NS3 Ptr<Rocket> 与 TcpRocket 的一个小问题

前因：ns3网络仿真

实验进行到很关键的一步，我尝试进行了代码的编写(还没有添加Traceback的函数)，如下：

#include "ns3/core-module.h"
#include "ns3/internet-module.h"
#include "ns3/network-module.h"
#include "ns3/point-to-point-module.h"
#include "ns3/applications-module.h"
#include "ns3/netanim-module.h"
#include "ns3/csma-module.h"
#include <string>
#include <iostream>

using namespace std;
using namespace ns3;
NS_LOG_COMPONENT_DEFINE( "MyFirstNS3Project" );

int main(int argc, char *argv[])
{
	NodeContainer nodes;
	nodes.Create(2);

	PointToPointHelper p2pHelper;
	p2pHelper.SetDeviceAttribute( "DataRate",  StringValue("5Mbps") );
	p2pHelper.SetChannelAttribute( "Delay",  StringValue("2ms") );

	NetDeviceContainer devices;
	devices = p2pHelper.Install( nodes );

	//Rate Error Model
	Ptr<RateErrorModel> em = CreateObject<RateErrorModel>();
	em->SetAttribute( "ErrorRate",  DoubleValue(0.00001) );
	devices.Get(1)->SetAttribute( "RecieveErrorModel", PointerValue(em) );

	//Agreement Stack
	InternetStackHelper stack;
	stack.Install( nodes );

	//Set IP Address
	Ipv4AddressHelper addressHelper;
	addressHelper.SetBase( "10.1.1.0", "255.255.255.252" );
	Ipv4InterfaceContainer interfaces = addressHelper.Assign( devices );  //interfaces

	uint16_t sinkPort = 8080;
	Address sinkAddress( InetSocketAddress( interfaces.GetAddress(1),  sinkPort ) );

	PacketSinkHelper packetSinkHelper( "TcpSocketFactory",  InetSocketAddress( Ipv4Address::GetAny(), sinkPort ) );

	ApplicationContainer sinkApps = packetSinkHelper.Install( nodes.Get(1) );  //Set send-message-application in nodes.Get(1); port : 8080
	sinkApps.Start( Seconds(0.0) );
	sinkApps.Stop( Seconds(10.0) );

	uint32_t a = 1040, b = 1000;
	Ptr<MyApp> app = CreateObject <MyApp> ();
	Ptr<Socket> p = TcpSocket;
	DataRate d("1Mbps");
	app->Setup(p, sinkAddress, a, b, d);

	nodes.Get(0)->AddApplication(app); //Set receive-message-application in nodes.Get(0);
	app->SetStartTime( Seconds(1.0) );
	app->SetStopTime( Seconds(10.0) );

	AnimationInterface anim("MyFirstNS3Project.xml");
	Simulator::Run();
	Simulator::Destroy();

	return 0;
}

// 2016/7/13 wasdns

接下来我将它在scratch目录下改为.cc模式，正打算产生xml文件时，./waf编译错误，提示没有MyApp这个类。

好吧，那我就暂时当编译器瞎了。在原有的fifth.cc中找到了MyApp的原型，并且将它拷贝了过来。参见我的上一篇博客：MyApp

OK，类的代码添加上去了，这下总行了吧。结果在一个智能指针的地方报错，中文大意是在“,”前有一个语法错误，编译器不通过。

经过漫长时间的排查，锁定在了原文的：app->Setup (ns3::TcpSocket, sinkAddress, 1040, 1000, DataRate ("1Mbps"));之中的TcpRocket

关于Setup函数：

void
MyApp::Setup (Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate)
{
  m_socket = socket;
  m_peer = address;
  m_packetSize = packetSize;
  m_nPackets = nPackets;
  m_dataRate = dataRate;
}

关于TcpRocket：官方文档

1.首先它是由 Rocket 派生而来的。2.其次由于内含纯虚函数，无法进行实例化。3.TcpRocket是一个类的名字。

文档中传递TcpRocket类名字的方法肯定是不可取的，于是查阅了相关资料和咨询了老师以后，决定使用Socket::CreateSocket()这个函数，它返回的类型是Ptr。于是做出了如下改正：

//uint32_t a = 1040, b = 1000;
Ptr<MyApp> app = CreateObject <MyApp> ();
Ptr<Socket> ns3TcpSocket = Socket::CreateSocket(nodes.Get(0), TcpSocketFactory::GetTypeId());
app->Setup(ns3TcpSocket, sinkAddress);

在上面我也对MyApp的函数Setup进行了重构：

void Setup (Ptr<Socket>socket, Address address, uint32_t packetSize = 1040, uint32_t nPackets = 1000);

void
MyApp::Setup (Ptr<Socket>socket, Address address, uint32_t packetSize, uint32_t nPackets)
{
  DataRate dataRate("1Mbps");

  m_socket = socket;
  m_peer = address;
  m_packetSize = packetSize;
  m_nPackets = nPackets;
  m_dataRate = dataRate;
}

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