algorithm\n");
1011 		return -ENOENT;
1012 	}
1013 
1014 	WARN_ON(local->rate_ctrl);
1015 	local->rate_ctrl = ref;
1016 
1017 	wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n",
1018 		    ref->ops->name);
1019 
1020 	return 0;
1021 }
1022 
1023 void rate_control_deinitialize(struct ieee80211_local *local)
1024 {
1025 	struct rate_control_ref *ref;
1026 
1027 	ref = local->rate_ctrl;
1028 
1029 	if (!ref)
1030 		return;
1031 
1032 	local->rate_ctrl = NULL;
1033 	rate_control_free(local, ref);
1034 }
1035