5 files changed, 56 insertions, 2 deletions

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index cffd6d0094f9..aa603c3d76d1 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -658,6 +658,10 @@ struct ieee80211_bar {
         __le16 start_seq_num;
 } __attribute__((packed));
 
+/* 802.11 BAR control masks */
+#define IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL     0x0000
+#define IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA  0x0004
+
 /**
  * struct ieee80211_ht_cap - HT capabilities
  *
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 3a204acad901..0a5de3ef527a 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -235,6 +235,8 @@ struct ieee80211_bss_conf {
  * @IEEE80211_TX_STAT_ACK: Frame was acknowledged
  * @IEEE80211_TX_STAT_AMPDU: The frame was aggregated, so status
  *      is for the whole aggregation.
+ * @IEEE80211_TX_STAT_AMPDU_NO_BACK: no block ack was returned,
+ *      so consider using block ack request (BAR).
  */
 enum mac80211_tx_control_flags {
         IEEE80211_TX_CTL_REQ_TX_STATUS          = BIT(0),
@@ -260,6 +262,7 @@ enum mac80211_tx_control_flags {
         IEEE80211_TX_STAT_TX_FILTERED           = BIT(20),
         IEEE80211_TX_STAT_ACK                   = BIT(21),
         IEEE80211_TX_STAT_AMPDU                 = BIT(22),
+        IEEE80211_TX_STAT_AMPDU_NO_BACK         = BIT(23),
 };
 
 
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index f90da1bbec49..175cbdd36d7f 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -904,6 +904,7 @@ void ieee80211_send_addba_request(struct net_device *dev, const u8 *da,
                                   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_send_bar(struct net_device *dev, u8 *ra, u16 tid, u16 ssn);
 
 void ieee80211_sta_stop_rx_ba_session(struct net_device *dev, u8 *da,
                                 u16 tid, u16 initiator, u16 reason);
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index f18cfd727872..074f71a62a6d 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -1404,14 +1404,15 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
         struct ieee80211_local *local = hw_to_local(hw);
         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
         u16 frag, type;
+        __le16 fc;
         struct ieee80211_tx_status_rtap_hdr *rthdr;
         struct ieee80211_sub_if_data *sdata;
         struct net_device *prev_dev = NULL;
+        struct sta_info *sta;
 
         rcu_read_lock();
 
         if (info->status.excessive_retries) {
-                struct sta_info *sta;
                 sta = sta_info_get(local, hdr->addr1);
                 if (sta) {
                         if (test_sta_flags(sta, WLAN_STA_PS)) {
@@ -1426,8 +1427,24 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
                 }
         }
 
+        fc = hdr->frame_control;
+
+        if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
+            (ieee80211_is_data_qos(fc))) {
+                u16 tid, ssn;
+                u8 *qc;
+                sta = sta_info_get(local, hdr->addr1);
+                if (sta) {
+                        qc = ieee80211_get_qos_ctl(hdr);
+                        tid = qc[0] & 0xf;
+                        ssn = ((le16_to_cpu(hdr->seq_ctrl) + 0x10)
+                                                & IEEE80211_SCTL_SEQ);
+                        ieee80211_send_bar(sta->sdata->dev, hdr->addr1,
+                                           tid, ssn);
+                }
+        }
+
         if (info->flags & IEEE80211_TX_STAT_TX_FILTERED) {
-                struct sta_info *sta;
                 sta = sta_info_get(local, hdr->addr1);
                 if (sta) {
                         ieee80211_handle_filtered_frame(local, sta, skb);
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 86abdf96390c..e080482b63cd 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1536,6 +1536,35 @@ void ieee80211_send_delba(struct net_device *dev, const u8 *da, u16 tid,
         ieee80211_sta_tx(dev, skb, 0);
 }
 
+void ieee80211_send_bar(struct net_device *dev, u8 *ra, u16 tid, u16 ssn)
+{
+        struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
+        struct sk_buff *skb;
+        struct ieee80211_bar *bar;
+        u16 bar_control = 0;
+
+        skb = dev_alloc_skb(sizeof(*bar) + local->hw.extra_tx_headroom);
+        if (!skb) {
+                printk(KERN_ERR "%s: failed to allocate buffer for "
+                        "bar frame\n", dev->name);
+                return;
+        }
+        skb_reserve(skb, local->hw.extra_tx_headroom);
+        bar = (struct ieee80211_bar *)skb_put(skb, sizeof(*bar));
+        memset(bar, 0, sizeof(*bar));
+        bar->frame_control = IEEE80211_FC(IEEE80211_FTYPE_CTL,
+                                        IEEE80211_STYPE_BACK_REQ);
+        memcpy(bar->ra, ra, ETH_ALEN);
+        memcpy(bar->ta, dev->dev_addr, ETH_ALEN);
+        bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
+        bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
+        bar_control |= (u16)(tid << 12);
+        bar->control = cpu_to_le16(bar_control);
+        bar->start_seq_num = cpu_to_le16(ssn);
+
+        ieee80211_sta_tx(dev, skb, 0);
+}
+
 void ieee80211_sta_stop_rx_ba_session(struct net_device *dev, u8 *ra, u16 tid,
                                         u16 initiator, u16 reason)
 {