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* github.com/miekg/dns * Greatly simplify the logic for handling serial numbers. Related code was all over the place. Now it is abstracted into one testable method makeSoa. This simplifies code in many other places. * Update docs/_providers/bind.md: Edit old text. Add SOA description. * SOA records are now treated like any other record internally. You still can't specify them in dnsconfig.js, but that's by design. * The URL for issue 491 was wrong in many places * BIND: Clarify GENERATE_ZONEFILE message
75 lines
2.2 KiB
Go
75 lines
2.2 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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// Assertions that should never happen.
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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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