MMDVMHost-Private/YSFControl.cpp

/*
 *	Copyright (C) 2015,2016,2017 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; version 2 of the License.
 *
 *	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.
 */

#include "YSFControl.h"
#include "YSFFICH.h"
#include "Utils.h"
#include "Sync.h"
#include "Log.h"

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

// #define	DUMP_YSF

CYSFControl::CYSFControl(const std::string& callsign, CYSFNetwork* network, CDisplay* display, unsigned int timeout, bool duplex, bool remoteGateway, CRSSIInterpolator* rssiMapper) :
m_callsign(NULL),
m_network(network),
m_display(display),
m_duplex(duplex),
m_remoteGateway(remoteGateway),
m_queue(5000U, "YSF Control"),
m_rfState(RS_RF_LISTENING),
m_netState(RS_NET_IDLE),
m_rfTimeoutTimer(1000U, timeout),
m_netTimeoutTimer(1000U, timeout),
m_packetTimer(1000U, 0U, 200U),
m_networkWatchdog(1000U, 0U, 1500U),
m_elapsed(),
m_rfFrames(0U),
m_netFrames(0U),
m_netLost(0U),
m_rfErrs(0U),
m_rfBits(1U),
m_netErrs(0U),
m_netBits(1U),
m_rfSource(NULL),
m_rfDest(NULL),
m_netSource(NULL),
m_netDest(NULL),
m_lastFrame(NULL),
m_lastFrameValid(false),
m_lastMode(YSF_DT_VOICE_FR_MODE),
m_lastMR(YSF_MR_NOT_BUSY),
m_netN(0U),
m_rfPayload(),
m_netPayload(),
m_rssiMapper(rssiMapper),
m_rssi(0U),
m_maxRSSI(0U),
m_minRSSI(0U),
m_aveRSSI(0U),
m_rssiCount(0U),
m_fp(NULL)
{
	assert(display != NULL);
	assert(rssiMapper != NULL);

	m_rfPayload.setUplink(callsign);
	m_rfPayload.setDownlink(callsign);

	m_netPayload.setDownlink(callsign);

	m_netSource = new unsigned char[YSF_CALLSIGN_LENGTH];
	m_netDest   = new unsigned char[YSF_CALLSIGN_LENGTH];

	m_lastFrame = new unsigned char[YSF_FRAME_LENGTH_BYTES + 2U];

	m_callsign = new unsigned char[YSF_CALLSIGN_LENGTH];

	std::string node = callsign;
	node.resize(YSF_CALLSIGN_LENGTH, ' ');

	for (unsigned int i = 0U; i < YSF_CALLSIGN_LENGTH; i++)
		m_callsign[i] = node.at(i);
}

CYSFControl::~CYSFControl()
{
	delete[] m_netSource;
	delete[] m_netDest;
	delete[] m_lastFrame;
	delete[] m_callsign;
}

bool CYSFControl::writeModem(unsigned char *data, unsigned int len)
{
	assert(data != NULL);

	unsigned char type = data[0U];

	if (type == TAG_LOST && m_rfState == RS_RF_AUDIO) {
		if (m_rssi != 0U)
			LogMessage("YSF, transmission lost, %.1f seconds, BER: %.1f%%, RSSI: -%u/-%u/-%u dBm", float(m_rfFrames) / 10.0F, float(m_rfErrs * 100U) / float(m_rfBits), m_minRSSI, m_maxRSSI, m_aveRSSI / m_rssiCount);
		else
			LogMessage("YSF, transmission lost, %.1f seconds, BER: %.1f%%", float(m_rfFrames) / 10.0F, float(m_rfErrs * 100U) / float(m_rfBits));
		writeEndRF();
		return false;
	}

	if (type == TAG_LOST)
		return false;

	// Have we got RSSI bytes on the end?
	if (len == (YSF_FRAME_LENGTH_BYTES + 4U)) {
		uint16_t raw = 0U;
		raw |= (data[122U] << 8) & 0xFF00U;
		raw |= (data[123U] << 0) & 0x00FFU;

		// Convert the raw RSSI to dBm
		int rssi = m_rssiMapper->interpolate(raw);
		LogDebug("YSF, raw RSSI: %u, reported RSSI: %d dBm", raw, rssi);

		// RSSI is always reported as positive
		m_rssi = (rssi >= 0) ? rssi : -rssi;

		if (m_rssi > m_minRSSI)
			m_minRSSI = m_rssi;
		if (m_rssi < m_maxRSSI)
			m_maxRSSI = m_rssi;

		m_aveRSSI += m_rssi;
		m_rssiCount++;
	}

	CYSFFICH fich;
	bool valid = fich.decode(data + 2U);

	if (valid && m_rfState == RS_RF_LISTENING) {
		unsigned char fi = fich.getFI();
		if (fi == YSF_FI_TERMINATOR)
			return false;

		m_rfFrames = 0U;
		m_rfErrs = 0U;
		m_rfBits = 1U;
		m_rfTimeoutTimer.start();
		m_rfPayload.reset();
		m_rfState = RS_RF_AUDIO;

		m_minRSSI = m_rssi;
		m_maxRSSI = m_rssi;
		m_aveRSSI = m_rssi;
		m_rssiCount = 1U;
#if defined(DUMP_YSF)
		openFile();
#endif
	}

	if (m_rfState != RS_RF_AUDIO)
		return false;

	if (valid)
		m_lastMR = fich.getMR();

	// Stop repeater packets coming through, unless we're acting as a remote gateway
	if (m_remoteGateway) {
		if (m_lastMR != YSF_MR_BUSY)
			return false;
	} else {
		if (m_lastMR == YSF_MR_BUSY)
			return false;
	}

	unsigned char fi = fich.getFI();
	if (valid && fi == YSF_FI_HEADER) {
		CSync::addYSFSync(data + 2U);

		// LogDebug("YSF, FICH: FI: %u, DT: %u, FN: %u, FT: %u", fich.getFI(), fich.getDT(), fich.getFN(), fich.getFT());

		valid = m_rfPayload.processHeaderData(data + 2U);

		if (valid)
			m_rfSource = m_rfPayload.getSource();

		unsigned char cm = fich.getCM();
		if (cm == YSF_CM_GROUP) {
			m_rfDest = (unsigned char*)"ALL       ";
		} else {
			if (valid)
				m_rfDest = m_rfPayload.getDest();
		}

		if (m_rfSource != NULL && m_rfDest != NULL) {
			m_display->writeFusion((char*)m_rfSource, (char*)m_rfDest, "R", "          ");
			LogMessage("YSF, received RF header from %10.10s to %10.10s", m_rfSource, m_rfDest);
		} else if (m_rfSource == NULL && m_rfDest != NULL) {
			m_display->writeFusion("??????????", (char*)m_rfDest, "R", "          ");
			LogMessage("YSF, received RF header from ?????????? to %10.10s", m_rfDest);
		} else if (m_rfSource != NULL && m_rfDest == NULL) {
			m_display->writeFusion((char*)m_rfSource, "??????????", "R", "          ");
			LogMessage("YSF, received RF header from %10.10s to ??????????", m_rfSource);
		} else {
			m_display->writeFusion("??????????", "??????????", "R", "          ");
			LogMessage("YSF, received RF header from ?????????? to ??????????");
		}

		data[0U] = TAG_DATA;
		data[1U] = 0x00U;

		writeNetwork(data, m_rfFrames % 128U);

#if defined(DUMP_YSF)
		writeFile(data + 2U);
#endif

		if (m_duplex) {
			fich.setMR(m_remoteGateway ? YSF_MR_NOT_BUSY : YSF_MR_BUSY);
			fich.encode(data + 2U);
			writeQueueRF(data);
		}

		m_rfFrames++;

		m_display->writeFusionRSSI(m_rssi);
	} else if (valid && fi == YSF_FI_TERMINATOR) {
		CSync::addYSFSync(data + 2U);

		// LogDebug("YSF, FICH: FI: %u, DT: %u, FN: %u, FT: %u", fich.getFI(), fich.getDT(), fich.getFN(), fich.getFT());

		m_rfPayload.processHeaderData(data + 2U);

		data[0U] = TAG_EOT;
		data[1U] = 0x00U;

		writeNetwork(data, m_rfFrames % 128U);

#if defined(DUMP_YSF)
		writeFile(data + 2U);
#endif

		if (m_duplex) {
			fich.setMR(m_remoteGateway ? YSF_MR_NOT_BUSY : YSF_MR_BUSY);
			fich.encode(data + 2U);
			writeQueueRF(data);
		}

		m_rfFrames++;

		if (m_rssi != 0U)
			LogMessage("YSF, received RF end of transmission, %.1f seconds, BER: %.1f%%, RSSI: -%u/-%u/-%u dBm", float(m_rfFrames) / 10.0F, float(m_rfErrs * 100U) / float(m_rfBits), m_minRSSI, m_maxRSSI, m_aveRSSI / m_rssiCount);
		else
			LogMessage("YSF, received RF end of transmission, %.1f seconds, BER: %.1f%%", float(m_rfFrames) / 10.0F, float(m_rfErrs * 100U) / float(m_rfBits));

		writeEndRF();

		return false;
	} else if (valid) {
		CSync::addYSFSync(data + 2U);

		unsigned char bn = fich.getBN();
		unsigned char bt = fich.getBT();
		unsigned char fn = fich.getFN();
		unsigned char ft = fich.getFT();
		unsigned char dt = fich.getDT();

		// LogDebug("YSF, FICH: FI: %u, DT: %u, FN: %u, FT: %u", fich.getFI(), fich.getDT(), fich.getFN(), fich.getFT());

		switch (dt) {
		case YSF_DT_VD_MODE1: {
				valid = m_rfPayload.processVDMode1Data(data + 2U, fn);
				unsigned int errors = m_rfPayload.processVDMode1Audio(data + 2U);
				m_rfErrs += errors;
				m_rfBits += 235U;
				m_display->writeFusionBER(float(errors) / 2.35F);
				LogDebug("YSF, V/D Mode 1, seq %u, AMBE FEC %u/235 (%.1f%%)", m_rfFrames % 128, errors, float(errors) / 2.35F);
			}
			break;

		case YSF_DT_VD_MODE2: {
				valid = m_rfPayload.processVDMode2Data(data + 2U, fn);
				unsigned int errors = m_rfPayload.processVDMode2Audio(data + 2U);
				m_rfErrs += errors;
				m_rfBits += 135U;
				m_display->writeFusionBER(float(errors) / 1.35F);
				LogDebug("YSF, V/D Mode 2, seq %u, Repetition FEC %u/135 (%.1f%%)", m_rfFrames % 128, errors, float(errors) / 1.35F);
			}
			break;

		case YSF_DT_DATA_FR_MODE:
			LogDebug("YSF, RF data FICH B=%u/%u F=%u/%u", bn, bt, fn, ft);
			valid = m_rfPayload.processDataFRModeData(data + 2U, fn);
			break;

		case YSF_DT_VOICE_FR_MODE:
			if (fn != 0U || ft != 1U) {
				// The first packet after the header is odd, don't try and regenerate it
				unsigned int errors = m_rfPayload.processVoiceFRModeAudio(data + 2U);
				m_rfErrs += errors;
				m_rfBits += 720U;
				m_display->writeFusionBER(float(errors) / 7.2F);
				LogDebug("YSF, V Mode 3, seq %u, AMBE FEC %u/720 (%.1f%%)", m_rfFrames % 128, errors, float(errors) / 7.2F);
			}
			valid = false;
			break;

		default:
			break;
		}

		bool change = false;

		if (m_rfDest == NULL) {
			unsigned char cm = fich.getCM();
			if (cm == YSF_CM_GROUP) {
				m_rfDest = (unsigned char*)"ALL       ";
				change = true;
			} else if (valid) {
				m_rfDest = m_rfPayload.getDest();
				if (m_rfDest != NULL)
					change = true;
			}
		}

		if (valid && m_rfSource == NULL) {
			m_rfSource = m_rfPayload.getSource();
			if (m_rfSource != NULL)
				change = true;
		}

		if (change) {
			if (m_rfSource != NULL && m_rfDest != NULL) {
				m_display->writeFusion((char*)m_rfSource, (char*)m_rfDest, "R", "          ");
				LogMessage("YSF, received RF data from %10.10s to %10.10s", m_rfSource, m_rfDest);
			}
			if (m_rfSource != NULL && m_rfDest == NULL) {
				m_display->writeFusion((char*)m_rfSource, "??????????", "R", "          ");
				LogMessage("YSF, received RF data from %10.10s to ??????????", m_rfSource);
			}
			if (m_rfSource == NULL && m_rfDest != NULL) {
				m_display->writeFusion("??????????", (char*)m_rfDest, "R", "          ");
				LogMessage("YSF, received RF data from ?????????? to %10.10s", m_rfDest);
			}
		}

		data[0U] = TAG_DATA;
		data[1U] = 0x00U;

		writeNetwork(data, m_rfFrames % 128U);

		if (m_duplex) {
			fich.setMR(m_remoteGateway ? YSF_MR_NOT_BUSY : YSF_MR_BUSY);
			fich.encode(data + 2U);
			writeQueueRF(data);
		}

#if defined(DUMP_YSF)
		writeFile(data + 2U);
#endif

		m_rfFrames++;

		m_display->writeFusionRSSI(m_rssi);
	} else {
		CSync::addYSFSync(data + 2U);

		data[0U] = TAG_DATA;
		data[1U] = 0x00U;

		writeNetwork(data, m_rfFrames % 128U);

		if (m_duplex)
			writeQueueRF(data);

#if defined(DUMP_YSF)
		writeFile(data + 2U);
#endif
		m_rfFrames++;

		m_display->writeFusionRSSI(m_rssi);
	}

	return true;
}

unsigned int CYSFControl::readModem(unsigned char* data)
{
	assert(data != NULL);

	if (m_queue.isEmpty())
		return 0U;

	unsigned char len = 0U;
	m_queue.getData(&len, 1U);

	m_queue.getData(data, len);

	return len;
}

void CYSFControl::writeEndRF()
{
	m_rfState = RS_RF_LISTENING;

	m_rfTimeoutTimer.stop();
	m_rfPayload.reset();

	// These variables are free'd by YSFPayload
	m_rfSource = NULL;
	m_rfDest = NULL;

	if (m_netState == RS_NET_IDLE) {
		m_display->clearFusion();

		if (m_network != NULL)
			m_network->reset();
	}

#if defined(DUMP_YSF)
	closeFile();
#endif
}

void CYSFControl::writeEndNet()
{
	m_netState = RS_NET_IDLE;

	m_netTimeoutTimer.stop();
	m_networkWatchdog.stop();
	m_packetTimer.stop();

	m_lastFrameValid = false;

	m_netPayload.reset();

	m_display->clearFusion();

	if (m_network != NULL)
		m_network->reset();
}

void CYSFControl::writeNetwork()
{
	unsigned char data[200U];
	unsigned int length = m_network->read(data);
	if (length == 0U)
		return;

	if (m_rfState != RS_RF_LISTENING && m_netState == RS_NET_IDLE)
		return;

	m_networkWatchdog.start();

	bool gateway = ::memcmp(data + 4U, m_callsign, YSF_CALLSIGN_LENGTH) == 0;

	unsigned char n = (data[34U] & 0xFEU) >> 1;
	bool end = (data[34U] & 0x01U) == 0x01U;

	if (!m_netTimeoutTimer.isRunning()) {
		if (end)
			return;

		if (::memcmp(data + 14U, "          ", YSF_CALLSIGN_LENGTH) != 0)
			::memcpy(m_netSource, data + 14U, YSF_CALLSIGN_LENGTH);
		else
			::memcpy(m_netSource, "??????????", YSF_CALLSIGN_LENGTH);

		if (::memcmp(data + 24U, "          ", YSF_CALLSIGN_LENGTH) != 0)
			::memcpy(m_netDest, data + 24U, YSF_CALLSIGN_LENGTH);
		else
			::memcpy(m_netDest, "??????????", YSF_CALLSIGN_LENGTH);

		m_display->writeFusion((char*)m_netSource, (char*)m_netDest, "N", (char*)(data + 4U));
		LogMessage("YSF, received network data from %10.10s to %10.10s at %10.10s", m_netSource, m_netDest, data + 4U);

		m_netTimeoutTimer.start();
		m_netPayload.reset();
		m_packetTimer.start();
		m_elapsed.start();
		m_lastFrameValid = false;
		m_netState  = RS_NET_AUDIO;
		m_netFrames = 0U;
		m_netLost   = 0U;
		m_netErrs   = 0U;
		m_netBits   = 1U;
		m_netN      = 0U;
	} else {
		// Check for duplicate frames, if we can
		if (m_netN == n)
			return;

		bool changed = false;

		if (::memcmp(data + 14U, "          ", YSF_CALLSIGN_LENGTH) != 0 && ::memcmp(m_netSource, "??????????", YSF_CALLSIGN_LENGTH) == 0) {
			::memcpy(m_netSource, data + 14U, YSF_CALLSIGN_LENGTH);
			changed = true;
		}

		if (::memcmp(data + 24U, "          ", YSF_CALLSIGN_LENGTH) != 0 && ::memcmp(m_netDest, "??????????", YSF_CALLSIGN_LENGTH) == 0) {
			::memcpy(m_netDest, data + 24U, YSF_CALLSIGN_LENGTH);
			changed = true;
		}

		if (changed) {
			m_display->writeFusion((char*)m_netSource, (char*)m_netDest, "N", (char*)(data + 4U));
			LogMessage("YSF, received network data from %10.10s to %10.10s at %10.10s", m_netSource, m_netDest, data + 4U);
		}
	}

	data[33U] = end ? TAG_EOT : TAG_DATA;
	data[34U] = 0x00U;

	// bool send = true;

	CYSFFICH fich;
	bool valid = fich.decode(data + 35U);
	if (valid) {
		unsigned char bn = fich.getBN();
		unsigned char bt = fich.getBT();
		unsigned char dt = fich.getDT();
		unsigned char fn = fich.getFN();
		unsigned char ft = fich.getFT();
		unsigned char fi = fich.getFI();

		fich.setVoIP(true);
		fich.setMR(m_remoteGateway ? YSF_MR_NOT_BUSY : YSF_MR_BUSY);
		fich.encode(data + 35U);

		m_lastMode = dt;

		// Set the downlink callsign
		switch (fi) {
		case YSF_FI_HEADER:
		case YSF_FI_TERMINATOR:
			m_netPayload.processHeaderData(data + 35U);
			break;

		case YSF_FI_COMMUNICATIONS:
			switch (dt) {
			case YSF_DT_VD_MODE1: {
					m_netPayload.processVDMode1Data(data + 35U, fn, gateway);
					unsigned int errors = m_netPayload.processVDMode1Audio(data + 35U);
					// send = insertSilence(data + 33U, n);
					// if (send) {
						m_netErrs += errors;
						m_netBits += 235U;
					// }
				}
				break;

			case YSF_DT_VD_MODE2: {
					m_netPayload.processVDMode2Data(data + 35U, fn, gateway);
					unsigned int errors = m_netPayload.processVDMode2Audio(data + 35U);
					// send = insertSilence(data + 33U, n);
					// if (send) {
						m_netErrs += errors;
						m_netBits += 135U;
					// }
				}
				break;

			case YSF_DT_DATA_FR_MODE:
				m_netPayload.processDataFRModeData(data + 35U, fn, gateway);
				break;

			case YSF_DT_VOICE_FR_MODE:
				if (fn != 0U || ft != 1U) {
					// The first packet after the header is odd, don't try and regenerate it
					unsigned int errors = m_netPayload.processVoiceFRModeAudio(data + 35U);
					// send = insertSilence(data + 33U, n);
					// if (send) {
						m_netErrs += errors;
						m_netBits += 720U;
					// }
				}
				break;

			default:
				break;
			}
			break;

		default:
			break;
		}
	} else {
		// send = insertSilence(data + 33U, n);
	}

	// if (send) {
		writeQueueNet(data + 33U);
		m_packetTimer.start();
		m_netFrames++;
		m_netN = n;
	// }

	if (end) {
		LogMessage("YSF, received network end of transmission, %.1f seconds, %u%% packet loss, BER: %.1f%%", float(m_netFrames) / 10.0F, (m_netLost * 100U) / m_netFrames, float(m_netErrs * 100U) / float(m_netBits));
		writeEndNet();
	}
}

void CYSFControl::clock(unsigned int ms)
{
	if (m_network != NULL)
		writeNetwork();

	m_rfTimeoutTimer.clock(ms);
	m_netTimeoutTimer.clock(ms);

	if (m_netState == RS_NET_AUDIO) {
		m_networkWatchdog.clock(ms);

		if (m_networkWatchdog.hasExpired()) {
			LogMessage("YSF, network watchdog has expired, %.1f seconds, %u%% packet loss, BER: %.1f%%", float(m_netFrames) / 10.0F, (m_netLost * 100U) / m_netFrames, float(m_netErrs * 100U) / float(m_netBits));
			writeEndNet();
		}
	}

	/*
	if (m_netState == RS_NET_AUDIO) {
		m_packetTimer.clock(ms);

		if (m_packetTimer.isRunning() && m_packetTimer.hasExpired()) {
			unsigned int elapsed = m_elapsed.elapsed();
			unsigned int frames = elapsed / YSF_FRAME_TIME;

			if (frames > m_netFrames) {
				unsigned int count = frames - m_netFrames;
				if (count > 2U) {
					LogDebug("YSF, lost audio for 200ms filling in, elapsed: %ums, expected: %u, received: %u", elapsed, frames, m_netFrames);
					insertSilence(count - 1U);
				}
			}

			m_packetTimer.start();
		}
	}
	*/
}

void CYSFControl::writeQueueRF(const unsigned char *data)
{
	assert(data != NULL);

	if (m_netState != RS_NET_IDLE)
		return;

	if (m_rfTimeoutTimer.isRunning() && m_rfTimeoutTimer.hasExpired())
		return;

	unsigned char len = YSF_FRAME_LENGTH_BYTES + 2U;

	unsigned int space = m_queue.freeSpace();
	if (space < (len + 1U)) {
		LogError("YSF, overflow in the System Fusion RF queue");
		return;
	}

	m_queue.addData(&len, 1U);

	m_queue.addData(data, len);
}

void CYSFControl::writeQueueNet(const unsigned char *data)
{
	assert(data != NULL);

	if (m_netTimeoutTimer.isRunning() && m_netTimeoutTimer.hasExpired())
		return;

	unsigned char len = YSF_FRAME_LENGTH_BYTES + 2U;

	unsigned int space = m_queue.freeSpace();
	if (space < (len + 1U)) {
		LogError("YSF, overflow in the System Fusion RF queue");
		return;
	}

	m_queue.addData(&len, 1U);

	m_queue.addData(data, len);
}

void CYSFControl::writeNetwork(const unsigned char *data, unsigned int count)
{
	assert(data != NULL);

	if (m_network == NULL)
		return;

	if (m_rfTimeoutTimer.isRunning() && m_rfTimeoutTimer.hasExpired())
		return;

	m_network->write(m_rfSource, m_rfDest, data + 2U, count, data[0U] == TAG_EOT);
}

bool CYSFControl::openFile()
{
	if (m_fp != NULL)
		return true;

	time_t t;
	::time(&t);

	struct tm* tm = ::localtime(&t);

	char name[100U];
	::sprintf(name, "YSF_%04d%02d%02d_%02d%02d%02d.ambe", tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);

	m_fp = ::fopen(name, "wb");
	if (m_fp == NULL)
		return false;

	::fwrite("YSF", 1U, 3U, m_fp);

	return true;
}

bool CYSFControl::writeFile(const unsigned char* data)
{
	if (m_fp == NULL)
		return false;

	::fwrite(data, 1U, YSF_FRAME_LENGTH_BYTES, m_fp);

	return true;
}

void CYSFControl::closeFile()
{
	if (m_fp != NULL) {
		::fclose(m_fp);
		m_fp = NULL;
	}
}

bool CYSFControl::insertSilence(const unsigned char* data, unsigned char n)
{
	assert(data != NULL);

	// Check to see if we have any spaces to fill?
	unsigned char newN = (m_netN + 1U) % 128U;
	if (newN == n) {
		// Just copy the data, nothing else to do here
		::memcpy(m_lastFrame, data, YSF_FRAME_LENGTH_BYTES + 2U);
		m_lastFrameValid = true;
		return true;
	}

	LogDebug("YSF, current=%u last=%u", n, m_netN);

	unsigned int count;
	if (n > newN)
		count = n - newN;
	else
		count = (128U + n) - newN;

	if (count >= 4U) {
		LogDebug("YSF, frame is out of range, count = %u", count);
		return false;
	}

	insertSilence(count);

	::memcpy(m_lastFrame, data, YSF_FRAME_LENGTH_BYTES + 2U);
	m_lastFrameValid = true;

	return true;
}

void CYSFControl::insertSilence(unsigned int count)
{
	// We can't meaningfully create "silent" data
	if (m_lastMode == YSF_DT_DATA_FR_MODE)
		return;

	LogDebug("YSF, insert %u frames", count);

	unsigned char n = (m_netN + 1U) % 128U;

	for (unsigned int i = 0U; i < count; i++) {
		writeQueueNet(m_lastFrame);

		m_netN = n;

		m_netFrames++;
		m_netLost++;

		n = (n + 1U) % 128U;
	}

	LogDebug("YSF, last=%u", m_netN);
}