xref: /linux/net/mac80211/rate.c (revision 07fdad3a93756b872da7b53647715c48d0f4a2d0)
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, 2022-2025 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 	if (st->info->band >= NUM_NL80211_BANDS)
102 		return;
103 
104 	sband = local->hw.wiphy->bands[st->info->band];
105 
106 	spin_lock_bh(&sta->rate_ctrl_lock);
107 	if (ref->ops->tx_status_ext)
108 		ref->ops->tx_status_ext(ref->priv, sband, priv_sta, st);
109 	else if (st->skb)
110 		ref->ops->tx_status(ref->priv, sband, st->sta, priv_sta, st->skb);
111 	else
112 		WARN_ON_ONCE(1);
113 
114 	spin_unlock_bh(&sta->rate_ctrl_lock);
115 }
116 
117 void rate_control_rate_update(struct ieee80211_local *local,
118 			      struct ieee80211_supported_band *sband,
119 			      struct link_sta_info *link_sta,
120 			      u32 changed)
121 {
122 	struct rate_control_ref *ref = local->rate_ctrl;
123 	struct sta_info *sta = link_sta->sta;
124 	struct ieee80211_sta *ista = &sta->sta;
125 	void *priv_sta = sta->rate_ctrl_priv;
126 	struct ieee80211_chanctx_conf *chanctx_conf;
127 
128 	if (ref && ref->ops->rate_update) {
129 		rcu_read_lock();
130 
131 		chanctx_conf = rcu_dereference(sta->sdata->vif.bss_conf.chanctx_conf);
132 		if (WARN_ON(!chanctx_conf)) {
133 			rcu_read_unlock();
134 			return;
135 		}
136 
137 		spin_lock_bh(&sta->rate_ctrl_lock);
138 		ref->ops->rate_update(ref->priv, sband, &chanctx_conf->def,
139 				      ista, priv_sta, changed);
140 		spin_unlock_bh(&sta->rate_ctrl_lock);
141 		rcu_read_unlock();
142 	}
143 
144 	if (sta->uploaded)
145 		drv_link_sta_rc_update(local, sta->sdata, link_sta->pub,
146 				       changed);
147 }
148 
149 int ieee80211_rate_control_register(const struct rate_control_ops *ops)
150 {
151 	struct rate_control_alg *alg;
152 
153 	if (!ops->name)
154 		return -EINVAL;
155 
156 	mutex_lock(&rate_ctrl_mutex);
157 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
158 		if (!strcmp(alg->ops->name, ops->name)) {
159 			/* don't register an algorithm twice */
160 			WARN_ON(1);
161 			mutex_unlock(&rate_ctrl_mutex);
162 			return -EALREADY;
163 		}
164 	}
165 
166 	alg = kzalloc(sizeof(*alg), GFP_KERNEL);
167 	if (alg == NULL) {
168 		mutex_unlock(&rate_ctrl_mutex);
169 		return -ENOMEM;
170 	}
171 	alg->ops = ops;
172 
173 	list_add_tail(&alg->list, &rate_ctrl_algs);
174 	mutex_unlock(&rate_ctrl_mutex);
175 
176 	return 0;
177 }
178 EXPORT_SYMBOL(ieee80211_rate_control_register);
179 
180 void ieee80211_rate_control_unregister(const struct rate_control_ops *ops)
181 {
182 	struct rate_control_alg *alg;
183 
184 	mutex_lock(&rate_ctrl_mutex);
185 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
186 		if (alg->ops == ops) {
187 			list_del(&alg->list);
188 			kfree(alg);
189 			break;
190 		}
191 	}
192 	mutex_unlock(&rate_ctrl_mutex);
193 }
194 EXPORT_SYMBOL(ieee80211_rate_control_unregister);
195 
196 static const struct rate_control_ops *
197 ieee80211_try_rate_control_ops_get(const char *name)
198 {
199 	struct rate_control_alg *alg;
200 	const struct rate_control_ops *ops = NULL;
201 
202 	if (!name)
203 		return NULL;
204 
205 	mutex_lock(&rate_ctrl_mutex);
206 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
207 		if (!strcmp(alg->ops->name, name)) {
208 			ops = alg->ops;
209 			break;
210 		}
211 	}
212 	mutex_unlock(&rate_ctrl_mutex);
213 	return ops;
214 }
215 
216 /* Get the rate control algorithm. */
217 static const struct rate_control_ops *
218 ieee80211_rate_control_ops_get(const char *name)
219 {
220 	const struct rate_control_ops *ops;
221 	const char *alg_name;
222 
223 	kernel_param_lock(THIS_MODULE);
224 	if (!name)
225 		alg_name = ieee80211_default_rc_algo;
226 	else
227 		alg_name = name;
228 
229 	ops = ieee80211_try_rate_control_ops_get(alg_name);
230 	if (!ops && name)
231 		/* try default if specific alg requested but not found */
232 		ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);
233 
234 	/* Note: check for > 0 is intentional to avoid clang warning */
235 	if (!ops && (strlen(CONFIG_MAC80211_RC_DEFAULT) > 0))
236 		/* try built-in one if specific alg requested but not found */
237 		ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
238 
239 	kernel_param_unlock(THIS_MODULE);
240 
241 	return ops;
242 }
243 
244 #ifdef CONFIG_MAC80211_DEBUGFS
245 static ssize_t rcname_read(struct file *file, char __user *userbuf,
246 			   size_t count, loff_t *ppos)
247 {
248 	struct rate_control_ref *ref = file->private_data;
249 	int len = strlen(ref->ops->name);
250 
251 	return simple_read_from_buffer(userbuf, count, ppos,
252 				       ref->ops->name, len);
253 }
254 
255 const struct debugfs_short_fops rcname_ops = {
256 	.read = rcname_read,
257 	.llseek = default_llseek,
258 };
259 #endif
260 
261 static struct rate_control_ref *
262 rate_control_alloc(const char *name, struct ieee80211_local *local)
263 {
264 	struct rate_control_ref *ref;
265 
266 	ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
267 	if (!ref)
268 		return NULL;
269 	ref->ops = ieee80211_rate_control_ops_get(name);
270 	if (!ref->ops)
271 		goto free;
272 
273 	ref->priv = ref->ops->alloc(&local->hw);
274 	if (!ref->priv)
275 		goto free;
276 	return ref;
277 
278 free:
279 	kfree(ref);
280 	return NULL;
281 }
282 
283 static void rate_control_free(struct ieee80211_local *local,
284 			      struct rate_control_ref *ctrl_ref)
285 {
286 	ctrl_ref->ops->free(ctrl_ref->priv);
287 
288 #ifdef CONFIG_MAC80211_DEBUGFS
289 	debugfs_remove_recursive(local->debugfs.rcdir);
290 	local->debugfs.rcdir = NULL;
291 #endif
292 
293 	kfree(ctrl_ref);
294 }
295 
296 void ieee80211_check_rate_mask(struct ieee80211_link_data *link)
297 {
298 	struct ieee80211_sub_if_data *sdata = link->sdata;
299 	struct ieee80211_local *local = sdata->local;
300 	struct ieee80211_supported_band *sband;
301 	u32 user_mask, basic_rates = link->conf->basic_rates;
302 	enum nl80211_band band;
303 
304 	if (WARN_ON(!link->conf->chanreq.oper.chan))
305 		return;
306 
307 	band = link->conf->chanreq.oper.chan->band;
308 	if (band == NL80211_BAND_S1GHZ) {
309 		/* TODO */
310 		return;
311 	}
312 
313 	if (WARN_ON_ONCE(!basic_rates))
314 		return;
315 
316 	user_mask = sdata->rc_rateidx_mask[band];
317 	sband = local->hw.wiphy->bands[band];
318 
319 	if (user_mask & basic_rates)
320 		return;
321 
322 	sdata_dbg(sdata,
323 		  "no overlap between basic rates (0x%x) and user mask (0x%x on band %d) - clearing the latter",
324 		  basic_rates, user_mask, band);
325 	sdata->rc_rateidx_mask[band] = (1 << sband->n_bitrates) - 1;
326 }
327 
328 static bool rc_no_data_or_no_ack_use_min(struct ieee80211_tx_rate_control *txrc)
329 {
330 	struct sk_buff *skb = txrc->skb;
331 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
332 
333 	return (info->flags & (IEEE80211_TX_CTL_NO_ACK |
334 			       IEEE80211_TX_CTL_USE_MINRATE)) ||
335 		!ieee80211_is_tx_data(skb);
336 }
337 
338 static void rc_send_low_basicrate(struct ieee80211_tx_rate *rate,
339 				  u32 basic_rates,
340 				  struct ieee80211_supported_band *sband)
341 {
342 	u8 i;
343 
344 	if (sband->band == NL80211_BAND_S1GHZ) {
345 		/* TODO */
346 		rate->flags |= IEEE80211_TX_RC_S1G_MCS;
347 		rate->idx = 0;
348 		return;
349 	}
350 
351 	if (basic_rates == 0)
352 		return; /* assume basic rates unknown and accept rate */
353 	if (rate->idx < 0)
354 		return;
355 	if (basic_rates & (1 << rate->idx))
356 		return; /* selected rate is a basic rate */
357 
358 	for (i = rate->idx + 1; i <= sband->n_bitrates; i++) {
359 		if (basic_rates & (1 << i)) {
360 			rate->idx = i;
361 			return;
362 		}
363 	}
364 
365 	/* could not find a basic rate; use original selection */
366 }
367 
368 static void __rate_control_send_low(struct ieee80211_hw *hw,
369 				    struct ieee80211_supported_band *sband,
370 				    struct ieee80211_sta *sta,
371 				    struct ieee80211_tx_info *info,
372 				    u32 rate_mask)
373 {
374 	u32 rate_flags = 0;
375 	int i;
376 
377 	if (sband->band == NL80211_BAND_S1GHZ) {
378 		info->control.rates[0].flags |= IEEE80211_TX_RC_S1G_MCS;
379 		info->control.rates[0].idx = 0;
380 		return;
381 	}
382 
383 	if ((sband->band == NL80211_BAND_2GHZ) &&
384 	    (info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
385 		rate_flags |= IEEE80211_RATE_ERP_G;
386 
387 	info->control.rates[0].idx = 0;
388 	for (i = 0; i < sband->n_bitrates; i++) {
389 		if (!(rate_mask & BIT(i)))
390 			continue;
391 
392 		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
393 			continue;
394 
395 		if (!rate_supported(sta, sband->band, i))
396 			continue;
397 
398 		info->control.rates[0].idx = i;
399 		break;
400 	}
401 	WARN_ONCE(i == sband->n_bitrates,
402 		  "no supported rates for sta %pM (0x%x, band %d) in rate_mask 0x%x with flags 0x%x\n",
403 		  sta ? sta->addr : NULL,
404 		  sta ? sta->deflink.supp_rates[sband->band] : -1,
405 		  sband->band,
406 		  rate_mask, rate_flags);
407 
408 	info->control.rates[0].count =
409 		(info->flags & IEEE80211_TX_CTL_NO_ACK) ?
410 		1 : hw->max_rate_tries;
411 
412 	info->control.skip_table = 1;
413 }
414 
415 
416 static bool rate_control_send_low(struct ieee80211_sta *pubsta,
417 				  struct ieee80211_tx_rate_control *txrc)
418 {
419 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
420 	struct ieee80211_supported_band *sband = txrc->sband;
421 	struct sta_info *sta;
422 	int mcast_rate;
423 	bool use_basicrate = false;
424 
425 	if (!sband)
426 		return false;
427 
428 	if (!pubsta || rc_no_data_or_no_ack_use_min(txrc)) {
429 		__rate_control_send_low(txrc->hw, sband, pubsta, info,
430 					txrc->rate_idx_mask);
431 
432 		if (!pubsta && txrc->bss) {
433 			mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
434 			if (mcast_rate > 0) {
435 				info->control.rates[0].idx = mcast_rate - 1;
436 				return true;
437 			}
438 			use_basicrate = true;
439 		} else if (pubsta) {
440 			sta = container_of(pubsta, struct sta_info, sta);
441 			if (ieee80211_vif_is_mesh(&sta->sdata->vif))
442 				use_basicrate = true;
443 		}
444 
445 		if (use_basicrate)
446 			rc_send_low_basicrate(&info->control.rates[0],
447 					      txrc->bss_conf->basic_rates,
448 					      sband);
449 
450 		return true;
451 	}
452 	return false;
453 }
454 
455 static bool rate_idx_match_legacy_mask(s8 *rate_idx, int n_bitrates, u32 mask)
456 {
457 	int j;
458 
459 	/* See whether the selected rate or anything below it is allowed. */
460 	for (j = *rate_idx; j >= 0; j--) {
461 		if (mask & (1 << j)) {
462 			/* Okay, found a suitable rate. Use it. */
463 			*rate_idx = j;
464 			return true;
465 		}
466 	}
467 
468 	/* Try to find a higher rate that would be allowed */
469 	for (j = *rate_idx + 1; j < n_bitrates; j++) {
470 		if (mask & (1 << j)) {
471 			/* Okay, found a suitable rate. Use it. */
472 			*rate_idx = j;
473 			return true;
474 		}
475 	}
476 	return false;
477 }
478 
479 static bool rate_idx_match_mcs_mask(s8 *rate_idx, u8 *mcs_mask)
480 {
481 	int i, j;
482 	int ridx, rbit;
483 
484 	ridx = *rate_idx / 8;
485 	rbit = *rate_idx % 8;
486 
487 	/* sanity check */
488 	if (ridx < 0 || ridx >= IEEE80211_HT_MCS_MASK_LEN)
489 		return false;
490 
491 	/* See whether the selected rate or anything below it is allowed. */
492 	for (i = ridx; i >= 0; i--) {
493 		for (j = rbit; j >= 0; j--)
494 			if (mcs_mask[i] & BIT(j)) {
495 				*rate_idx = i * 8 + j;
496 				return true;
497 			}
498 		rbit = 7;
499 	}
500 
501 	/* Try to find a higher rate that would be allowed */
502 	ridx = (*rate_idx + 1) / 8;
503 	rbit = (*rate_idx + 1) % 8;
504 
505 	for (i = ridx; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
506 		for (j = rbit; j < 8; j++)
507 			if (mcs_mask[i] & BIT(j)) {
508 				*rate_idx = i * 8 + j;
509 				return true;
510 			}
511 		rbit = 0;
512 	}
513 	return false;
514 }
515 
516 static bool rate_idx_match_vht_mcs_mask(s8 *rate_idx, u16 *vht_mask)
517 {
518 	int i, j;
519 	int ridx, rbit;
520 
521 	ridx = *rate_idx >> 4;
522 	rbit = *rate_idx & 0xf;
523 
524 	if (ridx < 0 || ridx >= NL80211_VHT_NSS_MAX)
525 		return false;
526 
527 	/* See whether the selected rate or anything below it is allowed. */
528 	for (i = ridx; i >= 0; i--) {
529 		for (j = rbit; j >= 0; j--) {
530 			if (vht_mask[i] & BIT(j)) {
531 				*rate_idx = (i << 4) | j;
532 				return true;
533 			}
534 		}
535 		rbit = 15;
536 	}
537 
538 	/* Try to find a higher rate that would be allowed */
539 	ridx = (*rate_idx + 1) >> 4;
540 	rbit = (*rate_idx + 1) & 0xf;
541 
542 	for (i = ridx; i < NL80211_VHT_NSS_MAX; i++) {
543 		for (j = rbit; j < 16; j++) {
544 			if (vht_mask[i] & BIT(j)) {
545 				*rate_idx = (i << 4) | j;
546 				return true;
547 			}
548 		}
549 		rbit = 0;
550 	}
551 	return false;
552 }
553 
554 static void rate_idx_match_mask(s8 *rate_idx, u16 *rate_flags,
555 				struct ieee80211_supported_band *sband,
556 				enum nl80211_chan_width chan_width,
557 				u32 mask,
558 				u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN],
559 				u16 vht_mask[NL80211_VHT_NSS_MAX])
560 {
561 	if (*rate_flags & IEEE80211_TX_RC_VHT_MCS) {
562 		/* handle VHT rates */
563 		if (rate_idx_match_vht_mcs_mask(rate_idx, vht_mask))
564 			return;
565 
566 		*rate_idx = 0;
567 		/* keep protection flags */
568 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
569 				IEEE80211_TX_RC_USE_CTS_PROTECT |
570 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
571 
572 		*rate_flags |= IEEE80211_TX_RC_MCS;
573 		if (chan_width == NL80211_CHAN_WIDTH_40)
574 			*rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
575 
576 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
577 			return;
578 
579 		/* also try the legacy rates. */
580 		*rate_flags &= ~(IEEE80211_TX_RC_MCS |
581 				 IEEE80211_TX_RC_40_MHZ_WIDTH);
582 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
583 					       mask))
584 			return;
585 	} else if (*rate_flags & IEEE80211_TX_RC_MCS) {
586 		/* handle HT rates */
587 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
588 			return;
589 
590 		/* also try the legacy rates. */
591 		*rate_idx = 0;
592 		/* keep protection flags */
593 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
594 				IEEE80211_TX_RC_USE_CTS_PROTECT |
595 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
596 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
597 					       mask))
598 			return;
599 	} else {
600 		/* handle legacy rates */
601 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
602 					       mask))
603 			return;
604 
605 		/* if HT BSS, and we handle a data frame, also try HT rates */
606 		switch (chan_width) {
607 		case NL80211_CHAN_WIDTH_20_NOHT:
608 		case NL80211_CHAN_WIDTH_5:
609 		case NL80211_CHAN_WIDTH_10:
610 			return;
611 		default:
612 			break;
613 		}
614 
615 		*rate_idx = 0;
616 		/* keep protection flags */
617 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
618 				IEEE80211_TX_RC_USE_CTS_PROTECT |
619 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
620 
621 		*rate_flags |= IEEE80211_TX_RC_MCS;
622 
623 		if (chan_width == NL80211_CHAN_WIDTH_40)
624 			*rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
625 
626 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
627 			return;
628 	}
629 
630 	/*
631 	 * Uh.. No suitable rate exists. This should not really happen with
632 	 * sane TX rate mask configurations. However, should someone manage to
633 	 * configure supported rates and TX rate mask in incompatible way,
634 	 * allow the frame to be transmitted with whatever the rate control
635 	 * selected.
636 	 */
637 }
638 
639 static void rate_fixup_ratelist(struct ieee80211_vif *vif,
640 				struct ieee80211_supported_band *sband,
641 				struct ieee80211_tx_info *info,
642 				struct ieee80211_tx_rate *rates,
643 				int max_rates)
644 {
645 	struct ieee80211_rate *rate;
646 	bool inval = false;
647 	int i;
648 
649 	/*
650 	 * Set up the RTS/CTS rate as the fastest basic rate
651 	 * that is not faster than the data rate unless there
652 	 * is no basic rate slower than the data rate, in which
653 	 * case we pick the slowest basic rate
654 	 *
655 	 * XXX: Should this check all retry rates?
656 	 */
657 	if (!(rates[0].flags &
658 	      (IEEE80211_TX_RC_MCS | IEEE80211_TX_RC_VHT_MCS))) {
659 		u32 basic_rates = vif->bss_conf.basic_rates;
660 		s8 baserate = basic_rates ? ffs(basic_rates) - 1 : 0;
661 
662 		rate = &sband->bitrates[rates[0].idx];
663 
664 		for (i = 0; i < sband->n_bitrates; i++) {
665 			/* must be a basic rate */
666 			if (!(basic_rates & BIT(i)))
667 				continue;
668 			/* must not be faster than the data rate */
669 			if (sband->bitrates[i].bitrate > rate->bitrate)
670 				continue;
671 			/* maximum */
672 			if (sband->bitrates[baserate].bitrate <
673 			     sband->bitrates[i].bitrate)
674 				baserate = i;
675 		}
676 
677 		info->control.rts_cts_rate_idx = baserate;
678 	}
679 
680 	for (i = 0; i < max_rates; i++) {
681 		/*
682 		 * make sure there's no valid rate following
683 		 * an invalid one, just in case drivers don't
684 		 * take the API seriously to stop at -1.
685 		 */
686 		if (inval) {
687 			rates[i].idx = -1;
688 			continue;
689 		}
690 		if (rates[i].idx < 0) {
691 			inval = true;
692 			continue;
693 		}
694 
695 		/*
696 		 * For now assume MCS is already set up correctly, this
697 		 * needs to be fixed.
698 		 */
699 		if (rates[i].flags & IEEE80211_TX_RC_MCS) {
700 			WARN_ON(rates[i].idx > 76);
701 
702 			if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
703 			    info->control.use_cts_prot)
704 				rates[i].flags |=
705 					IEEE80211_TX_RC_USE_CTS_PROTECT;
706 			continue;
707 		}
708 
709 		if (rates[i].flags & IEEE80211_TX_RC_VHT_MCS) {
710 			WARN_ON(ieee80211_rate_get_vht_mcs(&rates[i]) > 9);
711 			continue;
712 		}
713 
714 		/* set up RTS protection if desired */
715 		if (info->control.use_rts) {
716 			rates[i].flags |= IEEE80211_TX_RC_USE_RTS_CTS;
717 			info->control.use_cts_prot = false;
718 		}
719 
720 		/* RC is busted */
721 		if (WARN_ON_ONCE(rates[i].idx >= sband->n_bitrates)) {
722 			rates[i].idx = -1;
723 			continue;
724 		}
725 
726 		rate = &sband->bitrates[rates[i].idx];
727 
728 		/* set up short preamble */
729 		if (info->control.short_preamble &&
730 		    rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
731 			rates[i].flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
732 
733 		/* set up G protection */
734 		if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
735 		    info->control.use_cts_prot &&
736 		    rate->flags & IEEE80211_RATE_ERP_G)
737 			rates[i].flags |= IEEE80211_TX_RC_USE_CTS_PROTECT;
738 	}
739 }
740 
741 
742 static void rate_control_fill_sta_table(struct ieee80211_sta *sta,
743 					struct ieee80211_tx_info *info,
744 					struct ieee80211_tx_rate *rates,
745 					int max_rates)
746 {
747 	struct ieee80211_sta_rates *ratetbl = NULL;
748 	int i;
749 
750 	if (sta && !info->control.skip_table)
751 		ratetbl = rcu_dereference(sta->rates);
752 
753 	/* Fill remaining rate slots with data from the sta rate table. */
754 	max_rates = min_t(int, max_rates, IEEE80211_TX_RATE_TABLE_SIZE);
755 	for (i = 0; i < max_rates; i++) {
756 		if (i < ARRAY_SIZE(info->control.rates) &&
757 		    info->control.rates[i].idx >= 0 &&
758 		    info->control.rates[i].count) {
759 			if (rates != info->control.rates)
760 				rates[i] = info->control.rates[i];
761 		} else if (ratetbl) {
762 			rates[i].idx = ratetbl->rate[i].idx;
763 			rates[i].flags = ratetbl->rate[i].flags;
764 			if (info->control.use_rts)
765 				rates[i].count = ratetbl->rate[i].count_rts;
766 			else if (info->control.use_cts_prot)
767 				rates[i].count = ratetbl->rate[i].count_cts;
768 			else
769 				rates[i].count = ratetbl->rate[i].count;
770 		} else {
771 			rates[i].idx = -1;
772 			rates[i].count = 0;
773 		}
774 
775 		if (rates[i].idx < 0 || !rates[i].count)
776 			break;
777 	}
778 }
779 
780 static bool rate_control_cap_mask(struct ieee80211_sub_if_data *sdata,
781 				  struct ieee80211_supported_band *sband,
782 				  struct ieee80211_sta *sta, u32 *mask,
783 				  u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN],
784 				  u16 vht_mask[NL80211_VHT_NSS_MAX])
785 {
786 	u32 i;
787 
788 	*mask = sdata->rc_rateidx_mask[sband->band];
789 
790 	if (*mask == (1 << sband->n_bitrates) - 1 &&
791 	    !sdata->rc_has_mcs_mask[sband->band] &&
792 	    !sdata->rc_has_vht_mcs_mask[sband->band])
793 		return false;
794 
795 	if (sdata->rc_has_mcs_mask[sband->band])
796 		memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[sband->band],
797 		       IEEE80211_HT_MCS_MASK_LEN);
798 	else
799 		memset(mcs_mask, 0xff, IEEE80211_HT_MCS_MASK_LEN);
800 
801 	if (sdata->rc_has_vht_mcs_mask[sband->band])
802 		memcpy(vht_mask, sdata->rc_rateidx_vht_mcs_mask[sband->band],
803 		       sizeof(u16) * NL80211_VHT_NSS_MAX);
804 	else
805 		memset(vht_mask, 0xff, sizeof(u16) * NL80211_VHT_NSS_MAX);
806 
807 	if (sta) {
808 		__le16 sta_vht_cap;
809 		u16 sta_vht_mask[NL80211_VHT_NSS_MAX];
810 
811 		/* Filter out rates that the STA does not support */
812 		*mask &= sta->deflink.supp_rates[sband->band];
813 		for (i = 0; i < IEEE80211_HT_MCS_MASK_LEN; i++)
814 			mcs_mask[i] &= sta->deflink.ht_cap.mcs.rx_mask[i];
815 
816 		sta_vht_cap = sta->deflink.vht_cap.vht_mcs.rx_mcs_map;
817 		ieee80211_get_vht_mask_from_cap(sta_vht_cap, sta_vht_mask);
818 		for (i = 0; i < NL80211_VHT_NSS_MAX; i++)
819 			vht_mask[i] &= sta_vht_mask[i];
820 	}
821 
822 	return true;
823 }
824 
825 static void
826 rate_control_apply_mask_ratetbl(struct sta_info *sta,
827 				struct ieee80211_supported_band *sband,
828 				struct ieee80211_sta_rates *rates)
829 {
830 	int i;
831 	u32 mask;
832 	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
833 	u16 vht_mask[NL80211_VHT_NSS_MAX];
834 	enum nl80211_chan_width chan_width;
835 
836 	if (!rate_control_cap_mask(sta->sdata, sband, &sta->sta, &mask,
837 				   mcs_mask, vht_mask))
838 		return;
839 
840 	chan_width = sta->sdata->vif.bss_conf.chanreq.oper.width;
841 	for (i = 0; i < IEEE80211_TX_RATE_TABLE_SIZE; i++) {
842 		if (rates->rate[i].idx < 0)
843 			break;
844 
845 		rate_idx_match_mask(&rates->rate[i].idx, &rates->rate[i].flags,
846 				    sband, chan_width, mask, mcs_mask,
847 				    vht_mask);
848 	}
849 }
850 
851 static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
852 				    struct ieee80211_sta *sta,
853 				    struct ieee80211_supported_band *sband,
854 				    struct ieee80211_tx_rate *rates,
855 				    int max_rates)
856 {
857 	enum nl80211_chan_width chan_width;
858 	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
859 	u32 mask;
860 	u16 rate_flags, vht_mask[NL80211_VHT_NSS_MAX];
861 	int i;
862 
863 	/*
864 	 * Try to enforce the rateidx mask the user wanted. skip this if the
865 	 * default mask (allow all rates) is used to save some processing for
866 	 * the common case.
867 	 */
868 	if (!rate_control_cap_mask(sdata, sband, sta, &mask, mcs_mask,
869 				   vht_mask))
870 		return;
871 
872 	/*
873 	 * Make sure the rate index selected for each TX rate is
874 	 * included in the configured mask and change the rate indexes
875 	 * if needed.
876 	 */
877 	chan_width = sdata->vif.bss_conf.chanreq.oper.width;
878 	for (i = 0; i < max_rates; i++) {
879 		/* Skip invalid rates */
880 		if (rates[i].idx < 0)
881 			break;
882 
883 		rate_flags = rates[i].flags;
884 		rate_idx_match_mask(&rates[i].idx, &rate_flags, sband,
885 				    chan_width, mask, mcs_mask, vht_mask);
886 		rates[i].flags = rate_flags;
887 	}
888 }
889 
890 void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
891 			    struct ieee80211_sta *sta,
892 			    struct sk_buff *skb,
893 			    struct ieee80211_tx_rate *dest,
894 			    int max_rates)
895 {
896 	struct ieee80211_sub_if_data *sdata;
897 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
898 	struct ieee80211_supported_band *sband;
899 	u32 mask = ~0;
900 
901 	rate_control_fill_sta_table(sta, info, dest, max_rates);
902 
903 	if (!vif)
904 		return;
905 
906 	sdata = vif_to_sdata(vif);
907 	if (info->band >= NUM_NL80211_BANDS)
908 		return;
909 
910 	sband = sdata->local->hw.wiphy->bands[info->band];
911 
912 	if (ieee80211_is_tx_data(skb))
913 		rate_control_apply_mask(sdata, sta, sband, dest, max_rates);
914 
915 	if (!(info->control.flags & IEEE80211_TX_CTRL_DONT_USE_RATE_MASK))
916 		mask = sdata->rc_rateidx_mask[info->band];
917 
918 	if (dest[0].idx < 0)
919 		__rate_control_send_low(&sdata->local->hw, sband, sta, info,
920 					mask);
921 
922 	if (sta)
923 		rate_fixup_ratelist(vif, sband, info, dest, max_rates);
924 }
925 EXPORT_SYMBOL(ieee80211_get_tx_rates);
926 
927 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
928 			   struct sta_info *sta,
929 			   struct ieee80211_tx_rate_control *txrc)
930 {
931 	struct rate_control_ref *ref = sdata->local->rate_ctrl;
932 	void *priv_sta = NULL;
933 	struct ieee80211_sta *ista = NULL;
934 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
935 	int i;
936 
937 	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
938 		info->control.rates[i].idx = -1;
939 		info->control.rates[i].flags = 0;
940 		info->control.rates[i].count = 0;
941 	}
942 
943 	if (rate_control_send_low(sta ? &sta->sta : NULL, txrc))
944 		return;
945 
946 	if (ieee80211_hw_check(&sdata->local->hw, HAS_RATE_CONTROL))
947 		return;
948 
949 	if (sta && test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) {
950 		ista = &sta->sta;
951 		priv_sta = sta->rate_ctrl_priv;
952 	}
953 
954 	if (ista) {
955 		spin_lock_bh(&sta->rate_ctrl_lock);
956 		ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
957 		spin_unlock_bh(&sta->rate_ctrl_lock);
958 	} else {
959 		rate_control_send_low(NULL, txrc);
960 	}
961 
962 	if (ieee80211_hw_check(&sdata->local->hw, SUPPORTS_RC_TABLE))
963 		return;
964 
965 	ieee80211_get_tx_rates(&sdata->vif, ista, txrc->skb,
966 			       info->control.rates,
967 			       ARRAY_SIZE(info->control.rates));
968 }
969 
970 int rate_control_set_rates(struct ieee80211_hw *hw,
971 			   struct ieee80211_sta *pubsta,
972 			   struct ieee80211_sta_rates *rates)
973 {
974 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
975 	struct ieee80211_sta_rates *old;
976 	struct ieee80211_supported_band *sband;
977 
978 	sband = ieee80211_get_sband(sta->sdata);
979 	if (!sband)
980 		return -EINVAL;
981 	rate_control_apply_mask_ratetbl(sta, sband, rates);
982 	/*
983 	 * mac80211 guarantees that this function will not be called
984 	 * concurrently, so the following RCU access is safe, even without
985 	 * extra locking. This can not be checked easily, so we just set
986 	 * the condition to true.
987 	 */
988 	old = rcu_dereference_protected(pubsta->rates, true);
989 	rcu_assign_pointer(pubsta->rates, rates);
990 	if (old)
991 		kfree_rcu(old, rcu_head);
992 
993 	if (sta->uploaded)
994 		drv_sta_rate_tbl_update(hw_to_local(hw), sta->sdata, pubsta);
995 
996 	return 0;
997 }
998 EXPORT_SYMBOL(rate_control_set_rates);
999 
1000 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
1001 				 const char *name)
1002 {
1003 	struct rate_control_ref *ref;
1004 
1005 	ASSERT_RTNL();
1006 
1007 	if (local->open_count)
1008 		return -EBUSY;
1009 
1010 	if (ieee80211_hw_check(&local->hw, HAS_RATE_CONTROL)) {
1011 		if (WARN_ON(!local->ops->set_rts_threshold))
1012 			return -EINVAL;
1013 		return 0;
1014 	}
1015 
1016 	ref = rate_control_alloc(name, local);
1017 	if (!ref) {
1018 		wiphy_warn(local->hw.wiphy,
1019 			   "Failed to select rate control algorithm\n");
1020 		return -ENOENT;
1021 	}
1022 
1023 	WARN_ON(local->rate_ctrl);
1024 	local->rate_ctrl = ref;
1025 
1026 	wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n",
1027 		    ref->ops->name);
1028 
1029 	return 0;
1030 }
1031 
1032 void rate_control_deinitialize(struct ieee80211_local *local)
1033 {
1034 	struct rate_control_ref *ref;
1035 
1036 	ref = local->rate_ctrl;
1037 
1038 	if (!ref)
1039 		return;
1040 
1041 	local->rate_ctrl = NULL;
1042 	rate_control_free(local, ref);
1043 }
1044