net/mac80211/agg-rx.c

   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 <net/mac80211.h>
  42 #include "ieee80211_i.h"
  43 #include "driver-ops.h"
  44
  45 static void ieee80211_free_tid_rx(struct rcu_head *h)
  46 {
  47         struct tid_ampdu_rx *tid_rx =
  48                 container_of(h, struct tid_ampdu_rx, rcu_head);
  49         int i;
  50
  51         for (i = 0; i < tid_rx->buf_size; i++)
  52                 dev_kfree_skb(tid_rx->reorder_buf[i]);
  53         kfree(tid_rx->reorder_buf);
  54         kfree(tid_rx->reorder_time);
  55         kfree(tid_rx);
  56 }
  57
  58 void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
  59                                      u16 initiator, u16 reason, bool tx)
  60 {
  61         struct ieee80211_local *local = sta->local;
  62         struct tid_ampdu_rx *tid_rx;
  63
  64         lockdep_assert_held(&sta->ampdu_mlme.mtx);
  65
  66         tid_rx = rcu_dereference_protected(sta->ampdu_mlme.tid_rx[tid],
  67                                         lockdep_is_held(&sta->ampdu_mlme.mtx));
  68
  69         if (!tid_rx)
  70                 return;
  71
  72         rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], NULL);
  73
  74 #ifdef CONFIG_MAC80211_HT_DEBUG
  75         printk(KERN_DEBUG "Rx BA session stop requested for %pM tid %u\n",
  76                sta->sta.addr, tid);
  77 #endif /* CONFIG_MAC80211_HT_DEBUG */
  78
  79         if (drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_STOP,
  80                              &sta->sta, tid, NULL, 0))
  81                 printk(KERN_DEBUG "HW problem - can not stop rx "
  82                                 "aggregation for tid %d\n", tid);
  83
  84         /* check if this is a self generated aggregation halt */
  85         if (initiator == WLAN_BACK_RECIPIENT && tx)
  86                 ieee80211_send_delba(sta->sdata, sta->sta.addr,
  87                                      tid, 0, reason);
  88
  89         del_timer_sync(&tid_rx->session_timer);
  90         del_timer_sync(&tid_rx->reorder_timer);
  91
  92         call_rcu(&tid_rx->rcu_head, ieee80211_free_tid_rx);
  93 }
  94
  95 void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
  96                                     u16 initiator, u16 reason, bool tx)
  97 {
  98         mutex_lock(&sta->ampdu_mlme.mtx);
  99         ___ieee80211_stop_rx_ba_session(sta, tid, initiator, reason, tx);
 100         mutex_unlock(&sta->ampdu_mlme.mtx);
 101 }
 102
 103 /*
 104  * After accepting the AddBA Request we activated a timer,
 105  * resetting it after each frame that arrives from the originator.
 106  */
 107 static void sta_rx_agg_session_timer_expired(unsigned long data)
 108 {
 109         /* not an elegant detour, but there is no choice as the timer passes
 110          * only one argument, and various sta_info are needed here, so init
 111          * flow in sta_info_create gives the TID as data, while the timer_to_id
 112          * array gives the sta through container_of */
 113         u8 *ptid = (u8 *)data;
 114         u8 *timer_to_id = ptid - *ptid;
 115         struct sta_info *sta = container_of(timer_to_id, struct sta_info,
 116                                          timer_to_tid[0]);
 117
 118 #ifdef CONFIG_MAC80211_HT_DEBUG
 119         printk(KERN_DEBUG "rx session timer expired on tid %d\n", (u16)*ptid);
 120 #endif
 121         set_bit(*ptid, sta->ampdu_mlme.tid_rx_timer_expired);
 122         ieee80211_queue_work(&sta->local->hw, &sta->ampdu_mlme.work);
 123 }
 124
 125 static void sta_rx_agg_reorder_timer_expired(unsigned long data)
 126 {
 127         u8 *ptid = (u8 *)data;
 128         u8 *timer_to_id = ptid - *ptid;
 129         struct sta_info *sta = container_of(timer_to_id, struct sta_info,
 130                         timer_to_tid[0]);
 131
 132         rcu_read_lock();
 133         ieee80211_release_reorder_timeout(sta, *ptid);
 134         rcu_read_unlock();
 135 }
 136
 137 static void ieee80211_send_addba_resp(struct ieee80211_sub_if_data *sdata, u8 *da, u16 tid,
 138                                       u8 dialog_token, u16 status, u16 policy,
 139                                       u16 buf_size, u16 timeout)
 140 {
 141         struct ieee80211_local *local = sdata->local;
 142         struct sk_buff *skb;
 143         struct ieee80211_mgmt *mgmt;
 144         u16 capab;
 145
 146         skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
 147
 148         if (!skb) {
 149                 printk(KERN_DEBUG "%s: failed to allocate buffer "
 150                        "for addba resp frame\n", sdata->name);
 151                 return;
 152         }
 153
 154         skb_reserve(skb, local->hw.extra_tx_headroom);
 155         mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
 156         memset(mgmt, 0, 24);
 157         memcpy(mgmt->da, da, ETH_ALEN);
 158         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 159         if (sdata->vif.type == NL80211_IFTYPE_AP ||
 160             sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
 161                 memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 162         else if (sdata->vif.type == NL80211_IFTYPE_STATION)
 163                 memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
 164
 165         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 166                                           IEEE80211_STYPE_ACTION);
 167
 168         skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_resp));
 169         mgmt->u.action.category = WLAN_CATEGORY_BACK;
 170         mgmt->u.action.u.addba_resp.action_code = WLAN_ACTION_ADDBA_RESP;
 171         mgmt->u.action.u.addba_resp.dialog_token = dialog_token;
 172
 173         capab = (u16)(policy << 1);     /* bit 1 aggregation policy */
 174         capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
 175         capab |= (u16)(buf_size << 6);  /* bit 15:6 max size of aggregation */
 176
 177         mgmt->u.action.u.addba_resp.capab = cpu_to_le16(capab);
 178         mgmt->u.action.u.addba_resp.timeout = cpu_to_le16(timeout);
 179         mgmt->u.action.u.addba_resp.status = cpu_to_le16(status);
 180
 181         ieee80211_tx_skb(sdata, skb);
 182 }
 183
 184 void ieee80211_process_addba_request(struct ieee80211_local *local,
 185                                      struct sta_info *sta,
 186                                      struct ieee80211_mgmt *mgmt,
 187                                      size_t len)
 188 {
 189         struct tid_ampdu_rx *tid_agg_rx;
 190         u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num, status;
 191         u8 dialog_token;
 192         int ret = -EOPNOTSUPP;
 193
 194         /* extract session parameters from addba request frame */
 195         dialog_token = mgmt->u.action.u.addba_req.dialog_token;
 196         timeout = le16_to_cpu(mgmt->u.action.u.addba_req.timeout);
 197         start_seq_num =
 198                 le16_to_cpu(mgmt->u.action.u.addba_req.start_seq_num) >> 4;
 199
 200         capab = le16_to_cpu(mgmt->u.action.u.addba_req.capab);
 201         ba_policy = (capab & IEEE80211_ADDBA_PARAM_POLICY_MASK) >> 1;
 202         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 203         buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 204
 205         status = WLAN_STATUS_REQUEST_DECLINED;
 206
 207         if (test_sta_flags(sta, WLAN_STA_BLOCK_BA)) {
 208 #ifdef CONFIG_MAC80211_HT_DEBUG
 209                 printk(KERN_DEBUG "Suspend in progress. "
 210                        "Denying ADDBA request\n");
 211 #endif
 212                 goto end_no_lock;
 213         }
 214
 215         /* sanity check for incoming parameters:
 216          * check if configuration can support the BA policy
 217          * and if buffer size does not exceeds max value */
 218         /* XXX: check own ht delayed BA capability?? */
 219         if (((ba_policy != 1) &&
 220              (!(sta->sta.ht_cap.cap & IEEE80211_HT_CAP_DELAY_BA))) ||
 221             (buf_size > IEEE80211_MAX_AMPDU_BUF)) {
 222                 status = WLAN_STATUS_INVALID_QOS_PARAM;
 223 #ifdef CONFIG_MAC80211_HT_DEBUG
 224                 if (net_ratelimit())
 225                         printk(KERN_DEBUG "AddBA Req with bad params from "
 226                                 "%pM on tid %u. policy %d, buffer size %d\n",
 227                                 mgmt->sa, tid, ba_policy,
 228                                 buf_size);
 229 #endif /* CONFIG_MAC80211_HT_DEBUG */
 230                 goto end_no_lock;
 231         }
 232         /* determine default buffer size */
 233         if (buf_size == 0)
 234                 buf_size = IEEE80211_MAX_AMPDU_BUF;
 235
 236         /* make sure the size doesn't exceed the maximum supported by the hw */
 237         if (buf_size > local->hw.max_rx_aggregation_subframes)
 238                 buf_size = local->hw.max_rx_aggregation_subframes;
 239
 240         /* examine state machine */
 241         mutex_lock(&sta->ampdu_mlme.mtx);
 242
 243         if (sta->ampdu_mlme.tid_rx[tid]) {
 244 #ifdef CONFIG_MAC80211_HT_DEBUG
 245                 if (net_ratelimit())
 246                         printk(KERN_DEBUG "unexpected AddBA Req from "
 247                                 "%pM on tid %u\n",
 248                                 mgmt->sa, tid);
 249 #endif /* CONFIG_MAC80211_HT_DEBUG */
 250                 goto end;
 251         }
 252
 253         /* prepare A-MPDU MLME for Rx aggregation */
 254         tid_agg_rx = kmalloc(sizeof(struct tid_ampdu_rx), GFP_KERNEL);
 255         if (!tid_agg_rx) {
 256 #ifdef CONFIG_MAC80211_HT_DEBUG
 257                 if (net_ratelimit())
 258                         printk(KERN_ERR "allocate rx mlme to tid %d failed\n",
 259                                         tid);
 260 #endif
 261                 goto end;
 262         }
 263
 264         spin_lock_init(&tid_agg_rx->reorder_lock);
 265
 266         /* rx timer */
 267         tid_agg_rx->session_timer.function = sta_rx_agg_session_timer_expired;
 268         tid_agg_rx->session_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 269         init_timer(&tid_agg_rx->session_timer);
 270
 271         /* rx reorder timer */
 272         tid_agg_rx->reorder_timer.function = sta_rx_agg_reorder_timer_expired;
 273         tid_agg_rx->reorder_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 274         init_timer(&tid_agg_rx->reorder_timer);
 275
 276         /* prepare reordering buffer */
 277         tid_agg_rx->reorder_buf =
 278                 kcalloc(buf_size, sizeof(struct sk_buff *), GFP_KERNEL);
 279         tid_agg_rx->reorder_time =
 280                 kcalloc(buf_size, sizeof(unsigned long), GFP_KERNEL);
 281         if (!tid_agg_rx->reorder_buf || !tid_agg_rx->reorder_time) {
 282 #ifdef CONFIG_MAC80211_HT_DEBUG
 283                 if (net_ratelimit())
 284                         printk(KERN_ERR "can not allocate reordering buffer "
 285                                "to tid %d\n", tid);
 286 #endif
 287                 kfree(tid_agg_rx->reorder_buf);
 288                 kfree(tid_agg_rx->reorder_time);
 289                 kfree(tid_agg_rx);
 290                 goto end;
 291         }
 292
 293         ret = drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_START,
 294                                &sta->sta, tid, &start_seq_num, 0);
 295 #ifdef CONFIG_MAC80211_HT_DEBUG
 296         printk(KERN_DEBUG "Rx A-MPDU request on tid %d result %d\n", tid, ret);
 297 #endif /* CONFIG_MAC80211_HT_DEBUG */
 298
 299         if (ret) {
 300                 kfree(tid_agg_rx->reorder_buf);
 301                 kfree(tid_agg_rx->reorder_time);
 302                 kfree(tid_agg_rx);
 303                 goto end;
 304         }
 305
 306         /* update data */
 307         tid_agg_rx->dialog_token = dialog_token;
 308         tid_agg_rx->ssn = start_seq_num;
 309         tid_agg_rx->head_seq_num = start_seq_num;
 310         tid_agg_rx->buf_size = buf_size;
 311         tid_agg_rx->timeout = timeout;
 312         tid_agg_rx->stored_mpdu_num = 0;
 313         status = WLAN_STATUS_SUCCESS;
 314
 315         /* activate it for RX */
 316         rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], tid_agg_rx);
 317
 318         if (timeout)
 319                 mod_timer(&tid_agg_rx->session_timer, TU_TO_EXP_TIME(timeout));
 320
 321 end:
 322         mutex_unlock(&sta->ampdu_mlme.mtx);
 323
 324 end_no_lock:
 325         ieee80211_send_addba_resp(sta->sdata, sta->sta.addr, tid,
 326                                   dialog_token, status, 1, buf_size, timeout);
 327 }