[ndnSIM] OnData function.

[ioannoa at scss.tcd.ie]

Hello everyone,

I was looking once again at the OnData function which handles a Content
Object at each node and I was a bit confused with its code.

It has a pitEntry == 0 and in that case it has to implement a caching
action as well as a distinction between finding the content request in Pit
or not. e.g.


if (pitEntry == 0)
  {
    bool cached = false;

    if (m_cacheUnsolicitedData || (m_cacheUnsolicitedDataFromApps &&
(inFace->GetFlags () | Face::APPLICATION)))
    {
        FwHopCountTag hopCountTag;

        Ptr<Packet> payloadCopy = payload->Copy ();
        payloadCopy->RemovePacketTag (hopCountTag);

        // Optimistically add or update entry in the content store
        cached = m_contentStore->Add (header, payloadCopy, ,
header->GetTimeSinceBirth());//(+)
        if (cached == true)//(+)
            std::cout << "I've cached packet# " << origPacket->GetUid() <<
" on Node# " << node->GetId() << std::endl;//(+)
        else
            std::cout << "I haven't cached packet# " <<
origPacket->GetUid() << " on Node# " << node->GetId() <<
std::endl;//(+)
    }
    else
    {
        // Drop data packet if PIT entry is not found
        // (unsolicited data packets should not "poison" content store)

        //drop dulicated or not requested data packet
        m_dropData (header, payload, inFace);
    }

    DidReceiveUnsolicitedData (inFace, header, payload, origPacket, cached);
    return;
  }
  else
........


But, my question is why so since if pitEntry is 0 it means the specific
Content Object has not been requested, hence the Content Object should be
dropped anyway. Could someone please help me understand why?

Kind regards,
Andriana.