/// <summary>
/// Reads a TPKT from the socket Async
/// </summary>
/// <param name="stream">The stream to read from</param>
/// <returns>Task TPKT Instace</returns>
public static async Task <TPKT> ReadAsync(Stream stream)
{
var buf = new byte[4];
int len = await stream.ReadAsync(buf, 0, 4);
if (len < 4)
{
throw new TPKTInvalidException("TPKT is incomplete / invalid");
}
var pkt = new TPKT
{
Version = buf[0],
Reserved1 = buf[1],
Length = buf[2] * 256 + buf[3] //BigEndian
};
if (pkt.Length > 0)
{
pkt.Data = new byte[pkt.Length - 4];
len = await stream.ReadAsync(pkt.Data, 0, pkt.Length - 4);
if (len < pkt.Length - 4)
{
throw new TPKTInvalidException("TPKT is incomplete / invalid");
}
}
return(pkt);
}
/// <summary>
/// Reads COTP TPDU (Transport protocol data unit) from the network stream
/// See: https://tools.ietf.org/html/rfc905
/// </summary>
/// <param name="stream">The socket to read from</param>
/// <returns>COTP DPDU instance</returns>
public static TPDU Read(Stream stream)
{
var tpkt = TPKT.Read(stream);
if (tpkt.Length > 0)
{
return(new TPDU(tpkt));
}
return(null);
}
/// <summary>
/// Reads COTP TPDU (Transport protocol data unit) from the network stream
/// See: https://tools.ietf.org/html/rfc905
/// </summary>
/// <param name="stream">The socket to read from</param>
/// <returns>COTP DPDU instance</returns>
public static async Task <TPDU> ReadAsync(Stream stream)
{
var tpkt = await TPKT.ReadAsync(stream);
if (tpkt.Length > 0)
{
return(new TPDU(tpkt));
}
return(null);
}
public TPDU(TPKT tPKT)
{
var br = new BinaryReader(new MemoryStream(tPKT.Data));
HeaderLength = br.ReadByte();
if (HeaderLength >= 2)
{
PDUType = br.ReadByte();
if (PDUType == 0xf0) //DT Data
{
var flags = br.ReadByte();
TPDUNumber = flags & 0x7F;
LastDataUnit = (flags & 0x80) > 0;
Data = br.ReadBytes(tPKT.Length - HeaderLength - 4); //4 = TPKT Size
return;
}
//TODO: Handle other PDUTypes
}
Data = new byte[0];
}