rx.c 92.2 KB
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/*
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
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 * Copyright 2007-2010	Johannes Berg <johannes@sipsolutions.net>
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 *
 * 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.
 */

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#include <linux/jiffies.h>
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#include <linux/slab.h>
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#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
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#include <linux/rcupdate.h>
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#include <linux/export.h>
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#include <net/mac80211.h>
#include <net/ieee80211_radiotap.h>
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#include <asm/unaligned.h>
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#include "ieee80211_i.h"
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#include "driver-ops.h"
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#include "led.h"
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#include "mesh.h"
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#include "wep.h"
#include "wpa.h"
#include "tkip.h"
#include "wme.h"
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#include "rate.h"
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/*
 * 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,
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					   struct sk_buff *skb)
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{
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	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);

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	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
		if (likely(skb->len > FCS_LEN))
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			__pskb_trim(skb, skb->len - FCS_LEN);
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		else {
			/* driver bug */
			WARN_ON(1);
			dev_kfree_skb(skb);
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			return NULL;
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		}
	}

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	if (status->vendor_radiotap_len)
		__pskb_pull(skb, status->vendor_radiotap_len);

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	return skb;
}

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static inline int should_drop_frame(struct sk_buff *skb, int present_fcs_len)
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{
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	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
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	struct ieee80211_hdr *hdr;

	hdr = (void *)(skb->data + status->vendor_radiotap_len);
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	if (status->flag & (RX_FLAG_FAILED_FCS_CRC |
			    RX_FLAG_FAILED_PLCP_CRC |
			    RX_FLAG_AMPDU_IS_ZEROLEN))
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		return 1;
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	if (unlikely(skb->len < 16 + present_fcs_len +
				status->vendor_radiotap_len))
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		return 1;
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	if (ieee80211_is_ctl(hdr->frame_control) &&
	    !ieee80211_is_pspoll(hdr->frame_control) &&
	    !ieee80211_is_back_req(hdr->frame_control))
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		return 1;
	return 0;
}

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static int
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ieee80211_rx_radiotap_space(struct ieee80211_local *local,
			    struct ieee80211_rx_status *status)
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{
	int len;

	/* always present fields */
	len = sizeof(struct ieee80211_radiotap_header) + 9;

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	/* allocate extra bitmap */
	if (status->vendor_radiotap_len)
		len += 4;

	if (ieee80211_have_rx_timestamp(status)) {
		len = ALIGN(len, 8);
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		len += 8;
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	}
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	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
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		len += 1;

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	/* padding for RX_FLAGS if necessary */
	len = ALIGN(len, 2);
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	if (status->flag & RX_FLAG_HT) /* HT info */
		len += 3;

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	if (status->flag & RX_FLAG_AMPDU_DETAILS) {
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		len = ALIGN(len, 4);
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		len += 8;
	}

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	if (status->flag & RX_FLAG_VHT) {
		len = ALIGN(len, 2);
		len += 12;
	}

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	if (status->vendor_radiotap_len) {
		if (WARN_ON_ONCE(status->vendor_radiotap_align == 0))
			status->vendor_radiotap_align = 1;
		/* align standard part of vendor namespace */
		len = ALIGN(len, 2);
		/* allocate standard part of vendor namespace */
		len += 6;
		/* align vendor-defined part */
		len = ALIGN(len, status->vendor_radiotap_align);
		/* vendor-defined part is already in skb */
	}

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	return len;
}

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/*
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 * 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,
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				 int rtap_len, bool has_fcs)
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{
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	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
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	struct ieee80211_radiotap_header *rthdr;
	unsigned char *pos;
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	u16 rx_flags = 0;
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	int mpdulen;

	mpdulen = skb->len;
	if (!(has_fcs && (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)))
		mpdulen += FCS_LEN;
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	rthdr = (struct ieee80211_radiotap_header *)skb_push(skb, rtap_len);
	memset(rthdr, 0, rtap_len);

	/* radiotap header, set always present flags */
	rthdr->it_present =
		cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
			    (1 << IEEE80211_RADIOTAP_CHANNEL) |
			    (1 << IEEE80211_RADIOTAP_ANTENNA) |
			    (1 << IEEE80211_RADIOTAP_RX_FLAGS));
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	rthdr->it_len = cpu_to_le16(rtap_len + status->vendor_radiotap_len);
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	pos = (unsigned char *)(rthdr + 1);
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	if (status->vendor_radiotap_len) {
		rthdr->it_present |=
			cpu_to_le32(BIT(IEEE80211_RADIOTAP_VENDOR_NAMESPACE)) |
			cpu_to_le32(BIT(IEEE80211_RADIOTAP_EXT));
		put_unaligned_le32(status->vendor_radiotap_bitmap, pos);
		pos += 4;
	}

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	/* the order of the following fields is important */

	/* IEEE80211_RADIOTAP_TSFT */
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	if (ieee80211_have_rx_timestamp(status)) {
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		/* padding */
		while ((pos - (u8 *)rthdr) & 7)
			*pos++ = 0;
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		put_unaligned_le64(
			ieee80211_calculate_rx_timestamp(local, status,
							 mpdulen, 0),
			pos);
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		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
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		pos += 8;
	}

	/* IEEE80211_RADIOTAP_FLAGS */
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	if (has_fcs && (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS))
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		*pos |= IEEE80211_RADIOTAP_F_FCS;
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	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
		*pos |= IEEE80211_RADIOTAP_F_BADFCS;
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	if (status->flag & RX_FLAG_SHORTPRE)
		*pos |= IEEE80211_RADIOTAP_F_SHORTPRE;
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	pos++;

	/* IEEE80211_RADIOTAP_RATE */
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	if (!rate || status->flag & (RX_FLAG_HT | RX_FLAG_VHT)) {
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		/*
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		 * Without rate information don't add it. If we have,
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		 * MCS information is a separate field in radiotap,
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		 * added below. The byte here is needed as padding
		 * for the channel though, so initialise it to 0.
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		 */
		*pos = 0;
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	} else {
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		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
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		*pos = rate->bitrate / 5;
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	}
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	pos++;

	/* IEEE80211_RADIOTAP_CHANNEL */
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	put_unaligned_le16(status->freq, pos);
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	pos += 2;
	if (status->band == IEEE80211_BAND_5GHZ)
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		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_5GHZ,
				   pos);
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	else if (status->flag & (RX_FLAG_HT | RX_FLAG_VHT))
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		put_unaligned_le16(IEEE80211_CHAN_DYN | IEEE80211_CHAN_2GHZ,
				   pos);
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	else if (rate && rate->flags & IEEE80211_RATE_ERP_G)
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		put_unaligned_le16(IEEE80211_CHAN_OFDM | IEEE80211_CHAN_2GHZ,
				   pos);
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	else if (rate)
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		put_unaligned_le16(IEEE80211_CHAN_CCK | IEEE80211_CHAN_2GHZ,
				   pos);
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	else
		put_unaligned_le16(IEEE80211_CHAN_2GHZ, pos);
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	pos += 2;

	/* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */
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	if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM &&
	    !(status->flag & RX_FLAG_NO_SIGNAL_VAL)) {
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		*pos = status->signal;
		rthdr->it_present |=
			cpu_to_le32(1 << IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
		pos++;
	}

	/* IEEE80211_RADIOTAP_LOCK_QUALITY is missing */

	/* 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 */
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	if ((pos - (u8 *)rthdr) & 1)
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		*pos++ = 0;
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	if (status->flag & RX_FLAG_FAILED_PLCP_CRC)
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		rx_flags |= IEEE80211_RADIOTAP_F_RX_BADPLCP;
	put_unaligned_le16(rx_flags, pos);
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	pos += 2;
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	if (status->flag & RX_FLAG_HT) {
		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
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		*pos++ = local->hw.radiotap_mcs_details;
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		*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;
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		if (status->flag & RX_FLAG_HT_GF)
			*pos |= IEEE80211_RADIOTAP_MCS_FMT_GF;
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		pos++;
		*pos++ = status->rate_idx;
	}
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	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;
	}
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	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->flag & RX_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;
		pos++;
		/* bandwidth */
		if (status->flag & RX_FLAG_80MHZ)
			*pos++ = 4;
		else if (status->flag & RX_FLAG_80P80MHZ)
			*pos++ = 0; /* marked not known above */
		else if (status->flag & RX_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 */
		pos++;
		/* group ID */
		pos++;
		/* partial_aid */
		pos += 2;
	}

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	if (status->vendor_radiotap_len) {
		/* ensure 2 byte alignment for the vendor field as required */
		if ((pos - (u8 *)rthdr) & 1)
			*pos++ = 0;
		*pos++ = status->vendor_radiotap_oui[0];
		*pos++ = status->vendor_radiotap_oui[1];
		*pos++ = status->vendor_radiotap_oui[2];
		*pos++ = status->vendor_radiotap_subns;
		put_unaligned_le16(status->vendor_radiotap_len, pos);
		pos += 2;
		/* align the actual payload as requested */
		while ((pos - (u8 *)rthdr) & (status->vendor_radiotap_align - 1))
			*pos++ = 0;
	}
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}

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/*
 * 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,
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		     struct ieee80211_rate *rate)
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{
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	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
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	struct ieee80211_sub_if_data *sdata;
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	int needed_headroom;
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	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.
	 */
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	if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
		present_fcs_len = FCS_LEN;

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	/* ensure hdr->frame_control and vendor radiotap data are in skb head */
	if (!pskb_may_pull(origskb, 2 + status->vendor_radiotap_len)) {
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		dev_kfree_skb(origskb);
		return NULL;
	}

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	if (!local->monitors) {
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		if (should_drop_frame(origskb, present_fcs_len)) {
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			dev_kfree_skb(origskb);
			return NULL;
		}

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		return remove_monitor_info(local, origskb);
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	}

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	/* room for the radiotap header based on driver features */
	needed_headroom = ieee80211_rx_radiotap_space(local, status);

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	if (should_drop_frame(origskb, present_fcs_len)) {
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		/* 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 &&
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		    pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
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			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);

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		origskb = remove_monitor_info(local, origskb);
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		if (!skb)
			return origskb;
	}

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	/* prepend radiotap information */
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	ieee80211_add_rx_radiotap_header(local, skb, rate, needed_headroom,
					 true);
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	skb_reset_mac_header(skb);
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	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) {
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		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
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			continue;

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

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		if (!ieee80211_sdata_running(sdata))
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			continue;

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

		prev_dev = sdata->dev;
		sdata->dev->stats.rx_packets++;
		sdata->dev->stats.rx_bytes += skb->len;
	}

	if (prev_dev) {
		skb->dev = prev_dev;
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		netif_receive_skb(skb);
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	} else
		dev_kfree_skb(skb);

	return origskb;
}

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static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
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{
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	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
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	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
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	int tid, seqno_idx, security_idx;
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	/* does the frame have a qos control field? */
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	if (ieee80211_is_data_qos(hdr->frame_control)) {
		u8 *qc = ieee80211_get_qos_ctl(hdr);
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		/* frame has qos control */
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		tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
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		if (*qc & IEEE80211_QOS_CTL_A_MSDU_PRESENT)
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			status->rx_flags |= IEEE80211_RX_AMSDU;
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		seqno_idx = tid;
		security_idx = tid;
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	} else {
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		/*
		 * 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.
		 */
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		seqno_idx = IEEE80211_NUM_TIDS;
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		security_idx = 0;
		if (ieee80211_is_mgmt(hdr->frame_control))
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			security_idx = IEEE80211_NUM_TIDS;
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		tid = 0;
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	}
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	rx->seqno_idx = seqno_idx;
	rx->security_idx = security_idx;
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	/* 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;
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}
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/**
 * 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
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 * 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.
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 *
 * 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.
 *
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 * Padding like Atheros hardware adds which is between the 802.11 header and
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 * 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)
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{
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#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
	WARN_ONCE((unsigned long)rx->skb->data & 1,
		  "unaligned packet at 0x%p\n", rx->skb->data);
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#endif
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}

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/* rx handlers */

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static int ieee80211_is_unicast_robust_mgmt_frame(struct sk_buff *skb)
{
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;

	if (skb->len < 24 || is_multicast_ether_addr(hdr->addr1))
		return 0;

	return ieee80211_is_robust_mgmt_frame(hdr);
}


static int ieee80211_is_multicast_robust_mgmt_frame(struct sk_buff *skb)
{
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;

	if (skb->len < 24 || !is_multicast_ether_addr(hdr->addr1))
		return 0;

	return ieee80211_is_robust_mgmt_frame(hdr);
}


/* 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;

579
	if (skb->len < 24 + sizeof(*mmie) || !is_multicast_ether_addr(hdr->da))
580 581 582 583 584 585 586 587 588 589 590 591 592 593
		return -1;

	if (!ieee80211_is_robust_mgmt_frame((struct ieee80211_hdr *) hdr))
		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);
}

594
static ieee80211_rx_result ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx)
595
{
596
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
597
	char *dev_addr = rx->sdata->vif.addr;
598

599
	if (ieee80211_is_data(hdr->frame_control)) {
600 601
		if (is_multicast_ether_addr(hdr->addr1)) {
			if (ieee80211_has_tods(hdr->frame_control) ||
602
			    !ieee80211_has_fromds(hdr->frame_control))
603
				return RX_DROP_MONITOR;
604
			if (ether_addr_equal(hdr->addr3, dev_addr))
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				return RX_DROP_MONITOR;
		} else {
			if (!ieee80211_has_a4(hdr->frame_control))
				return RX_DROP_MONITOR;
609
			if (ether_addr_equal(hdr->addr4, dev_addr))
610 611
				return RX_DROP_MONITOR;
		}
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	}

	/* If there is not an established peer link and this is not a peer link
	 * establisment frame, beacon or probe, drop the frame.
	 */

618
	if (!rx->sta || sta_plink_state(rx->sta) != NL80211_PLINK_ESTAB) {
619
		struct ieee80211_mgmt *mgmt;
620

621
		if (!ieee80211_is_mgmt(hdr->frame_control))
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			return RX_DROP_MONITOR;

624
		if (ieee80211_is_action(hdr->frame_control)) {
625
			u8 category;
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			/* make sure category field is present */
			if (rx->skb->len < IEEE80211_MIN_ACTION_SIZE)
				return RX_DROP_MONITOR;

631
			mgmt = (struct ieee80211_mgmt *)hdr;
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			category = mgmt->u.action.category;
			if (category != WLAN_CATEGORY_MESH_ACTION &&
634
			    category != WLAN_CATEGORY_SELF_PROTECTED)
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				return RX_DROP_MONITOR;
			return RX_CONTINUE;
		}

639 640
		if (ieee80211_is_probe_req(hdr->frame_control) ||
		    ieee80211_is_probe_resp(hdr->frame_control) ||
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		    ieee80211_is_beacon(hdr->frame_control) ||
		    ieee80211_is_auth(hdr->frame_control))
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			return RX_CONTINUE;

		return RX_DROP_MONITOR;
	}

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	return RX_CONTINUE;
}
650

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#define SEQ_MODULO 0x1000
#define SEQ_MASK   0xfff

static inline int seq_less(u16 sq1, u16 sq2)
{
	return ((sq1 - sq2) & SEQ_MASK) > (SEQ_MODULO >> 1);
}

static inline u16 seq_inc(u16 sq)
{
	return (sq + 1) & SEQ_MASK;
}

static inline u16 seq_sub(u16 sq1, u16 sq2)
{
	return (sq1 - sq2) & SEQ_MASK;
}

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static void ieee80211_release_reorder_frame(struct ieee80211_sub_if_data *sdata,
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					    struct tid_ampdu_rx *tid_agg_rx,
671 672
					    int index,
					    struct sk_buff_head *frames)
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{
	struct sk_buff *skb = tid_agg_rx->reorder_buf[index];
675
	struct ieee80211_rx_status *status;
676

677 678
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

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	if (!skb)
		goto no_frame;

682
	/* release the frame from the reorder ring buffer */
683 684
	tid_agg_rx->stored_mpdu_num--;
	tid_agg_rx->reorder_buf[index] = NULL;
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	status = IEEE80211_SKB_RXCB(skb);
	status->rx_flags |= IEEE80211_RX_DEFERRED_RELEASE;
687
	__skb_queue_tail(frames, skb);
688 689 690 691 692

no_frame:
	tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num);
}

693
static void ieee80211_release_reorder_frames(struct ieee80211_sub_if_data *sdata,
694
					     struct tid_ampdu_rx *tid_agg_rx,
695 696
					     u16 head_seq_num,
					     struct sk_buff_head *frames)
697 698 699
{
	int index;

700 701
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

702 703 704
	while (seq_less(tid_agg_rx->head_seq_num, head_seq_num)) {
		index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
							tid_agg_rx->buf_size;
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		ieee80211_release_reorder_frame(sdata, tid_agg_rx, index,
						frames);
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	}
}

/*
 * 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.
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 *
 * Callers must hold tid_agg_rx->reorder_lock.
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 */
#define HT_RX_REORDER_BUF_TIMEOUT (HZ / 10)

721
static void ieee80211_sta_reorder_release(struct ieee80211_sub_if_data *sdata,
722 723
					  struct tid_ampdu_rx *tid_agg_rx,
					  struct sk_buff_head *frames)
724
{
725
	int index, j;
726

727 728
	lockdep_assert_held(&tid_agg_rx->reorder_lock);

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	/* release the buffer until next missing frame */
	index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
						tid_agg_rx->buf_size;
	if (!tid_agg_rx->reorder_buf[index] &&
733
	    tid_agg_rx->stored_mpdu_num) {
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		/*
		 * 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;
			}
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			if (skipped &&
			    !time_after(jiffies, tid_agg_rx->reorder_time[j] +
747
					HT_RX_REORDER_BUF_TIMEOUT))
748
				goto set_release_timer;
749

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750 751
			ht_dbg_ratelimited(sdata,
					   "release an RX reorder frame due to timeout on earlier frames\n");
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			ieee80211_release_reorder_frame(sdata, tid_agg_rx, j,
							frames);
754 755 756 757 758 759 760 761 762

			/*
			 * Increment the head seq# also for the skipped slots.
			 */
			tid_agg_rx->head_seq_num =
				(tid_agg_rx->head_seq_num + skipped) & SEQ_MASK;
			skipped = 0;
		}
	} else while (tid_agg_rx->reorder_buf[index]) {
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		ieee80211_release_reorder_frame(sdata, tid_agg_rx, index,
						frames);
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		index =	seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) %
							tid_agg_rx->buf_size;
	}
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	if (tid_agg_rx->stored_mpdu_num) {
		j = index = seq_sub(tid_agg_rx->head_seq_num,
				    tid_agg_rx->ssn) % 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,
782
			  tid_agg_rx->reorder_time[j] + 1 +
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			  HT_RX_REORDER_BUF_TIMEOUT);
	} else {
		del_timer(&tid_agg_rx->reorder_timer);
	}
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}

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/*
 * 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.
 */
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static bool ieee80211_sta_manage_reorder_buf(struct ieee80211_sub_if_data *sdata,
795
					     struct tid_ampdu_rx *tid_agg_rx,
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					     struct sk_buff *skb,
					     struct sk_buff_head *frames)
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{
	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;
804
	bool ret = true;
805

806 807
	spin_lock(&tid_agg_rx->reorder_lock);

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	buf_size = tid_agg_rx->buf_size;
	head_seq_num = tid_agg_rx->head_seq_num;

	/* frame with out of date sequence number */
	if (seq_less(mpdu_seq_num, head_seq_num)) {
		dev_kfree_skb(skb);
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		goto out;
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	}

	/*
	 * If frame the sequence number exceeds our buffering window
	 * size release some previous frames to make room for this one.
	 */
	if (!seq_less(mpdu_seq_num, head_seq_num + buf_size)) {
		head_seq_num = seq_inc(seq_sub(mpdu_seq_num, buf_size));
		/* release stored frames up to new head to stack */
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		ieee80211_release_reorder_frames(sdata, tid_agg_rx,
825
						 head_seq_num, frames);
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	}

	/* Now the new frame is always in the range of the reordering buffer */

	index = seq_sub(mpdu_seq_num, tid_agg_rx->ssn) % tid_agg_rx->buf_size;

	/* check if we already stored this frame */
	if (tid_agg_rx->reorder_buf[index]) {
		dev_kfree_skb(skb);
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		goto out;
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	}

	/*
	 * If the current MPDU is in the right order and nothing else
	 * is stored we can process it directly, no need to buffer it.
841 842
	 * If it is first but there's something stored, we may be able
	 * to release frames after this one.
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	 */
	if (mpdu_seq_num == tid_agg_rx->head_seq_num &&
	    tid_agg_rx->stored_mpdu_num == 0) {
		tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num);
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		ret = false;
		goto out;
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	}

	/* 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++;
855
	ieee80211_sta_reorder_release(sdata, tid_agg_rx, frames);
856

857 858 859
 out:
	spin_unlock(&tid_agg_rx->reorder_lock);
	return ret;
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}

/*
 * Reorder MPDUs from A-MPDUs, keeping them on a buffer. Returns
 * true if the MPDU was buffered, false if it should be processed.
 */
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static void ieee80211_rx_reorder_ampdu(struct ieee80211_rx_data *rx,
				       struct sk_buff_head *frames)
868
{
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	struct sk_buff *skb = rx->skb;
	struct ieee80211_local *local = rx->local;
871
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
872
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
873
	struct sta_info *sta = rx->sta;
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	struct tid_ampdu_rx *tid_agg_rx;
	u16 sc;
876
	u8 tid, ack_policy;
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	if (!ieee80211_is_data_qos(hdr->frame_control))
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		goto dont_reorder;
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	/*
	 * filter the QoS data rx stream according to
	 * STA/TID and check if this STA/TID is on aggregation
	 */

	if (!sta)
887
		goto dont_reorder;
888

889 890
	ack_policy = *ieee80211_get_qos_ctl(hdr) &
		     IEEE80211_QOS_CTL_ACK_POLICY_MASK;
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	tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;

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	tid_agg_rx = rcu_dereference(sta->ampdu_mlme.tid_rx[tid]);
	if (!tid_agg_rx)
		goto dont_reorder;
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	/* qos null data frames are excluded */
	if (unlikely(hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_NULLFUNC)))
899
		goto dont_reorder;
900

901 902 903 904 905
	/* 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;

906 907 908 909
	/* not actually part of this BA session */
	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
		goto dont_reorder;

910 911 912 913
	/* new, potentially un-ordered, ampdu frame - process it */

	/* reset session timer */
	if (tid_agg_rx->timeout)
914
		tid_agg_rx->last_rx = jiffies;
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	/* if this mpdu is fragmented - terminate rx aggregation session */
	sc = le16_to_cpu(hdr->seq_ctrl);
	if (sc & IEEE80211_SCTL_FRAG) {
919
		skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
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		skb_queue_tail(&rx->sdata->skb_queue, skb);
		ieee80211_queue_work(&local->hw, &rx->sdata->work);
922
		return;
923 924
	}

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	/*
	 * 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.
	 */
932 933
	if (ieee80211_sta_manage_reorder_buf(rx->sdata, tid_agg_rx, skb,
					     frames))
934 935 936
		return;

 dont_reorder:
937
	__skb_queue_tail(frames, skb);
938
}
939

940
static ieee80211_rx_result debug_noinline
941
ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
942
{
943
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
944
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
945 946 947

	/* Drop duplicate 802.11 retransmissions (IEEE 802.11 Chap. 9.2.9) */
	if (rx->sta && !is_multicast_ether_addr(hdr->addr1)) {
948
		if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
949
			     rx->sta->last_seq_ctrl[rx->seqno_idx] ==
950
			     hdr->seq_ctrl)) {
951
			if (status->rx_flags & IEEE80211_RX_RA_MATCH) {
952 953 954
				rx->local->dot11FrameDuplicateCount++;
				rx->sta->num_duplicates++;
			}
955
			return RX_DROP_UNUSABLE;
956
		} else
957
			rx->sta->last_seq_ctrl[rx->seqno_idx] = hdr->seq_ctrl;
958 959 960 961
	}

	if (unlikely(rx->skb->len < 16)) {
		I802_DEBUG_INC(rx->local->rx_handlers_drop_short);
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		return RX_DROP_MONITOR;
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	}

	/* Drop disallowed frame classes based on STA auth/assoc state;
	 * IEEE 802.11, Chap 5.5.
	 *
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	 * mac80211 filters only based on association state, i.e. it drops
	 * Class 3 frames from not associated stations. hostapd sends
970 971 972
	 * deauth/disassoc frames when needed. In addition, hostapd is
	 * responsible for filtering on both auth and assoc states.
	 */
973

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974
	if (ieee80211_vif_is_mesh(&rx->sdata->vif))
975 976
		return ieee80211_rx_mesh_check(rx);

977 978
	if (unlikely((ieee80211_is_data(hdr->frame_control) ||
		      ieee80211_is_pspoll(hdr->frame_control)) &&
979
		     rx->sdata->vif.type != NL80211_IFTYPE_ADHOC &&
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980
		     rx->sdata->vif.type != NL80211_IFTYPE_WDS &&
981
		     (!rx->sta || !test_sta_flag(rx->sta, WLAN_STA_ASSOC)))) {
982 983 984 985 986 987
		/*
		 * 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 &&
988
		    ieee80211_is_data_present(hdr->frame_control)) {
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			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)
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				return RX_CONTINUE;
		}
1001 1002 1003 1004 1005 1006 1007

		if (rx->sdata->vif.type == NL80211_IFTYPE_AP &&
		    cfg80211_rx_spurious_frame(rx->sdata->dev,
					       hdr->addr2,
					       GFP_ATOMIC))
			return RX_DROP_UNUSABLE;

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1008
		return RX_DROP_MONITOR;
1009
	}
1010

1011
	return RX_CONTINUE;
1012 1013 1014
}


1015
static ieee80211_rx_result debug_noinline
1016
ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
1017
{
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	struct sk_buff *skb = rx->skb;
	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1021 1022
	int keyidx;
	int hdrlen;
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	ieee80211_rx_result result = RX_DROP_UNUSABLE;
1024
	struct ieee80211_key *sta_ptk = NULL;
1025
	int mmie_keyidx = -1;
1026
	__le16 fc;
1027

1028 1029 1030
	/*
	 * Key selection 101
	 *
1031
	 * There are four types of keys:
1032
	 *  - GTK (group keys)
1033
	 *  - IGTK (group keys for management frames)
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	 *  - 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
1039 1040 1041 1042
	 * 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.
1043
	 *
1044 1045 1046 1047
	 * 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.
	 *
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	 * There is also a slight problem in IBSS mode: GTKs are negotiated
	 * with each station, that is something we don't currently handle.
1050 1051 1052
	 * The spec seems to expect that one negotiates the same key with
	 * every station but there's no such requirement; VLANs could be
	 * possible.
1053 1054 1055
	 */

	/*
1056
	 * No point in finding a key and decrypting if the frame is neither
1057 1058
	 * addressed to us nor a multicast frame.
	 */
1059
	if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))