MMDVMHost-Private/M17Network.cpp

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/*
* Copyright (C) 2020,2021 by Jonathan Naylor G4KLX
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*
* 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 "M17Network.h"
#include "M17Defines.h"
#include "M17Utils.h"
#include "Defines.h"
#include "Utils.h"
#include "Log.h"
#include <cstdio>
#include <cassert>
#include <cstring>
const unsigned int BUFFER_LENGTH = 200U;
CM17Network::CM17Network(const std::string& localAddress, unsigned short localPort, const std::string& gatewayAddress, unsigned short gatewayPort, bool debug) :
m_socket(localAddress, localPort),
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m_addr(),
m_addrLen(0U),
m_debug(debug),
m_enabled(false),
m_outId(0U),
m_inId(0U),
m_buffer(1000U, "M17 Network"),
m_random(),
m_timer(1000U, 5U)
{
if (CUDPSocket::lookup(gatewayAddress, gatewayPort, m_addr, m_addrLen) != 0) {
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m_addrLen = 0U;
return;
}
std::random_device rd;
std::mt19937 mt(rd());
m_random = mt;
}
CM17Network::~CM17Network()
{
}
bool CM17Network::open()
{
if (m_addrLen == 0U) {
LogError("M17, unable to resolve the gateway address");
return false;
}
LogMessage("Opening M17 network connection");
bool ret = m_socket.open(m_addr);
if (ret) {
m_timer.start();
return true;
} else {
return false;
}
}
bool CM17Network::write(const unsigned char* data)
{
if (m_addrLen == 0U)
return false;
assert(data != NULL);
unsigned char buffer[100U];
buffer[0U] = 'M';
buffer[1U] = '1';
buffer[2U] = '7';
buffer[3U] = ' ';
// Create a random id for this transmission if needed
if (m_outId == 0U) {
std::uniform_int_distribution<uint16_t> dist(0x0001, 0xFFFE);
m_outId = dist(m_random);
}
buffer[4U] = m_outId / 256U; // Unique session id
buffer[5U] = m_outId % 256U;
::memcpy(buffer + 6U, data, 46U);
// Dummy CRC
buffer[52U] = 0x00U;
buffer[53U] = 0x00U;
if (m_debug)
CUtils::dump(1U, "M17 data transmitted", buffer, 54U);
return m_socket.write(buffer, 54U, m_addr, m_addrLen);
}
void CM17Network::clock(unsigned int ms)
{
m_timer.clock(ms);
if (m_timer.isRunning() && m_timer.hasExpired()) {
sendPing();
m_timer.start();
}
unsigned char buffer[BUFFER_LENGTH];
sockaddr_storage address;
unsigned int addrLen;
int length = m_socket.read(buffer, BUFFER_LENGTH, address, addrLen);
if (length <= 0)
return;
if (!CUDPSocket::match(m_addr, address)) {
LogMessage("M17, packet received from an invalid source");
return;
}
if (m_debug)
CUtils::dump(1U, "M17 Network Data Received", buffer, length);
if (!m_enabled)
return;
if (::memcmp(buffer + 0U, "PING", 4U) == 0)
return;
if (::memcmp(buffer + 0U, "M17 ", 4U) != 0) {
CUtils::dump(2U, "M17, received unknown packet", buffer, length);
return;
}
uint16_t id = (buffer[4U] << 8) + (buffer[5U] << 0);
if (m_inId == 0U) {
m_inId = id;
} else {
if (id != m_inId)
return;
}
unsigned char c = length - 6U;
m_buffer.addData(&c, 1U);
m_buffer.addData(buffer + 6U, length - 6U);
}
bool CM17Network::read(unsigned char* data)
{
assert(data != NULL);
if (m_buffer.isEmpty())
return false;
unsigned char c = 0U;
m_buffer.getData(&c, 1U);
m_buffer.getData(data, c);
return true;
}
void CM17Network::close()
{
m_socket.close();
LogMessage("Closing M17 network connection");
}
void CM17Network::reset()
{
m_outId = 0U;
m_inId = 0U;
}
void CM17Network::enable(bool enabled)
{
if (!enabled && m_enabled)
m_buffer.clear();
m_enabled = enabled;
}
void CM17Network::sendPing()
{
unsigned char buffer[5U];
buffer[0U] = 'P';
buffer[1U] = 'I';
buffer[2U] = 'N';
buffer[3U] = 'G';
if (m_debug)
CUtils::dump(1U, "M17 data transmitted", buffer, 4U);
m_socket.write(buffer, 4U, m_addr, m_addrLen);
}