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