private KeyValuePair<TransferBuffer, Packet> GetPacketToSend()
{
if (m_outgoing_packets.Count == 0)
{
throw (new Exception("[SecurityAPI::GetPacketToSend] No packets are avaliable to send."));
}
Packet packet = m_outgoing_packets[0];
m_outgoing_packets.RemoveAt(0);
if (packet.Massive)
{
ushort parts = 0;
PacketWriter final = new PacketWriter();
PacketWriter final_data = new PacketWriter();
byte[] input_data = packet.GetBytes();
PacketReader input_reader = new PacketReader(input_data);
TransferBuffer workspace = new TransferBuffer(4089, 0, (int)input_data.Length);
while (workspace.Size > 0)
{
PacketWriter part_data = new PacketWriter();
int cur_size = workspace.Size > 4089 ? 4089 : workspace.Size; // Max buffer size is 4kb for the client
part_data.Write((byte)0); // Data flag
part_data.Write(input_data, workspace.Offset, cur_size);
workspace.Offset += cur_size;
workspace.Size -= cur_size; // Update the size
final_data.Write(FormatPacket(0x600D, part_data.GetBytes(), false));
++parts; // Track how many parts there are
}
// Write the final header packet to the front of the packet
PacketWriter final_header = new PacketWriter();
final_header.Write((byte)1); // Header flag
final_header.Write((short)parts);
final_header.Write(packet.Opcode);
final.Write(FormatPacket(0x600D, final_header.GetBytes(), false));
// Finish the large packet of all the data
final.Write(final_data.GetBytes());
// Return the collated data
byte[] raw_bytes = final.GetBytes();
packet.Lock();
return new KeyValuePair<TransferBuffer, Packet>(new TransferBuffer(raw_bytes, 0, raw_bytes.Length, true), packet);
}
else
{
bool encrypted = packet.Encrypted;
if (!m_client_security)
{
if (m_enc_opcodes.Contains(packet.Opcode))
{
encrypted = true;
}
}
byte[] raw_bytes = FormatPacket(packet.Opcode, packet.GetBytes(), encrypted);
packet.Lock();
return new KeyValuePair<TransferBuffer, Packet>(new TransferBuffer(raw_bytes, 0, raw_bytes.Length, true), packet);
}
}
private byte[] FormatPacket(ushort opcode, byte[] data, bool encrypted)
{
// Sanity check
if (data.Length >= 0x8000)
{
throw (new Exception("[SecurityAPI::FormatPacket] Payload is too large!"));
}
ushort data_length = (ushort)data.Length;
// Add the packet header to the start of the data
PacketWriter writer = new PacketWriter();
writer.Write(data_length); // packet size
writer.Write(opcode); // packet opcode
writer.Write((ushort)0); // packet security bytes
writer.Write(data);
writer.Flush();
// Determine if we need to mark the packet size as encrypted
if (encrypted && (m_security_flags.blowfish == 1 || (m_security_flags.security_bytes == 1 && m_security_flags.blowfish == 0)))
{
long seek_index = writer.BaseStream.Seek(0, SeekOrigin.Current);
ushort packet_size = (ushort)(data_length | 0x8000);
writer.BaseStream.Seek(0, SeekOrigin.Begin);
writer.Write((ushort)packet_size);
writer.Flush();
writer.BaseStream.Seek(seek_index, SeekOrigin.Begin);
}
// Only need to stamp bytes if this is a clientless object
if (m_client_security == false && m_security_flags.security_bytes == 1)
{
long seek_index = writer.BaseStream.Seek(0, SeekOrigin.Current);
byte sb1 = GenerateCountByte(true);
writer.BaseStream.Seek(4, SeekOrigin.Begin);
writer.Write(sb1);
writer.Flush();
byte sb2 = GenerateCheckByte(writer.GetBytes());
writer.BaseStream.Seek(5, SeekOrigin.Begin);
writer.Write(sb2);
writer.Flush();
writer.BaseStream.Seek(seek_index, SeekOrigin.Begin);
}
// If the packet should be physically encrypted, return an encrypted version of it
if (encrypted && m_security_flags.blowfish == 1)
{
byte[] raw_data = writer.GetBytes();
byte[] encrypted_data = m_blowfish.Encode(raw_data, 2, raw_data.Length - 2);
writer.BaseStream.Seek(2, SeekOrigin.Begin);
writer.Write(encrypted_data);
writer.Flush();
}
else
{
// Determine if we need to unmark the packet size from being encrypted but not physically encrypted
if (encrypted && (m_security_flags.security_bytes == 1 && m_security_flags.blowfish == 0))
{
long seek_index = writer.BaseStream.Seek(0, SeekOrigin.Current);
writer.BaseStream.Seek(0, SeekOrigin.Begin);
writer.Write((ushort)data_length);
writer.Flush();
writer.BaseStream.Seek(seek_index, SeekOrigin.Begin);
}
}
// Return the final data
return writer.GetBytes();
}
