PAGE4PAGE3課程設計課程名稱《計算機網絡課程設計》題目名稱____PING程序設計____學生學院____自動化學院____專業班級_________學號學生姓名_____________指導教師_____________2009年12月30日摘要本說明書主要包括了ping程序設計的設計目的、ping程序的工作原理以及設計方案，重點介紹了ping程序的源代碼，并且附帶了實驗結果以及總結等。關鍵字：ping程序設計目錄TOC\o"1-6"\h\z\u1實驗設計目的及要求 31.1 設計目的 31.2 設計要求 32 實驗內容 32.1 定義數據結構 32.2 程序實現 32.3 程序要求 33 ping工作原理及設計方案 33.1 設計思路 33.2 設計方案 43.3 ping源程序 44 實驗結果 75 總結 76 參考文獻 7len);voidsend_packet(void);voidrecv_packet(void);intmain(intargc,CHAR*argv[]){ structhostent*host; structprotoent*protocol; inttimeout=1000; intSEND_COUNT=4; inti; char*par_host; charm_Input[100]; printf("InputIP:"); gets(m_Input); par_host=m_Input; WORDwVersionRequested; WSADATAwsaData; interr; wVersionRequested=MAKEWORD(2,2); err=WSAStartup(wVersionRequested,&wsaData); if(err!=0)return; if(LOBYTE(wsaData.wVersion)!=2|| HIBYTE(wsaData.wVersion)!=2){ WSACleanup(); return; } if((protocol=getprotobyname("icmp"))==NULL)//返回對應于給定協議名的包含名字和協議號 { printf("getprotobynameerror\n");//的protoent結構指針 exit(1); } if((sockfd=socket(AF_INET,SOCK_RAW,protocol->p_proto))<0) { printf("socketerror\n"); exit(1); } if(setsockopt(sockfd,SOL_SOCKET,SO_RCVTIMEO,(char*)&timeout,sizeof(timeout))<0)//設置套接口的選項 fprintf(stderr,"failedtosetrecvtimeout:%d\n",WSAGetLastError()); if(setsockopt(sockfd,SOL_SOCKET,SO_SNDTIMEO,(char*)&timeout,sizeof(timeout))<0) fprintf(stderr,"failedtosetsendtimeout:%d\n",WSAGetLastError()); memset(&dest_addr,0,sizeof(dest_addr)); dest_addr.sin_family=AF_INET; if(host=gethostbyname(par_host))//返回對應于給定主機名的主機信息 { memcpy((char*)&dest_addr.sin_addr,host->h_addr,host->h_length); //resolveaddresstohostname if(host=gethostbyaddr(host->h_addr,4,PF_INET)) par_host=host->h_name; } elseif(dest_addr.sin_addr.s_addr=inet_addr(par_host)==INADDR_NONE) { printf("Unkownhost%s\n",par_host); exit(1); } pid=_getpid(); printf("Pinging%s[%s]:with%dbytesofdata:\n\n",par_host,inet_ntoa(dest_addr.sin_addr),SEND_SIZE); for(i=0;i<SEND_COUNT;i++) { send_packet(); recv_packet(); Sleep(1000); }}//thisalgorithmisreferencedfromother'sunsignedshortcal_chksum(unsignedshort*addr,intlen){ intnleft=len; intsum=0; unsignedshort*w=addr; unsignedshortanswer=0; while(nleft>1) {sum+=*w++; nleft-=2; } if(nleft==1)//處理ICMP報頭為奇數個字節時累加最后一個 {*(unsignedchar*)(&answer)=*(unsignedchar*)w; sum+=answer; } sum=(sum>>16)+(sum&0xffff); sum+=(sum>>16); answer=~sum; returnanswer;}//打包intpack(intpack_no){ intpacksize; structicmp*icmp; packsize=8+SEND_SIZE; icmp=(structicmp*)sendpacket; icmp->icmp_type=ICMP_ECHO; icmp->icmp_code=0; icmp->icmp_chksum=0; icmp->icmp_seq=pack_no; icmp->icmp_id=pid; icmp->icmp_data=GetTickCount(); icmp->icmp_chksum=cal_chksum((unsignedshort*)icmp,packsize);/*校驗算法*/ returnpacksize;}//解包intunpack(char*buf,intlen){ structip*ip; structicmp*icmp; doublertt; intiphdrlen; ip=(structip*)buf; iphdrlen=ip->ip_hl*4; icmp=(structicmp*)(buf+iphdrlen); if((icmp->icmp_type==ICMP_ECHOREPLY)&&(icmp->icmp_id==pid)) { len=len-iphdrlen-8; rtt=GetTickCount()-icmp->icmp_data; printf("Replyfrom%s:bytes=%dtime=%.0fmsTTL=%dicmp_seq=%u\n", inet_ntoa(from_addr.sin_addr), len, rtt, ip->ip_ttl, icmp->icmp_seq); return1; } return0;}//發送voidsend_packet(){ intpacketsize; staticintpack_no=0; packetsize=pack(pack_no++); if(sendto(sockfd,sendpacket,packetsize,0,(structsockaddr*)&dest_addr,sizeof(dest_addr))<0) printf("Destinationhostunreachable.\n"); //printf("sendNO%d\n",pack_no-1);}//接收voidrecv_packet(){ intn,fromlen; intsuccess; fromlen=sizeof(from_addr); do { if((n=recvfrom(sockfd,recvpacket,sizeof(recvpacket),0,(structsockaddr*)&from_addr,&fromlen))>=0) success=unpack(recvpacket,n); elseif(WSAGetLastError()==WSAETIMEDOUT) { printf("Requesttimedout.\n"); return; } }while(!success);}實驗結果總結本次課程設計較好地實現了要求做到的功能，但同