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// Copyright 2013 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.
// +build darwin dragonfly freebsd linux netbsd openbsd solaris
package net
import (
"io"
"io/ioutil"
"os"
"path"
"reflect"
"testing"
"time"
)
var dnsTransportFallbackTests = []struct {
server string
name string
qtype uint16
timeout int
rcode int
}{
// Querying "com." with qtype=255 usually makes an answer
// which requires more than 512 bytes.
{"8.8.8.8:53", "com.", dnsTypeALL, 2, dnsRcodeSuccess},
{"8.8.4.4:53", "com.", dnsTypeALL, 4, dnsRcodeSuccess},
}
func TestDNSTransportFallback(t *testing.T) {
if testing.Short() || !*testExternal {
t.Skip("skipping test to avoid external network")
}
for _, tt := range dnsTransportFallbackTests {
timeout := time.Duration(tt.timeout) * time.Second
msg, err := exchange(tt.server, tt.name, tt.qtype, timeout)
if err != nil {
t.Error(err)
continue
}
switch msg.rcode {
case tt.rcode, dnsRcodeServerFailure:
default:
t.Errorf("got %v from %v; want %v", msg.rcode, tt.server, tt.rcode)
continue
}
}
}
// See RFC 6761 for further information about the reserved, pseudo
// domain names.
var specialDomainNameTests = []struct {
name string
qtype uint16
rcode int
}{
// Name resoltion APIs and libraries should not recongnize the
// followings as special.
{"1.0.168.192.in-addr.arpa.", dnsTypePTR, dnsRcodeNameError},
{"test.", dnsTypeALL, dnsRcodeNameError},
{"example.com.", dnsTypeALL, dnsRcodeSuccess},
// Name resoltion APIs and libraries should recongnize the
// followings as special and should not send any queries.
// Though, we test those names here for verifying nagative
// answers at DNS query-response interaction level.
{"localhost.", dnsTypeALL, dnsRcodeNameError},
{"invalid.", dnsTypeALL, dnsRcodeNameError},
}
func TestSpecialDomainName(t *testing.T) {
if testing.Short() || !*testExternal {
t.Skip("skipping test to avoid external network")
}
server := "8.8.8.8:53"
for _, tt := range specialDomainNameTests {
msg, err := exchange(server, tt.name, tt.qtype, 0)
if err != nil {
t.Error(err)
continue
}
switch msg.rcode {
case tt.rcode, dnsRcodeServerFailure:
default:
t.Errorf("got %v from %v; want %v", msg.rcode, server, tt.rcode)
continue
}
}
}
type resolvConfTest struct {
*testing.T
dir string
path string
started bool
quitc chan chan struct{}
}
func newResolvConfTest(t *testing.T) *resolvConfTest {
dir, err := ioutil.TempDir("", "resolvConfTest")
if err != nil {
t.Fatalf("could not create temp dir: %v", err)
}
// Disable the default loadConfig
onceLoadConfig.Do(func() {})
r := &resolvConfTest{
T: t,
dir: dir,
path: path.Join(dir, "resolv.conf"),
quitc: make(chan chan struct{}),
}
return r
}
func (r *resolvConfTest) Start() {
loadConfig(r.path, 100*time.Millisecond, r.quitc)
r.started = true
}
func (r *resolvConfTest) SetConf(s string) {
// Make sure the file mtime will be different once we're done here,
// even on systems with coarse (1s) mtime resolution.
time.Sleep(time.Second)
f, err := os.OpenFile(r.path, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0600)
if err != nil {
r.Fatalf("failed to create temp file %s: %v", r.path, err)
}
if _, err := io.WriteString(f, s); err != nil {
f.Close()
r.Fatalf("failed to write temp file: %v", err)
}
f.Close()
if r.started {
cfg.ch <- struct{}{} // fill buffer
cfg.ch <- struct{}{} // wait for reload to begin
cfg.ch <- struct{}{} // wait for reload to complete
}
}
func (r *resolvConfTest) WantServers(want []string) {
cfg.mu.RLock()
defer cfg.mu.RUnlock()
if got := cfg.dnsConfig.servers; !reflect.DeepEqual(got, want) {
r.Fatalf("Unexpected dns server loaded, got %v want %v", got, want)
}
}
func (r *resolvConfTest) Close() {
resp := make(chan struct{})
r.quitc <- resp
<-resp
if err := os.RemoveAll(r.dir); err != nil {
r.Logf("failed to remove temp dir %s: %v", r.dir, err)
}
}
func TestReloadResolvConfFail(t *testing.T) {
if testing.Short() || !*testExternal {
t.Skip("skipping test to avoid external network")
}
r := newResolvConfTest(t)
defer r.Close()
// resolv.conf.tmp does not exist yet
r.Start()
if _, err := goLookupIP("golang.org"); err == nil {
t.Fatal("goLookupIP(missing) succeeded")
}
r.SetConf("nameserver 8.8.8.8")
if _, err := goLookupIP("golang.org"); err != nil {
t.Fatalf("goLookupIP(missing; good) failed: %v", err)
}
// Using a bad resolv.conf while we had a good
// one before should not update the config
r.SetConf("")
if _, err := goLookupIP("golang.org"); err != nil {
t.Fatalf("goLookupIP(missing; good; bad) failed: %v", err)
}
}
func TestReloadResolvConfChange(t *testing.T) {
if testing.Short() || !*testExternal {
t.Skip("skipping test to avoid external network")
}
r := newResolvConfTest(t)
defer r.Close()
r.SetConf("nameserver 8.8.8.8")
r.Start()
if _, err := goLookupIP("golang.org"); err != nil {
t.Fatalf("goLookupIP(good) failed: %v", err)
}
r.WantServers([]string{"8.8.8.8"})
// Using a bad resolv.conf when we had a good one
// before should not update the config
r.SetConf("")
if _, err := goLookupIP("golang.org"); err != nil {
t.Fatalf("goLookupIP(good; bad) failed: %v", err)
}
// A new good config should get picked up
r.SetConf("nameserver 8.8.4.4")
r.WantServers([]string{"8.8.4.4"})
}
func BenchmarkGoLookupIP(b *testing.B) {
for i := 0; i < b.N; i++ {
goLookupIP("www.example.com")
}
}
func BenchmarkGoLookupIPNoSuchHost(b *testing.B) {
for i := 0; i < b.N; i++ {
goLookupIP("some.nonexistent")
}
}
func BenchmarkGoLookupIPWithBrokenNameServer(b *testing.B) {
onceLoadConfig.Do(loadDefaultConfig)
if cfg.dnserr != nil || cfg.dnsConfig == nil {
b.Fatalf("loadConfig failed: %v", cfg.dnserr)
}
// This looks ugly but it's safe as long as benchmarks are run
// sequentially in package testing.
orig := cfg.dnsConfig
cfg.dnsConfig.servers = append([]string{"203.0.113.254"}, cfg.dnsConfig.servers...) // use TEST-NET-3 block, see RFC 5737
for i := 0; i < b.N; i++ {
goLookupIP("www.example.com")
}
cfg.dnsConfig = orig
}
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