/// <summary>
/// UDP event handler. Called when a UDP packet is waiting to be read
/// </summary>
/// <param name="ar"></param>
protected void RecvFromCallback(IAsyncResult ar)
{
if (m_status != eGameServerStatus.GSS_Open)
return;
if (ar == null)
return;
var server = (GameServer) ar.AsyncState;
Socket s = server.UDPSocket;
GameClient client = null;
if (s != null)
{
//Creates a temporary EndPoint to pass to EndReceiveFrom.
EndPoint tempRemoteEP = new IPEndPoint(IPAddress.Any, 0);
bool receiving = false;
try
{
// Handle the packet
int read = s.EndReceiveFrom(ar, ref tempRemoteEP);
if (read == 0)
{
log.Debug("UDP received bytes = 0");
}
else
{
int pakCheck = (server.UDPBuffer[read - 2] << 8) | server.UDPBuffer[read - 1];
int calcCheck = PacketProcessor.CalculateChecksum(server.UDPBuffer, 0, read - 2);
if (calcCheck != pakCheck)
{
if (log.IsWarnEnabled)
log.WarnFormat("Bad UDP packet checksum (packet:0x{0:X4} calculated:0x{1:X4}) -> ignored", pakCheck, calcCheck);
if (log.IsDebugEnabled)
log.Debug(Marshal.ToHexDump("UDP buffer dump, received " + read + "bytes", server.UDPBuffer));
}
else
{
var sender = (IPEndPoint) (tempRemoteEP);
var pakin = new GSPacketIn(read - GSPacketIn.HDR_SIZE);
pakin.Load(server.UDPBuffer, 0, read);
//Get the next message
BeginReceiveUDP(s, server);
receiving = true;
client = WorldMgr.GetClientFromID(pakin.SessionID);
if (client != null)
{
//If this is the first message from the client, we
//save the endpoint!
if (client.UdpEndPoint == null)
{
client.UdpEndPoint = sender;
client.UdpConfirm = false;
}
//Only handle the packet if it comes from a valid client
if (client.UdpEndPoint.Equals(sender))
{
client.PacketProcessor.HandlePacket(pakin);
}
}
else if (log.IsErrorEnabled)
{
log.Error(
string.Format("Got an UDP packet from invalid client id or ip: client id = {0}, ip = {1}, code = {2:x2}",
pakin.SessionID, sender, pakin.ID));
}
}
}
}
catch (SocketException)
{
}
catch (ObjectDisposedException)
{
}
catch (Exception e)
{
if (log.IsErrorEnabled)
log.Error("RecvFromCallback", e);
}
finally
{
if (!receiving)
{
//Get the next message
//Even if we have errors, we need to continue with UDP
BeginReceiveUDP(s, server);
}
}
}
}
