1315 lines
30 KiB
Go
1315 lines
30 KiB
Go
// Copyright 2013 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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// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
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package net
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import (
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"context"
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"errors"
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"fmt"
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"internal/poll"
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"io/ioutil"
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"os"
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"path"
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"reflect"
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"strings"
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"sync"
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"testing"
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"time"
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)
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var goResolver = Resolver{PreferGo: true}
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// Test address from 192.0.2.0/24 block, reserved by RFC 5737 for documentation.
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const TestAddr uint32 = 0xc0000201
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// Test address from 2001:db8::/32 block, reserved by RFC 3849 for documentation.
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var TestAddr6 = [16]byte{0x20, 0x01, 0x0d, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
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var dnsTransportFallbackTests = []struct {
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server string
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name string
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qtype uint16
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timeout int
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rcode int
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}{
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// Querying "com." with qtype=255 usually makes an answer
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// which requires more than 512 bytes.
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{"8.8.8.8:53", "com.", dnsTypeALL, 2, dnsRcodeSuccess},
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{"8.8.4.4:53", "com.", dnsTypeALL, 4, dnsRcodeSuccess},
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}
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func TestDNSTransportFallback(t *testing.T) {
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fake := fakeDNSServer{
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rh: func(n, _ string, q *dnsMsg, _ time.Time) (*dnsMsg, error) {
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r := &dnsMsg{
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dnsMsgHdr: dnsMsgHdr{
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id: q.id,
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response: true,
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rcode: dnsRcodeSuccess,
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},
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question: q.question,
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}
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if n == "udp" {
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r.truncated = true
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}
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return r, nil
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},
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}
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r := Resolver{PreferGo: true, Dial: fake.DialContext}
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for _, tt := range dnsTransportFallbackTests {
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ctx, cancel := context.WithCancel(context.Background())
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defer cancel()
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msg, err := r.exchange(ctx, tt.server, tt.name, tt.qtype, time.Second)
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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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switch msg.rcode {
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case tt.rcode:
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default:
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t.Errorf("got %v from %v; want %v", msg.rcode, tt.server, tt.rcode)
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continue
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}
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}
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}
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// See RFC 6761 for further information about the reserved, pseudo
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// domain names.
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var specialDomainNameTests = []struct {
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name string
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qtype uint16
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rcode int
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}{
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// Name resolution APIs and libraries should not recognize the
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// followings as special.
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{"1.0.168.192.in-addr.arpa.", dnsTypePTR, dnsRcodeNameError},
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{"test.", dnsTypeALL, dnsRcodeNameError},
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{"example.com.", dnsTypeALL, dnsRcodeSuccess},
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// Name resolution APIs and libraries should recognize the
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// followings as special and should not send any queries.
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// Though, we test those names here for verifying negative
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// answers at DNS query-response interaction level.
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{"localhost.", dnsTypeALL, dnsRcodeNameError},
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{"invalid.", dnsTypeALL, dnsRcodeNameError},
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}
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func TestSpecialDomainName(t *testing.T) {
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fake := fakeDNSServer{func(_, _ string, q *dnsMsg, _ time.Time) (*dnsMsg, error) {
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r := &dnsMsg{
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dnsMsgHdr: dnsMsgHdr{
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id: q.id,
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response: true,
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},
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question: q.question,
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}
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switch q.question[0].Name {
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case "example.com.":
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r.rcode = dnsRcodeSuccess
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default:
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r.rcode = dnsRcodeNameError
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}
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return r, nil
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}}
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r := Resolver{PreferGo: true, Dial: fake.DialContext}
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server := "8.8.8.8:53"
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for _, tt := range specialDomainNameTests {
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ctx, cancel := context.WithCancel(context.Background())
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defer cancel()
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msg, err := r.exchange(ctx, server, tt.name, tt.qtype, 3*time.Second)
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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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switch msg.rcode {
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case tt.rcode, dnsRcodeServerFailure:
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default:
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t.Errorf("got %v from %v; want %v", msg.rcode, server, tt.rcode)
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continue
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}
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}
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}
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// Issue 13705: don't try to resolve onion addresses, etc
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func TestAvoidDNSName(t *testing.T) {
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tests := []struct {
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name string
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avoid bool
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}{
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{"foo.com", false},
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{"foo.com.", false},
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{"foo.onion.", true},
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{"foo.onion", true},
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{"foo.ONION", true},
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{"foo.ONION.", true},
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// But do resolve *.local address; Issue 16739
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{"foo.local.", false},
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{"foo.local", false},
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{"foo.LOCAL", false},
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{"foo.LOCAL.", false},
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{"", true}, // will be rejected earlier too
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// Without stuff before onion/local, they're fine to
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// use DNS. With a search path,
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// "onion.vegegtables.com" can use DNS. Without a
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// search path (or with a trailing dot), the queries
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// are just kinda useless, but don't reveal anything
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// private.
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{"local", false},
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{"onion", false},
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{"local.", false},
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{"onion.", false},
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}
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for _, tt := range tests {
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got := avoidDNS(tt.name)
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if got != tt.avoid {
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t.Errorf("avoidDNS(%q) = %v; want %v", tt.name, got, tt.avoid)
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}
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}
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}
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var fakeDNSServerSuccessful = fakeDNSServer{func(_, _ string, q *dnsMsg, _ time.Time) (*dnsMsg, error) {
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r := &dnsMsg{
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dnsMsgHdr: dnsMsgHdr{
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id: q.id,
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response: true,
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},
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question: q.question,
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}
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if len(q.question) == 1 && q.question[0].Qtype == dnsTypeA {
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r.answer = []dnsRR{
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&dnsRR_A{
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Hdr: dnsRR_Header{
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Name: q.question[0].Name,
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Rrtype: dnsTypeA,
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Class: dnsClassINET,
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Rdlength: 4,
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},
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A: TestAddr,
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},
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}
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}
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return r, nil
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}}
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// Issue 13705: don't try to resolve onion addresses, etc
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func TestLookupTorOnion(t *testing.T) {
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r := Resolver{PreferGo: true, Dial: fakeDNSServerSuccessful.DialContext}
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addrs, err := r.LookupIPAddr(context.Background(), "foo.onion")
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if err != nil {
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t.Fatalf("lookup = %v; want nil", err)
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}
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if len(addrs) > 0 {
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t.Errorf("unexpected addresses: %v", addrs)
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}
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}
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type resolvConfTest struct {
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dir string
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path string
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*resolverConfig
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}
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func newResolvConfTest() (*resolvConfTest, error) {
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dir, err := ioutil.TempDir("", "go-resolvconftest")
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if err != nil {
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return nil, err
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}
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conf := &resolvConfTest{
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dir: dir,
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path: path.Join(dir, "resolv.conf"),
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resolverConfig: &resolvConf,
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}
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conf.initOnce.Do(conf.init)
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return conf, nil
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}
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func (conf *resolvConfTest) writeAndUpdate(lines []string) error {
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f, err := os.OpenFile(conf.path, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0600)
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if err != nil {
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return err
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}
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if _, err := f.WriteString(strings.Join(lines, "\n")); err != nil {
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f.Close()
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return err
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}
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f.Close()
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if err := conf.forceUpdate(conf.path, time.Now().Add(time.Hour)); err != nil {
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return err
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}
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return nil
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}
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func (conf *resolvConfTest) forceUpdate(name string, lastChecked time.Time) error {
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dnsConf := dnsReadConfig(name)
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conf.mu.Lock()
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conf.dnsConfig = dnsConf
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conf.mu.Unlock()
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for i := 0; i < 5; i++ {
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if conf.tryAcquireSema() {
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conf.lastChecked = lastChecked
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conf.releaseSema()
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return nil
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}
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}
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return fmt.Errorf("tryAcquireSema for %s failed", name)
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}
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func (conf *resolvConfTest) servers() []string {
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conf.mu.RLock()
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servers := conf.dnsConfig.servers
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conf.mu.RUnlock()
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return servers
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}
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func (conf *resolvConfTest) teardown() error {
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err := conf.forceUpdate("/etc/resolv.conf", time.Time{})
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os.RemoveAll(conf.dir)
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return err
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}
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var updateResolvConfTests = []struct {
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name string // query name
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lines []string // resolver configuration lines
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servers []string // expected name servers
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}{
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{
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name: "golang.org",
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lines: []string{"nameserver 8.8.8.8"},
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servers: []string{"8.8.8.8:53"},
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},
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{
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name: "",
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lines: nil, // an empty resolv.conf should use defaultNS as name servers
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servers: defaultNS,
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},
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{
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name: "www.example.com",
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lines: []string{"nameserver 8.8.4.4"},
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servers: []string{"8.8.4.4:53"},
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},
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}
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func TestUpdateResolvConf(t *testing.T) {
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r := Resolver{PreferGo: true, Dial: fakeDNSServerSuccessful.DialContext}
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conf, err := newResolvConfTest()
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if err != nil {
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t.Fatal(err)
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}
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defer conf.teardown()
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for i, tt := range updateResolvConfTests {
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if err := conf.writeAndUpdate(tt.lines); err != nil {
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t.Error(err)
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continue
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}
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if tt.name != "" {
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var wg sync.WaitGroup
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const N = 10
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wg.Add(N)
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for j := 0; j < N; j++ {
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go func(name string) {
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defer wg.Done()
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ips, err := r.LookupIPAddr(context.Background(), name)
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if err != nil {
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t.Error(err)
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return
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}
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if len(ips) == 0 {
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t.Errorf("no records for %s", name)
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return
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}
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}(tt.name)
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}
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wg.Wait()
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}
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servers := conf.servers()
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if !reflect.DeepEqual(servers, tt.servers) {
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t.Errorf("#%d: got %v; want %v", i, servers, tt.servers)
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continue
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}
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}
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}
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var goLookupIPWithResolverConfigTests = []struct {
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name string
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lines []string // resolver configuration lines
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error
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a, aaaa bool // whether response contains A, AAAA-record
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}{
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// no records, transport timeout
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{
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"jgahvsekduiv9bw4b3qhn4ykdfgj0493iohkrjfhdvhjiu4j",
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[]string{
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"options timeout:1 attempts:1",
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"nameserver 255.255.255.255", // please forgive us for abuse of limited broadcast address
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},
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&DNSError{Name: "jgahvsekduiv9bw4b3qhn4ykdfgj0493iohkrjfhdvhjiu4j", Server: "255.255.255.255:53", IsTimeout: true},
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false, false,
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},
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// no records, non-existent domain
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{
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"jgahvsekduiv9bw4b3qhn4ykdfgj0493iohkrjfhdvhjiu4j",
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[]string{
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"options timeout:3 attempts:1",
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"nameserver 8.8.8.8",
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},
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&DNSError{Name: "jgahvsekduiv9bw4b3qhn4ykdfgj0493iohkrjfhdvhjiu4j", Server: "8.8.8.8:53", IsTimeout: false},
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false, false,
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},
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// a few A records, no AAAA records
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{
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"ipv4.google.com.",
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[]string{
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"nameserver 8.8.8.8",
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"nameserver 2001:4860:4860::8888",
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},
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nil,
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true, false,
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},
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{
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"ipv4.google.com",
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[]string{
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"domain golang.org",
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"nameserver 2001:4860:4860::8888",
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"nameserver 8.8.8.8",
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},
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nil,
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true, false,
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},
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{
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"ipv4.google.com",
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[]string{
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"search x.golang.org y.golang.org",
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"nameserver 2001:4860:4860::8888",
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"nameserver 8.8.8.8",
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},
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nil,
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true, false,
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},
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// no A records, a few AAAA records
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{
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"ipv6.google.com.",
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[]string{
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"nameserver 2001:4860:4860::8888",
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"nameserver 8.8.8.8",
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},
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nil,
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false, true,
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},
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{
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"ipv6.google.com",
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[]string{
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"domain golang.org",
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"nameserver 8.8.8.8",
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"nameserver 2001:4860:4860::8888",
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},
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nil,
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false, true,
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},
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{
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"ipv6.google.com",
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[]string{
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"search x.golang.org y.golang.org",
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"nameserver 8.8.8.8",
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"nameserver 2001:4860:4860::8888",
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},
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nil,
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false, true,
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},
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// both A and AAAA records
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{
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"hostname.as112.net", // see RFC 7534
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[]string{
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"domain golang.org",
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"nameserver 2001:4860:4860::8888",
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"nameserver 8.8.8.8",
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},
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nil,
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true, true,
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},
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{
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"hostname.as112.net", // see RFC 7534
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[]string{
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"search x.golang.org y.golang.org",
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"nameserver 2001:4860:4860::8888",
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"nameserver 8.8.8.8",
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},
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nil,
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true, true,
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},
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}
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func TestGoLookupIPWithResolverConfig(t *testing.T) {
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fake := fakeDNSServer{func(n, s string, q *dnsMsg, _ time.Time) (*dnsMsg, error) {
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switch s {
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case "[2001:4860:4860::8888]:53", "8.8.8.8:53":
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break
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default:
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time.Sleep(10 * time.Millisecond)
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return nil, poll.ErrTimeout
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}
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r := &dnsMsg{
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dnsMsgHdr: dnsMsgHdr{
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id: q.id,
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response: true,
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},
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question: q.question,
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}
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for _, question := range q.question {
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switch question.Qtype {
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case dnsTypeA:
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switch question.Name {
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case "hostname.as112.net.":
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break
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case "ipv4.google.com.":
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r.answer = append(r.answer, &dnsRR_A{
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Hdr: dnsRR_Header{
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Name: q.question[0].Name,
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Rrtype: dnsTypeA,
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Class: dnsClassINET,
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Rdlength: 4,
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},
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A: TestAddr,
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})
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default:
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}
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case dnsTypeAAAA:
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switch question.Name {
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case "hostname.as112.net.":
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break
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case "ipv6.google.com.":
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r.answer = append(r.answer, &dnsRR_AAAA{
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Hdr: dnsRR_Header{
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Name: q.question[0].Name,
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Rrtype: dnsTypeAAAA,
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Class: dnsClassINET,
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Rdlength: 16,
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},
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AAAA: TestAddr6,
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})
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}
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}
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}
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return r, nil
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}}
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r := Resolver{PreferGo: true, Dial: fake.DialContext}
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|
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conf, err := newResolvConfTest()
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if err != nil {
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t.Fatal(err)
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}
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defer conf.teardown()
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|
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for _, tt := range goLookupIPWithResolverConfigTests {
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if err := conf.writeAndUpdate(tt.lines); err != nil {
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t.Error(err)
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continue
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}
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addrs, err := r.LookupIPAddr(context.Background(), tt.name)
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if err != nil {
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if err, ok := err.(*DNSError); !ok || tt.error != nil && (err.Name != tt.error.(*DNSError).Name || err.Server != tt.error.(*DNSError).Server || err.IsTimeout != tt.error.(*DNSError).IsTimeout) {
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t.Errorf("got %v; want %v", err, tt.error)
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}
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continue
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}
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if len(addrs) == 0 {
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t.Errorf("no records for %s", tt.name)
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}
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if !tt.a && !tt.aaaa && len(addrs) > 0 {
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t.Errorf("unexpected %v for %s", addrs, tt.name)
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}
|
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for _, addr := range addrs {
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if !tt.a && addr.IP.To4() != nil {
|
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t.Errorf("got %v; must not be IPv4 address", addr)
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}
|
|
if !tt.aaaa && addr.IP.To16() != nil && addr.IP.To4() == nil {
|
|
t.Errorf("got %v; must not be IPv6 address", addr)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Test that goLookupIPOrder falls back to the host file when no DNS servers are available.
|
|
func TestGoLookupIPOrderFallbackToFile(t *testing.T) {
|
|
fake := fakeDNSServer{func(n, s string, q *dnsMsg, tm time.Time) (*dnsMsg, error) {
|
|
r := &dnsMsg{
|
|
dnsMsgHdr: dnsMsgHdr{
|
|
id: q.id,
|
|
response: true,
|
|
},
|
|
question: q.question,
|
|
}
|
|
return r, nil
|
|
}}
|
|
r := Resolver{PreferGo: true, Dial: fake.DialContext}
|
|
|
|
// Add a config that simulates no dns servers being available.
|
|
conf, err := newResolvConfTest()
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := conf.writeAndUpdate([]string{}); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Redirect host file lookups.
|
|
defer func(orig string) { testHookHostsPath = orig }(testHookHostsPath)
|
|
testHookHostsPath = "testdata/hosts"
|
|
|
|
for _, order := range []hostLookupOrder{hostLookupFilesDNS, hostLookupDNSFiles} {
|
|
name := fmt.Sprintf("order %v", order)
|
|
|
|
// First ensure that we get an error when contacting a non-existent host.
|
|
_, _, err := r.goLookupIPCNAMEOrder(context.Background(), "notarealhost", order)
|
|
if err == nil {
|
|
t.Errorf("%s: expected error while looking up name not in hosts file", name)
|
|
continue
|
|
}
|
|
|
|
// Now check that we get an address when the name appears in the hosts file.
|
|
addrs, _, err := r.goLookupIPCNAMEOrder(context.Background(), "thor", order) // entry is in "testdata/hosts"
|
|
if err != nil {
|
|
t.Errorf("%s: expected to successfully lookup host entry", name)
|
|
continue
|
|
}
|
|
if len(addrs) != 1 {
|
|
t.Errorf("%s: expected exactly one result, but got %v", name, addrs)
|
|
continue
|
|
}
|
|
if got, want := addrs[0].String(), "127.1.1.1"; got != want {
|
|
t.Errorf("%s: address doesn't match expectation. got %v, want %v", name, got, want)
|
|
}
|
|
}
|
|
defer conf.teardown()
|
|
}
|
|
|
|
// Issue 12712.
|
|
// When using search domains, return the error encountered
|
|
// querying the original name instead of an error encountered
|
|
// querying a generated name.
|
|
func TestErrorForOriginalNameWhenSearching(t *testing.T) {
|
|
const fqdn = "doesnotexist.domain"
|
|
|
|
conf, err := newResolvConfTest()
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
defer conf.teardown()
|
|
|
|
if err := conf.writeAndUpdate([]string{"search servfail"}); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
|
|
fake := fakeDNSServer{func(_, _ string, q *dnsMsg, _ time.Time) (*dnsMsg, error) {
|
|
r := &dnsMsg{
|
|
dnsMsgHdr: dnsMsgHdr{
|
|
id: q.id,
|
|
response: true,
|
|
},
|
|
question: q.question,
|
|
}
|
|
|
|
switch q.question[0].Name {
|
|
case fqdn + ".servfail.":
|
|
r.rcode = dnsRcodeServerFailure
|
|
default:
|
|
r.rcode = dnsRcodeNameError
|
|
}
|
|
|
|
return r, nil
|
|
}}
|
|
|
|
cases := []struct {
|
|
strictErrors bool
|
|
wantErr *DNSError
|
|
}{
|
|
{true, &DNSError{Name: fqdn, Err: "server misbehaving", IsTemporary: true}},
|
|
{false, &DNSError{Name: fqdn, Err: errNoSuchHost.Error()}},
|
|
}
|
|
for _, tt := range cases {
|
|
r := Resolver{PreferGo: true, StrictErrors: tt.strictErrors, Dial: fake.DialContext}
|
|
_, err = r.LookupIPAddr(context.Background(), fqdn)
|
|
if err == nil {
|
|
t.Fatal("expected an error")
|
|
}
|
|
|
|
want := tt.wantErr
|
|
if err, ok := err.(*DNSError); !ok || err.Name != want.Name || err.Err != want.Err || err.IsTemporary != want.IsTemporary {
|
|
t.Errorf("got %v; want %v", err, want)
|
|
}
|
|
}
|
|
}
|
|
|
|
// Issue 15434. If a name server gives a lame referral, continue to the next.
|
|
func TestIgnoreLameReferrals(t *testing.T) {
|
|
conf, err := newResolvConfTest()
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
defer conf.teardown()
|
|
|
|
if err := conf.writeAndUpdate([]string{"nameserver 192.0.2.1", // the one that will give a lame referral
|
|
"nameserver 192.0.2.2"}); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
|
|
fake := fakeDNSServer{func(_, s string, q *dnsMsg, _ time.Time) (*dnsMsg, error) {
|
|
t.Log(s, q)
|
|
r := &dnsMsg{
|
|
dnsMsgHdr: dnsMsgHdr{
|
|
id: q.id,
|
|
response: true,
|
|
},
|
|
question: q.question,
|
|
}
|
|
|
|
if s == "192.0.2.2:53" {
|
|
r.recursion_available = true
|
|
if q.question[0].Qtype == dnsTypeA {
|
|
r.answer = []dnsRR{
|
|
&dnsRR_A{
|
|
Hdr: dnsRR_Header{
|
|
Name: q.question[0].Name,
|
|
Rrtype: dnsTypeA,
|
|
Class: dnsClassINET,
|
|
Rdlength: 4,
|
|
},
|
|
A: TestAddr,
|
|
},
|
|
}
|
|
}
|
|
}
|
|
|
|
return r, nil
|
|
}}
|
|
r := Resolver{PreferGo: true, Dial: fake.DialContext}
|
|
|
|
addrs, err := r.LookupIPAddr(context.Background(), "www.golang.org")
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
|
|
if got := len(addrs); got != 1 {
|
|
t.Fatalf("got %d addresses, want 1", got)
|
|
}
|
|
|
|
if got, want := addrs[0].String(), "192.0.2.1"; got != want {
|
|
t.Fatalf("got address %v, want %v", got, want)
|
|
}
|
|
}
|
|
|
|
func BenchmarkGoLookupIP(b *testing.B) {
|
|
testHookUninstaller.Do(uninstallTestHooks)
|
|
ctx := context.Background()
|
|
|
|
for i := 0; i < b.N; i++ {
|
|
goResolver.LookupIPAddr(ctx, "www.example.com")
|
|
}
|
|
}
|
|
|
|
func BenchmarkGoLookupIPNoSuchHost(b *testing.B) {
|
|
testHookUninstaller.Do(uninstallTestHooks)
|
|
ctx := context.Background()
|
|
|
|
for i := 0; i < b.N; i++ {
|
|
goResolver.LookupIPAddr(ctx, "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)
|
|
}
|
|
ctx := context.Background()
|
|
|
|
for i := 0; i < b.N; i++ {
|
|
goResolver.LookupIPAddr(ctx, "www.example.com")
|
|
}
|
|
}
|
|
|
|
type fakeDNSServer struct {
|
|
rh func(n, s string, q *dnsMsg, t time.Time) (*dnsMsg, error)
|
|
}
|
|
|
|
func (server *fakeDNSServer) DialContext(_ context.Context, n, s string) (Conn, error) {
|
|
return &fakeDNSConn{nil, server, n, s, nil, time.Time{}}, nil
|
|
}
|
|
|
|
type fakeDNSConn struct {
|
|
Conn
|
|
server *fakeDNSServer
|
|
n string
|
|
s string
|
|
q *dnsMsg
|
|
t time.Time
|
|
}
|
|
|
|
func (f *fakeDNSConn) Close() error {
|
|
return nil
|
|
}
|
|
|
|
func (f *fakeDNSConn) Read(b []byte) (int, error) {
|
|
resp, err := f.server.rh(f.n, f.s, f.q, f.t)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
bb, ok := resp.Pack()
|
|
if !ok {
|
|
return 0, errors.New("cannot marshal DNS message")
|
|
}
|
|
if len(b) < len(bb) {
|
|
return 0, errors.New("read would fragment DNS message")
|
|
}
|
|
|
|
copy(b, bb)
|
|
return len(bb), nil
|
|
}
|
|
|
|
func (f *fakeDNSConn) ReadFrom(b []byte) (int, Addr, error) {
|
|
return 0, nil, nil
|
|
}
|
|
|
|
func (f *fakeDNSConn) Write(b []byte) (int, error) {
|
|
f.q = new(dnsMsg)
|
|
if !f.q.Unpack(b) {
|
|
return 0, errors.New("cannot unmarshal DNS message")
|
|
}
|
|
return len(b), nil
|
|
}
|
|
|
|
func (f *fakeDNSConn) WriteTo(b []byte, addr Addr) (int, error) {
|
|
return 0, nil
|
|
}
|
|
|
|
func (f *fakeDNSConn) SetDeadline(t time.Time) error {
|
|
f.t = t
|
|
return nil
|
|
}
|
|
|
|
// UDP round-tripper algorithm should ignore invalid DNS responses (issue 13281).
|
|
func TestIgnoreDNSForgeries(t *testing.T) {
|
|
c, s := Pipe()
|
|
go func() {
|
|
b := make([]byte, 512)
|
|
n, err := s.Read(b)
|
|
if err != nil {
|
|
t.Error(err)
|
|
return
|
|
}
|
|
|
|
msg := &dnsMsg{}
|
|
if !msg.Unpack(b[:n]) {
|
|
t.Error("invalid DNS query")
|
|
return
|
|
}
|
|
|
|
s.Write([]byte("garbage DNS response packet"))
|
|
|
|
msg.response = true
|
|
msg.id++ // make invalid ID
|
|
b, ok := msg.Pack()
|
|
if !ok {
|
|
t.Error("failed to pack DNS response")
|
|
return
|
|
}
|
|
s.Write(b)
|
|
|
|
msg.id-- // restore original ID
|
|
msg.answer = []dnsRR{
|
|
&dnsRR_A{
|
|
Hdr: dnsRR_Header{
|
|
Name: "www.example.com.",
|
|
Rrtype: dnsTypeA,
|
|
Class: dnsClassINET,
|
|
Rdlength: 4,
|
|
},
|
|
A: TestAddr,
|
|
},
|
|
}
|
|
|
|
b, ok = msg.Pack()
|
|
if !ok {
|
|
t.Error("failed to pack DNS response")
|
|
return
|
|
}
|
|
s.Write(b)
|
|
}()
|
|
|
|
msg := &dnsMsg{
|
|
dnsMsgHdr: dnsMsgHdr{
|
|
id: 42,
|
|
},
|
|
question: []dnsQuestion{
|
|
{
|
|
Name: "www.example.com.",
|
|
Qtype: dnsTypeA,
|
|
Qclass: dnsClassINET,
|
|
},
|
|
},
|
|
}
|
|
|
|
dc := &dnsPacketConn{c}
|
|
resp, err := dc.dnsRoundTrip(msg)
|
|
if err != nil {
|
|
t.Fatalf("dnsRoundTripUDP failed: %v", err)
|
|
}
|
|
|
|
if got := resp.answer[0].(*dnsRR_A).A; got != TestAddr {
|
|
t.Errorf("got address %v, want %v", got, TestAddr)
|
|
}
|
|
}
|
|
|
|
// Issue 16865. If a name server times out, continue to the next.
|
|
func TestRetryTimeout(t *testing.T) {
|
|
conf, err := newResolvConfTest()
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
defer conf.teardown()
|
|
|
|
testConf := []string{
|
|
"nameserver 192.0.2.1", // the one that will timeout
|
|
"nameserver 192.0.2.2",
|
|
}
|
|
if err := conf.writeAndUpdate(testConf); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
|
|
var deadline0 time.Time
|
|
|
|
fake := fakeDNSServer{func(_, s string, q *dnsMsg, deadline time.Time) (*dnsMsg, error) {
|
|
t.Log(s, q, deadline)
|
|
|
|
if deadline.IsZero() {
|
|
t.Error("zero deadline")
|
|
}
|
|
|
|
if s == "192.0.2.1:53" {
|
|
deadline0 = deadline
|
|
time.Sleep(10 * time.Millisecond)
|
|
return nil, poll.ErrTimeout
|
|
}
|
|
|
|
if deadline.Equal(deadline0) {
|
|
t.Error("deadline didn't change")
|
|
}
|
|
|
|
return mockTXTResponse(q), nil
|
|
}}
|
|
r := &Resolver{PreferGo: true, Dial: fake.DialContext}
|
|
|
|
_, err = r.LookupTXT(context.Background(), "www.golang.org")
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
|
|
if deadline0.IsZero() {
|
|
t.Error("deadline0 still zero", deadline0)
|
|
}
|
|
}
|
|
|
|
func TestRotate(t *testing.T) {
|
|
// without rotation, always uses the first server
|
|
testRotate(t, false, []string{"192.0.2.1", "192.0.2.2"}, []string{"192.0.2.1:53", "192.0.2.1:53", "192.0.2.1:53"})
|
|
|
|
// with rotation, rotates through back to first
|
|
testRotate(t, true, []string{"192.0.2.1", "192.0.2.2"}, []string{"192.0.2.1:53", "192.0.2.2:53", "192.0.2.1:53"})
|
|
}
|
|
|
|
func testRotate(t *testing.T, rotate bool, nameservers, wantServers []string) {
|
|
conf, err := newResolvConfTest()
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
defer conf.teardown()
|
|
|
|
var confLines []string
|
|
for _, ns := range nameservers {
|
|
confLines = append(confLines, "nameserver "+ns)
|
|
}
|
|
if rotate {
|
|
confLines = append(confLines, "options rotate")
|
|
}
|
|
|
|
if err := conf.writeAndUpdate(confLines); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
|
|
var usedServers []string
|
|
fake := fakeDNSServer{func(_, s string, q *dnsMsg, deadline time.Time) (*dnsMsg, error) {
|
|
usedServers = append(usedServers, s)
|
|
return mockTXTResponse(q), nil
|
|
}}
|
|
r := Resolver{PreferGo: true, Dial: fake.DialContext}
|
|
|
|
// len(nameservers) + 1 to allow rotation to get back to start
|
|
for i := 0; i < len(nameservers)+1; i++ {
|
|
if _, err := r.LookupTXT(context.Background(), "www.golang.org"); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
}
|
|
|
|
if !reflect.DeepEqual(usedServers, wantServers) {
|
|
t.Errorf("rotate=%t got used servers:\n%v\nwant:\n%v", rotate, usedServers, wantServers)
|
|
}
|
|
}
|
|
|
|
func mockTXTResponse(q *dnsMsg) *dnsMsg {
|
|
r := &dnsMsg{
|
|
dnsMsgHdr: dnsMsgHdr{
|
|
id: q.id,
|
|
response: true,
|
|
recursion_available: true,
|
|
},
|
|
question: q.question,
|
|
answer: []dnsRR{
|
|
&dnsRR_TXT{
|
|
Hdr: dnsRR_Header{
|
|
Name: q.question[0].Name,
|
|
Rrtype: dnsTypeTXT,
|
|
Class: dnsClassINET,
|
|
},
|
|
Txt: "ok",
|
|
},
|
|
},
|
|
}
|
|
|
|
return r
|
|
}
|
|
|
|
// Issue 17448. With StrictErrors enabled, temporary errors should make
|
|
// LookupIP fail rather than return a partial result.
|
|
func TestStrictErrorsLookupIP(t *testing.T) {
|
|
conf, err := newResolvConfTest()
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
defer conf.teardown()
|
|
|
|
confData := []string{
|
|
"nameserver 192.0.2.53",
|
|
"search x.golang.org y.golang.org",
|
|
}
|
|
if err := conf.writeAndUpdate(confData); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
|
|
const name = "test-issue19592"
|
|
const server = "192.0.2.53:53"
|
|
const searchX = "test-issue19592.x.golang.org."
|
|
const searchY = "test-issue19592.y.golang.org."
|
|
const ip4 = "192.0.2.1"
|
|
const ip6 = "2001:db8::1"
|
|
|
|
type resolveWhichEnum int
|
|
const (
|
|
resolveOK resolveWhichEnum = iota
|
|
resolveOpError
|
|
resolveServfail
|
|
resolveTimeout
|
|
)
|
|
|
|
makeTempError := func(err string) error {
|
|
return &DNSError{
|
|
Err: err,
|
|
Name: name,
|
|
Server: server,
|
|
IsTemporary: true,
|
|
}
|
|
}
|
|
makeTimeout := func() error {
|
|
return &DNSError{
|
|
Err: poll.ErrTimeout.Error(),
|
|
Name: name,
|
|
Server: server,
|
|
IsTimeout: true,
|
|
}
|
|
}
|
|
makeNxDomain := func() error {
|
|
return &DNSError{
|
|
Err: errNoSuchHost.Error(),
|
|
Name: name,
|
|
Server: server,
|
|
}
|
|
}
|
|
|
|
cases := []struct {
|
|
desc string
|
|
resolveWhich func(quest *dnsQuestion) resolveWhichEnum
|
|
wantStrictErr error
|
|
wantLaxErr error
|
|
wantIPs []string
|
|
}{
|
|
{
|
|
desc: "No errors",
|
|
resolveWhich: func(quest *dnsQuestion) resolveWhichEnum {
|
|
return resolveOK
|
|
},
|
|
wantIPs: []string{ip4, ip6},
|
|
},
|
|
{
|
|
desc: "searchX error fails in strict mode",
|
|
resolveWhich: func(quest *dnsQuestion) resolveWhichEnum {
|
|
if quest.Name == searchX {
|
|
return resolveTimeout
|
|
}
|
|
return resolveOK
|
|
},
|
|
wantStrictErr: makeTimeout(),
|
|
wantIPs: []string{ip4, ip6},
|
|
},
|
|
{
|
|
desc: "searchX IPv4-only timeout fails in strict mode",
|
|
resolveWhich: func(quest *dnsQuestion) resolveWhichEnum {
|
|
if quest.Name == searchX && quest.Qtype == dnsTypeA {
|
|
return resolveTimeout
|
|
}
|
|
return resolveOK
|
|
},
|
|
wantStrictErr: makeTimeout(),
|
|
wantIPs: []string{ip4, ip6},
|
|
},
|
|
{
|
|
desc: "searchX IPv6-only servfail fails in strict mode",
|
|
resolveWhich: func(quest *dnsQuestion) resolveWhichEnum {
|
|
if quest.Name == searchX && quest.Qtype == dnsTypeAAAA {
|
|
return resolveServfail
|
|
}
|
|
return resolveOK
|
|
},
|
|
wantStrictErr: makeTempError("server misbehaving"),
|
|
wantIPs: []string{ip4, ip6},
|
|
},
|
|
{
|
|
desc: "searchY error always fails",
|
|
resolveWhich: func(quest *dnsQuestion) resolveWhichEnum {
|
|
if quest.Name == searchY {
|
|
return resolveTimeout
|
|
}
|
|
return resolveOK
|
|
},
|
|
wantStrictErr: makeTimeout(),
|
|
wantLaxErr: makeNxDomain(), // This one reaches the "test." FQDN.
|
|
},
|
|
{
|
|
desc: "searchY IPv4-only socket error fails in strict mode",
|
|
resolveWhich: func(quest *dnsQuestion) resolveWhichEnum {
|
|
if quest.Name == searchY && quest.Qtype == dnsTypeA {
|
|
return resolveOpError
|
|
}
|
|
return resolveOK
|
|
},
|
|
wantStrictErr: makeTempError("write: socket on fire"),
|
|
wantIPs: []string{ip6},
|
|
},
|
|
{
|
|
desc: "searchY IPv6-only timeout fails in strict mode",
|
|
resolveWhich: func(quest *dnsQuestion) resolveWhichEnum {
|
|
if quest.Name == searchY && quest.Qtype == dnsTypeAAAA {
|
|
return resolveTimeout
|
|
}
|
|
return resolveOK
|
|
},
|
|
wantStrictErr: makeTimeout(),
|
|
wantIPs: []string{ip4},
|
|
},
|
|
}
|
|
|
|
for i, tt := range cases {
|
|
fake := fakeDNSServer{func(_, s string, q *dnsMsg, deadline time.Time) (*dnsMsg, error) {
|
|
t.Log(s, q)
|
|
|
|
switch tt.resolveWhich(&q.question[0]) {
|
|
case resolveOK:
|
|
// Handle below.
|
|
case resolveOpError:
|
|
return nil, &OpError{Op: "write", Err: fmt.Errorf("socket on fire")}
|
|
case resolveServfail:
|
|
return &dnsMsg{
|
|
dnsMsgHdr: dnsMsgHdr{
|
|
id: q.id,
|
|
response: true,
|
|
rcode: dnsRcodeServerFailure,
|
|
},
|
|
question: q.question,
|
|
}, nil
|
|
case resolveTimeout:
|
|
return nil, poll.ErrTimeout
|
|
default:
|
|
t.Fatal("Impossible resolveWhich")
|
|
}
|
|
|
|
switch q.question[0].Name {
|
|
case searchX, name + ".":
|
|
// Return NXDOMAIN to utilize the search list.
|
|
return &dnsMsg{
|
|
dnsMsgHdr: dnsMsgHdr{
|
|
id: q.id,
|
|
response: true,
|
|
rcode: dnsRcodeNameError,
|
|
},
|
|
question: q.question,
|
|
}, nil
|
|
case searchY:
|
|
// Return records below.
|
|
default:
|
|
return nil, fmt.Errorf("Unexpected Name: %v", q.question[0].Name)
|
|
}
|
|
|
|
r := &dnsMsg{
|
|
dnsMsgHdr: dnsMsgHdr{
|
|
id: q.id,
|
|
response: true,
|
|
},
|
|
question: q.question,
|
|
}
|
|
switch q.question[0].Qtype {
|
|
case dnsTypeA:
|
|
r.answer = []dnsRR{
|
|
&dnsRR_A{
|
|
Hdr: dnsRR_Header{
|
|
Name: q.question[0].Name,
|
|
Rrtype: dnsTypeA,
|
|
Class: dnsClassINET,
|
|
Rdlength: 4,
|
|
},
|
|
A: TestAddr,
|
|
},
|
|
}
|
|
case dnsTypeAAAA:
|
|
r.answer = []dnsRR{
|
|
&dnsRR_AAAA{
|
|
Hdr: dnsRR_Header{
|
|
Name: q.question[0].Name,
|
|
Rrtype: dnsTypeAAAA,
|
|
Class: dnsClassINET,
|
|
Rdlength: 16,
|
|
},
|
|
AAAA: TestAddr6,
|
|
},
|
|
}
|
|
default:
|
|
return nil, fmt.Errorf("Unexpected Qtype: %v", q.question[0].Qtype)
|
|
}
|
|
return r, nil
|
|
}}
|
|
|
|
for _, strict := range []bool{true, false} {
|
|
r := Resolver{PreferGo: true, StrictErrors: strict, Dial: fake.DialContext}
|
|
ips, err := r.LookupIPAddr(context.Background(), name)
|
|
|
|
var wantErr error
|
|
if strict {
|
|
wantErr = tt.wantStrictErr
|
|
} else {
|
|
wantErr = tt.wantLaxErr
|
|
}
|
|
if !reflect.DeepEqual(err, wantErr) {
|
|
t.Errorf("#%d (%s) strict=%v: got err %#v; want %#v", i, tt.desc, strict, err, wantErr)
|
|
}
|
|
|
|
gotIPs := map[string]struct{}{}
|
|
for _, ip := range ips {
|
|
gotIPs[ip.String()] = struct{}{}
|
|
}
|
|
wantIPs := map[string]struct{}{}
|
|
if wantErr == nil {
|
|
for _, ip := range tt.wantIPs {
|
|
wantIPs[ip] = struct{}{}
|
|
}
|
|
}
|
|
if !reflect.DeepEqual(gotIPs, wantIPs) {
|
|
t.Errorf("#%d (%s) strict=%v: got ips %v; want %v", i, tt.desc, strict, gotIPs, wantIPs)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Issue 17448. With StrictErrors enabled, temporary errors should make
|
|
// LookupTXT stop walking the search list.
|
|
func TestStrictErrorsLookupTXT(t *testing.T) {
|
|
conf, err := newResolvConfTest()
|
|
if err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
defer conf.teardown()
|
|
|
|
confData := []string{
|
|
"nameserver 192.0.2.53",
|
|
"search x.golang.org y.golang.org",
|
|
}
|
|
if err := conf.writeAndUpdate(confData); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
|
|
const name = "test"
|
|
const server = "192.0.2.53:53"
|
|
const searchX = "test.x.golang.org."
|
|
const searchY = "test.y.golang.org."
|
|
const txt = "Hello World"
|
|
|
|
fake := fakeDNSServer{func(_, s string, q *dnsMsg, deadline time.Time) (*dnsMsg, error) {
|
|
t.Log(s, q)
|
|
|
|
switch q.question[0].Name {
|
|
case searchX:
|
|
return nil, poll.ErrTimeout
|
|
case searchY:
|
|
return mockTXTResponse(q), nil
|
|
default:
|
|
return nil, fmt.Errorf("Unexpected Name: %v", q.question[0].Name)
|
|
}
|
|
}}
|
|
|
|
for _, strict := range []bool{true, false} {
|
|
r := Resolver{StrictErrors: strict, Dial: fake.DialContext}
|
|
_, rrs, err := r.lookup(context.Background(), name, dnsTypeTXT)
|
|
var wantErr error
|
|
var wantRRs int
|
|
if strict {
|
|
wantErr = &DNSError{
|
|
Err: poll.ErrTimeout.Error(),
|
|
Name: name,
|
|
Server: server,
|
|
IsTimeout: true,
|
|
}
|
|
} else {
|
|
wantRRs = 1
|
|
}
|
|
if !reflect.DeepEqual(err, wantErr) {
|
|
t.Errorf("strict=%v: got err %#v; want %#v", strict, err, wantErr)
|
|
}
|
|
if len(rrs) != wantRRs {
|
|
t.Errorf("strict=%v: got %v; want %v", strict, len(rrs), wantRRs)
|
|
}
|
|
}
|
|
}
|