// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package net
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import (
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"bytes"
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"encoding/json"
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"errors"
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"internal/testenv"
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"os/exec"
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"reflect"
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"regexp"
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"sort"
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"strings"
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"testing"
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)
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var nslookupTestServers = []string{"mail.golang.com", "gmail.com"}
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func toJson(v interface{}) string {
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data, _ := json.Marshal(v)
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return string(data)
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}
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func TestNSLookupMX(t *testing.T) {
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testenv.MustHaveExternalNetwork(t)
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for _, server := range nslookupTestServers {
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mx, err := LookupMX(server)
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if err != nil {
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t.Error(err)
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continue
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}
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if len(mx) == 0 {
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t.Errorf("no results")
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continue
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}
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expected, err := nslookupMX(server)
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if err != nil {
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t.Logf("skipping failed nslookup %s test: %s", server, err)
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}
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sort.Sort(byPrefAndHost(expected))
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sort.Sort(byPrefAndHost(mx))
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if !reflect.DeepEqual(expected, mx) {
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t.Errorf("different results %s:\texp:%v\tgot:%v", server, toJson(expected), toJson(mx))
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}
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}
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}
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func TestNSLookupCNAME(t *testing.T) {
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testenv.MustHaveExternalNetwork(t)
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for _, server := range nslookupTestServers {
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cname, err := LookupCNAME(server)
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if err != nil {
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t.Errorf("failed %s: %s", server, err)
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continue
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}
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if cname == "" {
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t.Errorf("no result %s", server)
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}
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expected, err := nslookupCNAME(server)
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if err != nil {
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t.Logf("skipping failed nslookup %s test: %s", server, err)
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continue
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}
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if expected != cname {
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t.Errorf("different results %s:\texp:%v\tgot:%v", server, expected, cname)
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}
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}
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}
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func TestNSLookupNS(t *testing.T) {
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testenv.MustHaveExternalNetwork(t)
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for _, server := range nslookupTestServers {
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ns, err := LookupNS(server)
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if err != nil {
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t.Errorf("failed %s: %s", server, err)
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continue
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}
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if len(ns) == 0 {
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t.Errorf("no results")
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continue
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}
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expected, err := nslookupNS(server)
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if err != nil {
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t.Logf("skipping failed nslookup %s test: %s", server, err)
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continue
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}
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sort.Sort(byHost(expected))
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sort.Sort(byHost(ns))
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if !reflect.DeepEqual(expected, ns) {
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t.Errorf("different results %s:\texp:%v\tgot:%v", toJson(server), toJson(expected), ns)
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}
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}
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}
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func TestNSLookupTXT(t *testing.T) {
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testenv.MustHaveExternalNetwork(t)
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for _, server := range nslookupTestServers {
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txt, err := LookupTXT(server)
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if err != nil {
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t.Errorf("failed %s: %s", server, err)
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continue
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}
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if len(txt) == 0 {
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t.Errorf("no results")
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continue
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}
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expected, err := nslookupTXT(server)
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if err != nil {
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t.Logf("skipping failed nslookup %s test: %s", server, err)
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continue
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}
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sort.Strings(expected)
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sort.Strings(txt)
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if !reflect.DeepEqual(expected, txt) {
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t.Errorf("different results %s:\texp:%v\tgot:%v", server, toJson(expected), toJson(txt))
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}
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}
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}
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type byPrefAndHost []*MX
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func (s byPrefAndHost) Len() int { return len(s) }
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func (s byPrefAndHost) Less(i, j int) bool {
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if s[i].Pref != s[j].Pref {
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return s[i].Pref < s[j].Pref
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}
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return s[i].Host < s[j].Host
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}
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func (s byPrefAndHost) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
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type byHost []*NS
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func (s byHost) Len() int { return len(s) }
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func (s byHost) Less(i, j int) bool { return s[i].Host < s[j].Host }
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func (s byHost) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
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func nslookup(qtype, name string) (string, error) {
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var out bytes.Buffer
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var err bytes.Buffer
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cmd := exec.Command("nslookup", "-querytype="+qtype, name)
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cmd.Stdout = &out
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cmd.Stderr = &err
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if err := cmd.Run(); err != nil {
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return "", err
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}
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r := strings.ReplaceAll(out.String(), "\r\n", "\n")
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// nslookup stderr output contains also debug information such as
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// "Non-authoritative answer" and it doesn't return the correct errcode
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if strings.Contains(err.String(), "can't find") {
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return r, errors.New(err.String())
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}
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return r, nil
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}
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func nslookupMX(name string) (mx []*MX, err error) {
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var r string
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if r, err = nslookup("mx", name); err != nil {
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return
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}
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mx = make([]*MX, 0, 10)
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// linux nslookup syntax
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// golang.org mail exchanger = 2 alt1.aspmx.l.google.com.
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rx := regexp.MustCompile(`(?m)^([a-z0-9.\-]+)\s+mail exchanger\s*=\s*([0-9]+)\s*([a-z0-9.\-]+)$`)
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for _, ans := range rx.FindAllStringSubmatch(r, -1) {
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pref, _, _ := dtoi(ans[2])
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mx = append(mx, &MX{absDomainName([]byte(ans[3])), uint16(pref)})
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}
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// windows nslookup syntax
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// gmail.com MX preference = 30, mail exchanger = alt3.gmail-smtp-in.l.google.com
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rx = regexp.MustCompile(`(?m)^([a-z0-9.\-]+)\s+MX preference\s*=\s*([0-9]+)\s*,\s*mail exchanger\s*=\s*([a-z0-9.\-]+)$`)
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for _, ans := range rx.FindAllStringSubmatch(r, -1) {
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pref, _, _ := dtoi(ans[2])
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mx = append(mx, &MX{absDomainName([]byte(ans[3])), uint16(pref)})
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}
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return
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}
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func nslookupNS(name string) (ns []*NS, err error) {
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var r string
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if r, err = nslookup("ns", name); err != nil {
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return
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}
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ns = make([]*NS, 0, 10)
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// golang.org nameserver = ns1.google.com.
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rx := regexp.MustCompile(`(?m)^([a-z0-9.\-]+)\s+nameserver\s*=\s*([a-z0-9.\-]+)$`)
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for _, ans := range rx.FindAllStringSubmatch(r, -1) {
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ns = append(ns, &NS{absDomainName([]byte(ans[2]))})
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}
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return
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}
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func nslookupCNAME(name string) (cname string, err error) {
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var r string
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if r, err = nslookup("cname", name); err != nil {
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return
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}
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// mail.golang.com canonical name = golang.org.
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rx := regexp.MustCompile(`(?m)^([a-z0-9.\-]+)\s+canonical name\s*=\s*([a-z0-9.\-]+)$`)
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// assumes the last CNAME is the correct one
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last := name
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for _, ans := range rx.FindAllStringSubmatch(r, -1) {
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last = ans[2]
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}
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return absDomainName([]byte(last)), nil
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}
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func nslookupTXT(name string) (txt []string, err error) {
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var r string
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if r, err = nslookup("txt", name); err != nil {
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return
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}
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txt = make([]string, 0, 10)
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// linux
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// golang.org text = "v=spf1 redirect=_spf.google.com"
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// windows
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// golang.org text =
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//
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// "v=spf1 redirect=_spf.google.com"
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rx := regexp.MustCompile(`(?m)^([a-z0-9.\-]+)\s+text\s*=\s*"(.*)"$`)
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for _, ans := range rx.FindAllStringSubmatch(r, -1) {
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txt = append(txt, ans[2])
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}
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return
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}
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