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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package net
import (
"context"
"errors"
"fmt"
"internal/testenv"
"net/netip"
"reflect"
"runtime"
"slices"
"strings"
"sync"
"sync/atomic"
"testing"
"time"
)
var goResolver = Resolver{PreferGo: true}
func hasSuffixFold(s, suffix string) bool {
return strings.HasSuffix(strings.ToLower(s), strings.ToLower(suffix))
}
func lookupLocalhost(ctx context.Context, fn func(context.Context, string, string) ([]IPAddr, error), network, host string) ([]IPAddr, error) {
switch host {
case "localhost":
return []IPAddr{
{IP: IPv4(127, 0, 0, 1)},
{IP: IPv6loopback},
}, nil
default:
return fn(ctx, network, host)
}
}
// The Lookup APIs use various sources such as local database, DNS or
// mDNS, and may use platform-dependent DNS stub resolver if possible.
// The APIs accept any of forms for a query; host name in various
// encodings, UTF-8 encoded net name, domain name, FQDN or absolute
// FQDN, but the result would be one of the forms and it depends on
// the circumstances.
var lookupGoogleSRVTests = []struct {
service, proto, name string
cname, target string
}{
{
"ldap", "tcp", "google.com",
"google.com.", "google.com.",
},
{
"ldap", "tcp", "google.com.",
"google.com.", "google.com.",
},
// non-standard back door
{
"", "", "_ldap._tcp.google.com",
"google.com.", "google.com.",
},
{
"", "", "_ldap._tcp.google.com.",
"google.com.", "google.com.",
},
}
var backoffDuration = [...]time.Duration{time.Second, 5 * time.Second, 30 * time.Second}
func TestLookupGoogleSRV(t *testing.T) {
t.Parallel()
mustHaveExternalNetwork(t)
if runtime.GOOS == "ios" {
t.Skip("no resolv.conf on iOS")
}
if !supportsIPv4() || !*testIPv4 {
t.Skip("IPv4 is required")
}
attempts := 0
for i := 0; i < len(lookupGoogleSRVTests); i++ {
tt := lookupGoogleSRVTests[i]
cname, srvs, err := LookupSRV(tt.service, tt.proto, tt.name)
if err != nil {
testenv.SkipFlakyNet(t)
if attempts < len(backoffDuration) {
dur := backoffDuration[attempts]
t.Logf("backoff %v after failure %v\n", dur, err)
time.Sleep(dur)
attempts++
i--
continue
}
t.Fatal(err)
}
if len(srvs) == 0 {
t.Error("got no record")
}
if !hasSuffixFold(cname, tt.cname) {
t.Errorf("got %s; want %s", cname, tt.cname)
}
for _, srv := range srvs {
if !hasSuffixFold(srv.Target, tt.target) {
t.Errorf("got %v; want a record containing %s", srv, tt.target)
}
}
}
}
var lookupGmailMXTests = []struct {
name, host string
}{
{"gmail.com", "google.com."},
{"gmail.com.", "google.com."},
}
func TestLookupGmailMX(t *testing.T) {
t.Parallel()
mustHaveExternalNetwork(t)
if runtime.GOOS == "ios" {
t.Skip("no resolv.conf on iOS")
}
if !supportsIPv4() || !*testIPv4 {
t.Skip("IPv4 is required")
}
attempts := 0
for i := 0; i < len(lookupGmailMXTests); i++ {
tt := lookupGmailMXTests[i]
mxs, err := LookupMX(tt.name)
if err != nil {
testenv.SkipFlakyNet(t)
if attempts < len(backoffDuration) {
dur := backoffDuration[attempts]
t.Logf("backoff %v after failure %v\n", dur, err)
time.Sleep(dur)
attempts++
i--
continue
}
t.Fatal(err)
}
if len(mxs) == 0 {
t.Error("got no record")
}
for _, mx := range mxs {
if !hasSuffixFold(mx.Host, tt.host) {
t.Errorf("got %v; want a record containing %s", mx, tt.host)
}
}
}
}
var lookupGmailNSTests = []struct {
name, host string
}{
{"gmail.com", "google.com."},
{"gmail.com.", "google.com."},
}
func TestLookupGmailNS(t *testing.T) {
t.Parallel()
mustHaveExternalNetwork(t)
if runtime.GOOS == "ios" {
t.Skip("no resolv.conf on iOS")
}
if !supportsIPv4() || !*testIPv4 {
t.Skip("IPv4 is required")
}
attempts := 0
for i := 0; i < len(lookupGmailNSTests); i++ {
tt := lookupGmailNSTests[i]
nss, err := LookupNS(tt.name)
if err != nil {
testenv.SkipFlakyNet(t)
if attempts < len(backoffDuration) {
dur := backoffDuration[attempts]
t.Logf("backoff %v after failure %v\n", dur, err)
time.Sleep(dur)
attempts++
i--
continue
}
t.Fatal(err)
}
if len(nss) == 0 {
t.Error("got no record")
}
for _, ns := range nss {
if !hasSuffixFold(ns.Host, tt.host) {
t.Errorf("got %v; want a record containing %s", ns, tt.host)
}
}
}
}
var lookupGmailTXTTests = []struct {
name, txt, host string
}{
{"gmail.com", "spf", "google.com"},
{"gmail.com.", "spf", "google.com"},
}
func TestLookupGmailTXT(t *testing.T) {
if runtime.GOOS == "plan9" {
t.Skip("skipping on plan9; see https://golang.org/issue/29722")
}
t.Parallel()
mustHaveExternalNetwork(t)
if runtime.GOOS == "ios" {
t.Skip("no resolv.conf on iOS")
}
if !supportsIPv4() || !*testIPv4 {
t.Skip("IPv4 is required")
}
attempts := 0
for i := 0; i < len(lookupGmailTXTTests); i++ {
tt := lookupGmailTXTTests[i]
txts, err := LookupTXT(tt.name)
if err != nil {
testenv.SkipFlakyNet(t)
if attempts < len(backoffDuration) {
dur := backoffDuration[attempts]
t.Logf("backoff %v after failure %v\n", dur, err)
time.Sleep(dur)
attempts++
i--
continue
}
t.Fatal(err)
}
if len(txts) == 0 {
t.Error("got no record")
}
found := false
for _, txt := range txts {
if strings.Contains(txt, tt.txt) && (strings.HasSuffix(txt, tt.host) || strings.HasSuffix(txt, tt.host+".")) {
found = true
break
}
}
if !found {
t.Errorf("got %v; want a record containing %s, %s", txts, tt.txt, tt.host)
}
}
}
var lookupGooglePublicDNSAddrTests = []string{
"8.8.8.8",
"8.8.4.4",
"2001:4860:4860::8888",
"2001:4860:4860::8844",
}
func TestLookupGooglePublicDNSAddr(t *testing.T) {
mustHaveExternalNetwork(t)
if !supportsIPv4() || !supportsIPv6() || !*testIPv4 || !*testIPv6 {
t.Skip("both IPv4 and IPv6 are required")
}
defer dnsWaitGroup.Wait()
for _, ip := range lookupGooglePublicDNSAddrTests {
names, err := LookupAddr(ip)
if err != nil {
t.Fatal(err)
}
if len(names) == 0 {
t.Error("got no record")
}
for _, name := range names {
if !hasSuffixFold(name, ".google.com.") && !hasSuffixFold(name, ".google.") {
t.Errorf("got %q; want a record ending in .google.com. or .google.", name)
}
}
}
}
func TestLookupIPv6LinkLocalAddr(t *testing.T) {
if !supportsIPv6() || !*testIPv6 {
t.Skip("IPv6 is required")
}
defer dnsWaitGroup.Wait()
addrs, err := LookupHost("localhost")
if err != nil {
t.Fatal(err)
}
found := false
for _, addr := range addrs {
if addr == "fe80::1%lo0" {
found = true
break
}
}
if !found {
t.Skipf("not supported on %s", runtime.GOOS)
}
if _, err := LookupAddr("fe80::1%lo0"); err != nil {
t.Error(err)
}
}
func TestLookupIPv6LinkLocalAddrWithZone(t *testing.T) {
if !supportsIPv6() || !*testIPv6 {
t.Skip("IPv6 is required")
}
ipaddrs, err := DefaultResolver.LookupIPAddr(context.Background(), "fe80::1%lo0")
if err != nil {
t.Error(err)
}
for _, addr := range ipaddrs {
if e, a := "lo0", addr.Zone; e != a {
t.Errorf("wrong zone: want %q, got %q", e, a)
}
}
addrs, err := DefaultResolver.LookupHost(context.Background(), "fe80::1%lo0")
if err != nil {
t.Error(err)
}
for _, addr := range addrs {
if e, a := "fe80::1%lo0", addr; e != a {
t.Errorf("wrong host: want %q got %q", e, a)
}
}
}
var lookupCNAMETests = []struct {
name, cname string
}{
{"www.iana.org", "icann.org."},
{"www.iana.org.", "icann.org."},
{"www.google.com", "google.com."},
{"google.com", "google.com."},
{"cname-to-txt.go4.org", "test-txt-record.go4.org."},
}
func TestLookupCNAME(t *testing.T) {
mustHaveExternalNetwork(t)
testenv.SkipFlakyNet(t)
if !supportsIPv4() || !*testIPv4 {
t.Skip("IPv4 is required")
}
defer dnsWaitGroup.Wait()
attempts := 0
for i := 0; i < len(lookupCNAMETests); i++ {
tt := lookupCNAMETests[i]
cname, err := LookupCNAME(tt.name)
if err != nil {
testenv.SkipFlakyNet(t)
if attempts < len(backoffDuration) {
dur := backoffDuration[attempts]
t.Logf("backoff %v after failure %v\n", dur, err)
time.Sleep(dur)
attempts++
i--
continue
}
t.Fatal(err)
}
if !hasSuffixFold(cname, tt.cname) {
t.Errorf("got %s; want a record containing %s", cname, tt.cname)
}
}
}
var lookupGoogleHostTests = []struct {
name string
}{
{"google.com"},
{"google.com."},
}
func TestLookupGoogleHost(t *testing.T) {
mustHaveExternalNetwork(t)
testenv.SkipFlakyNet(t)
if !supportsIPv4() || !*testIPv4 {
t.Skip("IPv4 is required")
}
defer dnsWaitGroup.Wait()
for _, tt := range lookupGoogleHostTests {
addrs, err := LookupHost(tt.name)
if err != nil {
t.Fatal(err)
}
if len(addrs) == 0 {
t.Error("got no record")
}
for _, addr := range addrs {
if ParseIP(addr) == nil {
t.Errorf("got %q; want a literal IP address", addr)
}
}
}
}
func TestLookupLongTXT(t *testing.T) {
testenv.SkipFlaky(t, 22857)
mustHaveExternalNetwork(t)
defer dnsWaitGroup.Wait()
txts, err := LookupTXT("golang.rsc.io")
if err != nil {
t.Fatal(err)
}
slices.Sort(txts)
want := []string{
strings.Repeat("abcdefghijklmnopqrstuvwxyABCDEFGHJIKLMNOPQRSTUVWXY", 10),
"gophers rule",
}
if !slices.Equal(txts, want) {
t.Fatalf("LookupTXT golang.rsc.io incorrect\nhave %q\nwant %q", txts, want)
}
}
var lookupGoogleIPTests = []struct {
name string
}{
{"google.com"},
{"google.com."},
}
func TestLookupGoogleIP(t *testing.T) {
mustHaveExternalNetwork(t)
testenv.SkipFlakyNet(t)
if !supportsIPv4() || !*testIPv4 {
t.Skip("IPv4 is required")
}
defer dnsWaitGroup.Wait()
for _, tt := range lookupGoogleIPTests {
ips, err := LookupIP(tt.name)
if err != nil {
t.Fatal(err)
}
if len(ips) == 0 {
t.Error("got no record")
}
for _, ip := range ips {
if ip.To4() == nil && ip.To16() == nil {
t.Errorf("got %v; want an IP address", ip)
}
}
}
}
var revAddrTests = []struct {
Addr string
Reverse string
ErrPrefix string
}{
{"1.2.3.4", "4.3.2.1.in-addr.arpa.", ""},
{"245.110.36.114", "114.36.110.245.in-addr.arpa.", ""},
{"::ffff:12.34.56.78", "78.56.34.12.in-addr.arpa.", ""},
{"::1", "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa.", ""},
{"1::", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.0.ip6.arpa.", ""},
{"1234:567::89a:bcde", "e.d.c.b.a.9.8.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.6.5.0.4.3.2.1.ip6.arpa.", ""},
{"1234:567:fefe:bcbc:adad:9e4a:89a:bcde", "e.d.c.b.a.9.8.0.a.4.e.9.d.a.d.a.c.b.c.b.e.f.e.f.7.6.5.0.4.3.2.1.ip6.arpa.", ""},
{"1.2.3", "", "unrecognized address"},
{"1.2.3.4.5", "", "unrecognized address"},
{"1234:567:bcbca::89a:bcde", "", "unrecognized address"},
{"1234:567::bcbc:adad::89a:bcde", "", "unrecognized address"},
}
func TestReverseAddress(t *testing.T) {
defer dnsWaitGroup.Wait()
for i, tt := range revAddrTests {
a, err := reverseaddr(tt.Addr)
if len(tt.ErrPrefix) > 0 && err == nil {
t.Errorf("#%d: expected %q, got <nil> (error)", i, tt.ErrPrefix)
continue
}
if len(tt.ErrPrefix) == 0 && err != nil {
t.Errorf("#%d: expected <nil>, got %q (error)", i, err)
}
if err != nil && err.(*DNSError).Err != tt.ErrPrefix {
t.Errorf("#%d: expected %q, got %q (mismatched error)", i, tt.ErrPrefix, err.(*DNSError).Err)
}
if a != tt.Reverse {
t.Errorf("#%d: expected %q, got %q (reverse address)", i, tt.Reverse, a)
}
}
}
func TestDNSFlood(t *testing.T) {
if !*testDNSFlood {
t.Skip("test disabled; use -dnsflood to enable")
}
defer dnsWaitGroup.Wait()
var N = 5000
if runtime.GOOS == "darwin" || runtime.GOOS == "ios" {
// On Darwin this test consumes kernel threads much
// than other platforms for some reason.
// When we monitor the number of allocated Ms by
// observing on runtime.newm calls, we can see that it
// easily reaches the per process ceiling
// kern.num_threads when CGO_ENABLED=1 and
// GODEBUG=netdns=go.
N = 500
}
const timeout = 3 * time.Second
ctxHalfTimeout, cancel := context.WithTimeout(context.Background(), timeout/2)
defer cancel()
ctxTimeout, cancel := context.WithTimeout(context.Background(), timeout)
defer cancel()
c := make(chan error, 2*N)
for i := 0; i < N; i++ {
name := fmt.Sprintf("%d.net-test.golang.org", i)
go func() {
_, err := DefaultResolver.LookupIPAddr(ctxHalfTimeout, name)
c <- err
}()
go func() {
_, err := DefaultResolver.LookupIPAddr(ctxTimeout, name)
c <- err
}()
}
qstats := struct {
succeeded, failed int
timeout, temporary, other int
unknown int
}{}
deadline := time.After(timeout + time.Second)
for i := 0; i < 2*N; i++ {
select {
case <-deadline:
t.Fatal("deadline exceeded")
case err := <-c:
switch err := err.(type) {
case nil:
qstats.succeeded++
case Error:
qstats.failed++
if err.Timeout() {
qstats.timeout++
}
if err.Temporary() {
qstats.temporary++
}
if !err.Timeout() && !err.Temporary() {
qstats.other++
}
default:
qstats.failed++
qstats.unknown++
}
}
}
// A high volume of DNS queries for sub-domain of golang.org
// would be coordinated by authoritative or recursive server,
// or stub resolver which implements query-response rate
// limitation, so we can expect some query successes and more
// failures including timeout, temporary and other here.
// As a rule, unknown must not be shown but it might possibly
// happen due to issue 4856 for now.
t.Logf("%v succeeded, %v failed (%v timeout, %v temporary, %v other, %v unknown)", qstats.succeeded, qstats.failed, qstats.timeout, qstats.temporary, qstats.other, qstats.unknown)
}
func TestLookupDotsWithLocalSource(t *testing.T) {
if !supportsIPv4() || !*testIPv4 {
t.Skip("IPv4 is required")
}
mustHaveExternalNetwork(t)
defer dnsWaitGroup.Wait()
for i, fn := range []func() func(){forceGoDNS, forceCgoDNS} {
fixup := fn()
if fixup == nil {
continue
}
names, err := LookupAddr("127.0.0.1")
fixup()
if err != nil {
t.Logf("#%d: %v", i, err)
continue
}
mode := "netgo"
if i == 1 {
mode = "netcgo"
}
loop:
for i, name := range names {
if strings.Index(name, ".") == len(name)-1 { // "localhost" not "localhost."
for j := range names {
if j == i {
continue
}
if names[j] == name[:len(name)-1] {
// It's OK if we find the name without the dot,
// as some systems say 127.0.0.1 localhost localhost.
continue loop
}
}
t.Errorf("%s: got %s; want %s", mode, name, name[:len(name)-1])
} else if strings.Contains(name, ".") && !strings.HasSuffix(name, ".") { // "localhost.localdomain." not "localhost.localdomain"
t.Errorf("%s: got %s; want name ending with trailing dot", mode, name)
}
}
}
}
func TestLookupDotsWithRemoteSource(t *testing.T) {
if runtime.GOOS == "darwin" || runtime.GOOS == "ios" {
testenv.SkipFlaky(t, 27992)
}
mustHaveExternalNetwork(t)
testenv.SkipFlakyNet(t)
if !supportsIPv4() || !*testIPv4 {
t.Skip("IPv4 is required")
}
if runtime.GOOS == "ios" {
t.Skip("no resolv.conf on iOS")
}
defer dnsWaitGroup.Wait()
if fixup := forceGoDNS(); fixup != nil {
testDots(t, "go")
fixup()
}
if fixup := forceCgoDNS(); fixup != nil {
testDots(t, "cgo")
fixup()
}
}
func testDots(t *testing.T, mode string) {
names, err := LookupAddr("8.8.8.8") // Google dns server
if err != nil {
t.Errorf("LookupAddr(8.8.8.8): %v (mode=%v)", err, mode)
} else {
for _, name := range names {
if !hasSuffixFold(name, ".google.com.") && !hasSuffixFold(name, ".google.") {
t.Errorf("LookupAddr(8.8.8.8) = %v, want names ending in .google.com or .google with trailing dot (mode=%v)", names, mode)
break
}
}
}
cname, err := LookupCNAME("www.mit.edu")
if err != nil {
t.Errorf("LookupCNAME(www.mit.edu, mode=%v): %v", mode, err)
} else if !strings.HasSuffix(cname, ".") {
t.Errorf("LookupCNAME(www.mit.edu) = %v, want cname ending in . with trailing dot (mode=%v)", cname, mode)
}
mxs, err := LookupMX("google.com")
if err != nil {
t.Errorf("LookupMX(google.com): %v (mode=%v)", err, mode)
} else {
for _, mx := range mxs {
if !hasSuffixFold(mx.Host, ".google.com.") {
t.Errorf("LookupMX(google.com) = %v, want names ending in .google.com. with trailing dot (mode=%v)", mxString(mxs), mode)
break
}
}
}
nss, err := LookupNS("google.com")
if err != nil {
t.Errorf("LookupNS(google.com): %v (mode=%v)", err, mode)
} else {
for _, ns := range nss {
if !hasSuffixFold(ns.Host, ".google.com.") {
t.Errorf("LookupNS(google.com) = %v, want names ending in .google.com. with trailing dot (mode=%v)", nsString(nss), mode)
break
}
}
}
cname, srvs, err := LookupSRV("ldap", "tcp", "google.com")
if err != nil {
t.Errorf("LookupSRV(ldap, tcp, google.com): %v (mode=%v)", err, mode)
} else {
if !hasSuffixFold(cname, ".google.com.") {
t.Errorf("LookupSRV(ldap, tcp, google.com) returned cname=%v, want name ending in .google.com. with trailing dot (mode=%v)", cname, mode)
}
for _, srv := range srvs {
if !hasSuffixFold(srv.Target, ".google.com.") {
t.Errorf("LookupSRV(ldap, tcp, google.com) returned addrs=%v, want names ending in .google.com. with trailing dot (mode=%v)", srvString(srvs), mode)
break
}
}
}
}
func mxString(mxs []*MX) string {
var buf strings.Builder
sep := ""
fmt.Fprintf(&buf, "[")
for _, mx := range mxs {
fmt.Fprintf(&buf, "%s%s:%d", sep, mx.Host, mx.Pref)
sep = " "
}
fmt.Fprintf(&buf, "]")
return buf.String()
}
func nsString(nss []*NS) string {
var buf strings.Builder
sep := ""
fmt.Fprintf(&buf, "[")
for _, ns := range nss {
fmt.Fprintf(&buf, "%s%s", sep, ns.Host)
sep = " "
}
fmt.Fprintf(&buf, "]")
return buf.String()
}
func srvString(srvs []*SRV) string {
var buf strings.Builder
sep := ""
fmt.Fprintf(&buf, "[")
for _, srv := range srvs {
fmt.Fprintf(&buf, "%s%s:%d:%d:%d", sep, srv.Target, srv.Port, srv.Priority, srv.Weight)
sep = " "
}
fmt.Fprintf(&buf, "]")
return buf.String()
}
func TestLookupPort(t *testing.T) {
// See https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml
//
// Please be careful about adding new test cases.
// There are platforms which have incomplete mappings for
// restricted resource access and security reasons.
type test struct {
network string
name string
port int
ok bool
}
var tests = []test{
{"tcp", "0", 0, true},
{"udp", "0", 0, true},
{"udp", "domain", 53, true},
{"--badnet--", "zzz", 0, false},
{"tcp", "--badport--", 0, false},
{"tcp", "-1", 0, false},
{"tcp", "65536", 0, false},
{"udp", "-1", 0, false},
{"udp", "65536", 0, false},
{"tcp", "123456789", 0, false},
// Issue 13610: LookupPort("tcp", "")
{"tcp", "", 0, true},
{"tcp4", "", 0, true},
{"tcp6", "", 0, true},
{"udp", "", 0, true},
{"udp4", "", 0, true},
{"udp6", "", 0, true},
}
switch runtime.GOOS {
case "android":
if netGoBuildTag {
t.Skipf("not supported on %s without cgo; see golang.org/issues/14576", runtime.GOOS)
}
default:
tests = append(tests, test{"tcp", "http", 80, true})
}
for _, tt := range tests {
port, err := LookupPort(tt.network, tt.name)
if port != tt.port || (err == nil) != tt.ok {
t.Errorf("LookupPort(%q, %q) = %d, %v; want %d, error=%t", tt.network, tt.name, port, err, tt.port, !tt.ok)
}
if err != nil {
if perr := parseLookupPortError(err); perr != nil {
t.Error(perr)
}
}
}
}
// Like TestLookupPort but with minimal tests that should always pass
// because the answers are baked-in to the net package.
func TestLookupPort_Minimal(t *testing.T) {
type test struct {
network string
name string
port int
}
var tests = []test{
{"tcp", "http", 80},
{"tcp", "HTTP", 80}, // case shouldn't matter
{"tcp", "https", 443},
{"tcp", "ssh", 22},
{"tcp", "gopher", 70},
{"tcp4", "http", 80},
{"tcp6", "http", 80},
}
for _, tt := range tests {
port, err := LookupPort(tt.network, tt.name)
if port != tt.port || err != nil {
t.Errorf("LookupPort(%q, %q) = %d, %v; want %d, error=nil", tt.network, tt.name, port, err, tt.port)
}
}
}
func TestLookupProtocol_Minimal(t *testing.T) {
type test struct {
name string
want int
}
var tests = []test{
{"tcp", 6},
{"TcP", 6}, // case shouldn't matter
{"icmp", 1},
{"igmp", 2},
{"udp", 17},
{"ipv6-icmp", 58},
}
for _, tt := range tests {
got, err := lookupProtocol(context.Background(), tt.name)
if got != tt.want || err != nil {
t.Errorf("LookupProtocol(%q) = %d, %v; want %d, error=nil", tt.name, got, err, tt.want)
}
}
}
func TestLookupNonLDH(t *testing.T) {
defer dnsWaitGroup.Wait()
if fixup := forceGoDNS(); fixup != nil {
defer fixup()
}
// "LDH" stands for letters, digits, and hyphens and is the usual
// description of standard DNS names.
// This test is checking that other kinds of names are reported
// as not found, not reported as invalid names.
addrs, err := LookupHost("!!!.###.bogus..domain.")
if err == nil {
t.Fatalf("lookup succeeded: %v", addrs)
}
if !strings.HasSuffix(err.Error(), errNoSuchHost.Error()) {
t.Fatalf("lookup error = %v, want %v", err, errNoSuchHost)
}
if !err.(*DNSError).IsNotFound {
t.Fatalf("lookup error = %v, want true", err.(*DNSError).IsNotFound)
}
}
func TestLookupContextCancel(t *testing.T) {
mustHaveExternalNetwork(t)
testenv.SkipFlakyNet(t)
origTestHookLookupIP := testHookLookupIP
defer func() {
dnsWaitGroup.Wait()
testHookLookupIP = origTestHookLookupIP
}()
lookupCtx, cancelLookup := context.WithCancel(context.Background())
unblockLookup := make(chan struct{})
// Set testHookLookupIP to start a new, concurrent call to LookupIPAddr
// and cancel the original one, then block until the canceled call has returned
// (ensuring that it has performed any synchronous cleanup).
testHookLookupIP = func(
ctx context.Context,
fn func(context.Context, string, string) ([]IPAddr, error),
network string,
host string,
) ([]IPAddr, error) {
select {
case <-unblockLookup:
default:
// Start a concurrent LookupIPAddr for the same host while the caller is
// still blocked, and sleep a little to give it time to be deduplicated
// before we cancel (and unblock) the caller.
// (If the timing doesn't quite work out, we'll end up testing sequential
// calls instead of concurrent ones, but the test should still pass.)
t.Logf("starting concurrent LookupIPAddr")
dnsWaitGroup.Add(1)
go func() {
defer dnsWaitGroup.Done()
_, err := DefaultResolver.LookupIPAddr(context.Background(), host)
if err != nil {
t.Error(err)
}
}()
time.Sleep(1 * time.Millisecond)
}
cancelLookup()
<-unblockLookup
// If the concurrent lookup above is deduplicated to this one
// (as we expect to happen most of the time), it is important
// that the original call does not cancel the shared Context.
// (See https://go.dev/issue/22724.) Explicitly check for
// cancellation now, just in case fn itself doesn't notice it.
if err := ctx.Err(); err != nil {
t.Logf("testHookLookupIP canceled")
return nil, err
}
t.Logf("testHookLookupIP performing lookup")
return fn(ctx, network, host)
}
_, err := DefaultResolver.LookupIPAddr(lookupCtx, "google.com")
if dnsErr, ok := err.(*DNSError); !ok || dnsErr.Err != errCanceled.Error() {
t.Errorf("unexpected error from canceled, blocked LookupIPAddr: %v", err)
}
close(unblockLookup)
}
// Issue 24330: treat the nil *Resolver like a zero value. Verify nothing
// crashes if nil is used.
func TestNilResolverLookup(t *testing.T) {
mustHaveExternalNetwork(t)
var r *Resolver = nil
ctx := context.Background()
// Don't care about the results, just that nothing panics:
r.LookupAddr(ctx, "8.8.8.8")
r.LookupCNAME(ctx, "google.com")
r.LookupHost(ctx, "google.com")
r.LookupIPAddr(ctx, "google.com")
r.LookupIP(ctx, "ip", "google.com")
r.LookupMX(ctx, "gmail.com")
r.LookupNS(ctx, "google.com")
r.LookupPort(ctx, "tcp", "smtp")
r.LookupSRV(ctx, "service", "proto", "name")
r.LookupTXT(ctx, "gmail.com")
}
// TestLookupHostCancel verifies that lookup works even after many
// canceled lookups (see golang.org/issue/24178 for details).
func TestLookupHostCancel(t *testing.T) {
mustHaveExternalNetwork(t)
testenv.SkipFlakyNet(t)
t.Parallel() // Executes 600ms worth of sequential sleeps.
const (
google = "www.google.com"
invalidDomain = "invalid.invalid" // RFC 2606 reserves .invalid
n = 600 // this needs to be larger than threadLimit size
)
_, err := LookupHost(google)
if err != nil {
t.Fatal(err)
}
ctx, cancel := context.WithCancel(context.Background())
cancel()
for i := 0; i < n; i++ {
addr, err := DefaultResolver.LookupHost(ctx, invalidDomain)
if err == nil {
t.Fatalf("LookupHost(%q): returns %v, but should fail", invalidDomain, addr)
}
// Don't verify what the actual error is.
// We know that it must be non-nil because the domain is invalid,
// but we don't have any guarantee that LookupHost actually bothers
// to check for cancellation on the fast path.
// (For example, it could use a local cache to avoid blocking entirely.)
// The lookup may deduplicate in-flight requests, so give it time to settle
// in between.
time.Sleep(time.Millisecond * 1)
}
_, err = LookupHost(google)
if err != nil {
t.Fatal(err)
}
}
type lookupCustomResolver struct {
*Resolver
mu sync.RWMutex
dialed bool
}
func (lcr *lookupCustomResolver) dial() func(ctx context.Context, network, address string) (Conn, error) {
return func(ctx context.Context, network, address string) (Conn, error) {
lcr.mu.Lock()
lcr.dialed = true
lcr.mu.Unlock()
return Dial(network, address)
}
}
// TestConcurrentPreferGoResolversDial tests that multiple resolvers with the
// PreferGo option used concurrently are all dialed properly.
func TestConcurrentPreferGoResolversDial(t *testing.T) {
switch runtime.GOOS {
case "plan9":
// TODO: plan9 implementation of the resolver uses the Dial function since
// https://go.dev/cl/409234, this test could probably be reenabled.
t.Skipf("skip on %v", runtime.GOOS)
}
testenv.MustHaveExternalNetwork(t)
testenv.SkipFlakyNet(t)
defer dnsWaitGroup.Wait()
resolvers := make([]*lookupCustomResolver, 2)
for i := range resolvers {
cs := lookupCustomResolver{Resolver: &Resolver{PreferGo: true}}
cs.Dial = cs.dial()
resolvers[i] = &cs
}
var wg sync.WaitGroup
wg.Add(len(resolvers))
for i, resolver := range resolvers {
go func(r *Resolver, index int) {
defer wg.Done()
_, err := r.LookupIPAddr(context.Background(), "google.com")
if err != nil {
t.Errorf("lookup failed for resolver %d: %q", index, err)
}
}(resolver.Resolver, i)
}
wg.Wait()
if t.Failed() {
t.FailNow()
}
for i, resolver := range resolvers {
if !resolver.dialed {
t.Errorf("custom resolver %d not dialed during lookup", i)
}
}
}
var ipVersionTests = []struct {
network string
version byte
}{
{"tcp", 0},
{"tcp4", '4'},
{"tcp6", '6'},
{"udp", 0},
{"udp4", '4'},
{"udp6", '6'},
{"ip", 0},
{"ip4", '4'},
{"ip6", '6'},
{"ip7", 0},
{"", 0},
}
func TestIPVersion(t *testing.T) {
for _, tt := range ipVersionTests {
if version := ipVersion(tt.network); version != tt.version {
t.Errorf("Family for: %s. Expected: %s, Got: %s", tt.network,
string(tt.version), string(version))
}
}
}
// Issue 28600: The context that is used to lookup ips should always
// preserve the values from the context that was passed into LookupIPAddr.
func TestLookupIPAddrPreservesContextValues(t *testing.T) {
origTestHookLookupIP := testHookLookupIP
defer func() { testHookLookupIP = origTestHookLookupIP }()
keyValues := []struct {
key, value any
}{
{"key-1", 12},
{384, "value2"},
{new(float64), 137},
}
ctx := context.Background()
for _, kv := range keyValues {
ctx = context.WithValue(ctx, kv.key, kv.value)
}
wantIPs := []IPAddr{
{IP: IPv4(127, 0, 0, 1)},
{IP: IPv6loopback},
}
checkCtxValues := func(ctx_ context.Context, fn func(context.Context, string, string) ([]IPAddr, error), network, host string) ([]IPAddr, error) {
for _, kv := range keyValues {
g, w := ctx_.Value(kv.key), kv.value
if !reflect.DeepEqual(g, w) {
t.Errorf("Value lookup:\n\tGot: %v\n\tWant: %v", g, w)
}
}
return wantIPs, nil
}
testHookLookupIP = checkCtxValues
resolvers := []*Resolver{
nil,
new(Resolver),
}
for i, resolver := range resolvers {
gotIPs, err := resolver.LookupIPAddr(ctx, "golang.org")
if err != nil {
t.Errorf("Resolver #%d: unexpected error: %v", i, err)
}
if !reflect.DeepEqual(gotIPs, wantIPs) {
t.Errorf("#%d: mismatched IPAddr results\n\tGot: %v\n\tWant: %v", i, gotIPs, wantIPs)
}
}
}
// Issue 30521: The lookup group should call the resolver for each network.
func TestLookupIPAddrConcurrentCallsForNetworks(t *testing.T) {
origTestHookLookupIP := testHookLookupIP
defer func() { testHookLookupIP = origTestHookLookupIP }()
queries := [][]string{
{"udp", "golang.org"},
{"udp4", "golang.org"},
{"udp6", "golang.org"},
{"udp", "golang.org"},
{"udp", "golang.org"},
}
results := map[[2]string][]IPAddr{
{"udp", "golang.org"}: {
{IP: IPv4(127, 0, 0, 1)},
{IP: IPv6loopback},
},
{"udp4", "golang.org"}: {
{IP: IPv4(127, 0, 0, 1)},
},
{"udp6", "golang.org"}: {
{IP: IPv6loopback},
},
}
calls := int32(0)
waitCh := make(chan struct{})
testHookLookupIP = func(ctx context.Context, fn func(context.Context, string, string) ([]IPAddr, error), network, host string) ([]IPAddr, error) {
// We'll block until this is called one time for each different
// expected result. This will ensure that the lookup group would wait
// for the existing call if it was to be reused.
if atomic.AddInt32(&calls, 1) == int32(len(results)) {
close(waitCh)
}
select {
case <-waitCh:
case <-ctx.Done():
return nil, ctx.Err()
}
return results[[2]string{network, host}], nil
}
ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()
wg := sync.WaitGroup{}
for _, q := range queries {
network := q[0]
host := q[1]
wg.Add(1)
go func() {
defer wg.Done()
gotIPs, err := DefaultResolver.lookupIPAddr(ctx, network, host)
if err != nil {
t.Errorf("lookupIPAddr(%v, %v): unexpected error: %v", network, host, err)
}
wantIPs := results[[2]string{network, host}]
if !reflect.DeepEqual(gotIPs, wantIPs) {
t.Errorf("lookupIPAddr(%v, %v): mismatched IPAddr results\n\tGot: %v\n\tWant: %v", network, host, gotIPs, wantIPs)
}
}()
}
wg.Wait()
}
// Issue 53995: Resolver.LookupIP should return error for empty host name.
func TestResolverLookupIPWithEmptyHost(t *testing.T) {
_, err := DefaultResolver.LookupIP(context.Background(), "ip", "")
if err == nil {
t.Fatal("DefaultResolver.LookupIP for empty host success, want no host error")
}
if !strings.HasSuffix(err.Error(), errNoSuchHost.Error()) {
t.Fatalf("lookup error = %v, want %v", err, errNoSuchHost)
}
}
func TestWithUnexpiredValuesPreserved(t *testing.T) {
ctx, cancel := context.WithCancel(context.Background())
// Insert a value into it.
key, value := "key-1", 2
ctx = context.WithValue(ctx, key, value)
// Now use the "values preserving context" like
// we would for LookupIPAddr. See Issue 28600.
ctx = withUnexpiredValuesPreserved(ctx)
// Lookup before expiry.
if g, w := ctx.Value(key), value; g != w {
t.Errorf("Lookup before expiry: Got %v Want %v", g, w)
}
// Cancel the context.
cancel()
// Lookup after expiry should return nil
if g := ctx.Value(key); g != nil {
t.Errorf("Lookup after expiry: Got %v want nil", g)
}
}
// Issue 31597: don't panic on null byte in name
func TestLookupNullByte(t *testing.T) {
testenv.MustHaveExternalNetwork(t)
testenv.SkipFlakyNet(t)
LookupHost("foo\x00bar") // check that it doesn't panic; it used to on Windows
}
func TestResolverLookupIP(t *testing.T) {
testenv.MustHaveExternalNetwork(t)
v4Ok := supportsIPv4() && *testIPv4
v6Ok := supportsIPv6() && *testIPv6
defer dnsWaitGroup.Wait()
for _, impl := range []struct {
name string
fn func() func()
}{
{"go", forceGoDNS},
{"cgo", forceCgoDNS},
} {
t.Run("implementation: "+impl.name, func(t *testing.T) {
fixup := impl.fn()
if fixup == nil {
t.Skip("not supported")
}
defer fixup()
for _, network := range []string{"ip", "ip4", "ip6"} {
t.Run("network: "+network, func(t *testing.T) {
switch {
case network == "ip4" && !v4Ok:
t.Skip("IPv4 is not supported")
case network == "ip6" && !v6Ok:
t.Skip("IPv6 is not supported")
}
// google.com has both A and AAAA records.
const host = "google.com"
ips, err := DefaultResolver.LookupIP(context.Background(), network, host)
if err != nil {
testenv.SkipFlakyNet(t)
t.Fatalf("DefaultResolver.LookupIP(%q, %q): failed with unexpected error: %v", network, host, err)
}
var v4Addrs []netip.Addr
var v6Addrs []netip.Addr
for _, ip := range ips {
if addr, ok := netip.AddrFromSlice(ip); ok {
if addr.Is4() {
v4Addrs = append(v4Addrs, addr)
} else {
v6Addrs = append(v6Addrs, addr)
}
} else {
t.Fatalf("IP=%q is neither IPv4 nor IPv6", ip)
}
}
// Check that we got the expected addresses.
if network == "ip4" || network == "ip" && v4Ok {
if len(v4Addrs) == 0 {
t.Errorf("DefaultResolver.LookupIP(%q, %q): no IPv4 addresses", network, host)
}
}
if network == "ip6" || network == "ip" && v6Ok {
if len(v6Addrs) == 0 {
t.Errorf("DefaultResolver.LookupIP(%q, %q): no IPv6 addresses", network, host)
}
}
// Check that we didn't get any unexpected addresses.
if network == "ip6" && len(v4Addrs) > 0 {
t.Errorf("DefaultResolver.LookupIP(%q, %q): unexpected IPv4 addresses: %v", network, host, v4Addrs)
}
if network == "ip4" && len(v6Addrs) > 0 {
t.Errorf("DefaultResolver.LookupIP(%q, %q): unexpected IPv6 or IPv4-mapped IPv6 addresses: %v", network, host, v6Addrs)
}
})
}
})
}
}
// A context timeout should still return a DNSError.
func TestDNSTimeout(t *testing.T) {
origTestHookLookupIP := testHookLookupIP
defer func() { testHookLookupIP = origTestHookLookupIP }()
defer dnsWaitGroup.Wait()
timeoutHookGo := make(chan bool, 1)
timeoutHook := func(ctx context.Context, fn func(context.Context, string, string) ([]IPAddr, error), network, host string) ([]IPAddr, error) {
<-timeoutHookGo
return nil, context.DeadlineExceeded
}
testHookLookupIP = timeoutHook
checkErr := func(err error) {
t.Helper()
if err == nil {
t.Error("expected an error")
} else if dnserr, ok := err.(*DNSError); !ok {
t.Errorf("got error type %T, want %T", err, (*DNSError)(nil))
} else if !dnserr.IsTimeout {
t.Errorf("got error %#v, want IsTimeout == true", dnserr)
} else if isTimeout := dnserr.Timeout(); !isTimeout {
t.Errorf("got err.Timeout() == %t, want true", isTimeout)
}
}
// Single lookup.
timeoutHookGo <- true
_, err := LookupIP("golang.org")
checkErr(err)
// Double lookup.
var err1, err2 error
var wg sync.WaitGroup
wg.Add(2)
go func() {
defer wg.Done()
_, err1 = LookupIP("golang1.org")
}()
go func() {
defer wg.Done()
_, err2 = LookupIP("golang1.org")
}()
close(timeoutHookGo)
wg.Wait()
checkErr(err1)
checkErr(err2)
// Double lookup with context.
timeoutHookGo = make(chan bool)
ctx, cancel := context.WithTimeout(context.Background(), time.Nanosecond)
wg.Add(2)
go func() {
defer wg.Done()
_, err1 = DefaultResolver.LookupIPAddr(ctx, "golang2.org")
}()
go func() {
defer wg.Done()
_, err2 = DefaultResolver.LookupIPAddr(ctx, "golang2.org")
}()
time.Sleep(10 * time.Nanosecond)
close(timeoutHookGo)
wg.Wait()
checkErr(err1)
checkErr(err2)
cancel()
}
func TestLookupNoData(t *testing.T) {
if runtime.GOOS == "plan9" {
t.Skip("not supported on plan9")
}
mustHaveExternalNetwork(t)
testLookupNoData(t, "default resolver")
func() {
defer forceGoDNS()()
testLookupNoData(t, "forced go resolver")
}()
func() {
defer forceCgoDNS()()
testLookupNoData(t, "forced cgo resolver")
}()
}
func testLookupNoData(t *testing.T, prefix string) {
attempts := 0
for {
// Domain that doesn't have any A/AAAA RRs, but has different one (in this case a TXT),
// so that it returns an empty response without any error codes (NXDOMAIN).
_, err := LookupHost("golang.rsc.io.")
if err == nil {
t.Errorf("%v: unexpected success", prefix)
return
}
var dnsErr *DNSError
if errors.As(err, &dnsErr) {
succeeded := true
if !dnsErr.IsNotFound {
succeeded = false
t.Logf("%v: IsNotFound is set to false", prefix)
}
if dnsErr.Err != errNoSuchHost.Error() {
succeeded = false
t.Logf("%v: error message is not equal to: %v", prefix, errNoSuchHost.Error())
}
if succeeded {
return
}
}
testenv.SkipFlakyNet(t)
if attempts < len(backoffDuration) {
dur := backoffDuration[attempts]
t.Logf("%v: backoff %v after failure %v\n", prefix, dur, err)
time.Sleep(dur)
attempts++
continue
}
t.Errorf("%v: unexpected error: %v", prefix, err)
return
}
}
func TestLookupPortNotFound(t *testing.T) {
allResolvers(t, func(t *testing.T) {
_, err := LookupPort("udp", "_-unknown-service-")
var dnsErr *DNSError
if !errors.As(err, &dnsErr) || !dnsErr.IsNotFound {
t.Fatalf("unexpected error: %v", err)
}
})
}
// submissions service is only available through a tcp network, see:
// https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=submissions
var tcpOnlyService = func() string {
// plan9 does not have submissions service defined in the service database.
if runtime.GOOS == "plan9" {
return "https"
}
return "submissions"
}()
func TestLookupPortDifferentNetwork(t *testing.T) {
allResolvers(t, func(t *testing.T) {
_, err := LookupPort("udp", tcpOnlyService)
var dnsErr *DNSError
if !errors.As(err, &dnsErr) || !dnsErr.IsNotFound {
t.Fatalf("unexpected error: %v", err)
}
})
}
func TestLookupPortEmptyNetworkString(t *testing.T) {
allResolvers(t, func(t *testing.T) {
_, err := LookupPort("", tcpOnlyService)
if err != nil {
t.Fatalf("unexpected error: %v", err)
}
})
}
func TestLookupPortIPNetworkString(t *testing.T) {
allResolvers(t, func(t *testing.T) {
_, err := LookupPort("ip", tcpOnlyService)
if err != nil {
t.Fatalf("unexpected error: %v", err)
}
})
}
func TestLookupNoSuchHost(t *testing.T) {
mustHaveExternalNetwork(t)
const testNXDOMAIN = "invalid.invalid."
const testNODATA = "_ldap._tcp.google.com."
tests := []struct {
name string
query func() error
}{
{
name: "LookupCNAME NXDOMAIN",
query: func() error {
_, err := LookupCNAME(testNXDOMAIN)
return err
},
},
{
name: "LookupHost NXDOMAIN",
query: func() error {
_, err := LookupHost(testNXDOMAIN)
return err
},
},
{
name: "LookupHost NODATA",
query: func() error {
_, err := LookupHost(testNODATA)
return err
},
},
{
name: "LookupMX NXDOMAIN",
query: func() error {
_, err := LookupMX(testNXDOMAIN)
return err
},
},
{
name: "LookupMX NODATA",
query: func() error {
_, err := LookupMX(testNODATA)
return err
},
},
{
name: "LookupNS NXDOMAIN",
query: func() error {
_, err := LookupNS(testNXDOMAIN)
return err
},
},
{
name: "LookupNS NODATA",
query: func() error {
_, err := LookupNS(testNODATA)
return err
},
},
{
name: "LookupSRV NXDOMAIN",
query: func() error {
_, _, err := LookupSRV("unknown", "tcp", testNXDOMAIN)
return err
},
},
{
name: "LookupTXT NXDOMAIN",
query: func() error {
_, err := LookupTXT(testNXDOMAIN)
return err
},
},
{
name: "LookupTXT NODATA",
query: func() error {
_, err := LookupTXT(testNODATA)
return err
},
},
}
for _, v := range tests {
t.Run(v.name, func(t *testing.T) {
allResolvers(t, func(t *testing.T) {
attempts := 0
for {
err := v.query()
if err == nil {
t.Errorf("unexpected success")
return
}
if dnsErr, ok := err.(*DNSError); ok {
succeeded := true
if !dnsErr.IsNotFound {
succeeded = false
t.Log("IsNotFound is set to false")
}
if dnsErr.Err != errNoSuchHost.Error() {
succeeded = false
t.Logf("error message is not equal to: %v", errNoSuchHost.Error())
}
if succeeded {
return
}
}
testenv.SkipFlakyNet(t)
if attempts < len(backoffDuration) {
dur := backoffDuration[attempts]
t.Logf("backoff %v after failure %v\n", dur, err)
time.Sleep(dur)
attempts++
continue
}
t.Errorf("unexpected error: %v", err)
return
}
})
})
}
}
func TestDNSErrorUnwrap(t *testing.T) {
if runtime.GOOS == "plan9" {
// The Plan 9 implementation of the resolver doesn't use the Dial function yet. See https://go.dev/cl/409234
t.Skip("skipping on plan9")
}
rDeadlineExcceeded := &Resolver{PreferGo: true, Dial: func(ctx context.Context, network, address string) (Conn, error) {
return nil, context.DeadlineExceeded
}}
rCancelled := &Resolver{PreferGo: true, Dial: func(ctx context.Context, network, address string) (Conn, error) {
return nil, context.Canceled
}}
_, err := rDeadlineExcceeded.LookupHost(context.Background(), "test.go.dev")
if !errors.Is(err, context.DeadlineExceeded) {
t.Errorf("errors.Is(err, context.DeadlineExceeded) = false; want = true")
}
_, err = rCancelled.LookupHost(context.Background(), "test.go.dev")
if !errors.Is(err, context.Canceled) {
t.Errorf("errors.Is(err, context.Canceled) = false; want = true")
}
ctx, cancel := context.WithCancel(context.Background())
cancel()
_, err = goResolver.LookupHost(ctx, "text.go.dev")
if !errors.Is(err, context.Canceled) {
t.Errorf("errors.Is(err, context.Canceled) = false; want = true")
}
}