timesync

Documentation

Overview

Package timesync is used to check system time reliability by communicating with NTP time servers.

Index

• Constants
• Variables
• func CheckMessageDrift(data int64) bool
• func CheckSystemClockDrift() (time.Duration, error)
• type NtpPacket
  • func (n *NtpPacket) Time() time.Time

Constants

const (
	// MaxAllowedMessageDrift is the time we limit we receive and handle delivered messages within.
	MaxAllowedMessageDrift = 10 * time.Minute
	// NtpOffset is 70 years in seconds since ntp counts from 1900 and unix from 1970.
	NtpOffset = 2208988800
	// DefaultNtpPort is the ntp protocol port.
	DefaultNtpPort = "123"
)

Variables

var (
	DefaultServers = []string{
		"0.pool.ntp.org",
		"1.pool.ntp.org",
		"time.google.com",
		"time1.google.com",
		"time.asia.apple.com",
		"time.americas.apple.com",
	}
)

DefaultServer is a list of relay on more than one server.

Functions

func CheckMessageDrift

func CheckMessageDrift(data int64) bool

CheckMessageDrift checks if a given message timestamp is too far from our local clock.

func CheckSystemClockDrift

func CheckSystemClockDrift() (time.Duration, error)

CheckSystemClockDrift is comparing our clock to the collected ntp data, and returns the drift and an error when drift reading failed or exceeds our preset MaxAllowedDrift

Types

type NtpPacket

type NtpPacket struct {
	Settings       uint8  // leap yr indicator, ver number, and mode
	Stratum        uint8  // stratum of local clock
	Poll           int8   // poll exponent
	Precision      int8   // precision exponent
	RootDelay      uint32 // root delay
	RootDispersion uint32 // root dispersion
	ReferenceID    uint32 // reference id
	RefTimeSec     uint32 // reference timestamp sec
	RefTimeFrac    uint32 // reference timestamp fractional
	OrigTimeSec    uint32 // origin time secs
	OrigTimeFrac   uint32 // origin time fractional
	RxTimeSec      uint32 // receive time secs
	RxTimeFrac     uint32 // receive time frac3
	TxTimeSec      uint32 // transmit time secs
	TxTimeFrac     uint32 // transmit time frac

}

NtpPacket is a 48 bytes packet used for querying ntp information.

func (*NtpPacket) Time

func (n *NtpPacket) Time() time.Time

Time makes a Time struct from NtpPacket data.