/// <summary>
/// Assembles the current outgoing packet from the given payload data, crypto session, auth session and partial header.
/// </summary>
/// <param name="payloadData">The raw payload data.</param>
/// <param name="crypto">The crypto session being used.</param>
/// <param name="auth">The auth session being used.</param>
/// <param name="partialHeader">The outer packet header, except for the 2 first bytes (packet size).</param>
/// <returns>The assembled packet, ready to be sent.</returns>
private static byte[] AssemblePacket(byte[] payloadData, CryptoSession crypto, AuthSession auth, byte[] partialHeader)
{
PayloadReader reader = new PayloadReader(payloadData, 6);
if (reader.ReadBool())
{
payloadData = PayloadCompression.Compress(payloadData);
}
FixSize(payloadData);
byte[] iv = Generate.IV();
byte[] encryptedData = crypto.EncryptPacket(payloadData, iv);
HeaderWriter headerWriter = new HeaderWriter();
headerWriter.WriteData((short)(16 + encryptedData.Length + 10));
headerWriter.WriteData(partialHeader);
headerWriter.WriteData(iv);
byte[] partialBuffer = Sequence.Concat(headerWriter.GetHeader(), encryptedData);
byte[] hmac = auth.GetHmac(partialBuffer);
return(Sequence.Concat(partialBuffer, hmac));
}
/// <summary>
/// Initializes a new instance of OutPacket from the given payload data, crypto session, prefix and count.
/// </summary>
/// <param name="payloadData">The raw payload data.</param>
/// <param name="crypto">The crypto session to be used.</param>
/// <param name="auth">The auth session to be used.</param>
/// <param name="prefix">The packet prefix.</param>
/// <param name="count">The current count of sent packets.</param>
public OutPacket(byte[] payloadData, CryptoSession crypto, AuthSession auth, short prefix, int count)
{
HeaderWriter headerWriter = new HeaderWriter();
headerWriter.WriteData(prefix);
headerWriter.WriteData(count);
Data = AssemblePacket(payloadData, crypto, auth, headerWriter.GetHeader());
}
/// <summary>
/// Initializes a new instance of OutPacket for the keys definition packet (ID 0x0001) from the given
/// payload data, crypto session, auth session and count.
/// </summary>
/// <param name="payloadData">The raw payload data.</param>
/// <param name="crypto">The crypto session to be used.</param>
/// <param name="auth">The auth session to be used.</param>
/// <param name="firstCount">The first packet count.</param>
public OutPacket(byte[] payloadData, CryptoSession crypto, AuthSession auth, int firstCount)
{
HeaderWriter headerWriter = new HeaderWriter();
headerWriter.WriteData((short)(0));
headerWriter.WriteData(firstCount);
Data = AssemblePacket(payloadData, crypto, auth, headerWriter.GetHeader());
}
