mac80211: Handle the CSA counters correctly

Make the beacon CSA counters part of ieee80211_mutable_offsets and don't
decrement CSA counters when generating a beacon template. This permits the
driver to offload the CSA counters handling. Since mac80211 updates the probe
responses with the correct counter, the driver should sync the counter's value
with mac80211 using ieee80211_csa_update_counter function.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 22 insertions, 1 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index e6521261a585..982d2cd80166 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -3411,14 +3411,20 @@ void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw,
  */
 void ieee80211_report_low_ack(struct ieee80211_sta *sta, u32 num_packets);
 
+#define IEEE80211_MAX_CSA_COUNTERS_NUM 2
+
 /**
  * struct ieee80211_mutable_offsets - mutable beacon offsets
  * @tim_offset: position of TIM element
  * @tim_length: size of TIM element
+ * @csa_offs: array of IEEE80211_MAX_CSA_COUNTERS_NUM offsets to CSA counters.
+ *      This array can contain zero values which should be ignored.
  */
 struct ieee80211_mutable_offsets {
         u16 tim_offset;
         u16 tim_length;
+
+        u16 csa_counter_offs[IEEE80211_MAX_CSA_COUNTERS_NUM];
 };
 
 /**
@@ -3433,7 +3439,8 @@ struct ieee80211_mutable_offsets {
  *
  * This function should be used if the beacon frames are generated by the
  * device, and then the driver must use the returned beacon as the template
- * The driver is responsible to update the DTIM count.
+ * The driver or the device are responsible to update the DTIM and, when
+ * applicable, the CSA count.
  *
  * The driver is responsible for freeing the returned skb.
  *
@@ -3486,6 +3493,20 @@ static inline struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw,
 }
 
 /**
+ * ieee80211_csa_update_counter - request mac80211 to decrement the csa counter
+ * @vif: &struct ieee80211_vif pointer from the add_interface callback.
+ *
+ * The csa counter should be updated after each beacon transmission.
+ * This function is called implicitly when
+ * ieee80211_beacon_get/ieee80211_beacon_get_tim are called, however if the
+ * beacon frames are generated by the device, the driver should call this
+ * function after each beacon transmission to sync mac80211's csa counters.
+ *
+ * Return: new csa counter value
+ */
+u8 ieee80211_csa_update_counter(struct ieee80211_vif *vif);
+
+/**
  * ieee80211_csa_finish - notify mac80211 about channel switch
  * @vif: &struct ieee80211_vif pointer from the add_interface callback.
  *