private void OnDataReceieve(IAsyncResult result)
{
EndPoint clientEndPoint = new IPEndPoint(IPAddress.Any, 0);
byte[] data;
try
{
int dataSize = Socket.EndReceiveFrom(result, ref clientEndPoint);
data = new byte[dataSize];
Buffer.BlockCopy(buffer, 0, data, 0, dataSize);
}
catch (Exception exception)
{
Console.WriteLine(exception.Message);
return;
}
var session = WorldManager.Find((IPEndPoint)clientEndPoint);
var packet = new ClientPacket(data);
PacketManager.HandlePacket(listenerType, packet, session);
#region DEBUG
uint issacXor;
uint checksum = packet.CalculateChecksum(session, listenerType, 0u, out issacXor);
Console.WriteLine($"Received({listenerType.ToString()}): Size: {data.Length}, Hash: 0x{checksum.ToString("X8")} 0x{ packet.Header.Checksum.ToString("X8")}, Fragments: {packet.Fragments.Count}, Flags: {packet.Header.Flags}");
#endregion
Listen();
}
public static void HandlePacket(ConnectionType type, ClientPacket packet, Session session)
{
// CLinkStatusAverages::OnPingResponse
if (packet.Header.HasFlag(PacketHeaderFlags.EchoRequest))
{
var connectionData = (type == ConnectionType.Login ? session.LoginConnection : session.WorldConnection);
// used to calculate round trip time (ping)
// client calculates: currentTime - requestTime - serverDrift
var echoResponse = new ServerPacket((ushort)(type == ConnectionType.Login ? 0x0B : 0x18), PacketHeaderFlags.EncryptedChecksum | PacketHeaderFlags.EchoResponse);
echoResponse.Payload.Write(packet.HeaderOptional.ClientTime);
echoResponse.Payload.Write((float)connectionData.ServerTime - packet.HeaderOptional.ClientTime);
NetworkManager.SendPacket(type, echoResponse, session);
}
// ClientNet::HandleTimeSynch
if (packet.Header.HasFlag(PacketHeaderFlags.TimeSynch))
{
var connectionData = (type == ConnectionType.Login ? session.LoginConnection : session.WorldConnection);
// used to update time at client and check for overspeed (60s desync and client will disconenct with speed hack warning)
var timeSynchResponse = new ServerPacket((ushort)(type == ConnectionType.Login ? 0x0B : 0x18), PacketHeaderFlags.EncryptedChecksum | PacketHeaderFlags.TimeSynch);
timeSynchResponse.Payload.Write(connectionData.ServerTime);
NetworkManager.SendPacket(type, timeSynchResponse, session);
}
if (packet.Header.HasFlag(PacketHeaderFlags.RequestRetransmit))
{
foreach (uint sequence in packet.HeaderOptional.RetransmitData)
{
CachedPacket cachedPacket;
if (session.CachedPackets.TryGetValue(sequence, out cachedPacket))
{
if (!cachedPacket.Packet.Header.HasFlag(PacketHeaderFlags.Retransmission))
{
cachedPacket.Packet.Header.Flags |= PacketHeaderFlags.Retransmission;
uint issacXor;
cachedPacket.Packet.Header.Checksum = packet.CalculateChecksum(session, ConnectionType.World, cachedPacket.IssacXor, out issacXor);
}
NetworkManager.SendPacketDirect(ConnectionType.World, cachedPacket.Packet, session);
}
}
}
if (type == ConnectionType.Login)
{
if (packet.Header.HasFlag(PacketHeaderFlags.LoginRequest))
{
AuthenticationHandler.HandleLoginRequest(packet, session);
return;
}
if (packet.Header.HasFlag(PacketHeaderFlags.ConnectResponse) && session.Authenticated)
{
AuthenticationHandler.HandleConnectResponse(packet, session);
return;
}
}
else
{
if (packet.Header.HasFlag(PacketHeaderFlags.WorldLoginRequest))
{
AuthenticationHandler.HandleWorldLoginRequest(packet, session);
return;
}
if (packet.Header.HasFlag(PacketHeaderFlags.ConnectResponse))
{
AuthenticationHandler.HandleWorldConnectResponse(packet, session);
return;
}
}
if (packet.Header.HasFlag(PacketHeaderFlags.Disconnect))
{
HandleDisconnectResponse(packet, session);
}
foreach (ClientPacketFragment fragment in packet.Fragments)
{
var opcode = (FragmentOpcode)fragment.Payload.ReadUInt32();
if (!fragmentHandlers.ContainsKey(opcode))
{
Console.WriteLine($"Received unhandled fragment opcode: 0x{((uint)opcode).ToString("X4")}");
}
else
{
FragmentHandler fragmentHandler;
if (fragmentHandlers.TryGetValue(opcode, out fragmentHandler))
{
fragmentHandler.Invoke(fragment, session);
}
}
}
}
public static void HandlePacket(ConnectionType type, ClientPacket packet, Session session)
{
if (!CheckPacketHeader(packet, session))
{
// server treats all packets sent during the first 30 seconds as invalid packets due to server crash, this will move clients to the disconnect screen
if (DateTime.Now < WorldManager.WorldStartTime.AddSeconds(30d))
{
session.SendCharacterError(CharacterError.ServerCrash);
}
return;
}
// CLinkStatusAverages::OnPingResponse
if (packet.Header.HasFlag(PacketHeaderFlags.EchoRequest))
{
var connectionData = (type == ConnectionType.Login ? session.LoginConnection : session.WorldConnection);
// used to calculate round trip time (ping)
// client calculates: currentTime - requestTime - serverDrift
var echoResponse = new ServerPacket((ushort)(type == ConnectionType.Login ? 0x0B : 0x18), PacketHeaderFlags.EncryptedChecksum | PacketHeaderFlags.EchoResponse);
echoResponse.Payload.Write(packet.HeaderOptional.ClientTime);
echoResponse.Payload.Write((float)connectionData.ServerTime - packet.HeaderOptional.ClientTime);
NetworkManager.SendPacket(type, echoResponse, session);
}
// ClientNet::HandleTimeSynch
if (packet.Header.HasFlag(PacketHeaderFlags.TimeSynch))
{
var connectionData = (type == ConnectionType.Login ? session.LoginConnection : session.WorldConnection);
// used to update time at client and check for overspeed (60s desync and client will disconenct with speed hack warning)
var timeSynchResponse = new ServerPacket((ushort)(type == ConnectionType.Login ? 0x0B : 0x18), PacketHeaderFlags.EncryptedChecksum | PacketHeaderFlags.TimeSynch);
timeSynchResponse.Payload.Write(connectionData.ServerTime);
NetworkManager.SendPacket(type, timeSynchResponse, session);
}
if (packet.Header.HasFlag(PacketHeaderFlags.RequestRetransmit))
{
foreach (uint sequence in packet.HeaderOptional.RetransmitData)
{
CachedPacket cachedPacket;
if (session.CachedPackets.TryGetValue(sequence, out cachedPacket))
{
if (!cachedPacket.Packet.Header.HasFlag(PacketHeaderFlags.Retransmission))
{
cachedPacket.Packet.Header.Flags |= PacketHeaderFlags.Retransmission;
uint issacXor;
cachedPacket.Packet.Header.Checksum = packet.CalculateChecksum(session, ConnectionType.World, cachedPacket.IssacXor, out issacXor);
}
NetworkManager.SendPacketDirect(ConnectionType.World, cachedPacket.Packet, session);
}
}
}
if (packet.Header.HasFlag(PacketHeaderFlags.LoginRequest))
{
AuthenticationHandler.HandleLoginRequest(packet, session);
return;
}
if (packet.Header.HasFlag(PacketHeaderFlags.WorldLoginRequest))
{
AuthenticationHandler.HandleWorldLoginRequest(packet, session);
return;
}
if (packet.Header.HasFlag(PacketHeaderFlags.ConnectResponse))
{
if (type == ConnectionType.Login)
{
AuthenticationHandler.HandleConnectResponse(packet, session);
return;
}
AuthenticationHandler.HandleWorldConnectResponse(packet, session);
return;
}
if (packet.Header.HasFlag(PacketHeaderFlags.Disconnect))
{
HandleDisconnectResponse(packet, session);
}
foreach (ClientPacketFragment fragment in packet.Fragments)
{
var opcode = (FragmentOpcode)fragment.Payload.ReadUInt32();
if (!fragmentHandlers.ContainsKey(opcode))
{
Console.WriteLine($"Received unhandled fragment opcode: 0x{(uint)opcode:X4}");
}
else
{
FragmentHandlerInfo fragmentHandlerInfo;
if (fragmentHandlers.TryGetValue(opcode, out fragmentHandlerInfo))
{
if (fragmentHandlerInfo.Attribute.State == session.State)
{
fragmentHandlerInfo.Handler.Invoke(fragment, session);
}
}
}
}
}
