98 lines
2.1 KiB
Go
98 lines
2.1 KiB
Go
package resolver
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import (
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"encoding/json"
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"errors"
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"fmt"
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"log"
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"strings"
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"git.linuxrocker.com/mattburchett/go_tab-magic/pkg/config"
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"git.linuxrocker.com/mattburchett/go_tab-magic/pkg/model"
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"github.com/miekg/dns"
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)
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// LookupName returns IPv4 address from A record or error.
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func lookupName(fqdn, serverAddr string) (string, error) {
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m := &dns.Msg{}
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m.SetQuestion(dns.Fqdn(fqdn), dns.TypeA)
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in, err := dns.Exchange(m, serverAddr)
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if err != nil {
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return "", err
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}
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if len(in.Answer) < 1 {
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return "", errors.New("no Answer")
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}
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if a, ok := in.Answer[0].(*dns.A); ok {
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ip := a.A.String()
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return ip, nil
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}
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return "", errors.New("no A record returned")
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}
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func PerformZoneTransfer(config config.Config) []string {
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data := make([]string, 0)
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// Do the transfer
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for _, i := range config.Domains {
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server := fmt.Sprintf("%s:%d", config.Resolver, config.ResolverPort)
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tr := dns.Transfer{}
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m := &dns.Msg{}
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m.SetAxfr(dns.Fqdn(i))
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in, err := tr.In(m, server)
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if err != nil {
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log.Fatal(err)
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}
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for ex := range in {
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for _, a := range ex.RR {
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var ip, hostname, txt string
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switch v := a.(type) {
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case *dns.TXT:
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txt = string(v.Txt[0])
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hostname = v.Hdr.Name
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cip, err := lookupName(strings.TrimRight(v.Hdr.Name, "."), server)
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if err != nil || cip == "" {
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continue
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}
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ip = cip
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case *dns.A:
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ip = v.A.String()
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hostname = v.Hdr.Name
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case *dns.CNAME:
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cip, err := lookupName(v.Target, server)
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if err != nil || cip == "" {
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continue
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}
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ip = cip
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hostname = v.Hdr.Name
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default:
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continue
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}
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data = append(data, fmt.Sprintf("%v %v %v", strings.TrimRight(hostname, "."), ip, txt))
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}
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}
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}
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// fmt.Println(data)
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// resultsToJSON(data)
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return data
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}
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func resultsToJSON(data []string) {
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jsonData := make([][]byte, 0)
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for _, i := range data {
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splitStrings := strings.Split(i, " ")
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hostname := splitStrings[0]
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ip := splitStrings[1]
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txt := splitStrings[2]
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dns := &model.Results{IP: ip, Hostname: hostname, TXT: txt}
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b, err := json.Marshal(dns)
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if err != nil {
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fmt.Println(err)
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}
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jsonData = append(jsonData, b)
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}
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}
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