[PATCH 2/4] wifi: mac80211: estimate expected throughput if not provided by driver/rc

[Felix Fietkau <nbd@nbd.name>]

Estimate the tx throughput based on the expected per-packet tx time.
This is useful for mesh implementations that rely on expected throughput,
e.g. 802.11s or batman-adv.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 net/mac80211/sta_info.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 4259e9c13ed7..912f00d905b8 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -2978,6 +2978,27 @@ static void sta_set_link_sinfo(struct sta_info *sta,
 	}
 }
 
+static u32 sta_estimate_expected_throughput(struct sta_info *sta,
+					    struct station_info *sinfo)
+{
+	struct ieee80211_sub_if_data *sdata = sta->sdata;
+	struct ieee80211_local *local = sdata->local;
+	struct rate_info *ri = &sinfo->txrate;
+	struct ieee80211_hw *hw = &local->hw;
+	struct ieee80211_chanctx_conf *conf;
+	u32 duration;
+	u8 band = 0;
+
+	conf = rcu_dereference(sdata->vif.bss_conf.chanctx_conf);
+	if (conf)
+			band = conf->def.chan->band;
+
+	duration = ieee80211_rate_expected_tx_airtime(hw, NULL, ri, band, true, 1024);
+	duration += duration >> 4; /* add assumed packet error rate of ~6% */
+
+	return ((1024 * USEC_PER_SEC) / duration) * 8;
+}
+
 void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo,
 		   bool tidstats)
 {
@@ -3202,6 +3223,8 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo,
 		sinfo->sta_flags.set |= BIT(NL80211_STA_FLAG_TDLS_PEER);
 
 	thr = sta_get_expected_throughput(sta);
+	if (!thr && (sinfo->filled & BIT_ULL(NL80211_STA_INFO_TX_BITRATE)))
+	    thr = sta_estimate_expected_throughput(sta, sinfo);
 
 	if (thr != 0) {
 		sinfo->filled |= BIT_ULL(NL80211_STA_INFO_EXPECTED_THROUGHPUT);
-- 
2.51.0