/// <summary>
/// Handles a packet, reading the flags and processing all fragments.
/// </summary>
/// <param name="packet">ClientPacket to handle</param>
private void HandlePacket(ClientPacket packet)
{
log.DebugFormat("[{0}] Handling packet {1}", session.Account, packet.Header.Sequence);
uint issacXor = packet.Header.HasFlag(PacketHeaderFlags.EncryptedChecksum) ? ConnectionData.IssacClient.GetOffset() : 0;
if (!packet.VerifyChecksum(issacXor))
{
log.WarnFormat("[{0}] Packet {1} has invalid checksum", session.Account, packet.Header.Sequence);
}
// depending on the current session state:
// Set the next timeout tick value, to compare against in the WorldManager
// Sessions that have gone past the AuthLoginRequest step will stay active for a longer period of time (exposed via configuration)
// Sessions that in the AuthLoginRequest will have a short timeout, as set in the AuthenticationHandler.DefaultAuthTimeout.
// Example: Applications that check uptime will stay in the AuthLoginRequest state.
session.Network.TimeoutTick = (session.State == Enum.SessionState.AuthLoginRequest) ?
DateTime.UtcNow.AddSeconds(WorldManager.DefaultSessionTimeout).Ticks :
DateTime.UtcNow.AddSeconds(AuthenticationHandler.DefaultAuthTimeout).Ticks;
// If we have an EchoRequest flag, we should flag to respond with an echo response on next send.
if (packet.Header.HasFlag(PacketHeaderFlags.EchoRequest))
{
FlagEcho(packet.HeaderOptional.EchoRequestClientTime);
}
// If we have an AcknowledgeSequence flag, we can clear our cached packet buffer up to that sequence.
if (packet.Header.HasFlag(PacketHeaderFlags.AckSequence))
{
AcknowledgeSequence(packet.HeaderOptional.Sequence);
}
if (packet.Header.HasFlag(PacketHeaderFlags.TimeSynch))
{
log.DebugFormat("[{0}] Incoming TimeSync TS: {1}", session.Account, packet.HeaderOptional.TimeSynch);
// Do something with this...
// Based on network traces these are not 1:1. Server seems to send them every 20 seconds per port.
// Client seems to send them alternatingly every 2 or 4 seconds per port.
// We will send this at a 20 second time interval. I don't know what to do with these when we receive them at this point.
}
// If the client is requesting a retransmission, pull those packets from the queue and resend them.
if (packet.Header.HasFlag(PacketHeaderFlags.RequestRetransmit))
{
foreach (uint sequence in packet.HeaderOptional.RetransmitData)
{
Retransmit(sequence);
}
}
// This should be set on the first packet to the server indicating the client is logging in.
// This is the start of a three-way handshake between the client and server (LoginRequest, ConnectRequest, ConnectResponse)
// Note this would be sent to each server a client would connect too (Login and each world).
// In our current implimenation we handle all roles in this one server.
if (packet.Header.HasFlag(PacketHeaderFlags.LoginRequest))
{
AuthenticationHandler.HandleLoginRequest(packet, session);
return;
}
// This should be set on the second packet to the server from the client.
// This completes the three-way handshake.
if (packet.Header.HasFlag(PacketHeaderFlags.ConnectResponse))
{
sendResync = true;
AuthenticationHandler.HandleConnectResponse(packet, session);
return;
}
// Process all fragments out of the packet
foreach (ClientPacketFragment fragment in packet.Fragments)
{
ProcessFragment(fragment);
}
// Update the last received sequence.
if (packet.Header.Sequence != 0)
{
lastReceivedPacketSequence = packet.Header.Sequence;
}
}
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);
}
}
}
}
/// <summary>
/// Handles a packet, reading the flags and processing all fragments.
/// </summary>
/// <param name="packet">ClientPacket to handle</param>
private void HandlePacket(ClientPacket packet)
{
log.DebugFormat("[{0}] Handling packet {1}", session.Account, packet.Header.Sequence);
uint issacXor = packet.Header.HasFlag(PacketHeaderFlags.EncryptedChecksum) ? ConnectionData.IssacClient.GetOffset() : 0;
if (!packet.VerifyChecksum(issacXor))
{
log.WarnFormat("[{0}] Packet {1} has invalid checksum", session.Account, packet.Header.Sequence);
}
// If we have an EchoRequest flag, we should flag to respond with an echo response on next send.
if (packet.Header.HasFlag(PacketHeaderFlags.EchoRequest))
{
FlagEcho(packet.HeaderOptional.EchoRequestClientTime);
}
// If we have an AcknowledgeSequence flag, we can clear our cached packet buffer up to that sequence.
if (packet.Header.HasFlag(PacketHeaderFlags.AckSequence))
{
AcknowledgeSequence(packet.HeaderOptional.Sequence);
}
if (packet.Header.HasFlag(PacketHeaderFlags.TimeSynch))
{
// Do something with this...
// Based on network traces these are not 1:1. Server seems to send them every 20 seconds per port.
// Client seems to send them alternatingly every 2 or 4 seconds per port.
// We will send this at a 20 second time interval. I don't know what to do with these when we receive them at this point.
}
// If the client is requesting a retransmission, pull those packets from the queue and resend them.
if (packet.Header.HasFlag(PacketHeaderFlags.RequestRetransmit))
{
foreach (uint sequence in packet.HeaderOptional.RetransmitData)
{
Retransmit(sequence);
}
}
// This should be set on the first packet to the server indicating the client is logging in.
// This is the start of a three-way handshake between the client and server (LoginRequest, ConnectRequest, ConnectResponse)
// Note this would be sent to each server a client would connect too (Login and each world).
// In our current implimenation we handle all roles in this one server.
if (packet.Header.HasFlag(PacketHeaderFlags.LoginRequest))
{
AuthenticationHandler.HandleLoginRequest(packet, session);
return;
}
// This should be set on the second packet to the server from the client.
// This comletes the three-way handshake.
if (packet.Header.HasFlag(PacketHeaderFlags.ConnectResponse))
{
sendResync = true;
AuthenticationHandler.HandleConnectResponse(packet, session);
return;
}
// Process all fragments out of the packet
foreach (ClientPacketFragment fragment in packet.Fragments)
{
ProcessFragment(fragment);
}
// Update the last received sequence.
if (packet.Header.Sequence != 0)
{
lastReceivedPacketSequence = packet.Header.Sequence;
}
}
private static void HandleDisconnectResponse(ClientPacket packet, Session session)
{
WorldManager.Remove(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);
}
}
}
}
}