35 lines
756 B
Go
35 lines
756 B
Go
|
package dnsxl
|
||
|
|
|
||
|
|
import (
|
||
|
|
"net"
|
||
|
|
"strconv"
|
||
|
|
"strings"
|
||
|
|
)
|
||
|
|
|
||
|
|
// reverseName converts an IPv4 or IPv6 address into the reversed name
|
||
|
|
// notation as described in RFC 1034 (for IPv4) or RFC 3596 (for IPv6).
|
||
|
|
func reverseName(ip net.IP) string {
|
||
|
|
const hexdig = "0123456789abcdef"
|
||
|
|
var b strings.Builder
|
||
|
|
if ip4 := ip.To4(); ip4 != nil {
|
||
|
|
b.WriteString(strconv.Itoa(int(ip4[3])))
|
||
|
|
b.WriteByte('.')
|
||
|
|
b.WriteString(strconv.Itoa(int(ip4[2])))
|
||
|
|
b.WriteByte('.')
|
||
|
|
b.WriteString(strconv.Itoa(int(ip4[1])))
|
||
|
|
b.WriteByte('.')
|
||
|
|
b.WriteString(strconv.Itoa(int(ip4[0])))
|
||
|
|
} else {
|
||
|
|
for i := 15; i >= 0; i-- {
|
||
|
|
x := ip[i]
|
||
|
|
b.WriteByte(hexdig[x&15])
|
||
|
|
b.WriteByte('.')
|
||
|
|
b.WriteByte(hexdig[x>>4])
|
||
|
|
if i > 0 {
|
||
|
|
b.WriteByte('.')
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return b.String()
|
||
|
|
}
|