mac80211: add helper functions for tracking P2P NoA state

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 531785f5819ecb0ba0e665dd9be444ea8276b03d..f838af816b56cd26909752b650178450c9e47eef 100644 (file)
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -4652,4 +4652,51 @@ bool ieee80211_tx_prepare_skb(struct ieee80211_hw *hw,
                              struct ieee80211_vif *vif, struct sk_buff *skb,
                              int band, struct ieee80211_sta **sta);
 
+/**
+ * struct ieee80211_noa_data - holds temporary data for tracking P2P NoA state
+ *
+ * @next_tsf: TSF timestamp of the next absent state change
+ * @has_next_tsf: next absent state change event pending
+ *
+ * @absent: descriptor bitmask, set if GO is currently absent
+ *
+ * private:
+ *
+ * @count: count fields from the NoA descriptors
+ * @desc: adjusted data from the NoA
+ */
+struct ieee80211_noa_data {
+       u32 next_tsf;
+       bool has_next_tsf;
+
+       u8 absent;
+
+       u8 count[IEEE80211_P2P_NOA_DESC_MAX];
+       struct {
+               u32 start;
+               u32 duration;
+               u32 interval;
+       } desc[IEEE80211_P2P_NOA_DESC_MAX];
+};
+
+/**
+ * ieee80211_parse_p2p_noa - initialize NoA tracking data from P2P IE
+ *
+ * @attr: P2P NoA IE
+ * @data: NoA tracking data
+ * @tsf: current TSF timestamp
+ *
+ * Return: number of successfully parsed descriptors
+ */
+int ieee80211_parse_p2p_noa(const struct ieee80211_p2p_noa_attr *attr,
+                           struct ieee80211_noa_data *data, u32 tsf);
+
+/**
+ * ieee80211_update_p2p_noa - get next pending P2P GO absent state change
+ *
+ * @data: NoA tracking data
+ * @tsf: current TSF timestamp
+ */
+void ieee80211_update_p2p_noa(struct ieee80211_noa_data *data, u32 tsf);
+
 #endif /* MAC80211_H */

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index ed93504d24b88d087dee1f5368308659043b5a19..df00f1978a77574857a9e8cf5c37cad66ce3e487 100644 (file)
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2594,3 +2594,143 @@ int ieee80211_cs_headroom(struct ieee80211_local *local,
 
        return headroom;
 }
+
+static bool
+ieee80211_extend_noa_desc(struct ieee80211_noa_data *data, u32 tsf, int i)
+{
+       s32 end = data->desc[i].start + data->desc[i].duration - (tsf + 1);
+       int skip;
+
+       if (end > 0)
+               return false;
+
+       /* End time is in the past, check for repetitions */
+       skip = DIV_ROUND_UP(-end, data->desc[i].interval);
+       if (data->count[i] < 255) {
+               if (data->count[i] <= skip) {
+                       data->count[i] = 0;
+                       return false;
+               }
+
+               data->count[i] -= skip;
+       }
+
+       data->desc[i].start += skip * data->desc[i].interval;
+
+       return true;
+}
+
+static bool
+ieee80211_extend_absent_time(struct ieee80211_noa_data *data, u32 tsf,
+                            s32 *offset)
+{
+       bool ret = false;
+       int i;
+
+       for (i = 0; i < IEEE80211_P2P_NOA_DESC_MAX; i++) {
+               s32 cur;
+
+               if (!data->count[i])
+                       continue;
+
+               if (ieee80211_extend_noa_desc(data, tsf + *offset, i))
+                       ret = true;
+
+               cur = data->desc[i].start - tsf;
+               if (cur > *offset)
+                       continue;
+
+               cur = data->desc[i].start + data->desc[i].duration - tsf;
+               if (cur > *offset)
+                       *offset = cur;
+       }
+
+       return ret;
+}
+
+static u32
+ieee80211_get_noa_absent_time(struct ieee80211_noa_data *data, u32 tsf)
+{
+       s32 offset = 0;
+       int tries = 0;
+       /*
+        * arbitrary limit, used to avoid infinite loops when combined NoA
+        * descriptors cover the full time period.
+        */
+       int max_tries = 5;
+
+       ieee80211_extend_absent_time(data, tsf, &offset);
+       do {
+               if (!ieee80211_extend_absent_time(data, tsf, &offset))
+                       break;
+
+               tries++;
+       } while (tries < max_tries);
+
+       return offset;
+}
+
+void ieee80211_update_p2p_noa(struct ieee80211_noa_data *data, u32 tsf)
+{
+       u32 next_offset = BIT(31) - 1;
+       int i;
+
+       data->absent = 0;
+       data->has_next_tsf = false;
+       for (i = 0; i < IEEE80211_P2P_NOA_DESC_MAX; i++) {
+               s32 start;
+
+               if (!data->count[i])
+                       continue;
+
+               ieee80211_extend_noa_desc(data, tsf, i);
+               start = data->desc[i].start - tsf;
+               if (start <= 0)
+                       data->absent |= BIT(i);
+
+               if (next_offset > start)
+                       next_offset = start;
+
+               data->has_next_tsf = true;
+       }
+
+       if (data->absent)
+               next_offset = ieee80211_get_noa_absent_time(data, tsf);
+
+       data->next_tsf = tsf + next_offset;
+}
+EXPORT_SYMBOL(ieee80211_update_p2p_noa);
+
+int ieee80211_parse_p2p_noa(const struct ieee80211_p2p_noa_attr *attr,
+                           struct ieee80211_noa_data *data, u32 tsf)
+{
+       int ret = 0;
+       int i;
+
+       memset(data, 0, sizeof(*data));
+
+       for (i = 0; i < IEEE80211_P2P_NOA_DESC_MAX; i++) {
+               const struct ieee80211_p2p_noa_desc *desc = &attr->desc[i];
+
+               if (!desc->count || !desc->duration)
+                       continue;
+
+               data->count[i] = desc->count;
+               data->desc[i].start = le32_to_cpu(desc->start_time);
+               data->desc[i].duration = le32_to_cpu(desc->duration);
+               data->desc[i].interval = le32_to_cpu(desc->interval);
+
+               if (data->count[i] > 1 &&
+                   data->desc[i].interval < data->desc[i].duration)
+                       continue;
+
+               ieee80211_extend_noa_desc(data, tsf, i);
+               ret++;
+       }
+
+       if (ret)
+               ieee80211_update_p2p_noa(data, tsf);
+
+       return ret;
+}
+EXPORT_SYMBOL(ieee80211_parse_p2p_noa);