include/linux/ieee80211.h

/*
 * IEEE 802.11 defines
 *
 * Copyright (c) 2001-2002, SSH Communications Security Corp and Jouni Malinen
 * <jkmaline@cc.hut.fi>
 * Copyright (c) 2002-2003, Jouni Malinen <jkmaline@cc.hut.fi>
 * Copyright (c) 2005, Devicescape Software, Inc.
 * Copyright (c) 2006, Michael Wu <flamingice@sourmilk.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.
 */

#ifndef IEEE80211_H
#define IEEE80211_H

#include <linux/types.h>
#include <asm/byteorder.h>

#define FCS_LEN 4

#define IEEE80211_FCTL_VERS		0x0003
#define IEEE80211_FCTL_FTYPE		0x000c
#define IEEE80211_FCTL_STYPE		0x00f0
#define IEEE80211_FCTL_TODS		0x0100
#define IEEE80211_FCTL_FROMDS		0x0200
#define IEEE80211_FCTL_MOREFRAGS	0x0400
#define IEEE80211_FCTL_RETRY		0x0800
#define IEEE80211_FCTL_PM		0x1000
#define IEEE80211_FCTL_MOREDATA		0x2000
#define IEEE80211_FCTL_PROTECTED	0x4000
#define IEEE80211_FCTL_ORDER		0x8000

#define IEEE80211_SCTL_FRAG		0x000F
#define IEEE80211_SCTL_SEQ		0xFFF0

#define IEEE80211_FTYPE_MGMT		0x0000
#define IEEE80211_FTYPE_CTL		0x0004
#define IEEE80211_FTYPE_DATA		0x0008

/* management */
#define IEEE80211_STYPE_ASSOC_REQ	0x0000
#define IEEE80211_STYPE_ASSOC_RESP	0x0010
#define IEEE80211_STYPE_REASSOC_REQ	0x0020
#define IEEE80211_STYPE_REASSOC_RESP	0x0030
#define IEEE80211_STYPE_PROBE_REQ	0x0040
#define IEEE80211_STYPE_PROBE_RESP	0x0050
#define IEEE80211_STYPE_BEACON		0x0080
#define IEEE80211_STYPE_ATIM		0x0090
#define IEEE80211_STYPE_DISASSOC	0x00A0
#define IEEE80211_STYPE_AUTH		0x00B0
#define IEEE80211_STYPE_DEAUTH		0x00C0
#define IEEE80211_STYPE_ACTION		0x00D0

/* control */
#define IEEE80211_STYPE_BACK_REQ	0x0080
#define IEEE80211_STYPE_BACK		0x0090
#define IEEE80211_STYPE_PSPOLL		0x00A0
#define IEEE80211_STYPE_RTS		0x00B0
#define IEEE80211_STYPE_CTS		0x00C0
#define IEEE80211_STYPE_ACK		0x00D0
#define IEEE80211_STYPE_CFEND		0x00E0
#define IEEE80211_STYPE_CFENDACK	0x00F0

/* data */
#define IEEE80211_STYPE_DATA			0x0000
#define IEEE80211_STYPE_DATA_CFACK		0x0010
#define IEEE80211_STYPE_DATA_CFPOLL		0x0020
#define IEEE80211_STYPE_DATA_CFACKPOLL		0x0030
#define IEEE80211_STYPE_NULLFUNC		0x0040
#define IEEE80211_STYPE_CFACK			0x0050
#define IEEE80211_STYPE_CFPOLL			0x0060
#define IEEE80211_STYPE_CFACKPOLL		0x0070
#define IEEE80211_STYPE_QOS_DATA		0x0080
#define IEEE80211_STYPE_QOS_DATA_CFACK		0x0090
#define IEEE80211_STYPE_QOS_DATA_CFPOLL		0x00A0
#define IEEE80211_STYPE_QOS_DATA_CFACKPOLL	0x00B0
#define IEEE80211_STYPE_QOS_NULLFUNC		0x00C0
#define IEEE80211_STYPE_QOS_CFACK		0x00D0
#define IEEE80211_STYPE_QOS_CFPOLL		0x00E0
#define IEEE80211_STYPE_QOS_CFACKPOLL		0x00F0


/* miscellaneous IEEE 802.11 constants */
#define IEEE80211_MAX_FRAG_THRESHOLD	2352
#define IEEE80211_MAX_RTS_THRESHOLD	2353
#define IEEE80211_MAX_AID		2007
#define IEEE80211_MAX_TIM_LEN		251
/* Maximum size for the MA-UNITDATA primitive, 802.11 standard section
   6.2.1.1.2.

   802.11e clarifies the figure in section 7.1.2. The frame body is
   up to 2304 octets long (maximum MSDU size) plus any crypt overhead. */
#define IEEE80211_MAX_DATA_LEN		2304
/* 30 byte 4 addr hdr, 2 byte QoS, 2304 byte MSDU, 12 byte crypt, 4 byte FCS */
#define IEEE80211_MAX_FRAME_LEN		2352

#define IEEE80211_MAX_SSID_LEN		32
#define IEEE80211_MAX_MESH_ID_LEN	32

struct ieee80211_hdr {
	__le16 frame_control;
	__le16 duration_id;
	u8 addr1[6];
	u8 addr2[6];
	u8 addr3[6];
	__le16 seq_ctrl;
	u8 addr4[6];
} __attribute__ ((packed));


struct ieee80211s_hdr {
	u8 flags;
	u8 ttl;
	__le32 seqnum;
	u8 eaddr1[6];
	u8 eaddr2[6];
	u8 eaddr3[6];
} __attribute__ ((packed));


struct ieee80211_mgmt {
	__le16 frame_control;
	__le16 duration;
	u8 da[6];
	u8 sa[6];
	u8 bssid[6];
	__le16 seq_ctrl;
	union {
		struct {
			__le16 auth_alg;
			__le16 auth_transaction;
			__le16 status_code;
			/* possibly followed by Challenge text */
			u8 variable[0];
		} __attribute__ ((packed)) auth;
		struct {
			__le16 reason_code;
		} __attribute__ ((packed)) deauth;
		struct {
			__le16 capab_info;
			__le16 listen_interval;
			/* followed by SSID and Supported rates */
			u8 variable[0];
		} __attribute__ ((packed)) assoc_req;
		struct {
			__le16 capab_info;
			__le16 status_code;
			__le16 aid;
			/* followed by Supported rates */
			u8 variable[0];
		} __attribute__ ((packed)) assoc_resp, reassoc_resp;
		struct {
			__le16 capab_info;
			__le16 listen_interval;
			u8 current_ap[6];
			/* followed by SSID and Supported rates */
			u8 variable[0];
		} __attribute__ ((packed)) reassoc_req;
		struct {
			__le16 reason_code;
		} __attribute__ ((packed)) disassoc;
		struct {
			__le64 timestamp;
			__le16 beacon_int;
			__le16 capab_info;
			/* followed by some of SSID, Supported rates,
			 * FH Params, DS Params, CF Params, IBSS Params, TIM */
			u8 variable[0];
		} __attribute__ ((packed)) beacon;
		struct {
			/* only variable items: SSID, Supported rates */
			u8 variable[0];
		} __attribute__ ((packed)) probe_req;
		struct {
			__le64 timestamp;
			__le16 beacon_int;
			__le16 capab_info;
			/* followed by some of SSID, Supported rates,
			 * FH Params, DS Params, CF Params, IBSS Params */
			u8 variable[0];
		} __attribute__ ((packed)) probe_resp;
		struct {
			u8 category;
			union {
				struct {
					u8 action_code;
					u8 dialog_token;
					u8 status_code;
					u8 variable[0];
				} __attribute__ ((packed)) wme_action;
				struct{
					u8 action_code;
					u8 element_id;
					u8 length;
					u8 switch_mode;
					u8 new_chan;
					u8 switch_count;
				} __attribute__((packed)) chan_switch;
				struct{
					u8 action_code;
					u8 dialog_token;
					__le16 capab;
					__le16 timeout;
					__le16 start_seq_num;
				} __attribute__((packed)) addba_req;
				struct{
					u8 action_code;
					u8 dialog_token;
					__le16 status;
					__le16 capab;
					__le16 timeout;
				} __attribute__((packed)) addba_resp;
				struct{
					u8 action_code;
					__le16 params;
					__le16 reason_code;
				} __attribute__((packed)) delba;
				struct{
					u8 action_code;
					/* capab_info for open and confirm,
					 * reason for close
					 */
					__le16 aux;
					/* Followed in plink_confirm by status
					 * code, AID and supported rates,
					 * and directly by supported rates in
					 * plink_open and plink_close
					 */
					u8 variable[0];
				} __attribute__((packed)) plink_action;
				struct{
					u8 action_code;
					u8 variable[0];
				} __attribute__((packed)) mesh_action;
			} u;
		} __attribute__ ((packed)) action;
	} u;
} __attribute__ ((packed));


/* Control frames */
struct ieee80211_rts {
	__le16 frame_control;
	__le16 duration;
	u8 ra[6];
	u8 ta[6];
} __attribute__ ((packed));

struct ieee80211_cts {
	__le16 frame_control;
	__le16 duration;
	u8 ra[6];
} __attribute__ ((packed));

/**
 * struct ieee80211_bar - HT Block Ack Request
 *
 * This structure refers to "HT BlockAckReq" as
 * described in 802.11n draft section 7.2.1.7.1
 */
struct ieee80211_bar {
	__le16 frame_control;
	__le16 duration;
	__u8 ra[6];
	__u8 ta[6];
	__le16 control;
	__le16 start_seq_num;
} __attribute__((packed));

/**
 * struct ieee80211_ht_cap - HT capabilities
 *
 * This structure refers to "HT capabilities element" as
 * described in 802.11n draft section 7.3.2.52
 */
struct ieee80211_ht_cap {
	__le16 cap_info;
	u8 ampdu_params_info;
	u8 supp_mcs_set[16];
	__le16 extended_ht_cap_info;
	__le32 tx_BF_cap_info;
	u8 antenna_selection_info;
} __attribute__ ((packed));

/**
 * struct ieee80211_ht_cap - HT additional information
 *
 * This structure refers to "HT information element" as
 * described in 802.11n draft section 7.3.2.53
 */
struct ieee80211_ht_addt_info {
	u8 control_chan;
	u8 ht_param;
	__le16 operation_mode;
	__le16 stbc_param;
	u8 basic_set[16];
} __attribute__ ((packed));

/* 802.11n HT capabilities masks */
#define IEEE80211_HT_CAP_SUP_WIDTH		0x0002
#define IEEE80211_HT_CAP_MIMO_PS		0x000C
#define IEEE80211_HT_CAP_GRN_FLD		0x0010
#define IEEE80211_HT_CAP_SGI_20			0x0020
#define IEEE80211_HT_CAP_SGI_40			0x0040
#define IEEE80211_HT_CAP_DELAY_BA		0x0400
#define IEEE80211_HT_CAP_MAX_AMSDU		0x0800
/* 802.11n HT capability AMPDU settings */
#define IEEE80211_HT_CAP_AMPDU_FACTOR		0x03
#define IEEE80211_HT_CAP_AMPDU_DENSITY		0x1C
/* 802.11n HT capability MSC set */
#define IEEE80211_SUPP_MCS_SET_UEQM		4
#define IEEE80211_HT_CAP_MAX_STREAMS		4
#define IEEE80211_SUPP_MCS_SET_LEN		10
/* maximum streams the spec allows */
#define IEEE80211_HT_CAP_MCS_TX_DEFINED		0x01
#define IEEE80211_HT_CAP_MCS_TX_RX_DIFF		0x02
#define IEEE80211_HT_CAP_MCS_TX_STREAMS		0x0C
#define IEEE80211_HT_CAP_MCS_TX_UEQM		0x10
/* 802.11n HT IE masks */
#define IEEE80211_HT_IE_CHA_SEC_OFFSET		0x03
#define IEEE80211_HT_IE_CHA_SEC_NONE	 	0x00
#define IEEE80211_HT_IE_CHA_SEC_ABOVE 		0x01
#define IEEE80211_HT_IE_CHA_SEC_BELOW 		0x03
#define IEEE80211_HT_IE_CHA_WIDTH		0x04
#define IEEE80211_HT_IE_HT_PROTECTION		0x0003
#define IEEE80211_HT_IE_NON_GF_STA_PRSNT	0x0004
#define IEEE80211_HT_IE_NON_HT_STA_PRSNT	0x0010

/* MIMO Power Save Modes */
#define WLAN_HT_CAP_MIMO_PS_STATIC	0
#define WLAN_HT_CAP_MIMO_PS_DYNAMIC	1
#define WLAN_HT_CAP_MIMO_PS_INVALID	2
#define WLAN_HT_CAP_MIMO_PS_DISABLED	3

/* Authentication algorithms */
#define WLAN_AUTH_OPEN 0
#define WLAN_AUTH_SHARED_KEY 1
#define WLAN_AUTH_FAST_BSS_TRANSITION 2
#define WLAN_AUTH_LEAP 128

#define WLAN_AUTH_CHALLENGE_LEN 128

#define WLAN_CAPABILITY_ESS		(1<<0)
#define WLAN_CAPABILITY_IBSS		(1<<1)
#define WLAN_CAPABILITY_CF_POLLABLE	(1<<2)
#define WLAN_CAPABILITY_CF_POLL_REQUEST	(1<<3)
#define WLAN_CAPABILITY_PRIVACY		(1<<4)
#define WLAN_CAPABILITY_SHORT_PREAMBLE	(1<<5)
#define WLAN_CAPABILITY_PBCC		(1<<6)
#define WLAN_CAPABILITY_CHANNEL_AGILITY	(1<<7)
/* 802.11h */
#define WLAN_CAPABILITY_SPECTRUM_MGMT	(1<<8)
#define WLAN_CAPABILITY_QOS		(1<<9)
#define WLAN_CAPABILITY_SHORT_SLOT_TIME	(1<<10)
#define WLAN_CAPABILITY_DSSS_OFDM	(1<<13)

/* 802.11g ERP information element */
#define WLAN_ERP_NON_ERP_PRESENT (1<<0)
#define WLAN_ERP_USE_PROTECTION (1<<1)
#define WLAN_ERP_BARKER_PREAMBLE (1<<2)

/* WLAN_ERP_BARKER_PREAMBLE values */
enum {
	WLAN_ERP_PREAMBLE_SHORT = 0,
	WLAN_ERP_PREAMBLE_LONG = 1,
};

/* Status codes */
enum ieee80211_statuscode {
	WLAN_STATUS_SUCCESS = 0,
	WLAN_STATUS_UNSPECIFIED_FAILURE = 1,
	WLAN_STATUS_CAPS_UNSUPPORTED = 10,
	WLAN_STATUS_REASSOC_NO_ASSOC = 11,
	WLAN_STATUS_ASSOC_DENIED_UNSPEC = 12,
	WLAN_STATUS_NOT_SUPPORTED_AUTH_ALG = 13,
	WLAN_STATUS_UNKNOWN_AUTH_TRANSACTION = 14,
	WLAN_STATUS_CHALLENGE_FAIL = 15,
	WLAN_STATUS_AUTH_TIMEOUT = 16,
	WLAN_STATUS_AP_UNABLE_TO_HANDLE_NEW_STA = 17,
	WLAN_STATUS_ASSOC_DENIED_RATES = 18,
	/* 802.11b */
	WLAN_STATUS_ASSOC_DENIED_NOSHORTPREAMBLE = 19,
	WLAN_STATUS_ASSOC_DENIED_NOPBCC = 20,
	WLAN_STATUS_ASSOC_DENIED_NOAGILITY = 21,
	/* 802.11h */
	WLAN_STATUS_ASSOC_DENIED_NOSPECTRUM = 22,
	WLAN_STATUS_ASSOC_REJECTED_BAD_POWER = 23,
	WLAN_STATUS_ASSOC_REJECTED_BAD_SUPP_CHAN = 24,
	/* 802.11g */
	WLAN_STATUS_ASSOC_DENIED_NOSHORTTIME = 25,
	WLAN_STATUS_ASSOC_DENIED_NODSSSOFDM = 26,
	/* 802.11i */
	WLAN_STATUS_INVALID_IE = 40,
	WLAN_STATUS_INVALID_GROUP_CIPHER = 41,
	WLAN_STATUS_INVALID_PAIRWISE_CIPHER = 42,
	WLAN_STATUS_INVALID_AKMP = 43,
	WLAN_STATUS_UNSUPP_RSN_VERSION = 44,
	WLAN_STATUS_INVALID_RSN_IE_CAP = 45,
	WLAN_STATUS_CIPHER_SUITE_REJECTED = 46,
	/* 802.11e */
	WLAN_STATUS_UNSPECIFIED_QOS = 32,
	WLAN_STATUS_ASSOC_DENIED_NOBANDWIDTH = 33,
	WLAN_STATUS_ASSOC_DENIED_LOWACK = 34,
	WLAN_STATUS_ASSOC_DENIED_UNSUPP_QOS = 35,
	WLAN_STATUS_REQUEST_DECLINED = 37,
	WLAN_STATUS_INVALID_QOS_PARAM = 38,
	WLAN_STATUS_CHANGE_TSPEC = 39,
	WLAN_STATUS_WAIT_TS_DELAY = 47,
	WLAN_STATUS_NO_DIRECT_LINK = 48,
	WLAN_STATUS_STA_NOT_PRESENT = 49,
	WLAN_STATUS_STA_NOT_QSTA = 50,
};


/* Reason codes */
enum ieee80211_reasoncode {
	WLAN_REASON_UNSPECIFIED = 1,
	WLAN_REASON_PREV_AUTH_NOT_VALID = 2,
	WLAN_REASON_DEAUTH_LEAVING = 3,
	WLAN_REASON_DISASSOC_DUE_TO_INACTIVITY = 4,
	WLAN_REASON_DISASSOC_AP_BUSY = 5,
	WLAN_REASON_CLASS2_FRAME_FROM_NONAUTH_STA = 6,
	WLAN_REASON_CLASS3_FRAME_FROM_NONASSOC_STA = 7,
	WLAN_REASON_DISASSOC_STA_HAS_LEFT = 8,
	WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH = 9,
	/* 802.11h */
	WLAN_REASON_DISASSOC_BAD_POWER = 10,
	WLAN_REASON_DISASSOC_BAD_SUPP_CHAN = 11,
	/* 802.11i */
	WLAN_REASON_INVALID_IE = 13,
	WLAN_REASON_MIC_FAILURE = 14,
	WLAN_REASON_4WAY_HANDSHAKE_TIMEOUT = 15,
	WLAN_REASON_GROUP_KEY_HANDSHAKE_TIMEOUT = 16,
	WLAN_REASON_IE_DIFFERENT = 17,
	WLAN_REASON_INVALID_GROUP_CIPHER = 18,
	WLAN_REASON_INVALID_PAIRWISE_CIPHER = 19,
	WLAN_REASON_INVALID_AKMP = 20,
	WLAN_REASON_UNSUPP_RSN_VERSION = 21,
	WLAN_REASON_INVALID_RSN_IE_CAP = 22,
	WLAN_REASON_IEEE8021X_FAILED = 23,
	WLAN_REASON_CIPHER_SUITE_REJECTED = 24,
	/* 802.11e */
	WLAN_REASON_DISASSOC_UNSPECIFIED_QOS = 32,
	WLAN_REASON_DISASSOC_QAP_NO_BANDWIDTH = 33,
	WLAN_REASON_DISASSOC_LOW_ACK = 34,
	WLAN_REASON_DISASSOC_QAP_EXCEED_TXOP = 35,
	WLAN_REASON_QSTA_LEAVE_QBSS = 36,
	WLAN_REASON_QSTA_NOT_USE = 37,
	WLAN_REASON_QSTA_REQUIRE_SETUP = 38,
	WLAN_REASON_QSTA_TIMEOUT = 39,
	WLAN_REASON_QSTA_CIPHER_NOT_SUPP = 45,
};


/* Information Element IDs */
enum ieee80211_eid {
	WLAN_EID_SSID = 0,
	WLAN_EID_SUPP_RATES = 1,
	WLAN_EID_FH_PARAMS = 2,
	WLAN_EID_DS_PARAMS = 3,
	WLAN_EID_CF_PARAMS = 4,
	WLAN_EID_TIM = 5,
	WLAN_EID_IBSS_PARAMS = 6,
	WLAN_EID_CHALLENGE = 16,
	/* 802.11d */
	WLAN_EID_COUNTRY = 7,
	WLAN_EID_HP_PARAMS = 8,
	WLAN_EID_HP_TABLE = 9,
	WLAN_EID_REQUEST = 10,
	/* 802.11e */
	WLAN_EID_QBSS_LOAD = 11,
	WLAN_EID_EDCA_PARAM_SET = 12,
	WLAN_EID_TSPEC = 13,
	WLAN_EID_TCLAS = 14,
	WLAN_EID_SCHEDULE = 15,
	WLAN_EID_TS_DELAY = 43,
	WLAN_EID_TCLAS_PROCESSING = 44,
	WLAN_EID_QOS_CAPA = 46,
	/* 802.11s
	 *
	 * All mesh EID numbers are pending IEEE 802.11 ANA approval.
	 * The numbers have been incremented from those suggested in
	 * 802.11s/D2.0 so that MESH_CONFIG does not conflict with
	 * EXT_SUPP_RATES.
	 */
	WLAN_EID_MESH_CONFIG = 51,
	WLAN_EID_MESH_ID = 52,
	WLAN_EID_PEER_LINK = 55,
	WLAN_EID_PREQ = 68,
	WLAN_EID_PREP = 69,
	WLAN_EID_PERR = 70,
	/* 802.11h */
	WLAN_EID_PWR_CONSTRAINT = 32,
	WLAN_EID_PWR_CAPABILITY = 33,
	WLAN_EID_TPC_REQUEST = 34,
	WLAN_EID_TPC_REPORT = 35,
	WLAN_EID_SUPPORTED_CHANNELS = 36,
	WLAN_EID_CHANNEL_SWITCH = 37,
	WLAN_EID_MEASURE_REQUEST = 38,
	WLAN_EID_MEASURE_REPORT = 39,
	WLAN_EID_QUIET = 40,
	WLAN_EID_IBSS_DFS = 41,
	/* 802.11g */
	WLAN_EID_ERP_INFO = 42,
	WLAN_EID_EXT_SUPP_RATES = 50,
	/* 802.11n */
	WLAN_EID_HT_CAPABILITY = 45,
	WLAN_EID_HT_EXTRA_INFO = 61,
	/* 802.11i */
	WLAN_EID_RSN = 48,
	WLAN_EID_WPA = 221,
	WLAN_EID_GENERIC = 221,
	WLAN_EID_VENDOR_SPECIFIC = 221,
	WLAN_EID_QOS_PARAMETER = 222
};

/* Action category code */
enum ieee80211_category {
	WLAN_CATEGORY_SPECTRUM_MGMT = 0,
	WLAN_CATEGORY_QOS = 1,
	WLAN_CATEGORY_DLS = 2,
	WLAN_CATEGORY_BACK = 3,
	WLAN_CATEGORY_WMM = 17,
};

/* BACK action code */
enum ieee80211_back_actioncode {
	WLAN_ACTION_ADDBA_REQ = 0,
	WLAN_ACTION_ADDBA_RESP = 1,
	WLAN_ACTION_DELBA = 2,
};

/* BACK (block-ack) parties */
enum ieee80211_back_parties {
	WLAN_BACK_RECIPIENT = 0,
	WLAN_BACK_INITIATOR = 1,
	WLAN_BACK_TIMER = 2,
};

/* A-MSDU 802.11n */
#define IEEE80211_QOS_CONTROL_A_MSDU_PRESENT 0x0080

/* cipher suite selectors */
#define WLAN_CIPHER_SUITE_USE_GROUP	0x000FAC00
#define WLAN_CIPHER_SUITE_WEP40		0x000FAC01
#define WLAN_CIPHER_SUITE_TKIP		0x000FAC02
/* reserved: 				0x000FAC03 */
#define WLAN_CIPHER_SUITE_CCMP		0x000FAC04
#define WLAN_CIPHER_SUITE_WEP104	0x000FAC05

#define WLAN_MAX_KEY_LEN		32

/**
 * ieee80211_get_SA - get pointer to SA
 *
 * Given an 802.11 frame, this function returns the offset
 * to the source address (SA). It does not verify that the
 * header is long enough to contain the address, and the
 * header must be long enough to contain the frame control
 * field.
 *
 * @hdr: the frame
 */
static inline u8 *ieee80211_get_SA(struct ieee80211_hdr *hdr)
{
	__le16 fc = hdr->frame_control;
	fc &= cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);

	switch (fc) {
	case __constant_cpu_to_le16(IEEE80211_FCTL_FROMDS):
		return hdr->addr3;
	case __constant_cpu_to_le16(IEEE80211_FCTL_TODS|IEEE80211_FCTL_FROMDS):
		return hdr->addr4;
	default:
		return hdr->addr2;
	}
}

/**
 * ieee80211_get_DA - get pointer to DA
 *
 * Given an 802.11 frame, this function returns the offset
 * to the destination address (DA). It does not verify that
 * the header is long enough to contain the address, and the
 * header must be long enough to contain the frame control
 * field.
 *
 * @hdr: the frame
 */
static inline u8 *ieee80211_get_DA(struct ieee80211_hdr *hdr)
{
	__le16 fc = hdr->frame_control;
	fc &= cpu_to_le16(IEEE80211_FCTL_TODS);

	if (fc)
		return hdr->addr3;
	else
		return hdr->addr1;
}

/**
 * ieee80211_get_morefrag - determine whether the MOREFRAGS bit is set
 *
 * This function determines whether the "more fragments" bit is set
 * in the frame.
 *
 * @hdr: the frame
 */
static inline int ieee80211_get_morefrag(struct ieee80211_hdr *hdr)
{
	__le16 fc = hdr->frame_control;
	return !!(fc & cpu_to_le16(IEEE80211_FCTL_MOREFRAGS));
}

#endif /* IEEE80211_H */