/// <summary>
/// Serlialize this routing option into something which
/// can be passed to a TcpPacket class.
/// </summary>
/// <returns>
/// An InternetProtocolOption class which can be passed to an IpV4Packet.
/// </returns>
public TcpOption Serialize()
{
TcpOption newOption = new TcpOption();
newOption.OptionType = TcpOptionNumber.MaximumSegmentSize;
newOption.Length = 4;
newOption.Data = BitConverter.GetBytes(m_maxSegmentSize);
return(newOption);
}
/// <summary>
/// Create a new max segment size option.
/// </summary>
/// <param name="option">
/// The option to parse.
/// </param>
/// <exception cref="ArgumentNullException">
/// The option argument is null.
/// </exception>
/// <exception cref="ArgumentException">
/// The option argument is not a max segment size option.
/// </exception>
public TcpMaxSegmentSizeOption(TcpOption option)
{
if (option == null)
{
throw new ArgumentNullException("option");
}
if (option.OptionType != TcpOptionNumber.MaximumSegmentSize)
{
throw new ArgumentException("The option passed was not compatible with this class. This class accepts max segment size options only", "option");
}
m_maxSegmentSize = BitConverter.ToUInt16(option.Data, 0);
}
/// <summary>
/// Create a new max segment size option.
/// </summary>
/// <param name="option">
/// The option to parse.
/// </param>
/// <exception cref="ArgumentNullException">
/// The option argument is null.
/// </exception>
/// <exception cref="ArgumentException">
/// The option argument is not a max segment size option.
/// </exception>
public TcpMaxSegmentSizeOption(TcpOption option)
{
if (option == null)
{
throw new ArgumentNullException ("option");
}
if (option.OptionType != TcpOptionNumber.MaximumSegmentSize)
{
throw new ArgumentException ("The option passed was not compatible with this class. This class accepts max segment size options only", "option");
}
m_maxSegmentSize = BitConverter.ToUInt16 (option.Data, 0);
}
/// <summary>
/// Create a new Tcp packet.
/// </summary>
/// <param name="data">
/// The byte array representing the Tcp packet.
/// </param>
public TcpPacket (byte[] data)
{
int position = 0;
#region Basic Fields
// first extract the source port, remembering to convert it to host order
m_sourcePort = (ushort)IPAddress.NetworkToHostOrder (BitConverter.ToInt16 (data, position));
position += 2;
// same with the destination port
m_destPort = (ushort)IPAddress.NetworkToHostOrder (BitConverter.ToInt16 (data, position));
position += 2;
// now extract the sequence number, again converting to host order
m_sequenceNumber = (uint)IPAddress.NetworkToHostOrder (BitConverter.ToInt32 (data, position));
position += 4;
// same witht he acknowledgment number
m_acknowledgmentNumber = (uint)IPAddress.NetworkToHostOrder (BitConverter.ToInt32 (data, position));
position += 4;
// copy out the data offset. This is the upper 3 bits of the next byte
// we also multiply it by 4 since this the value returned is the number of
// 32 bit words.
m_offset = (ushort)((data[position] >> 4) * 4);
position++;
// now extract the flags field. These are stored in the lower 6 bits of the next byte
m_flags = (byte)(data[position] & 0x3f);
position++;
// copy out the window field and convert it to host order
m_window = (ushort)IPAddress.NetworkToHostOrder (BitConverter.ToInt16 (data, position));
position += 2;
// same again for the checksum
m_checksum = (ushort)IPAddress.NetworkToHostOrder (BitConverter.ToInt16 (data, position));
position += 2;
// and the same for the urgent pointer
m_urgentPointer = (ushort)IPAddress.NetworkToHostOrder (BitConverter.ToInt16 (data, position));
position += 2;
#endregion
#region Options and Padding
// a header length of more than 20 bytes indicates that there are some options
if (m_offset > 0x14)
{
// create a new buffer of the correct size and copy the options into it
byte[] optionsAndPadding = new byte[m_offset - 0x14];
Array.Copy (data, position, optionsAndPadding, 0, optionsAndPadding.Length);
// go through each byte of the options
for (int i = 0; i < optionsAndPadding.Length;)
{
TcpOption option = new TcpOption ();
// fill in basic fields
option.OptionType = (TcpOptionNumber)optionsAndPadding[i];
i++;
#region Fill in Basic Option Fields
if (option.OptionType == TcpOptionNumber.EndOfOptions)
{
// copy the padding field out of the header
if (optionsAndPadding.Length - i > 0)
{
m_padding = new byte[optionsAndPadding.Length - i];
Array.Copy (optionsAndPadding, i, m_padding, 0, m_padding.Length);
}
// add this option to the array
option.Length = 1;
}
else if (option.OptionType != TcpOptionNumber.NoOperation)
{
// copy out the length field
option.Length = (int)(optionsAndPadding[i]);
option.Data = new byte[option.Length - 2];
// copy the actual data out of the packet
i++;
Array.Copy (optionsAndPadding, i, option.Data, 0, option.Data.Length);
// add this new option to the array
i += option.Data.Length;
}
else
{
option.Length = 1;
}
#endregion
#region Add Option
if (m_options == null)
{
m_options = new TcpOption[1];
}
else
{
TcpOption[] tempOptions = new TcpOption[m_options.Length];
Array.Copy (m_options, 0, tempOptions, 0, m_options.Length);
m_options = new TcpOption[m_options.Length + 1];
Array.Copy (tempOptions, 0, m_options, 0, tempOptions.Length);
m_options[m_options.Length - 1] = option;
}
m_options[m_options.Length - 1] = option;
#endregion
if (option.OptionType == TcpOptionNumber.EndOfOptions)
{
break;
}
}
position += optionsAndPadding.Length;
}
#endregion
// now check if there is any data
if (data.Length > m_offset)
{
// allocate a new buffer for it and copy the data in to the buffer
m_data = new byte[data.Length - m_offset];
Array.Copy (data, position, m_data, 0, m_data.Length);
}
}
/// <summary>
/// Create a new Tcp packet.
/// </summary>
/// <param name="data">
/// The byte array representing the Tcp packet.
/// </param>
public TcpPacket(byte[] data)
{
int position = 0;
#region Basic Fields
// first extract the source port, remembering to convert it to host order
m_sourcePort = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(data, position));
position += 2;
// same with the destination port
m_destPort = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(data, position));
position += 2;
// now extract the sequence number, again converting to host order
m_sequenceNumber = (uint)IPAddress.NetworkToHostOrder(BitConverter.ToInt32(data, position));
position += 4;
// same witht he acknowledgment number
m_acknowledgmentNumber = (uint)IPAddress.NetworkToHostOrder(BitConverter.ToInt32(data, position));
position += 4;
// copy out the data offset. This is the upper 3 bits of the next byte
// we also multiply it by 4 since this the value returned is the number of
// 32 bit words.
m_offset = (ushort)((data[position] >> 4) * 4);
position++;
// now extract the flags field. These are stored in the lower 6 bits of the next byte
m_flags = (byte)(data[position] & 0x3f);
position++;
// copy out the window field and convert it to host order
m_window = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(data, position));
position += 2;
// same again for the checksum
m_checksum = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(data, position));
position += 2;
// and the same for the urgent pointer
m_urgentPointer = (ushort)IPAddress.NetworkToHostOrder(BitConverter.ToInt16(data, position));
position += 2;
#endregion
#region Options and Padding
// a header length of more than 20 bytes indicates that there are some options
if (m_offset > 0x14)
{
// create a new buffer of the correct size and copy the options into it
byte[] optionsAndPadding = new byte[m_offset - 0x14];
Array.Copy(data, position, optionsAndPadding, 0, optionsAndPadding.Length);
// go through each byte of the options
for (int i = 0; i < optionsAndPadding.Length;)
{
TcpOption option = new TcpOption();
// fill in basic fields
option.OptionType = (TcpOptionNumber)optionsAndPadding[i];
i++;
#region Fill in Basic Option Fields
if (option.OptionType == TcpOptionNumber.EndOfOptions)
{
// copy the padding field out of the header
if (optionsAndPadding.Length - i > 0)
{
m_padding = new byte[optionsAndPadding.Length - i];
Array.Copy(optionsAndPadding, i, m_padding, 0, m_padding.Length);
}
// add this option to the array
option.Length = 1;
}
else if (option.OptionType != TcpOptionNumber.NoOperation)
{
// copy out the length field
option.Length = (int)(optionsAndPadding[i]);
option.Data = new byte[option.Length - 2];
// copy the actual data out of the packet
i++;
Array.Copy(optionsAndPadding, i, option.Data, 0, option.Data.Length);
// add this new option to the array
i += option.Data.Length;
}
else
{
option.Length = 1;
}
#endregion
#region Add Option
if (m_options == null)
{
m_options = new TcpOption[1];
}
else
{
TcpOption[] tempOptions = new TcpOption[m_options.Length];
Array.Copy(m_options, 0, tempOptions, 0, m_options.Length);
m_options = new TcpOption[m_options.Length + 1];
Array.Copy(tempOptions, 0, m_options, 0, tempOptions.Length);
m_options[m_options.Length - 1] = option;
}
m_options[m_options.Length - 1] = option;
#endregion
if (option.OptionType == TcpOptionNumber.EndOfOptions)
{
break;
}
}
position += optionsAndPadding.Length;
}
#endregion
// now check if there is any data
if (data.Length > m_offset)
{
// allocate a new buffer for it and copy the data in to the buffer
m_data = new byte[data.Length - m_offset];
Array.Copy(data, position, m_data, 0, m_data.Length);
}
}
/// <summary>
/// Serlialize this routing option into something which
/// can be passed to a TcpPacket class.
/// </summary>
/// <returns>
/// An InternetProtocolOption class which can be passed to an IpV4Packet.
/// </returns>
public TcpOption Serialize ()
{
TcpOption newOption = new TcpOption ();
newOption.OptionType = TcpOptionNumber.MaximumSegmentSize;
newOption.Length = 4;
newOption.Data = BitConverter.GetBytes (m_maxSegmentSize);
return newOption;
}
