mac80211: allow software PS-Poll/U-APSD with AP_LINK_PS

When using RSS, frames might not be processed in the correct order,
and thus AP_LINK_PS must be used; most likely with firmware keeping
track of the powersave state, this is the case in iwlwifi now.

In this case, the driver can use ieee80211_sta_ps_transition() to
still have mac80211 manage powersave buffering. However, for U-APSD
and PS-Poll this isn't sufficient. If the device can't manage that
entirely on its own, mac80211's code should be used.

To allow this, export two functions: ieee80211_sta_uapsd_trigger()
and ieee80211_sta_pspoll().

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 71 insertions, 26 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index ce2f6e3be3cf..be30b0549b88 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -3996,6 +3996,33 @@ static inline int ieee80211_sta_ps_transition_ni(struct ieee80211_sta *sta,
         return ret;
 }
 
+/**
+ * ieee80211_sta_pspoll - PS-Poll frame received
+ * @sta: currently connected station
+ *
+ * When operating in AP mode with the %IEEE80211_HW_AP_LINK_PS flag set,
+ * use this function to inform mac80211 that a PS-Poll frame from a
+ * connected station was received.
+ * This must be used in conjunction with ieee80211_sta_ps_transition()
+ * and possibly ieee80211_sta_uapsd_trigger(); calls to all three must
+ * be serialized.
+ */
+void ieee80211_sta_pspoll(struct ieee80211_sta *sta);
+
+/**
+ * ieee80211_sta_uapsd_trigger - (potential) U-APSD trigger frame received
+ * @sta: currently connected station
+ * @tid: TID of the received (potential) trigger frame
+ *
+ * When operating in AP mode with the %IEEE80211_HW_AP_LINK_PS flag set,
+ * use this function to inform mac80211 that a (potential) trigger frame
+ * from a connected station was received.
+ * This must be used in conjunction with ieee80211_sta_ps_transition()
+ * and possibly ieee80211_sta_pspoll(); calls to all three must be
+ * serialized.
+ */
+void ieee80211_sta_uapsd_trigger(struct ieee80211_sta *sta, u8 tid);
+
 /*
  * The TX headroom reserved by mac80211 for its own tx_status functions.
  * This is enough for the radiotap header.
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index c5678703921e..5e65e838992a 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1319,13 +1319,52 @@ int ieee80211_sta_ps_transition(struct ieee80211_sta *pubsta, bool start)
 }
 EXPORT_SYMBOL(ieee80211_sta_ps_transition);
 
+void ieee80211_sta_pspoll(struct ieee80211_sta *pubsta)
+{
+        struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
+
+        if (test_sta_flag(sta, WLAN_STA_SP))
+                return;
+
+        if (!test_sta_flag(sta, WLAN_STA_PS_DRIVER))
+                ieee80211_sta_ps_deliver_poll_response(sta);
+        else
+                set_sta_flag(sta, WLAN_STA_PSPOLL);
+}
+EXPORT_SYMBOL(ieee80211_sta_pspoll);
+
+void ieee80211_sta_uapsd_trigger(struct ieee80211_sta *pubsta, u8 tid)
+{
+        struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
+        u8 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 (!(sta->sta.uapsd_queues & BIT(ac)))
+                return;
+
+        /* if we are in a service period, do nothing */
+        if (test_sta_flag(sta, WLAN_STA_SP))
+                return;
+
+        if (!test_sta_flag(sta, WLAN_STA_PS_DRIVER))
+                ieee80211_sta_ps_deliver_uapsd(sta);
+        else
+                set_sta_flag(sta, WLAN_STA_UAPSD);
+}
+EXPORT_SYMBOL(ieee80211_sta_uapsd_trigger);
+
 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)
                 return RX_CONTINUE;
@@ -1351,12 +1390,7 @@ ieee80211_rx_h_uapsd_and_pspoll(struct ieee80211_rx_data *rx)
                 return RX_CONTINUE;
 
         if (unlikely(ieee80211_is_pspoll(hdr->frame_control))) {
-                if (!test_sta_flag(rx->sta, WLAN_STA_SP)) {
-                        if (!test_sta_flag(rx->sta, WLAN_STA_PS_DRIVER))
-                                ieee80211_sta_ps_deliver_poll_response(rx->sta);
-                        else
-                                set_sta_flag(rx->sta, WLAN_STA_PSPOLL);
-                }
+                ieee80211_sta_pspoll(&rx->sta->sta);
 
                 /* Free PS Poll skb here instead of returning RX_DROP that would
                  * count as an dropped frame. */
@@ -1368,27 +1402,11 @@ ieee80211_rx_h_uapsd_and_pspoll(struct ieee80211_rx_data *rx)
                    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];
+                u8 tid;
 
-                /*
-                 * 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_flag(rx->sta, WLAN_STA_SP))
-                        return RX_CONTINUE;
+                tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
 
-                if (!test_sta_flag(rx->sta, WLAN_STA_PS_DRIVER))
-                        ieee80211_sta_ps_deliver_uapsd(rx->sta);
-                else
-                        set_sta_flag(rx->sta, WLAN_STA_UAPSD);
+                ieee80211_sta_uapsd_trigger(&rx->sta->sta, tid);
         }
 
         return RX_CONTINUE;