378 lines
10 KiB
C++
378 lines
10 KiB
C++
/* -*- c++ -*- */
|
|
/*
|
|
* gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
|
|
*
|
|
* Copyright (C) 2019, Libre Space Foundation <http://libre.space>
|
|
*
|
|
* This program is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* 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.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
#include "config.h"
|
|
#endif
|
|
|
|
#include <gnuradio/io_signature.h>
|
|
#include <satnogs/log.h>
|
|
#include <satnogs/ieee802_15_4_variant_decoder.h>
|
|
#include <satnogs/metadata.h>
|
|
|
|
#include <arpa/inet.h>
|
|
|
|
|
|
namespace gr {
|
|
namespace satnogs {
|
|
|
|
decoder::decoder_sptr
|
|
ieee802_15_4_variant_decoder::make(const std::vector<uint8_t> &preamble,
|
|
size_t preamble_threshold,
|
|
const std::vector<uint8_t> &sync,
|
|
size_t sync_threshold,
|
|
crc::crc_t crc,
|
|
whitening::whitening_sptr descrambler,
|
|
bool var_len,
|
|
size_t max_len)
|
|
{
|
|
return decoder::decoder_sptr(
|
|
new ieee802_15_4_variant_decoder(preamble, preamble_threshold,
|
|
sync, sync_threshold, crc,
|
|
descrambler, var_len, max_len));
|
|
}
|
|
|
|
ieee802_15_4_variant_decoder::ieee802_15_4_variant_decoder(
|
|
const std::vector<uint8_t> &preamble,
|
|
size_t preamble_threshold,
|
|
const std::vector<uint8_t> &sync,
|
|
size_t sync_threshold,
|
|
crc::crc_t crc,
|
|
whitening::whitening_sptr descrambler,
|
|
bool var_len, size_t max_len) :
|
|
decoder(sizeof(uint8_t), max_len),
|
|
d_preamble(preamble.size() * 8),
|
|
d_preamble_shift_reg(preamble.size() * 8),
|
|
d_preamble_len(preamble.size() * 8),
|
|
d_preamble_thrsh(preamble_threshold),
|
|
d_sync(sync.size() * 8),
|
|
d_sync_shift_reg(sync.size() * 8),
|
|
d_sync_len(sync.size() * 8),
|
|
d_sync_thrsh(sync_threshold),
|
|
d_descrambler(descrambler),
|
|
d_crc(crc),
|
|
d_var_len(var_len),
|
|
d_len(max_len + crc::crc_size(crc)),
|
|
d_length_field_len(0),
|
|
d_state(SEARCHING),
|
|
d_cnt(0),
|
|
d_pdu(new uint8_t[max_len])
|
|
{
|
|
for (uint8_t b : preamble) {
|
|
d_preamble <<= (b >> 7);
|
|
d_preamble <<= ((b >> 6) & 0x1);
|
|
d_preamble <<= ((b >> 5) & 0x1);
|
|
d_preamble <<= ((b >> 4) & 0x1);
|
|
d_preamble <<= ((b >> 3) & 0x1);
|
|
d_preamble <<= ((b >> 2) & 0x1);
|
|
d_preamble <<= ((b >> 1) & 0x1);
|
|
d_preamble <<= (b & 0x1);
|
|
}
|
|
for (uint8_t b : sync) {
|
|
d_sync <<= (b >> 7);
|
|
d_sync <<= ((b >> 6) & 0x1);
|
|
d_sync <<= ((b >> 5) & 0x1);
|
|
d_sync <<= ((b >> 4) & 0x1);
|
|
d_sync <<= ((b >> 3) & 0x1);
|
|
d_sync <<= ((b >> 2) & 0x1);
|
|
d_sync <<= ((b >> 1) & 0x1);
|
|
d_sync <<= (b & 0x1);
|
|
}
|
|
|
|
/* Parameters checking */
|
|
if (max_len == 0) {
|
|
throw std::invalid_argument(
|
|
"The maximum frame size should be at least 1 byte");
|
|
}
|
|
|
|
if (d_sync_len < 8) {
|
|
throw std::invalid_argument("SYNC word should be at least 8 bits");
|
|
}
|
|
|
|
if (d_preamble_len < 8) {
|
|
throw std::invalid_argument("Preamble should be at least 8 bits");
|
|
}
|
|
|
|
if (d_preamble_len < 2 * d_preamble_thrsh) {
|
|
throw std::invalid_argument(
|
|
"Too many error bits are allowed for the preamble."
|
|
"Consider lowering the threshold");
|
|
}
|
|
|
|
if (d_sync_len < 2 * d_sync_thrsh) {
|
|
throw std::invalid_argument(
|
|
"Too many error bits are allowed for the sync word. "
|
|
"Consider lowering the threshold");
|
|
}
|
|
|
|
if (var_len) {
|
|
d_length_field_len = 1;
|
|
}
|
|
}
|
|
|
|
ieee802_15_4_variant_decoder::~ieee802_15_4_variant_decoder()
|
|
{
|
|
delete [] d_pdu;
|
|
}
|
|
|
|
decoder_status_t
|
|
ieee802_15_4_variant_decoder::decode(const void *in, int len)
|
|
{
|
|
if (d_var_len) {
|
|
return decode_var_len(in, len);
|
|
}
|
|
return decode_const_len(in, len);
|
|
}
|
|
|
|
void
|
|
ieee802_15_4_variant_decoder::reset()
|
|
{
|
|
if (d_descrambler) {
|
|
d_descrambler->reset();
|
|
}
|
|
d_cnt = 0;
|
|
d_state = SEARCHING;
|
|
d_preamble_shift_reg.reset();
|
|
d_sync_shift_reg.reset();
|
|
}
|
|
|
|
decoder_status_t
|
|
ieee802_15_4_variant_decoder::decode_var_len(const void *in, int len)
|
|
{
|
|
decoder_status_t status;
|
|
switch (d_state) {
|
|
case SEARCHING:
|
|
status.consumed = search_preamble((const uint8_t *) in, len);
|
|
break;
|
|
case SEARCHING_SYNC:
|
|
status.consumed = search_sync((const uint8_t *) in, len);
|
|
break;
|
|
case DECODING_GENERIC_FRAME_LEN:
|
|
status.consumed = decode_frame_len((const uint8_t *) in);
|
|
break;
|
|
case DECODING_PAYLOAD:
|
|
decode_payload(status, (const uint8_t *) in, len);
|
|
break;
|
|
default:
|
|
throw std::runtime_error("ieee802_15_4_variant_decoder: Invalid state");
|
|
}
|
|
return status;
|
|
}
|
|
|
|
decoder_status_t
|
|
ieee802_15_4_variant_decoder::decode_const_len(const void *in, int len)
|
|
{
|
|
decoder_status_t status;
|
|
switch (d_state) {
|
|
case SEARCHING:
|
|
status.consumed = search_preamble((const uint8_t *) in, len);
|
|
break;
|
|
case SEARCHING_SYNC:
|
|
status.consumed = search_preamble((const uint8_t *) in, len);
|
|
break;
|
|
case DECODING_PAYLOAD:
|
|
decode_payload(status, (const uint8_t *) in, len);
|
|
break;
|
|
default:
|
|
throw std::runtime_error("ieee802_15_4_variant_decoder: Invalid state");
|
|
}
|
|
return status;
|
|
}
|
|
|
|
/**
|
|
* To greatly simplify the logic, the decoder requests that the number of
|
|
* input items should be a multiple of 8
|
|
* @return 8
|
|
*/
|
|
size_t
|
|
ieee802_15_4_variant_decoder::input_multiple() const
|
|
{
|
|
return 8;
|
|
}
|
|
|
|
int
|
|
ieee802_15_4_variant_decoder::search_preamble(const uint8_t *in, int len)
|
|
{
|
|
for (int i = 0; i < len; i++) {
|
|
d_preamble_shift_reg <<= in[i];
|
|
shift_reg tmp = d_preamble_shift_reg ^ d_preamble;
|
|
if (tmp.count() <= d_preamble_thrsh) {
|
|
d_state = SEARCHING_SYNC;
|
|
d_cnt = 0;
|
|
return i + 1;
|
|
}
|
|
}
|
|
return len;
|
|
}
|
|
|
|
int
|
|
ieee802_15_4_variant_decoder::search_sync(const uint8_t *in, int len)
|
|
{
|
|
for (int i = 0; i < len; i++) {
|
|
d_sync_shift_reg <<= in[i];
|
|
shift_reg tmp = d_sync_shift_reg ^ d_sync;
|
|
d_cnt++;
|
|
if (tmp.count() <= d_sync_thrsh) {
|
|
if (d_var_len) {
|
|
d_state = DECODING_GENERIC_FRAME_LEN;
|
|
}
|
|
else {
|
|
d_state = DECODING_PAYLOAD;
|
|
}
|
|
d_cnt = 0;
|
|
return i + 1;
|
|
}
|
|
|
|
/* The sync word should be available by now */
|
|
if (d_cnt > d_preamble_len * 2 + d_sync_len) {
|
|
reset();
|
|
return i + 1;
|
|
}
|
|
}
|
|
return len;
|
|
}
|
|
|
|
int
|
|
ieee802_15_4_variant_decoder::decode_frame_len(const uint8_t *in)
|
|
{
|
|
uint8_t b = 0x0;
|
|
b |= in[0] << 7;
|
|
b |= in[1] << 6;
|
|
b |= in[2] << 5;
|
|
b |= in[3] << 4;
|
|
b |= in[4] << 3;
|
|
b |= in[5] << 2;
|
|
b |= in[6] << 1;
|
|
b |= in[7];
|
|
|
|
if (d_descrambler) {
|
|
uint8_t descrambled = 0x0;
|
|
d_descrambler->descramble((uint8_t *)&descrambled,
|
|
(const uint8_t *)&b, 1, false);
|
|
d_len = descrambled;
|
|
d_pdu[0] = descrambled;
|
|
}
|
|
else {
|
|
d_len = b;
|
|
d_pdu[0] = b;
|
|
}
|
|
d_len += crc::crc_size(d_crc);
|
|
/* Length field is needed for the CRC calculation */
|
|
d_cnt = 1;
|
|
d_state = DECODING_PAYLOAD;
|
|
return 8;
|
|
}
|
|
|
|
void
|
|
ieee802_15_4_variant_decoder::decode_payload(decoder_status_t &status,
|
|
const uint8_t *in, int len)
|
|
{
|
|
const int s = len / 8;
|
|
for (int i = 0; i < s; i++) {
|
|
uint8_t b = 0x0;
|
|
b = in[i * 8] << 7;
|
|
b |= in[i * 8 + 1] << 6;
|
|
b |= in[i * 8 + 2] << 5;
|
|
b |= in[i * 8 + 3] << 4;
|
|
b |= in[i * 8 + 4] << 3;
|
|
b |= in[i * 8 + 5] << 2;
|
|
b |= in[i * 8 + 6] << 1;
|
|
b |= in[i * 8 + 7];
|
|
d_pdu[d_cnt++] = b;
|
|
if (d_cnt == d_len + d_length_field_len) {
|
|
if (d_descrambler) {
|
|
d_descrambler->descramble(d_pdu + d_length_field_len,
|
|
d_pdu + d_length_field_len, d_len, false);
|
|
}
|
|
|
|
status.decode_success = true;
|
|
status.consumed = (i + 1) * 8;
|
|
if (check_crc()) {
|
|
metadata::add_time_iso8601(status.data);
|
|
metadata::add_pdu(status.data, d_pdu + d_length_field_len,
|
|
d_len - crc::crc_size(d_crc));
|
|
metadata::add_crc_valid(status.data, true);
|
|
}
|
|
else {
|
|
metadata::add_pdu(status.data, d_pdu + d_length_field_len, d_len);
|
|
metadata::add_crc_valid(status.data, false);
|
|
}
|
|
reset();
|
|
return;
|
|
}
|
|
}
|
|
status.consumed = s * 8;
|
|
}
|
|
|
|
bool
|
|
ieee802_15_4_variant_decoder::check_crc()
|
|
{
|
|
uint16_t crc16_c;
|
|
uint16_t crc16_received;
|
|
uint32_t crc32_c;
|
|
uint32_t crc32_received;
|
|
switch (d_crc) {
|
|
case crc::CRC_NONE:
|
|
return true;
|
|
case crc::CRC16_CCITT:
|
|
crc16_c = crc::crc16_ccitt(d_pdu, d_len + d_length_field_len - 2);
|
|
memcpy(&crc16_received, d_pdu + d_length_field_len + d_len - 2, 2);
|
|
crc16_received = ntohs(crc16_received);
|
|
LOG_DEBUG("Received: 0x%02x Computed: 0x%02x", crc16_received, crc16_c);
|
|
if (crc16_c == crc16_received) {
|
|
return true;
|
|
}
|
|
return false;
|
|
case crc::CRC16_CCITT_REVERSED:
|
|
crc16_c = crc::crc16_ccitt_reversed(d_pdu, d_len + d_length_field_len - 2);
|
|
memcpy(&crc16_received, d_pdu + d_length_field_len + d_len - 2, 2);
|
|
crc16_received = ntohs(crc16_received);
|
|
LOG_DEBUG("Received: 0x%02x Computed: 0x%02x", crc16_received, crc16_c);
|
|
if (crc16_c == crc16_received) {
|
|
return true;
|
|
}
|
|
return false;
|
|
case crc::CRC16_IBM:
|
|
crc16_c = crc::crc16_ibm(d_pdu, d_len + d_length_field_len - 2);
|
|
memcpy(&crc16_received, d_pdu + d_length_field_len + d_len - 2, 2);
|
|
crc16_received = ntohs(crc16_received);
|
|
LOG_DEBUG("Received: 0x%02x Computed: 0x%02x", crc16_received, crc16_c);
|
|
if (crc16_c == crc16_received) {
|
|
return true;
|
|
}
|
|
return false;
|
|
case crc::CRC32_C:
|
|
crc32_c = crc::crc32_c(d_pdu, d_len + d_length_field_len - 4);
|
|
memcpy(&crc32_received, d_pdu + d_length_field_len + d_len - 4, 4);
|
|
crc32_received = ntohl(crc32_received);
|
|
LOG_DEBUG("Received: 0x%02x Computed: 0x%02x", crc32_received, crc32_c);
|
|
if (crc32_c == crc32_received) {
|
|
return true;
|
|
}
|
|
return false;
|
|
default:
|
|
throw std::runtime_error("ieee802_15_4_variant_decoder: Invalid CRC");
|
|
}
|
|
}
|
|
|
|
} /* namespace satnogs */
|
|
} /* namespace gr */
|
|
|