__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->cntdwn_counter_offsets[0]) {
				if (!is_template)
					ieee80211_beacon_update_cntdwn(vif);

				ieee80211_set_beacon_cntdwn(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);

			if (ieee80211_beacon_protect(skb, local, sdata) < 0)
				goto out;
		} 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->cntdwn_counter_offsets[0]) {
			if (!is_template)
				__ieee80211_beacon_update_cntdwn(beacon);

			ieee80211_set_beacon_cntdwn(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->cntdwn_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_beacon_update_cntdwn(beacon);

			ieee80211_set_beacon_cntdwn(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_CNTDWN_COUNTERS_NUM; i++) {
			u16 csa_off = beacon->cntdwn_counter_offsets[i];

			if (!csa_off)
				continue;

			offs->cntdwn_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;
	if (sdata->beacon_rate_set && sdata->beacon_rateidx_mask[band])
		txrc.rate_idx_mask = sdata->beacon_rateidx_mask[band];
	else
		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;

}
__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->cntdwn_counter_offsets[0]) {
				if (!is_template)
					ieee80211_beacon_update_cntdwn(vif);

				ieee80211_set_beacon_cntdwn(sdata, beacon);
			}

			 
			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;

				 
				csa_off_base = skb->len;
			}

			if (beacon->tail)
				skb_put_data(skb, beacon->tail,
					     beacon->tail_len);

			if (ieee80211_beacon_protect(skb, local, sdata) < 0)
				goto out;
		} 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->cntdwn_counter_offsets[0]) {
			if (!is_template)
				__ieee80211_beacon_update_cntdwn(beacon);

			ieee80211_set_beacon_cntdwn(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->cntdwn_counter_offsets[0]) {
			if (!is_template)
				 
				__ieee80211_beacon_update_cntdwn(beacon);

			ieee80211_set_beacon_cntdwn(sdata, beacon);
		}

		if (ifmsh->sync_ops)
			ifmsh->sync_ops->adjust_tsf(sdata, beacon);

		skb = dev_alloc_skb(local->tx_headroom +
				    beacon->head_len +
				    256 +  
				    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;
	}

	 
	if (offs && beacon) {
		int i;

		for (i = 0; i < IEEE80211_MAX_CNTDWN_COUNTERS_NUM; i++) {
			u16 csa_off = beacon->cntdwn_counter_offsets[i];

			if (!csa_off)
				continue;

			offs->cntdwn_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;
	if (sdata->beacon_rate_set && sdata->beacon_rateidx_mask[band])
		txrc.rate_idx_mask = sdata->beacon_rateidx_mask[band];
	else
		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;

}