kernel-ark/net/6lowpan/iphc.c
Alexander Aring ff0fcc2987 6lowpan: nhc: add other known rfc6282 compressions
This patch adds other known rfc6282 compression formats to the nhc
framework. These compression formats are known but not implemented yet.
For now this is useful to printout a warning which compression format
isn't supported.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Cc: Martin Townsend <mtownsend1973@gmail.com>
Reviewed-by: Stefan Schmidt <s.schmidt@samsung.com>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2015-02-14 23:08:44 +01:00

629 lines
18 KiB
C

/*
* 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/module.h>
#include <linux/netdevice.h>
#include <net/6lowpan.h>
#include <net/ipv6.h>
#include <net/af_ieee802154.h>
#include "nhc.h"
/* Uncompress address function for source and
* destination address(non-multicast).
*
* address_mode is sam value or dam value.
*/
static int uncompress_addr(struct sk_buff *skb,
struct in6_addr *ipaddr, const u8 address_mode,
const u8 *lladdr, const u8 addr_type,
const u8 addr_len)
{
bool fail;
switch (address_mode) {
case LOWPAN_IPHC_ADDR_00:
/* for global link addresses */
fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
break;
case LOWPAN_IPHC_ADDR_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_ADDR_02:
/* 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_ADDR_03:
fail = false;
switch (addr_type) {
case IEEE802154_ADDR_LONG:
/* fe:80::XXXX:XXXX:XXXX:XXXX
* \_________________/
* hwaddr
*/
ipaddr->s6_addr[0] = 0xFE;
ipaddr->s6_addr[1] = 0x80;
memcpy(&ipaddr->s6_addr[8], lladdr, addr_len);
/* second bit-flip (Universe/Local)
* is done according RFC2464
*/
ipaddr->s6_addr[8] ^= 0x02;
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;
ipaddr->s6_addr16[7] = htons(*((u16 *)lladdr));
break;
default:
pr_debug("Invalid addr_type set\n");
return -EINVAL;
}
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 uncompress_context_based_src_addr(struct sk_buff *skb,
struct in6_addr *ipaddr,
const u8 sam)
{
switch (sam) {
case LOWPAN_IPHC_ADDR_00:
/* unspec address ::
* Do nothing, address is already ::
*/
break;
case LOWPAN_IPHC_ADDR_01:
/* TODO */
case LOWPAN_IPHC_ADDR_02:
/* TODO */
case LOWPAN_IPHC_ADDR_03:
/* TODO */
netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
return -EINVAL;
default:
pr_debug("Invalid sam value: 0x%x\n", sam);
return -EINVAL;
}
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,
const u8 dam)
{
bool fail;
switch (dam) {
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", dam);
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;
}
/* TTL uncompression values */
static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
int
lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
const u8 *saddr, const u8 saddr_type,
const u8 saddr_len, const u8 *daddr,
const u8 daddr_type, const u8 daddr_len,
u8 iphc0, u8 iphc1)
{
struct ipv6hdr hdr = {};
u8 tmp, num_context = 0;
int err;
raw_dump_table(__func__, "raw skb data dump uncompressed",
skb->data, skb->len);
/* another if the CID flag is set */
if (iphc1 & LOWPAN_IPHC_CID) {
pr_debug("CID flag is set, increase header with one\n");
if (lowpan_fetch_skb(skb, &num_context, sizeof(num_context)))
return -EINVAL;
}
hdr.version = 6;
/* Traffic Class and Flow Label */
switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
/* Traffic Class and FLow Label carried in-line
* ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
*/
case 0: /* 00b */
if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
return -EINVAL;
memcpy(&hdr.flow_lbl, &skb->data[0], 3);
skb_pull(skb, 3);
hdr.priority = ((tmp >> 2) & 0x0f);
hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) |
(hdr.flow_lbl[0] & 0x0f);
break;
/* Traffic class carried in-line
* ECN + DSCP (1 byte), Flow Label is elided
*/
case 2: /* 10b */
if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
return -EINVAL;
hdr.priority = ((tmp >> 2) & 0x0f);
hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
break;
/* Flow Label carried in-line
* ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
*/
case 1: /* 01b */
if (lowpan_fetch_skb(skb, &tmp, sizeof(tmp)))
return -EINVAL;
hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30);
memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
skb_pull(skb, 2);
break;
/* Traffic Class and Flow Label are elided */
case 3: /* 11b */
break;
default:
break;
}
/* Next Header */
if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
/* 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 & 0x03) != LOWPAN_IPHC_TTL_I) {
hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];
} else {
if (lowpan_fetch_skb(skb, &hdr.hop_limit,
sizeof(hdr.hop_limit)))
return -EINVAL;
}
/* Extract SAM to the tmp variable */
tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;
if (iphc1 & LOWPAN_IPHC_SAC) {
/* Source address context based uncompression */
pr_debug("SAC bit is set. Handle context based source address.\n");
err = uncompress_context_based_src_addr(skb, &hdr.saddr, tmp);
} else {
/* Source address uncompression */
pr_debug("source address stateless compression\n");
err = uncompress_addr(skb, &hdr.saddr, tmp, saddr,
saddr_type, saddr_len);
}
/* Check on error of previous branch */
if (err)
return -EINVAL;
/* Extract DAM to the tmp variable */
tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;
/* check for Multicast Compression */
if (iphc1 & LOWPAN_IPHC_M) {
if (iphc1 & LOWPAN_IPHC_DAC) {
pr_debug("dest: context-based mcast compression\n");
/* TODO: implement this */
} else {
err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
tmp);
if (err)
return -EINVAL;
}
} else {
err = uncompress_addr(skb, &hdr.daddr, tmp, daddr,
daddr_type, daddr_len);
pr_debug("dest: stateless compression mode %d dest %pI6c\n",
tmp, &hdr.daddr);
if (err)
return -EINVAL;
}
/* Next header data uncompression */
if (iphc0 & LOWPAN_IPHC_NH_C) {
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;
}
hdr.payload_len = htons(skb->len);
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_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 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);
}
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 ret, 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 */
/* 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, &iphc0);
if (ret < 0)
return ret;
/* 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);
}
}
/* next header compression */
if (iphc0 & LOWPAN_IPHC_NH_C) {
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);
static int __init lowpan_module_init(void)
{
request_module_nowait("nhc_dest");
request_module_nowait("nhc_fragment");
request_module_nowait("nhc_hop");
request_module_nowait("nhc_ipv6");
request_module_nowait("nhc_mobility");
request_module_nowait("nhc_routing");
request_module_nowait("nhc_udp");
return 0;
}
module_init(lowpan_module_init);
MODULE_LICENSE("GPL");