// LISTENS TO VPN ADAPTER AND SENDS THE SPECIFIC PACKETS OUT THE NORMAL ADAPTER
private static void TreatOUTPacketsVPNtoNormal(NdisApiDotNet outNdisapi, NetworkAdapter vpnAdapter, NetworkAdapter normalAdapter)
{
// Lists for re-injecting packets
List <RawPacket> toAdapter = new List <RawPacket>();
List <RawPacket> toMstcp = new List <RawPacket>();
// Unmanaged memory resource for sending receiving bulk of packets
// Maximum number of packets to send/receive = 64
NdisBufferResource buffer = new NdisBufferResource(64);
outNdisapi.SetAdapterMode(vpnAdapter.Handle, MSTCP_FLAGS.MSTCP_FLAG_TUNNEL);
outNdisapi.SetPacketEvent(vpnAdapter.Handle, outPacketEvent);
do
{
outPacketEvent.WaitOne();
var packetList = outNdisapi.ReadPackets(vpnAdapter.Handle, buffer);
while (packetList.Item1)
{
foreach (var packet in packetList.Item2)
{
Packet p = null;
EthernetPacket ethernetPacket = null;
TcpPacket tcpPacket = null;
IPv4Packet ipv4Packet = null;
ushort sport = 0;
ushort dport = 0;
try {
p = Packet.ParsePacket(LinkLayers.Ethernet, packet.Data);
ethernetPacket = (EthernetPacket)p;
tcpPacket = (TcpPacket)((IPPacket)((EthernetPacket)p).PayloadPacket).PayloadPacket;
ipv4Packet = (IPv4Packet)((EthernetPacket)p).PayloadPacket;
sport = tcpPacket.SourcePort;
dport = tcpPacket.DestinationPort;
} catch (Exception ex) {
if (packet.DeviceFlags == PACKET_FLAG.PACKET_FLAG_ON_RECEIVE)
{
toMstcp.Add(packet);
}
else
{
toAdapter.Add(packet);
}
Console.WriteLine($"An exeption {ex.Message} occured while trying to parse network packet. Packet will be let thru without any changes");
continue;
}
DumpSourceChangingFilteredPacket(packet.DeviceFlags,
ipv4Packet.SourceAddress.ToString(),
sport.ToString(),
ipv4Packet.DestinationAddress.ToString(),
dport.ToString(),
p.Bytes.Length,
packet.DeviceFlags == PACKET_FLAG.PACKET_FLAG_ON_RECEIVE);
if (packet.DeviceFlags == PACKET_FLAG.PACKET_FLAG_ON_RECEIVE)
{
// Packet was received on VPN adapter, leave it as it is
toMstcp.Add(packet);
}
else
{
if (ipv4Packet.SourceAddress.Equals(vpnIP))
{
// Change the Source for outgoing packets that will later be sent thru normal adapter
ipv4Packet.SourceAddress = localIp;
ethernetPacket.SourceHardwareAddress = localMacAddress;
ipv4Packet.UpdateIPChecksum();
tcpPacket.UpdateTcpChecksum();
ethernetPacket.UpdateCalculatedValues();
var newPackage = new RawPacket()
{
Data = p.Bytes,
FilterId = packet.FilterId,
Dot1q = packet.Dot1q,
NdisFlags = packet.NdisFlags,
DeviceFlags = packet.DeviceFlags
};
toAdapter.Add(newPackage);
}
else
{
toAdapter.Add(packet);
}
}
}
if (toMstcp.Count > 0)
{
// If we have packets to forward upwards the network stack then do it here
// RECEIVED SHOULD BE TREATED BY VPN ADAPTER
outNdisapi.SendPacketsToMstcp(vpnAdapter.Handle, buffer, toMstcp);
toMstcp.Clear();
}
if (toAdapter.Count > 0)
{
// If we have packets to forward downwards the network stack then do it here
// SENT SHOULD BE TREATED BY NORMAL ADAPTER
outNdisapi.SendPacketsToAdapter(normalAdapter.Handle, buffer, toAdapter);
toAdapter.Clear();
}
packetList = outNdisapi.ReadPackets(vpnAdapter.Handle, buffer);
}
;
outPacketEvent.Reset();
} while (!stopCapturing);
//
// Release driver and associated resources
//
buffer.Dispose();
outNdisapi.SetPacketEvent(vpnAdapter.Handle, null);
outNdisapi.SetAdapterMode(vpnAdapter.Handle, 0);
}
/// <summary>
/// 実行する
/// </summary>
public List <ScanResponse> Execute()
{
var ret = new List <ScanResponse>();
// デバイス変換
var device = _captureDevice as NpcapDevice;
if (device == null)
{
throw new InvalidCastException(string.Format("デバイス {0} を NpcapDevice に変換できません", device.Description));
}
// 送信元IPアドレス
var srcIPAddress = GetIPv4(device);
// SYNスキャン
foreach (var request in _scanRequests)
{
// 送信先MACアドレス
var arp = new ARP(device);
var targetMacAddress = arp.Resolve(request.IPAddress);
if (targetMacAddress == null)
{
ret.Add(new ScanResponse()
{
IPAddress = request.IPAddress,
Port = request.Port,
Status = PortStatus.UnResolved
});
continue;
//throw new InvalidOperationException(string.Format("アドレス {0} を ARP 解決できません", request.IPAddress.ToString()));
}
// TCPヘッダ生成
var tcpPacket = new TcpPacket(1024, request.Port);
tcpPacket.Synchronize = !tcpPacket.Synchronize;
tcpPacket.WindowSize = 4096;
// IPヘッダ生成
var ipPacket = new IPv4Packet(srcIPAddress, request.IPAddress);
// Ehternetヘッダ生成
var ethernetPacket = new EthernetPacket(device.Interface.MacAddress, targetMacAddress, EthernetType.None);
// TCPパケット生成
ipPacket.PayloadPacket = tcpPacket;
tcpPacket.UpdateTcpChecksum();
ethernetPacket.PayloadPacket = ipPacket;
ipPacket.UpdateIPChecksum();
for (int retryCount = 0; retryCount < _maxRetryCount; retryCount++)
{
// オープン
device.Open(DeviceMode.Normal, 1000);
// フィルタセット
device.Filter = "src host " + request.IPAddress + " and src port " + request.Port + " and (tcp[13] & 18 != 0) or (tcp[13] & 4 != 0)";
try
{
// TCPパケット送信
device.SendPacket(ethernetPacket);
// 受信パケット取得
var rawpacket = device.GetNextPacket();
if (rawpacket == null)
{
if ((retryCount + 1) >= _maxRetryCount)
{
ret.Add(new ScanResponse()
{
IPAddress = request.IPAddress,
Port = request.Port,
Status = PortStatus.Timeout
});
break;
}
continue;
}
else
{
// SYN/ACKフラグが立っていたら、open判定
// RSTフラグが立っていたらclosed判定
var response = Packet.ParsePacket(rawpacket.LinkLayerType, rawpacket.Data);
if (response is EthernetPacket eth)
{
var ip = response.Extract <IPPacket>();
if (ip != null)
{
var tcp = response.Extract <TcpPacket>();
if (tcp != null)
{
if (tcp.Acknowledgment && tcp.Synchronize)
{
ret.Add(new ScanResponse()
{
IPAddress = request.IPAddress,
Port = request.Port,
Status = PortStatus.Open
});
}
else if (tcp.Reset)
{
ret.Add(new ScanResponse()
{
IPAddress = request.IPAddress,
Port = request.Port,
Status = PortStatus.Closed
});
}
else
{
ret.Add(new ScanResponse()
{
IPAddress = request.IPAddress,
Port = request.Port,
Status = PortStatus.UnKnown
});
}
}
}
}
break;
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
finally
{
if (device.Opened)
{
device.Close();
}
}
}
}
return(ret);
}
