![Martin Townsend](/assets/img/avatar_default.png)
As we have decouple decompression from data delivery we can now rename all occurences of process_data in receive path. Signed-off-by: Martin Townsend <mtownsend1973@gmail.com> Acked-by: Alexander Aring <alex.aring@gmail.com> Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
767 lines
22 KiB
C
767 lines
22 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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/* 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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#include <linux/bitops.h>
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#include <linux/if_arp.h>
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#include <linux/module.h>
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#include <linux/netdevice.h>
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#include <net/6lowpan.h>
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#include <net/ipv6.h>
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#include <net/af_ieee802154.h>
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/* Uncompress address function for source and
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* destination address(non-multicast).
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*
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* address_mode is sam value or dam value.
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*/
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static int uncompress_addr(struct sk_buff *skb,
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struct in6_addr *ipaddr, const u8 address_mode,
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const u8 *lladdr, const u8 addr_type,
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const u8 addr_len)
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{
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bool fail;
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switch (address_mode) {
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case LOWPAN_IPHC_ADDR_00:
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/* for global link addresses */
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fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
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break;
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case LOWPAN_IPHC_ADDR_01:
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/* fe:80::XXXX:XXXX:XXXX:XXXX */
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ipaddr->s6_addr[0] = 0xFE;
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ipaddr->s6_addr[1] = 0x80;
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fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
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break;
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case LOWPAN_IPHC_ADDR_02:
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/* fe:80::ff:fe00:XXXX */
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ipaddr->s6_addr[0] = 0xFE;
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ipaddr->s6_addr[1] = 0x80;
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ipaddr->s6_addr[11] = 0xFF;
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ipaddr->s6_addr[12] = 0xFE;
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fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
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break;
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case LOWPAN_IPHC_ADDR_03:
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fail = false;
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switch (addr_type) {
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case IEEE802154_ADDR_LONG:
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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, 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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break;
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case IEEE802154_ADDR_SHORT:
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/* fe:80::ff:fe00:XXXX
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* \__/
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* short_addr
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*
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* Universe/Local bit is zero.
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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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ipaddr->s6_addr[11] = 0xFF;
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ipaddr->s6_addr[12] = 0xFE;
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ipaddr->s6_addr16[7] = htons(*((u16 *)lladdr));
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break;
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default:
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pr_debug("Invalid addr_type set\n");
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return -EINVAL;
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}
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break;
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default:
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pr_debug("Invalid address mode value: 0x%x\n", address_mode);
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return -EINVAL;
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}
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if (fail) {
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pr_debug("Failed to fetch skb data\n");
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return -EIO;
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}
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raw_dump_inline(NULL, "Reconstructed ipv6 addr is",
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ipaddr->s6_addr, 16);
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return 0;
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}
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/* Uncompress address function for source context
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* based address(non-multicast).
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*/
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static int uncompress_context_based_src_addr(struct sk_buff *skb,
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struct in6_addr *ipaddr,
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const u8 sam)
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{
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switch (sam) {
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case LOWPAN_IPHC_ADDR_00:
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/* unspec address ::
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* Do nothing, address is already ::
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*/
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break;
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case LOWPAN_IPHC_ADDR_01:
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/* TODO */
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case LOWPAN_IPHC_ADDR_02:
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/* TODO */
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case LOWPAN_IPHC_ADDR_03:
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/* TODO */
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netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
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return -EINVAL;
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default:
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pr_debug("Invalid sam value: 0x%x\n", sam);
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return -EINVAL;
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}
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raw_dump_inline(NULL,
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"Reconstructed context based ipv6 src addr is",
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ipaddr->s6_addr, 16);
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return 0;
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}
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/* Uncompress function for multicast destination address,
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* when M bit is set.
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*/
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static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
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struct in6_addr *ipaddr,
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const u8 dam)
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{
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bool fail;
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switch (dam) {
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case LOWPAN_IPHC_DAM_00:
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/* 00: 128 bits. The full address
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* is carried in-line.
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*/
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fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
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break;
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case LOWPAN_IPHC_DAM_01:
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/* 01: 48 bits. The address takes
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* the form ffXX::00XX:XXXX:XXXX.
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*/
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ipaddr->s6_addr[0] = 0xFF;
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fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
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fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
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break;
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case LOWPAN_IPHC_DAM_10:
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/* 10: 32 bits. The address takes
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* the form ffXX::00XX:XXXX.
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*/
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ipaddr->s6_addr[0] = 0xFF;
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fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
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fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
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break;
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case LOWPAN_IPHC_DAM_11:
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/* 11: 8 bits. The address takes
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* the form ff02::00XX.
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*/
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ipaddr->s6_addr[0] = 0xFF;
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ipaddr->s6_addr[1] = 0x02;
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fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
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break;
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default:
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pr_debug("DAM value has a wrong value: 0x%x\n", dam);
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return -EINVAL;
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}
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if (fail) {
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pr_debug("Failed to fetch skb data\n");
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return -EIO;
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}
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raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is",
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ipaddr->s6_addr, 16);
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return 0;
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}
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static int uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh)
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{
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bool fail;
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u8 tmp = 0, val = 0;
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fail = lowpan_fetch_skb(skb, &tmp, sizeof(tmp));
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if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
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pr_debug("UDP header uncompression\n");
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switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {
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case LOWPAN_NHC_UDP_CS_P_00:
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fail |= lowpan_fetch_skb(skb, &uh->source,
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sizeof(uh->source));
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fail |= lowpan_fetch_skb(skb, &uh->dest,
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sizeof(uh->dest));
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break;
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case LOWPAN_NHC_UDP_CS_P_01:
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fail |= lowpan_fetch_skb(skb, &uh->source,
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sizeof(uh->source));
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fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
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uh->dest = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
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break;
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case LOWPAN_NHC_UDP_CS_P_10:
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fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
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uh->source = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
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fail |= lowpan_fetch_skb(skb, &uh->dest,
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sizeof(uh->dest));
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break;
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case LOWPAN_NHC_UDP_CS_P_11:
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fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
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uh->source = htons(LOWPAN_NHC_UDP_4BIT_PORT +
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(val >> 4));
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uh->dest = htons(LOWPAN_NHC_UDP_4BIT_PORT +
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(val & 0x0f));
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break;
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default:
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pr_debug("ERROR: unknown UDP format\n");
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goto err;
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}
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pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
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ntohs(uh->source), ntohs(uh->dest));
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/* checksum */
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if (tmp & LOWPAN_NHC_UDP_CS_C) {
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pr_debug_ratelimited("checksum elided currently not supported\n");
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goto err;
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} else {
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fail |= lowpan_fetch_skb(skb, &uh->check,
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sizeof(uh->check));
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}
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/* UDP length needs to be infered from the lower layers
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* here, we obtain the hint from the remaining size of the
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* frame
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*/
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uh->len = htons(skb->len + sizeof(struct udphdr));
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pr_debug("uncompressed UDP length: src = %d", ntohs(uh->len));
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} else {
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pr_debug("ERROR: unsupported NH format\n");
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goto err;
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}
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if (fail)
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goto err;
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return 0;
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err:
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return -EINVAL;
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}
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/* TTL uncompression values */
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static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
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int
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lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
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const u8 *saddr, const u8 saddr_type,
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const u8 saddr_len, const u8 *daddr,
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const u8 daddr_type, const u8 daddr_len,
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u8 iphc0, u8 iphc1)
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{
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struct ipv6hdr hdr = {};
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u8 tmp, num_context = 0;
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int err;
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raw_dump_table(__func__, "raw skb data dump uncompressed",
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skb->data, skb->len);
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/* another if the CID flag is set */
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if (iphc1 & LOWPAN_IPHC_CID) {
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pr_debug("CID flag is set, increase header with one\n");
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if (lowpan_fetch_skb(skb, &num_context, sizeof(num_context)))
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goto drop;
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}
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hdr.version = 6;
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/* Traffic Class and Flow Label */
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switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
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/* Traffic Class and FLow Label carried in-line
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* ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
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*/
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case 0: /* 00b */
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if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
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goto drop;
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memcpy(&hdr.flow_lbl, &skb->data[0], 3);
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skb_pull(skb, 3);
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hdr.priority = ((tmp >> 2) & 0x0f);
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hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) |
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(hdr.flow_lbl[0] & 0x0f);
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break;
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/* Traffic class carried in-line
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* ECN + DSCP (1 byte), Flow Label is elided
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*/
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case 2: /* 10b */
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if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
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goto drop;
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hdr.priority = ((tmp >> 2) & 0x0f);
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hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
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break;
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/* Flow Label carried in-line
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* ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
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*/
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case 1: /* 01b */
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if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
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goto drop;
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hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30);
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memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
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skb_pull(skb, 2);
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break;
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/* Traffic Class and Flow Label are elided */
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case 3: /* 11b */
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break;
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default:
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break;
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}
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/* Next Header */
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if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
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/* Next header is carried inline */
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if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr)))
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goto drop;
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pr_debug("NH flag is set, next header carried inline: %02x\n",
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hdr.nexthdr);
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}
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/* Hop Limit */
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if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I) {
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hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];
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} else {
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if (lowpan_fetch_skb(skb, &hdr.hop_limit,
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sizeof(hdr.hop_limit)))
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goto drop;
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}
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/* Extract SAM to the tmp variable */
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tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;
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if (iphc1 & LOWPAN_IPHC_SAC) {
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/* Source address context based uncompression */
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pr_debug("SAC bit is set. Handle context based source address.\n");
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err = uncompress_context_based_src_addr(skb, &hdr.saddr, tmp);
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} else {
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/* Source address uncompression */
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pr_debug("source address stateless compression\n");
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err = uncompress_addr(skb, &hdr.saddr, tmp, saddr,
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saddr_type, saddr_len);
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}
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/* Check on error of previous branch */
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if (err)
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goto drop;
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/* Extract DAM to the tmp variable */
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tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;
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/* check for Multicast Compression */
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if (iphc1 & LOWPAN_IPHC_M) {
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if (iphc1 & LOWPAN_IPHC_DAC) {
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pr_debug("dest: context-based mcast compression\n");
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/* TODO: implement this */
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} else {
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err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
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tmp);
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if (err)
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goto drop;
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}
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} else {
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err = uncompress_addr(skb, &hdr.daddr, tmp, daddr,
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daddr_type, daddr_len);
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pr_debug("dest: stateless compression mode %d dest %pI6c\n",
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tmp, &hdr.daddr);
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if (err)
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goto drop;
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}
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/* UDP data uncompression */
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if (iphc0 & LOWPAN_IPHC_NH_C) {
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struct udphdr uh;
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const int needed = sizeof(struct udphdr) + sizeof(hdr);
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if (uncompress_udp_header(skb, &uh))
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goto drop;
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/* replace the compressed UDP head by the uncompressed UDP
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* header
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*/
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err = skb_cow(skb, needed);
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if (unlikely(err)) {
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kfree_skb(skb);
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return err;
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}
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skb_push(skb, sizeof(struct udphdr));
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skb_reset_transport_header(skb);
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skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr));
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raw_dump_table(__func__, "raw UDP header dump",
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(u8 *)&uh, sizeof(uh));
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hdr.nexthdr = UIP_PROTO_UDP;
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} else {
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err = skb_cow(skb, sizeof(hdr));
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if (unlikely(err)) {
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kfree_skb(skb);
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return err;
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}
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}
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hdr.payload_len = htons(skb->len);
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pr_debug("skb headroom size = %d, data length = %d\n",
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skb_headroom(skb), skb->len);
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pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t"
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"nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
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hdr.version, ntohs(hdr.payload_len), hdr.nexthdr,
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hdr.hop_limit, &hdr.daddr);
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skb_push(skb, sizeof(hdr));
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skb_reset_network_header(skb);
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skb_copy_to_linear_data(skb, &hdr, sizeof(hdr));
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|
|
raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
|
|
|
|
return 0;
|
|
drop:
|
|
kfree_skb(skb);
|
|
return -EINVAL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(lowpan_header_decompress);
|
|
|
|
static u8 lowpan_compress_addr_64(u8 **hc_ptr, u8 shift,
|
|
const struct in6_addr *ipaddr,
|
|
const unsigned char *lladdr)
|
|
{
|
|
u8 val = 0;
|
|
|
|
if (is_addr_mac_addr_based(ipaddr, lladdr)) {
|
|
val = 3; /* 0-bits */
|
|
pr_debug("address compression 0 bits\n");
|
|
} else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
|
|
/* compress IID to 16 bits xxxx::XXXX */
|
|
lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[7], 2);
|
|
val = 2; /* 16-bits */
|
|
raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
|
|
*hc_ptr - 2, 2);
|
|
} else {
|
|
/* do not compress IID => xxxx::IID */
|
|
lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
|
|
val = 1; /* 64-bits */
|
|
raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
|
|
*hc_ptr - 8, 8);
|
|
}
|
|
|
|
return rol8(val, shift);
|
|
}
|
|
|
|
static void compress_udp_header(u8 **hc_ptr, struct sk_buff *skb)
|
|
{
|
|
struct udphdr *uh = udp_hdr(skb);
|
|
u8 tmp;
|
|
|
|
if (((ntohs(uh->source) & LOWPAN_NHC_UDP_4BIT_MASK) ==
|
|
LOWPAN_NHC_UDP_4BIT_PORT) &&
|
|
((ntohs(uh->dest) & LOWPAN_NHC_UDP_4BIT_MASK) ==
|
|
LOWPAN_NHC_UDP_4BIT_PORT)) {
|
|
pr_debug("UDP header: both ports compression to 4 bits\n");
|
|
/* compression value */
|
|
tmp = LOWPAN_NHC_UDP_CS_P_11;
|
|
lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
|
|
/* source and destination port */
|
|
tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_4BIT_PORT +
|
|
((ntohs(uh->source) - LOWPAN_NHC_UDP_4BIT_PORT) << 4);
|
|
lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
|
|
} else if ((ntohs(uh->dest) & LOWPAN_NHC_UDP_8BIT_MASK) ==
|
|
LOWPAN_NHC_UDP_8BIT_PORT) {
|
|
pr_debug("UDP header: remove 8 bits of dest\n");
|
|
/* compression value */
|
|
tmp = LOWPAN_NHC_UDP_CS_P_01;
|
|
lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
|
|
/* source port */
|
|
lowpan_push_hc_data(hc_ptr, &uh->source, sizeof(uh->source));
|
|
/* destination port */
|
|
tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_8BIT_PORT;
|
|
lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
|
|
} else if ((ntohs(uh->source) & LOWPAN_NHC_UDP_8BIT_MASK) ==
|
|
LOWPAN_NHC_UDP_8BIT_PORT) {
|
|
pr_debug("UDP header: remove 8 bits of source\n");
|
|
/* compression value */
|
|
tmp = LOWPAN_NHC_UDP_CS_P_10;
|
|
lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
|
|
/* source port */
|
|
tmp = ntohs(uh->source) - LOWPAN_NHC_UDP_8BIT_PORT;
|
|
lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
|
|
/* destination port */
|
|
lowpan_push_hc_data(hc_ptr, &uh->dest, sizeof(uh->dest));
|
|
} else {
|
|
pr_debug("UDP header: can't compress\n");
|
|
/* compression value */
|
|
tmp = LOWPAN_NHC_UDP_CS_P_00;
|
|
lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
|
|
/* source port */
|
|
lowpan_push_hc_data(hc_ptr, &uh->source, sizeof(uh->source));
|
|
/* destination port */
|
|
lowpan_push_hc_data(hc_ptr, &uh->dest, sizeof(uh->dest));
|
|
}
|
|
|
|
/* checksum is always inline */
|
|
lowpan_push_hc_data(hc_ptr, &uh->check, sizeof(uh->check));
|
|
|
|
/* skip the UDP header */
|
|
skb_pull(skb, sizeof(struct udphdr));
|
|
}
|
|
|
|
int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
|
|
unsigned short type, const void *_daddr,
|
|
const void *_saddr, unsigned int len)
|
|
{
|
|
u8 tmp, iphc0, iphc1, *hc_ptr;
|
|
struct ipv6hdr *hdr;
|
|
u8 head[100] = {};
|
|
int addr_type;
|
|
|
|
if (type != ETH_P_IPV6)
|
|
return -EINVAL;
|
|
|
|
hdr = ipv6_hdr(skb);
|
|
hc_ptr = head + 2;
|
|
|
|
pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n"
|
|
"\tnexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
|
|
hdr->version, ntohs(hdr->payload_len), hdr->nexthdr,
|
|
hdr->hop_limit, &hdr->daddr);
|
|
|
|
raw_dump_table(__func__, "raw skb network header dump",
|
|
skb_network_header(skb), sizeof(struct ipv6hdr));
|
|
|
|
/* As we copy some bit-length fields, in the IPHC encoding bytes,
|
|
* we sometimes use |=
|
|
* If the field is 0, and the current bit value in memory is 1,
|
|
* this does not work. We therefore reset the IPHC encoding here
|
|
*/
|
|
iphc0 = LOWPAN_DISPATCH_IPHC;
|
|
iphc1 = 0;
|
|
|
|
/* TODO: context lookup */
|
|
|
|
raw_dump_inline(__func__, "saddr",
|
|
(unsigned char *)_saddr, IEEE802154_ADDR_LEN);
|
|
raw_dump_inline(__func__, "daddr",
|
|
(unsigned char *)_daddr, IEEE802154_ADDR_LEN);
|
|
|
|
raw_dump_table(__func__, "sending raw skb network uncompressed packet",
|
|
skb->data, skb->len);
|
|
|
|
/* Traffic class, flow label
|
|
* If flow label is 0, compress it. If traffic class is 0, compress it
|
|
* We have to process both in the same time as the offset of traffic
|
|
* class depends on the presence of version and flow label
|
|
*/
|
|
|
|
/* hc format of TC is ECN | DSCP , original one is DSCP | ECN */
|
|
tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4);
|
|
tmp = ((tmp & 0x03) << 6) | (tmp >> 2);
|
|
|
|
if (((hdr->flow_lbl[0] & 0x0F) == 0) &&
|
|
(hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) {
|
|
/* flow label can be compressed */
|
|
iphc0 |= LOWPAN_IPHC_FL_C;
|
|
if ((hdr->priority == 0) &&
|
|
((hdr->flow_lbl[0] & 0xF0) == 0)) {
|
|
/* compress (elide) all */
|
|
iphc0 |= LOWPAN_IPHC_TC_C;
|
|
} else {
|
|
/* compress only the flow label */
|
|
*hc_ptr = tmp;
|
|
hc_ptr += 1;
|
|
}
|
|
} else {
|
|
/* Flow label cannot be compressed */
|
|
if ((hdr->priority == 0) &&
|
|
((hdr->flow_lbl[0] & 0xF0) == 0)) {
|
|
/* compress only traffic class */
|
|
iphc0 |= LOWPAN_IPHC_TC_C;
|
|
*hc_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F);
|
|
memcpy(hc_ptr + 1, &hdr->flow_lbl[1], 2);
|
|
hc_ptr += 3;
|
|
} else {
|
|
/* compress nothing */
|
|
memcpy(hc_ptr, hdr, 4);
|
|
/* replace the top byte with new ECN | DSCP format */
|
|
*hc_ptr = tmp;
|
|
hc_ptr += 4;
|
|
}
|
|
}
|
|
|
|
/* NOTE: payload length is always compressed */
|
|
|
|
/* Next Header is compress if UDP */
|
|
if (hdr->nexthdr == UIP_PROTO_UDP)
|
|
iphc0 |= LOWPAN_IPHC_NH_C;
|
|
|
|
if ((iphc0 & LOWPAN_IPHC_NH_C) == 0)
|
|
lowpan_push_hc_data(&hc_ptr, &hdr->nexthdr,
|
|
sizeof(hdr->nexthdr));
|
|
|
|
/* Hop limit
|
|
* if 1: compress, encoding is 01
|
|
* if 64: compress, encoding is 10
|
|
* if 255: compress, encoding is 11
|
|
* else do not compress
|
|
*/
|
|
switch (hdr->hop_limit) {
|
|
case 1:
|
|
iphc0 |= LOWPAN_IPHC_TTL_1;
|
|
break;
|
|
case 64:
|
|
iphc0 |= LOWPAN_IPHC_TTL_64;
|
|
break;
|
|
case 255:
|
|
iphc0 |= LOWPAN_IPHC_TTL_255;
|
|
break;
|
|
default:
|
|
lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit,
|
|
sizeof(hdr->hop_limit));
|
|
}
|
|
|
|
addr_type = ipv6_addr_type(&hdr->saddr);
|
|
/* source address compression */
|
|
if (addr_type == IPV6_ADDR_ANY) {
|
|
pr_debug("source address is unspecified, setting SAC\n");
|
|
iphc1 |= LOWPAN_IPHC_SAC;
|
|
} else {
|
|
if (addr_type & IPV6_ADDR_LINKLOCAL) {
|
|
iphc1 |= lowpan_compress_addr_64(&hc_ptr,
|
|
LOWPAN_IPHC_SAM_BIT,
|
|
&hdr->saddr, _saddr);
|
|
pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
|
|
&hdr->saddr, iphc1);
|
|
} else {
|
|
pr_debug("send the full source address\n");
|
|
lowpan_push_hc_data(&hc_ptr, hdr->saddr.s6_addr, 16);
|
|
}
|
|
}
|
|
|
|
addr_type = ipv6_addr_type(&hdr->daddr);
|
|
/* destination address compression */
|
|
if (addr_type & IPV6_ADDR_MULTICAST) {
|
|
pr_debug("destination address is multicast: ");
|
|
iphc1 |= LOWPAN_IPHC_M;
|
|
if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) {
|
|
pr_debug("compressed to 1 octet\n");
|
|
iphc1 |= LOWPAN_IPHC_DAM_11;
|
|
/* use last byte */
|
|
lowpan_push_hc_data(&hc_ptr,
|
|
&hdr->daddr.s6_addr[15], 1);
|
|
} else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) {
|
|
pr_debug("compressed to 4 octets\n");
|
|
iphc1 |= LOWPAN_IPHC_DAM_10;
|
|
/* second byte + the last three */
|
|
lowpan_push_hc_data(&hc_ptr,
|
|
&hdr->daddr.s6_addr[1], 1);
|
|
lowpan_push_hc_data(&hc_ptr,
|
|
&hdr->daddr.s6_addr[13], 3);
|
|
} else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) {
|
|
pr_debug("compressed to 6 octets\n");
|
|
iphc1 |= LOWPAN_IPHC_DAM_01;
|
|
/* second byte + the last five */
|
|
lowpan_push_hc_data(&hc_ptr,
|
|
&hdr->daddr.s6_addr[1], 1);
|
|
lowpan_push_hc_data(&hc_ptr,
|
|
&hdr->daddr.s6_addr[11], 5);
|
|
} else {
|
|
pr_debug("using full address\n");
|
|
iphc1 |= LOWPAN_IPHC_DAM_00;
|
|
lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
|
|
}
|
|
} else {
|
|
if (addr_type & IPV6_ADDR_LINKLOCAL) {
|
|
/* TODO: context lookup */
|
|
iphc1 |= lowpan_compress_addr_64(&hc_ptr,
|
|
LOWPAN_IPHC_DAM_BIT, &hdr->daddr, _daddr);
|
|
pr_debug("dest address unicast link-local %pI6c "
|
|
"iphc1 0x%02x\n", &hdr->daddr, iphc1);
|
|
} else {
|
|
pr_debug("dest address unicast %pI6c\n", &hdr->daddr);
|
|
lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
|
|
}
|
|
}
|
|
|
|
/* UDP header compression */
|
|
if (hdr->nexthdr == UIP_PROTO_UDP)
|
|
compress_udp_header(&hc_ptr, skb);
|
|
|
|
head[0] = iphc0;
|
|
head[1] = iphc1;
|
|
|
|
skb_pull(skb, sizeof(struct ipv6hdr));
|
|
skb_reset_transport_header(skb);
|
|
memcpy(skb_push(skb, hc_ptr - head), head, hc_ptr - head);
|
|
skb_reset_network_header(skb);
|
|
|
|
pr_debug("header len %d skb %u\n", (int)(hc_ptr - head), skb->len);
|
|
|
|
raw_dump_table(__func__, "raw skb data dump compressed",
|
|
skb->data, skb->len);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(lowpan_header_compress);
|
|
|
|
MODULE_LICENSE("GPL");
|