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/slab.h>
  14#include <linux/module.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        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(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(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 struct rate_control_ops *
  80ieee80211_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. */
 101static struct rate_control_ops *
 102ieee80211_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
 130static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops)
 131{
 132        module_put(ops->module);
 133}
 134
 135#ifdef CONFIG_MAC80211_DEBUGFS
 136static 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
 146static const struct file_operations rcname_ops = {
 147        .read = rcname_read,
 148        .open = simple_open,
 149        .llseek = default_llseek,
 150};
 151#endif
 152
 153static 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
 178fail_priv:
 179        ieee80211_rate_control_ops_put(ref->ops);
 180fail_ops:
 181        kfree(ref);
 182fail_ref:
 183        return NULL;
 184}
 185
 186static 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
 199static 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
 213static 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
 235static 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{
 240        int i;
 241        u32 rate_flags =
 242                ieee80211_chandef_rate_flags(&hw->conf.chandef);
 243
 244        if ((sband->band == IEEE80211_BAND_2GHZ) &&
 245            (info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
 246                rate_flags |= IEEE80211_RATE_ERP_G;
 247
 248        info->control.rates[0].idx = 0;
 249        for (i = 0; i < sband->n_bitrates; i++) {
 250                if (!rate_supported(sta, sband->band, i))
 251                        continue;
 252
 253                info->control.rates[0].idx = i;
 254                break;
 255        }
 256        WARN_ON_ONCE(i == sband->n_bitrates);
 257
 258        info->control.rates[0].count =
 259                (info->flags & IEEE80211_TX_CTL_NO_ACK) ?
 260                1 : hw->max_rate_tries;
 261
 262        info->control.skip_table = 1;
 263}
 264
 265
 266bool rate_control_send_low(struct ieee80211_sta *pubsta,
 267                           void *priv_sta,
 268                           struct ieee80211_tx_rate_control *txrc)
 269{
 270        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
 271        struct ieee80211_supported_band *sband = txrc->sband;
 272        struct sta_info *sta;
 273        int mcast_rate;
 274        bool use_basicrate = false;
 275
 276        if (!pubsta || !priv_sta || rc_no_data_or_no_ack_use_min(txrc)) {
 277                __rate_control_send_low(txrc->hw, sband, pubsta, info);
 278
 279                if (!pubsta && txrc->bss) {
 280                        mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
 281                        if (mcast_rate > 0) {
 282                                info->control.rates[0].idx = mcast_rate - 1;
 283                                return true;
 284                        }
 285                        use_basicrate = true;
 286                } else if (pubsta) {
 287                        sta = container_of(pubsta, struct sta_info, sta);
 288                        if (ieee80211_vif_is_mesh(&sta->sdata->vif))
 289                                use_basicrate = true;
 290                }
 291
 292                if (use_basicrate)
 293                        rc_send_low_basicrate(&info->control.rates[0].idx,
 294                                              txrc->bss_conf->basic_rates,
 295                                              sband);
 296
 297                return true;
 298        }
 299        return false;
 300}
 301EXPORT_SYMBOL(rate_control_send_low);
 302
 303static 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
 328static 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
 368static 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
 437static 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
 539static 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
 577static 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        u32 rate_flags;
 589        int i;
 590
 591        /*
 592         * Try to enforce the rateidx mask the user wanted. skip this if the
 593         * default mask (allow all rates) is used to save some processing for
 594         * the common case.
 595         */
 596        mask = sdata->rc_rateidx_mask[info->band];
 597        has_mcs_mask = sdata->rc_has_mcs_mask[info->band];
 598        rate_flags =
 599                ieee80211_chandef_rate_flags(&sdata->vif.bss_conf.chandef);
 600        for (i = 0; i < sband->n_bitrates; i++)
 601                if ((rate_flags & sband->bitrates[i].flags) != rate_flags)
 602                        mask &= ~BIT(i);
 603
 604        if (mask == (1 << sband->n_bitrates) - 1 && !has_mcs_mask)
 605                return;
 606
 607        if (has_mcs_mask)
 608                memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[info->band],
 609                       sizeof(mcs_mask));
 610        else
 611                memset(mcs_mask, 0xff, sizeof(mcs_mask));
 612
 613        if (sta) {
 614                /* Filter out rates that the STA does not support */
 615                mask &= sta->supp_rates[info->band];
 616                for (i = 0; i < sizeof(mcs_mask); i++)
 617                        mcs_mask[i] &= sta->ht_cap.mcs.rx_mask[i];
 618        }
 619
 620        /*
 621         * Make sure the rate index selected for each TX rate is
 622         * included in the configured mask and change the rate indexes
 623         * if needed.
 624         */
 625        chan_width = sdata->vif.bss_conf.chandef.width;
 626        for (i = 0; i < max_rates; i++) {
 627                /* Skip invalid rates */
 628                if (rates[i].idx < 0)
 629                        break;
 630
 631                rate_idx_match_mask(&rates[i], sband, chan_width, mask,
 632                                    mcs_mask);
 633        }
 634}
 635
 636void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
 637                            struct ieee80211_sta *sta,
 638                            struct sk_buff *skb,
 639                            struct ieee80211_tx_rate *dest,
 640                            int max_rates)
 641{
 642        struct ieee80211_sub_if_data *sdata;
 643        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 644        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 645        struct ieee80211_supported_band *sband;
 646
 647        rate_control_fill_sta_table(sta, info, dest, max_rates);
 648
 649        if (!vif)
 650                return;
 651
 652        sdata = vif_to_sdata(vif);
 653        sband = sdata->local->hw.wiphy->bands[info->band];
 654
 655        if (ieee80211_is_data(hdr->frame_control))
 656                rate_control_apply_mask(sdata, sta, sband, info, dest, max_rates);
 657
 658        if (dest[0].idx < 0)
 659                __rate_control_send_low(&sdata->local->hw, sband, sta, info);
 660
 661        if (sta)
 662                rate_fixup_ratelist(vif, sband, info, dest, max_rates);
 663}
 664EXPORT_SYMBOL(ieee80211_get_tx_rates);
 665
 666void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
 667                           struct sta_info *sta,
 668                           struct ieee80211_tx_rate_control *txrc)
 669{
 670        struct rate_control_ref *ref = sdata->local->rate_ctrl;
 671        void *priv_sta = NULL;
 672        struct ieee80211_sta *ista = NULL;
 673        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
 674        int i;
 675
 676        if (sta && test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) {
 677                ista = &sta->sta;
 678                priv_sta = sta->rate_ctrl_priv;
 679        }
 680
 681        for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
 682                info->control.rates[i].idx = -1;
 683                info->control.rates[i].flags = 0;
 684                info->control.rates[i].count = 0;
 685        }
 686
 687        if (sdata->local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL)
 688                return;
 689
 690        ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
 691
 692        if (sdata->local->hw.flags & IEEE80211_HW_SUPPORTS_RC_TABLE)
 693                return;
 694
 695        ieee80211_get_tx_rates(&sdata->vif, ista, txrc->skb,
 696                               info->control.rates,
 697                               ARRAY_SIZE(info->control.rates));
 698}
 699
 700int rate_control_set_rates(struct ieee80211_hw *hw,
 701                           struct ieee80211_sta *pubsta,
 702                           struct ieee80211_sta_rates *rates)
 703{
 704        struct ieee80211_sta_rates *old;
 705
 706        /*
 707         * mac80211 guarantees that this function will not be called
 708         * concurrently, so the following RCU access is safe, even without
 709         * extra locking. This can not be checked easily, so we just set
 710         * the condition to true.
 711         */
 712        old = rcu_dereference_protected(pubsta->rates, true);
 713        rcu_assign_pointer(pubsta->rates, rates);
 714        if (old)
 715                kfree_rcu(old, rcu_head);
 716
 717        return 0;
 718}
 719EXPORT_SYMBOL(rate_control_set_rates);
 720
 721int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
 722                                 const char *name)
 723{
 724        struct rate_control_ref *ref;
 725
 726        ASSERT_RTNL();
 727
 728        if (local->open_count)
 729                return -EBUSY;
 730
 731        if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) {
 732                if (WARN_ON(!local->ops->set_rts_threshold))
 733                        return -EINVAL;
 734                return 0;
 735        }
 736
 737        ref = rate_control_alloc(name, local);
 738        if (!ref) {
 739                wiphy_warn(local->hw.wiphy,
 740                           "Failed to select rate control algorithm\n");
 741                return -ENOENT;
 742        }
 743
 744        WARN_ON(local->rate_ctrl);
 745        local->rate_ctrl = ref;
 746
 747        wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n",
 748                    ref->ops->name);
 749
 750        return 0;
 751}
 752
 753void rate_control_deinitialize(struct ieee80211_local *local)
 754{
 755        struct rate_control_ref *ref;
 756
 757        ref = local->rate_ctrl;
 758
 759        if (!ref)
 760                return;
 761
 762        local->rate_ctrl = NULL;
 763        rate_control_free(ref);
 764}
 765
 766