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