text: /*
   * Copyright 2002-2005, Instant802 Networks, Inc.
   * Copyright 2005-2006, Devicescape Software, Inc.
   * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
   * Copyright 2007	Johannes Berg <johannes@sipsolutions.net>
   * Copyright 2013-2014  Intel Mobile Communications GmbH
   * Copyright (C) 2018 Intel Corporation
   *
   * 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.
   *
   *
   * Transmit and frame generation functions.
   */
  
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/skbuff.h>
  #include <linux/if_vlan.h>
  #include <linux/etherdevice.h>
  #include <linux/bitmap.h>
  #include <linux/rcupdate.h>
  #include <linux/export.h>
  #include <net/net_namespace.h>
  #include <net/ieee80211_radiotap.h>
  #include <net/cfg80211.h>
  #include <net/mac80211.h>
  #include <net/codel.h>
  #include <net/codel_impl.h>
  #include <asm/unaligned.h>
  #include <net/fq_impl.h>
  
  #include "ieee80211_i.h"
  #include "driver-ops.h"
  #include "led.h"
  #include "mesh.h"
  #include "wep.h"
  #include "wpa.h"
  #include "wme.h"
  #include "rate.h"
  
  /* misc utils */
  
  static inline void ieee80211_tx_stats(struct net_device *dev, u32 len)
  {
  	struct pcpu_sw_netstats *tstats = this_cpu_ptr(dev->tstats);
  
  	u64_stats_update_begin(&tstats->syncp);
  	tstats->tx_packets++;
  	tstats->tx_bytes += len;
  	u64_stats_update_end(&tstats->syncp);
  }
  
  static __le16 ieee80211_duration(struct ieee80211_tx_data *tx,
  				 struct sk_buff *skb, int group_addr,
  				 int next_frag_len)
  {
  	int rate, mrate, erp, dur, i, shift = 0;
  	struct ieee80211_rate *txrate;
  	struct ieee80211_local *local = tx->local;
  	struct ieee80211_supported_band *sband;
  	struct ieee80211_hdr *hdr;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  	struct ieee80211_chanctx_conf *chanctx_conf;
  	u32 rate_flags = 0;
  
  	/* assume HW handles this */
  	if (tx->rate.flags & (IEEE80211_TX_RC_MCS | IEEE80211_TX_RC_VHT_MCS))
  		return 0;
  
  	rcu_read_lock();
  	chanctx_conf = rcu_dereference(tx->sdata->vif.chanctx_conf);
  	if (chanctx_conf) {
  		shift = ieee80211_chandef_get_shift(&chanctx_conf->def);
  		rate_flags = ieee80211_chandef_rate_flags(&chanctx_conf->def);
  	}
  	rcu_read_unlock();
  
  	/* uh huh? */
  	if (WARN_ON_ONCE(tx->rate.idx < 0))
  		return 0;
  
  	sband = local->hw.wiphy->bands[info->band];
  	txrate = &sband->bitrates[tx->rate.idx];
  
  	erp = txrate->flags & IEEE80211_RATE_ERP_G;
  
  	/*
  	 * data and mgmt (except PS Poll):
  	 * - during CFP: 32768
  	 * - during contention period:
  	 *   if addr1 is group address: 0
  	 *   if more fragments = 0 and addr1 is individual address: time to
  	 *      transmit one ACK plus SIFS
  	 *   if more fragments = 1 and addr1 is individual address: time to
  	 *      transmit next fragment plus 2 x ACK plus 3 x SIFS
  	 *
  	 * IEEE 802.11, 9.6:
  	 * - control response frame (CTS or ACK) shall be transmitted using the
  	 *   same rate as the immediately previous frame in the frame exchange
  	 *   sequence, if this rate belongs to the PHY mandatory rates, or else
  	 *   at the highest possible rate belonging to the PHY rates in the
  	 *   BSSBasicRateSet
  	 */
  	hdr = (struct ieee80211_hdr *)skb->data;
  	if (ieee80211_is_ctl(hdr->frame_control)) {
  		/* TODO: These control frames are not currently sent by
  		 * mac80211, but should they be implemented, this function
  		 * needs to be updated to support duration field calculation.
  		 *
  		 * RTS: time needed to transmit pending data/mgmt frame plus
  		 *    one CTS frame plus one ACK frame plus 3 x SIFS
  		 * CTS: duration of immediately previous RTS minus time
  		 *    required to transmit CTS and its SIFS
  		 * ACK: 0 if immediately previous directed data/mgmt had
  		 *    more=0, with more=1 duration in ACK frame is duration
  		 *    from previous frame minus time needed to transmit ACK
  		 *    and its SIFS
  		 * PS Poll: BIT(15) | BIT(14) | aid
  		 */
  		return 0;
  	}
  
  	/* data/mgmt */
  	if (0 /* FIX: data/mgmt during CFP */)
  		return cpu_to_le16(32768);
  
  	if (group_addr) /* Group address as the destination - no ACK */
  		return 0;
  
  	/* Individual destination address:
  	 * IEEE 802.11, Ch. 9.6 (after IEEE 802.11g changes)
  	 * CTS and ACK frames shall be transmitted using the highest rate in
  	 * basic rate set that is less than or equal to the rate of the
  	 * immediately previous frame and that is using the same modulation
  	 * (CCK or OFDM). If no basic rate set matches with these requirements,
  	 * the highest mandatory rate of the PHY that is less than or equal to
  	 * the rate of the previous frame is used.
  	 * Mandatory rates for IEEE 802.11g PHY: 1, 2, 5.5, 11, 6, 12, 24 Mbps
  	 */
  	rate = -1;
  	/* use lowest available if everything fails */
  	mrate = sband->bitrates[0].bitrate;
  	for (i = 0; i < sband->n_bitrates; i++) {
  		struct ieee80211_rate *r = &sband->bitrates[i];
  
  		if (r->bitrate > txrate->bitrate)
  			break;
  
  		if ((rate_flags & r->flags) != rate_flags)
  			continue;
  
  		if (tx->sdata->vif.bss_conf.basic_rates & BIT(i))
  			rate = DIV_ROUND_UP(r->bitrate, 1 << shift);
  
  		switch (sband->band) {
  		case NL80211_BAND_2GHZ: {
  			u32 flag;
  			if (tx->sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
  				flag = IEEE80211_RATE_MANDATORY_G;
  			else
  				flag = IEEE80211_RATE_MANDATORY_B;
  			if (r->flags & flag)
  				mrate = r->bitrate;
  			break;
  		}
  		case NL80211_BAND_5GHZ:
  			if (r->flags & IEEE80211_RATE_MANDATORY_A)
  				mrate = r->bitrate;
  			break;
  		case NL80211_BAND_60GHZ:
  			/* TODO, for now fall through */
  		case NUM_NL80211_BANDS:
  			WARN_ON(1);
  			break;
  		}
  	}
  	if (rate == -1) {
  		/* No matching basic rate found; use highest suitable mandatory
  		 * PHY rate */
  		rate = DIV_ROUND_UP(mrate, 1 << shift);
  	}
  
  	/* Don't calculate ACKs for QoS Frames with NoAck Policy set */
  	if (ieee80211_is_data_qos(hdr->frame_control) &&
  	    *(ieee80211_get_qos_ctl(hdr)) & IEEE80211_QOS_CTL_ACK_POLICY_NOACK)
  		dur = 0;
  	else
  		/* Time needed to transmit ACK
  		 * (10 bytes + 4-byte FCS = 112 bits) plus SIFS; rounded up
  		 * to closest integer */
  		dur = ieee80211_frame_duration(sband->band, 10, rate, erp,
  				tx->sdata->vif.bss_conf.use_short_preamble,
  				shift);
  
  	if (next_frag_len) {
  		/* Frame is fragmented: duration increases with time needed to
  		 * transmit next fragment plus ACK and 2 x SIFS. */
  		dur *= 2; /* ACK + SIFS */
  		/* next fragment */
  		dur += ieee80211_frame_duration(sband->band, next_frag_len,
  				txrate->bitrate, erp,
  				tx->sdata->vif.bss_conf.use_short_preamble,
  				shift);
  	}
  
  	return cpu_to_le16(dur);
  }
  
  /* tx handlers */
  static ieee80211_tx_result debug_noinline
  ieee80211_tx_h_dynamic_ps(struct ieee80211_tx_data *tx)
  {
  	struct ieee80211_local *local = tx->local;
  	struct ieee80211_if_managed *ifmgd;
  
  	/* driver doesn't support power save */
  	if (!ieee80211_hw_check(&local->hw, SUPPORTS_PS))
  		return TX_CONTINUE;
  
  	/* hardware does dynamic power save */
  	if (ieee80211_hw_check(&local->hw, SUPPORTS_DYNAMIC_PS))
  		return TX_CONTINUE;
  
  	/* dynamic power save disabled */
  	if (local->hw.conf.dynamic_ps_timeout <= 0)
  		return TX_CONTINUE;
  
  	/* we are scanning, don't enable power save */
  	if (local->scanning)
  		return TX_CONTINUE;
  
  	if (!local->ps_sdata)
  		return TX_CONTINUE;
  
  	/* No point if we're going to suspend */
  	if (local->quiescing)
  		return TX_CONTINUE;
  
  	/* dynamic ps is supported only in managed mode */
  	if (tx->sdata->vif.type != NL80211_IFTYPE_STATION)
  		return TX_CONTINUE;
  
  	ifmgd = &tx->sdata->u.mgd;
  
  	/*
  	 * Don't wakeup from power save if u-apsd is enabled, voip ac has
  	 * u-apsd enabled and the frame is in voip class. This effectively
  	 * means that even if all access categories have u-apsd enabled, in
  	 * practise u-apsd is only used with the voip ac. This is a
  	 * workaround for the case when received voip class packets do not
  	 * have correct qos tag for some reason, due the network or the
  	 * peer application.
  	 *
  	 * Note: ifmgd->uapsd_queues access is racy here. If the value is
  	 * changed via debugfs, user needs to reassociate manually to have
  	 * everything in sync.
  	 */
  	if ((ifmgd->flags & IEEE80211_STA_UAPSD_ENABLED) &&
  	    (ifmgd->uapsd_queues & IEEE80211_WMM_IE_STA_QOSINFO_AC_VO) &&
  	    skb_get_queue_mapping(tx->skb) == IEEE80211_AC_VO)
  		return TX_CONTINUE;
  
  	if (local->hw.conf.flags & IEEE80211_CONF_PS) {
  		ieee80211_stop_queues_by_reason(&local->hw,
  						IEEE80211_MAX_QUEUE_MAP,
  						IEEE80211_QUEUE_STOP_REASON_PS,
  						false);
  		ifmgd->flags &= ~IEEE80211_STA_NULLFUNC_ACKED;
  		ieee80211_queue_work(&local->hw,
  				     &local->dynamic_ps_disable_work);
  	}
  
  	/* Don't restart the timer if we're not disassociated */
  	if (!ifmgd->associated)
  		return TX_CONTINUE;
  
  	mod_timer(&local->dynamic_ps_timer, jiffies +
  		  msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
  
  	return TX_CONTINUE;
  }
  
  static ieee80211_tx_result debug_noinline
  ieee80211_tx_h_check_assoc(struct ieee80211_tx_data *tx)
  {
  
  	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
  	bool assoc = false;
  
  	if (unlikely(info->flags & IEEE80211_TX_CTL_INJECTED))
  		return TX_CONTINUE;
  
  	if (unlikely(test_bit(SCAN_SW_SCANNING, &tx->local->scanning)) &&
  	    test_bit(SDATA_STATE_OFFCHANNEL, &tx->sdata->state) &&
  	    !ieee80211_is_probe_req(hdr->frame_control) &&
  	    !ieee80211_is_nullfunc(hdr->frame_control))
  		/*
  		 * When software scanning only nullfunc frames (to notify
  		 * the sleep state to the AP) and probe requests (for the
  		 * active scan) are allowed, all other frames should not be
  		 * sent and we should not get here, but if we do
  		 * nonetheless, drop them to avoid sending them
  		 * off-channel. See the link below and
  		 * ieee80211_start_scan() for more.
  		 *
  		 * http://article.gmane.org/gmane.linux.kernel.wireless.general/30089
  		 */
  		return TX_DROP;
  
  	if (tx->sdata->vif.type == NL80211_IFTYPE_OCB)
  		return TX_CONTINUE;
  
  	if (tx->sdata->vif.type == NL80211_IFTYPE_WDS)
  		return TX_CONTINUE;
  
  	if (tx->flags & IEEE80211_TX_PS_BUFFERED)
  		return TX_CONTINUE;
  
  	if (tx->sta)
  		assoc = test_sta_flag(tx->sta, WLAN_STA_ASSOC);
  
  	if (likely(tx->flags & IEEE80211_TX_UNICAST)) {
  		if (unlikely(!assoc &&
  			     ieee80211_is_data(hdr->frame_control))) {
  #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
  			sdata_info(tx->sdata,
  				   "dropped data frame to not associated station %pM\n",
  				   hdr->addr1);
  #endif
  			I802_DEBUG_INC(tx->local->tx_handlers_drop_not_assoc);
  			return TX_DROP;
  		}
  	} else if (unlikely(ieee80211_is_data(hdr->frame_control) &&
  			    ieee80211_vif_get_num_mcast_if(tx->sdata) == 0)) {
  		/*
  		 * No associated STAs - no need to send multicast
  		 * frames.
  		 */
  		return TX_DROP;
  	}
  
  	return TX_CONTINUE;
  }
  
  /* This function is called whenever the AP is about to exceed the maximum limit
   * of buffered frames for power saving STAs. This situation should not really
   * happen often during normal operation, so dropping the oldest buffered packet
   * from each queue should be OK to make some room for new frames. */
  static void purge_old_ps_buffers(struct ieee80211_local *local)
  {
  	int total = 0, purged = 0;
  	struct sk_buff *skb;
  	struct ieee80211_sub_if_data *sdata;
  	struct sta_info *sta;
  
  	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
  		struct ps_data *ps;
  
  		if (sdata->vif.type == NL80211_IFTYPE_AP)
  			ps = &sdata->u.ap.ps;
  		else if (ieee80211_vif_is_mesh(&sdata->vif))
  			ps = &sdata->u.mesh.ps;
  		else
  			continue;
  
  		skb = skb_dequeue(&ps->bc_buf);
  		if (skb) {
  			purged++;
  			ieee80211_free_txskb(&local->hw, skb);
  		}
  		total += skb_queue_len(&ps->bc_buf);
  	}
  
  	/*
  	 * Drop one frame from each station from the lowest-priority
  	 * AC that has frames at all.
  	 */
  	list_for_each_entry_rcu(sta, &local->sta_list, list) {
  		int ac;
  
  		for (ac = IEEE80211_AC_BK; ac >= IEEE80211_AC_VO; ac--) {
  			skb = skb_dequeue(&sta->ps_tx_buf[ac]);
  			total += skb_queue_len(&sta->ps_tx_buf[ac]);
  			if (skb) {
  				purged++;
  				ieee80211_free_txskb(&local->hw, skb);
  				break;
  			}
  		}
  	}
  
  	local->total_ps_buffered = total;
  	ps_dbg_hw(&local->hw, "PS buffers full - purged %d frames\n", purged);
  }
  
  static ieee80211_tx_result
  ieee80211_tx_h_multicast_ps_buf(struct ieee80211_tx_data *tx)
  {
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
  	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
  	struct ps_data *ps;
  
  	/*
  	 * broadcast/multicast frame
  	 *
  	 * If any of the associated/peer stations is in power save mode,
  	 * the frame is buffered to be sent after DTIM beacon frame.
  	 * This is done either by the hardware or us.
  	 */
  
  	/* powersaving STAs currently only in AP/VLAN/mesh mode */
  	if (tx->sdata->vif.type == NL80211_IFTYPE_AP ||
  	    tx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
  		if (!tx->sdata->bss)
  			return TX_CONTINUE;
  
  		ps = &tx->sdata->bss->ps;
  	} else if (ieee80211_vif_is_mesh(&tx->sdata->vif)) {
  		ps = &tx->sdata->u.mesh.ps;
  	} else {
  		return TX_CONTINUE;
  	}
  
  
  	/* no buffering for ordered frames */
  	if (ieee80211_has_order(hdr->frame_control))
  		return TX_CONTINUE;
  
  	if (ieee80211_is_probe_req(hdr->frame_control))
  		return TX_CONTINUE;
  
  	if (ieee80211_hw_check(&tx->local->hw, QUEUE_CONTROL))
  		info->hw_queue = tx->sdata->vif.cab_queue;
  
  	/* no stations in PS mode */
  	if (!atomic_read(&ps->num_sta_ps))
  		return TX_CONTINUE;
  
  	info->flags |= IEEE80211_TX_CTL_SEND_AFTER_DTIM;
  
  	/* device releases frame after DTIM beacon */
  	if (!ieee80211_hw_check(&tx->local->hw, HOST_BROADCAST_PS_BUFFERING))
  		return TX_CONTINUE;
  
  	/* buffered in mac80211 */
  	if (tx->local->total_ps_buffered >= TOTAL_MAX_TX_BUFFER)
  		purge_old_ps_buffers(tx->local);
  
  	if (skb_queue_len(&ps->bc_buf) >= AP_MAX_BC_BUFFER) {
  		ps_dbg(tx->sdata,
  		       "BC TX buffer full - dropping the oldest frame\n");
  		ieee80211_free_txskb(&tx->local->hw, skb_dequeue(&ps->bc_buf));
  	} else
  		tx->local->total_ps_buffered++;
  
  	skb_queue_tail(&ps->bc_buf, tx->skb);
  
  	return TX_QUEUED;
  }
  
  static int ieee80211_use_mfp(__le16 fc, struct sta_info *sta,
  			     struct sk_buff *skb)
  {
  	if (!ieee80211_is_mgmt(fc))
  		return 0;
  
  	if (sta == NULL || !test_sta_flag(sta, WLAN_STA_MFP))
  		return 0;
  
  	if (!ieee80211_is_robust_mgmt_frame(skb))
  		return 0;
  
  	return 1;
  }
  
  static ieee80211_tx_result
  ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
  {
  	struct sta_info *sta = tx->sta;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
  	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
  	struct ieee80211_local *local = tx->local;
  
  	if (unlikely(!sta))
  		return TX_CONTINUE;
  
  	if (unlikely((test_sta_flag(sta, WLAN_STA_PS_STA) ||
  		      test_sta_flag(sta, WLAN_STA_PS_DRIVER) ||
  		      test_sta_flag(sta, WLAN_STA_PS_DELIVER)) &&
  		     !(info->flags & IEEE80211_TX_CTL_NO_PS_BUFFER))) {
  		int ac = skb_get_queue_mapping(tx->skb);
  
  		if (ieee80211_is_mgmt(hdr->frame_control) &&
  		    !ieee80211_is_bufferable_mmpdu(hdr->frame_control)) {
  			info->flags |= IEEE80211_TX_CTL_NO_PS_BUFFER;
  			return TX_CONTINUE;
  		}
  
  		ps_dbg(sta->sdata, "STA %pM aid %d: PS buffer for AC %d\n",
  		       sta->sta.addr, sta->sta.aid, ac);
  		if (tx->local->total_ps_buffered >= TOTAL_MAX_TX_BUFFER)
  			purge_old_ps_buffers(tx->local);
  
  		/* sync with ieee80211_sta_ps_deliver_wakeup */
  		spin_lock(&sta->ps_lock);
  		/*
  		 * STA woke up the meantime and all the frames on ps_tx_buf have
  		 * been queued to pending queue. No reordering can happen, go
  		 * ahead and Tx the packet.
  		 */
  		if (!test_sta_flag(sta, WLAN_STA_PS_STA) &&
  		    !test_sta_flag(sta, WLAN_STA_PS_DRIVER) &&
  		    !test_sta_flag(sta, WLAN_STA_PS_DELIVER)) {
  			spin_unlock(&sta->ps_lock);
  			return TX_CONTINUE;
  		}
  
  		if (skb_queue_len(&sta->ps_tx_buf[ac]) >= STA_MAX_TX_BUFFER) {
  			struct sk_buff *old = skb_dequeue(&sta->ps_tx_buf[ac]);
  			ps_dbg(tx->sdata,
  			       "STA %pM TX buffer for AC %d full - dropping oldest frame\n",
  			       sta->sta.addr, ac);
  			ieee80211_free_txskb(&local->hw, old);
  		} else
  			tx->local->total_ps_buffered++;
  
  		info->control.jiffies = jiffies;
  		info->control.vif = &tx->sdata->vif;
  		info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
  		info->flags &= ~IEEE80211_TX_TEMPORARY_FLAGS;
  		skb_queue_tail(&sta->ps_tx_buf[ac], tx->skb);
  		spin_unlock(&sta->ps_lock);
  
  		if (!timer_pending(&local->sta_cleanup))
  			mod_timer(&local->sta_cleanup,
  				  round_jiffies(jiffies +
  						STA_INFO_CLEANUP_INTERVAL));
  
  		/*
  		 * We queued up some frames, so the TIM bit might
  		 * need to be set, recalculate it.
  		 */
  		sta_info_recalc_tim(sta);
  
  		return TX_QUEUED;
  	} else if (unlikely(test_sta_flag(sta, WLAN_STA_PS_STA))) {
  		ps_dbg(tx->sdata,
  		       "STA %pM in PS mode, but polling/in SP -> send frame\n",
  		       sta->sta.addr);
  	}
  
  	return TX_CONTINUE;
  }
  
  static ieee80211_tx_result debug_noinline
  ieee80211_tx_h_ps_buf(struct ieee80211_tx_data *tx)
  {
  	if (unlikely(tx->flags & IEEE80211_TX_PS_BUFFERED))
  		return TX_CONTINUE;
  
  	if (tx->flags & IEEE80211_TX_UNICAST)
  		return ieee80211_tx_h_unicast_ps_buf(tx);
  	else
  		return ieee80211_tx_h_multicast_ps_buf(tx);
  }
  
  static ieee80211_tx_result debug_noinline
  ieee80211_tx_h_check_control_port_protocol(struct ieee80211_tx_data *tx)
  {
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
  
  	if (unlikely(tx->sdata->control_port_protocol == tx->skb->protocol)) {
  		if (tx->sdata->control_port_no_encrypt)
  			info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
  		info->control.flags |= IEEE80211_TX_CTRL_PORT_CTRL_PROTO;
  		info->flags |= IEEE80211_TX_CTL_USE_MINRATE;
  	}
  
  	return TX_CONTINUE;
  }
  
  static ieee80211_tx_result debug_noinline
  ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx)
  {
  	struct ieee80211_key *key;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
  	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
  
  	if (unlikely(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT))
  		tx->key = NULL;
  	else if (tx->sta &&
  		 (key = rcu_dereference(tx->sta->ptk[tx->sta->ptk_idx])))
  		tx->key = key;
  	else if (ieee80211_is_group_privacy_action(tx->skb) &&
  		(key = rcu_dereference(tx->sdata->default_multicast_key)))
  		tx->key = key;
  	else if (ieee80211_is_mgmt(hdr->frame_control) &&
  		 is_multicast_ether_addr(hdr->addr1) &&
  		 ieee80211_is_robust_mgmt_frame(tx->skb) &&
  		 (key = rcu_dereference(tx->sdata->default_mgmt_key)))
  		tx->key = key;
  	else if (is_multicast_ether_addr(hdr->addr1) &&
  		 (key = rcu_dereference(tx->sdata->default_multicast_key)))
  		tx->key = key;
  	else if (!is_multicast_ether_addr(hdr->addr1) &&
  		 (key = rcu_dereference(tx->sdata->default_unicast_key)))
  		tx->key = key;
  	else
  		tx->key = NULL;
  
  	if (tx->key) {
  		bool skip_hw = false;
  
  		/* TODO: add threshold stuff again */
  
  		switch (tx->key->conf.cipher) {
  		case WLAN_CIPHER_SUITE_WEP40:
  		case WLAN_CIPHER_SUITE_WEP104:
  		case WLAN_CIPHER_SUITE_TKIP:
  			if (!ieee80211_is_data_present(hdr->frame_control))
  				tx->key = NULL;
  			break;
  		case WLAN_CIPHER_SUITE_CCMP:
  		case WLAN_CIPHER_SUITE_CCMP_256:
  		case WLAN_CIPHER_SUITE_GCMP:
  		case WLAN_CIPHER_SUITE_GCMP_256:
  			if (!ieee80211_is_data_present(hdr->frame_control) &&
  			    !ieee80211_use_mfp(hdr->frame_control, tx->sta,
  					       tx->skb) &&
  			    !ieee80211_is_group_privacy_action(tx->skb))
  				tx->key = NULL;
  			else
  				skip_hw = (tx->key->conf.flags &
  					   IEEE80211_KEY_FLAG_SW_MGMT_TX) &&
  					ieee80211_is_mgmt(hdr->frame_control);
  			break;
  		case WLAN_CIPHER_SUITE_AES_CMAC:
  		case WLAN_CIPHER_SUITE_BIP_CMAC_256:
  		case WLAN_CIPHER_SUITE_BIP_GMAC_128:
  		case WLAN_CIPHER_SUITE_BIP_GMAC_256:
  			if (!ieee80211_is_mgmt(hdr->frame_control))
  				tx->key = NULL;
  			break;
  		}
  
  		if (unlikely(tx->key && tx->key->flags & KEY_FLAG_TAINTED &&
  			     !ieee80211_is_deauth(hdr->frame_control)))
  			return TX_DROP;
  
  		if (!skip_hw && tx->key &&
  		    tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
  			info->control.hw_key = &tx->key->conf;
  	}
  
  	return TX_CONTINUE;
  }
  
  static ieee80211_tx_result debug_noinline
  ieee80211_tx_h_rate_ctrl(struct ieee80211_tx_data *tx)
  {
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
  	struct ieee80211_hdr *hdr = (void *)tx->skb->data;
  	struct ieee80211_supported_band *sband;
  	u32 len;
  	struct ieee80211_tx_rate_control txrc;
  	struct ieee80211_sta_rates *ratetbl = NULL;
  	bool assoc = false;
  
  	memset(&txrc, 0, sizeof(txrc));
  
  	sband = tx->local->hw.wiphy->bands[info->band];
  
  	len = min_t(u32, tx->skb->len + FCS_LEN,
  			 tx->local->hw.wiphy->frag_threshold);
  
  	/* set up the tx rate control struct we give the RC algo */
  	txrc.hw = &tx->local->hw;
  	txrc.sband = sband;
  	txrc.bss_conf = &tx->sdata->vif.bss_conf;
  	txrc.skb = tx->skb;
  	txrc.reported_rate.idx = -1;
  	txrc.rate_idx_mask = tx->sdata->rc_rateidx_mask[info->band];
  
  	if (tx->sdata->rc_has_mcs_mask[info->band])
  		txrc.rate_idx_mcs_mask =
  			tx->sdata->rc_rateidx_mcs_mask[info->band];
  
  	txrc.bss = (tx->sdata->vif.type == NL80211_IFTYPE_AP ||
  		    tx->sdata->vif.type == NL80211_IFTYPE_MESH_POINT ||
  		    tx->sdata->vif.type == NL80211_IFTYPE_ADHOC ||
  		    tx->sdata->vif.type == NL80211_IFTYPE_OCB);
  
  	/* set up RTS protection if desired */
  	if (len > tx->local->hw.wiphy->rts_threshold) {
  		txrc.rts = true;
  	}
  
  	info->control.use_rts = txrc.rts;
  	info->control.use_cts_prot = tx->sdata->vif.bss_conf.use_cts_prot;
  
  	/*
  	 * Use short preamble if the BSS can handle it, but not for
  	 * management frames unless we know the receiver can handle
  	 * that -- the management frame might be to a station that
  	 * just wants a probe response.
  	 */
  	if (tx->sdata->vif.bss_conf.use_short_preamble &&
  	    (ieee80211_is_data(hdr->frame_control) ||
  	     (tx->sta && test_sta_flag(tx->sta, WLAN_STA_SHORT_PREAMBLE))))
  		txrc.short_preamble = true;
  
  	info->control.short_preamble = txrc.short_preamble;
  
  	/* don't ask rate control when rate already injected via radiotap */
  	if (info->control.flags & IEEE80211_TX_CTRL_RATE_INJECT)
  		return TX_CONTINUE;
  
  	if (tx->sta)
  		assoc = test_sta_flag(tx->sta, WLAN_STA_ASSOC);
  
  	/*
  	 * Lets not bother rate control if we're associated and cannot
  	 * talk to the sta. This should not happen.
  	 */
  	if (WARN(test_bit(SCAN_SW_SCANNING, &tx->local->scanning) && assoc &&
  		 !rate_usable_index_exists(sband, &tx->sta->sta),
  		 "%s: Dropped data frame as no usable bitrate found while "
  		 "scanning and associated. Target station: "
  		 "%pM on %d GHz band\n",
  		 tx->sdata->name, hdr->addr1,
  		 info->band ? 5 : 2))
  		return TX_DROP;
  
  	/*
  	 * If we're associated with the sta at this point we know we can at
  	 * least send the frame at the lowest bit rate.
  	 */
  	rate_control_get_rate(tx->sdata, tx->sta, &txrc);
  
  	if (tx->sta && !info->control.skip_table)
  		ratetbl = rcu_dereference(tx->sta->sta.rates);
  
  	if (unlikely(info->control.rates[0].idx < 0)) {
  		if (ratetbl) {
  			struct ieee80211_tx_rate rate = {
  				.idx = ratetbl->rate[0].idx,
  				.flags = ratetbl->rate[0].flags,
  				.count = ratetbl->rate[0].count
  			};
  
  			if (ratetbl->rate[0].idx < 0)
  				return TX_DROP;
  
  			tx->rate = rate;
  		} else {
  			return TX_DROP;
  		}
  	} else {
  		tx->rate = info->control.rates[0];
  	}
  
  	if (txrc.reported_rate.idx < 0) {
  		txrc.reported_rate = tx->rate;
  		if (tx->sta && ieee80211_is_data(hdr->frame_control))
  			tx->sta->tx_stats.last_rate = txrc.reported_rate;
  	} else if (tx->sta)
  		tx->sta->tx_stats.last_rate = txrc.reported_rate;
  
  	if (ratetbl)
  		return TX_CONTINUE;
  
  	if (unlikely(!info->control.rates[0].count))
  		info->control.rates[0].count = 1;
  
  	if (WARN_ON_ONCE((info->control.rates[0].count > 1) &&
  			 (info->flags & IEEE80211_TX_CTL_NO_ACK)))
  		info->control.rates[0].count = 1;
  
  	return TX_CONTINUE;
  }
  
  static __le16 ieee80211_tx_next_seq(struct sta_info *sta, int tid)
  {
  	u16 *seq = &sta->tid_seq[tid];
  	__le16 ret = cpu_to_le16(*seq);
  
  	/* Increase the sequence number. */
  	*seq = (*seq + 0x10) & IEEE80211_SCTL_SEQ;
  
  	return ret;
  }
  
  static ieee80211_tx_result debug_noinline
  ieee80211_tx_h_sequence(struct ieee80211_tx_data *tx)
  {
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
  	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
  	int tid;
  
  	/*
  	 * Packet injection may want to control the sequence
  	 * number, if we have no matching interface then we
  	 * neither assign one ourselves nor ask the driver to.
  	 */
  	if (unlikely(info->control.vif->type == NL80211_IFTYPE_MONITOR))
  		return TX_CONTINUE;
  
  	if (unlikely(ieee80211_is_ctl(hdr->frame_control)))
  		return TX_CONTINUE;
  
  	if (ieee80211_hdrlen(hdr->frame_control) < 24)
  		return TX_CONTINUE;
  
  	if (ieee80211_is_qos_nullfunc(hdr->frame_control))
  		return TX_CONTINUE;
  
  	/*
  	 * Anything but QoS data that has a sequence number field
  	 * (is long enough) gets a sequence number from the global
  	 * counter.  QoS data frames with a multicast destination
  	 * also use the global counter (802.11-2012 9.3.2.10).
  	 */
  	if (!ieee80211_is_data_qos(hdr->frame_control) ||
  	    is_multicast_ether_addr(hdr->addr1)) {
  		/* driver should assign sequence number */
  		info->flags |= IEEE80211_TX_CTL_ASSIGN_SEQ;
  		/* for pure STA mode without beacons, we can do it */
  		hdr->seq_ctrl = cpu_to_le16(tx->sdata->sequence_number);
  		tx->sdata->sequence_number += 0x10;
  		if (tx->sta)
  			tx->sta->tx_stats.msdu[IEEE80211_NUM_TIDS]++;
  		return TX_CONTINUE;
  	}
  
  	/*
  	 * This should be true for injected/management frames only, for
  	 * management frames we have set the IEEE80211_TX_CTL_ASSIGN_SEQ
  	 * above since they are not QoS-data frames.
  	 */
  	if (!tx->sta)
  		return TX_CONTINUE;
  
  	/* include per-STA, per-TID sequence counter */
  	tid = ieee80211_get_tid(hdr);
  	tx->sta->tx_stats.msdu[tid]++;
  
  	hdr->seq_ctrl = ieee80211_tx_next_seq(tx->sta, tid);
  
  	return TX_CONTINUE;
  }
  
  static int ieee80211_fragment(struct ieee80211_tx_data *tx,
  			      struct sk_buff *skb, int hdrlen,
  			      int frag_threshold)
  {
  	struct ieee80211_local *local = tx->local;
  	struct ieee80211_tx_info *info;
  	struct sk_buff *tmp;
  	int per_fragm = frag_threshold - hdrlen - FCS_LEN;
  	int pos = hdrlen + per_fragm;
  	int rem = skb->len - hdrlen - per_fragm;
  
  	if (WARN_ON(rem < 0))
  		return -EINVAL;
  
  	/* first fragment was already added to queue by caller */
  
  	while (rem) {
  		int fraglen = per_fragm;
  
  		if (fraglen > rem)
  			fraglen = rem;
  		rem -= fraglen;
  		tmp = dev_alloc_skb(local->tx_headroom +
  				    frag_threshold +
  				    tx->sdata->encrypt_headroom +
  				    IEEE80211_ENCRYPT_TAILROOM);
  		if (!tmp)
  			return -ENOMEM;
  
  		__skb_queue_tail(&tx->skbs, tmp);
  
  		skb_reserve(tmp,
  			    local->tx_headroom + tx->sdata->encrypt_headroom);
  
  		/* copy control information */
  		memcpy(tmp->cb, skb->cb, sizeof(tmp->cb));
  
  		info = IEEE80211_SKB_CB(tmp);
  		info->flags &= ~(IEEE80211_TX_CTL_CLEAR_PS_FILT |
  				 IEEE80211_TX_CTL_FIRST_FRAGMENT);
  
  		if (rem)
  			info->flags |= IEEE80211_TX_CTL_MORE_FRAMES;
  
  		skb_copy_queue_mapping(tmp, skb);
  		tmp->priority = skb->priority;
  		tmp->dev = skb->dev;
  
  		/* copy header and data */
  		skb_put_data(tmp, skb->data, hdrlen);
  		skb_put_data(tmp, skb->data + pos, fraglen);
  
  		pos += fraglen;
  	}
  
  	/* adjust first fragment's length */
  	skb_trim(skb, hdrlen + per_fragm);
  	return 0;
  }
  
  static ieee80211_tx_result debug_noinline
  ieee80211_tx_h_fragment(struct ieee80211_tx_data *tx)
  {
  	struct sk_buff *skb = tx->skb;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  	struct ieee80211_hdr *hdr = (void *)skb->data;
  	int frag_threshold = tx->local->hw.wiphy->frag_threshold;
  	int hdrlen;
  	int fragnum;
  
  	/* no matter what happens, tx->skb moves to tx->skbs */
  	__skb_queue_tail(&tx->skbs, skb);
  	tx->skb = NULL;
  
  	if (info->flags & IEEE80211_TX_CTL_DONTFRAG)
  		return TX_CONTINUE;
  
  	if (ieee80211_hw_check(&tx->local->hw, SUPPORTS_TX_FRAG))
  		return TX_CONTINUE;
  
  	/*
  	 * Warn when submitting a fragmented A-MPDU frame and drop it.
  	 * This scenario is handled in ieee80211_tx_prepare but extra
  	 * caution taken here as fragmented ampdu may cause Tx stop.
  	 */
  	if (WARN_ON(info->flags & IEEE80211_TX_CTL_AMPDU))
  		return TX_DROP;
  
  	hdrlen = ieee80211_hdrlen(hdr->frame_control);
  
  	/* internal error, why isn't DONTFRAG set? */
  	if (WARN_ON(skb->len + FCS_LEN <= frag_threshold))
  		return TX_DROP;
  
  	/*
  	 * Now fragment the frame. This will allocate all the fragments and
  	 * chain them (using skb as the first fragment) to skb->next.
  	 * During transmission, we will remove the successfully transmitted
  	 * fragments from this list. When the low-level driver rejects one
  	 * of the fragments then we will simply pretend to accept the skb
  	 * but store it away as pending.
  	 */
  	if (ieee80211_fragment(tx, skb, hdrlen, frag_threshold))
  		return TX_DROP;
  
  	/* update duration/seq/flags of fragments */
  	fragnum = 0;
  
  	skb_queue_walk(&tx->skbs, skb) {
  		const __le16 morefrags = cpu_to_le16(IEEE80211_FCTL_MOREFRAGS);
  
  		hdr = (void *)skb->data;
  		info = IEEE80211_SKB_CB(skb);
  
  		if (!skb_queue_is_last(&tx->skbs, skb)) {
  			hdr->frame_control |= morefrags;
  			/*
  			 * No multi-rate retries for fragmented frames, that
  			 * would completely throw off the NAV at other STAs.
  			 */
  			info->control.rates[1].idx = -1;
  			info->control.rates[2].idx = -1;
  			info->control.rates[3].idx = -1;
  			BUILD_BUG_ON(IEEE80211_TX_MAX_RATES != 4);
  			info->flags &= ~IEEE80211_TX_CTL_RATE_CTRL_PROBE;
  		} else {
  			hdr->frame_control &= ~morefrags;
  		}
  		hdr->seq_ctrl |= cpu_to_le16(fragnum & IEEE80211_SCTL_FRAG);
  		fragnum++;
  	}
  
  	return TX_CONTINUE;
  }
  
  static ieee80211_tx_result debug_noinline
  ieee80211_tx_h_stats(struct ieee80211_tx_data *tx)
  {
  	struct sk_buff *skb;
  	int ac = -1;
  
  	if (!tx->sta)
  		return TX_CONTINUE;
  
  	skb_queue_walk(&tx->skbs, skb) {
  		ac = skb_get_queue_mapping(skb);
  		tx->sta->tx_stats.bytes[ac] += skb->len;
  	}
  	if (ac >= 0)
  		tx->sta->tx_stats.packets[ac]++;
  
  	return TX_CONTINUE;
  }
  
  static ieee80211_tx_result debug_noinline
  ieee80211_tx_h_encrypt(struct ieee80211_tx_data *tx)
  {
  	if (!tx->key)
  		return TX_CONTINUE;
  
  	switch (tx->key->conf.cipher) {
  	case WLAN_CIPHER_SUITE_WEP40:
  	case WLAN_CIPHER_SUITE_WEP104:
  		return ieee80211_crypto_wep_encrypt(tx);
  	case WLAN_CIPHER_SUITE_TKIP:
  		return ieee80211_crypto_tkip_encrypt(tx);
  	case WLAN_CIPHER_SUITE_CCMP:
  		return ieee80211_crypto_ccmp_encrypt(
  			tx, IEEE80211_CCMP_MIC_LEN);
  	case WLAN_CIPHER_SUITE_CCMP_256:
  		return ieee80211_crypto_ccmp_encrypt(
  			tx, IEEE80211_CCMP_256_MIC_LEN);
  	case WLAN_CIPHER_SUITE_AES_CMAC:
  		return ieee80211_crypto_aes_cmac_encrypt(tx);
  	case WLAN_CIPHER_SUITE_BIP_CMAC_256:
  		return ieee80211_crypto_aes_cmac_256_encrypt(tx);
  	case WLAN_CIPHER_SUITE_BIP_GMAC_128:
  	case WLAN_CIPHER_SUITE_BIP_GMAC_256:
  		return ieee80211_crypto_aes_gmac_encrypt(tx);
  	case WLAN_CIPHER_SUITE_GCMP:
  	case WLAN_CIPHER_SUITE_GCMP_256:
  		return ieee80211_crypto_gcmp_encrypt(tx);
  	default:
  		return ieee80211_crypto_hw_encrypt(tx);
  	}
  
  	return TX_DROP;
  }
  
  static ieee80211_tx_result debug_noinline
  ieee80211_tx_h_calculate_duration(struct ieee80211_tx_data *tx)
  {
  	struct sk_buff *skb;
  	struct ieee80211_hdr *hdr;
  	int next_len;
  	bool group_addr;
  
  	skb_queue_walk(&tx->skbs, skb) {
  		hdr = (void *) skb->data;
  		if (unlikely(ieee80211_is_pspoll(hdr->frame_control)))
  			break; /* must not overwrite AID */
  		if (!skb_queue_is_last(&tx->skbs, skb)) {
  			struct sk_buff *next = skb_queue_next(&tx->skbs, skb);
  			next_len = next->len;
  		} else
  			next_len = 0;
  		group_addr = is_multicast_ether_addr(hdr->addr1);
  
  		hdr->duration_id =
  			ieee80211_duration(tx, skb, group_addr, next_len);
  	}
  
  	return TX_CONTINUE;
  }
  
  /* actual transmit path */
  
  static bool ieee80211_tx_prep_agg(struct ieee80211_tx_data *tx,
  				  struct sk_buff *skb,
  				  struct ieee80211_tx_info *info,
  				  struct tid_ampdu_tx *tid_tx,
  				  int tid)
  {
  	bool queued = false;
  	bool reset_agg_timer = false;
  	struct sk_buff *purge_skb = NULL;
  
  	if (test_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state)) {
  		info->flags |= IEEE80211_TX_CTL_AMPDU;
  		reset_agg_timer = true;
  	} else if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
  		/*
  		 * nothing -- this aggregation session is being started
  		 * but that might still fail with the driver
  		 */
  	} else if (!tx->sta->sta.txq[tid]) {
  		spin_lock(&tx->sta->lock);
  		/*
  		 * Need to re-check now, because we may get here
  		 *
  		 *  1) in the window during which the setup is actually
  		 *     already done, but not marked yet because not all
  		 *     packets are spliced over to the driver pending
  		 *     queue yet -- if this happened we acquire the lock
  		 *     either before or after the splice happens, but
  		 *     need to recheck which of these cases happened.
  		 *
  		 *  2) during session teardown, if the OPERATIONAL bit
  		 *     was cleared due to the teardown but the pointer
  		 *     hasn't been assigned NULL yet (or we loaded it
  		 *     before it was assigned) -- in this case it may
  		 *     now be NULL which means we should just let the
  		 *     packet pass through because splicing the frames
  		 *     back is already done.
  		 */
  		tid_tx = rcu_dereference_protected_tid_tx(tx->sta, tid);
  
  		if (!tid_tx) {
  			/* do nothing, let packet pass through */
  		} else if (test_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state)) {
  			info->flags |= IEEE80211_TX_CTL_AMPDU;
  			reset_agg_timer = true;
  		} else {
  			queued = true;
  			if (info->flags & IEEE80211_TX_CTL_NO_PS_BUFFER) {
  				clear_sta_flag(tx->sta, WLAN_STA_SP);
  				ps_dbg(tx->sta->sdata,
  				       "STA %pM aid %d: SP frame queued, close the SP w/o telling the peer\n",
  				       tx->sta->sta.addr, tx->sta->sta.aid);
  			}
  			info->control.vif = &tx->sdata->vif;
  			info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
  			info->flags &= ~IEEE80211_TX_TEMPORARY_FLAGS;
  			__skb_queue_tail(&tid_tx->pending, skb);
  			if (skb_queue_len(&tid_tx->pending) > STA_MAX_TX_BUFFER)
  				purge_skb = __skb_dequeue(&tid_tx->pending);
  		}
  		spin_unlock(&tx->sta->lock);
  
  		if (purge_skb)
  			ieee80211_free_txskb(&tx->local->hw, purge_skb);
  	}
  
  	/* reset session timer */
  	if (reset_agg_timer)
  		tid_tx->last_tx = jiffies;
  
  	return queued;
  }
  
  /*
   * initialises @tx
   * pass %NULL for the station if unknown, a valid pointer if known
   * or an ERR_PTR() if the station is known not to exist
   */
  static ieee80211_tx_result
  ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata,
  		     struct ieee80211_tx_data *tx,
  		     struct sta_info *sta, struct sk_buff *skb)
  {
  	struct ieee80211_local *local = sdata->local;
  	struct ieee80211_hdr *hdr;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  	int tid;
  
  	memset(tx, 0, sizeof(*tx));
  	tx->skb = skb;
  	tx->local = local;
  	tx->sdata = sdata;
  	__skb_queue_head_init(&tx->skbs);
  
  	/*
  	 * If this flag is set to true anywhere, and we get here,
  	 * we are doing the needed processing, so remove the flag
  	 * now.
  	 */
  	info->flags &= ~IEEE80211_TX_INTFL_NEED_TXPROCESSING;
  
  	hdr = (struct ieee80211_hdr *) skb->data;
  
  	if (likely(sta)) {
  		if (!IS_ERR(sta))
  			tx->sta = sta;
  	} else {
  		if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
  			tx->sta = rcu_dereference(sdata->u.vlan.sta);
  			if (!tx->sta && sdata->wdev.use_4addr)
  				return TX_DROP;
  		} else if (info->flags & (IEEE80211_TX_INTFL_NL80211_FRAME_TX |
  					  IEEE80211_TX_CTL_INJECTED) ||
  			   tx->sdata->control_port_protocol == tx->skb->protocol) {
  			tx->sta = sta_info_get_bss(sdata, hdr->addr1);
  		}
  		if (!tx->sta && !is_multicast_ether_addr(hdr->addr1))
  			tx->sta = sta_info_get(sdata, hdr->addr1);
  	}
  
  	if (tx->sta && ieee80211_is_data_qos(hdr->frame_control) &&
  	    !ieee80211_is_qos_nullfunc(hdr->frame_control) &&
  	    ieee80211_hw_check(&local->hw, AMPDU_AGGREGATION) &&
  	    !ieee80211_hw_check(&local->hw, TX_AMPDU_SETUP_IN_HW)) {
  		struct tid_ampdu_tx *tid_tx;
  
  		tid = ieee80211_get_tid(hdr);
  
  		tid_tx = rcu_dereference(tx->sta->ampdu_mlme.tid_tx[tid]);
  		if (tid_tx) {
  			bool queued;
  
  			queued = ieee80211_tx_prep_agg(tx, skb, info,
  						       tid_tx, tid);
  
  			if (unlikely(queued))
  				return TX_QUEUED;
  		}
  	}
  
  	if (is_multicast_ether_addr(hdr->addr1)) {
  		tx->flags &= ~IEEE80211_TX_UNICAST;
  		info->flags |= IEEE80211_TX_CTL_NO_ACK;
  	} else
  		tx->flags |= IEEE80211_TX_UNICAST;
  
  	if (!(info->flags & IEEE80211_TX_CTL_DONTFRAG)) {
  		if (!(tx->flags & IEEE80211_TX_UNICAST) ||
  		    skb->len + FCS_LEN <= local->hw.wiphy->frag_threshold ||
  		    info->flags & IEEE80211_TX_CTL_AMPDU)
  			info->flags |= IEEE80211_TX_CTL_DONTFRAG;
  	}
  
  	if (!tx->sta)
  		info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT;
  	else if (test_and_clear_sta_flag(tx->sta, WLAN_STA_CLEAR_PS_FILT)) {
  		info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT;
  		ieee80211_check_fast_xmit(tx->sta);
  	}
  
  	info->flags |= IEEE80211_TX_CTL_FIRST_FRAGMENT;
  
  	return TX_CONTINUE;
  }
  
  static struct txq_info *ieee80211_get_txq(struct ieee80211_local *local,
  					  struct ieee80211_vif *vif,
  					  struct sta_info *sta,
  					  struct sk_buff *skb)
  {
  	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  	struct ieee80211_txq *txq = NULL;
  
  	if ((info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM) ||
  	    (info->control.flags & IEEE80211_TX_CTRL_PS_RESPONSE))
  		return NULL;
  
  	if (!ieee80211_is_data(hdr->frame_control))
  		return NULL;
  
  	if (sta) {
  		u8 tid = skb->priority & IEEE80211_QOS_CTL_TID_MASK;
  
  		if (!sta->uploaded)
  			return NULL;
  
  		txq = sta->sta.txq[tid];
  	} else if (vif) {
  		txq = vif->txq;
  	}
  
  	if (!txq)
  		return NULL;
  
  	return to_txq_info(txq);
  }
  
  static void ieee80211_set_skb_enqueue_time(struct sk_buff *skb)
  {
  	IEEE80211_SKB_CB(skb)->control.enqueue_time = codel_get_time();
  }
  
  static u32 codel_skb_len_func(const struct sk_buff *skb)
  {
  	return skb->len;
  }
  
  static codel_time_t codel_skb_time_func(const struct sk_buff *skb)
  {
  	const struct ieee80211_tx_info *info;
  
  	info = (const struct ieee80211_tx_info *)skb->cb;
  	return info->control.enqueue_time;
  }
  
  static struct sk_buff *codel_dequeue_func(struct codel_vars *cvars,
  					  void *ctx)
  {
  	struct ieee80211_local *local;
  	struct txq_info *txqi;
  	struct fq *fq;
  	struct fq_flow *flow;
  
  	txqi = ctx;
  	local = vif_to_sdata(txqi->txq.vif)->local;
  	fq = &local->fq;
  
  	if (cvars == &txqi->def_cvars)
  		flow = &txqi->def_flow;
  	else
  		flow = &fq->flows[cvars - local->cvars];
  
  	return fq_flow_dequeue(fq, flow);
  }
  
  static void codel_drop_func(struct sk_buff *skb,
  			    void *ctx)
  {
  	struct ieee80211_local *local;
  	struct ieee80211_hw *hw;
  	struct txq_info *txqi;
  
  	txqi = ctx;
  	local = vif_to_sdata(txqi->txq.vif)->local;
  	hw = &local->hw;
  
  	ieee80211_free_txskb(hw, skb);
  }
  
  static struct sk_buff *fq_tin_dequeue_func(struct fq *fq,
  					   struct fq_tin *tin,
  					   struct fq_flow *flow)
  {
  	struct ieee80211_local *local;
  	struct txq_info *txqi;
  	struct codel_vars *cvars;
  	struct codel_params *cparams;
  	struct codel_stats *cstats;
  
  	local = container_of(fq, struct ieee80211_local, fq);
  	txqi = container_of(tin, struct txq_info, tin);
  	cstats = &txqi->cstats;
  
  	if (txqi->txq.sta) {
  		struct sta_info *sta = container_of(txqi->txq.sta,
  						    struct sta_info, sta);
  		cparams = &sta->cparams;
  	} else {
  		cparams = &local->cparams;
  	}
  
  	if (flow == &txqi->def_flow)
  		cvars = &txqi->def_cvars;
  	else
  		cvars = &local->cvars[flow - fq->flows];
  
  	return codel_dequeue(txqi,
  			     &flow->backlog,
  			     cparams,
  			     cvars,
  			     cstats,
  			     codel_skb_len_func,
  			     codel_skb_time_func,
  			     codel_drop_func,
  			     codel_dequeue_func);
  }
  
  static void fq_skb_free_func(struct fq *fq,
  			     struct fq_tin *tin,
  			     struct fq_flow *flow,
  			     struct sk_buff *skb)
  {
  	struct ieee80211_local *local;
  
  	local = container_of(fq, struct ieee80211_local, fq);
  	ieee80211_free_txskb(&local->hw, skb);
  }
  
  static struct fq_flow *fq_flow_get_default_func(struct fq *fq,
  						struct fq_tin *tin,
  						int idx,
  						struct sk_buff *skb)
  {
  	struct txq_info *txqi;
  
  	txqi = container_of(tin, struct txq_info, tin);
  	return &txqi->def_flow;
  }
  
  static void ieee80211_txq_enqueue(struct ieee80211_local *local,
  				  struct txq_info *txqi,
  				  struct sk_buff *skb)
  {
  	struct fq *fq = &local->fq;
  	struct fq_tin *tin = &txqi->tin;
  
  	ieee80211_set_skb_enqueue_time(skb);
  	fq_tin_enqueue(fq, tin, skb,
  		       fq_skb_free_func,
  		       fq_flow_get_default_func);
  }
  
  static bool fq_vlan_filter_func(struct fq *fq, struct fq_tin *tin,
  				struct fq_flow *flow, struct sk_buff *skb,
  				void *data)
  {
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  
  	return info->control.vif == data;
  }
  
  void ieee80211_txq_remove_vlan(struct ieee80211_local *local,
  			       struct ieee80211_sub_if_data *sdata)
  {
  	struct fq *fq = &local->fq;
  	struct txq_info *txqi;
  	struct fq_tin *tin;
  	struct ieee80211_sub_if_data *ap;
  
  	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP_VLAN))
  		return;
  
  	ap = container_of(sdata->bss, struct ieee80211_sub_if_data, u.ap);
  
  	if (!ap->vif.txq)
  		return;
  
  	txqi = to_txq_info(ap->vif.txq);
  	tin = &txqi->tin;
  
  	spin_lock_bh(&fq->lock);
  	fq_tin_filter(fq, tin, fq_vlan_filter_func, &sdata->vif,
  		      fq_skb_free_func);
  	spin_unlock_bh(&fq->lock);
  }
  
  void ieee80211_txq_init(struct ieee80211_sub_if_data *sdata,
  			struct sta_info *sta,
  			struct txq_info *txqi, int tid)
  {
  	fq_tin_init(&txqi->tin);
  	fq_flow_init(&txqi->def_flow);
  	codel_vars_init(&txqi->def_cvars);
  	codel_stats_init(&txqi->cstats);
  	__skb_queue_head_init(&txqi->frags);
  
  	txqi->txq.vif = &sdata->vif;
  
  	if (sta) {
  		txqi->txq.sta = &sta->sta;
  		sta->sta.txq[tid] = &txqi->txq;
  		txqi->txq.tid = tid;
  		txqi->txq.ac = ieee80211_ac_from_tid(tid);
  	} else {
  		sdata->vif.txq = &txqi->txq;
  		txqi->txq.tid = 0;
  		txqi->txq.ac = IEEE80211_AC_BE;
  	}
  }
  
  void ieee80211_txq_purge(struct ieee80211_local *local,
  			 struct txq_info *txqi)
  {
  	struct fq *fq = &local->fq;
  	struct fq_tin *tin = &txqi->tin;
  
  	fq_tin_reset(fq, tin, fq_skb_free_func);
  	ieee80211_purge_tx_queue(&local->hw, &txqi->frags);
  }
  
  void ieee80211_txq_set_params(struct ieee80211_local *local)
  {
  	if (local->hw.wiphy->txq_limit)
  		local->fq.limit = local->hw.wiphy->txq_limit;
  	else
  		local->hw.wiphy->txq_limit = local->fq.limit;
  
  	if (local->hw.wiphy->txq_memory_limit)
  		local->fq.memory_limit = local->hw.wiphy->txq_memory_limit;
  	else
  		local->hw.wiphy->txq_memory_limit = local->fq.memory_limit;
  
  	if (local->hw.wiphy->txq_quantum)
  		local->fq.quantum = local->hw.wiphy->txq_quantum;
  	else
  		local->hw.wiphy->txq_quantum = local->fq.quantum;
  }
  
  int ieee80211_txq_setup_flows(struct ieee80211_local *local)
  {
  	struct fq *fq = &local->fq;
  	int ret;
  	int i;
  	bool supp_vht = false;
  	enum nl80211_band band;
  
  	if (!local->ops->wake_tx_queue)
  		return 0;
  
  	ret = fq_init(fq, 4096);
  	if (ret)
  		return ret;
  
  	/*
  	 * If the hardware doesn't support VHT, it is safe to limit the maximum
  	 * queue size. 4 Mbytes is 64 max-size aggregates in 802.11n.
  	 */
  	for (band = 0; band < NUM_NL80211_BANDS; band++) {
  		struct ieee80211_supported_band *sband;
  
  		sband = local->hw.wiphy->bands[band];
  		if (!sband)
  			continue;
  
  		supp_vht = supp_vht || sband->vht_cap.vht_supported;
  	}
  
  	if (!supp_vht)
  		fq->memory_limit = 4 << 20; /* 4 Mbytes */
  
  	codel_params_init(&local->cparams);
  	local->cparams.interval = MS2TIME(100);
  	local->cparams.target = MS2TIME(20);
  	local->cparams.ecn = true;
  
  	local->cvars = kcalloc(fq->flows_cnt, sizeof(local->cvars[0]),
  			       GFP_KERNEL);
  	if (!local->cvars) {
  		spin_lock_bh(&fq->lock);
  		fq_reset(fq, fq_skb_free_func);
  		spin_unlock_bh(&fq->lock);
  		return -ENOMEM;
  	}
  
  	for (i = 0; i < fq->flows_cnt; i++)
  		codel_vars_init(&local->cvars[i]);
  
  	ieee80211_txq_set_params(local);
  
  	return 0;
  }
  
  void ieee80211_txq_teardown_flows(struct ieee80211_local *local)
  {
  	struct fq *fq = &local->fq;
  
  	if (!local->ops->wake_tx_queue)
  		return;
  
  	kfree(local->cvars);
  	local->cvars = NULL;
  
  	spin_lock_bh(&fq->lock);
  	fq_reset(fq, fq_skb_free_func);
  	spin_unlock_bh(&fq->lock);
  }
  
  static bool ieee80211_queue_skb(struct ieee80211_local *local,
  				struct ieee80211_sub_if_data *sdata,
  				struct sta_info *sta,
  				struct sk_buff *skb)
  {
  	struct fq *fq = &local->fq;
  	struct ieee80211_vif *vif;
  	struct txq_info *txqi;
  
  	if (!local->ops->wake_tx_queue ||
  	    sdata->vif.type == NL80211_IFTYPE_MONITOR)
  		return false;
  
  	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
  		sdata = container_of(sdata->bss,
  				     struct ieee80211_sub_if_data, u.ap);
  
  	vif = &sdata->vif;
  	txqi = ieee80211_get_txq(local, vif, sta, skb);
  
  	if (!txqi)
  		return false;
  
  	spin_lock_bh(&fq->lock);
  	ieee80211_txq_enqueue(local, txqi, skb);
  	spin_unlock_bh(&fq->lock);
  
  	drv_wake_tx_queue(local, txqi);
  
  	return true;
  }
  
  static bool ieee80211_tx_frags(struct ieee80211_local *local,
  			       struct ieee80211_vif *vif,
  			       struct ieee80211_sta *sta,
  			       struct sk_buff_head *skbs,
  			       bool txpending)
  {
  	struct ieee80211_tx_control control = {};
  	struct sk_buff *skb, *tmp;
  	unsigned long flags;
  
  	skb_queue_walk_safe(skbs, skb, tmp) {
  		struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  		int q = info->hw_queue;
  
  #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
  		if (WARN_ON_ONCE(q >= local->hw.queues)) {
  			__skb_unlink(skb, skbs);
  			ieee80211_free_txskb(&local->hw, skb);
  			continue;
  		}
  #endif
  
  		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
  		if (local->queue_stop_reasons[q] ||
  		    (!txpending && !skb_queue_empty(&local->pending[q]))) {
  			if (unlikely(info->flags &
  				     IEEE80211_TX_INTFL_OFFCHAN_TX_OK)) {
  				if (local->queue_stop_reasons[q] &
  				    ~BIT(IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL)) {
  					/*
  					 * Drop off-channel frames if queues
  					 * are stopped for any reason other
  					 * than off-channel operation. Never
  					 * queue them.
  					 */
  					spin_unlock_irqrestore(
  						&local->queue_stop_reason_lock,
  						flags);
  					ieee80211_purge_tx_queue(&local->hw,
  								 skbs);
  					return true;
  				}
  			} else {
  
  				/*
  				 * Since queue is stopped, queue up frames for
  				 * later transmission from the tx-pending
  				 * tasklet when the queue is woken again.
  				 */
  				if (txpending)
  					skb_queue_splice_init(skbs,
  							      &local->pending[q]);
  				else
  					skb_queue_splice_tail_init(skbs,
  								   &local->pending[q]);
  
  				spin_unlock_irqrestore(&local->queue_stop_reason_lock,
  						       flags);
  				return false;
  			}
  		}
  		spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
  
  		info->control.vif = vif;
  		control.sta = sta;
  
  		__skb_unlink(skb, skbs);
  		drv_tx(local, &control, skb);
  	}
  
  	return true;
  }
  
  /*
   * Returns false if the frame couldn't be transmitted but was queued instead.
   */
  static bool __ieee80211_tx(struct ieee80211_local *local,
  			   struct sk_buff_head *skbs, int led_len,
  			   struct sta_info *sta, bool txpending)
  {
  	struct ieee80211_tx_info *info;
  	struct ieee80211_sub_if_data *sdata;
  	struct ieee80211_vif *vif;
  	struct ieee80211_sta *pubsta;
  	struct sk_buff *skb;
  	bool result = true;
  	__le16 fc;
  
  	if (WARN_ON(skb_queue_empty(skbs)))
  		return true;
  
  	skb = skb_peek(skbs);
  	fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
  	info = IEEE80211_SKB_CB(skb);
  	sdata = vif_to_sdata(info->control.vif);
  	if (sta && !sta->uploaded)
  		sta = NULL;
  
  	if (sta)
  		pubsta = &sta->sta;
  	else
  		pubsta = NULL;
  
  	switch (sdata->vif.type) {
  	case NL80211_IFTYPE_MONITOR:
  		if (sdata->u.mntr.flags & MONITOR_FLAG_ACTIVE) {
  			vif = &sdata->vif;
  			break;
  		}
  		sdata = rcu_dereference(local->monitor_sdata);
  		if (sdata) {
  			vif = &sdata->vif;
  			info->hw_queue =
  				vif->hw_queue[skb_get_queue_mapping(skb)];
  		} else if (ieee80211_hw_check(&local->hw, QUEUE_CONTROL)) {
  			ieee80211_purge_tx_queue(&local->hw, skbs);
  			return true;
  		} else
  			vif = NULL;
  		break;
  	case NL80211_IFTYPE_AP_VLAN:
  		sdata = container_of(sdata->bss,
  				     struct ieee80211_sub_if_data, u.ap);
  		/* fall through */
  	default:
  		vif = &sdata->vif;
  		break;
  	}
  
  	result = ieee80211_tx_frags(local, vif, pubsta, skbs,
  				    txpending);
  
  	ieee80211_tpt_led_trig_tx(local, fc, led_len);
  
  	WARN_ON_ONCE(!skb_queue_empty(skbs));
  
  	return result;
  }
  
  /*
   * Invoke TX handlers, return 0 on success and non-zero if the
   * frame was dropped or queued.
   *
   * The handlers are split into an early and late part. The latter is everything
   * that can be sensitive to reordering, and will be deferred to after packets
   * are dequeued from the intermediate queues (when they are enabled).
   */
  static int invoke_tx_handlers_early(struct ieee80211_tx_data *tx)
  {
  	ieee80211_tx_result res = TX_DROP;
  
  #define CALL_TXH(txh) \
  	do {				\
  		res = txh(tx);		\
  		if (res != TX_CONTINUE)	\
  			goto txh_done;	\
  	} while (0)
  
  	CALL_TXH(ieee80211_tx_h_dynamic_ps);
  	CALL_TXH(ieee80211_tx_h_check_assoc);
  	CALL_TXH(ieee80211_tx_h_ps_buf);
  	CALL_TXH(ieee80211_tx_h_check_control_port_protocol);
  	CALL_TXH(ieee80211_tx_h_select_key);
  	if (!ieee80211_hw_check(&tx->local->hw, HAS_RATE_CONTROL))
  		CALL_TXH(ieee80211_tx_h_rate_ctrl);
  
   txh_done:
  	if (unlikely(res == TX_DROP)) {
  		I802_DEBUG_INC(tx->local->tx_handlers_drop);
  		if (tx->skb)
  			ieee80211_free_txskb(&tx->local->hw, tx->skb);
  		else
  			ieee80211_purge_tx_queue(&tx->local->hw, &tx->skbs);
  		return -1;
  	} else if (unlikely(res == TX_QUEUED)) {
  		I802_DEBUG_INC(tx->local->tx_handlers_queued);
  		return -1;
  	}
  
  	return 0;
  }
  
  /*
   * Late handlers can be called while the sta lock is held. Handlers that can
   * cause packets to be generated will cause deadlock!
   */
  static int invoke_tx_handlers_late(struct ieee80211_tx_data *tx)
  {
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
  	ieee80211_tx_result res = TX_CONTINUE;
  
  	if (unlikely(info->flags & IEEE80211_TX_INTFL_RETRANSMISSION)) {
  		__skb_queue_tail(&tx->skbs, tx->skb);
  		tx->skb = NULL;
  		goto txh_done;
  	}
  
  	CALL_TXH(ieee80211_tx_h_michael_mic_add);
  	CALL_TXH(ieee80211_tx_h_sequence);
  	CALL_TXH(ieee80211_tx_h_fragment);
  	/* handlers after fragment must be aware of tx info fragmentation! */
  	CALL_TXH(ieee80211_tx_h_stats);
  	CALL_TXH(ieee80211_tx_h_encrypt);
  	if (!ieee80211_hw_check(&tx->local->hw, HAS_RATE_CONTROL))
  		CALL_TXH(ieee80211_tx_h_calculate_duration);
  #undef CALL_TXH
  
   txh_done:
  	if (unlikely(res == TX_DROP)) {
  		I802_DEBUG_INC(tx->local->tx_handlers_drop);
  		if (tx->skb)
  			ieee80211_free_txskb(&tx->local->hw, tx->skb);
  		else
  			ieee80211_purge_tx_queue(&tx->local->hw, &tx->skbs);
  		return -1;
  	} else if (unlikely(res == TX_QUEUED)) {
  		I802_DEBUG_INC(tx->local->tx_handlers_queued);
  		return -1;
  	}
  
  	return 0;
  }
  
  static int invoke_tx_handlers(struct ieee80211_tx_data *tx)
  {
  	int r = invoke_tx_handlers_early(tx);
  
  	if (r)
  		return r;
  	return invoke_tx_handlers_late(tx);
  }
  
  bool ieee80211_tx_prepare_skb(struct ieee80211_hw *hw,
  			      struct ieee80211_vif *vif, struct sk_buff *skb,
  			      int band, struct ieee80211_sta **sta)
  {
  	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  	struct ieee80211_tx_data tx;
  	struct sk_buff *skb2;
  
  	if (ieee80211_tx_prepare(sdata, &tx, NULL, skb) == TX_DROP)
  		return false;
  
  	info->band = band;
  	info->control.vif = vif;
  	info->hw_queue = vif->hw_queue[skb_get_queue_mapping(skb)];
  
  	if (invoke_tx_handlers(&tx))
  		return false;
  
  	if (sta) {
  		if (tx.sta)
  			*sta = &tx.sta->sta;
  		else
  			*sta = NULL;
  	}
  
  	/* this function isn't suitable for fragmented data frames */
  	skb2 = __skb_dequeue(&tx.skbs);
  	if (WARN_ON(skb2 != skb || !skb_queue_empty(&tx.skbs))) {
  		ieee80211_free_txskb(hw, skb2);
  		ieee80211_purge_tx_queue(hw, &tx.skbs);
  		return false;
  	}
  
  	return true;
  }
  EXPORT_SYMBOL(ieee80211_tx_prepare_skb);
  
  /*
   * Returns false if the frame couldn't be transmitted but was queued instead.
   */
  static bool ieee80211_tx(struct ieee80211_sub_if_data *sdata,
  			 struct sta_info *sta, struct sk_buff *skb,
  			 bool txpending)
  {
  	struct ieee80211_local *local = sdata->local;
  	struct ieee80211_tx_data tx;
  	ieee80211_tx_result res_prepare;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  	bool result = true;
  	int led_len;
  
  	if (unlikely(skb->len < 10)) {
  		dev_kfree_skb(skb);
  		return true;
  	}
  
  	/* initialises tx */
  	led_len = skb->len;
  	res_prepare = ieee80211_tx_prepare(sdata, &tx, sta, skb);
  
  	if (unlikely(res_prepare == TX_DROP)) {
  		ieee80211_free_txskb(&local->hw, skb);
  		return true;
  	} else if (unlikely(res_prepare == TX_QUEUED)) {
  		return true;
  	}
  
  	/* set up hw_queue value early */
  	if (!(info->flags & IEEE80211_TX_CTL_TX_OFFCHAN) ||
  	    !ieee80211_hw_check(&local->hw, QUEUE_CONTROL))
  		info->hw_queue =
  			sdata->vif.hw_queue[skb_get_queue_mapping(skb)];
  
  	if (invoke_tx_handlers_early(&tx))
  		return false;
  
  	if (ieee80211_queue_skb(local, sdata, tx.sta, tx.skb))
  		return true;
  
  	if (!invoke_tx_handlers_late(&tx))
  		result = __ieee80211_tx(local, &tx.skbs, led_len,
  					tx.sta, txpending);
  
  	return result;
  }
  
  /* device xmit handlers */
  
  static int ieee80211_skb_resize(struct ieee80211_sub_if_data *sdata,
  				struct sk_buff *skb,
  				int head_need, bool may_encrypt)
  {
  	struct ieee80211_local *local = sdata->local;
  	int tail_need = 0;
  
  	if (may_encrypt && sdata->crypto_tx_tailroom_needed_cnt) {
  		tail_need = IEEE80211_ENCRYPT_TAILROOM;
  		tail_need -= skb_tailroom(skb);
  		tail_need = max_t(int, tail_need, 0);
  	}
  
  	if (skb_cloned(skb) &&
  	    (!ieee80211_hw_check(&local->hw, SUPPORTS_CLONED_SKBS) ||
  	     !skb_clone_writable(skb, ETH_HLEN) ||
  	     (may_encrypt && sdata->crypto_tx_tailroom_needed_cnt)))
  		I802_DEBUG_INC(local->tx_expand_skb_head_cloned);
  	else if (head_need || tail_need)
  		I802_DEBUG_INC(local->tx_expand_skb_head);
  	else
  		return 0;
  
  	if (pskb_expand_head(skb, head_need, tail_need, GFP_ATOMIC)) {
  		wiphy_debug(local->hw.wiphy,
  			    "failed to reallocate TX buffer\n");
  		return -ENOMEM;
  	}
  
  	return 0;
  }
  
  void ieee80211_xmit(struct ieee80211_sub_if_data *sdata,
  		    struct sta_info *sta, struct sk_buff *skb)
  {
  	struct ieee80211_local *local = sdata->local;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  	struct ieee80211_hdr *hdr;
  	int headroom;
  	bool may_encrypt;
  
  	may_encrypt = !(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT);
  
  	headroom = local->tx_headroom;
  	if (may_encrypt)
  		headroom += sdata->encrypt_headroom;
  	headroom -= skb_headroom(skb);
  	headroom = max_t(int, 0, headroom);
  
  	if (ieee80211_skb_resize(sdata, skb, headroom, may_encrypt)) {
  		ieee80211_free_txskb(&local->hw, skb);
  		return;
  	}
  
  	hdr = (struct ieee80211_hdr *) skb->data;
  	info->control.vif = &sdata->vif;
  
  	if (ieee80211_vif_is_mesh(&sdata->vif)) {
  		if (ieee80211_is_data(hdr->frame_control) &&
  		    is_unicast_ether_addr(hdr->addr1)) {
  			if (mesh_nexthop_resolve(sdata, skb))
  				return; /* skb queued: don't free */
  		} else {
  			ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
  		}
  	}
  
  	ieee80211_set_qos_hdr(sdata, skb);
  	ieee80211_tx(sdata, sta, skb, false);
  }
  
  static bool ieee80211_parse_tx_radiotap(struct ieee80211_local *local,
  					struct sk_buff *skb)
  {
  	struct ieee80211_radiotap_iterator iterator;
  	struct ieee80211_radiotap_header *rthdr =
  		(struct ieee80211_radiotap_header *) skb->data;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  	struct ieee80211_supported_band *sband =
  		local->hw.wiphy->bands[info->band];
  	int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len,
  						   NULL);
  	u16 txflags;
  	u16 rate = 0;
  	bool rate_found = false;
  	u8 rate_retries = 0;
  	u16 rate_flags = 0;
  	u8 mcs_known, mcs_flags, mcs_bw;
  	u16 vht_known;
  	u8 vht_mcs = 0, vht_nss = 0;
  	int i;
  
  	info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT |
  		       IEEE80211_TX_CTL_DONTFRAG;
  
  	/*
  	 * for every radiotap entry that is present
  	 * (ieee80211_radiotap_iterator_next returns -ENOENT when no more
  	 * entries present, or -EINVAL on error)
  	 */
  
  	while (!ret) {
  		ret = ieee80211_radiotap_iterator_next(&iterator);
  
  		if (ret)
  			continue;
  
  		/* see if this argument is something we can use */
  		switch (iterator.this_arg_index) {
  		/*
  		 * You must take care when dereferencing iterator.this_arg
  		 * for multibyte types... the pointer is not aligned.  Use
  		 * get_unaligned((type *)iterator.this_arg) to dereference
  		 * iterator.this_arg for type "type" safely on all arches.
  		*/
  		case IEEE80211_RADIOTAP_FLAGS:
  			if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FCS) {
  				/*
  				 * this indicates that the skb we have been
  				 * handed has the 32-bit FCS CRC at the end...
  				 * we should react to that by snipping it off
  				 * because it will be recomputed and added
  				 * on transmission
  				 */
  				if (skb->len < (iterator._max_length + FCS_LEN))
  					return false;
  
  				skb_trim(skb, skb->len - FCS_LEN);
  			}
  			if (*iterator.this_arg & IEEE80211_RADIOTAP_F_WEP)
  				info->flags &= ~IEEE80211_TX_INTFL_DONT_ENCRYPT;
  			if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FRAG)
  				info->flags &= ~IEEE80211_TX_CTL_DONTFRAG;
  			break;
  
  		case IEEE80211_RADIOTAP_TX_FLAGS:
  			txflags = get_unaligned_le16(iterator.this_arg);
  			if (txflags & IEEE80211_RADIOTAP_F_TX_NOACK)
  				info->flags |= IEEE80211_TX_CTL_NO_ACK;
  			break;
  
  		case IEEE80211_RADIOTAP_RATE:
  			rate = *iterator.this_arg;
  			rate_flags = 0;
  			rate_found = true;
  			break;
  
  		case IEEE80211_RADIOTAP_DATA_RETRIES:
  			rate_retries = *iterator.this_arg;
  			break;
  
  		case IEEE80211_RADIOTAP_MCS:
  			mcs_known = iterator.this_arg[0];
  			mcs_flags = iterator.this_arg[1];
  			if (!(mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_MCS))
  				break;
  
  			rate_found = true;
  			rate = iterator.this_arg[2];
  			rate_flags = IEEE80211_TX_RC_MCS;
  
  			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_GI &&
  			    mcs_flags & IEEE80211_RADIOTAP_MCS_SGI)
  				rate_flags |= IEEE80211_TX_RC_SHORT_GI;
  
  			mcs_bw = mcs_flags & IEEE80211_RADIOTAP_MCS_BW_MASK;
  			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_BW &&
  			    mcs_bw == IEEE80211_RADIOTAP_MCS_BW_40)
  				rate_flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
  			break;
  
  		case IEEE80211_RADIOTAP_VHT:
  			vht_known = get_unaligned_le16(iterator.this_arg);
  			rate_found = true;
  
  			rate_flags = IEEE80211_TX_RC_VHT_MCS;
  			if ((vht_known & IEEE80211_RADIOTAP_VHT_KNOWN_GI) &&
  			    (iterator.this_arg[2] &
  			     IEEE80211_RADIOTAP_VHT_FLAG_SGI))
  				rate_flags |= IEEE80211_TX_RC_SHORT_GI;
  			if (vht_known &
  			    IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH) {
  				if (iterator.this_arg[3] == 1)
  					rate_flags |=
  						IEEE80211_TX_RC_40_MHZ_WIDTH;
  				else if (iterator.this_arg[3] == 4)
  					rate_flags |=
  						IEEE80211_TX_RC_80_MHZ_WIDTH;
  				else if (iterator.this_arg[3] == 11)
  					rate_flags |=
  						IEEE80211_TX_RC_160_MHZ_WIDTH;
  			}
  
  			vht_mcs = iterator.this_arg[4] >> 4;
  			vht_nss = iterator.this_arg[4] & 0xF;
  			break;
  
  		/*
  		 * Please update the file
  		 * Documentation/networking/mac80211-injection.txt
  		 * when parsing new fields here.
  		 */
  
  		default:
  			break;
  		}
  	}
  
  	if (ret != -ENOENT) /* ie, if we didn't simply run out of fields */
  		return false;
  
  	if (rate_found) {
  		info->control.flags |= IEEE80211_TX_CTRL_RATE_INJECT;
  
  		for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
  			info->control.rates[i].idx = -1;
  			info->control.rates[i].flags = 0;
  			info->control.rates[i].count = 0;
  		}
  
  		if (rate_flags & IEEE80211_TX_RC_MCS) {
  			info->control.rates[0].idx = rate;
  		} else if (rate_flags & IEEE80211_TX_RC_VHT_MCS) {
  			ieee80211_rate_set_vht(info->control.rates, vht_mcs,
  					       vht_nss);
  		} else {
  			for (i = 0; i < sband->n_bitrates; i++) {
  				if (rate * 5 != sband->bitrates[i].bitrate)
  					continue;
  
  				info->control.rates[0].idx = i;
  				break;
  			}
  		}
  
  		if (info->control.rates[0].idx < 0)
  			info->control.flags &= ~IEEE80211_TX_CTRL_RATE_INJECT;
  
  		info->control.rates[0].flags = rate_flags;
  		info->control.rates[0].count = min_t(u8, rate_retries + 1,
  						     local->hw.max_rate_tries);
  	}
  
  	/*
  	 * remove the radiotap header
  	 * iterator->_max_length was sanity-checked against
  	 * skb->len by iterator init
  	 */
  	skb_pull(skb, iterator._max_length);
  
  	return true;
  }
  
  netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
  					 struct net_device *dev)
  {
  	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
  	struct ieee80211_chanctx_conf *chanctx_conf;
  	struct ieee80211_radiotap_header *prthdr =
  		(struct ieee80211_radiotap_header *)skb->data;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  	struct ieee80211_hdr *hdr;
  	struct ieee80211_sub_if_data *tmp_sdata, *sdata;
  	struct cfg80211_chan_def *chandef;
  	u16 len_rthdr;
  	int hdrlen;
  
  	/* check for not even having the fixed radiotap header part */
  	if (unlikely(skb->len < sizeof(struct ieee80211_radiotap_header)))
  		goto fail; /* too short to be possibly valid */
  
  	/* is it a header version we can trust to find length from? */
  	if (unlikely(prthdr->it_version))
  		goto fail; /* only version 0 is supported */
  
  	/* then there must be a radiotap header with a length we can use */
  	len_rthdr = ieee80211_get_radiotap_len(skb->data);
  
  	/* does the skb contain enough to deliver on the alleged length? */
  	if (unlikely(skb->len < len_rthdr))
  		goto fail; /* skb too short for claimed rt header extent */
  
  	/*
  	 * fix up the pointers accounting for the radiotap
  	 * header still being in there.  We are being given
  	 * a precooked IEEE80211 header so no need for
  	 * normal processing
  	 */
  	skb_set_mac_header(skb, len_rthdr);
  	/*
  	 * these are just fixed to the end of the rt area since we
  	 * don't have any better information and at this point, nobody cares
  	 */
  	skb_set_network_header(skb, len_rthdr);
  	skb_set_transport_header(skb, len_rthdr);
  
  	if (skb->len < len_rthdr + 2)
  		goto fail;
  
  	hdr = (struct ieee80211_hdr *)(skb->data + len_rthdr);
  	hdrlen = ieee80211_hdrlen(hdr->frame_control);
  
  	if (skb->len < len_rthdr + hdrlen)
  		goto fail;
  
  	/*
  	 * Initialize skb->protocol if the injected frame is a data frame
  	 * carrying a rfc1042 header
  	 */
  	if (ieee80211_is_data(hdr->frame_control) &&
  	    skb->len >= len_rthdr + hdrlen + sizeof(rfc1042_header) + 2) {
  		u8 *payload = (u8 *)hdr + hdrlen;
  
  		if (ether_addr_equal(payload, rfc1042_header))
  			skb->protocol = cpu_to_be16((payload[6] << 8) |
  						    payload[7]);
  	}
  
  	memset(info, 0, sizeof(*info));
  
  	info->flags = IEEE80211_TX_CTL_REQ_TX_STATUS |
  		      IEEE80211_TX_CTL_INJECTED;
  
  	rcu_read_lock();
  
  	/*
  	 * We process outgoing injected frames that have a local address
  	 * we handle as though they are non-injected frames.
  	 * This code here isn't entirely correct, the local MAC address
  	 * isn't always enough to find the interface to use; for proper
  	 * VLAN/WDS support we will need a different mechanism (which
  	 * likely isn't going to be monitor interfaces).
  	 */
  	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
  
  	list_for_each_entry_rcu(tmp_sdata, &local->interfaces, list) {
  		if (!ieee80211_sdata_running(tmp_sdata))
  			continue;
  		if (tmp_sdata->vif.type == NL80211_IFTYPE_MONITOR ||
  		    tmp_sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
  		    tmp_sdata->vif.type == NL80211_IFTYPE_WDS)
  			continue;
  		if (ether_addr_equal(tmp_sdata->vif.addr, hdr->addr2)) {
  			sdata = tmp_sdata;
  			break;
  		}
  	}
  
  	chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  	if (!chanctx_conf) {
  		tmp_sdata = rcu_dereference(local->monitor_sdata);
  		if (tmp_sdata)
  			chanctx_conf =
  				rcu_dereference(tmp_sdata->vif.chanctx_conf);
  	}
  
  	if (chanctx_conf)
  		chandef = &chanctx_conf->def;
  	else if (!local->use_chanctx)
  		chandef = &local->_oper_chandef;
  	else
  		goto fail_rcu;
  
  	/*
  	 * Frame injection is not allowed if beaconing is not allowed
  	 * or if we need radar detection. Beaconing is usually not allowed when
  	 * the mode or operation (Adhoc, AP, Mesh) does not support DFS.
  	 * Passive scan is also used in world regulatory domains where
  	 * your country is not known and as such it should be treated as
  	 * NO TX unless the channel is explicitly allowed in which case
  	 * your current regulatory domain would not have the passive scan
  	 * flag.
  	 *
  	 * Since AP mode uses monitor interfaces to inject/TX management
  	 * frames we can make AP mode the exception to this rule once it
  	 * supports radar detection as its implementation can deal with
  	 * radar detection by itself. We can do that later by adding a
  	 * monitor flag interfaces used for AP support.
  	 */
  	if (!cfg80211_reg_can_beacon(local->hw.wiphy, chandef,
  				     sdata->vif.type))
  		goto fail_rcu;
  
  	info->band = chandef->chan->band;
  
  	/* process and remove the injection radiotap header */
  	if (!ieee80211_parse_tx_radiotap(local, skb))
  		goto fail_rcu;
  
  	ieee80211_xmit(sdata, NULL, skb);
  	rcu_read_unlock();
  
  	return NETDEV_TX_OK;
  
  fail_rcu:
  	rcu_read_unlock();
  fail:
  	dev_kfree_skb(skb);
  	return NETDEV_TX_OK; /* meaning, we dealt with the skb */
  }
  
  static inline bool ieee80211_is_tdls_setup(struct sk_buff *skb)
  {
  	u16 ethertype = (skb->data[12] << 8) | skb->data[13];
  
  	return ethertype == ETH_P_TDLS &&
  	       skb->len > 14 &&
  	       skb->data[14] == WLAN_TDLS_SNAP_RFTYPE;
  }
  
  static int ieee80211_lookup_ra_sta(struct ieee80211_sub_if_data *sdata,
  				   struct sk_buff *skb,
  				   struct sta_info **sta_out)
  {
  	struct sta_info *sta;
  
  	switch (sdata->vif.type) {
  	case NL80211_IFTYPE_AP_VLAN:
  		sta = rcu_dereference(sdata->u.vlan.sta);
  		if (sta) {
  			*sta_out = sta;
  			return 0;
  		} else if (sdata->wdev.use_4addr) {
  			return -ENOLINK;
  		}
  		/* fall through */
  	case NL80211_IFTYPE_AP:
  	case NL80211_IFTYPE_OCB:
  	case NL80211_IFTYPE_ADHOC:
  		if (is_multicast_ether_addr(skb->data)) {
  			*sta_out = ERR_PTR(-ENOENT);
  			return 0;
  		}
  		sta = sta_info_get_bss(sdata, skb->data);
  		break;
  	case NL80211_IFTYPE_WDS:
  		sta = sta_info_get(sdata, sdata->u.wds.remote_addr);
  		break;
  #ifdef CONFIG_MAC80211_MESH
  	case NL80211_IFTYPE_MESH_POINT:
  		/* determined much later */
  		*sta_out = NULL;
  		return 0;
  #endif
  	case NL80211_IFTYPE_STATION:
  		if (sdata->wdev.wiphy->flags & WIPHY_FLAG_SUPPORTS_TDLS) {
  			sta = sta_info_get(sdata, skb->data);
  			if (sta && test_sta_flag(sta, WLAN_STA_TDLS_PEER)) {
  				if (test_sta_flag(sta,
  						  WLAN_STA_TDLS_PEER_AUTH)) {
  					*sta_out = sta;
  					return 0;
  				}
  
  				/*
  				 * TDLS link during setup - throw out frames to
  				 * peer. Allow TDLS-setup frames to unauthorized
  				 * peers for the special case of a link teardown
  				 * after a TDLS sta is removed due to being
  				 * unreachable.
  				 */
  				if (!ieee80211_is_tdls_setup(skb))
  					return -EINVAL;
  			}
  
  		}
  
  		sta = sta_info_get(sdata, sdata->u.mgd.bssid);
  		if (!sta)
  			return -ENOLINK;
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	*sta_out = sta ?: ERR_PTR(-ENOENT);
  	return 0;
  }
  
  /**
   * ieee80211_build_hdr - build 802.11 header in the given frame
   * @sdata: virtual interface to build the header for
   * @skb: the skb to build the header in
   * @info_flags: skb flags to set
   *
   * This function takes the skb with 802.3 header and reformats the header to
   * the appropriate IEEE 802.11 header based on which interface the packet is
   * being transmitted on.
   *
   * Note that this function also takes care of the TX status request and
   * potential unsharing of the SKB - this needs to be interleaved with the
   * header building.
   *
   * The function requires the read-side RCU lock held
   *
   * Returns: the (possibly reallocated) skb or an ERR_PTR() code
   */
  static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata,
  					   struct sk_buff *skb, u32 info_flags,
  					   struct sta_info *sta)
  {
  	struct ieee80211_local *local = sdata->local;
  	struct ieee80211_tx_info *info;
  	int head_need;
  	u16 ethertype, hdrlen,  meshhdrlen = 0;
  	__le16 fc;
  	struct ieee80211_hdr hdr;
  	struct ieee80211s_hdr mesh_hdr __maybe_unused;
  	struct mesh_path __maybe_unused *mppath = NULL, *mpath = NULL;
  	const u8 *encaps_data;
  	int encaps_len, skip_header_bytes;
  	bool wme_sta = false, authorized = false;
  	bool tdls_peer;
  	bool multicast;
  	u16 info_id = 0;
  	struct ieee80211_chanctx_conf *chanctx_conf;
  	struct ieee80211_sub_if_data *ap_sdata;
  	enum nl80211_band band;
  	int ret;
  
  	if (IS_ERR(sta))
  		sta = NULL;
  
  	/* convert Ethernet header to proper 802.11 header (based on
  	 * operation mode) */
  	ethertype = (skb->data[12] << 8) | skb->data[13];
  	fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA);
  
  	switch (sdata->vif.type) {
  	case NL80211_IFTYPE_AP_VLAN:
  		if (sdata->wdev.use_4addr) {
  			fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
  			/* RA TA DA SA */
  			memcpy(hdr.addr1, sta->sta.addr, ETH_ALEN);
  			memcpy(hdr.addr2, sdata->vif.addr, ETH_ALEN);
  			memcpy(hdr.addr3, skb->data, ETH_ALEN);
  			memcpy(hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
  			hdrlen = 30;
  			authorized = test_sta_flag(sta, WLAN_STA_AUTHORIZED);
  			wme_sta = sta->sta.wme;
  		}
  		ap_sdata = container_of(sdata->bss, struct ieee80211_sub_if_data,
  					u.ap);
  		chanctx_conf = rcu_dereference(ap_sdata->vif.chanctx_conf);
  		if (!chanctx_conf) {
  			ret = -ENOTCONN;
  			goto free;
  		}
  		band = chanctx_conf->def.chan->band;
  		if (sdata->wdev.use_4addr)
  			break;
  		/* fall through */
  	case NL80211_IFTYPE_AP:
  		if (sdata->vif.type == NL80211_IFTYPE_AP)
  			chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  		if (!chanctx_conf) {
  			ret = -ENOTCONN;
  			goto free;
  		}
  		fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS);
  		/* DA BSSID SA */
  		memcpy(hdr.addr1, skb->data, ETH_ALEN);
  		memcpy(hdr.addr2, sdata->vif.addr, ETH_ALEN);
  		memcpy(hdr.addr3, skb->data + ETH_ALEN, ETH_ALEN);
  		hdrlen = 24;
  		band = chanctx_conf->def.chan->band;
  		break;
  	case NL80211_IFTYPE_WDS:
  		fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
  		/* RA TA DA SA */
  		memcpy(hdr.addr1, sdata->u.wds.remote_addr, ETH_ALEN);
  		memcpy(hdr.addr2, sdata->vif.addr, ETH_ALEN);
  		memcpy(hdr.addr3, skb->data, ETH_ALEN);
  		memcpy(hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
  		hdrlen = 30;
  		/*
  		 * This is the exception! WDS style interfaces are prohibited
  		 * when channel contexts are in used so this must be valid
  		 */
  		band = local->hw.conf.chandef.chan->band;
  		break;
  #ifdef CONFIG_MAC80211_MESH
  	case NL80211_IFTYPE_MESH_POINT:
  		if (!is_multicast_ether_addr(skb->data)) {
  			struct sta_info *next_hop;
  			bool mpp_lookup = true;
  
  			mpath = mesh_path_lookup(sdata, skb->data);
  			if (mpath) {
  				mpp_lookup = false;
  				next_hop = rcu_dereference(mpath->next_hop);
  				if (!next_hop ||
  				    !(mpath->flags & (MESH_PATH_ACTIVE |
  						      MESH_PATH_RESOLVING)))
  					mpp_lookup = true;
  			}
  
  			if (mpp_lookup) {
  				mppath = mpp_path_lookup(sdata, skb->data);
  				if (mppath)
  					mppath->exp_time = jiffies;
  			}
  
  			if (mppath && mpath)
  				mesh_path_del(sdata, mpath->dst);
  		}
  
  		/*
  		 * Use address extension if it is a packet from
  		 * another interface or if we know the destination
  		 * is being proxied by a portal (i.e. portal address
  		 * differs from proxied address)
  		 */
  		if (ether_addr_equal(sdata->vif.addr, skb->data + ETH_ALEN) &&
  		    !(mppath && !ether_addr_equal(mppath->mpp, skb->data))) {
  			hdrlen = ieee80211_fill_mesh_addresses(&hdr, &fc,
  					skb->data, skb->data + ETH_ALEN);
  			meshhdrlen = ieee80211_new_mesh_header(sdata, &mesh_hdr,
  							       NULL, NULL);
  		} else {
  			/* DS -> MBSS (802.11-2012 13.11.3.3).
  			 * For unicast with unknown forwarding information,
  			 * destination might be in the MBSS or if that fails
  			 * forwarded to another mesh gate. In either case
  			 * resolution will be handled in ieee80211_xmit(), so
  			 * leave the original DA. This also works for mcast */
  			const u8 *mesh_da = skb->data;
  
  			if (mppath)
  				mesh_da = mppath->mpp;
  			else if (mpath)
  				mesh_da = mpath->dst;
  
  			hdrlen = ieee80211_fill_mesh_addresses(&hdr, &fc,
  					mesh_da, sdata->vif.addr);
  			if (is_multicast_ether_addr(mesh_da))
  				/* DA TA mSA AE:SA */
  				meshhdrlen = ieee80211_new_mesh_header(
  						sdata, &mesh_hdr,
  						skb->data + ETH_ALEN, NULL);
  			else
  				/* RA TA mDA mSA AE:DA SA */
  				meshhdrlen = ieee80211_new_mesh_header(
  						sdata, &mesh_hdr, skb->data,
  						skb->data + ETH_ALEN);
  
  		}
  		chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  		if (!chanctx_conf) {
  			ret = -ENOTCONN;
  			goto free;
  		}
  		band = chanctx_conf->def.chan->band;
  		break;
  #endif
  	case NL80211_IFTYPE_STATION:
  		/* we already did checks when looking up the RA STA */
  		tdls_peer = test_sta_flag(sta, WLAN_STA_TDLS_PEER);
  
  		if (tdls_peer) {
  			/* DA SA BSSID */
  			memcpy(hdr.addr1, skb->data, ETH_ALEN);
  			memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
  			memcpy(hdr.addr3, sdata->u.mgd.bssid, ETH_ALEN);
  			hdrlen = 24;
  		}  else if (sdata->u.mgd.use_4addr &&
  			    cpu_to_be16(ethertype) != sdata->control_port_protocol) {
  			fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS |
  					  IEEE80211_FCTL_TODS);
  			/* RA TA DA SA */
  			memcpy(hdr.addr1, sdata->u.mgd.bssid, ETH_ALEN);
  			memcpy(hdr.addr2, sdata->vif.addr, ETH_ALEN);
  			memcpy(hdr.addr3, skb->data, ETH_ALEN);
  			memcpy(hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
  			hdrlen = 30;
  		} else {
  			fc |= cpu_to_le16(IEEE80211_FCTL_TODS);
  			/* BSSID SA DA */
  			memcpy(hdr.addr1, sdata->u.mgd.bssid, ETH_ALEN);
  			memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
  			memcpy(hdr.addr3, skb->data, ETH_ALEN);
  			hdrlen = 24;
  		}
  		chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  		if (!chanctx_conf) {
  			ret = -ENOTCONN;
  			goto free;
  		}
  		band = chanctx_conf->def.chan->band;
  		break;
  	case NL80211_IFTYPE_OCB:
  		/* DA SA BSSID */
  		memcpy(hdr.addr1, skb->data, ETH_ALEN);
  		memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
  		eth_broadcast_addr(hdr.addr3);
  		hdrlen = 24;
  		chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  		if (!chanctx_conf) {
  			ret = -ENOTCONN;
  			goto free;
  		}
  		band = chanctx_conf->def.chan->band;
  		break;
  	case NL80211_IFTYPE_ADHOC:
  		/* DA SA BSSID */
  		memcpy(hdr.addr1, skb->data, ETH_ALEN);
  		memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
  		memcpy(hdr.addr3, sdata->u.ibss.bssid, ETH_ALEN);
  		hdrlen = 24;
  		chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  		if (!chanctx_conf) {
  			ret = -ENOTCONN;
  			goto free;
  		}
  		band = chanctx_conf->def.chan->band;
  		break;
  	default:
  		ret = -EINVAL;
  		goto free;
  	}
  
  	multicast = is_multicast_ether_addr(hdr.addr1);
  
  	/* sta is always NULL for mesh */
  	if (sta) {
  		authorized = test_sta_flag(sta, WLAN_STA_AUTHORIZED);
  		wme_sta = sta->sta.wme;
  	} else if (ieee80211_vif_is_mesh(&sdata->vif)) {
  		/* For mesh, the use of the QoS header is mandatory */
  		wme_sta = true;
  	}
  
  	/* receiver does QoS (which also means we do) use it */
  	if (wme_sta) {
  		fc |= cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
  		hdrlen += 2;
  	}
  
  	/*
  	 * Drop unicast frames to unauthorised stations unless they are
  	 * EAPOL frames from the local station.
  	 */
  	if (unlikely(!ieee80211_vif_is_mesh(&sdata->vif) &&
  		     (sdata->vif.type != NL80211_IFTYPE_OCB) &&
  		     !multicast && !authorized &&
  		     (cpu_to_be16(ethertype) != sdata->control_port_protocol ||
  		      !ether_addr_equal(sdata->vif.addr, skb->data + ETH_ALEN)))) {
  #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
  		net_info_ratelimited("%s: dropped frame to %pM (unauthorized port)\n",
  				    sdata->name, hdr.addr1);
  #endif
  
  		I802_DEBUG_INC(local->tx_handlers_drop_unauth_port);
  
  		ret = -EPERM;
  		goto free;
  	}
  
  	if (unlikely(!multicast && skb->sk &&
  		     skb_shinfo(skb)->tx_flags & SKBTX_WIFI_STATUS)) {
  		struct sk_buff *ack_skb = skb_clone_sk(skb);
  
  		if (ack_skb) {
  			unsigned long flags;
  			int id;
  
  			spin_lock_irqsave(&local->ack_status_lock, flags);
  			id = idr_alloc(&local->ack_status_frames, ack_skb,
  				       1, 0x10000, GFP_ATOMIC);
  			spin_unlock_irqrestore(&local->ack_status_lock, flags);
  
  			if (id >= 0) {
  				info_id = id;
  				info_flags |= IEEE80211_TX_CTL_REQ_TX_STATUS;
  			} else {
  				kfree_skb(ack_skb);
  			}
  		}
  	}
  
  	/*
  	 * If the skb is shared we need to obtain our own copy.
  	 */
  	if (skb_shared(skb)) {
  		struct sk_buff *tmp_skb = skb;
  
  		/* can't happen -- skb is a clone if info_id != 0 */
  		WARN_ON(info_id);
  
  		skb = skb_clone(skb, GFP_ATOMIC);
  		kfree_skb(tmp_skb);
  
  		if (!skb) {
  			ret = -ENOMEM;
  			goto free;
  		}
  	}
  
  	hdr.frame_control = fc;
  	hdr.duration_id = 0;
  	hdr.seq_ctrl = 0;
  
  	skip_header_bytes = ETH_HLEN;
  	if (ethertype == ETH_P_AARP || ethertype == ETH_P_IPX) {
  		encaps_data = bridge_tunnel_header;
  		encaps_len = sizeof(bridge_tunnel_header);
  		skip_header_bytes -= 2;
  	} else if (ethertype >= ETH_P_802_3_MIN) {
  		encaps_data = rfc1042_header;
  		encaps_len = sizeof(rfc1042_header);
  		skip_header_bytes -= 2;
  	} else {
  		encaps_data = NULL;
  		encaps_len = 0;
  	}
  
  	skb_pull(skb, skip_header_bytes);
  	head_need = hdrlen + encaps_len + meshhdrlen - skb_headroom(skb);
  
  	/*
  	 * So we need to modify the skb header and hence need a copy of
  	 * that. The head_need variable above doesn't, so far, include
  	 * the needed header space that we don't need right away. If we
  	 * can, then we don't reallocate right now but only after the
  	 * frame arrives at the master device (if it does...)
  	 *
  	 * If we cannot, however, then we will reallocate to include all
  	 * the ever needed space. Also, if we need to reallocate it anyway,
  	 * make it big enough for everything we may ever need.
  	 */
  
  	if (head_need > 0 || skb_cloned(skb)) {
  		head_need += sdata->encrypt_headroom;
  		head_need += local->tx_headroom;
  		head_need = max_t(int, 0, head_need);
  		if (ieee80211_skb_resize(sdata, skb, head_need, true)) {
  			ieee80211_free_txskb(&local->hw, skb);
  			skb = NULL;
  			return ERR_PTR(-ENOMEM);
  		}
  	}
  
  	if (encaps_data)
  		memcpy(skb_push(skb, encaps_len), encaps_data, encaps_len);
  
  #ifdef CONFIG_MAC80211_MESH
  	if (meshhdrlen > 0)
  		memcpy(skb_push(skb, meshhdrlen), &mesh_hdr, meshhdrlen);
  #endif
  
  	if (ieee80211_is_data_qos(fc)) {
  		__le16 *qos_control;
  
  		qos_control = skb_push(skb, 2);
  		memcpy(skb_push(skb, hdrlen - 2), &hdr, hdrlen - 2);
  		/*
  		 * Maybe we could actually set some fields here, for now just
  		 * initialise to zero to indicate no special operation.
  		 */
  		*qos_control = 0;
  	} else
  		memcpy(skb_push(skb, hdrlen), &hdr, hdrlen);
  
  	skb_reset_mac_header(skb);
  
  	info = IEEE80211_SKB_CB(skb);
  	memset(info, 0, sizeof(*info));
  
  	info->flags = info_flags;
  	info->ack_frame_id = info_id;
  	info->band = band;
  
  	return skb;
   free:
  	kfree_skb(skb);
  	return ERR_PTR(ret);
  }
  
  /*
   * fast-xmit overview
   *
   * The core idea of this fast-xmit is to remove per-packet checks by checking
   * them out of band. ieee80211_check_fast_xmit() implements the out-of-band
   * checks that are needed to get the sta->fast_tx pointer assigned, after which
   * much less work can be done per packet. For example, fragmentation must be
   * disabled or the fast_tx pointer will not be set. All the conditions are seen
   * in the code here.
   *
   * Once assigned, the fast_tx data structure also caches the per-packet 802.11
   * header and other data to aid packet processing in ieee80211_xmit_fast().
   *
   * The most difficult part of this is that when any of these assumptions
   * change, an external trigger (i.e. a call to ieee80211_clear_fast_xmit(),
   * ieee80211_check_fast_xmit() or friends) is required to reset the data,
   * since the per-packet code no longer checks the conditions. This is reflected
   * by the calls to these functions throughout the rest of the code, and must be
   * maintained if any of the TX path checks change.
   */
  
  void ieee80211_check_fast_xmit(struct sta_info *sta)
  {
  	struct ieee80211_fast_tx build = {}, *fast_tx = NULL, *old;
  	struct ieee80211_local *local = sta->local;
  	struct ieee80211_sub_if_data *sdata = sta->sdata;
  	struct ieee80211_hdr *hdr = (void *)build.hdr;
  	struct ieee80211_chanctx_conf *chanctx_conf;
  	__le16 fc;
  
  	if (!ieee80211_hw_check(&local->hw, SUPPORT_FAST_XMIT))
  		return;
  
  	/* Locking here protects both the pointer itself, and against concurrent
  	 * invocations winning data access races to, e.g., the key pointer that
  	 * is used.
  	 * Without it, the invocation of this function right after the key
  	 * pointer changes wouldn't be sufficient, as another CPU could access
  	 * the pointer, then stall, and then do the cache update after the CPU
  	 * that invalidated the key.
  	 * With the locking, such scenarios cannot happen as the check for the
  	 * key and the fast-tx assignment are done atomically, so the CPU that
  	 * modifies the key will either wait or other one will see the key
  	 * cleared/changed already.
  	 */
  	spin_lock_bh(&sta->lock);
  	if (ieee80211_hw_check(&local->hw, SUPPORTS_PS) &&
  	    !ieee80211_hw_check(&local->hw, SUPPORTS_DYNAMIC_PS) &&
  	    sdata->vif.type == NL80211_IFTYPE_STATION)
  		goto out;
  
  	if (!test_sta_flag(sta, WLAN_STA_AUTHORIZED))
  		goto out;
  
  	if (test_sta_flag(sta, WLAN_STA_PS_STA) ||
  	    test_sta_flag(sta, WLAN_STA_PS_DRIVER) ||
  	    test_sta_flag(sta, WLAN_STA_PS_DELIVER) ||
  	    test_sta_flag(sta, WLAN_STA_CLEAR_PS_FILT))
  		goto out;
  
  	if (sdata->noack_map)
  		goto out;
  
  	/* fast-xmit doesn't handle fragmentation at all */
  	if (local->hw.wiphy->frag_threshold != (u32)-1 &&
  	    !ieee80211_hw_check(&local->hw, SUPPORTS_TX_FRAG))
  		goto out;
  
  	rcu_read_lock();
  	chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  	if (!chanctx_conf) {
  		rcu_read_unlock();
  		goto out;
  	}
  	build.band = chanctx_conf->def.chan->band;
  	rcu_read_unlock();
  
  	fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA);
  
  	switch (sdata->vif.type) {
  	case NL80211_IFTYPE_ADHOC:
  		/* DA SA BSSID */
  		build.da_offs = offsetof(struct ieee80211_hdr, addr1);
  		build.sa_offs = offsetof(struct ieee80211_hdr, addr2);
  		memcpy(hdr->addr3, sdata->u.ibss.bssid, ETH_ALEN);
  		build.hdr_len = 24;
  		break;
  	case NL80211_IFTYPE_STATION:
  		if (test_sta_flag(sta, WLAN_STA_TDLS_PEER)) {
  			/* DA SA BSSID */
  			build.da_offs = offsetof(struct ieee80211_hdr, addr1);
  			build.sa_offs = offsetof(struct ieee80211_hdr, addr2);
  			memcpy(hdr->addr3, sdata->u.mgd.bssid, ETH_ALEN);
  			build.hdr_len = 24;
  			break;
  		}
  
  		if (sdata->u.mgd.use_4addr) {
  			/* non-regular ethertype cannot use the fastpath */
  			fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS |
  					  IEEE80211_FCTL_TODS);
  			/* RA TA DA SA */
  			memcpy(hdr->addr1, sdata->u.mgd.bssid, ETH_ALEN);
  			memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
  			build.da_offs = offsetof(struct ieee80211_hdr, addr3);
  			build.sa_offs = offsetof(struct ieee80211_hdr, addr4);
  			build.hdr_len = 30;
  			break;
  		}
  		fc |= cpu_to_le16(IEEE80211_FCTL_TODS);
  		/* BSSID SA DA */
  		memcpy(hdr->addr1, sdata->u.mgd.bssid, ETH_ALEN);
  		build.da_offs = offsetof(struct ieee80211_hdr, addr3);
  		build.sa_offs = offsetof(struct ieee80211_hdr, addr2);
  		build.hdr_len = 24;
  		break;
  	case NL80211_IFTYPE_AP_VLAN:
  		if (sdata->wdev.use_4addr) {
  			fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS |
  					  IEEE80211_FCTL_TODS);
  			/* RA TA DA SA */
  			memcpy(hdr->addr1, sta->sta.addr, ETH_ALEN);
  			memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
  			build.da_offs = offsetof(struct ieee80211_hdr, addr3);
  			build.sa_offs = offsetof(struct ieee80211_hdr, addr4);
  			build.hdr_len = 30;
  			break;
  		}
  		/* fall through */
  	case NL80211_IFTYPE_AP:
  		fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS);
  		/* DA BSSID SA */
  		build.da_offs = offsetof(struct ieee80211_hdr, addr1);
  		memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
  		build.sa_offs = offsetof(struct ieee80211_hdr, addr3);
  		build.hdr_len = 24;
  		break;
  	default:
  		/* not handled on fast-xmit */
  		goto out;
  	}
  
  	if (sta->sta.wme) {
  		build.hdr_len += 2;
  		fc |= cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
  	}
  
  	/* We store the key here so there's no point in using rcu_dereference()
  	 * but that's fine because the code that changes the pointers will call
  	 * this function after doing so. For a single CPU that would be enough,
  	 * for multiple see the comment above.
  	 */
  	build.key = rcu_access_pointer(sta->ptk[sta->ptk_idx]);
  	if (!build.key)
  		build.key = rcu_access_pointer(sdata->default_unicast_key);
  	if (build.key) {
  		bool gen_iv, iv_spc, mmic;
  
  		gen_iv = build.key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV;
  		iv_spc = build.key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE;
  		mmic = build.key->conf.flags &
  			(IEEE80211_KEY_FLAG_GENERATE_MMIC |
  			 IEEE80211_KEY_FLAG_PUT_MIC_SPACE);
  
  		/* don't handle software crypto */
  		if (!(build.key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
  			goto out;
  
  		switch (build.key->conf.cipher) {
  		case WLAN_CIPHER_SUITE_CCMP:
  		case WLAN_CIPHER_SUITE_CCMP_256:
  			/* add fixed key ID */
  			if (gen_iv) {
  				(build.hdr + build.hdr_len)[3] =
  					0x20 | (build.key->conf.keyidx << 6);
  				build.pn_offs = build.hdr_len;
  			}
  			if (gen_iv || iv_spc)
  				build.hdr_len += IEEE80211_CCMP_HDR_LEN;
  			break;
  		case WLAN_CIPHER_SUITE_GCMP:
  		case WLAN_CIPHER_SUITE_GCMP_256:
  			/* add fixed key ID */
  			if (gen_iv) {
  				(build.hdr + build.hdr_len)[3] =
  					0x20 | (build.key->conf.keyidx << 6);
  				build.pn_offs = build.hdr_len;
  			}
  			if (gen_iv || iv_spc)
  				build.hdr_len += IEEE80211_GCMP_HDR_LEN;
  			break;
  		case WLAN_CIPHER_SUITE_TKIP:
  			/* cannot handle MMIC or IV generation in xmit-fast */
  			if (mmic || gen_iv)
  				goto out;
  			if (iv_spc)
  				build.hdr_len += IEEE80211_TKIP_IV_LEN;
  			break;
  		case WLAN_CIPHER_SUITE_WEP40:
  		case WLAN_CIPHER_SUITE_WEP104:
  			/* cannot handle IV generation in fast-xmit */
  			if (gen_iv)
  				goto out;
  			if (iv_spc)
  				build.hdr_len += IEEE80211_WEP_IV_LEN;
  			break;
  		case WLAN_CIPHER_SUITE_AES_CMAC:
  		case WLAN_CIPHER_SUITE_BIP_CMAC_256:
  		case WLAN_CIPHER_SUITE_BIP_GMAC_128:
  		case WLAN_CIPHER_SUITE_BIP_GMAC_256:
  			WARN(1,
  			     "management cipher suite 0x%x enabled for data\n",
  			     build.key->conf.cipher);
  			goto out;
  		default:
  			/* we don't know how to generate IVs for this at all */
  			if (WARN_ON(gen_iv))
  				goto out;
  			/* pure hardware keys are OK, of course */
  			if (!(build.key->flags & KEY_FLAG_CIPHER_SCHEME))
  				break;
  			/* cipher scheme might require space allocation */
  			if (iv_spc &&
  			    build.key->conf.iv_len > IEEE80211_FAST_XMIT_MAX_IV)
  				goto out;
  			if (iv_spc)
  				build.hdr_len += build.key->conf.iv_len;
  		}
  
  		fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
  	}
  
  	hdr->frame_control = fc;
  
  	memcpy(build.hdr + build.hdr_len,
  	       rfc1042_header,  sizeof(rfc1042_header));
  	build.hdr_len += sizeof(rfc1042_header);
  
  	fast_tx = kmemdup(&build, sizeof(build), GFP_ATOMIC);
  	/* if the kmemdup fails, continue w/o fast_tx */
  	if (!fast_tx)
  		goto out;
  
   out:
  	/* we might have raced against another call to this function */
  	old = rcu_dereference_protected(sta->fast_tx,
  					lockdep_is_held(&sta->lock));
  	rcu_assign_pointer(sta->fast_tx, fast_tx);
  	if (old)
  		kfree_rcu(old, rcu_head);
  	spin_unlock_bh(&sta->lock);
  }
  
  void ieee80211_check_fast_xmit_all(struct ieee80211_local *local)
  {
  	struct sta_info *sta;
  
  	rcu_read_lock();
  	list_for_each_entry_rcu(sta, &local->sta_list, list)
  		ieee80211_check_fast_xmit(sta);
  	rcu_read_unlock();
  }
  
  void ieee80211_check_fast_xmit_iface(struct ieee80211_sub_if_data *sdata)
  {
  	struct ieee80211_local *local = sdata->local;
  	struct sta_info *sta;
  
  	rcu_read_lock();
  
  	list_for_each_entry_rcu(sta, &local->sta_list, list) {
  		if (sdata != sta->sdata &&
  		    (!sta->sdata->bss || sta->sdata->bss != sdata->bss))
  			continue;
  		ieee80211_check_fast_xmit(sta);
  	}
  
  	rcu_read_unlock();
  }
  
  void ieee80211_clear_fast_xmit(struct sta_info *sta)
  {
  	struct ieee80211_fast_tx *fast_tx;
  
  	spin_lock_bh(&sta->lock);
  	fast_tx = rcu_dereference_protected(sta->fast_tx,
  					    lockdep_is_held(&sta->lock));
  	RCU_INIT_POINTER(sta->fast_tx, NULL);
  	spin_unlock_bh(&sta->lock);
  
  	if (fast_tx)
  		kfree_rcu(fast_tx, rcu_head);
  }
  
  static bool ieee80211_amsdu_realloc_pad(struct ieee80211_local *local,
  					struct sk_buff *skb, int headroom,
  					int *subframe_len)
  {
  	int amsdu_len = *subframe_len + sizeof(struct ethhdr);
  	int padding = (4 - amsdu_len) & 3;
  
  	if (skb_headroom(skb) < headroom || skb_tailroom(skb) < padding) {
  		I802_DEBUG_INC(local->tx_expand_skb_head);
  
  		if (pskb_expand_head(skb, headroom, padding, GFP_ATOMIC)) {
  			wiphy_debug(local->hw.wiphy,
  				    "failed to reallocate TX buffer\n");
  			return false;
  		}
  	}
  
  	if (padding) {
  		*subframe_len += padding;
  		skb_put_zero(skb, padding);
  	}
  
  	return true;
  }
  
  static bool ieee80211_amsdu_prepare_head(struct ieee80211_sub_if_data *sdata,
  					 struct ieee80211_fast_tx *fast_tx,
  					 struct sk_buff *skb)
  {
  	struct ieee80211_local *local = sdata->local;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  	struct ieee80211_hdr *hdr;
  	struct ethhdr *amsdu_hdr;
  	int hdr_len = fast_tx->hdr_len - sizeof(rfc1042_header);
  	int subframe_len = skb->len - hdr_len;
  	void *data;
  	u8 *qc, *h_80211_src, *h_80211_dst;
  	const u8 *bssid;
  
  	if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
  		return false;
  
  	if (info->control.flags & IEEE80211_TX_CTRL_AMSDU)
  		return true;
  
  	if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(*amsdu_hdr),
  					 &subframe_len))
  		return false;
  
  	data = skb_push(skb, sizeof(*amsdu_hdr));
  	memmove(data, data + sizeof(*amsdu_hdr), hdr_len);
  	hdr = data;
  	amsdu_hdr = data + hdr_len;
  	/* h_80211_src/dst is addr* field within hdr */
  	h_80211_src = data + fast_tx->sa_offs;
  	h_80211_dst = data + fast_tx->da_offs;
  
  	amsdu_hdr->h_proto = cpu_to_be16(subframe_len);
  	ether_addr_copy(amsdu_hdr->h_source, h_80211_src);
  	ether_addr_copy(amsdu_hdr->h_dest, h_80211_dst);
  
  	/* according to IEEE 802.11-2012 8.3.2 table 8-19, the outer SA/DA
  	 * fields needs to be changed to BSSID for A-MSDU frames depending
  	 * on FromDS/ToDS values.
  	 */
  	switch (sdata->vif.type) {
  	case NL80211_IFTYPE_STATION:
  		bssid = sdata->u.mgd.bssid;
  		break;
  	case NL80211_IFTYPE_AP:
  	case NL80211_IFTYPE_AP_VLAN:
  		bssid = sdata->vif.addr;
  		break;
  	default:
  		bssid = NULL;
  	}
  
  	if (bssid && ieee80211_has_fromds(hdr->frame_control))
  		ether_addr_copy(h_80211_src, bssid);
  
  	if (bssid && ieee80211_has_tods(hdr->frame_control))
  		ether_addr_copy(h_80211_dst, bssid);
  
  	qc = ieee80211_get_qos_ctl(hdr);
  	*qc |= IEEE80211_QOS_CTL_A_MSDU_PRESENT;
  
  	info->control.flags |= IEEE80211_TX_CTRL_AMSDU;
  
  	return true;
  }
  
  static bool ieee80211_amsdu_aggregate(struct ieee80211_sub_if_data *sdata,
  				      struct sta_info *sta,
  				      struct ieee80211_fast_tx *fast_tx,
  				      struct sk_buff *skb)
  {
  	struct ieee80211_local *local = sdata->local;
  	struct fq *fq = &local->fq;
  	struct fq_tin *tin;
  	struct fq_flow *flow;
  	u8 tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
  	struct ieee80211_txq *txq = sta->sta.txq[tid];
  	struct txq_info *txqi;
  	struct sk_buff **frag_tail, *head;
  	int subframe_len = skb->len - ETH_ALEN;
  	u8 max_subframes = sta->sta.max_amsdu_subframes;
  	int max_frags = local->hw.max_tx_fragments;
  	int max_amsdu_len = sta->sta.max_amsdu_len;
  	__be16 len;
  	void *data;
  	bool ret = false;
  	unsigned int orig_len;
  	int n = 1, nfrags;
  
  	if (!ieee80211_hw_check(&local->hw, TX_AMSDU))
  		return false;
  
  	if (!txq)
  		return false;
  
  	txqi = to_txq_info(txq);
  	if (test_bit(IEEE80211_TXQ_NO_AMSDU, &txqi->flags))
  		return false;
  
  	if (sta->sta.max_rc_amsdu_len)
  		max_amsdu_len = min_t(int, max_amsdu_len,
  				      sta->sta.max_rc_amsdu_len);
  
  	spin_lock_bh(&fq->lock);
  
  	/* TODO: Ideally aggregation should be done on dequeue to remain
  	 * responsive to environment changes.
  	 */
  
  	tin = &txqi->tin;
  	flow = fq_flow_classify(fq, tin, skb, fq_flow_get_default_func);
  	head = skb_peek_tail(&flow->queue);
  	if (!head)
  		goto out;
  
  	orig_len = head->len;
  
  	if (skb->len + head->len > max_amsdu_len)
  		goto out;
  
  	if (!ieee80211_amsdu_prepare_head(sdata, fast_tx, head))
  		goto out;
  
  	nfrags = 1 + skb_shinfo(skb)->nr_frags;
  	nfrags += 1 + skb_shinfo(head)->nr_frags;
  	frag_tail = &skb_shinfo(head)->frag_list;
  	while (*frag_tail) {
  		nfrags += 1 + skb_shinfo(*frag_tail)->nr_frags;
  		frag_tail = &(*frag_tail)->next;
  		n++;
  	}
  
  	if (max_subframes && n > max_subframes)
  		goto out;
  
  	if (max_frags && nfrags > max_frags)
  		goto out;
  
  	if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(rfc1042_header) + 2,
  					 &subframe_len))
  		goto out;
  
  	ret = true;
  	data = skb_push(skb, ETH_ALEN + 2);
  	memmove(data, data + ETH_ALEN + 2, 2 * ETH_ALEN);
  
  	data += 2 * ETH_ALEN;
  	len = cpu_to_be16(subframe_len);
  	memcpy(data, &len, 2);
  	memcpy(data + 2, rfc1042_header, sizeof(rfc1042_header));
  
  	head->len += skb->len;
  	head->data_len += skb->len;
  	*frag_tail = skb;
  
  	flow->backlog += head->len - orig_len;
  	tin->backlog_bytes += head->len - orig_len;
  
  	fq_recalc_backlog(fq, tin, flow);
  
  out:
  	spin_unlock_bh(&fq->lock);
  
  	return ret;
  }
  
  /*
   * Can be called while the sta lock is held. Anything that can cause packets to
   * be generated will cause deadlock!
   */
  static void ieee80211_xmit_fast_finish(struct ieee80211_sub_if_data *sdata,
  				       struct sta_info *sta, u8 pn_offs,
  				       struct ieee80211_key *key,
  				       struct sk_buff *skb)
  {
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  	struct ieee80211_hdr *hdr = (void *)skb->data;
  	u8 tid = IEEE80211_NUM_TIDS;
  
  	if (key)
  		info->control.hw_key = &key->conf;
  
  	ieee80211_tx_stats(skb->dev, skb->len);
  
  	if (hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_QOS_DATA)) {
  		tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
  		hdr->seq_ctrl = ieee80211_tx_next_seq(sta, tid);
  	} else {
  		info->flags |= IEEE80211_TX_CTL_ASSIGN_SEQ;
  		hdr->seq_ctrl = cpu_to_le16(sdata->sequence_number);
  		sdata->sequence_number += 0x10;
  	}
  
  	if (skb_shinfo(skb)->gso_size)
  		sta->tx_stats.msdu[tid] +=
  			DIV_ROUND_UP(skb->len, skb_shinfo(skb)->gso_size);
  	else
  		sta->tx_stats.msdu[tid]++;
  
  	info->hw_queue = sdata->vif.hw_queue[skb_get_queue_mapping(skb)];
  
  	/* statistics normally done by ieee80211_tx_h_stats (but that
  	 * has to consider fragmentation, so is more complex)
  	 */
  	sta->tx_stats.bytes[skb_get_queue_mapping(skb)] += skb->len;
  	sta->tx_stats.packets[skb_get_queue_mapping(skb)]++;
  
  	if (pn_offs) {
  		u64 pn;
  		u8 *crypto_hdr = skb->data + pn_offs;
  
  		switch (key->conf.cipher) {
  		case WLAN_CIPHER_SUITE_CCMP:
  		case WLAN_CIPHER_SUITE_CCMP_256:
  		case WLAN_CIPHER_SUITE_GCMP:
  		case WLAN_CIPHER_SUITE_GCMP_256:
  			pn = atomic64_inc_return(&key->conf.tx_pn);
  			crypto_hdr[0] = pn;
  			crypto_hdr[1] = pn >> 8;
  			crypto_hdr[4] = pn >> 16;
  			crypto_hdr[5] = pn >> 24;
  			crypto_hdr[6] = pn >> 32;
  			crypto_hdr[7] = pn >> 40;
  			break;
  		}
  	}
  }
  
  static bool ieee80211_xmit_fast(struct ieee80211_sub_if_data *sdata,
  				struct sta_info *sta,
  				struct ieee80211_fast_tx *fast_tx,
  				struct sk_buff *skb)
  {
  	struct ieee80211_local *local = sdata->local;
  	u16 ethertype = (skb->data[12] << 8) | skb->data[13];
  	int extra_head = fast_tx->hdr_len - (ETH_HLEN - 2);
  	int hw_headroom = sdata->local->hw.extra_tx_headroom;
  	struct ethhdr eth;
  	struct ieee80211_tx_info *info;
  	struct ieee80211_hdr *hdr = (void *)fast_tx->hdr;
  	struct ieee80211_tx_data tx;
  	ieee80211_tx_result r;
  	struct tid_ampdu_tx *tid_tx = NULL;
  	u8 tid = IEEE80211_NUM_TIDS;
  
  	/* control port protocol needs a lot of special handling */
  	if (cpu_to_be16(ethertype) == sdata->control_port_protocol)
  		return false;
  
  	/* only RFC 1042 SNAP */
  	if (ethertype < ETH_P_802_3_MIN)
  		return false;
  
  	/* don't handle TX status request here either */
  	if (skb->sk && skb_shinfo(skb)->tx_flags & SKBTX_WIFI_STATUS)
  		return false;
  
  	if (hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_QOS_DATA)) {
  		tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
  		tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
  		if (tid_tx) {
  			if (!test_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state))
  				return false;
  			if (tid_tx->timeout)
  				tid_tx->last_tx = jiffies;
  		}
  	}
  
  	/* after this point (skb is modified) we cannot return false */
  
  	if (skb_shared(skb)) {
  		struct sk_buff *tmp_skb = skb;
  
  		skb = skb_clone(skb, GFP_ATOMIC);
  		kfree_skb(tmp_skb);
  
  		if (!skb)
  			return true;
  	}
  
  	if ((hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_QOS_DATA)) &&
  	    ieee80211_amsdu_aggregate(sdata, sta, fast_tx, skb))
  		return true;
  
  	/* will not be crypto-handled beyond what we do here, so use false
  	 * as the may-encrypt argument for the resize to not account for
  	 * more room than we already have in 'extra_head'
  	 */
  	if (unlikely(ieee80211_skb_resize(sdata, skb,
  					  max_t(int, extra_head + hw_headroom -
  						     skb_headroom(skb), 0),
  					  false))) {
  		kfree_skb(skb);
  		return true;
  	}
  
  	memcpy(&eth, skb->data, ETH_HLEN - 2);
  	hdr = skb_push(skb, extra_head);
  	memcpy(skb->data, fast_tx->hdr, fast_tx->hdr_len);
  	memcpy(skb->data + fast_tx->da_offs, eth.h_dest, ETH_ALEN);
  	memcpy(skb->data + fast_tx->sa_offs, eth.h_source, ETH_ALEN);
  
  	info = IEEE80211_SKB_CB(skb);
  	memset(info, 0, sizeof(*info));
  	info->band = fast_tx->band;
  	info->control.vif = &sdata->vif;
  	info->flags = IEEE80211_TX_CTL_FIRST_FRAGMENT |
  		      IEEE80211_TX_CTL_DONTFRAG |
  		      (tid_tx ? IEEE80211_TX_CTL_AMPDU : 0);
  	info->control.flags = IEEE80211_TX_CTRL_FAST_XMIT;
  
  	if (hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_QOS_DATA)) {
  		tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
  		*ieee80211_get_qos_ctl(hdr) = tid;
  	}
  
  	__skb_queue_head_init(&tx.skbs);
  
  	tx.flags = IEEE80211_TX_UNICAST;
  	tx.local = local;
  	tx.sdata = sdata;
  	tx.sta = sta;
  	tx.key = fast_tx->key;
  
  	if (!ieee80211_hw_check(&local->hw, HAS_RATE_CONTROL)) {
  		tx.skb = skb;
  		r = ieee80211_tx_h_rate_ctrl(&tx);
  		skb = tx.skb;
  		tx.skb = NULL;
  
  		if (r != TX_CONTINUE) {
  			if (r != TX_QUEUED)
  				kfree_skb(skb);
  			return true;
  		}
  	}
  
  	if (ieee80211_queue_skb(local, sdata, sta, skb))
  		return true;
  
  	ieee80211_xmit_fast_finish(sdata, sta, fast_tx->pn_offs,
  				   fast_tx->key, skb);
  
  	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
  		sdata = container_of(sdata->bss,
  				     struct ieee80211_sub_if_data, u.ap);
  
  	__skb_queue_tail(&tx.skbs, skb);
  	ieee80211_tx_frags(local, &sdata->vif, &sta->sta, &tx.skbs, false);
  	return true;
  }
  
  struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
  				     struct ieee80211_txq *txq)
  {
  	struct ieee80211_local *local = hw_to_local(hw);
  	struct txq_info *txqi = container_of(txq, struct txq_info, txq);
  	struct ieee80211_hdr *hdr;
  	struct sk_buff *skb = NULL;
  	struct fq *fq = &local->fq;
  	struct fq_tin *tin = &txqi->tin;
  	struct ieee80211_tx_info *info;
  	struct ieee80211_tx_data tx;
  	ieee80211_tx_result r;
  	struct ieee80211_vif *vif;
  
  	spin_lock_bh(&fq->lock);
  
  	if (test_bit(IEEE80211_TXQ_STOP, &txqi->flags))
  		goto out;
  
  	/* Make sure fragments stay together. */
  	skb = __skb_dequeue(&txqi->frags);
  	if (skb)
  		goto out;
  
  begin:
  	skb = fq_tin_dequeue(fq, tin, fq_tin_dequeue_func);
  	if (!skb)
  		goto out;
  
  	hdr = (struct ieee80211_hdr *)skb->data;
  	info = IEEE80211_SKB_CB(skb);
  
  	memset(&tx, 0, sizeof(tx));
  	__skb_queue_head_init(&tx.skbs);
  	tx.local = local;
  	tx.skb = skb;
  	tx.sdata = vif_to_sdata(info->control.vif);
  
  	if (txq->sta)
  		tx.sta = container_of(txq->sta, struct sta_info, sta);
  
  	/*
  	 * The key can be removed while the packet was queued, so need to call
  	 * this here to get the current key.
  	 */
  	r = ieee80211_tx_h_select_key(&tx);
  	if (r != TX_CONTINUE) {
  		ieee80211_free_txskb(&local->hw, skb);
  		goto begin;
  	}
  
  	if (test_bit(IEEE80211_TXQ_AMPDU, &txqi->flags))
  		info->flags |= IEEE80211_TX_CTL_AMPDU;
  	else
  		info->flags &= ~IEEE80211_TX_CTL_AMPDU;
  
  	if (info->control.flags & IEEE80211_TX_CTRL_FAST_XMIT) {
  		struct sta_info *sta = container_of(txq->sta, struct sta_info,
  						    sta);
  		u8 pn_offs = 0;
  
  		if (tx.key &&
  		    (tx.key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV))
  			pn_offs = ieee80211_hdrlen(hdr->frame_control);
  
  		ieee80211_xmit_fast_finish(sta->sdata, sta, pn_offs,
  					   tx.key, skb);
  	} else {
  		if (invoke_tx_handlers_late(&tx))
  			goto begin;
  
  		skb = __skb_dequeue(&tx.skbs);
  
  		if (!skb_queue_empty(&tx.skbs))
  			skb_queue_splice_tail(&tx.skbs, &txqi->frags);
  	}
  
  	if (skb && skb_has_frag_list(skb) &&
  	    !ieee80211_hw_check(&local->hw, TX_FRAG_LIST)) {
  		if (skb_linearize(skb)) {
  			ieee80211_free_txskb(&local->hw, skb);
  			goto begin;
  		}
  	}
  
  	switch (tx.sdata->vif.type) {
  	case NL80211_IFTYPE_MONITOR:
  		if (tx.sdata->u.mntr.flags & MONITOR_FLAG_ACTIVE) {
  			vif = &tx.sdata->vif;
  			break;
  		}
  		tx.sdata = rcu_dereference(local->monitor_sdata);
  		if (tx.sdata) {
  			vif = &tx.sdata->vif;
  			info->hw_queue =
  				vif->hw_queue[skb_get_queue_mapping(skb)];
  		} else if (ieee80211_hw_check(&local->hw, QUEUE_CONTROL)) {
  			ieee80211_free_txskb(&local->hw, skb);
  			goto begin;
  		} else {
  			vif = NULL;
  		}
  		break;
  	case NL80211_IFTYPE_AP_VLAN:
  		tx.sdata = container_of(tx.sdata->bss,
  					struct ieee80211_sub_if_data, u.ap);
  		/* fall through */
  	default:
  		vif = &tx.sdata->vif;
  		break;
  	}
  
  	IEEE80211_SKB_CB(skb)->control.vif = vif;
  out:
  	spin_unlock_bh(&fq->lock);
  
  	return skb;
  }
  EXPORT_SYMBOL(ieee80211_tx_dequeue);
  
  void __ieee80211_subif_start_xmit(struct sk_buff *skb,
  				  struct net_device *dev,
  				  u32 info_flags)
  {
  	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
  	struct sta_info *sta;
  	struct sk_buff *next;
  
  	if (unlikely(skb->len < ETH_HLEN)) {
  		kfree_skb(skb);
  		return;
  	}
  
  	rcu_read_lock();
  
  	if (ieee80211_lookup_ra_sta(sdata, skb, &sta))
  		goto out_free;
  
  	if (!IS_ERR_OR_NULL(sta)) {
  		struct ieee80211_fast_tx *fast_tx;
  
  		/* We need a bit of data queued to build aggregates properly, so
  		 * instruct the TCP stack to allow more than a single ms of data
  		 * to be queued in the stack. The value is a bit-shift of 1
  		 * second, so 8 is ~4ms of queued data. Only affects local TCP
  		 * sockets.
  		 */
  		sk_pacing_shift_update(skb->sk, 8);
  
  		fast_tx = rcu_dereference(sta->fast_tx);
  
  		if (fast_tx &&
  		    ieee80211_xmit_fast(sdata, sta, fast_tx, skb))
  			goto out;
  	}
  
  	if (skb_is_gso(skb)) {
  		struct sk_buff *segs;
  
  		segs = skb_gso_segment(skb, 0);
  		if (IS_ERR(segs)) {
  			goto out_free;
  		} else if (segs) {
  			consume_skb(skb);
  			skb = segs;
  		}
  	} else {
  		/* we cannot process non-linear frames on this path */
  		if (skb_linearize(skb)) {
  			kfree_skb(skb);
  			goto out;
  		}
  
  		/* the frame could be fragmented, software-encrypted, and other
  		 * things so we cannot really handle checksum offload with it -
  		 * fix it up in software before we handle anything else.
  		 */
  		if (skb->ip_summed == CHECKSUM_PARTIAL) {
  			skb_set_transport_header(skb,
  						 skb_checksum_start_offset(skb));
  			if (skb_checksum_help(skb))
  				goto out_free;
  		}
  	}
  
  	next = skb;
  	while (next) {
  		skb = next;
  		next = skb->next;
  
  		skb->prev = NULL;
  		skb->next = NULL;
  
  		skb = ieee80211_build_hdr(sdata, skb, info_flags, sta);
  		if (IS_ERR(skb))
  			goto out;
  
  		ieee80211_tx_stats(dev, skb->len);
  
  		ieee80211_xmit(sdata, sta, skb);
  	}
  	goto out;
   out_free:
  	kfree_skb(skb);
   out:
  	rcu_read_unlock();
  }
  
  static int ieee80211_change_da(struct sk_buff *skb, struct sta_info *sta)
  {
  	struct ethhdr *eth;
  	int err;
  
  	err = skb_ensure_writable(skb, ETH_HLEN);
  	if (unlikely(err))
  		return err;
  
  	eth = (void *)skb->data;
  	ether_addr_copy(eth->h_dest, sta->sta.addr);
  
  	return 0;
  }
  
  static bool ieee80211_multicast_to_unicast(struct sk_buff *skb,
  					   struct net_device *dev)
  {
  	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
  	const struct ethhdr *eth = (void *)skb->data;
  	const struct vlan_ethhdr *ethvlan = (void *)skb->data;
  	__be16 ethertype;
  
  	if (likely(!is_multicast_ether_addr(eth->h_dest)))
  		return false;
  
  	switch (sdata->vif.type) {
  	case NL80211_IFTYPE_AP_VLAN:
  		if (sdata->u.vlan.sta)
  			return false;
  		if (sdata->wdev.use_4addr)
  			return false;
  		/* fall through */
  	case NL80211_IFTYPE_AP:
  		/* check runtime toggle for this bss */
  		if (!sdata->bss->multicast_to_unicast)
  			return false;
  		break;
  	default:
  		return false;
  	}
  
  	/* multicast to unicast conversion only for some payload */
  	ethertype = eth->h_proto;
  	if (ethertype == htons(ETH_P_8021Q) && skb->len >= VLAN_ETH_HLEN)
  		ethertype = ethvlan->h_vlan_encapsulated_proto;
  	switch (ethertype) {
  	case htons(ETH_P_ARP):
  	case htons(ETH_P_IP):
  	case htons(ETH_P_IPV6):
  		break;
  	default:
  		return false;
  	}
  
  	return true;
  }
  
  static void
  ieee80211_convert_to_unicast(struct sk_buff *skb, struct net_device *dev,
  			     struct sk_buff_head *queue)
  {
  	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
  	struct ieee80211_local *local = sdata->local;
  	const struct ethhdr *eth = (struct ethhdr *)skb->data;
  	struct sta_info *sta, *first = NULL;
  	struct sk_buff *cloned_skb;
  
  	rcu_read_lock();
  
  	list_for_each_entry_rcu(sta, &local->sta_list, list) {
  		if (sdata != sta->sdata)
  			/* AP-VLAN mismatch */
  			continue;
  		if (unlikely(ether_addr_equal(eth->h_source, sta->sta.addr)))
  			/* do not send back to source */
  			continue;
  		if (!first) {
  			first = sta;
  			continue;
  		}
  		cloned_skb = skb_clone(skb, GFP_ATOMIC);
  		if (!cloned_skb)
  			goto multicast;
  		if (unlikely(ieee80211_change_da(cloned_skb, sta))) {
  			dev_kfree_skb(cloned_skb);
  			goto multicast;
  		}
  		__skb_queue_tail(queue, cloned_skb);
  	}
  
  	if (likely(first)) {
  		if (unlikely(ieee80211_change_da(skb, first)))
  			goto multicast;
  		__skb_queue_tail(queue, skb);
  	} else {
  		/* no STA connected, drop */
  		kfree_skb(skb);
  		skb = NULL;
  	}
  
  	goto out;
  multicast:
  	__skb_queue_purge(queue);
  	__skb_queue_tail(queue, skb);
  out:
  	rcu_read_unlock();
  }
  
  /**
   * ieee80211_subif_start_xmit - netif start_xmit function for 802.3 vifs
   * @skb: packet to be sent
   * @dev: incoming interface
   *
   * On failure skb will be freed.
   */
  netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
  				       struct net_device *dev)
  {
  	if (unlikely(ieee80211_multicast_to_unicast(skb, dev))) {
  		struct sk_buff_head queue;
  
  		__skb_queue_head_init(&queue);
  		ieee80211_convert_to_unicast(skb, dev, &queue);
  		while ((skb = __skb_dequeue(&queue)))
  			__ieee80211_subif_start_xmit(skb, dev, 0);
  	} else {
  		__ieee80211_subif_start_xmit(skb, dev, 0);
  	}
  
  	return NETDEV_TX_OK;
  }
  
  struct sk_buff *
  ieee80211_build_data_template(struct ieee80211_sub_if_data *sdata,
  			      struct sk_buff *skb, u32 info_flags)
  {
  	struct ieee80211_hdr *hdr;
  	struct ieee80211_tx_data tx = {
  		.local = sdata->local,
  		.sdata = sdata,
  	};
  	struct sta_info *sta;
  
  	rcu_read_lock();
  
  	if (ieee80211_lookup_ra_sta(sdata, skb, &sta)) {
  		kfree_skb(skb);
  		skb = ERR_PTR(-EINVAL);
  		goto out;
  	}
  
  	skb = ieee80211_build_hdr(sdata, skb, info_flags, sta);
  	if (IS_ERR(skb))
  		goto out;
  
  	hdr = (void *)skb->data;
  	tx.sta = sta_info_get(sdata, hdr->addr1);
  	tx.skb = skb;
  
  	if (ieee80211_tx_h_select_key(&tx) != TX_CONTINUE) {
  		rcu_read_unlock();
  		kfree_skb(skb);
  		return ERR_PTR(-EINVAL);
  	}
  
  out:
  	rcu_read_unlock();
  	return skb;
  }
  
  /*
   * ieee80211_clear_tx_pending may not be called in a context where
   * it is possible that it packets could come in again.
   */
  void ieee80211_clear_tx_pending(struct ieee80211_local *local)
  {
  	struct sk_buff *skb;
  	int i;
  
  	for (i = 0; i < local->hw.queues; i++) {
  		while ((skb = skb_dequeue(&local->pending[i])) != NULL)
  			ieee80211_free_txskb(&local->hw, skb);
  	}
  }
  
  /*
   * Returns false if the frame couldn't be transmitted but was queued instead,
   * which in this case means re-queued -- take as an indication to stop sending
   * more pending frames.
   */
  static bool ieee80211_tx_pending_skb(struct ieee80211_local *local,
  				     struct sk_buff *skb)
  {
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  	struct ieee80211_sub_if_data *sdata;
  	struct sta_info *sta;
  	struct ieee80211_hdr *hdr;
  	bool result;
  	struct ieee80211_chanctx_conf *chanctx_conf;
  
  	sdata = vif_to_sdata(info->control.vif);
  
  	if (info->flags & IEEE80211_TX_INTFL_NEED_TXPROCESSING) {
  		chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  		if (unlikely(!chanctx_conf)) {
  			dev_kfree_skb(skb);
  			return true;
  		}
  		info->band = chanctx_conf->def.chan->band;
  		result = ieee80211_tx(sdata, NULL, skb, true);
  	} else {
  		struct sk_buff_head skbs;
  
  		__skb_queue_head_init(&skbs);
  		__skb_queue_tail(&skbs, skb);
  
  		hdr = (struct ieee80211_hdr *)skb->data;
  		sta = sta_info_get(sdata, hdr->addr1);
  
  		result = __ieee80211_tx(local, &skbs, skb->len, sta, true);
  	}
  
  	return result;
  }
  
  /*
   * Transmit all pending packets. Called from tasklet.
   */
  void ieee80211_tx_pending(unsigned long data)
  {
  	struct ieee80211_local *local = (struct ieee80211_local *)data;
  	unsigned long flags;
  	int i;
  	bool txok;
  
  	rcu_read_lock();
  
  	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
  	for (i = 0; i < local->hw.queues; i++) {
  		/*
  		 * If queue is stopped by something other than due to pending
  		 * frames, or we have no pending frames, proceed to next queue.
  		 */
  		if (local->queue_stop_reasons[i] ||
  		    skb_queue_empty(&local->pending[i]))
  			continue;
  
  		while (!skb_queue_empty(&local->pending[i])) {
  			struct sk_buff *skb = __skb_dequeue(&local->pending[i]);
  			struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  
  			if (WARN_ON(!info->control.vif)) {
  				ieee80211_free_txskb(&local->hw, skb);
  				continue;
  			}
  
  			spin_unlock_irqrestore(&local->queue_stop_reason_lock,
  						flags);
  
  			txok = ieee80211_tx_pending_skb(local, skb);
  			spin_lock_irqsave(&local->queue_stop_reason_lock,
  					  flags);
  			if (!txok)
  				break;
  		}
  
  		if (skb_queue_empty(&local->pending[i]))
  			ieee80211_propagate_queue_wake(local, i);
  	}
  	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
  
  	rcu_read_unlock();
  }
  
  /* functions for drivers to get certain frames */
  
  static void __ieee80211_beacon_add_tim(struct ieee80211_sub_if_data *sdata,
  				       struct ps_data *ps, struct sk_buff *skb,
  				       bool is_template)
  {
  	u8 *pos, *tim;
  	int aid0 = 0;
  	int i, have_bits = 0, n1, n2;
  
  	/* Generate bitmap for TIM only if there are any STAs in power save
  	 * mode. */
  	if (atomic_read(&ps->num_sta_ps) > 0)
  		/* in the hope that this is faster than
  		 * checking byte-for-byte */
  		have_bits = !bitmap_empty((unsigned long *)ps->tim,
  					  IEEE80211_MAX_AID+1);
  	if (!is_template) {
  		if (ps->dtim_count == 0)
  			ps->dtim_count = sdata->vif.bss_conf.dtim_period - 1;
  		else
  			ps->dtim_count--;
  	}
  
  	tim = pos = skb_put(skb, 6);
  	*pos++ = WLAN_EID_TIM;
  	*pos++ = 4;
  	*pos++ = ps->dtim_count;
  	*pos++ = sdata->vif.bss_conf.dtim_period;
  
  	if (ps->dtim_count == 0 && !skb_queue_empty(&ps->bc_buf))
  		aid0 = 1;
  
  	ps->dtim_bc_mc = aid0 == 1;
  
  	if (have_bits) {
  		/* Find largest even number N1 so that bits numbered 1 through
  		 * (N1 x 8) - 1 in the bitmap are 0 and number N2 so that bits
  		 * (N2 + 1) x 8 through 2007 are 0. */
  		n1 = 0;
  		for (i = 0; i < IEEE80211_MAX_TIM_LEN; i++) {
  			if (ps->tim[i]) {
  				n1 = i & 0xfe;
  				break;
  			}
  		}
  		n2 = n1;
  		for (i = IEEE80211_MAX_TIM_LEN - 1; i >= n1; i--) {
  			if (ps->tim[i]) {
  				n2 = i;
  				break;
  			}
  		}
  
  		/* Bitmap control */
  		*pos++ = n1 | aid0;
  		/* Part Virt Bitmap */
  		skb_put(skb, n2 - n1);
  		memcpy(pos, ps->tim + n1, n2 - n1 + 1);
  
  		tim[1] = n2 - n1 + 4;
  	} else {
  		*pos++ = aid0; /* Bitmap control */
  		*pos++ = 0; /* Part Virt Bitmap */
  	}
  }
  
  static int ieee80211_beacon_add_tim(struct ieee80211_sub_if_data *sdata,
  				    struct ps_data *ps, struct sk_buff *skb,
  				    bool is_template)
  {
  	struct ieee80211_local *local = sdata->local;
  
  	/*
  	 * Not very nice, but we want to allow the driver to call
  	 * ieee80211_beacon_get() as a response to the set_tim()
  	 * callback. That, however, is already invoked under the
  	 * sta_lock to guarantee consistent and race-free update
  	 * of the tim bitmap in mac80211 and the driver.
  	 */
  	if (local->tim_in_locked_section) {
  		__ieee80211_beacon_add_tim(sdata, ps, skb, is_template);
  	} else {
  		spin_lock_bh(&local->tim_lock);
  		__ieee80211_beacon_add_tim(sdata, ps, skb, is_template);
  		spin_unlock_bh(&local->tim_lock);
  	}
  
  	return 0;
  }
  
  static void ieee80211_set_csa(struct ieee80211_sub_if_data *sdata,
  			      struct beacon_data *beacon)
  {
  	struct probe_resp *resp;
  	u8 *beacon_data;
  	size_t beacon_data_len;
  	int i;
  	u8 count = beacon->csa_current_counter;
  
  	switch (sdata->vif.type) {
  	case NL80211_IFTYPE_AP:
  		beacon_data = beacon->tail;
  		beacon_data_len = beacon->tail_len;
  		break;
  	case NL80211_IFTYPE_ADHOC:
  		beacon_data = beacon->head;
  		beacon_data_len = beacon->head_len;
  		break;
  	case NL80211_IFTYPE_MESH_POINT:
  		beacon_data = beacon->head;
  		beacon_data_len = beacon->head_len;
  		break;
  	default:
  		return;
  	}
  
  	rcu_read_lock();
  	for (i = 0; i < IEEE80211_MAX_CSA_COUNTERS_NUM; ++i) {
  		resp = rcu_dereference(sdata->u.ap.probe_resp);
  
  		if (beacon->csa_counter_offsets[i]) {
  			if (WARN_ON_ONCE(beacon->csa_counter_offsets[i] >=
  					 beacon_data_len)) {
  				rcu_read_unlock();
  				return;
  			}
  
  			beacon_data[beacon->csa_counter_offsets[i]] = count;
  		}
  
  		if (sdata->vif.type == NL80211_IFTYPE_AP && resp)
  			resp->data[resp->csa_counter_offsets[i]] = count;
  	}
  	rcu_read_unlock();
  }
  
  static u8 __ieee80211_csa_update_counter(struct beacon_data *beacon)
  {
  	beacon->csa_current_counter--;
  
  	/* the counter should never reach 0 */
  	WARN_ON_ONCE(!beacon->csa_current_counter);
  
  	return beacon->csa_current_counter;
  }
  
  u8 ieee80211_csa_update_counter(struct ieee80211_vif *vif)
  {
  	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
  	struct beacon_data *beacon = NULL;
  	u8 count = 0;
  
  	rcu_read_lock();
  
  	if (sdata->vif.type == NL80211_IFTYPE_AP)
  		beacon = rcu_dereference(sdata->u.ap.beacon);
  	else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
  		beacon = rcu_dereference(sdata->u.ibss.presp);
  	else if (ieee80211_vif_is_mesh(&sdata->vif))
  		beacon = rcu_dereference(sdata->u.mesh.beacon);
  
  	if (!beacon)
  		goto unlock;
  
  	count = __ieee80211_csa_update_counter(beacon);
  
  unlock:
  	rcu_read_unlock();
  	return count;
  }
  EXPORT_SYMBOL(ieee80211_csa_update_counter);
  
  void ieee80211_csa_set_counter(struct ieee80211_vif *vif, u8 counter)
  {
  	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
  	struct beacon_data *beacon = NULL;
  
  	rcu_read_lock();
  
  	if (sdata->vif.type == NL80211_IFTYPE_AP)
  		beacon = rcu_dereference(sdata->u.ap.beacon);
  	else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
  		beacon = rcu_dereference(sdata->u.ibss.presp);
  	else if (ieee80211_vif_is_mesh(&sdata->vif))
  		beacon = rcu_dereference(sdata->u.mesh.beacon);
  
  	if (!beacon)
  		goto unlock;
  
  	if (counter < beacon->csa_current_counter)
  		beacon->csa_current_counter = counter;
  
  unlock:
  	rcu_read_unlock();
  }
  EXPORT_SYMBOL(ieee80211_csa_set_counter);
  
  bool ieee80211_csa_is_complete(struct ieee80211_vif *vif)
  {
  	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
  	struct beacon_data *beacon = NULL;
  	u8 *beacon_data;
  	size_t beacon_data_len;
  	int ret = false;
  
  	if (!ieee80211_sdata_running(sdata))
  		return false;
  
  	rcu_read_lock();
  	if (vif->type == NL80211_IFTYPE_AP) {
  		struct ieee80211_if_ap *ap = &sdata->u.ap;
  
  		beacon = rcu_dereference(ap->beacon);
  		if (WARN_ON(!beacon || !beacon->tail))
  			goto out;
  		beacon_data = beacon->tail;
  		beacon_data_len = beacon->tail_len;
  	} else if (vif->type == NL80211_IFTYPE_ADHOC) {
  		struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
  
  		beacon = rcu_dereference(ifibss->presp);
  		if (!beacon)
  			goto out;
  
  		beacon_data = beacon->head;
  		beacon_data_len = beacon->head_len;
  	} else if (vif->type == NL80211_IFTYPE_MESH_POINT) {
  		struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  
  		beacon = rcu_dereference(ifmsh->beacon);
  		if (!beacon)
  			goto out;
  
  		beacon_data = beacon->head;
  		beacon_data_len = beacon->head_len;
  	} else {
  		WARN_ON(1);
  		goto out;
  	}
  
  	if (!beacon->csa_counter_offsets[0])
  		goto out;
  
  	if (WARN_ON_ONCE(beacon->csa_counter_offsets[0] > beacon_data_len))
  		goto out;
  
  	if (beacon_data[beacon->csa_counter_offsets[0]] == 1)
  		ret = true;
   out:
  	rcu_read_unlock();
  
  	return ret;
  }
  EXPORT_SYMBOL(ieee80211_csa_is_complete);
  
  static struct sk_buff *
  __ieee80211_beacon_get(struct ieee80211_hw *hw,
  		       struct ieee80211_vif *vif,
  		       struct ieee80211_mutable_offsets *offs,
  		       bool is_template)
  {
  	struct ieee80211_local *local = hw_to_local(hw);
  	struct beacon_data *beacon = NULL;
  	struct sk_buff *skb = NULL;
  	struct ieee80211_tx_info *info;
  	struct ieee80211_sub_if_data *sdata = NULL;
  	enum nl80211_band band;
  	struct ieee80211_tx_rate_control txrc;
  	struct ieee80211_chanctx_conf *chanctx_conf;
  	int csa_off_base = 0;
  
  	rcu_read_lock();
  
  	sdata = vif_to_sdata(vif);
  	chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  
  	if (!ieee80211_sdata_running(sdata) || !chanctx_conf)
  		goto out;
  
  	if (offs)
  		memset(offs, 0, sizeof(*offs));
  
  	if (sdata->vif.type == NL80211_IFTYPE_AP) {
  		struct ieee80211_if_ap *ap = &sdata->u.ap;
  
  		beacon = rcu_dereference(ap->beacon);
  		if (beacon) {
  			if (beacon->csa_counter_offsets[0]) {
  				if (!is_template)
  					__ieee80211_csa_update_counter(beacon);
  
  				ieee80211_set_csa(sdata, beacon);
  			}
  
  			/*
  			 * headroom, head length,
  			 * tail length and maximum TIM length
  			 */
  			skb = dev_alloc_skb(local->tx_headroom +
  					    beacon->head_len +
  					    beacon->tail_len + 256 +
  					    local->hw.extra_beacon_tailroom);
  			if (!skb)
  				goto out;
  
  			skb_reserve(skb, local->tx_headroom);
  			skb_put_data(skb, beacon->head, beacon->head_len);
  
  			ieee80211_beacon_add_tim(sdata, &ap->ps, skb,
  						 is_template);
  
  			if (offs) {
  				offs->tim_offset = beacon->head_len;
  				offs->tim_length = skb->len - beacon->head_len;
  
  				/* for AP the csa offsets are from tail */
  				csa_off_base = skb->len;
  			}
  
  			if (beacon->tail)
  				skb_put_data(skb, beacon->tail,
  					     beacon->tail_len);
  		} else
  			goto out;
  	} else if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {
  		struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
  		struct ieee80211_hdr *hdr;
  
  		beacon = rcu_dereference(ifibss->presp);
  		if (!beacon)
  			goto out;
  
  		if (beacon->csa_counter_offsets[0]) {
  			if (!is_template)
  				__ieee80211_csa_update_counter(beacon);
  
  			ieee80211_set_csa(sdata, beacon);
  		}
  
  		skb = dev_alloc_skb(local->tx_headroom + beacon->head_len +
  				    local->hw.extra_beacon_tailroom);
  		if (!skb)
  			goto out;
  		skb_reserve(skb, local->tx_headroom);
  		skb_put_data(skb, beacon->head, beacon->head_len);
  
  		hdr = (struct ieee80211_hdr *) skb->data;
  		hdr->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  						 IEEE80211_STYPE_BEACON);
  	} else if (ieee80211_vif_is_mesh(&sdata->vif)) {
  		struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
  
  		beacon = rcu_dereference(ifmsh->beacon);
  		if (!beacon)
  			goto out;
  
  		if (beacon->csa_counter_offsets[0]) {
  			if (!is_template)
  				/* TODO: For mesh csa_counter is in TU, so
  				 * decrementing it by one isn't correct, but
  				 * for now we leave it consistent with overall
  				 * mac80211's behavior.
  				 */
  				__ieee80211_csa_update_counter(beacon);
  
  			ieee80211_set_csa(sdata, beacon);
  		}
  
  		if (ifmsh->sync_ops)
  			ifmsh->sync_ops->adjust_tsf(sdata, beacon);
  
  		skb = dev_alloc_skb(local->tx_headroom +
  				    beacon->head_len +
  				    256 + /* TIM IE */
  				    beacon->tail_len +
  				    local->hw.extra_beacon_tailroom);
  		if (!skb)
  			goto out;
  		skb_reserve(skb, local->tx_headroom);
  		skb_put_data(skb, beacon->head, beacon->head_len);
  		ieee80211_beacon_add_tim(sdata, &ifmsh->ps, skb, is_template);
  
  		if (offs) {
  			offs->tim_offset = beacon->head_len;
  			offs->tim_length = skb->len - beacon->head_len;
  		}
  
  		skb_put_data(skb, beacon->tail, beacon->tail_len);
  	} else {
  		WARN_ON(1);
  		goto out;
  	}
  
  	/* CSA offsets */
  	if (offs && beacon) {
  		int i;
  
  		for (i = 0; i < IEEE80211_MAX_CSA_COUNTERS_NUM; i++) {
  			u16 csa_off = beacon->csa_counter_offsets[i];
  
  			if (!csa_off)
  				continue;
  
  			offs->csa_counter_offs[i] = csa_off_base + csa_off;
  		}
  	}
  
  	band = chanctx_conf->def.chan->band;
  
  	info = IEEE80211_SKB_CB(skb);
  
  	info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
  	info->flags |= IEEE80211_TX_CTL_NO_ACK;
  	info->band = band;
  
  	memset(&txrc, 0, sizeof(txrc));
  	txrc.hw = hw;
  	txrc.sband = local->hw.wiphy->bands[band];
  	txrc.bss_conf = &sdata->vif.bss_conf;
  	txrc.skb = skb;
  	txrc.reported_rate.idx = -1;
  	txrc.rate_idx_mask = sdata->rc_rateidx_mask[band];
  	txrc.bss = true;
  	rate_control_get_rate(sdata, NULL, &txrc);
  
  	info->control.vif = vif;
  
  	info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT |
  			IEEE80211_TX_CTL_ASSIGN_SEQ |
  			IEEE80211_TX_CTL_FIRST_FRAGMENT;
   out:
  	rcu_read_unlock();
  	return skb;
  
  }
  
  struct sk_buff *
  ieee80211_beacon_get_template(struct ieee80211_hw *hw,
  			      struct ieee80211_vif *vif,
  			      struct ieee80211_mutable_offsets *offs)
  {
  	return __ieee80211_beacon_get(hw, vif, offs, true);
  }
  EXPORT_SYMBOL(ieee80211_beacon_get_template);
  
  struct sk_buff *ieee80211_beacon_get_tim(struct ieee80211_hw *hw,
  					 struct ieee80211_vif *vif,
  					 u16 *tim_offset, u16 *tim_length)
  {
  	struct ieee80211_mutable_offsets offs = {};
  	struct sk_buff *bcn = __ieee80211_beacon_get(hw, vif, &offs, false);
  	struct sk_buff *copy;
  	struct ieee80211_supported_band *sband;
  	int shift;
  
  	if (!bcn)
  		return bcn;
  
  	if (tim_offset)
  		*tim_offset = offs.tim_offset;
  
  	if (tim_length)
  		*tim_length = offs.tim_length;
  
  	if (ieee80211_hw_check(hw, BEACON_TX_STATUS) ||
  	    !hw_to_local(hw)->monitors)
  		return bcn;
  
  	/* send a copy to monitor interfaces */
  	copy = skb_copy(bcn, GFP_ATOMIC);
  	if (!copy)
  		return bcn;
  
  	shift = ieee80211_vif_get_shift(vif);
  	sband = ieee80211_get_sband(vif_to_sdata(vif));
  	if (!sband)
  		return bcn;
  
  	ieee80211_tx_monitor(hw_to_local(hw), copy, sband, 1, shift, false);
  
  	return bcn;
  }
  EXPORT_SYMBOL(ieee80211_beacon_get_tim);
  
  struct sk_buff *ieee80211_proberesp_get(struct ieee80211_hw *hw,
  					struct ieee80211_vif *vif)
  {
  	struct ieee80211_if_ap *ap = NULL;
  	struct sk_buff *skb = NULL;
  	struct probe_resp *presp = NULL;
  	struct ieee80211_hdr *hdr;
  	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
  
  	if (sdata->vif.type != NL80211_IFTYPE_AP)
  		return NULL;
  
  	rcu_read_lock();
  
  	ap = &sdata->u.ap;
  	presp = rcu_dereference(ap->probe_resp);
  	if (!presp)
  		goto out;
  
  	skb = dev_alloc_skb(presp->len);
  	if (!skb)
  		goto out;
  
  	skb_put_data(skb, presp->data, presp->len);
  
  	hdr = (struct ieee80211_hdr *) skb->data;
  	memset(hdr->addr1, 0, sizeof(hdr->addr1));
  
  out:
  	rcu_read_unlock();
  	return skb;
  }
  EXPORT_SYMBOL(ieee80211_proberesp_get);
  
  struct sk_buff *ieee80211_pspoll_get(struct ieee80211_hw *hw,
  				     struct ieee80211_vif *vif)
  {
  	struct ieee80211_sub_if_data *sdata;
  	struct ieee80211_if_managed *ifmgd;
  	struct ieee80211_pspoll *pspoll;
  	struct ieee80211_local *local;
  	struct sk_buff *skb;
  
  	if (WARN_ON(vif->type != NL80211_IFTYPE_STATION))
  		return NULL;
  
  	sdata = vif_to_sdata(vif);
  	ifmgd = &sdata->u.mgd;
  	local = sdata->local;
  
  	skb = dev_alloc_skb(local->hw.extra_tx_headroom + sizeof(*pspoll));
  	if (!skb)
  		return NULL;
  
  	skb_reserve(skb, local->hw.extra_tx_headroom);
  
  	pspoll = skb_put_zero(skb, sizeof(*pspoll));
  	pspoll->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
  					    IEEE80211_STYPE_PSPOLL);
  	pspoll->aid = cpu_to_le16(ifmgd->aid);
  
  	/* aid in PS-Poll has its two MSBs each set to 1 */
  	pspoll->aid |= cpu_to_le16(1 << 15 | 1 << 14);
  
  	memcpy(pspoll->bssid, ifmgd->bssid, ETH_ALEN);
  	memcpy(pspoll->ta, vif->addr, ETH_ALEN);
  
  	return skb;
  }
  EXPORT_SYMBOL(ieee80211_pspoll_get);
  
  struct sk_buff *ieee80211_nullfunc_get(struct ieee80211_hw *hw,
  				       struct ieee80211_vif *vif,
  				       bool qos_ok)
  {
  	struct ieee80211_hdr_3addr *nullfunc;
  	struct ieee80211_sub_if_data *sdata;
  	struct ieee80211_if_managed *ifmgd;
  	struct ieee80211_local *local;
  	struct sk_buff *skb;
  	bool qos = false;
  
  	if (WARN_ON(vif->type != NL80211_IFTYPE_STATION))
  		return NULL;
  
  	sdata = vif_to_sdata(vif);
  	ifmgd = &sdata->u.mgd;
  	local = sdata->local;
  
  	if (qos_ok) {
  		struct sta_info *sta;
  
  		rcu_read_lock();
  		sta = sta_info_get(sdata, ifmgd->bssid);
  		qos = sta && sta->sta.wme;
  		rcu_read_unlock();
  	}
  
  	skb = dev_alloc_skb(local->hw.extra_tx_headroom +
  			    sizeof(*nullfunc) + 2);
  	if (!skb)
  		return NULL;
  
  	skb_reserve(skb, local->hw.extra_tx_headroom);
  
  	nullfunc = skb_put_zero(skb, sizeof(*nullfunc));
  	nullfunc->frame_control = cpu_to_le16(IEEE80211_FTYPE_DATA |
  					      IEEE80211_STYPE_NULLFUNC |
  					      IEEE80211_FCTL_TODS);
  	if (qos) {
  		__le16 qos = cpu_to_le16(7);
  
  		BUILD_BUG_ON((IEEE80211_STYPE_QOS_NULLFUNC |
  			      IEEE80211_STYPE_NULLFUNC) !=
  			     IEEE80211_STYPE_QOS_NULLFUNC);
  		nullfunc->frame_control |=
  			cpu_to_le16(IEEE80211_STYPE_QOS_NULLFUNC);
  		skb->priority = 7;
  		skb_set_queue_mapping(skb, IEEE80211_AC_VO);
  		skb_put_data(skb, &qos, sizeof(qos));
  	}
  
  	memcpy(nullfunc->addr1, ifmgd->bssid, ETH_ALEN);
  	memcpy(nullfunc->addr2, vif->addr, ETH_ALEN);
  	memcpy(nullfunc->addr3, ifmgd->bssid, ETH_ALEN);
  
  	return skb;
  }
  EXPORT_SYMBOL(ieee80211_nullfunc_get);
  
  struct sk_buff *ieee80211_probereq_get(struct ieee80211_hw *hw,
  				       const u8 *src_addr,
  				       const u8 *ssid, size_t ssid_len,
  				       size_t tailroom)
  {
  	struct ieee80211_local *local = hw_to_local(hw);
  	struct ieee80211_hdr_3addr *hdr;
  	struct sk_buff *skb;
  	size_t ie_ssid_len;
  	u8 *pos;
  
  	ie_ssid_len = 2 + ssid_len;
  
  	skb = dev_alloc_skb(local->hw.extra_tx_headroom + sizeof(*hdr) +
  			    ie_ssid_len + tailroom);
  	if (!skb)
  		return NULL;
  
  	skb_reserve(skb, local->hw.extra_tx_headroom);
  
  	hdr = skb_put_zero(skb, sizeof(*hdr));
  	hdr->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
  					 IEEE80211_STYPE_PROBE_REQ);
  	eth_broadcast_addr(hdr->addr1);
  	memcpy(hdr->addr2, src_addr, ETH_ALEN);
  	eth_broadcast_addr(hdr->addr3);
  
  	pos = skb_put(skb, ie_ssid_len);
  	*pos++ = WLAN_EID_SSID;
  	*pos++ = ssid_len;
  	if (ssid_len)
  		memcpy(pos, ssid, ssid_len);
  	pos += ssid_len;
  
  	return skb;
  }
  EXPORT_SYMBOL(ieee80211_probereq_get);
  
  void ieee80211_rts_get(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
  		       const void *frame, size_t frame_len,
  		       const struct ieee80211_tx_info *frame_txctl,
  		       struct ieee80211_rts *rts)
  {
  	const struct ieee80211_hdr *hdr = frame;
  
  	rts->frame_control =
  	    cpu_to_le16(IEEE80211_FTYPE_CTL | IEEE80211_STYPE_RTS);
  	rts->duration = ieee80211_rts_duration(hw, vif, frame_len,
  					       frame_txctl);
  	memcpy(rts->ra, hdr->addr1, sizeof(rts->ra));
  	memcpy(rts->ta, hdr->addr2, sizeof(rts->ta));
  }
  EXPORT_SYMBOL(ieee80211_rts_get);
  
  void ieee80211_ctstoself_get(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
  			     const void *frame, size_t frame_len,
  			     const struct ieee80211_tx_info *frame_txctl,
  			     struct ieee80211_cts *cts)
  {
  	const struct ieee80211_hdr *hdr = frame;
  
  	cts->frame_control =
  	    cpu_to_le16(IEEE80211_FTYPE_CTL | IEEE80211_STYPE_CTS);
  	cts->duration = ieee80211_ctstoself_duration(hw, vif,
  						     frame_len, frame_txctl);
  	memcpy(cts->ra, hdr->addr1, sizeof(cts->ra));
  }
  EXPORT_SYMBOL(ieee80211_ctstoself_get);
  
  struct sk_buff *
  ieee80211_get_buffered_bc(struct ieee80211_hw *hw,
  			  struct ieee80211_vif *vif)
  {
  	struct ieee80211_local *local = hw_to_local(hw);
  	struct sk_buff *skb = NULL;
  	struct ieee80211_tx_data tx;
  	struct ieee80211_sub_if_data *sdata;
  	struct ps_data *ps;
  	struct ieee80211_tx_info *info;
  	struct ieee80211_chanctx_conf *chanctx_conf;
  
  	sdata = vif_to_sdata(vif);
  
  	rcu_read_lock();
  	chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
  
  	if (!chanctx_conf)
  		goto out;
  
  	if (sdata->vif.type == NL80211_IFTYPE_AP) {
  		struct beacon_data *beacon =
  				rcu_dereference(sdata->u.ap.beacon);
  
  		if (!beacon || !beacon->head)
  			goto out;
  
  		ps = &sdata->u.ap.ps;
  	} else if (ieee80211_vif_is_mesh(&sdata->vif)) {
  		ps = &sdata->u.mesh.ps;
  	} else {
  		goto out;
  	}
  
  	if (ps->dtim_count != 0 || !ps->dtim_bc_mc)
  		goto out; /* send buffered bc/mc only after DTIM beacon */
  
  	while (1) {
  		skb = skb_dequeue(&ps->bc_buf);
  		if (!skb)
  			goto out;
  		local->total_ps_buffered--;
  
  		if (!skb_queue_empty(&ps->bc_buf) && skb->len >= 2) {
  			struct ieee80211_hdr *hdr =
  				(struct ieee80211_hdr *) skb->data;
  			/* more buffered multicast/broadcast frames ==> set
  			 * MoreData flag in IEEE 802.11 header to inform PS
  			 * STAs */
  			hdr->frame_control |=
  				cpu_to_le16(IEEE80211_FCTL_MOREDATA);
  		}
  
  		if (sdata->vif.type == NL80211_IFTYPE_AP)
  			sdata = IEEE80211_DEV_TO_SUB_IF(skb->dev);
  		if (!ieee80211_tx_prepare(sdata, &tx, NULL, skb))
  			break;
  		ieee80211_free_txskb(hw, skb);
  	}
  
  	info = IEEE80211_SKB_CB(skb);
  
  	tx.flags |= IEEE80211_TX_PS_BUFFERED;
  	info->band = chanctx_conf->def.chan->band;
  
  	if (invoke_tx_handlers(&tx))
  		skb = NULL;
   out:
  	rcu_read_unlock();
  
  	return skb;
  }
  EXPORT_SYMBOL(ieee80211_get_buffered_bc);
  
  int ieee80211_reserve_tid(struct ieee80211_sta *pubsta, u8 tid)
  {
  	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
  	struct ieee80211_sub_if_data *sdata = sta->sdata;
  	struct ieee80211_local *local = sdata->local;
  	int ret;
  	u32 queues;
  
  	lockdep_assert_held(&local->sta_mtx);
  
  	/* only some cases are supported right now */
  	switch (sdata->vif.type) {
  	case NL80211_IFTYPE_STATION:
  	case NL80211_IFTYPE_AP:
  	case NL80211_IFTYPE_AP_VLAN:
  		break;
  	default:
  		WARN_ON(1);
  		return -EINVAL;
  	}
  
  	if (WARN_ON(tid >= IEEE80211_NUM_UPS))
  		return -EINVAL;
  
  	if (sta->reserved_tid == tid) {
  		ret = 0;
  		goto out;
  	}
  
  	if (sta->reserved_tid != IEEE80211_TID_UNRESERVED) {
  		sdata_err(sdata, "TID reservation already active\n");
  		ret = -EALREADY;
  		goto out;
  	}
  
  	ieee80211_stop_vif_queues(sdata->local, sdata,
  				  IEEE80211_QUEUE_STOP_REASON_RESERVE_TID);
  
  	synchronize_net();
  
  	/* Tear down BA sessions so we stop aggregating on this TID */
  	if (ieee80211_hw_check(&local->hw, AMPDU_AGGREGATION)) {
  		set_sta_flag(sta, WLAN_STA_BLOCK_BA);
  		__ieee80211_stop_tx_ba_session(sta, tid,
  					       AGG_STOP_LOCAL_REQUEST);
  	}
  
  	queues = BIT(sdata->vif.hw_queue[ieee802_1d_to_ac[tid]]);
  	__ieee80211_flush_queues(local, sdata, queues, false);
  
  	sta->reserved_tid = tid;
  
  	ieee80211_wake_vif_queues(local, sdata,
  				  IEEE80211_QUEUE_STOP_REASON_RESERVE_TID);
  
  	if (ieee80211_hw_check(&local->hw, AMPDU_AGGREGATION))
  		clear_sta_flag(sta, WLAN_STA_BLOCK_BA);
  
  	ret = 0;
   out:
  	return ret;
  }
  EXPORT_SYMBOL(ieee80211_reserve_tid);
  
  void ieee80211_unreserve_tid(struct ieee80211_sta *pubsta, u8 tid)
  {
  	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
  	struct ieee80211_sub_if_data *sdata = sta->sdata;
  
  	lockdep_assert_held(&sdata->local->sta_mtx);
  
  	/* only some cases are supported right now */
  	switch (sdata->vif.type) {
  	case NL80211_IFTYPE_STATION:
  	case NL80211_IFTYPE_AP:
  	case NL80211_IFTYPE_AP_VLAN:
  		break;
  	default:
  		WARN_ON(1);
  		return;
  	}
  
  	if (tid != sta->reserved_tid) {
  		sdata_err(sdata, "TID to unreserve (%d) isn't reserved\n", tid);
  		return;
  	}
  
  	sta->reserved_tid = IEEE80211_TID_UNRESERVED;
  }
  EXPORT_SYMBOL(ieee80211_unreserve_tid);
  
  void __ieee80211_tx_skb_tid_band(struct ieee80211_sub_if_data *sdata,
  				 struct sk_buff *skb, int tid,
  				 enum nl80211_band band)
  {
  	int ac = ieee80211_ac_from_tid(tid);
  
  	skb_reset_mac_header(skb);
  	skb_set_queue_mapping(skb, ac);
  	skb->priority = tid;
  
  	skb->dev = sdata->dev;
  
  	/*
  	 * The other path calling ieee80211_xmit is from the tasklet,
  	 * and while we can handle concurrent transmissions locking
  	 * requirements are that we do not come into tx with bhs on.
  	 */
  	local_bh_disable();
  	IEEE80211_SKB_CB(skb)->band = band;
  	ieee80211_xmit(sdata, NULL, skb);
  	local_bh_enable();
  }
  
  int ieee80211_tx_control_port(struct wiphy *wiphy, struct net_device *dev,
  			      const u8 *buf, size_t len,
  			      const u8 *dest, __be16 proto, bool unencrypted)
  {
  	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
  	struct ieee80211_local *local = sdata->local;
  	struct sk_buff *skb;
  	struct ethhdr *ehdr;
  	u32 flags;
  
  	/* Only accept CONTROL_PORT_PROTOCOL configured in CONNECT/ASSOCIATE
  	 * or Pre-Authentication
  	 */
  	if (proto != sdata->control_port_protocol &&
  	    proto != cpu_to_be16(ETH_P_PREAUTH))
  		return -EINVAL;
  
  	if (unencrypted)
  		flags = IEEE80211_TX_INTFL_DONT_ENCRYPT;
  	else
  		flags = 0;
  
  	skb = dev_alloc_skb(local->hw.extra_tx_headroom +
  			    sizeof(struct ethhdr) + len);
  	if (!skb)
  		return -ENOMEM;
  
  	skb_reserve(skb, local->hw.extra_tx_headroom + sizeof(struct ethhdr));
  
  	skb_put_data(skb, buf, len);
  
  	ehdr = skb_push(skb, sizeof(struct ethhdr));
  	memcpy(ehdr->h_dest, dest, ETH_ALEN);
  	memcpy(ehdr->h_source, sdata->vif.addr, ETH_ALEN);
  	ehdr->h_proto = proto;
  
  	skb->dev = dev;
  	skb->protocol = htons(ETH_P_802_3);
  	skb_reset_network_header(skb);
  	skb_reset_mac_header(skb);
  
  	__ieee80211_subif_start_xmit(skb, skb->dev, flags);
  
  	return 0;
  }
  