实验二IP数据包的捕获与解析

1、实验二 IP数据包的捕获与解析网络0902 1.实验目的：掌握网络层的基本原理，通过编程实现网卡截取标准格式的IP包；解析IP数据包，了解IP包结构中个字段的含义与用途。2.实验原理：IP数据报结构：3. 实验环境平台：Windows、编程环境：VC 6.0、语言：C+4流程图及源代码#include<iostream> #include<winsock2.h> #include<ws2tcpip.h> #include<fstream>#include <windows.h> #pragma comment(lib,"ws

2、2_32") /指定连接到网络应用和internet#define IO_RCVALL _WSAIOW(IOC_VENDOR,1) typedef struct IP_HEAD union /定义联合 unsigned char Version; unsigned char HeadLen; ; unsigned char ServiceType; unsigned short TotalLen; unsigned short Identifier; union unsigned short Flags; unsigned short FragOffset; ; unsigned c

3、har TimeToLive; unsigned char Protocol; unsigned short HeadChecksum; unsigned int SourceAddr; unsigned int DestinAddr; unsigned char Options; ip_head; /定义IP头部的数据结构void main(int argc,char *argv) using namespace std; ofstream outfile("C:logfile.txt",ios:out);if(argc!=2) cout<<endl<&

4、lt;"请以下格式输入命令行:PackParse packet_sum"<<endl; return; WSADATA WSAData; if(WSAStartup(MAKEWORD(2,2), &WSAData)!=0) cout<<endl<<"WSASTartup初始化失败"<<endl; return; SOCKET sock=socket(AF_INET,SOCK_RAW,IPPROTO_IP); /三个参分别为通信发生的区字段，套接字的类型，与IP协议if(sock=INVALID_SO

5、CKET) cout<<endl<<"创建Socket失败!"<<endl; closesocket(sock); WSACleanup(); BOOL flag=TRUE; if(setsockopt(sock,IPPROTO_IP,IP_HDRINCL,(char *) &flag,sizeof(flag)=SOCKET_ERROR) cout<<endl<<"setsockopt操作失败:"<<WSAGetLastError()<<endl; closeso

6、cket(sock); WSACleanup(); char hostName128;/获取主机名 if(gethostname(hostName,100)=SOCKET_ERROR) cout<<endl<<"gethostname操作失败:"<<WSAGetLastError()<<endl; closesocket(sock); WSACleanup(); hostent *pHostIP; /获取本地IPif(pHostIP=gethostbyname(hostName)=NULL) cout<<endl&

7、lt;<"gethostbyname操作失败:"<<WSAGetLastError()<<endl; closesocket(sock); WSACleanup(); sockaddr_in host_addr;/ host_addr.sin_family=AF_INET; host_addr.sin_port=htons(6000); host_addr.sin_addr=*(in_addr *)pHostIP->h_addr_list0; if(bind(sock,(PSOCKADDR)&host_addr,sizeof(ho

8、st_addr)=SOCKET_ERROR) cout<<endl<<"bind操作失败:"<<WSAGetLastError()<<endl; closesocket(sock); /绑定网卡WSACleanup(); DWORD dwBufferLen10; DWORD dwBufferInLen=1; DWORD dwBytesReturned=0; if(WSAIoctl(sock , IO_RCVALL ,&dwBufferInLen , sizeof(dwBufferInLen) , &dwBuff

9、erLen,sizeof(dwBufferLen),&dwBytesReturned,NULL,NULL)=SOCKET_ERROR) cout<<endl<<"WSAIoctl操作失败:"<<WSAGetLastError()<<endl; closesocket(sock); /将网卡设为混杂模式，以接受所有数据WSACleanup(); cout<<endl<<"开始解析IP包:"<<endl; char buffer65535; /设置缓冲区int pac

10、ksum=atoi(argv1); /字符串转换为整形for(int i=0;i<packsum;i+) if(recv(sock,buffer,65535,0)>0) /四个参数分别是套接字描述符，缓冲区的地址，缓冲区大小，附加标志 ip_head ip=*(ip_head *)buffer; cout<<"-"<<endl; cout<<"版本:"<<(ip.Version>>4)<<endl; /获取头部长度字段cout<<"头部长度:&quo

11、t;<<(ip.HeadLen &0x0f)*4)<<endl; /获取头部长度字段cout<<"服务类型:Priority"<<(ip.ServiceType>>5)<<", Service"<<(ip.ServiceType>>1)&0x0f)<<endl; /优先级子域和TOS子域cout<<"总长度:"<<ip.TotalLen<<endl;/获取总长度字段 cout&

12、lt;<"标识符:"<<ip.Identifier<<endl;/获取标识字段 cout<<"标志位:"<<(ip.Flags>>15)&0x01)<<",DF= "<<(ip.Flags>>14)&0x01)<<",Mf="<<(ip.Flags>>13)&0x01)<<endl; /获得标志字段cout<<"片偏移:&

13、quot;<<(ip.FragOffset&0x1fff)<<endl; /获取分段偏移字段cout<<"生存周期:"<<(int)ip.TimeToLive<<endl; /获取生存时间字段cout<<"协议:Protocol"<<(int)ip.Protocol<<endl; /获取协议字段cout<<"头部校验和:"<<ip.HeadChecksum<<endl; /获取头校验和字段cout

14、<<"原地址:"<<inet_ntoa(*(in_addr *)&ip.SourceAddr)<<endl; /获取源IP地址字段cout<<"目的IP地址:"<<inet_ntoa(*(in_addr *)&ip.DestinAddr)<<endl; /获取目的IP地址字段outfile<<"-"<<endl; outfile<<"版本:"<<(ip.Version>>

15、;4)<<endl; outfile<<"头部长度:"<<(ip.HeadLen &0x0f)*4)<<endl; outfile<<"服务类型:Priority"<<(ip.ServiceType>>5)<<", Service"<<(ip.ServiceType>>1)&0x0f)<<endl; outfile<<"总长度:"<<ip.Tot

16、alLen<<endl; outfile<<"标识符:"<<ip.Identifier<<endl; outfile<<"标志位:"<<(ip.Flags>>15)&0x01)<<",DF= "<<(ip.Flags>>14)&0x01)<<",Mf="<<(ip.Flags>>13)&0x01)<<endl; outfile<<"片偏移:"<<(ip.FragOffset&0x1fff)<<endl; outfile<<"生存周期:"<<(int)ip.TimeToLive<<endl; outfile<<"协议:Protocol"<<(int)ip.Protocol<<endl; outfile<<"头部校验和:"&l