public static byte[] reverseAuthenticatedEncryption(CosemParameters parameters, CosemConnection connection, byte[] data)
{
switch (data[0] & 0xff)
{
case SC_AUTHENTICATION:
byte[] aux = helper.extensions.copyOfRange(data, 1, 5);
connection.serverInvocationCounter = BitConverter.ToInt32(new byte[] { (aux[3]), (aux[2]), (aux[1]), (aux[0]) }, 0);
return(aesGcmReverse(new byte[0], helper.extensions.copyOfRange(data, 5, data.Length), parameters, connection));
case SC_AUTHENTICATION_ENCRYPTION:
byte[] authData = new byte[parameters.ak.Length + 1];
authData[0] = SC_AUTHENTICATION_ENCRYPTION;
Array.Copy(parameters.ak, 0, authData, 1, parameters.ak.Length);
aux = helper.extensions.copyOfRange(data, 1, 5);
connection.serverInvocationCounter = BitConverter.ToInt32(new byte[] { (aux[3]), (aux[2]), (aux[1]), (aux[0]) }, 0);
return(aesGcmReverse(helper.extensions.copyOfRange(data, 5, data.Length), authData, parameters, connection));
case SC_ENCRYPTION:
aux = helper.extensions.copyOfRange(data, 1, 5);
connection.serverInvocationCounter = BitConverter.ToInt32(new byte[] { (aux[3]), (aux[2]), (aux[1]), (aux[0]) }, 0);
return(aesGcmReverse(helper.extensions.copyOfRange(data, 5, data.Length), new byte[0], parameters, connection));
default:
return(data);
}
}
private static byte[] generateInitiateRequest(CosemParameters parameters)
{
System.IO.MemoryStream stream = new System.IO.MemoryStream();
stream.WriteByte(Constants.xDlmsApdu.NoCiphering.INITIATE_REQUEST);
stream.WriteByte(0); //Dedicated key
stream.WriteByte(0); //Response-allowed
stream.WriteByte(0); //Proposed quality of service
stream.WriteByte(Constants.DLMS_VERSION); //Dlms version
stream.WriteByte(Constants.ConformanceBlock.TAG); //Conformance block tag
byte[] conformance = generateConformanceBlock(parameters);
stream.WriteByte((byte)(conformance.Length));
stream.Write(conformance, 0, conformance.Length); //Conformance block
//stream.WriteByte(ByteBuffer.allocate(2).putShort(parameters.maxPduSize).array());
stream.WriteByte((byte)(parameters.maxPduSize >> 8)); //Max pdu size
stream.WriteByte((byte)(parameters.maxPduSize));
System.IO.MemoryStream stream2 = new System.IO.MemoryStream();
if (parameters.securityType != SecurityType.NONE)
{
stream2.WriteByte(Constants.xDlmsApdu.GlobalCiphering.INITIATE_REQUEST);
byte[] data = Security.authenticatedEncryption(parameters, stream.ToArray());
stream2.WriteByte((byte)(data.Length));
stream2.Write(data, 0, data.Length);
}
else
{
//stream2.WriteByte(stream.ToArray());
byte[] aux = stream.ToArray();
stream2.Write(aux, 0, aux.Length);
}
return(stream2.ToArray());
}
public static byte[] authenticatedEncryption(CosemParameters parameters, byte[] data)
{
if (parameters.securityType == SecurityType.NONE)
{
return(data);
}
int ivCounter = parameters.getInvocationCounter();
int sc = 0;
switch (parameters.securityType)
{
case SecurityType.AUTHENTICATION:
sc = SC_AUTHENTICATION;
byte[] authData = new byte[parameters.ak.Length + data.Length + 1];
authData[0] = SC_AUTHENTICATION;
Array.Copy(parameters.ak, 0, authData, 1, parameters.ak.Length);
Array.Copy(data, 0, authData, parameters.ak.Length + 1, data.Length);
byte[] mac = aesGcm(new byte[0], authData, parameters, ivCounter);
byte[] data_ = new byte[data.Length + mac.Length];
Array.Copy(data, 0, data_, 0, data.Length);
Array.Copy(mac, 0, data_, data.Length, mac.Length);
data = data_;
break;
case SecurityType.AUTHENTICATION_ENCRYPTION:
sc = SC_AUTHENTICATION_ENCRYPTION;
authData = new byte[parameters.ak.Length + 1];
authData[0] = SC_AUTHENTICATION_ENCRYPTION;
Array.Copy(parameters.ak, 0, authData, 1, parameters.ak.Length);
data = aesGcm(data, authData, parameters, ivCounter);
break;
case SecurityType.ENCRYPTION:
sc = SC_ENCRYPTION;
data = aesGcm(data, new byte[0], parameters, ivCounter);
break;
default:
throw new System.InvalidOperationException();
}
try
{
System.IO.MemoryStream stream = new System.IO.MemoryStream();
stream.WriteByte((byte)sc);
stream.WriteByte((byte)(ivCounter >> 24));
stream.WriteByte((byte)(ivCounter >> 16));
stream.WriteByte((byte)(ivCounter >> 8));
stream.WriteByte((byte)(ivCounter));
stream.Write(data, 0, data.Length);
return(stream.ToArray());
}
catch (IOException)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.INTERNAL_ERROR);
}
}
internal static byte[] generateChallanger(CosemParameters parameters)
{
byte[] random = new byte[parameters.challengerSize];
lock (randomLocker)
{
sr.NextBytes(random);
}
return(random);
}
internal static bool verifyChallenger(CosemParameters parameters, CosemConnection connection, byte[] data)
{
if (data == null || data.Length == 0)
{
return(false);
}
try
{
byte[] calculated = new byte[0];
switch (parameters.authenticationType.innerEnumValue)
{
case AuthenticationType.InnerEnum.PUBLIC:
case AuthenticationType.InnerEnum.LLS:
throw new System.InvalidOperationException();
case AuthenticationType.InnerEnum.HLS:
calculated = aes128(connection.challengeServerToClient, parameters.llsHlsSecret);
break;
case AuthenticationType.InnerEnum.HLS_MD5:
calculated = md5(connection.challengeClientToServer, parameters.llsHlsSecret);
break;
case AuthenticationType.InnerEnum.HLS_SHA1:
calculated = sha1(connection.challengeClientToServer, parameters.llsHlsSecret);
break;
case AuthenticationType.InnerEnum.HLS_GMAC:
if (data[0] != SC_AUTHENTICATION)
{
return(false);
}
System.IO.MemoryStream stream = new System.IO.MemoryStream();
stream.WriteByte(SC_AUTHENTICATION);
stream.Write(parameters.ak, 0, parameters.ak.Length);
stream.Write(connection.challengeClientToServer, 0, connection.challengeClientToServer.Length);
//connection.serverInvocationCounter = BitConverter.ToInt32(helper.extensions.copyOfRange(data, 1, 5), 0);
var aux = helper.extensions.copyOfRange(data, 1, 5);
connection.serverInvocationCounter = BitConverter.ToInt32(new byte[] { (aux[3]), (aux[2]), (aux[1]), (aux[0]) }, 0);
data = helper.extensions.copyOfRange(data, 5, data.Length);
CosemParameters cosemParams = new CosemParameters();
cosemParams.setSystemTitle(connection.serverSysTitle);
cosemParams.setEk(parameters.ek);
calculated = Security.aesGcm(new byte[0], stream.ToArray(), cosemParams, connection.serverInvocationCounter);
break;
default:
throw new System.ArgumentException();
}
return(Enumerable.SequenceEqual(data, calculated));
}
catch (IOException)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.INTERNAL_ERROR);
}
}
public static byte[] aesGcmReverse(byte[] encrypted, byte[] authData, CosemParameters parameters, CosemConnection connection)
{
try
{
byte[] iv = getIv(connection.serverSysTitle, connection.serverInvocationCounter);
lock (cipherLocker)
{
using (var cipherStream = new MemoryStream(encrypted))
using (var cipherReader = new BinaryReader(cipherStream))
{
var cipher = new GcmBlockCipher(new AesEngine());
cipher.Init(false, new AeadParameters(new KeyParameter(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }), MacBitSize, iv));
var cipherText = cipherReader.ReadBytes(encrypted.Length);
var plainText = new byte[cipher.GetOutputSize(cipherText.Length)];
var len = cipher.ProcessBytes(cipherText, 0, cipherText.Length, plainText, 0);
cipher.ProcessAadBytes(authData, 0, authData.Length);
cipher.DoFinal(plainText, len);
return(plainText);
}
}
}
catch (InvalidKeyException e)
{
Console.WriteLine(e.ToString());
Console.Write(e.StackTrace);
}
//catch (InvalidAlgorithmParameterException e)
catch (InvalidParameterException e)
{
Console.WriteLine(e.ToString());
Console.Write(e.StackTrace);
}
//catch (IllegalBlockSizeException e)
catch (CryptographicException e)
{
Console.WriteLine(e.ToString());
Console.Write(e.StackTrace);
}
//catch (AEADBadTagException)
//{
// throw new DlmsException(DlmsException.DlmsExceptionReason.SECURITY_FAIL);
//}
//catch (BadPaddingException e)
//{
// Console.WriteLine(e.ToString());
// Console.Write(e.StackTrace);
//}
throw new DlmsException(DlmsException.DlmsExceptionReason.INTERNAL_ERROR);
}
internal static byte[] processChallanger(CosemParameters parameters, CosemConnection connection)
{
try
{
switch (parameters.authenticationType.innerEnumValue)
{
case AuthenticationType.InnerEnum.PUBLIC:
case AuthenticationType.InnerEnum.LLS:
throw new System.InvalidOperationException();
case AuthenticationType.InnerEnum.HLS:
return(aes128(connection.challengeServerToClient, parameters.llsHlsSecret));
case AuthenticationType.InnerEnum.HLS_MD5:
return(md5(connection.challengeServerToClient, parameters.llsHlsSecret));
case AuthenticationType.InnerEnum.HLS_SHA1:
return(sha1(connection.challengeServerToClient, parameters.llsHlsSecret));
case AuthenticationType.InnerEnum.HLS_GMAC:
int ivCounter = parameters.getInvocationCounter();
System.IO.MemoryStream data = new System.IO.MemoryStream();
data.WriteByte(SC_AUTHENTICATION);
data.Write(parameters.ak, 0, parameters.ak.Length);
data.Write(connection.challengeServerToClient, 0, connection.challengeServerToClient.Length);
System.IO.MemoryStream stream = new System.IO.MemoryStream();
stream.WriteByte(SC_AUTHENTICATION);
stream.WriteByte((byte)(ivCounter >> 24));
stream.WriteByte((byte)(ivCounter >> 16));
stream.WriteByte((byte)(ivCounter >> 8));
stream.WriteByte((byte)(ivCounter));
byte[] aux = Security.aesGcm(new byte[0], data.ToArray(), parameters, ivCounter);
stream.Write(aux, 0, aux.Length);
return(stream.ToArray());
default:
throw new System.ArgumentException();
}
}
catch (IOException)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.INTERNAL_ERROR);
}
}
public static byte[] aesGcm(byte[] data, byte[] authData, CosemParameters parameters, int ivCounter)
{
try
{
byte[] iv = getIv(parameters.systemTitle, ivCounter);
lock (cipherLocker)
{
var cipher = new GcmBlockCipher(new AesEngine());
cipher.Init(true, new AeadParameters(new KeyParameter(parameters.ek), MacBitSize, iv));
var cipherText = new byte[cipher.GetOutputSize(data.Length)];
var len = cipher.ProcessBytes(data, 0, data.Length, cipherText, 0);
cipher.ProcessAadBytes(authData, 0, authData.Length);
cipher.DoFinal(cipherText, len);
return(cipherText);
}
}
catch (InvalidKeyException e)
{
Console.WriteLine(e.ToString());
Console.Write(e.StackTrace);
}
catch (InvalidParameterException e)
{
Console.WriteLine(e.ToString());
Console.Write(e.StackTrace);
}
catch (CryptographicException e)
{
Console.WriteLine(e.ToString());
Console.Write(e.StackTrace);
}
//catch (AEADBadTagException)
//{
// throw new DlmsException(DlmsException.DlmsExceptionReason.SECURITY_FAIL);
//}
//catch (BadPaddingException e)
//{
// Console.WriteLine(e.ToString());
// Console.Write(e.StackTrace);
//}
throw new DlmsException(DlmsException.DlmsExceptionReason.INTERNAL_ERROR);
}
private static byte[] generateConformanceBlock(CosemParameters parameters)
{
int conformanceBlock = 0;
if (parameters.referenceType == ReferenceType.SHORT_NAME)
{
conformanceBlock |= Constants.ConformanceBlock.READ;
conformanceBlock |= Constants.ConformanceBlock.WRITE;
}
if (parameters.referenceType == ReferenceType.LOGICAL_NAME)
{
conformanceBlock |= Constants.ConformanceBlock.GET;
conformanceBlock |= Constants.ConformanceBlock.SET;
}
conformanceBlock |= Constants.ConformanceBlock.ACTION;
conformanceBlock |= Constants.ConformanceBlock.BLOCK_TRANSFER_WITH_ACTION;
conformanceBlock |= Constants.ConformanceBlock.BLOCK_TRANSFER_WITH_GET_OR_READ;
conformanceBlock |= Constants.ConformanceBlock.BLOCK_TRANSFER_WITH_SET_OR_WRITE;
conformanceBlock |= Constants.ConformanceBlock.SELECTIVE_ACCESS;
//return ByteBuffer.allocate(4).putInt(conformanceBlock).array();
return(new byte[] { (byte)(conformanceBlock >> 24), (byte)(conformanceBlock >> 16), (byte)(conformanceBlock >> 8), (byte)(conformanceBlock) });
}
internal static byte[] request(CosemParameters parameters, CosemConnection connection)
{
const int BASE = Constants.Ber.CLASS_CONTEXT | Constants.Ber.CONSTRUCTED;
byte[] applicationContextName = generateApplicationContextName(parameters.referenceType, parameters.securityType);
connection.proposedContextName = applicationContextName;
System.IO.MemoryStream data = new System.IO.MemoryStream();
//TODO
if (parameters.authenticationType == AuthenticationType.PUBLIC)
{
//data.WriteByte(new byte[] {(byte)0x80, 0x02, 0x07, (byte)0x80});
byte[] aux = new byte[] { (byte)0x80, 0x02, 0x07, (byte)0x80 };
data.Write(aux, 0, aux.Length);
}
data.WriteByte(BASE | Constants.AarqApdu.APPLICATION_CONTEXT_NAME);
data.WriteByte((byte)(applicationContextName.Length + 2));
data.WriteByte(Constants.Ber.OBJECT_IDENTIFIER);
data.WriteByte((byte)(applicationContextName.Length));
data.Write(applicationContextName, 0, applicationContextName.Length); //big or little endian?
if (parameters.securityType != SecurityType.NONE || parameters.authenticationType == AuthenticationType.HLS_GMAC)
{
data.WriteByte(BASE | Constants.Ber.OBJECT_IDENTIFIER);
data.WriteByte((byte)(parameters.systemTitle.Length + 2));
data.WriteByte(Constants.Ber.OCTET_STRING);
data.WriteByte((byte)(parameters.systemTitle.Length));
//data.WriteByte((byte)(parameters.systemTitle));
byte[] aux = parameters.systemTitle;
data.Write(aux, 0, aux.Length);
}
if (parameters.authenticationType != AuthenticationType.PUBLIC)
{
data.WriteByte(Constants.Ber.CLASS_CONTEXT | Constants.AarqApdu.SENDER_ACSE_REQUIREMENTS);
data.WriteByte(2);
data.WriteByte(Constants.Ber.BIT_STRING | Constants.Ber.OCTET_STRING);
data.WriteByte(0x80);
data.WriteByte(Constants.Ber.CLASS_CONTEXT | Constants.AarqApdu.MECHANISM_NAME);
data.WriteByte(7);
//data.WriteByte(new byte[]{0x60, (byte)0x85, 0x74, 0x05, 0x08, 0x02, (byte)parameters.authenticationType.value});
byte[] aux = new byte[] { 0x60, (byte)0x85, 0x74, 0x05, 0x08, 0x02, (byte)parameters.authenticationType.value };
data.Write(aux, 0, aux.Length);
data.WriteByte(BASE | Constants.AarqApdu.CALLING_AUTHENTICATION_VALUE);
if (parameters.authenticationType == AuthenticationType.LLS)
{
data.WriteByte((byte)(parameters.llsHlsSecret.Length + 2));
data.WriteByte(Constants.Ber.CLASS_CONTEXT);
data.WriteByte((byte)(parameters.llsHlsSecret.Length));
//data.WriteByte(parameters.llsHlsSecret);
byte[] aux2 = parameters.llsHlsSecret;
data.Write(aux2, 0, aux2.Length);
}
else if (parameters.authenticationType != AuthenticationType.PUBLIC)
{
connection.challengeClientToServer = Security.generateChallanger(parameters);
data.WriteByte((byte)(connection.challengeClientToServer.Length + 2));
data.WriteByte(Constants.Ber.CLASS_CONTEXT);
data.WriteByte((byte)(connection.challengeClientToServer.Length));
//data.WriteByte(connection.challengeClientToServer);
byte[] aux2 = connection.challengeClientToServer;
data.Write(aux2, 0, aux2.Length);
}
}
data.WriteByte(Constants.Ber.CONTEXT_CONSTRUCTED | Constants.AarqApdu.USER_INFORMATION);
byte[] initiateRequest = generateInitiateRequest(parameters);
data.WriteByte((byte)(initiateRequest.Length + 2));
data.WriteByte(Constants.Ber.OCTET_STRING);
data.WriteByte((byte)(initiateRequest.Length));
data.Write(initiateRequest, 0, initiateRequest.Length);
System.IO.MemoryStream stream = new System.IO.MemoryStream();
stream.WriteByte(Constants.Ber.CLASS_APPLICATION | Constants.Ber.CONSTRUCTED);
stream.WriteByte((byte)(data.Length));
stream.Write(data.ToArray(), 0, data.ToArray().Length);
return(stream.ToArray());
}
/// <summary>
/// Creates a Cosem object </summary>
/// <param name="params"> CosemParameters for this Cosem object </param>
public Cosem(CosemParameters parameters)
{
this.parameters = parameters;
this.connection = new CosemConnection();
}
internal static void parseResponse(CosemParameters parameters, CosemConnection connection, byte[] data)
{
if (data == null || data.Length < 4)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
if ((data[0] & 0xFF) != Constants.AareApdu.APPLICATION_1)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
if ((data[1] & 0xFF) != data.Length - 2)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
if ((data[2] & 0xFF) != (Constants.Ber.CONTEXT_CONSTRUCTED | Constants.AareApdu.APPLICATION_CONTEXT_NAME))
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
int offset = (data[3] & 0xFF) + 4;
parseContextName(helper.extensions.copyOfRange(data, 4, offset), connection.proposedContextName);
if ((data[offset++] & 0xFF) != (Constants.Ber.CONTEXT_CONSTRUCTED | Constants.AareApdu.RESULT))
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
int resultLen = data[offset++] & 0xFF;
byte[] result = helper.extensions.copyOfRange(data, offset, offset + resultLen);
offset += resultLen;
if ((data[offset++] & 0xFF) != (Constants.Ber.CONTEXT_CONSTRUCTED | Constants.AareApdu.RESULT_SOURCE_DIAGNOSTIC))
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
resultLen = data[offset++] & 0xFF;
byte[] diagnostic = helper.extensions.copyOfRange(data, offset, offset + resultLen);
offset += resultLen;
parseResultAndDiagnostic(result, diagnostic);
//Parse optional tags
while (offset < data.Length)
{
int tag = (data[offset++] & 0xFF);
int len = (data[offset++] & 0xFF);
if (data.Length < (offset + len))
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
byte[] value = helper.extensions.copyOfRange(data, offset, offset + len);
offset += len;
if (tag == (Constants.Ber.CONTEXT_CONSTRUCTED | Constants.AareApdu.RESPONDING_AP_TITLE))
{
if (value[0] != Constants.Ber.OCTET_STRING || value[1] != value.Length - 2)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
connection.serverSysTitle = helper.extensions.copyOfRange(value, 2, value.Length);
StringBuilder sb = new StringBuilder();
foreach (byte b in connection.serverSysTitle)
{
sb.Append(b);
}
Console.WriteLine(sb);
}
else if (tag == (Constants.Ber.CLASS_CONTEXT | Constants.AareApdu.RESPONDER_ACSE_REQUIREMENTS))
{
//System.out.println("Resp ACSE Req: "+printBytes(value));
}
else if (tag == (Constants.Ber.CLASS_CONTEXT | Constants.AareApdu.MECHANISM_NAME))
{
//System.out.println("Mechanism Name: "+printBytes(value));
}
else if (tag == (Constants.Ber.CONTEXT_CONSTRUCTED | Constants.AareApdu.RESPONDING_AUTHENTICATION_VALUE))
{
if ((value[0] & 0xFF) != 0x80 || value[1] != value.Length - 2)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
connection.challengeServerToClient = helper.extensions.copyOfRange(value, 2, value.Length);
}
else if (tag == (Constants.Ber.CONTEXT_CONSTRUCTED | Constants.AareApdu.USER_INFORMATION))
{
parseUserInfo(value, parameters, connection);
}
}
}
private static void parseUserInfo(byte[] data, CosemParameters parameters, CosemConnection connection)
{
if (data == null || data.Length < 16)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
if (data[0] != Constants.Ber.OCTET_STRING)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
if (data[1] < 14 || data[1] != data.Length - 2)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
if (parameters.securityType != SecurityType.NONE)
{
if (data[2] != Constants.xDlmsApdu.GlobalCiphering.INITIATE_RESPONSE)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
if (data[3] != data.Length - 4)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
byte[] encrypted = new byte[data[3] & 0xFF];
Array.Copy(data, 4, encrypted, 0, encrypted.Length);
data = Security.reverseAuthenticatedEncryption(parameters, connection, encrypted);
}
else
{
data = helper.extensions.copyOfRange(data, 2, data.Length);
}
if (data[0] != Constants.xDlmsApdu.NoCiphering.INITIATE_RESPONSE)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
if (data[1] != 0 || data[2] != Constants.DLMS_VERSION)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
if (data[3] != Constants.ConformanceBlock.TAG)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
if (data[4] != 0x1F || data[5] != 0x04 || data[6] != 0x00)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
connection.conformanceBlock = helper.extensions.copyOfRange(data, 7, 10);
//int vaa = ByteBuffer.allocate(2).put(Arrays.copyOfRange(data, 12, data.Length)).getShort(0);
byte[] aux = helper.extensions.copyOfRange(data, 12, data.Length);
int vaa = BitConverter.ToInt16(new byte[] { (aux[1]), (aux[0]) }, 0);
if (parameters.referenceType == ReferenceType.LOGICAL_NAME && vaa != 0x0007)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
if (parameters.referenceType == ReferenceType.SHORT_NAME && vaa != 0xFA00)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.MALFORMED_AARE_FRAME);
}
connection.maxPduSize = ((data[10] & 0xFF) << 8) | (data[11] & 0xFF);
}