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>
---
v3: avoid band=0 default, return 0 if no chanctx

 net/mac80211/sta_info.c | 49 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 46 insertions(+), 3 deletions(-)

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 4c86a3793804..b0a87d5a66ca 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -2769,6 +2769,28 @@ void sta_set_accumulated_removed_links_sinfo(struct sta_info *sta,
 	}
 }
 
+static u32 sta_estimate_expected_throughput(struct sta_info *sta,
+					    struct rate_info *ri,
+					    struct ieee80211_bss_conf *bss_conf)
+{
+	struct ieee80211_hw *hw = &sta->sdata->local->hw;
+	struct ieee80211_chanctx_conf *conf;
+	u32 duration;
+	u8 band;
+
+	conf = rcu_dereference(bss_conf->chanctx_conf);
+	if (!conf)
+		return 0;
+	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% */
+	if (!duration)
+		return 0;
+
+	return ((1024 * USEC_PER_SEC) / duration) * 8;
+}
+
 static void sta_set_link_sinfo(struct sta_info *sta,
 			       struct link_station_info *link_sinfo,
 			       struct ieee80211_link_data *link,
@@ -2983,6 +3005,10 @@ static void sta_set_link_sinfo(struct sta_info *sta,
 	link_sinfo->bss_param.beacon_interval = link->conf->beacon_int;
 
 	thr = sta_get_expected_throughput(sta);
+	if (!thr && (link_sinfo->filled & BIT_ULL(NL80211_STA_INFO_TX_BITRATE)))
+		thr = sta_estimate_expected_throughput(sta,
+						      &link_sinfo->txrate,
+						      link->conf);
 
 	if (thr != 0) {
 		link_sinfo->filled |=
@@ -3236,6 +3262,14 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo,
 	if (thr != 0) {
 		sinfo->filled |= BIT_ULL(NL80211_STA_INFO_EXPECTED_THROUGHPUT);
 		sinfo->expected_throughput = thr;
+	} else if (!sta->sta.valid_links &&
+		   (sinfo->filled & BIT_ULL(NL80211_STA_INFO_TX_BITRATE))) {
+		thr = sta_estimate_expected_throughput(sta, &sinfo->txrate,
+						      &sdata->vif.bss_conf);
+		if (thr) {
+			sinfo->filled |= BIT_ULL(NL80211_STA_INFO_EXPECTED_THROUGHPUT);
+			sinfo->expected_throughput = thr;
+		}
 	}
 
 	if (!(sinfo->filled & BIT_ULL(NL80211_STA_INFO_ACK_SIGNAL)) &&
@@ -3256,6 +3290,7 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo,
 	if (sta->sta.valid_links) {
 		struct ieee80211_link_data *link;
 		struct link_sta_info *link_sta;
+		u32 est_thr = 0;
 		int link_id;
 
 		sinfo->mlo_params_valid = true;
@@ -3267,17 +3302,25 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo,
 		sinfo->valid_links = sta->sta.valid_links;
 
 		for_each_valid_link(sinfo, link_id) {
+			struct link_station_info *lsi = sinfo->links[link_id];
+
 			link_sta = wiphy_dereference(sta->local->hw.wiphy,
 						     sta->link[link_id]);
 			link = wiphy_dereference(sdata->local->hw.wiphy,
 						 sdata->link[link_id]);
 
-			if (!link_sta || !sinfo->links[link_id] || !link) {
+			if (!link_sta || !lsi || !link) {
 				sinfo->valid_links &= ~BIT(link_id);
 				continue;
 			}
-			sta_set_link_sinfo(sta, sinfo->links[link_id],
-					   link, tidstats);
+			sta_set_link_sinfo(sta, lsi, link, tidstats);
+			if (!thr &&
+			    (lsi->filled & BIT_ULL(NL80211_STA_INFO_EXPECTED_THROUGHPUT)))
+				est_thr += lsi->expected_throughput;
+		}
+		if (est_thr) {
+			sinfo->filled |= BIT_ULL(NL80211_STA_INFO_EXPECTED_THROUGHPUT);
+			sinfo->expected_throughput = est_thr;
 		}
 	}
 }
-- 
2.53.0