MMDVMHost-Private/AX25Network.cpp

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2020-12-15 16:21:07 +00:00
/*
* Copyright (C) 2020 by Jonathan Naylor G4KLX
*
* 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 "AX25Network.h"
#include "AX25Defines.h"
#include "Defines.h"
#include "Utils.h"
#include "Log.h"
#include <cstdio>
#include <cassert>
#include <cstring>
const unsigned int BUFFER_LENGTH = 500U;
CAX25Network::CAX25Network(const std::string& port, unsigned int speed, bool debug) :
m_serial(port, speed, false),
m_txData(NULL),
m_rxData(NULL),
m_rxLength(0U),
m_rxLastChar(0U),
m_debug(debug),
m_enabled(false)
{
assert(!port.empty());
assert(speed > 0U);
m_txData = new unsigned char[BUFFER_LENGTH];
m_rxData = new unsigned char[BUFFER_LENGTH];
}
CAX25Network::~CAX25Network()
{
delete[] m_txData;
delete[] m_rxData;
}
bool CAX25Network::open()
{
LogMessage("Opening AX25 network connection");
return m_serial.open();
}
bool CAX25Network::write(const unsigned char* data, unsigned int length)
{
assert(data != NULL);
if (!m_enabled)
return true;
unsigned int txLength = 0U;
m_txData[txLength++] = AX25_FEND;
m_txData[txLength++] = AX25_KISS_DATA;
for (unsigned int i = 0U; i < length; i++) {
unsigned char c = data[i];
switch (c) {
case AX25_FEND:
m_txData[txLength++] = AX25_FESC;
m_txData[txLength++] = AX25_TFEND;
break;
case AX25_FESC:
m_txData[txLength++] = AX25_FESC;
m_txData[txLength++] = AX25_TFESC;
break;
default:
m_txData[txLength++] = c;
break;
}
}
m_txData[txLength++] = AX25_FEND;
if (m_debug)
CUtils::dump(1U, "AX25 Network Data Sent", m_txData, txLength);
return m_serial.write(m_txData, txLength);
}
unsigned int CAX25Network::read(unsigned char* data, unsigned int length)
{
assert(data != NULL);
bool complete = false;
unsigned char c;
while (m_serial.read(&c, 1U) > 0) {
if (m_rxLength == 0U && c == AX25_FEND)
m_rxData[m_rxLength++] = c;
else if (m_rxLength > 0U)
m_rxData[m_rxLength++] = c;
if (m_rxLength > 1U && c == AX25_FEND) {
complete = true;
break;
}
}
if (!m_enabled)
return 0U;
if (!complete)
return 0U;
if (m_rxLength == 0U)
return 0U;
if (m_rxData[1U] != AX25_KISS_DATA) {
m_rxLength = 0U;
return 0U;
}
complete = false;
unsigned int dataLen = 0U;
for (unsigned int i = 2U; i < m_rxLength; i++) {
unsigned char c = m_rxData[i];
if (c == AX25_FEND) {
complete = true;
break;
} else if (c == AX25_TFEND && m_rxLastChar == AX25_FESC) {
data[dataLen++] = AX25_FEND;
} else if (c == AX25_TFESC && m_rxLastChar == AX25_FESC) {
data[dataLen++] = AX25_FESC;
} else {
data[dataLen++] = c;
}
m_rxLastChar = c;
}
if (!complete)
return 0U;
if (m_debug)
CUtils::dump(1U, "AX25 Network Data Received", m_rxData, m_rxLength);
m_rxLength = 0U;
m_rxLastChar = 0U;
return dataLen;
}
void CAX25Network::reset()
{
}
void CAX25Network::close()
{
m_serial.close();
LogMessage("Closing AX25 network connection");
}
void CAX25Network::enable(bool enabled)
{
m_enabled = enabled;
if (enabled != m_enabled) {
m_rxLastChar = 0U;
m_rxLength = 0U;
}
}