mac80211: add WMM admission control support

Use the currently existing APIs between mac80211 and the low
level driver to implement WMM admission control.

The low level driver needs to report the media time used by
each transmitted packet in ieee80211_tx_status. Based on that
information, mac80211 will modify the QoS parameters of the
admission controlled Access Category when the limit is
reached. Once the original QoS parameters can be restored,
mac80211 will do so.

One issue with this approach is that management frames will
also erroneously be downgraded, but the upside is that the
implementation is simple. In the future, it can be extended
to driver- or device-based implementations that are better.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 37 insertions, 1 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 78d6121eb372..60063be057d0 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -399,6 +399,24 @@ struct ieee80211_mgd_assoc_data {
         u8 ie[];
 };
 
+struct ieee80211_sta_tx_tspec {
+        /* timestamp of the first packet in the time slice */
+        unsigned long time_slice_start;
+
+        u32 admitted_time; /* in usecs, unlike over the air */
+        u8 tsid;
+        s8 up; /* signed to be able to invalidate with -1 during teardown */
+
+        /* consumed TX time in microseconds in the time slice */
+        u32 consumed_tx_time;
+        enum {
+                TX_TSPEC_ACTION_NONE = 0,
+                TX_TSPEC_ACTION_DOWNGRADE,
+                TX_TSPEC_ACTION_STOP_DOWNGRADE,
+        } action;
+        bool downgraded;
+};
+
 struct ieee80211_if_managed {
         struct timer_list timer;
         struct timer_list conn_mon_timer;
@@ -509,6 +527,16 @@ struct ieee80211_if_managed {
 
         u8 tdls_peer[ETH_ALEN] __aligned(2);
         struct delayed_work tdls_peer_del_work;
+
+        /* WMM-AC TSPEC support */
+        struct ieee80211_sta_tx_tspec tx_tspec[IEEE80211_NUM_ACS];
+        /* Use a separate work struct so that we can do something here
+         * while the sdata->work is flushing the queues, for example.
+         * otherwise, in scenarios where we hardly get any traffic out
+         * on the BE queue, but there's a lot of VO traffic, we might
+         * get stuck in a downgraded situation and flush takes forever.
+         */
+        struct delayed_work tx_tspec_wk;
 };
 
 struct ieee80211_if_ibss {
@@ -1459,6 +1487,7 @@ void ieee80211_mgd_conn_tx_status(struct ieee80211_sub_if_data *sdata,
                                   __le16 fc, bool acked);
 void ieee80211_mgd_quiesce(struct ieee80211_sub_if_data *sdata);
 void ieee80211_sta_restart(struct ieee80211_sub_if_data *sdata);
+void ieee80211_sta_handle_tspec_ac_params(struct ieee80211_sub_if_data *sdata);
 
 /* IBSS code */
 void ieee80211_ibss_notify_scan_completed(struct ieee80211_local *local);
@@ -1763,6 +1792,13 @@ static inline bool ieee80211_rx_reorder_ready(struct sk_buff_head *frames)
         return true;
 }
 
+extern const int ieee802_1d_to_ac[8];
+
+static inline int ieee80211_ac_from_tid(int tid)
+{
+        return ieee802_1d_to_ac[tid & 7];
+}
+
 void ieee80211_dynamic_ps_enable_work(struct work_struct *work);
 void ieee80211_dynamic_ps_disable_work(struct work_struct *work);
 void ieee80211_dynamic_ps_timer(unsigned long data);
@@ -1772,7 +1808,7 @@ void ieee80211_send_nullfunc(struct ieee80211_local *local,
 void ieee80211_sta_rx_notify(struct ieee80211_sub_if_data *sdata,
                              struct ieee80211_hdr *hdr);
 void ieee80211_sta_tx_notify(struct ieee80211_sub_if_data *sdata,
-                             struct ieee80211_hdr *hdr, bool ack);
+                             struct ieee80211_hdr *hdr, bool ack, u16 tx_time);
 
 void ieee80211_wake_queues_by_reason(struct ieee80211_hw *hw,
                                      unsigned long queues,