public bool FilterPacket(EthernetPacket ethernetPacket)
{
var iface = PacketDispatcher.Instance.GetCurrentInterface();
if (ethernetPacket == null)
{
return(false);
}
// perform basic checks to detect if we have a valid TCP packet
if (ethernetPacket.Type != EthernetPacketType.IpV4)
{
return(false);
}
var ipPacket = (IPv4Packet)ethernetPacket.PayloadPacket;
if (ipPacket.NextHeader != IPProtocolType.TCP)
{
return(false);
}
var tcpPacket = (TcpPacket)ipPacket.PayloadPacket;
if (tcpPacket.DestinationPort != 80)
{
return(false);
}
// get full TCP payload and try to parse it as a HTTP request
var packetData = Encoding.UTF8.GetString(tcpPacket.PayloadData);
var request = HttpRequest.TryParse(packetData);
if (request == null)
{
return(false);
}
// match current request against current filter's settings
if (IsFilterMatch(request))
{
ethernetPacket = PrepareTCPResponse(ethernetPacket, GenerateHTTPRedirect(RedirectTarget));
iface.SendPacket(ethernetPacket);
DebugInformation.WriteLine(String.Format("[FILTER] \"{0}\" applied to client \"{1}\"", Name, ipPacket.DestinationAddress));
return(true);
}
return(false);
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
// load network devices
ComboInterfaces.ItemsSource = NetworkInterfaceList.Instance.GetList();
ComboInterfaces.SelectedItem = NetworkInterfaceList.Instance.GetBestInterface();
DebugInformation.WriteLine("Finished reading network interfaces.");
// prepare PacketDispatcher, add default filters
PacketDispatcher.Create();
AddDefaultFilters();
// connect filter list to GUI
GridFilters.ItemsSource = PacketDispatcher.Instance.GetPacketFilters();
}
public void ReadPacket(EthernetPacket ethernetPacket)
{
if (ethernetPacket.Type != EthernetPacketType.Arp)
{
return;
}
var packet = (ARPPacket)ethernetPacket.PayloadPacket;
var routingTable = IPv4Router.Instance.GetRoutingTable();
if (packet.Operation == ARPOperation.Response)
{
if (!routingTable.ContainsKey(packet.SenderProtocolAddress))
{
routingTable.Add(packet.SenderProtocolAddress, ethernetPacket.SourceHwAddress);
DebugInformation.WriteLine(String.Format("[ARP] adding entry {0} - {1} to routing table",
packet.SenderProtocolAddress, ethernetPacket.SourceHwAddress));
}
}
}
