private void ProcessUdpRequestAsync(object parameter)
{
object[] parameters = parameter as object[];
Socket udpListener = parameters[0] as Socket;
EndPoint remoteEP = parameters[1] as EndPoint;
IPPacketInformation ipPacketInformation = (IPPacketInformation)parameters[2];
DhcpMessage request = parameters[3] as DhcpMessage;
try
{
DhcpMessage response = ProcessDhcpMessage(request, remoteEP as IPEndPoint, ipPacketInformation);
//send response
if (response != null)
{
byte[] sendBuffer = new byte[1024];
MemoryStream sendBufferStream = new MemoryStream(sendBuffer);
response.WriteTo(sendBufferStream);
//send dns datagram
if (!request.RelayAgentIpAddress.Equals(IPAddress.Any))
{
//received request via relay agent so send unicast response to relay agent on port 67
udpListener.SendTo(sendBuffer, 0, (int)sendBufferStream.Position, SocketFlags.None, new IPEndPoint(request.RelayAgentIpAddress, 67));
}
else if (!request.ClientIpAddress.Equals(IPAddress.Any))
{
//client is already configured and renewing lease so send unicast response on port 68
udpListener.SendTo(sendBuffer, 0, (int)sendBufferStream.Position, SocketFlags.None, new IPEndPoint(request.ClientIpAddress, 68));
}
else
{
//send response as broadcast on port 68 on appropriate interface bound socket
if (!_udpListeners.TryGetValue(response.NextServerIpAddress, out Socket udpSocket))
{
udpSocket = udpListener; //no appropriate socket found so use default socket
}
udpSocket.SendTo(sendBuffer, 0, (int)sendBufferStream.Position, SocketFlags.DontRoute, new IPEndPoint(IPAddress.Broadcast, 68)); //no routing for broadcast
}
}
}
catch (ObjectDisposedException)
{
//socket disposed
}
catch (Exception ex)
{
if ((_state == ServiceState.Stopping) || (_state == ServiceState.Stopped))
{
return; //server stopping
}
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP as IPEndPoint, ex);
}
}
}
private async Task ProcessDhcpRequestAsync(DhcpMessage request, IPEndPoint remoteEP, IPPacketInformation ipPacketInformation, Socket udpListener)
{
try
{
DhcpMessage response = await ProcessDhcpMessageAsync(request, remoteEP, ipPacketInformation);
//send response
if (response != null)
{
byte[] sendBuffer = new byte[1024];
MemoryStream sendBufferStream = new MemoryStream(sendBuffer);
response.WriteTo(sendBufferStream);
//send dns datagram
if (!request.RelayAgentIpAddress.Equals(IPAddress.Any))
{
//received request via relay agent so send unicast response to relay agent on port 67
await udpListener.SendToAsync(sendBuffer, 0, (int)sendBufferStream.Position, new IPEndPoint(request.RelayAgentIpAddress, 67));
}
else if (!request.ClientIpAddress.Equals(IPAddress.Any))
{
//client is already configured and renewing lease so send unicast response on port 68
await udpListener.SendToAsync(sendBuffer, 0, (int)sendBufferStream.Position, new IPEndPoint(request.ClientIpAddress, 68));
}
else
{
Socket udpSocket;
//send response as broadcast on port 68 on appropriate interface bound socket
if (_udpListeners.TryGetValue(response.NextServerIpAddress, out UdpListener listener))
{
udpSocket = listener.Socket; //found scope specific socket
}
else
{
udpSocket = udpListener; //no appropriate socket found so use default socket
}
await udpSocket.SendToAsync(sendBuffer, 0, (int)sendBufferStream.Position, new IPEndPoint(IPAddress.Broadcast, 68), SocketFlags.DontRoute); //no routing for broadcast
}
}
}
catch (ObjectDisposedException)
{
//socket disposed
}
catch (Exception ex)
{
if ((_state == ServiceState.Stopping) || (_state == ServiceState.Stopped))
{
return; //server stopping
}
LogManager log = _log;
if (log != null)
{
log.Write(remoteEP, ex);
}
}
}
