// Try to decrypt incoming data.
public void DecodeIncomingPacket(NetState from, ref byte[] buffer, ref int length)
{
#region m_Encryption != null
if (m_Encryption != null)
{
// If we're decrypting using LoginCrypt and we've already been relayed,
// only decrypt a single packet using logincrypt and then disable it
if (m_AlreadyRelayed && m_Encryption is LoginEncryption)
{
uint newSeed = ((((LoginEncryption)(m_Encryption)).Key1 + 1) ^ ((LoginEncryption)(m_Encryption)).Key2);
// Swap the seed
newSeed = ((newSeed >> 24) & 0xFF) | ((newSeed >> 8) & 0xFF00) | ((newSeed << 8) & 0xFF0000) | ((newSeed << 24) & 0xFF000000);
// XOR it with the old seed
newSeed ^= m_Seed;
IClientEncryption newEncryption = new GameEncryption(newSeed);
// Game Encryption comes first
newEncryption.ClientDecrypt(ref buffer, length);
// The login encryption is still used for this one packet
m_Encryption.ClientDecrypt(ref buffer, length);
// Swap the encryption schemes
m_Encryption = newEncryption;
m_Seed = newSeed;
return;
}
m_Encryption.ClientDecrypt(ref buffer, length);
return;
}
#endregion
#region Port Scan
bool handle = false;
for (int i = 0; i < Listener.EndPoints.Length; i++)
{
IPEndPoint ipep = Listener.EndPoints[i];
if (((IPEndPoint)from.Socket.LocalEndPoint).Port == ipep.Port)
{
handle = true;
}
}
if (!handle)
{
m_Encryption = new NoEncryption();
return;
}
#endregion
#region !m_Seeded
// For simplicities sake, enqueue what we just received as long as we're not initialized
m_Buffer.Enqueue(buffer, 0, length);
// Clear the array
length = 0;
if (!m_Seeded)
{
if ((m_Buffer.Length == 83 || m_Buffer.Length == 21) && (m_Buffer.GetPacketID() == 239)) //New Client
{
length = m_Buffer.Length;
byte[] m_Peek = new byte[21];
m_Buffer.Dequeue(m_Peek, 0, 21);
m_Seed = (uint)((m_Peek[1] << 24) | (m_Peek[2] << 16) | (m_Peek[3] << 8) | m_Peek[4]);
m_Seeded = true;
Buffer.BlockCopy(m_Peek, 0, buffer, 0, 21);
// We need to wait the next packet
if (length == 21)
{
return;
}
length = 21;
}
else if (m_Buffer.Length >= 4) // Old Client
{
byte[] m_Peek = new byte[4];
m_Buffer.Dequeue(m_Peek, 0, 4);
m_Seed = (uint)((m_Peek[0] << 24) | (m_Peek[1] << 16) | (m_Peek[2] << 8) | m_Peek[3]);
m_Seeded = true;
Buffer.BlockCopy(m_Peek, 0, buffer, 0, 4);
length = 4;
}
else
{
//Console.WriteLine("Encryption: Failed - Invalid Client.");
return;
}
}
#endregion
// If the context isn't initialized yet, that means we haven't decided on an encryption method yet
#region m_Encryption == null
if (m_Encryption == null)
{
int packetLength = m_Buffer.Length;
int packetOffset = length;
m_Buffer.Dequeue(buffer, length, packetLength); // Dequeue everything
length += packetLength;
// This is special handling for the "special" UOG packet
if (packetLength >= 3)
{
if (buffer[packetOffset] == 0xf1 && buffer[packetOffset + 1] == ((packetLength >> 8) & 0xFF) && buffer[packetOffset + 2] == (packetLength & 0xFF))
{
m_Encryption = new NoEncryption();
return;
}
}
// Check if the current buffer contains a valid login packet (62 byte + 4 byte header)
// Please note that the client sends these in two chunks. One 4 byte and one 62 byte.
if (packetLength == 62)
{
// Check certain indices in the array to see if the given data is unencrypted
if (buffer[packetOffset] == 0x80 && buffer[packetOffset + 30] == 0x00 && buffer[packetOffset + 60] == 0x00)
{
if (Configuration.AllowUnencryptedClients)
{
m_Encryption = new NoEncryption();
}
else
{
RejectNoEncryption(from);
from.Dispose();
return;
}
}
else
{
LoginEncryption encryption = new LoginEncryption();
if (encryption.Initialize(m_Seed, buffer, packetOffset, packetLength, from))
{
Console.WriteLine("Client: {0}: Encrypted client detected, using keys for client v{1}.", from, encryption.Name);
m_Encryption = encryption;
byte[] packet = new byte[packetLength];
Buffer.BlockCopy(buffer, packetOffset, packet, 0, packetLength);
encryption.ClientDecrypt(ref packet, packet.Length);
Buffer.BlockCopy(packet, 0, buffer, packetOffset, packetLength);
}
else
{
Console.WriteLine("Client: Unknown client detected, disconnecting.");
from.Dispose();
}
}
}
else if (packetLength == 65)
{
// If its unencrypted, use the NoEncryption class
if (buffer[packetOffset] == '\x91' && buffer[packetOffset + 1] == ((m_Seed >> 24) & 0xFF) && buffer[packetOffset + 2] == ((m_Seed >> 16) & 0xFF) && buffer[packetOffset + 3] == ((m_Seed >> 8) & 0xFF) && buffer[packetOffset + 4] == (m_Seed & 0xFF))
{
if (Configuration.AllowUnencryptedClients)
{
m_Encryption = new NoEncryption();
}
else
{
RejectNoEncryption(from);
}
}
else
{
// If it's not an unencrypted packet, simply assume it's encrypted with the seed
m_Encryption = new GameEncryption(m_Seed);
byte[] packet = new byte[packetLength];
Buffer.BlockCopy(buffer, packetOffset, packet, 0, packetLength);
m_Encryption.ClientDecrypt(ref packet, packet.Length);
Buffer.BlockCopy(packet, 0, buffer, packetOffset, packetLength);
}
}
// If it's still not initialized, copy the data back to the queue and wait for more
if (m_Encryption == null)
{
m_Buffer.Enqueue(buffer, packetOffset, packetLength);
length -= packetLength;
return;
}
}
#endregion
}
