Despite the 'RTS thr:off' setting a wireshark trace of IBSS
traffic with HT40 mode enabled between two ath9k cards revealed
some RTS/CTS traffic.
Debug and code analysis showed that most places setting
IEEE80211_TX_RC_USE_RTS_CTS respect the RTS strategy by
evaluating rts_threshold, e.g. net/mac80211/tx.c:
698 /* set up RTS protection if desired */
699 if (len > tx->local->hw.wiphy->rts_threshold) {
700 txrc.rts = true;
701 }
702
703 info->control.use_rts = txrc.rts;
or drivers/net/wireless/ath/ath9k/xmit.c
1238 /*
1239 * Handle RTS threshold for unaggregated HT frames.
1240 */
1241 if (bf_isampdu(bf) && !bf_isaggr(bf) &&
1242 (rates[i].flags & IEEE80211_TX_RC_MCS) &&
1243 unlikely(rts_thresh != (u32) -1)) {
1244 if (!rts_thresh || (len > rts_thresh))
1245 rts = true;
1246 }
The only place setting IEEE80211_TX_RC_USE_RTS_CTS unconditionally
was found in net/mac80211/rc80211_minstrel_ht.c.
Fix this by propagating the calculated use_rts value to the
minstrel_ht_set_rate() function and evaluate it accordingly
before setting IEEE80211_TX_RC_USE_RTS_CTS.
Signed-off-by: Peter Seiderer <ps.report@xxxxxxx>
---
net/mac80211/rc80211_minstrel_ht.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index 72b44d4c42d0..f52edef443fa 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -276,7 +276,8 @@ static const u8 minstrel_sample_seq[] = {
};
static void
-minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
+minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
+ bool use_rts);
/*
* Some VHT MCSes are invalid (when Ndbps / Nes is not an integer)
@@ -1254,7 +1255,7 @@ minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
}
if (update)
- minstrel_ht_update_rates(mp, mi);
+ minstrel_ht_update_rates(mp, mi, info->control.use_rts);
}
static void
@@ -1319,7 +1320,8 @@ minstrel_calc_retransmit(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
static void
minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
- struct ieee80211_sta_rates *ratetbl, int offset, int index)
+ struct ieee80211_sta_rates *ratetbl, int offset, int index,
+ bool use_rts)
{
int group_idx = MI_RATE_GROUP(index);
const struct mcs_group *group = &minstrel_mcs_groups[group_idx];
@@ -1357,7 +1359,7 @@ minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
* - if station is in dynamic SMPS (and streams > 1)
* - for fallback rates, to increase chances of getting through
*/
- if (offset > 0 ||
+ if ((offset > 0 && use_rts) ||
(mi->sta->smps_mode == IEEE80211_SMPS_DYNAMIC &&
group->streams > 1)) {
ratetbl->rate[offset].count = ratetbl->rate[offset].count_rts;
@@ -1426,7 +1428,8 @@ minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi)
}
static void
-minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
+minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
+ bool use_rts)
{
struct ieee80211_sta_rates *rates;
int i = 0;
@@ -1436,15 +1439,15 @@ minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
return;
/* Start with max_tp_rate[0] */
- minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
+ minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0], use_rts);
if (mp->hw->max_rates >= 3) {
/* At least 3 tx rates supported, use max_tp_rate[1] next */
- minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]);
+ minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1], use_rts);
}
if (mp->hw->max_rates >= 2) {
- minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
+ minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate, use_rts);
}
mi->sta->max_rc_amsdu_len = minstrel_ht_get_max_amsdu_len(mi);
@@ -1705,7 +1708,7 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
/* create an initial rate table with the lowest supported rates */
minstrel_ht_update_stats(mp, mi);
- minstrel_ht_update_rates(mp, mi);
+ minstrel_ht_update_rates(mp, mi, false);
}
static void
--
2.33.1
