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|
package utils
import (
"fmt"
"strconv"
"strings"
"time"
"github.com/miekg/dns"
)
type WrongAnswerError struct {
Message string
}
func (e *WrongAnswerError) Error() string {
return fmt.Sprintf("Wrong Answer: %s", e.Message)
}
func SendQuery(addr string, dn string) (string, error) {
var (
domain string
rdns_ip string
)
if dn == "timestamp" {
timestamp := strconv.FormatInt(time.Now().UnixNano(), 10)
domain = strings.Join([]string{timestamp, "-scan.echodns.xyz."}, "")
} else {
domain = strings.Join([]string{dn, ".echodns.xyz."}, "")
}
//fmt.Println(domain)
m := new(dns.Msg)
m.SetQuestion(domain, dns.TypeA)
m.RecursionDesired = true
res, err := dns.Exchange(m, addr)
if err == nil {
if len(res.Answer) == 1 {
if a, ok := res.Answer[0].(*dns.A); ok {
rdns_ip = a.A.String()
} else {
rdns_ip = ""
err = &WrongAnswerError{
Message: "Wrong Record Type",
}
}
} else {
rdns_ip = ""
err = &WrongAnswerError{
Message: "Wrong Answer Section",
}
}
}
return rdns_ip, err
}
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