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linux/net/ieee802154/6lowpan.h
Alexander Aring ce2463b283 6lowpan: lowpan_uncompress_addr with address_mode 
This patch drops the pre and postcount calculation from the
lowpan_uncompress_addr function.We use instead a switch/case
over address_mode value. The original implementation has several
bugs in this function and it was hard to decrypt how it works.
To make it maintainable and fix these bugs this patch basically
reimplements lowpan_uncompress_addr from scratch.

A list of bugs we found in the current implementation:

1) Properly support uncompression of short-address based IPv6 addresses
   (instead of basically copying garbage)

2) Fix use and uncompression of long-addresses based IPv6 addresses

3) Add missing ff:fe00 in the case of SAM/DAM = 2 and M = 0

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Reviewed-by: Werner Almesberger <werner@almesberger.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-20 13:23:12 -07:00

248 lines
8.2 KiB
C
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/*
* Copyright 2011, Siemens AG
* written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
*/
/*
* Based on patches from Jon Smirl <jonsmirl@gmail.com>
* Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.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.
*/
/* Jon's code is based on 6lowpan implementation for Contiki which is:
* Copyright (c) 2008, Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef __6LOWPAN_H__
#define __6LOWPAN_H__
#define UIP_802154_SHORTADDR_LEN 2 /* compressed ipv6 address length */
#define UIP_IPH_LEN 40 /* ipv6 fixed header size */
#define UIP_PROTO_UDP 17 /* ipv6 next header value for UDP */
#define UIP_FRAGH_LEN 8 /* ipv6 fragment header size */
/*
* ipv6 address based on mac
* second bit-flip (Universe/Local) is done according RFC2464
*/
#define is_addr_mac_addr_based(a, m) \
((((a)->s6_addr[8]) == (((m)[0]) ^ 0x02)) && \
(((a)->s6_addr[9]) == (m)[1]) && \
(((a)->s6_addr[10]) == (m)[2]) && \
(((a)->s6_addr[11]) == (m)[3]) && \
(((a)->s6_addr[12]) == (m)[4]) && \
(((a)->s6_addr[13]) == (m)[5]) && \
(((a)->s6_addr[14]) == (m)[6]) && \
(((a)->s6_addr[15]) == (m)[7]))
/* ipv6 address is unspecified */
#define is_addr_unspecified(a) \
((((a)->s6_addr32[0]) == 0) && \
(((a)->s6_addr32[1]) == 0) && \
(((a)->s6_addr32[2]) == 0) && \
(((a)->s6_addr32[3]) == 0))
/* compare ipv6 addresses prefixes */
#define ipaddr_prefixcmp(addr1, addr2, length) \
(memcmp(addr1, addr2, length >> 3) == 0)
/* local link, i.e. FE80::/10 */
#define is_addr_link_local(a) (((a)->s6_addr16[0]) == htons(0xFE80))
/*
* check whether we can compress the IID to 16 bits,
* it's possible for unicast adresses with first 49 bits are zero only.
*/
#define lowpan_is_iid_16_bit_compressable(a) \
((((a)->s6_addr16[4]) == 0) && \
(((a)->s6_addr[10]) == 0) && \
(((a)->s6_addr[11]) == 0xff) && \
(((a)->s6_addr[12]) == 0xfe) && \
(((a)->s6_addr[13]) == 0))
/* multicast address */
#define is_addr_mcast(a) (((a)->s6_addr[0]) == 0xFF)
/* check whether the 112-bit gid of the multicast address is mappable to: */
/* 9 bits, for FF02::1 (all nodes) and FF02::2 (all routers) addresses only. */
#define lowpan_is_mcast_addr_compressable(a) \
((((a)->s6_addr16[1]) == 0) && \
(((a)->s6_addr16[2]) == 0) && \
(((a)->s6_addr16[3]) == 0) && \
(((a)->s6_addr16[4]) == 0) && \
(((a)->s6_addr16[5]) == 0) && \
(((a)->s6_addr16[6]) == 0) && \
(((a)->s6_addr[14]) == 0) && \
((((a)->s6_addr[15]) == 1) || (((a)->s6_addr[15]) == 2)))
/* 48 bits, FFXX::00XX:XXXX:XXXX */
#define lowpan_is_mcast_addr_compressable48(a) \
((((a)->s6_addr16[1]) == 0) && \
(((a)->s6_addr16[2]) == 0) && \
(((a)->s6_addr16[3]) == 0) && \
(((a)->s6_addr16[4]) == 0) && \
(((a)->s6_addr[10]) == 0))
/* 32 bits, FFXX::00XX:XXXX */
#define lowpan_is_mcast_addr_compressable32(a) \
((((a)->s6_addr16[1]) == 0) && \
(((a)->s6_addr16[2]) == 0) && \
(((a)->s6_addr16[3]) == 0) && \
(((a)->s6_addr16[4]) == 0) && \
(((a)->s6_addr16[5]) == 0) && \
(((a)->s6_addr[12]) == 0))
/* 8 bits, FF02::00XX */
#define lowpan_is_mcast_addr_compressable8(a) \
((((a)->s6_addr[1]) == 2) && \
(((a)->s6_addr16[1]) == 0) && \
(((a)->s6_addr16[2]) == 0) && \
(((a)->s6_addr16[3]) == 0) && \
(((a)->s6_addr16[4]) == 0) && \
(((a)->s6_addr16[5]) == 0) && \
(((a)->s6_addr16[6]) == 0) && \
(((a)->s6_addr[14]) == 0))
#define lowpan_is_addr_broadcast(a) \
((((a)[0]) == 0xFF) && \
(((a)[1]) == 0xFF) && \
(((a)[2]) == 0xFF) && \
(((a)[3]) == 0xFF) && \
(((a)[4]) == 0xFF) && \
(((a)[5]) == 0xFF) && \
(((a)[6]) == 0xFF) && \
(((a)[7]) == 0xFF))
#define LOWPAN_DISPATCH_IPV6 0x41 /* 01000001 = 65 */
#define LOWPAN_DISPATCH_HC1 0x42 /* 01000010 = 66 */
#define LOWPAN_DISPATCH_IPHC 0x60 /* 011xxxxx = ... */
#define LOWPAN_DISPATCH_FRAG1 0xc0 /* 11000xxx */
#define LOWPAN_DISPATCH_FRAGN 0xe0 /* 11100xxx */
#define LOWPAN_DISPATCH_MASK 0xf8 /* 11111000 */
#define LOWPAN_FRAG_TIMEOUT (HZ * 60) /* time-out 60 sec */
#define LOWPAN_FRAG1_HEAD_SIZE 0x4
#define LOWPAN_FRAGN_HEAD_SIZE 0x5
/*
* According IEEE802.15.4 standard:
* - MTU is 127 octets
* - maximum MHR size is 37 octets
* - MFR size is 2 octets
*
* so minimal payload size that we may guarantee is:
* MTU - MHR - MFR = 88 octets
*/
#define LOWPAN_FRAG_SIZE 88
/*
* Values of fields within the IPHC encoding first byte
* (C stands for compressed and I for inline)
*/
#define LOWPAN_IPHC_TF 0x18
#define LOWPAN_IPHC_FL_C 0x10
#define LOWPAN_IPHC_TC_C 0x08
#define LOWPAN_IPHC_NH_C 0x04
#define LOWPAN_IPHC_TTL_1 0x01
#define LOWPAN_IPHC_TTL_64 0x02
#define LOWPAN_IPHC_TTL_255 0x03
#define LOWPAN_IPHC_TTL_I 0x00
/* Values of fields within the IPHC encoding second byte */
#define LOWPAN_IPHC_CID 0x80
#define LOWPAN_IPHC_ADDR_00 0x00
#define LOWPAN_IPHC_ADDR_01 0x01
#define LOWPAN_IPHC_ADDR_02 0x02
#define LOWPAN_IPHC_ADDR_03 0x03
#define LOWPAN_IPHC_SAC 0x40
#define LOWPAN_IPHC_SAM 0x30
#define LOWPAN_IPHC_SAM_BIT 4
#define LOWPAN_IPHC_M 0x08
#define LOWPAN_IPHC_DAC 0x04
#define LOWPAN_IPHC_DAM_00 0x00
#define LOWPAN_IPHC_DAM_01 0x01
#define LOWPAN_IPHC_DAM_10 0x02
#define LOWPAN_IPHC_DAM_11 0x03
#define LOWPAN_IPHC_DAM_BIT 0
/*
* LOWPAN_UDP encoding (works together with IPHC)
*/
#define LOWPAN_NHC_UDP_MASK 0xF8
#define LOWPAN_NHC_UDP_ID 0xF0
#define LOWPAN_NHC_UDP_CHECKSUMC 0x04
#define LOWPAN_NHC_UDP_CHECKSUMI 0x00
#define LOWPAN_NHC_UDP_4BIT_PORT 0xF0B0
#define LOWPAN_NHC_UDP_4BIT_MASK 0xFFF0
#define LOWPAN_NHC_UDP_8BIT_PORT 0xF000
#define LOWPAN_NHC_UDP_8BIT_MASK 0xFF00
/* values for port compression, _with checksum_ ie bit 5 set to 0 */
#define LOWPAN_NHC_UDP_CS_P_00 0xF0 /* all inline */
#define LOWPAN_NHC_UDP_CS_P_01 0xF1 /* source 16bit inline,
dest = 0xF0 + 8 bit inline */
#define LOWPAN_NHC_UDP_CS_P_10 0xF2 /* source = 0xF0 + 8bit inline,
dest = 16 bit inline */
#define LOWPAN_NHC_UDP_CS_P_11 0xF3 /* source & dest = 0xF0B + 4bit inline */
static inline bool lowpan_fetch_skb(struct sk_buff *skb,
void *data, const unsigned int len)
{
if (unlikely(!pskb_may_pull(skb, len)))
return true;
skb_copy_from_linear_data(skb, data, len);
skb_pull(skb, len);
return false;
}
#endif /* __6LOWPAN_H__ */
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