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e294c95582
Return a delegation when seeing one while traversing the tree in search of an answer. Put the SOA and NS record in the zone.Apex as these are to be handled somewhat special. Lowercase record on insert to make compares easier. This lowercases all RR that have domain names in their rdata as well.
60 lines
1.3 KiB
Go
60 lines
1.3 KiB
Go
package middleware
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import (
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"bytes"
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"github.com/miekg/dns"
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)
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// Less returns <0 when a is less than b, 0 when they are equal and
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// >0 when a is larger than b.
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// The function orders names in DNSSEC canonical order: RFC 4034s section-6.1
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//
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// See http://bert-hubert.blogspot.co.uk/2015/10/how-to-do-fast-canonical-ordering-of.html
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// for a blog article on this implementation.
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//
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// The values of a and b are *not* lowercased before the comparison!
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func Less(a, b string) int {
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i := 1
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aj := len(a)
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bj := len(b)
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for {
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ai, oka := dns.PrevLabel(a, i)
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bi, okb := dns.PrevLabel(b, i)
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if oka && okb {
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return 0
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}
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// sadly this []byte will allocate... TODO(miek): check if this is needed
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// for a name, otherwise compare the strings.
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ab := []byte(a[ai:aj])
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bb := []byte(b[bi:bj])
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doDDD(ab)
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doDDD(bb)
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res := bytes.Compare(ab, bb)
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if res != 0 {
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return res
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}
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i++
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aj, bj = ai, bi
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}
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return 0
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}
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func doDDD(b []byte) {
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lb := len(b)
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for i := 0; i < lb; i++ {
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if i+3 < lb && b[i] == '\\' && isDigit(b[i+1]) && isDigit(b[i+2]) && isDigit(b[i+3]) {
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b[i] = dddToByte(b[i:])
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for j := i + 1; j < lb-3; j++ {
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b[j] = b[j+3]
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}
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lb -= 3
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}
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}
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}
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func isDigit(b byte) bool { return b >= '0' && b <= '9' }
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func dddToByte(s []byte) byte { return byte((s[1]-'0')*100 + (s[2]-'0')*10 + (s[3] - '0')) }
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