How to tcp/ip header

Question

User-1379762086 posted

Dear all, the below code is how am returning a tcp message to a client machine, but the company demanded i should be adding a tcp/ip header to the message. They said the header should be a  2-byte header prefixed which will indicate the length on the TCP/IP stream. can anybody help me on how i can include the header on the below code

	private static void Send(Socket handler, String data)
	{
		// Convert the string data to byte data using ASCII encoding. 
		byte[] byteData = Encoding.ASCII.GetBytes(data);
		// Begin sending the data to the remote device. 
		handler.BeginSend(byteData, 0, byteData.Length, 0, new AsyncCallback(SendCallback), handler);
	}

Answer 1

User475983607 posted

Ask the users if they want big or little endian.  IMHO, this question is out-of-scope for an ASP forum though.  

    class Program
    {
        static void Main(string[] args)
        {
            string temp = new string('A', 0xABCD);
            byte[] message = BuildMessage(temp);
        }

        private static byte[] BuildMessage(String data)
        {
            // Convert the string data to byte data using ASCII encoding. 
            byte[] byteData = Encoding.ASCII.GetBytes(data);

            if ((byteData.Count() & 0xFF0000) > 1)
            {
                throw new ArgumentOutOfRangeException("Message cannot be larger than 0xFFFF bytes.");
            }

            int length = byteData.Count();
            Console.WriteLine("{0:X} ({0})", length);
            Console.WriteLine();

            List<byte> littleEndian = new List<byte>() { (byte)(length & 0xFF), (byte)((length >> 8) & 0xFF) };
            littleEndian.AddRange(byteData);

            List<byte> bigEndian = new List<byte>() { (byte)((length >> 8) & 0xFF), (byte)(length & 0xFF) };
            bigEndian.AddRange(byteData);


            Console.WriteLine("Little Endian");
            Console.WriteLine("Length:\t{0}", littleEndian.Count());
            Console.WriteLine("Byte[0]:\t{0:X}", littleEndian[0]);
            Console.WriteLine("Byte[1]:\t{0:X}", littleEndian[1]);
            Console.WriteLine("Byte[2]:\t{0:X}", littleEndian[2]);

            Console.WriteLine();
            Console.WriteLine("Big Endian");
            Console.WriteLine("Length:\t{0}", bigEndian.Count());
            Console.WriteLine("Byte[0]:\t{0:X}", bigEndian[0]);
            Console.WriteLine("Byte[1]:\t{0:X}", bigEndian[1]);
            Console.WriteLine("Byte[2]:\t{0:X}", bigEndian[2]);


            return littleEndian.ToArray();

        }
    }

ABCD (43981)

Little Endian
Length: 43983
Byte[0]:        CD
Byte[1]:        AB
Byte[2]:        41

Big Endian
Length: 43983
Byte[0]:        AB
Byte[1]:        CD
Byte[2]:        41