网络通信程序设计实验二路由跟踪

1、-作者xxxx-日期xxxx网络通信程序设计实验二路由跟踪【精品文档】 实 验 报 告 课程名称 网络通信程序设计 实验仪器 计算机 实验名称 路由跟踪 系 别 _计算机学院_ 专 业 _ 班级/学号_ _学生姓名 实验日期 2014年4月6日 成 绩 _ 指导教师 焦健 实验二 路由跟踪实验一、实验目的 学习分析程序功能结构。熟悉ICMP协议的工作原理和路由跟踪的原理。掌握VC6.0下程序调试、运行的基本方法。二、实验原理路由跟踪的实现就是巧妙地利用了ICMP报文的TTL超时报文。其实现过程如下：源主机先向目的主机发送一个回应请求报文（类型8），TTL值设为1，第一个路由器收到后将TTL减1

2、，这样TTL变为0，分组被废除。同时路由器向源主机发送一个TTL超时报文（类型为11），报文的IP包头中的源IP地址就是第一个路由器的地址，源主机就可以通过对该报文进行分析，得到第一个路由器的地址。接着发送TTL等于2的报文得到第二个路由器地址，再发TTL等于3的报文。如此下去直到收到目的主机的回应应答报文（类型为0）或目的不可达报文（类型为3），或者到了最大跳数(要检测路由器个数的最大值)。可以看到，对TTL的设置是实现跟踪的关键，使用函数setsockopt(m_Sock, IPPROTO_IP, IP_TTL,(LPSTR)&TTL,sizeof(int) 可以对其进行设置，m_

3、Sock是所创建的套接字，IP_TTL说明是进行TTL设置，TTL即是要设置的TTL值，为一个整形数值 。其实现流程如图1所示：图 1路由跟踪流程图三、实验内容 1、按照附录内容给RouteTrace程序添加代码，增加注释，调试程序通过。源代码：/ RouteTrace.cpp : Defines the class behaviors for the application.#include "stdafx.h"#include "RouteTrace.h"#include "RouteTraceDlg.h"#ifdef _DEBU

4、G#define new DEBUG_NEW#undef THIS_FILEstatic char THIS_FILE = _FILE_;#endif/ CRouteTraceAppBEGIN_MESSAGE_MAP(CRouteTraceApp, CWinApp)/AFX_MSG_MAP(CRouteTraceApp)/ NOTE - the ClassWizard will add and remove mapping macros here./ DO NOT EDIT what you see in these blocks of generated code!/AFX_MSGON_CO

5、MMAND(ID_HELP, CWinApp:OnHelp)END_MESSAGE_MAP()/ CRouteTraceApp constructionCRouteTraceApp:CRouteTraceApp()/ TODO: add construction code here,/ Place all significant initialization in InitInstance/ The one and only CRouteTraceApp objectCRouteTraceApp theApp;/ CRouteTraceApp initializationBOOL CRoute

6、TraceApp:InitInstance()AfxEnableControlContainer();/ Standard initialization/ If you are not using these features and wish to reduce the size/ of your final executable, you should remove from the following/ the specific initialization routines you do not need.#ifdef _AFXDLLEnable3dControls();/ Call

7、this when using MFC in a shared DLL#elseEnable3dControlsStatic();/ Call this when linking to MFC statically#endifCRouteTraceDlg dlg;m_pMainWnd = &dlg;int nResponse = dlg.DoModal();if (nResponse = IDOK) / TODO: Place code here to handle when the dialog is/ dismissed with OKelse if (nResponse = ID

8、CANCEL)/ TODO: Place code here to handle when the dialog is/ dismissed with Cancel/ Since the dialog has been closed, return FALSE so that we exit the/ application, rather than start the application's message pump.return FALSE;源代码：ICMP.cpp / ICMP.cpp: implementation of the CICMP class.#include &

9、quot;stdafx.h"#include "RouteTrace.h"#include "ICMP.h"#include "ws2tcpip.h"#ifdef _DEBUG#undef THIS_FILEstatic char THIS_FILE=_FILE_;#define new DEBUG_NEW#endif/ Construction/Destruction/CICMP:CICMP()winsock = 0;m_pIp = NULL;m_pIcmp = NULL;m_pIp = (IP_HEAD *)new BY

10、TEMAX_PACKET;m_pIcmp = (ICMP_HEAD *)new BYTEMAX_PACKET;CICMP:CICMP()delete m_pIp;delete m_pIcmp;BOOL CICMP:Initialize()WSADATA wsadata;if( WSAStartup(MAKEWORD(2, 1),&wsadata) ) AfxMessageBox("WSAStartup初始化失败!");return FALSE;winsock= WSASocket (AF_INET, /建立socket SOCK_RAW, IPPROTO_ICMP,

11、 NULL, 0,0);if(!winsock)AfxMessageBox( "Socket创建失败!");return FALSE;int timeout =5000;setsockopt(winsock,SOL_SOCKET,SO_RCVTIMEO,(char *)&timeout, /设置接收超时sizeof(timeout);timeout = 5000;setsockopt(winsock,SOL_SOCKET,SO_SNDTIMEO,(char *)&timeout, /设置发送超时sizeof(timeout);return TRUE;void

12、 CICMP:Uninitialize() /释放Socketif(winsock)closesocket(winsock);WSACleanup();USHORT CICMP:CheckSum(USHORT *buffer, int size) /计算校验和 unsigned long cksum = 0; while(size > 1) cksum+=*buffer+;size -=sizeof(USHORT); if(size ) cksum += *(UCHAR*)buffer; cksum = (cksum >> 16) + (cksum & 0xffff)

13、; cksum += (cksum >>16); return (USHORT)(cksum);BOOL CICMP:SendICMPPack(char *pAddr)sockaddr_in sockAddr;memset(void *)&sockAddr,0,sizeof(sockAddr);sockAddr.sin_family = AF_INET;sockAddr.sin_port = 0;sockAddr.sin_addr.S_un.S_addr=inet_addr(pAddr);return SendICMPPack(&sockAddr);/-设置TTL-

14、int CICMP:SetTTL(int TTL)int nRet=setsockopt(winsock, IPPROTO_IP, IP_TTL,(LPSTR)&TTL,sizeof(int); if(nRet=SOCKET_ERROR) CString ttlerr;ttlerr.Format("设置 TTL 错误!");AfxMessageBox(ttlerr);return 0;return 1;/-发送-BOOL CICMP:SendICMPPack(sockaddr_in *pAddr)/填充ICMP数据各项int state;char *p_data;m

15、_pIcmp->type = ICMP_ECHO;m_pIcmp->code = 0;m_pIcmp->ID = (USHORT)GetCurrentProcessId();m_pIcmp->number = 0;m_pIcmp->time = GetTickCount();m_pIcmp->cksum = 0;/填充数据p_data = (char *)m_pIcmp + sizeof(ICMP_HEAD);memset(char *)p_data,'0',DEF_PACKET);/检查和m_pIcmp->cksum = CheckS

16、um(USHORT *)m_pIcmp,DEF_PACKET+sizeof(ICMP_HEAD);/发送数据state = sendto(winsock,(char *)m_pIcmp,DEF_PACKET+sizeof(ICMP_HEAD),NULL,(struct sockaddr *)pAddr,sizeof(sockaddr);if(state = SOCKET_ERROR) if(GetLastError()=WSAETIMEDOUT)m_strInfo = "连接超时!(发送)"elsem_strInfo="出现未知发送错误!"return

17、FALSE;if(state <DEF_PACKET) m_strInfo = "发送数据错误!"return FALSE;memcpy(void *)&m_sockAddr,(void *)pAddr,sizeof(sockaddr_in);return TRUE;/-接收数据-BOOL CICMP:RecvICMPPack()int state;int len = sizeof(sockaddr_in);char * addr; struct hostent *lpHostent = NULL; int Maxfd = 1; / 监视的最大的文件描述符值+

18、1 fd_set readFdSet; / 设置文件描述符 struct timeval Timeout; addr = inet_ntoa(m_sockAddr.sin_addr); FD_ZERO(&readFdSet); FD_SET(winsock, &readFdSet); Maxfd = max(Maxfd, winsock) + 1; Timeout.tv_sec = 10; / 设置响应时间限制 Timeout.tv_usec = 0; int e = :select(Maxfd, &readFdSet, NULL, NULL, &Timeout

19、); /获取多路复用套接字的响应结果 if(e <= 0) routeaddr="*"routestate=1;RouteState="超时未知" return FALSE; if(!FD_ISSET(winsock, &readFdSet) return FALSE;state=recvfrom(winsock,(char*)m_pIp,MAX_PACKET,0,(struct sockaddr*)&m_sockAddr,&len);if (state = SOCKET_ERROR) if (WSAGetLastError

20、() = WSAETIMEDOUT)m_strInfo.Format("接收超时,路由跟踪失败!");routestate=0;RouteState="路由跟踪失败!"elsem_strInfo = "未知接收错误!"return FALSE;/分析数据int ipheadlen;ipheadlen = m_pIp->HeadLen * 4 ;if (state < (ipheadlen+MIN_PACKET)m_strInfo = "目的地址的响应数据不正确"return FALSE;ICMP_HEA

21、D * p_icmprev;p_icmprev = (ICMP_HEAD*)(char *)m_pIp + ipheadlen); switch (p_icmprev->type)case ICMP_ECHOREPLY: /收到正常回显m_strInfo.Format("接收到%s %d字节响应数据,响应时间:%dms.",inet_ntoa(m_sockAddr.sin_addr),len,GetTickCount()-p_icmprev->time);routeaddr=addr;routestate=0; RouteState="到达目的主机！" return TRUE;