net/mac80211/rate.c

   1 /*
   2  * Copyright 2002-2005, Instant802 Networks, Inc.
   3  * Copyright 2005-2006, Devicescape Software, Inc.
   4  * Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/rtnetlink.h>
  13 #include <linux/slab.h>
  14 #include <linux/module.h>
  15 #include "rate.h"
  16 #include "ieee80211_i.h"
  17 #include "debugfs.h"
  18
  19 struct rate_control_alg {
  20         struct list_head list;
  21         struct rate_control_ops *ops;
  22 };
  23
  24 static LIST_HEAD(rate_ctrl_algs);
  25 static DEFINE_MUTEX(rate_ctrl_mutex);
  26
  27 static char *ieee80211_default_rc_algo = CONFIG_MAC80211_RC_DEFAULT;
  28 module_param(ieee80211_default_rc_algo, charp, 0644);
  29 MODULE_PARM_DESC(ieee80211_default_rc_algo,
  30                  "Default rate control algorithm for mac80211 to use");
  31
  32 int ieee80211_rate_control_register(struct rate_control_ops *ops)
  33 {
  34         struct rate_control_alg *alg;
  35
  36         if (!ops->name)
  37                 return -EINVAL;
  38
  39         mutex_lock(&rate_ctrl_mutex);
  40         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  41                 if (!strcmp(alg->ops->name, ops->name)) {
  42                         /* don't register an algorithm twice */
  43                         WARN_ON(1);
  44                         mutex_unlock(&rate_ctrl_mutex);
  45                         return -EALREADY;
  46                 }
  47         }
  48
  49         alg = kzalloc(sizeof(*alg), GFP_KERNEL);
  50         if (alg == NULL) {
  51                 mutex_unlock(&rate_ctrl_mutex);
  52                 return -ENOMEM;
  53         }
  54         alg->ops = ops;
  55
  56         list_add_tail(&alg->list, &rate_ctrl_algs);
  57         mutex_unlock(&rate_ctrl_mutex);
  58
  59         return 0;
  60 }
  61 EXPORT_SYMBOL(ieee80211_rate_control_register);
  62
  63 void ieee80211_rate_control_unregister(struct rate_control_ops *ops)
  64 {
  65         struct rate_control_alg *alg;
  66
  67         mutex_lock(&rate_ctrl_mutex);
  68         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  69                 if (alg->ops == ops) {
  70                         list_del(&alg->list);
  71                         kfree(alg);
  72                         break;
  73                 }
  74         }
  75         mutex_unlock(&rate_ctrl_mutex);
  76 }
  77 EXPORT_SYMBOL(ieee80211_rate_control_unregister);
  78
  79 static struct rate_control_ops *
  80 ieee80211_try_rate_control_ops_get(const char *name)
  81 {
  82         struct rate_control_alg *alg;
  83         struct rate_control_ops *ops = NULL;
  84
  85         if (!name)
  86                 return NULL;
  87
  88         mutex_lock(&rate_ctrl_mutex);
  89         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  90                 if (!strcmp(alg->ops->name, name))
  91                         if (try_module_get(alg->ops->module)) {
  92                                 ops = alg->ops;
  93                                 break;
  94                         }
  95         }
  96         mutex_unlock(&rate_ctrl_mutex);
  97         return ops;
  98 }
  99
 100 /* Get the rate control algorithm. */
 101 static struct rate_control_ops *
 102 ieee80211_rate_control_ops_get(const char *name)
 103 {
 104         struct rate_control_ops *ops;
 105         const char *alg_name;
 106
 107         kparam_block_sysfs_write(ieee80211_default_rc_algo);
 108         if (!name)
 109                 alg_name = ieee80211_default_rc_algo;
 110         else
 111                 alg_name = name;
 112
 113         ops = ieee80211_try_rate_control_ops_get(alg_name);
 114         if (!ops) {
 115                 request_module("rc80211_%s", alg_name);
 116                 ops = ieee80211_try_rate_control_ops_get(alg_name);
 117         }
 118         if (!ops && name)
 119                 /* try default if specific alg requested but not found */
 120                 ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);
 121
 122         /* try built-in one if specific alg requested but not found */
 123         if (!ops && strlen(CONFIG_MAC80211_RC_DEFAULT))
 124                 ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
 125         kparam_unblock_sysfs_write(ieee80211_default_rc_algo);
 126
 127         return ops;
 128 }
 129
 130 static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops)
 131 {
 132         module_put(ops->module);
 133 }
 134
 135 #ifdef CONFIG_MAC80211_DEBUGFS
 136 static ssize_t rcname_read(struct file *file, char __user *userbuf,
 137                            size_t count, loff_t *ppos)
 138 {
 139         struct rate_control_ref *ref = file->private_data;
 140         int len = strlen(ref->ops->name);
 141
 142         return simple_read_from_buffer(userbuf, count, ppos,
 143                                        ref->ops->name, len);
 144 }
 145
 146 static const struct file_operations rcname_ops = {
 147         .read = rcname_read,
 148         .open = simple_open,
 149         .llseek = default_llseek,
 150 };
 151 #endif
 152
 153 static struct rate_control_ref *rate_control_alloc(const char *name,
 154                                             struct ieee80211_local *local)
 155 {
 156         struct dentry *debugfsdir = NULL;
 157         struct rate_control_ref *ref;
 158
 159         ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
 160         if (!ref)
 161                 goto fail_ref;
 162         ref->local = local;
 163         ref->ops = ieee80211_rate_control_ops_get(name);
 164         if (!ref->ops)
 165                 goto fail_ops;
 166
 167 #ifdef CONFIG_MAC80211_DEBUGFS
 168         debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir);
 169         local->debugfs.rcdir = debugfsdir;
 170         debugfs_create_file("name", 0400, debugfsdir, ref, &rcname_ops);
 171 #endif
 172
 173         ref->priv = ref->ops->alloc(&local->hw, debugfsdir);
 174         if (!ref->priv)
 175                 goto fail_priv;
 176         return ref;
 177
 178 fail_priv:
 179         ieee80211_rate_control_ops_put(ref->ops);
 180 fail_ops:
 181         kfree(ref);
 182 fail_ref:
 183         return NULL;
 184 }
 185
 186 static void rate_control_free(struct rate_control_ref *ctrl_ref)
 187 {
 188         ctrl_ref->ops->free(ctrl_ref->priv);
 189
 190 #ifdef CONFIG_MAC80211_DEBUGFS
 191         debugfs_remove_recursive(ctrl_ref->local->debugfs.rcdir);
 192         ctrl_ref->local->debugfs.rcdir = NULL;
 193 #endif
 194
 195         ieee80211_rate_control_ops_put(ctrl_ref->ops);
 196         kfree(ctrl_ref);
 197 }
 198
 199 static bool rc_no_data_or_no_ack_use_min(struct ieee80211_tx_rate_control *txrc)
 200 {
 201         struct sk_buff *skb = txrc->skb;
 202         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 203         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 204         __le16 fc;
 205
 206         fc = hdr->frame_control;
 207
 208         return (info->flags & (IEEE80211_TX_CTL_NO_ACK |
 209                                IEEE80211_TX_CTL_USE_MINRATE)) ||
 210                 !ieee80211_is_data(fc);
 211 }
 212
 213 static void rc_send_low_basicrate(s8 *idx, u32 basic_rates,
 214                                   struct ieee80211_supported_band *sband)
 215 {
 216         u8 i;
 217
 218         if (basic_rates == 0)
 219                 return; /* assume basic rates unknown and accept rate */
 220         if (*idx < 0)
 221                 return;
 222         if (basic_rates & (1 << *idx))
 223                 return; /* selected rate is a basic rate */
 224
 225         for (i = *idx + 1; i <= sband->n_bitrates; i++) {
 226                 if (basic_rates & (1 << i)) {
 227                         *idx = i;
 228                         return;
 229                 }
 230         }
 231
 232         /* could not find a basic rate; use original selection */
 233 }
 234
 235 static void __rate_control_send_low(struct ieee80211_hw *hw,
 236                                     struct ieee80211_supported_band *sband,
 237                                     struct ieee80211_sta *sta,
 238                                     struct ieee80211_tx_info *info,
 239                                     u32 rate_mask)
 240 {
 241         int i;
 242         u32 rate_flags =
 243                 ieee80211_chandef_rate_flags(&hw->conf.chandef);
 244
 245         if ((sband->band == IEEE80211_BAND_2GHZ) &&
 246             (info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
 247                 rate_flags |= IEEE80211_RATE_ERP_G;
 248
 249         info->control.rates[0].idx = 0;
 250         for (i = 0; i < sband->n_bitrates; i++) {
 251                 if (!(rate_mask & BIT(i)))
 252                         continue;
 253
 254                 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
 255                         continue;
 256
 257                 if (!rate_supported(sta, sband->band, i))
 258                         continue;
 259
 260                 info->control.rates[0].idx = i;
 261                 break;
 262         }
 263         WARN_ON_ONCE(i == sband->n_bitrates);
 264
 265         info->control.rates[0].count =
 266                 (info->flags & IEEE80211_TX_CTL_NO_ACK) ?
 267                 1 : hw->max_rate_tries;
 268
 269         info->control.skip_table = 1;
 270 }
 271
 272
 273 bool rate_control_send_low(struct ieee80211_sta *pubsta,
 274                            void *priv_sta,
 275                            struct ieee80211_tx_rate_control *txrc)
 276 {
 277         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
 278         struct ieee80211_supported_band *sband = txrc->sband;
 279         struct sta_info *sta;
 280         int mcast_rate;
 281         bool use_basicrate = false;
 282
 283         if (!pubsta || !priv_sta || rc_no_data_or_no_ack_use_min(txrc)) {
 284                 __rate_control_send_low(txrc->hw, sband, pubsta, info,
 285                                         txrc->rate_idx_mask);
 286
 287                 if (!pubsta && txrc->bss) {
 288                         mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
 289                         if (mcast_rate > 0) {
 290                                 info->control.rates[0].idx = mcast_rate - 1;
 291                                 return true;
 292                         }
 293                         use_basicrate = true;
 294                 } else if (pubsta) {
 295                         sta = container_of(pubsta, struct sta_info, sta);
 296                         if (ieee80211_vif_is_mesh(&sta->sdata->vif))
 297                                 use_basicrate = true;
 298                 }
 299
 300                 if (use_basicrate)
 301                         rc_send_low_basicrate(&info->control.rates[0].idx,
 302                                               txrc->bss_conf->basic_rates,
 303                                               sband);
 304
 305                 return true;
 306         }
 307         return false;
 308 }
 309 EXPORT_SYMBOL(rate_control_send_low);
 310
 311 static bool rate_idx_match_legacy_mask(struct ieee80211_tx_rate *rate,
 312                                        int n_bitrates, u32 mask)
 313 {
 314         int j;
 315
 316         /* See whether the selected rate or anything below it is allowed. */
 317         for (j = rate->idx; j >= 0; j--) {
 318                 if (mask & (1 << j)) {
 319                         /* Okay, found a suitable rate. Use it. */
 320                         rate->idx = j;
 321                         return true;
 322                 }
 323         }
 324
 325         /* Try to find a higher rate that would be allowed */
 326         for (j = rate->idx + 1; j < n_bitrates; j++) {
 327                 if (mask & (1 << j)) {
 328                         /* Okay, found a suitable rate. Use it. */
 329                         rate->idx = j;
 330                         return true;
 331                 }
 332         }
 333         return false;
 334 }
 335
 336 static bool rate_idx_match_mcs_mask(struct ieee80211_tx_rate *rate,
 337                                     u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN])
 338 {
 339         int i, j;
 340         int ridx, rbit;
 341
 342         ridx = rate->idx / 8;
 343         rbit = rate->idx % 8;
 344
 345         /* sanity check */
 346         if (ridx < 0 || ridx >= IEEE80211_HT_MCS_MASK_LEN)
 347                 return false;
 348
 349         /* See whether the selected rate or anything below it is allowed. */
 350         for (i = ridx; i >= 0; i--) {
 351                 for (j = rbit; j >= 0; j--)
 352                         if (mcs_mask[i] & BIT(j)) {
 353                                 rate->idx = i * 8 + j;
 354                                 return true;
 355                         }
 356                 rbit = 7;
 357         }
 358
 359         /* Try to find a higher rate that would be allowed */
 360         ridx = (rate->idx + 1) / 8;
 361         rbit = (rate->idx + 1) % 8;
 362
 363         for (i = ridx; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
 364                 for (j = rbit; j < 8; j++)
 365                         if (mcs_mask[i] & BIT(j)) {
 366                                 rate->idx = i * 8 + j;
 367                                 return true;
 368                         }
 369                 rbit = 0;
 370         }
 371         return false;
 372 }
 373
 374
 375
 376 static void rate_idx_match_mask(struct ieee80211_tx_rate *rate,
 377                                 struct ieee80211_supported_band *sband,
 378                                 enum nl80211_chan_width chan_width,
 379                                 u32 mask,
 380                                 u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN])
 381 {
 382         struct ieee80211_tx_rate alt_rate;
 383
 384         /* handle HT rates */
 385         if (rate->flags & IEEE80211_TX_RC_MCS) {
 386                 if (rate_idx_match_mcs_mask(rate, mcs_mask))
 387                         return;
 388
 389                 /* also try the legacy rates. */
 390                 alt_rate.idx = 0;
 391                 /* keep protection flags */
 392                 alt_rate.flags = rate->flags &
 393                                  (IEEE80211_TX_RC_USE_RTS_CTS |
 394                                   IEEE80211_TX_RC_USE_CTS_PROTECT |
 395                                   IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
 396                 alt_rate.count = rate->count;
 397                 if (rate_idx_match_legacy_mask(&alt_rate,
 398                                                sband->n_bitrates, mask)) {
 399                         *rate = alt_rate;
 400                         return;
 401                 }
 402         } else {
 403                 /* handle legacy rates */
 404                 if (rate_idx_match_legacy_mask(rate, sband->n_bitrates, mask))
 405                         return;
 406
 407                 /* if HT BSS, and we handle a data frame, also try HT rates */
 408                 switch (chan_width) {
 409                 case NL80211_CHAN_WIDTH_20_NOHT:
 410                 case NL80211_CHAN_WIDTH_5:
 411                 case NL80211_CHAN_WIDTH_10:
 412                         return;
 413                 default:
 414                         break;
 415                 }
 416
 417                 alt_rate.idx = 0;
 418                 /* keep protection flags */
 419                 alt_rate.flags = rate->flags &
 420                                  (IEEE80211_TX_RC_USE_RTS_CTS |
 421                                   IEEE80211_TX_RC_USE_CTS_PROTECT |
 422                                   IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
 423                 alt_rate.count = rate->count;
 424
 425                 alt_rate.flags |= IEEE80211_TX_RC_MCS;
 426
 427                 if (chan_width == NL80211_CHAN_WIDTH_40)
 428                         alt_rate.flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
 429
 430                 if (rate_idx_match_mcs_mask(&alt_rate, mcs_mask)) {
 431                         *rate = alt_rate;
 432                         return;
 433                 }
 434         }
 435
 436         /*
 437          * Uh.. No suitable rate exists. This should not really happen with
 438          * sane TX rate mask configurations. However, should someone manage to
 439          * configure supported rates and TX rate mask in incompatible way,
 440          * allow the frame to be transmitted with whatever the rate control
 441          * selected.
 442          */
 443 }
 444
 445 static void rate_fixup_ratelist(struct ieee80211_vif *vif,
 446                                 struct ieee80211_supported_band *sband,
 447                                 struct ieee80211_tx_info *info,
 448                                 struct ieee80211_tx_rate *rates,
 449                                 int max_rates)
 450 {
 451         struct ieee80211_rate *rate;
 452         bool inval = false;
 453         int i;
 454
 455         /*
 456          * Set up the RTS/CTS rate as the fastest basic rate
 457          * that is not faster than the data rate unless there
 458          * is no basic rate slower than the data rate, in which
 459          * case we pick the slowest basic rate
 460          *
 461          * XXX: Should this check all retry rates?
 462          */
 463         if (!(rates[0].flags & IEEE80211_TX_RC_MCS)) {
 464                 u32 basic_rates = vif->bss_conf.basic_rates;
 465                 s8 baserate = basic_rates ? ffs(basic_rates - 1) : 0;
 466
 467                 rate = &sband->bitrates[rates[0].idx];
 468
 469                 for (i = 0; i < sband->n_bitrates; i++) {
 470                         /* must be a basic rate */
 471                         if (!(basic_rates & BIT(i)))
 472                                 continue;
 473                         /* must not be faster than the data rate */
 474                         if (sband->bitrates[i].bitrate > rate->bitrate)
 475                                 continue;
 476                         /* maximum */
 477                         if (sband->bitrates[baserate].bitrate <
 478                              sband->bitrates[i].bitrate)
 479                                 baserate = i;
 480                 }
 481
 482                 info->control.rts_cts_rate_idx = baserate;
 483         }
 484
 485         for (i = 0; i < max_rates; i++) {
 486                 /*
 487                  * make sure there's no valid rate following
 488                  * an invalid one, just in case drivers don't
 489                  * take the API seriously to stop at -1.
 490                  */
 491                 if (inval) {
 492                         rates[i].idx = -1;
 493                         continue;
 494                 }
 495                 if (rates[i].idx < 0) {
 496                         inval = true;
 497                         continue;
 498                 }
 499
 500                 /*
 501                  * For now assume MCS is already set up correctly, this
 502                  * needs to be fixed.
 503                  */
 504                 if (rates[i].flags & IEEE80211_TX_RC_MCS) {
 505                         WARN_ON(rates[i].idx > 76);
 506
 507                         if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
 508                             info->control.use_cts_prot)
 509                                 rates[i].flags |=
 510                                         IEEE80211_TX_RC_USE_CTS_PROTECT;
 511                         continue;
 512                 }
 513
 514                 if (rates[i].flags & IEEE80211_TX_RC_VHT_MCS) {
 515                         WARN_ON(ieee80211_rate_get_vht_mcs(&rates[i]) > 9);
 516                         continue;
 517                 }
 518
 519                 /* set up RTS protection if desired */
 520                 if (info->control.use_rts) {
 521                         rates[i].flags |= IEEE80211_TX_RC_USE_RTS_CTS;
 522                         info->control.use_cts_prot = false;
 523                 }
 524
 525                 /* RC is busted */
 526                 if (WARN_ON_ONCE(rates[i].idx >= sband->n_bitrates)) {
 527                         rates[i].idx = -1;
 528                         continue;
 529                 }
 530
 531                 rate = &sband->bitrates[rates[i].idx];
 532
 533                 /* set up short preamble */
 534                 if (info->control.short_preamble &&
 535                     rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
 536                         rates[i].flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
 537
 538                 /* set up G protection */
 539                 if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
 540                     info->control.use_cts_prot &&
 541                     rate->flags & IEEE80211_RATE_ERP_G)
 542                         rates[i].flags |= IEEE80211_TX_RC_USE_CTS_PROTECT;
 543         }
 544 }
 545
 546
 547 static void rate_control_fill_sta_table(struct ieee80211_sta *sta,
 548                                         struct ieee80211_tx_info *info,
 549                                         struct ieee80211_tx_rate *rates,
 550                                         int max_rates)
 551 {
 552         struct ieee80211_sta_rates *ratetbl = NULL;
 553         int i;
 554
 555         if (sta && !info->control.skip_table)
 556                 ratetbl = rcu_dereference(sta->rates);
 557
 558         /* Fill remaining rate slots with data from the sta rate table. */
 559         max_rates = min_t(int, max_rates, IEEE80211_TX_RATE_TABLE_SIZE);
 560         for (i = 0; i < max_rates; i++) {
 561                 if (i < ARRAY_SIZE(info->control.rates) &&
 562                     info->control.rates[i].idx >= 0 &&
 563                     info->control.rates[i].count) {
 564                         if (rates != info->control.rates)
 565                                 rates[i] = info->control.rates[i];
 566                 } else if (ratetbl) {
 567                         rates[i].idx = ratetbl->rate[i].idx;
 568                         rates[i].flags = ratetbl->rate[i].flags;
 569                         if (info->control.use_rts)
 570                                 rates[i].count = ratetbl->rate[i].count_rts;
 571                         else if (info->control.use_cts_prot)
 572                                 rates[i].count = ratetbl->rate[i].count_cts;
 573                         else
 574                                 rates[i].count = ratetbl->rate[i].count;
 575                 } else {
 576                         rates[i].idx = -1;
 577                         rates[i].count = 0;
 578                 }
 579
 580                 if (rates[i].idx < 0 || !rates[i].count)
 581                         break;
 582         }
 583 }
 584
 585 static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
 586                                     struct ieee80211_sta *sta,
 587                                     struct ieee80211_supported_band *sband,
 588                                     struct ieee80211_tx_info *info,
 589                                     struct ieee80211_tx_rate *rates,
 590                                     int max_rates)
 591 {
 592         enum nl80211_chan_width chan_width;
 593         u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
 594         bool has_mcs_mask;
 595         u32 mask;
 596         u32 rate_flags;
 597         int i;
 598
 599         /*
 600          * Try to enforce the rateidx mask the user wanted. skip this if the
 601          * default mask (allow all rates) is used to save some processing for
 602          * the common case.
 603          */
 604         mask = sdata->rc_rateidx_mask[info->band];
 605         has_mcs_mask = sdata->rc_has_mcs_mask[info->band];
 606         rate_flags =
 607                 ieee80211_chandef_rate_flags(&sdata->vif.bss_conf.chandef);
 608         for (i = 0; i < sband->n_bitrates; i++)
 609                 if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
 610                         mask &= ~BIT(i);
 611
 612         if (mask == (1 << sband->n_bitrates) - 1 && !has_mcs_mask)
 613                 return;
 614
 615         if (has_mcs_mask)
 616                 memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[info->band],
 617                        sizeof(mcs_mask));
 618         else
 619                 memset(mcs_mask, 0xff, sizeof(mcs_mask));
 620
 621         if (sta) {
 622                 /* Filter out rates that the STA does not support */
 623                 mask &= sta->supp_rates[info->band];
 624                 for (i = 0; i < sizeof(mcs_mask); i++)
 625                         mcs_mask[i] &= sta->ht_cap.mcs.rx_mask[i];
 626         }
 627
 628         /*
 629          * Make sure the rate index selected for each TX rate is
 630          * included in the configured mask and change the rate indexes
 631          * if needed.
 632          */
 633         chan_width = sdata->vif.bss_conf.chandef.width;
 634         for (i = 0; i < max_rates; i++) {
 635                 /* Skip invalid rates */
 636                 if (rates[i].idx < 0)
 637                         break;
 638
 639                 rate_idx_match_mask(&rates[i], sband, chan_width, mask,
 640                                     mcs_mask);
 641         }
 642 }
 643
 644 void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
 645                             struct ieee80211_sta *sta,
 646                             struct sk_buff *skb,
 647                             struct ieee80211_tx_rate *dest,
 648                             int max_rates)
 649 {
 650         struct ieee80211_sub_if_data *sdata;
 651         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 652         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 653         struct ieee80211_supported_band *sband;
 654
 655         rate_control_fill_sta_table(sta, info, dest, max_rates);
 656
 657         if (!vif)
 658                 return;
 659
 660         sdata = vif_to_sdata(vif);
 661         sband = sdata->local->hw.wiphy->bands[info->band];
 662
 663         if (ieee80211_is_data(hdr->frame_control))
 664                 rate_control_apply_mask(sdata, sta, sband, info, dest, max_rates);
 665
 666         if (dest[0].idx < 0)
 667                 __rate_control_send_low(&sdata->local->hw, sband, sta, info,
 668                                         sdata->rc_rateidx_mask[info->band]);
 669
 670         if (sta)
 671                 rate_fixup_ratelist(vif, sband, info, dest, max_rates);
 672 }
 673 EXPORT_SYMBOL(ieee80211_get_tx_rates);
 674
 675 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
 676                            struct sta_info *sta,
 677                            struct ieee80211_tx_rate_control *txrc)
 678 {
 679         struct rate_control_ref *ref = sdata->local->rate_ctrl;
 680         void *priv_sta = NULL;
 681         struct ieee80211_sta *ista = NULL;
 682         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
 683         int i;
 684
 685         if (sta && test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) {
 686                 ista = &sta->sta;
 687                 priv_sta = sta->rate_ctrl_priv;
 688         }
 689
 690         for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
 691                 info->control.rates[i].idx = -1;
 692                 info->control.rates[i].flags = 0;
 693                 info->control.rates[i].count = 0;
 694         }
 695
 696         if (sdata->local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL)
 697                 return;
 698
 699         ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
 700
 701         if (sdata->local->hw.flags & IEEE80211_HW_SUPPORTS_RC_TABLE)
 702                 return;
 703
 704         ieee80211_get_tx_rates(&sdata->vif, ista, txrc->skb,
 705                                info->control.rates,
 706                                ARRAY_SIZE(info->control.rates));
 707 }
 708
 709 int rate_control_set_rates(struct ieee80211_hw *hw,
 710                            struct ieee80211_sta *pubsta,
 711                            struct ieee80211_sta_rates *rates)
 712 {
 713         struct ieee80211_sta_rates *old;
 714
 715         /*
 716          * mac80211 guarantees that this function will not be called
 717          * concurrently, so the following RCU access is safe, even without
 718          * extra locking. This can not be checked easily, so we just set
 719          * the condition to true.
 720          */
 721         old = rcu_dereference_protected(pubsta->rates, true);
 722         rcu_assign_pointer(pubsta->rates, rates);
 723         if (old)
 724                 kfree_rcu(old, rcu_head);
 725
 726         return 0;
 727 }
 728 EXPORT_SYMBOL(rate_control_set_rates);
 729
 730 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
 731                                  const char *name)
 732 {
 733         struct rate_control_ref *ref;
 734
 735         ASSERT_RTNL();
 736
 737         if (local->open_count)
 738                 return -EBUSY;
 739
 740         if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) {
 741                 if (WARN_ON(!local->ops->set_rts_threshold))
 742                         return -EINVAL;
 743                 return 0;
 744         }
 745
 746         ref = rate_control_alloc(name, local);
 747         if (!ref) {
 748                 wiphy_warn(local->hw.wiphy,
 749                            "Failed to select rate control algorithm\n");
 750                 return -ENOENT;
 751         }
 752
 753         WARN_ON(local->rate_ctrl);
 754         local->rate_ctrl = ref;
 755
 756         wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n",
 757                     ref->ops->name);
 758
 759         return 0;
 760 }
 761
 762 void rate_control_deinitialize(struct ieee80211_local *local)
 763 {
 764         struct rate_control_ref *ref;
 765
 766         ref = local->rate_ctrl;
 767
 768         if (!ref)
 769                 return;
 770
 771         local->rate_ctrl = NULL;
 772         rate_control_free(ref);
 773 }
 774