public (LinkLayerType linkLayer, byte[] data) GetPacket(int index)
{
if (_offsetsList == null || _offsetsList.Count <= index)
{
_offsetsList = _pcapngWeakHandle.GetPacketsOffsets();
}
EnhancedPacketBlock pkt = _pcapngWeakHandle.GetPacketAt(_offsetsList[index]);
var ifaces = _pcapngWeakHandle.GetInterfaces();
InterfaceDescriptionBlock iface = null;
try
{
iface = ifaces.ElementAt(pkt.AssociatedInterfaceID.Value);
}
catch (Exception ex)
{
Debug.WriteLine("Issues when " + ex);
}
return((LinkLayerType)iface.LinkType, pkt.Data);
}
private string DoExportBasedOfFile(PcapngWeakHandle basePcapngFile, IEnumerable <TempPacketSaveData> packets)
{
if (!packets.Any())
{
// No packets, just return the pack of the pcapng file
return(basePcapngFile.Path);
}
// Some packets defined, need to create modified version of the file
string tempFile = Path.ChangeExtension(Path.GetTempFileName(), "pcapng");
File.Copy(basePcapngFile.Path, tempFile);
PcapngWeakHandle tempHandle = new PcapngWeakHandle(tempFile);
var offsets = tempHandle.GetPacketsOffsets();
var ifaces = tempHandle.GetInterfaces();
foreach (TempPacketSaveData packet in packets)
{
long packetOffset = offsets[packet.PacketNumber];
EnhancedPacketBlock replacedEpb = tempHandle.GetPacketAt(packetOffset);
InterfaceDescriptionBlock interfaceOfReplacedPacket = ifaces[replacedEpb.InterfaceID];
// TODO: Sooooo I'm having some issues here because I didn't carry the interface ID into the 'TempPacketSaveData' object
// nor did I allow the user to set which interface he wants to associate the packet to.
// I'm resorting to 2 heuristics:
// 1. If the Link Layer of the exported packet looks like the one of the replaced packet, use the replaced packet's iface ID
// 2. Otherwise, look for the first interface with the new link layer
// 3. Otheriwse - NOT IMPLEMENTED, will crash. (TODO: That's where we need to inject new interfaces descirption blocks...)
int ifacedId = -1;
if (interfaceOfReplacedPacket.LinkType == (LinkTypes)packet.LinkLayer)
{
ifacedId = replacedEpb.InterfaceID;
}
else
{
for (int i = 0; i < ifaces.Count; i++)
{
if (ifaces[i].LinkType == (LinkTypes)packet.LinkLayer)
{
ifacedId = i;
}
}
if (ifacedId == -1)
{
throw new ArgumentException(
$"Couldn't find an interface in the PCAPNG for the requested link layer of the exported packet. Link Layer: {packet.LinkLayer}");
}
}
EnhancedPacketBlock epb = new EnhancedPacketBlock(ifacedId,
replacedEpb.Timestamp,
packet.Data.Length,
packet.Data,
new EnhancedPacketOption()
);
tempHandle.ReplacePacket(packetOffset, epb);
}
return(tempFile);
}
