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linux/net/6lowpan/iphc.c
Michael Scott 03bc05e1a4 6lowpan: iphc: reset mac_header after decompress to fix panic 
After decompression of 6lowpan socket data, an IPv6 header is inserted
before the existing socket payload.  After this, we reset the
network_header value of the skb to account for the difference in payload
size from prior to decompression + the addition of the IPv6 header.

However, we fail to reset the mac_header value.

Leaving the mac_header value untouched here, can cause a calculation
error in net/packet/af_packet.c packet_rcv() function when an
AF_PACKET socket is opened in SOCK_RAW mode for use on a 6lowpan
interface.

On line 2088, the data pointer is moved backward by the value returned
from skb_mac_header().  If skb->data is adjusted so that it is before
the skb->head pointer (which can happen when an old value of mac_header
is left in place) the kernel generates a panic in net/core/skbuff.c
line 1717.

This panic can be generated by BLE 6lowpan interfaces (such as bt0) and
802.15.4 interfaces (such as lowpan0) as they both use the same 6lowpan
sources for compression and decompression.

Signed-off-by: Michael Scott <michael@opensourcefoundries.com>
Acked-by: Alexander Aring <aring@mojatatu.com>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2018-07-06 12:32:12 +02:00

1314 lines
37 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.
*
*/
/* 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.
*/
#include <linux/bitops.h>
#include <linux/if_arp.h>
#include <linux/netdevice.h>
#include <net/6lowpan.h>
#include <net/ipv6.h>
#include "6lowpan_i.h"
#include "nhc.h"
/* Values of fields within the IPHC encoding first byte */
#define LOWPAN_IPHC_TF_MASK 0x18
#define LOWPAN_IPHC_TF_00 0x00
#define LOWPAN_IPHC_TF_01 0x08
#define LOWPAN_IPHC_TF_10 0x10
#define LOWPAN_IPHC_TF_11 0x18
#define LOWPAN_IPHC_NH 0x04
#define LOWPAN_IPHC_HLIM_MASK 0x03
#define LOWPAN_IPHC_HLIM_00 0x00
#define LOWPAN_IPHC_HLIM_01 0x01
#define LOWPAN_IPHC_HLIM_10 0x02
#define LOWPAN_IPHC_HLIM_11 0x03
/* Values of fields within the IPHC encoding second byte */
#define LOWPAN_IPHC_CID 0x80
#define LOWPAN_IPHC_SAC 0x40
#define LOWPAN_IPHC_SAM_MASK 0x30
#define LOWPAN_IPHC_SAM_00 0x00
#define LOWPAN_IPHC_SAM_01 0x10
#define LOWPAN_IPHC_SAM_10 0x20
#define LOWPAN_IPHC_SAM_11 0x30
#define LOWPAN_IPHC_M 0x08
#define LOWPAN_IPHC_DAC 0x04
#define LOWPAN_IPHC_DAM_MASK 0x03
#define LOWPAN_IPHC_DAM_00 0x00
#define LOWPAN_IPHC_DAM_01 0x01
#define LOWPAN_IPHC_DAM_10 0x02
#define LOWPAN_IPHC_DAM_11 0x03
/* 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]))
/* check whether we can compress the IID to 16 bits,
* it's possible for unicast addresses 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))
/* check whether the 112-bit gid of the multicast address is mappable to: */
/* 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_linklocal_zero_padded(a) \
(!(hdr->saddr.s6_addr[1] & 0x3f) && \
!hdr->saddr.s6_addr16[1] && \
!hdr->saddr.s6_addr32[1])
#define LOWPAN_IPHC_CID_DCI(cid) (cid & 0x0f)
#define LOWPAN_IPHC_CID_SCI(cid) ((cid & 0xf0) >> 4)
static inline void
lowpan_iphc_uncompress_802154_lladdr(struct in6_addr *ipaddr,
const void *lladdr)
{
const struct ieee802154_addr *addr = lladdr;
u8 eui64[EUI64_ADDR_LEN];
switch (addr->mode) {
case IEEE802154_ADDR_LONG:
ieee802154_le64_to_be64(eui64, &addr->extended_addr);
lowpan_iphc_uncompress_eui64_lladdr(ipaddr, eui64);
break;
case IEEE802154_ADDR_SHORT:
/* fe:80::ff:fe00:XXXX
* \__/
* short_addr
*
* Universe/Local bit is zero.
*/
ipaddr->s6_addr[0] = 0xFE;
ipaddr->s6_addr[1] = 0x80;
ipaddr->s6_addr[11] = 0xFF;
ipaddr->s6_addr[12] = 0xFE;
ieee802154_le16_to_be16(&ipaddr->s6_addr16[7],
&addr->short_addr);
break;
default:
/* should never handled and filtered by 802154 6lowpan */
WARN_ON_ONCE(1);
break;
}
}
static struct lowpan_iphc_ctx *
lowpan_iphc_ctx_get_by_id(const struct net_device *dev, u8 id)
{
struct lowpan_iphc_ctx *ret = &lowpan_dev(dev)->ctx.table[id];
if (!lowpan_iphc_ctx_is_active(ret))
return NULL;
return ret;
}
static struct lowpan_iphc_ctx *
lowpan_iphc_ctx_get_by_addr(const struct net_device *dev,
const struct in6_addr *addr)
{
struct lowpan_iphc_ctx *table = lowpan_dev(dev)->ctx.table;
struct lowpan_iphc_ctx *ret = NULL;
struct in6_addr addr_pfx;
u8 addr_plen;
int i;
for (i = 0; i < LOWPAN_IPHC_CTX_TABLE_SIZE; i++) {
/* Check if context is valid. A context that is not valid
* MUST NOT be used for compression.
*/
if (!lowpan_iphc_ctx_is_active(&table[i]) ||
!lowpan_iphc_ctx_is_compression(&table[i]))
continue;
ipv6_addr_prefix(&addr_pfx, addr, table[i].plen);
/* if prefix len < 64, the remaining bits until 64th bit is
* zero. Otherwise we use table[i]->plen.
*/
if (table[i].plen < 64)
addr_plen = 64;
else
addr_plen = table[i].plen;
if (ipv6_prefix_equal(&addr_pfx, &table[i].pfx, addr_plen)) {
/* remember first match */
if (!ret) {
ret = &table[i];
continue;
}
/* get the context with longest prefix len */
if (table[i].plen > ret->plen)
ret = &table[i];
}
}
return ret;
}
static struct lowpan_iphc_ctx *
lowpan_iphc_ctx_get_by_mcast_addr(const struct net_device *dev,
const struct in6_addr *addr)
{
struct lowpan_iphc_ctx *table = lowpan_dev(dev)->ctx.table;
struct lowpan_iphc_ctx *ret = NULL;
struct in6_addr addr_mcast, network_pfx = {};
int i;
/* init mcast address with */
memcpy(&addr_mcast, addr, sizeof(*addr));
for (i = 0; i < LOWPAN_IPHC_CTX_TABLE_SIZE; i++) {
/* Check if context is valid. A context that is not valid
* MUST NOT be used for compression.
*/
if (!lowpan_iphc_ctx_is_active(&table[i]) ||
!lowpan_iphc_ctx_is_compression(&table[i]))
continue;
/* setting plen */
addr_mcast.s6_addr[3] = table[i].plen;
/* get network prefix to copy into multicast address */
ipv6_addr_prefix(&network_pfx, &table[i].pfx,
table[i].plen);
/* setting network prefix */
memcpy(&addr_mcast.s6_addr[4], &network_pfx, 8);
if (ipv6_addr_equal(addr, &addr_mcast)) {
ret = &table[i];
break;
}
}
return ret;
}
static void lowpan_iphc_uncompress_lladdr(const struct net_device *dev,
struct in6_addr *ipaddr,
const void *lladdr)
{
switch (dev->addr_len) {
case ETH_ALEN:
lowpan_iphc_uncompress_eui48_lladdr(ipaddr, lladdr);
break;
case EUI64_ADDR_LEN:
lowpan_iphc_uncompress_eui64_lladdr(ipaddr, lladdr);
break;
default:
WARN_ON_ONCE(1);
break;
}
}
/* Uncompress address function for source and
* destination address(non-multicast).
*
* address_mode is the masked value for sam or dam value
*/
static int lowpan_iphc_uncompress_addr(struct sk_buff *skb,
const struct net_device *dev,
struct in6_addr *ipaddr,
u8 address_mode, const void *lladdr)
{
bool fail;
switch (address_mode) {
/* SAM and DAM are the same here */
case LOWPAN_IPHC_DAM_00:
/* for global link addresses */
fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
break;
case LOWPAN_IPHC_SAM_01:
case LOWPAN_IPHC_DAM_01:
/* fe:80::XXXX:XXXX:XXXX:XXXX */
ipaddr->s6_addr[0] = 0xFE;
ipaddr->s6_addr[1] = 0x80;
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
break;
case LOWPAN_IPHC_SAM_10:
case LOWPAN_IPHC_DAM_10:
/* fe:80::ff:fe00:XXXX */
ipaddr->s6_addr[0] = 0xFE;
ipaddr->s6_addr[1] = 0x80;
ipaddr->s6_addr[11] = 0xFF;
ipaddr->s6_addr[12] = 0xFE;
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
break;
case LOWPAN_IPHC_SAM_11:
case LOWPAN_IPHC_DAM_11:
fail = false;
switch (lowpan_dev(dev)->lltype) {
case LOWPAN_LLTYPE_IEEE802154:
lowpan_iphc_uncompress_802154_lladdr(ipaddr, lladdr);
break;
default:
lowpan_iphc_uncompress_lladdr(dev, ipaddr, lladdr);
break;
}
break;
default:
pr_debug("Invalid address mode value: 0x%x\n", address_mode);
return -EINVAL;
}
if (fail) {
pr_debug("Failed to fetch skb data\n");
return -EIO;
}
raw_dump_inline(NULL, "Reconstructed ipv6 addr is",
ipaddr->s6_addr, 16);
return 0;
}
/* Uncompress address function for source context
* based address(non-multicast).
*/
static int lowpan_iphc_uncompress_ctx_addr(struct sk_buff *skb,
const struct net_device *dev,
const struct lowpan_iphc_ctx *ctx,
struct in6_addr *ipaddr,
u8 address_mode, const void *lladdr)
{
bool fail;
switch (address_mode) {
/* SAM and DAM are the same here */
case LOWPAN_IPHC_DAM_00:
fail = false;
/* SAM_00 -> unspec address ::
* Do nothing, address is already ::
*
* DAM 00 -> reserved should never occur.
*/
break;
case LOWPAN_IPHC_SAM_01:
case LOWPAN_IPHC_DAM_01:
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
break;
case LOWPAN_IPHC_SAM_10:
case LOWPAN_IPHC_DAM_10:
ipaddr->s6_addr[11] = 0xFF;
ipaddr->s6_addr[12] = 0xFE;
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
break;
case LOWPAN_IPHC_SAM_11:
case LOWPAN_IPHC_DAM_11:
fail = false;
switch (lowpan_dev(dev)->lltype) {
case LOWPAN_LLTYPE_IEEE802154:
lowpan_iphc_uncompress_802154_lladdr(ipaddr, lladdr);
break;
default:
lowpan_iphc_uncompress_lladdr(dev, ipaddr, lladdr);
break;
}
ipv6_addr_prefix_copy(ipaddr, &ctx->pfx, ctx->plen);
break;
default:
pr_debug("Invalid sam value: 0x%x\n", address_mode);
return -EINVAL;
}
if (fail) {
pr_debug("Failed to fetch skb data\n");
return -EIO;
}
raw_dump_inline(NULL,
"Reconstructed context based ipv6 src addr is",
ipaddr->s6_addr, 16);
return 0;
}
/* Uncompress function for multicast destination address,
* when M bit is set.
*/
static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
struct in6_addr *ipaddr,
u8 address_mode)
{
bool fail;
switch (address_mode) {
case LOWPAN_IPHC_DAM_00:
/* 00: 128 bits. The full address
* is carried in-line.
*/
fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
break;
case LOWPAN_IPHC_DAM_01:
/* 01: 48 bits. The address takes
* the form ffXX::00XX:XXXX:XXXX.
*/
ipaddr->s6_addr[0] = 0xFF;
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
break;
case LOWPAN_IPHC_DAM_10:
/* 10: 32 bits. The address takes
* the form ffXX::00XX:XXXX.
*/
ipaddr->s6_addr[0] = 0xFF;
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
break;
case LOWPAN_IPHC_DAM_11:
/* 11: 8 bits. The address takes
* the form ff02::00XX.
*/
ipaddr->s6_addr[0] = 0xFF;
ipaddr->s6_addr[1] = 0x02;
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
break;
default:
pr_debug("DAM value has a wrong value: 0x%x\n", address_mode);
return -EINVAL;
}
if (fail) {
pr_debug("Failed to fetch skb data\n");
return -EIO;
}
raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is",
ipaddr->s6_addr, 16);
return 0;
}
static int lowpan_uncompress_multicast_ctx_daddr(struct sk_buff *skb,
struct lowpan_iphc_ctx *ctx,
struct in6_addr *ipaddr,
u8 address_mode)
{
struct in6_addr network_pfx = {};
bool fail;
ipaddr->s6_addr[0] = 0xFF;
fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 2);
fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[12], 4);
if (fail)
return -EIO;
/* take prefix_len and network prefix from the context */
ipaddr->s6_addr[3] = ctx->plen;
/* get network prefix to copy into multicast address */
ipv6_addr_prefix(&network_pfx, &ctx->pfx, ctx->plen);
/* setting network prefix */
memcpy(&ipaddr->s6_addr[4], &network_pfx, 8);
return 0;
}
/* get the ecn values from iphc tf format and set it to ipv6hdr */
static inline void lowpan_iphc_tf_set_ecn(struct ipv6hdr *hdr, const u8 *tf)
{
/* get the two higher bits which is ecn */
u8 ecn = tf[0] & 0xc0;
/* ECN takes 0x30 in hdr->flow_lbl[0] */
hdr->flow_lbl[0] |= (ecn >> 2);
}
/* get the dscp values from iphc tf format and set it to ipv6hdr */
static inline void lowpan_iphc_tf_set_dscp(struct ipv6hdr *hdr, const u8 *tf)
{
/* DSCP is at place after ECN */
u8 dscp = tf[0] & 0x3f;
/* The four highest bits need to be set at hdr->priority */
hdr->priority |= ((dscp & 0x3c) >> 2);
/* The two lower bits is part of hdr->flow_lbl[0] */
hdr->flow_lbl[0] |= ((dscp & 0x03) << 6);
}
/* get the flow label values from iphc tf format and set it to ipv6hdr */
static inline void lowpan_iphc_tf_set_lbl(struct ipv6hdr *hdr, const u8 *lbl)
{
/* flow label is always some array started with lower nibble of
* flow_lbl[0] and followed with two bytes afterwards. Inside inline
* data the flow_lbl position can be different, which will be handled
* by lbl pointer. E.g. case "01" vs "00" the traffic class is 8 bit
* shifted, the different lbl pointer will handle that.
*
* The flow label will started at lower nibble of flow_lbl[0], the
* higher nibbles are part of DSCP + ECN.
*/
hdr->flow_lbl[0] |= lbl[0] & 0x0f;
memcpy(&hdr->flow_lbl[1], &lbl[1], 2);
}
/* lowpan_iphc_tf_decompress - decompress the traffic class.
* This function will return zero on success, a value lower than zero if
* failed.
*/
static int lowpan_iphc_tf_decompress(struct sk_buff *skb, struct ipv6hdr *hdr,
u8 val)
{
u8 tf[4];
/* Traffic Class and Flow Label */
switch (val) {
case LOWPAN_IPHC_TF_00:
/* ECN + DSCP + 4-bit Pad + Flow Label (4 bytes) */
if (lowpan_fetch_skb(skb, tf, 4))
return -EINVAL;
/* 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |ECN| DSCP | rsv | Flow Label |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
lowpan_iphc_tf_set_ecn(hdr, tf);
lowpan_iphc_tf_set_dscp(hdr, tf);
lowpan_iphc_tf_set_lbl(hdr, &tf[1]);
break;
case LOWPAN_IPHC_TF_01:
/* ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided. */
if (lowpan_fetch_skb(skb, tf, 3))
return -EINVAL;
/* 1 2
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |ECN|rsv| Flow Label |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
lowpan_iphc_tf_set_ecn(hdr, tf);
lowpan_iphc_tf_set_lbl(hdr, &tf[0]);
break;
case LOWPAN_IPHC_TF_10:
/* ECN + DSCP (1 byte), Flow Label is elided. */
if (lowpan_fetch_skb(skb, tf, 1))
return -EINVAL;
/* 0 1 2 3 4 5 6 7
* +-+-+-+-+-+-+-+-+
* |ECN| DSCP |
* +-+-+-+-+-+-+-+-+
*/
lowpan_iphc_tf_set_ecn(hdr, tf);
lowpan_iphc_tf_set_dscp(hdr, tf);
break;
case LOWPAN_IPHC_TF_11:
/* Traffic Class and Flow Label are elided */
break;
default:
WARN_ON_ONCE(1);
return -EINVAL;
}
return 0;
}
/* TTL uncompression values */
static const u8 lowpan_ttl_values[] = {
[LOWPAN_IPHC_HLIM_01] = 1,
[LOWPAN_IPHC_HLIM_10] = 64,
[LOWPAN_IPHC_HLIM_11] = 255,
};
int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
const void *daddr, const void *saddr)
{
struct ipv6hdr hdr = {};
struct lowpan_iphc_ctx *ci;
u8 iphc0, iphc1, cid = 0;
int err;
raw_dump_table(__func__, "raw skb data dump uncompressed",
skb->data, skb->len);
if (lowpan_fetch_skb(skb, &iphc0, sizeof(iphc0)) ||
lowpan_fetch_skb(skb, &iphc1, sizeof(iphc1)))
return -EINVAL;
hdr.version = 6;
/* default CID = 0, another if the CID flag is set */
if (iphc1 & LOWPAN_IPHC_CID) {
if (lowpan_fetch_skb(skb, &cid, sizeof(cid)))
return -EINVAL;
}
err = lowpan_iphc_tf_decompress(skb, &hdr,
iphc0 & LOWPAN_IPHC_TF_MASK);
if (err < 0)
return err;
/* Next Header */
if (!(iphc0 & LOWPAN_IPHC_NH)) {
/* Next header is carried inline */
if (lowpan_fetch_skb(skb, &hdr.nexthdr, sizeof(hdr.nexthdr)))
return -EINVAL;
pr_debug("NH flag is set, next header carried inline: %02x\n",
hdr.nexthdr);
}
/* Hop Limit */
if ((iphc0 & LOWPAN_IPHC_HLIM_MASK) != LOWPAN_IPHC_HLIM_00) {
hdr.hop_limit = lowpan_ttl_values[iphc0 & LOWPAN_IPHC_HLIM_MASK];
} else {
if (lowpan_fetch_skb(skb, &hdr.hop_limit,
sizeof(hdr.hop_limit)))
return -EINVAL;
}
if (iphc1 & LOWPAN_IPHC_SAC) {
spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_SCI(cid));
if (!ci) {
spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
return -EINVAL;
}
pr_debug("SAC bit is set. Handle context based source address.\n");
err = lowpan_iphc_uncompress_ctx_addr(skb, dev, ci, &hdr.saddr,
iphc1 & LOWPAN_IPHC_SAM_MASK,
saddr);
spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
} else {
/* Source address uncompression */
pr_debug("source address stateless compression\n");
err = lowpan_iphc_uncompress_addr(skb, dev, &hdr.saddr,
iphc1 & LOWPAN_IPHC_SAM_MASK,
saddr);
}
/* Check on error of previous branch */
if (err)
return -EINVAL;
switch (iphc1 & (LOWPAN_IPHC_M | LOWPAN_IPHC_DAC)) {
case LOWPAN_IPHC_M | LOWPAN_IPHC_DAC:
skb->pkt_type = PACKET_BROADCAST;
spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_DCI(cid));
if (!ci) {
spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
return -EINVAL;
}
/* multicast with context */
pr_debug("dest: context-based mcast compression\n");
err = lowpan_uncompress_multicast_ctx_daddr(skb, ci,
&hdr.daddr,
iphc1 & LOWPAN_IPHC_DAM_MASK);
spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
break;
case LOWPAN_IPHC_M:
skb->pkt_type = PACKET_BROADCAST;
/* multicast */
err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
iphc1 & LOWPAN_IPHC_DAM_MASK);
break;
case LOWPAN_IPHC_DAC:
skb->pkt_type = PACKET_HOST;
spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
ci = lowpan_iphc_ctx_get_by_id(dev, LOWPAN_IPHC_CID_DCI(cid));
if (!ci) {
spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
return -EINVAL;
}
/* Destination address context based uncompression */
pr_debug("DAC bit is set. Handle context based destination address.\n");
err = lowpan_iphc_uncompress_ctx_addr(skb, dev, ci, &hdr.daddr,
iphc1 & LOWPAN_IPHC_DAM_MASK,
daddr);
spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
break;
default:
skb->pkt_type = PACKET_HOST;
err = lowpan_iphc_uncompress_addr(skb, dev, &hdr.daddr,
iphc1 & LOWPAN_IPHC_DAM_MASK,
daddr);
pr_debug("dest: stateless compression mode %d dest %pI6c\n",
iphc1 & LOWPAN_IPHC_DAM_MASK, &hdr.daddr);
break;
}
if (err)
return -EINVAL;
/* Next header data uncompression */
if (iphc0 & LOWPAN_IPHC_NH) {
err = lowpan_nhc_do_uncompression(skb, dev, &hdr);
if (err < 0)
return err;
} else {
err = skb_cow(skb, sizeof(hdr));
if (unlikely(err))
return err;
}
switch (lowpan_dev(dev)->lltype) {
case LOWPAN_LLTYPE_IEEE802154:
if (lowpan_802154_cb(skb)->d_size)
hdr.payload_len = htons(lowpan_802154_cb(skb)->d_size -
sizeof(struct ipv6hdr));
else
hdr.payload_len = htons(skb->len);
break;
default:
hdr.payload_len = htons(skb->len);
break;
}
pr_debug("skb headroom size = %d, data length = %d\n",
skb_headroom(skb), skb->len);
pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength = %d\n\t"
"nexthdr = 0x%02x\n\thop_lim = %d\n\tdest = %pI6c\n",
hdr.version, ntohs(hdr.payload_len), hdr.nexthdr,
hdr.hop_limit, &hdr.daddr);
skb_push(skb, sizeof(hdr));
skb_reset_mac_header(skb);
skb_reset_network_header(skb);
skb_copy_to_linear_data(skb, &hdr, sizeof(hdr));
raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
return 0;
}
EXPORT_SYMBOL_GPL(lowpan_header_decompress);
static const u8 lowpan_iphc_dam_to_sam_value[] = {
[LOWPAN_IPHC_DAM_00] = LOWPAN_IPHC_SAM_00,
[LOWPAN_IPHC_DAM_01] = LOWPAN_IPHC_SAM_01,
[LOWPAN_IPHC_DAM_10] = LOWPAN_IPHC_SAM_10,
[LOWPAN_IPHC_DAM_11] = LOWPAN_IPHC_SAM_11,
};
static inline bool
lowpan_iphc_compress_ctx_802154_lladdr(const struct in6_addr *ipaddr,
const struct lowpan_iphc_ctx *ctx,
const void *lladdr)
{
const struct ieee802154_addr *addr = lladdr;
unsigned char extended_addr[EUI64_ADDR_LEN];
bool lladdr_compress = false;
struct in6_addr tmp = {};
switch (addr->mode) {
case IEEE802154_ADDR_LONG:
ieee802154_le64_to_be64(&extended_addr, &addr->extended_addr);
/* check for SAM/DAM = 11 */
memcpy(&tmp.s6_addr[8], &extended_addr, EUI64_ADDR_LEN);
/* second bit-flip (Universe/Local) is done according RFC2464 */
tmp.s6_addr[8] ^= 0x02;
/* context information are always used */
ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
if (ipv6_addr_equal(&tmp, ipaddr))
lladdr_compress = true;
break;
case IEEE802154_ADDR_SHORT:
tmp.s6_addr[11] = 0xFF;
tmp.s6_addr[12] = 0xFE;
ieee802154_le16_to_be16(&tmp.s6_addr16[7],
&addr->short_addr);
/* context information are always used */
ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
if (ipv6_addr_equal(&tmp, ipaddr))
lladdr_compress = true;
break;
default:
/* should never handled and filtered by 802154 6lowpan */
WARN_ON_ONCE(1);
break;
}
return lladdr_compress;
}
static bool lowpan_iphc_addr_equal(const struct net_device *dev,
const struct lowpan_iphc_ctx *ctx,
const struct in6_addr *ipaddr,
const void *lladdr)
{
struct in6_addr tmp = {};
lowpan_iphc_uncompress_lladdr(dev, &tmp, lladdr);
if (ctx)
ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
return ipv6_addr_equal(&tmp, ipaddr);
}
static u8 lowpan_compress_ctx_addr(u8 **hc_ptr, const struct net_device *dev,
const struct in6_addr *ipaddr,
const struct lowpan_iphc_ctx *ctx,
const unsigned char *lladdr, bool sam)
{
struct in6_addr tmp = {};
u8 dam;
switch (lowpan_dev(dev)->lltype) {
case LOWPAN_LLTYPE_IEEE802154:
if (lowpan_iphc_compress_ctx_802154_lladdr(ipaddr, ctx,
lladdr)) {
dam = LOWPAN_IPHC_DAM_11;
goto out;
}
break;
default:
if (lowpan_iphc_addr_equal(dev, ctx, ipaddr, lladdr)) {
dam = LOWPAN_IPHC_DAM_11;
goto out;
}
break;
}
memset(&tmp, 0, sizeof(tmp));
/* check for SAM/DAM = 10 */
tmp.s6_addr[11] = 0xFF;
tmp.s6_addr[12] = 0xFE;
memcpy(&tmp.s6_addr[14], &ipaddr->s6_addr[14], 2);
/* context information are always used */
ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
if (ipv6_addr_equal(&tmp, ipaddr)) {
lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[14], 2);
dam = LOWPAN_IPHC_DAM_10;
goto out;
}
memset(&tmp, 0, sizeof(tmp));
/* check for SAM/DAM = 01, should always match */
memcpy(&tmp.s6_addr[8], &ipaddr->s6_addr[8], 8);
/* context information are always used */
ipv6_addr_prefix_copy(&tmp, &ctx->pfx, ctx->plen);
if (ipv6_addr_equal(&tmp, ipaddr)) {
lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[8], 8);
dam = LOWPAN_IPHC_DAM_01;
goto out;
}
WARN_ONCE(1, "context found but no address mode matched\n");
return LOWPAN_IPHC_DAM_00;
out:
if (sam)
return lowpan_iphc_dam_to_sam_value[dam];
else
return dam;
}
static inline bool
lowpan_iphc_compress_802154_lladdr(const struct in6_addr *ipaddr,
const void *lladdr)
{
const struct ieee802154_addr *addr = lladdr;
unsigned char extended_addr[EUI64_ADDR_LEN];
bool lladdr_compress = false;
struct in6_addr tmp = {};
switch (addr->mode) {
case IEEE802154_ADDR_LONG:
ieee802154_le64_to_be64(&extended_addr, &addr->extended_addr);
if (is_addr_mac_addr_based(ipaddr, extended_addr))
lladdr_compress = true;
break;
case IEEE802154_ADDR_SHORT:
/* fe:80::ff:fe00:XXXX
* \__/
* short_addr
*
* Universe/Local bit is zero.
*/
tmp.s6_addr[0] = 0xFE;
tmp.s6_addr[1] = 0x80;
tmp.s6_addr[11] = 0xFF;
tmp.s6_addr[12] = 0xFE;
ieee802154_le16_to_be16(&tmp.s6_addr16[7],
&addr->short_addr);
if (ipv6_addr_equal(&tmp, ipaddr))
lladdr_compress = true;
break;
default:
/* should never handled and filtered by 802154 6lowpan */
WARN_ON_ONCE(1);
break;
}
return lladdr_compress;
}
static u8 lowpan_compress_addr_64(u8 **hc_ptr, const struct net_device *dev,
const struct in6_addr *ipaddr,
const unsigned char *lladdr, bool sam)
{
u8 dam = LOWPAN_IPHC_DAM_01;
switch (lowpan_dev(dev)->lltype) {
case LOWPAN_LLTYPE_IEEE802154:
if (lowpan_iphc_compress_802154_lladdr(ipaddr, lladdr)) {
dam = LOWPAN_IPHC_DAM_11; /* 0-bits */
pr_debug("address compression 0 bits\n");
goto out;
}
break;
default:
if (lowpan_iphc_addr_equal(dev, NULL, ipaddr, lladdr)) {
dam = LOWPAN_IPHC_DAM_11;
pr_debug("address compression 0 bits\n");
goto out;
}
break;
}
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);
dam = LOWPAN_IPHC_DAM_10; /* 16-bits */
raw_dump_inline(NULL, "Compressed ipv6 addr is (16 bits)",
*hc_ptr - 2, 2);
goto out;
}
/* do not compress IID => xxxx::IID */
lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr16[4], 8);
raw_dump_inline(NULL, "Compressed ipv6 addr is (64 bits)",
*hc_ptr - 8, 8);
out:
if (sam)
return lowpan_iphc_dam_to_sam_value[dam];
else
return dam;
}
/* lowpan_iphc_get_tc - get the ECN + DCSP fields in hc format */
static inline u8 lowpan_iphc_get_tc(const struct ipv6hdr *hdr)
{
u8 dscp, ecn;
/* hdr->priority contains the higher bits of dscp, lower are part of
* flow_lbl[0]. Note ECN, DCSP is swapped in ipv6 hdr.
*/
dscp = (hdr->priority << 2) | ((hdr->flow_lbl[0] & 0xc0) >> 6);
/* ECN is at the two lower bits from first nibble of flow_lbl[0] */
ecn = (hdr->flow_lbl[0] & 0x30);
/* for pretty debug output, also shift ecn to get the ecn value */
pr_debug("ecn 0x%02x dscp 0x%02x\n", ecn >> 4, dscp);
/* ECN is at 0x30 now, shift it to have ECN + DCSP */
return (ecn << 2) | dscp;
}
/* lowpan_iphc_is_flow_lbl_zero - check if flow label is zero */
static inline bool lowpan_iphc_is_flow_lbl_zero(const struct ipv6hdr *hdr)
{
return ((!(hdr->flow_lbl[0] & 0x0f)) &&
!hdr->flow_lbl[1] && !hdr->flow_lbl[2]);
}
/* lowpan_iphc_tf_compress - compress the traffic class which is set by
* ipv6hdr. Return the corresponding format identifier which is used.
*/
static u8 lowpan_iphc_tf_compress(u8 **hc_ptr, const struct ipv6hdr *hdr)
{
/* get ecn dscp data in a byteformat as: ECN(hi) + DSCP(lo) */
u8 tc = lowpan_iphc_get_tc(hdr), tf[4], val;
/* printout the traffic class in hc format */
pr_debug("tc 0x%02x\n", tc);
if (lowpan_iphc_is_flow_lbl_zero(hdr)) {
if (!tc) {
/* 11: Traffic Class and Flow Label are elided. */
val = LOWPAN_IPHC_TF_11;
} else {
/* 10: ECN + DSCP (1 byte), Flow Label is elided.
*
* 0 1 2 3 4 5 6 7
* +-+-+-+-+-+-+-+-+
* |ECN| DSCP |
* +-+-+-+-+-+-+-+-+
*/
lowpan_push_hc_data(hc_ptr, &tc, sizeof(tc));
val = LOWPAN_IPHC_TF_10;
}
} else {
/* check if dscp is zero, it's after the first two bit */
if (!(tc & 0x3f)) {
/* 01: ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
*
* 1 2
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |ECN|rsv| Flow Label |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
memcpy(&tf[0], &hdr->flow_lbl[0], 3);
/* zero the highest 4-bits, contains DCSP + ECN */
tf[0] &= ~0xf0;
/* set ECN */
tf[0] |= (tc & 0xc0);
lowpan_push_hc_data(hc_ptr, tf, 3);
val = LOWPAN_IPHC_TF_01;
} else {
/* 00: ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
*
* 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |ECN| DSCP | rsv | Flow Label |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
memcpy(&tf[0], &tc, sizeof(tc));
/* highest nibble of flow_lbl[0] is part of DSCP + ECN
* which will be the 4-bit pad and will be filled with
* zeros afterwards.
*/
memcpy(&tf[1], &hdr->flow_lbl[0], 3);
/* zero the 4-bit pad, which is reserved */
tf[1] &= ~0xf0;
lowpan_push_hc_data(hc_ptr, tf, 4);
val = LOWPAN_IPHC_TF_00;
}
}
return val;
}
static u8 lowpan_iphc_mcast_ctx_addr_compress(u8 **hc_ptr,
const struct lowpan_iphc_ctx *ctx,
const struct in6_addr *ipaddr)
{
u8 data[6];
/* flags/scope, reserved (RIID) */
memcpy(data, &ipaddr->s6_addr[1], 2);
/* group ID */
memcpy(&data[1], &ipaddr->s6_addr[11], 4);
lowpan_push_hc_data(hc_ptr, data, 6);
return LOWPAN_IPHC_DAM_00;
}
static u8 lowpan_iphc_mcast_addr_compress(u8 **hc_ptr,
const struct in6_addr *ipaddr)
{
u8 val;
if (lowpan_is_mcast_addr_compressable8(ipaddr)) {
pr_debug("compressed to 1 octet\n");
/* use last byte */
lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[15], 1);
val = LOWPAN_IPHC_DAM_11;
} else if (lowpan_is_mcast_addr_compressable32(ipaddr)) {
pr_debug("compressed to 4 octets\n");
/* second byte + the last three */
lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[13], 3);
val = LOWPAN_IPHC_DAM_10;
} else if (lowpan_is_mcast_addr_compressable48(ipaddr)) {
pr_debug("compressed to 6 octets\n");
/* second byte + the last five */
lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[1], 1);
lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[11], 5);
val = LOWPAN_IPHC_DAM_01;
} else {
pr_debug("using full address\n");
lowpan_push_hc_data(hc_ptr, ipaddr->s6_addr, 16);
val = LOWPAN_IPHC_DAM_00;
}
return val;
}
int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
const void *daddr, const void *saddr)
{
u8 iphc0, iphc1, *hc_ptr, cid = 0;
struct ipv6hdr *hdr;
u8 head[LOWPAN_IPHC_MAX_HC_BUF_LEN] = {};
struct lowpan_iphc_ctx *dci, *sci, dci_entry, sci_entry;
int ret, ipv6_daddr_type, ipv6_saddr_type;
if (skb->protocol != htons(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;
raw_dump_table(__func__, "sending raw skb network uncompressed packet",
skb->data, skb->len);
ipv6_daddr_type = ipv6_addr_type(&hdr->daddr);
spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
if (ipv6_daddr_type & IPV6_ADDR_MULTICAST)
dci = lowpan_iphc_ctx_get_by_mcast_addr(dev, &hdr->daddr);
else
dci = lowpan_iphc_ctx_get_by_addr(dev, &hdr->daddr);
if (dci) {
memcpy(&dci_entry, dci, sizeof(*dci));
cid |= dci->id;
}
spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
spin_lock_bh(&lowpan_dev(dev)->ctx.lock);
sci = lowpan_iphc_ctx_get_by_addr(dev, &hdr->saddr);
if (sci) {
memcpy(&sci_entry, sci, sizeof(*sci));
cid |= (sci->id << 4);
}
spin_unlock_bh(&lowpan_dev(dev)->ctx.lock);
/* if cid is zero it will be compressed */
if (cid) {
iphc1 |= LOWPAN_IPHC_CID;
lowpan_push_hc_data(&hc_ptr, &cid, sizeof(cid));
}
/* Traffic Class, Flow Label compression */
iphc0 |= lowpan_iphc_tf_compress(&hc_ptr, hdr);
/* NOTE: payload length is always compressed */
/* Check if we provide the nhc format for nexthdr and compression
* functionality. If not nexthdr is handled inline and not compressed.
*/
ret = lowpan_nhc_check_compression(skb, hdr, &hc_ptr);
if (ret == -ENOENT)
lowpan_push_hc_data(&hc_ptr, &hdr->nexthdr,
sizeof(hdr->nexthdr));
else
iphc0 |= LOWPAN_IPHC_NH;
/* 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_HLIM_01;
break;
case 64:
iphc0 |= LOWPAN_IPHC_HLIM_10;
break;
case 255:
iphc0 |= LOWPAN_IPHC_HLIM_11;
break;
default:
lowpan_push_hc_data(&hc_ptr, &hdr->hop_limit,
sizeof(hdr->hop_limit));
}
ipv6_saddr_type = ipv6_addr_type(&hdr->saddr);
/* source address compression */
if (ipv6_saddr_type == IPV6_ADDR_ANY) {
pr_debug("source address is unspecified, setting SAC\n");
iphc1 |= LOWPAN_IPHC_SAC;
} else {
if (sci) {
iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, dev,
&hdr->saddr,
&sci_entry, saddr,
true);
iphc1 |= LOWPAN_IPHC_SAC;
} else {
if (ipv6_saddr_type & IPV6_ADDR_LINKLOCAL &&
lowpan_is_linklocal_zero_padded(hdr->saddr)) {
iphc1 |= lowpan_compress_addr_64(&hc_ptr, dev,
&hdr->saddr,
saddr, true);
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);
}
}
}
/* destination address compression */
if (ipv6_daddr_type & IPV6_ADDR_MULTICAST) {
pr_debug("destination address is multicast: ");
iphc1 |= LOWPAN_IPHC_M;
if (dci) {
iphc1 |= lowpan_iphc_mcast_ctx_addr_compress(&hc_ptr,
&dci_entry,
&hdr->daddr);
iphc1 |= LOWPAN_IPHC_DAC;
} else {
iphc1 |= lowpan_iphc_mcast_addr_compress(&hc_ptr,
&hdr->daddr);
}
} else {
if (dci) {
iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, dev,
&hdr->daddr,
&dci_entry, daddr,
false);
iphc1 |= LOWPAN_IPHC_DAC;
} else {
if (ipv6_daddr_type & IPV6_ADDR_LINKLOCAL &&
lowpan_is_linklocal_zero_padded(hdr->daddr)) {
iphc1 |= lowpan_compress_addr_64(&hc_ptr, dev,
&hdr->daddr,
daddr, false);
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);
}
}
}
/* next header compression */
if (iphc0 & LOWPAN_IPHC_NH) {
ret = lowpan_nhc_do_compression(skb, hdr, &hc_ptr);
if (ret < 0)
return ret;
}
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);
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