mac80211: add support for Rx reordering offloading

Some drivers may be performing most of Tx/Rx
aggregation on their own (e.g. in firmware)
including AddBa/DelBa negotiations but may
otherwise require Rx reordering assistance.

The patch exports 2 new functions for establishing
Rx aggregation sessions in assumption device
driver has taken care of the necessary
negotiations.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
[fix endian bug]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -4552,6 +4552,40 @@ void ieee80211_stop_rx_ba_session(struct ieee80211_vif *vif, u16 ba_rx_bitmap,
  */
 void ieee80211_send_bar(struct ieee80211_vif *vif, u8 *ra, u16 tid, u16 ssn);
 
+/**
+ * ieee80211_start_rx_ba_session_offl - start a Rx BA session
+ *
+ * Some device drivers may offload part of the Rx aggregation flow including
+ * AddBa/DelBa negotiation but may otherwise be incapable of full Rx
+ * reordering.
+ *
+ * Create structures responsible for reordering so device drivers may call here
+ * when they complete AddBa negotiation.
+ *
+ * @vif: &struct ieee80211_vif pointer from the add_interface callback
+ * @addr: station mac address
+ * @tid: the rx tid
+ */
+void ieee80211_start_rx_ba_session_offl(struct ieee80211_vif *vif,
+					const u8 *addr, u16 tid);
+
+/**
+ * ieee80211_stop_rx_ba_session_offl - stop a Rx BA session
+ *
+ * Some device drivers may offload part of the Rx aggregation flow including
+ * AddBa/DelBa negotiation but may otherwise be incapable of full Rx
+ * reordering.
+ *
+ * Destroy structures responsible for reordering so device drivers may call here
+ * when they complete DelBa negotiation.
+ *
+ * @vif: &struct ieee80211_vif pointer from the add_interface callback
+ * @addr: station mac address
+ * @tid: the rx tid
+ */
+void ieee80211_stop_rx_ba_session_offl(struct ieee80211_vif *vif,
+				       const u8 *addr, u16 tid);
+
 /* Rate control API */
 
 /**

net/mac80211/agg-rx.c

@@ -224,28 +224,15 @@ static void ieee80211_send_addba_resp(struct ieee80211_sub_if_data *sdata, u8 *d
 	ieee80211_tx_skb(sdata, skb);
 }
 
-void ieee80211_process_addba_request(struct ieee80211_local *local,
-				     struct sta_info *sta,
-				     struct ieee80211_mgmt *mgmt,
-				     size_t len)
+void __ieee80211_start_rx_ba_session(struct sta_info *sta,
+				     u8 dialog_token, u16 timeout,
+				     u16 start_seq_num, u16 ba_policy, u16 tid,
+				     u16 buf_size, bool tx)
 {
+	struct ieee80211_local *local = sta->sdata->local;
 	struct tid_ampdu_rx *tid_agg_rx;
-	u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num, status;
-	u8 dialog_token;
 	int i, ret = -EOPNOTSUPP;
-
-	/* extract session parameters from addba request frame */
-	dialog_token = mgmt->u.action.u.addba_req.dialog_token;
-	timeout = le16_to_cpu(mgmt->u.action.u.addba_req.timeout);
-	start_seq_num =
-		le16_to_cpu(mgmt->u.action.u.addba_req.start_seq_num) >> 4;
-
-	capab = le16_to_cpu(mgmt->u.action.u.addba_req.capab);
-	ba_policy = (capab & IEEE80211_ADDBA_PARAM_POLICY_MASK) >> 1;
-	tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
-	buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
-
-	status = WLAN_STATUS_REQUEST_DECLINED;
+	u16 status = WLAN_STATUS_REQUEST_DECLINED;
 
 	if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
 		ht_dbg(sta->sdata,
@@ -264,7 +251,7 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
 		status = WLAN_STATUS_INVALID_QOS_PARAM;
 		ht_dbg_ratelimited(sta->sdata,
 				   "AddBA Req with bad params from %pM on tid %u. policy %d, buffer size %d\n",
-				   mgmt->sa, tid, ba_policy, buf_size);
+				   sta->sta.addr, tid, ba_policy, buf_size);
 		goto end_no_lock;
 	}
 	/* determine default buffer size */
@@ -281,7 +268,7 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
 	if (sta->ampdu_mlme.tid_rx[tid]) {
 		ht_dbg_ratelimited(sta->sdata,
 				   "unexpected AddBA Req from %pM on tid %u\n",
-				   mgmt->sa, tid);
+				   sta->sta.addr, tid);
 
 		/* delete existing Rx BA session on the same tid */
 		___ieee80211_stop_rx_ba_session(sta, tid, WLAN_BACK_RECIPIENT,
@@ -353,6 +340,74 @@ end:
 	mutex_unlock(&sta->ampdu_mlme.mtx);
 
 end_no_lock:
-	ieee80211_send_addba_resp(sta->sdata, sta->sta.addr, tid,
-				  dialog_token, status, 1, buf_size, timeout);
+	if (tx)
+		ieee80211_send_addba_resp(sta->sdata, sta->sta.addr, tid,
+					  dialog_token, status, 1, buf_size,
+					  timeout);
+}
+
+void ieee80211_process_addba_request(struct ieee80211_local *local,
+				     struct sta_info *sta,
+				     struct ieee80211_mgmt *mgmt,
+				     size_t len)
+{
+	u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num;
+	u8 dialog_token;
+
+	/* extract session parameters from addba request frame */
+	dialog_token = mgmt->u.action.u.addba_req.dialog_token;
+	timeout = le16_to_cpu(mgmt->u.action.u.addba_req.timeout);
+	start_seq_num =
+		le16_to_cpu(mgmt->u.action.u.addba_req.start_seq_num) >> 4;
+
+	capab = le16_to_cpu(mgmt->u.action.u.addba_req.capab);
+	ba_policy = (capab & IEEE80211_ADDBA_PARAM_POLICY_MASK) >> 1;
+	tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
+	buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
+
+	__ieee80211_start_rx_ba_session(sta, dialog_token, timeout,
+					start_seq_num, ba_policy, tid,
+					buf_size, true);
+}
+
+void ieee80211_start_rx_ba_session_offl(struct ieee80211_vif *vif,
+					const u8 *addr, u16 tid)
+{
+	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_rx_agg *rx_agg;
+	struct sk_buff *skb = dev_alloc_skb(0);
+
+	if (unlikely(!skb))
+		return;
+
+	rx_agg = (struct ieee80211_rx_agg *) &skb->cb;
+	memcpy(&rx_agg->addr, addr, ETH_ALEN);
+	rx_agg->tid = tid;
+
+	skb->pkt_type = IEEE80211_SDATA_QUEUE_RX_AGG_START;
+	skb_queue_tail(&sdata->skb_queue, skb);
+	ieee80211_queue_work(&local->hw, &sdata->work);
+}
+EXPORT_SYMBOL(ieee80211_start_rx_ba_session_offl);
+
+void ieee80211_stop_rx_ba_session_offl(struct ieee80211_vif *vif,
+				       const u8 *addr, u16 tid)
+{
+	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_rx_agg *rx_agg;
+	struct sk_buff *skb = dev_alloc_skb(0);
+
+	if (unlikely(!skb))
+		return;
+
+	rx_agg = (struct ieee80211_rx_agg *) &skb->cb;
+	memcpy(&rx_agg->addr, addr, ETH_ALEN);
+	rx_agg->tid = tid;
+
+	skb->pkt_type = IEEE80211_SDATA_QUEUE_RX_AGG_STOP;
+	skb_queue_tail(&sdata->skb_queue, skb);
+	ieee80211_queue_work(&local->hw, &sdata->work);
 }
+EXPORT_SYMBOL(ieee80211_stop_rx_ba_session_offl);

net/mac80211/ieee80211_i.h

@@ -925,10 +925,17 @@ ieee80211_vif_get_shift(struct ieee80211_vif *vif)
 	return shift;
 }
 
+struct ieee80211_rx_agg {
+	u8 addr[ETH_ALEN];
+	u16 tid;
+};
+
 enum sdata_queue_type {
 	IEEE80211_SDATA_QUEUE_TYPE_FRAME	= 0,
 	IEEE80211_SDATA_QUEUE_AGG_START		= 1,
 	IEEE80211_SDATA_QUEUE_AGG_STOP		= 2,
+	IEEE80211_SDATA_QUEUE_RX_AGG_START	= 3,
+	IEEE80211_SDATA_QUEUE_RX_AGG_STOP	= 4,
 };
 
 enum {
@@ -1577,6 +1584,10 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 				     u16 initiator, u16 reason, bool stop);
 void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 				    u16 initiator, u16 reason, bool stop);
+void __ieee80211_start_rx_ba_session(struct sta_info *sta,
+				     u8 dialog_token, u16 timeout,
+				     u16 start_seq_num, u16 ba_policy, u16 tid,
+				     u16 buf_size, bool tx);
 void ieee80211_sta_tear_down_BA_sessions(struct sta_info *sta,
 					 enum ieee80211_agg_stop_reason reason);
 void ieee80211_process_delba(struct ieee80211_sub_if_data *sdata,

net/mac80211/iface.c

@@ -1140,6 +1140,7 @@ static void ieee80211_iface_work(struct work_struct *work)
 	struct sk_buff *skb;
 	struct sta_info *sta;
 	struct ieee80211_ra_tid *ra_tid;
+	struct ieee80211_rx_agg *rx_agg;
 
 	if (!ieee80211_sdata_running(sdata))
 		return;
@@ -1167,6 +1168,34 @@ static void ieee80211_iface_work(struct work_struct *work)
 			ra_tid = (void *)&skb->cb;
 			ieee80211_stop_tx_ba_cb(&sdata->vif, ra_tid->ra,
 						ra_tid->tid);
+		} else if (skb->pkt_type == IEEE80211_SDATA_QUEUE_RX_AGG_START) {
+			rx_agg = (void *)&skb->cb;
+			mutex_lock(&local->sta_mtx);
+			sta = sta_info_get_bss(sdata, rx_agg->addr);
+			if (sta) {
+				u16 last_seq;
+
+				last_seq = le16_to_cpu(
+					sta->last_seq_ctrl[rx_agg->tid]);
+
+				__ieee80211_start_rx_ba_session(sta,
+						0, 0,
+						ieee80211_sn_inc(last_seq),
+						1, rx_agg->tid,
+						IEEE80211_MAX_AMPDU_BUF,
+						false);
+			}
+			mutex_unlock(&local->sta_mtx);
+		} else if (skb->pkt_type == IEEE80211_SDATA_QUEUE_RX_AGG_STOP) {
+			rx_agg = (void *)&skb->cb;
+			mutex_lock(&local->sta_mtx);
+			sta = sta_info_get_bss(sdata, rx_agg->addr);
+			if (sta)
+				__ieee80211_stop_rx_ba_session(sta,
+							rx_agg->tid,
+							WLAN_BACK_RECIPIENT, 0,
+							false);
+			mutex_unlock(&local->sta_mtx);
 		} else if (ieee80211_is_action(mgmt->frame_control) &&
 			   mgmt->u.action.category == WLAN_CATEGORY_BACK) {
 			int len = skb->len;