NS-3 Socket to connect to external program - c++

Question

I am trying for a way to write a socket class to connect my NS-3 simulation to an outside program. So what I want to do is to create packets in NS-3 and send them through this socket to an outside tool, do some simple manipulations on the packet in that tool, and then send it back to NS-3. I don't think the built in NS-3 socket can be used for this purpose.
Has anyone come across something like this before or has any suggestions?
Your help is very much appreciated!

Answer 1

I'm using a TCP socket to connect an external Python TCP Socket using NS-3, here is the code:
/*
* Create a NS-3 Application that opens a TCP Socket and
* waits for incoming connections
*
*/
#include "ns3/icmpv4.h"
#include "ns3/assert.h"
#include "ns3/log.h"
#include "ns3/ipv4-address.h"
#include "ns3/socket.h"
#include "ns3/integer.h"
#include "ns3/boolean.h"
#include "ns3/inet-socket-address.h"
#include "ns3/packet.h"
#include "ns3/trace-source-accessor.h"
#include "ns3/config.h"
#include "ns3/tos-device.h"
#include "ns3/names.h"
#include "ns3/string.h"
#include "ns3/object.h"
namespace ns3 {
IOProxyServer::IOProxyServer ()
{
m_socket = 0;
}
TypeId IOProxyServer::GetTypeId (void)
{
static TypeId tid = TypeId ("ns3::IoProxyServer")
.SetParent<Application> ()
.AddConstructor<IOProxyServer> ()
.AddAttribute("RemotePortNumber",
"Remote port listening for connections",
IntegerValue(9999),
MakeIntegerAccessor(&IOProxyServer::m_remotePortNumber),
MakeIntegerChecker<int64_t>())
.AddAttribute("RemoteIp",
"Remote IP listening for connections",
StringValue("127.0.0.1"),
MakeStringAccessor(&IOProxyServer::m_remoteIp),
MakeStringChecker())
.AddAttribute("LocalPortNumber",
"Local port for incoming connections",
IntegerValue(3333),
MakeIntegerAccessor(&IOProxyServer::m_localPortNumber),
MakeIntegerChecker<int64_t>())
.AddAttribute("LocalIp",
"Local IP for incoming connections",
StringValue("127.0.0.1"),
MakeStringAccessor(&IOProxyServer::m_localIp),
MakeStringChecker());
return tid;
}
void IOProxyServer::StartApplication (void)
{
NS_LOG_FUNCTION (this);
m_socket = Socket::CreateSocket (GetNode (), TypeId::LookupByName ("ns3::TcpSocketFactory"));
NS_ASSERT_MSG (m_socket != 0, "An error has happened when trying to create the socket");
InetSocketAddress src = InetSocketAddress (Ipv4Address::GetAny(), m_localPortNumber );
InetSocketAddress dest = InetSocketAddress(Ipv4Address(m_remoteIp.c_str()), m_remotePortNumber);
int status;
status = m_socket->Bind (src);
NS_ASSERT_MSG (status != -1, "An error has happened when trying to bind to local end point");
status = m_socket->Connect(dest);
NS_ASSERT_MSG (status != -1, "An error has happened when trying to connect to remote end point");
// Configures the callbacks for the different events related with the connection
//m_socket->SetConnectCallback
m_socket->SetAcceptCallback (
MakeNullCallback<bool, Ptr<Socket>, const Address &> (),
MakeCallback (&IOProxyServer::HandleAccept, this));
m_socket->SetRecvCallback (
MakeCallback (&IOProxyServer::HandleRead, this));
m_socket->SetDataSentCallback (
MakeCallback (&IOProxyServer::HandleSend,this));
//m_socket->SetSendCallback
m_socket->SetCloseCallbacks (
MakeCallback (&IOProxyServer::HandlePeerClose, this),
MakeCallback (&IOProxyServer::HandlePeerError, this));
// If we need to configure a reception only socket or a sending only socket
// we need to call one of the following methods:
// m_socket->ShutdownSend();
// m_socket->ShutdownRecv();
}
void IOProxyServer::StopApplication (void)
{
NS_LOG_FUNCTION (this);
m_socket->Close();
}
void IOProxyServer::HandlePeerClose (Ptr<Socket> socket)
{
NS_LOG_FUNCTION (this << socket);
}
void IOProxyServer::HandlePeerError (Ptr<Socket> socket)
{
NS_LOG_FUNCTION (this << socket);
}
void IOProxyServer::HandleSend (Ptr<Socket> socket, uint32_t dataSent)
{
NS_LOG_FUNCTION (this << socket);
}
void IOProxyServer::HandleAccept (Ptr<Socket> s, const Address& from)
{
NS_LOG_FUNCTION (this << s << from);
s->SetRecvCallback (MakeCallback (&IOProxyServer::HandleRead, this));
}
void IOProxyServer::HandleRead (Ptr<Socket> socket)
{
NS_LOG_FUNCTION (this << socket);
Ptr<Packet> packet;
while ((packet = socket->RecvFrom (from)))
{
if (packet->GetSize () == 0)
{ //EOF
break;
}
if (InetSocketAddress::IsMatchingType (from))
{
//Do whatever you need with the incoming info
}
}
}
void IOProxyServer::SendData()
{
//Do whatever you need for creating your packet and send it using the socket
//Ptr<Packet> packet = Create<Packet>(pointer, sizeof(pointer));
//m_socket->Send(packet, 0, from);
}
IOProxyServer::~IOProxyServer ()
{
}
void IOProxyServer::DoDispose (void)
{
NS_LOG_FUNCTION (this);
m_socket = 0;
Application::DoDispose ();
}
} // namespace ns3