mac80211: A-MPDU Tx adding basic functionality

This patch adds the following abilities to mac80211:
 - start A-MPDU Tx session
 - stop A-MPDU Tx session
 - call backs to start/stop A-MPDU Tx session
 - sending addBA request
 - processing addBA response

Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 530 insertions, 2 deletions

diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index 28bcdf9fc3df..c323c9af9b8f 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -414,6 +414,329 @@ static int ieee80211_stop(struct net_device *dev)
         return 0;
 }
 
+int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
+{
+        struct ieee80211_local *local = hw_to_local(hw);
+        struct sta_info *sta;
+        struct ieee80211_sub_if_data *sdata;
+        u16 start_seq_num = 0;
+        u8 *state;
+        int ret;
+        DECLARE_MAC_BUF(mac);
+
+        if (tid >= STA_TID_NUM)
+                return -EINVAL;
+
+#ifdef CONFIG_MAC80211_HT_DEBUG
+        printk(KERN_DEBUG "Open BA session requested for %s tid %u\n",
+                                print_mac(mac, ra), tid);
+#endif /* CONFIG_MAC80211_HT_DEBUG */
+
+        sta = sta_info_get(local, ra);
+        if (!sta) {
+                printk(KERN_DEBUG "Could not find the station\n");
+                return -ENOENT;
+        }
+
+        spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+
+        /* we have tried too many times, receiver does not want A-MPDU */
+        if (sta->ampdu_mlme.tid_tx[tid].addba_req_num > HT_AGG_MAX_RETRIES) {
+                ret = -EBUSY;
+                goto start_ba_exit;
+        }
+
+        state = &sta->ampdu_mlme.tid_tx[tid].state;
+        /* check if the TID is not in aggregation flow already */
+        if (*state != HT_AGG_STATE_IDLE) {
+#ifdef CONFIG_MAC80211_HT_DEBUG
+                printk(KERN_DEBUG "BA request denied - session is not "
+                                 "idle on tid %u\n", tid);
+#endif /* CONFIG_MAC80211_HT_DEBUG */
+                ret = -EAGAIN;
+                goto start_ba_exit;
+        }
+
+        /* ensure that TX flow won't interrupt us
+         * until the end of the call to requeue function */
+        spin_lock_bh(&local->mdev->queue_lock);
+
+        /* create a new queue for this aggregation */
+        /* ret = ieee80211_ht_agg_queue_add(local, sta, tid); */
+
+        /* case no queue is available to aggregation
+         * don't switch to aggregation */
+        if (ret) {
+#ifdef CONFIG_MAC80211_HT_DEBUG
+                printk(KERN_DEBUG "BA request denied - no queue available for"
+                                        " tid %d\n", tid);
+#endif /* CONFIG_MAC80211_HT_DEBUG */
+                spin_unlock_bh(&local->mdev->queue_lock);
+                goto start_ba_exit;
+        }
+        sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
+
+        /* Ok, the Addba frame hasn't been sent yet, but if the driver calls the
+         * call back right away, it must see that the flow has begun */
+        *state |= HT_ADDBA_REQUESTED_MSK;
+
+        if (local->ops->ampdu_action)
+                ret = local->ops->ampdu_action(hw, IEEE80211_AMPDU_TX_START,
+                                                ra, tid, &start_seq_num);
+
+        if (ret) {
+                /* No need to requeue the packets in the agg queue, since we
+                 * held the tx lock: no packet could be enqueued to the newly
+                 * allocated queue */
+                /* ieee80211_ht_agg_queue_remove(local, sta, tid, 0); */
+#ifdef CONFIG_MAC80211_HT_DEBUG
+                printk(KERN_DEBUG "BA request denied - HW or queue unavailable"
+                                " for tid %d\n", tid);
+#endif /* CONFIG_MAC80211_HT_DEBUG */
+                spin_unlock_bh(&local->mdev->queue_lock);
+                *state = HT_AGG_STATE_IDLE;
+                goto start_ba_exit;
+        }
+
+        /* Will put all the packets in the new SW queue */
+        /* ieee80211_requeue(local, ieee802_1d_to_ac[tid]); */
+        spin_unlock_bh(&local->mdev->queue_lock);
+
+        /* We have most probably almost emptied the legacy queue */
+        /* ieee80211_wake_queue(local_to_hw(local), ieee802_1d_to_ac[tid]); */
+
+        /* send an addBA request */
+        sta->ampdu_mlme.dialog_token_allocator++;
+        sta->ampdu_mlme.tid_tx[tid].dialog_token =
+                        sta->ampdu_mlme.dialog_token_allocator;
+        sta->ampdu_mlme.tid_tx[tid].ssn = start_seq_num;
+
+        ieee80211_send_addba_request(sta->dev, ra, tid,
+                         sta->ampdu_mlme.tid_tx[tid].dialog_token,
+                         sta->ampdu_mlme.tid_tx[tid].ssn,
+                         0x40, 5000);
+
+        /* activate the timer for the recipient's addBA response */
+        sta->ampdu_mlme.tid_tx[tid].addba_resp_timer.expires =
+                                jiffies + ADDBA_RESP_INTERVAL;
+        add_timer(&sta->ampdu_mlme.tid_tx[tid].addba_resp_timer);
+        printk(KERN_DEBUG "activated addBA response timer on tid %d\n", tid);
+
+start_ba_exit:
+        spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+        sta_info_put(sta);
+        return ret;
+}
+EXPORT_SYMBOL(ieee80211_start_tx_ba_session);
+
+int ieee80211_stop_tx_ba_session(struct ieee80211_hw *hw,
+                                 u8 *ra, u16 tid,
+                                 enum ieee80211_back_parties initiator)
+{
+        struct ieee80211_local *local = hw_to_local(hw);
+        struct sta_info *sta;
+        u8 *state;
+        int ret = 0;
+        DECLARE_MAC_BUF(mac);
+
+        if (tid >= STA_TID_NUM)
+                return -EINVAL;
+
+#ifdef CONFIG_MAC80211_HT_DEBUG
+        printk(KERN_DEBUG "Stop a BA session requested for %s tid %u\n",
+                                print_mac(mac, ra), tid);
+#endif /* CONFIG_MAC80211_HT_DEBUG */
+
+        sta = sta_info_get(local, ra);
+        if (!sta)
+                return -ENOENT;
+
+        /* check if the TID is in aggregation */
+        state = &sta->ampdu_mlme.tid_tx[tid].state;
+        spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+
+        if (*state != HT_AGG_STATE_OPERATIONAL) {
+#ifdef CONFIG_MAC80211_HT_DEBUG
+                printk(KERN_DEBUG "Try to stop Tx aggregation on"
+                                " non active TID\n");
+#endif /* CONFIG_MAC80211_HT_DEBUG */
+                ret = -ENOENT;
+                goto stop_BA_exit;
+        }
+
+        ieee80211_stop_queue(hw, sta->tid_to_tx_q[tid]);
+
+        *state = HT_AGG_STATE_REQ_STOP_BA_MSK |
+                (initiator << HT_AGG_STATE_INITIATOR_SHIFT);
+
+        if (local->ops->ampdu_action)
+                ret = local->ops->ampdu_action(hw, IEEE80211_AMPDU_TX_STOP,
+                                                ra, tid, NULL);
+
+        /* case HW denied going back to legacy */
+        if (ret) {
+                WARN_ON(ret != -EBUSY);
+                *state = HT_AGG_STATE_OPERATIONAL;
+                ieee80211_wake_queue(hw, sta->tid_to_tx_q[tid]);
+                goto stop_BA_exit;
+        }
+
+stop_BA_exit:
+        spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+        sta_info_put(sta);
+        return ret;
+}
+EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);
+
+void ieee80211_start_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u16 tid)
+{
+        struct ieee80211_local *local = hw_to_local(hw);
+        struct sta_info *sta;
+        u8 *state;
+        DECLARE_MAC_BUF(mac);
+
+        if (tid >= STA_TID_NUM) {
+                printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
+                                tid, STA_TID_NUM);
+                return;
+        }
+
+        sta = sta_info_get(local, ra);
+        if (!sta) {
+                printk(KERN_DEBUG "Could not find station: %s\n",
+                                print_mac(mac, ra));
+                return;
+        }
+
+        state = &sta->ampdu_mlme.tid_tx[tid].state;
+        spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+
+        if (!(*state & HT_ADDBA_REQUESTED_MSK)) {
+                printk(KERN_DEBUG "addBA was not requested yet, state is %d\n",
+                                *state);
+                spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+                sta_info_put(sta);
+                return;
+        }
+
+        WARN_ON_ONCE(*state & HT_ADDBA_DRV_READY_MSK);
+
+        *state |= HT_ADDBA_DRV_READY_MSK;
+
+        if (*state == HT_AGG_STATE_OPERATIONAL) {
+                printk(KERN_DEBUG "Aggregation is on for tid %d \n", tid);
+                ieee80211_wake_queue(hw, sta->tid_to_tx_q[tid]);
+        }
+        spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+        sta_info_put(sta);
+}
+EXPORT_SYMBOL(ieee80211_start_tx_ba_cb);
+
+void ieee80211_stop_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u8 tid)
+{
+        struct ieee80211_local *local = hw_to_local(hw);
+        struct sta_info *sta;
+        u8 *state;
+        int agg_queue;
+        DECLARE_MAC_BUF(mac);
+
+        if (tid >= STA_TID_NUM) {
+                printk(KERN_DEBUG "Bad TID value: tid = %d (>= %d)\n",
+                                tid, STA_TID_NUM);
+                return;
+        }
+
+        printk(KERN_DEBUG "Stop a BA session requested on DA %s tid %d\n",
+                                print_mac(mac, ra), tid);
+
+        sta = sta_info_get(local, ra);
+        if (!sta) {
+                printk(KERN_DEBUG "Could not find station: %s\n",
+                                print_mac(mac, ra));
+                return;
+        }
+        state = &sta->ampdu_mlme.tid_tx[tid].state;
+
+        spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+        if ((*state & HT_AGG_STATE_REQ_STOP_BA_MSK) == 0) {
+                printk(KERN_DEBUG "unexpected callback to A-MPDU stop\n");
+                sta_info_put(sta);
+                spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+                return;
+        }
+
+        if (*state & HT_AGG_STATE_INITIATOR_MSK)
+                ieee80211_send_delba(sta->dev, ra, tid,
+                        WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
+
+        agg_queue = sta->tid_to_tx_q[tid];
+
+        /* avoid ordering issues: we are the only one that can modify
+         * the content of the qdiscs */
+        spin_lock_bh(&local->mdev->queue_lock);
+        /* remove the queue for this aggregation */
+        /* ieee80211_ht_agg_queue_remove(local, sta, tid, 1); */
+        spin_unlock_bh(&local->mdev->queue_lock);
+
+        /* we just requeued the all the frames that were in the removed
+         * queue, and since we might miss a softirq we do netif_schedule.
+         * ieee80211_wake_queue is not used here as this queue is not
+         * necessarily stopped */
+        netif_schedule(local->mdev);
+        *state = HT_AGG_STATE_IDLE;
+        sta->ampdu_mlme.tid_tx[tid].addba_req_num = 0;
+        spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+
+        sta_info_put(sta);
+}
+EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb);
+
+void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
+                                      const u8 *ra, u16 tid)
+{
+        struct ieee80211_local *local = hw_to_local(hw);
+        struct ieee80211_ra_tid *ra_tid;
+        struct sk_buff *skb = dev_alloc_skb(0);
+
+        if (unlikely(!skb)) {
+                if (net_ratelimit())
+                        printk(KERN_WARNING "%s: Not enough memory, "
+                               "dropping start BA session", skb->dev->name);
+                return;
+        }
+        ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
+        memcpy(&ra_tid->ra, ra, ETH_ALEN);
+        ra_tid->tid = tid;
+
+        skb->pkt_type = IEEE80211_ADDBA_MSG;
+        skb_queue_tail(&local->skb_queue, skb);
+        tasklet_schedule(&local->tasklet);
+}
+EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);
+
+void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_hw *hw,
+                                     const u8 *ra, u16 tid)
+{
+        struct ieee80211_local *local = hw_to_local(hw);
+        struct ieee80211_ra_tid *ra_tid;
+        struct sk_buff *skb = dev_alloc_skb(0);
+
+        if (unlikely(!skb)) {
+                if (net_ratelimit())
+                        printk(KERN_WARNING "%s: Not enough memory, "
+                               "dropping stop BA session", skb->dev->name);
+                return;
+        }
+        ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
+        memcpy(&ra_tid->ra, ra, ETH_ALEN);
+        ra_tid->tid = tid;
+
+        skb->pkt_type = IEEE80211_DELBA_MSG;
+        skb_queue_tail(&local->skb_queue, skb);
+        tasklet_schedule(&local->tasklet);
+}
+EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);
+
 static void ieee80211_set_multicast_list(struct net_device *dev)
 {
         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
@@ -713,6 +1036,7 @@ static void ieee80211_tasklet_handler(unsigned long data)
         struct sk_buff *skb;
         struct ieee80211_rx_status rx_status;
         struct ieee80211_tx_status *tx_status;
+        struct ieee80211_ra_tid *ra_tid;
 
         while ((skb = skb_dequeue(&local->skb_queue)) ||
                (skb = skb_dequeue(&local->skb_queue_unreliable))) {
@@ -733,6 +1057,18 @@ static void ieee80211_tasklet_handler(unsigned long data)
                                             skb, tx_status);
                         kfree(tx_status);
                         break;
+                case IEEE80211_DELBA_MSG:
+                        ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
+                        ieee80211_stop_tx_ba_cb(local_to_hw(local),
+                                                ra_tid->ra, ra_tid->tid);
+                        dev_kfree_skb(skb);
+                        break;
+                case IEEE80211_ADDBA_MSG:
+                        ra_tid = (struct ieee80211_ra_tid *) &skb->cb;
+                        ieee80211_start_tx_ba_cb(local_to_hw(local),
+                                                 ra_tid->ra, ra_tid->tid);
+                        dev_kfree_skb(skb);
+                        break ;
                 default: /* should never get here! */
                         printk(KERN_ERR "%s: Unknown message type (%d)\n",
                                wiphy_name(local->hw.wiphy), skb->pkt_type);
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 72ecbf7bf962..8a24c2c6ebc1 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -407,6 +407,8 @@ struct ieee80211_sub_if_data *vif_to_sdata(struct ieee80211_vif *p)
 enum {
         IEEE80211_RX_MSG        = 1,
         IEEE80211_TX_STATUS_MSG = 2,
+        IEEE80211_DELBA_MSG     = 3,
+        IEEE80211_ADDBA_MSG     = 4,
 };
 
 struct ieee80211_local {
@@ -627,6 +629,12 @@ struct ieee80211_local {
 #endif
 };
 
+/* this struct represents 802.11n's RA/TID combination */
+struct ieee80211_ra_tid {
+        u8 ra[ETH_ALEN];
+        u16 tid;
+};
+
 static inline struct ieee80211_local *hw_to_local(
         struct ieee80211_hw *hw)
 {
@@ -782,9 +790,15 @@ int ieee80211_ht_cap_ie_to_ht_info(struct ieee80211_ht_cap *ht_cap_ie,
 int ieee80211_ht_addt_info_ie_to_ht_bss_info(
                         struct ieee80211_ht_addt_info *ht_add_info_ie,
                         struct ieee80211_ht_bss_info *bss_info);
+void ieee80211_send_addba_request(struct net_device *dev, const u8 *da,
+                                  u16 tid, u8 dialog_token, u16 start_seq_num,
+                                  u16 agg_size, u16 timeout);
+void ieee80211_send_delba(struct net_device *dev, const u8 *da, u16 tid,
+                                u16 initiator, u16 reason_code);
 void ieee80211_sta_stop_rx_ba_session(struct net_device *dev, u8 *da,
                                 u16 tid, u16 initiator, u16 reason);
 void sta_rx_agg_session_timer_expired(unsigned long data);
+void sta_addba_resp_timer_expired(unsigned long data);
 /* ieee80211_iface.c */
 int ieee80211_if_add(struct net_device *dev, const char *name,
                      struct net_device **new_dev, int type);
diff --git a/net/mac80211/ieee80211_sta.c b/net/mac80211/ieee80211_sta.c
index d5d5610db1bd..c4d57346eacf 100644
--- a/net/mac80211/ieee80211_sta.c
+++ b/net/mac80211/ieee80211_sta.c
@@ -1045,6 +1045,58 @@ static void ieee80211_send_addba_resp(struct net_device *dev, u8 *da, u16 tid,
         return;
 }
 
+void ieee80211_send_addba_request(struct net_device *dev, const u8 *da,
+                                u16 tid, u8 dialog_token, u16 start_seq_num,
+                                u16 agg_size, u16 timeout)
+{
+        struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
+        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+        struct ieee80211_if_sta *ifsta = &sdata->u.sta;
+        struct sk_buff *skb;
+        struct ieee80211_mgmt *mgmt;
+        u16 capab;
+
+        skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom + 1 +
+                                sizeof(mgmt->u.action.u.addba_req));
+
+
+        if (!skb) {
+                printk(KERN_ERR "%s: failed to allocate buffer "
+                                "for addba request frame\n", dev->name);
+                return;
+        }
+        skb_reserve(skb, local->hw.extra_tx_headroom);
+        mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
+        memset(mgmt, 0, 24);
+        memcpy(mgmt->da, da, ETH_ALEN);
+        memcpy(mgmt->sa, dev->dev_addr, ETH_ALEN);
+        if (sdata->vif.type == IEEE80211_IF_TYPE_AP)
+                memcpy(mgmt->bssid, dev->dev_addr, ETH_ALEN);
+        else
+                memcpy(mgmt->bssid, ifsta->bssid, ETH_ALEN);
+
+        mgmt->frame_control = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
+                                        IEEE80211_STYPE_ACTION);
+
+        skb_put(skb, 1 + sizeof(mgmt->u.action.u.addba_req));
+
+        mgmt->u.action.category = WLAN_CATEGORY_BACK;
+        mgmt->u.action.u.addba_req.action_code = WLAN_ACTION_ADDBA_REQ;
+
+        mgmt->u.action.u.addba_req.dialog_token = dialog_token;
+        capab = (u16)(1 << 1);          /* bit 1 aggregation policy */
+        capab |= (u16)(tid << 2);       /* bit 5:2 TID number */
+        capab |= (u16)(agg_size << 6);  /* bit 15:6 max size of aggergation */
+
+        mgmt->u.action.u.addba_req.capab = cpu_to_le16(capab);
+
+        mgmt->u.action.u.addba_req.timeout = cpu_to_le16(timeout);
+        mgmt->u.action.u.addba_req.start_seq_num =
+                                        cpu_to_le16(start_seq_num << 4);
+
+        ieee80211_sta_tx(dev, skb, 0);
+}
+
 static void ieee80211_sta_process_addba_request(struct net_device *dev,
                                                 struct ieee80211_mgmt *mgmt,
                                                 size_t len)
@@ -1156,8 +1208,80 @@ end_no_lock:
         sta_info_put(sta);
 }
 
-static void ieee80211_send_delba(struct net_device *dev, const u8 *da, u16 tid,
-                                 u16 initiator, u16 reason_code)
+static void ieee80211_sta_process_addba_resp(struct net_device *dev,
+                                             struct ieee80211_mgmt *mgmt,
+                                             size_t len)
+{
+        struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
+        struct ieee80211_hw *hw = &local->hw;
+        struct sta_info *sta;
+        u16 capab;
+        u16 tid;
+        u8 *state;
+
+        sta = sta_info_get(local, mgmt->sa);
+        if (!sta)
+                return;
+
+        capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
+        tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
+
+        state = &sta->ampdu_mlme.tid_tx[tid].state;
+
+        spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+
+        if (mgmt->u.action.u.addba_resp.dialog_token !=
+                sta->ampdu_mlme.tid_tx[tid].dialog_token) {
+                spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+#ifdef CONFIG_MAC80211_HT_DEBUG
+                printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
+#endif /* CONFIG_MAC80211_HT_DEBUG */
+                sta_info_put(sta);
+                return;
+        }
+
+        del_timer_sync(&sta->ampdu_mlme.tid_tx[tid].addba_resp_timer);
+#ifdef CONFIG_MAC80211_HT_DEBUG
+        printk(KERN_DEBUG "switched off addBA timer for tid %d \n", tid);
+#endif /* CONFIG_MAC80211_HT_DEBUG */
+        if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
+                        == WLAN_STATUS_SUCCESS) {
+                if (!(*state & HT_ADDBA_REQUESTED_MSK)) {
+                        spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+                        printk(KERN_DEBUG "state not HT_ADDBA_REQUESTED_MSK:"
+                                "%d\n", *state);
+                        sta_info_put(sta);
+                        return;
+                }
+
+                if (*state & HT_ADDBA_RECEIVED_MSK)
+                        printk(KERN_DEBUG "double addBA response\n");
+
+                *state |= HT_ADDBA_RECEIVED_MSK;
+                sta->ampdu_mlme.tid_tx[tid].addba_req_num = 0;
+
+                if (*state == HT_AGG_STATE_OPERATIONAL) {
+                        printk(KERN_DEBUG "Aggregation on for tid %d \n", tid);
+                        ieee80211_wake_queue(hw, sta->tid_to_tx_q[tid]);
+                }
+
+                spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+                printk(KERN_DEBUG "recipient accepted agg: tid %d \n", tid);
+        } else {
+                printk(KERN_DEBUG "recipient rejected agg: tid %d \n", tid);
+
+                sta->ampdu_mlme.tid_tx[tid].addba_req_num++;
+                /* this will allow the state check in stop_BA_session */
+                *state = HT_AGG_STATE_OPERATIONAL;
+                spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+                ieee80211_stop_tx_ba_session(hw, sta->addr, tid,
+                                             WLAN_BACK_INITIATOR);
+        }
+        sta_info_put(sta);
+}
+
+void ieee80211_send_delba(struct net_device *dev, const u8 *da, u16 tid,
+                          u16 initiator, u16 reason_code)
 {
         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
@@ -1259,6 +1383,7 @@ void ieee80211_sta_stop_rx_ba_session(struct net_device *dev, u8 *ra, u16 tid,
         sta_info_put(sta);
 }
 
+
 static void ieee80211_sta_process_delba(struct net_device *dev,
                         struct ieee80211_mgmt *mgmt, size_t len)
 {
@@ -1290,6 +1415,53 @@ static void ieee80211_sta_process_delba(struct net_device *dev,
 }
 
 /*
+ * After sending add Block Ack request we activated a timer until
+ * add Block Ack response will arrive from the recipient.
+ * If this timer expires sta_addba_resp_timer_expired will be executed.
+ */
+void sta_addba_resp_timer_expired(unsigned long data)
+{
+        /* not an elegant detour, but there is no choice as the timer passes
+         * only one argument, and both sta_info and TID are needed, so init
+         * flow in sta_info_add gives the TID as data, while the timer_to_id
+         * array gives the sta through container_of */
+        u16 tid = *(int *)data;
+        struct sta_info *temp_sta = container_of((void *)data,
+                struct sta_info, timer_to_tid[tid]);
+
+        struct ieee80211_local *local = temp_sta->local;
+        struct ieee80211_hw *hw = &local->hw;
+        struct sta_info *sta;
+        u8 *state;
+
+        sta = sta_info_get(local, temp_sta->addr);
+        if (!sta)
+                return;
+
+        state = &sta->ampdu_mlme.tid_tx[tid].state;
+        /* check if the TID waits for addBA response */
+        spin_lock_bh(&sta->ampdu_mlme.ampdu_tx);
+        if (!(*state & HT_ADDBA_REQUESTED_MSK)) {
+                spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+                *state = HT_AGG_STATE_IDLE;
+                printk(KERN_DEBUG "timer expired on tid %d but we are not "
+                                "expecting addBA response there", tid);
+                goto timer_expired_exit;
+        }
+
+        printk(KERN_DEBUG "addBA response timer expired on tid %d\n", tid);
+
+        /* go through the state check in stop_BA_session */
+        *state = HT_AGG_STATE_OPERATIONAL;
+        spin_unlock_bh(&sta->ampdu_mlme.ampdu_tx);
+        ieee80211_stop_tx_ba_session(hw, temp_sta->addr, tid,
+                                     WLAN_BACK_INITIATOR);
+
+timer_expired_exit:
+        sta_info_put(sta);
+}
+
+/*
  * After receiving Block Ack Request (BAR) we activated a
  * timer after each frame arrives from the originator.
  * if this timer expires ieee80211_sta_stop_rx_ba_session will be executed.
@@ -2236,6 +2408,12 @@ static void ieee80211_rx_mgmt_action(struct net_device *dev,
                                 break;
                         ieee80211_sta_process_addba_request(dev, mgmt, len);
                         break;
+                case WLAN_ACTION_ADDBA_RESP:
+                        if (len < (IEEE80211_MIN_ACTION_SIZE +
+                                   sizeof(mgmt->u.action.u.addba_resp)))
+                                break;
+                        ieee80211_sta_process_addba_resp(dev, mgmt, len);
+                        break;
                 case WLAN_ACTION_DELBA:
                         if (len < (IEEE80211_MIN_ACTION_SIZE +
                                    sizeof(mgmt->u.action.u.delba)))