~whyclj/iec61850_forFoShanAES_Model.git

			@@ -1,754 +1,754 @@
			/*
			* Copyright 2011-17 Fraunhofer ISE, energy & meteo Systems GmbH and other contributors
			*
			* Licensed under the Apache License, Version 2.0 (the "License");
			* you may not use this file except in compliance with the License.
			* You may obtain a copy of the License at
			*
			* http://www.apache.org/licenses/LICENSE-2.0
			*
			* Unless required by applicable law or agreed to in writing, software
			* distributed under the License is distributed on an "AS IS" BASIS,
			* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
			* See the License for the specific language governing permissions and
			* limitations under the License.
			*
			*/
			package org.openmuc.jositransport;

			import java.io.BufferedInputStream;
			import java.io.BufferedOutputStream;
			import java.io.DataInputStream;
			import java.io.DataOutputStream;
			import java.io.EOFException;
			import java.io.IOException;
			import java.net.Socket;
			import java.net.SocketTimeoutException;
			import java.nio.ByteBuffer;
			import java.util.ArrayList;
			import java.util.List;
			import java.util.concurrent.TimeoutException;

			public final class TConnection {

			// private static final Logger logger = LoggerFactory.getLogger(TConnection.class);

			private final Socket socket;
			private final DataOutputStream os;
			private final DataInputStream is;
			private static Integer connectionCounter = 0;

			public byte[] tSelRemote = null;
			public byte[] tSelLocal = null;

			private int srcRef;
			private int dstRef;
			private int maxTPduSizeParam;
			private int maxTPduSize;
			private int messageTimeout;
			private int messageFragmentTimeout;

			private boolean closed = false;

			private final ServerThread serverThread;

			TConnection(Socket socket, int maxTPduSizeParam, int messageTimeout, int messageFragmentTimeout,
			ServerThread serverThread) throws IOException {
			if (maxTPduSizeParam < 7 \|\| maxTPduSizeParam > 16) {
			throw new RuntimeException("maxTPduSizeParam is incorrect");
			}
			this.socket = socket;
			os = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
			is = new DataInputStream(new BufferedInputStream(socket.getInputStream()));

			synchronized (socket) {
			connectionCounter++;
			connectionCounter %= 65520;
			if (connectionCounter == 0) {
			connectionCounter = 1; // some servers do not like srcRef 0
			}
			srcRef = connectionCounter;
			}

			this.messageTimeout = messageTimeout;
			this.messageFragmentTimeout = messageFragmentTimeout;
			this.maxTPduSizeParam = maxTPduSizeParam;
			maxTPduSize = ClientTSap.getMaxTPDUSize(maxTPduSizeParam);

			this.serverThread = serverThread;
			}

			/**
			* This function is called once a client has connected to the server. It listens for a Connection Request (CR). If
			* this is successful it replies afterwards with a Connection Confirm (CC). According to the norm a syntax error in
			* the CR should be followed by an ER. This implementation does not send an ER because it seems unnecessary.
			*
			* @throws IOException
			*/
			void listenForCR() throws IOException {

			socket.setSoTimeout(messageFragmentTimeout);

			byte myByte;
			int lengthIndicator;
			int parameterLength;

			//is.available();

			// start reading rfc 1006 header
			if (is.read() != 0x03) {
			throw new IOException();
			}
			if (is.read() != 0) {
			throw new IOException();
			}
			// read Packet length, but is not needed
			is.readShort();
			// reading rfc 1006 header finished

			lengthIndicator = is.read() & 0xff;
			// 0xe0 is the CR-Code
			if ((is.read() & 0xff) != 0xe0) {
			throw new IOException();
			}
			// DST-REF needs to be 0 in a CR packet
			if (is.readShort() != 0) {
			throw new IOException();
			}
			// read the srcRef which is the dstRef for this end-point
			dstRef = is.readShort() & 0xffff;
			// read class
			if ((is.read() & 0xff) != 0) {
			throw new IOException();
			}
			int variableBytesRead = 0;
			while (lengthIndicator > (6 + variableBytesRead)) {
			// read parameter code
			myByte = is.readByte();
			switch (myByte & 0xff) {
			case 0xc2:
			parameterLength = is.readByte() & 0xff;

			if (tSelLocal == null) {
			tSelLocal = new byte[parameterLength];
			is.readFully(tSelLocal);
			}
			else {
			if (parameterLength != tSelLocal.length) {
			throw new IOException("local T-SElECTOR is wrong.");
			}
			for (int i = 0; i < parameterLength; i++) {
			if ((tSelLocal[i] & 0xff) != is.read()) {
			throw new IOException("local T-SElECTOR is wrong.");
			}
			}
			}
			variableBytesRead += 2 + parameterLength;
			break;
			case 0xc1:
			parameterLength = is.readByte() & 0xff;

			if (tSelRemote == null) {
			tSelRemote = new byte[parameterLength];
			is.readFully(tSelRemote);
			}
			else {
			if (parameterLength != tSelRemote.length) {
			throw new IOException("remote T-SElECTOR is wrong.");
			}
			for (int i = 0; i < parameterLength; i++) {
			if ((tSelRemote[i] & 0xff) != is.read()) {
			throw new IOException("remote T-SElECTOR is wrong.");
			}
			}
			}
			variableBytesRead += 2 + parameterLength;
			break;

			case 0xc0:
			if ((is.readByte() & 0xff) != 1) {
			throw new IOException();
			}
			myByte = is.readByte();
			int newMaxTPDUSizeParam = (myByte & 0xff);
			if (newMaxTPDUSizeParam < 7 \|\| newMaxTPDUSizeParam > 16) {
			throw new IOException("maxTPDUSizeParam is out of bound");
			}
			else {
			if (newMaxTPDUSizeParam < maxTPduSizeParam) {
			maxTPduSizeParam = newMaxTPDUSizeParam;
			maxTPduSize = ClientTSap.getMaxTPDUSize(maxTPduSizeParam);
			}
			}
			variableBytesRead += 3;
			break;
			default:
			throw new IOException();
			}

			}

			// write RFC 1006 Header
			os.write(0x03);
			os.write(0x00);
			// write complete packet length

			int variableLength = 3;

			if (tSelLocal != null) {
			variableLength += 2 + tSelLocal.length;
			}
			if (tSelRemote != null) {
			variableLength += 2 + tSelRemote.length;
			}
			os.writeShort(4 + 7 + variableLength);

			// write connection request (CR) TPDU (§13.3)

			// write length indicator
			os.write(6 + variableLength);

			// write fixed part
			// write CC CDT
			os.write(0xd0);
			// write DST-REF
			os.writeShort(dstRef);
			// write SRC-REF
			os.writeShort(srcRef);
			// write class
			os.write(0);

			// write variable part
			if (tSelLocal != null) {
			os.write(0xc2);
			os.write(tSelLocal.length);
			os.write(tSelLocal);
			}

			if (tSelRemote != null) {
			os.write(0xc1);
			os.write(tSelRemote.length);
			os.write(tSelRemote);
			}
			// write proposed maximum TPDU Size
			os.write(0xc0);
			os.write(1);
			os.write(maxTPduSizeParam);

			os.flush();

			}

			/**
			* Starts a connection, sends a CR, waits for a CC and throws an IOException if not successful
			*
			* @throws IOException
			*/
			void startConnection() throws IOException {

			ByteBuffer bf = ByteBuffer.allocate(1024);

			// write RFC 1006 Header
			bf.put((byte) 0x03);
			bf.put((byte) 0x00);

			// write complete packet length
			int variableLength = 3;

			if (tSelLocal != null) {
			variableLength += 2 + tSelLocal.length;
			}
			if (tSelRemote != null) {
			variableLength += 2 + tSelRemote.length;
			}
			bf.putShort((short) (4 + 7 + variableLength));
			// writing RFC 1006 Header finished

			// write connection request (CR) TPDU (§13.3)

			// write length indicator
			bf.put((byte) (6 + variableLength));

			// write fixed part
			// write CR CDT
			bf.put((byte) 0xe0);
			// write DST-REF
			bf.put((byte) 0);
			bf.put((byte) 0);
			// write SRC-REF
			bf.putShort((short) srcRef);
			// write class
			bf.put((byte) 0);

			// write variable part
			// write proposed maximum TPDU Size
			bf.put((byte) 0xc0);
			bf.put((byte) 1);
			bf.put((byte) maxTPduSizeParam);

			if (tSelRemote != null) {
			bf.put((byte) 0xc2);
			bf.put((byte) tSelRemote.length);
			bf.put(tSelRemote);
			}
			if (tSelLocal != null) {
			bf.put((byte) 0xc1);
			bf.put((byte) tSelLocal.length);
			bf.put(tSelLocal);
			}

			bf.flip();
			byte[] outbyte = new byte[bf.limit()];
			bf.get(outbyte);
			os.write(outbyte);

			/*
			// write RFC 1006 Header
			os.write(0x03);
			os.write(0x00);

			// write complete packet length
			int variableLength = 3;

			if (tSelLocal != null) {
			variableLength += 2 + tSelLocal.length;
			}
			if (tSelRemote != null) {
			variableLength += 2 + tSelRemote.length;
			}
			os.writeShort(4 + 7 + variableLength);
			// writing RFC 1006 Header finished

			// write connection request (CR) TPDU (§13.3)

			// write length indicator
			os.write(6 + variableLength);

			// write fixed part
			// write CR CDT
			os.write(0xe0);
			// write DST-REF
			os.write(0);
			os.write(0);
			// write SRC-REF
			os.writeShort(srcRef);
			// write class
			os.write(0);

			// write variable part
			// write proposed maximum TPDU Size
			os.write(0xc0);
			os.write(1);
			os.write(maxTPduSizeParam);

			if (tSelRemote != null) {
			os.write(0xc2);
			os.write(tSelRemote.length);
			os.write(tSelRemote);
			}
			if (tSelLocal != null) {
			os.write(0xc1);
			os.write(tSelLocal.length);
			os.write(tSelLocal);
			}
			*/
			os.flush();

			socket.setSoTimeout(messageTimeout);

			byte myByte;
			int lengthIndicator;
			int parameterLength;
			//is.readFully(outbyte);
			//System.out.println("is.availabless() is : " + is.available());
			/*
			byte res_b = is.readByte();
			ByteBuffer is_bf = ByteBuffer.allocate(is.available()+1);
			is_bf.put(res_b);
			is.readFully(is_bf.array(), 1, is.available());
			*/
			if (is.readByte() != 0x03) {
			throw new IOException();
			}
			if (is.readByte() != 0) {
			throw new IOException();
			}
			//System.out.println("line 376 is.availabless() is : " + is.available());
			// read packet length, but is not needed
			is.readShort();
			lengthIndicator = is.readByte() & 0xff;
			if ((is.readByte() & 0xff) != 0xd0) {
			throw new IOException();
			}
			// read the dstRef which is the srcRef for this end-point
			is.readShort();
			// read the srcRef which is the dstRef for this end-point
			dstRef = is.readShort() & 0xffff;
			// read class
			if (is.readByte() != 0) {
			throw new IOException();
			}

			int variableBytesRead = 0;
			while (lengthIndicator > (6 + variableBytesRead)) {
			// read parameter code
			myByte = is.readByte();
			switch (myByte & 0xff) {

			case 0xc1:
			parameterLength = is.readByte() & 0xff;

			if (tSelLocal == null) {
			tSelLocal = new byte[parameterLength];
			is.readFully(tSelLocal);
			}
			else {
			for (int i = 0; i < parameterLength; i++) {
			//System.out.println("line 407 is.availabless() is : " + is.available());
			is.read();
			}
			}
			variableBytesRead += 2 + parameterLength;
			break;
			case 0xc2:
			parameterLength = is.readByte() & 0xff;

			if (tSelRemote == null) {
			tSelRemote = new byte[parameterLength];
			is.readFully(tSelRemote);
			}
			else {
			for (int i = 0; i < parameterLength; i++) {
			//System.out.println("line 422 is.availabless() is : " + is.available());
			is.read();
			}
			}
			variableBytesRead += 2 + parameterLength;
			break;

			case 0xc0:
			if (is.readByte() != 1) {
			throw new IOException("maxTPduSizeParam size is not equal to 1");
			}
			myByte = is.readByte();
			if ((myByte & 0xff) < 7 \|\| (myByte & 0xff) > maxTPduSizeParam) {
			throw new IOException("maxTPduSizeParam out of bound");
			}
			else {
			if ((myByte & 0xff) < maxTPduSizeParam) {
			maxTPduSizeParam = (myByte & 0xff);
			}
			}
			variableBytesRead += 4;
			break;
			default:
			throw new IOException();
			}

			}

			}

			public void send(List<byte[]> tsdus, List<Integer> offsets, List<Integer> lengths) throws IOException {

			int bytesLeft = 0;
			// for (byte[] tsdu : tsdus) {
			// bytesLeft += tsdu.length;
			// }
			for (int length : lengths) {
			bytesLeft += length;
			}
			int tsduOffset = 0;
			int byteArrayListIndex = 0;
			int numBytesToWrite;
			boolean lastPacket = false;
			int maxTSDUSize = maxTPduSize - 3;
			while (bytesLeft > 0) {

			if (bytesLeft > maxTSDUSize) {
			numBytesToWrite = maxTSDUSize;
			}
			else {
			numBytesToWrite = bytesLeft;
			lastPacket = true;
			}

			// --write RFC 1006 Header--
			// write Version
			os.write(0x03);
			// write reserved bits
			os.write(0);
			// write packet Length
			os.writeShort(numBytesToWrite + 7);

			// --write 8073 Header--
			// write Length Indicator of header
			os.write(0x02);
			// write TPDU Code for DT Data
			os.write(0xf0);
			// write TPDU-NR and EOT, TPDU-NR is always 0 for class 0
			if (lastPacket) {
			os.write(0x80);
			}
			else {
			os.write(0x00);
			}

			bytesLeft -= numBytesToWrite;
			while (numBytesToWrite > 0) {
			byte[] tsdu = tsdus.get(byteArrayListIndex);
			int length = lengths.get(byteArrayListIndex);
			int offset = offsets.get(byteArrayListIndex);

			int tsduWriteLength = length - tsduOffset;

			//System.out.println("send tsduWriteLength " + tsduWriteLength + " numBytesToWrite " + numBytesToWrite);

			if (numBytesToWrite > tsduWriteLength) {
			os.write(tsdu, offset + tsduOffset, tsduWriteLength);
			numBytesToWrite -= tsduWriteLength;
			tsduOffset = 0;
			byteArrayListIndex++;
			}
			else {
			os.write(tsdu, offset + tsduOffset, numBytesToWrite);
			if (numBytesToWrite == tsduWriteLength) {
			tsduOffset = 0;
			byteArrayListIndex++;
			}
			else {
			tsduOffset += numBytesToWrite;
			}
			numBytesToWrite = 0;
			}
			}

			os.flush();
			}
			}

			public void send_ex(byte[] tsdu, int offset, int length) throws IOException {
			List<byte[]> tsdus = new ArrayList<>();
			tsdus.add(tsdu);
			List<Integer> offsets = new ArrayList<>();
			offsets.add(offset);
			List<Integer> lengths = new ArrayList<>();
			lengths.add(length);
			send(tsdus, offsets, lengths);
			}

			public int getMessageTimeout() {
			return messageTimeout;
			}

			/**
			* Set the TConnection timeout for waiting for the first byte of a new message. Default is 0 (unlimited)
			*
			* @param messageTimeout
			* in milliseconds
			*/
			public void setMessageTimeout(int messageTimeout) {
			this.messageTimeout = messageTimeout;
			}

			public int getMessageFragmentTimeout() {
			return messageFragmentTimeout;
			}

			/**
			* Set the TConnection timeout for receiving data once the beginning of a message has been received. Default is
			* 60000 (60 seconds)
			*
			* @param messageFragmentTimeout
			* in milliseconds
			*/
			public void setMessageFragmentTimeout(int messageFragmentTimeout) {
			this.messageFragmentTimeout = messageFragmentTimeout;
			}

			/**
			* Listens for a new TPDU and writes the extracted TSDU into the passed buffer.
			*
			* @param tSduBuffer
			* the buffer that is filled with the received TSDU data.
			* @throws EOFException
			* if a Disconnect Request (DR) was received or the socket was simply closed
			* @throws SocketTimeoutException
			* if a messageFragmentTimeout is thrown by the socket while receiving the remainder of a message
			* @throws IOException
			* if an ErrorPDU (ER) was received, any syntax error in the received message header was detected or the
			* tSduBuffer is too small to hold the complete PDU.
			* @throws TimeoutException
			* this exception is thrown if the first byte of new message is not received within the message timeout.
			*/
			public void receive(ByteBuffer tSduBuffer)
			throws EOFException, SocketTimeoutException, IOException, TimeoutException {

			tSduBuffer.mark();

			int packetLength;
			int eot = 0;
			int li = 0;
			int tPduCode;

			socket.setSoTimeout(messageTimeout);
			byte version;
			try {
			version = is.readByte();
			} catch (SocketTimeoutException e) {
			throw (new TimeoutException());
			}
			socket.setSoTimeout(messageFragmentTimeout);

			do {
			// read version
			if (version != 3) {
			throw new IOException("Syntax error at beginning of RFC1006 header: version not equal to 3");
			}

			// read reserved
			if (is.readByte() != 0) {
			throw new IOException("Syntax errorat beginning of RFC1006 header: reserved not equal to 0");
			}

			// read packet length
			packetLength = is.readShort() & 0xffff;
			if (packetLength <= 7) {
			throw new IOException("Syntax error: packet length parameter < 7");
			}

			// read length indicator
			li = is.readByte() & 0xff;

			// read TPDU code
			tPduCode = is.readByte() & 0xff;

			if (tPduCode == 0xf0) {
			// Data Transfer (DT) Code

			if (li != 2) {
			throw new IOException("Syntax error: LI field does not equal 2");
			}

			// read EOT
			eot = is.readByte() & 0xff;
			if (eot != 0 && eot != 0x80) {
			throw new IOException("Syntax error: eot wrong");
			}

			if (packetLength - 7 > tSduBuffer.limit() - tSduBuffer.position()) {
			throw new IOException("tSduBuffer size is too small to hold the complete TSDU");
			}
			is.readFully(tSduBuffer.array(), tSduBuffer.arrayOffset() + tSduBuffer.position(), packetLength - 7);
			tSduBuffer.position(tSduBuffer.position() + packetLength - 7);
			}
			else if (tPduCode == 0x80) {
			// Disconnect Request (DR)

			if (li != 6) {
			throw new IOException("Syntax error: LI field does not equal 6");
			}

			// check if the DST-REF field is set to the reference of the
			// receiving entity -> srcRef
			if (is.readShort() != srcRef) {
			throw new IOException("Syntax error: srcRef wrong");
			}

			// check if the SRC-REF field is that of the entity sending
			// the DR
			if (is.readShort() != dstRef) {
			throw new IOException("Syntax error: dstRef wrong");
			}

			// check the reason field, for class 0 only between 1 and 4
			int reason = is.readByte() & 0xff;
			if (reason > 4) {
			throw new IOException("Syntax error: reason out of bound");
			}

			// Disconnect is valid, throw exception
			throw new EOFException("Disconnect request. Reason:" + reason);

			}
			else if (tPduCode == 0x70) {
			throw new IOException("Got TPDU error (ER) message");
			}
			else {
			throw new IOException("Syntax error: unknown TPDU code");
			}

			if (eot != 0x80) {
			version = is.readByte();
			}

			} while (eot != 0x80);

			tSduBuffer.limit(tSduBuffer.position());
			tSduBuffer.reset();
			}

			/**
			* This function sends a Disconnect Request but does not wait for a Disconnect Confirm.
			*/
			public void disconnect() {

			try {
			// write header for rfc
			// write version
			os.write(0x03);
			// write reserved
			os.write(0x00);

			// write packet length
			os.writeShort(4 + 7); // this does not include the variable part
			// which
			// contains additional user information for
			// disconnect

			// beginning of ISO 8073 header
			// write LI
			os.write(0x06);

			// write DR
			os.write(0x80);

			// write DST-REF
			os.writeShort(dstRef);

			// write SRC-REF
			os.writeShort(srcRef);

			// write reason - 0x00 corresponds to reason not specified. Can
			// write
			// the reasons as case structure, but need input from client
			os.write(0x00);

			os.flush();
			} catch (IOException e) {
			} finally {
			close();
			}
			}

			/**
			* Will close the TCP connection if its still open and free any resources of this connection.
			*/
			public void close() {
			if (!closed) {
			closed = true;
			try {
			// will also close socket
			os.close();
			} catch (Exception e) {
			}
			try {
			is.close();
			} catch (Exception e) {
			}
			if (serverThread != null) {
			serverThread.connectionClosedSignal();
			}
			}
			}
			}
			/*
			* Copyright 2011-17 Fraunhofer ISE, energy & meteo Systems GmbH and other contributors
			*
			* Licensed under the Apache License, Version 2.0 (the "License");
			* you may not use this file except in compliance with the License.
			* You may obtain a copy of the License at
			*
			* http://www.apache.org/licenses/LICENSE-2.0
			*
			* Unless required by applicable law or agreed to in writing, software
			* distributed under the License is distributed on an "AS IS" BASIS,
			* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
			* See the License for the specific language governing permissions and
			* limitations under the License.
			*
			*/
			package org.openmuc.jositransport;

			import java.io.BufferedInputStream;
			import java.io.BufferedOutputStream;
			import java.io.DataInputStream;
			import java.io.DataOutputStream;
			import java.io.EOFException;
			import java.io.IOException;
			import java.net.Socket;
			import java.net.SocketTimeoutException;
			import java.nio.ByteBuffer;
			import java.util.ArrayList;
			import java.util.List;
			import java.util.concurrent.TimeoutException;

			public final class TConnection {

			// private static final Logger logger = LoggerFactory.getLogger(TConnection.class);

			private final Socket socket;
			private final DataOutputStream os;
			private final DataInputStream is;
			private static Integer connectionCounter = 0;

			public byte[] tSelRemote = null;
			public byte[] tSelLocal = null;

			private int srcRef;
			private int dstRef;
			private int maxTPduSizeParam;
			private int maxTPduSize;
			private int messageTimeout;
			private int messageFragmentTimeout;

			private boolean closed = false;

			private final ServerThread serverThread;

			TConnection(Socket socket, int maxTPduSizeParam, int messageTimeout, int messageFragmentTimeout,
			ServerThread serverThread) throws IOException {
			if (maxTPduSizeParam < 7 \|\| maxTPduSizeParam > 16) {
			throw new RuntimeException("maxTPduSizeParam is incorrect");
			}
			this.socket = socket;
			os = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
			is = new DataInputStream(new BufferedInputStream(socket.getInputStream()));

			synchronized (socket) {
			connectionCounter++;
			connectionCounter %= 65520;
			if (connectionCounter == 0) {
			connectionCounter = 1; // some servers do not like srcRef 0
			}
			srcRef = connectionCounter;
			}

			this.messageTimeout = messageTimeout;
			this.messageFragmentTimeout = messageFragmentTimeout;
			this.maxTPduSizeParam = maxTPduSizeParam;
			maxTPduSize = ClientTSap.getMaxTPDUSize(maxTPduSizeParam);

			this.serverThread = serverThread;
			}

			/**
			* This function is called once a client has connected to the server. It listens for a Connection Request (CR). If
			* this is successful it replies afterwards with a Connection Confirm (CC). According to the norm a syntax error in
			* the CR should be followed by an ER. This implementation does not send an ER because it seems unnecessary.
			*
			* @throws IOException
			*/
			void listenForCR() throws IOException {

			socket.setSoTimeout(messageFragmentTimeout);

			byte myByte;
			int lengthIndicator;
			int parameterLength;

			//is.available();

			// start reading rfc 1006 header
			if (is.read() != 0x03) {
			throw new IOException();
			}
			if (is.read() != 0) {
			throw new IOException();
			}
			// read Packet length, but is not needed
			is.readShort();
			// reading rfc 1006 header finished

			lengthIndicator = is.read() & 0xff;
			// 0xe0 is the CR-Code
			if ((is.read() & 0xff) != 0xe0) {
			throw new IOException();
			}
			// DST-REF needs to be 0 in a CR packet
			if (is.readShort() != 0) {
			throw new IOException();
			}
			// read the srcRef which is the dstRef for this end-point
			dstRef = is.readShort() & 0xffff;
			// read class
			if ((is.read() & 0xff) != 0) {
			throw new IOException();
			}
			int variableBytesRead = 0;
			while (lengthIndicator > (6 + variableBytesRead)) {
			// read parameter code
			myByte = is.readByte();
			switch (myByte & 0xff) {
			case 0xc2:
			parameterLength = is.readByte() & 0xff;

			if (tSelLocal == null) {
			tSelLocal = new byte[parameterLength];
			is.readFully(tSelLocal);
			}
			else {
			if (parameterLength != tSelLocal.length) {
			throw new IOException("local T-SElECTOR is wrong.");
			}
			for (int i = 0; i < parameterLength; i++) {
			if ((tSelLocal[i] & 0xff) != is.read()) {
			throw new IOException("local T-SElECTOR is wrong.");
			}
			}
			}
			variableBytesRead += 2 + parameterLength;
			break;
			case 0xc1:
			parameterLength = is.readByte() & 0xff;

			if (tSelRemote == null) {
			tSelRemote = new byte[parameterLength];
			is.readFully(tSelRemote);
			}
			else {
			if (parameterLength != tSelRemote.length) {
			throw new IOException("remote T-SElECTOR is wrong.");
			}
			for (int i = 0; i < parameterLength; i++) {
			if ((tSelRemote[i] & 0xff) != is.read()) {
			throw new IOException("remote T-SElECTOR is wrong.");
			}
			}
			}
			variableBytesRead += 2 + parameterLength;
			break;

			case 0xc0:
			if ((is.readByte() & 0xff) != 1) {
			throw new IOException();
			}
			myByte = is.readByte();
			int newMaxTPDUSizeParam = (myByte & 0xff);
			if (newMaxTPDUSizeParam < 7 \|\| newMaxTPDUSizeParam > 16) {
			throw new IOException("maxTPDUSizeParam is out of bound");
			}
			else {
			if (newMaxTPDUSizeParam < maxTPduSizeParam) {
			maxTPduSizeParam = newMaxTPDUSizeParam;
			maxTPduSize = ClientTSap.getMaxTPDUSize(maxTPduSizeParam);
			}
			}
			variableBytesRead += 3;
			break;
			default:
			throw new IOException();
			}

			}

			// write RFC 1006 Header
			os.write(0x03);
			os.write(0x00);
			// write complete packet length

			int variableLength = 3;

			if (tSelLocal != null) {
			variableLength += 2 + tSelLocal.length;
			}
			if (tSelRemote != null) {
			variableLength += 2 + tSelRemote.length;
			}
			os.writeShort(4 + 7 + variableLength);

			// write connection request (CR) TPDU (§13.3)

			// write length indicator
			os.write(6 + variableLength);

			// write fixed part
			// write CC CDT
			os.write(0xd0);
			// write DST-REF
			os.writeShort(dstRef);
			// write SRC-REF
			os.writeShort(srcRef);
			// write class
			os.write(0);

			// write variable part
			if (tSelLocal != null) {
			os.write(0xc2);
			os.write(tSelLocal.length);
			os.write(tSelLocal);
			}

			if (tSelRemote != null) {
			os.write(0xc1);
			os.write(tSelRemote.length);
			os.write(tSelRemote);
			}
			// write proposed maximum TPDU Size
			os.write(0xc0);
			os.write(1);
			os.write(maxTPduSizeParam);

			os.flush();

			}

			/**
			* Starts a connection, sends a CR, waits for a CC and throws an IOException if not successful
			*
			* @throws IOException
			*/
			void startConnection() throws IOException {

			ByteBuffer bf = ByteBuffer.allocate(1024);

			// write RFC 1006 Header
			bf.put((byte) 0x03);
			bf.put((byte) 0x00);

			// write complete packet length
			int variableLength = 3;

			if (tSelLocal != null) {
			variableLength += 2 + tSelLocal.length;
			}
			if (tSelRemote != null) {
			variableLength += 2 + tSelRemote.length;
			}
			bf.putShort((short) (4 + 7 + variableLength));
			// writing RFC 1006 Header finished

			// write connection request (CR) TPDU (§13.3)

			// write length indicator
			bf.put((byte) (6 + variableLength));

			// write fixed part
			// write CR CDT
			bf.put((byte) 0xe0);
			// write DST-REF
			bf.put((byte) 0);
			bf.put((byte) 0);
			// write SRC-REF
			bf.putShort((short) srcRef);
			// write class
			bf.put((byte) 0);

			// write variable part
			// write proposed maximum TPDU Size
			bf.put((byte) 0xc0);
			bf.put((byte) 1);
			bf.put((byte) maxTPduSizeParam);

			if (tSelRemote != null) {
			bf.put((byte) 0xc2);
			bf.put((byte) tSelRemote.length);
			bf.put(tSelRemote);
			}
			if (tSelLocal != null) {
			bf.put((byte) 0xc1);
			bf.put((byte) tSelLocal.length);
			bf.put(tSelLocal);
			}

			bf.flip();
			byte[] outbyte = new byte[bf.limit()];
			bf.get(outbyte);
			os.write(outbyte);

			/*
			// write RFC 1006 Header
			os.write(0x03);
			os.write(0x00);

			// write complete packet length
			int variableLength = 3;

			if (tSelLocal != null) {
			variableLength += 2 + tSelLocal.length;
			}
			if (tSelRemote != null) {
			variableLength += 2 + tSelRemote.length;
			}
			os.writeShort(4 + 7 + variableLength);
			// writing RFC 1006 Header finished

			// write connection request (CR) TPDU (§13.3)

			// write length indicator
			os.write(6 + variableLength);

			// write fixed part
			// write CR CDT
			os.write(0xe0);
			// write DST-REF
			os.write(0);
			os.write(0);
			// write SRC-REF
			os.writeShort(srcRef);
			// write class
			os.write(0);

			// write variable part
			// write proposed maximum TPDU Size
			os.write(0xc0);
			os.write(1);
			os.write(maxTPduSizeParam);

			if (tSelRemote != null) {
			os.write(0xc2);
			os.write(tSelRemote.length);
			os.write(tSelRemote);
			}
			if (tSelLocal != null) {
			os.write(0xc1);
			os.write(tSelLocal.length);
			os.write(tSelLocal);
			}
			*/
			os.flush();

			socket.setSoTimeout(messageTimeout);

			byte myByte;
			int lengthIndicator;
			int parameterLength;
			//is.readFully(outbyte);
			//System.out.println("is.availabless() is : " + is.available());
			/*
			byte res_b = is.readByte();
			ByteBuffer is_bf = ByteBuffer.allocate(is.available()+1);
			is_bf.put(res_b);
			is.readFully(is_bf.array(), 1, is.available());
			*/
			if (is.readByte() != 0x03) {
			throw new IOException();
			}
			if (is.readByte() != 0) {
			throw new IOException();
			}
			//System.out.println("line 376 is.availabless() is : " + is.available());
			// read packet length, but is not needed
			is.readShort();
			lengthIndicator = is.readByte() & 0xff;
			if ((is.readByte() & 0xff) != 0xd0) {
			throw new IOException();
			}
			// read the dstRef which is the srcRef for this end-point
			is.readShort();
			// read the srcRef which is the dstRef for this end-point
			dstRef = is.readShort() & 0xffff;
			// read class
			if (is.readByte() != 0) {
			throw new IOException();
			}

			int variableBytesRead = 0;
			while (lengthIndicator > (6 + variableBytesRead)) {
			// read parameter code
			myByte = is.readByte();
			switch (myByte & 0xff) {

			case 0xc1:
			parameterLength = is.readByte() & 0xff;

			if (tSelLocal == null) {
			tSelLocal = new byte[parameterLength];
			is.readFully(tSelLocal);
			}
			else {
			for (int i = 0; i < parameterLength; i++) {
			//System.out.println("line 407 is.availabless() is : " + is.available());
			is.read();
			}
			}
			variableBytesRead += 2 + parameterLength;
			break;
			case 0xc2:
			parameterLength = is.readByte() & 0xff;

			if (tSelRemote == null) {
			tSelRemote = new byte[parameterLength];
			is.readFully(tSelRemote);
			}
			else {
			for (int i = 0; i < parameterLength; i++) {
			//System.out.println("line 422 is.availabless() is : " + is.available());
			is.read();
			}
			}
			variableBytesRead += 2 + parameterLength;
			break;

			case 0xc0:
			if (is.readByte() != 1) {
			throw new IOException("maxTPduSizeParam size is not equal to 1");
			}
			myByte = is.readByte();
			if ((myByte & 0xff) < 7 \|\| (myByte & 0xff) > maxTPduSizeParam) {
			throw new IOException("maxTPduSizeParam out of bound");
			}
			else {
			if ((myByte & 0xff) < maxTPduSizeParam) {
			maxTPduSizeParam = (myByte & 0xff);
			}
			}
			variableBytesRead += 4;
			break;
			default:
			throw new IOException();
			}

			}

			}

			public void send(List<byte[]> tsdus, List<Integer> offsets, List<Integer> lengths) throws IOException {

			int bytesLeft = 0;
			// for (byte[] tsdu : tsdus) {
			// bytesLeft += tsdu.length;
			// }
			for (int length : lengths) {
			bytesLeft += length;
			}
			int tsduOffset = 0;
			int byteArrayListIndex = 0;
			int numBytesToWrite;
			boolean lastPacket = false;
			int maxTSDUSize = maxTPduSize - 3;
			while (bytesLeft > 0) {

			if (bytesLeft > maxTSDUSize) {
			numBytesToWrite = maxTSDUSize;
			}
			else {
			numBytesToWrite = bytesLeft;
			lastPacket = true;
			}

			// --write RFC 1006 Header--
			// write Version
			os.write(0x03);
			// write reserved bits
			os.write(0);
			// write packet Length
			os.writeShort(numBytesToWrite + 7);

			// --write 8073 Header--
			// write Length Indicator of header
			os.write(0x02);
			// write TPDU Code for DT Data
			os.write(0xf0);
			// write TPDU-NR and EOT, TPDU-NR is always 0 for class 0
			if (lastPacket) {
			os.write(0x80);
			}
			else {
			os.write(0x00);
			}

			bytesLeft -= numBytesToWrite;
			while (numBytesToWrite > 0) {
			byte[] tsdu = tsdus.get(byteArrayListIndex);
			int length = lengths.get(byteArrayListIndex);
			int offset = offsets.get(byteArrayListIndex);

			int tsduWriteLength = length - tsduOffset;

			//System.out.println("send tsduWriteLength " + tsduWriteLength + " numBytesToWrite " + numBytesToWrite);

			if (numBytesToWrite > tsduWriteLength) {
			os.write(tsdu, offset + tsduOffset, tsduWriteLength);
			numBytesToWrite -= tsduWriteLength;
			tsduOffset = 0;
			byteArrayListIndex++;
			}
			else {
			os.write(tsdu, offset + tsduOffset, numBytesToWrite);
			if (numBytesToWrite == tsduWriteLength) {
			tsduOffset = 0;
			byteArrayListIndex++;
			}
			else {
			tsduOffset += numBytesToWrite;
			}
			numBytesToWrite = 0;
			}
			}

			os.flush();
			}
			}

			public void send_ex(byte[] tsdu, int offset, int length) throws IOException {
			List<byte[]> tsdus = new ArrayList<>();
			tsdus.add(tsdu);
			List<Integer> offsets = new ArrayList<>();
			offsets.add(offset);
			List<Integer> lengths = new ArrayList<>();
			lengths.add(length);
			send(tsdus, offsets, lengths);
			}

			public int getMessageTimeout() {
			return messageTimeout;
			}

			/**
			* Set the TConnection timeout for waiting for the first byte of a new message. Default is 0 (unlimited)
			*
			* @param messageTimeout
			* in milliseconds
			*/
			public void setMessageTimeout(int messageTimeout) {
			this.messageTimeout = messageTimeout;
			}

			public int getMessageFragmentTimeout() {
			return messageFragmentTimeout;
			}

			/**
			* Set the TConnection timeout for receiving data once the beginning of a message has been received. Default is
			* 60000 (60 seconds)
			*
			* @param messageFragmentTimeout
			* in milliseconds
			*/
			public void setMessageFragmentTimeout(int messageFragmentTimeout) {
			this.messageFragmentTimeout = messageFragmentTimeout;
			}

			/**
			* Listens for a new TPDU and writes the extracted TSDU into the passed buffer.
			*
			* @param tSduBuffer
			* the buffer that is filled with the received TSDU data.
			* @throws EOFException
			* if a Disconnect Request (DR) was received or the socket was simply closed
			* @throws SocketTimeoutException
			* if a messageFragmentTimeout is thrown by the socket while receiving the remainder of a message
			* @throws IOException
			* if an ErrorPDU (ER) was received, any syntax error in the received message header was detected or the
			* tSduBuffer is too small to hold the complete PDU.
			* @throws TimeoutException
			* this exception is thrown if the first byte of new message is not received within the message timeout.
			*/
			public void receive(ByteBuffer tSduBuffer)
			throws EOFException, SocketTimeoutException, IOException, TimeoutException {

			tSduBuffer.mark();

			int packetLength;
			int eot = 0;
			int li = 0;
			int tPduCode;

			socket.setSoTimeout(messageTimeout);
			byte version;
			try {
			version = is.readByte();
			} catch (SocketTimeoutException e) {
			throw (new TimeoutException());
			}
			socket.setSoTimeout(messageFragmentTimeout);

			do {
			// read version
			if (version != 3) {
			throw new IOException("Syntax error at beginning of RFC1006 header: version not equal to 3");
			}

			// read reserved
			if (is.readByte() != 0) {
			throw new IOException("Syntax errorat beginning of RFC1006 header: reserved not equal to 0");
			}

			// read packet length
			packetLength = is.readShort() & 0xffff;
			if (packetLength <= 7) {
			throw new IOException("Syntax error: packet length parameter < 7");
			}

			// read length indicator
			li = is.readByte() & 0xff;

			// read TPDU code
			tPduCode = is.readByte() & 0xff;

			if (tPduCode == 0xf0) {
			// Data Transfer (DT) Code

			if (li != 2) {
			throw new IOException("Syntax error: LI field does not equal 2");
			}

			// read EOT
			eot = is.readByte() & 0xff;
			if (eot != 0 && eot != 0x80) {
			throw new IOException("Syntax error: eot wrong");
			}

			if (packetLength - 7 > tSduBuffer.limit() - tSduBuffer.position()) {
			throw new IOException("tSduBuffer size is too small to hold the complete TSDU");
			}
			is.readFully(tSduBuffer.array(), tSduBuffer.arrayOffset() + tSduBuffer.position(), packetLength - 7);
			tSduBuffer.position(tSduBuffer.position() + packetLength - 7);
			}
			else if (tPduCode == 0x80) {
			// Disconnect Request (DR)

			if (li != 6) {
			throw new IOException("Syntax error: LI field does not equal 6");
			}

			// check if the DST-REF field is set to the reference of the
			// receiving entity -> srcRef
			if (is.readShort() != srcRef) {
			throw new IOException("Syntax error: srcRef wrong");
			}

			// check if the SRC-REF field is that of the entity sending
			// the DR
			if (is.readShort() != dstRef) {
			throw new IOException("Syntax error: dstRef wrong");
			}

			// check the reason field, for class 0 only between 1 and 4
			int reason = is.readByte() & 0xff;
			if (reason > 4) {
			throw new IOException("Syntax error: reason out of bound");
			}

			// Disconnect is valid, throw exception
			throw new EOFException("Disconnect request. Reason:" + reason);

			}
			else if (tPduCode == 0x70) {
			throw new IOException("Got TPDU error (ER) message");
			}
			else {
			throw new IOException("Syntax error: unknown TPDU code");
			}

			if (eot != 0x80) {
			version = is.readByte();
			}

			} while (eot != 0x80);

			tSduBuffer.limit(tSduBuffer.position());
			tSduBuffer.reset();
			}

			/**
			* This function sends a Disconnect Request but does not wait for a Disconnect Confirm.
			*/
			public void disconnect() {

			try {
			// write header for rfc
			// write version
			os.write(0x03);
			// write reserved
			os.write(0x00);

			// write packet length
			os.writeShort(4 + 7); // this does not include the variable part
			// which
			// contains additional user information for
			// disconnect

			// beginning of ISO 8073 header
			// write LI
			os.write(0x06);

			// write DR
			os.write(0x80);

			// write DST-REF
			os.writeShort(dstRef);

			// write SRC-REF
			os.writeShort(srcRef);

			// write reason - 0x00 corresponds to reason not specified. Can
			// write
			// the reasons as case structure, but need input from client
			os.write(0x00);

			os.flush();
			} catch (IOException e) {
			} finally {
			close();
			}
			}

			/**
			* Will close the TCP connection if its still open and free any resources of this connection.
			*/
			public void close() {
			if (!closed) {
			closed = true;
			try {
			// will also close socket
			os.close();
			} catch (Exception e) {
			}
			try {
			is.close();
			} catch (Exception e) {
			}
			if (serverThread != null) {
			serverThread.connectionClosedSignal();
			}
			}
			}
			}