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_broadcast(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 inline s8
 236 rate_lowest_non_cck_index(struct ieee80211_supported_band *sband,
 237                           struct ieee80211_sta *sta)
 238 {
 239         int i;
 240
 241         for (i = 0; i < sband->n_bitrates; i++) {
 242                 struct ieee80211_rate *srate = &sband->bitrates[i];
 243                 if ((srate->bitrate == 10) || (srate->bitrate == 20) ||
 244                     (srate->bitrate == 55) || (srate->bitrate == 110))
 245                         continue;
 246
 247                 if (rate_supported(sta, sband->band, i))
 248                         return i;
 249         }
 250
 251         /* No matching rate found */
 252         return 0;
 253 }
 254
 255 static void __rate_control_send_low(struct ieee80211_hw *hw,
 256                                     struct ieee80211_supported_band *sband,
 257                                     struct ieee80211_sta *sta,
 258                                     struct ieee80211_tx_info *info)
 259 {
 260         if ((sband->band != IEEE80211_BAND_2GHZ) ||
 261             !(info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
 262                 info->control.rates[0].idx = rate_lowest_index(sband, sta);
 263         else
 264                 info->control.rates[0].idx =
 265                         rate_lowest_non_cck_index(sband, sta);
 266
 267         info->control.rates[0].count =
 268                 (info->flags & IEEE80211_TX_CTL_NO_ACK) ?
 269                 1 : hw->max_rate_tries;
 270
 271         info->control.skip_table = 1;
 272 }
 273
 274
 275 bool rate_control_send_low(struct ieee80211_sta *sta,
 276                            void *priv_sta,
 277                            struct ieee80211_tx_rate_control *txrc)
 278 {
 279         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
 280         struct ieee80211_supported_band *sband = txrc->sband;
 281         int mcast_rate;
 282
 283         if (!sta || !priv_sta || rc_no_data_or_no_ack_use_min(txrc)) {
 284                 __rate_control_send_low(txrc->hw, sband, sta, info);
 285
 286                 if (!sta && txrc->bss) {
 287                         mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
 288                         if (mcast_rate > 0) {
 289                                 info->control.rates[0].idx = mcast_rate - 1;
 290                                 return true;
 291                         }
 292
 293                         rc_send_low_broadcast(&info->control.rates[0].idx,
 294                                               txrc->bss_conf->basic_rates,
 295                                               sband);
 296                 }
 297                 return true;
 298         }
 299         return false;
 300 }
 301 EXPORT_SYMBOL(rate_control_send_low);
 302
 303 static bool rate_idx_match_legacy_mask(struct ieee80211_tx_rate *rate,
 304                                        int n_bitrates, u32 mask)
 305 {
 306         int j;
 307
 308         /* See whether the selected rate or anything below it is allowed. */
 309         for (j = rate->idx; j >= 0; j--) {
 310                 if (mask & (1 << j)) {
 311                         /* Okay, found a suitable rate. Use it. */
 312                         rate->idx = j;
 313                         return true;
 314                 }
 315         }
 316
 317         /* Try to find a higher rate that would be allowed */
 318         for (j = rate->idx + 1; j < n_bitrates; j++) {
 319                 if (mask & (1 << j)) {
 320                         /* Okay, found a suitable rate. Use it. */
 321                         rate->idx = j;
 322                         return true;
 323                 }
 324         }
 325         return false;
 326 }
 327
 328 static bool rate_idx_match_mcs_mask(struct ieee80211_tx_rate *rate,
 329                                     u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN])
 330 {
 331         int i, j;
 332         int ridx, rbit;
 333
 334         ridx = rate->idx / 8;
 335         rbit = rate->idx % 8;
 336
 337         /* sanity check */
 338         if (ridx < 0 || ridx >= IEEE80211_HT_MCS_MASK_LEN)
 339                 return false;
 340
 341         /* See whether the selected rate or anything below it is allowed. */
 342         for (i = ridx; i >= 0; i--) {
 343                 for (j = rbit; j >= 0; j--)
 344                         if (mcs_mask[i] & BIT(j)) {
 345                                 rate->idx = i * 8 + j;
 346                                 return true;
 347                         }
 348                 rbit = 7;
 349         }
 350
 351         /* Try to find a higher rate that would be allowed */
 352         ridx = (rate->idx + 1) / 8;
 353         rbit = (rate->idx + 1) % 8;
 354
 355         for (i = ridx; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
 356                 for (j = rbit; j < 8; j++)
 357                         if (mcs_mask[i] & BIT(j)) {
 358                                 rate->idx = i * 8 + j;
 359                                 return true;
 360                         }
 361                 rbit = 0;
 362         }
 363         return false;
 364 }
 365
 366
 367
 368 static void rate_idx_match_mask(struct ieee80211_tx_rate *rate,
 369                                 struct ieee80211_supported_band *sband,
 370                                 enum nl80211_chan_width chan_width,
 371                                 u32 mask,
 372                                 u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN])
 373 {
 374         struct ieee80211_tx_rate alt_rate;
 375
 376         /* handle HT rates */
 377         if (rate->flags & IEEE80211_TX_RC_MCS) {
 378                 if (rate_idx_match_mcs_mask(rate, mcs_mask))
 379                         return;
 380
 381                 /* also try the legacy rates. */
 382                 alt_rate.idx = 0;
 383                 /* keep protection flags */
 384                 alt_rate.flags = rate->flags &
 385                                  (IEEE80211_TX_RC_USE_RTS_CTS |
 386                                   IEEE80211_TX_RC_USE_CTS_PROTECT |
 387                                   IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
 388                 alt_rate.count = rate->count;
 389                 if (rate_idx_match_legacy_mask(&alt_rate,
 390                                                sband->n_bitrates, mask)) {
 391                         *rate = alt_rate;
 392                         return;
 393                 }
 394         } else {
 395                 /* handle legacy rates */
 396                 if (rate_idx_match_legacy_mask(rate, sband->n_bitrates, mask))
 397                         return;
 398
 399                 /* if HT BSS, and we handle a data frame, also try HT rates */
 400                 switch (chan_width) {
 401                 case NL80211_CHAN_WIDTH_20_NOHT:
 402                 case NL80211_CHAN_WIDTH_5:
 403                 case NL80211_CHAN_WIDTH_10:
 404                         return;
 405                 default:
 406                         break;
 407                 }
 408
 409                 alt_rate.idx = 0;
 410                 /* keep protection flags */
 411                 alt_rate.flags = rate->flags &
 412                                  (IEEE80211_TX_RC_USE_RTS_CTS |
 413                                   IEEE80211_TX_RC_USE_CTS_PROTECT |
 414                                   IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
 415                 alt_rate.count = rate->count;
 416
 417                 alt_rate.flags |= IEEE80211_TX_RC_MCS;
 418
 419                 if (chan_width == NL80211_CHAN_WIDTH_40)
 420                         alt_rate.flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
 421
 422                 if (rate_idx_match_mcs_mask(&alt_rate, mcs_mask)) {
 423                         *rate = alt_rate;
 424                         return;
 425                 }
 426         }
 427
 428         /*
 429          * Uh.. No suitable rate exists. This should not really happen with
 430          * sane TX rate mask configurations. However, should someone manage to
 431          * configure supported rates and TX rate mask in incompatible way,
 432          * allow the frame to be transmitted with whatever the rate control
 433          * selected.
 434          */
 435 }
 436
 437 static void rate_fixup_ratelist(struct ieee80211_vif *vif,
 438                                 struct ieee80211_supported_band *sband,
 439                                 struct ieee80211_tx_info *info,
 440                                 struct ieee80211_tx_rate *rates,
 441                                 int max_rates)
 442 {
 443         struct ieee80211_rate *rate;
 444         bool inval = false;
 445         int i;
 446
 447         /*
 448          * Set up the RTS/CTS rate as the fastest basic rate
 449          * that is not faster than the data rate unless there
 450          * is no basic rate slower than the data rate, in which
 451          * case we pick the slowest basic rate
 452          *
 453          * XXX: Should this check all retry rates?
 454          */
 455         if (!(rates[0].flags & IEEE80211_TX_RC_MCS)) {
 456                 u32 basic_rates = vif->bss_conf.basic_rates;
 457                 s8 baserate = basic_rates ? ffs(basic_rates - 1) : 0;
 458
 459                 rate = &sband->bitrates[rates[0].idx];
 460
 461                 for (i = 0; i < sband->n_bitrates; i++) {
 462                         /* must be a basic rate */
 463                         if (!(basic_rates & BIT(i)))
 464                                 continue;
 465                         /* must not be faster than the data rate */
 466                         if (sband->bitrates[i].bitrate > rate->bitrate)
 467                                 continue;
 468                         /* maximum */
 469                         if (sband->bitrates[baserate].bitrate <
 470                              sband->bitrates[i].bitrate)
 471                                 baserate = i;
 472                 }
 473
 474                 info->control.rts_cts_rate_idx = baserate;
 475         }
 476
 477         for (i = 0; i < max_rates; i++) {
 478                 /*
 479                  * make sure there's no valid rate following
 480                  * an invalid one, just in case drivers don't
 481                  * take the API seriously to stop at -1.
 482                  */
 483                 if (inval) {
 484                         rates[i].idx = -1;
 485                         continue;
 486                 }
 487                 if (rates[i].idx < 0) {
 488                         inval = true;
 489                         continue;
 490                 }
 491
 492                 /*
 493                  * For now assume MCS is already set up correctly, this
 494                  * needs to be fixed.
 495                  */
 496                 if (rates[i].flags & IEEE80211_TX_RC_MCS) {
 497                         WARN_ON(rates[i].idx > 76);
 498
 499                         if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
 500                             info->control.use_cts_prot)
 501                                 rates[i].flags |=
 502                                         IEEE80211_TX_RC_USE_CTS_PROTECT;
 503                         continue;
 504                 }
 505
 506                 if (rates[i].flags & IEEE80211_TX_RC_VHT_MCS) {
 507                         WARN_ON(ieee80211_rate_get_vht_mcs(&rates[i]) > 9);
 508                         continue;
 509                 }
 510
 511                 /* set up RTS protection if desired */
 512                 if (info->control.use_rts) {
 513                         rates[i].flags |= IEEE80211_TX_RC_USE_RTS_CTS;
 514                         info->control.use_cts_prot = false;
 515                 }
 516
 517                 /* RC is busted */
 518                 if (WARN_ON_ONCE(rates[i].idx >= sband->n_bitrates)) {
 519                         rates[i].idx = -1;
 520                         continue;
 521                 }
 522
 523                 rate = &sband->bitrates[rates[i].idx];
 524
 525                 /* set up short preamble */
 526                 if (info->control.short_preamble &&
 527                     rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
 528                         rates[i].flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
 529
 530                 /* set up G protection */
 531                 if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
 532                     info->control.use_cts_prot &&
 533                     rate->flags & IEEE80211_RATE_ERP_G)
 534                         rates[i].flags |= IEEE80211_TX_RC_USE_CTS_PROTECT;
 535         }
 536 }
 537
 538
 539 static void rate_control_fill_sta_table(struct ieee80211_sta *sta,
 540                                         struct ieee80211_tx_info *info,
 541                                         struct ieee80211_tx_rate *rates,
 542                                         int max_rates)
 543 {
 544         struct ieee80211_sta_rates *ratetbl = NULL;
 545         int i;
 546
 547         if (sta && !info->control.skip_table)
 548                 ratetbl = rcu_dereference(sta->rates);
 549
 550         /* Fill remaining rate slots with data from the sta rate table. */
 551         max_rates = min_t(int, max_rates, IEEE80211_TX_RATE_TABLE_SIZE);
 552         for (i = 0; i < max_rates; i++) {
 553                 if (i < ARRAY_SIZE(info->control.rates) &&
 554                     info->control.rates[i].idx >= 0 &&
 555                     info->control.rates[i].count) {
 556                         if (rates != info->control.rates)
 557                                 rates[i] = info->control.rates[i];
 558                 } else if (ratetbl) {
 559                         rates[i].idx = ratetbl->rate[i].idx;
 560                         rates[i].flags = ratetbl->rate[i].flags;
 561                         if (info->control.use_rts)
 562                                 rates[i].count = ratetbl->rate[i].count_rts;
 563                         else if (info->control.use_cts_prot)
 564                                 rates[i].count = ratetbl->rate[i].count_cts;
 565                         else
 566                                 rates[i].count = ratetbl->rate[i].count;
 567                 } else {
 568                         rates[i].idx = -1;
 569                         rates[i].count = 0;
 570                 }
 571
 572                 if (rates[i].idx < 0 || !rates[i].count)
 573                         break;
 574         }
 575 }
 576
 577 static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
 578                                     struct ieee80211_sta *sta,
 579                                     struct ieee80211_supported_band *sband,
 580                                     struct ieee80211_tx_info *info,
 581                                     struct ieee80211_tx_rate *rates,
 582                                     int max_rates)
 583 {
 584         enum nl80211_chan_width chan_width;
 585         u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
 586         bool has_mcs_mask;
 587         u32 mask;
 588         int i;
 589
 590         /*
 591          * Try to enforce the rateidx mask the user wanted. skip this if the
 592          * default mask (allow all rates) is used to save some processing for
 593          * the common case.
 594          */
 595         mask = sdata->rc_rateidx_mask[info->band];
 596         has_mcs_mask = sdata->rc_has_mcs_mask[info->band];
 597         if (mask == (1 << sband->n_bitrates) - 1 && !has_mcs_mask)
 598                 return;
 599
 600         if (has_mcs_mask)
 601                 memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[info->band],
 602                        sizeof(mcs_mask));
 603         else
 604                 memset(mcs_mask, 0xff, sizeof(mcs_mask));
 605
 606         if (sta) {
 607                 /* Filter out rates that the STA does not support */
 608                 mask &= sta->supp_rates[info->band];
 609                 for (i = 0; i < sizeof(mcs_mask); i++)
 610                         mcs_mask[i] &= sta->ht_cap.mcs.rx_mask[i];
 611         }
 612
 613         /*
 614          * Make sure the rate index selected for each TX rate is
 615          * included in the configured mask and change the rate indexes
 616          * if needed.
 617          */
 618         chan_width = sdata->vif.bss_conf.chandef.width;
 619         for (i = 0; i < max_rates; i++) {
 620                 /* Skip invalid rates */
 621                 if (rates[i].idx < 0)
 622                         break;
 623
 624                 rate_idx_match_mask(&rates[i], sband, chan_width, mask,
 625                                     mcs_mask);
 626         }
 627 }
 628
 629 void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
 630                             struct ieee80211_sta *sta,
 631                             struct sk_buff *skb,
 632                             struct ieee80211_tx_rate *dest,
 633                             int max_rates)
 634 {
 635         struct ieee80211_sub_if_data *sdata;
 636         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 637         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 638         struct ieee80211_supported_band *sband;
 639
 640         rate_control_fill_sta_table(sta, info, dest, max_rates);
 641
 642         if (!vif)
 643                 return;
 644
 645         sdata = vif_to_sdata(vif);
 646         sband = sdata->local->hw.wiphy->bands[info->band];
 647
 648         if (ieee80211_is_data(hdr->frame_control))
 649                 rate_control_apply_mask(sdata, sta, sband, info, dest, max_rates);
 650
 651         if (dest[0].idx < 0)
 652                 __rate_control_send_low(&sdata->local->hw, sband, sta, info);
 653
 654         if (sta)
 655                 rate_fixup_ratelist(vif, sband, info, dest, max_rates);
 656 }
 657 EXPORT_SYMBOL(ieee80211_get_tx_rates);
 658
 659 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
 660                            struct sta_info *sta,
 661                            struct ieee80211_tx_rate_control *txrc)
 662 {
 663         struct rate_control_ref *ref = sdata->local->rate_ctrl;
 664         void *priv_sta = NULL;
 665         struct ieee80211_sta *ista = NULL;
 666         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
 667         int i;
 668
 669         if (sta && test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) {
 670                 ista = &sta->sta;
 671                 priv_sta = sta->rate_ctrl_priv;
 672         }
 673
 674         for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
 675                 info->control.rates[i].idx = -1;
 676                 info->control.rates[i].flags = 0;
 677                 info->control.rates[i].count = 0;
 678         }
 679
 680         if (sdata->local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL)
 681                 return;
 682
 683         ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
 684
 685         if (sdata->local->hw.flags & IEEE80211_HW_SUPPORTS_RC_TABLE)
 686                 return;
 687
 688         ieee80211_get_tx_rates(&sdata->vif, ista, txrc->skb,
 689                                info->control.rates,
 690                                ARRAY_SIZE(info->control.rates));
 691 }
 692
 693 int rate_control_set_rates(struct ieee80211_hw *hw,
 694                            struct ieee80211_sta *pubsta,
 695                            struct ieee80211_sta_rates *rates)
 696 {
 697         struct ieee80211_sta_rates *old;
 698
 699         /*
 700          * mac80211 guarantees that this function will not be called
 701          * concurrently, so the following RCU access is safe, even without
 702          * extra locking. This can not be checked easily, so we just set
 703          * the condition to true.
 704          */
 705         old = rcu_dereference_protected(pubsta->rates, true);
 706         rcu_assign_pointer(pubsta->rates, rates);
 707         if (old)
 708                 kfree_rcu(old, rcu_head);
 709
 710         return 0;
 711 }
 712 EXPORT_SYMBOL(rate_control_set_rates);
 713
 714 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
 715                                  const char *name)
 716 {
 717         struct rate_control_ref *ref;
 718
 719         ASSERT_RTNL();
 720
 721         if (local->open_count)
 722                 return -EBUSY;
 723
 724         if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) {
 725                 if (WARN_ON(!local->ops->set_rts_threshold))
 726                         return -EINVAL;
 727                 return 0;
 728         }
 729
 730         ref = rate_control_alloc(name, local);
 731         if (!ref) {
 732                 wiphy_warn(local->hw.wiphy,
 733                            "Failed to select rate control algorithm\n");
 734                 return -ENOENT;
 735         }
 736
 737         WARN_ON(local->rate_ctrl);
 738         local->rate_ctrl = ref;
 739
 740         wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n",
 741                     ref->ops->name);
 742
 743         return 0;
 744 }
 745
 746 void rate_control_deinitialize(struct ieee80211_local *local)
 747 {
 748         struct rate_control_ref *ref;
 749
 750         ref = local->rate_ctrl;
 751
 752         if (!ref)
 753                 return;
 754
 755         local->rate_ctrl = NULL;
 756         rate_control_free(ref);
 757 }
 758