public int Receive(out byte[] buffer)
{
// retrieve data from allocated buffer.
NetworkBufferFactory.Buffer data = _socketState.bufferFactory.GetNextAllocatedBuffer();
buffer = data?.Data;
return(data?.AllocatedSize ?? 0);
}
public void FreeBuffer(ref byte[] buffer)
{
NetworkBufferFactory.Buffer data = new NetworkBufferFactory.Buffer()
{
Data = buffer, AllocatedSize = 0
};
_socketState.bufferFactory.AddFreeBuffer(data);
}
private static void OnReceive(IAsyncResult ar)
{
try
{
SocketState state = ar.AsyncState as SocketState;
if (state == null)
{
return;
}
NetworkBufferFactory.Buffer buffer = state?.buffer;
lock (state.socketLock)
{
if (state.socket == null)
{
return;
}
int received = state.socket.EndReceive(ar);
state.buffer = state.bufferFactory.GetNextFreeBuffer();
state.socket.BeginReceive(state.buffer.Data, 0, state.buffer.Data.Length, SocketFlags.None, new System.AsyncCallback(OnReceive), (object)state);
if (received > 0)
{
buffer.AllocatedSize = received;
state.bufferFactory.AddAllocatedBuffer(buffer);
}
}
}
catch (ObjectDisposedException)
{
// do nothing - teardown occurring.
}
catch (Exception ex)
{
Trace.WriteLine("RawSocket: Error while receiving socket data. Network capture aborted, please restart application." + ex.ToString(), "DEBUG-MACHINA");
}
}
private unsafe void RunCaptureLoop()
{
bool bExceptionLogged = false;
while (_cancelThread == false)
{
try
{
if (_activeDevice == null)
{
Thread.Sleep(100);
continue;
}
IntPtr packetDataPtr = IntPtr.Zero;
IntPtr packetHeaderPtr = IntPtr.Zero;
int layer2Length = (_activeDevice.LinkType == DLT_EN10MB ? 14 : 4); // 14 for ethernet, 4 for loopback
// note: buffer returned by pcap_next_ex is static and owned by pcap library, does not need to be freed.
int status = pcap_next_ex(_activeDevice.Handle, ref packetHeaderPtr, ref packetDataPtr);
if (status == 0) // 500ms timeout
{
continue;
}
else if (status == -1) // error
{
string error = Marshal.PtrToStringAnsi(pcap_geterr(_activeDevice.Handle));
if (!bExceptionLogged)
{
Trace.WriteLine("RawPCap: Error during pcap_loop. " + error);
}
bExceptionLogged = true;
Thread.Sleep(100);
}
else if (status != 1) // anything else besides success
{
if (!bExceptionLogged)
{
Trace.WriteLine("RawPCap: Unknown response code [" + status.ToString() + "] from pcap_next_ex.);");
}
bExceptionLogged = true;
Thread.Sleep(100);
}
else
{
pcap_pkthdr packetHeader = *(pcap_pkthdr *)packetHeaderPtr;
if (packetHeader.caplen <= layer2Length)
{
continue;
}
NetworkBufferFactory.Buffer buffer = _bufferFactory.GetNextFreeBuffer();
// prepare data - skip the 14-byte ethernet header
buffer.AllocatedSize = (int)packetHeader.caplen - layer2Length;
if (buffer.AllocatedSize > buffer.Data.Length)
{
Trace.WriteLine("RawPCap: packet length too large: " + buffer.AllocatedSize.ToString());
}
else
{
Marshal.Copy(packetDataPtr + layer2Length, buffer.Data, 0, buffer.AllocatedSize);
_bufferFactory.AddAllocatedBuffer(buffer);
}
}
}
catch (ThreadAbortException)
{
// do nothing, thread is aborting.
return;
}
catch (Exception ex)
{
if (!bExceptionLogged)
{
Trace.WriteLine("WinPCap: Exception during RunCaptureLoop. " + ex.ToString());
}
bExceptionLogged = true;
// add sleep
Thread.Sleep(100);
}
}
}
