linux/net/mac80211/agg-tx.c
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   1/*
   2 * HT handling
   3 *
   4 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   5 * Copyright 2002-2005, Instant802 Networks, Inc.
   6 * Copyright 2005-2006, Devicescape Software, Inc.
   7 * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   8 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
   9 * Copyright 2007-2010, Intel Corporation
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License version 2 as
  13 * published by the Free Software Foundation.
  14 */
  15
  16#include <linux/ieee80211.h>
  17#include <linux/slab.h>
  18#include <linux/export.h>
  19#include <net/mac80211.h>
  20#include "ieee80211_i.h"
  21#include "driver-ops.h"
  22#include "wme.h"
  23
  24/**
  25 * DOC: TX A-MPDU aggregation
  26 *
  27 * Aggregation on the TX side requires setting the hardware flag
  28 * %IEEE80211_HW_AMPDU_AGGREGATION. The driver will then be handed
  29 * packets with a flag indicating A-MPDU aggregation. The driver
  30 * or device is responsible for actually aggregating the frames,
  31 * as well as deciding how many and which to aggregate.
  32 *
  33 * When TX aggregation is started by some subsystem (usually the rate
  34 * control algorithm would be appropriate) by calling the
  35 * ieee80211_start_tx_ba_session() function, the driver will be
  36 * notified via its @ampdu_action function, with the
  37 * %IEEE80211_AMPDU_TX_START action.
  38 *
  39 * In response to that, the driver is later required to call the
  40 * ieee80211_start_tx_ba_cb_irqsafe() function, which will really
  41 * start the aggregation session after the peer has also responded.
  42 * If the peer responds negatively, the session will be stopped
  43 * again right away. Note that it is possible for the aggregation
  44 * session to be stopped before the driver has indicated that it
  45 * is done setting it up, in which case it must not indicate the
  46 * setup completion.
  47 *
  48 * Also note that, since we also need to wait for a response from
  49 * the peer, the driver is notified of the completion of the
  50 * handshake by the %IEEE80211_AMPDU_TX_OPERATIONAL action to the
  51 * @ampdu_action callback.
  52 *
  53 * Similarly, when the aggregation session is stopped by the peer
  54 * or something calling ieee80211_stop_tx_ba_session(), the driver's
  55 * @ampdu_action function will be called with the action
  56 * %IEEE80211_AMPDU_TX_STOP. In this case, the call must not fail,
  57 * and the driver must later call ieee80211_stop_tx_ba_cb_irqsafe().
  58 * Note that the sta can get destroyed before the BA tear down is
  59 * complete.
  60 */
  61
  62static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,
  63                                         const u8 *da, u16 tid,
  64                                         u8 dialog_token, u16 start_seq_num,
  65                                         u16 agg_size, u16 timeout)
  66{
  67        struct ieee80211_local *local = sdata->local;
  68        struct sk_buff *skb;
  69        struct ieee80211_mgmt *mgmt;
  70        u16 capab;
  71
  72        skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
  73
  74        if (!skb)
  75                return;
  76
  77        skb_reserve(skb, local->hw.extra_tx_headroom);
  78        mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
  79        memset(mgmt, 0, 24);
  80        memcpy(mgmt->da, da, ETH_ALEN);
  81        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
  82        if (sdata->vif.type == NL80211_IFTYPE_AP ||
  83            sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
  84            sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
  85                memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
  86        else if (sdata->vif.type == NL80211_IFTYPE_STATION)
  87                memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
  88        else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
  89                memcpy(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN);
  90
  91        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  92                                          IEEE80211_STYPE_ACTION);
  93
  94        skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
  95
  96        mgmt->u.action.category = WLAN_CATEGORY_BACK;
  97        mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
  98
  99        mgmt->u.action.u.addba_req.dialog_token = dialog_token;
 100        capab = (u16)(1 << 0);          /* bit 0 A-MSDU support */
 101        capab |= (u16)(1 << 1);         /* bit 1 aggregation policy */
 102        capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
 103        capab |= (u16)(agg_size << 6);  /* bit 15:6 max size of aggergation */
 104
 105        mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
 106
 107        mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
 108        mgmt->u.action.u.addba_req.start_seq_num =
 109                                        cpu_to_le16(start_seq_num << 4);
 110
 111        ieee80211_tx_skb(sdata, skb);
 112}
 113
 114void ieee80211_send_bar(struct ieee80211_vif *vif, u8 *ra, u16 tid, u16 ssn)
 115{
 116        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 117        struct ieee80211_local *local = sdata->local;
 118        struct sk_buff *skb;
 119        struct ieee80211_bar *bar;
 120        u16 bar_control = 0;
 121
 122        skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
 123        if (!skb)
 124                return;
 125
 126        skb_reserve(skb, local->hw.extra_tx_headroom);
 127        bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar));
 128        memset(bar, 0, sizeof(*bar));
 129        bar->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
 130                                         IEEE80211_STYPE_BACK_REQ);
 131        memcpy(bar->ra, ra, ETH_ALEN);
 132        memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
 133        bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
 134        bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
 135        bar_control |= (u16)(tid << IEEE80211_BAR_CTRL_TID_INFO_SHIFT);
 136        bar->control = cpu_to_le16(bar_control);
 137        bar->start_seq_num = cpu_to_le16(ssn);
 138
 139        IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT |
 140                                        IEEE80211_TX_CTL_REQ_TX_STATUS;
 141        ieee80211_tx_skb_tid(sdata, skb, tid);
 142}
 143EXPORT_SYMBOL(ieee80211_send_bar);
 144
 145void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
 146                             struct tid_ampdu_tx *tid_tx)
 147{
 148        lockdep_assert_held(&sta->ampdu_mlme.mtx);
 149        lockdep_assert_held(&sta->lock);
 150        rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);
 151}
 152
 153/*
 154 * When multiple aggregation sessions on multiple stations
 155 * are being created/destroyed simultaneously, we need to
 156 * refcount the global queue stop caused by that in order
 157 * to not get into a situation where one of the aggregation
 158 * setup or teardown re-enables queues before the other is
 159 * ready to handle that.
 160 *
 161 * These two functions take care of this issue by keeping
 162 * a global "agg_queue_stop" refcount.
 163 */
 164static void __acquires(agg_queue)
 165ieee80211_stop_queue_agg(struct ieee80211_sub_if_data *sdata, int tid)
 166{
 167        int queue = sdata->vif.hw_queue[ieee80211_ac_from_tid(tid)];
 168
 169        /* we do refcounting here, so don't use the queue reason refcounting */
 170
 171        if (atomic_inc_return(&sdata->local->agg_queue_stop[queue]) == 1)
 172                ieee80211_stop_queue_by_reason(
 173                        &sdata->local->hw, queue,
 174                        IEEE80211_QUEUE_STOP_REASON_AGGREGATION,
 175                        false);
 176        __acquire(agg_queue);
 177}
 178
 179static void __releases(agg_queue)
 180ieee80211_wake_queue_agg(struct ieee80211_sub_if_data *sdata, int tid)
 181{
 182        int queue = sdata->vif.hw_queue[ieee80211_ac_from_tid(tid)];
 183
 184        if (atomic_dec_return(&sdata->local->agg_queue_stop[queue]) == 0)
 185                ieee80211_wake_queue_by_reason(
 186                        &sdata->local->hw, queue,
 187                        IEEE80211_QUEUE_STOP_REASON_AGGREGATION,
 188                        false);
 189        __release(agg_queue);
 190}
 191
 192static void
 193ieee80211_agg_stop_txq(struct sta_info *sta, int tid)
 194{
 195        struct ieee80211_txq *txq = sta->sta.txq[tid];
 196        struct txq_info *txqi;
 197
 198        if (!txq)
 199                return;
 200
 201        txqi = to_txq_info(txq);
 202
 203        /* Lock here to protect against further seqno updates on dequeue */
 204        spin_lock_bh(&txqi->queue.lock);
 205        set_bit(IEEE80211_TXQ_STOP, &txqi->flags);
 206        spin_unlock_bh(&txqi->queue.lock);
 207}
 208
 209static void
 210ieee80211_agg_start_txq(struct sta_info *sta, int tid, bool enable)
 211{
 212        struct ieee80211_txq *txq = sta->sta.txq[tid];
 213        struct txq_info *txqi;
 214
 215        if (!txq)
 216                return;
 217
 218        txqi = to_txq_info(txq);
 219
 220        if (enable)
 221                set_bit(IEEE80211_TXQ_AMPDU, &txqi->flags);
 222        else
 223                clear_bit(IEEE80211_TXQ_AMPDU, &txqi->flags);
 224
 225        clear_bit(IEEE80211_TXQ_STOP, &txqi->flags);
 226        drv_wake_tx_queue(sta->sdata->local, txqi);
 227}
 228
 229/*
 230 * splice packets from the STA's pending to the local pending,
 231 * requires a call to ieee80211_agg_splice_finish later
 232 */
 233static void __acquires(agg_queue)
 234ieee80211_agg_splice_packets(struct ieee80211_sub_if_data *sdata,
 235                             struct tid_ampdu_tx *tid_tx, u16 tid)
 236{
 237        struct ieee80211_local *local = sdata->local;
 238        int queue = sdata->vif.hw_queue[ieee80211_ac_from_tid(tid)];
 239        unsigned long flags;
 240
 241        ieee80211_stop_queue_agg(sdata, tid);
 242
 243        if (WARN(!tid_tx,
 244                 "TID %d gone but expected when splicing aggregates from the pending queue\n",
 245                 tid))
 246                return;
 247
 248        if (!skb_queue_empty(&tid_tx->pending)) {
 249                spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 250                /* copy over remaining packets */
 251                skb_queue_splice_tail_init(&tid_tx->pending,
 252                                           &local->pending[queue]);
 253                spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 254        }
 255}
 256
 257static void __releases(agg_queue)
 258ieee80211_agg_splice_finish(struct ieee80211_sub_if_data *sdata, u16 tid)
 259{
 260        ieee80211_wake_queue_agg(sdata, tid);
 261}
 262
 263static void ieee80211_remove_tid_tx(struct sta_info *sta, int tid)
 264{
 265        struct tid_ampdu_tx *tid_tx;
 266
 267        lockdep_assert_held(&sta->ampdu_mlme.mtx);
 268        lockdep_assert_held(&sta->lock);
 269
 270        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 271
 272        /*
 273         * When we get here, the TX path will not be lockless any more wrt.
 274         * aggregation, since the OPERATIONAL bit has long been cleared.
 275         * Thus it will block on getting the lock, if it occurs. So if we
 276         * stop the queue now, we will not get any more packets, and any
 277         * that might be being processed will wait for us here, thereby
 278         * guaranteeing that no packets go to the tid_tx pending queue any
 279         * more.
 280         */
 281
 282        ieee80211_agg_splice_packets(sta->sdata, tid_tx, tid);
 283
 284        /* future packets must not find the tid_tx struct any more */
 285        ieee80211_assign_tid_tx(sta, tid, NULL);
 286
 287        ieee80211_agg_splice_finish(sta->sdata, tid);
 288        ieee80211_agg_start_txq(sta, tid, false);
 289
 290        kfree_rcu(tid_tx, rcu_head);
 291}
 292
 293int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 294                                    enum ieee80211_agg_stop_reason reason)
 295{
 296        struct ieee80211_local *local = sta->local;
 297        struct tid_ampdu_tx *tid_tx;
 298        enum ieee80211_ampdu_mlme_action action;
 299        int ret;
 300
 301        lockdep_assert_held(&sta->ampdu_mlme.mtx);
 302
 303        switch (reason) {
 304        case AGG_STOP_DECLINED:
 305        case AGG_STOP_LOCAL_REQUEST:
 306        case AGG_STOP_PEER_REQUEST:
 307                action = IEEE80211_AMPDU_TX_STOP_CONT;
 308                break;
 309        case AGG_STOP_DESTROY_STA:
 310                action = IEEE80211_AMPDU_TX_STOP_FLUSH;
 311                break;
 312        default:
 313                WARN_ON_ONCE(1);
 314                return -EINVAL;
 315        }
 316
 317        spin_lock_bh(&sta->lock);
 318
 319        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 320        if (!tid_tx) {
 321                spin_unlock_bh(&sta->lock);
 322                return -ENOENT;
 323        }
 324
 325        /*
 326         * if we're already stopping ignore any new requests to stop
 327         * unless we're destroying it in which case notify the driver
 328         */
 329        if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 330                spin_unlock_bh(&sta->lock);
 331                if (reason != AGG_STOP_DESTROY_STA)
 332                        return -EALREADY;
 333                ret = drv_ampdu_action(local, sta->sdata,
 334                                       IEEE80211_AMPDU_TX_STOP_FLUSH_CONT,
 335                                       &sta->sta, tid, NULL, 0, false);
 336                WARN_ON_ONCE(ret);
 337                return 0;
 338        }
 339
 340        if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
 341                /* not even started yet! */
 342                ieee80211_assign_tid_tx(sta, tid, NULL);
 343                spin_unlock_bh(&sta->lock);
 344                kfree_rcu(tid_tx, rcu_head);
 345                return 0;
 346        }
 347
 348        set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);
 349
 350        spin_unlock_bh(&sta->lock);
 351
 352        ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
 353               sta->sta.addr, tid);
 354
 355        del_timer_sync(&tid_tx->addba_resp_timer);
 356        del_timer_sync(&tid_tx->session_timer);
 357
 358        /*
 359         * After this packets are no longer handed right through
 360         * to the driver but are put onto tid_tx->pending instead,
 361         * with locking to ensure proper access.
 362         */
 363        clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 364
 365        /*
 366         * There might be a few packets being processed right now (on
 367         * another CPU) that have already gotten past the aggregation
 368         * check when it was still OPERATIONAL and consequently have
 369         * IEEE80211_TX_CTL_AMPDU set. In that case, this code might
 370         * call into the driver at the same time or even before the
 371         * TX paths calls into it, which could confuse the driver.
 372         *
 373         * Wait for all currently running TX paths to finish before
 374         * telling the driver. New packets will not go through since
 375         * the aggregation session is no longer OPERATIONAL.
 376         */
 377        synchronize_net();
 378
 379        tid_tx->stop_initiator = reason == AGG_STOP_PEER_REQUEST ?
 380                                        WLAN_BACK_RECIPIENT :
 381                                        WLAN_BACK_INITIATOR;
 382        tid_tx->tx_stop = reason == AGG_STOP_LOCAL_REQUEST;
 383
 384        ret = drv_ampdu_action(local, sta->sdata, action,
 385                               &sta->sta, tid, NULL, 0, false);
 386
 387        /* HW shall not deny going back to legacy */
 388        if (WARN_ON(ret)) {
 389                /*
 390                 * We may have pending packets get stuck in this case...
 391                 * Not bothering with a workaround for now.
 392                 */
 393        }
 394
 395        /*
 396         * In the case of AGG_STOP_DESTROY_STA, the driver won't
 397         * necessarily call ieee80211_stop_tx_ba_cb(), so this may
 398         * seem like we can leave the tid_tx data pending forever.
 399         * This is true, in a way, but "forever" is only until the
 400         * station struct is actually destroyed. In the meantime,
 401         * leaving it around ensures that we don't transmit packets
 402         * to the driver on this TID which might confuse it.
 403         */
 404
 405        return 0;
 406}
 407
 408/*
 409 * After sending add Block Ack request we activated a timer until
 410 * add Block Ack response will arrive from the recipient.
 411 * If this timer expires sta_addba_resp_timer_expired will be executed.
 412 */
 413static void sta_addba_resp_timer_expired(unsigned long data)
 414{
 415        /* not an elegant detour, but there is no choice as the timer passes
 416         * only one argument, and both sta_info and TID are needed, so init
 417         * flow in sta_info_create gives the TID as data, while the timer_to_id
 418         * array gives the sta through container_of */
 419        u16 tid = *(u8 *)data;
 420        struct sta_info *sta = container_of((void *)data,
 421                struct sta_info, timer_to_tid[tid]);
 422        struct tid_ampdu_tx *tid_tx;
 423
 424        /* check if the TID waits for addBA response */
 425        rcu_read_lock();
 426        tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 427        if (!tid_tx ||
 428            test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
 429                rcu_read_unlock();
 430                ht_dbg(sta->sdata,
 431                       "timer expired on %pM tid %d but we are not (or no longer) expecting addBA response there\n",
 432                       sta->sta.addr, tid);
 433                return;
 434        }
 435
 436        ht_dbg(sta->sdata, "addBA response timer expired on %pM tid %d\n",
 437               sta->sta.addr, tid);
 438
 439        ieee80211_stop_tx_ba_session(&sta->sta, tid);
 440        rcu_read_unlock();
 441}
 442
 443void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 444{
 445        struct tid_ampdu_tx *tid_tx;
 446        struct ieee80211_local *local = sta->local;
 447        struct ieee80211_sub_if_data *sdata = sta->sdata;
 448        u16 start_seq_num;
 449        int ret;
 450
 451        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 452
 453        /*
 454         * Start queuing up packets for this aggregation session.
 455         * We're going to release them once the driver is OK with
 456         * that.
 457         */
 458        clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 459
 460        ieee80211_agg_stop_txq(sta, tid);
 461
 462        /*
 463         * Make sure no packets are being processed. This ensures that
 464         * we have a valid starting sequence number and that in-flight
 465         * packets have been flushed out and no packets for this TID
 466         * will go into the driver during the ampdu_action call.
 467         */
 468        synchronize_net();
 469
 470        start_seq_num = sta->tid_seq[tid] >> 4;
 471
 472        ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START,
 473                               &sta->sta, tid, &start_seq_num, 0, false);
 474        if (ret) {
 475                ht_dbg(sdata,
 476                       "BA request denied - HW unavailable for %pM tid %d\n",
 477                       sta->sta.addr, tid);
 478                spin_lock_bh(&sta->lock);
 479                ieee80211_agg_splice_packets(sdata, tid_tx, tid);
 480                ieee80211_assign_tid_tx(sta, tid, NULL);
 481                ieee80211_agg_splice_finish(sdata, tid);
 482                spin_unlock_bh(&sta->lock);
 483
 484                ieee80211_agg_start_txq(sta, tid, false);
 485
 486                kfree_rcu(tid_tx, rcu_head);
 487                return;
 488        }
 489
 490        /* activate the timer for the recipient's addBA response */
 491        mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
 492        ht_dbg(sdata, "activated addBA response timer on %pM tid %d\n",
 493               sta->sta.addr, tid);
 494
 495        spin_lock_bh(&sta->lock);
 496        sta->ampdu_mlme.last_addba_req_time[tid] = jiffies;
 497        sta->ampdu_mlme.addba_req_num[tid]++;
 498        spin_unlock_bh(&sta->lock);
 499
 500        /* send AddBA request */
 501        ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
 502                                     tid_tx->dialog_token, start_seq_num,
 503                                     IEEE80211_MAX_AMPDU_BUF,
 504                                     tid_tx->timeout);
 505}
 506
 507/*
 508 * After accepting the AddBA Response we activated a timer,
 509 * resetting it after each frame that we send.
 510 */
 511static void sta_tx_agg_session_timer_expired(unsigned long data)
 512{
 513        /* not an elegant detour, but there is no choice as the timer passes
 514         * only one argument, and various sta_info are needed here, so init
 515         * flow in sta_info_create gives the TID as data, while the timer_to_id
 516         * array gives the sta through container_of */
 517        u8 *ptid = (u8 *)data;
 518        u8 *timer_to_id = ptid - *ptid;
 519        struct sta_info *sta = container_of(timer_to_id, struct sta_info,
 520                                         timer_to_tid[0]);
 521        struct tid_ampdu_tx *tid_tx;
 522        unsigned long timeout;
 523
 524        rcu_read_lock();
 525        tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[*ptid]);
 526        if (!tid_tx || test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 527                rcu_read_unlock();
 528                return;
 529        }
 530
 531        timeout = tid_tx->last_tx + TU_TO_JIFFIES(tid_tx->timeout);
 532        if (time_is_after_jiffies(timeout)) {
 533                mod_timer(&tid_tx->session_timer, timeout);
 534                rcu_read_unlock();
 535                return;
 536        }
 537
 538        rcu_read_unlock();
 539
 540        ht_dbg(sta->sdata, "tx session timer expired on %pM tid %d\n",
 541               sta->sta.addr, (u16)*ptid);
 542
 543        ieee80211_stop_tx_ba_session(&sta->sta, *ptid);
 544}
 545
 546int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
 547                                  u16 timeout)
 548{
 549        struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 550        struct ieee80211_sub_if_data *sdata = sta->sdata;
 551        struct ieee80211_local *local = sdata->local;
 552        struct tid_ampdu_tx *tid_tx;
 553        int ret = 0;
 554
 555        trace_api_start_tx_ba_session(pubsta, tid);
 556
 557        if (WARN(sta->reserved_tid == tid,
 558                 "Requested to start BA session on reserved tid=%d", tid))
 559                return -EINVAL;
 560
 561        if (!pubsta->ht_cap.ht_supported)
 562                return -EINVAL;
 563
 564        if (WARN_ON_ONCE(!local->ops->ampdu_action))
 565                return -EINVAL;
 566
 567        if ((tid >= IEEE80211_NUM_TIDS) ||
 568            !ieee80211_hw_check(&local->hw, AMPDU_AGGREGATION) ||
 569            ieee80211_hw_check(&local->hw, TX_AMPDU_SETUP_IN_HW))
 570                return -EINVAL;
 571
 572        ht_dbg(sdata, "Open BA session requested for %pM tid %u\n",
 573               pubsta->addr, tid);
 574
 575        if (sdata->vif.type != NL80211_IFTYPE_STATION &&
 576            sdata->vif.type != NL80211_IFTYPE_MESH_POINT &&
 577            sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
 578            sdata->vif.type != NL80211_IFTYPE_AP &&
 579            sdata->vif.type != NL80211_IFTYPE_ADHOC)
 580                return -EINVAL;
 581
 582        if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
 583                ht_dbg(sdata,
 584                       "BA sessions blocked - Denying BA session request %pM tid %d\n",
 585                       sta->sta.addr, tid);
 586                return -EINVAL;
 587        }
 588
 589        /*
 590         * 802.11n-2009 11.5.1.1: If the initiating STA is an HT STA, is a
 591         * member of an IBSS, and has no other existing Block Ack agreement
 592         * with the recipient STA, then the initiating STA shall transmit a
 593         * Probe Request frame to the recipient STA and shall not transmit an
 594         * ADDBA Request frame unless it receives a Probe Response frame
 595         * from the recipient within dot11ADDBAFailureTimeout.
 596         *
 597         * The probe request mechanism for ADDBA is currently not implemented,
 598         * but we only build up Block Ack session with HT STAs. This information
 599         * is set when we receive a bss info from a probe response or a beacon.
 600         */
 601        if (sta->sdata->vif.type == NL80211_IFTYPE_ADHOC &&
 602            !sta->sta.ht_cap.ht_supported) {
 603                ht_dbg(sdata,
 604                       "BA request denied - IBSS STA %pM does not advertise HT support\n",
 605                       pubsta->addr);
 606                return -EINVAL;
 607        }
 608
 609        spin_lock_bh(&sta->lock);
 610
 611        /* we have tried too many times, receiver does not want A-MPDU */
 612        if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
 613                ret = -EBUSY;
 614                goto err_unlock_sta;
 615        }
 616
 617        /*
 618         * if we have tried more than HT_AGG_BURST_RETRIES times we
 619         * will spread our requests in time to avoid stalling connection
 620         * for too long
 621         */
 622        if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_BURST_RETRIES &&
 623            time_before(jiffies, sta->ampdu_mlme.last_addba_req_time[tid] +
 624                        HT_AGG_RETRIES_PERIOD)) {
 625                ht_dbg(sdata,
 626                       "BA request denied - waiting a grace period after %d failed requests on %pM tid %u\n",
 627                       sta->ampdu_mlme.addba_req_num[tid], sta->sta.addr, tid);
 628                ret = -EBUSY;
 629                goto err_unlock_sta;
 630        }
 631
 632        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 633        /* check if the TID is not in aggregation flow already */
 634        if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
 635                ht_dbg(sdata,
 636                       "BA request denied - session is not idle on %pM tid %u\n",
 637                       sta->sta.addr, tid);
 638                ret = -EAGAIN;
 639                goto err_unlock_sta;
 640        }
 641
 642        /* prepare A-MPDU MLME for Tx aggregation */
 643        tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
 644        if (!tid_tx) {
 645                ret = -ENOMEM;
 646                goto err_unlock_sta;
 647        }
 648
 649        skb_queue_head_init(&tid_tx->pending);
 650        __set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 651
 652        tid_tx->timeout = timeout;
 653
 654        /* response timer */
 655        tid_tx->addba_resp_timer.function = sta_addba_resp_timer_expired;
 656        tid_tx->addba_resp_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 657        init_timer(&tid_tx->addba_resp_timer);
 658
 659        /* tx timer */
 660        tid_tx->session_timer.function = sta_tx_agg_session_timer_expired;
 661        tid_tx->session_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 662        init_timer_deferrable(&tid_tx->session_timer);
 663
 664        /* assign a dialog token */
 665        sta->ampdu_mlme.dialog_token_allocator++;
 666        tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;
 667
 668        /*
 669         * Finally, assign it to the start array; the work item will
 670         * collect it and move it to the normal array.
 671         */
 672        sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;
 673
 674        ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 675
 676        /* this flow continues off the work */
 677 err_unlock_sta:
 678        spin_unlock_bh(&sta->lock);
 679        return ret;
 680}
 681EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
 682
 683static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 684                                         struct sta_info *sta, u16 tid)
 685{
 686        struct tid_ampdu_tx *tid_tx;
 687
 688        lockdep_assert_held(&sta->ampdu_mlme.mtx);
 689
 690        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 691
 692        ht_dbg(sta->sdata, "Aggregation is on for %pM tid %d\n",
 693               sta->sta.addr, tid);
 694
 695        drv_ampdu_action(local, sta->sdata,
 696                         IEEE80211_AMPDU_TX_OPERATIONAL,
 697                         &sta->sta, tid, NULL, tid_tx->buf_size,
 698                         tid_tx->amsdu);
 699
 700        /*
 701         * synchronize with TX path, while splicing the TX path
 702         * should block so it won't put more packets onto pending.
 703         */
 704        spin_lock_bh(&sta->lock);
 705
 706        ieee80211_agg_splice_packets(sta->sdata, tid_tx, tid);
 707        /*
 708         * Now mark as operational. This will be visible
 709         * in the TX path, and lets it go lock-free in
 710         * the common case.
 711         */
 712        set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
 713        ieee80211_agg_splice_finish(sta->sdata, tid);
 714
 715        spin_unlock_bh(&sta->lock);
 716
 717        ieee80211_agg_start_txq(sta, tid, true);
 718}
 719
 720void ieee80211_start_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u16 tid)
 721{
 722        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 723        struct ieee80211_local *local = sdata->local;
 724        struct sta_info *sta;
 725        struct tid_ampdu_tx *tid_tx;
 726
 727        trace_api_start_tx_ba_cb(sdata, ra, tid);
 728
 729        if (tid >= IEEE80211_NUM_TIDS) {
 730                ht_dbg(sdata, "Bad TID value: tid = %d (>= %d)\n",
 731                       tid, IEEE80211_NUM_TIDS);
 732                return;
 733        }
 734
 735        mutex_lock(&local->sta_mtx);
 736        sta = sta_info_get_bss(sdata, ra);
 737        if (!sta) {
 738                mutex_unlock(&local->sta_mtx);
 739                ht_dbg(sdata, "Could not find station: %pM\n", ra);
 740                return;
 741        }
 742
 743        mutex_lock(&sta->ampdu_mlme.mtx);
 744        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 745
 746        if (WARN_ON(!tid_tx)) {
 747                ht_dbg(sdata, "addBA was not requested!\n");
 748                goto unlock;
 749        }
 750
 751        if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
 752                goto unlock;
 753
 754        if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
 755                ieee80211_agg_tx_operational(local, sta, tid);
 756
 757 unlock:
 758        mutex_unlock(&sta->ampdu_mlme.mtx);
 759        mutex_unlock(&local->sta_mtx);
 760}
 761
 762void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 763                                      const u8 *ra, u16 tid)
 764{
 765        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 766        struct ieee80211_local *local = sdata->local;
 767        struct ieee80211_ra_tid *ra_tid;
 768        struct sk_buff *skb = dev_alloc_skb(0);
 769
 770        if (unlikely(!skb))
 771                return;
 772
 773        ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 774        memcpy(&ra_tid->ra, ra, ETH_ALEN);
 775        ra_tid->tid = tid;
 776
 777        skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_START;
 778        skb_queue_tail(&sdata->skb_queue, skb);
 779        ieee80211_queue_work(&local->hw, &sdata->work);
 780}
 781EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
 782
 783int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 784                                   enum ieee80211_agg_stop_reason reason)
 785{
 786        int ret;
 787
 788        mutex_lock(&sta->ampdu_mlme.mtx);
 789
 790        ret = ___ieee80211_stop_tx_ba_session(sta, tid, reason);
 791
 792        mutex_unlock(&sta->ampdu_mlme.mtx);
 793
 794        return ret;
 795}
 796
 797int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 798{
 799        struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 800        struct ieee80211_sub_if_data *sdata = sta->sdata;
 801        struct ieee80211_local *local = sdata->local;
 802        struct tid_ampdu_tx *tid_tx;
 803        int ret = 0;
 804
 805        trace_api_stop_tx_ba_session(pubsta, tid);
 806
 807        if (!local->ops->ampdu_action)
 808                return -EINVAL;
 809
 810        if (tid >= IEEE80211_NUM_TIDS)
 811                return -EINVAL;
 812
 813        spin_lock_bh(&sta->lock);
 814        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 815
 816        if (!tid_tx) {
 817                ret = -ENOENT;
 818                goto unlock;
 819        }
 820
 821        WARN(sta->reserved_tid == tid,
 822             "Requested to stop BA session on reserved tid=%d", tid);
 823
 824        if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 825                /* already in progress stopping it */
 826                ret = 0;
 827                goto unlock;
 828        }
 829
 830        set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
 831        ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 832
 833 unlock:
 834        spin_unlock_bh(&sta->lock);
 835        return ret;
 836}
 837EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
 838
 839void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
 840{
 841        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 842        struct ieee80211_local *local = sdata->local;
 843        struct sta_info *sta;
 844        struct tid_ampdu_tx *tid_tx;
 845        bool send_delba = false;
 846
 847        trace_api_stop_tx_ba_cb(sdata, ra, tid);
 848
 849        if (tid >= IEEE80211_NUM_TIDS) {
 850                ht_dbg(sdata, "Bad TID value: tid = %d (>= %d)\n",
 851                       tid, IEEE80211_NUM_TIDS);
 852                return;
 853        }
 854
 855        ht_dbg(sdata, "Stopping Tx BA session for %pM tid %d\n", ra, tid);
 856
 857        mutex_lock(&local->sta_mtx);
 858
 859        sta = sta_info_get_bss(sdata, ra);
 860        if (!sta) {
 861                ht_dbg(sdata, "Could not find station: %pM\n", ra);
 862                goto unlock;
 863        }
 864
 865        mutex_lock(&sta->ampdu_mlme.mtx);
 866        spin_lock_bh(&sta->lock);
 867        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 868
 869        if (!tid_tx || !test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 870                ht_dbg(sdata,
 871                       "unexpected callback to A-MPDU stop for %pM tid %d\n",
 872                       sta->sta.addr, tid);
 873                goto unlock_sta;
 874        }
 875
 876        if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
 877                send_delba = true;
 878
 879        ieee80211_remove_tid_tx(sta, tid);
 880
 881 unlock_sta:
 882        spin_unlock_bh(&sta->lock);
 883
 884        if (send_delba)
 885                ieee80211_send_delba(sdata, ra, tid,
 886                        WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
 887
 888        mutex_unlock(&sta->ampdu_mlme.mtx);
 889 unlock:
 890        mutex_unlock(&local->sta_mtx);
 891}
 892
 893void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
 894                                     const u8 *ra, u16 tid)
 895{
 896        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 897        struct ieee80211_local *local = sdata->local;
 898        struct ieee80211_ra_tid *ra_tid;
 899        struct sk_buff *skb = dev_alloc_skb(0);
 900
 901        if (unlikely(!skb))
 902                return;
 903
 904        ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
 905        memcpy(&ra_tid->ra, ra, ETH_ALEN);
 906        ra_tid->tid = tid;
 907
 908        skb->pkt_type = IEEE80211_SDATA_QUEUE_AGG_STOP;
 909        skb_queue_tail(&sdata->skb_queue, skb);
 910        ieee80211_queue_work(&local->hw, &sdata->work);
 911}
 912EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
 913
 914
 915void ieee80211_process_addba_resp(struct ieee80211_local *local,
 916                                  struct sta_info *sta,
 917                                  struct ieee80211_mgmt *mgmt,
 918                                  size_t len)
 919{
 920        struct tid_ampdu_tx *tid_tx;
 921        u16 capab, tid;
 922        u8 buf_size;
 923        bool amsdu;
 924
 925        capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 926        amsdu = capab & IEEE80211_ADDBA_PARAM_AMSDU_MASK;
 927        tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 928        buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 929        buf_size = min(buf_size, local->hw.max_tx_aggregation_subframes);
 930
 931        mutex_lock(&sta->ampdu_mlme.mtx);
 932
 933        tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
 934        if (!tid_tx)
 935                goto out;
 936
 937        if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
 938                ht_dbg(sta->sdata, "wrong addBA response token, %pM tid %d\n",
 939                       sta->sta.addr, tid);
 940                goto out;
 941        }
 942
 943        del_timer_sync(&tid_tx->addba_resp_timer);
 944
 945        ht_dbg(sta->sdata, "switched off addBA timer for %pM tid %d\n",
 946               sta->sta.addr, tid);
 947
 948        /*
 949         * addba_resp_timer may have fired before we got here, and
 950         * caused WANT_STOP to be set. If the stop then was already
 951         * processed further, STOPPING might be set.
 952         */
 953        if (test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state) ||
 954            test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 955                ht_dbg(sta->sdata,
 956                       "got addBA resp for %pM tid %d but we already gave up\n",
 957                       sta->sta.addr, tid);
 958                goto out;
 959        }
 960
 961        /*
 962         * IEEE 802.11-2007 7.3.1.14:
 963         * In an ADDBA Response frame, when the Status Code field
 964         * is set to 0, the Buffer Size subfield is set to a value
 965         * of at least 1.
 966         */
 967        if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 968                        == WLAN_STATUS_SUCCESS && buf_size) {
 969                if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
 970                                     &tid_tx->state)) {
 971                        /* ignore duplicate response */
 972                        goto out;
 973                }
 974
 975                tid_tx->buf_size = buf_size;
 976                tid_tx->amsdu = amsdu;
 977
 978                if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
 979                        ieee80211_agg_tx_operational(local, sta, tid);
 980
 981                sta->ampdu_mlme.addba_req_num[tid] = 0;
 982
 983                if (tid_tx->timeout) {
 984                        mod_timer(&tid_tx->session_timer,
 985                                  TU_TO_EXP_TIME(tid_tx->timeout));
 986                        tid_tx->last_tx = jiffies;
 987                }
 988
 989        } else {
 990                ___ieee80211_stop_tx_ba_session(sta, tid, AGG_STOP_DECLINED);
 991        }
 992
 993 out:
 994        mutex_unlock(&sta->ampdu_mlme.mtx);
 995}
 996