mac80211: implement uAPSD

Add uAPSD support to mac80211. This is probably not
possible with all devices, so advertising it with
the cfg80211 flag will be left up to drivers that
want it.

Due to my previous patches it is now a fairly
straight-forward extension. Drivers need to have
accurate TX status reporting for the EOSP frame.
For drivers that buffer themselves, the provided
APIs allow releasing the right number of frames,
but then drivers need to set EOSP and more-data
themselves. This is documented in more detail in
the new code itself.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 125 insertions, 45 deletions

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index b3f8419..f9079e4 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -248,6 +248,9 @@ static void sta_unblock(struct work_struct *wk)
 	else if (test_and_clear_sta_flags(sta, WLAN_STA_PSPOLL)) {
 		clear_sta_flags(sta, WLAN_STA_PS_DRIVER);
 		ieee80211_sta_ps_deliver_poll_response(sta);
+	} else if (test_and_clear_sta_flags(sta, WLAN_STA_UAPSD)) {
+		clear_sta_flags(sta, WLAN_STA_PS_DRIVER);
+		ieee80211_sta_ps_deliver_uapsd(sta);
 	} else
 		clear_sta_flags(sta, WLAN_STA_PS_DRIVER);
 }
@@ -1117,6 +1120,8 @@ void ieee80211_sta_ps_deliver_wakeup(struct sta_info *sta)
 	struct sk_buff_head pending;
 	int filtered = 0, buffered = 0, ac;
 
+	clear_sta_flags(sta, WLAN_STA_SP);
+
 	BUILD_BUG_ON(BITS_TO_LONGS(STA_TID_NUM) > 1);
 	sta->driver_buffered_tids = 0;
 
@@ -1152,32 +1157,28 @@ void ieee80211_sta_ps_deliver_wakeup(struct sta_info *sta)
 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
 }
 
-void ieee80211_sta_ps_deliver_poll_response(struct sta_info *sta)
+static void
+ieee80211_sta_ps_deliver_response(struct sta_info *sta,
+				  int n_frames, u8 ignored_acs,
+				  enum ieee80211_frame_release_type reason)
 {
 	struct ieee80211_sub_if_data *sdata = sta->sdata;
 	struct ieee80211_local *local = sdata->local;
-	struct sk_buff *skb = NULL;
 	bool found = false;
 	bool more_data = false;
 	int ac;
 	unsigned long driver_release_tids = 0;
-	u8 ignore_for_response = sta->sta.uapsd_queues;
+	struct sk_buff_head frames;
 
-	/*
-	 * If all ACs are delivery-enabled then we should reply
-	 * from any of them, if only some are enabled we reply
-	 * only from the non-enabled ones.
-	 */
-	if (ignore_for_response == BIT(IEEE80211_NUM_ACS) - 1)
-		ignore_for_response = 0;
+	__skb_queue_head_init(&frames);
 
 	/*
-	 * Get response frame and more data bit for it.
+	 * Get response frame(s) and more data bit for it.
 	 */
 	for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
 		unsigned long tids;
 
-		if (ignore_for_response & BIT(ac))
+		if (ignored_acs & BIT(ac))
 			continue;
 
 		tids = ieee80211_tids_for_ac(ac);
@@ -1187,14 +1188,22 @@ void ieee80211_sta_ps_deliver_poll_response(struct sta_info *sta)
 			if (driver_release_tids) {
 				found = true;
 			} else {
-				skb = skb_dequeue(&sta->tx_filtered[ac]);
-				if (!skb) {
-					skb = skb_dequeue(&sta->ps_tx_buf[ac]);
-					if (skb)
-						local->total_ps_buffered--;
-				}
-				if (skb)
+				struct sk_buff *skb;
+
+				while (n_frames > 0) {
+					skb = skb_dequeue(&sta->tx_filtered[ac]);
+					if (!skb) {
+						skb = skb_dequeue(
+							&sta->ps_tx_buf[ac]);
+						if (skb)
+							local->total_ps_buffered--;
+					}
+					if (!skb)
+						break;
+					n_frames--;
 					found = true;
+					__skb_queue_tail(&frames, skb);
+				}
 			}
 
 			/*
@@ -1202,7 +1211,8 @@ void ieee80211_sta_ps_deliver_poll_response(struct sta_info *sta)
 			 * certainly there's more data if we release just a
 			 * single frame now (from a single TID).
 			 */
-			if (hweight16(driver_release_tids) > 1) {
+			if (reason == IEEE80211_FRAME_RELEASE_PSPOLL &&
+			    hweight16(driver_release_tids) > 1) {
 				more_data = true;
 				driver_release_tids =
 					BIT(ffs(driver_release_tids) - 1);
@@ -1225,38 +1235,56 @@ void ieee80211_sta_ps_deliver_poll_response(struct sta_info *sta)
 		 *	  Should we send it a null-func frame indicating we
 		 *	  have nothing buffered for it?
 		 */
-		printk(KERN_DEBUG "%s: STA %pM sent PS Poll even "
-		       "though there are no buffered frames for it\n",
-		       sdata->name, sta->sta.addr);
+		if (reason == IEEE80211_FRAME_RELEASE_PSPOLL)
+			printk(KERN_DEBUG "%s: STA %pM sent PS Poll even "
+			       "though there are no buffered frames for it\n",
+			       sdata->name, sta->sta.addr);
 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
 
 		return;
 	}
 
-	if (skb) {
-		struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
-		struct ieee80211_hdr *hdr =
-			(struct ieee80211_hdr *) skb->data;
+	if (!driver_release_tids) {
+		struct sk_buff_head pending;
+		struct sk_buff *skb;
 
-		/*
-		 * Tell TX path to send this frame even though the STA may
-		 * still remain is PS mode after this frame exchange.
-		 */
-		info->flags |= IEEE80211_TX_CTL_PSPOLL_RESPONSE;
+		skb_queue_head_init(&pending);
 
-#ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
-		printk(KERN_DEBUG "STA %pM aid %d: PS Poll\n",
-		       sta->sta.addr, sta->sta.aid);
-#endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
+		while ((skb = __skb_dequeue(&frames))) {
+			struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+			struct ieee80211_hdr *hdr = (void *) skb->data;
 
-		/* Use MoreData flag to indicate whether there are more
-		 * buffered frames for this STA */
-		if (!more_data)
-			hdr->frame_control &= cpu_to_le16(~IEEE80211_FCTL_MOREDATA);
-		else
-			hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_MOREDATA);
+			/*
+			 * Tell TX path to send this frame even though the
+			 * STA may still remain is PS mode after this frame
+			 * exchange.
+			 */
+			info->flags |= IEEE80211_TX_CTL_POLL_RESPONSE;
+
+			/*
+			 * Use MoreData flag to indicate whether there are
+			 * more buffered frames for this STA
+			 */
+			if (!more_data)
+				hdr->frame_control &=
+					cpu_to_le16(~IEEE80211_FCTL_MOREDATA);
+			else
+				hdr->frame_control |=
+					cpu_to_le16(IEEE80211_FCTL_MOREDATA);
+
+			if (reason == IEEE80211_FRAME_RELEASE_UAPSD &&
+			    skb_queue_empty(&frames)) {
+				/* set EOSP for the frame */
+				u8 *p = ieee80211_get_qos_ctl(hdr);
+				*p |= IEEE80211_QOS_CTL_EOSP;
+				info->flags |= IEEE80211_TX_STATUS_EOSP |
+					       IEEE80211_TX_CTL_REQ_TX_STATUS;
+			}
 
-		ieee80211_add_pending_skb(local, skb);
+			__skb_queue_tail(&pending, skb);
+		}
+
+		ieee80211_add_pending_skbs(local, &pending);
 
 		sta_info_recalc_tim(sta);
 	} else {
@@ -1271,8 +1299,7 @@ void ieee80211_sta_ps_deliver_poll_response(struct sta_info *sta)
 		 * needs to be set anyway.
 		 */
 		drv_release_buffered_frames(local, sta, driver_release_tids,
-					    1, IEEE80211_FRAME_RELEASE_PSPOLL,
-					    more_data);
+					    n_frames, reason, more_data);
 
 		/*
 		 * Note that we don't recalculate the TIM bit here as it would
@@ -1285,6 +1312,59 @@ void ieee80211_sta_ps_deliver_poll_response(struct sta_info *sta)
 	}
 }
 
+void ieee80211_sta_ps_deliver_poll_response(struct sta_info *sta)
+{
+	u8 ignore_for_response = sta->sta.uapsd_queues;
+
+	/*
+	 * If all ACs are delivery-enabled then we should reply
+	 * from any of them, if only some are enabled we reply
+	 * only from the non-enabled ones.
+	 */
+	if (ignore_for_response == BIT(IEEE80211_NUM_ACS) - 1)
+		ignore_for_response = 0;
+
+	ieee80211_sta_ps_deliver_response(sta, 1, ignore_for_response,
+					  IEEE80211_FRAME_RELEASE_PSPOLL);
+}
+
+void ieee80211_sta_ps_deliver_uapsd(struct sta_info *sta)
+{
+	int n_frames = sta->sta.max_sp;
+	u8 delivery_enabled = sta->sta.uapsd_queues;
+
+	/*
+	 * If we ever grow support for TSPEC this might happen if
+	 * the TSPEC update from hostapd comes in between a trigger
+	 * frame setting WLAN_STA_UAPSD in the RX path and this
+	 * actually getting called.
+	 */
+	if (!delivery_enabled)
+		return;
+
+	/* Ohh, finally, the service period starts :-) */
+	set_sta_flags(sta, WLAN_STA_SP);
+
+	switch (sta->sta.max_sp) {
+	case 1:
+		n_frames = 2;
+		break;
+	case 2:
+		n_frames = 4;
+		break;
+	case 3:
+		n_frames = 6;
+		break;
+	case 0:
+		/* XXX: what is a good value? */
+		n_frames = 8;
+		break;
+	}
+
+	ieee80211_sta_ps_deliver_response(sta, n_frames, ~delivery_enabled,
+					  IEEE80211_FRAME_RELEASE_UAPSD);
+}
+
 void ieee80211_sta_block_awake(struct ieee80211_hw *hw,
 			       struct ieee80211_sta *pubsta, bool block)
 {