mac80211: add block ack request capability

This patch adds block ack request capability

Signed-off-by: Ester Kummer <ester.kummer@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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
  *

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),
 };
 
 

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);

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);

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)
 {