NS3 的 ipv4-static-routing-test-suite 源码分析

下面进行源码注释：

// End-to-end tests for Ipv4 static routing

#include "ns3/boolean.h"
#include "ns3/config.h"
#include "ns3/inet-socket-address.h"
#include "ns3/internet-stack-helper.h"
#include "ns3/ipv4-address-helper.h"
#include "ns3/ipv4-static-routing-helper.h"
#include "ns3/node.h"
#include "ns3/node-container.h"
#include "ns3/packet.h"
#include "ns3/pointer.h"
#include "ns3/simulator.h"
#include "ns3/string.h"
#include "ns3/test.h"
#include "ns3/uinteger.h"
#include "ns3/simple-net-device.h"
#include "ns3/simple-channel.h"
#include "ns3/simple-net-device-helper.h"
#include "ns3/socket-factory.h"
#include "ns3/udp-socket-factory.h"

using namespace ns3;

/**
 * \ingroup internet-test
 * \ingroup tests
 *
 * \brief IPv4 StaticRouting /32 Test
 */
class Ipv4StaticRoutingSlash32TestCase : public TestCase
{
public:
  Ipv4StaticRoutingSlash32TestCase ();
  virtual ~Ipv4StaticRoutingSlash32TestCase ();

  Ptr<Packet> m_receivedPacket; //!< Received packet

  /**
   * \brief Send data.
   * \param socket The sending socket.
   * \param to Destination address.
   */
  void DoSendData (Ptr<Socket> socket, std::string to);
  /**
   * \brief Send data.
   * \param socket The sending socket.
   * \param to Destination address.
   */
  void SendData (Ptr<Socket> socket, std::string to);

  /**
   * \brief Receive data.
   * \param socket The receiving socket.
   */
  void ReceivePkt (Ptr<Socket> socket);

private:
  virtual void DoRun (void);
};

// Add some help text to this case to describe what it is intended to test
Ipv4StaticRoutingSlash32TestCase::Ipv4StaticRoutingSlash32TestCase ()
  : TestCase ("Slash 32 static routing example")
{
}

Ipv4StaticRoutingSlash32TestCase::~Ipv4StaticRoutingSlash32TestCase ()
{
}

void
Ipv4StaticRoutingSlash32TestCase::ReceivePkt (Ptr<Socket> socket)
{
  uint32_t availableData;
  availableData = socket->GetRxAvailable ();
  m_receivedPacket = socket->Recv (std::numeric_limits<uint32_t>::max (), 0);
  NS_ASSERT (availableData == m_receivedPacket->GetSize ());
  //cast availableData to void, to suppress 'availableData' set but not used
  //compiler warning
  (void) availableData;
}

void
Ipv4StaticRoutingSlash32TestCase::DoSendData (Ptr<Socket> socket, std::string to)
{
  Address realTo = InetSocketAddress (Ipv4Address (to.c_str ()), 1234);
  NS_TEST_EXPECT_MSG_EQ (socket->SendTo (Create<Packet> (123), 0, realTo),
                         123, "100");
}

void
Ipv4StaticRoutingSlash32TestCase::SendData (Ptr<Socket> socket, std::string to)
{
  m_receivedPacket = Create<Packet> ();
  Simulator::ScheduleWithContext (socket->GetNode ()->GetId (), Seconds (60),
                                  &Ipv4StaticRoutingSlash32TestCase::DoSendData, this, socket, to);
  Simulator::Stop (Seconds (66));
  Simulator::Run ();
}

// Test program for this 3-router scenario, using static routing
//
// (a.a.a.a/32)A<--x.x.x.0/30-->B<--y.y.y.0/30-->C(c.c.c.c/32)
//
void
Ipv4StaticRoutingSlash32TestCase::DoRun (void)
{

  //这里创建三个节点
  Ptr<Node> nA = CreateObject<Node> ();
  Ptr<Node> nB = CreateObject<Node> ();
  Ptr<Node> nC = CreateObject<Node> ();

  // 安装协议栈
  NodeContainer c = NodeContainer (nA, nB, nC);
  InternetStackHelper internet;
  internet.Install (c);

  // 创建了2个链接
  // a-------------b----------------c
  // |1.1     1.2  | 1.5        1.6 |
  // 172.116.1.1/24                 192.168.1.1/24
  NodeContainer nAnB = NodeContainer (nA, nB);
  NodeContainer nBnC = NodeContainer (nB, nC);

  
  
  // 路由器A添加一个接入的网卡
  Ptr<SimpleNetDevice> deviceA = CreateObject<SimpleNetDevice> ();
  deviceA->SetAddress (Mac48Address::Allocate ());
  nA->AddDevice (deviceA);

  // 路由器C添加一个接入网卡
  Ptr<SimpleNetDevice> deviceC = CreateObject<SimpleNetDevice> ();
  deviceC->SetAddress (Mac48Address::Allocate ());
  nC->AddDevice (deviceC);

  // 对AB和BC链路分别添加一个网间网的互联网卡
  SimpleNetDeviceHelper devHelper;
  NetDeviceContainer dAdB = devHelper.Install (nAnB);
  NetDeviceContainer dBdC = devHelper.Install (nBnC);

  // AB链路网间网地址
  Ipv4AddressHelper ipv4;
  ipv4.SetBase ("10.1.1.0", "255.255.255.252");
  Ipv4InterfaceContainer iAiB = ipv4.Assign (dAdB);

  // BC链路的网间网地址
  ipv4.SetBase ("10.1.1.4", "255.255.255.252");
  Ipv4InterfaceContainer iBiC = ipv4.Assign (dBdC);

  // 这里为3个路由器分别建立1个路由表，所有后面没有安装的函数，
  Ptr<Ipv4> ipv4A = nA->GetObject<Ipv4> ();
  Ptr<Ipv4> ipv4B = nB->GetObject<Ipv4> ();
  Ptr<Ipv4> ipv4C = nC->GetObject<Ipv4> ();

  // 路由表A中添加了一个接口，返回了接口的索引
  int32_t ifIndexA = ipv4A->AddInterface (deviceA);
  
  Ipv4InterfaceAddress ifInAddrA = Ipv4InterfaceAddress (Ipv4Address ("172.16.1.1"), Ipv4Mask ("/32"));
  ipv4A->AddAddress (ifIndexA, ifInAddrA);   // 路由表内，将接口和地址绑为一项
  ipv4A->SetMetric (ifIndexA, 1);            // 到该端口是几跳
  ipv4A->SetUp (ifIndexA);                   // 将端口设置为UP状态

  // 路由表C中添加了一个接口，返回了接口的索引
  int32_t ifIndexC = ipv4C->AddInterface (deviceC);
  Ipv4InterfaceAddress ifInAddrC = Ipv4InterfaceAddress (Ipv4Address ("192.168.1.1"), Ipv4Mask ("/32"));
  ipv4C->AddAddress (ifIndexC, ifInAddrC);
  ipv4C->SetMetric (ifIndexC, 1);
  ipv4C->SetUp (ifIndexC);
 
  // 静态路由
  Ipv4StaticRoutingHelper ipv4RoutingHelper;
  // 从A到C
  Ptr<Ipv4StaticRouting> staticRoutingA = ipv4RoutingHelper.GetStaticRouting (ipv4A);
  // The ifIndex 是 1; the first p2p link added
  // 到C的接入网段地址，需要发送到P2P的AB网间网的B口！！
  staticRoutingA->AddHostRouteTo (Ipv4Address ("192.168.1.1"), Ipv4Address ("10.1.1.2"), 1);

  // 同样需要在路由器B上设置相关路由
  Ptr<Ipv4StaticRouting> staticRoutingB = ipv4RoutingHelper.GetStaticRouting (ipv4B);
  // The ifIndex on 路由器 B 是 2; 0 是 loopback地址,  1 是AB链路的接口
  // 到C的接入网段地址，需要发送到P2P的BC网间网的C口！！
  staticRoutingB->AddHostRouteTo (Ipv4Address ("192.168.1.1"), Ipv4Address ("10.1.1.6"), 2);

  // 创建发送UDP数据包的测试
  Ptr<SocketFactory> rxSocketFactory = nC->GetObject<UdpSocketFactory> ();
  Ptr<Socket> rxSocket = rxSocketFactory->CreateSocket ();
  NS_TEST_EXPECT_MSG_EQ (rxSocket->Bind (InetSocketAddress (Ipv4Address ("192.168.1.1"), 1234)), 0, "trivial");
  rxSocket->SetRecvCallback (MakeCallback (&Ipv4StaticRoutingSlash32TestCase::ReceivePkt, this));

  Ptr<SocketFactory> txSocketFactory = nA->GetObject<UdpSocketFactory> ();
  Ptr<Socket> txSocket = txSocketFactory->CreateSocket ();
  txSocket->SetAllowBroadcast (true);

  // ------ Now the tests ------------

  // Unicast test
  SendData (txSocket, "192.168.1.1");
  NS_TEST_EXPECT_MSG_EQ (m_receivedPacket->GetSize (), 123, "Static routing with /32 did not deliver all packets.");

  Simulator::Destroy ();
}

/**
 * \ingroup internet-test
 * \ingroup tests
 *
 * \brief IPv4 StaticRouting /32 TestSuite
 */
class Ipv4StaticRoutingTestSuite : public TestSuite
{
public:
  Ipv4StaticRoutingTestSuite ();
};

Ipv4StaticRoutingTestSuite::Ipv4StaticRoutingTestSuite ()
  : TestSuite ("ipv4-static-routing", UNIT)
{
  AddTestCase (new Ipv4StaticRoutingSlash32TestCase, TestCase::QUICK);
}

static Ipv4StaticRoutingTestSuite ipv4StaticRoutingTestSuite; //!< Static variable for test initialization