SimpleRemoter/server/2015Remote/DateVerify.h

#pragma once

#include <iostream>
#include <ctime>
#include <WinSock2.h>
#include <Windows.h>
#pragma comment(lib, "ws2_32.lib")

// <20>й<EFBFBD><D0B9><EFBFBD>½<EFBFBD>Ż<EFBFBD><C5BB><EFBFBD>NTP<54><50><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>б<EFBFBD>
const char* CN_NTP_SERVERS[] = {
	"ntp.aliyun.com",
	"time1.aliyun.com",
	"ntp1.tencent.com",
	"time.edu.cn",
	"ntp.tuna.tsinghua.edu.cn",
	"cn.ntp.org.cn",
};
const int CN_NTP_COUNT = sizeof(CN_NTP_SERVERS) / sizeof(CN_NTP_SERVERS[0]);
const int NTP_PORT = 123;
const uint64_t NTP_EPOCH_OFFSET = 2208988800ULL;

// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ƿ<EFBFBD><C7B7><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
class DateVerify
{
private:
	// <20><>ʼ<EFBFBD><CABC>Winsock
	bool initWinsock() {
		WSADATA wsaData;
		return WSAStartup(MAKEWORD(2, 2), &wsaData) == 0;
	}

	// <20><>ָ<EFBFBD><D6B8>NTP<54><50><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȡʱ<C8A1><CAB1>
	time_t getTimeFromServer(const char* server) {
		SOCKET sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
		if (sock == INVALID_SOCKET) return 0;

		sockaddr_in serverAddr{};
		serverAddr.sin_family = AF_INET;
		serverAddr.sin_port = htons(NTP_PORT);

		// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
		hostent* host = gethostbyname(server);
		if (!host) {
			closesocket(sock);
			return 0;
		}
		serverAddr.sin_addr.s_addr = *((unsigned long*)host->h_addr_list[0]);

		// <20><><EFBFBD>ó<EFBFBD>ʱ
		DWORD timeout = 2000; // 2<>볬ʱ
		setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (char*)&timeout, sizeof(timeout));

		// ׼<><D7BC>NTP<54><50><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
		char ntpPacket[48] = { 0 };
		ntpPacket[0] = 0x1B; // LI=0, VN=3, Mode=3

		// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
		if (sendto(sock, ntpPacket, sizeof(ntpPacket), 0,
			(sockaddr*)&serverAddr, sizeof(serverAddr)) == SOCKET_ERROR) {
			closesocket(sock);
			return 0;
		}

		// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ӧ
		if (recv(sock, ntpPacket, sizeof(ntpPacket), 0) <= 0) {
			closesocket(sock);
			return 0;
		}

		closesocket(sock);

		// <20><><EFBFBD><EFBFBD>NTPʱ<50><CAB1>
		uint32_t ntpTime = ntohl(*((uint32_t*)(ntpPacket + 40)));
		return ntpTime - NTP_EPOCH_OFFSET;
	}

	// <20><>ȡ<EFBFBD><C8A1><EFBFBD><EFBFBD>ʱ<EFBFBD>䣨<EFBFBD><E4A3A8><EFBFBD>Զ<EFBFBD><D4B6><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
	time_t getNetworkTimeInChina() {
		if (!initWinsock()) return 0;

		time_t result = 0;
		for (int i = 0; i < CN_NTP_COUNT && result == 0; i++) {
			result = getTimeFromServer(CN_NTP_SERVERS[i]);
			if (result != 0) {
				break;
			}
		}

		WSACleanup();
		return result;
	}

	// <20><><EFBFBD>·<EFBFBD><C2B7><EFBFBD>дת<D0B4><D7AA>Ϊ<EFBFBD><CEAA><EFBFBD><EFBFBD>(1-12)
	int monthAbbrevToNumber(const std::string& month) {
		static const std::map<std::string, int> months = {
			{"Jan", 1}, {"Feb", 2}, {"Mar", 3}, {"Apr", 4},
			{"May", 5}, {"Jun", 6}, {"Jul", 7}, {"Aug", 8},
			{"Sep", 9}, {"Oct", 10}, {"Nov", 11}, {"Dec", 12}
		};
		auto it = months.find(month);
		return (it != months.end()) ? it->second : 0;
	}

	// <20><><EFBFBD><EFBFBD>__DATE__<5F>ַ<EFBFBD><D6B7><EFBFBD>Ϊtm<74>ṹ
	tm parseCompileDate(const char* compileDate) {
		tm tmCompile = { 0 };
		std::string monthStr(compileDate, 3);
		std::string dayStr(compileDate + 4, 2);
		std::string yearStr(compileDate + 7, 4);

		tmCompile.tm_year = std::stoi(yearStr) - 1900;
		tmCompile.tm_mon = monthAbbrevToNumber(monthStr) - 1;
		tmCompile.tm_mday = std::stoi(dayStr);

		return tmCompile;
	}

	// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>֮<EFBFBD><D6AE><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
	int daysBetweenDates(const tm& date1, const tm& date2) {
		auto timeToTimePoint = [](const tm& tmTime) {
			std::time_t tt = mktime(const_cast<tm*>(&tmTime));
			return std::chrono::system_clock::from_time_t(tt);
		};

		auto tp1 = timeToTimePoint(date1);
		auto tp2 = timeToTimePoint(date2);

		auto duration = tp1 > tp2 ? tp1 - tp2 : tp2 - tp1;
		return std::chrono::duration_cast<std::chrono::hours>(duration).count() / 24;
	}

	// <20><>ȡ<EFBFBD><C8A1>ǰ<EFBFBD><C7B0><EFBFBD><EFBFBD>
	tm getCurrentDate() {
		std::time_t now = std::time(nullptr);
		tm tmNow = *std::localtime(&now);
		tmNow.tm_hour = 0;
		tmNow.tm_min = 0;
		tmNow.tm_sec = 0;
		return tmNow;
	}

	// <20><>֤<EFBFBD><D6A4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ƿ<EFBFBD><C7B7><EFBFBD><EFBFBD>޸<EFBFBD>
	bool isLocalDateModified() {
		time_t networkTime = getNetworkTimeInChina();
		if (networkTime == 0) {
			return true; // <20>޷<EFBFBD><DEB7><EFBFBD>֤
		}

		time_t localTime = time(nullptr);
		double diffDays = difftime(networkTime, localTime) / 86400.0;

		// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>1<EFBFBD><31><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EEA3A8><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ӳٺ<D3B3>ʱ<EFBFBD><CAB1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>أ<EFBFBD>
		if (fabs(diffDays) > 1.0) {
			return true;
		}

		return false;
	}

public:

	bool isTrail(int trailDays=7) {
		if (isLocalDateModified())
			return false;

		tm tmCompile = parseCompileDate(__DATE__), tmCurrent = getCurrentDate();

		// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
		int daysDiff = daysBetweenDates(tmCompile, tmCurrent);

		return daysDiff <= trailDays;
	}
};