mac80211: handle protection mode, RIFS and ADDBA for HT IBSS

* Follow 802.11n-2009 9.13.3.1 for protection mode and ADDBA
* Send ADDBA only to HT STAs - implement 11.5.1.1 partially

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index 2c2e9519a2e7..9bfe28c9ab59 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -430,6 +430,27 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
                 return -EINVAL;
         }
 
+        /*
+         * 802.11n-2009 11.5.1.1: If the initiating STA is an HT STA, is a
+         * member of an IBSS, and has no other existing Block Ack agreement
+         * with the recipient STA, then the initiating STA shall transmit a
+         * Probe Request frame to the recipient STA and shall not transmit an
+         * ADDBA Request frame unless it receives a Probe Response frame
+         * from the recipient within dot11ADDBAFailureTimeout.
+         *
+         * The probe request mechanism for ADDBA is currently not implemented,
+         * but we only build up Block Ack session with HT STAs. This information
+         * is set when we receive a bss info from a probe response or a beacon.
+         */
+        if (sta->sdata->vif.type == NL80211_IFTYPE_ADHOC &&
+            !sta->sta.ht_cap.ht_supported) {
+#ifdef CONFIG_MAC80211_HT_DEBUG
+                printk(KERN_DEBUG "BA request denied - IBSS STA %pM"
+                       "does not advertise HT support\n", pubsta->addr);
+#endif /* CONFIG_MAC80211_HT_DEBUG */
+                return -EINVAL;
+        }
+
         spin_lock_bh(&sta->lock);
 
         /* we have tried too many times, receiver does not want A-MPDU */