mac80211: A-MPDU Rx adding BAR handling capability

This patch adds the ability to handle Block Ack Request

Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mac80211/ieee80211_i.h

@@ -801,7 +801,8 @@ int ieee80211_subif_start_xmit(struct sk_buff *skb, struct net_device *dev);
 extern void *mac80211_wiphy_privid; /* for wiphy privid */
 extern const unsigned char rfc1042_header[6];
 extern const unsigned char bridge_tunnel_header[6];
-u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len);
+u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
+			enum ieee80211_if_types type);
 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 			     int rate, int erp, int short_preamble);
 void mac80211_ev_michael_mic_failure(struct net_device *dev, int keyidx,

net/mac80211/rx.c

@@ -24,6 +24,10 @@
 #include "tkip.h"
 #include "wme.h"
 
+u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
+				struct tid_ampdu_rx *tid_agg_rx,
+				struct sk_buff *skb, u16 mpdu_seq_num,
+				int bar_req);
 /*
  * monitor mode reception
  *
@@ -64,7 +68,9 @@ static inline int should_drop_frame(struct ieee80211_rx_status *status,
 	if (((hdr->frame_control & cpu_to_le16(IEEE80211_FCTL_FTYPE)) ==
 			cpu_to_le16(IEEE80211_FTYPE_CTL)) &&
 	    ((hdr->frame_control & cpu_to_le16(IEEE80211_FCTL_STYPE)) !=
-			cpu_to_le16(IEEE80211_STYPE_PSPOLL)))
+			cpu_to_le16(IEEE80211_STYPE_PSPOLL)) &&
+	    ((hdr->frame_control & cpu_to_le16(IEEE80211_FCTL_STYPE)) !=
+			cpu_to_le16(IEEE80211_STYPE_BACK_REQ)))
 		return 1;
 	return 0;
 }
@@ -634,7 +640,8 @@ ieee80211_rx_h_sta_process(struct ieee80211_txrx_data *rx)
 	 * BSSID to avoid keeping the current IBSS network alive in cases where
 	 * other STAs are using different BSSID. */
 	if (rx->sdata->type == IEEE80211_IF_TYPE_IBSS) {
-		u8 *bssid = ieee80211_get_bssid(hdr, rx->skb->len);
+		u8 *bssid = ieee80211_get_bssid(hdr, rx->skb->len,
+						IEEE80211_IF_TYPE_IBSS);
 		if (compare_ether_addr(bssid, rx->sdata->u.sta.bssid) == 0)
 			sta->last_rx = jiffies;
 	} else
@@ -1376,6 +1383,49 @@ ieee80211_rx_h_data(struct ieee80211_txrx_data *rx)
 	return TXRX_QUEUED;
 }
 
+static ieee80211_txrx_result
+ieee80211_rx_h_ctrl(struct ieee80211_txrx_data *rx)
+{
+	struct ieee80211_local *local = rx->local;
+	struct ieee80211_hw *hw = &local->hw;
+	struct sk_buff *skb = rx->skb;
+	struct ieee80211_bar *bar = (struct ieee80211_bar *) skb->data;
+	struct tid_ampdu_rx *tid_agg_rx;
+	u16 start_seq_num;
+	u16 tid;
+
+	if (likely((rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_CTL))
+		return TXRX_CONTINUE;
+
+	if ((rx->fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_BACK_REQ) {
+		if (!rx->sta)
+			return TXRX_CONTINUE;
+		tid = le16_to_cpu(bar->control) >> 12;
+		tid_agg_rx = &(rx->sta->ampdu_mlme.tid_rx[tid]);
+		if (tid_agg_rx->state != HT_AGG_STATE_OPERATIONAL)
+			return TXRX_CONTINUE;
+
+		start_seq_num = le16_to_cpu(bar->start_seq_num) >> 4;
+
+		/* reset session timer */
+		if (tid_agg_rx->timeout) {
+			unsigned long expires =
+				jiffies + (tid_agg_rx->timeout / 1000) * HZ;
+			mod_timer(&tid_agg_rx->session_timer, expires);
+		}
+
+		/* manage reordering buffer according to requested */
+		/* sequence number */
+		rcu_read_lock();
+		ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, NULL,
+						 start_seq_num, 1);
+		rcu_read_unlock();
+		return TXRX_DROP;
+	}
+
+	return TXRX_CONTINUE;
+}
+
 static ieee80211_txrx_result
 ieee80211_rx_h_mgmt(struct ieee80211_txrx_data *rx)
 {
@@ -1527,6 +1577,7 @@ ieee80211_rx_handler ieee80211_rx_handlers[] =
 	ieee80211_rx_h_remove_qos_control,
 	ieee80211_rx_h_amsdu,
 	ieee80211_rx_h_data,
+	ieee80211_rx_h_ctrl,
 	ieee80211_rx_h_mgmt,
 	NULL
 };
@@ -1683,8 +1734,6 @@ void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw, struct sk_buff *skb,
 		return;
 	}
 
-	bssid = ieee80211_get_bssid(hdr, skb->len);
-
 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 		if (!netif_running(sdata->dev))
 			continue;
@@ -1692,6 +1741,7 @@ void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw, struct sk_buff *skb,
 		if (sdata->type == IEEE80211_IF_TYPE_MNTR)
 			continue;
 
+		bssid = ieee80211_get_bssid(hdr, skb->len, sdata->type);
 		rx.flags |= IEEE80211_TXRXD_RXRA_MATCH;
 		prepares = prepare_for_handlers(sdata, bssid, &rx, hdr);
 		/* prepare_for_handlers can change sta */
@@ -1767,6 +1817,10 @@ static inline u16 seq_sub(u16 sq1, u16 sq2)
 }
 
 
+/*
+ * As it function blongs to Rx path it must be called with
+ * the proper rcu_read_lock protection for its flow.
+ */
 u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
 				struct tid_ampdu_rx *tid_agg_rx,
 				struct sk_buff *skb, u16 mpdu_seq_num,

net/mac80211/util.c

@@ -127,7 +127,8 @@ void ieee80211_prepare_rates(struct ieee80211_local *local,
 	}
 }
 
-u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len)
+u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
+			enum ieee80211_if_types type)
 {
 	u16 fc;
 
@@ -159,6 +160,18 @@ u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len)
 	case IEEE80211_FTYPE_CTL:
 		if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
 			return hdr->addr1;
+		else if ((fc & IEEE80211_FCTL_STYPE) ==
+						IEEE80211_STYPE_BACK_REQ) {
+			switch (type) {
+			case IEEE80211_IF_TYPE_STA:
+				return hdr->addr2;
+			case IEEE80211_IF_TYPE_AP:
+			case IEEE80211_IF_TYPE_VLAN:
+				return hdr->addr1;
+			default:
+				return NULL;
+			}
+		}
 		else
 			return NULL;
 	}