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