Default to the lowest negotiated rate for mgmt/multicast traffic in 11n mode

The current code transmits management and multicast frames at MCS 0.
What it should do is check whether the negotiated basic set is zero (and
the MCS set is not) before making this decision.

For now, simply default to the lowest negotiated rate, rather than
MCS 0. This fixes the behaviour with at least the DLINK DIR-825, which
ACKs but silently ignores block-ack (BA) response frames.

1 files changed, 18 insertions, 0 deletions

diff --git a/sys/net80211/ieee80211_proto.c b/sys/net80211/ieee80211_proto.c
index edac519..a0ddeb4 100644
--- a/sys/net80211/ieee80211_proto.c
+++ b/sys/net80211/ieee80211_proto.c
@@ -207,6 +207,21 @@ ieee80211_proto_vattach(struct ieee80211vap *vap)
 		const struct ieee80211_rateset *rs = &ic->ic_sup_rates[i];
 
 		vap->iv_txparms[i].ucastrate = IEEE80211_FIXED_RATE_NONE;
+
+		/*
+		 * Setting the management rate to MCS 0 assumes that the
+		 * BSS Basic rate set is empty and the BSS Basic MCS set
+		 * is not.
+		 *
+		 * Since we're not checking this, default to the lowest
+		 * defined rate for this mode.
+		 *
+		 * At least one 11n AP (DLINK DIR-825) is reported to drop
+		 * some MCS management traffic (eg BA response frames.)
+		 *
+		 * See also: 9.6.0 of the 802.11n-2009 specification.
+		 */
+#ifdef	NOTYET
 		if (i == IEEE80211_MODE_11NA || i == IEEE80211_MODE_11NG) {
 			vap->iv_txparms[i].mgmtrate = 0 | IEEE80211_RATE_MCS;
 			vap->iv_txparms[i].mcastrate = 0 | IEEE80211_RATE_MCS;
@@ -216,6 +231,9 @@ ieee80211_proto_vattach(struct ieee80211vap *vap)
 			vap->iv_txparms[i].mcastrate = 
 			    rs->rs_rates[0] & IEEE80211_RATE_VAL;
 		}
+#endif
+		vap->iv_txparms[i].mgmtrate = rs->rs_rates[0] & IEEE80211_RATE_VAL;
+		vap->iv_txparms[i].mcastrate = rs->rs_rates[0] & IEEE80211_RATE_VAL;
 		vap->iv_txparms[i].maxretry = IEEE80211_TXMAX_DEFAULT;
 	}
 	vap->iv_roaming = IEEE80211_ROAMING_AUTO;