linux/net/mac80211/rate.c
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   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
  19struct rate_control_alg {
  20        struct list_head list;
  21        const struct rate_control_ops *ops;
  22};
  23
  24static LIST_HEAD(rate_ctrl_algs);
  25static DEFINE_MUTEX(rate_ctrl_mutex);
  26
  27static char *ieee80211_default_rc_algo = CONFIG_MAC80211_RC_DEFAULT;
  28module_param(ieee80211_default_rc_algo, charp, 0644);
  29MODULE_PARM_DESC(ieee80211_default_rc_algo,
  30                 "Default rate control algorithm for mac80211 to use");
  31
  32int 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}
  61EXPORT_SYMBOL(ieee80211_rate_control_register);
  62
  63void 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}
  77EXPORT_SYMBOL(ieee80211_rate_control_unregister);
  78
  79static const struct rate_control_ops *
  80ieee80211_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. */
 100static const struct rate_control_ops *
 101ieee80211_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
 126static 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
 136static const struct file_operations rcname_ops = {
 137        .read = rcname_read,
 138        .open = simple_open,
 139        .llseek = default_llseek,
 140};
 141#endif
 142
 143static 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
 168free:
 169        kfree(ref);
 170        return NULL;
 171}
 172
 173static 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
 185static 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
 199static 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
 221static 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
 259bool 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}
 295EXPORT_SYMBOL(rate_control_send_low);
 296
 297static 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
 322static 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
 362static 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
 431static 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
 533static 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
 571static 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
 630void 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}
 659EXPORT_SYMBOL(ieee80211_get_tx_rates);
 660
 661void 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
 695int 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}
 714EXPORT_SYMBOL(rate_control_set_rates);
 715
 716int 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
 748void 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
 761