include/linux/usb/wusb.h - kernel/windcharger - Git at Google

 /*
  * Wireless USB Standard Definitions
  * Event Size Tables
  *
  * Copyright (C) 2005-2006 Intel Corporation
  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
  *
  * 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.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  * 02110-1301, USA.
  *
  *
  * FIXME: docs
  * FIXME: organize properly, group logically
  *
  * All the event structures are defined in uwb/spec.h, as they are
  * common to the WHCI and WUSB radio control interfaces.
  */

 #ifndef __WUSB_H__
 #define __WUSB_H__

 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/uwb/spec.h>
 #include <linux/usb/ch9.h>
 #include <linux/param.h>

 /**
  * WUSB Information Element header
  *
  * I don't know why, they decided to make it different to the MBOA MAC
  * IE Header; beats me.
  */
 struct wuie_hdr {
 	u8 bLength;
 	u8 bIEIdentifier;
 } __attribute__((packed));

 enum {
 	WUIE_ID_WCTA = 0x80,
 	WUIE_ID_CONNECTACK,
 	WUIE_ID_HOST_INFO,
 	WUIE_ID_CHANGE_ANNOUNCE,
 	WUIE_ID_DEVICE_DISCONNECT,
 	WUIE_ID_HOST_DISCONNECT,
 	WUIE_ID_KEEP_ALIVE = 0x89,
 	WUIE_ID_ISOCH_DISCARD,
 	WUIE_ID_RESET_DEVICE,
 };

 /**
  * Maximum number of array elements in a WUSB IE.
  *
  * WUSB1.0[7.5 before table 7-38] says that in WUSB IEs that
  * are "arrays" have to limited to 4 elements. So we define it
  * like that to ease up and submit only the neeed size.
  */
 #define WUIE_ELT_MAX 4

 /**
  * Wrapper for the data that defines a CHID, a CDID or a CK
  *
  * WUSB defines that CHIDs, CDIDs and CKs are a 16 byte string of
  * data. In order to avoid confusion and enforce types, we wrap it.
  *
  * Make it packed, as we use it in some hw definitions.
  */
 struct wusb_ckhdid {
 	u8 data[16];
 } __attribute__((packed));

 static const struct wusb_ckhdid wusb_ckhdid_zero = { .data = { 0 } };

 #define WUSB_CKHDID_STRSIZE (3 * sizeof(struct wusb_ckhdid) + 1)

 /**
  * WUSB IE: Host Information (WUSB1.0[7.5.2])
  *
  * Used to provide information about the host to the Wireless USB
  * devices in range (CHID can be used as an ASCII string).
  */
 struct wuie_host_info {
 	struct wuie_hdr hdr;
 	__le16 attributes;
 	struct wusb_ckhdid CHID;
 } __attribute__((packed));

 /**
  * WUSB IE: Connect Ack (WUSB1.0[7.5.1])
  *
  * Used to acknowledge device connect requests. See note for
  * WUIE_ELT_MAX.
  */
 struct wuie_connect_ack {
 	struct wuie_hdr hdr;
 	struct {
 		struct wusb_ckhdid CDID;
 		u8 bDeviceAddress;	/* 0 means unused */
 		u8 bReserved;
 	} blk[WUIE_ELT_MAX];
 } __attribute__((packed));

 /**
  * WUSB IE Host Information Element, Connect Availability
  *
  * WUSB1.0[7.5.2], bmAttributes description
  */
 enum {
 	WUIE_HI_CAP_RECONNECT = 0,
 	WUIE_HI_CAP_LIMITED,
 	WUIE_HI_CAP_RESERVED,
 	WUIE_HI_CAP_ALL,
 };

 /**
  * WUSB IE: Channel Stop (WUSB1.0[7.5.8])
  *
  * Tells devices the host is going to stop sending MMCs and will disappear.
  */
 struct wuie_channel_stop {
 	struct wuie_hdr hdr;
 	u8 attributes;
 	u8 timestamp[3];
 } __attribute__((packed));

 /**
  * WUSB IE: Keepalive (WUSB1.0[7.5.9])
  *
  * Ask device(s) to send keepalives.
  */
 struct wuie_keep_alive {
 	struct wuie_hdr hdr;
 	u8 bDeviceAddress[WUIE_ELT_MAX];
 } __attribute__((packed));

 /**
  * WUSB IE: Reset device (WUSB1.0[7.5.11])
  *
  * Tell device to reset; in all truth, we can fit 4 CDIDs, but we only
  * use it for one at the time...
  *
  * In any case, this request is a wee bit silly: why don't they target
  * by address??
  */
 struct wuie_reset {
 	struct wuie_hdr hdr;
 	struct wusb_ckhdid CDID;
 } __attribute__((packed));

 /**
  * WUSB IE: Disconnect device (WUSB1.0[7.5.11])
  *
  * Tell device to disconnect; we can fit 4 addresses, but we only use
  * it for one at the time...
  */
 struct wuie_disconnect {
 	struct wuie_hdr hdr;
 	u8 bDeviceAddress;
 	u8 padding;
 } __attribute__((packed));

 /**
  * WUSB IE: Host disconnect ([WUSB] section 7.5.5)
  *
  * Tells all connected devices to disconnect.
  */
 struct wuie_host_disconnect {
 	struct wuie_hdr hdr;
 } __attribute__((packed));

 /**
  * WUSB Device Notification header (WUSB1.0[7.6])
  */
 struct wusb_dn_hdr {
 	u8 bType;
 	u8 notifdata[];
 } __attribute__((packed));

 /** Device Notification codes (WUSB1.0[Table 7-54]) */
 enum WUSB_DN {
 	WUSB_DN_CONNECT = 0x01,
 	WUSB_DN_DISCONNECT = 0x02,
 	WUSB_DN_EPRDY = 0x03,
 	WUSB_DN_MASAVAILCHANGED = 0x04,
 	WUSB_DN_RWAKE = 0x05,
 	WUSB_DN_SLEEP = 0x06,
 	WUSB_DN_ALIVE = 0x07,
 };

 /** WUSB Device Notification Connect */
 struct wusb_dn_connect {
 	struct wusb_dn_hdr hdr;
 	__le16 attributes;
 	struct wusb_ckhdid CDID;
 } __attribute__((packed));

 static inline int wusb_dn_connect_prev_dev_addr(const struct wusb_dn_connect *dn)
 {
 	return le16_to_cpu(dn->attributes) & 0xff;
 }

 static inline int wusb_dn_connect_new_connection(const struct wusb_dn_connect *dn)
 {
 	return (le16_to_cpu(dn->attributes) >> 8) & 0x1;
 }

 static inline int wusb_dn_connect_beacon_behavior(const struct wusb_dn_connect *dn)
 {
 	return (le16_to_cpu(dn->attributes) >> 9) & 0x03;
 }

 /** Device is alive (aka: pong) (WUSB1.0[7.6.7]) */
 struct wusb_dn_alive {
 	struct wusb_dn_hdr hdr;
 } __attribute__((packed));

 /** Device is disconnecting (WUSB1.0[7.6.2]) */
 struct wusb_dn_disconnect {
 	struct wusb_dn_hdr hdr;
 } __attribute__((packed));

 /* General constants */
 enum {
 	WUSB_TRUST_TIMEOUT_MS = 4000,	/* [WUSB] section 4.15.1 */
 };

 static inline size_t ckhdid_printf(char *pr_ckhdid, size_t size,
 				   const struct wusb_ckhdid *ckhdid)
 {
 	return scnprintf(pr_ckhdid, size,
 			 "%02hx %02hx %02hx %02hx %02hx %02hx %02hx %02hx "
 			 "%02hx %02hx %02hx %02hx %02hx %02hx %02hx %02hx",
 			 ckhdid->data[0],  ckhdid->data[1],
 			 ckhdid->data[2],  ckhdid->data[3],
 			 ckhdid->data[4],  ckhdid->data[5],
 			 ckhdid->data[6],  ckhdid->data[7],
 			 ckhdid->data[8],  ckhdid->data[9],
 			 ckhdid->data[10], ckhdid->data[11],
 			 ckhdid->data[12], ckhdid->data[13],
 			 ckhdid->data[14], ckhdid->data[15]);
 }

 /*
  * WUSB Crypto stuff (WUSB1.0[6])
  */

 extern const char *wusb_et_name(u8);

 /**
  * WUSB key index WUSB1.0[7.3.2.4], for usage when setting keys for
  * the host or the device.
  */
 static inline u8 wusb_key_index(int index, int type, int originator)
 {
 	return (originator << 6) | (type << 4) | index;
 }

 #define WUSB_KEY_INDEX_TYPE_PTK			0 /* for HWA only */
 #define WUSB_KEY_INDEX_TYPE_ASSOC		1
 #define WUSB_KEY_INDEX_TYPE_GTK			2
 #define WUSB_KEY_INDEX_ORIGINATOR_HOST		0
 #define WUSB_KEY_INDEX_ORIGINATOR_DEVICE	1

 /* A CCM Nonce, defined in WUSB1.0[6.4.1] */
 struct aes_ccm_nonce {
 	u8 sfn[6];              /* Little Endian */
 	u8 tkid[3];             /* LE */
 	struct uwb_dev_addr dest_addr;
 	struct uwb_dev_addr src_addr;
 } __attribute__((packed));

 /* A CCM operation label, defined on WUSB1.0[6.5.x] */
 struct aes_ccm_label {
 	u8 data[14];
 } __attribute__((packed));

 /*
  * Input to the key derivation sequence defined in
  * WUSB1.0[6.5.1]. Rest of the data is in the CCM Nonce passed to the
  * PRF function.
  */
 struct wusb_keydvt_in {
 	u8 hnonce[16];
 	u8 dnonce[16];
 } __attribute__((packed));

 /*
  * Output from the key derivation sequence defined in
  * WUSB1.0[6.5.1].
  */
 struct wusb_keydvt_out {
 	u8 kck[16];
 	u8 ptk[16];
 } __attribute__((packed));

 /* Pseudo Random Function WUSB1.0[6.5] */
 extern int wusb_crypto_init(void);
 extern void wusb_crypto_exit(void);
 extern ssize_t wusb_prf(void *out, size_t out_size,
 			const u8 key[16], const struct aes_ccm_nonce *_n,
 			const struct aes_ccm_label *a,
 			const void *b, size_t blen, size_t len);

 static inline int wusb_prf_64(void *out, size_t out_size, const u8 key[16],
 			      const struct aes_ccm_nonce *n,
 			      const struct aes_ccm_label *a,
 			      const void *b, size_t blen)
 {
 	return wusb_prf(out, out_size, key, n, a, b, blen, 64);
 }

 static inline int wusb_prf_128(void *out, size_t out_size, const u8 key[16],
 			       const struct aes_ccm_nonce *n,
 			       const struct aes_ccm_label *a,
 			       const void *b, size_t blen)
 {
 	return wusb_prf(out, out_size, key, n, a, b, blen, 128);
 }

 static inline int wusb_prf_256(void *out, size_t out_size, const u8 key[16],
 			       const struct aes_ccm_nonce *n,
 			       const struct aes_ccm_label *a,
 			       const void *b, size_t blen)
 {
 	return wusb_prf(out, out_size, key, n, a, b, blen, 256);
 }

 /* Key derivation WUSB1.0[6.5.1] */
 static inline int wusb_key_derive(struct wusb_keydvt_out *keydvt_out,
 				  const u8 key[16],
 				  const struct aes_ccm_nonce *n,
 				  const struct wusb_keydvt_in *keydvt_in)
 {
 	const struct aes_ccm_label a = { .data = "Pair-wise keys" };
 	return wusb_prf_256(keydvt_out, sizeof(*keydvt_out), key, n, &a,
 			    keydvt_in, sizeof(*keydvt_in));
 }

 /*
  * Out-of-band MIC Generation WUSB1.0[6.5.2]
  *
  * Compute the MIC over @key, @n and @hs and place it in @mic_out.
  *
  * @mic_out:  Where to place the 8 byte MIC tag
  * @key:      KCK from the derivation process
  * @n:        CCM nonce, n->sfn == 0, TKID as established in the
  *            process.
  * @hs:       Handshake struct for phase 2 of the 4-way.
  *            hs->bStatus and hs->bReserved are zero.
  *            hs->bMessageNumber is 2 (WUSB1.0[7.3.2.5.2]
  *            hs->dest_addr is the device's USB address padded with 0
  *            hs->src_addr is the hosts's UWB device address
  *            hs->mic is ignored (as we compute that value).
  */
 static inline int wusb_oob_mic(u8 mic_out[8], const u8 key[16],
 			       const struct aes_ccm_nonce *n,
 			       const struct usb_handshake *hs)
 {
 	const struct aes_ccm_label a = { .data = "out-of-bandMIC" };
 	return wusb_prf_64(mic_out, 8, key, n, &a,
 			   hs, sizeof(*hs) - sizeof(hs->MIC));
 }

 #endif /* #ifndef __WUSB_H__ */
	/*
	* Wireless USB Standard Definitions
	* Event Size Tables
	*
	* Copyright (C) 2005-2006 Intel Corporation
	* Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
	*
	* 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.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
	* 02110-1301, USA.
	*
	*
	* FIXME: docs
	* FIXME: organize properly, group logically
	*
	* All the event structures are defined in uwb/spec.h, as they are
	* common to the WHCI and WUSB radio control interfaces.
	*/

	#ifndef __WUSB_H__
	#define __WUSB_H__

	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/uwb/spec.h>
	#include <linux/usb/ch9.h>
	#include <linux/param.h>

	/**
	* WUSB Information Element header
	*
	* I don't know why, they decided to make it different to the MBOA MAC
	* IE Header; beats me.
	*/
	struct wuie_hdr {
	u8 bLength;
	u8 bIEIdentifier;
	} __attribute__((packed));

	enum {
	WUIE_ID_WCTA = 0x80,
	WUIE_ID_CONNECTACK,
	WUIE_ID_HOST_INFO,
	WUIE_ID_CHANGE_ANNOUNCE,
	WUIE_ID_DEVICE_DISCONNECT,
	WUIE_ID_HOST_DISCONNECT,
	WUIE_ID_KEEP_ALIVE = 0x89,
	WUIE_ID_ISOCH_DISCARD,
	WUIE_ID_RESET_DEVICE,
	};

	/**
	* Maximum number of array elements in a WUSB IE.
	*
	* WUSB1.0[7.5 before table 7-38] says that in WUSB IEs that
	* are "arrays" have to limited to 4 elements. So we define it
	* like that to ease up and submit only the neeed size.
	*/
	#define WUIE_ELT_MAX 4

	/**
	* Wrapper for the data that defines a CHID, a CDID or a CK
	*
	* WUSB defines that CHIDs, CDIDs and CKs are a 16 byte string of
	* data. In order to avoid confusion and enforce types, we wrap it.
	*
	* Make it packed, as we use it in some hw definitions.
	*/
	struct wusb_ckhdid {
	u8 data[16];
	} __attribute__((packed));

	static const struct wusb_ckhdid wusb_ckhdid_zero = { .data = { 0 } };

	#define WUSB_CKHDID_STRSIZE (3 * sizeof(struct wusb_ckhdid) + 1)

	/**
	* WUSB IE: Host Information (WUSB1.0[7.5.2])
	*
	* Used to provide information about the host to the Wireless USB
	* devices in range (CHID can be used as an ASCII string).
	*/
	struct wuie_host_info {
	struct wuie_hdr hdr;
	__le16 attributes;
	struct wusb_ckhdid CHID;
	} __attribute__((packed));

	/**
	* WUSB IE: Connect Ack (WUSB1.0[7.5.1])
	*
	* Used to acknowledge device connect requests. See note for
	* WUIE_ELT_MAX.
	*/
	struct wuie_connect_ack {
	struct wuie_hdr hdr;
	struct {
	struct wusb_ckhdid CDID;
	u8 bDeviceAddress; /* 0 means unused */
	u8 bReserved;
	} blk[WUIE_ELT_MAX];
	} __attribute__((packed));

	/**
	* WUSB IE Host Information Element, Connect Availability
	*
	* WUSB1.0[7.5.2], bmAttributes description
	*/
	enum {
	WUIE_HI_CAP_RECONNECT = 0,
	WUIE_HI_CAP_LIMITED,
	WUIE_HI_CAP_RESERVED,
	WUIE_HI_CAP_ALL,
	};

	/**
	* WUSB IE: Channel Stop (WUSB1.0[7.5.8])
	*
	* Tells devices the host is going to stop sending MMCs and will disappear.
	*/
	struct wuie_channel_stop {
	struct wuie_hdr hdr;
	u8 attributes;
	u8 timestamp[3];
	} __attribute__((packed));

	/**
	* WUSB IE: Keepalive (WUSB1.0[7.5.9])
	*
	* Ask device(s) to send keepalives.
	*/
	struct wuie_keep_alive {
	struct wuie_hdr hdr;
	u8 bDeviceAddress[WUIE_ELT_MAX];
	} __attribute__((packed));

	/**
	* WUSB IE: Reset device (WUSB1.0[7.5.11])
	*
	* Tell device to reset; in all truth, we can fit 4 CDIDs, but we only
	* use it for one at the time...
	*
	* In any case, this request is a wee bit silly: why don't they target
	* by address??
	*/
	struct wuie_reset {
	struct wuie_hdr hdr;
	struct wusb_ckhdid CDID;
	} __attribute__((packed));

	/**
	* WUSB IE: Disconnect device (WUSB1.0[7.5.11])
	*
	* Tell device to disconnect; we can fit 4 addresses, but we only use
	* it for one at the time...
	*/
	struct wuie_disconnect {
	struct wuie_hdr hdr;
	u8 bDeviceAddress;
	u8 padding;
	} __attribute__((packed));

	/**
	* WUSB IE: Host disconnect ([WUSB] section 7.5.5)
	*
	* Tells all connected devices to disconnect.
	*/
	struct wuie_host_disconnect {
	struct wuie_hdr hdr;
	} __attribute__((packed));

	/**
	* WUSB Device Notification header (WUSB1.0[7.6])
	*/
	struct wusb_dn_hdr {
	u8 bType;
	u8 notifdata[];
	} __attribute__((packed));

	/** Device Notification codes (WUSB1.0[Table 7-54]) */
	enum WUSB_DN {
	WUSB_DN_CONNECT = 0x01,
	WUSB_DN_DISCONNECT = 0x02,
	WUSB_DN_EPRDY = 0x03,
	WUSB_DN_MASAVAILCHANGED = 0x04,
	WUSB_DN_RWAKE = 0x05,
	WUSB_DN_SLEEP = 0x06,
	WUSB_DN_ALIVE = 0x07,
	};

	/** WUSB Device Notification Connect */
	struct wusb_dn_connect {
	struct wusb_dn_hdr hdr;
	__le16 attributes;
	struct wusb_ckhdid CDID;
	} __attribute__((packed));

	static inline int wusb_dn_connect_prev_dev_addr(const struct wusb_dn_connect *dn)
	{
	return le16_to_cpu(dn->attributes) & 0xff;
	}

	static inline int wusb_dn_connect_new_connection(const struct wusb_dn_connect *dn)
	{
	return (le16_to_cpu(dn->attributes) >> 8) & 0x1;
	}

	static inline int wusb_dn_connect_beacon_behavior(const struct wusb_dn_connect *dn)
	{
	return (le16_to_cpu(dn->attributes) >> 9) & 0x03;
	}

	/** Device is alive (aka: pong) (WUSB1.0[7.6.7]) */
	struct wusb_dn_alive {
	struct wusb_dn_hdr hdr;
	} __attribute__((packed));

	/** Device is disconnecting (WUSB1.0[7.6.2]) */
	struct wusb_dn_disconnect {
	struct wusb_dn_hdr hdr;
	} __attribute__((packed));

	/* General constants */
	enum {
	WUSB_TRUST_TIMEOUT_MS = 4000, /* [WUSB] section 4.15.1 */
	};

	static inline size_t ckhdid_printf(char *pr_ckhdid, size_t size,
	const struct wusb_ckhdid *ckhdid)
	{
	return scnprintf(pr_ckhdid, size,
	"%02hx %02hx %02hx %02hx %02hx %02hx %02hx %02hx "
	"%02hx %02hx %02hx %02hx %02hx %02hx %02hx %02hx",
	ckhdid->data[0], ckhdid->data[1],
	ckhdid->data[2], ckhdid->data[3],
	ckhdid->data[4], ckhdid->data[5],
	ckhdid->data[6], ckhdid->data[7],
	ckhdid->data[8], ckhdid->data[9],
	ckhdid->data[10], ckhdid->data[11],
	ckhdid->data[12], ckhdid->data[13],
	ckhdid->data[14], ckhdid->data[15]);
	}

	/*
	* WUSB Crypto stuff (WUSB1.0[6])
	*/

	extern const char *wusb_et_name(u8);

	/**
	* WUSB key index WUSB1.0[7.3.2.4], for usage when setting keys for
	* the host or the device.
	*/
	static inline u8 wusb_key_index(int index, int type, int originator)
	{
	return (originator << 6) \| (type << 4) \| index;
	}

	#define WUSB_KEY_INDEX_TYPE_PTK 0 /* for HWA only */
	#define WUSB_KEY_INDEX_TYPE_ASSOC 1
	#define WUSB_KEY_INDEX_TYPE_GTK 2
	#define WUSB_KEY_INDEX_ORIGINATOR_HOST 0
	#define WUSB_KEY_INDEX_ORIGINATOR_DEVICE 1

	/* A CCM Nonce, defined in WUSB1.0[6.4.1] */
	struct aes_ccm_nonce {
	u8 sfn[6]; /* Little Endian */
	u8 tkid[3]; /* LE */
	struct uwb_dev_addr dest_addr;
	struct uwb_dev_addr src_addr;
	} __attribute__((packed));

	/* A CCM operation label, defined on WUSB1.0[6.5.x] */
	struct aes_ccm_label {
	u8 data[14];
	} __attribute__((packed));

	/*
	* Input to the key derivation sequence defined in
	* WUSB1.0[6.5.1]. Rest of the data is in the CCM Nonce passed to the
	* PRF function.
	*/
	struct wusb_keydvt_in {
	u8 hnonce[16];
	u8 dnonce[16];
	} __attribute__((packed));

	/*
	* Output from the key derivation sequence defined in
	* WUSB1.0[6.5.1].
	*/
	struct wusb_keydvt_out {
	u8 kck[16];
	u8 ptk[16];
	} __attribute__((packed));

	/* Pseudo Random Function WUSB1.0[6.5] */
	extern int wusb_crypto_init(void);
	extern void wusb_crypto_exit(void);
	extern ssize_t wusb_prf(void *out, size_t out_size,
	const u8 key[16], const struct aes_ccm_nonce *_n,
	const struct aes_ccm_label *a,
	const void *b, size_t blen, size_t len);

	static inline int wusb_prf_64(void *out, size_t out_size, const u8 key[16],
	const struct aes_ccm_nonce *n,
	const struct aes_ccm_label *a,
	const void *b, size_t blen)
	{
	return wusb_prf(out, out_size, key, n, a, b, blen, 64);
	}

	static inline int wusb_prf_128(void *out, size_t out_size, const u8 key[16],
	const struct aes_ccm_nonce *n,
	const struct aes_ccm_label *a,
	const void *b, size_t blen)
	{
	return wusb_prf(out, out_size, key, n, a, b, blen, 128);
	}

	static inline int wusb_prf_256(void *out, size_t out_size, const u8 key[16],
	const struct aes_ccm_nonce *n,
	const struct aes_ccm_label *a,
	const void *b, size_t blen)
	{
	return wusb_prf(out, out_size, key, n, a, b, blen, 256);
	}

	/* Key derivation WUSB1.0[6.5.1] */
	static inline int wusb_key_derive(struct wusb_keydvt_out *keydvt_out,
	const u8 key[16],
	const struct aes_ccm_nonce *n,
	const struct wusb_keydvt_in *keydvt_in)
	{
	const struct aes_ccm_label a = { .data = "Pair-wise keys" };
	return wusb_prf_256(keydvt_out, sizeof(*keydvt_out), key, n, &a,
	keydvt_in, sizeof(*keydvt_in));
	}

	/*
	* Out-of-band MIC Generation WUSB1.0[6.5.2]
	*
	* Compute the MIC over @key, @n and @hs and place it in @mic_out.
	*
	* @mic_out: Where to place the 8 byte MIC tag
	* @key: KCK from the derivation process
	* @n: CCM nonce, n->sfn == 0, TKID as established in the
	* process.
	* @hs: Handshake struct for phase 2 of the 4-way.
	* hs->bStatus and hs->bReserved are zero.
	* hs->bMessageNumber is 2 (WUSB1.0[7.3.2.5.2]
	* hs->dest_addr is the device's USB address padded with 0
	* hs->src_addr is the hosts's UWB device address
	* hs->mic is ignored (as we compute that value).
	*/
	static inline int wusb_oob_mic(u8 mic_out[8], const u8 key[16],
	const struct aes_ccm_nonce *n,
	const struct usb_handshake *hs)
	{
	const struct aes_ccm_label a = { .data = "out-of-bandMIC" };
	return wusb_prf_64(mic_out, 8, key, n, &a,
	hs, sizeof(*hs) - sizeof(hs->MIC));
	}

	#endif /* #ifndef __WUSB_H__ */