I am trying to simulate a fattree network in NS3. I have UdpServerHelper and UdpClientHelper to generate traffic between two hosts. Then I call
TraceConnectWithoutContext ("MacTx", MakeCallback (&SinkMethod))
on one of my NetDeviceContainer nodes and my SinkMethod (Ptr<const Packet> pkt) is successfully called. I can use pkt->GetSize () to see the packet size but although I took a considerable amount of time browsing for the solution, I could not figure out how I can see the source and destination addresses of the packet since the header seems to be empty.
The Headers on the Packets can either be Peek()ed or Remove()d. But, you can only the Peek() the top-most header, here a link-layer header, eg. PppHeader.
To access higher-layer headers, the preceding header must be removed first. Something along these lines should do the trick:
static void
RxDrop(Ptr<const Packet> packet) {
/*
* Need to copy packet since headers need to be removed
* to be inspected. Alternatively, remove the headers,
* and add them back.
*/
Ptr<Packet> copy = packet->Copy();
// Headers must be removed in the order they're present.
PppHeader pppHeader;
copy->RemoveHeader(pppHeader);
Ipv4Header ipHeader;
copy->RemoveHeader(ipHeader);
std::cout << "Source IP: ";
ipHeader.GetSource().Print(std::cout);
std::cout << std::endl;
std::cout << "Destination IP: ";
ipHeader.GetDestination().Print(std::cout);
std::cout << std::endl;
}