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33 results

rx.c

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  • rx.c 94.75 KiB
    /*
     * Copyright 2002-2005, Instant802 Networks, Inc.
     * Copyright 2005-2006, Devicescape Software, Inc.
     * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
     * Copyright 2007-2010	Johannes Berg <johannes@sipsolutions.net>
     *
     * This program is free software; you can redistribute it and/or modify
     * it under the terms of the GNU General Public License version 2 as
     * published by the Free Software Foundation.
     */
    
    #include <linux/jiffies.h>
    #include <linux/slab.h>
    #include <linux/kernel.h>
    #include <linux/skbuff.h>
    #include <linux/netdevice.h>
    #include <linux/etherdevice.h>
    #include <linux/rcupdate.h>
    #include <linux/export.h>
    #include <net/mac80211.h>
    #include <net/ieee80211_radiotap.h>
    #include <asm/unaligned.h>
    
    #include "ieee80211_i.h"
    #include "driver-ops.h"
    #include "led.h"
    #include "mesh.h"
    #include "wep.h"
    #include "wpa.h"
    #include "tkip.h"
    #include "wme.h"
    #include "rate.h"
    
    /*
     * monitor mode reception
     *
     * This function cleans up the SKB, i.e. it removes all the stuff
     * only useful for monitoring.
     */
    static struct sk_buff *remove_monitor_info(struct ieee80211_local *local,
    					   struct sk_buff *skb)
    {
    	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
    		if (likely(skb->len > FCS_LEN))
    			__pskb_trim(skb, skb->len - FCS_LEN);
    		else {
    			/* driver bug */
    			WARN_ON(1);
    			dev_kfree_skb(skb);
    			return NULL;
    		}
    	}
    
    	return skb;
    }
    
    static inline int should_drop_frame(struct sk_buff *skb, int present_fcs_len)
    {
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
    	struct ieee80211_hdr *hdr;
    
    	hdr = (void *)(skb->data);
    
    	if (status->flag & (RX_FLAG_FAILED_FCS_CRC |
    			    RX_FLAG_FAILED_PLCP_CRC |
    			    RX_FLAG_AMPDU_IS_ZEROLEN))
    		return 1;
    	if (unlikely(skb->len < 16 + present_fcs_len))
    		return 1;
    	if (ieee80211_is_ctl(hdr->frame_control) &&
    	    !ieee80211_is_pspoll(hdr->frame_control) &&
    	    !ieee80211_is_back_req(hdr->frame_control))
    		return 1;
    	return 0;
    }
    
    static int
    ieee80211_rx_radiotap_space(struct ieee80211_local *local,
    			    struct ieee80211_rx_status *status)
    {
    	int len;
    
    	/* always present fields */
    	len = sizeof(struct ieee80211_radiotap_header) + 8;
    
    	/* allocate extra bitmaps */
    	if (status->chains)
    		len += 4 * hweight8(status->chains);
    
    	if (ieee80211_have_rx_timestamp(status)) {
    		len = ALIGN(len, 8);
    		len += 8;
    	}
    	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
    		len += 1;
    
    	/* antenna field, if we don't have per-chain info */
    	if (!status->chains)
    		len += 1;
    
    	/* padding for RX_FLAGS if necessary */
    	len = ALIGN(len, 2);
    
    	if (status->flag & RX_FLAG_HT) /* HT info */
    		len += 3;
    
    	if (status->flag & RX_FLAG_AMPDU_DETAILS) {
    		len = ALIGN(len, 4);
    		len += 8;
    	}
    
    	if (status->flag & RX_FLAG_VHT) {
    		len = ALIGN(len, 2);
    		len += 12;
    	}
    
    	if (status->chains) {
    		/* antenna and antenna signal fields */
    		len += 2 * hweight8(status->chains);
    	}
    
    	return len;
    }
    
    /*
     * ieee80211_add_rx_radiotap_header - add radiotap header
     *
     * add a radiotap header containing all the fields which the hardware provided.
     */
    static void
    ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
    				 struct sk_buff *skb,
    				 struct ieee80211_rate *rate,
    				 int rtap_len, bool has_fcs)
    {
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
    	struct ieee80211_radiotap_header *rthdr;
    	unsigned char *pos;
    	__le32 *it_present;
    	u32 it_present_val;
    	u16 rx_flags = 0;
    	u16 channel_flags = 0;
    	int mpdulen, chain;
    	unsigned long chains = status->chains;
    
    	mpdulen = skb->len;
    	if (!(has_fcs && (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)))
    		mpdulen += FCS_LEN;
    
    	rthdr = (struct ieee80211_radiotap_header *)skb_push(skb, rtap_len);
    	memset(rthdr, 0, rtap_len);
    	it_present = &rthdr->it_present;
    
    	/* radiotap header, set always present flags */
    	rthdr->it_len = cpu_to_le16(rtap_len);
    	it_present_val = BIT(IEEE80211_RADIOTAP_FLAGS) |
    			 BIT(IEEE80211_RADIOTAP_CHANNEL) |
    			 BIT(IEEE80211_RADIOTAP_RX_FLAGS);
    
    	if (!status->chains)
    		it_present_val |= BIT(IEEE80211_RADIOTAP_ANTENNA);
    
    	for_each_set_bit(chain, &chains, IEEE80211_MAX_CHAINS) {
    		it_present_val |=
    			BIT(IEEE80211_RADIOTAP_EXT) |
    			BIT(IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE);
    		put_unaligned_le32(it_present_val, it_present);
    		it_present++;
    		it_present_val = BIT(IEEE80211_RADIOTAP_ANTENNA) |
    				 BIT(IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
    	}
    
    	put_unaligned_le32(it_present_val, it_present);
    
    	pos = (void *)(it_present + 1);
    
    	/* the order of the following fields is important */
    
    	/* IEEE80211_RADIOTAP_TSFT */
    	if (ieee80211_have_rx_timestamp(status)) {
    		/* padding */
    		while ((pos - (u8 *)rthdr) & 7)
    			*pos++ = 0;
    		put_unaligned_le64(
    			ieee80211_calculate_rx_timestamp(local, status,
    							 mpdulen, 0),
    			pos);
    		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
    		pos += 8;
    	}
    
    	/* IEEE80211_RADIOTAP_FLAGS */
    	if (has_fcs && (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS))
    		*pos |= IEEE80211_RADIOTAP_F_FCS;
    	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
    		*pos |= IEEE80211_RADIOTAP_F_BADFCS;
    	if (status->flag & RX_FLAG_SHORTPRE)
    		*pos |= IEEE80211_RADIOTAP_F_SHORTPRE;
    	pos++;
    
    	/* IEEE80211_RADIOTAP_RATE */
    	if (!rate || status->flag & (RX_FLAG_HT | RX_FLAG_VHT)) {
    		/*
    		 * Without rate information don't add it. If we have,
    		 * MCS information is a separate field in radiotap,
    		 * added below. The byte here is needed as padding
    		 * for the channel though, so initialise it to 0.
    		 */
    		*pos = 0;
    	} else {
    		int shift = 0;
    		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
    		if (status->flag & RX_FLAG_10MHZ)
    			shift = 1;
    		else if (status->flag & RX_FLAG_5MHZ)
    			shift = 2;
    		*pos = DIV_ROUND_UP(rate->bitrate, 5 * (1 << shift));
    	}
    	pos++;
    
    	/* IEEE80211_RADIOTAP_CHANNEL */
    	put_unaligned_le16(status->freq, pos);
    	pos += 2;
    	if (status->flag & RX_FLAG_10MHZ)
    		channel_flags |= IEEE80211_CHAN_HALF;
    	else if (status->flag & RX_FLAG_5MHZ)
    		channel_flags |= IEEE80211_CHAN_QUARTER;
    
    	if (status->band == IEEE80211_BAND_5GHZ)
    		channel_flags |= IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ;
    	else if (status->flag & (RX_FLAG_HT | RX_FLAG_VHT))
    		channel_flags |= IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ;
    	else if (rate && rate->flags & IEEE80211_RATE_ERP_G)
    		channel_flags |= IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ;
    	else if (rate)
    		channel_flags |= IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ;
    	else
    		channel_flags |= IEEE80211_CHAN_2GHZ;
    	put_unaligned_le16(channel_flags, pos);
    	pos += 2;
    
    	/* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */
    	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM &&
    	    !(status->flag & RX_FLAG_NO_SIGNAL_VAL)) {
    		*pos = status->signal;
    		rthdr->it_present |=
    			cpu_to_le32(1 << IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
    		pos++;
    	}
    
    	/* IEEE80211_RADIOTAP_LOCK_QUALITY is missing */
    
    	if (!status->chains) {
    		/* IEEE80211_RADIOTAP_ANTENNA */
    		*pos = status->antenna;
    		pos++;
    	}
    
    	/* IEEE80211_RADIOTAP_DB_ANTNOISE is not used */
    
    	/* IEEE80211_RADIOTAP_RX_FLAGS */
    	/* ensure 2 byte alignment for the 2 byte field as required */
    	if ((pos - (u8 *)rthdr) & 1)
    		*pos++ = 0;
    	if (status->flag & RX_FLAG_FAILED_PLCP_CRC)
    		rx_flags |= IEEE80211_RADIOTAP_F_RX_BADPLCP;
    	put_unaligned_le16(rx_flags, pos);
    	pos += 2;
    
    	if (status->flag & RX_FLAG_HT) {
    		unsigned int stbc;
    
    		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
    		*pos++ = local->hw.radiotap_mcs_details;
    		*pos = 0;
    		if (status->flag & RX_FLAG_SHORT_GI)
    			*pos |= IEEE80211_RADIOTAP_MCS_SGI;
    		if (status->flag & RX_FLAG_40MHZ)
    			*pos |= IEEE80211_RADIOTAP_MCS_BW_40;
    		if (status->flag & RX_FLAG_HT_GF)
    			*pos |= IEEE80211_RADIOTAP_MCS_FMT_GF;
    		if (status->flag & RX_FLAG_LDPC)
    			*pos |= IEEE80211_RADIOTAP_MCS_FEC_LDPC;
    		stbc = (status->flag & RX_FLAG_STBC_MASK) >> RX_FLAG_STBC_SHIFT;
    		*pos |= stbc << IEEE80211_RADIOTAP_MCS_STBC_SHIFT;
    		pos++;
    		*pos++ = status->rate_idx;
    	}
    
    	if (status->flag & RX_FLAG_AMPDU_DETAILS) {
    		u16 flags = 0;
    
    		/* ensure 4 byte alignment */
    		while ((pos - (u8 *)rthdr) & 3)
    			pos++;
    		rthdr->it_present |=
    			cpu_to_le32(1 << IEEE80211_RADIOTAP_AMPDU_STATUS);
    		put_unaligned_le32(status->ampdu_reference, pos);
    		pos += 4;
    		if (status->flag & RX_FLAG_AMPDU_REPORT_ZEROLEN)
    			flags |= IEEE80211_RADIOTAP_AMPDU_REPORT_ZEROLEN;
    		if (status->flag & RX_FLAG_AMPDU_IS_ZEROLEN)
    			flags |= IEEE80211_RADIOTAP_AMPDU_IS_ZEROLEN;
    		if (status->flag & RX_FLAG_AMPDU_LAST_KNOWN)
    			flags |= IEEE80211_RADIOTAP_AMPDU_LAST_KNOWN;
    		if (status->flag & RX_FLAG_AMPDU_IS_LAST)
    			flags |= IEEE80211_RADIOTAP_AMPDU_IS_LAST;
    		if (status->flag & RX_FLAG_AMPDU_DELIM_CRC_ERROR)
    			flags |= IEEE80211_RADIOTAP_AMPDU_DELIM_CRC_ERR;
    		if (status->flag & RX_FLAG_AMPDU_DELIM_CRC_KNOWN)
    			flags |= IEEE80211_RADIOTAP_AMPDU_DELIM_CRC_KNOWN;
    		put_unaligned_le16(flags, pos);
    		pos += 2;
    		if (status->flag & RX_FLAG_AMPDU_DELIM_CRC_KNOWN)
    			*pos++ = status->ampdu_delimiter_crc;
    		else
    			*pos++ = 0;
    		*pos++ = 0;
    	}
    
    	if (status->flag & RX_FLAG_VHT) {
    		u16 known = local->hw.radiotap_vht_details;
    
    		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_VHT);
    		/* known field - how to handle 80+80? */
    		if (status->vht_flag & RX_VHT_FLAG_80P80MHZ)
    			known &= ~IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH;
    		put_unaligned_le16(known, pos);
    		pos += 2;
    		/* flags */
    		if (status->flag & RX_FLAG_SHORT_GI)
    			*pos |= IEEE80211_RADIOTAP_VHT_FLAG_SGI;
    		/* in VHT, STBC is binary */
    		if (status->flag & RX_FLAG_STBC_MASK)
    			*pos |= IEEE80211_RADIOTAP_VHT_FLAG_STBC;
    		pos++;
    		/* bandwidth */
    		if (status->vht_flag & RX_VHT_FLAG_80MHZ)
    			*pos++ = 4;
    		else if (status->vht_flag & RX_VHT_FLAG_80P80MHZ)
    			*pos++ = 0; /* marked not known above */
    		else if (status->vht_flag & RX_VHT_FLAG_160MHZ)
    			*pos++ = 11;
    		else if (status->flag & RX_FLAG_40MHZ)
    			*pos++ = 1;
    		else /* 20 MHz */
    			*pos++ = 0;
    		/* MCS/NSS */
    		*pos = (status->rate_idx << 4) | status->vht_nss;
    		pos += 4;
    		/* coding field */
    		if (status->flag & RX_FLAG_LDPC)
    			*pos |= IEEE80211_RADIOTAP_CODING_LDPC_USER0;
    		pos++;
    		/* group ID */
    		pos++;
    		/* partial_aid */
    		pos += 2;
    	}
    
    	for_each_set_bit(chain, &chains, IEEE80211_MAX_CHAINS) {
    		*pos++ = status->chain_signal[chain];
    		*pos++ = chain;
    	}
    }
    
    /*
     * This function copies a received frame to all monitor interfaces and
     * returns a cleaned-up SKB that no longer includes the FCS nor the
     * radiotap header the driver might have added.
     */
    static struct sk_buff *
    ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
    		     struct ieee80211_rate *rate)
    {
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
    	struct ieee80211_sub_if_data *sdata;
    	int needed_headroom;
    	struct sk_buff *skb, *skb2;
    	struct net_device *prev_dev = NULL;
    	int present_fcs_len = 0;
    
    	/*
    	 * First, we may need to make a copy of the skb because
    	 *  (1) we need to modify it for radiotap (if not present), and
    	 *  (2) the other RX handlers will modify the skb we got.
    	 *
    	 * We don't need to, of course, if we aren't going to return
    	 * the SKB because it has a bad FCS/PLCP checksum.
    	 */
    
    	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
    		present_fcs_len = FCS_LEN;
    
    	/* ensure hdr->frame_control is in skb head */
    	if (!pskb_may_pull(origskb, 2)) {
    		dev_kfree_skb(origskb);
    		return NULL;
    	}
    
    	if (!local->monitors) {
    		if (should_drop_frame(origskb, present_fcs_len)) {
    			dev_kfree_skb(origskb);
    			return NULL;
    		}
    
    		return remove_monitor_info(local, origskb);
    	}
    
    	/* room for the radiotap header based on driver features */
    	needed_headroom = ieee80211_rx_radiotap_space(local, status);
    
    	if (should_drop_frame(origskb, present_fcs_len)) {
    		/* only need to expand headroom if necessary */
    		skb = origskb;
    		origskb = NULL;
    
    		/*
    		 * This shouldn't trigger often because most devices have an
    		 * RX header they pull before we get here, and that should
    		 * be big enough for our radiotap information. We should
    		 * probably export the length to drivers so that we can have
    		 * them allocate enough headroom to start with.
    		 */
    		if (skb_headroom(skb) < needed_headroom &&
    		    pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
    			dev_kfree_skb(skb);
    			return NULL;
    		}
    	} else {
    		/*
    		 * Need to make a copy and possibly remove radiotap header
    		 * and FCS from the original.
    		 */
    		skb = skb_copy_expand(origskb, needed_headroom, 0, GFP_ATOMIC);
    
    		origskb = remove_monitor_info(local, origskb);
    
    		if (!skb)
    			return origskb;
    	}
    
    	/* prepend radiotap information */
    	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom,
    					 true);
    
    	skb_reset_mac_header(skb);
    	skb->ip_summed = CHECKSUM_UNNECESSARY;
    	skb->pkt_type = PACKET_OTHERHOST;
    	skb->protocol = htons(ETH_P_802_2);
    
    	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
    		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
    			continue;
    
    		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES)
    			continue;
    
    		if (!ieee80211_sdata_running(sdata))
    			continue;
    
    		if (prev_dev) {
    			skb2 = skb_clone(skb, GFP_ATOMIC);
    			if (skb2) {
    				skb2->dev = prev_dev;
    				netif_receive_skb(skb2);
    			}
    		}
    
    		prev_dev = sdata->dev;
    		sdata->dev->stats.rx_packets++;
    		sdata->dev->stats.rx_bytes += skb->len;
    	}
    
    	if (prev_dev) {
    		skb->dev = prev_dev;
    		netif_receive_skb(skb);
    	} else
    		dev_kfree_skb(skb);
    
    	return origskb;
    }
    
    static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
    	int tid, seqno_idx, security_idx;
    
    	/* does the frame have a qos control field? */
    	if (ieee80211_is_data_qos(hdr->frame_control)) {
    		u8 *qc = ieee80211_get_qos_ctl(hdr);
    		/* frame has qos control */
    		tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
    		if (*qc & IEEE80211_QOS_CTL_A_MSDU_PRESENT)
    			status->rx_flags |= IEEE80211_RX_AMSDU;
    
    		seqno_idx = tid;
    		security_idx = tid;
    	} else {
    		/*
    		 * IEEE 802.11-2007, 7.1.3.4.1 ("Sequence Number field"):
    		 *
    		 *	Sequence numbers for management frames, QoS data
    		 *	frames with a broadcast/multicast address in the
    		 *	Address 1 field, and all non-QoS data frames sent
    		 *	by QoS STAs are assigned using an additional single
    		 *	modulo-4096 counter, [...]
    		 *
    		 * We also use that counter for non-QoS STAs.
    		 */
    		seqno_idx = IEEE80211_NUM_TIDS;
    		security_idx = 0;
    		if (ieee80211_is_mgmt(hdr->frame_control))
    			security_idx = IEEE80211_NUM_TIDS;
    		tid = 0;
    	}
    
    	rx->seqno_idx = seqno_idx;
    	rx->security_idx = security_idx;
    	/* Set skb->priority to 1d tag if highest order bit of TID is not set.
    	 * For now, set skb->priority to 0 for other cases. */
    	rx->skb->priority = (tid > 7) ? 0 : tid;
    }
    
    /**
     * DOC: Packet alignment
     *
     * Drivers always need to pass packets that are aligned to two-byte boundaries
     * to the stack.
     *
     * Additionally, should, if possible, align the payload data in a way that
     * guarantees that the contained IP header is aligned to a four-byte
     * boundary. In the case of regular frames, this simply means aligning the
     * payload to a four-byte boundary (because either the IP header is directly
     * contained, or IV/RFC1042 headers that have a length divisible by four are
     * in front of it).  If the payload data is not properly aligned and the
     * architecture doesn't support efficient unaligned operations, mac80211
     * will align the data.
     *
     * With A-MSDU frames, however, the payload data address must yield two modulo
     * four because there are 14-byte 802.3 headers within the A-MSDU frames that
     * push the IP header further back to a multiple of four again. Thankfully, the
     * specs were sane enough this time around to require padding each A-MSDU
     * subframe to a length that is a multiple of four.
     *
     * Padding like Atheros hardware adds which is between the 802.11 header and
     * the payload is not supported, the driver is required to move the 802.11
     * header to be directly in front of the payload in that case.
     */
    static void ieee80211_verify_alignment(struct ieee80211_rx_data *rx)
    {
    #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
    	WARN_ONCE((unsigned long)rx->skb->data & 1,
    		  "unaligned packet at 0x%p\n", rx->skb->data);
    #endif
    }
    
    
    /* rx handlers */
    
    static int ieee80211_is_unicast_robust_mgmt_frame(struct sk_buff *skb)
    {
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
    
    	if (is_multicast_ether_addr(hdr->addr1))
    		return 0;
    
    	return ieee80211_is_robust_mgmt_frame(skb);
    }
    
    
    static int ieee80211_is_multicast_robust_mgmt_frame(struct sk_buff *skb)
    {
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
    
    	if (!is_multicast_ether_addr(hdr->addr1))
    		return 0;
    
    	return ieee80211_is_robust_mgmt_frame(skb);
    }
    
    
    /* Get the BIP key index from MMIE; return -1 if this is not a BIP frame */
    static int ieee80211_get_mmie_keyidx(struct sk_buff *skb)
    {
    	struct ieee80211_mgmt *hdr = (struct ieee80211_mgmt *) skb->data;
    	struct ieee80211_mmie *mmie;
    
    	if (skb->len < 24 + sizeof(*mmie) || !is_multicast_ether_addr(hdr->da))
    		return -1;
    
    	if (!ieee80211_is_robust_mgmt_frame(skb))
    		return -1; /* not a robust management frame */
    
    	mmie = (struct ieee80211_mmie *)
    		(skb->data + skb->len - sizeof(*mmie));
    	if (mmie->element_id != WLAN_EID_MMIE ||
    	    mmie->length != sizeof(*mmie) - 2)
    		return -1;
    
    	return le16_to_cpu(mmie->key_id);
    }
    
    static int iwl80211_get_cs_keyid(const struct ieee80211_cipher_scheme *cs,
    				 struct sk_buff *skb)
    {
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
    	__le16 fc;
    	int hdrlen;
    	u8 keyid;
    
    	fc = hdr->frame_control;
    	hdrlen = ieee80211_hdrlen(fc);
    
    	if (skb->len < hdrlen + cs->hdr_len)
    		return -EINVAL;
    
    	skb_copy_bits(skb, hdrlen + cs->key_idx_off, &keyid, 1);
    	keyid &= cs->key_idx_mask;
    	keyid >>= cs->key_idx_shift;
    
    	return keyid;
    }
    
    static ieee80211_rx_result ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
    	char *dev_addr = rx->sdata->vif.addr;
    
    	if (ieee80211_is_data(hdr->frame_control)) {
    		if (is_multicast_ether_addr(hdr->addr1)) {
    			if (ieee80211_has_tods(hdr->frame_control) ||
    			    !ieee80211_has_fromds(hdr->frame_control))
    				return RX_DROP_MONITOR;
    			if (ether_addr_equal(hdr->addr3, dev_addr))
    				return RX_DROP_MONITOR;
    		} else {
    			if (!ieee80211_has_a4(hdr->frame_control))
    				return RX_DROP_MONITOR;
    			if (ether_addr_equal(hdr->addr4, dev_addr))
    				return RX_DROP_MONITOR;
    		}
    	}
    
    	/* If there is not an established peer link and this is not a peer link
    	 * establisment frame, beacon or probe, drop the frame.
    	 */
    
    	if (!rx->sta || sta_plink_state(rx->sta) != NL80211_PLINK_ESTAB) {
    		struct ieee80211_mgmt *mgmt;
    
    		if (!ieee80211_is_mgmt(hdr->frame_control))
    			return RX_DROP_MONITOR;
    
    		if (ieee80211_is_action(hdr->frame_control)) {
    			u8 category;
    
    			/* make sure category field is present */
    			if (rx->skb->len < IEEE80211_MIN_ACTION_SIZE)
    				return RX_DROP_MONITOR;
    
    			mgmt = (struct ieee80211_mgmt *)hdr;
    			category = mgmt->u.action.category;
    			if (category != WLAN_CATEGORY_MESH_ACTION &&
    			    category != WLAN_CATEGORY_SELF_PROTECTED)
    				return RX_DROP_MONITOR;
    			return RX_CONTINUE;
    		}
    
    		if (ieee80211_is_probe_req(hdr->frame_control) ||
    		    ieee80211_is_probe_resp(hdr->frame_control) ||
    		    ieee80211_is_beacon(hdr->frame_control) ||
    		    ieee80211_is_auth(hdr->frame_control))
    			return RX_CONTINUE;
    
    		return RX_DROP_MONITOR;
    	}
    
    	return RX_CONTINUE;
    }
    
    static void ieee80211_release_reorder_frame(struct ieee80211_sub_if_data *sdata,
    					    struct tid_ampdu_rx *tid_agg_rx,
    					    int index,
    					    struct sk_buff_head *frames)
    {
    	struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
    	struct ieee80211_rx_status *status;
    
    	lockdep_assert_held(&tid_agg_rx->reorder_lock);
    
    	if (!skb)
    		goto no_frame;
    
    	/* release the frame from the reorder ring buffer */
    	tid_agg_rx->stored_mpdu_num--;
    	tid_agg_rx->reorder_buf[index] = NULL;
    	status = IEEE80211_SKB_RXCB(skb);
    	status->rx_flags |= IEEE80211_RX_DEFERRED_RELEASE;
    	__skb_queue_tail(frames, skb);
    
    no_frame:
    	tid_agg_rx->head_seq_num = ieee80211_sn_inc(tid_agg_rx->head_seq_num);
    }
    
    static void ieee80211_release_reorder_frames(struct ieee80211_sub_if_data *sdata,
    					     struct tid_ampdu_rx *tid_agg_rx,
    					     u16 head_seq_num,
    					     struct sk_buff_head *frames)
    {
    	int index;
    
    	lockdep_assert_held(&tid_agg_rx->reorder_lock);
    
    	while (ieee80211_sn_less(tid_agg_rx->head_seq_num, head_seq_num)) {
    		index = tid_agg_rx->head_seq_num % tid_agg_rx->buf_size;
    		ieee80211_release_reorder_frame(sdata, tid_agg_rx, index,
    						frames);
    	}
    }
    
    /*
     * Timeout (in jiffies) for skb's that are waiting in the RX reorder buffer. If
     * the skb was added to the buffer longer than this time ago, the earlier
     * frames that have not yet been received are assumed to be lost and the skb
     * can be released for processing. This may also release other skb's from the
     * reorder buffer if there are no additional gaps between the frames.
     *
     * Callers must hold tid_agg_rx->reorder_lock.
     */
    #define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)
    
    static void ieee80211_sta_reorder_release(struct ieee80211_sub_if_data *sdata,
    					  struct tid_ampdu_rx *tid_agg_rx,
    					  struct sk_buff_head *frames)
    {
    	int index, j;
    
    	lockdep_assert_held(&tid_agg_rx->reorder_lock);
    
    	/* release the buffer until next missing frame */
    	index = tid_agg_rx->head_seq_num % tid_agg_rx->buf_size;
    	if (!tid_agg_rx->reorder_buf[index] &&
    	    tid_agg_rx->stored_mpdu_num) {
    		/*
    		 * No buffers ready to be released, but check whether any
    		 * frames in the reorder buffer have timed out.
    		 */
    		int skipped = 1;
    		for (j = (index + 1) % tid_agg_rx->buf_size; j != index;
    		     j = (j + 1) % tid_agg_rx->buf_size) {
    			if (!tid_agg_rx->reorder_buf[j]) {
    				skipped++;
    				continue;
    			}
    			if (skipped &&
    			    !time_after(jiffies, tid_agg_rx->reorder_time[j] +
    					HT_RX_REORDER_BUF_TIMEOUT))
    				goto set_release_timer;
    
    			ht_dbg_ratelimited(sdata,
    					   "release an RX reorder frame due to timeout on earlier frames\n");
    			ieee80211_release_reorder_frame(sdata, tid_agg_rx, j,
    							frames);
    
    			/*
    			 * Increment the head seq# also for the skipped slots.
    			 */
    			tid_agg_rx->head_seq_num =
    				(tid_agg_rx->head_seq_num +
    				 skipped) & IEEE80211_SN_MASK;
    			skipped = 0;
    		}
    	} else while (tid_agg_rx->reorder_buf[index]) {
    		ieee80211_release_reorder_frame(sdata, tid_agg_rx, index,
    						frames);
    		index =	tid_agg_rx->head_seq_num % tid_agg_rx->buf_size;
    	}
    
    	if (tid_agg_rx->stored_mpdu_num) {
    		j = index = tid_agg_rx->head_seq_num % tid_agg_rx->buf_size;
    
    		for (; j != (index - 1) % tid_agg_rx->buf_size;
    		     j = (j + 1) % tid_agg_rx->buf_size) {
    			if (tid_agg_rx->reorder_buf[j])
    				break;
    		}
    
     set_release_timer:
    
    		mod_timer(&tid_agg_rx->reorder_timer,
    			  tid_agg_rx->reorder_time[j] + 1 +
    			  HT_RX_REORDER_BUF_TIMEOUT);
    	} else {
    		del_timer(&tid_agg_rx->reorder_timer);
    	}
    }
    
    /*
     * As this function belongs to the RX path it must be under
     * rcu_read_lock protection. It returns false if the frame
     * can be processed immediately, true if it was consumed.
     */
    static bool ieee80211_sta_manage_reorder_buf(struct ieee80211_sub_if_data *sdata,
    					     struct tid_ampdu_rx *tid_agg_rx,
    					     struct sk_buff *skb,
    					     struct sk_buff_head *frames)
    {
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
    	u16 sc = le16_to_cpu(hdr->seq_ctrl);
    	u16 mpdu_seq_num = (sc & IEEE80211_SCTL_SEQ) >> 4;
    	u16 head_seq_num, buf_size;
    	int index;
    	bool ret = true;
    
    	spin_lock(&tid_agg_rx->reorder_lock);
    
    	buf_size = tid_agg_rx->buf_size;
    	head_seq_num = tid_agg_rx->head_seq_num;
    
    	/* frame with out of date sequence number */
    	if (ieee80211_sn_less(mpdu_seq_num, head_seq_num)) {
    		dev_kfree_skb(skb);
    		goto out;
    	}
    
    	/*
    	 * If frame the sequence number exceeds our buffering window
    	 * size release some previous frames to make room for this one.
    	 */
    	if (!ieee80211_sn_less(mpdu_seq_num, head_seq_num + buf_size)) {
    		head_seq_num = ieee80211_sn_inc(
    				ieee80211_sn_sub(mpdu_seq_num, buf_size));
    		/* release stored frames up to new head to stack */
    		ieee80211_release_reorder_frames(sdata, tid_agg_rx,
    						 head_seq_num, frames);
    	}
    
    	/* Now the new frame is always in the range of the reordering buffer */
    
    	index = mpdu_seq_num % tid_agg_rx->buf_size;
    
    	/* check if we already stored this frame */
    	if (tid_agg_rx->reorder_buf[index]) {
    		dev_kfree_skb(skb);
    		goto out;
    	}
    
    	/*
    	 * If the current MPDU is in the right order and nothing else
    	 * is stored we can process it directly, no need to buffer it.
    	 * If it is first but there's something stored, we may be able
    	 * to release frames after this one.
    	 */
    	if (mpdu_seq_num == tid_agg_rx->head_seq_num &&
    	    tid_agg_rx->stored_mpdu_num == 0) {
    		tid_agg_rx->head_seq_num =
    			ieee80211_sn_inc(tid_agg_rx->head_seq_num);
    		ret = false;
    		goto out;
    	}
    
    	/* put the frame in the reordering buffer */
    	tid_agg_rx->reorder_buf[index] = skb;
    	tid_agg_rx->reorder_time[index] = jiffies;
    	tid_agg_rx->stored_mpdu_num++;
    	ieee80211_sta_reorder_release(sdata, tid_agg_rx, frames);
    
     out:
    	spin_unlock(&tid_agg_rx->reorder_lock);
    	return ret;
    }
    
    /*
     * Reorder MPDUs from A-MPDUs, keeping them on a buffer. Returns
     * true if the MPDU was buffered, false if it should be processed.
     */
    static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx,
    				       struct sk_buff_head *frames)
    {
    	struct sk_buff *skb = rx->skb;
    	struct ieee80211_local *local = rx->local;
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
    	struct sta_info *sta = rx->sta;
    	struct tid_ampdu_rx *tid_agg_rx;
    	u16 sc;
    	u8 tid, ack_policy;
    
    	if (!ieee80211_is_data_qos(hdr->frame_control) ||
    	    is_multicast_ether_addr(hdr->addr1))
    		goto dont_reorder;
    
    	/*
    	 * filter the QoS data rx stream according to
    	 * STA/TID and check if this STA/TID is on aggregation
    	 */
    
    	if (!sta)
    		goto dont_reorder;
    
    	ack_policy = *ieee80211_get_qos_ctl(hdr) &
    		     IEEE80211_QOS_CTL_ACK_POLICY_MASK;
    	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
    
    	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
    	if (!tid_agg_rx)
    		goto dont_reorder;
    
    	/* qos null data frames are excluded */
    	if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
    		goto dont_reorder;
    
    	/* not part of a BA session */
    	if (ack_policy != IEEE80211_QOS_CTL_ACK_POLICY_BLOCKACK &&
    	    ack_policy != IEEE80211_QOS_CTL_ACK_POLICY_NORMAL)
    		goto dont_reorder;
    
    	/* not actually part of this BA session */
    	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
    		goto dont_reorder;
    
    	/* new, potentially un-ordered, ampdu frame - process it */
    
    	/* reset session timer */
    	if (tid_agg_rx->timeout)
    		tid_agg_rx->last_rx = jiffies;
    
    	/* if this mpdu is fragmented - terminate rx aggregation session */
    	sc = le16_to_cpu(hdr->seq_ctrl);
    	if (sc & IEEE80211_SCTL_FRAG) {
    		skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
    		skb_queue_tail(&rx->sdata->skb_queue, skb);
    		ieee80211_queue_work(&local->hw, &rx->sdata->work);
    		return;
    	}
    
    	/*
    	 * No locking needed -- we will only ever process one
    	 * RX packet at a time, and thus own tid_agg_rx. All
    	 * other code manipulating it needs to (and does) make
    	 * sure that we cannot get to it any more before doing
    	 * anything with it.
    	 */
    	if (ieee80211_sta_manage_reorder_buf(rx->sdata, tid_agg_rx, skb,
    					     frames))
    		return;
    
     dont_reorder:
    	__skb_queue_tail(frames, skb);
    }
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
    
    	/*
    	 * Drop duplicate 802.11 retransmissions
    	 * (IEEE 802.11-2012: 9.3.2.10 "Duplicate detection and recovery")
    	 */
    	if (rx->skb->len >= 24 && rx->sta &&
    	    !ieee80211_is_ctl(hdr->frame_control) &&
    	    !ieee80211_is_qos_nullfunc(hdr->frame_control) &&
    	    !is_multicast_ether_addr(hdr->addr1)) {
    		if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
    			     rx->sta->last_seq_ctrl[rx->seqno_idx] ==
    			     hdr->seq_ctrl)) {
    			if (status->rx_flags & IEEE80211_RX_RA_MATCH) {
    				rx->local->dot11FrameDuplicateCount++;
    				rx->sta->num_duplicates++;
    			}
    			return RX_DROP_UNUSABLE;
    		} else if (!(status->flag & RX_FLAG_AMSDU_MORE)) {
    			rx->sta->last_seq_ctrl[rx->seqno_idx] = hdr->seq_ctrl;
    		}
    	}
    
    	if (unlikely(rx->skb->len < 16)) {
    		I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
    		return RX_DROP_MONITOR;
    	}
    
    	/* Drop disallowed frame classes based on STA auth/assoc state;
    	 * IEEE 802.11, Chap 5.5.
    	 *
    	 * mac80211 filters only based on association state, i.e. it drops
    	 * Class 3 frames from not associated stations. hostapd sends
    	 * deauth/disassoc frames when needed. In addition, hostapd is
    	 * responsible for filtering on both auth and assoc states.
    	 */
    
    	if (ieee80211_vif_is_mesh(&rx->sdata->vif))
    		return ieee80211_rx_mesh_check(rx);
    
    	if (unlikely((ieee80211_is_data(hdr->frame_control) ||
    		      ieee80211_is_pspoll(hdr->frame_control)) &&
    		     rx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
    		     rx->sdata->vif.type != NL80211_IFTYPE_WDS &&
    		     (!rx->sta || !test_sta_flag(rx->sta, WLAN_STA_ASSOC)))) {
    		/*
    		 * accept port control frames from the AP even when it's not
    		 * yet marked ASSOC to prevent a race where we don't set the
    		 * assoc bit quickly enough before it sends the first frame
    		 */
    		if (rx->sta && rx->sdata->vif.type == NL80211_IFTYPE_STATION &&
    		    ieee80211_is_data_present(hdr->frame_control)) {
    			unsigned int hdrlen;
    			__be16 ethertype;
    
    			hdrlen = ieee80211_hdrlen(hdr->frame_control);
    
    			if (rx->skb->len < hdrlen + 8)
    				return RX_DROP_MONITOR;
    
    			skb_copy_bits(rx->skb, hdrlen + 6, &ethertype, 2);
    			if (ethertype == rx->sdata->control_port_protocol)
    				return RX_CONTINUE;
    		}
    
    		if (rx->sdata->vif.type == NL80211_IFTYPE_AP &&
    		    cfg80211_rx_spurious_frame(rx->sdata->dev,
    					       hdr->addr2,
    					       GFP_ATOMIC))
    			return RX_DROP_UNUSABLE;
    
    		return RX_DROP_MONITOR;
    	}
    
    	return RX_CONTINUE;
    }
    
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_check_more_data(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_local *local;
    	struct ieee80211_hdr *hdr;
    	struct sk_buff *skb;
    
    	local = rx->local;
    	skb = rx->skb;
    	hdr = (struct ieee80211_hdr *) skb->data;
    
    	if (!local->pspolling)
    		return RX_CONTINUE;
    
    	if (!ieee80211_has_fromds(hdr->frame_control))
    		/* this is not from AP */
    		return RX_CONTINUE;
    
    	if (!ieee80211_is_data(hdr->frame_control))
    		return RX_CONTINUE;
    
    	if (!ieee80211_has_moredata(hdr->frame_control)) {
    		/* AP has no more frames buffered for us */
    		local->pspolling = false;
    		return RX_CONTINUE;
    	}
    
    	/* more data bit is set, let's request a new frame from the AP */
    	ieee80211_send_pspoll(local, rx->sdata);
    
    	return RX_CONTINUE;
    }
    
    static void sta_ps_start(struct sta_info *sta)
    {
    	struct ieee80211_sub_if_data *sdata = sta->sdata;
    	struct ieee80211_local *local = sdata->local;
    	struct ps_data *ps;
    
    	if (sta->sdata->vif.type == NL80211_IFTYPE_AP ||
    	    sta->sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
    		ps = &sdata->bss->ps;
    	else
    		return;
    
    	atomic_inc(&ps->num_sta_ps);
    	set_sta_flag(sta, WLAN_STA_PS_STA);
    	if (!(local->hw.flags & IEEE80211_HW_AP_LINK_PS))
    		drv_sta_notify(local, sdata, STA_NOTIFY_SLEEP, &sta->sta);
    	ps_dbg(sdata, "STA %pM aid %d enters power save mode\n",
    	       sta->sta.addr, sta->sta.aid);
    }
    
    static void sta_ps_end(struct sta_info *sta)
    {
    	ps_dbg(sta->sdata, "STA %pM aid %d exits power save mode\n",
    	       sta->sta.addr, sta->sta.aid);
    
    	if (test_sta_flag(sta, WLAN_STA_PS_DRIVER)) {
    		ps_dbg(sta->sdata, "STA %pM aid %d driver-ps-blocked\n",
    		       sta->sta.addr, sta->sta.aid);
    		return;
    	}
    
    	ieee80211_sta_ps_deliver_wakeup(sta);
    }
    
    int ieee80211_sta_ps_transition(struct ieee80211_sta *sta, bool start)
    {
    	struct sta_info *sta_inf = container_of(sta, struct sta_info, sta);
    	bool in_ps;
    
    	WARN_ON(!(sta_inf->local->hw.flags & IEEE80211_HW_AP_LINK_PS));
    
    	/* Don't let the same PS state be set twice */
    	in_ps = test_sta_flag(sta_inf, WLAN_STA_PS_STA);
    	if ((start && in_ps) || (!start && !in_ps))
    		return -EINVAL;
    
    	if (start)
    		sta_ps_start(sta_inf);
    	else
    		sta_ps_end(sta_inf);
    
    	return 0;
    }
    EXPORT_SYMBOL(ieee80211_sta_ps_transition);
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_uapsd_and_pspoll(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_sub_if_data *sdata = rx->sdata;
    	struct ieee80211_hdr *hdr = (void *)rx->skb->data;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
    	int tid, ac;
    
    	if (!rx->sta || !(status->rx_flags & IEEE80211_RX_RA_MATCH))
    		return RX_CONTINUE;
    
    	if (sdata->vif.type != NL80211_IFTYPE_AP &&
    	    sdata->vif.type != NL80211_IFTYPE_AP_VLAN)
    		return RX_CONTINUE;
    
    	/*
    	 * The device handles station powersave, so don't do anything about
    	 * uAPSD and PS-Poll frames (the latter shouldn't even come up from
    	 * it to mac80211 since they're handled.)
    	 */
    	if (sdata->local->hw.flags & IEEE80211_HW_AP_LINK_PS)
    		return RX_CONTINUE;
    
    	/*
    	 * Don't do anything if the station isn't already asleep. In
    	 * the uAPSD case, the station will probably be marked asleep,
    	 * in the PS-Poll case the station must be confused ...
    	 */
    	if (!test_sta_flag(rx->sta, WLAN_STA_PS_STA))
    		return RX_CONTINUE;
    
    	if (unlikely(ieee80211_is_pspoll(hdr->frame_control))) {
    		if (!test_sta_flag(rx->sta, WLAN_STA_SP)) {
    			if (!test_sta_flag(rx->sta, WLAN_STA_PS_DRIVER))
    				ieee80211_sta_ps_deliver_poll_response(rx->sta);
    			else
    				set_sta_flag(rx->sta, WLAN_STA_PSPOLL);
    		}
    
    		/* Free PS Poll skb here instead of returning RX_DROP that would
    		 * count as an dropped frame. */
    		dev_kfree_skb(rx->skb);
    
    		return RX_QUEUED;
    	} else if (!ieee80211_has_morefrags(hdr->frame_control) &&
    		   !(status->rx_flags & IEEE80211_RX_DEFERRED_RELEASE) &&
    		   ieee80211_has_pm(hdr->frame_control) &&
    		   (ieee80211_is_data_qos(hdr->frame_control) ||
    		    ieee80211_is_qos_nullfunc(hdr->frame_control))) {
    		tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
    		ac = ieee802_1d_to_ac[tid & 7];
    
    		/*
    		 * If this AC is not trigger-enabled do nothing.
    		 *
    		 * NB: This could/should check a separate bitmap of trigger-
    		 * enabled queues, but for now we only implement uAPSD w/o
    		 * TSPEC changes to the ACs, so they're always the same.
    		 */
    		if (!(rx->sta->sta.uapsd_queues & BIT(ac)))
    			return RX_CONTINUE;
    
    		/* if we are in a service period, do nothing */
    		if (test_sta_flag(rx->sta, WLAN_STA_SP))
    			return RX_CONTINUE;
    
    		if (!test_sta_flag(rx->sta, WLAN_STA_PS_DRIVER))
    			ieee80211_sta_ps_deliver_uapsd(rx->sta);
    		else
    			set_sta_flag(rx->sta, WLAN_STA_UAPSD);
    	}
    
    	return RX_CONTINUE;
    }
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
    {
    	struct sta_info *sta = rx->sta;
    	struct sk_buff *skb = rx->skb;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
    	int i;
    
    	if (!sta)
    		return RX_CONTINUE;
    
    	/*
    	 * Update last_rx only for IBSS packets which are for the current
    	 * BSSID and for station already AUTHORIZED to avoid keeping the
    	 * current IBSS network alive in cases where other STAs start
    	 * using different BSSID. This will also give the station another
    	 * chance to restart the authentication/authorization in case
    	 * something went wrong the first time.
    	 */
    	if (rx->sdata->vif.type == NL80211_IFTYPE_ADHOC) {
    		u8 *bssid = ieee80211_get_bssid(hdr, rx->skb->len,
    						NL80211_IFTYPE_ADHOC);
    		if (ether_addr_equal(bssid, rx->sdata->u.ibss.bssid) &&
    		    test_sta_flag(sta, WLAN_STA_AUTHORIZED)) {
    			sta->last_rx = jiffies;
    			if (ieee80211_is_data(hdr->frame_control)) {
    				sta->last_rx_rate_idx = status->rate_idx;
    				sta->last_rx_rate_flag = status->flag;
    				sta->last_rx_rate_vht_flag = status->vht_flag;
    				sta->last_rx_rate_vht_nss = status->vht_nss;
    			}
    		}
    	} else if (!is_multicast_ether_addr(hdr->addr1)) {
    		/*
    		 * Mesh beacons will update last_rx when if they are found to
    		 * match the current local configuration when processed.
    		 */
    		sta->last_rx = jiffies;
    		if (ieee80211_is_data(hdr->frame_control)) {
    			sta->last_rx_rate_idx = status->rate_idx;
    			sta->last_rx_rate_flag = status->flag;
    			sta->last_rx_rate_vht_flag = status->vht_flag;
    			sta->last_rx_rate_vht_nss = status->vht_nss;
    		}
    	}
    
    	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
    		return RX_CONTINUE;
    
    	if (rx->sdata->vif.type == NL80211_IFTYPE_STATION)
    		ieee80211_sta_rx_notify(rx->sdata, hdr);
    
    	sta->rx_fragments++;
    	sta->rx_bytes += rx->skb->len;
    	if (!(status->flag & RX_FLAG_NO_SIGNAL_VAL)) {
    		sta->last_signal = status->signal;
    		ewma_add(&sta->avg_signal, -status->signal);
    	}
    
    	if (status->chains) {
    		sta->chains = status->chains;
    		for (i = 0; i < ARRAY_SIZE(status->chain_signal); i++) {
    			int signal = status->chain_signal[i];
    
    			if (!(status->chains & BIT(i)))
    				continue;
    
    			sta->chain_signal_last[i] = signal;
    			ewma_add(&sta->chain_signal_avg[i], -signal);
    		}
    	}
    
    	/*
    	 * Change STA power saving mode only at the end of a frame
    	 * exchange sequence.
    	 */
    	if (!(sta->local->hw.flags & IEEE80211_HW_AP_LINK_PS) &&
    	    !ieee80211_has_morefrags(hdr->frame_control) &&
    	    !(status->rx_flags & IEEE80211_RX_DEFERRED_RELEASE) &&
    	    (rx->sdata->vif.type == NL80211_IFTYPE_AP ||
    	     rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN) &&
    	    /* PM bit is only checked in frames where it isn't reserved,
    	     * in AP mode it's reserved in non-bufferable management frames
    	     * (cf. IEEE 802.11-2012 8.2.4.1.7 Power Management field)
    	     */
    	    (!ieee80211_is_mgmt(hdr->frame_control) ||
    	     ieee80211_is_bufferable_mmpdu(hdr->frame_control))) {
    		if (test_sta_flag(sta, WLAN_STA_PS_STA)) {
    			if (!ieee80211_has_pm(hdr->frame_control))
    				sta_ps_end(sta);
    		} else {
    			if (ieee80211_has_pm(hdr->frame_control))
    				sta_ps_start(sta);
    		}
    	}
    
    	/* mesh power save support */
    	if (ieee80211_vif_is_mesh(&rx->sdata->vif))
    		ieee80211_mps_rx_h_sta_process(sta, hdr);
    
    	/*
    	 * Drop (qos-)data::nullfunc frames silently, since they
    	 * are used only to control station power saving mode.
    	 */
    	if (ieee80211_is_nullfunc(hdr->frame_control) ||
    	    ieee80211_is_qos_nullfunc(hdr->frame_control)) {
    		I802_DEBUG_INC(rx->local->rx_handlers_drop_nullfunc);
    
    		/*
    		 * If we receive a 4-addr nullfunc frame from a STA
    		 * that was not moved to a 4-addr STA vlan yet send
    		 * the event to userspace and for older hostapd drop
    		 * the frame to the monitor interface.
    		 */
    		if (ieee80211_has_a4(hdr->frame_control) &&
    		    (rx->sdata->vif.type == NL80211_IFTYPE_AP ||
    		     (rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
    		      !rx->sdata->u.vlan.sta))) {
    			if (!test_and_set_sta_flag(sta, WLAN_STA_4ADDR_EVENT))
    				cfg80211_rx_unexpected_4addr_frame(
    					rx->sdata->dev, sta->sta.addr,
    					GFP_ATOMIC);
    			return RX_DROP_MONITOR;
    		}
    		/*
    		 * Update counter and free packet here to avoid
    		 * counting this as a dropped packed.
    		 */
    		sta->rx_packets++;
    		dev_kfree_skb(rx->skb);
    		return RX_QUEUED;
    	}
    
    	return RX_CONTINUE;
    } /* ieee80211_rx_h_sta_process */
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
    {
    	struct sk_buff *skb = rx->skb;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
    	int keyidx;
    	int hdrlen;
    	ieee80211_rx_result result = RX_DROP_UNUSABLE;
    	struct ieee80211_key *sta_ptk = NULL;
    	int mmie_keyidx = -1;
    	__le16 fc;
    	const struct ieee80211_cipher_scheme *cs = NULL;
    
    	/*
    	 * Key selection 101
    	 *
    	 * There are four types of keys:
    	 *  - GTK (group keys)
    	 *  - IGTK (group keys for management frames)
    	 *  - PTK (pairwise keys)
    	 *  - STK (station-to-station pairwise keys)
    	 *
    	 * When selecting a key, we have to distinguish between multicast
    	 * (including broadcast) and unicast frames, the latter can only
    	 * use PTKs and STKs while the former always use GTKs and IGTKs.
    	 * Unless, of course, actual WEP keys ("pre-RSNA") are used, then
    	 * unicast frames can also use key indices like GTKs. Hence, if we
    	 * don't have a PTK/STK we check the key index for a WEP key.
    	 *
    	 * Note that in a regular BSS, multicast frames are sent by the
    	 * AP only, associated stations unicast the frame to the AP first
    	 * which then multicasts it on their behalf.
    	 *
    	 * There is also a slight problem in IBSS mode: GTKs are negotiated
    	 * with each station, that is something we don't currently handle.
    	 * The spec seems to expect that one negotiates the same key with
    	 * every station but there's no such requirement; VLANs could be
    	 * possible.
    	 */
    
    	/*
    	 * No point in finding a key and decrypting if the frame is neither
    	 * addressed to us nor a multicast frame.
    	 */
    	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
    		return RX_CONTINUE;
    
    	/* start without a key */
    	rx->key = NULL;
    	fc = hdr->frame_control;
    
    	if (rx->sta) {
    		int keyid = rx->sta->ptk_idx;
    
    		if (ieee80211_has_protected(fc) && rx->sta->cipher_scheme) {
    			cs = rx->sta->cipher_scheme;
    			keyid = iwl80211_get_cs_keyid(cs, rx->skb);
    			if (unlikely(keyid < 0))
    				return RX_DROP_UNUSABLE;
    		}
    		sta_ptk = rcu_dereference(rx->sta->ptk[keyid]);
    	}
    
    	if (!ieee80211_has_protected(fc))
    		mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);
    
    	if (!is_multicast_ether_addr(hdr->addr1) && sta_ptk) {
    		rx->key = sta_ptk;
    		if ((status->flag & RX_FLAG_DECRYPTED) &&
    		    (status->flag & RX_FLAG_IV_STRIPPED))
    			return RX_CONTINUE;
    		/* Skip decryption if the frame is not protected. */
    		if (!ieee80211_has_protected(fc))
    			return RX_CONTINUE;
    	} else if (mmie_keyidx >= 0) {
    		/* Broadcast/multicast robust management frame / BIP */
    		if ((status->flag & RX_FLAG_DECRYPTED) &&
    		    (status->flag & RX_FLAG_IV_STRIPPED))
    			return RX_CONTINUE;
    
    		if (mmie_keyidx < NUM_DEFAULT_KEYS ||
    		    mmie_keyidx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
    			return RX_DROP_MONITOR; /* unexpected BIP keyidx */
    		if (rx->sta)
    			rx->key = rcu_dereference(rx->sta->gtk[mmie_keyidx]);
    		if (!rx->key)
    			rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
    	} else if (!ieee80211_has_protected(fc)) {
    		/*
    		 * The frame was not protected, so skip decryption. However, we
    		 * need to set rx->key if there is a key that could have been
    		 * used so that the frame may be dropped if encryption would
    		 * have been expected.
    		 */
    		struct ieee80211_key *key = NULL;
    		struct ieee80211_sub_if_data *sdata = rx->sdata;
    		int i;
    
    		if (ieee80211_is_mgmt(fc) &&
    		    is_multicast_ether_addr(hdr->addr1) &&
    		    (key = rcu_dereference(rx->sdata->default_mgmt_key)))
    			rx->key = key;
    		else {
    			if (rx->sta) {
    				for (i = 0; i < NUM_DEFAULT_KEYS; i++) {
    					key = rcu_dereference(rx->sta->gtk[i]);
    					if (key)
    						break;
    				}
    			}
    			if (!key) {
    				for (i = 0; i < NUM_DEFAULT_KEYS; i++) {
    					key = rcu_dereference(sdata->keys[i]);
    					if (key)
    						break;
    				}
    			}
    			if (key)
    				rx->key = key;
    		}
    		return RX_CONTINUE;
    	} else {
    		u8 keyid;
    
    		/*
    		 * The device doesn't give us the IV so we won't be
    		 * able to look up the key. That's ok though, we
    		 * don't need to decrypt the frame, we just won't
    		 * be able to keep statistics accurate.
    		 * Except for key threshold notifications, should
    		 * we somehow allow the driver to tell us which key
    		 * the hardware used if this flag is set?
    		 */
    		if ((status->flag & RX_FLAG_DECRYPTED) &&
    		    (status->flag & RX_FLAG_IV_STRIPPED))
    			return RX_CONTINUE;
    
    		hdrlen = ieee80211_hdrlen(fc);
    
    		if (cs) {
    			keyidx = iwl80211_get_cs_keyid(cs, rx->skb);
    
    			if (unlikely(keyidx < 0))
    				return RX_DROP_UNUSABLE;
    		} else {
    			if (rx->skb->len < 8 + hdrlen)
    				return RX_DROP_UNUSABLE; /* TODO: count this? */
    			/*
    			 * no need to call ieee80211_wep_get_keyidx,
    			 * it verifies a bunch of things we've done already
    			 */
    			skb_copy_bits(rx->skb, hdrlen + 3, &keyid, 1);
    			keyidx = keyid >> 6;
    		}
    
    		/* check per-station GTK first, if multicast packet */
    		if (is_multicast_ether_addr(hdr->addr1) && rx->sta)
    			rx->key = rcu_dereference(rx->sta->gtk[keyidx]);
    
    		/* if not found, try default key */
    		if (!rx->key) {
    			rx->key = rcu_dereference(rx->sdata->keys[keyidx]);
    
    			/*
    			 * RSNA-protected unicast frames should always be
    			 * sent with pairwise or station-to-station keys,
    			 * but for WEP we allow using a key index as well.
    			 */
    			if (rx->key &&
    			    rx->key->conf.cipher != WLAN_CIPHER_SUITE_WEP40 &&
    			    rx->key->conf.cipher != WLAN_CIPHER_SUITE_WEP104 &&
    			    !is_multicast_ether_addr(hdr->addr1))
    				rx->key = NULL;
    		}
    	}
    
    	if (rx->key) {
    		if (unlikely(rx->key->flags & KEY_FLAG_TAINTED))
    			return RX_DROP_MONITOR;
    
    		rx->key->tx_rx_count++;
    		/* TODO: add threshold stuff again */
    	} else {
    		return RX_DROP_MONITOR;
    	}
    
    	switch (rx->key->conf.cipher) {
    	case WLAN_CIPHER_SUITE_WEP40:
    	case WLAN_CIPHER_SUITE_WEP104:
    		result = ieee80211_crypto_wep_decrypt(rx);
    		break;
    	case WLAN_CIPHER_SUITE_TKIP:
    		result = ieee80211_crypto_tkip_decrypt(rx);
    		break;
    	case WLAN_CIPHER_SUITE_CCMP:
    		result = ieee80211_crypto_ccmp_decrypt(rx);
    		break;
    	case WLAN_CIPHER_SUITE_AES_CMAC:
    		result = ieee80211_crypto_aes_cmac_decrypt(rx);
    		break;
    	default:
    		result = ieee80211_crypto_hw_decrypt(rx);
    	}
    
    	/* the hdr variable is invalid after the decrypt handlers */
    
    	/* either the frame has been decrypted or will be dropped */
    	status->flag |= RX_FLAG_DECRYPTED;
    
    	return result;
    }
    
    static inline struct ieee80211_fragment_entry *
    ieee80211_reassemble_add(struct ieee80211_sub_if_data *sdata,
    			 unsigned int frag, unsigned int seq, int rx_queue,
    			 struct sk_buff **skb)
    {
    	struct ieee80211_fragment_entry *entry;
    
    	entry = &sdata->fragments[sdata->fragment_next++];
    	if (sdata->fragment_next >= IEEE80211_FRAGMENT_MAX)
    		sdata->fragment_next = 0;
    
    	if (!skb_queue_empty(&entry->skb_list))
    		__skb_queue_purge(&entry->skb_list);
    
    	__skb_queue_tail(&entry->skb_list, *skb); /* no need for locking */
    	*skb = NULL;
    	entry->first_frag_time = jiffies;
    	entry->seq = seq;
    	entry->rx_queue = rx_queue;
    	entry->last_frag = frag;
    	entry->ccmp = 0;
    	entry->extra_len = 0;
    
    	return entry;
    }
    
    static inline struct ieee80211_fragment_entry *
    ieee80211_reassemble_find(struct ieee80211_sub_if_data *sdata,
    			  unsigned int frag, unsigned int seq,
    			  int rx_queue, struct ieee80211_hdr *hdr)
    {
    	struct ieee80211_fragment_entry *entry;
    	int i, idx;
    
    	idx = sdata->fragment_next;
    	for (i = 0; i < IEEE80211_FRAGMENT_MAX; i++) {
    		struct ieee80211_hdr *f_hdr;
    
    		idx--;
    		if (idx < 0)
    			idx = IEEE80211_FRAGMENT_MAX - 1;
    
    		entry = &sdata->fragments[idx];
    		if (skb_queue_empty(&entry->skb_list) || entry->seq != seq ||
    		    entry->rx_queue != rx_queue ||
    		    entry->last_frag + 1 != frag)
    			continue;
    
    		f_hdr = (struct ieee80211_hdr *)entry->skb_list.next->data;
    
    		/*
    		 * Check ftype and addresses are equal, else check next fragment
    		 */
    		if (((hdr->frame_control ^ f_hdr->frame_control) &
    		     cpu_to_le16(IEEE80211_FCTL_FTYPE)) ||
    		    !ether_addr_equal(hdr->addr1, f_hdr->addr1) ||
    		    !ether_addr_equal(hdr->addr2, f_hdr->addr2))
    			continue;
    
    		if (time_after(jiffies, entry->first_frag_time + 2 * HZ)) {
    			__skb_queue_purge(&entry->skb_list);
    			continue;
    		}
    		return entry;
    	}
    
    	return NULL;
    }
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_hdr *hdr;
    	u16 sc;
    	__le16 fc;
    	unsigned int frag, seq;
    	struct ieee80211_fragment_entry *entry;
    	struct sk_buff *skb;
    	struct ieee80211_rx_status *status;
    
    	hdr = (struct ieee80211_hdr *)rx->skb->data;
    	fc = hdr->frame_control;
    
    	if (ieee80211_is_ctl(fc))
    		return RX_CONTINUE;
    
    	sc = le16_to_cpu(hdr->seq_ctrl);
    	frag = sc & IEEE80211_SCTL_FRAG;
    
    	if (likely((!ieee80211_has_morefrags(fc) && frag == 0) ||
    		   is_multicast_ether_addr(hdr->addr1))) {
    		/* not fragmented */
    		goto out;
    	}
    	I802_DEBUG_INC(rx->local->rx_handlers_fragments);
    
    	if (skb_linearize(rx->skb))
    		return RX_DROP_UNUSABLE;
    
    	/*
    	 *  skb_linearize() might change the skb->data and
    	 *  previously cached variables (in this case, hdr) need to
    	 *  be refreshed with the new data.
    	 */
    	hdr = (struct ieee80211_hdr *)rx->skb->data;
    	seq = (sc & IEEE80211_SCTL_SEQ) >> 4;
    
    	if (frag == 0) {
    		/* This is the first fragment of a new frame. */
    		entry = ieee80211_reassemble_add(rx->sdata, frag, seq,
    						 rx->seqno_idx, &(rx->skb));
    		if (rx->key && rx->key->conf.cipher == WLAN_CIPHER_SUITE_CCMP &&
    		    ieee80211_has_protected(fc)) {
    			int queue = rx->security_idx;
    			/* Store CCMP PN so that we can verify that the next
    			 * fragment has a sequential PN value. */
    			entry->ccmp = 1;
    			memcpy(entry->last_pn,
    			       rx->key->u.ccmp.rx_pn[queue],
    			       IEEE80211_CCMP_PN_LEN);
    		}
    		return RX_QUEUED;
    	}
    
    	/* This is a fragment for a frame that should already be pending in
    	 * fragment cache. Add this fragment to the end of the pending entry.
    	 */
    	entry = ieee80211_reassemble_find(rx->sdata, frag, seq,
    					  rx->seqno_idx, hdr);
    	if (!entry) {
    		I802_DEBUG_INC(rx->local->rx_handlers_drop_defrag);
    		return RX_DROP_MONITOR;
    	}
    
    	/* Verify that MPDUs within one MSDU have sequential PN values.
    	 * (IEEE 802.11i, 8.3.3.4.5) */
    	if (entry->ccmp) {
    		int i;
    		u8 pn[IEEE80211_CCMP_PN_LEN], *rpn;
    		int queue;
    		if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_CCMP)
    			return RX_DROP_UNUSABLE;
    		memcpy(pn, entry->last_pn, IEEE80211_CCMP_PN_LEN);
    		for (i = IEEE80211_CCMP_PN_LEN - 1; i >= 0; i--) {
    			pn[i]++;
    			if (pn[i])
    				break;
    		}
    		queue = rx->security_idx;
    		rpn = rx->key->u.ccmp.rx_pn[queue];
    		if (memcmp(pn, rpn, IEEE80211_CCMP_PN_LEN))
    			return RX_DROP_UNUSABLE;
    		memcpy(entry->last_pn, pn, IEEE80211_CCMP_PN_LEN);
    	}
    
    	skb_pull(rx->skb, ieee80211_hdrlen(fc));
    	__skb_queue_tail(&entry->skb_list, rx->skb);
    	entry->last_frag = frag;
    	entry->extra_len += rx->skb->len;
    	if (ieee80211_has_morefrags(fc)) {
    		rx->skb = NULL;
    		return RX_QUEUED;
    	}
    
    	rx->skb = __skb_dequeue(&entry->skb_list);
    	if (skb_tailroom(rx->skb) < entry->extra_len) {
    		I802_DEBUG_INC(rx->local->rx_expand_skb_head2);
    		if (unlikely(pskb_expand_head(rx->skb, 0, entry->extra_len,
    					      GFP_ATOMIC))) {
    			I802_DEBUG_INC(rx->local->rx_handlers_drop_defrag);
    			__skb_queue_purge(&entry->skb_list);
    			return RX_DROP_UNUSABLE;
    		}
    	}
    	while ((skb = __skb_dequeue(&entry->skb_list))) {
    		memcpy(skb_put(rx->skb, skb->len), skb->data, skb->len);
    		dev_kfree_skb(skb);
    	}
    
    	/* Complete frame has been reassembled - process it now */
    	status = IEEE80211_SKB_RXCB(rx->skb);
    	status->rx_flags |= IEEE80211_RX_FRAGMENTED;
    
     out:
    	if (rx->sta)
    		rx->sta->rx_packets++;
    	if (is_multicast_ether_addr(hdr->addr1))
    		rx->local->dot11MulticastReceivedFrameCount++;
    	else
    		ieee80211_led_rx(rx->local);
    	return RX_CONTINUE;
    }
    
    static int ieee80211_802_1x_port_control(struct ieee80211_rx_data *rx)
    {
    	if (unlikely(!rx->sta || !test_sta_flag(rx->sta, WLAN_STA_AUTHORIZED)))
    		return -EACCES;
    
    	return 0;
    }
    
    static int ieee80211_drop_unencrypted(struct ieee80211_rx_data *rx, __le16 fc)
    {
    	struct sk_buff *skb = rx->skb;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
    
    	/*
    	 * Pass through unencrypted frames if the hardware has
    	 * decrypted them already.
    	 */
    	if (status->flag & RX_FLAG_DECRYPTED)
    		return 0;
    
    	/* Drop unencrypted frames if key is set. */
    	if (unlikely(!ieee80211_has_protected(fc) &&
    		     !ieee80211_is_nullfunc(fc) &&
    		     ieee80211_is_data(fc) &&
    		     (rx->key || rx->sdata->drop_unencrypted)))
    		return -EACCES;
    
    	return 0;
    }
    
    static int ieee80211_drop_unencrypted_mgmt(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
    	__le16 fc = hdr->frame_control;
    
    	/*
    	 * Pass through unencrypted frames if the hardware has
    	 * decrypted them already.
    	 */
    	if (status->flag & RX_FLAG_DECRYPTED)
    		return 0;
    
    	if (rx->sta && test_sta_flag(rx->sta, WLAN_STA_MFP)) {
    		if (unlikely(!ieee80211_has_protected(fc) &&
    			     ieee80211_is_unicast_robust_mgmt_frame(rx->skb) &&
    			     rx->key)) {
    			if (ieee80211_is_deauth(fc) ||
    			    ieee80211_is_disassoc(fc))
    				cfg80211_rx_unprot_mlme_mgmt(rx->sdata->dev,
    							     rx->skb->data,
    							     rx->skb->len);
    			return -EACCES;
    		}
    		/* BIP does not use Protected field, so need to check MMIE */
    		if (unlikely(ieee80211_is_multicast_robust_mgmt_frame(rx->skb) &&
    			     ieee80211_get_mmie_keyidx(rx->skb) < 0)) {
    			if (ieee80211_is_deauth(fc) ||
    			    ieee80211_is_disassoc(fc))
    				cfg80211_rx_unprot_mlme_mgmt(rx->sdata->dev,
    							     rx->skb->data,
    							     rx->skb->len);
    			return -EACCES;
    		}
    		/*
    		 * When using MFP, Action frames are not allowed prior to
    		 * having configured keys.
    		 */
    		if (unlikely(ieee80211_is_action(fc) && !rx->key &&
    			     ieee80211_is_robust_mgmt_frame(rx->skb)))
    			return -EACCES;
    	}
    
    	return 0;
    }
    
    static int
    __ieee80211_data_to_8023(struct ieee80211_rx_data *rx, bool *port_control)
    {
    	struct ieee80211_sub_if_data *sdata = rx->sdata;
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
    	bool check_port_control = false;
    	struct ethhdr *ehdr;
    	int ret;
    
    	*port_control = false;
    	if (ieee80211_has_a4(hdr->frame_control) &&
    	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN && !sdata->u.vlan.sta)
    		return -1;
    
    	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
    	    !!sdata->u.mgd.use_4addr != !!ieee80211_has_a4(hdr->frame_control)) {
    
    		if (!sdata->u.mgd.use_4addr)
    			return -1;
    		else
    			check_port_control = true;
    	}
    
    	if (is_multicast_ether_addr(hdr->addr1) &&
    	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN && sdata->u.vlan.sta)
    		return -1;
    
    	ret = ieee80211_data_to_8023(rx->skb, sdata->vif.addr, sdata->vif.type);
    	if (ret < 0)
    		return ret;
    
    	ehdr = (struct ethhdr *) rx->skb->data;
    	if (ehdr->h_proto == rx->sdata->control_port_protocol)
    		*port_control = true;
    	else if (check_port_control)
    		return -1;
    
    	return 0;
    }
    
    /*
     * requires that rx->skb is a frame with ethernet header
     */
    static bool ieee80211_frame_allowed(struct ieee80211_rx_data *rx, __le16 fc)
    {
    	static const u8 pae_group_addr[ETH_ALEN] __aligned(2)
    		= { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x03 };
    	struct ethhdr *ehdr = (struct ethhdr *) rx->skb->data;
    
    	/*
    	 * Allow EAPOL frames to us/the PAE group address regardless
    	 * of whether the frame was encrypted or not.
    	 */
    	if (ehdr->h_proto == rx->sdata->control_port_protocol &&
    	    (ether_addr_equal(ehdr->h_dest, rx->sdata->vif.addr) ||
    	     ether_addr_equal(ehdr->h_dest, pae_group_addr)))
    		return true;
    
    	if (ieee80211_802_1x_port_control(rx) ||
    	    ieee80211_drop_unencrypted(rx, fc))
    		return false;
    
    	return true;
    }
    
    /*
     * requires that rx->skb is a frame with ethernet header
     */
    static void
    ieee80211_deliver_skb(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_sub_if_data *sdata = rx->sdata;
    	struct net_device *dev = sdata->dev;
    	struct sk_buff *skb, *xmit_skb;
    	struct ethhdr *ehdr = (struct ethhdr *) rx->skb->data;
    	struct sta_info *dsta;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
    
    	skb = rx->skb;
    	xmit_skb = NULL;
    
    	if ((sdata->vif.type == NL80211_IFTYPE_AP ||
    	     sdata->vif.type == NL80211_IFTYPE_AP_VLAN) &&
    	    !(sdata->flags & IEEE80211_SDATA_DONT_BRIDGE_PACKETS) &&
    	    (status->rx_flags & IEEE80211_RX_RA_MATCH) &&
    	    (sdata->vif.type != NL80211_IFTYPE_AP_VLAN || !sdata->u.vlan.sta)) {
    		if (is_multicast_ether_addr(ehdr->h_dest)) {
    			/*
    			 * send multicast frames both to higher layers in
    			 * local net stack and back to the wireless medium
    			 */
    			xmit_skb = skb_copy(skb, GFP_ATOMIC);
    			if (!xmit_skb)
    				net_info_ratelimited("%s: failed to clone multicast frame\n",
    						    dev->name);
    		} else {
    			dsta = sta_info_get(sdata, skb->data);
    			if (dsta) {
    				/*
    				 * The destination station is associated to
    				 * this AP (in this VLAN), so send the frame
    				 * directly to it and do not pass it to local
    				 * net stack.
    				 */
    				xmit_skb = skb;
    				skb = NULL;
    			}
    		}
    	}
    
    #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
    	if (skb) {
    		/* 'align' will only take the values 0 or 2 here since all
    		 * frames are required to be aligned to 2-byte boundaries
    		 * when being passed to mac80211; the code here works just
    		 * as well if that isn't true, but mac80211 assumes it can
    		 * access fields as 2-byte aligned (e.g. for ether_addr_equal)
    		 */
    		int align;
    
    		align = (unsigned long)(skb->data + sizeof(struct ethhdr)) & 3;
    		if (align) {
    			if (WARN_ON(skb_headroom(skb) < 3)) {
    				dev_kfree_skb(skb);
    				skb = NULL;
    			} else {
    				u8 *data = skb->data;
    				size_t len = skb_headlen(skb);
    				skb->data -= align;
    				memmove(skb->data, data, len);
    				skb_set_tail_pointer(skb, len);
    			}
    		}
    	}
    #endif
    
    	if (skb) {
    		/* deliver to local stack */
    		skb->protocol = eth_type_trans(skb, dev);
    		memset(skb->cb, 0, sizeof(skb->cb));
    		if (rx->local->napi)
    			napi_gro_receive(rx->local->napi, skb);
    		else
    			netif_receive_skb(skb);
    	}
    
    	if (xmit_skb) {
    		/*
    		 * Send to wireless media and increase priority by 256 to
    		 * keep the received priority instead of reclassifying
    		 * the frame (see cfg80211_classify8021d).
    		 */
    		xmit_skb->priority += 256;
    		xmit_skb->protocol = htons(ETH_P_802_3);
    		skb_reset_network_header(xmit_skb);
    		skb_reset_mac_header(xmit_skb);
    		dev_queue_xmit(xmit_skb);
    	}
    }
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
    {
    	struct net_device *dev = rx->sdata->dev;
    	struct sk_buff *skb = rx->skb;
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
    	__le16 fc = hdr->frame_control;
    	struct sk_buff_head frame_list;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
    
    	if (unlikely(!ieee80211_is_data(fc)))
    		return RX_CONTINUE;
    
    	if (unlikely(!ieee80211_is_data_present(fc)))
    		return RX_DROP_MONITOR;
    
    	if (!(status->rx_flags & IEEE80211_RX_AMSDU))
    		return RX_CONTINUE;
    
    	if (ieee80211_has_a4(hdr->frame_control) &&
    	    rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
    	    !rx->sdata->u.vlan.sta)
    		return RX_DROP_UNUSABLE;
    
    	if (is_multicast_ether_addr(hdr->addr1) &&
    	    ((rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
    	      rx->sdata->u.vlan.sta) ||
    	     (rx->sdata->vif.type == NL80211_IFTYPE_STATION &&
    	      rx->sdata->u.mgd.use_4addr)))
    		return RX_DROP_UNUSABLE;
    
    	skb->dev = dev;
    	__skb_queue_head_init(&frame_list);
    
    	if (skb_linearize(skb))
    		return RX_DROP_UNUSABLE;
    
    	ieee80211_amsdu_to_8023s(skb, &frame_list, dev->dev_addr,
    				 rx->sdata->vif.type,
    				 rx->local->hw.extra_tx_headroom, true);
    
    	while (!skb_queue_empty(&frame_list)) {
    		rx->skb = __skb_dequeue(&frame_list);
    
    		if (!ieee80211_frame_allowed(rx, fc)) {
    			dev_kfree_skb(rx->skb);
    			continue;
    		}
    		dev->stats.rx_packets++;
    		dev->stats.rx_bytes += rx->skb->len;
    
    		ieee80211_deliver_skb(rx);
    	}
    
    	return RX_QUEUED;
    }
    
    #ifdef CONFIG_MAC80211_MESH
    static ieee80211_rx_result
    ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_hdr *fwd_hdr, *hdr;
    	struct ieee80211_tx_info *info;
    	struct ieee80211s_hdr *mesh_hdr;
    	struct sk_buff *skb = rx->skb, *fwd_skb;
    	struct ieee80211_local *local = rx->local;
    	struct ieee80211_sub_if_data *sdata = rx->sdata;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
    	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
    	u16 q, hdrlen;
    
    	hdr = (struct ieee80211_hdr *) skb->data;
    	hdrlen = ieee80211_hdrlen(hdr->frame_control);
    
    	/* make sure fixed part of mesh header is there, also checks skb len */
    	if (!pskb_may_pull(rx->skb, hdrlen + 6))
    		return RX_DROP_MONITOR;
    
    	mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
    
    	/* make sure full mesh header is there, also checks skb len */
    	if (!pskb_may_pull(rx->skb,
    			   hdrlen + ieee80211_get_mesh_hdrlen(mesh_hdr)))
    		return RX_DROP_MONITOR;
    
    	/* reload pointers */
    	hdr = (struct ieee80211_hdr *) skb->data;
    	mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
    
    	/* frame is in RMC, don't forward */
    	if (ieee80211_is_data(hdr->frame_control) &&
    	    is_multicast_ether_addr(hdr->addr1) &&
    	    mesh_rmc_check(rx->sdata, hdr->addr3, mesh_hdr))
    		return RX_DROP_MONITOR;
    
    	if (!ieee80211_is_data(hdr->frame_control) ||
    	    !(status->rx_flags & IEEE80211_RX_RA_MATCH))
    		return RX_CONTINUE;
    
    	if (!mesh_hdr->ttl)
    		return RX_DROP_MONITOR;
    
    	if (mesh_hdr->flags & MESH_FLAGS_AE) {
    		struct mesh_path *mppath;
    		char *proxied_addr;
    		char *mpp_addr;
    
    		if (is_multicast_ether_addr(hdr->addr1)) {
    			mpp_addr = hdr->addr3;
    			proxied_addr = mesh_hdr->eaddr1;
    		} else if (mesh_hdr->flags & MESH_FLAGS_AE_A5_A6) {
    			/* has_a4 already checked in ieee80211_rx_mesh_check */
    			mpp_addr = hdr->addr4;
    			proxied_addr = mesh_hdr->eaddr2;
    		} else {
    			return RX_DROP_MONITOR;
    		}
    
    		rcu_read_lock();
    		mppath = mpp_path_lookup(sdata, proxied_addr);
    		if (!mppath) {
    			mpp_path_add(sdata, proxied_addr, mpp_addr);
    		} else {
    			spin_lock_bh(&mppath->state_lock);
    			if (!ether_addr_equal(mppath->mpp, mpp_addr))
    				memcpy(mppath->mpp, mpp_addr, ETH_ALEN);
    			spin_unlock_bh(&mppath->state_lock);
    		}
    		rcu_read_unlock();
    	}
    
    	/* Frame has reached destination.  Don't forward */
    	if (!is_multicast_ether_addr(hdr->addr1) &&
    	    ether_addr_equal(sdata->vif.addr, hdr->addr3))
    		return RX_CONTINUE;
    
    	q = ieee80211_select_queue_80211(sdata, skb, hdr);
    	if (ieee80211_queue_stopped(&local->hw, q)) {
    		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, dropped_frames_congestion);
    		return RX_DROP_MONITOR;
    	}
    	skb_set_queue_mapping(skb, q);
    
    	if (!--mesh_hdr->ttl) {
    		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, dropped_frames_ttl);
    		goto out;
    	}
    
    	if (!ifmsh->mshcfg.dot11MeshForwarding)
    		goto out;
    
    	fwd_skb = skb_copy(skb, GFP_ATOMIC);
    	if (!fwd_skb) {
    		net_info_ratelimited("%s: failed to clone mesh frame\n",
    				    sdata->name);
    		goto out;
    	}
    
    	fwd_hdr =  (struct ieee80211_hdr *) fwd_skb->data;
    	fwd_hdr->frame_control &= ~cpu_to_le16(IEEE80211_FCTL_RETRY);
    	info = IEEE80211_SKB_CB(fwd_skb);
    	memset(info, 0, sizeof(*info));
    	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
    	info->control.vif = &rx->sdata->vif;
    	info->control.jiffies = jiffies;
    	if (is_multicast_ether_addr(fwd_hdr->addr1)) {
    		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, fwded_mcast);
    		memcpy(fwd_hdr->addr2, sdata->vif.addr, ETH_ALEN);
    		/* update power mode indication when forwarding */
    		ieee80211_mps_set_frame_flags(sdata, NULL, fwd_hdr);
    	} else if (!mesh_nexthop_lookup(sdata, fwd_skb)) {
    		/* mesh power mode flags updated in mesh_nexthop_lookup */
    		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, fwded_unicast);
    	} else {
    		/* unable to resolve next hop */
    		mesh_path_error_tx(sdata, ifmsh->mshcfg.element_ttl,
    				   fwd_hdr->addr3, 0,
    				   WLAN_REASON_MESH_PATH_NOFORWARD,
    				   fwd_hdr->addr2);
    		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, dropped_frames_no_route);
    		kfree_skb(fwd_skb);
    		return RX_DROP_MONITOR;
    	}
    
    	IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, fwded_frames);
    	ieee80211_add_pending_skb(local, fwd_skb);
     out:
    	if (is_multicast_ether_addr(hdr->addr1) ||
    	    sdata->dev->flags & IFF_PROMISC)
    		return RX_CONTINUE;
    	else
    		return RX_DROP_MONITOR;
    }
    #endif
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_data(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_sub_if_data *sdata = rx->sdata;
    	struct ieee80211_local *local = rx->local;
    	struct net_device *dev = sdata->dev;
    	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
    	__le16 fc = hdr->frame_control;
    	bool port_control;
    	int err;
    
    	if (unlikely(!ieee80211_is_data(hdr->frame_control)))
    		return RX_CONTINUE;
    
    	if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
    		return RX_DROP_MONITOR;
    
    	/*
    	 * Send unexpected-4addr-frame event to hostapd. For older versions,
    	 * also drop the frame to cooked monitor interfaces.
    	 */
    	if (ieee80211_has_a4(hdr->frame_control) &&
    	    sdata->vif.type == NL80211_IFTYPE_AP) {
    		if (rx->sta &&
    		    !test_and_set_sta_flag(rx->sta, WLAN_STA_4ADDR_EVENT))
    			cfg80211_rx_unexpected_4addr_frame(
    				rx->sdata->dev, rx->sta->sta.addr, GFP_ATOMIC);
    		return RX_DROP_MONITOR;
    	}
    
    	err = __ieee80211_data_to_8023(rx, &port_control);
    	if (unlikely(err))
    		return RX_DROP_UNUSABLE;
    
    	if (!ieee80211_frame_allowed(rx, fc))
    		return RX_DROP_MONITOR;
    
    	if (rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
    	    unlikely(port_control) && sdata->bss) {
    		sdata = container_of(sdata->bss, struct ieee80211_sub_if_data,
    				     u.ap);
    		dev = sdata->dev;
    		rx->sdata = sdata;
    	}
    
    	rx->skb->dev = dev;
    
    	dev->stats.rx_packets++;
    	dev->stats.rx_bytes += rx->skb->len;
    
    	if (local->ps_sdata && local->hw.conf.dynamic_ps_timeout > 0 &&
    	    !is_multicast_ether_addr(
    		    ((struct ethhdr *)rx->skb->data)->h_dest) &&
    	    (!local->scanning &&
    	     !test_bit(SDATA_STATE_OFFCHANNEL, &sdata->state))) {
    			mod_timer(&local->dynamic_ps_timer, jiffies +
    			 msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
    	}
    
    	ieee80211_deliver_skb(rx);
    
    	return RX_QUEUED;
    }
    
    static ieee80211_rx_result debug_noinline
    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;
    
    		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;
    
    		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;
    
    		/* 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);
    
    		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;
    }
    
    static void ieee80211_process_sa_query_req(struct ieee80211_sub_if_data *sdata,
    					   struct ieee80211_mgmt *mgmt,
    					   size_t len)
    {
    	struct ieee80211_local *local = sdata->local;
    	struct sk_buff *skb;
    	struct ieee80211_mgmt *resp;
    
    	if (!ether_addr_equal(mgmt->da, sdata->vif.addr)) {
    		/* Not to own unicast address */
    		return;
    	}
    
    	if (!ether_addr_equal(mgmt->sa, sdata->u.mgd.bssid) ||
    	    !ether_addr_equal(mgmt->bssid, sdata->u.mgd.bssid)) {
    		/* Not from the current AP or not associated yet. */
    		return;
    	}
    
    	if (len < 24 + 1 + sizeof(resp->u.action.u.sa_query)) {
    		/* Too short SA Query request frame */
    		return;
    	}
    
    	skb = dev_alloc_skb(sizeof(*resp) + local->hw.extra_tx_headroom);
    	if (skb == NULL)
    		return;
    
    	skb_reserve(skb, local->hw.extra_tx_headroom);
    	resp = (struct ieee80211_mgmt *) skb_put(skb, 24);
    	memset(resp, 0, 24);
    	memcpy(resp->da, mgmt->sa, ETH_ALEN);
    	memcpy(resp->sa, sdata->vif.addr, ETH_ALEN);
    	memcpy(resp->bssid, sdata->u.mgd.bssid, ETH_ALEN);
    	resp->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
    					  IEEE80211_STYPE_ACTION);
    	skb_put(skb, 1 + sizeof(resp->u.action.u.sa_query));
    	resp->u.action.category = WLAN_CATEGORY_SA_QUERY;
    	resp->u.action.u.sa_query.action = WLAN_ACTION_SA_QUERY_RESPONSE;
    	memcpy(resp->u.action.u.sa_query.trans_id,
    	       mgmt->u.action.u.sa_query.trans_id,
    	       WLAN_SA_QUERY_TR_ID_LEN);
    
    	ieee80211_tx_skb(sdata, skb);
    }
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_mgmt_check(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
    
    	/*
    	 * From here on, look only at management frames.
    	 * Data and control frames are already handled,
    	 * and unknown (reserved) frames are useless.
    	 */
    	if (rx->skb->len < 24)
    		return RX_DROP_MONITOR;
    
    	if (!ieee80211_is_mgmt(mgmt->frame_control))
    		return RX_DROP_MONITOR;
    
    	if (rx->sdata->vif.type == NL80211_IFTYPE_AP &&
    	    ieee80211_is_beacon(mgmt->frame_control) &&
    	    !(rx->flags & IEEE80211_RX_BEACON_REPORTED)) {
    		int sig = 0;
    
    		if (rx->local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
    			sig = status->signal;
    
    		cfg80211_report_obss_beacon(rx->local->hw.wiphy,
    					    rx->skb->data, rx->skb->len,
    					    status->freq, sig);
    		rx->flags |= IEEE80211_RX_BEACON_REPORTED;
    	}
    
    	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
    		return RX_DROP_MONITOR;
    
    	if (ieee80211_drop_unencrypted_mgmt(rx))
    		return RX_DROP_UNUSABLE;
    
    	return RX_CONTINUE;
    }
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_action(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_local *local = rx->local;
    	struct ieee80211_sub_if_data *sdata = rx->sdata;
    	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
    	int len = rx->skb->len;
    
    	if (!ieee80211_is_action(mgmt->frame_control))
    		return RX_CONTINUE;
    
    	/* drop too small frames */
    	if (len < IEEE80211_MIN_ACTION_SIZE)
    		return RX_DROP_UNUSABLE;
    
    	if (!rx->sta && mgmt->u.action.category != WLAN_CATEGORY_PUBLIC &&
    	    mgmt->u.action.category != WLAN_CATEGORY_SELF_PROTECTED &&
    	    mgmt->u.action.category != WLAN_CATEGORY_SPECTRUM_MGMT)
    		return RX_DROP_UNUSABLE;
    
    	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
    		return RX_DROP_UNUSABLE;
    
    	switch (mgmt->u.action.category) {
    	case WLAN_CATEGORY_HT:
    		/* reject HT action frames from stations not supporting HT */
    		if (!rx->sta->sta.ht_cap.ht_supported)
    			goto invalid;
    
    		if (sdata->vif.type != NL80211_IFTYPE_STATION &&
    		    sdata->vif.type != NL80211_IFTYPE_MESH_POINT &&
    		    sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
    		    sdata->vif.type != NL80211_IFTYPE_AP &&
    		    sdata->vif.type != NL80211_IFTYPE_ADHOC)
    			break;
    
    		/* verify action & smps_control/chanwidth are present */
    		if (len < IEEE80211_MIN_ACTION_SIZE + 2)
    			goto invalid;
    
    		switch (mgmt->u.action.u.ht_smps.action) {
    		case WLAN_HT_ACTION_SMPS: {
    			struct ieee80211_supported_band *sband;
    			enum ieee80211_smps_mode smps_mode;
    
    			/* convert to HT capability */
    			switch (mgmt->u.action.u.ht_smps.smps_control) {
    			case WLAN_HT_SMPS_CONTROL_DISABLED:
    				smps_mode = IEEE80211_SMPS_OFF;
    				break;
    			case WLAN_HT_SMPS_CONTROL_STATIC:
    				smps_mode = IEEE80211_SMPS_STATIC;
    				break;
    			case WLAN_HT_SMPS_CONTROL_DYNAMIC:
    				smps_mode = IEEE80211_SMPS_DYNAMIC;
    				break;
    			default:
    				goto invalid;
    			}
    
    			/* if no change do nothing */
    			if (rx->sta->sta.smps_mode == smps_mode)
    				goto handled;
    			rx->sta->sta.smps_mode = smps_mode;
    
    			sband = rx->local->hw.wiphy->bands[status->band];
    
    			rate_control_rate_update(local, sband, rx->sta,
    						 IEEE80211_RC_SMPS_CHANGED);
    			goto handled;
    		}
    		case WLAN_HT_ACTION_NOTIFY_CHANWIDTH: {
    			struct ieee80211_supported_band *sband;
    			u8 chanwidth = mgmt->u.action.u.ht_notify_cw.chanwidth;
    			enum ieee80211_sta_rx_bandwidth new_bw;
    
    			/* If it doesn't support 40 MHz it can't change ... */
    			if (!(rx->sta->sta.ht_cap.cap &
    					IEEE80211_HT_CAP_SUP_WIDTH_20_40))
    				goto handled;
    
    			if (chanwidth == IEEE80211_HT_CHANWIDTH_20MHZ)
    				new_bw = IEEE80211_STA_RX_BW_20;
    			else
    				new_bw = ieee80211_sta_cur_vht_bw(rx->sta);
    
    			if (rx->sta->sta.bandwidth == new_bw)
    				goto handled;
    
    			sband = rx->local->hw.wiphy->bands[status->band];
    
    			rate_control_rate_update(local, sband, rx->sta,
    						 IEEE80211_RC_BW_CHANGED);
    			goto handled;
    		}
    		default:
    			goto invalid;
    		}
    
    		break;
    	case WLAN_CATEGORY_PUBLIC:
    		if (len < IEEE80211_MIN_ACTION_SIZE + 1)
    			goto invalid;
    		if (sdata->vif.type != NL80211_IFTYPE_STATION)
    			break;
    		if (!rx->sta)
    			break;
    		if (!ether_addr_equal(mgmt->bssid, sdata->u.mgd.bssid))
    			break;
    		if (mgmt->u.action.u.ext_chan_switch.action_code !=
    				WLAN_PUB_ACTION_EXT_CHANSW_ANN)
    			break;
    		if (len < offsetof(struct ieee80211_mgmt,
    				   u.action.u.ext_chan_switch.variable))
    			goto invalid;
    		goto queue;
    	case WLAN_CATEGORY_VHT:
    		if (sdata->vif.type != NL80211_IFTYPE_STATION &&
    		    sdata->vif.type != NL80211_IFTYPE_MESH_POINT &&
    		    sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
    		    sdata->vif.type != NL80211_IFTYPE_AP &&
    		    sdata->vif.type != NL80211_IFTYPE_ADHOC)
    			break;
    
    		/* verify action code is present */
    		if (len < IEEE80211_MIN_ACTION_SIZE + 1)
    			goto invalid;
    
    		switch (mgmt->u.action.u.vht_opmode_notif.action_code) {
    		case WLAN_VHT_ACTION_OPMODE_NOTIF: {
    			u8 opmode;
    
    			/* verify opmode is present */
    			if (len < IEEE80211_MIN_ACTION_SIZE + 2)
    				goto invalid;
    
    			opmode = mgmt->u.action.u.vht_opmode_notif.operating_mode;
    
    			ieee80211_vht_handle_opmode(rx->sdata, rx->sta,
    						    opmode, status->band,
    						    false);
    			goto handled;
    		}
    		default:
    			break;
    		}
    		break;
    	case WLAN_CATEGORY_BACK:
    		if (sdata->vif.type != NL80211_IFTYPE_STATION &&
    		    sdata->vif.type != NL80211_IFTYPE_MESH_POINT &&
    		    sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
    		    sdata->vif.type != NL80211_IFTYPE_AP &&
    		    sdata->vif.type != NL80211_IFTYPE_ADHOC)
    			break;
    
    		/* verify action_code is present */
    		if (len < IEEE80211_MIN_ACTION_SIZE + 1)
    			break;
    
    		switch (mgmt->u.action.u.addba_req.action_code) {
    		case WLAN_ACTION_ADDBA_REQ:
    			if (len < (IEEE80211_MIN_ACTION_SIZE +
    				   sizeof(mgmt->u.action.u.addba_req)))
    				goto invalid;
    			break;
    		case WLAN_ACTION_ADDBA_RESP:
    			if (len < (IEEE80211_MIN_ACTION_SIZE +
    				   sizeof(mgmt->u.action.u.addba_resp)))
    				goto invalid;
    			break;
    		case WLAN_ACTION_DELBA:
    			if (len < (IEEE80211_MIN_ACTION_SIZE +
    				   sizeof(mgmt->u.action.u.delba)))
    				goto invalid;
    			break;
    		default:
    			goto invalid;
    		}
    
    		goto queue;
    	case WLAN_CATEGORY_SPECTRUM_MGMT:
    		/* verify action_code is present */
    		if (len < IEEE80211_MIN_ACTION_SIZE + 1)
    			break;
    
    		switch (mgmt->u.action.u.measurement.action_code) {
    		case WLAN_ACTION_SPCT_MSR_REQ:
    			if (status->band != IEEE80211_BAND_5GHZ)
    				break;
    
    			if (len < (IEEE80211_MIN_ACTION_SIZE +
    				   sizeof(mgmt->u.action.u.measurement)))
    				break;
    
    			if (sdata->vif.type != NL80211_IFTYPE_STATION)
    				break;
    
    			ieee80211_process_measurement_req(sdata, mgmt, len);
    			goto handled;
    		case WLAN_ACTION_SPCT_CHL_SWITCH: {
    			u8 *bssid;
    			if (len < (IEEE80211_MIN_ACTION_SIZE +
    				   sizeof(mgmt->u.action.u.chan_switch)))
    				break;
    
    			if (sdata->vif.type != NL80211_IFTYPE_STATION &&
    			    sdata->vif.type != NL80211_IFTYPE_ADHOC &&
    			    sdata->vif.type != NL80211_IFTYPE_MESH_POINT)
    				break;
    
    			if (sdata->vif.type == NL80211_IFTYPE_STATION)
    				bssid = sdata->u.mgd.bssid;
    			else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
    				bssid = sdata->u.ibss.bssid;
    			else if (sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
    				bssid = mgmt->sa;
    			else
    				break;
    
    			if (!ether_addr_equal(mgmt->bssid, bssid))
    				break;
    
    			goto queue;
    			}
    		}
    		break;
    	case WLAN_CATEGORY_SA_QUERY:
    		if (len < (IEEE80211_MIN_ACTION_SIZE +
    			   sizeof(mgmt->u.action.u.sa_query)))
    			break;
    
    		switch (mgmt->u.action.u.sa_query.action) {
    		case WLAN_ACTION_SA_QUERY_REQUEST:
    			if (sdata->vif.type != NL80211_IFTYPE_STATION)
    				break;
    			ieee80211_process_sa_query_req(sdata, mgmt, len);
    			goto handled;
    		}
    		break;
    	case WLAN_CATEGORY_SELF_PROTECTED:
    		if (len < (IEEE80211_MIN_ACTION_SIZE +
    			   sizeof(mgmt->u.action.u.self_prot.action_code)))
    			break;
    
    		switch (mgmt->u.action.u.self_prot.action_code) {
    		case WLAN_SP_MESH_PEERING_OPEN:
    		case WLAN_SP_MESH_PEERING_CLOSE:
    		case WLAN_SP_MESH_PEERING_CONFIRM:
    			if (!ieee80211_vif_is_mesh(&sdata->vif))
    				goto invalid;
    			if (sdata->u.mesh.user_mpm)
    				/* userspace handles this frame */
    				break;
    			goto queue;
    		case WLAN_SP_MGK_INFORM:
    		case WLAN_SP_MGK_ACK:
    			if (!ieee80211_vif_is_mesh(&sdata->vif))
    				goto invalid;
    			break;
    		}
    		break;
    	case WLAN_CATEGORY_MESH_ACTION:
    		if (len < (IEEE80211_MIN_ACTION_SIZE +
    			   sizeof(mgmt->u.action.u.mesh_action.action_code)))
    			break;
    
    		if (!ieee80211_vif_is_mesh(&sdata->vif))
    			break;
    		if (mesh_action_is_path_sel(mgmt) &&
    		    !mesh_path_sel_is_hwmp(sdata))
    			break;
    		goto queue;
    	}
    
    	return RX_CONTINUE;
    
     invalid:
    	status->rx_flags |= IEEE80211_RX_MALFORMED_ACTION_FRM;
    	/* will return in the next handlers */
    	return RX_CONTINUE;
    
     handled:
    	if (rx->sta)
    		rx->sta->rx_packets++;
    	dev_kfree_skb(rx->skb);
    	return RX_QUEUED;
    
     queue:
    	rx->skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
    	skb_queue_tail(&sdata->skb_queue, rx->skb);
    	ieee80211_queue_work(&local->hw, &sdata->work);
    	if (rx->sta)
    		rx->sta->rx_packets++;
    	return RX_QUEUED;
    }
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_userspace_mgmt(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
    	int sig = 0;
    
    	/* skip known-bad action frames and return them in the next handler */
    	if (status->rx_flags & IEEE80211_RX_MALFORMED_ACTION_FRM)
    		return RX_CONTINUE;
    
    	/*
    	 * Getting here means the kernel doesn't know how to handle
    	 * it, but maybe userspace does ... include returned frames
    	 * so userspace can register for those to know whether ones
    	 * it transmitted were processed or returned.
    	 */
    
    	if (rx->local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
    		sig = status->signal;
    
    	if (cfg80211_rx_mgmt(&rx->sdata->wdev, status->freq, sig,
    			     rx->skb->data, rx->skb->len, 0, GFP_ATOMIC)) {
    		if (rx->sta)
    			rx->sta->rx_packets++;
    		dev_kfree_skb(rx->skb);
    		return RX_QUEUED;
    	}
    
    	return RX_CONTINUE;
    }
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_action_return(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_local *local = rx->local;
    	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
    	struct sk_buff *nskb;
    	struct ieee80211_sub_if_data *sdata = rx->sdata;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
    
    	if (!ieee80211_is_action(mgmt->frame_control))
    		return RX_CONTINUE;
    
    	/*
    	 * For AP mode, hostapd is responsible for handling any action
    	 * frames that we didn't handle, including returning unknown
    	 * ones. For all other modes we will return them to the sender,
    	 * setting the 0x80 bit in the action category, as required by
    	 * 802.11-2012 9.24.4.
    	 * Newer versions of hostapd shall also use the management frame
    	 * registration mechanisms, but older ones still use cooked
    	 * monitor interfaces so push all frames there.
    	 */
    	if (!(status->rx_flags & IEEE80211_RX_MALFORMED_ACTION_FRM) &&
    	    (sdata->vif.type == NL80211_IFTYPE_AP ||
    	     sdata->vif.type == NL80211_IFTYPE_AP_VLAN))
    		return RX_DROP_MONITOR;
    
    	if (is_multicast_ether_addr(mgmt->da))
    		return RX_DROP_MONITOR;
    
    	/* do not return rejected action frames */
    	if (mgmt->u.action.category & 0x80)
    		return RX_DROP_UNUSABLE;
    
    	nskb = skb_copy_expand(rx->skb, local->hw.extra_tx_headroom, 0,
    			       GFP_ATOMIC);
    	if (nskb) {
    		struct ieee80211_mgmt *nmgmt = (void *)nskb->data;
    
    		nmgmt->u.action.category |= 0x80;
    		memcpy(nmgmt->da, nmgmt->sa, ETH_ALEN);
    		memcpy(nmgmt->sa, rx->sdata->vif.addr, ETH_ALEN);
    
    		memset(nskb->cb, 0, sizeof(nskb->cb));
    
    		if (rx->sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE) {
    			struct ieee80211_tx_info *info = IEEE80211_SKB_CB(nskb);
    
    			info->flags = IEEE80211_TX_CTL_TX_OFFCHAN |
    				      IEEE80211_TX_INTFL_OFFCHAN_TX_OK |
    				      IEEE80211_TX_CTL_NO_CCK_RATE;
    			if (local->hw.flags & IEEE80211_HW_QUEUE_CONTROL)
    				info->hw_queue =
    					local->hw.offchannel_tx_hw_queue;
    		}
    
    		__ieee80211_tx_skb_tid_band(rx->sdata, nskb, 7,
    					    status->band);
    	}
    	dev_kfree_skb(rx->skb);
    	return RX_QUEUED;
    }
    
    static ieee80211_rx_result debug_noinline
    ieee80211_rx_h_mgmt(struct ieee80211_rx_data *rx)
    {
    	struct ieee80211_sub_if_data *sdata = rx->sdata;
    	struct ieee80211_mgmt *mgmt = (void *)rx->skb->data;
    	__le16 stype;
    
    	stype = mgmt->frame_control & cpu_to_le16(IEEE80211_FCTL_STYPE);
    
    	if (!ieee80211_vif_is_mesh(&sdata->vif) &&
    	    sdata->vif.type != NL80211_IFTYPE_ADHOC &&
    	    sdata->vif.type != NL80211_IFTYPE_STATION)
    		return RX_DROP_MONITOR;
    
    	switch (stype) {
    	case cpu_to_le16(IEEE80211_STYPE_AUTH):
    	case cpu_to_le16(IEEE80211_STYPE_BEACON):
    	case cpu_to_le16(IEEE80211_STYPE_PROBE_RESP):
    		/* process for all: mesh, mlme, ibss */
    		break;
    	case cpu_to_le16(IEEE80211_STYPE_ASSOC_RESP):
    	case cpu_to_le16(IEEE80211_STYPE_REASSOC_RESP):
    	case cpu_to_le16(IEEE80211_STYPE_DEAUTH):
    	case cpu_to_le16(IEEE80211_STYPE_DISASSOC):
    		if (is_multicast_ether_addr(mgmt->da) &&
    		    !is_broadcast_ether_addr(mgmt->da))
    			return RX_DROP_MONITOR;
    
    		/* process only for station */
    		if (sdata->vif.type != NL80211_IFTYPE_STATION)
    			return RX_DROP_MONITOR;
    		break;
    	case cpu_to_le16(IEEE80211_STYPE_PROBE_REQ):
    		/* process only for ibss and mesh */
    		if (sdata->vif.type != NL80211_IFTYPE_ADHOC &&
    		    sdata->vif.type != NL80211_IFTYPE_MESH_POINT)
    			return RX_DROP_MONITOR;
    		break;
    	default:
    		return RX_DROP_MONITOR;
    	}
    
    	/* queue up frame and kick off work to process it */
    	rx->skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
    	skb_queue_tail(&sdata->skb_queue, rx->skb);
    	ieee80211_queue_work(&rx->local->hw, &sdata->work);
    	if (rx->sta)
    		rx->sta->rx_packets++;
    
    	return RX_QUEUED;
    }
    
    /* TODO: use IEEE80211_RX_FRAGMENTED */
    static void ieee80211_rx_cooked_monitor(struct ieee80211_rx_data *rx,
    					struct ieee80211_rate *rate)
    {
    	struct ieee80211_sub_if_data *sdata;
    	struct ieee80211_local *local = rx->local;
    	struct sk_buff *skb = rx->skb, *skb2;
    	struct net_device *prev_dev = NULL;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
    	int needed_headroom;
    
    	/*
    	 * If cooked monitor has been processed already, then
    	 * don't do it again. If not, set the flag.
    	 */
    	if (rx->flags & IEEE80211_RX_CMNTR)
    		goto out_free_skb;
    	rx->flags |= IEEE80211_RX_CMNTR;
    
    	/* If there are no cooked monitor interfaces, just free the SKB */
    	if (!local->cooked_mntrs)
    		goto out_free_skb;
    
    	/* room for the radiotap header based on driver features */
    	needed_headroom = ieee80211_rx_radiotap_space(local, status);
    
    	if (skb_headroom(skb) < needed_headroom &&
    	    pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC))
    		goto out_free_skb;
    
    	/* prepend radiotap information */
    	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom,
    					 false);
    
    	skb_set_mac_header(skb, 0);
    	skb->ip_summed = CHECKSUM_UNNECESSARY;
    	skb->pkt_type = PACKET_OTHERHOST;
    	skb->protocol = htons(ETH_P_802_2);
    
    	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
    		if (!ieee80211_sdata_running(sdata))
    			continue;
    
    		if (sdata->vif.type != NL80211_IFTYPE_MONITOR ||
    		    !(sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES))
    			continue;
    
    		if (prev_dev) {
    			skb2 = skb_clone(skb, GFP_ATOMIC);
    			if (skb2) {
    				skb2->dev = prev_dev;
    				netif_receive_skb(skb2);
    			}
    		}
    
    		prev_dev = sdata->dev;
    		sdata->dev->stats.rx_packets++;
    		sdata->dev->stats.rx_bytes += skb->len;
    	}
    
    	if (prev_dev) {
    		skb->dev = prev_dev;
    		netif_receive_skb(skb);
    		return;
    	}
    
     out_free_skb:
    	dev_kfree_skb(skb);
    }
    
    static void ieee80211_rx_handlers_result(struct ieee80211_rx_data *rx,
    					 ieee80211_rx_result res)
    {
    	switch (res) {
    	case RX_DROP_MONITOR:
    		I802_DEBUG_INC(rx->sdata->local->rx_handlers_drop);
    		if (rx->sta)
    			rx->sta->rx_dropped++;
    		/* fall through */
    	case RX_CONTINUE: {
    		struct ieee80211_rate *rate = NULL;
    		struct ieee80211_supported_band *sband;
    		struct ieee80211_rx_status *status;
    
    		status = IEEE80211_SKB_RXCB((rx->skb));
    
    		sband = rx->local->hw.wiphy->bands[status->band];
    		if (!(status->flag & RX_FLAG_HT) &&
    		    !(status->flag & RX_FLAG_VHT))
    			rate = &sband->bitrates[status->rate_idx];
    
    		ieee80211_rx_cooked_monitor(rx, rate);
    		break;
    		}
    	case RX_DROP_UNUSABLE:
    		I802_DEBUG_INC(rx->sdata->local->rx_handlers_drop);
    		if (rx->sta)
    			rx->sta->rx_dropped++;
    		dev_kfree_skb(rx->skb);
    		break;
    	case RX_QUEUED:
    		I802_DEBUG_INC(rx->sdata->local->rx_handlers_queued);
    		break;
    	}
    }
    
    static void ieee80211_rx_handlers(struct ieee80211_rx_data *rx,
    				  struct sk_buff_head *frames)
    {
    	ieee80211_rx_result res = RX_DROP_MONITOR;
    	struct sk_buff *skb;
    
    #define CALL_RXH(rxh)			\
    	do {				\
    		res = rxh(rx);		\
    		if (res != RX_CONTINUE)	\
    			goto rxh_next;  \
    	} while (0);
    
    	spin_lock_bh(&rx->local->rx_path_lock);
    
    	while ((skb = __skb_dequeue(frames))) {
    		/*
    		 * all the other fields are valid across frames
    		 * that belong to an aMPDU since they are on the
    		 * same TID from the same station
    		 */
    		rx->skb = skb;
    
    		CALL_RXH(ieee80211_rx_h_check_more_data)
    		CALL_RXH(ieee80211_rx_h_uapsd_and_pspoll)
    		CALL_RXH(ieee80211_rx_h_sta_process)
    		CALL_RXH(ieee80211_rx_h_decrypt)
    		CALL_RXH(ieee80211_rx_h_defragment)
    		CALL_RXH(ieee80211_rx_h_michael_mic_verify)
    		/* must be after MMIC verify so header is counted in MPDU mic */
    #ifdef CONFIG_MAC80211_MESH
    		if (ieee80211_vif_is_mesh(&rx->sdata->vif))
    			CALL_RXH(ieee80211_rx_h_mesh_fwding);
    #endif
    		CALL_RXH(ieee80211_rx_h_amsdu)
    		CALL_RXH(ieee80211_rx_h_data)
    
    		/* special treatment -- needs the queue */
    		res = ieee80211_rx_h_ctrl(rx, frames);
    		if (res != RX_CONTINUE)
    			goto rxh_next;
    
    		CALL_RXH(ieee80211_rx_h_mgmt_check)
    		CALL_RXH(ieee80211_rx_h_action)
    		CALL_RXH(ieee80211_rx_h_userspace_mgmt)
    		CALL_RXH(ieee80211_rx_h_action_return)
    		CALL_RXH(ieee80211_rx_h_mgmt)
    
     rxh_next:
    		ieee80211_rx_handlers_result(rx, res);
    
    #undef CALL_RXH
    	}
    
    	spin_unlock_bh(&rx->local->rx_path_lock);
    }
    
    static void ieee80211_invoke_rx_handlers(struct ieee80211_rx_data *rx)
    {
    	struct sk_buff_head reorder_release;
    	ieee80211_rx_result res = RX_DROP_MONITOR;
    
    	__skb_queue_head_init(&reorder_release);
    
    #define CALL_RXH(rxh)			\
    	do {				\
    		res = rxh(rx);		\
    		if (res != RX_CONTINUE)	\
    			goto rxh_next;  \
    	} while (0);
    
    	CALL_RXH(ieee80211_rx_h_check)
    
    	ieee80211_rx_reorder_ampdu(rx, &reorder_release);
    
    	ieee80211_rx_handlers(rx, &reorder_release);
    	return;
    
     rxh_next:
    	ieee80211_rx_handlers_result(rx, res);
    
    #undef CALL_RXH
    }
    
    /*
     * This function makes calls into the RX path, therefore
     * it has to be invoked under RCU read lock.
     */
    void ieee80211_release_reorder_timeout(struct sta_info *sta, int tid)
    {
    	struct sk_buff_head frames;
    	struct ieee80211_rx_data rx = {
    		.sta = sta,
    		.sdata = sta->sdata,
    		.local = sta->local,
    		/* This is OK -- must be QoS data frame */
    		.security_idx = tid,
    		.seqno_idx = tid,
    		.flags = 0,
    	};
    	struct tid_ampdu_rx *tid_agg_rx;
    
    	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
    	if (!tid_agg_rx)
    		return;
    
    	__skb_queue_head_init(&frames);
    
    	spin_lock(&tid_agg_rx->reorder_lock);
    	ieee80211_sta_reorder_release(sta->sdata, tid_agg_rx, &frames);
    	spin_unlock(&tid_agg_rx->reorder_lock);
    
    	ieee80211_rx_handlers(&rx, &frames);
    }
    
    /* main receive path */
    
    static bool prepare_for_handlers(struct ieee80211_rx_data *rx,
    				 struct ieee80211_hdr *hdr)
    {
    	struct ieee80211_sub_if_data *sdata = rx->sdata;
    	struct sk_buff *skb = rx->skb;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
    	u8 *bssid = ieee80211_get_bssid(hdr, skb->len, sdata->vif.type);
    	int multicast = is_multicast_ether_addr(hdr->addr1);
    
    	switch (sdata->vif.type) {
    	case NL80211_IFTYPE_STATION:
    		if (!bssid && !sdata->u.mgd.use_4addr)
    			return false;
    		if (!multicast &&
    		    !ether_addr_equal(sdata->vif.addr, hdr->addr1)) {
    			if (!(sdata->dev->flags & IFF_PROMISC) ||
    			    sdata->u.mgd.use_4addr)
    				return false;
    			status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
    		}
    		break;
    	case NL80211_IFTYPE_ADHOC:
    		if (!bssid)
    			return false;
    		if (ether_addr_equal(sdata->vif.addr, hdr->addr2) ||
    		    ether_addr_equal(sdata->u.ibss.bssid, hdr->addr2))
    			return false;
    		if (ieee80211_is_beacon(hdr->frame_control)) {
    			return true;
    		} else if (!ieee80211_bssid_match(bssid, sdata->u.ibss.bssid)) {
    			return false;
    		} else if (!multicast &&
    			   !ether_addr_equal(sdata->vif.addr, hdr->addr1)) {
    			if (!(sdata->dev->flags & IFF_PROMISC))
    				return false;
    			status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
    		} else if (!rx->sta) {
    			int rate_idx;
    			if (status->flag & (RX_FLAG_HT | RX_FLAG_VHT))
    				rate_idx = 0; /* TODO: HT/VHT rates */
    			else
    				rate_idx = status->rate_idx;
    			ieee80211_ibss_rx_no_sta(sdata, bssid, hdr->addr2,
    						 BIT(rate_idx));
    		}
    		break;
    	case NL80211_IFTYPE_MESH_POINT:
    		if (!multicast &&
    		    !ether_addr_equal(sdata->vif.addr, hdr->addr1)) {
    			if (!(sdata->dev->flags & IFF_PROMISC))
    				return false;
    
    			status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
    		}
    		break;
    	case NL80211_IFTYPE_AP_VLAN:
    	case NL80211_IFTYPE_AP:
    		if (!bssid) {
    			if (!ether_addr_equal(sdata->vif.addr, hdr->addr1))
    				return false;
    		} else if (!ieee80211_bssid_match(bssid, sdata->vif.addr)) {
    			/*
    			 * Accept public action frames even when the
    			 * BSSID doesn't match, this is used for P2P
    			 * and location updates. Note that mac80211
    			 * itself never looks at these frames.
    			 */
    			if (!multicast &&
    			    !ether_addr_equal(sdata->vif.addr, hdr->addr1))
    				return false;
    			if (ieee80211_is_public_action(hdr, skb->len))
    				return true;
    			if (!ieee80211_is_beacon(hdr->frame_control))
    				return false;
    			status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
    		}
    		break;
    	case NL80211_IFTYPE_WDS:
    		if (bssid || !ieee80211_is_data(hdr->frame_control))
    			return false;
    		if (!ether_addr_equal(sdata->u.wds.remote_addr, hdr->addr2))
    			return false;
    		break;
    	case NL80211_IFTYPE_P2P_DEVICE:
    		if (!ieee80211_is_public_action(hdr, skb->len) &&
    		    !ieee80211_is_probe_req(hdr->frame_control) &&
    		    !ieee80211_is_probe_resp(hdr->frame_control) &&
    		    !ieee80211_is_beacon(hdr->frame_control))
    			return false;
    		if (!ether_addr_equal(sdata->vif.addr, hdr->addr1) &&
    		    !multicast)
    			status->rx_flags &= ~IEEE80211_RX_RA_MATCH;
    		break;
    	default:
    		/* should never get here */
    		WARN_ON_ONCE(1);
    		break;
    	}
    
    	return true;
    }
    
    /*
     * This function returns whether or not the SKB
     * was destined for RX processing or not, which,
     * if consume is true, is equivalent to whether
     * or not the skb was consumed.
     */
    static bool ieee80211_prepare_and_rx_handle(struct ieee80211_rx_data *rx,
    					    struct sk_buff *skb, bool consume)
    {
    	struct ieee80211_local *local = rx->local;
    	struct ieee80211_sub_if_data *sdata = rx->sdata;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
    	struct ieee80211_hdr *hdr = (void *)skb->data;
    
    	rx->skb = skb;
    	status->rx_flags |= IEEE80211_RX_RA_MATCH;
    
    	if (!prepare_for_handlers(rx, hdr))
    		return false;
    
    	if (!consume) {
    		skb = skb_copy(skb, GFP_ATOMIC);
    		if (!skb) {
    			if (net_ratelimit())
    				wiphy_debug(local->hw.wiphy,
    					"failed to copy skb for %s\n",
    					sdata->name);
    			return true;
    		}
    
    		rx->skb = skb;
    	}
    
    	ieee80211_invoke_rx_handlers(rx);
    	return true;
    }
    
    /*
     * This is the actual Rx frames handler. as it blongs to Rx path it must
     * be called with rcu_read_lock protection.
     */
    static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
    					 struct sk_buff *skb)
    {
    	struct ieee80211_local *local = hw_to_local(hw);
    	struct ieee80211_sub_if_data *sdata;
    	struct ieee80211_hdr *hdr;
    	__le16 fc;
    	struct ieee80211_rx_data rx;
    	struct ieee80211_sub_if_data *prev;
    	struct sta_info *sta, *tmp, *prev_sta;
    	int err = 0;
    
    	fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
    	memset(&rx, 0, sizeof(rx));
    	rx.skb = skb;
    	rx.local = local;
    
    	if (ieee80211_is_data(fc) || ieee80211_is_mgmt(fc))
    		local->dot11ReceivedFragmentCount++;
    
    	if (ieee80211_is_mgmt(fc)) {
    		/* drop frame if too short for header */
    		if (skb->len < ieee80211_hdrlen(fc))
    			err = -ENOBUFS;
    		else
    			err = skb_linearize(skb);
    	} else {
    		err = !pskb_may_pull(skb, ieee80211_hdrlen(fc));
    	}
    
    	if (err) {
    		dev_kfree_skb(skb);
    		return;
    	}
    
    	hdr = (struct ieee80211_hdr *)skb->data;
    	ieee80211_parse_qos(&rx);
    	ieee80211_verify_alignment(&rx);
    
    	if (unlikely(ieee80211_is_probe_resp(hdr->frame_control) ||
    		     ieee80211_is_beacon(hdr->frame_control)))
    		ieee80211_scan_rx(local, skb);
    
    	if (ieee80211_is_data(fc)) {
    		prev_sta = NULL;
    
    		for_each_sta_info(local, hdr->addr2, sta, tmp) {
    			if (!prev_sta) {
    				prev_sta = sta;
    				continue;
    			}
    
    			rx.sta = prev_sta;
    			rx.sdata = prev_sta->sdata;
    			ieee80211_prepare_and_rx_handle(&rx, skb, false);
    
    			prev_sta = sta;
    		}
    
    		if (prev_sta) {
    			rx.sta = prev_sta;
    			rx.sdata = prev_sta->sdata;
    
    			if (ieee80211_prepare_and_rx_handle(&rx, skb, true))
    				return;
    			goto out;
    		}
    	}
    
    	prev = NULL;
    
    	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
    		if (!ieee80211_sdata_running(sdata))
    			continue;
    
    		if (sdata->vif.type == NL80211_IFTYPE_MONITOR ||
    		    sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
    			continue;
    
    		/*
    		 * frame is destined for this interface, but if it's
    		 * not also for the previous one we handle that after
    		 * the loop to avoid copying the SKB once too much
    		 */
    
    		if (!prev) {
    			prev = sdata;
    			continue;
    		}
    
    		rx.sta = sta_info_get_bss(prev, hdr->addr2);
    		rx.sdata = prev;
    		ieee80211_prepare_and_rx_handle(&rx, skb, false);
    
    		prev = sdata;
    	}
    
    	if (prev) {
    		rx.sta = sta_info_get_bss(prev, hdr->addr2);
    		rx.sdata = prev;
    
    		if (ieee80211_prepare_and_rx_handle(&rx, skb, true))
    			return;
    	}
    
     out:
    	dev_kfree_skb(skb);
    }
    
    /*
     * This is the receive path handler. It is called by a low level driver when an
     * 802.11 MPDU is received from the hardware.
     */
    void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb)
    {
    	struct ieee80211_local *local = hw_to_local(hw);
    	struct ieee80211_rate *rate = NULL;
    	struct ieee80211_supported_band *sband;
    	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
    
    	WARN_ON_ONCE(softirq_count() == 0);
    
    	if (WARN_ON(status->band >= IEEE80211_NUM_BANDS))
    		goto drop;
    
    	sband = local->hw.wiphy->bands[status->band];
    	if (WARN_ON(!sband))
    		goto drop;
    
    	/*
    	 * If we're suspending, it is possible although not too likely
    	 * that we'd be receiving frames after having already partially
    	 * quiesced the stack. We can't process such frames then since
    	 * that might, for example, cause stations to be added or other
    	 * driver callbacks be invoked.
    	 */
    	if (unlikely(local->quiescing || local->suspended))
    		goto drop;
    
    	/* We might be during a HW reconfig, prevent Rx for the same reason */
    	if (unlikely(local->in_reconfig))
    		goto drop;
    
    	/*
    	 * The same happens when we're not even started,
    	 * but that's worth a warning.
    	 */
    	if (WARN_ON(!local->started))
    		goto drop;
    
    	if (likely(!(status->flag & RX_FLAG_FAILED_PLCP_CRC))) {
    		/*
    		 * Validate the rate, unless a PLCP error means that
    		 * we probably can't have a valid rate here anyway.
    		 */
    
    		if (status->flag & RX_FLAG_HT) {
    			/*
    			 * rate_idx is MCS index, which can be [0-76]
    			 * as documented on:
    			 *
    			 * http://wireless.kernel.org/en/developers/Documentation/ieee80211/802.11n
    			 *
    			 * Anything else would be some sort of driver or
    			 * hardware error. The driver should catch hardware
    			 * errors.
    			 */
    			if (WARN(status->rate_idx > 76,
    				 "Rate marked as an HT rate but passed "
    				 "status->rate_idx is not "
    				 "an MCS index [0-76]: %d (0x%02x)\n",
    				 status->rate_idx,
    				 status->rate_idx))
    				goto drop;
    		} else if (status->flag & RX_FLAG_VHT) {
    			if (WARN_ONCE(status->rate_idx > 9 ||
    				      !status->vht_nss ||
    				      status->vht_nss > 8,
    				      "Rate marked as a VHT rate but data is invalid: MCS: %d, NSS: %d\n",
    				      status->rate_idx, status->vht_nss))
    				goto drop;
    		} else {
    			if (WARN_ON(status->rate_idx >= sband->n_bitrates))
    				goto drop;
    			rate = &sband->bitrates[status->rate_idx];
    		}
    	}
    
    	status->rx_flags = 0;
    
    	/*
    	 * key references and virtual interfaces are protected using RCU
    	 * and this requires that we are in a read-side RCU section during
    	 * receive processing
    	 */
    	rcu_read_lock();
    
    	/*
    	 * Frames with failed FCS/PLCP checksum are not returned,
    	 * all other frames are returned without radiotap header
    	 * if it was previously present.
    	 * Also, frames with less than 16 bytes are dropped.
    	 */
    	skb = ieee80211_rx_monitor(local, skb, rate);
    	if (!skb) {
    		rcu_read_unlock();
    		return;
    	}
    
    	ieee80211_tpt_led_trig_rx(local,
    			((struct ieee80211_hdr *)skb->data)->frame_control,
    			skb->len);
    	__ieee80211_rx_handle_packet(hw, skb);
    
    	rcu_read_unlock();
    
    	return;
     drop:
    	kfree_skb(skb);
    }
    EXPORT_SYMBOL(ieee80211_rx);
    
    /* This is a version of the rx handler that can be called from hard irq
     * context. Post the skb on the queue and schedule the tasklet */
    void ieee80211_rx_irqsafe(struct ieee80211_hw *hw, struct sk_buff *skb)
    {
    	struct ieee80211_local *local = hw_to_local(hw);
    
    	BUILD_BUG_ON(sizeof(struct ieee80211_rx_status) > sizeof(skb->cb));
    
    	skb->pkt_type = IEEE80211_RX_MSG;
    	skb_queue_tail(&local->skb_queue, skb);
    	tasklet_schedule(&local->tasklet);
    }
    EXPORT_SYMBOL(ieee80211_rx_irqsafe);