90 lines
1.8 KiB
Go
90 lines
1.8 KiB
Go
package dns
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import (
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"fmt"
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"github.com/miekg/dns"
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"net"
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"slices"
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"strings"
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)
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type Domain struct {
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Name string
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NS []string
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}
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func CheckDomain(d, tld string) Domain {
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nameservers := []string{}
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fqdn := fmt.Sprintf("%v.%v", d, tld)
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tldServers, err := getNameserverForTLD(tld)
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if err != nil {
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return Domain{fqdn, nameservers}
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}
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for _, tldServer := range tldServers {
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nameservers, err = queryTLDNamserver(fqdn, tldServer)
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if err == nil {
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break
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}
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}
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if err != nil {
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return Domain{
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Name: fqdn,
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NS: nameservers,
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}
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}
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slices.Sort(nameservers)
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return Domain{
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Name: fqdn,
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NS: nameservers,
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}
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}
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func getNameserverForTLD(tld string) ([]string, error) {
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ns, err := net.LookupNS(tld)
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if err != nil {
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return nil, err
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}
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var tldServer []string
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if len(ns) > 0 {
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for _, n := range ns {
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tldServer = append(tldServer, strings.Trim(n.Host, ".")+":53")
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}
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} else {
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return nil, fmt.Errorf("no nameserver found for TLD %v", tld)
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}
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return tldServer, nil
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}
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func queryTLDNamserver(fqdn, tldServer string) ([]string, error) {
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// Create a new DNS message
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m := new(dns.Msg)
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// Set the question section of the message with the fqdn and query type
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m.SetQuestion(dns.Fqdn(fqdn), dns.TypeNS)
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// Create a DNS client
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c := new(dns.Client)
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// Send the DNS query to the TLD server
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r, _, err := c.Exchange(m, tldServer)
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if err != nil {
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return nil, fmt.Errorf("dns query error: %v", err)
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}
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// Check for response errors
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if r.Rcode != dns.RcodeSuccess {
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return nil, fmt.Errorf("failed to get a valid response for %v: %v", fqdn, r.Rcode)
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}
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// Print the nameservers from the response
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nameservers := []string{}
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for _, ans := range r.Ns {
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if ns, ok := ans.(*dns.NS); ok {
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nameservers = append(nameservers, strings.ToLower(ns.Ns))
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}
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}
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return nameservers, nil
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}
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