dns/nsec3.go

60 lines
1.3 KiB
Go

package dns
import (
"io"
"hash"
"strings"
"crypto/sha1"
)
type saltWireFmt struct {
Salt string "size-hex"
}
// HashName hashes a string or label according to RFC5155. It returns
// the hashed string.
func HashName(label string, ha int, iterations int, salt string) string {
saltwire := new(saltWireFmt)
saltwire.Salt = salt
wire := make([]byte, DefaultMsgSize)
n, ok := packStruct(saltwire, wire, 0)
if !ok {
return ""
}
wire = wire[:n]
name := make([]byte, 255)
off, ok1 := packDomainName(strings.ToLower(label), name, 0)
if !ok1 {
return ""
}
name = name[:off]
var s hash.Hash
switch ha {
case SHA1:
s = sha1.New()
default:
return ""
}
// k = 0
name = append(name, wire...)
io.WriteString(s, string(name))
nsec3 := s.Sum()
// k > 0
for k := 0; k < iterations; k++ {
s.Reset()
nsec3 = append(nsec3, wire...)
io.WriteString(s, string(nsec3))
nsec3 = s.Sum()
}
return unpackBase32(nsec3)
}
// Hash the ownername and the next owner name in an NSEC3 record according
// to RFC 5155.
// Use the parameters from the NSEC3 itself.
func (nsec3 *RR_NSEC3) HashNames() {
nsec3.Header().Name = hashName(nsec3.Header().Name, int(nsec3.Hash), int(nsec3.Iterations), nsec3.Salt)
nsec3.NextDomain = hashName(nsec3.NextDomain, int(nsec3.Hash), int(nsec3.Iterations), nsec3.Salt)
}