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dvmhost/p25/data/DataBlock.cpp

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/**
* Digital Voice Modem - Host Software
* GPLv2 Open Source. Use is subject to license terms.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* @package DVM / Host Software
*
*/
/*
* Copyright (C) 2018-2021 by Bryan Biedenkapp N2PLL
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "Defines.h"
#include "p25/P25Defines.h"
#include "p25/data/DataBlock.h"
#include "edac/CRC.h"
#include "Log.h"
#include "Utils.h"
using namespace p25::data;
using namespace p25;
#include <cstdio>
#include <cassert>
#include <cstring>
// ---------------------------------------------------------------------------
// Public Class Members
// ---------------------------------------------------------------------------
/// <summary>
/// Initializes a new instance of the DataBlock class.
/// </summary>
DataBlock::DataBlock() :
m_confirmed(false),
m_serialNo(0U),
m_lastBlock(false),
m_llId(0U),
m_sap(0U),
m_trellis(),
m_fmt(PDU_FMT_CONFIRMED),
m_headerSap(0U),
m_data(NULL)
{
m_data = new uint8_t[P25_PDU_CONFIRMED_DATA_LENGTH_BYTES];
}
/// <summary>
/// Finalizes a instance of the DataBlock class.
/// </summary>
DataBlock::~DataBlock()
{
delete[] m_data;
}
/// <summary>
/// Decodes P25 PDU data block.
/// </summary>
/// <param name="data"></param>
/// <param name="header">Instance of the DataHeader class.</param>
/// <returns>True, if data block was decoded, otherwise false.</returns>
bool DataBlock::decode(const uint8_t* data, const DataHeader header)
{
assert(data != NULL);
assert(m_data != NULL);
uint8_t buffer[P25_PDU_CONFIRMED_LENGTH_BYTES];
::memset(buffer, 0x00U, P25_PDU_CONFIRMED_LENGTH_BYTES);
m_fmt = header.getFormat();
m_headerSap = header.getSAP();
if (m_fmt == PDU_FMT_CONFIRMED) {
// decode 3/4 rate Trellis
try {
m_confirmed = true;
bool valid = m_trellis.decode34(data, buffer);
if (!valid) {
LogError(LOG_P25, "DataBlock::decode(), failed to decode Trellis 3/4 rate coding");
return false;
}
// determine the number of user data bytes
uint32_t count = P25_PDU_CONFIRMED_DATA_LENGTH_BYTES;
if ((m_serialNo == (header.getBlocksToFollow() - 1) && header.getBlocksToFollow() > 1) ||
(m_headerSap == PDU_SAP_EXT_ADDR && m_serialNo == 0U)) {
count = P25_PDU_CONFIRMED_DATA_LENGTH_BYTES - 4U;
m_lastBlock = true;
} else {
if (header.getBlocksToFollow() <= 1) {
m_lastBlock = true;
}
}
#if DEBUG_P25_PDU_DATA
Utils::dump(1U, "P25, DataBlock::decode(), PDU Confirmed Data Block", buffer, P25_PDU_CONFIRMED_LENGTH_BYTES);
#endif
m_serialNo = (buffer[0] & 0xFEU) >> 1; // Confirmed Data Serial No.
uint16_t crc = ((buffer[0] & 0x01U) << 8) + buffer[1]; // CRC-9 Check Sum
::memset(m_data, 0x00U, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES);
// if this is extended addressing and the first block decode the SAP and LLId
if (m_headerSap == PDU_SAP_EXT_ADDR && m_serialNo == 0U) {
m_sap = buffer[5U] & 0x3FU; // Service Access Point
m_llId = (buffer[2U] << 16) + (buffer[3U] << 8) + buffer[4U]; // Logical Link ID
::memcpy(m_data, buffer + 6U, count); // Payload Data
}
else {
::memcpy(m_data, buffer + 2U, count); // Payload Data
}
#if DEBUG_P25_PDU_DATA
Utils::dump(1U, "P25, DataBlock::decode(), Confirmed PDU Block Data", m_data, count);
#endif
// compute CRC-9 for the packet
uint16_t calculated = edac::CRC::crc9(buffer, 144U);
if (((crc ^ calculated) != 0) && ((crc ^ calculated) != 0x1FFU)) {
LogWarning(LOG_P25, "P25_DUID_PDU, fmt = $%02X, invalid crc = $%04X != $%04X (computed)", m_fmt, crc, calculated);
}
#if DEBUG_P25_PDU_DATA
LogDebug(LOG_P25, "P25_DUID_PDU, fmt = $%02X, crc = $%04X, calculated = $%04X", m_fmt, crc, calculated);
#endif
}
catch (...) {
Utils::dump(2U, "P25, decoding excepted with input data", data, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES);
return false;
}
}
else if ((m_fmt == PDU_FMT_UNCONFIRMED) || (m_fmt == PDU_FMT_RSP) || (m_fmt == PDU_FMT_AMBT)) {
// decode 3/4 rate Trellis
try {
m_confirmed = false;
bool valid = m_trellis.decode12(data, buffer);
if (!valid) {
LogError(LOG_P25, "DataBlock::decode(), failed to decode Trellis 1/2 rate coding");
return false;
}
::memset(m_data, 0x00U, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES);
#if DEBUG_P25_PDU_DATA
Utils::dump(1U, "P25, DataBlock::decode(), PDU Unconfirmed Data Block", buffer, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
#endif
::memcpy(m_data, buffer, P25_PDU_UNCONFIRMED_LENGTH_BYTES); // Payload Data
}
catch (...) {
Utils::dump(2U, "P25, decoding excepted with input data", data, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
return false;
}
}
else {
LogError(LOG_P25, "unknown FMT value in P25_DUID_PDU, fmt = $%02X", m_fmt);
}
return true;
}
/// <summary>
/// Encodes a P25 PDU data block.
/// </summary>
/// <param name="data">Buffer to encode data block to.</param>
void DataBlock::encode(uint8_t* data)
{
assert(data != NULL);
assert(m_data != NULL);
if ((m_fmt == PDU_FMT_CONFIRMED) || (m_fmt == PDU_FMT_RSP && m_confirmed)) {
uint8_t buffer[P25_PDU_CONFIRMED_LENGTH_BYTES];
::memset(buffer, 0x00U, P25_PDU_CONFIRMED_LENGTH_BYTES);
buffer[0U] = ((m_serialNo << 1) & 0xFEU); // Confirmed Data Serial No.
// if this is extended addressing and the first block decode the SAP and LLId
if (m_headerSap == PDU_SAP_EXT_ADDR && m_serialNo == 0U) {
buffer[5U] = m_sap & 0x3FU; // Service Access Point
buffer[2U] = (m_llId >> 16) & 0xFFU; // Logical Link ID
buffer[3U] = (m_llId >> 8) & 0xFFU;
buffer[4U] = (m_llId >> 0) & 0xFFU;
::memcpy(buffer + 6U, m_data, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES - 4U);
}
else {
::memcpy(buffer + 2U, m_data, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES);
}
uint16_t crc = edac::CRC::crc9(buffer, 144U);
buffer[0U] = buffer[0U] + ((crc >> 8) & 0x01U); // CRC-9 Check Sum (b8)
buffer[1U] = (crc & 0xFFU); // CRC-9 Check Sum (b0 - b7)
#if DEBUG_P25_PDU_DATA
Utils::dump(1U, "P25, DataBlock::encode(), PDU Confirmed Data Block", buffer, P25_PDU_CONFIRMED_LENGTH_BYTES);
#endif
m_trellis.encode34(buffer, data);
}
else if ((m_fmt == PDU_FMT_UNCONFIRMED) || (m_fmt == PDU_FMT_RSP && !m_confirmed) || (m_fmt == PDU_FMT_AMBT)) {
uint8_t buffer[P25_PDU_UNCONFIRMED_LENGTH_BYTES];
::memset(buffer, 0x00U, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
::memcpy(buffer, m_data, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
#if DEBUG_P25_PDU_DATA
Utils::dump(1U, "P25, DataBlock::encode(), PDU Unconfirmed Data Block", buffer, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
#endif
m_trellis.encode12(buffer, data);
}
else {
LogError(LOG_P25, "unknown FMT value in P25_DUID_PDU, fmt = $%02X", m_fmt);
return;
}
}
/// <summary>Sets the data format.</summary>
/// <param name="fmt"></param>
void DataBlock::setFormat(const uint8_t fmt)
{
m_fmt = fmt;
}
/// <summary>Sets the data format from the data header.</summary>
/// <param name="header"></param>
void DataBlock::setFormat(const DataHeader header)
{
m_fmt = header.getFormat();
if (m_fmt == PDU_FMT_CONFIRMED) {
m_confirmed = true;
}
else {
m_confirmed = false;
}
}
/// <summary>Gets the data format.</summary>
/// <returns></returns>
uint8_t DataBlock::getFormat() const
{
return m_fmt;
}
/// <summary>Sets the raw data stored in the data block.</summary>
/// <param name="buffer"></param>
void DataBlock::setData(const uint8_t* buffer)
{
assert(buffer != NULL);
assert(m_data != NULL);
if ((m_fmt == PDU_FMT_CONFIRMED) || (m_fmt == PDU_FMT_RSP && m_confirmed)) {
::memcpy(m_data, buffer, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES);
}
else if ((m_fmt == PDU_FMT_UNCONFIRMED) || (m_fmt == PDU_FMT_RSP && !m_confirmed) || (m_fmt == PDU_FMT_AMBT)) {
::memcpy(m_data, buffer, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
}
else {
LogError(LOG_P25, "unknown FMT value in P25_DUID_PDU, fmt = $%02X", m_fmt);
}
}
/// <summary>Gets the raw data stored in the data block.</summary>
/// <returns></returns>
uint32_t DataBlock::getData(uint8_t* buffer) const
{
assert(buffer != NULL);
assert(m_data != NULL);
if ((m_fmt == PDU_FMT_CONFIRMED) || (m_fmt == PDU_FMT_RSP && m_confirmed)) {
::memcpy(buffer, m_data, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES);
return P25_PDU_CONFIRMED_DATA_LENGTH_BYTES;
}
else if ((m_fmt == PDU_FMT_UNCONFIRMED) || (m_fmt == PDU_FMT_RSP && !m_confirmed) || (m_fmt == PDU_FMT_AMBT)) {
::memcpy(buffer, m_data, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
return P25_PDU_UNCONFIRMED_LENGTH_BYTES;
}
else {
LogError(LOG_P25, "unknown FMT value in P25_DUID_PDU, fmt = $%02X", m_fmt);
return 0U;
}
}
// ---------------------------------------------------------------------------
// Private Class Members
// ---------------------------------------------------------------------------
/// <summary>
///
/// </summary>
/// <param name="buffer"></param>
uint16_t DataBlock::crc9()
{
assert(m_data != NULL);
uint16_t crc = 0x00U;
/*
edac::CRC::tmp_bit_cnt = 135U;
edac::CRC::crc9(&crc, m_serialNo, 7U);
for (uint8_t i = 0; i < P25_PDU_CONFIRMED_DATA_LENGTH_BYTES; i++) {
edac::CRC::crc9(&crc, m_data[i], 8U);
}
edac::CRC::crc9Finish(&crc, 8U);
crc = ~crc;
crc &= 0x01FFU;
crc ^= 0x01FFU;
#if DEBUG_P25_PDU_DATA
LogDebug(LOG_P25, "DataBlock::crc9(), crc = $%03X", crc);
#endif
*/
return crc;
}
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