Commit 94b4f6c2 authored by Phoebe Buckheister's avatar Phoebe Buckheister Committed by David S. Miller
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ieee802154: add header structs with endiannes and operations 



This patch provides a set of structures to represent 802.15.4 MAC
headers, and a set of operations to push/pull/peek these structs from
skbs. We cannot simply pointer-cast the skb MAC header pointer to these
structs, because 802.15.4 headers are wildly variable - depending on the
first three bytes, virtually all other fields of the header may be
present or not, and be present with different lengths.

The new header creation/parsing routines also support 802.15.4 security
headers, which are currently not supported by the mac802154
implementation of the protocol.

Signed-off-by: default avatarPhoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b70ab2e8

include/net/ieee802154.h

+24 −4
Original line number Diff line number Diff line
@@ -42,22 +42,42 @@ 
	    (((x) << IEEE802154_FC_TYPE_SHIFT) & IEEE802154_FC_TYPE_MASK)); \

	} while (0)



#define IEEE802154_FC_SECEN		(1 << 3)

#define IEEE802154_FC_FRPEND		(1 << 4)

#define IEEE802154_FC_ACK_REQ		(1 << 5)

#define IEEE802154_FC_INTRA_PAN		(1 << 6)

#define IEEE802154_FC_SECEN_SHIFT	3

#define IEEE802154_FC_SECEN		(1 << IEEE802154_FC_SECEN_SHIFT)

#define IEEE802154_FC_FRPEND_SHIFT	4

#define IEEE802154_FC_FRPEND		(1 << IEEE802154_FC_FRPEND_SHIFT)

#define IEEE802154_FC_ACK_REQ_SHIFT	5

#define IEEE802154_FC_ACK_REQ		(1 << IEEE802154_FC_ACK_REQ_SHIFT)

#define IEEE802154_FC_INTRA_PAN_SHIFT	6

#define IEEE802154_FC_INTRA_PAN		(1 << IEEE802154_FC_INTRA_PAN_SHIFT)



#define IEEE802154_FC_SAMODE_SHIFT	14

#define IEEE802154_FC_SAMODE_MASK	(3 << IEEE802154_FC_SAMODE_SHIFT)

#define IEEE802154_FC_DAMODE_SHIFT	10

#define IEEE802154_FC_DAMODE_MASK	(3 << IEEE802154_FC_DAMODE_SHIFT)



#define IEEE802154_FC_VERSION_SHIFT	12

#define IEEE802154_FC_VERSION_MASK	(3 << IEEE802154_FC_VERSION_SHIFT)

#define IEEE802154_FC_VERSION(x)	((x & IEEE802154_FC_VERSION_MASK) >> IEEE802154_FC_VERSION_SHIFT)



#define IEEE802154_FC_SAMODE(x)		\

	(((x) & IEEE802154_FC_SAMODE_MASK) >> IEEE802154_FC_SAMODE_SHIFT)



#define IEEE802154_FC_DAMODE(x)		\

	(((x) & IEEE802154_FC_DAMODE_MASK) >> IEEE802154_FC_DAMODE_SHIFT)



#define IEEE802154_SCF_SECLEVEL_MASK		7

#define IEEE802154_SCF_SECLEVEL_SHIFT		0

#define IEEE802154_SCF_SECLEVEL(x)		(x & IEEE802154_SCF_SECLEVEL_MASK)

#define IEEE802154_SCF_KEY_ID_MODE_SHIFT	3

#define IEEE802154_SCF_KEY_ID_MODE_MASK		(3 << IEEE802154_SCF_KEY_ID_MODE_SHIFT)

#define IEEE802154_SCF_KEY_ID_MODE(x)		\

	((x & IEEE802154_SCF_KEY_ID_MODE_MASK) >> IEEE802154_SCF_KEY_ID_MODE_SHIFT)



#define IEEE802154_SCF_KEY_IMPLICIT		0

#define IEEE802154_SCF_KEY_INDEX		1

#define IEEE802154_SCF_KEY_SHORT_INDEX		2

#define IEEE802154_SCF_KEY_HW_INDEX		3



/* MAC footer size */

#define IEEE802154_MFR_SIZE	2 /* 2 octets */

include/net/ieee802154_netdev.h

+87 −0
Original line number Diff line number Diff line
@@ -28,6 +28,28 @@ 
#define IEEE802154_NETDEVICE_H



#include <net/af_ieee802154.h>

#include <linux/netdevice.h>

#include <linux/skbuff.h>



struct ieee802154_sechdr {

#if defined(__LITTLE_ENDIAN_BITFIELD)

	u8 level:3,

	   key_id_mode:2,

	   reserved:3;

#elif defined(__BIG_ENDIAN_BITFIELD)

	u8 reserved:3,

	   key_id_mode:2,

	   level:3;

#else

#error	"Please fix <asm/byteorder.h>"

#endif

	u8 key_id;

	__le32 frame_counter;

	union {

		__le32 short_src;

		__le64 extended_src;

	};

};



struct ieee802154_addr {

	u8 mode;
@@ -38,6 +60,71 @@ struct ieee802154_addr { 
	};

};



struct ieee802154_hdr_fc {

#if defined(__LITTLE_ENDIAN_BITFIELD)

	u16 type:3,

	    security_enabled:1,

	    frame_pending:1,

	    ack_request:1,

	    intra_pan:1,

	    reserved:3,

	    dest_addr_mode:2,

	    version:2,

	    source_addr_mode:2;

#elif defined(__BIG_ENDIAN_BITFIELD)

	u16 reserved:1,

	    intra_pan:1,

	    ack_request:1,

	    frame_pending:1,

	    security_enabled:1,

	    type:3,

	    source_addr_mode:2,

	    version:2,

	    dest_addr_mode:2,

	    reserved2:2;

#else

#error	"Please fix <asm/byteorder.h>"

#endif

};



struct ieee802154_hdr {

	struct ieee802154_hdr_fc fc;

	u8 seq;

	struct ieee802154_addr source;

	struct ieee802154_addr dest;

	struct ieee802154_sechdr sec;

};



/* pushes hdr onto the skb. fields of hdr->fc that can be calculated from

 * the contents of hdr will be, and the actual value of those bits in

 * hdr->fc will be ignored. this includes the INTRA_PAN bit and the frame

 * version, if SECEN is set.

 */

int ieee802154_hdr_push(struct sk_buff *skb, const struct ieee802154_hdr *hdr);



/* pulls the entire 802.15.4 header off of the skb, including the security

 * header, and performs pan id decompression

 */

int ieee802154_hdr_pull(struct sk_buff *skb, struct ieee802154_hdr *hdr);



/* parses the frame control, sequence number of address fields in a given skb

 * and stores them into hdr, performing pan id decompression and length checks

 * to be suitable for use in header_ops.parse

 */

int ieee802154_hdr_peek_addrs(const struct sk_buff *skb,

			      struct ieee802154_hdr *hdr);



static inline int ieee802154_hdr_length(struct sk_buff *skb)

{

	struct ieee802154_hdr hdr;

	int len = ieee802154_hdr_pull(skb, &hdr);



	if (len > 0)

		skb_push(skb, len);



	return len;

}



static inline bool ieee802154_addr_equal(const struct ieee802154_addr *a1,

					 const struct ieee802154_addr *a2)

{

include/net/mac802154.h

+1 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#define NET_MAC802154_H



#include <net/af_ieee802154.h>

#include <linux/skbuff.h>



/* General MAC frame format:

 *  2 bytes: Frame Control

net/ieee802154/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -3,7 +3,8 @@ obj-$(CONFIG_IEEE802154_6LOWPAN) += 6lowpan.o 
obj-$(CONFIG_6LOWPAN_IPHC) += 6lowpan_iphc.o



6lowpan-y := 6lowpan_rtnl.o reassembly.o

ieee802154-y := netlink.o nl-mac.o nl-phy.o nl_policy.o wpan-class.o

ieee802154-y := netlink.o nl-mac.o nl-phy.o nl_policy.o wpan-class.o \

                header_ops.o

af_802154-y := af_ieee802154.o raw.o dgram.o



ccflags-y += -D__CHECK_ENDIAN__

net/ieee802154/header_ops.c

0 → 100644
+287 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2014 Fraunhofer ITWM

 *

 * 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.

 *

 * Written by:

 * Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>

 */



#include <net/mac802154.h>

#include <net/ieee802154.h>

#include <net/ieee802154_netdev.h>



static int

ieee802154_hdr_push_addr(u8 *buf, const struct ieee802154_addr *addr,

			 bool omit_pan)

{

	int pos = 0;



	if (addr->mode == IEEE802154_ADDR_NONE)

		return 0;



	if (!omit_pan) {

		memcpy(buf + pos, &addr->pan_id, 2);

		pos += 2;

	}



	switch (addr->mode) {

	case IEEE802154_ADDR_SHORT:

		memcpy(buf + pos, &addr->short_addr, 2);

		pos += 2;

		break;



	case IEEE802154_ADDR_LONG:

		memcpy(buf + pos, &addr->extended_addr, IEEE802154_ADDR_LEN);

		pos += IEEE802154_ADDR_LEN;

		break;



	default:

		return -EINVAL;

	}



	return pos;

}



static int

ieee802154_hdr_push_sechdr(u8 *buf, const struct ieee802154_sechdr *hdr)

{

	int pos = 5;



	memcpy(buf, hdr, 1);

	memcpy(buf + 1, &hdr->frame_counter, 4);



	switch (hdr->key_id_mode) {

	case IEEE802154_SCF_KEY_IMPLICIT:

		return pos;



	case IEEE802154_SCF_KEY_INDEX:

		break;



	case IEEE802154_SCF_KEY_SHORT_INDEX:

		memcpy(buf + pos, &hdr->short_src, 4);

		pos += 4;

		break;



	case IEEE802154_SCF_KEY_HW_INDEX:

		memcpy(buf + pos, &hdr->extended_src, IEEE802154_ADDR_LEN);

		pos += IEEE802154_ADDR_LEN;

		break;

	}



	buf[pos++] = hdr->key_id;



	return pos;

}



int

ieee802154_hdr_push(struct sk_buff *skb, const struct ieee802154_hdr *hdr)

{

	u8 buf[MAC802154_FRAME_HARD_HEADER_LEN];

	int pos = 2;

	int rc;

	struct ieee802154_hdr_fc fc = hdr->fc;



	buf[pos++] = hdr->seq;



	fc.dest_addr_mode = hdr->dest.mode;



	rc = ieee802154_hdr_push_addr(buf + pos, &hdr->dest, false);

	if (rc < 0)

		return -EINVAL;

	pos += rc;



	fc.source_addr_mode = hdr->source.mode;



	if (hdr->source.pan_id == hdr->dest.pan_id &&

	    hdr->dest.mode != IEEE802154_ADDR_NONE)

		fc.intra_pan = true;



	rc = ieee802154_hdr_push_addr(buf + pos, &hdr->source, fc.intra_pan);

	if (rc < 0)

		return -EINVAL;

	pos += rc;



	if (fc.security_enabled) {

		fc.version = 1;



		rc = ieee802154_hdr_push_sechdr(buf + pos, &hdr->sec);

		if (rc < 0)

			return -EINVAL;



		pos += rc;

	}



	memcpy(buf, &fc, 2);



	memcpy(skb_push(skb, pos), buf, pos);



	return pos;

}

EXPORT_SYMBOL_GPL(ieee802154_hdr_push);



static int

ieee802154_hdr_get_addr(const u8 *buf, int mode, bool omit_pan,

			struct ieee802154_addr *addr)

{

	int pos = 0;



	addr->mode = mode;



	if (mode == IEEE802154_ADDR_NONE)

		return 0;



	if (!omit_pan) {

		memcpy(&addr->pan_id, buf + pos, 2);

		pos += 2;

	}



	if (mode == IEEE802154_ADDR_SHORT) {

		memcpy(&addr->short_addr, buf + pos, 2);

		return pos + 2;

	} else {

		memcpy(&addr->extended_addr, buf + pos, IEEE802154_ADDR_LEN);

		return pos + IEEE802154_ADDR_LEN;

	}

}



static int ieee802154_hdr_addr_len(int mode, bool omit_pan)

{

	int pan_len = omit_pan ? 0 : 2;



	switch (mode) {

	case IEEE802154_ADDR_NONE: return 0;

	case IEEE802154_ADDR_SHORT: return 2 + pan_len;

	case IEEE802154_ADDR_LONG: return IEEE802154_ADDR_LEN + pan_len;

	default: return -EINVAL;

	}

}



static int

ieee802154_hdr_get_sechdr(const u8 *buf, struct ieee802154_sechdr *hdr)

{

	int pos = 5;



	memcpy(hdr, buf, 1);

	memcpy(&hdr->frame_counter, buf + 1, 4);



	switch (hdr->key_id_mode) {

	case IEEE802154_SCF_KEY_IMPLICIT:

		return pos;



	case IEEE802154_SCF_KEY_INDEX:

		break;



	case IEEE802154_SCF_KEY_SHORT_INDEX:

		memcpy(&hdr->short_src, buf + pos, 4);

		pos += 4;

		break;



	case IEEE802154_SCF_KEY_HW_INDEX:

		memcpy(&hdr->extended_src, buf + pos, IEEE802154_ADDR_LEN);

		pos += IEEE802154_ADDR_LEN;

		break;

	}



	hdr->key_id = buf[pos++];



	return pos;

}



static int ieee802154_hdr_sechdr_len(u8 sc)

{

	switch (IEEE802154_SCF_KEY_ID_MODE(sc)) {

	case IEEE802154_SCF_KEY_IMPLICIT: return 5;

	case IEEE802154_SCF_KEY_INDEX: return 6;

	case IEEE802154_SCF_KEY_SHORT_INDEX: return 10;

	case IEEE802154_SCF_KEY_HW_INDEX: return 14;

	default: return -EINVAL;

	}

}



static int ieee802154_hdr_minlen(const struct ieee802154_hdr *hdr)

{

	int dlen, slen;



	dlen = ieee802154_hdr_addr_len(hdr->fc.dest_addr_mode, false);

	slen = ieee802154_hdr_addr_len(hdr->fc.source_addr_mode,

				       hdr->fc.intra_pan);



	if (slen < 0 || dlen < 0)

		return -EINVAL;



	return 3 + dlen + slen + hdr->fc.security_enabled;

}



static int

ieee802154_hdr_get_addrs(const u8 *buf, struct ieee802154_hdr *hdr)

{

	int pos = 0;



	pos += ieee802154_hdr_get_addr(buf + pos, hdr->fc.dest_addr_mode,

				       false, &hdr->dest);

	pos += ieee802154_hdr_get_addr(buf + pos, hdr->fc.source_addr_mode,

				       hdr->fc.intra_pan, &hdr->source);



	if (hdr->fc.intra_pan)

		hdr->source.pan_id = hdr->dest.pan_id;



	return pos;

}



int

ieee802154_hdr_pull(struct sk_buff *skb, struct ieee802154_hdr *hdr)

{

	int pos = 3, rc;



	if (!pskb_may_pull(skb, 3))

		return -EINVAL;



	memcpy(hdr, skb->data, 3);



	rc = ieee802154_hdr_minlen(hdr);

	if (rc < 0 || !pskb_may_pull(skb, rc))

		return -EINVAL;



	pos += ieee802154_hdr_get_addrs(skb->data + pos, hdr);



	if (hdr->fc.security_enabled) {

		int want = pos + ieee802154_hdr_sechdr_len(skb->data[pos]);



		if (!pskb_may_pull(skb, want))

			return -EINVAL;



		pos += ieee802154_hdr_get_sechdr(skb->data + pos, &hdr->sec);

	}



	skb_pull(skb, pos);

	return pos;

}

EXPORT_SYMBOL_GPL(ieee802154_hdr_pull);



int

ieee802154_hdr_peek_addrs(const struct sk_buff *skb, struct ieee802154_hdr *hdr)

{

	const u8 *buf = skb_mac_header(skb);

	int pos = 3, rc;



	if (buf + 3 > skb_tail_pointer(skb))

		return -EINVAL;



	memcpy(hdr, buf, 3);



	rc = ieee802154_hdr_minlen(hdr);

	if (rc < 0 || buf + rc > skb_tail_pointer(skb))

		return -EINVAL;



	pos += ieee802154_hdr_get_addrs(buf + pos, hdr);

	return pos;

}

EXPORT_SYMBOL_GPL(ieee802154_hdr_peek_addrs);

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