iwlwifi: mvm: detect U-APSD breaking aggregation

Try to detect that the AP is not using aggregation even when there's
enough traffic to make it worthwhile; if this is the case and U-APSD
is enabled then assume the AP is broken (like so many) and doesn't
enable aggregation when U-APSD is used. In this case, disconnect from
the AP and blacklist U-APSD for a potential new connection to it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/constants.h

@@ -69,6 +69,8 @@
 
 #include <linux/ieee80211.h>
 
+#define IWL_MVM_UAPSD_NOAGG_BSSIDS_NUM		20
+
 #define IWL_MVM_DEFAULT_PS_TX_DATA_TIMEOUT	(100 * USEC_PER_MSEC)
 #define IWL_MVM_DEFAULT_PS_RX_DATA_TIMEOUT	(100 * USEC_PER_MSEC)
 #define IWL_MVM_WOWLAN_PS_TX_DATA_TIMEOUT	(10 * USEC_PER_MSEC)
@@ -115,6 +117,8 @@
 #define IWL_MVM_TCM_LOAD_MEDIUM_THRESH		10 /* percentage */
 #define IWL_MVM_TCM_LOAD_HIGH_THRESH		50 /* percentage */
 #define IWL_MVM_TCM_LOWLAT_ENABLE_THRESH	100 /* packets/10 seconds */
+#define IWL_MVM_UAPSD_NONAGG_PERIOD		5000 /* msecs */
+#define IWL_MVM_UAPSD_NOAGG_LIST_LEN		IWL_MVM_UAPSD_NOAGG_BSSIDS_NUM
 #define IWL_MVM_RS_NUM_TRY_BEFORE_ANT_TOGGLE    1
 #define IWL_MVM_RS_HT_VHT_RETRIES_PER_RATE      2
 #define IWL_MVM_RS_HT_VHT_RETRIES_PER_RATE_TW   1

drivers/net/wireless/intel/iwlwifi/mvm/debugfs.c

@@ -1728,6 +1728,27 @@ iwl_dbgfs_send_echo_cmd_write(struct iwl_mvm *mvm, char *buf,
 	return ret ?: count;
 }
 
+static ssize_t
+iwl_dbgfs_uapsd_noagg_bssids_read(struct file *file, char __user *user_buf,
+				  size_t count, loff_t *ppos)
+{
+	struct iwl_mvm *mvm = file->private_data;
+	u8 buf[IWL_MVM_UAPSD_NOAGG_BSSIDS_NUM * ETH_ALEN * 3 + 1];
+	unsigned int pos = 0;
+	size_t bufsz = sizeof(buf);
+	int i;
+
+	mutex_lock(&mvm->mutex);
+
+	for (i = 0; i < IWL_MVM_UAPSD_NOAGG_LIST_LEN; i++)
+		pos += scnprintf(buf + pos, bufsz - pos, "%pM\n",
+				 mvm->uapsd_noagg_bssids[i].addr);
+
+	mutex_unlock(&mvm->mutex);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, pos);
+}
+
 MVM_DEBUGFS_READ_WRITE_FILE_OPS(prph_reg, 64);
 
 /* Device wide debugfs entries */
@@ -1762,6 +1783,8 @@ MVM_DEBUGFS_WRITE_FILE_OPS(indirection_tbl,
 			   (IWL_RSS_INDIRECTION_TABLE_SIZE * 2));
 MVM_DEBUGFS_WRITE_FILE_OPS(inject_packet, 512);
 
+MVM_DEBUGFS_READ_FILE_OPS(uapsd_noagg_bssids);
+
 #ifdef CONFIG_IWLWIFI_BCAST_FILTERING
 MVM_DEBUGFS_READ_WRITE_FILE_OPS(bcast_filters, 256);
 MVM_DEBUGFS_READ_WRITE_FILE_OPS(bcast_filters_macs, 256);
@@ -1972,6 +1995,8 @@ int iwl_mvm_dbgfs_register(struct iwl_mvm *mvm, struct dentry *dbgfs_dir)
 				 mvm->debugfs_dir, &mvm->drop_bcn_ap_mode))
 		goto err;
 
+	MVM_DEBUGFS_ADD_FILE(uapsd_noagg_bssids, mvm->debugfs_dir, S_IRUSR);
+
 #ifdef CONFIG_IWLWIFI_BCAST_FILTERING
 	if (mvm->fw->ucode_capa.flags & IWL_UCODE_TLV_FLAGS_BCAST_FILTERING) {
 		bcast_dir = debugfs_create_dir("bcast_filtering",

drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c

@@ -952,6 +952,16 @@ static int iwl_mvm_mac_ampdu_action(struct ieee80211_hw *hw,
 
 	switch (action) {
 	case IEEE80211_AMPDU_RX_START:
+		if (iwl_mvm_vif_from_mac80211(vif)->ap_sta_id ==
+				iwl_mvm_sta_from_mac80211(sta)->sta_id) {
+			struct iwl_mvm_vif *mvmvif;
+			u16 macid = iwl_mvm_vif_from_mac80211(vif)->id;
+			struct iwl_mvm_tcm_mac *mdata = &mvm->tcm.data[macid];
+
+			mdata->opened_rx_ba_sessions = true;
+			mvmvif = iwl_mvm_vif_from_mac80211(vif);
+			cancel_delayed_work(&mvmvif->uapsd_nonagg_detected_wk);
+		}
 		if (!iwl_enable_rx_ampdu(mvm->cfg)) {
 			ret = -EINVAL;
 			break;
@@ -1435,6 +1445,8 @@ static int iwl_mvm_mac_add_interface(struct ieee80211_hw *hw,
 		mvm->p2p_device_vif = vif;
 	}
 
+	iwl_mvm_tcm_add_vif(mvm, vif);
+
 	if (vif->type == NL80211_IFTYPE_MONITOR)
 		mvm->monitor_on = true;
 
@@ -1486,6 +1498,10 @@ static void iwl_mvm_mac_remove_interface(struct ieee80211_hw *hw,
 
 	iwl_mvm_prepare_mac_removal(mvm, vif);
 
+	if (!(vif->type == NL80211_IFTYPE_AP ||
+	      vif->type == NL80211_IFTYPE_ADHOC))
+		iwl_mvm_tcm_rm_vif(mvm, vif);
+
 	mutex_lock(&mvm->mutex);
 
 	if (mvm->bf_allowed_vif == mvmvif) {
@@ -2535,6 +2551,16 @@ static void iwl_mvm_sta_pre_rcu_remove(struct ieee80211_hw *hw,
 static void iwl_mvm_check_uapsd(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
 				const u8 *bssid)
 {
+	int i;
+
+	if (!test_bit(IWL_MVM_STATUS_IN_HW_RESTART, &mvm->status)) {
+		struct iwl_mvm_tcm_mac *mdata;
+
+		mdata = &mvm->tcm.data[iwl_mvm_vif_from_mac80211(vif)->id];
+		ewma_rate_init(&mdata->uapsd_nonagg_detect.rate);
+		mdata->opened_rx_ba_sessions = false;
+	}
+
 	if (!(mvm->fw->ucode_capa.flags & IWL_UCODE_TLV_FLAGS_UAPSD_SUPPORT))
 		return;
 
@@ -2549,6 +2575,13 @@ static void iwl_mvm_check_uapsd(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
 		return;
 	}
 
+	for (i = 0; i < IWL_MVM_UAPSD_NOAGG_LIST_LEN; i++) {
+		if (ether_addr_equal(mvm->uapsd_noagg_bssids[i].addr, bssid)) {
+			vif->driver_flags &= ~IEEE80211_VIF_SUPPORTS_UAPSD;
+			return;
+		}
+	}
+
 	vif->driver_flags |= IEEE80211_VIF_SUPPORTS_UAPSD;
 }
 

drivers/net/wireless/intel/iwlwifi/mvm/mvm.h

@@ -446,6 +446,8 @@ struct iwl_mvm_vif {
 	/* FW identified misbehaving AP */
 	u8 uapsd_misbehaving_bssid[ETH_ALEN];
 
+	struct delayed_work uapsd_nonagg_detected_wk;
+
 	/* Indicates that CSA countdown may be started */
 	bool csa_countdown;
 	bool csa_failed;
@@ -621,6 +623,7 @@ struct iwl_mvm_tcm_mac {
 		struct ewma_rate rate;
 		bool detected;
 	} uapsd_nonagg_detect;
+	bool opened_rx_ba_sessions;
 };
 
 struct iwl_mvm_tcm {
@@ -1028,6 +1031,10 @@ struct iwl_mvm {
 	unsigned long bt_coex_last_tcm_ts;
 	struct iwl_mvm_tcm tcm;
 
+	u8 uapsd_noagg_bssid_write_idx;
+	struct mac_address uapsd_noagg_bssids[IWL_MVM_UAPSD_NOAGG_BSSIDS_NUM]
+		__aligned(2);
+
 	struct iwl_time_quota_cmd last_quota_cmd;
 
 #ifdef CONFIG_NL80211_TESTMODE
@@ -1963,6 +1970,8 @@ void iwl_mvm_tcm_work(struct work_struct *work);
 void iwl_mvm_recalc_tcm(struct iwl_mvm *mvm);
 void iwl_mvm_pause_tcm(struct iwl_mvm *mvm, bool with_cancel);
 void iwl_mvm_resume_tcm(struct iwl_mvm *mvm);
+void iwl_mvm_tcm_add_vif(struct iwl_mvm *mvm, struct ieee80211_vif *vif);
+void iwl_mvm_tcm_rm_vif(struct iwl_mvm *mvm, struct ieee80211_vif *vif);
 u8 iwl_mvm_tcm_load_percentage(u32 airtime, u32 elapsed);
 
 void iwl_mvm_nic_restart(struct iwl_mvm *mvm, bool fw_error);

drivers/net/wireless/intel/iwlwifi/mvm/rx.c

@@ -264,6 +264,12 @@ static void iwl_mvm_rx_handle_tcm(struct iwl_mvm *mvm,
 	struct iwl_mvm_tcm_mac *mdata;
 	int mac;
 	int ac = IEEE80211_AC_BE; /* treat non-QoS as BE */
+	struct iwl_mvm_vif *mvmvif;
+	/* expected throughput in 100Kbps, single stream, 20 MHz */
+	static const u8 thresh_tpt[] = {
+		9, 18, 30, 42, 60, 78, 90, 96, 120, 135,
+	};
+	u16 thr;
 
 	if (ieee80211_is_data_qos(hdr->frame_control))
 		ac = tid_to_mac80211_ac[ieee80211_get_tid(hdr)];
@@ -285,6 +291,35 @@ static void iwl_mvm_rx_handle_tcm(struct iwl_mvm *mvm,
 	if (!(rate_n_flags & (RATE_MCS_HT_MSK | RATE_MCS_VHT_MSK)))
 		return;
 
+	mvmvif = iwl_mvm_vif_from_mac80211(mvmsta->vif);
+
+	if (mdata->opened_rx_ba_sessions ||
+	    mdata->uapsd_nonagg_detect.detected ||
+	    (!mvmvif->queue_params[IEEE80211_AC_VO].uapsd &&
+	     !mvmvif->queue_params[IEEE80211_AC_VI].uapsd &&
+	     !mvmvif->queue_params[IEEE80211_AC_BE].uapsd &&
+	     !mvmvif->queue_params[IEEE80211_AC_BK].uapsd) ||
+	    mvmsta->sta_id != mvmvif->ap_sta_id)
+		return;
+
+	if (rate_n_flags & RATE_MCS_HT_MSK) {
+		thr = thresh_tpt[rate_n_flags & RATE_HT_MCS_RATE_CODE_MSK];
+		thr *= 1 + ((rate_n_flags & RATE_HT_MCS_NSS_MSK) >>
+					RATE_HT_MCS_NSS_POS);
+	} else {
+		if (WARN_ON((rate_n_flags & RATE_VHT_MCS_RATE_CODE_MSK) >=
+				ARRAY_SIZE(thresh_tpt)))
+			return;
+		thr = thresh_tpt[rate_n_flags & RATE_VHT_MCS_RATE_CODE_MSK];
+		thr *= 1 + ((rate_n_flags & RATE_VHT_MCS_NSS_MSK) >>
+					RATE_VHT_MCS_NSS_POS);
+	}
+
+	thr <<= ((rate_n_flags & RATE_MCS_CHAN_WIDTH_MSK) >>
+				RATE_MCS_CHAN_WIDTH_POS);
+
+	mdata->uapsd_nonagg_detect.rx_bytes += len;
+	ewma_rate_add(&mdata->uapsd_nonagg_detect.rate, thr);
 }
 
 static void iwl_mvm_rx_csum(struct ieee80211_sta *sta,
@@ -693,6 +728,7 @@ void iwl_mvm_handle_rx_statistics(struct iwl_mvm *mvm,
 	int expected_size;
 	int i;
 	u8 *energy;
+	__le32 *bytes;
 	__le32 *air_time;
 	__le32 flags;
 
@@ -768,11 +804,13 @@ void iwl_mvm_handle_rx_statistics(struct iwl_mvm *mvm,
 		struct iwl_notif_statistics_v11 *v11 = (void *)&pkt->data;
 
 		energy = (void *)&v11->load_stats.avg_energy;
+		bytes = (void *)&v11->load_stats.byte_count;
 		air_time = (void *)&v11->load_stats.air_time;
 	} else {
 		struct iwl_notif_statistics_cdb *stats = (void *)&pkt->data;
 
 		energy = (void *)&stats->load_stats.avg_energy;
+		bytes = (void *)&stats->load_stats.byte_count;
 		air_time = (void *)&stats->load_stats.air_time;
 	}
 
@@ -802,6 +840,15 @@ void iwl_mvm_handle_rx_statistics(struct iwl_mvm *mvm,
 	for (i = 0; i < NUM_MAC_INDEX_DRIVER; i++) {
 		struct iwl_mvm_tcm_mac *mdata = &mvm->tcm.data[i];
 		u32 airtime = le32_to_cpu(air_time[i]);
+		u32 rx_bytes = le32_to_cpu(bytes[i]);
+
+		mdata->uapsd_nonagg_detect.rx_bytes += rx_bytes;
+		if (airtime) {
+			/* re-init every time to store rate from FW */
+			ewma_rate_init(&mdata->uapsd_nonagg_detect.rate);
+			ewma_rate_add(&mdata->uapsd_nonagg_detect.rate,
+				      rx_bytes * 8 / airtime);
+		}
 
 		mdata->rx.airtime += airtime;
 	}

drivers/net/wireless/intel/iwlwifi/mvm/utils.c

@@ -1503,12 +1503,109 @@ static void iwl_mvm_tcm_results(struct iwl_mvm *mvm)
 	mutex_unlock(&mvm->mutex);
 }
 
+static void iwl_mvm_tcm_uapsd_nonagg_detected_wk(struct work_struct *wk)
+{
+	struct iwl_mvm *mvm;
+	struct iwl_mvm_vif *mvmvif;
+	struct ieee80211_vif *vif;
+
+	mvmvif = container_of(wk, struct iwl_mvm_vif,
+			      uapsd_nonagg_detected_wk.work);
+	vif = container_of((void *)mvmvif, struct ieee80211_vif, drv_priv);
+	mvm = mvmvif->mvm;
+
+	if (mvm->tcm.data[mvmvif->id].opened_rx_ba_sessions)
+		return;
+
+	/* remember that this AP is broken */
+	memcpy(mvm->uapsd_noagg_bssids[mvm->uapsd_noagg_bssid_write_idx].addr,
+	       vif->bss_conf.bssid, ETH_ALEN);
+	mvm->uapsd_noagg_bssid_write_idx++;
+	if (mvm->uapsd_noagg_bssid_write_idx >= IWL_MVM_UAPSD_NOAGG_LIST_LEN)
+		mvm->uapsd_noagg_bssid_write_idx = 0;
+
+	iwl_mvm_connection_loss(mvm, vif,
+				"AP isn't using AMPDU with uAPSD enabled");
+}
+
+static void iwl_mvm_uapsd_agg_disconnect_iter(void *data, u8 *mac,
+					      struct ieee80211_vif *vif)
+{
+	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+	struct iwl_mvm *mvm = mvmvif->mvm;
+	int *mac_id = data;
+
+	if (vif->type != NL80211_IFTYPE_STATION)
+		return;
+
+	if (mvmvif->id != *mac_id)
+		return;
+
+	if (!vif->bss_conf.assoc)
+		return;
+
+	if (!mvmvif->queue_params[IEEE80211_AC_VO].uapsd &&
+	    !mvmvif->queue_params[IEEE80211_AC_VI].uapsd &&
+	    !mvmvif->queue_params[IEEE80211_AC_BE].uapsd &&
+	    !mvmvif->queue_params[IEEE80211_AC_BK].uapsd)
+		return;
+
+	if (mvm->tcm.data[*mac_id].uapsd_nonagg_detect.detected)
+		return;
+
+	mvm->tcm.data[*mac_id].uapsd_nonagg_detect.detected = true;
+	IWL_INFO(mvm,
+		 "detected AP should do aggregation but isn't, likely due to U-APSD\n");
+	schedule_delayed_work(&mvmvif->uapsd_nonagg_detected_wk, 15 * HZ);
+}
+
+static void iwl_mvm_check_uapsd_agg_expected_tpt(struct iwl_mvm *mvm,
+						 unsigned int elapsed,
+						 int mac)
+{
+	u64 bytes = mvm->tcm.data[mac].uapsd_nonagg_detect.rx_bytes;
+	u64 tpt;
+	unsigned long rate;
+
+	rate = ewma_rate_read(&mvm->tcm.data[mac].uapsd_nonagg_detect.rate);
+
+	if (!rate || mvm->tcm.data[mac].opened_rx_ba_sessions ||
+	    mvm->tcm.data[mac].uapsd_nonagg_detect.detected)
+		return;
+
+	if (iwl_mvm_has_new_rx_api(mvm)) {
+		tpt = 8 * bytes; /* kbps */
+		do_div(tpt, elapsed);
+		rate *= 1000; /* kbps */
+		if (tpt < 22 * rate / 100)
+			return;
+	} else {
+		/*
+		 * the rate here is actually the threshold, in 100Kbps units,
+		 * so do the needed conversion from bytes to 100Kbps:
+		 * 100kb = bits / (100 * 1000),
+		 * 100kbps = 100kb / (msecs / 1000) ==
+		 *           (bits / (100 * 1000)) / (msecs / 1000) ==
+		 *           bits / (100 * msecs)
+		 */
+		tpt = (8 * bytes);
+		do_div(tpt, elapsed * 100);
+		if (tpt < rate)
+			return;
+	}
+
+	ieee80211_iterate_active_interfaces_atomic(
+		mvm->hw, IEEE80211_IFACE_ITER_NORMAL,
+		iwl_mvm_uapsd_agg_disconnect_iter, &mac);
+}
 
 static unsigned long iwl_mvm_calc_tcm_stats(struct iwl_mvm *mvm,
 					    unsigned long ts,
 					    bool handle_uapsd)
 {
 	unsigned int elapsed = jiffies_to_msecs(ts - mvm->tcm.ts);
+	unsigned int uapsd_elapsed =
+		jiffies_to_msecs(ts - mvm->tcm.uapsd_nonagg_ts);
 	u32 total_airtime = 0;
 	int ac, mac;
 	bool low_latency = false;
@@ -1551,6 +1648,12 @@ static unsigned long iwl_mvm_calc_tcm_stats(struct iwl_mvm *mvm,
 		}
 		low_latency |= mvm->tcm.result.low_latency[mac];
 
+		if (!mvm->tcm.result.low_latency[mac] && handle_uapsd)
+			iwl_mvm_check_uapsd_agg_expected_tpt(mvm, uapsd_elapsed,
+							     mac);
+		/* clear old data */
+		if (handle_uapsd)
+			mdata->uapsd_nonagg_detect.rx_bytes = 0;
 		memset(&mdata->rx.airtime, 0, sizeof(mdata->rx.airtime));
 		memset(&mdata->tx.airtime, 0, sizeof(mdata->tx.airtime));
 	}
@@ -1592,7 +1695,8 @@ void iwl_mvm_recalc_tcm(struct iwl_mvm *mvm)
 {
 	unsigned long ts = jiffies;
 	bool handle_uapsd =
-		false;
+		time_after(ts, mvm->tcm.uapsd_nonagg_ts +
+			       msecs_to_jiffies(IWL_MVM_UAPSD_NONAGG_PERIOD));
 
 	spin_lock(&mvm->tcm.lock);
 	if (mvm->tcm.paused || !time_after(ts, mvm->tcm.ts + MVM_TCM_PERIOD)) {
@@ -1601,6 +1705,12 @@ void iwl_mvm_recalc_tcm(struct iwl_mvm *mvm)
 	}
 	spin_unlock(&mvm->tcm.lock);
 
+	if (handle_uapsd && iwl_mvm_has_new_rx_api(mvm)) {
+		mutex_lock(&mvm->mutex);
+		if (iwl_mvm_request_statistics(mvm, true))
+			handle_uapsd = false;
+		mutex_unlock(&mvm->mutex);
+	}
 
 	spin_lock(&mvm->tcm.lock);
 	/* re-check if somebody else won the recheck race */
@@ -1659,6 +1769,21 @@ void iwl_mvm_resume_tcm(struct iwl_mvm *mvm)
 	spin_unlock_bh(&mvm->tcm.lock);
 }
 
+void iwl_mvm_tcm_add_vif(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
+{
+	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+
+	INIT_DELAYED_WORK(&mvmvif->uapsd_nonagg_detected_wk,
+			  iwl_mvm_tcm_uapsd_nonagg_detected_wk);
+}
+
+void iwl_mvm_tcm_rm_vif(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
+{
+	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+
+	cancel_delayed_work_sync(&mvmvif->uapsd_nonagg_detected_wk);
+}
+
 
 void iwl_mvm_get_sync_time(struct iwl_mvm *mvm, u32 *gp2, u64 *boottime)
 {