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)
  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 = sta->ampdu_mlme.tid_rx[tid];
  67
  68         if (!tid_rx)
  69                 return;
  70
  71         rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], NULL);
  72
  73 #ifdef CONFIG_MAC80211_HT_DEBUG
  74         printk(KERN_DEBUG "Rx BA session stop requested for %pM tid %u\n",
  75                sta->sta.addr, tid);
  76 #endif /* CONFIG_MAC80211_HT_DEBUG */
  77
  78         if (drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_STOP,
  79                              &sta->sta, tid, NULL))
  80                 printk(KERN_DEBUG "HW problem - can not stop rx "
  81                                 "aggregation for tid %d\n", tid);
  82
  83         /* check if this is a self generated aggregation halt */
  84         if (initiator == WLAN_BACK_RECIPIENT)
  85                 ieee80211_send_delba(sta->sdata, sta->sta.addr,
  86                                      tid, 0, reason);
  87
  88         del_timer_sync(&tid_rx->session_timer);
  89
  90         call_rcu(&tid_rx->rcu_head, ieee80211_free_tid_rx);
  91 }
  92
  93 void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
  94                                     u16 initiator, u16 reason)
  95 {
  96         mutex_lock(&sta->ampdu_mlme.mtx);
  97         ___ieee80211_stop_rx_ba_session(sta, tid, initiator, reason);
  98         mutex_unlock(&sta->ampdu_mlme.mtx);
  99 }
 100
 101 /*
 102  * After accepting the AddBA Request we activated a timer,
 103  * resetting it after each frame that arrives from the originator.
 104  */
 105 static void sta_rx_agg_session_timer_expired(unsigned long data)
 106 {
 107         /* not an elegant detour, but there is no choice as the timer passes
 108          * only one argument, and various sta_info are needed here, so init
 109          * flow in sta_info_create gives the TID as data, while the timer_to_id
 110          * array gives the sta through container_of */
 111         u8 *ptid = (u8 *)data;
 112         u8 *timer_to_id = ptid - *ptid;
 113         struct sta_info *sta = container_of(timer_to_id, struct sta_info,
 114                                          timer_to_tid[0]);
 115
 116 #ifdef CONFIG_MAC80211_HT_DEBUG
 117         printk(KERN_DEBUG "rx session timer expired on tid %d\n", (u16)*ptid);
 118 #endif
 119         set_bit(*ptid, sta->ampdu_mlme.tid_rx_timer_expired);
 120         ieee80211_queue_work(&sta->local->hw, &sta->ampdu_mlme.work);
 121 }
 122
 123 static void ieee80211_send_addba_resp(struct ieee80211_sub_if_data *sdata, u8 *da, u16 tid,
 124                                       u8 dialog_token, u16 status, u16 policy,
 125                                       u16 buf_size, u16 timeout)
 126 {
 127         struct ieee80211_local *local = sdata->local;
 128         struct sk_buff *skb;
 129         struct ieee80211_mgmt *mgmt;
 130         u16 capab;
 131
 132         skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
 133
 134         if (!skb) {
 135                 printk(KERN_DEBUG "%s: failed to allocate buffer "
 136                        "for addba resp frame\n", sdata->name);
 137                 return;
 138         }
 139
 140         skb_reserve(skb, local->hw.extra_tx_headroom);
 141         mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
 142         memset(mgmt, 0, 24);
 143         memcpy(mgmt->da, da, ETH_ALEN);
 144         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 145         if (sdata->vif.type == NL80211_IFTYPE_AP ||
 146             sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
 147                 memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 148         else if (sdata->vif.type == NL80211_IFTYPE_STATION)
 149                 memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
 150
 151         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 152                                           IEEE80211_STYPE_ACTION);
 153
 154         skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_resp));
 155         mgmt->u.action.category = WLAN_CATEGORY_BACK;
 156         mgmt->u.action.u.addba_resp.action_code = WLAN_ACTION_ADDBA_RESP;
 157         mgmt->u.action.u.addba_resp.dialog_token = dialog_token;
 158
 159         capab = (u16)(policy << 1);     /* bit 1 aggregation policy */
 160         capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
 161         capab |= (u16)(buf_size << 6);  /* bit 15:6 max size of aggregation */
 162
 163         mgmt->u.action.u.addba_resp.capab = cpu_to_le16(capab);
 164         mgmt->u.action.u.addba_resp.timeout = cpu_to_le16(timeout);
 165         mgmt->u.action.u.addba_resp.status = cpu_to_le16(status);
 166
 167         ieee80211_tx_skb(sdata, skb);
 168 }
 169
 170 void ieee80211_process_addba_request(struct ieee80211_local *local,
 171                                      struct sta_info *sta,
 172                                      struct ieee80211_mgmt *mgmt,
 173                                      size_t len)
 174 {
 175         struct ieee80211_hw *hw = &local->hw;
 176         struct ieee80211_conf *conf = &hw->conf;
 177         struct tid_ampdu_rx *tid_agg_rx;
 178         u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num, status;
 179         u8 dialog_token;
 180         int ret = -EOPNOTSUPP;
 181
 182         /* extract session parameters from addba request frame */
 183         dialog_token = mgmt->u.action.u.addba_req.dialog_token;
 184         timeout = le16_to_cpu(mgmt->u.action.u.addba_req.timeout);
 185         start_seq_num =
 186                 le16_to_cpu(mgmt->u.action.u.addba_req.start_seq_num) >> 4;
 187
 188         capab = le16_to_cpu(mgmt->u.action.u.addba_req.capab);
 189         ba_policy = (capab & IEEE80211_ADDBA_PARAM_POLICY_MASK) >> 1;
 190         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
 191         buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 192
 193         status = WLAN_STATUS_REQUEST_DECLINED;
 194
 195         if (test_sta_flags(sta, WLAN_STA_BLOCK_BA)) {
 196 #ifdef CONFIG_MAC80211_HT_DEBUG
 197                 printk(KERN_DEBUG "Suspend in progress. "
 198                        "Denying ADDBA request\n");
 199 #endif
 200                 goto end_no_lock;
 201         }
 202
 203         /* sanity check for incoming parameters:
 204          * check if configuration can support the BA policy
 205          * and if buffer size does not exceeds max value */
 206         /* XXX: check own ht delayed BA capability?? */
 207         if (((ba_policy != 1) &&
 208              (!(sta->sta.ht_cap.cap & IEEE80211_HT_CAP_DELAY_BA))) ||
 209             (buf_size > IEEE80211_MAX_AMPDU_BUF)) {
 210                 status = WLAN_STATUS_INVALID_QOS_PARAM;
 211 #ifdef CONFIG_MAC80211_HT_DEBUG
 212                 if (net_ratelimit())
 213                         printk(KERN_DEBUG "AddBA Req with bad params from "
 214                                 "%pM on tid %u. policy %d, buffer size %d\n",
 215                                 mgmt->sa, tid, ba_policy,
 216                                 buf_size);
 217 #endif /* CONFIG_MAC80211_HT_DEBUG */
 218                 goto end_no_lock;
 219         }
 220         /* determine default buffer size */
 221         if (buf_size == 0) {
 222                 struct ieee80211_supported_band *sband;
 223
 224                 sband = local->hw.wiphy->bands[conf->channel->band];
 225                 buf_size = IEEE80211_MIN_AMPDU_BUF;
 226                 buf_size = buf_size << sband->ht_cap.ampdu_factor;
 227         }
 228
 229
 230         /* examine state machine */
 231         mutex_lock(&sta->ampdu_mlme.mtx);
 232
 233         if (sta->ampdu_mlme.tid_rx[tid]) {
 234 #ifdef CONFIG_MAC80211_HT_DEBUG
 235                 if (net_ratelimit())
 236                         printk(KERN_DEBUG "unexpected AddBA Req from "
 237                                 "%pM on tid %u\n",
 238                                 mgmt->sa, tid);
 239 #endif /* CONFIG_MAC80211_HT_DEBUG */
 240                 goto end;
 241         }
 242
 243         /* prepare A-MPDU MLME for Rx aggregation */
 244         tid_agg_rx = kmalloc(sizeof(struct tid_ampdu_rx), GFP_ATOMIC);
 245         if (!tid_agg_rx) {
 246 #ifdef CONFIG_MAC80211_HT_DEBUG
 247                 if (net_ratelimit())
 248                         printk(KERN_ERR "allocate rx mlme to tid %d failed\n",
 249                                         tid);
 250 #endif
 251                 goto end;
 252         }
 253
 254         /* rx timer */
 255         tid_agg_rx->session_timer.function = sta_rx_agg_session_timer_expired;
 256         tid_agg_rx->session_timer.data = (unsigned long)&sta->timer_to_tid[tid];
 257         init_timer(&tid_agg_rx->session_timer);
 258
 259         /* prepare reordering buffer */
 260         tid_agg_rx->reorder_buf =
 261                 kcalloc(buf_size, sizeof(struct sk_buff *), GFP_ATOMIC);
 262         tid_agg_rx->reorder_time =
 263                 kcalloc(buf_size, sizeof(unsigned long), GFP_ATOMIC);
 264         if (!tid_agg_rx->reorder_buf || !tid_agg_rx->reorder_time) {
 265 #ifdef CONFIG_MAC80211_HT_DEBUG
 266                 if (net_ratelimit())
 267                         printk(KERN_ERR "can not allocate reordering buffer "
 268                                "to tid %d\n", tid);
 269 #endif
 270                 kfree(tid_agg_rx->reorder_buf);
 271                 kfree(tid_agg_rx->reorder_time);
 272                 kfree(tid_agg_rx);
 273                 goto end;
 274         }
 275
 276         ret = drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_START,
 277                                &sta->sta, tid, &start_seq_num);
 278 #ifdef CONFIG_MAC80211_HT_DEBUG
 279         printk(KERN_DEBUG "Rx A-MPDU request on tid %d result %d\n", tid, ret);
 280 #endif /* CONFIG_MAC80211_HT_DEBUG */
 281
 282         if (ret) {
 283                 kfree(tid_agg_rx->reorder_buf);
 284                 kfree(tid_agg_rx->reorder_time);
 285                 kfree(tid_agg_rx);
 286                 goto end;
 287         }
 288
 289         /* update data */
 290         tid_agg_rx->dialog_token = dialog_token;
 291         tid_agg_rx->ssn = start_seq_num;
 292         tid_agg_rx->head_seq_num = start_seq_num;
 293         tid_agg_rx->buf_size = buf_size;
 294         tid_agg_rx->timeout = timeout;
 295         tid_agg_rx->stored_mpdu_num = 0;
 296         status = WLAN_STATUS_SUCCESS;
 297
 298         /* activate it for RX */
 299         rcu_assign_pointer(sta->ampdu_mlme.tid_rx[tid], tid_agg_rx);
 300
 301         if (timeout)
 302                 mod_timer(&tid_agg_rx->session_timer, TU_TO_EXP_TIME(timeout));
 303
 304 end:
 305         mutex_unlock(&sta->ampdu_mlme.mtx);
 306
 307 end_no_lock:
 308         ieee80211_send_addba_resp(sta->sdata, sta->sta.addr, tid,
 309                                   dialog_token, status, 1, buf_size, timeout);
 310 }