restructure package, rename module/repo

ntp/definitions.go

@@ -0,0 +1,61 @@
+package ntp
+
+// LeapIndicator represents the leap second indicator.
+// It indicates whether there is no warning, an extra second (61 seconds in the last minute),
+// or a missing second (59 seconds in the last minute).
+type LeapIndicator uint8
+
+const (
+	LeapNoWarning    LeapIndicator = iota // no warning
+	LeapLastMinute61                      // last minute 61
+	LeapLastMinute59                      // last minute 59
+)
+
+// Stratum represents the stratum level of the NTP server.
+type Stratum uint8
+
+const (
+	// If the Stratum field is 0, which implies unspecified or invalid, the
+	// Reference Identifier field can be used to convey messages useful for
+	// status reporting and access control.  These are called Kiss-o'-Death
+	// (KoD) packets and the ASCII messages they convey are called kiss codes.
+	StratumUnspecified Stratum = 0  // unspecified
+	StratumPrimary     Stratum = 1  // primary
+	StratumUnsync      Stratum = 16 // unsynchronized
+)
+
+// String returns a human readable representation of the Stratum.
+func (s Stratum) String() string {
+	switch s {
+	case 0:
+		return "unspecified"
+	case 1:
+		return "primary"
+	case 16:
+		return "unsynchronized"
+	}
+	if s < 16 {
+		return "secondary"
+	}
+	return "invalid"
+}
+
+func (s Stratum) IsSecondary() bool {
+	return s > 1 && s < 16
+}
+
+// Mode represents the mode of the NTP message.
+// It can be undefined, symmetric active, symmetric passive, client, server, broadcast,
+// NTP control message, or private use.
+type Mode uint8
+
+const (
+	modeUndef             Mode = iota // undefined
+	ModeSymmetricActive               // symmetric active
+	ModeSymmetricPassive              // symmetric passive
+	ModeClient                        // client
+	ModeServer                        // server
+	ModeBroadcast                     // broadcast
+	ModeNTPControlMessage             // control message
+	ModePrivateUse                    // private use
+)