| // 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 ( |
| "context" |
| "errors" |
| "fmt" |
| "internal/poll" |
| "io/ioutil" |
| "os" |
| "path" |
| "reflect" |
| "strings" |
| "sync" |
| "testing" |
| "time" |
| |
| "golang_org/x/net/dns/dnsmessage" |
| ) |
| |
| var goResolver = Resolver{PreferGo: true} |
| |
| // Test address from 192.0.2.0/24 block, reserved by RFC 5737 for documentation. |
| var TestAddr = [4]byte{0xc0, 0x00, 0x02, 0x01} |
| |
| // Test address from 2001:db8::/32 block, reserved by RFC 3849 for documentation. |
| var TestAddr6 = [16]byte{0x20, 0x01, 0x0d, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1} |
| |
| func mustNewName(name string) dnsmessage.Name { |
| nn, err := dnsmessage.NewName(name) |
| if err != nil { |
| panic(fmt.Sprint("creating name: ", err)) |
| } |
| return nn |
| } |
| |
| func mustQuestion(name string, qtype dnsmessage.Type, class dnsmessage.Class) dnsmessage.Question { |
| return dnsmessage.Question{ |
| Name: mustNewName(name), |
| Type: qtype, |
| Class: class, |
| } |
| } |
| |
| var dnsTransportFallbackTests = []struct { |
| server string |
| question dnsmessage.Question |
| timeout int |
| rcode dnsmessage.RCode |
| }{ |
| // Querying "com." with qtype=255 usually makes an answer |
| // which requires more than 512 bytes. |
| {"8.8.8.8:53", mustQuestion("com.", dnsmessage.TypeALL, dnsmessage.ClassINET), 2, dnsmessage.RCodeSuccess}, |
| {"8.8.4.4:53", mustQuestion("com.", dnsmessage.TypeALL, dnsmessage.ClassINET), 4, dnsmessage.RCodeSuccess}, |
| } |
| |
| func TestDNSTransportFallback(t *testing.T) { |
| fake := fakeDNSServer{ |
| rh: func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) { |
| r := dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.Header.ID, |
| Response: true, |
| RCode: dnsmessage.RCodeSuccess, |
| }, |
| Questions: q.Questions, |
| } |
| if n == "udp" { |
| r.Header.Truncated = true |
| } |
| return r, nil |
| }, |
| } |
| r := Resolver{PreferGo: true, Dial: fake.DialContext} |
| for _, tt := range dnsTransportFallbackTests { |
| ctx, cancel := context.WithCancel(context.Background()) |
| defer cancel() |
| _, h, err := r.exchange(ctx, tt.server, tt.question, time.Second) |
| if err != nil { |
| t.Error(err) |
| continue |
| } |
| if h.RCode != tt.rcode { |
| t.Errorf("got %v from %v; want %v", h.RCode, tt.server, tt.rcode) |
| continue |
| } |
| } |
| } |
| |
| // See RFC 6761 for further information about the reserved, pseudo |
| // domain names. |
| var specialDomainNameTests = []struct { |
| question dnsmessage.Question |
| rcode dnsmessage.RCode |
| }{ |
| // Name resolution APIs and libraries should not recognize the |
| // followings as special. |
| {mustQuestion("1.0.168.192.in-addr.arpa.", dnsmessage.TypePTR, dnsmessage.ClassINET), dnsmessage.RCodeNameError}, |
| {mustQuestion("test.", dnsmessage.TypeALL, dnsmessage.ClassINET), dnsmessage.RCodeNameError}, |
| {mustQuestion("example.com.", dnsmessage.TypeALL, dnsmessage.ClassINET), dnsmessage.RCodeSuccess}, |
| |
| // 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 negative |
| // answers at DNS query-response interaction level. |
| {mustQuestion("localhost.", dnsmessage.TypeALL, dnsmessage.ClassINET), dnsmessage.RCodeNameError}, |
| {mustQuestion("invalid.", dnsmessage.TypeALL, dnsmessage.ClassINET), dnsmessage.RCodeNameError}, |
| } |
| |
| func TestSpecialDomainName(t *testing.T) { |
| fake := fakeDNSServer{rh: func(_, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) { |
| r := dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| }, |
| Questions: q.Questions, |
| } |
| |
| switch q.Questions[0].Name.String() { |
| case "example.com.": |
| r.Header.RCode = dnsmessage.RCodeSuccess |
| default: |
| r.Header.RCode = dnsmessage.RCodeNameError |
| } |
| |
| return r, nil |
| }} |
| r := Resolver{PreferGo: true, Dial: fake.DialContext} |
| server := "8.8.8.8:53" |
| for _, tt := range specialDomainNameTests { |
| ctx, cancel := context.WithCancel(context.Background()) |
| defer cancel() |
| _, h, err := r.exchange(ctx, server, tt.question, 3*time.Second) |
| if err != nil { |
| t.Error(err) |
| continue |
| } |
| if h.RCode != tt.rcode { |
| t.Errorf("got %v from %v; want %v", h.RCode, server, tt.rcode) |
| continue |
| } |
| } |
| } |
| |
| // Issue 13705: don't try to resolve onion addresses, etc |
| func TestAvoidDNSName(t *testing.T) { |
| tests := []struct { |
| name string |
| avoid bool |
| }{ |
| {"foo.com", false}, |
| {"foo.com.", false}, |
| |
| {"foo.onion.", true}, |
| {"foo.onion", true}, |
| {"foo.ONION", true}, |
| {"foo.ONION.", true}, |
| |
| // But do resolve *.local address; Issue 16739 |
| {"foo.local.", false}, |
| {"foo.local", false}, |
| {"foo.LOCAL", false}, |
| {"foo.LOCAL.", false}, |
| |
| {"", true}, // will be rejected earlier too |
| |
| // Without stuff before onion/local, they're fine to |
| // use DNS. With a search path, |
| // "onion.vegegtables.com" can use DNS. Without a |
| // search path (or with a trailing dot), the queries |
| // are just kinda useless, but don't reveal anything |
| // private. |
| {"local", false}, |
| {"onion", false}, |
| {"local.", false}, |
| {"onion.", false}, |
| } |
| for _, tt := range tests { |
| got := avoidDNS(tt.name) |
| if got != tt.avoid { |
| t.Errorf("avoidDNS(%q) = %v; want %v", tt.name, got, tt.avoid) |
| } |
| } |
| } |
| |
| var fakeDNSServerSuccessful = fakeDNSServer{rh: func(_, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) { |
| r := dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| }, |
| Questions: q.Questions, |
| } |
| if len(q.Questions) == 1 && q.Questions[0].Type == dnsmessage.TypeA { |
| r.Answers = []dnsmessage.Resource{ |
| { |
| Header: dnsmessage.ResourceHeader{ |
| Name: q.Questions[0].Name, |
| Type: dnsmessage.TypeA, |
| Class: dnsmessage.ClassINET, |
| Length: 4, |
| }, |
| Body: &dnsmessage.AResource{ |
| A: TestAddr, |
| }, |
| }, |
| } |
| } |
| return r, nil |
| }} |
| |
| // Issue 13705: don't try to resolve onion addresses, etc |
| func TestLookupTorOnion(t *testing.T) { |
| defer dnsWaitGroup.Wait() |
| r := Resolver{PreferGo: true, Dial: fakeDNSServerSuccessful.DialContext} |
| addrs, err := r.LookupIPAddr(context.Background(), "foo.onion") |
| if err != nil { |
| t.Fatalf("lookup = %v; want nil", err) |
| } |
| if len(addrs) > 0 { |
| t.Errorf("unexpected addresses: %v", addrs) |
| } |
| } |
| |
| 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, time.Now().Add(time.Hour)); err != nil { |
| return err |
| } |
| return nil |
| } |
| |
| func (conf *resolvConfTest) forceUpdate(name string, lastChecked time.Time) error { |
| dnsConf := dnsReadConfig(name) |
| conf.mu.Lock() |
| conf.dnsConfig = dnsConf |
| conf.mu.Unlock() |
| for i := 0; i < 5; i++ { |
| if conf.tryAcquireSema() { |
| conf.lastChecked = lastChecked |
| 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", time.Time{}) |
| 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{"8.8.8.8:53"}, |
| }, |
| { |
| 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{"8.8.4.4:53"}, |
| }, |
| } |
| |
| func TestUpdateResolvConf(t *testing.T) { |
| defer dnsWaitGroup.Wait() |
| |
| r := Resolver{PreferGo: true, Dial: fakeDNSServerSuccessful.DialContext} |
| |
| 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 := r.LookupIPAddr(context.Background(), 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) { |
| defer dnsWaitGroup.Wait() |
| fake := fakeDNSServer{rh: func(n, s string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) { |
| switch s { |
| case "[2001:4860:4860::8888]:53", "8.8.8.8:53": |
| break |
| default: |
| time.Sleep(10 * time.Millisecond) |
| return dnsmessage.Message{}, poll.ErrTimeout |
| } |
| r := dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| }, |
| Questions: q.Questions, |
| } |
| for _, question := range q.Questions { |
| switch question.Type { |
| case dnsmessage.TypeA: |
| switch question.Name.String() { |
| case "hostname.as112.net.": |
| break |
| case "ipv4.google.com.": |
| r.Answers = append(r.Answers, dnsmessage.Resource{ |
| Header: dnsmessage.ResourceHeader{ |
| Name: q.Questions[0].Name, |
| Type: dnsmessage.TypeA, |
| Class: dnsmessage.ClassINET, |
| Length: 4, |
| }, |
| Body: &dnsmessage.AResource{ |
| A: TestAddr, |
| }, |
| }) |
| default: |
| |
| } |
| case dnsmessage.TypeAAAA: |
| switch question.Name.String() { |
| case "hostname.as112.net.": |
| break |
| case "ipv6.google.com.": |
| r.Answers = append(r.Answers, dnsmessage.Resource{ |
| Header: dnsmessage.ResourceHeader{ |
| Name: q.Questions[0].Name, |
| Type: dnsmessage.TypeAAAA, |
| Class: dnsmessage.ClassINET, |
| Length: 16, |
| }, |
| Body: &dnsmessage.AAAAResource{ |
| AAAA: TestAddr6, |
| }, |
| }) |
| } |
| } |
| } |
| return r, nil |
| }} |
| r := Resolver{PreferGo: true, Dial: fake.DialContext} |
| |
| 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 |
| } |
| addrs, err := r.LookupIPAddr(context.Background(), tt.name) |
| if err != nil { |
| 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) { |
| 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) |
| } |
| } |
| } |
| } |
| |
| // Test that goLookupIPOrder falls back to the host file when no DNS servers are available. |
| func TestGoLookupIPOrderFallbackToFile(t *testing.T) { |
| defer dnsWaitGroup.Wait() |
| |
| fake := fakeDNSServer{rh: func(n, s string, q dnsmessage.Message, tm time.Time) (dnsmessage.Message, error) { |
| r := dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| }, |
| Questions: q.Questions, |
| } |
| 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) { |
| defer dnsWaitGroup.Wait() |
| |
| 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{rh: func(_, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) { |
| r := dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| }, |
| Questions: q.Questions, |
| } |
| |
| switch q.Questions[0].Name.String() { |
| case fqdn + ".servfail.": |
| r.Header.RCode = dnsmessage.RCodeServerFailure |
| default: |
| r.Header.RCode = dnsmessage.RCodeNameError |
| } |
| |
| 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) { |
| defer dnsWaitGroup.Wait() |
| |
| 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{rh: func(_, s string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) { |
| t.Log(s, q) |
| r := dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| }, |
| Questions: q.Questions, |
| } |
| |
| if s == "192.0.2.2:53" { |
| r.Header.RecursionAvailable = true |
| if q.Questions[0].Type == dnsmessage.TypeA { |
| r.Answers = []dnsmessage.Resource{ |
| { |
| Header: dnsmessage.ResourceHeader{ |
| Name: q.Questions[0].Name, |
| Type: dnsmessage.TypeA, |
| Class: dnsmessage.ClassINET, |
| Length: 4, |
| }, |
| Body: &dnsmessage.AResource{ |
| 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() |
| b.ReportAllocs() |
| |
| for i := 0; i < b.N; i++ { |
| goResolver.LookupIPAddr(ctx, "www.example.com") |
| } |
| } |
| |
| func BenchmarkGoLookupIPNoSuchHost(b *testing.B) { |
| testHookUninstaller.Do(uninstallTestHooks) |
| ctx := context.Background() |
| b.ReportAllocs() |
| |
| 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() |
| b.ReportAllocs() |
| |
| for i := 0; i < b.N; i++ { |
| goResolver.LookupIPAddr(ctx, "www.example.com") |
| } |
| } |
| |
| type fakeDNSServer struct { |
| rh func(n, s string, q dnsmessage.Message, t time.Time) (dnsmessage.Message, error) |
| alwaysTCP bool |
| } |
| |
| func (server *fakeDNSServer) DialContext(_ context.Context, n, s string) (Conn, error) { |
| if server.alwaysTCP || n == "tcp" || n == "tcp4" || n == "tcp6" { |
| return &fakeDNSConn{tcp: true, server: server, n: n, s: s}, nil |
| } |
| return &fakeDNSPacketConn{fakeDNSConn: fakeDNSConn{tcp: false, server: server, n: n, s: s}}, nil |
| } |
| |
| type fakeDNSConn struct { |
| Conn |
| tcp bool |
| server *fakeDNSServer |
| n string |
| s string |
| q dnsmessage.Message |
| t time.Time |
| buf []byte |
| } |
| |
| func (f *fakeDNSConn) Close() error { |
| return nil |
| } |
| |
| func (f *fakeDNSConn) Read(b []byte) (int, error) { |
| if len(f.buf) > 0 { |
| n := copy(b, f.buf) |
| f.buf = f.buf[n:] |
| return n, nil |
| } |
| |
| resp, err := f.server.rh(f.n, f.s, f.q, f.t) |
| if err != nil { |
| return 0, err |
| } |
| |
| bb := make([]byte, 2, 514) |
| bb, err = resp.AppendPack(bb) |
| if err != nil { |
| return 0, fmt.Errorf("cannot marshal DNS message: %v", err) |
| } |
| |
| if f.tcp { |
| l := len(bb) - 2 |
| bb[0] = byte(l >> 8) |
| bb[1] = byte(l) |
| f.buf = bb |
| return f.Read(b) |
| } |
| |
| bb = bb[2:] |
| if len(b) < len(bb) { |
| return 0, errors.New("read would fragment DNS message") |
| } |
| |
| copy(b, bb) |
| return len(bb), nil |
| } |
| |
| func (f *fakeDNSConn) Write(b []byte) (int, error) { |
| if f.tcp && len(b) >= 2 { |
| b = b[2:] |
| } |
| if f.q.Unpack(b) != nil { |
| return 0, fmt.Errorf("cannot unmarshal DNS message fake %s (%d)", f.n, len(b)) |
| } |
| return len(b), nil |
| } |
| |
| func (f *fakeDNSConn) SetDeadline(t time.Time) error { |
| f.t = t |
| return nil |
| } |
| |
| type fakeDNSPacketConn struct { |
| PacketConn |
| fakeDNSConn |
| } |
| |
| func (f *fakeDNSPacketConn) SetDeadline(t time.Time) error { |
| return f.fakeDNSConn.SetDeadline(t) |
| } |
| |
| func (f *fakeDNSPacketConn) Close() error { |
| return f.fakeDNSConn.Close() |
| } |
| |
| // 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 |
| } |
| |
| var msg dnsmessage.Message |
| if msg.Unpack(b[:n]) != nil { |
| t.Error("invalid DNS query:", err) |
| return |
| } |
| |
| s.Write([]byte("garbage DNS response packet")) |
| |
| msg.Header.Response = true |
| msg.Header.ID++ // make invalid ID |
| |
| if b, err = msg.Pack(); err != nil { |
| t.Error("failed to pack DNS response:", err) |
| return |
| } |
| s.Write(b) |
| |
| msg.Header.ID-- // restore original ID |
| msg.Answers = []dnsmessage.Resource{ |
| { |
| Header: dnsmessage.ResourceHeader{ |
| Name: mustNewName("www.example.com."), |
| Type: dnsmessage.TypeA, |
| Class: dnsmessage.ClassINET, |
| Length: 4, |
| }, |
| Body: &dnsmessage.AResource{ |
| A: TestAddr, |
| }, |
| }, |
| } |
| |
| b, err = msg.Pack() |
| if err != nil { |
| t.Error("failed to pack DNS response:", err) |
| return |
| } |
| s.Write(b) |
| }() |
| |
| msg := dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: 42, |
| }, |
| Questions: []dnsmessage.Question{ |
| { |
| Name: mustNewName("www.example.com."), |
| Type: dnsmessage.TypeA, |
| Class: dnsmessage.ClassINET, |
| }, |
| }, |
| } |
| |
| b, err := msg.Pack() |
| if err != nil { |
| t.Fatal("Pack failed:", err) |
| } |
| |
| p, _, err := dnsPacketRoundTrip(c, 42, msg.Questions[0], b) |
| if err != nil { |
| t.Fatalf("dnsPacketRoundTrip failed: %v", err) |
| } |
| |
| p.SkipAllQuestions() |
| as, err := p.AllAnswers() |
| if err != nil { |
| t.Fatal("AllAnswers failed:", err) |
| } |
| if got := as[0].Body.(*dnsmessage.AResource).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) { |
| defer dnsWaitGroup.Wait() |
| |
| 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{rh: func(_, s string, q dnsmessage.Message, deadline time.Time) (dnsmessage.Message, 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 dnsmessage.Message{}, 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) { |
| defer dnsWaitGroup.Wait() |
| |
| 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{rh: func(_, s string, q dnsmessage.Message, deadline time.Time) (dnsmessage.Message, 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 dnsmessage.Message) dnsmessage.Message { |
| r := dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| RecursionAvailable: true, |
| }, |
| Questions: q.Questions, |
| Answers: []dnsmessage.Resource{ |
| { |
| Header: dnsmessage.ResourceHeader{ |
| Name: q.Questions[0].Name, |
| Type: dnsmessage.TypeTXT, |
| Class: dnsmessage.ClassINET, |
| }, |
| Body: &dnsmessage.TXTResource{ |
| TXT: []string{"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) { |
| defer dnsWaitGroup.Wait() |
| |
| 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 dnsmessage.Question) resolveWhichEnum |
| wantStrictErr error |
| wantLaxErr error |
| wantIPs []string |
| }{ |
| { |
| desc: "No errors", |
| resolveWhich: func(quest dnsmessage.Question) resolveWhichEnum { |
| return resolveOK |
| }, |
| wantIPs: []string{ip4, ip6}, |
| }, |
| { |
| desc: "searchX error fails in strict mode", |
| resolveWhich: func(quest dnsmessage.Question) resolveWhichEnum { |
| if quest.Name.String() == searchX { |
| return resolveTimeout |
| } |
| return resolveOK |
| }, |
| wantStrictErr: makeTimeout(), |
| wantIPs: []string{ip4, ip6}, |
| }, |
| { |
| desc: "searchX IPv4-only timeout fails in strict mode", |
| resolveWhich: func(quest dnsmessage.Question) resolveWhichEnum { |
| if quest.Name.String() == searchX && quest.Type == dnsmessage.TypeA { |
| return resolveTimeout |
| } |
| return resolveOK |
| }, |
| wantStrictErr: makeTimeout(), |
| wantIPs: []string{ip4, ip6}, |
| }, |
| { |
| desc: "searchX IPv6-only servfail fails in strict mode", |
| resolveWhich: func(quest dnsmessage.Question) resolveWhichEnum { |
| if quest.Name.String() == searchX && quest.Type == dnsmessage.TypeAAAA { |
| return resolveServfail |
| } |
| return resolveOK |
| }, |
| wantStrictErr: makeTempError("server misbehaving"), |
| wantIPs: []string{ip4, ip6}, |
| }, |
| { |
| desc: "searchY error always fails", |
| resolveWhich: func(quest dnsmessage.Question) resolveWhichEnum { |
| if quest.Name.String() == 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 dnsmessage.Question) resolveWhichEnum { |
| if quest.Name.String() == searchY && quest.Type == dnsmessage.TypeA { |
| 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 dnsmessage.Question) resolveWhichEnum { |
| if quest.Name.String() == searchY && quest.Type == dnsmessage.TypeAAAA { |
| return resolveTimeout |
| } |
| return resolveOK |
| }, |
| wantStrictErr: makeTimeout(), |
| wantIPs: []string{ip4}, |
| }, |
| } |
| |
| for i, tt := range cases { |
| fake := fakeDNSServer{rh: func(_, s string, q dnsmessage.Message, deadline time.Time) (dnsmessage.Message, error) { |
| t.Log(s, q) |
| |
| switch tt.resolveWhich(q.Questions[0]) { |
| case resolveOK: |
| // Handle below. |
| case resolveOpError: |
| return dnsmessage.Message{}, &OpError{Op: "write", Err: fmt.Errorf("socket on fire")} |
| case resolveServfail: |
| return dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| RCode: dnsmessage.RCodeServerFailure, |
| }, |
| Questions: q.Questions, |
| }, nil |
| case resolveTimeout: |
| return dnsmessage.Message{}, poll.ErrTimeout |
| default: |
| t.Fatal("Impossible resolveWhich") |
| } |
| |
| switch q.Questions[0].Name.String() { |
| case searchX, name + ".": |
| // Return NXDOMAIN to utilize the search list. |
| return dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| RCode: dnsmessage.RCodeNameError, |
| }, |
| Questions: q.Questions, |
| }, nil |
| case searchY: |
| // Return records below. |
| default: |
| return dnsmessage.Message{}, fmt.Errorf("Unexpected Name: %v", q.Questions[0].Name) |
| } |
| |
| r := dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| }, |
| Questions: q.Questions, |
| } |
| switch q.Questions[0].Type { |
| case dnsmessage.TypeA: |
| r.Answers = []dnsmessage.Resource{ |
| { |
| Header: dnsmessage.ResourceHeader{ |
| Name: q.Questions[0].Name, |
| Type: dnsmessage.TypeA, |
| Class: dnsmessage.ClassINET, |
| Length: 4, |
| }, |
| Body: &dnsmessage.AResource{ |
| A: TestAddr, |
| }, |
| }, |
| } |
| case dnsmessage.TypeAAAA: |
| r.Answers = []dnsmessage.Resource{ |
| { |
| Header: dnsmessage.ResourceHeader{ |
| Name: q.Questions[0].Name, |
| Type: dnsmessage.TypeAAAA, |
| Class: dnsmessage.ClassINET, |
| Length: 16, |
| }, |
| Body: &dnsmessage.AAAAResource{ |
| AAAA: TestAddr6, |
| }, |
| }, |
| } |
| default: |
| return dnsmessage.Message{}, fmt.Errorf("Unexpected Type: %v", q.Questions[0].Type) |
| } |
| 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) { |
| defer dnsWaitGroup.Wait() |
| |
| 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{rh: func(_, s string, q dnsmessage.Message, deadline time.Time) (dnsmessage.Message, error) { |
| t.Log(s, q) |
| |
| switch q.Questions[0].Name.String() { |
| case searchX: |
| return dnsmessage.Message{}, poll.ErrTimeout |
| case searchY: |
| return mockTXTResponse(q), nil |
| default: |
| return dnsmessage.Message{}, fmt.Errorf("Unexpected Name: %v", q.Questions[0].Name) |
| } |
| }} |
| |
| for _, strict := range []bool{true, false} { |
| r := Resolver{StrictErrors: strict, Dial: fake.DialContext} |
| p, _, err := r.lookup(context.Background(), name, dnsmessage.TypeTXT) |
| 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) |
| } |
| a, err := p.AllAnswers() |
| if err != nil { |
| a = nil |
| } |
| if len(a) != wantRRs { |
| t.Errorf("strict=%v: got %v; want %v", strict, len(a), wantRRs) |
| } |
| } |
| } |
| |
| // Test for a race between uninstalling the test hooks and closing a |
| // socket connection. This used to fail when testing with -race. |
| func TestDNSGoroutineRace(t *testing.T) { |
| defer dnsWaitGroup.Wait() |
| |
| fake := fakeDNSServer{rh: func(n, s string, q dnsmessage.Message, t time.Time) (dnsmessage.Message, error) { |
| time.Sleep(10 * time.Microsecond) |
| return dnsmessage.Message{}, poll.ErrTimeout |
| }} |
| r := Resolver{PreferGo: true, Dial: fake.DialContext} |
| |
| // The timeout here is less than the timeout used by the server, |
| // so the goroutine started to query the (fake) server will hang |
| // around after this test is done if we don't call dnsWaitGroup.Wait. |
| ctx, cancel := context.WithTimeout(context.Background(), 2*time.Microsecond) |
| defer cancel() |
| _, err := r.LookupIPAddr(ctx, "where.are.they.now") |
| if err == nil { |
| t.Fatal("fake DNS lookup unexpectedly succeeded") |
| } |
| } |
| |
| func lookupWithFake(fake fakeDNSServer, name string, typ dnsmessage.Type) error { |
| r := Resolver{PreferGo: true, Dial: fake.DialContext} |
| |
| resolvConf.mu.RLock() |
| conf := resolvConf.dnsConfig |
| resolvConf.mu.RUnlock() |
| |
| ctx, cancel := context.WithCancel(context.Background()) |
| defer cancel() |
| |
| _, _, err := r.tryOneName(ctx, conf, name, typ) |
| return err |
| } |
| |
| // Issue 8434: verify that Temporary returns true on an error when rcode |
| // is SERVFAIL |
| func TestIssue8434(t *testing.T) { |
| err := lookupWithFake(fakeDNSServer{ |
| rh: func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) { |
| return dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| RCode: dnsmessage.RCodeServerFailure, |
| }, |
| Questions: q.Questions, |
| }, nil |
| }, |
| }, "golang.org.", dnsmessage.TypeALL) |
| if err == nil { |
| t.Fatal("expected an error") |
| } |
| if ne, ok := err.(Error); !ok { |
| t.Fatalf("err = %#v; wanted something supporting net.Error", err) |
| } else if !ne.Temporary() { |
| t.Fatalf("Temporary = false for err = %#v; want Temporary == true", err) |
| } |
| if de, ok := err.(*DNSError); !ok { |
| t.Fatalf("err = %#v; wanted a *net.DNSError", err) |
| } else if !de.IsTemporary { |
| t.Fatalf("IsTemporary = false for err = %#v; want IsTemporary == true", err) |
| } |
| } |
| |
| // TestNoSuchHost verifies that tryOneName works correctly when the domain does |
| // not exist. |
| // |
| // Issue 12778: verify that NXDOMAIN without RA bit errors as "no such host" |
| // and not "server misbehaving" |
| // |
| // Issue 25336: verify that NXDOMAIN errors fail fast. |
| // |
| // Issue 27525: verify that empty answers fail fast. |
| func TestNoSuchHost(t *testing.T) { |
| tests := []struct { |
| name string |
| f func(string, string, dnsmessage.Message, time.Time) (dnsmessage.Message, error) |
| }{ |
| { |
| "NXDOMAIN", |
| func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) { |
| return dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| RCode: dnsmessage.RCodeNameError, |
| RecursionAvailable: false, |
| }, |
| Questions: q.Questions, |
| }, nil |
| }, |
| }, |
| { |
| "no answers", |
| func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) { |
| return dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.ID, |
| Response: true, |
| RCode: dnsmessage.RCodeSuccess, |
| RecursionAvailable: false, |
| Authoritative: true, |
| }, |
| Questions: q.Questions, |
| }, nil |
| }, |
| }, |
| } |
| |
| for _, test := range tests { |
| t.Run(test.name, func(t *testing.T) { |
| lookups := 0 |
| err := lookupWithFake(fakeDNSServer{ |
| rh: func(n, s string, q dnsmessage.Message, d time.Time) (dnsmessage.Message, error) { |
| lookups++ |
| return test.f(n, s, q, d) |
| }, |
| }, ".", dnsmessage.TypeALL) |
| |
| if lookups != 1 { |
| t.Errorf("got %d lookups, wanted 1", lookups) |
| } |
| |
| if err == nil { |
| t.Fatal("expected an error") |
| } |
| de, ok := err.(*DNSError) |
| if !ok { |
| t.Fatalf("err = %#v; wanted a *net.DNSError", err) |
| } |
| if de.Err != errNoSuchHost.Error() { |
| t.Fatalf("Err = %#v; wanted %q", de.Err, errNoSuchHost.Error()) |
| } |
| }) |
| } |
| } |
| |
| // Issue 26573: verify that Conns that don't implement PacketConn are treated |
| // as streams even when udp was requested. |
| func TestDNSDialTCP(t *testing.T) { |
| fake := fakeDNSServer{ |
| rh: func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) { |
| r := dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.Header.ID, |
| Response: true, |
| RCode: dnsmessage.RCodeSuccess, |
| }, |
| Questions: q.Questions, |
| } |
| return r, nil |
| }, |
| alwaysTCP: true, |
| } |
| r := Resolver{PreferGo: true, Dial: fake.DialContext} |
| ctx := context.Background() |
| _, _, err := r.exchange(ctx, "0.0.0.0", mustQuestion("com.", dnsmessage.TypeALL, dnsmessage.ClassINET), time.Second) |
| if err != nil { |
| t.Fatal("exhange failed:", err) |
| } |
| } |
| |
| // Issue 27763: verify that two strings in one TXT record are concatenated. |
| func TestTXTRecordTwoStrings(t *testing.T) { |
| fake := fakeDNSServer{ |
| rh: func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) { |
| r := dnsmessage.Message{ |
| Header: dnsmessage.Header{ |
| ID: q.Header.ID, |
| Response: true, |
| RCode: dnsmessage.RCodeSuccess, |
| }, |
| Questions: q.Questions, |
| Answers: []dnsmessage.Resource{ |
| { |
| Header: dnsmessage.ResourceHeader{ |
| Name: q.Questions[0].Name, |
| Type: dnsmessage.TypeA, |
| Class: dnsmessage.ClassINET, |
| }, |
| Body: &dnsmessage.TXTResource{ |
| TXT: []string{"string1 ", "string2"}, |
| }, |
| }, |
| { |
| Header: dnsmessage.ResourceHeader{ |
| Name: q.Questions[0].Name, |
| Type: dnsmessage.TypeA, |
| Class: dnsmessage.ClassINET, |
| }, |
| Body: &dnsmessage.TXTResource{ |
| TXT: []string{"onestring"}, |
| }, |
| }, |
| }, |
| } |
| return r, nil |
| }, |
| } |
| r := Resolver{PreferGo: true, Dial: fake.DialContext} |
| txt, err := r.lookupTXT(context.Background(), "golang.org") |
| if err != nil { |
| t.Fatal("LookupTXT failed:", err) |
| } |
| if want := 2; len(txt) != want { |
| t.Fatalf("len(txt), got %d, want %d", len(txt), want) |
| } |
| if want := "string1 string2"; txt[0] != want { |
| t.Errorf("txt[0], got %q, want %q", txt[0], want) |
| } |
| if want := "onestring"; txt[1] != want { |
| t.Errorf("txt[1], got %q, want %q", txt[1], want) |
| } |
| } |
