mac80211: add helper for management / no-ack frame rate decision

All current rate control algorithms agree to send management and no-ack
frames at the lowest rate. They also agree to do this when sta
and the private rate control data is NULL. We add a hlper to mac80211
for this and simplify the rate control algorithm code.

Developers wishing to make enhancements to rate control algorithms
are for broadcast/multicast can opt to not use this in their
gate_rate() mac80211 callback.

Cc: Zhu Yi <yi.zhu@intel.com>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: ipw3945-devel@lists.sourceforge.net
Cc: Gabor Juhos <juhosg@openwrt.org>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Cc: Derek Smithies <derek@indranet.co.nz>
Cc: Chittajit Mitra <Chittajit.Mitra@Atheros.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c
index 4641f00a1e5c..8ac7a984d886 100644
--- a/net/mac80211/rate.c
+++ b/net/mac80211/rate.c
@@ -198,6 +198,35 @@ static void rate_control_release(struct kref *kref)
 	kfree(ctrl_ref);
 }
 
+static bool rc_no_data_or_no_ack(struct ieee80211_tx_rate_control *txrc)
+{
+	struct sk_buff *skb = txrc->skb;
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	__le16 fc;
+
+	fc = hdr->frame_control;
+
+	return ((info->flags & IEEE80211_TX_CTL_NO_ACK) || !ieee80211_is_data(fc));
+}
+
+bool rate_control_send_low(struct ieee80211_sta *sta,
+			   void *priv_sta,
+			   struct ieee80211_tx_rate_control *txrc)
+{
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
+
+	if (!sta || !priv_sta || rc_no_data_or_no_ack(txrc)) {
+		info->control.rates[0].idx = rate_lowest_index(txrc->sband, sta);
+		info->control.rates[0].count =
+			(info->flags & IEEE80211_TX_CTL_NO_ACK) ?
+			1 : txrc->hw->max_rate_tries;
+		return true;
+	}
+	return false;
+}
+EXPORT_SYMBOL(rate_control_send_low);
+
 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
 			   struct sta_info *sta,
 			   struct ieee80211_tx_rate_control *txrc)