linux/net/ieee802154/header_ops.c
Phoebe Buckheister 94b4f6c21c 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: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-14 22:15:26 -04:00

288 lines
6.0 KiB
C

/*
* 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);