114 lines
2.5 KiB
C++
114 lines
2.5 KiB
C++
#pragma once
|
|
|
|
#ifndef _WIN32
|
|
#include <unistd.h>
|
|
#include <netdb.h>
|
|
#include <netinet/in.h>
|
|
#include <sys/socket.h>
|
|
#define INVALID_SOCKET (-1)
|
|
#define SOCKET int
|
|
#define SOCKET_ERROR (-1)
|
|
#define closesocket close
|
|
#endif
|
|
|
|
#include <time.h>
|
|
|
|
class NTPClient
|
|
{
|
|
public:
|
|
static time_t GetCurrentTimeUTC(const char * ntpserver = NULL)
|
|
{
|
|
#ifdef _WIN32
|
|
WSADATA w;
|
|
int remote_length;
|
|
#else
|
|
socklen_t remote_length;
|
|
#endif
|
|
SOCKET sd = INVALID_SOCKET;
|
|
char ntp_buffer[48];
|
|
time_t current_time = 0;
|
|
struct hostent *hp;
|
|
struct sockaddr_in remote;
|
|
struct sockaddr_in local;
|
|
char host_name[256];
|
|
hostent * host = NULL;
|
|
|
|
do {
|
|
#ifdef _WIN32
|
|
if (WSAStartup(MAKEWORD(2, 2), &w) != 0)
|
|
return 0;
|
|
#endif
|
|
|
|
if ((sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == INVALID_SOCKET)
|
|
break;
|
|
|
|
memset((void *)&remote, '\0', sizeof(struct sockaddr_in));
|
|
|
|
remote.sin_family = AF_INET;
|
|
remote.sin_port = htons(123);
|
|
|
|
if ((host = gethostbyname((ntpserver) ? ntpserver : "time.windows.com")) == NULL)
|
|
break;
|
|
|
|
remote.sin_addr.s_addr = *(u_long *)host->h_addr_list[0];
|
|
|
|
memset((void *)&local, '\0', sizeof(local));
|
|
|
|
local.sin_family = AF_INET;
|
|
local.sin_port = htons(0);
|
|
local.sin_addr.s_addr = htonl(INADDR_ANY);
|
|
|
|
if (::bind(sd, (struct sockaddr *)&local, sizeof(local)) == SOCKET_ERROR)
|
|
break;
|
|
|
|
memset(ntp_buffer, 0, sizeof(ntp_buffer));
|
|
ntp_buffer[0] = 0x1B;
|
|
|
|
remote_length = sizeof(struct sockaddr_in);
|
|
|
|
if (sendto(sd, ntp_buffer, sizeof(ntp_buffer), 0, (struct sockaddr *)&remote, remote_length) == -1)
|
|
break;
|
|
|
|
fd_set fds;
|
|
|
|
FD_ZERO(&fds);
|
|
FD_SET(sd, &fds);
|
|
|
|
timeval timeout;
|
|
timeout.tv_sec = 10;
|
|
timeout.tv_usec = 0;
|
|
|
|
if (select(1, &fds, NULL, NULL, &timeout) != 1)
|
|
break;
|
|
|
|
if (recvfrom(sd, ntp_buffer, sizeof(ntp_buffer), 0, (struct sockaddr *)&remote, &remote_length) < 0)
|
|
break;
|
|
|
|
unsigned int int_part = *(unsigned int *)(ntp_buffer + 40);
|
|
unsigned int fract_part = *(unsigned int *)(ntp_buffer + 44);
|
|
|
|
int_part = SwapEndianness(int_part);
|
|
|
|
current_time = (time_t)(int_part -= 2208988800U);
|
|
}
|
|
while (0);
|
|
|
|
if (sd != INVALID_SOCKET)
|
|
closesocket(sd);
|
|
|
|
#ifdef _WIN32
|
|
WSACleanup();
|
|
#endif
|
|
|
|
return current_time;
|
|
}
|
|
|
|
static unsigned int SwapEndianness(unsigned int x)
|
|
{
|
|
return (unsigned int)(((x & 0x000000ff) << 24) +
|
|
((x & 0x0000ff00) << 8) +
|
|
((x & 0x00ff0000) >> 8) +
|
|
((x & 0xff000000) >> 24));
|
|
}
|
|
};
|