ieee80211_rx_h_ctrl(struct ieee80211_rx_data *rx, struct sk_buff_head *frames)
{
	struct sk_buff *skb = rx->skb;
	struct ieee80211_bar *bar = (struct ieee80211_bar *)skb->data;
	struct tid_ampdu_rx *tid_agg_rx;
	u16 start_seq_num;
	u16 tid;

	if (likely(!ieee80211_is_ctl(bar->frame_control)))
		return RX_CONTINUE;

	if (ieee80211_is_back_req(bar->frame_control)) {
		struct {
			__le16 control, start_seq_num;
		} __packed bar_data;
		struct ieee80211_event event = {
			.type = BAR_RX_EVENT,
		};

		if (!rx->sta)
			return RX_DROP_MONITOR;

		if (skb_copy_bits(skb, offsetof(struct ieee80211_bar, control),
				  &bar_data, sizeof(bar_data)))
			return RX_DROP_MONITOR;

		tid = le16_to_cpu(bar_data.control) >> 12;

		if (!test_bit(tid, rx->sta->ampdu_mlme.agg_session_valid) &&
		    !test_and_set_bit(tid, rx->sta->ampdu_mlme.unexpected_agg))
			ieee80211_send_delba(rx->sdata, rx->sta->sta.addr, tid,
					     WLAN_BACK_RECIPIENT,
					     WLAN_REASON_QSTA_REQUIRE_SETUP);

		tid_agg_rx = rcu_dereference(rx->sta->ampdu_mlme.tid_rx[tid]);
		if (!tid_agg_rx)
			return RX_DROP_MONITOR;

		start_seq_num = le16_to_cpu(bar_data.start_seq_num) >> 4;
		event.u.ba.tid = tid;
		event.u.ba.ssn = start_seq_num;
		event.u.ba.sta = &rx->sta->sta;

		/* reset session timer */
		if (tid_agg_rx->timeout)
			mod_timer(&tid_agg_rx->session_timer,
				  TU_TO_EXP_TIME(tid_agg_rx->timeout));

		spin_lock(&tid_agg_rx->reorder_lock);
		/* release stored frames up to start of BAR */
		ieee80211_release_reorder_frames(rx->sdata, tid_agg_rx,
						 start_seq_num, frames);
		spin_unlock(&tid_agg_rx->reorder_lock);

		drv_event_callback(rx->local, rx->sdata, &event);

		kfree_skb(skb);
		return RX_QUEUED;
	}

	/*
	 * After this point, we only want management frames,
	 * so we can drop all remaining control frames to
	 * cooked monitor interfaces.
	 */
	return RX_DROP_MONITOR;
}
Unknown