xref: /openbmc/linux/net/mac80211/rate.c (revision 83d3c4f2)
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 	/* TODO: check for minstrel_s1g ? */
55 	if (sband->band == NL80211_BAND_S1GHZ) {
56 		ieee80211_s1g_sta_rate_init(sta);
57 		rcu_read_unlock();
58 		return;
59 	}
60 
61 	spin_lock_bh(&sta->rate_ctrl_lock);
62 	ref->ops->rate_init(ref->priv, sband, &chanctx_conf->def, ista,
63 			    priv_sta);
64 	spin_unlock_bh(&sta->rate_ctrl_lock);
65 	rcu_read_unlock();
66 	set_sta_flag(sta, WLAN_STA_RATE_CONTROL);
67 }
68 
69 void rate_control_tx_status(struct ieee80211_local *local,
70 			    struct ieee80211_supported_band *sband,
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 
77 	if (!ref || !test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
78 		return;
79 
80 	spin_lock_bh(&sta->rate_ctrl_lock);
81 	if (ref->ops->tx_status_ext)
82 		ref->ops->tx_status_ext(ref->priv, sband, priv_sta, st);
83 	else if (st->skb)
84 		ref->ops->tx_status(ref->priv, sband, st->sta, priv_sta, st->skb);
85 	else
86 		WARN_ON_ONCE(1);
87 
88 	spin_unlock_bh(&sta->rate_ctrl_lock);
89 }
90 
91 void rate_control_rate_update(struct ieee80211_local *local,
92 				    struct ieee80211_supported_band *sband,
93 				    struct sta_info *sta, u32 changed)
94 {
95 	struct rate_control_ref *ref = local->rate_ctrl;
96 	struct ieee80211_sta *ista = &sta->sta;
97 	void *priv_sta = sta->rate_ctrl_priv;
98 	struct ieee80211_chanctx_conf *chanctx_conf;
99 
100 	if (ref && ref->ops->rate_update) {
101 		rcu_read_lock();
102 
103 		chanctx_conf = rcu_dereference(sta->sdata->vif.chanctx_conf);
104 		if (WARN_ON(!chanctx_conf)) {
105 			rcu_read_unlock();
106 			return;
107 		}
108 
109 		spin_lock_bh(&sta->rate_ctrl_lock);
110 		ref->ops->rate_update(ref->priv, sband, &chanctx_conf->def,
111 				      ista, priv_sta, changed);
112 		spin_unlock_bh(&sta->rate_ctrl_lock);
113 		rcu_read_unlock();
114 	}
115 	drv_sta_rc_update(local, sta->sdata, &sta->sta, changed);
116 }
117 
118 int ieee80211_rate_control_register(const struct rate_control_ops *ops)
119 {
120 	struct rate_control_alg *alg;
121 
122 	if (!ops->name)
123 		return -EINVAL;
124 
125 	mutex_lock(&rate_ctrl_mutex);
126 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
127 		if (!strcmp(alg->ops->name, ops->name)) {
128 			/* don't register an algorithm twice */
129 			WARN_ON(1);
130 			mutex_unlock(&rate_ctrl_mutex);
131 			return -EALREADY;
132 		}
133 	}
134 
135 	alg = kzalloc(sizeof(*alg), GFP_KERNEL);
136 	if (alg == NULL) {
137 		mutex_unlock(&rate_ctrl_mutex);
138 		return -ENOMEM;
139 	}
140 	alg->ops = ops;
141 
142 	list_add_tail(&alg->list, &rate_ctrl_algs);
143 	mutex_unlock(&rate_ctrl_mutex);
144 
145 	return 0;
146 }
147 EXPORT_SYMBOL(ieee80211_rate_control_register);
148 
149 void ieee80211_rate_control_unregister(const struct rate_control_ops *ops)
150 {
151 	struct rate_control_alg *alg;
152 
153 	mutex_lock(&rate_ctrl_mutex);
154 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
155 		if (alg->ops == ops) {
156 			list_del(&alg->list);
157 			kfree(alg);
158 			break;
159 		}
160 	}
161 	mutex_unlock(&rate_ctrl_mutex);
162 }
163 EXPORT_SYMBOL(ieee80211_rate_control_unregister);
164 
165 static const struct rate_control_ops *
166 ieee80211_try_rate_control_ops_get(const char *name)
167 {
168 	struct rate_control_alg *alg;
169 	const struct rate_control_ops *ops = NULL;
170 
171 	if (!name)
172 		return NULL;
173 
174 	mutex_lock(&rate_ctrl_mutex);
175 	list_for_each_entry(alg, &rate_ctrl_algs, list) {
176 		if (!strcmp(alg->ops->name, name)) {
177 			ops = alg->ops;
178 			break;
179 		}
180 	}
181 	mutex_unlock(&rate_ctrl_mutex);
182 	return ops;
183 }
184 
185 /* Get the rate control algorithm. */
186 static const struct rate_control_ops *
187 ieee80211_rate_control_ops_get(const char *name)
188 {
189 	const struct rate_control_ops *ops;
190 	const char *alg_name;
191 
192 	kernel_param_lock(THIS_MODULE);
193 	if (!name)
194 		alg_name = ieee80211_default_rc_algo;
195 	else
196 		alg_name = name;
197 
198 	ops = ieee80211_try_rate_control_ops_get(alg_name);
199 	if (!ops && name)
200 		/* try default if specific alg requested but not found */
201 		ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);
202 
203 	/* Note: check for > 0 is intentional to avoid clang warning */
204 	if (!ops && (strlen(CONFIG_MAC80211_RC_DEFAULT) > 0))
205 		/* try built-in one if specific alg requested but not found */
206 		ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
207 
208 	kernel_param_unlock(THIS_MODULE);
209 
210 	return ops;
211 }
212 
213 #ifdef CONFIG_MAC80211_DEBUGFS
214 static ssize_t rcname_read(struct file *file, char __user *userbuf,
215 			   size_t count, loff_t *ppos)
216 {
217 	struct rate_control_ref *ref = file->private_data;
218 	int len = strlen(ref->ops->name);
219 
220 	return simple_read_from_buffer(userbuf, count, ppos,
221 				       ref->ops->name, len);
222 }
223 
224 const struct file_operations rcname_ops = {
225 	.read = rcname_read,
226 	.open = simple_open,
227 	.llseek = default_llseek,
228 };
229 #endif
230 
231 static struct rate_control_ref *
232 rate_control_alloc(const char *name, struct ieee80211_local *local)
233 {
234 	struct rate_control_ref *ref;
235 
236 	ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
237 	if (!ref)
238 		return NULL;
239 	ref->ops = ieee80211_rate_control_ops_get(name);
240 	if (!ref->ops)
241 		goto free;
242 
243 	ref->priv = ref->ops->alloc(&local->hw);
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 	band = sdata->vif.bss_conf.chandef.chan->band;
277 	if (band == NL80211_BAND_S1GHZ) {
278 		/* TODO */
279 		return;
280 	}
281 
282 	if (WARN_ON_ONCE(!basic_rates))
283 		return;
284 
285 	user_mask = sdata->rc_rateidx_mask[band];
286 	sband = local->hw.wiphy->bands[band];
287 
288 	if (user_mask & basic_rates)
289 		return;
290 
291 	sdata_dbg(sdata,
292 		  "no overlap between basic rates (0x%x) and user mask (0x%x on band %d) - clearing the latter",
293 		  basic_rates, user_mask, band);
294 	sdata->rc_rateidx_mask[band] = (1 << sband->n_bitrates) - 1;
295 }
296 
297 static bool rc_no_data_or_no_ack_use_min(struct ieee80211_tx_rate_control *txrc)
298 {
299 	struct sk_buff *skb = txrc->skb;
300 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
301 
302 	return (info->flags & (IEEE80211_TX_CTL_NO_ACK |
303 			       IEEE80211_TX_CTL_USE_MINRATE)) ||
304 		!ieee80211_is_tx_data(skb);
305 }
306 
307 static void rc_send_low_basicrate(struct ieee80211_tx_rate *rate,
308 				  u32 basic_rates,
309 				  struct ieee80211_supported_band *sband)
310 {
311 	u8 i;
312 
313 	if (sband->band == NL80211_BAND_S1GHZ) {
314 		/* TODO */
315 		rate->flags |= IEEE80211_TX_RC_S1G_MCS;
316 		rate->idx = 0;
317 		return;
318 	}
319 
320 	if (basic_rates == 0)
321 		return; /* assume basic rates unknown and accept rate */
322 	if (rate->idx < 0)
323 		return;
324 	if (basic_rates & (1 << rate->idx))
325 		return; /* selected rate is a basic rate */
326 
327 	for (i = rate->idx + 1; i <= sband->n_bitrates; i++) {
328 		if (basic_rates & (1 << i)) {
329 			rate->idx = i;
330 			return;
331 		}
332 	}
333 
334 	/* could not find a basic rate; use original selection */
335 }
336 
337 static void __rate_control_send_low(struct ieee80211_hw *hw,
338 				    struct ieee80211_supported_band *sband,
339 				    struct ieee80211_sta *sta,
340 				    struct ieee80211_tx_info *info,
341 				    u32 rate_mask)
342 {
343 	int i;
344 	u32 rate_flags =
345 		ieee80211_chandef_rate_flags(&hw->conf.chandef);
346 
347 	if (sband->band == NL80211_BAND_S1GHZ) {
348 		info->control.rates[0].flags |= IEEE80211_TX_RC_S1G_MCS;
349 		info->control.rates[0].idx = 0;
350 		return;
351 	}
352 
353 	if ((sband->band == NL80211_BAND_2GHZ) &&
354 	    (info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
355 		rate_flags |= IEEE80211_RATE_ERP_G;
356 
357 	info->control.rates[0].idx = 0;
358 	for (i = 0; i < sband->n_bitrates; i++) {
359 		if (!(rate_mask & BIT(i)))
360 			continue;
361 
362 		if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
363 			continue;
364 
365 		if (!rate_supported(sta, sband->band, i))
366 			continue;
367 
368 		info->control.rates[0].idx = i;
369 		break;
370 	}
371 	WARN_ONCE(i == sband->n_bitrates,
372 		  "no supported rates for sta %pM (0x%x, band %d) in rate_mask 0x%x with flags 0x%x\n",
373 		  sta ? sta->addr : NULL,
374 		  sta ? sta->supp_rates[sband->band] : -1,
375 		  sband->band,
376 		  rate_mask, rate_flags);
377 
378 	info->control.rates[0].count =
379 		(info->flags & IEEE80211_TX_CTL_NO_ACK) ?
380 		1 : hw->max_rate_tries;
381 
382 	info->control.skip_table = 1;
383 }
384 
385 
386 static bool rate_control_send_low(struct ieee80211_sta *pubsta,
387 				  struct ieee80211_tx_rate_control *txrc)
388 {
389 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
390 	struct ieee80211_supported_band *sband = txrc->sband;
391 	struct sta_info *sta;
392 	int mcast_rate;
393 	bool use_basicrate = false;
394 
395 	if (!pubsta || rc_no_data_or_no_ack_use_min(txrc)) {
396 		__rate_control_send_low(txrc->hw, sband, pubsta, info,
397 					txrc->rate_idx_mask);
398 
399 		if (!pubsta && txrc->bss) {
400 			mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
401 			if (mcast_rate > 0) {
402 				info->control.rates[0].idx = mcast_rate - 1;
403 				return true;
404 			}
405 			use_basicrate = true;
406 		} else if (pubsta) {
407 			sta = container_of(pubsta, struct sta_info, sta);
408 			if (ieee80211_vif_is_mesh(&sta->sdata->vif))
409 				use_basicrate = true;
410 		}
411 
412 		if (use_basicrate)
413 			rc_send_low_basicrate(&info->control.rates[0],
414 					      txrc->bss_conf->basic_rates,
415 					      sband);
416 
417 		return true;
418 	}
419 	return false;
420 }
421 
422 static bool rate_idx_match_legacy_mask(s8 *rate_idx, int n_bitrates, u32 mask)
423 {
424 	int j;
425 
426 	/* See whether the selected rate or anything below it is allowed. */
427 	for (j = *rate_idx; j >= 0; j--) {
428 		if (mask & (1 << j)) {
429 			/* Okay, found a suitable rate. Use it. */
430 			*rate_idx = j;
431 			return true;
432 		}
433 	}
434 
435 	/* Try to find a higher rate that would be allowed */
436 	for (j = *rate_idx + 1; j < n_bitrates; j++) {
437 		if (mask & (1 << j)) {
438 			/* Okay, found a suitable rate. Use it. */
439 			*rate_idx = j;
440 			return true;
441 		}
442 	}
443 	return false;
444 }
445 
446 static bool rate_idx_match_mcs_mask(s8 *rate_idx, u8 *mcs_mask)
447 {
448 	int i, j;
449 	int ridx, rbit;
450 
451 	ridx = *rate_idx / 8;
452 	rbit = *rate_idx % 8;
453 
454 	/* sanity check */
455 	if (ridx < 0 || ridx >= IEEE80211_HT_MCS_MASK_LEN)
456 		return false;
457 
458 	/* See whether the selected rate or anything below it is allowed. */
459 	for (i = ridx; i >= 0; i--) {
460 		for (j = rbit; j >= 0; j--)
461 			if (mcs_mask[i] & BIT(j)) {
462 				*rate_idx = i * 8 + j;
463 				return true;
464 			}
465 		rbit = 7;
466 	}
467 
468 	/* Try to find a higher rate that would be allowed */
469 	ridx = (*rate_idx + 1) / 8;
470 	rbit = (*rate_idx + 1) % 8;
471 
472 	for (i = ridx; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
473 		for (j = rbit; j < 8; j++)
474 			if (mcs_mask[i] & BIT(j)) {
475 				*rate_idx = i * 8 + j;
476 				return true;
477 			}
478 		rbit = 0;
479 	}
480 	return false;
481 }
482 
483 static bool rate_idx_match_vht_mcs_mask(s8 *rate_idx, u16 *vht_mask)
484 {
485 	int i, j;
486 	int ridx, rbit;
487 
488 	ridx = *rate_idx >> 4;
489 	rbit = *rate_idx & 0xf;
490 
491 	if (ridx < 0 || ridx >= NL80211_VHT_NSS_MAX)
492 		return false;
493 
494 	/* See whether the selected rate or anything below it is allowed. */
495 	for (i = ridx; i >= 0; i--) {
496 		for (j = rbit; j >= 0; j--) {
497 			if (vht_mask[i] & BIT(j)) {
498 				*rate_idx = (i << 4) | j;
499 				return true;
500 			}
501 		}
502 		rbit = 15;
503 	}
504 
505 	/* Try to find a higher rate that would be allowed */
506 	ridx = (*rate_idx + 1) >> 4;
507 	rbit = (*rate_idx + 1) & 0xf;
508 
509 	for (i = ridx; i < NL80211_VHT_NSS_MAX; i++) {
510 		for (j = rbit; j < 16; j++) {
511 			if (vht_mask[i] & BIT(j)) {
512 				*rate_idx = (i << 4) | j;
513 				return true;
514 			}
515 		}
516 		rbit = 0;
517 	}
518 	return false;
519 }
520 
521 static void rate_idx_match_mask(s8 *rate_idx, u16 *rate_flags,
522 				struct ieee80211_supported_band *sband,
523 				enum nl80211_chan_width chan_width,
524 				u32 mask,
525 				u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN],
526 				u16 vht_mask[NL80211_VHT_NSS_MAX])
527 {
528 	if (*rate_flags & IEEE80211_TX_RC_VHT_MCS) {
529 		/* handle VHT rates */
530 		if (rate_idx_match_vht_mcs_mask(rate_idx, vht_mask))
531 			return;
532 
533 		*rate_idx = 0;
534 		/* keep protection flags */
535 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
536 				IEEE80211_TX_RC_USE_CTS_PROTECT |
537 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
538 
539 		*rate_flags |= IEEE80211_TX_RC_MCS;
540 		if (chan_width == NL80211_CHAN_WIDTH_40)
541 			*rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
542 
543 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
544 			return;
545 
546 		/* also try the legacy rates. */
547 		*rate_flags &= ~(IEEE80211_TX_RC_MCS |
548 				 IEEE80211_TX_RC_40_MHZ_WIDTH);
549 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
550 					       mask))
551 			return;
552 	} else if (*rate_flags & IEEE80211_TX_RC_MCS) {
553 		/* handle HT rates */
554 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
555 			return;
556 
557 		/* also try the legacy rates. */
558 		*rate_idx = 0;
559 		/* keep protection flags */
560 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
561 				IEEE80211_TX_RC_USE_CTS_PROTECT |
562 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
563 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
564 					       mask))
565 			return;
566 	} else {
567 		/* handle legacy rates */
568 		if (rate_idx_match_legacy_mask(rate_idx, sband->n_bitrates,
569 					       mask))
570 			return;
571 
572 		/* if HT BSS, and we handle a data frame, also try HT rates */
573 		switch (chan_width) {
574 		case NL80211_CHAN_WIDTH_20_NOHT:
575 		case NL80211_CHAN_WIDTH_5:
576 		case NL80211_CHAN_WIDTH_10:
577 			return;
578 		default:
579 			break;
580 		}
581 
582 		*rate_idx = 0;
583 		/* keep protection flags */
584 		*rate_flags &= (IEEE80211_TX_RC_USE_RTS_CTS |
585 				IEEE80211_TX_RC_USE_CTS_PROTECT |
586 				IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
587 
588 		*rate_flags |= IEEE80211_TX_RC_MCS;
589 
590 		if (chan_width == NL80211_CHAN_WIDTH_40)
591 			*rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
592 
593 		if (rate_idx_match_mcs_mask(rate_idx, mcs_mask))
594 			return;
595 	}
596 
597 	/*
598 	 * Uh.. No suitable rate exists. This should not really happen with
599 	 * sane TX rate mask configurations. However, should someone manage to
600 	 * configure supported rates and TX rate mask in incompatible way,
601 	 * allow the frame to be transmitted with whatever the rate control
602 	 * selected.
603 	 */
604 }
605 
606 static void rate_fixup_ratelist(struct ieee80211_vif *vif,
607 				struct ieee80211_supported_band *sband,
608 				struct ieee80211_tx_info *info,
609 				struct ieee80211_tx_rate *rates,
610 				int max_rates)
611 {
612 	struct ieee80211_rate *rate;
613 	bool inval = false;
614 	int i;
615 
616 	/*
617 	 * Set up the RTS/CTS rate as the fastest basic rate
618 	 * that is not faster than the data rate unless there
619 	 * is no basic rate slower than the data rate, in which
620 	 * case we pick the slowest basic rate
621 	 *
622 	 * XXX: Should this check all retry rates?
623 	 */
624 	if (!(rates[0].flags &
625 	      (IEEE80211_TX_RC_MCS | IEEE80211_TX_RC_VHT_MCS))) {
626 		u32 basic_rates = vif->bss_conf.basic_rates;
627 		s8 baserate = basic_rates ? ffs(basic_rates) - 1 : 0;
628 
629 		rate = &sband->bitrates[rates[0].idx];
630 
631 		for (i = 0; i < sband->n_bitrates; i++) {
632 			/* must be a basic rate */
633 			if (!(basic_rates & BIT(i)))
634 				continue;
635 			/* must not be faster than the data rate */
636 			if (sband->bitrates[i].bitrate > rate->bitrate)
637 				continue;
638 			/* maximum */
639 			if (sband->bitrates[baserate].bitrate <
640 			     sband->bitrates[i].bitrate)
641 				baserate = i;
642 		}
643 
644 		info->control.rts_cts_rate_idx = baserate;
645 	}
646 
647 	for (i = 0; i < max_rates; i++) {
648 		/*
649 		 * make sure there's no valid rate following
650 		 * an invalid one, just in case drivers don't
651 		 * take the API seriously to stop at -1.
652 		 */
653 		if (inval) {
654 			rates[i].idx = -1;
655 			continue;
656 		}
657 		if (rates[i].idx < 0) {
658 			inval = true;
659 			continue;
660 		}
661 
662 		/*
663 		 * For now assume MCS is already set up correctly, this
664 		 * needs to be fixed.
665 		 */
666 		if (rates[i].flags & IEEE80211_TX_RC_MCS) {
667 			WARN_ON(rates[i].idx > 76);
668 
669 			if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
670 			    info->control.use_cts_prot)
671 				rates[i].flags |=
672 					IEEE80211_TX_RC_USE_CTS_PROTECT;
673 			continue;
674 		}
675 
676 		if (rates[i].flags & IEEE80211_TX_RC_VHT_MCS) {
677 			WARN_ON(ieee80211_rate_get_vht_mcs(&rates[i]) > 9);
678 			continue;
679 		}
680 
681 		/* set up RTS protection if desired */
682 		if (info->control.use_rts) {
683 			rates[i].flags |= IEEE80211_TX_RC_USE_RTS_CTS;
684 			info->control.use_cts_prot = false;
685 		}
686 
687 		/* RC is busted */
688 		if (WARN_ON_ONCE(rates[i].idx >= sband->n_bitrates)) {
689 			rates[i].idx = -1;
690 			continue;
691 		}
692 
693 		rate = &sband->bitrates[rates[i].idx];
694 
695 		/* set up short preamble */
696 		if (info->control.short_preamble &&
697 		    rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
698 			rates[i].flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
699 
700 		/* set up G protection */
701 		if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
702 		    info->control.use_cts_prot &&
703 		    rate->flags & IEEE80211_RATE_ERP_G)
704 			rates[i].flags |= IEEE80211_TX_RC_USE_CTS_PROTECT;
705 	}
706 }
707 
708 
709 static void rate_control_fill_sta_table(struct ieee80211_sta *sta,
710 					struct ieee80211_tx_info *info,
711 					struct ieee80211_tx_rate *rates,
712 					int max_rates)
713 {
714 	struct ieee80211_sta_rates *ratetbl = NULL;
715 	int i;
716 
717 	if (sta && !info->control.skip_table)
718 		ratetbl = rcu_dereference(sta->rates);
719 
720 	/* Fill remaining rate slots with data from the sta rate table. */
721 	max_rates = min_t(int, max_rates, IEEE80211_TX_RATE_TABLE_SIZE);
722 	for (i = 0; i < max_rates; i++) {
723 		if (i < ARRAY_SIZE(info->control.rates) &&
724 		    info->control.rates[i].idx >= 0 &&
725 		    info->control.rates[i].count) {
726 			if (rates != info->control.rates)
727 				rates[i] = info->control.rates[i];
728 		} else if (ratetbl) {
729 			rates[i].idx = ratetbl->rate[i].idx;
730 			rates[i].flags = ratetbl->rate[i].flags;
731 			if (info->control.use_rts)
732 				rates[i].count = ratetbl->rate[i].count_rts;
733 			else if (info->control.use_cts_prot)
734 				rates[i].count = ratetbl->rate[i].count_cts;
735 			else
736 				rates[i].count = ratetbl->rate[i].count;
737 		} else {
738 			rates[i].idx = -1;
739 			rates[i].count = 0;
740 		}
741 
742 		if (rates[i].idx < 0 || !rates[i].count)
743 			break;
744 	}
745 }
746 
747 static bool rate_control_cap_mask(struct ieee80211_sub_if_data *sdata,
748 				  struct ieee80211_supported_band *sband,
749 				  struct ieee80211_sta *sta, u32 *mask,
750 				  u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN],
751 				  u16 vht_mask[NL80211_VHT_NSS_MAX])
752 {
753 	u32 i, flags;
754 
755 	*mask = sdata->rc_rateidx_mask[sband->band];
756 	flags = ieee80211_chandef_rate_flags(&sdata->vif.bss_conf.chandef);
757 	for (i = 0; i < sband->n_bitrates; i++) {
758 		if ((flags & sband->bitrates[i].flags) != flags)
759 			*mask &= ~BIT(i);
760 	}
761 
762 	if (*mask == (1 << sband->n_bitrates) - 1 &&
763 	    !sdata->rc_has_mcs_mask[sband->band] &&
764 	    !sdata->rc_has_vht_mcs_mask[sband->band])
765 		return false;
766 
767 	if (sdata->rc_has_mcs_mask[sband->band])
768 		memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[sband->band],
769 		       IEEE80211_HT_MCS_MASK_LEN);
770 	else
771 		memset(mcs_mask, 0xff, IEEE80211_HT_MCS_MASK_LEN);
772 
773 	if (sdata->rc_has_vht_mcs_mask[sband->band])
774 		memcpy(vht_mask, sdata->rc_rateidx_vht_mcs_mask[sband->band],
775 		       sizeof(u16) * NL80211_VHT_NSS_MAX);
776 	else
777 		memset(vht_mask, 0xff, sizeof(u16) * NL80211_VHT_NSS_MAX);
778 
779 	if (sta) {
780 		__le16 sta_vht_cap;
781 		u16 sta_vht_mask[NL80211_VHT_NSS_MAX];
782 
783 		/* Filter out rates that the STA does not support */
784 		*mask &= sta->supp_rates[sband->band];
785 		for (i = 0; i < IEEE80211_HT_MCS_MASK_LEN; i++)
786 			mcs_mask[i] &= sta->ht_cap.mcs.rx_mask[i];
787 
788 		sta_vht_cap = sta->vht_cap.vht_mcs.rx_mcs_map;
789 		ieee80211_get_vht_mask_from_cap(sta_vht_cap, sta_vht_mask);
790 		for (i = 0; i < NL80211_VHT_NSS_MAX; i++)
791 			vht_mask[i] &= sta_vht_mask[i];
792 	}
793 
794 	return true;
795 }
796 
797 static void
798 rate_control_apply_mask_ratetbl(struct sta_info *sta,
799 				struct ieee80211_supported_band *sband,
800 				struct ieee80211_sta_rates *rates)
801 {
802 	int i;
803 	u32 mask;
804 	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
805 	u16 vht_mask[NL80211_VHT_NSS_MAX];
806 	enum nl80211_chan_width chan_width;
807 
808 	if (!rate_control_cap_mask(sta->sdata, sband, &sta->sta, &mask,
809 				   mcs_mask, vht_mask))
810 		return;
811 
812 	chan_width = sta->sdata->vif.bss_conf.chandef.width;
813 	for (i = 0; i < IEEE80211_TX_RATE_TABLE_SIZE; i++) {
814 		if (rates->rate[i].idx < 0)
815 			break;
816 
817 		rate_idx_match_mask(&rates->rate[i].idx, &rates->rate[i].flags,
818 				    sband, chan_width, mask, mcs_mask,
819 				    vht_mask);
820 	}
821 }
822 
823 static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
824 				    struct ieee80211_sta *sta,
825 				    struct ieee80211_supported_band *sband,
826 				    struct ieee80211_tx_rate *rates,
827 				    int max_rates)
828 {
829 	enum nl80211_chan_width chan_width;
830 	u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
831 	u32 mask;
832 	u16 rate_flags, vht_mask[NL80211_VHT_NSS_MAX];
833 	int i;
834 
835 	/*
836 	 * Try to enforce the rateidx mask the user wanted. skip this if the
837 	 * default mask (allow all rates) is used to save some processing for
838 	 * the common case.
839 	 */
840 	if (!rate_control_cap_mask(sdata, sband, sta, &mask, mcs_mask,
841 				   vht_mask))
842 		return;
843 
844 	/*
845 	 * Make sure the rate index selected for each TX rate is
846 	 * included in the configured mask and change the rate indexes
847 	 * if needed.
848 	 */
849 	chan_width = sdata->vif.bss_conf.chandef.width;
850 	for (i = 0; i < max_rates; i++) {
851 		/* Skip invalid rates */
852 		if (rates[i].idx < 0)
853 			break;
854 
855 		rate_flags = rates[i].flags;
856 		rate_idx_match_mask(&rates[i].idx, &rate_flags, sband,
857 				    chan_width, mask, mcs_mask, vht_mask);
858 		rates[i].flags = rate_flags;
859 	}
860 }
861 
862 void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
863 			    struct ieee80211_sta *sta,
864 			    struct sk_buff *skb,
865 			    struct ieee80211_tx_rate *dest,
866 			    int max_rates)
867 {
868 	struct ieee80211_sub_if_data *sdata;
869 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
870 	struct ieee80211_supported_band *sband;
871 
872 	rate_control_fill_sta_table(sta, info, dest, max_rates);
873 
874 	if (!vif)
875 		return;
876 
877 	sdata = vif_to_sdata(vif);
878 	sband = sdata->local->hw.wiphy->bands[info->band];
879 
880 	if (ieee80211_is_tx_data(skb))
881 		rate_control_apply_mask(sdata, sta, sband, dest, max_rates);
882 
883 	if (dest[0].idx < 0)
884 		__rate_control_send_low(&sdata->local->hw, sband, sta, info,
885 					sdata->rc_rateidx_mask[info->band]);
886 
887 	if (sta)
888 		rate_fixup_ratelist(vif, sband, info, dest, max_rates);
889 }
890 EXPORT_SYMBOL(ieee80211_get_tx_rates);
891 
892 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
893 			   struct sta_info *sta,
894 			   struct ieee80211_tx_rate_control *txrc)
895 {
896 	struct rate_control_ref *ref = sdata->local->rate_ctrl;
897 	void *priv_sta = NULL;
898 	struct ieee80211_sta *ista = NULL;
899 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
900 	int i;
901 
902 	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
903 		info->control.rates[i].idx = -1;
904 		info->control.rates[i].flags = 0;
905 		info->control.rates[i].count = 0;
906 	}
907 
908 	if (rate_control_send_low(sta ? &sta->sta : NULL, txrc))
909 		return;
910 
911 	if (ieee80211_hw_check(&sdata->local->hw, HAS_RATE_CONTROL))
912 		return;
913 
914 	if (sta && test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) {
915 		ista = &sta->sta;
916 		priv_sta = sta->rate_ctrl_priv;
917 	}
918 
919 	if (ista) {
920 		spin_lock_bh(&sta->rate_ctrl_lock);
921 		ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
922 		spin_unlock_bh(&sta->rate_ctrl_lock);
923 	} else {
924 		rate_control_send_low(NULL, txrc);
925 	}
926 
927 	if (ieee80211_hw_check(&sdata->local->hw, SUPPORTS_RC_TABLE))
928 		return;
929 
930 	ieee80211_get_tx_rates(&sdata->vif, ista, txrc->skb,
931 			       info->control.rates,
932 			       ARRAY_SIZE(info->control.rates));
933 }
934 
935 int rate_control_set_rates(struct ieee80211_hw *hw,
936 			   struct ieee80211_sta *pubsta,
937 			   struct ieee80211_sta_rates *rates)
938 {
939 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
940 	struct ieee80211_sta_rates *old;
941 	struct ieee80211_supported_band *sband;
942 
943 	sband = ieee80211_get_sband(sta->sdata);
944 	if (!sband)
945 		return -EINVAL;
946 	rate_control_apply_mask_ratetbl(sta, sband, rates);
947 	/*
948 	 * mac80211 guarantees that this function will not be called
949 	 * concurrently, so the following RCU access is safe, even without
950 	 * extra locking. This can not be checked easily, so we just set
951 	 * the condition to true.
952 	 */
953 	old = rcu_dereference_protected(pubsta->rates, true);
954 	rcu_assign_pointer(pubsta->rates, rates);
955 	if (old)
956 		kfree_rcu(old, rcu_head);
957 
958 	if (sta->uploaded)
959 		drv_sta_rate_tbl_update(hw_to_local(hw), sta->sdata, pubsta);
960 
961 	ieee80211_sta_set_expected_throughput(pubsta, sta_get_expected_throughput(sta));
962 
963 	return 0;
964 }
965 EXPORT_SYMBOL(rate_control_set_rates);
966 
967 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
968 				 const char *name)
969 {
970 	struct rate_control_ref *ref;
971 
972 	ASSERT_RTNL();
973 
974 	if (local->open_count)
975 		return -EBUSY;
976 
977 	if (ieee80211_hw_check(&local->hw, HAS_RATE_CONTROL)) {
978 		if (WARN_ON(!local->ops->set_rts_threshold))
979 			return -EINVAL;
980 		return 0;
981 	}
982 
983 	ref = rate_control_alloc(name, local);
984 	if (!ref) {
985 		wiphy_warn(local->hw.wiphy,
986 			   "Failed to select rate control algorithm\n");
987 		return -ENOENT;
988 	}
989 
990 	WARN_ON(local->rate_ctrl);
991 	local->rate_ctrl = ref;
992 
993 	wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n",
994 		    ref->ops->name);
995 
996 	return 0;
997 }
998 
999 void rate_control_deinitialize(struct ieee80211_local *local)
1000 {
1001 	struct rate_control_ref *ref;
1002 
1003 	ref = local->rate_ctrl;
1004 
1005 	if (!ref)
1006 		return;
1007 
1008 	local->rate_ctrl = NULL;
1009 	rate_control_free(local, ref);
1010 }
1011