Golang程序
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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 (
"fmt"
"io/ioutil"
"os"
"path"
"reflect"
"strings"
"sync"
"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("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 resolution APIs and libraries should not recognize the
// followings as special.
{"1.0.168.192.in-addr.arpa.", dnsTypePTR, dnsRcodeNameError},
{"test.", dnsTypeALL, dnsRcodeNameError},
{"example.com.", dnsTypeALL, dnsRcodeSuccess},
// Name resolution APIs and libraries should recognize 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("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 {
dir string
path string
*resolverConfig
}
func newResolvConfTest() (*resolvConfTest, error) {
dir, err := ioutil.TempDir("", "go-resolvconftest")
if err != nil {
return nil, err
}
conf := &resolvConfTest{
dir: dir,
path: path.Join(dir, "resolv.conf"),
resolverConfig: &resolvConf,
}
conf.initOnce.Do(conf.init)
return conf, nil
}
func (conf *resolvConfTest) writeAndUpdate(lines []string) error {
f, err := os.OpenFile(conf.path, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0600)
if err != nil {
return err
}
if _, err := f.WriteString(strings.Join(lines, "\n")); err != nil {
f.Close()
return err
}
f.Close()
if err := conf.forceUpdate(conf.path); err != nil {
return err
}
return nil
}
func (conf *resolvConfTest) forceUpdate(name string) error {
dnsConf := dnsReadConfig(name)
conf.mu.Lock()
conf.dnsConfig = dnsConf
conf.mu.Unlock()
for i := 0; i < 5; i++ {
if conf.tryAcquireSema() {
conf.lastChecked = time.Time{}
conf.releaseSema()
return nil
}
}
return fmt.Errorf("tryAcquireSema for %s failed", name)
}
func (conf *resolvConfTest) servers() []string {
conf.mu.RLock()
servers := conf.dnsConfig.servers
conf.mu.RUnlock()
return servers
}
func (conf *resolvConfTest) teardown() error {
err := conf.forceUpdate("/etc/resolv.conf")
os.RemoveAll(conf.dir)
return err
}
var updateResolvConfTests = []struct {
name string // query name
lines []string // resolver configuration lines
servers []string // expected name servers
}{
{
name: "golang.org",
lines: []string{"nameserver 8.8.8.8"},
servers: []string{"8.8.8.8"},
},
{
name: "",
lines: nil, // an empty resolv.conf should use defaultNS as name servers
servers: defaultNS,
},
{
name: "www.example.com",
lines: []string{"nameserver 8.8.4.4"},
servers: []string{"8.8.4.4"},
},
}
func TestUpdateResolvConf(t *testing.T) {
if testing.Short() || !*testExternal {
t.Skip("avoid external network")
}
conf, err := newResolvConfTest()
if err != nil {
t.Fatal(err)
}
defer conf.teardown()
for i, tt := range updateResolvConfTests {
if err := conf.writeAndUpdate(tt.lines); err != nil {
t.Error(err)
continue
}
if tt.name != "" {
var wg sync.WaitGroup
const N = 10
wg.Add(N)
for j := 0; j < N; j++ {
go func(name string) {
defer wg.Done()
ips, err := goLookupIP(name)
if err != nil {
t.Error(err)
return
}
if len(ips) == 0 {
t.Errorf("no records for %s", name)
return
}
}(tt.name)
}
wg.Wait()
}
servers := conf.servers()
if !reflect.DeepEqual(servers, tt.servers) {
t.Errorf("#%d: got %v; want %v", i, servers, tt.servers)
continue
}
}
}
var goLookupIPWithResolverConfigTests = []struct {
name string
lines []string // resolver configuration lines
error
a, aaaa bool // whether response contains A, AAAA-record
}{
// no records, transport timeout
{
"jgahvsekduiv9bw4b3qhn4ykdfgj0493iohkrjfhdvhjiu4j",
[]string{
"options timeout:1 attempts:1",
"nameserver 255.255.255.255", // please forgive us for abuse of limited broadcast address
},
&DNSError{Name: "jgahvsekduiv9bw4b3qhn4ykdfgj0493iohkrjfhdvhjiu4j", Server: "255.255.255.255:53", IsTimeout: true},
false, false,
},
// no records, non-existent domain
{
"jgahvsekduiv9bw4b3qhn4ykdfgj0493iohkrjfhdvhjiu4j",
[]string{
"options timeout:3 attempts:1",
"nameserver 8.8.8.8",
},
&DNSError{Name: "jgahvsekduiv9bw4b3qhn4ykdfgj0493iohkrjfhdvhjiu4j", Server: "8.8.8.8:53", IsTimeout: false},
false, false,
},
// a few A records, no AAAA records
{
"ipv4.google.com.",
[]string{
"nameserver 8.8.8.8",
"nameserver 2001:4860:4860::8888",
},
nil,
true, false,
},
{
"ipv4.google.com",
[]string{
"domain golang.org",
"nameserver 2001:4860:4860::8888",
"nameserver 8.8.8.8",
},
nil,
true, false,
},
{
"ipv4.google.com",
[]string{
"search x.golang.org y.golang.org",
"nameserver 2001:4860:4860::8888",
"nameserver 8.8.8.8",
},
nil,
true, false,
},
// no A records, a few AAAA records
{
"ipv6.google.com.",
[]string{
"nameserver 2001:4860:4860::8888",
"nameserver 8.8.8.8",
},
nil,
false, true,
},
{
"ipv6.google.com",
[]string{
"domain golang.org",
"nameserver 8.8.8.8",
"nameserver 2001:4860:4860::8888",
},
nil,
false, true,
},
{
"ipv6.google.com",
[]string{
"search x.golang.org y.golang.org",
"nameserver 8.8.8.8",
"nameserver 2001:4860:4860::8888",
},
nil,
false, true,
},
// both A and AAAA records
{
"hostname.as112.net", // see RFC 7534
[]string{
"domain golang.org",
"nameserver 2001:4860:4860::8888",
"nameserver 8.8.8.8",
},
nil,
true, true,
},
{
"hostname.as112.net", // see RFC 7534
[]string{
"search x.golang.org y.golang.org",
"nameserver 2001:4860:4860::8888",
"nameserver 8.8.8.8",
},
nil,
true, true,
},
}
func TestGoLookupIPWithResolverConfig(t *testing.T) {
if testing.Short() || !*testExternal {
t.Skip("avoid external network")
}
conf, err := newResolvConfTest()
if err != nil {
t.Fatal(err)
}
defer conf.teardown()
for _, tt := range goLookupIPWithResolverConfigTests {
if err := conf.writeAndUpdate(tt.lines); err != nil {
t.Error(err)
continue
}
conf.tryUpdate(conf.path)
addrs, err := goLookupIP(tt.name)
if err != nil {
if err, ok := err.(*DNSError); !ok || (err.Name != tt.error.(*DNSError).Name || err.Server != tt.error.(*DNSError).Server || err.IsTimeout != tt.error.(*DNSError).IsTimeout) {
t.Errorf("got %v; want %v", err, tt.error)
}
continue
}
if len(addrs) == 0 {
t.Errorf("no records for %s", tt.name)
}
if !tt.a && !tt.aaaa && len(addrs) > 0 {
t.Errorf("unexpected %v for %s", addrs, tt.name)
}
for _, addr := range addrs {
if !tt.a && addr.IP.To4() != nil {
t.Errorf("got %v; must not be IPv4 address", addr)
}
if !tt.aaaa && addr.IP.To16() != nil && addr.IP.To4() == nil {
t.Errorf("got %v; must not be IPv6 address", addr)
}
}
}
}
func BenchmarkGoLookupIP(b *testing.B) {
testHookUninstaller.Do(uninstallTestHooks)
for i := 0; i < b.N; i++ {
goLookupIP("www.example.com")
}
}
func BenchmarkGoLookupIPNoSuchHost(b *testing.B) {
testHookUninstaller.Do(uninstallTestHooks)
for i := 0; i < b.N; i++ {
goLookupIP("some.nonexistent")
}
}
func BenchmarkGoLookupIPWithBrokenNameServer(b *testing.B) {
testHookUninstaller.Do(uninstallTestHooks)
conf, err := newResolvConfTest()
if err != nil {
b.Fatal(err)
}
defer conf.teardown()
lines := []string{
"nameserver 203.0.113.254", // use TEST-NET-3 block, see RFC 5737
"nameserver 8.8.8.8",
}
if err := conf.writeAndUpdate(lines); err != nil {
b.Fatal(err)
}
for i := 0; i < b.N; i++ {
goLookupIP("www.example.com")
}
}