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8788a1ee07
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
331 lines
10 KiB
C
331 lines
10 KiB
C
/*
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* Copyright 2011, Siemens AG
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* written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
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*/
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/*
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* Based on patches from Jon Smirl <jonsmirl@gmail.com>
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* Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/* Jon's code is based on 6lowpan implementation for Contiki which is:
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* Copyright (c) 2008, Swedish Institute of Computer Science.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef __6LOWPAN_H__
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#define __6LOWPAN_H__
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#include <linux/debugfs.h>
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#include <net/ipv6.h>
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#include <net/net_namespace.h>
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/* special link-layer handling */
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#include <net/mac802154.h>
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#define EUI64_ADDR_LEN 8
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#define LOWPAN_NHC_MAX_ID_LEN 1
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/* Maximum next header compression length which we currently support inclusive
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* possible inline data.
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*/
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#define LOWPAN_NHC_MAX_HDR_LEN (sizeof(struct udphdr))
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/* Max IPHC Header len without IPv6 hdr specific inline data.
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* Useful for getting the "extra" bytes we need at worst case compression.
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*
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* LOWPAN_IPHC + CID + LOWPAN_NHC_MAX_ID_LEN
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*/
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#define LOWPAN_IPHC_MAX_HEADER_LEN (2 + 1 + LOWPAN_NHC_MAX_ID_LEN)
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/* Maximum worst case IPHC header buffer size */
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#define LOWPAN_IPHC_MAX_HC_BUF_LEN (sizeof(struct ipv6hdr) + \
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LOWPAN_IPHC_MAX_HEADER_LEN + \
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LOWPAN_NHC_MAX_HDR_LEN)
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/* SCI/DCI is 4 bit width, so we have maximum 16 entries */
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#define LOWPAN_IPHC_CTX_TABLE_SIZE (1 << 4)
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#define LOWPAN_DISPATCH_IPV6 0x41 /* 01000001 = 65 */
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#define LOWPAN_DISPATCH_IPHC 0x60 /* 011xxxxx = ... */
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#define LOWPAN_DISPATCH_IPHC_MASK 0xe0
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static inline bool lowpan_is_ipv6(u8 dispatch)
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{
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return dispatch == LOWPAN_DISPATCH_IPV6;
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}
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static inline bool lowpan_is_iphc(u8 dispatch)
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{
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return (dispatch & LOWPAN_DISPATCH_IPHC_MASK) == LOWPAN_DISPATCH_IPHC;
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}
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#define LOWPAN_PRIV_SIZE(llpriv_size) \
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(sizeof(struct lowpan_dev) + llpriv_size)
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enum lowpan_lltypes {
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LOWPAN_LLTYPE_BTLE,
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LOWPAN_LLTYPE_IEEE802154,
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};
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enum lowpan_iphc_ctx_flags {
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LOWPAN_IPHC_CTX_FLAG_ACTIVE,
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LOWPAN_IPHC_CTX_FLAG_COMPRESSION,
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};
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struct lowpan_iphc_ctx {
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u8 id;
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struct in6_addr pfx;
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u8 plen;
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unsigned long flags;
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};
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struct lowpan_iphc_ctx_table {
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spinlock_t lock;
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const struct lowpan_iphc_ctx_ops *ops;
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struct lowpan_iphc_ctx table[LOWPAN_IPHC_CTX_TABLE_SIZE];
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};
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static inline bool lowpan_iphc_ctx_is_active(const struct lowpan_iphc_ctx *ctx)
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{
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return test_bit(LOWPAN_IPHC_CTX_FLAG_ACTIVE, &ctx->flags);
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}
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static inline bool
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lowpan_iphc_ctx_is_compression(const struct lowpan_iphc_ctx *ctx)
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{
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return test_bit(LOWPAN_IPHC_CTX_FLAG_COMPRESSION, &ctx->flags);
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}
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struct lowpan_dev {
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enum lowpan_lltypes lltype;
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struct dentry *iface_debugfs;
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struct lowpan_iphc_ctx_table ctx;
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/* must be last */
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u8 priv[] __aligned(sizeof(void *));
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};
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struct lowpan_802154_neigh {
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__le16 short_addr;
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};
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static inline
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struct lowpan_802154_neigh *lowpan_802154_neigh(void *neigh_priv)
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{
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return neigh_priv;
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}
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static inline
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struct lowpan_dev *lowpan_dev(const struct net_device *dev)
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{
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return netdev_priv(dev);
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}
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/* private device info */
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struct lowpan_802154_dev {
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struct net_device *wdev; /* wpan device ptr */
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u16 fragment_tag;
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};
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static inline struct
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lowpan_802154_dev *lowpan_802154_dev(const struct net_device *dev)
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{
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return (struct lowpan_802154_dev *)lowpan_dev(dev)->priv;
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}
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struct lowpan_802154_cb {
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u16 d_tag;
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unsigned int d_size;
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u8 d_offset;
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};
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static inline
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struct lowpan_802154_cb *lowpan_802154_cb(const struct sk_buff *skb)
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{
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BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(skb->cb));
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return (struct lowpan_802154_cb *)skb->cb;
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}
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static inline void lowpan_iphc_uncompress_eui64_lladdr(struct in6_addr *ipaddr,
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const void *lladdr)
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{
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/* fe:80::XXXX:XXXX:XXXX:XXXX
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* \_________________/
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* hwaddr
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*/
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ipaddr->s6_addr[0] = 0xFE;
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ipaddr->s6_addr[1] = 0x80;
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memcpy(&ipaddr->s6_addr[8], lladdr, EUI64_ADDR_LEN);
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/* second bit-flip (Universe/Local)
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* is done according RFC2464
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*/
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ipaddr->s6_addr[8] ^= 0x02;
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}
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static inline void lowpan_iphc_uncompress_eui48_lladdr(struct in6_addr *ipaddr,
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const void *lladdr)
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{
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/* fe:80::XXXX:XXff:feXX:XXXX
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* \_________________/
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* hwaddr
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*/
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ipaddr->s6_addr[0] = 0xFE;
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ipaddr->s6_addr[1] = 0x80;
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memcpy(&ipaddr->s6_addr[8], lladdr, 3);
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ipaddr->s6_addr[11] = 0xFF;
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ipaddr->s6_addr[12] = 0xFE;
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memcpy(&ipaddr->s6_addr[13], lladdr + 3, 3);
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}
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#ifdef DEBUG
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/* print data in line */
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static inline void raw_dump_inline(const char *caller, char *msg,
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const unsigned char *buf, int len)
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{
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if (msg)
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pr_debug("%s():%s: ", caller, msg);
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print_hex_dump_debug("", DUMP_PREFIX_NONE, 16, 1, buf, len, false);
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}
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/* print data in a table format:
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*
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* addr: xx xx xx xx xx xx
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* addr: xx xx xx xx xx xx
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* ...
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*/
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static inline void raw_dump_table(const char *caller, char *msg,
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const unsigned char *buf, int len)
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{
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if (msg)
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pr_debug("%s():%s:\n", caller, msg);
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print_hex_dump_debug("\t", DUMP_PREFIX_OFFSET, 16, 1, buf, len, false);
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}
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#else
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static inline void raw_dump_table(const char *caller, char *msg,
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const unsigned char *buf, int len) { }
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static inline void raw_dump_inline(const char *caller, char *msg,
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const unsigned char *buf, int len) { }
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#endif
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/**
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* lowpan_fetch_skb - getting inline data from 6LoWPAN header
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*
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* This function will pull data from sk buffer and put it into data to
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* remove the 6LoWPAN inline data. This function returns true if the
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* sk buffer is too small to pull the amount of data which is specified
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* by len.
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*
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* @skb: the buffer where the inline data should be pulled from.
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* @data: destination buffer for the inline data.
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* @len: amount of data which should be pulled in bytes.
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*/
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static inline bool lowpan_fetch_skb(struct sk_buff *skb, void *data,
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unsigned int len)
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{
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if (unlikely(!pskb_may_pull(skb, len)))
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return true;
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skb_copy_from_linear_data(skb, data, len);
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skb_pull(skb, len);
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return false;
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}
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static inline bool lowpan_802154_is_valid_src_short_addr(__le16 addr)
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{
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/* First bit of addr is multicast, reserved or 802.15.4 specific */
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return !(addr & cpu_to_le16(0x8000));
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}
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static inline void lowpan_push_hc_data(u8 **hc_ptr, const void *data,
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const size_t len)
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{
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memcpy(*hc_ptr, data, len);
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*hc_ptr += len;
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}
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int lowpan_register_netdevice(struct net_device *dev,
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enum lowpan_lltypes lltype);
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int lowpan_register_netdev(struct net_device *dev,
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enum lowpan_lltypes lltype);
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void lowpan_unregister_netdevice(struct net_device *dev);
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void lowpan_unregister_netdev(struct net_device *dev);
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/**
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* lowpan_header_decompress - replace 6LoWPAN header with IPv6 header
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*
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* This function replaces the IPHC 6LoWPAN header which should be pointed at
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* skb->data and skb_network_header, with the IPv6 header.
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* It would be nice that the caller have the necessary headroom of IPv6 header
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* and greatest Transport layer header, this would reduce the overhead for
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* reallocate headroom.
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*
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* @skb: the buffer which should be manipulate.
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* @dev: the lowpan net device pointer.
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* @daddr: destination lladdr of mac header which is used for compression
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* methods.
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* @saddr: source lladdr of mac header which is used for compression
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* methods.
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*/
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int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
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const void *daddr, const void *saddr);
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/**
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* lowpan_header_compress - replace IPv6 header with 6LoWPAN header
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*
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* This function replaces the IPv6 header which should be pointed at
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* skb->data and skb_network_header, with the IPHC 6LoWPAN header.
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* The caller need to be sure that the sk buffer is not shared and at have
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* at least a headroom which is smaller or equal LOWPAN_IPHC_MAX_HEADER_LEN,
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* which is the IPHC "more bytes than IPv6 header" at worst case.
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*
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* @skb: the buffer which should be manipulate.
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* @dev: the lowpan net device pointer.
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* @daddr: destination lladdr of mac header which is used for compression
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* methods.
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* @saddr: source lladdr of mac header which is used for compression
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* methods.
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*/
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int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
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const void *daddr, const void *saddr);
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#endif /* __6LOWPAN_H__ */
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