mac80211: track receiver's aggregation reorder buffer size

The aggregation code currently doesn't implement the
buffer size negotiation. It will always request a max
buffer size (which is fine, if a little pointless, as
the mac80211 code doesn't know and might just use 0
instead), but if the peer requests a smaller size it
isn't possible to honour this request.

In order to fix this, look at the buffer size in the
addBA response frame, keep track of it and pass it to
the driver in the ampdu_action callback when called
with the IEEE80211_AMPDU_TX_OPERATIONAL action. That
way the driver can limit the number of subframes in
aggregates appropriately.

Note that this doesn't fix any drivers apart from the
addition of the new argument -- they all need to be
updated separately to use this variable!

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

17 files changed, 56 insertions, 24 deletions

diff --git a/drivers/net/wireless/ath/ar9170/main.c b/drivers/net/wireless/ath/ar9170/main.c
index 32bf79e6a320..a9111e1161fd 100644
--- a/drivers/net/wireless/ath/ar9170/main.c
+++ b/drivers/net/wireless/ath/ar9170/main.c
@@ -1945,7 +1945,8 @@ static int ar9170_conf_tx(struct ieee80211_hw *hw, u16 queue,
 static int ar9170_ampdu_action(struct ieee80211_hw *hw,
 			       struct ieee80211_vif *vif,
 			       enum ieee80211_ampdu_mlme_action action,
-			       struct ieee80211_sta *sta, u16 tid, u16 *ssn)
+			       struct ieee80211_sta *sta, u16 tid, u16 *ssn,
+			       u8 buf_size)
 {
 	switch (action) {
 	case IEEE80211_AMPDU_RX_START:
diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_main.c b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
index 187af5b4440d..f14f37d29f45 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_main.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
@@ -1549,7 +1549,7 @@ static int ath9k_htc_ampdu_action(struct ieee80211_hw *hw,
 				  struct ieee80211_vif *vif,
 				  enum ieee80211_ampdu_mlme_action action,
 				  struct ieee80211_sta *sta,
-				  u16 tid, u16 *ssn)
+				  u16 tid, u16 *ssn, u8 buf_size)
 {
 	struct ath9k_htc_priv *priv = hw->priv;
 	struct ath9k_htc_sta *ista;
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index 174c016ef89d..c03184e7bffe 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -2165,7 +2165,7 @@ static int ath9k_ampdu_action(struct ieee80211_hw *hw,
 			      struct ieee80211_vif *vif,
 			      enum ieee80211_ampdu_mlme_action action,
 			      struct ieee80211_sta *sta,
-			      u16 tid, u16 *ssn)
+			      u16 tid, u16 *ssn, u8 buf_size)
 {
 	struct ath_wiphy *aphy = hw->priv;
 	struct ath_softc *sc = aphy->sc;
diff --git a/drivers/net/wireless/ath/carl9170/main.c b/drivers/net/wireless/ath/carl9170/main.c
index 870df8c42622..ecfb80b059d1 100644
--- a/drivers/net/wireless/ath/carl9170/main.c
+++ b/drivers/net/wireless/ath/carl9170/main.c
@@ -1279,7 +1279,7 @@ static int carl9170_op_ampdu_action(struct ieee80211_hw *hw,
 				    struct ieee80211_vif *vif,
 				    enum ieee80211_ampdu_mlme_action action,
 				    struct ieee80211_sta *sta,
-				    u16 tid, u16 *ssn)
+				    u16 tid, u16 *ssn, u8 buf_size)
 {
 	struct ar9170 *ar = hw->priv;
 	struct carl9170_sta_info *sta_info = (void *) sta->drv_priv;
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 36335b1b54d4..8b045a401d62 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -3393,7 +3393,8 @@ int iwlagn_mac_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 int iwlagn_mac_ampdu_action(struct ieee80211_hw *hw,
 			    struct ieee80211_vif *vif,
 			    enum ieee80211_ampdu_mlme_action action,
-			    struct ieee80211_sta *sta, u16 tid, u16 *ssn)
+			    struct ieee80211_sta *sta, u16 tid, u16 *ssn,
+			    u8 buf_size)
 {
 	struct iwl_priv *priv = hw->priv;
 	int ret = -EINVAL;
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.h b/drivers/net/wireless/iwlwifi/iwl-agn.h
index da303585f801..822221a97e80 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.h
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.h
@@ -349,7 +349,8 @@ void iwlagn_mac_update_tkip_key(struct ieee80211_hw *hw,
 int iwlagn_mac_ampdu_action(struct ieee80211_hw *hw,
 			    struct ieee80211_vif *vif,
 			    enum ieee80211_ampdu_mlme_action action,
-			    struct ieee80211_sta *sta, u16 tid, u16 *ssn);
+			    struct ieee80211_sta *sta, u16 tid, u16 *ssn,
+			    u8 buf_size);
 int iwlagn_mac_sta_add(struct ieee80211_hw *hw,
 		       struct ieee80211_vif *vif,
 		       struct ieee80211_sta *sta);
diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 454f045ddff3..5d39b2840584 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -943,7 +943,8 @@ static int mac80211_hwsim_testmode_cmd(struct ieee80211_hw *hw,
 static int mac80211_hwsim_ampdu_action(struct ieee80211_hw *hw,
 				       struct ieee80211_vif *vif,
 				       enum ieee80211_ampdu_mlme_action action,
-				       struct ieee80211_sta *sta, u16 tid, u16 *ssn)
+				       struct ieee80211_sta *sta, u16 tid, u16 *ssn,
+				       u8 buf_size)
 {
 	switch (action) {
 	case IEEE80211_AMPDU_TX_START:
diff --git a/drivers/net/wireless/mwl8k.c b/drivers/net/wireless/mwl8k.c
index 809f2bf27958..106b427d0064 100644
--- a/drivers/net/wireless/mwl8k.c
+++ b/drivers/net/wireless/mwl8k.c
@@ -4356,7 +4356,8 @@ static int mwl8k_get_survey(struct ieee80211_hw *hw, int idx,
 static int
 mwl8k_ampdu_action(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 		   enum ieee80211_ampdu_mlme_action action,
-		   struct ieee80211_sta *sta, u16 tid, u16 *ssn)
+		   struct ieee80211_sta *sta, u16 tid, u16 *ssn,
+		   u8 buf_size)
 {
 	switch (action) {
 	case IEEE80211_AMPDU_RX_START:
diff --git a/drivers/net/wireless/rt2x00/rt2800lib.c b/drivers/net/wireless/rt2x00/rt2800lib.c
index a25be625ee90..f8ba01cbc6dd 100644
--- a/drivers/net/wireless/rt2x00/rt2800lib.c
+++ b/drivers/net/wireless/rt2x00/rt2800lib.c
@@ -3533,7 +3533,8 @@ EXPORT_SYMBOL_GPL(rt2800_get_tsf);
 
 int rt2800_ampdu_action(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 			enum ieee80211_ampdu_mlme_action action,
-			struct ieee80211_sta *sta, u16 tid, u16 *ssn)
+			struct ieee80211_sta *sta, u16 tid, u16 *ssn,
+			u8 buf_size)
 {
 	int ret = 0;
 
diff --git a/drivers/net/wireless/rt2x00/rt2800lib.h b/drivers/net/wireless/rt2x00/rt2800lib.h
index e3c995a9dec4..3efafb78ff77 100644
--- a/drivers/net/wireless/rt2x00/rt2800lib.h
+++ b/drivers/net/wireless/rt2x00/rt2800lib.h
@@ -198,7 +198,8 @@ int rt2800_conf_tx(struct ieee80211_hw *hw, u16 queue_idx,
 u64 rt2800_get_tsf(struct ieee80211_hw *hw);
 int rt2800_ampdu_action(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 			enum ieee80211_ampdu_mlme_action action,
-			struct ieee80211_sta *sta, u16 tid, u16 *ssn);
+			struct ieee80211_sta *sta, u16 tid, u16 *ssn,
+			u8 buf_size);
 int rt2800_get_survey(struct ieee80211_hw *hw, int idx,
 		      struct survey_info *survey);
 
diff --git a/drivers/net/wireless/rtlwifi/core.c b/drivers/net/wireless/rtlwifi/core.c
index d6a924a05654..25d2d667ffba 100644
--- a/drivers/net/wireless/rtlwifi/core.c
+++ b/drivers/net/wireless/rtlwifi/core.c
@@ -748,7 +748,8 @@ static void rtl_op_sta_notify(struct ieee80211_hw *hw,
 static int rtl_op_ampdu_action(struct ieee80211_hw *hw,
 			       struct ieee80211_vif *vif,
 			       enum ieee80211_ampdu_mlme_action action,
-			       struct ieee80211_sta *sta, u16 tid, u16 * ssn)
+			       struct ieee80211_sta *sta, u16 tid, u16 *ssn,
+			       u8 buf_size)
 {
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index d024fc563e7b..5afe341b4010 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1731,6 +1731,10 @@ enum ieee80211_ampdu_mlme_action {
  * 	ieee80211_ampdu_mlme_action. Starting sequence number (@ssn)
  * 	is the first frame we expect to perform the action on. Notice
  * 	that TX/RX_STOP can pass NULL for this parameter.
+ *	The @buf_size parameter is only valid when the action is set to
+ *	%IEEE80211_AMPDU_TX_OPERATIONAL and indicates the peer's reorder
+ *	buffer size (number of subframes) for this session -- aggregates
+ *	containing more subframes than this may not be transmitted to the peer.
  *	Returns a negative error code on failure.
  *	The callback can sleep.
  *
@@ -1833,7 +1837,8 @@ struct ieee80211_ops {
 	int (*ampdu_action)(struct ieee80211_hw *hw,
 			    struct ieee80211_vif *vif,
 			    enum ieee80211_ampdu_mlme_action action,
-			    struct ieee80211_sta *sta, u16 tid, u16 *ssn);
+			    struct ieee80211_sta *sta, u16 tid, u16 *ssn,
+			    u8 buf_size);
 	int (*get_survey)(struct ieee80211_hw *hw, int idx,
 		struct survey_info *survey);
 	void (*rfkill_poll)(struct ieee80211_hw *hw);
diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index 002db5e86eb6..1f51f4162426 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c
@@ -76,7 +76,7 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
 #endif /* CONFIG_MAC80211_HT_DEBUG */
 
 	if (drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_STOP,
-			     &sta->sta, tid, NULL))
+			     &sta->sta, tid, NULL, 0))
 		printk(KERN_DEBUG "HW problem - can not stop rx "
 				"aggregation for tid %d\n", tid);
 
@@ -297,7 +297,7 @@ void ieee80211_process_addba_request(struct ieee80211_local *local,
 	}
 
 	ret = drv_ampdu_action(local, sta->sdata, IEEE80211_AMPDU_RX_START,
-			       &sta->sta, tid, &start_seq_num);
+			       &sta->sta, tid, &start_seq_num, 0);
 #ifdef CONFIG_MAC80211_HT_DEBUG
 	printk(KERN_DEBUG "Rx A-MPDU request on tid %d result %d\n", tid, ret);
 #endif /* CONFIG_MAC80211_HT_DEBUG */
diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index 9cc472c6a6a5..42f7c9007331 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -190,7 +190,7 @@ int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 
 	ret = drv_ampdu_action(local, sta->sdata,
 			       IEEE80211_AMPDU_TX_STOP,
-			       &sta->sta, tid, NULL);
+			       &sta->sta, tid, NULL, 0);
 
 	/* HW shall not deny going back to legacy */
 	if (WARN_ON(ret)) {
@@ -311,7 +311,7 @@ void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 	start_seq_num = sta->tid_seq[tid] >> 4;
 
 	ret = drv_ampdu_action(local, sdata, IEEE80211_AMPDU_TX_START,
-			       &sta->sta, tid, &start_seq_num);
+			       &sta->sta, tid, &start_seq_num, 0);
 	if (ret) {
 #ifdef CONFIG_MAC80211_HT_DEBUG
 		printk(KERN_DEBUG "BA request denied - HW unavailable for"
@@ -487,7 +487,8 @@ static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
 
 	drv_ampdu_action(local, sta->sdata,
 			 IEEE80211_AMPDU_TX_OPERATIONAL,
-			 &sta->sta, tid, NULL);
+			 &sta->sta, tid, NULL,
+			 sta->ampdu_mlme.tid_tx[tid]->buf_size);
 
 	/*
 	 * synchronize with TX path, while splicing the TX path
@@ -742,9 +743,11 @@ void ieee80211_process_addba_resp(struct ieee80211_local *local,
 {
 	struct tid_ampdu_tx *tid_tx;
 	u16 capab, tid;
+	u8 buf_size;
 
 	capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
 	tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
+	buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 
 	mutex_lock(&sta->ampdu_mlme.mtx);
 
@@ -767,12 +770,23 @@ void ieee80211_process_addba_resp(struct ieee80211_local *local,
 
 	if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
 			== WLAN_STATUS_SUCCESS) {
+		/*
+		 * IEEE 802.11-2007 7.3.1.14:
+		 * In an ADDBA Response frame, when the Status Code field
+		 * is set to 0, the Buffer Size subfield is set to a value
+		 * of at least 1.
+		 */
+		if (!buf_size)
+			goto out;
+
 		if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
 				     &tid_tx->state)) {
 			/* ignore duplicate response */
 			goto out;
 		}
 
+		tid_tx->buf_size = buf_size;
+
 		if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
 			ieee80211_agg_tx_operational(local, sta, tid);
 
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 98d589960a49..78af32d4bc58 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -382,17 +382,17 @@ static inline int drv_ampdu_action(struct ieee80211_local *local,
 				   struct ieee80211_sub_if_data *sdata,
 				   enum ieee80211_ampdu_mlme_action action,
 				   struct ieee80211_sta *sta, u16 tid,
-				   u16 *ssn)
+				   u16 *ssn, u8 buf_size)
 {
 	int ret = -EOPNOTSUPP;
 
 	might_sleep();
 
-	trace_drv_ampdu_action(local, sdata, action, sta, tid, ssn);
+	trace_drv_ampdu_action(local, sdata, action, sta, tid, ssn, buf_size);
 
 	if (local->ops->ampdu_action)
 		ret = local->ops->ampdu_action(&local->hw, &sdata->vif, action,
-					       sta, tid, ssn);
+					       sta, tid, ssn, buf_size);
 
 	trace_drv_return_int(local, ret);
 
diff --git a/net/mac80211/driver-trace.h b/net/mac80211/driver-trace.h
index 49c84218b2f4..fbabbc2f181a 100644
--- a/net/mac80211/driver-trace.h
+++ b/net/mac80211/driver-trace.h
@@ -784,9 +784,9 @@ TRACE_EVENT(drv_ampdu_action,
 		 struct ieee80211_sub_if_data *sdata,
 		 enum ieee80211_ampdu_mlme_action action,
 		 struct ieee80211_sta *sta, u16 tid,
-		 u16 *ssn),
+		 u16 *ssn, u8 buf_size),
 
-	TP_ARGS(local, sdata, action, sta, tid, ssn),
+	TP_ARGS(local, sdata, action, sta, tid, ssn, buf_size),
 
 	TP_STRUCT__entry(
 		LOCAL_ENTRY
@@ -794,6 +794,7 @@ TRACE_EVENT(drv_ampdu_action,
 		__field(u32, action)
 		__field(u16, tid)
 		__field(u16, ssn)
+		__field(u8, buf_size)
 		VIF_ENTRY
 	),
 
@@ -804,11 +805,13 @@ TRACE_EVENT(drv_ampdu_action,
 		__entry->action = action;
 		__entry->tid = tid;
 		__entry->ssn = ssn ? *ssn : 0;
+		__entry->buf_size = buf_size;
 	),
 
 	TP_printk(
-		LOCAL_PR_FMT VIF_PR_FMT STA_PR_FMT " action:%d tid:%d",
-		LOCAL_PR_ARG, VIF_PR_ARG, STA_PR_ARG, __entry->action, __entry->tid
+		LOCAL_PR_FMT VIF_PR_FMT STA_PR_FMT " action:%d tid:%d buf:%d",
+		LOCAL_PR_ARG, VIF_PR_ARG, STA_PR_ARG, __entry->action,
+		__entry->tid, __entry->buf_size
 	)
 );
 
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index bbdd2a86a94b..ca0b69060ef7 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -82,6 +82,7 @@ enum ieee80211_sta_info_flags {
  * @state: session state (see above)
  * @stop_initiator: initiator of a session stop
  * @tx_stop: TX DelBA frame when stopping
+ * @buf_size: reorder buffer size at receiver
  *
  * This structure's lifetime is managed by RCU, assignments to
  * the array holding it must hold the aggregation mutex.
@@ -101,6 +102,7 @@ struct tid_ampdu_tx {
 	u8 dialog_token;
 	u8 stop_initiator;
 	bool tx_stop;
+	u8 buf_size;
 };
 
 /**