bool cProtocolRecognizer::TryRecognizeProtocol(void)
{
// NOTE: If a new protocol is added or an old one is removed, adjust MCS_CLIENT_VERSIONS and MCS_PROTOCOL_VERSIONS macros in the header file
// Lengthed protocol, try if it has the entire initial handshake packet:
UInt32 PacketLen;
UInt32 ReadSoFar = static_cast<UInt32>(m_Buffer.GetReadableSpace());
if (!m_Buffer.ReadVarInt(PacketLen))
{
// Not enough bytes for the packet length, keep waiting
return false;
}
ReadSoFar -= static_cast<UInt32>(m_Buffer.GetReadableSpace());
if (!m_Buffer.CanReadBytes(PacketLen))
{
// Not enough bytes for the packet, keep waiting
return false;
}
return TryRecognizeLengthedProtocol(PacketLen - ReadSoFar);
}
bool cProtocolRecognizer::TryRecognizeProtocol(void)
{
// NOTE: If a new protocol is added or an old one is removed, adjust MCS_CLIENT_VERSIONS and
// MCS_PROTOCOL_VERSIONS macros in the header file, as well as PROTO_VERSION_LATEST macro
// The first packet should be a Handshake, 0x02:
unsigned char PacketType;
if (!m_Buffer.ReadByte(PacketType))
{
return false;
}
switch (PacketType)
{
case 0x02: return TryRecognizeLengthlessProtocol(); // Handshake, continue recognizing
case 0xfe:
{
// This may be either a packet length or the length-less Ping packet
Byte NextByte;
if (!m_Buffer.ReadByte(NextByte))
{
// Not enough data for either protocol
// This could actually happen with the 1.2 / 1.3 client, but their support is fading out anyway
return false;
}
if (NextByte != 0x01)
{
// This is definitely NOT a length-less Ping packet, handle as lengthed protocol:
break;
}
if (!m_Buffer.ReadByte(NextByte))
{
// There is no more data. Although this *could* mean TCP fragmentation, it is highly unlikely
// and rather this is a 1.4 client sending a regular Ping packet (without the following Plugin message)
SendLengthlessServerPing();
return false;
}
if (NextByte == 0xfa)
{
// Definitely a length-less Ping followed by a Plugin message
SendLengthlessServerPing();
return false;
}
// Definitely a lengthed Initial handshake, handle below:
break;
}
} // switch (PacketType)
// This must be a lengthed protocol, try if it has the entire initial handshake packet:
m_Buffer.ResetRead();
UInt32 PacketLen;
UInt32 ReadSoFar = (UInt32)m_Buffer.GetReadableSpace();
if (!m_Buffer.ReadVarInt(PacketLen))
{
// Not enough bytes for the packet length, keep waiting
return false;
}
ReadSoFar -= (UInt32)m_Buffer.GetReadableSpace();
if (!m_Buffer.CanReadBytes(PacketLen))
{
// Not enough bytes for the packet, keep waiting
return false;
}
return TryRecognizeLengthedProtocol(PacketLen - ReadSoFar);
}
