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72 lines
2.1 KiB
Go
72 lines
2.1 KiB
Go
package bind
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import (
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"log"
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"strconv"
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"strings"
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"time"
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)
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var nowFunc = time.Now
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// generateSerial takes an old SOA serial number and increments it.
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func generateSerial(oldSerial uint32) uint32 {
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// Serial numbers are in the format yyyymmddvv
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// where vv is a version count that starts at 01 each day.
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// Multiple serial numbers generated on the same day increase vv.
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// If the old serial number is not in this format, it gets replaced
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// with the new format. However if that would mean a new serial number
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// that is smaller than the old one, we punt and increment the old number.
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// At no time will a serial number == 0 be returned.
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original := oldSerial
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oldSerialStr := strconv.FormatUint(uint64(oldSerial), 10)
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var newSerial uint32
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// Make draft new serial number:
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today := nowFunc().UTC()
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todayStr := today.Format("20060102")
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version := uint32(1)
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todayNum, err := strconv.ParseUint(todayStr, 10, 32)
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if err != nil {
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log.Fatalf("new serial won't fit in 32 bits: %v", err)
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}
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draft := uint32(todayNum)*100 + version
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method := "none" // Used only in debugging.
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if oldSerial > draft {
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// If old_serial was really slow, upgrade to new yyyymmddvv standard:
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method = "o>d"
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newSerial = oldSerial + 1
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newSerial = oldSerial + 1
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} else if oldSerial == draft {
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// Edge case: increment old serial:
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method = "o=d"
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newSerial = draft + 1
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} else if len(oldSerialStr) != 10 {
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// If old_serial is wrong number of digits, upgrade to yyyymmddvv standard:
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method = "len!=10"
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newSerial = draft
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} else if strings.HasPrefix(oldSerialStr, todayStr) {
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// If old_serial just needs to be incremented:
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method = "prefix"
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newSerial = oldSerial + 1
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} else {
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// First serial number to be requested today:
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method = "default"
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newSerial = draft
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}
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if newSerial == 0 {
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// We never return 0 as the serial number.
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newSerial = 1
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}
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if oldSerial == newSerial {
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log.Fatalf("%v: old_serial == new_serial (%v == %v) draft=%v method=%v", original, oldSerial, newSerial, draft, method)
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}
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if oldSerial > newSerial {
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log.Fatalf("%v: old_serial > new_serial (%v > %v) draft=%v method=%v", original, oldSerial, newSerial, draft, method)
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}
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return newSerial
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}
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