golang ntp协议客户端
NTP（Network Time Protocol，网络时间协议）是由RFC 1305定义的时间同步协议，用来在分布式时间服务器和客户端之间进行时间同步。NTP基于UDP报文进行传输，使用的UDP端口号为123。
使用NTP的目的是对网络内所有具有时钟的设备进行时钟同步，使网络内所有设备的时钟保持一致，从而使设备能够提供基于统一时间的多种应用。
对于运行NTP的本地系统，既可以接收来自其他时钟源的同步，又可以作为时钟源同步其他的时钟，并且可以和其他设备互相同步。
相信文本介绍看多也厌倦了，就不多废话，直接上干活
ntp.go
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 | package mainimport ( "bytes" "encoding/binary")const ( UNIX_STA_TIMESTAMP = 2208988800)/**NTP协议 http://www.ntp.org/documentation.html@author mengdj@outlook.com*/type Ntp struct { //1:32bits Li uint8 //2 bits Vn uint8 //3 bits Mode uint8 //3 bits Stratum uint8 Poll uint8 Precision uint8 //2: RootDelay int32 RootDispersion int32 ReferenceIdentifier int32 //64位时间戳 ReferenceTimestamp uint64 //指示系统时钟最后一次校准的时间 OriginateTimestamp uint64 //指示客户向服务器发起请求的时间 ReceiveTimestamp uint64 //指服务器收到客户请求的时间 TransmitTimestamp uint64 //指示服务器向客户发时间戳的时间}func NewNtp() (p *Ntp) { //其他参数通常都是服务器返回的 p = &Ntp{Li: 0, Vn: 3, Mode: 3, Stratum: 0} return p}/**构建NTP协议信息*/func (this *Ntp) GetBytes() []byte { //注意网络上使用的是大端字节排序 buf := &bytes.Buffer{} head := (this.Li << 6) | (this.Vn << 3) | ((this.Mode << 5) >> 5) binary.Write(buf, binary.BigEndian, uint8(head)) binary.Write(buf, binary.BigEndian, this.Stratum) binary.Write(buf, binary.BigEndian, this.Poll) binary.Write(buf, binary.BigEndian, this.Precision) //写入其他字节数据 binary.Write(buf, binary.BigEndian, this.RootDelay) binary.Write(buf, binary.BigEndian, this.RootDispersion) binary.Write(buf, binary.BigEndian, this.ReferenceIdentifier) binary.Write(buf, binary.BigEndian, this.ReferenceTimestamp) binary.Write(buf, binary.BigEndian, this.OriginateTimestamp) binary.Write(buf, binary.BigEndian, this.ReceiveTimestamp) binary.Write(buf, binary.BigEndian, this.TransmitTimestamp) //[27 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] return buf.Bytes()}func (this *Ntp) Parse(bf []byte, useUnixSec bool) { var ( bit8 uint8 bit32 int32 bit64 uint64 rb *bytes.Reader ) //貌似这binary.Read只能顺序读，不能跳着读，想要跳着读只能使用切片bf rb = bytes.NewReader(bf) binary.Read(rb, binary.BigEndian, &bit8) //向右偏移6位得到前两位LI即可 this.Li = bit8 >> 6 //向右偏移2位,向右偏移5位,得到前中间3位 this.Vn = (bit8 << 2) >> 5 //向左偏移5位，然后右偏移5位得到最后3位 this.Mode = (bit8 << 5) >> 5 binary.Read(rb, binary.BigEndian, &bit8) this.Stratum = bit8 binary.Read(rb, binary.BigEndian, &bit8) this.Poll = bit8 binary.Read(rb, binary.BigEndian, &bit8) this.Precision = bit8 //32bits binary.Read(rb, binary.BigEndian, &bit32) this.RootDelay = bit32 binary.Read(rb, binary.BigEndian, &bit32) this.RootDispersion = bit32 binary.Read(rb, binary.BigEndian, &bit32) this.ReferenceIdentifier = bit32 //以下几个字段都是64位时间戳(NTP都是64位的时间戳) binary.Read(rb, binary.BigEndian, &bit64) this.ReferenceTimestamp = bit64 binary.Read(rb, binary.BigEndian, &bit64) this.OriginateTimestamp = bit64 binary.Read(rb, binary.BigEndian, &bit64) this.ReceiveTimestamp = bit64 binary.Read(rb, binary.BigEndian, &bit64) this.TransmitTimestamp = bit64 //转换为unix时间戳,先左偏移32位拿到64位时间戳的整数部分，然后ntp的起始时间戳 1900年1月1日 0时0分0秒 2208988800 if useUnixSec { this.ReferenceTimestamp = (this.ReceiveTimestamp >> 32) - UNIX_STA_TIMESTAMP if this.OriginateTimestamp > 0 { this.OriginateTimestamp = (this.OriginateTimestamp >> 32) - UNIX_STA_TIMESTAMP } this.ReceiveTimestamp = (this.ReceiveTimestamp >> 32) - UNIX_STA_TIMESTAMP this.TransmitTimestamp = (this.TransmitTimestamp >> 32) - UNIX_STA_TIMESTAMP }} |
main.go
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 | package mainimport ( "fmt" "log" "net")func main() { var ( ntp *Ntp buffer []byte err error ret int ) //链接阿里云NTP服务器,NTP有很多免费服务器可以使用time.windows.com conn, err := net.Dial("udp", "ntp1.aliyun.com:123") defer func() { if err := recover(); err != nil { log.Println(err) } conn.Close() }() ntp = NewNtp() conn.Write(ntp.GetBytes()) buffer = make([]byte, 2048) ret, err = conn.Read(buffer) if err == nil { if ret > 0 { ntp.Parse(buffer, true) fmt.Println(fmt.Sprintf( "LI:%d\r\n版本:%d\r\n模式:%d\r\n精度:%d\r\n轮询:%d\r\n系统精度:%d\r\n延时:%ds\r\n最大误差:%d\r\n时钟表示:%d\r\n时间戳:%d %d %d %d\r\n", ntp.Li, ntp.Vn, ntp.Mode, ntp.Stratum, ntp.Poll, ntp.Precision, ntp.RootDelay, ntp.RootDispersion, ntp.ReferenceIdentifier, ntp.ReferenceTimestamp, ntp.OriginateTimestamp, ntp.ReceiveTimestamp, ntp.TransmitTimestamp, )) } }} |
