NTP服务器接收端的问题
急急~~~~~
为了测试NTP服务器的处理能力,写了两个文档,一个用来专门发送请求,一个专门用来接收服务器返回的请求。我的发送端分可以正常发数据,但是接收那一端却是一个数据也收不到,将两个整合在一起却又可以正常收发,弄不明白是为什么?原来想用bind()来绑定一个NTP端口的,但是运行时提示“无法分配请求的地址”,百思不得其解。后来将端口改大了,就可以通过,但是我要的NTP专用的端口 123,请问如何解决接收数据的问题啊?用了那些强制允许重复绑定的函数也不能正常运行,还是提示“bind error: Cannot assign requested address
”不知道哪位大侠能指点下小弟,感激不尽。
接收端的代码如下:
//ntp_rev.c#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/wait.h>#include <sys/socket.h>#include <sys/types.h>#include <sys/time.h>#include <netinet/in.h>#include <netdb.h>#include <unistd.h>#include <arpa/inet.h>#include <sys/ioctl.h>#define int8 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 NTPSVR "192.168.2.8" //myserver#define NTPPORT 123typedef struct NTPPACKET{ uint8 li_vn_mode; uint8 stratum; uint8 poll; uint8 precision; //有符号整数表示本地时钟精确度 ulong32 root_delay; //到达服务器的一次往返的总延时,是15到16位有符号的定点小数 ulong32 root_dispersion; // 到达服务器的一次标准误差,是15-16位的无符号的定点小数 int8 ref_id[4]; ulong32 reftimestamphigh; //本地时钟最后被设定或校正的时间T4 ulong32 reftimestamplow; ulong32 oritimestamphigh; //向服务器请求分离客户机的时间戳,采用64位时标格式T1 ulong32 oritimestamplow; ulong32 recvtimestamphigh; //向服务器请求到客户机的时间戳,采用64位时标格式T2 ulong32 recvtimestamplow; ulong32 trantimestamphigh; //向客户机答复分离服务器的时间戳,采用64位时标格式T3,用T3来校正本地时间 ulong32 trantimestamplow;}NTPPacket;NTPPacket ntppack,newpack;//定义为long64,解决32位数的符号位问题long64 firsttimestamp,finaltimestamp;long64 diftime,delaytime;void NTP_Init(){ bzero(&ntppack,sizeof(ntppack)); ntppack.li_vn_mode=0x1b;//0|(3<<2)|(3<<5); //获取初始时间戳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 timeval tv,tv1; struct timezone tz; struct sockaddr_in addr; addr.sin_family=AF_INET; //IPV4协议 addr.sin_port =htons(NTPPORT); //NTP专用的123端口 addr.sin_addr.s_addr=inet_addr(NTPSVR);//INADDR_ANY,NTPSVR; //校时服务器 bzero(&(addr.sin_zero),8); //清零 /*build a socket */ if((sockfd=socket(AF_INET,SOCK_DGRAM,0))<0) { perror("create socket error!\n"); exit(1); } /*bind a port*/ // int bDontLinger = 0; //setsockopt( socket, SOL_SOCKET, SO_DONTLINGER, ( const char* )&bDontLinger, sizeof( int ) );// int bReuseaddr=1;// setsockopt(sockfd,SOL_SOCKET ,SO_REUSEADDR,(const char*)&bReuseaddr,sizeof(int));/* if(bind(sockfd,(struct sockaddr *)&addr,sizeof(struct sockaddr))==-1) { perror("bind error"); exit(1); }*/ while(1) { NTP_Init(); //发送数据请求包 // sendto(sockfd,&ntppack,sizeof(ntppack), // 0,(struct sockaddr *)&addr,sizeof(struct sockaddr)); // recvfrom(s,buffer,sizeof(buffer),0,&addr,&addr_len); // sendto(s,buffer,len,0,&addr,addr_len); int recvbyte=0; printf("sockfd %d \n",sockfd); recvbyte=recv(sockfd,&newpack,sizeof(newpack),0); //接收数据在newpack中。 printf("OK %d \n",recvbyte); // printf("OK\n"); if(recvbyte<0) { perror("recv error!\n"); exit(1); } // } //到达客户机时间戳T4 finaltimestamp=time(NULL)+From00to70;//-8*3600; //将网络上传送的大端数据改为小端形式。数据的转换方式 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); diftime=(5-9)>>1; printf("Before Update ,Current time is...\n"); system("date");tv1.tv_sec=newpack.trantimestamphigh - From00to70; //校对时间 settimeofday(&tv1,NULL); printf("Current time is...\n"); system("date"); usleep(3000000);}}