mac/ie.c - kernel/google-modules/uwb - Git at Google

 /*
  * This file is part of the UWB stack for linux.
  *
  * Copyright (c) 2020-2021 Qorvo US, Inc.
  *
  * This software is provided under the GNU General Public License, version 2
  * (GPLv2), as well as under a Qorvo commercial license.
  *
  * You may choose to use this software under the terms of the GPLv2 License,
  * version 2 ("GPLv2"), as published by the Free Software Foundation.
  * You should have received a copy of the GPLv2 along with this program.  If
  * not, see <http://www.gnu.org/licenses/>.
  *
  * This program is distributed under the GPLv2 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 GPLv2 for more
  * details.
  *
  * If you cannot meet the requirements of the GPLv2, you may not use this
  * software for any purpose without first obtaining a commercial license from
  * Qorvo. Please contact Qorvo to inquire about licensing terms.
  */

 #include <asm/unaligned.h>
 #include <linux/bitfield.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/ieee802154.h>
 #include <linux/module.h>
 #include <net/mcps802154_frame.h>

 /**
  * enum mcps802154_ie_state - State of information element writing.
  * @MCPS802154_IE_STATE_INIT: Initial state, no IE written.
  * @MCPS802154_IE_STATE_HEADER_IE: At least one header element written.
  * @MCPS802154_IE_STATE_PAYLOAD_IE: At least one payload element written.
  * @MCPS802154_IE_STATE_NESTED_MLME_IE: At least one payload element written,
  * the last one is a MLME IE containing at least one nested IE.
  */
 enum mcps802154_ie_state {
 	MCPS802154_IE_STATE_INIT,
 	MCPS802154_IE_STATE_HEADER_IE,
 	MCPS802154_IE_STATE_PAYLOAD_IE,
 	MCPS802154_IE_STATE_NESTED_MLME_IE,
 };

 /**
  * struct mcps802154_ie_cb - Control buffer used in sk_buff to store information
  * while building IE.
  */
 struct mcps802154_ie_cb {
 	/**
 	 * @ie_state: State of IEs writing, used to know whether a terminator is
 	 * needed or not.
 	 */
 	enum mcps802154_ie_state ie_state;
 	/**
 	 * @mlme_ie_index: Index in buffer of the MLME IE header. Valid in the
 	 * corresponding state only, used to increment IE payload length.
 	 */
 	u16 mlme_ie_index;
 	/**
 	 * @header_len: Length of frame header. Can be used for frame
 	 * encryption, the header is not encrypted but only used for
 	 * authentication.
 	 */
 	u16 header_len;
 };

 void mcps802154_ie_put_begin(struct sk_buff *skb)
 {
 	struct mcps802154_ie_cb *cb = (struct mcps802154_ie_cb *)&skb->cb;

 	cb->ie_state = MCPS802154_IE_STATE_INIT;
 	cb->header_len = skb->len;
 }
 EXPORT_SYMBOL(mcps802154_ie_put_begin);

 int mcps802154_ie_put_end(struct sk_buff *skb, bool data_payload)
 {
 	struct mcps802154_ie_cb *cb = (struct mcps802154_ie_cb *)&skb->cb;

 	if (data_payload) {
 		bool err = false;

 		if (cb->ie_state == MCPS802154_IE_STATE_HEADER_IE)
 			err = !mcps802154_ie_put_header_ie(
 				skb, IEEE802154_IE_HEADER_TERMINATION_2_ID, 0);
 		else if (cb->ie_state >= MCPS802154_IE_STATE_PAYLOAD_IE)
 			err = !mcps802154_ie_put_payload_ie(
 				skb, IEEE802154_IE_PAYLOAD_TERMINATION_GID, 0);
 		if (unlikely(err))
 			return -ENOBUFS;
 	}
 	return cb->header_len;
 }
 EXPORT_SYMBOL(mcps802154_ie_put_end);

 void *mcps802154_ie_put_header_ie(struct sk_buff *skb, int element_id,
 				  unsigned int len)
 {
 	u16 ie_header;
 	u8 *ie;
 	struct mcps802154_ie_cb *cb = (struct mcps802154_ie_cb *)&skb->cb;

 	if (unlikely(len > FIELD_MAX(IEEE802154_HEADER_IE_HEADER_LENGTH)))
 		return NULL;
 	if (unlikely(skb_tailroom(skb) < IEEE802154_IE_HEADER_LEN + len))
 		return NULL;

 	if (cb->ie_state == MCPS802154_IE_STATE_INIT)
 		skb->data[1] |= IEEE802154_FC_IE_PRESENT >> 8;
 	cb->ie_state = MCPS802154_IE_STATE_HEADER_IE;

 	ie_header =
 		FIELD_PREP(IEEE802154_HEADER_IE_HEADER_LENGTH, len) |
 		FIELD_PREP(IEEE802154_HEADER_IE_HEADER_ELEMENT_ID, element_id) |
 		IEEE802154_HEADER_IE_HEADER_TYPE;

 	ie = skb_put(skb, IEEE802154_IE_HEADER_LEN + len);
 	put_unaligned_le16(ie_header, ie);

 	cb->header_len = skb->len;

 	return ie + IEEE802154_IE_HEADER_LEN;
 }
 EXPORT_SYMBOL(mcps802154_ie_put_header_ie);

 void *mcps802154_ie_put_payload_ie(struct sk_buff *skb, int group_id,
 				   unsigned int len)
 {
 	u16 ie_header;
 	u8 *ie;
 	struct mcps802154_ie_cb *cb = (struct mcps802154_ie_cb *)&skb->cb;
 	bool need_terminator = false;

 	if (cb->ie_state < MCPS802154_IE_STATE_PAYLOAD_IE)
 		need_terminator = true;

 	if (unlikely(len > FIELD_MAX(IEEE802154_PAYLOAD_IE_HEADER_LENGTH)))
 		return NULL;
 	if (unlikely(skb_tailroom(skb) <
 		     (need_terminator ? IEEE802154_IE_HEADER_LEN : 0) +
 			     IEEE802154_IE_HEADER_LEN + len))
 		return NULL;

 	if (cb->ie_state == MCPS802154_IE_STATE_INIT)
 		skb->data[1] |= IEEE802154_FC_IE_PRESENT >> 8;
 	if (need_terminator)
 		mcps802154_ie_put_header_ie(
 			skb, IEEE802154_IE_HEADER_TERMINATION_1_ID, 0);
 	cb->ie_state = MCPS802154_IE_STATE_PAYLOAD_IE;

 	ie_header =
 		FIELD_PREP(IEEE802154_PAYLOAD_IE_HEADER_LENGTH, len) |
 		FIELD_PREP(IEEE802154_PAYLOAD_IE_HEADER_GROUP_ID, group_id) |
 		IEEE802154_PAYLOAD_IE_HEADER_TYPE;

 	ie = skb_put(skb, IEEE802154_IE_HEADER_LEN + len);
 	put_unaligned_le16(ie_header, ie);

 	return ie + IEEE802154_IE_HEADER_LEN;
 }
 EXPORT_SYMBOL(mcps802154_ie_put_payload_ie);

 void *mcps802154_ie_put_nested_mlme_ie(struct sk_buff *skb, int sub_id,
 				       unsigned int len)
 {
 	u16 ie_header;
 	u8 *ie;
 	struct mcps802154_ie_cb *cb = (struct mcps802154_ie_cb *)&skb->cb;

 	if (sub_id < IEEE802154_IE_NESTED_SHORT_MIN_SID) {
 		if (unlikely(
 			    len >
 			    FIELD_MAX(IEEE802154_LONG_NESTED_IE_HEADER_LENGTH)))
 			return NULL;
 		ie_header = FIELD_PREP(IEEE802154_LONG_NESTED_IE_HEADER_LENGTH,
 				       len) |
 			    FIELD_PREP(IEEE802154_LONG_NESTED_IE_HEADER_SUB_ID,
 				       sub_id) |
 			    IEEE802154_LONG_NESTED_IE_HEADER_TYPE;
 	} else {
 		if (unlikely(len >
 			     FIELD_MAX(
 				     IEEE802154_SHORT_NESTED_IE_HEADER_LENGTH)))
 			return NULL;
 		ie_header = FIELD_PREP(IEEE802154_SHORT_NESTED_IE_HEADER_LENGTH,
 				       len) |
 			    FIELD_PREP(IEEE802154_SHORT_NESTED_IE_HEADER_SUB_ID,
 				       sub_id) |
 			    IEEE802154_SHORT_NESTED_IE_HEADER_TYPE;
 	}

 	if (cb->ie_state != MCPS802154_IE_STATE_NESTED_MLME_IE) {
 		ie = mcps802154_ie_put_payload_ie(
 			skb, IEEE802154_IE_PAYLOAD_MLME_GID,
 			IEEE802154_IE_HEADER_LEN + len);
 		if (unlikely(!ie))
 			return NULL;
 		cb->ie_state = MCPS802154_IE_STATE_NESTED_MLME_IE;
 		cb->mlme_ie_index = ie - IEEE802154_IE_HEADER_LEN - skb->data;
 	} else {
 		u8 *mlme_ie = skb->data + cb->mlme_ie_index;
 		u16 mlme_ie_header = get_unaligned_le16(mlme_ie);
 		int mlme_len = FIELD_GET(IEEE802154_PAYLOAD_IE_HEADER_LENGTH,
 					 mlme_ie_header);

 		mlme_len += IEEE802154_IE_HEADER_LEN + len;
 		if (unlikely(mlme_len >
 			     FIELD_MAX(IEEE802154_PAYLOAD_IE_HEADER_LENGTH)))
 			return NULL;
 		mlme_ie_header = (mlme_ie_header &
 				  ~IEEE802154_PAYLOAD_IE_HEADER_LENGTH) |
 				 FIELD_PREP(IEEE802154_PAYLOAD_IE_HEADER_LENGTH,
 					    mlme_len);
 		put_unaligned_le16(mlme_ie_header, mlme_ie);

 		ie = skb_put(skb, IEEE802154_IE_HEADER_LEN + len);
 	}

 	put_unaligned_le16(ie_header, ie);

 	return ie + IEEE802154_IE_HEADER_LEN;
 }
 EXPORT_SYMBOL(mcps802154_ie_put_nested_mlme_ie);

 int mcps802154_ie_get(struct sk_buff *skb,
 		      struct mcps802154_ie_get_context *context)
 {
 	u16 ie_header;
 	bool header;
 	bool last = false;

 	if (skb->len < IEEE802154_IE_HEADER_LEN) {
 		if (context->mlme_len)
 			/* This could only happen if caller made a mistake. */
 			return -EINVAL;
 		if (skb->len > 0)
 			/* Not enough for a header, but too much for nothing. */
 			return -EBADMSG;
 		context->in_payload = true;
 		context->kind = MCPS802154_IE_GET_KIND_NONE;
 		context->id = 0;
 		context->len = 0;
 		return 1;
 	}

 	ie_header = get_unaligned_le16(skb->data);
 	skb_pull(skb, sizeof(ie_header));

 	if (context->mlme_len) {
 		context->kind = MCPS802154_IE_GET_KIND_MLME_NESTED;
 		if ((ie_header & IEEE802154_IE_HEADER_TYPE) ==
 		    IEEE802154_LONG_NESTED_IE_HEADER_TYPE) {
 			context->id = FIELD_GET(
 				IEEE802154_LONG_NESTED_IE_HEADER_SUB_ID,
 				ie_header);
 			context->len = FIELD_GET(
 				IEEE802154_LONG_NESTED_IE_HEADER_LENGTH,
 				ie_header);
 		} else {
 			context->id = FIELD_GET(
 				IEEE802154_SHORT_NESTED_IE_HEADER_SUB_ID,
 				ie_header);
 			context->len = FIELD_GET(
 				IEEE802154_SHORT_NESTED_IE_HEADER_LENGTH,
 				ie_header);
 		}
 		if (context->mlme_len < IEEE802154_IE_HEADER_LEN + context->len)
 			return -EBADMSG;
 		context->mlme_len -= IEEE802154_IE_HEADER_LEN + context->len;
 	} else {
 		header = (ie_header & IEEE802154_IE_HEADER_TYPE) ==
 			 IEEE802154_HEADER_IE_HEADER_TYPE;
 		if (header != !context->in_payload)
 			return -EBADMSG;
 		if (header) {
 			context->kind = MCPS802154_IE_GET_KIND_HEADER;
 			context->id = FIELD_GET(
 				IEEE802154_HEADER_IE_HEADER_ELEMENT_ID,
 				ie_header);
 			context->len = FIELD_GET(
 				IEEE802154_HEADER_IE_HEADER_LENGTH, ie_header);
 			if (context->id ==
 			    IEEE802154_IE_HEADER_TERMINATION_1_ID)
 				context->in_payload = true;
 			if (context->id ==
 			    IEEE802154_IE_HEADER_TERMINATION_2_ID) {
 				context->in_payload = true;
 				last = true;
 			}
 		} else {
 			context->kind = MCPS802154_IE_GET_KIND_PAYLOAD;
 			context->id =
 				FIELD_GET(IEEE802154_PAYLOAD_IE_HEADER_GROUP_ID,
 					  ie_header);
 			context->len = FIELD_GET(
 				IEEE802154_PAYLOAD_IE_HEADER_LENGTH, ie_header);
 			if (context->id ==
 			    IEEE802154_IE_PAYLOAD_TERMINATION_GID)
 				last = true;
 			else if (context->id == IEEE802154_IE_PAYLOAD_MLME_GID)
 				context->mlme_len = context->len;
 		}
 		if (skb->len < context->len)
 			return -EBADMSG;
 	}

 	return last ? 1 : 0;
 }
 EXPORT_SYMBOL(mcps802154_ie_get);
	/*
	* This file is part of the UWB stack for linux.
	*
	* Copyright (c) 2020-2021 Qorvo US, Inc.
	*
	* This software is provided under the GNU General Public License, version 2
	* (GPLv2), as well as under a Qorvo commercial license.
	*
	* You may choose to use this software under the terms of the GPLv2 License,
	* version 2 ("GPLv2"), as published by the Free Software Foundation.
	* You should have received a copy of the GPLv2 along with this program. If
	* not, see <http://www.gnu.org/licenses/>.
	*
	* This program is distributed under the GPLv2 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 GPLv2 for more
	* details.
	*
	* If you cannot meet the requirements of the GPLv2, you may not use this
	* software for any purpose without first obtaining a commercial license from
	* Qorvo. Please contact Qorvo to inquire about licensing terms.
	*/

	#include <asm/unaligned.h>
	#include <linux/bitfield.h>
	#include <linux/errno.h>
	#include <linux/kernel.h>
	#include <linux/ieee802154.h>
	#include <linux/module.h>
	#include <net/mcps802154_frame.h>

	/**
	* enum mcps802154_ie_state - State of information element writing.
	* @MCPS802154_IE_STATE_INIT: Initial state, no IE written.
	* @MCPS802154_IE_STATE_HEADER_IE: At least one header element written.
	* @MCPS802154_IE_STATE_PAYLOAD_IE: At least one payload element written.
	* @MCPS802154_IE_STATE_NESTED_MLME_IE: At least one payload element written,
	* the last one is a MLME IE containing at least one nested IE.
	*/
	enum mcps802154_ie_state {
	MCPS802154_IE_STATE_INIT,
	MCPS802154_IE_STATE_HEADER_IE,
	MCPS802154_IE_STATE_PAYLOAD_IE,
	MCPS802154_IE_STATE_NESTED_MLME_IE,
	};

	/**
	* struct mcps802154_ie_cb - Control buffer used in sk_buff to store information
	* while building IE.
	*/
	struct mcps802154_ie_cb {
	/**
	* @ie_state: State of IEs writing, used to know whether a terminator is
	* needed or not.
	*/
	enum mcps802154_ie_state ie_state;
	/**
	* @mlme_ie_index: Index in buffer of the MLME IE header. Valid in the
	* corresponding state only, used to increment IE payload length.
	*/
	u16 mlme_ie_index;
	/**
	* @header_len: Length of frame header. Can be used for frame
	* encryption, the header is not encrypted but only used for
	* authentication.
	*/
	u16 header_len;
	};

	void mcps802154_ie_put_begin(struct sk_buff *skb)
	{
	struct mcps802154_ie_cb cb = (struct mcps802154_ie_cb )&skb->cb;

	cb->ie_state = MCPS802154_IE_STATE_INIT;
	cb->header_len = skb->len;
	}
	EXPORT_SYMBOL(mcps802154_ie_put_begin);

	int mcps802154_ie_put_end(struct sk_buff *skb, bool data_payload)
	{
	struct mcps802154_ie_cb cb = (struct mcps802154_ie_cb )&skb->cb;

	if (data_payload) {
	bool err = false;

	if (cb->ie_state == MCPS802154_IE_STATE_HEADER_IE)
	err = !mcps802154_ie_put_header_ie(
	skb, IEEE802154_IE_HEADER_TERMINATION_2_ID, 0);
	else if (cb->ie_state >= MCPS802154_IE_STATE_PAYLOAD_IE)
	err = !mcps802154_ie_put_payload_ie(
	skb, IEEE802154_IE_PAYLOAD_TERMINATION_GID, 0);
	if (unlikely(err))
	return -ENOBUFS;
	}
	return cb->header_len;
	}
	EXPORT_SYMBOL(mcps802154_ie_put_end);

	void mcps802154_ie_put_header_ie(struct sk_buff skb, int element_id,
	unsigned int len)
	{
	u16 ie_header;
	u8 *ie;
	struct mcps802154_ie_cb cb = (struct mcps802154_ie_cb )&skb->cb;

	if (unlikely(len > FIELD_MAX(IEEE802154_HEADER_IE_HEADER_LENGTH)))
	return NULL;
	if (unlikely(skb_tailroom(skb) < IEEE802154_IE_HEADER_LEN + len))
	return NULL;

	if (cb->ie_state == MCPS802154_IE_STATE_INIT)
	skb->data[1] \|= IEEE802154_FC_IE_PRESENT >> 8;
	cb->ie_state = MCPS802154_IE_STATE_HEADER_IE;

	ie_header =
	FIELD_PREP(IEEE802154_HEADER_IE_HEADER_LENGTH, len) \|
	FIELD_PREP(IEEE802154_HEADER_IE_HEADER_ELEMENT_ID, element_id) \|
	IEEE802154_HEADER_IE_HEADER_TYPE;

	ie = skb_put(skb, IEEE802154_IE_HEADER_LEN + len);
	put_unaligned_le16(ie_header, ie);

	cb->header_len = skb->len;

	return ie + IEEE802154_IE_HEADER_LEN;
	}
	EXPORT_SYMBOL(mcps802154_ie_put_header_ie);

	void mcps802154_ie_put_payload_ie(struct sk_buff skb, int group_id,
	unsigned int len)
	{
	u16 ie_header;
	u8 *ie;
	struct mcps802154_ie_cb cb = (struct mcps802154_ie_cb )&skb->cb;
	bool need_terminator = false;

	if (cb->ie_state < MCPS802154_IE_STATE_PAYLOAD_IE)
	need_terminator = true;

	if (unlikely(len > FIELD_MAX(IEEE802154_PAYLOAD_IE_HEADER_LENGTH)))
	return NULL;
	if (unlikely(skb_tailroom(skb) <
	(need_terminator ? IEEE802154_IE_HEADER_LEN : 0) +
	IEEE802154_IE_HEADER_LEN + len))
	return NULL;

	if (cb->ie_state == MCPS802154_IE_STATE_INIT)
	skb->data[1] \|= IEEE802154_FC_IE_PRESENT >> 8;
	if (need_terminator)
	mcps802154_ie_put_header_ie(
	skb, IEEE802154_IE_HEADER_TERMINATION_1_ID, 0);
	cb->ie_state = MCPS802154_IE_STATE_PAYLOAD_IE;

	ie_header =
	FIELD_PREP(IEEE802154_PAYLOAD_IE_HEADER_LENGTH, len) \|
	FIELD_PREP(IEEE802154_PAYLOAD_IE_HEADER_GROUP_ID, group_id) \|
	IEEE802154_PAYLOAD_IE_HEADER_TYPE;

	ie = skb_put(skb, IEEE802154_IE_HEADER_LEN + len);
	put_unaligned_le16(ie_header, ie);

	return ie + IEEE802154_IE_HEADER_LEN;
	}
	EXPORT_SYMBOL(mcps802154_ie_put_payload_ie);

	void mcps802154_ie_put_nested_mlme_ie(struct sk_buff skb, int sub_id,
	unsigned int len)
	{
	u16 ie_header;
	u8 *ie;
	struct mcps802154_ie_cb cb = (struct mcps802154_ie_cb )&skb->cb;

	if (sub_id < IEEE802154_IE_NESTED_SHORT_MIN_SID) {
	if (unlikely(
	len >
	FIELD_MAX(IEEE802154_LONG_NESTED_IE_HEADER_LENGTH)))
	return NULL;
	ie_header = FIELD_PREP(IEEE802154_LONG_NESTED_IE_HEADER_LENGTH,
	len) \|
	FIELD_PREP(IEEE802154_LONG_NESTED_IE_HEADER_SUB_ID,
	sub_id) \|
	IEEE802154_LONG_NESTED_IE_HEADER_TYPE;
	} else {
	if (unlikely(len >
	FIELD_MAX(
	IEEE802154_SHORT_NESTED_IE_HEADER_LENGTH)))
	return NULL;
	ie_header = FIELD_PREP(IEEE802154_SHORT_NESTED_IE_HEADER_LENGTH,
	len) \|
	FIELD_PREP(IEEE802154_SHORT_NESTED_IE_HEADER_SUB_ID,
	sub_id) \|
	IEEE802154_SHORT_NESTED_IE_HEADER_TYPE;
	}

	if (cb->ie_state != MCPS802154_IE_STATE_NESTED_MLME_IE) {
	ie = mcps802154_ie_put_payload_ie(
	skb, IEEE802154_IE_PAYLOAD_MLME_GID,
	IEEE802154_IE_HEADER_LEN + len);
	if (unlikely(!ie))
	return NULL;
	cb->ie_state = MCPS802154_IE_STATE_NESTED_MLME_IE;
	cb->mlme_ie_index = ie - IEEE802154_IE_HEADER_LEN - skb->data;
	} else {
	u8 *mlme_ie = skb->data + cb->mlme_ie_index;
	u16 mlme_ie_header = get_unaligned_le16(mlme_ie);
	int mlme_len = FIELD_GET(IEEE802154_PAYLOAD_IE_HEADER_LENGTH,
	mlme_ie_header);

	mlme_len += IEEE802154_IE_HEADER_LEN + len;
	if (unlikely(mlme_len >
	FIELD_MAX(IEEE802154_PAYLOAD_IE_HEADER_LENGTH)))
	return NULL;
	mlme_ie_header = (mlme_ie_header &
	~IEEE802154_PAYLOAD_IE_HEADER_LENGTH) \|
	FIELD_PREP(IEEE802154_PAYLOAD_IE_HEADER_LENGTH,
	mlme_len);
	put_unaligned_le16(mlme_ie_header, mlme_ie);

	ie = skb_put(skb, IEEE802154_IE_HEADER_LEN + len);
	}

	put_unaligned_le16(ie_header, ie);

	return ie + IEEE802154_IE_HEADER_LEN;
	}
	EXPORT_SYMBOL(mcps802154_ie_put_nested_mlme_ie);

	int mcps802154_ie_get(struct sk_buff *skb,
	struct mcps802154_ie_get_context *context)
	{
	u16 ie_header;
	bool header;
	bool last = false;

	if (skb->len < IEEE802154_IE_HEADER_LEN) {
	if (context->mlme_len)
	/* This could only happen if caller made a mistake. */
	return -EINVAL;
	if (skb->len > 0)
	/* Not enough for a header, but too much for nothing. */
	return -EBADMSG;
	context->in_payload = true;
	context->kind = MCPS802154_IE_GET_KIND_NONE;
	context->id = 0;
	context->len = 0;
	return 1;
	}

	ie_header = get_unaligned_le16(skb->data);
	skb_pull(skb, sizeof(ie_header));

	if (context->mlme_len) {
	context->kind = MCPS802154_IE_GET_KIND_MLME_NESTED;
	if ((ie_header & IEEE802154_IE_HEADER_TYPE) ==
	IEEE802154_LONG_NESTED_IE_HEADER_TYPE) {
	context->id = FIELD_GET(
	IEEE802154_LONG_NESTED_IE_HEADER_SUB_ID,
	ie_header);
	context->len = FIELD_GET(
	IEEE802154_LONG_NESTED_IE_HEADER_LENGTH,
	ie_header);
	} else {
	context->id = FIELD_GET(
	IEEE802154_SHORT_NESTED_IE_HEADER_SUB_ID,
	ie_header);
	context->len = FIELD_GET(
	IEEE802154_SHORT_NESTED_IE_HEADER_LENGTH,
	ie_header);
	}
	if (context->mlme_len < IEEE802154_IE_HEADER_LEN + context->len)
	return -EBADMSG;
	context->mlme_len -= IEEE802154_IE_HEADER_LEN + context->len;
	} else {
	header = (ie_header & IEEE802154_IE_HEADER_TYPE) ==
	IEEE802154_HEADER_IE_HEADER_TYPE;
	if (header != !context->in_payload)
	return -EBADMSG;
	if (header) {
	context->kind = MCPS802154_IE_GET_KIND_HEADER;
	context->id = FIELD_GET(
	IEEE802154_HEADER_IE_HEADER_ELEMENT_ID,
	ie_header);
	context->len = FIELD_GET(
	IEEE802154_HEADER_IE_HEADER_LENGTH, ie_header);
	if (context->id ==
	IEEE802154_IE_HEADER_TERMINATION_1_ID)
	context->in_payload = true;
	if (context->id ==
	IEEE802154_IE_HEADER_TERMINATION_2_ID) {
	context->in_payload = true;
	last = true;
	}
	} else {
	context->kind = MCPS802154_IE_GET_KIND_PAYLOAD;
	context->id =
	FIELD_GET(IEEE802154_PAYLOAD_IE_HEADER_GROUP_ID,
	ie_header);
	context->len = FIELD_GET(
	IEEE802154_PAYLOAD_IE_HEADER_LENGTH, ie_header);
	if (context->id ==
	IEEE802154_IE_PAYLOAD_TERMINATION_GID)
	last = true;
	else if (context->id == IEEE802154_IE_PAYLOAD_MLME_GID)
	context->mlme_len = context->len;
	}
	if (skb->len < context->len)
	return -EBADMSG;
	}

	return last ? 1 : 0;
	}
	EXPORT_SYMBOL(mcps802154_ie_get);