// get bytes without lenght indicator and pdu type
public byte[] GetBytes()
{
int len = 5; // dest-ref, src-ref, option
foreach (VarParam v in Varpart)
{
len += 1 + 1 + v.length;
}
byte[] res = new byte[len];
if (BitConverter.IsLittleEndian)
{
Buffer.BlockCopy(BitConverter.GetBytes(ByteConvert.DoReverseEndian(DstRef)), 0, res, 0, 2);
Buffer.BlockCopy(BitConverter.GetBytes(ByteConvert.DoReverseEndian(SrcRef)), 0, res, 2, 2);
}
else
{
Buffer.BlockCopy(BitConverter.GetBytes(DstRef), 0, res, 0, 2);
Buffer.BlockCopy(BitConverter.GetBytes(SrcRef), 0, res, 2, 2);
}
res[4] = (byte)ClassOption;
int pos = 5;
foreach (VarParam v in Varpart)
{
res[pos++] = v.code;
res[pos++] = v.length;
Buffer.BlockCopy(v.value, 0, res, pos, v.length);
pos += v.length;
}
return(res);
}
/// <summary>
/// Extract data from TPKT packet. Length is read from parameter packetLen
/// </summary>
/// <param name="packet"></param>
/// <param name="packetLen"></param>
public TPKT(byte[] packet, int packetLen)
{
if (packetLen < TPKT_HEADER_LENGTH)
{
throw new Exception("TPKT: The packet did not contain the minimum number of bytes for an TPKT header packet.");
}
Version = packet[0];
if (Version != 3)
{
throw new Exception("TPKT: Version in header is not valid (!=3).");
}
if (BitConverter.IsLittleEndian)
{
Length = ByteConvert.DoReverseEndian(BitConverter.ToUInt16(packet, 2));
}
else
{
Length = BitConverter.ToUInt16(packet, 2);
}
if (Length > packetLen)
{
throw new Exception("TPKT: Length in header is greater than packet length.");
}
PayloadLength = Length - TPKT_HEADER_LENGTH;
_Payload = new byte[PayloadLength];
Array.Copy(packet, 4, _Payload, 0, PayloadLength);
}
public override void OnReceiveData(ConnectionState state)
{
client = state;
byte[] buffer = new byte[1460];
int tpktlen = 0;
while (state.AvailableData > 0)
{
int readBytes;
// Read length from TPKT header first
readBytes = client.Read(buffer, 0, 4);
if (readBytes > 0)
{
// TPKT Header
if (buffer[0] == 3 && buffer[1] == 0) // Version = 3 / Reserved = 0
{
if (BitConverter.IsLittleEndian)
{
tpktlen = ByteConvert.DoReverseEndian(BitConverter.ToUInt16(buffer, 2));
}
else
{
tpktlen = BitConverter.ToUInt16(buffer, 2);
}
// try to read the TPDU to offset 4 in buffer, this is the length from TPKT minus length of TPKT header
readBytes = client.Read(buffer, 4, tpktlen - 4);
}
else
{
// Wrong TPKT header
client.EndConnection();
return;
}
}
// If TDPU could be read completely
if (readBytes == (tpktlen - 4))
{
try
{
ISOsrv.Process(this, buffer, readBytes + 4);
if (ISOsrv.Connected == false)
{
client.EndConnection();
}
}
catch (Exception)
{
client.EndConnection();
}
}
else
{
client.EndConnection();
}
}
}
public TPDUConnection(byte[] packet)
{
int pos;
int li = packet[0];
TPDU.TPDU_TYPES type = (TPDU.TPDU_TYPES)(packet[1] >> 4);
if ((type != TPDU.TPDU_TYPES.CR) && (type != TPDU.TPDU_TYPES.CC))
{
throw new ApplicationException("TPDU: This can only handle CC/CR TDPUs");
}
if (BitConverter.IsLittleEndian)
{
DstRef = ByteConvert.DoReverseEndian(BitConverter.ToUInt16(packet, 2));
SrcRef = ByteConvert.DoReverseEndian(BitConverter.ToUInt16(packet, 4));
}
else
{
DstRef = BitConverter.ToUInt16(packet, 2);
SrcRef = BitConverter.ToUInt16(packet, 4);
}
ClassOption = ((packet[6] & 0xf0) >> 4);
if (ClassOption > 4)
{
throw new Exception("TPDU: Class option number not allowed.");
}
pos = 7;
// read variable part
Varpart = new ArrayList();
try
{
while (pos < li)
{
VarParam vp = new VarParam();
vp.code = packet[pos];
pos += 1;
vp.length = packet[pos];
pos += 1;
vp.value = new byte[vp.length];
Array.Copy(packet, pos, vp.value, 0, vp.length);
pos += vp.length;
Varpart.Add(vp);
}
}
catch (Exception)
{
throw new Exception("TPDU: Error parsing variable part of CR/CC PDU.");
}
}
public byte[] GetBytes()
{
byte[] tpkt = new byte[Length];
tpkt[0] = Convert.ToByte(Version);
tpkt[1] = Convert.ToByte(Reserved);
if (BitConverter.IsLittleEndian)
{
Buffer.BlockCopy(BitConverter.GetBytes(ByteConvert.DoReverseEndian(Length)), 0, tpkt, 2, 2);
}
else
{
Buffer.BlockCopy(BitConverter.GetBytes(Length), 0, tpkt, 2, 2);
}
Array.Copy(_Payload, 0, tpkt, TPKT_HEADER_LENGTH, PayloadLength);
return(tpkt);
}
