root/net/mac80211/rate.c

DEFINITIONS

1. rate_control_rate_init
2. rate_control_tx_status
3. rate_control_rate_update
4. ieee80211_rate_control_register
5. ieee80211_rate_control_unregister
6. ieee80211_try_rate_control_ops_get
7. ieee80211_rate_control_ops_get
8. rcname_read
9. rate_control_alloc
10. rate_control_free
11. ieee80211_check_rate_mask
12. rc_no_data_or_no_ack_use_min
13. rc_send_low_basicrate
14. __rate_control_send_low
15. rate_control_send_low
16. rate_idx_match_legacy_mask
17. rate_idx_match_mcs_mask
18. rate_idx_match_vht_mcs_mask
19. rate_idx_match_mask
20. rate_fixup_ratelist
21. rate_control_fill_sta_table
22. rate_control_cap_mask
23. rate_control_apply_mask_ratetbl
24. rate_control_apply_mask
25. ieee80211_get_tx_rates
26. rate_control_get_rate
27. rate_control_set_rates
28. ieee80211_init_rate_ctrl_alg
29. rate_control_deinitialize

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