FMNetwork.cpp

/*
 *   Copyright (C) 2020,2021 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 "FMNetwork.h"
#include "Defines.h"
#include "Utils.h"
#include "Log.h"

#include <cstdio>
#include <cassert>
#include <cstring>

const unsigned int BUFFER_LENGTH = 1500U;

CFMNetwork::CFMNetwork(const std::string& callsign, const std::string& protocol, const std::string& localAddress, unsigned short localPort, const std::string& gatewayAddress, unsigned short gatewayPort, bool debug) :
m_callsign(callsign),
m_protocol(FMNP_USRP),
m_socket(localAddress, localPort),
m_addr(),
m_addrLen(0U),
m_debug(debug),
m_enabled(false),
m_buffer(2000U, "FM Network"),
m_seqNo(0U)
{
	assert(!callsign.empty());
	assert(gatewayPort > 0U);
	assert(!gatewayAddress.empty());

	if (CUDPSocket::lookup(gatewayAddress, gatewayPort, m_addr, m_addrLen) != 0)
		m_addrLen = 0U;

	// Remove any trailing letters in the callsign
	size_t pos = callsign.find_first_of(' ');
	if (pos != std::string::npos)
		m_callsign = callsign.substr(0U, pos);

	// if (protocol == "USRP")
	//	m_protocol = FMNP_USRP;
}

CFMNetwork::~CFMNetwork()
{
}

bool CFMNetwork::open()
{
	if (m_addrLen == 0U) {
		LogError("Unable to resolve the address of the FM Gateway");
		return false;
	}

	LogMessage("Opening FM network connection");

	return m_socket.open(m_addr);
}

bool CFMNetwork::writeData(float* data, unsigned int nSamples)
{
	assert(data != NULL);
	assert(nSamples > 0U);

	if (m_seqNo == 0U) {
		bool ret = writeStart();
		if (!ret)
			return false;
	}

	unsigned char buffer[500U];
	::memset(buffer, 0x00U, 500U);

	unsigned int length = 0U;

	if (m_protocol == FMNP_USRP) {
		buffer[length++] = 'U';
		buffer[length++] = 'S';
		buffer[length++] = 'R';
		buffer[length++] = 'P';

		// Sequence number
		buffer[length++] = (m_seqNo >> 24) & 0xFFU;
		buffer[length++] = (m_seqNo >> 16) & 0xFFU;
		buffer[length++] = (m_seqNo >> 8)  & 0xFFU;
		buffer[length++] = (m_seqNo >> 0)  & 0xFFU;

		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		// PTT on
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x01U;

		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		// Type, 0 for audio
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
	}

	for (unsigned int i = 0U; i < nSamples; i++) {
		 short val = short(data[i] * 32767.0F + 0.5F);			// Changing audio format from float to S16LE

		buffer[length++] = (val >> 0) & 0xFFU;
		buffer[length++] = (val >> 8) & 0xFFU;
	}

	if (m_debug)
		CUtils::dump(1U, "FM Network Data Sent", buffer, length);

	m_seqNo++;

	return m_socket.write(buffer, length, m_addr, m_addrLen);
}

bool CFMNetwork::writeEnd()
{
	unsigned char buffer[500U];
	::memset(buffer, 0x00U, 500U);

	unsigned int length = 0U;

	if (m_protocol == FMNP_USRP) {
		buffer[length++] = 'U';
		buffer[length++] = 'S';
		buffer[length++] = 'R';
		buffer[length++] = 'P';

		// Sequence number
		buffer[length++] = (m_seqNo >> 24) & 0xFFU;
		buffer[length++] = (m_seqNo >> 16) & 0xFFU;
		buffer[length++] = (m_seqNo >> 8) & 0xFFU;
		buffer[length++] = (m_seqNo >> 0) & 0xFFU;

		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		// PTT off
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		// Type, 0 for audio
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		length += 320U;
	}

	m_seqNo = 0U;

	if (length > 0U) {
		if (m_debug)
			CUtils::dump(1U, "FM Network Data Sent", buffer, length);

		return m_socket.write(buffer, length, m_addr, m_addrLen);
	} else {
		return true;
	}
}

void CFMNetwork::clock(unsigned int ms)
{
	unsigned char buffer[BUFFER_LENGTH];

	sockaddr_storage addr;
	unsigned int addrlen;
	int length = m_socket.read(buffer, BUFFER_LENGTH, addr, addrlen);
	if (length <= 0)
		return;

	// Check if the data is for us
	if (!CUDPSocket::match(addr, m_addr)) {
		LogMessage("FM packet received from an invalid source");
		return;
	}

	if (!m_enabled)
		return;

	if (m_debug)
		CUtils::dump(1U, "FM Network Data Received", buffer, length);

	if (m_protocol == FMNP_USRP) {
		// Invalid packet type?
		if (::memcmp(buffer, "USRP", 4U) != 0)
			return;

		if (length < 32)
			return;

		// The type is a big-endian 4-byte integer
		unsigned int type = (buffer[20U] << 24) +
							(buffer[21U] << 16) +
							(buffer[22U] << 8)  +
							(buffer[23U] << 0);

		if (type == 0U)
			m_buffer.addData(buffer + 32U, length - 32U);
	}
}

unsigned int CFMNetwork::read(float* data, unsigned int nSamples)
{
	assert(data != NULL);
	assert(nSamples > 0U);

	unsigned int bytes = m_buffer.dataSize() / sizeof(unsigned short);
	if (bytes == 0U)
		return 0U;

	if (bytes < nSamples)
		nSamples = bytes;

	unsigned char buffer[1500U];
	m_buffer.getData(buffer, nSamples * sizeof(unsigned short));

	for (unsigned int i = 0U; i < nSamples; i++) {
		short val = ((buffer[i * 2U + 0U] & 0xFFU) << 0) + ((buffer[i * 2U + 1U] & 0xFFU) << 8);
		data[i] = float(val) / 65536.0F;
	}

	return nSamples;
}

void CFMNetwork::reset()
{
	m_buffer.clear();
}

void CFMNetwork::close()
{
	m_socket.close();

	LogMessage("Closing FM network connection");
}

void CFMNetwork::enable(bool enabled)
{
	if (enabled && !m_enabled)
		reset();
	else if (!enabled && m_enabled)
		reset();

	m_enabled = enabled;
}

bool CFMNetwork::writeStart()
{
	unsigned char buffer[500U];
	::memset(buffer, 0x00U, 500U);

	unsigned int length = 0U;

	if (m_protocol == FMNP_USRP) {
		buffer[length++] = 'U';
		buffer[length++] = 'S';
		buffer[length++] = 'R';
		buffer[length++] = 'P';

		// Sequence number
		buffer[length++] = (m_seqNo >> 24) & 0xFFU;
		buffer[length++] = (m_seqNo >> 16) & 0xFFU;
		buffer[length++] = (m_seqNo >> 8) & 0xFFU;
		buffer[length++] = (m_seqNo >> 0) & 0xFFU;

		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		// PTT off
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		// Type, 2 for metadata
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x02U;

		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		// TLV TAG for Metadata
		buffer[length++] = 0x08U;

		// TLV Length
		buffer[length++] = 3U + 4U + 3U + 1U + 1U + m_callsign.size() + 1U;

		// DMR Id
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		// Rpt Id
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		// Talk Group
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;
		buffer[length++] = 0x00U;

		// Time Slot
		buffer[length++] = 0x00U;

		// Color Code
		buffer[length++] = 0x00U;

		// Callsign
		for (std::string::const_iterator it = m_callsign.cbegin(); it != m_callsign.cend(); ++it)
			buffer[length++] = *it;

		// End of Metadata
		buffer[length++] = 0x00U;

		length = 70U;
	}

	if (length > 0U) {
		if (m_debug)
			CUtils::dump(1U, "FM Network Data Sent", buffer, length);

		return m_socket.write(buffer, length, m_addr, m_addrLen);
	} else {
		return true;
	}
}