private void OnReceive(IAsyncResult ar)
{
AsyncCaptureState so = (AsyncCaptureState)ar.AsyncState;
Socket mainSocket = so.workSocket;
try {
int nReceived = mainSocket.EndReceive(ar);
//Analyze the bytes received...
ParseData(byteData, nReceived);
if (bContinueCapturing)
{
byteData = new byte[MAX_PACKET_SIZE];
//Another call to BeginReceive so that we continue to receive the incoming
//packets
mainSocket.BeginReceive(byteData, 0, byteData.Length, SocketFlags.None,
new AsyncCallback(OnReceive), so);
}
}
catch (ObjectDisposedException)
{
}
//catch (Exception ex)
//{
// // do something with error..
// // MessageBox.Show(ex.Message, "MJsniffer", MessageBoxButtons.OK, MessageBoxIcon.Error);
// PacketEvent("ONReceive Error: " + ex.ToString());
//}
}
public void StartCapture()
{
// try
// {
if (!bContinueCapturing)
{
bContinueCapturing = true;
// start listening on every interface... so we don't have to ask the user to choose
// TODO: make a settings dialog to choose ANY or a specific interface?
IPHostEntry hostEntry = Dns.GetHostEntry((Dns.GetHostName()));
foreach (IPAddress ip in hostEntry.AddressList) {
string interfaceName = ip.ToString();
//For sniffing the socket to capture the packets has to be a raw socket, with the
//address family being of type internetwork, and protocol being IP
AddressFamily addressFamily = ip.AddressFamily;
ProtocolType protocolType;
SocketOptionLevel socketOptionLevel;
switch (ip.AddressFamily) {
case AddressFamily.InterNetwork:
protocolType = ProtocolType.IP;
socketOptionLevel = SocketOptionLevel.IP;
break;
case AddressFamily.InterNetworkV6:
protocolType = ProtocolType.IPv6;
socketOptionLevel = SocketOptionLevel.IPv6;
break;
default:
continue;
}
Socket mainSocket = new Socket(addressFamily, SocketType.Raw, protocolType);
this.listenSockets.Add(mainSocket); // it to our list of listen sockets...
//Bind the socket to the selected IP address
mainSocket.Bind(new IPEndPoint(IPAddress.Parse(interfaceName), 0));
//Set the socket options
mainSocket.SetSocketOption(socketOptionLevel, //Applies only to IP packets
SocketOptionName.HeaderIncluded, //Set the include the header
true); //option to true
byte[] byTrue = new byte[4] { 1, 0, 0, 0 };
byte[] byOut = new byte[4] { 1, 0, 0, 0 }; //Capture outgoing packets
//Socket.IOControl is analogous to the WSAIoctl method of Winsock 2
mainSocket.IOControl(IOControlCode.ReceiveAll, //Equivalent to SIO_RCVALL constant
//of Winsock 2
byTrue,
byOut);
//Start receiving the packets asynchronously
var aState = new AsyncCaptureState(mainSocket);
mainSocket.BeginReceive(byteData, 0, byteData.Length, SocketFlags.None,
new AsyncCallback(OnReceive), aState);
}
}
//} catch (Exception ex) {
// // something bad happened we should probably fix
// if (PacketEvent != null) PacketEvent("Error opening socket for packet sniffing");
//}
}
