How can I get the string context from a received packet?? CopyData and *packet both failed

[C.Wu]

Hello, everyone!

I am working on WSN simulations. Now I have encountered a problem with packet. In my simulation, I need to make every node send a broadcast packet to its neighbor node. In the packet, I would like to write some information into its buffer like:

stringstream pktContents("Hello");

Ptr<Packet> pkt = Create<Packet>((uint8_t *)pktContents.str().c_str(), pktContents.str().length());

and add an ipv4 header to record the destination, source and identification:

Ipv4Header ipv4Header;

ipv4Header.SetDestination(senseIfs.GetAddress(0));

ipv4Header.SetSource(sinkIf.GetAddress(0));

ipv4Header.SetIdentification(1);

pkt->AddHeader(ipv4Header);

Then, when the destination node received the packet, there is a callback to analyze the socket. In the callback, I can get the packet in the socket. But there comes the problem that I cannot access the contents("Hello") in any ways I know, such as CopyData, *packet: 

When I use *packet like:

cout<<"Contents: "<<*packet<<endl

<<"Size: "<<packet->GetSize()<<"Bytes"<<", including "<<h.GetSerializedSize()<<"Bytes "<<h.GetTypeId()<<std::endl

I get nothing:

Contents: 

Size: 5Bytes, including 20Bytes ns3::Ipv4Header

If I use CopyData, there comes an error:

ostream *os;

packet->CopyData(os, packet->GetSize ());

The error information indicates os uninitialized, I don't know how I should initialize it.

Thank you so much for your help and support.

Best wishes

Wu Chao

[Tommaso Pecorella]

Try to use this:

https://www.nsnam.org/docs/doxygen/classns3_1_1_packet.html#a5a6d304b9e0d90733919ffe224b98f0d

T.

[C.Wu]

Thanks, I've solved the problem by using ostringstream when CopyData(ostream *, uint32_t)