/// <summary>
/// Convert an array of keys into unmanaged memory
/// </summary>
/// <param name="value"></param>
/// <returns></returns>
private static IntPtr KeysToIntPtr(List <AirPcapKey> value)
{
// allocate memory for the entire collection
IntPtr pKeyCollection = Marshal.AllocHGlobal(AirPcapDevice.KeyCollectionSize(value.Count));
var pKeyCollectionPosition = pKeyCollection;
// build the collection struct
var collection = new AirPcapUnmanagedStructures.AirpcapKeysCollection();
collection.nKeys = (uint)value.Count;
// convert this collection to unmanaged memory
Marshal.StructureToPtr(collection, pKeyCollectionPosition, false);
// advance the pointer
pKeyCollectionPosition = new IntPtr(pKeyCollectionPosition.ToInt64() +
Marshal.SizeOf(typeof(AirPcapUnmanagedStructures.AirpcapKeysCollection)));
// write the keys to memory
for (int x = 0; x < value.Count; x++)
{
var key = new AirPcapUnmanagedStructures.AirpcapKey();
key.KeyType = value[x].Type;
key.KeyLen = (uint)value[x].Data.Length;
// make sure we have the right size byte[], the fields in the structure passed to Marshal.StructureToPtr()
// have to match the specified sizes or an exception will be thrown
key.KeyData = new byte[AirPcapUnmanagedStructures.WepKeyMaxSize];
Array.Copy(value[x].Data, key.KeyData, value[x].Data.Length);
// copy the managed memory into the unmanaged memory
Marshal.StructureToPtr(key, pKeyCollectionPosition, false);
// advance the pointer
pKeyCollectionPosition = new IntPtr(pKeyCollectionPosition.ToInt64() + Marshal.SizeOf(typeof(AirPcapUnmanagedStructures.AirpcapKey)));
}
return(pKeyCollection);
}
/// <summary>
/// Marshal a chunk of captured packets into a packet list
/// </summary>
/// <param name="packetsBuffer"></param>
/// <param name="bufferEnd"></param>
/// <param name="packets"></param>
protected virtual void MarshalPackets(IntPtr packetsBuffer, IntPtr bufferEnd,
out List <RawCapture> packets)
{
RawCapture p;
var linkType = LinkType;
packets = new List <RawCapture>();
IntPtr bufferPointer = packetsBuffer;
while (bufferPointer.ToInt64() < bufferEnd.ToInt64())
{
// marshal the header
var header = new AirPcapPacketHeader(bufferPointer);
// advance the pointer to the packet data and marshal that data
// into a managed buffer
bufferPointer = new IntPtr(bufferPointer.ToInt64() + header.Hdrlen);
var pkt_data = new byte[header.Caplen];
Marshal.Copy(bufferPointer, pkt_data, 0, (int)header.Caplen);
p = new RawCapture(linkType,
new PosixTimeval(header.TsSec,
header.TsUsec),
pkt_data);
packets.Add(p);
// advance the pointer by the size of the data
// and round up to the next word offset since each frame header is on a word boundry
int alignment = 4;
var pointer = bufferPointer.ToInt64() + header.Caplen;
pointer = AirPcapDevice.RoundUp(pointer, alignment);
bufferPointer = new IntPtr(pointer);
}
}
