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, 74 insertions, 28 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index db46601e50bf..9a703f00b5fb 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1163,6 +1163,79 @@ int ieee80211_sta_ps_transition(struct ieee80211_sta *sta, bool start)
 EXPORT_SYMBOL(ieee80211_sta_ps_transition);
 
 static ieee80211_rx_result debug_noinline
+ieee80211_rx_h_uapsd_and_pspoll(struct ieee80211_rx_data *rx)
+{
+	struct ieee80211_sub_if_data *sdata = rx->sdata;
+	struct ieee80211_hdr *hdr = (void *)rx->skb->data;
+	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
+	int tid, ac;
+
+	if (!rx->sta || !(status->rx_flags & IEEE80211_RX_RA_MATCH))
+		return RX_CONTINUE;
+
+	if (sdata->vif.type != NL80211_IFTYPE_AP &&
+	    sdata->vif.type != NL80211_IFTYPE_AP_VLAN)
+		return RX_CONTINUE;
+
+	/*
+	 * The device handles station powersave, so don't do anything about
+	 * uAPSD and PS-Poll frames (the latter shouldn't even come up from
+	 * it to mac80211 since they're handled.)
+	 */
+	if (sdata->local->hw.flags & IEEE80211_HW_AP_LINK_PS)
+		return RX_CONTINUE;
+
+	/*
+	 * Don't do anything if the station isn't already asleep. In
+	 * the uAPSD case, the station will probably be marked asleep,
+	 * in the PS-Poll case the station must be confused ...
+	 */
+	if (!test_sta_flags(rx->sta, WLAN_STA_PS_STA))
+		return RX_CONTINUE;
+
+	if (unlikely(ieee80211_is_pspoll(hdr->frame_control))) {
+		if (!test_sta_flags(rx->sta, WLAN_STA_PS_DRIVER))
+			ieee80211_sta_ps_deliver_poll_response(rx->sta);
+		else
+			set_sta_flags(rx->sta, WLAN_STA_PSPOLL);
+
+		/* Free PS Poll skb here instead of returning RX_DROP that would
+		 * count as an dropped frame. */
+		dev_kfree_skb(rx->skb);
+
+		return RX_QUEUED;
+	} else if (!ieee80211_has_morefrags(hdr->frame_control) &&
+		   !(status->rx_flags & IEEE80211_RX_DEFERRED_RELEASE) &&
+		   ieee80211_has_pm(hdr->frame_control) &&
+		   (ieee80211_is_data_qos(hdr->frame_control) ||
+		    ieee80211_is_qos_nullfunc(hdr->frame_control))) {
+		tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
+		ac = ieee802_1d_to_ac[tid & 7];
+
+		/*
+		 * If this AC is not trigger-enabled do nothing.
+		 *
+		 * NB: This could/should check a separate bitmap of trigger-
+		 * enabled queues, but for now we only implement uAPSD w/o
+		 * TSPEC changes to the ACs, so they're always the same.
+		 */
+		if (!(rx->sta->sta.uapsd_queues & BIT(ac)))
+			return RX_CONTINUE;
+
+		/* if we are in a service period, do nothing */
+		if (test_sta_flags(rx->sta, WLAN_STA_SP))
+			return RX_CONTINUE;
+
+		if (!test_sta_flags(rx->sta, WLAN_STA_PS_DRIVER))
+			ieee80211_sta_ps_deliver_uapsd(rx->sta);
+		else
+			set_sta_flags(rx->sta, WLAN_STA_UAPSD);
+	}
+
+	return RX_CONTINUE;
+}
+
+static ieee80211_rx_result debug_noinline
 ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
 {
 	struct sta_info *sta = rx->sta;
@@ -1473,33 +1546,6 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
 }
 
 static ieee80211_rx_result debug_noinline
-ieee80211_rx_h_ps_poll(struct ieee80211_rx_data *rx)
-{
-	struct ieee80211_sub_if_data *sdata = rx->sdata;
-	__le16 fc = ((struct ieee80211_hdr *)rx->skb->data)->frame_control;
-	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
-
-	if (likely(!rx->sta || !ieee80211_is_pspoll(fc) ||
-		   !(status->rx_flags & IEEE80211_RX_RA_MATCH)))
-		return RX_CONTINUE;
-
-	if ((sdata->vif.type != NL80211_IFTYPE_AP) &&
-	    (sdata->vif.type != NL80211_IFTYPE_AP_VLAN))
-		return RX_DROP_UNUSABLE;
-
-	if (!test_sta_flags(rx->sta, WLAN_STA_PS_DRIVER))
-		ieee80211_sta_ps_deliver_poll_response(rx->sta);
-	else
-		set_sta_flags(rx->sta, WLAN_STA_PSPOLL);
-
-	/* Free PS Poll skb here instead of returning RX_DROP that would
-	 * count as an dropped frame. */
-	dev_kfree_skb(rx->skb);
-
-	return RX_QUEUED;
-}
-
-static ieee80211_rx_result debug_noinline
 ieee80211_rx_h_remove_qos_control(struct ieee80211_rx_data *rx)
 {
 	u8 *data = rx->skb->data;
@@ -2567,9 +2613,9 @@ static void ieee80211_rx_handlers(struct ieee80211_rx_data *rx)
 
 		CALL_RXH(ieee80211_rx_h_decrypt)
 		CALL_RXH(ieee80211_rx_h_check_more_data)
+		CALL_RXH(ieee80211_rx_h_uapsd_and_pspoll)
 		CALL_RXH(ieee80211_rx_h_sta_process)
 		CALL_RXH(ieee80211_rx_h_defragment)
-		CALL_RXH(ieee80211_rx_h_ps_poll)
 		CALL_RXH(ieee80211_rx_h_michael_mic_verify)
 		/* must be after MMIC verify so header is counted in MPDU mic */
 #ifdef CONFIG_MAC80211_MESH