nes-proj/os/services/lwm2m/lwm2m-tlv.c

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/*
* Copyright (c) 2015-2018, Yanzi Networks AB.
* 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 copyright holder 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 COPYRIGHT HOLDER 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
* COPYRIGHT HOLDER 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.
*/
/**
* \addtogroup lwm2m
* @{
*
*/
/**
* \file
* Implementation of the Contiki OMA LWM2M TLV
* \author
* Joakim Eriksson <joakime@sics.se>
* Niclas Finne <nfi@sics.se>
*/
#include <string.h>
#include <stdint.h>
#include "lwm2m-tlv.h"
/* Log configuration */
#include "coap-log.h"
#define LOG_MODULE "lwm2m-tlv"
#define LOG_LEVEL LOG_LEVEL_NONE
/*---------------------------------------------------------------------------*/
static inline uint8_t
get_len_type(const lwm2m_tlv_t *tlv)
{
if(tlv->length < 8) {
return 0;
} else if(tlv->length < 256) {
return 1;
} else if(tlv->length < 0x10000) {
return 2;
} else {
return 3;
}
}
/*---------------------------------------------------------------------------*/
size_t
lwm2m_tlv_read(lwm2m_tlv_t *tlv, const uint8_t *buffer, size_t len)
{
uint8_t len_type;
uint8_t len_pos = 1;
size_t tlv_len;
tlv->type = (buffer[0] >> 6) & 3;
len_type = (buffer[0] >> 3) & 3;
len_pos = 1 + (((buffer[0] & (1 << 5)) != 0) ? 2 : 1);
tlv->id = buffer[1];
/* if len_pos is larger than two it means that there is more ID to read */
if(len_pos > 2) {
tlv->id = (tlv->id << 8) + buffer[2];
}
if(len_type == 0) {
tlv_len = buffer[0] & 7;
} else {
/* read the length */
tlv_len = 0;
while(len_type > 0) {
tlv_len = tlv_len << 8 | buffer[len_pos++];
len_type--;
}
}
/* and read out the data??? */
tlv->length = tlv_len;
tlv->value = &buffer[len_pos];
return len_pos + tlv_len;
}
/*---------------------------------------------------------------------------*/
size_t
lwm2m_tlv_get_size(const lwm2m_tlv_t *tlv)
{
size_t size;
/* first hdr + len size */
size = 1 + get_len_type(tlv);
/* id size */
size += (tlv->id > 255) ? 2 : 1;
/* and the length */
size += tlv->length;
return size;
}
/*---------------------------------------------------------------------------*/
/* If the tlv->value is NULL - only the header will be generated - useful for
* large strings or opaque streaming (block transfer)
*/
size_t
lwm2m_tlv_write(const lwm2m_tlv_t *tlv, uint8_t *buffer, size_t buffersize)
{
int pos;
uint8_t len_type;
/* len type is the same as number of bytes required for length */
len_type = get_len_type(tlv);
pos = 1 + len_type;
/* ensure that we do not write too much */
if(tlv->value != NULL && buffersize < tlv->length + pos) {
LOG_WARN("Could not write the TLV - buffer overflow.\n");
return 0;
}
if(buffersize < pos + 2) {
return 0;
}
/* first type byte in TLV header */
buffer[0] = (tlv->type << 6) |
(tlv->id > 255 ? (1 << 5) : 0) |
(len_type << 3) |
(len_type == 0 ? tlv->length : 0);
pos = 1;
/* The ID */
if(tlv->id > 255) {
buffer[pos++] = (tlv->id >> 8) & 0xff;
}
buffer[pos++] = tlv->id & 0xff;
/* Add length if needed - unrolled loop ? */
if(len_type > 2) {
buffer[pos++] = (tlv->length >> 16) & 0xff;
}
if(len_type > 1) {
buffer[pos++] = (tlv->length >> 8) & 0xff;
}
if(len_type > 0) {
buffer[pos++] = tlv->length & 0xff;
}
/* finally add the value */
if(tlv->value != NULL && tlv->length > 0) {
memcpy(&buffer[pos], tlv->value, tlv->length);
}
if(LOG_DBG_ENABLED) {
int i;
LOG_DBG("TLV: ");
for(i = 0; i < pos + ((tlv->value != NULL) ? tlv->length : 0); i++) {
LOG_DBG_("%02x", buffer[i]);
}
LOG_DBG_("\n");
}
return pos + ((tlv->value != NULL) ? tlv->length : 0);
}
/*---------------------------------------------------------------------------*/
int32_t
lwm2m_tlv_get_int32(const lwm2m_tlv_t *tlv)
{
int i;
int32_t value = 0;
for(i = 0; i < tlv->length; i++) {
value = (value << 8) | tlv->value[i];
}
/* Ensure that we set all the bits above what we read in */
if(tlv->value[0] & 0x80) {
while(i < 4) {
value = value | (0xff << (i * 8));
i++;
}
}
return value;
}
/*---------------------------------------------------------------------------*/
size_t
lwm2m_tlv_write_int32(uint8_t type, int16_t id, int32_t value, uint8_t *buffer, size_t len)
{
lwm2m_tlv_t tlv;
uint8_t buf[4];
int i;
int v;
int last_bit;
LOG_DBG("Exporting int32 %d %"PRId32" ", id, value);
v = value < 0 ? -1 : 0;
i = 0;
do {
buf[3 - i] = value & 0xff;
/* check if the last MSB indicates that we need another byte */
last_bit = (v == 0 && (value & 0x80) > 0) || (v == -1 && (value & 0x80) == 0);
value = value >> 8;
i++;
} while((value != v || last_bit) && i < 4);
/* export INT as TLV */
LOG_DBG("len: %d\n", i);
tlv.type = type;
tlv.length = i;
tlv.value = &buf[3 - (i - 1)];
tlv.id = id;
return lwm2m_tlv_write(&tlv, buffer, len);
}
/*---------------------------------------------------------------------------*/
/* convert fixpoint 32-bit to a IEEE Float in the byte array*/
size_t
lwm2m_tlv_write_float32(uint8_t type, int16_t id, int32_t value, int bits,
uint8_t *buffer, size_t len)
{
int i;
int e = 0;
int32_t val = 0;
int32_t v;
uint8_t b[4];
lwm2m_tlv_t tlv;
v = value;
if(v < 0) {
v = -v;
}
while(v > 1) {
val = (val >> 1);
if (v & 1) {
val = val | (1L << 22);
}
v = (v >> 1);
e++;
}
LOG_DBG("Sign: %d, Fraction: %06"PRIx32" 0b", value < 0, val);
for(i = 0; i < 23; i++) {
LOG_DBG_("%"PRId32"", ((val >> (22 - i)) & 1));
}
LOG_DBG_("\nExp:%d\n", e);
/* convert to the thing we should have */
e = e - bits + 127;
if(value == 0) {
e = 0;
}
/* is this the right byte order? */
b[0] = (value < 0 ? 0x80 : 0) | (e >> 1);
b[1] = ((e & 1) << 7) | ((val >> 16) & 0x7f);
b[2] = (val >> 8) & 0xff;
b[3] = val & 0xff;
LOG_DBG("B=%02x%02x%02x%02x\n", b[0], b[1], b[2], b[3]);
/* construct the TLV */
tlv.type = type;
tlv.length = 4;
tlv.value = b;
tlv.id = id;
return lwm2m_tlv_write(&tlv, buffer, len);
}
/*---------------------------------------------------------------------------*/
/* convert float to fixpoint */
size_t
lwm2m_tlv_float32_to_fix(const lwm2m_tlv_t *tlv, int32_t *value, int bits)
{
/* TLV needs to be 4 bytes */
int e, i;
int32_t val;
int sign = (tlv->value[0] & 0x80) != 0;
e = ((tlv->value[0] << 1) & 0xff) | (tlv->value[1] >> 7);
val = (((long)tlv->value[1] & 0x7f) << 16) | (tlv->value[2] << 8) | tlv->value[3];
LOG_DBG("Sign: %d, Fraction: %06"PRIx32" 0b", val < 0, val);
for(i = 0; i < 23; i++) {
LOG_DBG_("%"PRId32"", ((val >> (22 - i)) & 1));
}
LOG_DBG("\nExp:%d => %d\n", e, e - 127);
e = e - 127 + bits;
/* e corresponds to the number of times we need to roll the number */
LOG_DBG("Actual e=%d\n", e);
e = e - 23;
LOG_DBG("E after sub %d\n", e);
val = val | 1L << 23;
if(e > 0) {
val = val << e;
} else {
val = val >> -e;
}
*value = sign ? -val : val;
return 4;
}
/*---------------------------------------------------------------------------*/
/** @} */
#if 0
int main(int argc, char *argv[])
{
lwm2m_tlv_t tlv;
uint8_t data[24];
/* Make -1 */
tlv.length = 2;
tlv.value = data;
data[0] = 0x00;
data[1] = 0x80,
printf("TLV:%d\n", lwm2m_tlv_get_int32(&tlv));
printf("Len: %d\n", lwm2m_tlv_write_int32(0, 1, -0x88987f, data, 24));
}
#endif