net/mac80211/status.c - kernel/msm-4.19 - Gitiles

 /*
  * Copyright 2002-2005, Instant802 Networks, Inc.
  * Copyright 2005-2006, Devicescape Software, Inc.
  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
  * Copyright 2008-2010	Johannes Berg <johannes@sipsolutions.net>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <net/mac80211.h>
 #include "ieee80211_i.h"
 #include "rate.h"
 #include "mesh.h"
 #include "led.h"


 void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw,
 				 struct sk_buff *skb)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	int tmp;

 	skb->pkt_type = IEEE80211_TX_STATUS_MSG;
 	skb_queue_tail(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS ?
 		       &local->skb_queue : &local->skb_queue_unreliable, skb);
 	tmp = skb_queue_len(&local->skb_queue) +
 		skb_queue_len(&local->skb_queue_unreliable);
 	while (tmp > IEEE80211_IRQSAFE_QUEUE_LIMIT &&
 	       (skb = skb_dequeue(&local->skb_queue_unreliable))) {
 		dev_kfree_skb_irq(skb);
 		tmp--;
 		I802_DEBUG_INC(local->tx_status_drop);
 	}
 	tasklet_schedule(&local->tasklet);
 }
 EXPORT_SYMBOL(ieee80211_tx_status_irqsafe);

 static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
 					    struct sta_info *sta,
 					    struct sk_buff *skb)
 {
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);

 	/*
 	 * This skb 'survived' a round-trip through the driver, and
 	 * hopefully the driver didn't mangle it too badly. However,
 	 * we can definitely not rely on the control information
 	 * being correct. Clear it so we don't get junk there, and
 	 * indicate that it needs new processing, but must not be
 	 * modified/encrypted again.
 	 */
 	memset(&info->control, 0, sizeof(info->control));

 	info->control.jiffies = jiffies;
 	info->control.vif = &sta->sdata->vif;
 	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING |
 		       IEEE80211_TX_INTFL_RETRANSMISSION;
 	info->flags &= ~IEEE80211_TX_TEMPORARY_FLAGS;

 	sta->tx_filtered_count++;

 	/*
 	 * Clear the TX filter mask for this STA when sending the next
 	 * packet. If the STA went to power save mode, this will happen
 	 * when it wakes up for the next time.
 	 */
 	set_sta_flags(sta, WLAN_STA_CLEAR_PS_FILT);

 	/*
 	 * This code races in the following way:
 	 *
 	 *  (1) STA sends frame indicating it will go to sleep and does so
 	 *  (2) hardware/firmware adds STA to filter list, passes frame up
 	 *  (3) hardware/firmware processes TX fifo and suppresses a frame
 	 *  (4) we get TX status before having processed the frame and
 	 *	knowing that the STA has gone to sleep.
 	 *
 	 * This is actually quite unlikely even when both those events are
 	 * processed from interrupts coming in quickly after one another or
 	 * even at the same time because we queue both TX status events and
 	 * RX frames to be processed by a tasklet and process them in the
 	 * same order that they were received or TX status last. Hence, there
 	 * is no race as long as the frame RX is processed before the next TX
 	 * status, which drivers can ensure, see below.
 	 *
 	 * Note that this can only happen if the hardware or firmware can
 	 * actually add STAs to the filter list, if this is done by the
 	 * driver in response to set_tim() (which will only reduce the race
 	 * this whole filtering tries to solve, not completely solve it)
 	 * this situation cannot happen.
 	 *
 	 * To completely solve this race drivers need to make sure that they
 	 *  (a) don't mix the irq-safe/not irq-safe TX status/RX processing
 	 *	functions and
 	 *  (b) always process RX events before TX status events if ordering
 	 *      can be unknown, for example with different interrupt status
 	 *	bits.
 	 *  (c) if PS mode transitions are manual (i.e. the flag
 	 *      %IEEE80211_HW_AP_LINK_PS is set), always process PS state
 	 *      changes before calling TX status events if ordering can be
 	 *	unknown.
 	 */
 	if (test_sta_flags(sta, WLAN_STA_PS_STA) &&
 	    skb_queue_len(&sta->tx_filtered) < STA_MAX_TX_BUFFER) {
 		skb_queue_tail(&sta->tx_filtered, skb);
 		sta_info_recalc_tim(sta);

 		if (!timer_pending(&local->sta_cleanup))
 			mod_timer(&local->sta_cleanup,
 				  round_jiffies(jiffies +
 						STA_INFO_CLEANUP_INTERVAL));
 		return;
 	}

 	if (!test_sta_flags(sta, WLAN_STA_PS_STA) &&
 	    !(info->flags & IEEE80211_TX_INTFL_RETRIED)) {
 		/* Software retry the packet once */
 		info->flags |= IEEE80211_TX_INTFL_RETRIED;
 		ieee80211_add_pending_skb(local, skb);
 		return;
 	}

 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 	if (net_ratelimit())
 		wiphy_debug(local->hw.wiphy,
 			    "dropped TX filtered frame, queue_len=%d PS=%d @%lu\n",
 			    skb_queue_len(&sta->tx_filtered),
 			    !!test_sta_flags(sta, WLAN_STA_PS_STA), jiffies);
 #endif
 	dev_kfree_skb(skb);
 }

 static void ieee80211_check_pending_bar(struct sta_info *sta, u8 *addr, u8 tid)
 {
 	struct tid_ampdu_tx *tid_tx;

 	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 	if (!tid_tx || !tid_tx->bar_pending)
 		return;

 	tid_tx->bar_pending = false;
 	ieee80211_send_bar(&sta->sdata->vif, addr, tid, tid_tx->failed_bar_ssn);
 }

 static void ieee80211_frame_acked(struct sta_info *sta, struct sk_buff *skb)
 {
 	struct ieee80211_mgmt *mgmt = (void *) skb->data;
 	struct ieee80211_local *local = sta->local;
 	struct ieee80211_sub_if_data *sdata = sta->sdata;

 	if (ieee80211_is_data_qos(mgmt->frame_control)) {
 		struct ieee80211_hdr *hdr = (void *) skb->data;
 		u8 *qc = ieee80211_get_qos_ctl(hdr);
 		u16 tid = qc[0] & 0xf;

 		ieee80211_check_pending_bar(sta, hdr->addr1, tid);
 	}

 	if (ieee80211_is_action(mgmt->frame_control) &&
 	    sdata->vif.type == NL80211_IFTYPE_STATION &&
 	    mgmt->u.action.category == WLAN_CATEGORY_HT &&
 	    mgmt->u.action.u.ht_smps.action == WLAN_HT_ACTION_SMPS) {
 		/*
 		 * This update looks racy, but isn't -- if we come
 		 * here we've definitely got a station that we're
 		 * talking to, and on a managed interface that can
 		 * only be the AP. And the only other place updating
 		 * this variable is before we're associated.
 		 */
 		switch (mgmt->u.action.u.ht_smps.smps_control) {
 		case WLAN_HT_SMPS_CONTROL_DYNAMIC:
 			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_DYNAMIC;
 			break;
 		case WLAN_HT_SMPS_CONTROL_STATIC:
 			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_STATIC;
 			break;
 		case WLAN_HT_SMPS_CONTROL_DISABLED:
 		default: /* shouldn't happen since we don't send that */
 			sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_OFF;
 			break;
 		}

 		ieee80211_queue_work(&local->hw, &local->recalc_smps);
 	}
 }

 static void ieee80211_set_bar_pending(struct sta_info *sta, u8 tid, u16 ssn)
 {
 	struct tid_ampdu_tx *tid_tx;

 	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 	if (!tid_tx)
 		return;

 	tid_tx->failed_bar_ssn = ssn;
 	tid_tx->bar_pending = true;
 }

 /*
  * Use a static threshold for now, best value to be determined
  * by testing ...
  * Should it depend on:
  *  - on # of retransmissions
  *  - current throughput (higher value for higher tpt)?
  */
 #define STA_LOST_PKT_THRESHOLD	50

 void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct sk_buff *skb2;
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 	struct ieee80211_local *local = hw_to_local(hw);
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	u16 frag, type;
 	__le16 fc;
 	struct ieee80211_supported_band *sband;
 	struct ieee80211_tx_status_rtap_hdr *rthdr;
 	struct ieee80211_sub_if_data *sdata;
 	struct net_device *prev_dev = NULL;
 	struct sta_info *sta, *tmp;
 	int retry_count = -1, i;
 	int rates_idx = -1;
 	bool send_to_cooked;
 	bool acked;
 	struct ieee80211_bar *bar;
 	u16 tid;

 	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
 		if (info->status.rates[i].idx < 0) {
 			break;
 		} else if (i >= hw->max_report_rates) {
 			/* the HW cannot have attempted that rate */
 			info->status.rates[i].idx = -1;
 			info->status.rates[i].count = 0;
 			break;
 		}

 		retry_count += info->status.rates[i].count;
 	}
 	rates_idx = i - 1;

 	if (retry_count < 0)
 		retry_count = 0;

 	rcu_read_lock();

 	sband = local->hw.wiphy->bands[info->band];
 	fc = hdr->frame_control;

 	for_each_sta_info(local, hdr->addr1, sta, tmp) {
 		/* skip wrong virtual interface */
 		if (memcmp(hdr->addr2, sta->sdata->vif.addr, ETH_ALEN))
 			continue;

 		acked = !!(info->flags & IEEE80211_TX_STAT_ACK);
 		if (!acked && test_sta_flags(sta, WLAN_STA_PS_STA)) {
 			/*
 			 * The STA is in power save mode, so assume
 			 * that this TX packet failed because of that.
 			 */
 			ieee80211_handle_filtered_frame(local, sta, skb);
 			rcu_read_unlock();
 			return;
 		}

 		if ((local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) &&
 		    (rates_idx != -1))
 			sta->last_tx_rate = info->status.rates[rates_idx];

 		if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
 		    (ieee80211_is_data_qos(fc))) {
 			u16 tid, ssn;
 			u8 *qc;

 			qc = ieee80211_get_qos_ctl(hdr);
 			tid = qc[0] & 0xf;
 			ssn = ((le16_to_cpu(hdr->seq_ctrl) + 0x10)
 						& IEEE80211_SCTL_SEQ);
 			ieee80211_send_bar(&sta->sdata->vif, hdr->addr1,
 					   tid, ssn);
 		}

 		if (!acked && ieee80211_is_back_req(fc)) {
 			u16 control;

 			/*
 			 * BAR failed, store the last SSN and retry sending
 			 * the BAR when the next unicast transmission on the
 			 * same TID succeeds.
 			 */
 			bar = (struct ieee80211_bar *) skb->data;
 			control = le16_to_cpu(bar->control);
 			if (!(control & IEEE80211_BAR_CTRL_MULTI_TID)) {
 				u16 ssn = le16_to_cpu(bar->start_seq_num);

 				tid = (control &
 				       IEEE80211_BAR_CTRL_TID_INFO_MASK) >>
 				      IEEE80211_BAR_CTRL_TID_INFO_SHIFT;

 				ieee80211_set_bar_pending(sta, tid, ssn);
 			}
 		}

 		if (info->flags & IEEE80211_TX_STAT_TX_FILTERED) {
 			ieee80211_handle_filtered_frame(local, sta, skb);
 			rcu_read_unlock();
 			return;
 		} else {
 			if (!acked)
 				sta->tx_retry_failed++;
 			sta->tx_retry_count += retry_count;
 		}

 		rate_control_tx_status(local, sband, sta, skb);
 		if (ieee80211_vif_is_mesh(&sta->sdata->vif))
 			ieee80211s_update_metric(local, sta, skb);

 		if (!(info->flags & IEEE80211_TX_CTL_INJECTED) && acked)
 			ieee80211_frame_acked(sta, skb);

 		if ((sta->sdata->vif.type == NL80211_IFTYPE_STATION) &&
 		    (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS))
 			ieee80211_sta_tx_notify(sta->sdata, (void *) skb->data, acked);

 		if (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) {
 			if (info->flags & IEEE80211_TX_STAT_ACK) {
 				if (sta->lost_packets)
 					sta->lost_packets = 0;
 			} else if (++sta->lost_packets >= STA_LOST_PKT_THRESHOLD) {
 				cfg80211_cqm_pktloss_notify(sta->sdata->dev,
 							    sta->sta.addr,
 							    sta->lost_packets,
 							    GFP_ATOMIC);
 				sta->lost_packets = 0;
 			}
 		}
 	}

 	rcu_read_unlock();

 	ieee80211_led_tx(local, 0);

 	/* SNMP counters
 	 * Fragments are passed to low-level drivers as separate skbs, so these
 	 * are actually fragments, not frames. Update frame counters only for
 	 * the first fragment of the frame. */

 	frag = le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG;
 	type = le16_to_cpu(hdr->frame_control) & IEEE80211_FCTL_FTYPE;

 	if (info->flags & IEEE80211_TX_STAT_ACK) {
 		if (frag == 0) {
 			local->dot11TransmittedFrameCount++;
 			if (is_multicast_ether_addr(hdr->addr1))
 				local->dot11MulticastTransmittedFrameCount++;
 			if (retry_count > 0)
 				local->dot11RetryCount++;
 			if (retry_count > 1)
 				local->dot11MultipleRetryCount++;
 		}

 		/* This counter shall be incremented for an acknowledged MPDU
 		 * with an individual address in the address 1 field or an MPDU
 		 * with a multicast address in the address 1 field of type Data
 		 * or Management. */
 		if (!is_multicast_ether_addr(hdr->addr1) ||
 		    type == IEEE80211_FTYPE_DATA ||
 		    type == IEEE80211_FTYPE_MGMT)
 			local->dot11TransmittedFragmentCount++;
 	} else {
 		if (frag == 0)
 			local->dot11FailedCount++;
 	}

 	if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc) &&
 	    (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) &&
 	    !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
 	    local->ps_sdata && !(local->scanning)) {
 		if (info->flags & IEEE80211_TX_STAT_ACK) {
 			local->ps_sdata->u.mgd.flags |=
 					IEEE80211_STA_NULLFUNC_ACKED;
 		} else
 			mod_timer(&local->dynamic_ps_timer, jiffies +
 					msecs_to_jiffies(10));
 	}

 	if (info->flags & IEEE80211_TX_INTFL_NL80211_FRAME_TX) {
 		struct ieee80211_work *wk;
 		u64 cookie = (unsigned long)skb;

 		rcu_read_lock();
 		list_for_each_entry_rcu(wk, &local->work_list, list) {
 			if (wk->type != IEEE80211_WORK_OFFCHANNEL_TX)
 				continue;
 			if (wk->offchan_tx.frame != skb)
 				continue;
 			wk->offchan_tx.frame = NULL;
 			break;
 		}
 		rcu_read_unlock();
 		if (local->hw_roc_skb_for_status == skb) {
 			cookie = local->hw_roc_cookie ^ 2;
 			local->hw_roc_skb_for_status = NULL;
 		}

 		cfg80211_mgmt_tx_status(
 			skb->dev, cookie, skb->data, skb->len,
 			!!(info->flags & IEEE80211_TX_STAT_ACK), GFP_ATOMIC);
 	}

 	/* this was a transmitted frame, but now we want to reuse it */
 	skb_orphan(skb);

 	/* Need to make a copy before skb->cb gets cleared */
 	send_to_cooked = !!(info->flags & IEEE80211_TX_CTL_INJECTED) ||
 			(type != IEEE80211_FTYPE_DATA);

 	/*
 	 * This is a bit racy but we can avoid a lot of work
 	 * with this test...
 	 */
 	if (!local->monitors && (!send_to_cooked || !local->cooked_mntrs)) {
 		dev_kfree_skb(skb);
 		return;
 	}

 	/* send frame to monitor interfaces now */

 	if (skb_headroom(skb) < sizeof(*rthdr)) {
 		printk(KERN_ERR "ieee80211_tx_status: headroom too small\n");
 		dev_kfree_skb(skb);
 		return;
 	}

 	rthdr = (struct ieee80211_tx_status_rtap_hdr *)
 				skb_push(skb, sizeof(*rthdr));

 	memset(rthdr, 0, sizeof(*rthdr));
 	rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
 	rthdr->hdr.it_present =
 		cpu_to_le32((1 << IEEE80211_RADIOTAP_TX_FLAGS) |
 			    (1 << IEEE80211_RADIOTAP_DATA_RETRIES) |
 			    (1 << IEEE80211_RADIOTAP_RATE));

 	if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
 	    !is_multicast_ether_addr(hdr->addr1))
 		rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_FAIL);

 	/*
 	 * XXX: Once radiotap gets the bitmap reset thing the vendor
 	 *	extensions proposal contains, we can actually report
 	 *	the whole set of tries we did.
 	 */
 	if ((info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS) ||
 	    (info->status.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT))
 		rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_CTS);
 	else if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
 		rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_RTS);
 	if (info->status.rates[0].idx >= 0 &&
 	    !(info->status.rates[0].flags & IEEE80211_TX_RC_MCS))
 		rthdr->rate = sband->bitrates[
 				info->status.rates[0].idx].bitrate / 5;

 	/* for now report the total retry_count */
 	rthdr->data_retries = retry_count;

 	/* XXX: is this sufficient for BPF? */
 	skb_set_mac_header(skb, 0);
 	skb->ip_summed = CHECKSUM_UNNECESSARY;
 	skb->pkt_type = PACKET_OTHERHOST;
 	skb->protocol = htons(ETH_P_802_2);
 	memset(skb->cb, 0, sizeof(skb->cb));

 	rcu_read_lock();
 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 		if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
 			if (!ieee80211_sdata_running(sdata))
 				continue;

 			if ((sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) &&
 			    !send_to_cooked)
 				continue;

 			if (prev_dev) {
 				skb2 = skb_clone(skb, GFP_ATOMIC);
 				if (skb2) {
 					skb2->dev = prev_dev;
 					netif_rx(skb2);
 				}
 			}

 			prev_dev = sdata->dev;
 		}
 	}
 	if (prev_dev) {
 		skb->dev = prev_dev;
 		netif_rx(skb);
 		skb = NULL;
 	}
 	rcu_read_unlock();
 	dev_kfree_skb(skb);
 }
 EXPORT_SYMBOL(ieee80211_tx_status);

 void ieee80211_report_low_ack(struct ieee80211_sta *pubsta, u32 num_packets)
 {
 	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
 	cfg80211_cqm_pktloss_notify(sta->sdata->dev, sta->sta.addr,
 				    num_packets, GFP_ATOMIC);
 }
 EXPORT_SYMBOL(ieee80211_report_low_ack);
	/*
	* Copyright 2002-2005, Instant802 Networks, Inc.
	* Copyright 2005-2006, Devicescape Software, Inc.
	* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
	* Copyright 2008-2010 Johannes Berg <johannes@sipsolutions.net>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <net/mac80211.h>
	#include "ieee80211_i.h"
	#include "rate.h"
	#include "mesh.h"
	#include "led.h"


	void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw,
	struct sk_buff *skb)
	{
	struct ieee80211_local *local = hw_to_local(hw);
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	int tmp;

	skb->pkt_type = IEEE80211_TX_STATUS_MSG;
	skb_queue_tail(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS ?
	&local->skb_queue : &local->skb_queue_unreliable, skb);
	tmp = skb_queue_len(&local->skb_queue) +
	skb_queue_len(&local->skb_queue_unreliable);
	while (tmp > IEEE80211_IRQSAFE_QUEUE_LIMIT &&
	(skb = skb_dequeue(&local->skb_queue_unreliable))) {
	dev_kfree_skb_irq(skb);
	tmp--;
	I802_DEBUG_INC(local->tx_status_drop);
	}
	tasklet_schedule(&local->tasklet);
	}
	EXPORT_SYMBOL(ieee80211_tx_status_irqsafe);

	static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
	struct sta_info *sta,
	struct sk_buff *skb)
	{
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);

	/*
	* This skb 'survived' a round-trip through the driver, and
	* hopefully the driver didn't mangle it too badly. However,
	* we can definitely not rely on the control information
	* being correct. Clear it so we don't get junk there, and
	* indicate that it needs new processing, but must not be
	* modified/encrypted again.
	*/
	memset(&info->control, 0, sizeof(info->control));

	info->control.jiffies = jiffies;
	info->control.vif = &sta->sdata->vif;
	info->flags \|= IEEE80211_TX_INTFL_NEED_TXPROCESSING \|
	IEEE80211_TX_INTFL_RETRANSMISSION;
	info->flags &= ~IEEE80211_TX_TEMPORARY_FLAGS;

	sta->tx_filtered_count++;

	/*
	* Clear the TX filter mask for this STA when sending the next
	* packet. If the STA went to power save mode, this will happen
	* when it wakes up for the next time.
	*/
	set_sta_flags(sta, WLAN_STA_CLEAR_PS_FILT);

	/*
	* This code races in the following way:
	*
	* (1) STA sends frame indicating it will go to sleep and does so
	* (2) hardware/firmware adds STA to filter list, passes frame up
	* (3) hardware/firmware processes TX fifo and suppresses a frame
	* (4) we get TX status before having processed the frame and
	* knowing that the STA has gone to sleep.
	*
	* This is actually quite unlikely even when both those events are
	* processed from interrupts coming in quickly after one another or
	* even at the same time because we queue both TX status events and
	* RX frames to be processed by a tasklet and process them in the
	* same order that they were received or TX status last. Hence, there
	* is no race as long as the frame RX is processed before the next TX
	* status, which drivers can ensure, see below.
	*
	* Note that this can only happen if the hardware or firmware can
	* actually add STAs to the filter list, if this is done by the
	* driver in response to set_tim() (which will only reduce the race
	* this whole filtering tries to solve, not completely solve it)
	* this situation cannot happen.
	*
	* To completely solve this race drivers need to make sure that they
	* (a) don't mix the irq-safe/not irq-safe TX status/RX processing
	* functions and
	* (b) always process RX events before TX status events if ordering
	* can be unknown, for example with different interrupt status
	* bits.
	* (c) if PS mode transitions are manual (i.e. the flag
	* %IEEE80211_HW_AP_LINK_PS is set), always process PS state
	* changes before calling TX status events if ordering can be
	* unknown.
	*/
	if (test_sta_flags(sta, WLAN_STA_PS_STA) &&
	skb_queue_len(&sta->tx_filtered) < STA_MAX_TX_BUFFER) {
	skb_queue_tail(&sta->tx_filtered, skb);
	sta_info_recalc_tim(sta);

	if (!timer_pending(&local->sta_cleanup))
	mod_timer(&local->sta_cleanup,
	round_jiffies(jiffies +
	STA_INFO_CLEANUP_INTERVAL));
	return;
	}

	if (!test_sta_flags(sta, WLAN_STA_PS_STA) &&
	!(info->flags & IEEE80211_TX_INTFL_RETRIED)) {
	/* Software retry the packet once */
	info->flags \|= IEEE80211_TX_INTFL_RETRIED;
	ieee80211_add_pending_skb(local, skb);
	return;
	}

	#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
	if (net_ratelimit())
	wiphy_debug(local->hw.wiphy,
	"dropped TX filtered frame, queue_len=%d PS=%d @%lu\n",
	skb_queue_len(&sta->tx_filtered),
	!!test_sta_flags(sta, WLAN_STA_PS_STA), jiffies);
	#endif
	dev_kfree_skb(skb);
	}

	static void ieee80211_check_pending_bar(struct sta_info sta, u8 addr, u8 tid)
	{
	struct tid_ampdu_tx *tid_tx;

	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
	if (!tid_tx \|\| !tid_tx->bar_pending)
	return;

	tid_tx->bar_pending = false;
	ieee80211_send_bar(&sta->sdata->vif, addr, tid, tid_tx->failed_bar_ssn);
	}

	static void ieee80211_frame_acked(struct sta_info sta, struct sk_buff skb)
	{
	struct ieee80211_mgmt mgmt = (void ) skb->data;
	struct ieee80211_local *local = sta->local;
	struct ieee80211_sub_if_data *sdata = sta->sdata;

	if (ieee80211_is_data_qos(mgmt->frame_control)) {
	struct ieee80211_hdr hdr = (void ) skb->data;
	u8 *qc = ieee80211_get_qos_ctl(hdr);
	u16 tid = qc[0] & 0xf;

	ieee80211_check_pending_bar(sta, hdr->addr1, tid);
	}

	if (ieee80211_is_action(mgmt->frame_control) &&
	sdata->vif.type == NL80211_IFTYPE_STATION &&
	mgmt->u.action.category == WLAN_CATEGORY_HT &&
	mgmt->u.action.u.ht_smps.action == WLAN_HT_ACTION_SMPS) {
	/*
	* This update looks racy, but isn't -- if we come
	* here we've definitely got a station that we're
	* talking to, and on a managed interface that can
	* only be the AP. And the only other place updating
	* this variable is before we're associated.
	*/
	switch (mgmt->u.action.u.ht_smps.smps_control) {
	case WLAN_HT_SMPS_CONTROL_DYNAMIC:
	sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_DYNAMIC;
	break;
	case WLAN_HT_SMPS_CONTROL_STATIC:
	sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_STATIC;
	break;
	case WLAN_HT_SMPS_CONTROL_DISABLED:
	default: /* shouldn't happen since we don't send that */
	sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_OFF;
	break;
	}

	ieee80211_queue_work(&local->hw, &local->recalc_smps);
	}
	}

	static void ieee80211_set_bar_pending(struct sta_info *sta, u8 tid, u16 ssn)
	{
	struct tid_ampdu_tx *tid_tx;

	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
	if (!tid_tx)
	return;

	tid_tx->failed_bar_ssn = ssn;
	tid_tx->bar_pending = true;
	}

	/*
	* Use a static threshold for now, best value to be determined
	* by testing ...
	* Should it depend on:
	* - on # of retransmissions
	* - current throughput (higher value for higher tpt)?
	*/
	#define STA_LOST_PKT_THRESHOLD 50

	void ieee80211_tx_status(struct ieee80211_hw hw, struct sk_buff skb)
	{
	struct sk_buff *skb2;
	struct ieee80211_hdr hdr = (struct ieee80211_hdr ) skb->data;
	struct ieee80211_local *local = hw_to_local(hw);
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	u16 frag, type;
	__le16 fc;
	struct ieee80211_supported_band *sband;
	struct ieee80211_tx_status_rtap_hdr *rthdr;
	struct ieee80211_sub_if_data *sdata;
	struct net_device *prev_dev = NULL;
	struct sta_info sta, tmp;
	int retry_count = -1, i;
	int rates_idx = -1;
	bool send_to_cooked;
	bool acked;
	struct ieee80211_bar *bar;
	u16 tid;

	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
	if (info->status.rates[i].idx < 0) {
	break;
	} else if (i >= hw->max_report_rates) {
	/* the HW cannot have attempted that rate */
	info->status.rates[i].idx = -1;
	info->status.rates[i].count = 0;
	break;
	}

	retry_count += info->status.rates[i].count;
	}
	rates_idx = i - 1;

	if (retry_count < 0)
	retry_count = 0;

	rcu_read_lock();

	sband = local->hw.wiphy->bands[info->band];
	fc = hdr->frame_control;

	for_each_sta_info(local, hdr->addr1, sta, tmp) {
	/* skip wrong virtual interface */
	if (memcmp(hdr->addr2, sta->sdata->vif.addr, ETH_ALEN))
	continue;

	acked = !!(info->flags & IEEE80211_TX_STAT_ACK);
	if (!acked && test_sta_flags(sta, WLAN_STA_PS_STA)) {
	/*
	* The STA is in power save mode, so assume
	* that this TX packet failed because of that.
	*/
	ieee80211_handle_filtered_frame(local, sta, skb);
	rcu_read_unlock();
	return;
	}

	if ((local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) &&
	(rates_idx != -1))
	sta->last_tx_rate = info->status.rates[rates_idx];

	if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
	(ieee80211_is_data_qos(fc))) {
	u16 tid, ssn;
	u8 *qc;

	qc = ieee80211_get_qos_ctl(hdr);
	tid = qc[0] & 0xf;
	ssn = ((le16_to_cpu(hdr->seq_ctrl) + 0x10)
	& IEEE80211_SCTL_SEQ);
	ieee80211_send_bar(&sta->sdata->vif, hdr->addr1,
	tid, ssn);
	}

	if (!acked && ieee80211_is_back_req(fc)) {
	u16 control;

	/*
	* BAR failed, store the last SSN and retry sending
	* the BAR when the next unicast transmission on the
	* same TID succeeds.
	*/
	bar = (struct ieee80211_bar *) skb->data;
	control = le16_to_cpu(bar->control);
	if (!(control & IEEE80211_BAR_CTRL_MULTI_TID)) {
	u16 ssn = le16_to_cpu(bar->start_seq_num);

	tid = (control &
	IEEE80211_BAR_CTRL_TID_INFO_MASK) >>
	IEEE80211_BAR_CTRL_TID_INFO_SHIFT;

	ieee80211_set_bar_pending(sta, tid, ssn);
	}
	}

	if (info->flags & IEEE80211_TX_STAT_TX_FILTERED) {
	ieee80211_handle_filtered_frame(local, sta, skb);
	rcu_read_unlock();
	return;
	} else {
	if (!acked)
	sta->tx_retry_failed++;
	sta->tx_retry_count += retry_count;
	}

	rate_control_tx_status(local, sband, sta, skb);
	if (ieee80211_vif_is_mesh(&sta->sdata->vif))
	ieee80211s_update_metric(local, sta, skb);

	if (!(info->flags & IEEE80211_TX_CTL_INJECTED) && acked)
	ieee80211_frame_acked(sta, skb);

	if ((sta->sdata->vif.type == NL80211_IFTYPE_STATION) &&
	(local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS))
	ieee80211_sta_tx_notify(sta->sdata, (void *) skb->data, acked);

	if (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) {
	if (info->flags & IEEE80211_TX_STAT_ACK) {
	if (sta->lost_packets)
	sta->lost_packets = 0;
	} else if (++sta->lost_packets >= STA_LOST_PKT_THRESHOLD) {
	cfg80211_cqm_pktloss_notify(sta->sdata->dev,
	sta->sta.addr,
	sta->lost_packets,
	GFP_ATOMIC);
	sta->lost_packets = 0;
	}
	}
	}

	rcu_read_unlock();

	ieee80211_led_tx(local, 0);

	/* SNMP counters
	* Fragments are passed to low-level drivers as separate skbs, so these
	* are actually fragments, not frames. Update frame counters only for
	* the first fragment of the frame. */

	frag = le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG;
	type = le16_to_cpu(hdr->frame_control) & IEEE80211_FCTL_FTYPE;

	if (info->flags & IEEE80211_TX_STAT_ACK) {
	if (frag == 0) {
	local->dot11TransmittedFrameCount++;
	if (is_multicast_ether_addr(hdr->addr1))
	local->dot11MulticastTransmittedFrameCount++;
	if (retry_count > 0)
	local->dot11RetryCount++;
	if (retry_count > 1)
	local->dot11MultipleRetryCount++;
	}

	/* This counter shall be incremented for an acknowledged MPDU
	* with an individual address in the address 1 field or an MPDU
	* with a multicast address in the address 1 field of type Data
	* or Management. */
	if (!is_multicast_ether_addr(hdr->addr1) \|\|
	type == IEEE80211_FTYPE_DATA \|\|
	type == IEEE80211_FTYPE_MGMT)
	local->dot11TransmittedFragmentCount++;
	} else {
	if (frag == 0)
	local->dot11FailedCount++;
	}

	if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc) &&
	(local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) &&
	!(info->flags & IEEE80211_TX_CTL_INJECTED) &&
	local->ps_sdata && !(local->scanning)) {
	if (info->flags & IEEE80211_TX_STAT_ACK) {
	local->ps_sdata->u.mgd.flags \|=
	IEEE80211_STA_NULLFUNC_ACKED;
	} else
	mod_timer(&local->dynamic_ps_timer, jiffies +
	msecs_to_jiffies(10));
	}

	if (info->flags & IEEE80211_TX_INTFL_NL80211_FRAME_TX) {
	struct ieee80211_work *wk;
	u64 cookie = (unsigned long)skb;

	rcu_read_lock();
	list_for_each_entry_rcu(wk, &local->work_list, list) {
	if (wk->type != IEEE80211_WORK_OFFCHANNEL_TX)
	continue;
	if (wk->offchan_tx.frame != skb)
	continue;
	wk->offchan_tx.frame = NULL;
	break;
	}
	rcu_read_unlock();
	if (local->hw_roc_skb_for_status == skb) {
	cookie = local->hw_roc_cookie ^ 2;
	local->hw_roc_skb_for_status = NULL;
	}

	cfg80211_mgmt_tx_status(
	skb->dev, cookie, skb->data, skb->len,
	!!(info->flags & IEEE80211_TX_STAT_ACK), GFP_ATOMIC);
	}

	/* this was a transmitted frame, but now we want to reuse it */
	skb_orphan(skb);

	/* Need to make a copy before skb->cb gets cleared */
	send_to_cooked = !!(info->flags & IEEE80211_TX_CTL_INJECTED) \|\|
	(type != IEEE80211_FTYPE_DATA);

	/*
	* This is a bit racy but we can avoid a lot of work
	* with this test...
	*/
	if (!local->monitors && (!send_to_cooked \|\| !local->cooked_mntrs)) {
	dev_kfree_skb(skb);
	return;
	}

	/* send frame to monitor interfaces now */

	if (skb_headroom(skb) < sizeof(*rthdr)) {
	printk(KERN_ERR "ieee80211_tx_status: headroom too small\n");
	dev_kfree_skb(skb);
	return;
	}

	rthdr = (struct ieee80211_tx_status_rtap_hdr *)
	skb_push(skb, sizeof(*rthdr));

	memset(rthdr, 0, sizeof(*rthdr));
	rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
	rthdr->hdr.it_present =
	cpu_to_le32((1 << IEEE80211_RADIOTAP_TX_FLAGS) \|
	(1 << IEEE80211_RADIOTAP_DATA_RETRIES) \|
	(1 << IEEE80211_RADIOTAP_RATE));

	if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
	!is_multicast_ether_addr(hdr->addr1))
	rthdr->tx_flags \|= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_FAIL);

	/*
	* XXX: Once radiotap gets the bitmap reset thing the vendor
	* extensions proposal contains, we can actually report
	* the whole set of tries we did.
	*/
	if ((info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS) \|\|
	(info->status.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT))
	rthdr->tx_flags \|= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_CTS);
	else if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
	rthdr->tx_flags \|= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_RTS);
	if (info->status.rates[0].idx >= 0 &&
	!(info->status.rates[0].flags & IEEE80211_TX_RC_MCS))
	rthdr->rate = sband->bitrates[
	info->status.rates[0].idx].bitrate / 5;

	/* for now report the total retry_count */
	rthdr->data_retries = retry_count;

	/* XXX: is this sufficient for BPF? */
	skb_set_mac_header(skb, 0);
	skb->ip_summed = CHECKSUM_UNNECESSARY;
	skb->pkt_type = PACKET_OTHERHOST;
	skb->protocol = htons(ETH_P_802_2);
	memset(skb->cb, 0, sizeof(skb->cb));

	rcu_read_lock();
	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
	if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
	if (!ieee80211_sdata_running(sdata))
	continue;

	if ((sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) &&
	!send_to_cooked)
	continue;

	if (prev_dev) {
	skb2 = skb_clone(skb, GFP_ATOMIC);
	if (skb2) {
	skb2->dev = prev_dev;
	netif_rx(skb2);
	}
	}

	prev_dev = sdata->dev;
	}
	}
	if (prev_dev) {
	skb->dev = prev_dev;
	netif_rx(skb);
	skb = NULL;
	}
	rcu_read_unlock();
	dev_kfree_skb(skb);
	}
	EXPORT_SYMBOL(ieee80211_tx_status);

	void ieee80211_report_low_ack(struct ieee80211_sta *pubsta, u32 num_packets)
	{
	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
	cfg80211_cqm_pktloss_notify(sta->sdata->dev, sta->sta.addr,
	num_packets, GFP_ATOMIC);
	}
	EXPORT_SYMBOL(ieee80211_report_low_ack);