Handle network late entry properly.

Author: g4klx

NXDNControl.cpp

@@ -62,7 +62,9 @@ m_rfErrs(0U),
 m_rfBits(1U),
 m_rfLastLICH(),
 m_rfLayer3(),
+m_netLayer3(),
 m_rfMask(0x00U),
+m_netMask(0x00U),
 m_rssiMapper(rssiMapper),
 m_rssi(0U),
 m_maxRSSI(0U),
@@ -646,6 +648,9 @@ void CNXDNControl::writeEndNet()
 {
 	m_netState = RS_NET_IDLE;
 
+	m_netMask = 0x00U;
+	m_netLayer3.reset();
+
 	m_netTimeoutTimer.stop();
 	m_networkWatchdog.stop();
 	m_packetTimer.stop();
@@ -774,8 +779,44 @@ void CNXDNControl::writeNetwork()
 			m_netFrames++;
 			CUtils::dump(2U, "NXDN, interesting non superblock network frame", netData, 33U);
 		}
-	} else if (m_netState == RS_NET_IDLE) {
+	} else {
 		if (m_netState == RS_NET_IDLE) {
+			unsigned char structure = (netData[1U] >> 6) & 0x03U;
+			switch (structure) {
+			case NXDN_SR_1_4:
+				m_netLayer3.decode(netData + 2U, 18U, 0U);
+				if (m_netLayer3.getMessageType() == NXDN_MESSAGE_TYPE_VCALL)
+					m_netMask = 0x01U;
+				else
+					m_netMask = 0x00U;
+				break;
+			case NXDN_SR_2_4:
+				m_netMask |= 0x02U;
+				m_netLayer3.decode(netData + 2U, 18U, 18U);
+				break;
+			case NXDN_SR_3_4:
+				m_netMask |= 0x04U;
+				m_netLayer3.decode(netData + 2U, 18U, 36U);
+				break;
+			case NXDN_SR_4_4:
+				m_netMask |= 0x08U;
+				m_netLayer3.decode(netData + 2U, 18U, 54U);
+				break;
+			default:
+				break;
+			}
+
+			if (m_netMask != 0x0FU)
+				return;
+
+			unsigned char type = m_netLayer3.getMessageType();
+			if (type != NXDN_MESSAGE_TYPE_VCALL)
+				return;
+
+			unsigned short srcId = m_netLayer3.getSourceUnitId();
+			unsigned short dstId = m_netLayer3.getDestinationGroupId();
+			bool grp             = m_netLayer3.getIsGroup();
+
 			std::string source = m_lookup->find(srcId);
 			LogMessage("NXDN, received network transmission from %s to %s%u", source.c_str(), grp ? "TG " : "", dstId);
 			m_display->writeNXDN(source.c_str(), grp, dstId, "N");
@@ -784,10 +825,45 @@ void CNXDNControl::writeNetwork()
 			m_packetTimer.start();
 			m_elapsed.start();
 			m_netState  = RS_NET_AUDIO;
-			m_netFrames = 0U;
+			m_netFrames = 1U;
 			m_netLost   = 0U;
+
+			// Create a dummy start message
+			unsigned char start[NXDN_FRAME_LENGTH_BYTES + 2U];
+
+			start[0U] = TAG_DATA;
+			start[1U] = 0x00U;
+
+			// Generate the sync
+			CSync::addNXDNSync(start + 2U);
+
+			// Generate the LICH
+			CNXDNLICH lich;
+			lich.setRFCT(NXDN_LICH_RFCT_RDCH);
+			lich.setFCT(NXDN_LICH_USC_SACCH_NS);
+			lich.setOption(NXDN_LICH_STEAL_FACCH);
+			lich.setDirection(m_remoteGateway ? NXDN_LICH_DIRECTION_INBOUND : NXDN_LICH_DIRECTION_OUTBOUND);
+			lich.encode(start + 2U);
+
+			CNXDNSACCH sacch;
+			sacch.setRAN(m_ran);
+			sacch.setStructure(NXDN_SR_SINGLE);
+			sacch.setData(SACCH_IDLE);
+			sacch.encode(start + 2U);
+
+			unsigned char message[22U];
+			m_netLayer3.getData(message);
+
+			CNXDNFACCH1 facch;
+			facch.setData(message);
+			facch.encode(start + 2U, NXDN_FSW_LENGTH_BITS + NXDN_LICH_LENGTH_BITS + NXDN_SACCH_LENGTH_BITS);
+			facch.encode(start + 2U, NXDN_FSW_LENGTH_BITS + NXDN_LICH_LENGTH_BITS + NXDN_SACCH_LENGTH_BITS + NXDN_FACCH1_LENGTH_BITS);
+
+			scrambler(start + 2U);
+
+			writeQueueNet(start);
 		}
-	} else {
+
 		m_netFrames++;
 
 		data[0U] = TAG_DATA;

NXDNControl.h

@@ -69,7 +69,9 @@ class CNXDNControl {
 	unsigned int               m_rfBits;
 	CNXDNLICH                  m_rfLastLICH;
 	CNXDNLayer3                m_rfLayer3;
+	CNXDNLayer3                m_netLayer3;
 	unsigned char              m_rfMask;
+	unsigned char              m_netMask;
 	CRSSIInterpolator*         m_rssiMapper;
 	unsigned char              m_rssi;
 	unsigned char              m_maxRSSI;