linux/net/mac80211/agg-rx.c
<<
>>
Prefs
   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/**
  17 * DOC: RX A-MPDU aggregation
  18 *
  19 * Aggregation on the RX side requires only implementing the
  20 * @ampdu_action callback that is invoked to start/stop any
  21 * block-ack sessions for RX aggregation.
  22 *
  23 * When RX aggregation is started by the peer, the driver is
  24 * notified via @ampdu_action function, with the
  25 * %IEEE80211_AMPDU_RX_START action, and may reject the request
  26 * in which case a negative response is sent to the peer, if it
  27 * accepts it a positive response is sent.
  28 *
  29 * While the session is active, the device/driver are required
  30 * to de-aggregate frames and pass them up one by one to mac80211,
  31 * which will handle the reorder buffer.
  32 *
  33 * When the aggregation session is stopped again by the peer or
  34 * ourselves, the driver's @ampdu_action function will be called
  35 * with the action %IEEE80211_AMPDU_RX_STOP. In this case, the
  36 * call must not fail.
  37 */
  38
  39#include <linux/ieee80211.h>
  40#include <linux/slab.h>
  41#include <linux/export.h>
  42#include <net/mac80211.h>
  43#include "ieee80211_i.h"
  44#include "driver-ops.h"
  45
  46static void ieee80211_free_tid_rx(struct rcu_head *h)
  47{
  48        struct tid_ampdu_rx *tid_rx =
  49                container_of(h, struct tid_ampdu_rx, rcu_head);
  50        int i;
  51
  52        del_timer_sync(&tid_rx->reorder_timer);
  53
  54        for (i = 0; i < tid_rx->buf_size; i++)
  55                dev_kfree_skb(tid_rx->reorder_buf[i]);
  56        kfree(tid_rx->reorder_buf);
  57        kfree(tid_rx->reorder_time);
  58        kfree(tid_rx);
  59}
  60
  61void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
  62                                     u16 initiator, u16 reason, bool tx)
  63{
  64        struct ieee80211_local *local = sta->local;
  65        struct tid_ampdu_rx *tid_rx;
  66
  67        lockdep_assert_held(&sta->ampdu_mlme.mtx);
  68
  69        tid_rx = rcu_dereference_protected(sta->ampdu_mlme.tid_rx[tid],
  70                                        lockdep_is_held(&sta->ampdu_mlme.mtx));
  71
  72        if (!tid_rx)
  73                return;
  74
  75        RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);
  76
  77        ht_dbg(sta->sdata,
  78               "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
  79               sta->sta.addr, tid,
  80               initiator == WLAN_BACK_RECIPIENT ? "recipient" : "inititator",
  81               (int)reason);
  82
  83        if (drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_STOP,
  84                             &sta->sta, tid, NULL, 0))
  85                sdata_info(sta->sdata,
  86                           "HW problem - can not stop rx aggregation for tid %d\n",
  87                           tid);
  88
  89        /* check if this is a self generated aggregation halt */
  90        if (initiator == WLAN_BACK_RECIPIENT && tx)
  91                ieee80211_send_delba(sta->sdata, sta->sta.addr,
  92                                     tid, WLAN_BACK_RECIPIENT, reason);
  93
  94        del_timer_sync(&tid_rx->session_timer);
  95
  96        call_rcu(&tid_rx->rcu_head, ieee80211_free_tid_rx);
  97}
  98
  99void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 100                                    u16 initiator, u16 reason, bool tx)
 101{
 102        mutex_lock(&sta->ampdu_mlme.mtx);
 103        ___ieee80211_stop_rx_ba_session(sta, tid, initiator, reason, tx);
 104        mutex_unlock(&sta->ampdu_mlme.mtx);
 105}
 106
 107void ieee80211_stop_rx_ba_session(struct ieee80211_vif *vif, u16 ba_rx_bitmap,
 108                                  const u8 *addr)
 109{
 110        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 111        struct sta_info *sta;
 112        int i;
 113
 114        rcu_read_lock();
 115        sta = sta_info_get_bss(sdata, addr);
 116        if (!sta) {
 117                rcu_read_unlock();
 118                return;
 119        }
 120
 121        for (i = 0; i < STA_TID_NUM; i++)
 122                if (ba_rx_bitmap & BIT(i))
 123                        set_bit(i, sta->ampdu_mlme.tid_rx_stop_requested);
 124
 125        ieee80211_queue_work(&sta->local->hw, &sta->ampdu_mlme.work);
 126        rcu_read_unlock();
 127}
 128EXPORT_SYMBOL(ieee80211_stop_rx_ba_session);
 129
 130/*
 131 * After accepting the AddBA Request we activated a timer,
 132 * resetting it after each frame that arrives from the originator.
 133 */
 134static void sta_rx_agg_session_timer_expired(unsigned long data)
 135{
 136        /* not an elegant detour, but there is no choice as the timer passes
 137         * only one argument, and various sta_info are needed here, so init
 138         * flow in sta_info_create gives the TID as data, while the timer_to_id
 139         * array gives the sta through container_of */
 140        u8 *ptid = (u8 *)data;
 141        u8 *timer_to_id = ptid - *ptid;
 142        struct sta_info *sta = container_of(timer_to_id, struct sta_info,
 143                                         timer_to_tid[0]);
 144        struct tid_ampdu_rx *tid_rx;
 145        unsigned long timeout;
 146
 147        rcu_read_lock();
 148        tid_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[*ptid]);
 149        if (!tid_rx) {
 150                rcu_read_unlock();
 151                return;
 152        }
 153
 154        timeout = tid_rx->last_rx + TU_TO_JIFFIES(tid_rx->timeout);
 155        if (time_is_after_jiffies(timeout)) {
 156                mod_timer(&tid_rx->session_timer, timeout);
 157                rcu_read_unlock();
 158                return;
 159        }
 160        rcu_read_unlock();
 161
 162        ht_dbg(sta->sdata, "rx session timer expired on tid %d\n", (u16)*ptid);
 163
 164        set_bit(*ptid, sta->ampdu_mlme.tid_rx_timer_expired);
 165        ieee80211_queue_work(&sta->local->hw, &sta->ampdu_mlme.work);
 166}
 167
 168static void sta_rx_agg_reorder_timer_expired(unsigned long data)
 169{
 170        u8 *ptid = (u8 *)data;
 171        u8 *timer_to_id = ptid - *ptid;
 172        struct sta_info *sta = container_of(timer_to_id, struct sta_info,
 173                        timer_to_tid[0]);
 174
 175        rcu_read_lock();
 176        ieee80211_release_reorder_timeout(sta, *ptid);
 177        rcu_read_unlock();
 178}
 179
 180static void ieee80211_send_addba_resp(struct ieee80211_sub_if_data *sdata, u8 *da, u16 tid,
 181                                      u8 dialog_token, u16 status, u16 policy,
 182                                      u16 buf_size, u16 timeout)
 183{
 184        struct ieee80211_local *local = sdata->local;
 185        struct sk_buff *skb;
 186        struct ieee80211_mgmt *mgmt;
 187        u16 capab;
 188
 189        skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
 190        if (!skb)
 191                return;
 192
 193        skb_reserve(skb, local->hw.extra_tx_headroom);
 194        mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
 195        memset(mgmt, 0, 24);
 196        memcpy(mgmt->da, da, ETH_ALEN);
 197        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 198        if (sdata->vif.type == NL80211_IFTYPE_AP ||
 199            sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
 200            sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
 201                memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 202        else if (sdata->vif.type == NL80211_IFTYPE_STATION)
 203                memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
 204        else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
 205                memcpy(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN);
 206
 207        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 208                                          IEEE80211_STYPE_ACTION);
 209
 210        skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_resp));
 211        mgmt->u.action.category = WLAN_CATEGORY_BACK;
 212        mgmt->u.action.u.addba_resp.action_code = WLAN_ACTION_ADDBA_RESP;
 213        mgmt->u.action.u.addba_resp.dialog_token = dialog_token;
 214
 215        capab = (u16)(policy << 1);     /* bit 1 aggregation policy */
 216        capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
 217        capab |= (u16)(buf_size << 6);  /* bit 15:6 max size of aggregation */
 218
 219        mgmt->u.action.u.addba_resp.capab = cpu_to_le16(capab);
 220        mgmt->u.action.u.addba_resp.timeout = cpu_to_le16(timeout);
 221        mgmt->u.action.u.addba_resp.status = cpu_to_le16(status);
 222
 223        ieee80211_tx_skb(sdata, skb);
 224}
 225
 226void ieee80211_process_addba_request(struct ieee80211_local *local,
 227                                     struct sta_info *sta,
 228                                     struct ieee80211_mgmt *mgmt,
 229                                     size_t len)
 230{
 231        struct tid_ampdu_rx *tid_agg_rx;
 232        u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num, status;
 233        u8 dialog_token;
 234        int ret = -EOPNOTSUPP;
 235
 236        /* extract session parameters from addba request frame */
 237        dialog_token = mgmt->u.action.u.addba_req.dialog_token;
 238        timeout = le16_to_cpu(mgmt->u.action.u.addba_req.timeout);
 239        start_seq_num =
 240                le16_to_cpu(mgmt->u.action.u.addba_req.start_seq_num) >> 4;
 241
 242        capab = le16_to_cpu(mgmt->u.action.u.addba_req.capab);
 243        ba_policy = (capab & IEEE80211_ADDBA_PARAM_POLICY_MASK) >> 1;
 244        tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 245        buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 246
 247        status = WLAN_STATUS_REQUEST_DECLINED;
 248
 249        if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
 250                ht_dbg(sta->sdata, "Suspend in progress - Denying ADDBA request\n");
 251                goto end_no_lock;
 252        }
 253
 254        /* sanity check for incoming parameters:
 255         * check if configuration can support the BA policy
 256         * and if buffer size does not exceeds max value */
 257        /* XXX: check own ht delayed BA capability?? */
 258        if (((ba_policy != 1) &&
 259             (!(sta->sta.ht_cap.cap & IEEE80211_HT_CAP_DELAY_BA))) ||
 260            (buf_size > IEEE80211_MAX_AMPDU_BUF)) {
 261                status = WLAN_STATUS_INVALID_QOS_PARAM;
 262                ht_dbg_ratelimited(sta->sdata,
 263                                   "AddBA Req with bad params from %pM on tid %u. policy %d, buffer size %d\n",
 264                                   mgmt->sa, tid, ba_policy, buf_size);
 265                goto end_no_lock;
 266        }
 267        /* determine default buffer size */
 268        if (buf_size == 0)
 269                buf_size = IEEE80211_MAX_AMPDU_BUF;
 270
 271        /* make sure the size doesn't exceed the maximum supported by the hw */
 272        if (buf_size > local->hw.max_rx_aggregation_subframes)
 273                buf_size = local->hw.max_rx_aggregation_subframes;
 274
 275        /* examine state machine */
 276        mutex_lock(&sta->ampdu_mlme.mtx);
 277
 278        if (sta->ampdu_mlme.tid_rx[tid]) {
 279                ht_dbg_ratelimited(sta->sdata,
 280                                   "unexpected AddBA Req from %pM on tid %u\n",
 281                                   mgmt->sa, tid);
 282
 283                /* delete existing Rx BA session on the same tid */
 284                ___ieee80211_stop_rx_ba_session(sta, tid, WLAN_BACK_RECIPIENT,
 285                                                WLAN_STATUS_UNSPECIFIED_QOS,
 286                                                false);
 287        }
 288
 289        /* prepare A-MPDU MLME for Rx aggregation */
 290        tid_agg_rx = kmalloc(sizeof(struct tid_ampdu_rx), GFP_KERNEL);
 291        if (!tid_agg_rx)
 292                goto end;
 293
 294        spin_lock_init(&tid_agg_rx->reorder_lock);
 295
 296        /* rx timer */
 297        tid_agg_rx->session_timer.function = sta_rx_agg_session_timer_expired;
 298        tid_agg_rx->session_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 299        init_timer_deferrable(&tid_agg_rx->session_timer);
 300
 301        /* rx reorder timer */
 302        tid_agg_rx->reorder_timer.function = sta_rx_agg_reorder_timer_expired;
 303        tid_agg_rx->reorder_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 304        init_timer(&tid_agg_rx->reorder_timer);
 305
 306        /* prepare reordering buffer */
 307        tid_agg_rx->reorder_buf =
 308                kcalloc(buf_size, sizeof(struct sk_buff *), GFP_KERNEL);
 309        tid_agg_rx->reorder_time =
 310                kcalloc(buf_size, sizeof(unsigned long), GFP_KERNEL);
 311        if (!tid_agg_rx->reorder_buf || !tid_agg_rx->reorder_time) {
 312                kfree(tid_agg_rx->reorder_buf);
 313                kfree(tid_agg_rx->reorder_time);
 314                kfree(tid_agg_rx);
 315                goto end;
 316        }
 317
 318        ret = drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_START,
 319                               &sta->sta, tid, &start_seq_num, 0);
 320        ht_dbg(sta->sdata, "Rx A-MPDU request on tid %d result %d\n", tid, ret);
 321        if (ret) {
 322                kfree(tid_agg_rx->reorder_buf);
 323                kfree(tid_agg_rx->reorder_time);
 324                kfree(tid_agg_rx);
 325                goto end;
 326        }
 327
 328        /* update data */
 329        tid_agg_rx->dialog_token = dialog_token;
 330        tid_agg_rx->ssn = start_seq_num;
 331        tid_agg_rx->head_seq_num = start_seq_num;
 332        tid_agg_rx->buf_size = buf_size;
 333        tid_agg_rx->timeout = timeout;
 334        tid_agg_rx->stored_mpdu_num = 0;
 335        status = WLAN_STATUS_SUCCESS;
 336
 337        /* activate it for RX */
 338        rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], tid_agg_rx);
 339
 340        if (timeout) {
 341                mod_timer(&tid_agg_rx->session_timer, TU_TO_EXP_TIME(timeout));
 342                tid_agg_rx->last_rx = jiffies;
 343        }
 344
 345end:
 346        mutex_unlock(&sta->ampdu_mlme.mtx);
 347
 348end_no_lock:
 349        ieee80211_send_addba_resp(sta->sdata, sta->sta.addr, tid,
 350                                  dialog_token, status, 1, buf_size, timeout);
 351}
 352
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.