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lwip/src/netif/lowpan6_common.c
goldsimon a4b9beef04 Move common 6LoWPAN code to new file lopwan6_common.c 
This is mainly IPHC (de)compression.

TODO: adapt the 6LoWPAN-over-BLE netif to this.

Signed-off-by: goldsimon <goldsimon@gmx.de>
2018-03-21 20:55:05 +01:00

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/**
* @file
*
* Common 6LowPAN routines for IPv6. Uses ND tables for link-layer addressing. Fragments packets to 6LowPAN units.
*
* This implementation aims to conform to IEEE 802.15.4(-2015), RFC 4944 and RFC 6282.
* @todo: RFC 6775.
*/
/*
* Copyright (c) 2015 Inico Technologies Ltd.
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Ivan Delamer <delamer@inicotech.com>
*
*
* Please coordinate changes and requests with Ivan Delamer
* <delamer@inicotech.com>
*/
/**
* @defgroup sixlowpan 6LoWPAN (RFC4944)
* @ingroup netifs
* 6LowPAN netif implementation
*/
#include "netif/lowpan6_common.h"
#if LWIP_IPV6
#include "lwip/ip.h"
#include "lwip/pbuf.h"
#include "lwip/ip_addr.h"
#include "lwip/netif.h"
#include "lwip/udp.h"
#include <string.h>
/* Determine compression mode for unicast address. */
s8_t
lowpan6_get_address_mode(const ip6_addr_t *ip6addr, const struct lowpan6_link_addr *mac_addr)
{
if (mac_addr->addr_len == 2) {
if ((ip6addr->addr[2] == (u32_t)PP_HTONL(0x000000ff)) &&
((ip6addr->addr[3] & PP_HTONL(0xffff0000)) == PP_NTOHL(0xfe000000))) {
if ((ip6addr->addr[3] & PP_HTONL(0x0000ffff)) == lwip_ntohl((mac_addr->addr[0] << 8) | mac_addr->addr[1])) {
return 3;
}
}
} else if (mac_addr->addr_len == 8) {
if ((ip6addr->addr[2] == lwip_ntohl(((mac_addr->addr[0] ^ 2) << 24) | (mac_addr->addr[1] << 16) | mac_addr->addr[2] << 8 | mac_addr->addr[3])) &&
(ip6addr->addr[3] == lwip_ntohl((mac_addr->addr[4] << 24) | (mac_addr->addr[5] << 16) | mac_addr->addr[6] << 8 | mac_addr->addr[7]))) {
return 3;
}
}
if ((ip6addr->addr[2] == PP_HTONL(0x000000ffUL)) &&
((ip6addr->addr[3] & PP_HTONL(0xffff0000)) == PP_NTOHL(0xfe000000UL))) {
return 2;
}
return 1;
}
#if LWIP_6LOWPAN_IPHC
/* Determine compression mode for multicast address. */
static s8_t
lowpan6_get_address_mode_mc(const ip6_addr_t *ip6addr)
{
if ((ip6addr->addr[0] == PP_HTONL(0xff020000)) &&
(ip6addr->addr[1] == 0) &&
(ip6addr->addr[2] == 0) &&
((ip6addr->addr[3] & PP_HTONL(0xffffff00)) == 0)) {
return 3;
} else if (((ip6addr->addr[0] & PP_HTONL(0xff00ffff)) == PP_HTONL(0xff000000)) &&
(ip6addr->addr[1] == 0)) {
if ((ip6addr->addr[2] == 0) &&
((ip6addr->addr[3] & PP_HTONL(0xff000000)) == 0)) {
return 2;
} else if ((ip6addr->addr[2] & PP_HTONL(0xffffff00)) == 0) {
return 1;
}
}
return 0;
}
#if LWIP_6LOWPAN_NUM_CONTEXTS > 0
static s8_t
lowpan6_context_lookup(const ip6_addr_t *lowpan6_contexts, const ip6_addr_t *ip6addr)
{
s8_t i;
for (i = 0; i < LWIP_6LOWPAN_NUM_CONTEXTS; i++) {
if (ip6_addr_netcmp(&lowpan6_contexts[i], ip6addr)) {
return i;
}
}
return -1;
}
#endif /* LWIP_6LOWPAN_NUM_CONTEXTS > 0 */
/*
* Compress IPv6 and/or UDP headers.
* */
err_t
lowpan6_compress_headers(struct netif *netif, u8_t *inbuf, size_t inbuf_size, u8_t *outbuf, size_t outbuf_size,
u8_t *lowpan6_header_len_out, u8_t *hidden_header_len_out, ip6_addr_t *lowpan6_contexts,
const struct lowpan6_link_addr *src, const struct lowpan6_link_addr *dst)
{
u8_t *buffer, *inptr;
u8_t lowpan6_header_len;
u8_t hidden_header_len = 0;
s8_t i;
struct ip6_hdr *ip6hdr;
ip_addr_t ip6src, ip6dst;
LWIP_ASSERT("netif != NULL", netif != NULL);
LWIP_ASSERT("inbuf != NULL", inbuf != NULL);
LWIP_ASSERT("outbuf != NULL", outbuf != NULL);
LWIP_ASSERT("lowpan6_header_len_out != NULL", lowpan6_header_len_out != NULL);
LWIP_ASSERT("hidden_header_len_out != NULL", hidden_header_len_out != NULL);
/* Perform 6LowPAN IPv6 header compression according to RFC 6282 */
buffer = outbuf;
inptr = inbuf;
if (inbuf_size < IP6_HLEN) {
/* input buffer too short */
return ERR_VAL;
}
if (outbuf_size < IP6_HLEN) {
/* output buffer too short for worst case */
return ERR_MEM;
}
/* Point to ip6 header and align copies of src/dest addresses. */
ip6hdr = (struct ip6_hdr *)inptr;
ip_addr_copy_from_ip6_packed(ip6dst, ip6hdr->dest);
ip6_addr_assign_zone(ip_2_ip6(&ip6dst), IP6_UNKNOWN, netif);
ip_addr_copy_from_ip6_packed(ip6src, ip6hdr->src);
ip6_addr_assign_zone(ip_2_ip6(&ip6src), IP6_UNKNOWN, netif);
/* Basic length of 6LowPAN header, set dispatch and clear fields. */
lowpan6_header_len = 2;
buffer[0] = 0x60;
buffer[1] = 0;
/* Determine whether there will be a Context Identifier Extension byte or not.
* If so, set it already. */
#if LWIP_6LOWPAN_NUM_CONTEXTS > 0
buffer[2] = 0;
i = lowpan6_context_lookup(lowpan6_contexts, ip_2_ip6(&ip6src));
if (i >= 0) {
/* Stateful source address compression. */
buffer[1] |= 0x40;
buffer[2] |= (i & 0x0f) << 4;
}
i = lowpan6_context_lookup(lowpan6_contexts, ip_2_ip6(&ip6dst));
if (i >= 0) {
/* Stateful destination address compression. */
buffer[1] |= 0x04;
buffer[2] |= i & 0x0f;
}
if (buffer[2] != 0x00) {
/* Context identifier extension byte is appended. */
buffer[1] |= 0x80;
lowpan6_header_len++;
}
#else /* LWIP_6LOWPAN_NUM_CONTEXTS > 0 */
LWIP_UNUSED_ARG(lowpan6_contexts);
#endif /* LWIP_6LOWPAN_NUM_CONTEXTS > 0 */
/* Determine TF field: Traffic Class, Flow Label */
if (IP6H_FL(ip6hdr) == 0) {
/* Flow label is elided. */
buffer[0] |= 0x10;
if (IP6H_TC(ip6hdr) == 0) {
/* Traffic class (ECN+DSCP) elided too. */
buffer[0] |= 0x08;
} else {
/* Traffic class (ECN+DSCP) appended. */
buffer[lowpan6_header_len++] = IP6H_TC(ip6hdr);
}
} else {
if (((IP6H_TC(ip6hdr) & 0x3f) == 0)) {
/* DSCP portion of Traffic Class is elided, ECN and FL are appended (3 bytes) */
buffer[0] |= 0x08;
buffer[lowpan6_header_len] = IP6H_TC(ip6hdr) & 0xc0;
buffer[lowpan6_header_len++] |= (IP6H_FL(ip6hdr) >> 16) & 0x0f;
buffer[lowpan6_header_len++] = (IP6H_FL(ip6hdr) >> 8) & 0xff;
buffer[lowpan6_header_len++] = IP6H_FL(ip6hdr) & 0xff;
} else {
/* Traffic class and flow label are appended (4 bytes) */
buffer[lowpan6_header_len++] = IP6H_TC(ip6hdr);
buffer[lowpan6_header_len++] = (IP6H_FL(ip6hdr) >> 16) & 0x0f;
buffer[lowpan6_header_len++] = (IP6H_FL(ip6hdr) >> 8) & 0xff;
buffer[lowpan6_header_len++] = IP6H_FL(ip6hdr) & 0xff;
}
}
/* Compress NH?
* Only if UDP for now. @todo support other NH compression. */
if (IP6H_NEXTH(ip6hdr) == IP6_NEXTH_UDP) {
buffer[0] |= 0x04;
} else {
/* append nexth. */
buffer[lowpan6_header_len++] = IP6H_NEXTH(ip6hdr);
}
/* Compress hop limit? */
if (IP6H_HOPLIM(ip6hdr) == 255) {
buffer[0] |= 0x03;
} else if (IP6H_HOPLIM(ip6hdr) == 64) {
buffer[0] |= 0x02;
} else if (IP6H_HOPLIM(ip6hdr) == 1) {
buffer[0] |= 0x01;
} else {
/* append hop limit */
buffer[lowpan6_header_len++] = IP6H_HOPLIM(ip6hdr);
}
/* Compress source address */
if (((buffer[1] & 0x40) != 0) ||
(ip6_addr_islinklocal(ip_2_ip6(&ip6src)))) {
/* Context-based or link-local source address compression. */
i = lowpan6_get_address_mode(ip_2_ip6(&ip6src), src);
buffer[1] |= (i & 0x03) << 4;
if (i == 1) {
MEMCPY(buffer + lowpan6_header_len, inptr + 16, 8);
lowpan6_header_len += 8;
} else if (i == 2) {
MEMCPY(buffer + lowpan6_header_len, inptr + 22, 2);
lowpan6_header_len += 2;
}
} else if (ip6_addr_isany(ip_2_ip6(&ip6src))) {
/* Special case: mark SAC and leave SAM=0 */
buffer[1] |= 0x40;
} else {
/* Append full address. */
MEMCPY(buffer + lowpan6_header_len, inptr + 8, 16);
lowpan6_header_len += 16;
}
/* Compress destination address */
if (ip6_addr_ismulticast(ip_2_ip6(&ip6dst))) {
/* @todo support stateful multicast address compression */
buffer[1] |= 0x08;
i = lowpan6_get_address_mode_mc(ip_2_ip6(&ip6dst));
buffer[1] |= i & 0x03;
if (i == 0) {
MEMCPY(buffer + lowpan6_header_len, inptr + 24, 16);
lowpan6_header_len += 16;
} else if (i == 1) {
buffer[lowpan6_header_len++] = inptr[25];
MEMCPY(buffer + lowpan6_header_len, inptr + 35, 5);
lowpan6_header_len += 5;
} else if (i == 2) {
buffer[lowpan6_header_len++] = inptr[25];
MEMCPY(buffer + lowpan6_header_len, inptr + 37, 3);
lowpan6_header_len += 3;
} else if (i == 3) {
buffer[lowpan6_header_len++] = (inptr)[39];
}
} else if (((buffer[1] & 0x04) != 0) ||
(ip6_addr_islinklocal(ip_2_ip6(&ip6dst)))) {
/* Context-based or link-local destination address compression. */
i = lowpan6_get_address_mode(ip_2_ip6(&ip6dst), dst);
buffer[1] |= i & 0x03;
if (i == 1) {
MEMCPY(buffer + lowpan6_header_len, inptr + 32, 8);
lowpan6_header_len += 8;
} else if (i == 2) {
MEMCPY(buffer + lowpan6_header_len, inptr + 38, 2);
lowpan6_header_len += 2;
}
} else {
/* Append full address. */
MEMCPY(buffer + lowpan6_header_len, inptr + 24, 16);
lowpan6_header_len += 16;
}
/* Move to payload. */
inptr += IP6_HLEN;
hidden_header_len += IP6_HLEN;
#if LWIP_UDP
/* Compress UDP header? */
if (IP6H_NEXTH(ip6hdr) == IP6_NEXTH_UDP) {
/* @todo support optional checksum compression */
if (inbuf_size < IP6_HLEN + UDP_HLEN) {
/* input buffer too short */
return ERR_VAL;
}
if (outbuf_size < (size_t)(hidden_header_len + 7)) {
/* output buffer too short for worst case */
return ERR_MEM;
}
buffer[lowpan6_header_len] = 0xf0;
/* determine port compression mode. */
if ((inptr[0] == 0xf0) && ((inptr[1] & 0xf0) == 0xb0) &&
(inptr[2] == 0xf0) && ((inptr[3] & 0xf0) == 0xb0)) {
/* Compress source and dest ports. */
buffer[lowpan6_header_len++] |= 0x03;
buffer[lowpan6_header_len++] = ((inptr[1] & 0x0f) << 4) | (inptr[3] & 0x0f);
} else if (inptr[0] == 0xf0) {
/* Compress source port. */
buffer[lowpan6_header_len++] |= 0x02;
buffer[lowpan6_header_len++] = inptr[1];
buffer[lowpan6_header_len++] = inptr[2];
buffer[lowpan6_header_len++] = inptr[3];
} else if (inptr[2] == 0xf0) {
/* Compress dest port. */
buffer[lowpan6_header_len++] |= 0x01;
buffer[lowpan6_header_len++] = inptr[0];
buffer[lowpan6_header_len++] = inptr[1];
buffer[lowpan6_header_len++] = inptr[3];
} else {
/* append full ports. */
lowpan6_header_len++;
buffer[lowpan6_header_len++] = inptr[0];
buffer[lowpan6_header_len++] = inptr[1];
buffer[lowpan6_header_len++] = inptr[2];
buffer[lowpan6_header_len++] = inptr[3];
}
/* elide length and copy checksum */
buffer[lowpan6_header_len++] = inptr[6];
buffer[lowpan6_header_len++] = inptr[7];
hidden_header_len += UDP_HLEN;
}
#endif /* LWIP_UDP */
*lowpan6_header_len_out = lowpan6_header_len;
*hidden_header_len_out = hidden_header_len;
return ERR_OK;
}
/** Decompress IPv6 and UDP headers compressed according to RFC 6282
*
* @param lowpan6_buffer compressed headers, first byte is the dispatch byte
* @param lowpan6_bufsize size of lowpan6_buffer (may include data after headers)
* @param decomp_buffer buffer where the decompressed headers are stored
* @param decomp_bufsize size of decomp_buffer
* @param hdr_size_comp returns the size of the compressed headers (skip to get to data)
* @param hdr_size_decomp returns the size of the decompressed headers (IPv6 + UDP)
* @param datagram_size datagram size from fragments or 0 if unfragmented
* @param compressed_size compressed datagram size (for unfragmented rx)
* @param lowpan6_contexts context addresses
* @param src source address of the outer layer, used for address compression
* @param dest destination address of the outer layer, used for address compression
* @return ERR_OK if decompression succeeded, an error otherwise
*/
static err_t
lowpan6_decompress_hdr(u8_t *lowpan6_buffer, size_t lowpan6_bufsize,
u8_t *decomp_buffer, size_t decomp_bufsize,
u16_t *hdr_size_comp, u16_t *hdr_size_decomp,
u16_t datagram_size, u16_t compressed_size,
ip6_addr_t *lowpan6_contexts,
struct lowpan6_link_addr *src, struct lowpan6_link_addr *dest)
{
u16_t lowpan6_offset;
struct ip6_hdr *ip6hdr;
s8_t i;
u16_t ip6_offset = IP6_HLEN;
LWIP_ASSERT("lowpan6_buffer != NULL", lowpan6_buffer != NULL);
LWIP_ASSERT("decomp_buffer != NULL", decomp_buffer != NULL);
LWIP_ASSERT("src != NULL", src != NULL);
LWIP_ASSERT("dest != NULL", dest != NULL);
LWIP_ASSERT("hdr_size_comp != NULL", hdr_size_comp != NULL);
LWIP_ASSERT("dehdr_size_decompst != NULL", hdr_size_decomp != NULL);
ip6hdr = (struct ip6_hdr *)decomp_buffer;
if (decomp_bufsize < IP6_HLEN) {
return ERR_MEM;
}
lowpan6_offset = 2;
if (lowpan6_buffer[1] & 0x80) {
lowpan6_offset++;
}
/* Set IPv6 version, traffic class and flow label. */
if ((lowpan6_buffer[0] & 0x18) == 0x00) {
IP6H_VTCFL_SET(ip6hdr, 6, lowpan6_buffer[lowpan6_offset], ((lowpan6_buffer[lowpan6_offset + 1] & 0x0f) << 16) | (lowpan6_buffer[lowpan6_offset + 2] << 8) | lowpan6_buffer[lowpan6_offset + 3]);
lowpan6_offset += 4;
} else if ((lowpan6_buffer[0] & 0x18) == 0x08) {
IP6H_VTCFL_SET(ip6hdr, 6, lowpan6_buffer[lowpan6_offset] & 0xc0, ((lowpan6_buffer[lowpan6_offset] & 0x0f) << 16) | (lowpan6_buffer[lowpan6_offset + 1] << 8) | lowpan6_buffer[lowpan6_offset + 2]);
lowpan6_offset += 3;
} else if ((lowpan6_buffer[0] & 0x18) == 0x10) {
IP6H_VTCFL_SET(ip6hdr, 6, lowpan6_buffer[lowpan6_offset], 0);
lowpan6_offset += 1;
} else if ((lowpan6_buffer[0] & 0x18) == 0x18) {
IP6H_VTCFL_SET(ip6hdr, 6, 0, 0);
}
/* Set Next Header */
if ((lowpan6_buffer[0] & 0x04) == 0x00) {
IP6H_NEXTH_SET(ip6hdr, lowpan6_buffer[lowpan6_offset++]);
} else {
/* We should fill this later with NHC decoding */
IP6H_NEXTH_SET(ip6hdr, 0);
}
/* Set Hop Limit */
if ((lowpan6_buffer[0] & 0x03) == 0x00) {
IP6H_HOPLIM_SET(ip6hdr, lowpan6_buffer[lowpan6_offset++]);
} else if ((lowpan6_buffer[0] & 0x03) == 0x01) {
IP6H_HOPLIM_SET(ip6hdr, 1);
} else if ((lowpan6_buffer[0] & 0x03) == 0x02) {
IP6H_HOPLIM_SET(ip6hdr, 64);
} else if ((lowpan6_buffer[0] & 0x03) == 0x03) {
IP6H_HOPLIM_SET(ip6hdr, 255);
}
/* Source address decoding. */
if ((lowpan6_buffer[1] & 0x40) == 0x00) {
/* Stateless compression */
if ((lowpan6_buffer[1] & 0x30) == 0x00) {
/* copy full address */
MEMCPY(&ip6hdr->src.addr[0], lowpan6_buffer + lowpan6_offset, 16);
lowpan6_offset += 16;
} else if ((lowpan6_buffer[1] & 0x30) == 0x10) {
ip6hdr->src.addr[0] = PP_HTONL(0xfe800000UL);
ip6hdr->src.addr[1] = 0;
MEMCPY(&ip6hdr->src.addr[2], lowpan6_buffer + lowpan6_offset, 8);
lowpan6_offset += 8;
} else if ((lowpan6_buffer[1] & 0x30) == 0x20) {
ip6hdr->src.addr[0] = PP_HTONL(0xfe800000UL);
ip6hdr->src.addr[1] = 0;
ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL);
ip6hdr->src.addr[3] = lwip_htonl(0xfe000000UL | (lowpan6_buffer[lowpan6_offset] << 8) |
lowpan6_buffer[lowpan6_offset + 1]);
lowpan6_offset += 2;
} else if ((lowpan6_buffer[1] & 0x30) == 0x30) {
ip6hdr->src.addr[0] = PP_HTONL(0xfe800000UL);
ip6hdr->src.addr[1] = 0;
if (src->addr_len == 2) {
ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL);
ip6hdr->src.addr[3] = lwip_htonl(0xfe000000UL | (src->addr[0] << 8) | src->addr[1]);
} else {
ip6hdr->src.addr[2] = lwip_htonl(((src->addr[0] ^ 2) << 24) | (src->addr[1] << 16) |
(src->addr[2] << 8) | src->addr[3]);
ip6hdr->src.addr[3] = lwip_htonl((src->addr[4] << 24) | (src->addr[5] << 16) |
(src->addr[6] << 8) | src->addr[7]);
}
}
} else {
/* Stateful compression */
if ((lowpan6_buffer[1] & 0x30) == 0x00) {
/* ANY address */
ip6hdr->src.addr[0] = 0;
ip6hdr->src.addr[1] = 0;
ip6hdr->src.addr[2] = 0;
ip6hdr->src.addr[3] = 0;
} else {
/* Set prefix from context info */
if (lowpan6_buffer[1] & 0x80) {
i = (lowpan6_buffer[2] >> 4) & 0x0f;
} else {
i = 0;
}
if (i >= LWIP_6LOWPAN_NUM_CONTEXTS) {
/* Error */
return ERR_VAL;
}
#if LWIP_6LOWPAN_NUM_CONTEXTS > 0
ip6hdr->src.addr[0] = lowpan6_contexts[i].addr[0];
ip6hdr->src.addr[1] = lowpan6_contexts[i].addr[1];
#else
LWIP_UNUSED_ARG(lowpan6_contexts);
#endif
}
if ((lowpan6_buffer[1] & 0x30) == 0x10) {
MEMCPY(&ip6hdr->src.addr[2], lowpan6_buffer + lowpan6_offset, 8);
lowpan6_offset += 8;
} else if ((lowpan6_buffer[1] & 0x30) == 0x20) {
ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL);
ip6hdr->src.addr[3] = lwip_htonl(0xfe000000UL | (lowpan6_buffer[lowpan6_offset] << 8) | lowpan6_buffer[lowpan6_offset + 1]);
lowpan6_offset += 2;
} else if ((lowpan6_buffer[1] & 0x30) == 0x30) {
if (src->addr_len == 2) {
ip6hdr->src.addr[2] = PP_HTONL(0x000000ffUL);
ip6hdr->src.addr[3] = lwip_htonl(0xfe000000UL | (src->addr[0] << 8) | src->addr[1]);
} else {
ip6hdr->src.addr[2] = lwip_htonl(((src->addr[0] ^ 2) << 24) | (src->addr[1] << 16) | (src->addr[2] << 8) | src->addr[3]);
ip6hdr->src.addr[3] = lwip_htonl((src->addr[4] << 24) | (src->addr[5] << 16) | (src->addr[6] << 8) | src->addr[7]);
}
}
}
/* Destination address decoding. */
if (lowpan6_buffer[1] & 0x08) {
/* Multicast destination */
if (lowpan6_buffer[1] & 0x04) {
/* @todo support stateful multicast addressing */
return ERR_VAL;
}
if ((lowpan6_buffer[1] & 0x03) == 0x00) {
/* copy full address */
MEMCPY(&ip6hdr->dest.addr[0], lowpan6_buffer + lowpan6_offset, 16);
lowpan6_offset += 16;
} else if ((lowpan6_buffer[1] & 0x03) == 0x01) {
ip6hdr->dest.addr[0] = lwip_htonl(0xff000000UL | (lowpan6_buffer[lowpan6_offset++] << 16));
ip6hdr->dest.addr[1] = 0;
ip6hdr->dest.addr[2] = lwip_htonl(lowpan6_buffer[lowpan6_offset++]);
ip6hdr->dest.addr[3] = lwip_htonl((lowpan6_buffer[lowpan6_offset] << 24) | (lowpan6_buffer[lowpan6_offset + 1] << 16) | (lowpan6_buffer[lowpan6_offset + 2] << 8) | lowpan6_buffer[lowpan6_offset + 3]);
lowpan6_offset += 4;
} else if ((lowpan6_buffer[1] & 0x03) == 0x02) {
ip6hdr->dest.addr[0] = lwip_htonl(0xff000000UL | (lowpan6_buffer[lowpan6_offset++] << 16));
ip6hdr->dest.addr[1] = 0;
ip6hdr->dest.addr[2] = 0;
ip6hdr->dest.addr[3] = lwip_htonl((lowpan6_buffer[lowpan6_offset] << 16) | (lowpan6_buffer[lowpan6_offset + 1] << 8) | lowpan6_buffer[lowpan6_offset + 2]);
lowpan6_offset += 3;
} else if ((lowpan6_buffer[1] & 0x03) == 0x03) {
ip6hdr->dest.addr[0] = PP_HTONL(0xff020000UL);
ip6hdr->dest.addr[1] = 0;
ip6hdr->dest.addr[2] = 0;
ip6hdr->dest.addr[3] = lwip_htonl(lowpan6_buffer[lowpan6_offset++]);
}
} else {
if (lowpan6_buffer[1] & 0x04) {
/* Stateful destination compression */
/* Set prefix from context info */
if (lowpan6_buffer[1] & 0x80) {
i = lowpan6_buffer[2] & 0x0f;
} else {
i = 0;
}
if (i >= LWIP_6LOWPAN_NUM_CONTEXTS) {
/* Error */
return ERR_VAL;
}
#if LWIP_6LOWPAN_NUM_CONTEXTS > 0
ip6hdr->dest.addr[0] = lowpan6_contexts[i].addr[0];
ip6hdr->dest.addr[1] = lowpan6_contexts[i].addr[1];
#endif
} else {
/* Link local address compression */
ip6hdr->dest.addr[0] = PP_HTONL(0xfe800000UL);
ip6hdr->dest.addr[1] = 0;
}
if ((lowpan6_buffer[1] & 0x03) == 0x00) {
/* copy full address */
MEMCPY(&ip6hdr->dest.addr[0], lowpan6_buffer + lowpan6_offset, 16);
lowpan6_offset += 16;
} else if ((lowpan6_buffer[1] & 0x03) == 0x01) {
MEMCPY(&ip6hdr->dest.addr[2], lowpan6_buffer + lowpan6_offset, 8);
lowpan6_offset += 8;
} else if ((lowpan6_buffer[1] & 0x03) == 0x02) {
ip6hdr->dest.addr[2] = PP_HTONL(0x000000ffUL);
ip6hdr->dest.addr[3] = lwip_htonl(0xfe000000UL | (lowpan6_buffer[lowpan6_offset] << 8) | lowpan6_buffer[lowpan6_offset + 1]);
lowpan6_offset += 2;
} else if ((lowpan6_buffer[1] & 0x03) == 0x03) {
if (dest->addr_len == 2) {
ip6hdr->dest.addr[2] = PP_HTONL(0x000000ffUL);
ip6hdr->dest.addr[3] = lwip_htonl(0xfe000000UL | (dest->addr[0] << 8) | dest->addr[1]);
} else {
ip6hdr->dest.addr[2] = lwip_htonl(((dest->addr[0] ^ 2) << 24) | (dest->addr[1] << 16) | dest->addr[2] << 8 | dest->addr[3]);
ip6hdr->dest.addr[3] = lwip_htonl((dest->addr[4] << 24) | (dest->addr[5] << 16) | dest->addr[6] << 8 | dest->addr[7]);
}
}
}
/* Next Header Compression (NHC) decoding? */
if (lowpan6_buffer[0] & 0x04) {
#if LWIP_UDP
if ((lowpan6_buffer[lowpan6_offset] & 0xf8) == 0xf0) {
struct udp_hdr *udphdr;
/* UDP compression */
IP6H_NEXTH_SET(ip6hdr, IP6_NEXTH_UDP);
udphdr = (struct udp_hdr *)((u8_t *)decomp_buffer + ip6_offset);
if (decomp_bufsize < IP6_HLEN + UDP_HLEN) {
return ERR_MEM;
}
if (lowpan6_buffer[lowpan6_offset] & 0x04) {
/* @todo support checksum decompress */
return ERR_VAL;
}
/* Decompress ports */
i = lowpan6_buffer[lowpan6_offset++] & 0x03;
if (i == 0) {
udphdr->src = lwip_htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]);
udphdr->dest = lwip_htons(lowpan6_buffer[lowpan6_offset + 2] << 8 | lowpan6_buffer[lowpan6_offset + 3]);
lowpan6_offset += 4;
} else if (i == 0x01) {
udphdr->src = lwip_htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]);
udphdr->dest = lwip_htons(0xf000 | lowpan6_buffer[lowpan6_offset + 2]);
lowpan6_offset += 3;
} else if (i == 0x02) {
udphdr->src = lwip_htons(0xf000 | lowpan6_buffer[lowpan6_offset]);
udphdr->dest = lwip_htons(lowpan6_buffer[lowpan6_offset + 1] << 8 | lowpan6_buffer[lowpan6_offset + 2]);
lowpan6_offset += 3;
} else if (i == 0x03) {
udphdr->src = lwip_htons(0xf0b0 | ((lowpan6_buffer[lowpan6_offset] >> 4) & 0x0f));
udphdr->dest = lwip_htons(0xf0b0 | (lowpan6_buffer[lowpan6_offset] & 0x0f));
lowpan6_offset += 1;
}
udphdr->chksum = lwip_htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]);
lowpan6_offset += 2;
ip6_offset += UDP_HLEN;
if (datagram_size == 0) {
datagram_size = compressed_size - lowpan6_offset + ip6_offset;
}
udphdr->len = lwip_htons(datagram_size - IP6_HLEN);
} else
#endif /* LWIP_UDP */
{
/* @todo support NHC other than UDP */
return ERR_VAL;
}
}
if (datagram_size == 0) {
datagram_size = compressed_size - lowpan6_offset + ip6_offset;
}
/* Infer IPv6 payload length for header */
IP6H_PLEN_SET(ip6hdr, datagram_size - IP6_HLEN);
if (lowpan6_offset > lowpan6_bufsize) {
/* input buffer overflow */
return ERR_VAL;
}
*hdr_size_comp = lowpan6_offset;
*hdr_size_decomp = ip6_offset;
return ERR_OK;
}
struct pbuf *
lowpan6_decompress(struct pbuf *p, u16_t datagram_size, ip6_addr_t *lowpan6_contexts,
struct lowpan6_link_addr *src, struct lowpan6_link_addr *dest)
{
struct pbuf *q;
u16_t lowpan6_offset, ip6_offset;
err_t err;
#if LWIP_UDP
#define UDP_HLEN_ALLOC UDP_HLEN
#else
#define UDP_HLEN_ALLOC 0
#endif
/* Allocate a buffer for decompression. This buffer will be too big and will be
trimmed once the final size is known. */
q = pbuf_alloc(PBUF_IP, p->len + IP6_HLEN + UDP_HLEN_ALLOC, PBUF_POOL);
if (q == NULL) {
pbuf_free(p);
return NULL;
}
if (q->len < IP6_HLEN + UDP_HLEN_ALLOC) {
/* The headers need to fit into the first pbuf */
pbuf_free(p);
pbuf_free(q);
return NULL;
}
/* Decompress the IPv6 (and possibly UDP) header(s) into the new pbuf */
err = lowpan6_decompress_hdr((u8_t *)p->payload, p->len, (u8_t *)q->payload, q->len,
&lowpan6_offset, &ip6_offset, datagram_size, p->tot_len, lowpan6_contexts, src, dest);
if (err != ERR_OK) {
pbuf_free(p);
pbuf_free(q);
return NULL;
}
/* Now we copy leftover contents from p to q, so we have all L2 and L3 headers
(and L4?) in a single pbuf: */
/* Hide the compressed headers in p */
pbuf_remove_header(p, lowpan6_offset);
/* Temporarily hide the headers in q... */
pbuf_remove_header(q, ip6_offset);
/* ... copy the rest of p into q... */
pbuf_copy(q, p);
/* ... and reveal the headers again... */
pbuf_add_header_force(q, ip6_offset);
/* ... trim the pbuf to its correct size... */
pbuf_realloc(q, ip6_offset + p->len);
/* ... and cat possibly remaining (data-only) pbufs */
if (p->next != NULL) {
pbuf_cat(q, p->next);
}
/* the original (first) pbuf can now be freed */
p->next = NULL;
pbuf_free(p);
/* all done */
return q;
}
#endif /* LWIP_6LOWPAN_IPHC */
#endif /* LWIP_IPV6 */
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