ping程序设计和文件传输协议的简单设计

//PING.C #include <stdio.h> #include <stdlib.h> #include <Winsock.h> #include "Ping.h" #include <string.h> //函数声明 void Ping(LPCSTR pstrHost,int n); void ReportError(LPCSTR pstrFrom);//处理错误 int WaitForEchoReply(SOCKET s); u_short in_cksum(u_short *addr,int len); //ICMP回送请求和应答函数声明 int SendEchoRequest(SOCKET,LPSOCKADDR_IN);//发送报文请求 DWORD RecvEchoReply(SOCKET,LPSOCKADDR_IN,u_char*);//接受报文信息 /////////////////////////////////////////////////// //主程序 void main(int argc,char**argv) { WSADATA wsaData; WORD wVersionRequested=MAKEWORD(1,1); /////套接字版本号 int nRet; int n; //命令行参数检查 if(argc!=3) { fprintf(stderr,"\nUsage:ping hostname n \n"); return; } //初始化Winsock nRet=WSAStartup(wVersionRequested,&wsaData); if(nRet) { fprintf(stderr,"\nError initializing Winsock\n"); return; } //Winsock版本检查 if(wsaData.wVersion!=wVersionRequested) { fprintf(stderr,"\nWinsock version not supported\n"); return; } //调用PING函数 n=atoi(argv[1]); Ping(argv[2],n); //释放Winsock WSACleanup(); } ////////////////////////////////////////////// //Ping()函数 //调用SendEchoRequest()和RecvEchoReply()函数 //并输出结果 void Ping(LPCSTR pstrHost,int n) { SOCKET rawSocket; LPHOSTENT IpHost; struct sockaddr_in saDest; struct sockaddr_in saSrc; DWORD dwTimeSent; DWORD dwElapsed; u_char cTTL; int nLoop; int nRet; int sensum=0; int recvsum=0; DWORD max=0,min=888888,sum=0; static ECHOREPLY echoReply; static ECHOREQUEST echoReq; //创建一个原始套接口 rawSocket=socket(AF_INET,SOCK_RAW,IPPROTO_ICMP); if(rawSocket==SOCKET_ERROR) { ReportError("socket()"); return ; } //根据主机名查询主机地址 IpHost=gethostbyname(pstrHost); if(IpHost==NULL) { fprintf(stderr,"\nTimeout:%s\n",pstrHost); return; } //设置目标套接口地址 saDest.sin_addr.s_addr=*((u_long FAR*)(IpHost->h_addr)); saDest.sin_family=AF_INET; saDest.sin_port=0; //输出Ping程序的提示信息，例如进行本机Ping时，输出： //Pinging localhost【127.0.0.1】with 32 bytes of data: printf("\nPinging %s[%s]with %d bytes of data:\n", pstrHost, inet_ntoa(saDest.sin_addr), REQ_DATASIZE); /*回送数据长度*/ //控制ping执行的次数p for(nLoop=0;nLoop<n;nLoop++) { //发送ICMP回送请求 SendEchoRequest(rawSocket,&saDest); nRet=sendto(rawSocket,(LPSTR)&echoReq,sizeof(ECHOREQUEST),0,(struct sockaddr *)&saDest,sizeof(saDest)); if(nRet==SOCKET_ERROR) ReportError("sento()"); else sensum=sensum+1; //使用select()等待接收回送的数据 nRet=WaitForEchoReply(rawSocket); if(nRet==SOCKET_ERROR) { ReportError("select()"); break; } if(!nRet) { printf("\nTimeOut");//输出超时提示 break; } //接收应答 dwTimeSent=RecvEchoReply(rawSocket,&saSrc,&cTTL); //计算传输时间，并输出提示信息。如： //Reply from：127.0.0.1：bytes=32 time=0ms TTL=128 dwElapsed=GetTickCount()-dwTimeSent; if(max<dwElapsed) max=dwElapsed; if(min>dwElapsed) min=dwElapsed; sum+=dwElapsed; printf("\nReply from:%s；bytes=%d time=%ldms TTL=%d", inet_ntoa(saSrc.sin_addr), REQ_DATASIZE, dwElapsed, cTTL); recvsum++; } int avg=(sensum-recvsum)/sensum*100; DWORD Average=sum/n; printf("\n"); printf("\n"); printf("ping statistics for %s:",inet_ntoa(saSrc.sin_addr)); printf("\n Packets:Sent = %d, Recvived = %d, Lost = %d ,<%d%% loss>",sensum,recvsum,sensum-recvsum,avg); printf("\nApproximate round trip times in milli_seconds:"); printf("\n minimum = %ldms, maximum = %ldms, Average = %ldms",min,max,Average); printf("\n"); nRet=closesocket(rawSocket); if(nRet==SOCKET_ERROR) ReportError("closesocket()"); } ////////////////////////////////////////////////////// //SendEchoRequst() //给目标站点发送回送请求 int SendEchoRequest(SOCKET s,LPSOCKADDR_IN lpstToAddr) { static ECHOREQUEST echoReq; static nId=1; static nSeq=1; int nRet; //填写回送请求信息 echoReq.icmpHdr.Type=ICMP_ECHOREQ; echoReq.icmpHdr.Code=0; echoReq.icmpHdr.Checksum=0; echoReq.icmpHdr.ID=nId++; echoReq.icmpHdr.Seq=nSeq++; //填写要发送的数据 for(nRet=0;nRet<REQ_DATASIZE;nRet++) echoReq.cData[nRet]=' '+nRet; //保存发送时间 echoReq.dwTime=GetTickCount(); //数据存入包中并计算校验和 echoReq.icmpHdr.Checksum=in_cksum((u_short*)&echoReq,sizeof(ECHOREQUEST)); //发送回送请求 nRet=sendto(s,(LPSTR)&echoReq,sizeof(ECHOREQUEST),0,(LPSOCKADDR)lpstToAddr,sizeof(SOCKADDR_IN)); if(nRet==SOCKET_ERROR) ReportError("sento()"); return (nRet); } ////////////////////////////////////////////////////////// //RecvechoReply() //接收数据并对字段进行分析 DWORD RecvEchoReply(SOCKET s,LPSOCKADDR_IN lpsaFrom,u_char *pTTL) { ECHOREPLY echoReply; int nRet; int nAddrLen=sizeof(struct sockaddr_in); //接收回送应答 nRet=recvfrom(s,(LPSTR)&echoReply,sizeof(ECHOREPLY),0,(LPSOCKADDR)lpsaFrom,&nAddrLen); //检查返回的值 if(nRet==SOCKET_ERROR) ReportError("recvfrom()"); //返回发送时间的IP生存时间TTL *pTTL=echoReply.ipHdr.TTL; return (echoReply.echoRequest.dwTime); } ////////////////////////////////////////////////////////// //ReportError() //输出发生的错误 void ReportError(LPCSTR pWhere) { fprintf(stderr,"\n%s error:%d\n",WSAGetLastError()); } //////////////////////////////////////////////////////// //WaitForEchoReply() //使用select()函数进行状态查询，以确定是否有数据等待读取 int WaitForEchoReply(SOCKET s) { struct timeval Timeout; fd_set readfds; readfds.fd_count=1; readfds.fd_array[0]=s; Timeout.tv_sec=5; Timeout.tv_usec=0; return (select(1,&readfds,NULL,NULL,&Timeout)); } //////////////////////////////////////////////////////// //in_cksum() //计算校验和 u_short in_cksum(u_short *addr,int len) { register int nleft=len; register u_short *w=addr; register u_short answer; register int sum=0; while(nleft>1) { sum+=*w++; nleft-=2; } if(nleft==1) { u_short u=0; *(u_char *)(&u)=*(u_char *)w; sum+=u; } sum=(sum>>16)+(sum&0xffff); sum+=(sum>>16); answer=~sum; return(answer); }