C# NTP时间同步类
添加类 NTPClient
/// <summary> /// SNTPClient is a C# class designed to connect to time servers on the Internet and /// fetch the current date and time. Optionally, it may update the time of the local system. /// The implementation of the protocol is based on the RFC 2030. /// /// Public class members: /// /// Initialize - Sets up data structure and prepares for connection. /// /// Connect - Connects to the time server and populates the data structure. /// It can also update the system time. /// /// IsResponseValid - Returns true if received data is valid and if comes from /// a NTP-compliant time server. /// /// ToString - Returns a string representation of the object. /// /// ----------------------------------------------------------------------------- /// Structure of the standard NTP header (as described in RFC 2030) /// 1 2 3 /// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// |LI | VN |Mode | Stratum | Poll | Precision | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Root Delay | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Root Dispersion | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Reference Identifier | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// | Reference Timestamp (64) | /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// | Originate Timestamp (64) | /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// | Receive Timestamp (64) | /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// | Transmit Timestamp (64) | /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Key Identifier (optional) (32) | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | | /// | | /// | Message Digest (optional) (128) | /// | | /// | | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// /// ----------------------------------------------------------------------------- /// /// SNTP Timestamp Format (as described in RFC 2030) /// 1 2 3 /// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Seconds | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// | Seconds Fraction (0-padded) | /// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /// /// </summary> public class NTPClient { /// <summary> /// SNTP Data Structure Length /// </summary> private const byte SNTPDataLength = 48; /// <summary> /// SNTP Data Structure (as described in RFC 2030) /// </summary> byte[] SNTPData = new byte[SNTPDataLength]; //Offset constants for timestamps in the data structure private const byte offReferenceID = 12; private const byte offReferenceTimestamp = 16; private const byte offOriginateTimestamp = 24; private const byte offReceiveTimestamp = 32; private const byte offTransmitTimestamp = 40; /// <summary> /// Leap Indicator Warns of an impending leap second to be inserted/deleted in the last minute of the current day. 值为“11”时表示告警状态，时钟未被同步。为其他值时NTP本身不做处理 /// </summary> public _LeapIndicator LeapIndicator { get { // Isolate the two most significant bits byte val = (byte)(SNTPData[0] >> 6); switch (val) { case 0: return _LeapIndicator.NoWarning; case 1: return _LeapIndicator.LastMinute61; case 2: return _LeapIndicator.LastMinute59; case 3: goto default; default: return _LeapIndicator.Alarm; } } } /// <summary> /// Version Number Version number of the protocol (3 or 4) NTP的版本号 /// </summary> public byte VersionNumber { get { // Isolate bits 3 - 5 byte val = (byte)((SNTPData[0] & 0x38) >> 3); return val; } } /// <summary> /// Mode 长度为3比特，表示NTP的工作模式。不同的值所表示的含义分别是：0未定义、1表示主动对等体模式、2表示被动对等体模式、3表示客户模式、4表示服务器模式、5表示广播模式或组播模式、6表示此报文为NTP控制报文、7预留给内部使用 /// </summary> public _Mode Mode { get { // Isolate bits 0 - 3 byte val = (byte)(SNTPData[0] & 0x7); switch (val) { case 0: return _Mode.Unknown; case 6: return _Mode.Unknown; case 7: return _Mode.Unknown; default: return _Mode.Unknown; case 1: return _Mode.SymmetricActive; case 2: return _Mode.SymmetricPassive; case 3: return _Mode.Client; case 4: return _Mode.Server; case 5: return _Mode.Broadcast; } } } /// <summary> /// Stratum 系统时钟的层数，取值范围为1～16，它定义了时钟的准确度。层数为1的时钟准确度最高，准确度从1到16依次递减，层数为16的时钟处于未同步状态，不能作为参考时钟 /// </summary> public _Stratum Stratum { get { byte val = (byte)SNTPData[1]; if (val == 0) return _Stratum.Unspecified; else if (val == 1) return _Stratum.PrimaryReference; else if (val <= 15) return _Stratum.SecondaryReference; else return _Stratum.Reserved; } } /// <summary> /// Poll Interval (in seconds) Maximum interval between successive messages 轮询时间，即两个连续NTP报文之间的时间间隔 /// </summary> public uint PollInterval { get { // Thanks to Jim Hollenhorst <hollenho@attbi.com> return (uint)(Math.Pow(2, (sbyte)SNTPData[2])); } } /// <summary> /// Precision (in seconds) Precision of the clock 系统时钟的精度 /// </summary> public double Precision { get { // Thanks to Jim Hollenhorst <hollenho@attbi.com> return (Math.Pow(2, (sbyte)SNTPData[3])); } } /// <summary> /// Root Delay (in milliseconds) Round trip time to the primary reference source NTP服务器到主参考时钟的延迟 /// </summary> public double RootDelay { get { int temp = 0; temp = 256 * (256 * (256 * SNTPData[4] + SNTPData[5]) + SNTPData[6]) + SNTPData[7]; return 1000 * (((double)temp) / 0x10000); } } /// <summary> /// Root Dispersion (in milliseconds) Nominal error relative to the primary reference source 系统时钟相对于主参考时钟的最大误差 /// </summary> public double RootDispersion { get { int temp = 0; temp = 256 * (256 * (256 * SNTPData[8] + SNTPData[9]) + SNTPData[10]) + SNTPData[11]; return 1000 * (((double)temp) / 0x10000); } } /// <summary> /// Reference Identifier Reference identifier (either a 4 character string or an IP address) /// </summary> public string ReferenceID { get { string val = ""; switch (Stratum) { case _Stratum.Unspecified: goto case _Stratum.PrimaryReference; case _Stratum.PrimaryReference: val += (char)SNTPData[offReferenceID + 0]; val += (char)SNTPData[offReferenceID + 1]; val += (char)SNTPData[offReferenceID + 2]; val += (char)SNTPData[offReferenceID + 3]; break; case _Stratum.SecondaryReference: switch (VersionNumber) { case 3: // Version 3, Reference ID is an IPv4 address string Address = SNTPData[offReferenceID + 0].ToString() + "." + SNTPData[offReferenceID + 1].ToString() + "." + SNTPData[offReferenceID + 2].ToString() + "." + SNTPData[offReferenceID + 3].ToString(); try { IPHostEntry Host = Dns.GetHostEntry(Address); val = Host.HostName + " (" + Address + ")"; } catch (Exception) { val = "N/A"; } break; case 4: // Version 4, Reference ID is the timestamp of last update DateTime time = ComputeDate(GetMilliSeconds(offReferenceID)); // Take care of the time zone TimeSpan offspan = TimeZone.CurrentTimeZone.GetUtcOffset(DateTime.Now); val = (time + offspan).ToString(); break; default: val = "N/A"; break; } break; } return val; } } /// <summary> /// Reference Timestamp The time at which the clock was last set or corrected NTP系统时钟最后一次被设定或更新的时间 /// </summary> public DateTime ReferenceTimestamp { get { DateTime time = ComputeDate(GetMilliSeconds(offReferenceTimestamp)); // Take care of the time zone TimeSpan offspan = TimeZone.CurrentTimeZone.GetUtcOffset(DateTime.Now); return time + offspan; } } /// <summary> /// Originate Timestamp (T1) The time at which the request departed the client for the server. 发送报文时的本机时间 /// </summary> public DateTime OriginateTimestamp { get { return ComputeDate(GetMilliSeconds(offOriginateTimestamp)); } } /// <summary> /// Receive Timestamp (T2) The time at which the request arrived at the server. 报文到达NTP服务器时的服务器时间 /// </summary> public DateTime ReceiveTimestamp { get { DateTime time = ComputeDate(GetMilliSeconds(offReceiveTimestamp)); // Take care of the time zone TimeSpan offspan = TimeZone.CurrentTimeZone.GetUtcOffset(DateTime.Now); return time + offspan; } } /// <summary> /// Transmit Timestamp (T3) The time at which the reply departed the server for client. 报文从NTP服务器离开时的服务器时间 /// </summary> public DateTime TransmitTimestamp { get { DateTime time = ComputeDate(GetMilliSeconds(offTransmitTimestamp)); // Take care of the time zone TimeSpan offspan = TimeZone.CurrentTimeZone.GetUtcOffset(DateTime.Now); return time + offspan; } set { SetDate(offTransmitTimestamp, value); } } /// <summary> /// Destination Timestamp (T4) The time at which the reply arrived at the client. 接收到来自NTP服务器返回报文时的本机时间 /// </summary> public DateTime DestinationTimestamp; /// <summary> /// Round trip delay (in milliseconds) The time between the departure of request and arrival of reply 报文从本地到NTP服务器的往返时间 /// </summary> public double RoundTripDelay { get { // Thanks to DNH <dnharris@csrlink.net> TimeSpan span = (DestinationTimestamp - OriginateTimestamp) - (ReceiveTimestamp - TransmitTimestamp); return span.TotalMilliseconds; } } /// <summary> /// Local clock offset (in milliseconds) The offset of the local clock relative to the primary reference source.本机相对于NTP服务器（主时钟）的时间差 /// </summary> public double LocalClockOffset { get { // Thanks to DNH <dnharris@csrlink.net> TimeSpan span = (ReceiveTimestamp - OriginateTimestamp) + (TransmitTimestamp - DestinationTimestamp); return span.TotalMilliseconds / 2; } } /// <summary> /// Compute date, given the number of milliseconds since January 1, 1900 /// </summary> /// <param name="milliseconds"></param> /// <returns></returns> private DateTime ComputeDate(ulong milliseconds) { TimeSpan span = TimeSpan.FromMilliseconds((double)milliseconds); DateTime time = new DateTime(1900, 1, 1); time += span; return time; } /// <summary> /// Compute the number of milliseconds, given the offset of a 8-byte array /// </summary> /// <param name="offset"></param> /// <returns></returns> private ulong GetMilliSeconds(byte offset) { ulong intpart = 0, fractpart = 0; for (int i = 0; i <= 3; i++) { intpart = 256 * intpart + SNTPData[offset + i]; } for (int i = 4; i <= 7; i++) { fractpart = 256 * fractpart + SNTPData[offset + i]; } ulong milliseconds = intpart * 1000 + (fractpart * 1000) / 0x100000000L; return milliseconds; } /// <summary> /// Compute the 8-byte array, given the date /// </summary> /// <param name="offset"></param> /// <param name="date"></param> private void SetDate(byte offset, DateTime date) { ulong intpart = 0, fractpart = 0; DateTime StartOfCentury = new DateTime(1900, 1, 1, 0, 0, 0); // January 1, 1900 12:00 AM ulong milliseconds = (ulong)(date - StartOfCentury).TotalMilliseconds; intpart = milliseconds / 1000; fractpart = ((milliseconds % 1000) * 0x100000000L) / 1000; ulong temp = intpart; for (int i = 3; i >= 0; i--) { SNTPData[offset + i] = (byte)(temp % 256); temp = temp / 256; } temp = fractpart; for (int i = 7; i >= 4; i--) { SNTPData[offset + i] = (byte)(temp % 256); temp = temp / 256; } } /// <summary> /// Initialize the NTPClient data /// </summary> private void Initialize() { // Set version number to 4 and Mode to 3 (client) SNTPData[0] = 0x1B; // Initialize all other fields with 0 for (int i = 1; i < 48; i++) { SNTPData[i] = 0; } // Initialize the transmit timestamp TransmitTimestamp = DateTime.Now; } /// <summary> /// The IPAddress of the time server we're connecting to /// </summary> private IPAddress serverAddress = null; /// <summary> /// Constractor with HostName /// </summary> /// <param name="host"></param> public NTPClient(string host) { //string host = "ntp1.aliyun.com"; //string host = "0.asia.pool.ntp.org"; //string host = "1.asia.pool.ntp.org"; //string host = "www.ntp.org/"; // Resolve server address IPHostEntry hostadd = Dns.GetHostEntry(host); foreach (IPAddress address in hostadd.AddressList) { if (address.AddressFamily == AddressFamily.InterNetwork) //只支持IPV4协议的IP地址 { serverAddress = address; break; } } if (serverAddress == null) throw new Exception("Can't get any ipaddress infomation"); } /// <summary> /// Constractor with IPAddress /// </summary> /// <param name="address"></param> public NTPClient(IPAddress address) { if (address == null) throw new Exception("Can't get any ipaddress infomation"); serverAddress = address; } /// <summary> /// Connect to the time server and update system time /// </summary> /// <param name="updateSystemTime"></param> public void Connect(bool updateSystemTime, int timeout = 3000) { IPEndPoint EPhost = new IPEndPoint(serverAddress, 123); //Connect the time server using (UdpClient TimeSocket = new UdpClient()) { TimeSocket.Connect(EPhost); // Initialize data structure Initialize(); TimeSocket.Send(SNTPData, SNTPData.Length); TimeSocket.Client.ReceiveTimeout = timeout; SNTPData = TimeSocket.Receive(ref EPhost); if (!IsResponseValid) throw new Exception("Invalid response from " + serverAddress.ToString()); } DestinationTimestamp = DateTime.Now; if (updateSystemTime) SetTime(); } /// <summary> /// Check if the response from server is valid /// </summary> /// <returns></returns> public bool IsResponseValid { get { return !(SNTPData.Length < SNTPDataLength || Mode != _Mode.Server); } } /// <summary> /// Converts the object to string /// </summary> /// <returns></returns> public override string ToString() { StringBuilder sb = new StringBuilder(512); sb.Append("Leap Indicator: "); switch (LeapIndicator) { case _LeapIndicator.NoWarning: sb.Append("No warning"); break; case _LeapIndicator.LastMinute61: sb.Append("Last minute has 61 seconds"); break; case _LeapIndicator.LastMinute59: sb.Append("Last minute has 59 seconds"); break; case _LeapIndicator.Alarm: sb.Append("Alarm Condition (clock not synchronized)"); break; } sb.AppendFormat("\r\nVersion number: {0}\r\n", VersionNumber); sb.Append("Mode: "); switch (Mode) { case _Mode.Unknown: sb.Append("Unknown"); break; case _Mode.SymmetricActive: sb.Append("Symmetric Active"); break; case _Mode.SymmetricPassive: sb.Append("Symmetric Pasive"); break; case _Mode.Client: sb.Append("Client"); break; case _Mode.Server: sb.Append("Server"); break; case _Mode.Broadcast: sb.Append("Broadcast"); break; } sb.Append("\r\nStratum: "); switch (Stratum) { case _Stratum.Unspecified: case _Stratum.Reserved: sb.Append("Unspecified"); break; case _Stratum.PrimaryReference: sb.Append("Primary Reference"); break; case _Stratum.SecondaryReference: sb.Append("Secondary Reference"); break; } sb.AppendFormat("\r\nLocal Time T3: {0:yyyy-MM-dd HH:mm:ss:fff}", TransmitTimestamp); sb.AppendFormat("\r\nDestination Time T4: {0:yyyy-MM-dd HH:mm:ss:fff}", DestinationTimestamp); sb.AppendFormat("\r\nPrecision: {0} s", Precision); sb.AppendFormat("\r\nPoll Interval:{0} s", PollInterval); sb.AppendFormat("\r\nReference ID: {0}", ReferenceID.ToString().Replace("\0", string.Empty)); sb.AppendFormat("\r\nRoot Delay: {0} ms", RootDelay); sb.AppendFormat("\r\nRoot Dispersion: {0} ms", RootDispersion); sb.AppendFormat("\r\nRound Trip Delay: {0} ms", RoundTripDelay); sb.AppendFormat("\r\nLocal Clock Offset: {0} ms", LocalClockOffset); sb.AppendFormat("\r\nReferenceTimestamp: {0:yyyy-MM-dd HH:mm:ss:fff}", ReferenceTimestamp); sb.Append("\r\n"); return sb.ToString(); } /// <summary> /// SYSTEMTIME structure used by SetSystemTime /// </summary> [StructLayoutAttribute(LayoutKind.Sequential)] private struct SYSTEMTIME { public short year; public short month; public short dayOfWeek; public short day; public short hour; public short minute; public short second; public short milliseconds; } [DllImport("kernel32.dll")] static extern bool SetLocalTime(ref SYSTEMTIME time); /// <summary> /// Set system time according to transmit timestamp 把本地时间设置为获取到的时钟时间 /// </summary> public void SetTime() { SYSTEMTIME st; DateTime trts = DateTime.Now.AddMilliseconds(LocalClockOffset); st.year = (short)trts.Year; st.month = (short)trts.Month; st.dayOfWeek = (short)trts.DayOfWeek; st.day = (short)trts.Day; st.hour = (short)trts.Hour; st.minute = (short)trts.Minute; st.second = (short)trts.Second; st.milliseconds = (short)trts.Millisecond; SetLocalTime(ref st); } } /// <summary> /// Leap indicator field values /// </summary> public enum _LeapIndicator { NoWarning, // 0 - No warning LastMinute61, // 1 - Last minute has 61 seconds LastMinute59, // 2 - Last minute has 59 seconds Alarm // 3 - Alarm condition (clock not synchronized) } /// <summary> /// Mode field values /// </summary> public enum _Mode { SymmetricActive, // 1 - Symmetric active SymmetricPassive, // 2 - Symmetric pasive Client, // 3 - Client Server, // 4 - Server Broadcast, // 5 - Broadcast Unknown // 0, 6, 7 - Reserved } /// <summary> /// Stratum field values /// </summary> public enum _Stratum { Unspecified, // 0 - unspecified or unavailable PrimaryReference, // 1 - primary reference (e.g. radio-clock) SecondaryReference, // 2-15 - secondary reference (via NTP or SNTP) Reserved // 16-255 - reserved }
使用时：
//IPAddress ntpserver = IPAddress.Parse("192.39.109.140"); //NTP Server string ntpserver = "ntp1.aliyun.com"; NTPClient client = new NTPClient(ntpserver); client.Connect(true); //参数为false时只从服务器获取信息，为true时同时自动更新本机时间
