mirror of
https://github.com/JamesonHuang/OpenWrt_Luci_Lua.git
synced 2024-11-27 15:30:11 +00:00
166 lines
3.4 KiB
C
166 lines
3.4 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <sys/time.h> /* gettimeofday() */
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netdb.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <time.h> /* for time() and ctime() */
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/*
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* rfc1305的ntp时间中，时间为64bit，记录1900年后的秒数（utc格式）
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* 高32位是整数部分，低32位是小数部分*/
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#define UTC_NTP 2208988800U /* 1970 - 1900 */
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/* get Timestamp for NTP in LOCAL ENDIAN */
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void gettime64(uint32_t ts[])
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{
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struct timeval tv;
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gettimeofday(&tv, NULL);
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ts[0] = tv.tv_sec + UTC_NTP;
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ts[1] = (4294*(tv.tv_usec)) + ((1981*(tv.tv_usec))>>11);
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}
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int die(const char *msg)
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{
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fputs(msg, stderr);
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exit(-1);
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}
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int useage(const char *path)
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{
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printf("Useage:\n\t%s <server address>\n", path);
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return 1;
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}
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//开始连接服务器
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int open_connect(const char* server)
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{
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int s;
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struct addrinfo *saddr;
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/* printf("Connecting to server: %s\n", server); */
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s = socket(AF_INET, SOCK_DGRAM, 0);
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if (s == -1) {
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die("Can not create socket.\n");
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}
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if (0 != getaddrinfo(server, "123", NULL, &saddr)) {
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die("Server address not correct.\n");
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}
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if (connect(s, saddr->ai_addr, saddr->ai_addrlen) != 0) {
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die("Connect error\n");
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}
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freeaddrinfo(saddr);
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return s;
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}
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//发送请求报文
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void request(int fd)
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{
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unsigned char buf[48] = {0};
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uint32_t tts[2]; /* Transmit Timestamp */
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/* LI VN MODE = 00 100 011*/
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/* MODE：3表示客户模式，4表示服务器模式*/
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buf[0] = 0x23;
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gettime64(tts);
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//此处将Originate Timestamp设置在Transmit Timestamp处
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(*(uint32_t *)&buf[40]) = htonl(tts[0]);
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(*(uint32_t *)&buf[44])= htonl(tts[1]);
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if (send(fd, buf, 48, 0) !=48 ) {
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die("Send error\n");
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}
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}
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//获得NTP应答报文
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void get_reply(int fd)
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{
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unsigned char buf[48];
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uint32_t *pt;
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// uint32_t t_last_update[2]; /* Reference Timestamp @ Server */
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uint32_t t1[2]; /* t1 = Originate Timestamp,即NTP请求报文离开发送端时发送端的本地时间 */
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uint32_t t2[2]; /* t2 = Receive Timestamp @ Server,即NTP请求报文到达接收端时接收端的本地时间 */
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uint32_t t3[2]; /* t3 = Transmit Timestamp @ Server,即应答报文离开应答者时应答者的本地时间 */
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uint32_t t4[2]; /* t4 = Receive Timestamp @ Client */
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double T1, T2, T3, T4;
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double tfrac = 4294967296.0;
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time_t curr_time;
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time_t diff_sec;
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if (recv(fd, buf, 48, 0) < 48) {
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die("Receive error\n");
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}
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gettime64(t4);
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pt = (uint32_t *)&buf[24];
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t1[0] = htonl(*pt++);
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t1[1] = htonl(*pt++);
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t2[0] = htonl(*pt++);
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t2[1] = htonl(*pt++);
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t3[0] = htonl(*pt++);
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t3[1] = htonl(*pt++);
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/* t1 = Transmit Timestamp @ Client */
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/*
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* (Version=4, Mode=Server,
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* Stratum = 0-15, etc.)*/
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T1 = t1[0] + t1[1]/tfrac;
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T2 = t2[0] + t2[1]/tfrac;
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T3 = t3[0] + t3[1]/tfrac;
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T4 = t4[0] + t4[1]/tfrac;
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//delay：NTP报文的往返时延
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//offset：client与server的时间差
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printf( "\ndelay = %lf\n"
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"offset = %lf\n\n",
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(T4-T1) - (T3-T2),
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((T2 - T1) + (T3 - T4)) /2
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);
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diff_sec = ((int32_t)(t2[0] - t1[0]) + (int32_t)(t3[0] - t4[0])) /2;
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curr_time = time(NULL) - diff_sec;
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printf("Current Time at Server: %s\n", ctime(&curr_time));
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printf("Current TimeStamp at Server: %d\n", (int)curr_time);
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}
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int client(const char* server)
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{
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int fd;
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fd = open_connect(server);
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request(fd);
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get_reply(fd);
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close(fd);
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return 0;
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}
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int main(int argc, char *argv[], char **env)
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{
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while(1)
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{
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if (argc < 2)
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{
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return useage(argv[0]);
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}
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//return client(argv[1]);
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client(argv[1]);
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sleep(3);
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}
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}
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