osd-contiki/core/net/rime/chameleon-bitopt.c

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/*
* Copyright (c) 2007, 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.
*
* This file is part of the Contiki operating system.
*/
/**
* \file
* A Chameleon module that produces bit-optimized headers
* \author
* Adam Dunkels <adam@sics.se>
*/
#include "net/rime/chameleon.h"
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#include "net/rime/rime.h"
#include <string.h>
/* This option enables an optimization where the link addresses are
left to the MAC RDC and not encoded in the Chameleon header.
Note: this requires that the underlying MAC layer to add link
addresses and will not work together with for example nullrdc.
*/
#ifdef CHAMELEON_CONF_WITH_MAC_LINK_ADDRESSES
#define CHAMELEON_WITH_MAC_LINK_ADDRESSES CHAMELEON_CONF_WITH_MAC_LINK_ADDRESSES
#else /* !CHAMELEON_CONF_WITH_MAC_LINK_ADDRESSES */
#define CHAMELEON_WITH_MAC_LINK_ADDRESSES 0
#endif /* !CHAMELEON_CONF_WITH_MAC_LINK_ADDRESSES */
struct bitopt_hdr {
uint8_t channel[2];
};
#define BITOPT_HDR_SIZE 2
static const uint8_t bitmask[9] = { 0x00, 0x80, 0xc0, 0xe0, 0xf0,
0xf8, 0xfc, 0xfe, 0xff };
#define DEBUG 0
#if DEBUG
#include <stdio.h>
#define PRINTF(...) printf(__VA_ARGS__)
#else
#define PRINTF(...)
#endif
/*---------------------------------------------------------------------------*/
/* For get_bits/set_bits functions in this file to work correctly,
* the values contained in packetbuf_attr_t variables (uint16_t internally)
* must be in little endian byte order.
*/
/* Write little endian 16 bit value */
static void CC_INLINE
le16_write(void *ptr, uint16_t v)
{
uint8_t *p = (uint8_t *)ptr;
p[0] = v & 0xff;
p[1] = v >> 8;
}
/*---------------------------------------------------------------------------*/
/* Read little endian 16 bit value */
static uint16_t CC_INLINE
le16_read(const void *ptr)
{
const uint8_t *p = (const uint8_t *)ptr;
return ((uint16_t)p[1] << 8) | p[0];
}
/*---------------------------------------------------------------------------*/
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static uint8_t CC_INLINE
get_bits_in_byte(uint8_t *from, int bitpos, int vallen)
{
uint16_t shifted_val;
shifted_val = (from[0] << 8) | from[1];
/* PRINTF("get_bits_in_byte: from[0] 0x%02x from[1] 0x%02x shifted_val 0x%04x, return 0x%02x vallen %d\n",
from[0], from[1], shifted_val,
(((shifted_val << bitpos) >> 8) & bitmask[vallen]) >> (8 - vallen),
vallen
);*/
return (((shifted_val << bitpos) >> 8) & bitmask[vallen]) >> (8 - vallen);
}
/*---------------------------------------------------------------------------*/
void
get_bits(uint8_t *to, uint8_t *from, int bitpos, int vallen)
{
int i, bits;
if(vallen < 8) {
*to = get_bits_in_byte(from, bitpos, vallen);
} else {
if(bitpos == 0) {
for(i = 0; i < vallen / 8; ++i) {
/* PRINTF("get_bits i %d val 0x%02x\n",
i, from[i]);*/
to[i] = from[i];
}
bits = vallen & 7;
if(bits) {
to[i] = get_bits_in_byte(&from[i], 0, bits);
}
} else {
for(i = 0; i < vallen / 8; ++i) {
/* PRINTF("get_bits i %d val 0x%02x bitpos %d\n",
i, from[i], bitpos);*/
to[i] = get_bits_in_byte(&from[i], bitpos, 8);
}
bits = vallen & 7;
if(bits) {
to[i] = get_bits_in_byte(&from[i], bitpos, bits);
}
}
}
}
/*---------------------------------------------------------------------------*/
static int
header_size(const struct packetbuf_attrlist *a)
{
int size, len;
/* Compute the total size of the final header by summing the size of
all attributes that are used on this channel. */
size = 0;
for(; a->type != PACKETBUF_ATTR_NONE; ++a) {
#if CHAMELEON_WITH_MAC_LINK_ADDRESSES
if(a->type == PACKETBUF_ADDR_SENDER ||
a->type == PACKETBUF_ADDR_RECEIVER) {
/* Let the link layer handle sender and receiver */
continue;
}
#endif /* CHAMELEON_WITH_MAC_LINK_ADDRESSES */
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/* PRINTF("chameleon header_size: header type %d len %d\n",
a->type, a->len);*/
len = a->len;
/* if(len < 8) {
len = 8;
}*/
size += len;
}
return size;
}
/*---------------------------------------------------------------------------*/
static void CC_INLINE
set_bits_in_byte(uint8_t *target, int bitpos, uint8_t val, int vallen)
{
unsigned short shifted_val;
shifted_val = val << (8 - bitpos + 8 - vallen);
/* printf("set_bits_in_byte before target[0] 0x%02x target[1] 0x%02x shifted_val 0x%04x val 0x%02x vallen %d\n",
target[0], target[1], shifted_val, val, vallen);*/
target[0] |= shifted_val >> 8;
target[1] |= shifted_val & 0xff;
}
/*---------------------------------------------------------------------------*/
void
set_bits(uint8_t *ptr, int bitpos, uint8_t *val, int vallen)
{
int i, bits;
/* PRINTF("set_bits %p bitpos %d, val %p len %d\n",
ptr, bitpos, val, vallen);*/
if(vallen < 8) {
set_bits_in_byte(ptr, bitpos, *val /*>> (8 - vallen)*/, vallen);
} else {
if(bitpos == 0) {
for(i = 0; i < vallen / 8; ++i) {
/* PRINTF("set_bits i %d val %d\n",
i, val[i]);*/
ptr[i] = val[i];
}
bits = vallen & 7;
if(bits) {
set_bits_in_byte(&ptr[i], 0, val[i] >> (8 - bits), bits);
}
} else {
for(i = 0; i < vallen / 8; ++i) {
/* PRINTF("set_bits i %d val %d\n",
i, val[i]);*/
set_bits_in_byte(&ptr[i], bitpos, val[i], 8);
}
bits = vallen & 7;
if(bits) {
set_bits_in_byte(&ptr[i], 0, val[i] >> (8 - bits + bitpos), bits);
}
}
}
}
/*---------------------------------------------------------------------------*/
#if 0
static void
printbin(int n, int digits)
{
int i;
char output[128];
for(i = 0; i < digits; ++i) {
output[digits - i - 1] = (n & 1) + '0';
n >>= 1;
}
output[i] = 0;
printf(output);
}
static void
printhdr(uint8_t *hdr, int len)
{
int i, j;
j = 0;
for(i = 0; i < len; ++i) {
printbin(hdr[i], 8);
printf(", ");
++j;
if(j == 10) {
printf("\n");
j = 0;
}
}
if(j != 0) {
printf("\n");
}
}
#endif
/*---------------------------------------------------------------------------*/
static int
pack_header(struct channel *c)
{
const struct packetbuf_attrlist *a;
int hdrbytesize;
int byteptr, bitptr, len;
uint8_t *hdrptr;
struct bitopt_hdr *hdr;
/* Compute the total size of the final header by summing the size of
all attributes that are used on this channel. */
hdrbytesize = c->hdrsize / 8 + ((c->hdrsize & 7) == 0? 0: 1);
if(packetbuf_hdralloc(hdrbytesize + BITOPT_HDR_SIZE) == 0) {
PRINTF("chameleon-bitopt: insufficient space for headers\n");
return 0;
}
hdr = (struct bitopt_hdr *)packetbuf_hdrptr();
hdr->channel[0] = c->channelno & 0xff;
hdr->channel[1] = (c->channelno >> 8) & 0xff;
hdrptr = ((uint8_t *)packetbuf_hdrptr()) + BITOPT_HDR_SIZE;
memset(hdrptr, 0, hdrbytesize);
byteptr = bitptr = 0;
for(a = c->attrlist; a->type != PACKETBUF_ATTR_NONE; ++a) {
#if CHAMELEON_WITH_MAC_LINK_ADDRESSES
if(a->type == PACKETBUF_ADDR_SENDER ||
a->type == PACKETBUF_ADDR_RECEIVER) {
/* Let the link layer handle sender and receiver */
PRINTF("%d.%d: pack_header leaving sender/receiver to link layer\n");
continue;
}
#endif /* CHAMELEON_WITH_MAC_LINK_ADDRESSES */
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PRINTF("%d.%d: pack_header type %d, len %d, bitptr %d, ",
linkaddr_node_addr.u8[0], linkaddr_node_addr.u8[1],
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a->type, a->len, bitptr);
/* len = (a->len & 0xf8) + ((a->len & 7) ? 8: 0);*/
len = a->len;
byteptr = bitptr / 8;
if(PACKETBUF_IS_ADDR(a->type)) {
set_bits(&hdrptr[byteptr], bitptr & 7,
(uint8_t *)packetbuf_addr(a->type), len);
PRINTF("address %d.%d\n",
/* linkaddr_node_addr.u8[0], linkaddr_node_addr.u8[1],*/
((uint8_t *)packetbuf_addr(a->type))[0],
((uint8_t *)packetbuf_addr(a->type))[1]);
} else {
uint8_t buffer[2];
packetbuf_attr_t val = packetbuf_attr(a->type);
le16_write(buffer, val);
set_bits(&hdrptr[byteptr], bitptr & 7, buffer, len);
PRINTF("value %d\n",
/*linkaddr_node_addr.u8[0], linkaddr_node_addr.u8[1],*/
val);
}
/* printhdr(hdrptr, hdrbytesize);*/
bitptr += len;
}
/* printhdr(hdrptr, hdrbytesize);*/
return 1; /* Send out packet */
}
/*---------------------------------------------------------------------------*/
static struct channel *
unpack_header(void)
{
const struct packetbuf_attrlist *a;
int byteptr, bitptr, len;
int hdrbytesize;
uint8_t *hdrptr;
struct bitopt_hdr *hdr;
struct channel *c;
/* The packet has a header that tells us what channel the packet is
for. */
hdr = (struct bitopt_hdr *)packetbuf_dataptr();
if(packetbuf_hdrreduce(BITOPT_HDR_SIZE) == 0) {
PRINTF("chameleon-bitopt: too short packet\n");
return NULL;
}
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c = channel_lookup((hdr->channel[1] << 8) + hdr->channel[0]);
if(c == NULL) {
PRINTF("chameleon-bitopt: input: channel %u not found\n",
(hdr->channel[1] << 8) + hdr->channel[0]);
return NULL;
}
hdrptr = packetbuf_dataptr();
hdrbytesize = c->hdrsize / 8 + ((c->hdrsize & 7) == 0? 0: 1);
if(packetbuf_hdrreduce(hdrbytesize) == 0) {
PRINTF("chameleon-bitopt: too short packet\n");
return NULL;
}
byteptr = bitptr = 0;
for(a = c->attrlist; a->type != PACKETBUF_ATTR_NONE; ++a) {
#if CHAMELEON_WITH_MAC_LINK_ADDRESSES
if(a->type == PACKETBUF_ADDR_SENDER ||
a->type == PACKETBUF_ADDR_RECEIVER) {
/* Let the link layer handle sender and receiver */
continue;
}
#endif /* CHAMELEON_WITH_MAC_LINK_ADDRESSES */
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PRINTF("%d.%d: unpack_header type %d, len %d, bitptr %d\n",
linkaddr_node_addr.u8[0], linkaddr_node_addr.u8[1],
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a->type, a->len, bitptr);
/* len = (a->len & 0xf8) + ((a->len & 7) ? 8: 0);*/
len = a->len;
byteptr = bitptr / 8;
if(PACKETBUF_IS_ADDR(a->type)) {
linkaddr_t addr;
get_bits((uint8_t *)&addr, &hdrptr[byteptr], bitptr & 7, len);
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PRINTF("%d.%d: unpack_header type %d, addr %d.%d\n",
linkaddr_node_addr.u8[0], linkaddr_node_addr.u8[1],
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a->type, addr.u8[0], addr.u8[1]);
packetbuf_set_addr(a->type, &addr);
} else {
packetbuf_attr_t val;
uint8_t buffer[2] = {0};
get_bits(buffer, &hdrptr[byteptr], bitptr & 7, len);
val = le16_read(buffer);
packetbuf_set_attr(a->type, val);
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PRINTF("%d.%d: unpack_header type %d, val %d\n",
linkaddr_node_addr.u8[0], linkaddr_node_addr.u8[1],
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a->type, val);
}
/* byteptr += len / 8;*/
bitptr += len;
}
return c;
}
/*---------------------------------------------------------------------------*/
CC_CONST_FUNCTION struct chameleon_module chameleon_bitopt = {
unpack_header,
pack_header,
header_size
};
/*---------------------------------------------------------------------------*/