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ieee802154: add header structs with endiannes and operations

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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: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Phoebe Buckheister 2014-03-14 21:24:00 +01:00 committed by David S. Miller
parent b70ab2e87f
commit 94b4f6c21c
5 changed files with 401 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
include/net/ieee802154.h
View File

@ -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 */

87
include/net/ieee802154_netdev.h
View File

@ -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)
{

1
include/net/mac802154.h
View File

@ -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

3
net/ieee802154/Makefile
View File

@ -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__

287
net/ieee802154/header_ops.c Normal file
View File

@ -0,0 +1,287 @@
/*
* 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);