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char #define uint8 unsigned char #define uint32 unsigned int #define ulong32 unsigned long #define long32 long #define int32 int #define long64 long long #define debug //3600s*24h*(365days*70years+17days) #define From00to70 0x83aa7e80U #define NTPSVR1 "132.163.4.102" //USA #define NTPSVR2 "132.163.135.132" //USA #define NTPSVR3 "192.53.103.103" //Germany #define NTPPORT 123 typedef struct NTPPACKET { uint8 li_vn_mode; uint8 stratum; uint8 poll; uint8 precision; ulong32 root_delay; ulong32 root_dispersion; int8 ref_id[4]; ulong32 reftimestamphigh; ulong32 reftimestamplow; ulong32 oritimestamphigh; ulong32 oritimestamplow; ulong32 recvtimestamphigh; ulong32 recvtimestamplow; ulong32 trantimestamphigh; ulong32 trantimestamplow; }NTPPacket; NTPPacket ntppack,newpack; //定義為long64,解決32位數(shù)的符號位問題 long64 firsttimestamp,finaltimestamp; long64 diftime,delaytime; void NTP_Init() { bzero(&ntppack,sizeof(ntppack)); ntppack.li_vn_mode=0x1b;//0|(3<<2)|(3<<5); //獲取初始時間戳T1 firsttimestamp="From00to70"+time(NULL);//-8*3600; ntppack.oritimestamphigh=htonl(firsttimestamp); } int main() { // ulong32 clienttime; // ulong32 diftime,firsttimestamp,finaltimestamp; fd_set inset1; int32 sockfd; struct tim tv,tv1; struct timezone tz; struct sockaddr_in addr; // printf("%d,%d,%d/n",&ntppack.li_vn_mode,&ntppack.stratum,&ntppack.poll); // printf("%d %ld/n",sizeof(NTPPacket),sizeof(ntppack)); // printf("%ld/n",time(NULL)); if((sockfd=socket(AF_INET,SOCK_DGRAM,0))<0) { perror("create socket error!/n"); exit(1); } addr.sin_family=AF_INET; //IPV4協(xié)議 addr.sin_port =htons(NTPPORT); //NTP專用的123端口 addr.sin_addr.s_addr=inet_addr(NTPSVR1); //校時服務(wù)器 bzero(&(addr.sin_zero),8); //清零 //wait 5s tv.tv_sec=10; //select等待時間為10S tv.tv_usec=0; FD_ZERO(&inset1); FD_SET(sockfd,&inset1); NTP_Init(); //發(fā)送數(shù)據(jù)請求包 sendto(sockfd,&ntppack,sizeof(ntppack),0,(struct sockaddr *)&addr,sizeof(struct sockaddr)); //select巡視 if(select(sockfd+1,&inset1,NULL,NULL,&tv)<0) { perror("select error!/n"); exit(1); } else { //printf("OK/n"); if(FD_ISSET(sockfd,&inset1)) { // printf("OK/n"); if(recv(sockfd,&newpack,sizeof(newpack),0)<0) //接收數(shù)據(jù)在newpack中。 { perror("recv error!/n"); exit(1); } } } //到達(dá)客戶機(jī)時間戳T4 finaltimestamp=time(NULL)+From00to70;//-8*3600; //將網(wǎng)絡(luò)上傳送的大端數(shù)據(jù)改為小端形式。 newpack.root_delay= ntohl(newpack.root_delay); newpack.root_dispersion= ntohl(newpack.root_dispersion); newpack.reftimestamphigh=ntohl(newpack.reftimestamphigh); newpack.reftimestamplow= ntohl(newpack.reftimestamplow); newpack.oritimestamphigh= ntohl(newpack.oritimestamphigh); newpack.oritimestamplow= ntohl(newpack.oritimestamplow); newpack.recvtimestamphigh= ntohl(newpack.recvtimestamphigh); newpack.recvtimestamplow= ntohl(newpack.recvtimestamplow); newpack.trantimestamphigh= ntohl(newpack.trantimestamphigh); newpack.trantimestamplow= ntohl(newpack.trantimestamplow); //求出客戶機(jī)跟服務(wù)器的時間差=((T2-T1)+(T3-T4))/2 diftime=((newpack.recvtimestamphigh-firsttimestamp)+(newpack.trantimestamphigh-finaltimestamp))>>1; //求出延時 delaytime=((newpack.recvtimestamphigh-firsttimestamp)-(newpack.trantimestamphigh-finaltimestamp))>>1; //diftime=(5-9)>>1; //求出真正時間的時間戳 tv1.tv_sec=time(NULL)+diftime+delaytime; tv1.tv_usec=0; //tz. #ifdef debug printf("/n/ndebug information .../n/n"); printf("time(NULL) is %ld/n",time(NULL)); printf("different time is %ld/n",diftime); printf("delaytime is %ld/n",delaytime); printf("time(NULL)+diftime+delaytime=%ld/n",time(NULL)+diftime+delaytime); printf("tv1.tv_sec is %ld/n/n", tv1.tv_sec); #endif settimeofday(&tv1,NULL); //diftime=diftime-From00to70; #ifdef debug //printf("different time is %ld/n",diftime); printf("delay time is %ld/n",delaytime); //printf("firsttimestamp is %x/n",time(NULL)); printf("newpack.tran is %ld/n",newpack.trantimestamphigh); printf("newpack.recv is %ld/n",newpack.recvtimestamphigh); printf("firsttimestamp is %ld/n",firsttimestamp); printf("finaltimestamp is %ld/n",finaltimestamp); printf("newpack.recv-firsttimestamp is %ld/n",newpack.recvtimestamphigh-firsttimestamp); printf("newpack.tran-finaltimestamp is %ld/n",newpack.trantimestamphigh-finaltimestamp); printf("(recv-first)+(ftran-final) is %ld/n",(newpack.recvtimestamphigh-firsttimestamp)+(newpack.trantimestamphigh-finaltimestamp)); printf("((recv-first)+(ftran-final))>>1 is %ld/n",((newpack.recvtimestamphigh-firsttimestamp)+(newpack.trantimestamphigh-finaltimestamp))>>1); printf("different time is %ld/n/n",diftime); printf("sizeof(long long) is:%d/n",sizeof(long long)); printf("Current time is.../n"); system("date"); #endif } |
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