xref: /linux/net/mac80211/rate.c (revision 2c7b9b936bdc6ff0a7a5f6aed8e55d27ca14807d)
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) 2022 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 sta_info *sta)
32 {
33 	struct ieee80211_local *local = sta->sdata->local;
34 	struct rate_control_ref *ref = sta->rate_ctrl;
35 	struct ieee80211_sta *ista = &sta->sta;
36 	void *priv_sta = sta->rate_ctrl_priv;
37 	struct ieee80211_supported_band *sband;
38 	struct ieee80211_chanctx_conf *chanctx_conf;
39 
40 	ieee80211_sta_set_rx_nss(&sta->deflink);
41 
42 	if (!ref)
43 		return;
44 
45 	rcu_read_lock();
46 
47 	chanctx_conf = rcu_dereference(sta->sdata->vif.bss_conf.chanctx_conf);
48 	if (WARN_ON(!chanctx_conf)) {
49 		rcu_read_unlock();
50 		return;
51 	}
52 
53 	sband = local->hw.wiphy->bands[chanctx_conf->def.chan->band];
54 
55 	/* TODO: check for minstrel_s1g ? */
56 	if (sband->band == NL80211_BAND_S1GHZ) {
57 		ieee80211_s1g_sta_rate_init(sta);
58 		rcu_read_unlock();
59 		return;
60 	}
61 
62 	spin_lock_bh(&sta->rate_ctrl_lock);
63 	ref->ops->rate_init(ref->priv, sband, &chanctx_conf->def, ista,
64 			    priv_sta);
65 	spin_unlock_bh(&sta->rate_ctrl_lock);
66 	rcu_read_unlock();
67 	set_sta_flag(sta, WLAN_STA_RATE_CONTROL);
68 }
69 
70 void rate_control_tx_status(struct ieee80211_local *local,
71 			    struct ieee80211_tx_status *st)
72 {
73 	struct rate_control_ref *ref = local->rate_ctrl;
74 	struct sta_info *sta = container_of(st->sta, struct sta_info, sta);
75 	void *priv_sta = sta->rate_ctrl_priv;
76 	struct ieee80211_supported_band *sband;
77 
78 	if (!ref || !test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
79 		return;
80 
81 	sband = local->hw.wiphy->bands[st->info->band];
82 
83 	spin_lock_bh(&sta->rate_ctrl_lock);
84 	if (ref->ops->tx_status_ext)
85 		ref->ops->tx_status_ext(ref->priv, sband, priv_sta, st);
86 	else if (st->skb)
87 		ref->ops->tx_status(ref->priv, sband, st->sta, priv_sta, st->skb);
88 	else
89 		WARN_ON_ONCE(1);
90 
91 	spin_unlock_bh(&sta->rate_ctrl_lock);
92 }
93 
94 void rate_control_rate_update(struct ieee80211_local *local,
95 			      struct ieee80211_supported_band *sband,
96 			      struct sta_info *sta, unsigned int link_id,
97 			      u32 changed)
98 {
99 	struct rate_control_ref *ref = local->rate_ctrl;
100 	struct ieee80211_sta *ista = &sta->sta;
101 	void *priv_sta = sta->rate_ctrl_priv;
102 	struct ieee80211_chanctx_conf *chanctx_conf;
103 
104 	WARN_ON(link_id != 0);
105 
106 	if (ref && ref->ops->rate_update) {
107 		rcu_read_lock();
108 
109 		chanctx_conf = rcu_dereference(sta->sdata->vif.bss_conf.chanctx_conf);
110 		if (WARN_ON(!chanctx_conf)) {
111 			rcu_read_unlock();
112 			return;
113 		}
114 
115 		spin_lock_bh(&sta->rate_ctrl_lock);
116 		ref->ops->rate_update(ref->priv, sband, &chanctx_conf->def,
117 				      ista, priv_sta, changed);
118 		spin_unlock_bh(&sta->rate_ctrl_lock);
119 		rcu_read_unlock();
120 	}
121 
122 	drv_sta_rc_update(local, sta->sdata, &sta->sta, changed);
123 }
124 
125 int ieee80211_rate_control_register(const struct rate_control_ops *ops)
126 {
127 	struct rate_control_alg *alg;
128 
129 	if (!ops->name)
130 		return -EINVAL;
131 
132 	mutex_lock(&rate_ctrl_mutex);
133 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
134 		if (!strcmp(alg->ops->name, ops->name)) {
135 			/* don't register an algorithm twice */
136 			WARN_ON(1);
137 			mutex_unlock(&rate_ctrl_mutex);
138 			return -EALREADY;
139 		}
140 	}
141 
142 	alg = kzalloc(sizeof(*alg), GFP_KERNEL);
143 	if (alg == NULL) {
144 		mutex_unlock(&rate_ctrl_mutex);
145 		return -ENOMEM;
146 	}
147 	alg->ops = ops;
148 
149 	list_add_tail(&alg->list, &rate_ctrl_algs);
150 	mutex_unlock(&rate_ctrl_mutex);
151 
152 	return 0;
153 }
154 EXPORT_SYMBOL(ieee80211_rate_control_register);
155 
156 void ieee80211_rate_control_unregister(const struct rate_control_ops *ops)
157 {
158 	struct rate_control_alg *alg;
159 
160 	mutex_lock(&rate_ctrl_mutex);
161 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
162 		if (alg->ops == ops) {
163 			list_del(&alg->list);
164 			kfree(alg);
165 			break;
166 		}
167 	}
168 	mutex_unlock(&rate_ctrl_mutex);
169 }
170 EXPORT_SYMBOL(ieee80211_rate_control_unregister);
171 
172 static const struct rate_control_ops *
173 ieee80211_try_rate_control_ops_get(const char *name)
174 {
175 	struct rate_control_alg *alg;
176 	const struct rate_control_ops *ops = NULL;
177 
178 	if (!name)
179 		return NULL;
180 
181 	mutex_lock(&rate_ctrl_mutex);
182 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
183 		if (!strcmp(alg->ops->name, name)) {
184 			ops = alg->ops;
185 			break;
186 		}
187 	}
188 	mutex_unlock(&rate_ctrl_mutex);
189 	return ops;
190 }
191 
192 /* Get the rate control algorithm. */
193 static const struct rate_control_ops *
194 ieee80211_rate_control_ops_get(const char *name)
195 {
196 	const struct rate_control_ops *ops;
197 	const char *alg_name;
198 
199 	kernel_param_lock(THIS_MODULE);
200 	if (!name)
201 		alg_name = ieee80211_default_rc_algo;
202 	else
203 		alg_name = name;
204 
205 	ops = ieee80211_try_rate_control_ops_get(alg_name);
206 	if (!ops && name)
207 		/* try default if specific alg requested but not found */
208 		ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);
209 
210 	/* Note: check for > 0 is intentional to avoid clang warning */
211 	if (!ops && (strlen(CONFIG_MAC80211_RC_DEFAULT) > 0))
212 		/* try built-in one if specific alg requested but not found */
213 		ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
214 
215 	kernel_param_unlock(THIS_MODULE);
216 
217 	return ops;
218 }
219 
220 #ifdef CONFIG_MAC80211_DEBUGFS
221 static ssize_t rcname_read(struct file *file, char __user *userbuf,
222 			   size_t count, loff_t *ppos)
223 {
224 	struct rate_control_ref *ref = file->private_data;
225 	int len = strlen(ref->ops->name);
226 
227 	return simple_read_from_buffer(userbuf, count, ppos,
228 				       ref->ops->name, len);
229 }
230 
231 const struct file_operations rcname_ops = {
232 	.read = rcname_read,
233 	.open = simple_open,
234 	.llseek = default_llseek,
235 };
236 #endif
237 
238 static struct rate_control_ref *
239 rate_control_alloc(const char *name, struct ieee80211_local *local)
240 {
241 	struct rate_control_ref *ref;
242 
243 	ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
244 	if (!ref)
245 		return NULL;
246 	ref->ops = ieee80211_rate_control_ops_get(name);
247 	if (!ref->ops)
248 		goto free;
249 
250 	ref->priv = ref->ops->alloc(&local->hw);
251 	if (!ref->priv)
252 		goto free;
253 	return ref;
254 
255 free:
256 	kfree(ref);
257 	return NULL;
258 }
259 
260 static void rate_control_free(struct ieee80211_local *local,
261 			      struct rate_control_ref *ctrl_ref)
262 {
263 	ctrl_ref->ops->free(ctrl_ref->priv);
264 
265 #ifdef CONFIG_MAC80211_DEBUGFS
266 	debugfs_remove_recursive(local->debugfs.rcdir);
267 	local->debugfs.rcdir = NULL;
268 #endif
269 
270 	kfree(ctrl_ref);
271 }
272 
273 void ieee80211_check_rate_mask(struct ieee80211_sub_if_data *sdata)
274 {
275 	struct ieee80211_local *local = sdata->local;
276 	struct ieee80211_supported_band *sband;
277 	u32 user_mask, basic_rates = sdata->vif.bss_conf.basic_rates;
278 	enum nl80211_band band;
279 
280 	if (WARN_ON(!sdata->vif.bss_conf.chandef.chan))
281 		return;
282 
283 	band = sdata->vif.bss_conf.chandef.chan->band;
284 	if (band == NL80211_BAND_S1GHZ) {
285 		/* TODO */
286 		return;
287 	}
288 
289 	if (WARN_ON_ONCE(!basic_rates))
290 		return;
291 
292 	user_mask = sdata->rc_rateidx_mask[band];
293 	sband = local->hw.wiphy->bands[band];
294 
295 	if (user_mask & basic_rates)
296 		return;
297 
298 	sdata_dbg(sdata,
299 		  "no overlap between basic rates (0x%x) and user mask (0x%x on band %d) - clearing the latter",
300 		  basic_rates, user_mask, band);
301 	sdata->rc_rateidx_mask[band] = (1 << sband->n_bitrates) - 1;
302 }
303 
304 static bool rc_no_data_or_no_ack_use_min(struct ieee80211_tx_rate_control *txrc)
305 {
306 	struct sk_buff *skb = txrc->skb;
307 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
308 
309 	return (info->flags & (IEEE80211_TX_CTL_NO_ACK |
310 			       IEEE80211_TX_CTL_USE_MINRATE)) ||
311 		!ieee80211_is_tx_data(skb);
312 }
313 
314 static void rc_send_low_basicrate(struct ieee80211_tx_rate *rate,
315 				  u32 basic_rates,
316 				  struct ieee80211_supported_band *sband)
317 {
318 	u8 i;
319 
320 	if (sband->band == NL80211_BAND_S1GHZ) {
321 		/* TODO */
322 		rate->flags |= IEEE80211_TX_RC_S1G_MCS;
323 		rate->idx = 0;
324 		return;
325 	}
326 
327 	if (basic_rates == 0)
328 		return; /* assume basic rates unknown and accept rate */
329 	if (rate->idx < 0)
330 		return;
331 	if (basic_rates & (1 << rate->idx))
332 		return; /* selected rate is a basic rate */
333 
334 	for (i = rate->idx + 1; i <= sband->n_bitrates; i++) {
335 		if (basic_rates & (1 << i)) {
336 			rate->idx = i;
337 			return;
338 		}
339 	}
340 
341 	/* could not find a basic rate; use original selection */
342 }
343 
344 static void __rate_control_send_low(struct ieee80211_hw *hw,
345 				    struct ieee80211_supported_band *sband,
346 				    struct ieee80211_sta *sta,
347 				    struct ieee80211_tx_info *info,
348 				    u32 rate_mask)
349 {
350 	int i;
351 	u32 rate_flags =
352 		ieee80211_chandef_rate_flags(&hw->conf.chandef);
353 
354 	if (sband->band == NL80211_BAND_S1GHZ) {
355 		info->control.rates[0].flags |= IEEE80211_TX_RC_S1G_MCS;
356 		info->control.rates[0].idx = 0;
357 		return;
358 	}
359 
360 	if ((sband->band == NL80211_BAND_2GHZ) &&
361 	    (info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
362 		rate_flags |= IEEE80211_RATE_ERP_G;
363 
364 	info->control.rates[0].idx = 0;
365 	for (i = 0; i < sband->n_bitrates; i++) {
366 		if (!(rate_mask & BIT(i)))
367 			continue;
368 
369 		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
370 			continue;
371 
372 		if (!rate_supported(sta, sband->band, i))
373 			continue;
374 
375 		info->control.rates[0].idx = i;
376 		break;
377 	}
378 	WARN_ONCE(i == sband->n_bitrates,
379 		  "no supported rates for sta %pM (0x%x, band %d) in rate_mask 0x%x with flags 0x%x\n",
380 		  sta ? sta->addr : NULL,
381 		  sta ? sta->deflink.supp_rates[sband->band] : -1,
382 		  sband->band,
383 		  rate_mask, rate_flags);
384 
385 	info->control.rates[0].count =
386 		(info->flags & IEEE80211_TX_CTL_NO_ACK) ?
387 		1 : hw->max_rate_tries;
388 
389 	info->control.skip_table = 1;
390 }
391 
392 
393 static bool rate_control_send_low(struct ieee80211_sta *pubsta,
394 				  struct ieee80211_tx_rate_control *txrc)
395 {
396 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
397 	struct ieee80211_supported_band *sband = txrc->sband;
398 	struct sta_info *sta;
399 	int mcast_rate;
400 	bool use_basicrate = false;
401 
402 	if (!pubsta || rc_no_data_or_no_ack_use_min(txrc)) {
403 		__rate_control_send_low(txrc->hw, sband, pubsta, info,
404 					txrc->rate_idx_mask);
405 
406 		if (!pubsta && txrc->bss) {
407 			mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
408 			if (mcast_rate > 0) {
409 				info->control.rates[0].idx = mcast_rate - 1;
410 				return true;
411 			}
412 			use_basicrate = true;
413 		} else if (pubsta) {
414 			sta = container_of(pubsta, struct sta_info, sta);
415 			if (ieee80211_vif_is_mesh(&sta->sdata->vif))
416 				use_basicrate = true;
417 		}
418 
419 		if (use_basicrate)
420 			rc_send_low_basicrate(&info->control.rates[0],
421 					      txrc->bss_conf->basic_rates,
422 					      sband);
423 
424 		return true;
425 	}
426 	return false;
427 }
428 
429 static bool rate_idx_match_legacy_mask(s8 *rate_idx, int n_bitrates, u32 mask)
430 {
431 	int j;
432 
433 	/* See whether the selected rate or anything below it is allowed. */
434 	for (j = *rate_idx; j >= 0; j--) {
435 		if (mask & (1 << j)) {
436 			/* Okay, found a suitable rate. Use it. */
437 			*rate_idx = j;
438 			return true;
439 		}
440 	}
441 
442 	/* Try to find a higher rate that would be allowed */
443 	for (j = *rate_idx + 1; j < n_bitrates; j++) {
444 		if (mask & (1 << j)) {
445 			/* Okay, found a suitable rate. Use it. */
446 			*rate_idx = j;
447 			return true;
448 		}
449 	}
450 	return false;
451 }
452 
453 static bool rate_idx_match_mcs_mask(s8 *rate_idx, u8 *mcs_mask)
454 {
455 	int i, j;
456 	int ridx, rbit;
457 
458 	ridx = *rate_idx / 8;
459 	rbit = *rate_idx % 8;
460 
461 	/* sanity check */
462 	if (ridx < 0 || ridx >= IEEE80211_HT_MCS_MASK_LEN)
463 		return false;
464 
465 	/* See whether the selected rate or anything below it is allowed. */
466 	for (i = ridx; i >= 0; i--) {
467 		for (j = rbit; j >= 0; j--)
468 			if (mcs_mask[i] & BIT(j)) {
469 				*rate_idx = i * 8 + j;
470 				return true;
471 			}
472 		rbit = 7;
473 	}
474 
475 	/* Try to find a higher rate that would be allowed */
476 	ridx = (*rate_idx + 1) / 8;
477 	rbit = (*rate_idx + 1) % 8;
478 
479 	for (i = ridx; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
480 		for (j = rbit; j < 8; j++)
481 			if (mcs_mask[i] & BIT(j)) {
482 				*rate_idx = i * 8 + j;
483 				return true;
484 			}
485 		rbit = 0;
486 	}
487 	return false;
488 }
489 
490 static bool rate_idx_match_vht_mcs_mask(s8 *rate_idx, u16 *vht_mask)
491 {
492 	int i, j;
493 	int ridx, rbit;
494 
495 	ridx = *rate_idx >> 4;
496 	rbit = *rate_idx & 0xf;
497 
498 	if (ridx < 0 || ridx >= NL80211_VHT_NSS_MAX)
499 		return false;
500 
501 	/* See whether the selected rate or anything below it is allowed. */
502 	for (i = ridx; i >= 0; i--) {
503 		for (j = rbit; j >= 0; j--) {
504 			if (vht_mask[i] & BIT(j)) {
505 				*rate_idx = (i << 4) | j;
506 				return true;
507 			}
508 		}
509 		rbit = 15;
510 	}
511 
512 	/* Try to find a higher rate that would be allowed */
513 	ridx = (*rate_idx + 1) >> 4;
514 	rbit = (*rate_idx + 1) & 0xf;
515 
516 	for (i = ridx; i < NL80211_VHT_NSS_MAX; i++) {
517 		for (j = rbit; j < 16; j++) {
518 			if (vht_mask[i] & BIT(j)) {
519 				*rate_idx = (i << 4) | j;
520 				return true;
521 			}
522 		}
523 		rbit = 0;
524 	}
525 	return false;
526 }
527 
528 static void rate_idx_match_mask(s8 *rate_idx, u16 *rate_flags,
529 				struct ieee80211_supported_band *sband,
530 				enum nl80211_chan_width chan_width,
531 				u32 mask,
532 				u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN],
533 				u16 vht_mask[NL80211_VHT_NSS_MAX])
534 {
535 	if (*rate_flags & IEEE80211_TX_RC_VHT_MCS) {
536 		/* handle VHT rates */
537 		if (rate_idx_match_vht_mcs_mask(rate_idx, vht_mask))
538 			return;
539 
540 		*rate_idx = 0;
541 		/* keep protection flags */
542 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
543 				IEEE80211_TX_RC_USE_CTS_PROTECT |
544 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
545 
546 		*rate_flags |= IEEE80211_TX_RC_MCS;
547 		if (chan_width == NL80211_CHAN_WIDTH_40)
548 			*rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
549 
550 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
551 			return;
552 
553 		/* also try the legacy rates. */
554 		*rate_flags &= ~(IEEE80211_TX_RC_MCS |
555 				 IEEE80211_TX_RC_40_MHZ_WIDTH);
556 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
557 					       mask))
558 			return;
559 	} else if (*rate_flags & IEEE80211_TX_RC_MCS) {
560 		/* handle HT rates */
561 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
562 			return;
563 
564 		/* also try the legacy rates. */
565 		*rate_idx = 0;
566 		/* keep protection flags */
567 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
568 				IEEE80211_TX_RC_USE_CTS_PROTECT |
569 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
570 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
571 					       mask))
572 			return;
573 	} else {
574 		/* handle legacy rates */
575 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
576 					       mask))
577 			return;
578 
579 		/* if HT BSS, and we handle a data frame, also try HT rates */
580 		switch (chan_width) {
581 		case NL80211_CHAN_WIDTH_20_NOHT:
582 		case NL80211_CHAN_WIDTH_5:
583 		case NL80211_CHAN_WIDTH_10:
584 			return;
585 		default:
586 			break;
587 		}
588 
589 		*rate_idx = 0;
590 		/* keep protection flags */
591 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
592 				IEEE80211_TX_RC_USE_CTS_PROTECT |
593 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
594 
595 		*rate_flags |= IEEE80211_TX_RC_MCS;
596 
597 		if (chan_width == NL80211_CHAN_WIDTH_40)
598 			*rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
599 
600 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
601 			return;
602 	}
603 
604 	/*
605 	 * Uh.. No suitable rate exists. This should not really happen with
606 	 * sane TX rate mask configurations. However, should someone manage to
607 	 * configure supported rates and TX rate mask in incompatible way,
608 	 * allow the frame to be transmitted with whatever the rate control
609 	 * selected.
610 	 */
611 }
612 
613 static void rate_fixup_ratelist(struct ieee80211_vif *vif,
614 				struct ieee80211_supported_band *sband,
615 				struct ieee80211_tx_info *info,
616 				struct ieee80211_tx_rate *rates,
617 				int max_rates)
618 {
619 	struct ieee80211_rate *rate;
620 	bool inval = false;
621 	int i;
622 
623 	/*
624 	 * Set up the RTS/CTS rate as the fastest basic rate
625 	 * that is not faster than the data rate unless there
626 	 * is no basic rate slower than the data rate, in which
627 	 * case we pick the slowest basic rate
628 	 *
629 	 * XXX: Should this check all retry rates?
630 	 */
631 	if (!(rates[0].flags &
632 	      (IEEE80211_TX_RC_MCS | IEEE80211_TX_RC_VHT_MCS))) {
633 		u32 basic_rates = vif->bss_conf.basic_rates;
634 		s8 baserate = basic_rates ? ffs(basic_rates) - 1 : 0;
635 
636 		rate = &sband->bitrates[rates[0].idx];
637 
638 		for (i = 0; i < sband->n_bitrates; i++) {
639 			/* must be a basic rate */
640 			if (!(basic_rates & BIT(i)))
641 				continue;
642 			/* must not be faster than the data rate */
643 			if (sband->bitrates[i].bitrate > rate->bitrate)
644 				continue;
645 			/* maximum */
646 			if (sband->bitrates[baserate].bitrate <
647 			     sband->bitrates[i].bitrate)
648 				baserate = i;
649 		}
650 
651 		info->control.rts_cts_rate_idx = baserate;
652 	}
653 
654 	for (i = 0; i < max_rates; i++) {
655 		/*
656 		 * make sure there's no valid rate following
657 		 * an invalid one, just in case drivers don't
658 		 * take the API seriously to stop at -1.
659 		 */
660 		if (inval) {
661 			rates[i].idx = -1;
662 			continue;
663 		}
664 		if (rates[i].idx < 0) {
665 			inval = true;
666 			continue;
667 		}
668 
669 		/*
670 		 * For now assume MCS is already set up correctly, this
671 		 * needs to be fixed.
672 		 */
673 		if (rates[i].flags & IEEE80211_TX_RC_MCS) {
674 			WARN_ON(rates[i].idx > 76);
675 
676 			if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
677 			    info->control.use_cts_prot)
678 				rates[i].flags |=
679 					IEEE80211_TX_RC_USE_CTS_PROTECT;
680 			continue;
681 		}
682 
683 		if (rates[i].flags & IEEE80211_TX_RC_VHT_MCS) {
684 			WARN_ON(ieee80211_rate_get_vht_mcs(&rates[i]) > 9);
685 			continue;
686 		}
687 
688 		/* set up RTS protection if desired */
689 		if (info->control.use_rts) {
690 			rates[i].flags |= IEEE80211_TX_RC_USE_RTS_CTS;
691 			info->control.use_cts_prot = false;
692 		}
693 
694 		/* RC is busted */
695 		if (WARN_ON_ONCE(rates[i].idx >= sband->n_bitrates)) {
696 			rates[i].idx = -1;
697 			continue;
698 		}
699 
700 		rate = &sband->bitrates[rates[i].idx];
701 
702 		/* set up short preamble */
703 		if (info->control.short_preamble &&
704 		    rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
705 			rates[i].flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
706 
707 		/* set up G protection */
708 		if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
709 		    info->control.use_cts_prot &&
710 		    rate->flags & IEEE80211_RATE_ERP_G)
711 			rates[i].flags |= IEEE80211_TX_RC_USE_CTS_PROTECT;
712 	}
713 }
714 
715 
716 static void rate_control_fill_sta_table(struct ieee80211_sta *sta,
717 					struct ieee80211_tx_info *info,
718 					struct ieee80211_tx_rate *rates,
719 					int max_rates)
720 {
721 	struct ieee80211_sta_rates *ratetbl = NULL;
722 	int i;
723 
724 	if (sta && !info->control.skip_table)
725 		ratetbl = rcu_dereference(sta->rates);
726 
727 	/* Fill remaining rate slots with data from the sta rate table. */
728 	max_rates = min_t(int, max_rates, IEEE80211_TX_RATE_TABLE_SIZE);
729 	for (i = 0; i < max_rates; i++) {
730 		if (i < ARRAY_SIZE(info->control.rates) &&
731 		    info->control.rates[i].idx >= 0 &&
732 		    info->control.rates[i].count) {
733 			if (rates != info->control.rates)
734 				rates[i] = info->control.rates[i];
735 		} else if (ratetbl) {
736 			rates[i].idx = ratetbl->rate[i].idx;
737 			rates[i].flags = ratetbl->rate[i].flags;
738 			if (info->control.use_rts)
739 				rates[i].count = ratetbl->rate[i].count_rts;
740 			else if (info->control.use_cts_prot)
741 				rates[i].count = ratetbl->rate[i].count_cts;
742 			else
743 				rates[i].count = ratetbl->rate[i].count;
744 		} else {
745 			rates[i].idx = -1;
746 			rates[i].count = 0;
747 		}
748 
749 		if (rates[i].idx < 0 || !rates[i].count)
750 			break;
751 	}
752 }
753 
754 static bool rate_control_cap_mask(struct ieee80211_sub_if_data *sdata,
755 				  struct ieee80211_supported_band *sband,
756 				  struct ieee80211_sta *sta, u32 *mask,
757 				  u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN],
758 				  u16 vht_mask[NL80211_VHT_NSS_MAX])
759 {
760 	u32 i, flags;
761 
762 	*mask = sdata->rc_rateidx_mask[sband->band];
763 	flags = ieee80211_chandef_rate_flags(&sdata->vif.bss_conf.chandef);
764 	for (i = 0; i < sband->n_bitrates; i++) {
765 		if ((flags & sband->bitrates[i].flags) != flags)
766 			*mask &= ~BIT(i);
767 	}
768 
769 	if (*mask == (1 << sband->n_bitrates) - 1 &&
770 	    !sdata->rc_has_mcs_mask[sband->band] &&
771 	    !sdata->rc_has_vht_mcs_mask[sband->band])
772 		return false;
773 
774 	if (sdata->rc_has_mcs_mask[sband->band])
775 		memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[sband->band],
776 		       IEEE80211_HT_MCS_MASK_LEN);
777 	else
778 		memset(mcs_mask, 0xff, IEEE80211_HT_MCS_MASK_LEN);
779 
780 	if (sdata->rc_has_vht_mcs_mask[sband->band])
781 		memcpy(vht_mask, sdata->rc_rateidx_vht_mcs_mask[sband->band],
782 		       sizeof(u16) * NL80211_VHT_NSS_MAX);
783 	else
784 		memset(vht_mask, 0xff, sizeof(u16) * NL80211_VHT_NSS_MAX);
785 
786 	if (sta) {
787 		__le16 sta_vht_cap;
788 		u16 sta_vht_mask[NL80211_VHT_NSS_MAX];
789 
790 		/* Filter out rates that the STA does not support */
791 		*mask &= sta->deflink.supp_rates[sband->band];
792 		for (i = 0; i < IEEE80211_HT_MCS_MASK_LEN; i++)
793 			mcs_mask[i] &= sta->deflink.ht_cap.mcs.rx_mask[i];
794 
795 		sta_vht_cap = sta->deflink.vht_cap.vht_mcs.rx_mcs_map;
796 		ieee80211_get_vht_mask_from_cap(sta_vht_cap, sta_vht_mask);
797 		for (i = 0; i < NL80211_VHT_NSS_MAX; i++)
798 			vht_mask[i] &= sta_vht_mask[i];
799 	}
800 
801 	return true;
802 }
803 
804 static void
805 rate_control_apply_mask_ratetbl(struct sta_info *sta,
806 				struct ieee80211_supported_band *sband,
807 				struct ieee80211_sta_rates *rates)
808 {
809 	int i;
810 	u32 mask;
811 	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
812 	u16 vht_mask[NL80211_VHT_NSS_MAX];
813 	enum nl80211_chan_width chan_width;
814 
815 	if (!rate_control_cap_mask(sta->sdata, sband, &sta->sta, &mask,
816 				   mcs_mask, vht_mask))
817 		return;
818 
819 	chan_width = sta->sdata->vif.bss_conf.chandef.width;
820 	for (i = 0; i < IEEE80211_TX_RATE_TABLE_SIZE; i++) {
821 		if (rates->rate[i].idx < 0)
822 			break;
823 
824 		rate_idx_match_mask(&rates->rate[i].idx, &rates->rate[i].flags,
825 				    sband, chan_width, mask, mcs_mask,
826 				    vht_mask);
827 	}
828 }
829 
830 static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
831 				    struct ieee80211_sta *sta,
832 				    struct ieee80211_supported_band *sband,
833 				    struct ieee80211_tx_rate *rates,
834 				    int max_rates)
835 {
836 	enum nl80211_chan_width chan_width;
837 	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
838 	u32 mask;
839 	u16 rate_flags, vht_mask[NL80211_VHT_NSS_MAX];
840 	int i;
841 
842 	/*
843 	 * Try to enforce the rateidx mask the user wanted. skip this if the
844 	 * default mask (allow all rates) is used to save some processing for
845 	 * the common case.
846 	 */
847 	if (!rate_control_cap_mask(sdata, sband, sta, &mask, mcs_mask,
848 				   vht_mask))
849 		return;
850 
851 	/*
852 	 * Make sure the rate index selected for each TX rate is
853 	 * included in the configured mask and change the rate indexes
854 	 * if needed.
855 	 */
856 	chan_width = sdata->vif.bss_conf.chandef.width;
857 	for (i = 0; i < max_rates; i++) {
858 		/* Skip invalid rates */
859 		if (rates[i].idx < 0)
860 			break;
861 
862 		rate_flags = rates[i].flags;
863 		rate_idx_match_mask(&rates[i].idx, &rate_flags, sband,
864 				    chan_width, mask, mcs_mask, vht_mask);
865 		rates[i].flags = rate_flags;
866 	}
867 }
868 
869 void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
870 			    struct ieee80211_sta *sta,
871 			    struct sk_buff *skb,
872 			    struct ieee80211_tx_rate *dest,
873 			    int max_rates)
874 {
875 	struct ieee80211_sub_if_data *sdata;
876 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
877 	struct ieee80211_supported_band *sband;
878 
879 	rate_control_fill_sta_table(sta, info, dest, max_rates);
880 
881 	if (!vif)
882 		return;
883 
884 	sdata = vif_to_sdata(vif);
885 	sband = sdata->local->hw.wiphy->bands[info->band];
886 
887 	if (ieee80211_is_tx_data(skb))
888 		rate_control_apply_mask(sdata, sta, sband, dest, max_rates);
889 
890 	if (dest[0].idx < 0)
891 		__rate_control_send_low(&sdata->local->hw, sband, sta, info,
892 					sdata->rc_rateidx_mask[info->band]);
893 
894 	if (sta)
895 		rate_fixup_ratelist(vif, sband, info, dest, max_rates);
896 }
897 EXPORT_SYMBOL(ieee80211_get_tx_rates);
898 
899 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
900 			   struct sta_info *sta,
901 			   struct ieee80211_tx_rate_control *txrc)
902 {
903 	struct rate_control_ref *ref = sdata->local->rate_ctrl;
904 	void *priv_sta = NULL;
905 	struct ieee80211_sta *ista = NULL;
906 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
907 	int i;
908 
909 	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
910 		info->control.rates[i].idx = -1;
911 		info->control.rates[i].flags = 0;
912 		info->control.rates[i].count = 0;
913 	}
914 
915 	if (rate_control_send_low(sta ? &sta->sta : NULL, txrc))
916 		return;
917 
918 	if (ieee80211_hw_check(&sdata->local->hw, HAS_RATE_CONTROL))
919 		return;
920 
921 	if (sta && test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) {
922 		ista = &sta->sta;
923 		priv_sta = sta->rate_ctrl_priv;
924 	}
925 
926 	if (ista) {
927 		spin_lock_bh(&sta->rate_ctrl_lock);
928 		ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
929 		spin_unlock_bh(&sta->rate_ctrl_lock);
930 	} else {
931 		rate_control_send_low(NULL, txrc);
932 	}
933 
934 	if (ieee80211_hw_check(&sdata->local->hw, SUPPORTS_RC_TABLE))
935 		return;
936 
937 	ieee80211_get_tx_rates(&sdata->vif, ista, txrc->skb,
938 			       info->control.rates,
939 			       ARRAY_SIZE(info->control.rates));
940 }
941 
942 int rate_control_set_rates(struct ieee80211_hw *hw,
943 			   struct ieee80211_sta *pubsta,
944 			   struct ieee80211_sta_rates *rates)
945 {
946 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
947 	struct ieee80211_sta_rates *old;
948 	struct ieee80211_supported_band *sband;
949 
950 	sband = ieee80211_get_sband(sta->sdata);
951 	if (!sband)
952 		return -EINVAL;
953 	rate_control_apply_mask_ratetbl(sta, sband, rates);
954 	/*
955 	 * mac80211 guarantees that this function will not be called
956 	 * concurrently, so the following RCU access is safe, even without
957 	 * extra locking. This can not be checked easily, so we just set
958 	 * the condition to true.
959 	 */
960 	old = rcu_dereference_protected(pubsta->rates, true);
961 	rcu_assign_pointer(pubsta->rates, rates);
962 	if (old)
963 		kfree_rcu(old, rcu_head);
964 
965 	if (sta->uploaded)
966 		drv_sta_rate_tbl_update(hw_to_local(hw), sta->sdata, pubsta);
967 
968 	ieee80211_sta_set_expected_throughput(pubsta, sta_get_expected_throughput(sta));
969 
970 	return 0;
971 }
972 EXPORT_SYMBOL(rate_control_set_rates);
973 
974 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
975 				 const char *name)
976 {
977 	struct rate_control_ref *ref;
978 
979 	ASSERT_RTNL();
980 
981 	if (local->open_count)
982 		return -EBUSY;
983 
984 	if (ieee80211_hw_check(&local->hw, HAS_RATE_CONTROL)) {
985 		if (WARN_ON(!local->ops->set_rts_threshold))
986 			return -EINVAL;
987 		return 0;
988 	}
989 
990 	ref = rate_control_alloc(name, local);
991 	if (!ref) {
992 		wiphy_warn(local->hw.wiphy,
993 			   "Failed to select rate control algorithm\n");
994 		return -ENOENT;
995 	}
996 
997 	WARN_ON(local->rate_ctrl);
998 	local->rate_ctrl = ref;
999 
1000 	wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n",
1001 		    ref->ops->name);
1002 
1003 	return 0;
1004 }
1005 
1006 void rate_control_deinitialize(struct ieee80211_local *local)
1007 {
1008 	struct rate_control_ref *ref;
1009 
1010 	ref = local->rate_ctrl;
1011 
1012 	if (!ref)
1013 		return;
1014 
1015 	local->rate_ctrl = NULL;
1016 	rate_control_free(local, ref);
1017 }
1018