/// <summary>
/// Handles a connect packet
/// </summary>
/// <param name="connect">Connect.</param>
private void HandleConnect(UdpConnect connect, EndPoint endpoint)
{
var ipEndpoint = (IPEndPoint)endpoint;
//var address = ipEndpoint.Address;
if (availablePorts.Count == 0) // no available ports
{
Send(new UdpDisconnect(connect.clientSalt, UdpDisconnectReason.ServerFull), endpoint);
return;
}
if (connections.TryGetValue(ipEndpoint, out var connection))
{
Send(new UdpDisconnect(connect.clientSalt, UdpDisconnectReason.ExistingConnection), endpoint);
return;
}
var state = CreateConnectionRequest(connect.clientSalt, ipEndpoint);
requestStates[ipEndpoint] = state;
var saltSolution = Udp.CreateSalt(state.clientSalt, state.serverSalt);
Send(new UdpChallenge(state.clientSalt, state.serverSalt), endpoint);
}
/// <summary>
/// Handles a solution packet
/// </summary>
/// <param name="solution">Solution.</param>
private void HandleSolution(UdpSolution solution, EndPoint endpoint)
{
var ipEndpoint = (IPEndPoint)endpoint;
var address = ipEndpoint.Address;
if (connections.TryGetValue(ipEndpoint, out var oldcon))
{
if (oldcon.salt != solution.salt)
{
Log.Write("New connection failed: already an existing connection");
return;
}
Send(new UdpConnected(oldcon.salt, (ushort)oldcon.LocalPort), endpoint);
return;
}
if (!requestStates.TryGetValue(ipEndpoint, out var state))
{
Log.Write("New connection failed: no request state found");
return;
}
var saltSolution = Udp.CreateSalt(state.clientSalt, state.serverSalt);
if (solution.salt != saltSolution)
{
Log.Write("New connection failed: salt solution invalid");
return;
}
if (!requestStates.TryRemove(ipEndpoint, out state))
{
Log.Write("New connection failed: no request state to remove");
return;
}
if (!availablePorts.TryDequeue(out int port))
{
Log.Write("New connection failed: failed to assign port");
return;
}
var connection = (TCon)Activator.CreateInstance(typeof(TCon));
if (!connections.TryAdd(ipEndpoint, connection))
{
availablePorts.Enqueue(port); // return port
connection.Disconnect(UdpDisconnectReason.Custom, true, "Failed to add connection");
Log.Write("New connection failed: failed to add connection");
return;
}
connection.SetConnectedTo(endpoint, saltSolution, port);
connection.OnDisconnect += ClientDisconnected;
HandleConnection(connection);
connection.StartRead();
Send(new UdpConnected(saltSolution, (ushort)port), endpoint);
}
/// <summary>
/// Responds to a challenge packet received from the remote server
/// </summary>
/// <param name="challenge">Challenge.</param>
private void HandleChallenge(UdpChallenge challenge)
{
if (challenge.clientSalt != localSalt)
{
return; // salt mismatch, could be spoofed sender
}
if (!SetConnectionState(ConnectionState.AwaitingConnected, ConnectionState.AwaitingChallenge))
{
return;
}
remoteSalt = challenge.serverSalt;
salt = Udp.CreateSalt(localSalt, remoteSalt);
retryCount = 0;
SendSolution();
}
