53 lines
998 B
Go
53 lines
998 B
Go
package dns
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import (
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"io"
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"hash"
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"strings"
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"crypto/sha1"
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)
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type saltWireFmt struct {
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Salt string "size-hex"
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}
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// Hash a string/label according to RFC5155
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func Nsec3Hash(label string, ha int, iterations int, salt string) string {
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saltwire := new(saltWireFmt)
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saltwire.Salt = salt
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wire := make([]byte, DefaultMsgSize)
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n, ok := packStruct(saltwire, wire, 0)
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if !ok {
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return ""
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}
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wire = wire[:n]
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name := make([]byte, 255)
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off, ok1 := packDomainName(strings.ToLower(label), name, 0)
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if !ok1 {
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return ""
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}
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name = name[:off]
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var s hash.Hash
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switch ha {
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case HashSHA1:
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s = sha1.New()
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default:
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return ""
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}
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// k = 0
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name = append(name, wire...)
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io.WriteString(s, string(name))
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nsec3 := s.Sum()
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// k > 0
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for k := 0; k < iterations; k++ {
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s.Reset()
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nsec3 = append(nsec3, wire...)
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io.WriteString(s, string(nsec3))
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nsec3 = s.Sum()
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}
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return unpackBase32(nsec3)
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}
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