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tailscale/net/dns/recursive/recursive_test.go

742 lines
22 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package recursive
import (
"context"
"errors"
"flag"
"fmt"
"net"
"net/netip"
"reflect"
"strings"
"testing"
"time"
"github.com/miekg/dns"
"golang.org/x/exp/slices"
"tailscale.com/envknob"
"tailscale.com/tstest"
)
const testDomain = "tailscale.com"
// Recursively resolving the AWS console requires being able to handle CNAMEs,
// glue records, falling back from UDP to TCP for oversize queries, and more;
// it's a great integration test for DNS resolution and they can handle the
// traffic :)
const complicatedTestDomain = "console.aws.amazon.com"
var flagNetworkAccess = flag.Bool("enable-network-access", false, "run tests that need external network access")
func init() {
envknob.Setenv("TS_DEBUG_RECURSIVE_DNS", "true")
}
func newResolver(tb testing.TB) *Resolver {
clock := tstest.NewClock(tstest.ClockOpts{
Step: 50 * time.Millisecond,
})
return &Resolver{
Logf: tb.Logf,
timeNow: clock.Now,
}
}
func TestResolve(t *testing.T) {
if !*flagNetworkAccess {
t.SkipNow()
}
ctx := context.Background()
r := newResolver(t)
addrs, minTTL, err := r.Resolve(ctx, testDomain)
if err != nil {
t.Fatal(err)
}
t.Logf("addrs: %+v", addrs)
t.Logf("minTTL: %v", minTTL)
if len(addrs) < 1 {
t.Fatalf("expected at least one address")
}
if minTTL <= 10*time.Second || minTTL >= 24*time.Hour {
t.Errorf("invalid minimum TTL: %v", minTTL)
}
var has4, has6 bool
for _, addr := range addrs {
has4 = has4 || addr.Is4()
has6 = has6 || addr.Is6()
}
if !has4 {
t.Errorf("expected at least one IPv4 address")
}
if !has6 {
t.Errorf("expected at least one IPv6 address")
}
}
func TestResolveComplicated(t *testing.T) {
if !*flagNetworkAccess {
t.SkipNow()
}
ctx := context.Background()
r := newResolver(t)
addrs, minTTL, err := r.Resolve(ctx, complicatedTestDomain)
if err != nil {
t.Fatal(err)
}
t.Logf("addrs: %+v", addrs)
t.Logf("minTTL: %v", minTTL)
if len(addrs) < 1 {
t.Fatalf("expected at least one address")
}
if minTTL <= 10*time.Second || minTTL >= 24*time.Hour {
t.Errorf("invalid minimum TTL: %v", minTTL)
}
}
func TestResolveNoIPv6(t *testing.T) {
if !*flagNetworkAccess {
t.SkipNow()
}
r := newResolver(t)
r.NoIPv6 = true
addrs, _, err := r.Resolve(context.Background(), testDomain)
if err != nil {
t.Fatal(err)
}
t.Logf("addrs: %+v", addrs)
if len(addrs) < 1 {
t.Fatalf("expected at least one address")
}
for _, addr := range addrs {
if addr.Is6() {
t.Errorf("got unexpected IPv6 address: %v", addr)
}
}
}
func TestResolveFallbackToTCP(t *testing.T) {
var udpCalls, tcpCalls int
hook := func(nameserver netip.Addr, network string, req *dns.Msg) (*dns.Msg, error) {
if strings.HasPrefix(network, "udp") {
t.Logf("got %q query; returning truncated result", network)
udpCalls++
resp := &dns.Msg{}
resp.SetReply(req)
resp.Truncated = true
return resp, nil
}
t.Logf("got %q query; returning real result", network)
tcpCalls++
resp := &dns.Msg{}
resp.SetReply(req)
resp.Answer = append(resp.Answer, &dns.A{
Hdr: dns.RR_Header{
Name: req.Question[0].Name,
Rrtype: req.Question[0].Qtype,
Class: dns.ClassINET,
Ttl: 300,
},
A: net.IPv4(1, 2, 3, 4),
})
return resp, nil
}
r := newResolver(t)
r.testExchangeHook = hook
ctx := context.Background()
resp, err := r.queryNameserverProto(ctx, 0, "tailscale.com", netip.MustParseAddr("9.9.9.9"), "udp", dns.Type(dns.TypeA))
if err != nil {
t.Fatal(err)
}
if len(resp.Answer) < 1 {
t.Fatalf("no answers in response: %v", resp)
}
rrA, ok := resp.Answer[0].(*dns.A)
if !ok {
t.Fatalf("invalid RR type: %T", resp.Answer[0])
}
if !rrA.A.Equal(net.IPv4(1, 2, 3, 4)) {
t.Errorf("wanted A response 1.2.3.4, got: %v", rrA.A)
}
if tcpCalls != 1 {
t.Errorf("got %d, want 1 TCP calls", tcpCalls)
}
if udpCalls != 1 {
t.Errorf("got %d, want 1 UDP calls", udpCalls)
}
// Verify that we're cached and re-run to fetch from the cache.
if len(r.queryCache) < 1 {
t.Errorf("wanted entries in the query cache")
}
resp2, err := r.queryNameserverProto(ctx, 0, "tailscale.com", netip.MustParseAddr("9.9.9.9"), "udp", dns.Type(dns.TypeA))
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(resp, resp2) {
t.Errorf("expected equal responses; old=%+v new=%+v", resp, resp2)
}
// We didn't make any more network requests since we loaded from the cache.
if tcpCalls != 1 {
t.Errorf("got %d, want 1 TCP calls", tcpCalls)
}
if udpCalls != 1 {
t.Errorf("got %d, want 1 UDP calls", udpCalls)
}
}
func dnsIPRR(name string, addr netip.Addr) dns.RR {
if addr.Is4() {
return &dns.A{
Hdr: dns.RR_Header{
Name: name,
Rrtype: dns.TypeA,
Class: dns.ClassINET,
Ttl: 300,
},
A: net.IP(addr.AsSlice()),
}
}
return &dns.AAAA{
Hdr: dns.RR_Header{
Name: name,
Rrtype: dns.TypeAAAA,
Class: dns.ClassINET,
Ttl: 300,
},
AAAA: net.IP(addr.AsSlice()),
}
}
func cnameRR(name, target string) dns.RR {
return &dns.CNAME{
Hdr: dns.RR_Header{
Name: name,
Rrtype: dns.TypeCNAME,
Class: dns.ClassINET,
Ttl: 300,
},
Target: target,
}
}
func nsRR(name, target string) dns.RR {
return &dns.NS{
Hdr: dns.RR_Header{
Name: name,
Rrtype: dns.TypeNS,
Class: dns.ClassINET,
Ttl: 300,
},
Ns: target,
}
}
type mockReply struct {
name string
qtype dns.Type
resp *dns.Msg
}
type replyMock struct {
tb testing.TB
replies map[netip.Addr][]mockReply
}
func (r *replyMock) exchangeHook(nameserver netip.Addr, network string, req *dns.Msg) (*dns.Msg, error) {
if len(req.Question) != 1 {
r.tb.Fatalf("unsupported multiple or empty question: %v", req.Question)
}
question := req.Question[0]
replies := r.replies[nameserver]
if len(replies) == 0 {
r.tb.Fatalf("no configured replies for nameserver: %v", nameserver)
}
for _, reply := range replies {
if reply.name == question.Name && reply.qtype == dns.Type(question.Qtype) {
return reply.resp.Copy(), nil
}
}
r.tb.Fatalf("no replies found for query %q of type %v to %v", question.Name, question.Qtype, nameserver)
panic("unreachable")
}
// responses for mocking, shared between the following tests
var (
rootServerAddr = netip.MustParseAddr("198.41.0.4") // a.root-servers.net.
comNSAddr = netip.MustParseAddr("192.5.6.30") // a.gtld-servers.net.
// DNS response from the root nameservers for a .com nameserver
comRecord = &dns.Msg{
Ns: []dns.RR{nsRR("com.", "a.gtld-servers.net.")},
Extra: []dns.RR{dnsIPRR("a.gtld-servers.net.", comNSAddr)},
}
// Random Amazon nameservers that we use in glue records
amazonNS = netip.MustParseAddr("205.251.192.197")
amazonNSv6 = netip.MustParseAddr("2600:9000:5306:1600::1")
// Nameservers for the tailscale.com domain
tailscaleNameservers = &dns.Msg{
Ns: []dns.RR{
nsRR("tailscale.com.", "ns-197.awsdns-24.com."),
nsRR("tailscale.com.", "ns-557.awsdns-05.net."),
nsRR("tailscale.com.", "ns-1558.awsdns-02.co.uk."),
nsRR("tailscale.com.", "ns-1359.awsdns-41.org."),
},
Extra: []dns.RR{
dnsIPRR("ns-197.awsdns-24.com.", amazonNS),
},
}
)
func TestBasicRecursion(t *testing.T) {
mock := &replyMock{
tb: t,
replies: map[netip.Addr][]mockReply{
// Query to the root server returns the .com server + a glue record
rootServerAddr: {
{name: "tailscale.com.", qtype: dns.Type(dns.TypeA), resp: comRecord},
{name: "tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: comRecord},
},
// Query to the ".com" server return the nameservers for tailscale.com
comNSAddr: {
{name: "tailscale.com.", qtype: dns.Type(dns.TypeA), resp: tailscaleNameservers},
{name: "tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: tailscaleNameservers},
},
// Query to the actual nameserver works.
amazonNS: {
{name: "tailscale.com.", qtype: dns.Type(dns.TypeA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{
dnsIPRR("tailscale.com.", netip.MustParseAddr("13.248.141.131")),
dnsIPRR("tailscale.com.", netip.MustParseAddr("76.223.15.28")),
},
}},
{name: "tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{
dnsIPRR("tailscale.com.", netip.MustParseAddr("2600:9000:a602:b1e6:86d:8165:5e8c:295b")),
dnsIPRR("tailscale.com.", netip.MustParseAddr("2600:9000:a51d:27c1:1530:b9ef:2a6:b9e5")),
},
}},
},
},
}
r := newResolver(t)
r.testExchangeHook = mock.exchangeHook
r.rootServers = []netip.Addr{rootServerAddr}
// Query for tailscale.com, verify we get the right responses
ctx := context.Background()
addrs, minTTL, err := r.Resolve(ctx, "tailscale.com")
if err != nil {
t.Fatal(err)
}
wantAddrs := []netip.Addr{
netip.MustParseAddr("13.248.141.131"),
netip.MustParseAddr("76.223.15.28"),
netip.MustParseAddr("2600:9000:a602:b1e6:86d:8165:5e8c:295b"),
netip.MustParseAddr("2600:9000:a51d:27c1:1530:b9ef:2a6:b9e5"),
}
slices.SortFunc(addrs, func(x, y netip.Addr) bool { return x.String() < y.String() })
slices.SortFunc(wantAddrs, func(x, y netip.Addr) bool { return x.String() < y.String() })
if !reflect.DeepEqual(addrs, wantAddrs) {
t.Errorf("got addrs=%+v; want %+v", addrs, wantAddrs)
}
const wantMinTTL = 5 * time.Minute
if minTTL != wantMinTTL {
t.Errorf("got minTTL=%+v; want %+v", minTTL, wantMinTTL)
}
}
func TestNoAnswers(t *testing.T) {
mock := &replyMock{
tb: t,
replies: map[netip.Addr][]mockReply{
// Query to the root server returns the .com server + a glue record
rootServerAddr: {
{name: "tailscale.com.", qtype: dns.Type(dns.TypeA), resp: comRecord},
{name: "tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: comRecord},
},
// Query to the ".com" server return the nameservers for tailscale.com
comNSAddr: {
{name: "tailscale.com.", qtype: dns.Type(dns.TypeA), resp: tailscaleNameservers},
{name: "tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: tailscaleNameservers},
},
// Query to the actual nameserver returns no responses, authoritatively.
amazonNS: {
{name: "tailscale.com.", qtype: dns.Type(dns.TypeA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{},
}},
{name: "tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{},
}},
},
},
}
r := &Resolver{
Logf: t.Logf,
testExchangeHook: mock.exchangeHook,
rootServers: []netip.Addr{rootServerAddr},
}
// Query for tailscale.com, verify we get the right responses
_, _, err := r.Resolve(context.Background(), "tailscale.com")
if err == nil {
t.Fatalf("got no error, want error")
}
if !errors.Is(err, ErrAuthoritativeNoResponses) {
t.Fatalf("got err=%v, want %v", err, ErrAuthoritativeNoResponses)
}
}
func TestRecursionCNAME(t *testing.T) {
mock := &replyMock{
tb: t,
replies: map[netip.Addr][]mockReply{
// Query to the root server returns the .com server + a glue record
rootServerAddr: {
{name: "subdomain.otherdomain.com.", qtype: dns.Type(dns.TypeA), resp: comRecord},
{name: "subdomain.otherdomain.com.", qtype: dns.Type(dns.TypeAAAA), resp: comRecord},
{name: "subdomain.tailscale.com.", qtype: dns.Type(dns.TypeA), resp: comRecord},
{name: "subdomain.tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: comRecord},
},
// Query to the ".com" server return the nameservers for tailscale.com
comNSAddr: {
{name: "subdomain.otherdomain.com.", qtype: dns.Type(dns.TypeA), resp: tailscaleNameservers},
{name: "subdomain.otherdomain.com.", qtype: dns.Type(dns.TypeAAAA), resp: tailscaleNameservers},
{name: "subdomain.tailscale.com.", qtype: dns.Type(dns.TypeA), resp: tailscaleNameservers},
{name: "subdomain.tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: tailscaleNameservers},
},
// Query to the actual nameserver works.
amazonNS: {
{name: "subdomain.otherdomain.com.", qtype: dns.Type(dns.TypeA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{cnameRR("subdomain.otherdomain.com.", "subdomain.tailscale.com.")},
}},
{name: "subdomain.otherdomain.com.", qtype: dns.Type(dns.TypeAAAA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{cnameRR("subdomain.otherdomain.com.", "subdomain.tailscale.com.")},
}},
{name: "subdomain.tailscale.com.", qtype: dns.Type(dns.TypeA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{dnsIPRR("tailscale.com.", netip.MustParseAddr("13.248.141.131"))},
}},
{name: "subdomain.tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{dnsIPRR("tailscale.com.", netip.MustParseAddr("2600:9000:a602:b1e6:86d:8165:5e8c:295b"))},
}},
},
},
}
r := &Resolver{
Logf: t.Logf,
testExchangeHook: mock.exchangeHook,
rootServers: []netip.Addr{rootServerAddr},
}
// Query for tailscale.com, verify we get the right responses
addrs, minTTL, err := r.Resolve(context.Background(), "subdomain.otherdomain.com")
if err != nil {
t.Fatal(err)
}
wantAddrs := []netip.Addr{
netip.MustParseAddr("13.248.141.131"),
netip.MustParseAddr("2600:9000:a602:b1e6:86d:8165:5e8c:295b"),
}
slices.SortFunc(addrs, func(x, y netip.Addr) bool { return x.String() < y.String() })
slices.SortFunc(wantAddrs, func(x, y netip.Addr) bool { return x.String() < y.String() })
if !reflect.DeepEqual(addrs, wantAddrs) {
t.Errorf("got addrs=%+v; want %+v", addrs, wantAddrs)
}
const wantMinTTL = 5 * time.Minute
if minTTL != wantMinTTL {
t.Errorf("got minTTL=%+v; want %+v", minTTL, wantMinTTL)
}
}
func TestRecursionNoGlue(t *testing.T) {
coukNS := netip.MustParseAddr("213.248.216.1")
coukRecord := &dns.Msg{
Ns: []dns.RR{nsRR("com.", "dns1.nic.uk.")},
Extra: []dns.RR{dnsIPRR("dns1.nic.uk.", coukNS)},
}
intermediateNS := netip.MustParseAddr("205.251.193.66") // g-ns-322.awsdns-02.co.uk.
intermediateRecord := &dns.Msg{
Ns: []dns.RR{nsRR("awsdns-02.co.uk.", "g-ns-322.awsdns-02.co.uk.")},
Extra: []dns.RR{dnsIPRR("g-ns-322.awsdns-02.co.uk.", intermediateNS)},
}
const amazonNameserver = "ns-1558.awsdns-02.co.uk."
tailscaleNameservers := &dns.Msg{
Ns: []dns.RR{
nsRR("tailscale.com.", amazonNameserver),
},
}
tailscaleResponses := []mockReply{
{name: "tailscale.com.", qtype: dns.Type(dns.TypeA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{dnsIPRR("tailscale.com.", netip.MustParseAddr("13.248.141.131"))},
}},
{name: "tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{dnsIPRR("tailscale.com.", netip.MustParseAddr("2600:9000:a602:b1e6:86d:8165:5e8c:295b"))},
}},
}
mock := &replyMock{
tb: t,
replies: map[netip.Addr][]mockReply{
rootServerAddr: {
// Query to the root server returns the .com server + a glue record
{name: "tailscale.com.", qtype: dns.Type(dns.TypeA), resp: comRecord},
{name: "tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: comRecord},
// Querying the .co.uk nameserver returns the .co.uk nameserver + a glue record.
{name: amazonNameserver, qtype: dns.Type(dns.TypeA), resp: coukRecord},
{name: amazonNameserver, qtype: dns.Type(dns.TypeAAAA), resp: coukRecord},
},
// Queries to the ".com" server return the nameservers
// for tailscale.com, which don't contain a glue
// record.
comNSAddr: {
{name: "tailscale.com.", qtype: dns.Type(dns.TypeA), resp: tailscaleNameservers},
{name: "tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: tailscaleNameservers},
},
// Queries to the ".co.uk" nameserver returns the
// address of the intermediate Amazon nameserver.
coukNS: {
{name: amazonNameserver, qtype: dns.Type(dns.TypeA), resp: intermediateRecord},
{name: amazonNameserver, qtype: dns.Type(dns.TypeAAAA), resp: intermediateRecord},
},
// Queries to the intermediate nameserver returns an
// answer for the final Amazon nameserver.
intermediateNS: {
{name: amazonNameserver, qtype: dns.Type(dns.TypeA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{dnsIPRR(amazonNameserver, amazonNS)},
}},
{name: amazonNameserver, qtype: dns.Type(dns.TypeAAAA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{dnsIPRR(amazonNameserver, amazonNSv6)},
}},
},
// Queries to the actual nameserver work and return
// responses to the query.
amazonNS: tailscaleResponses,
amazonNSv6: tailscaleResponses,
},
}
r := newResolver(t)
r.testExchangeHook = mock.exchangeHook
r.rootServers = []netip.Addr{rootServerAddr}
// Query for tailscale.com, verify we get the right responses
addrs, minTTL, err := r.Resolve(context.Background(), "tailscale.com")
if err != nil {
t.Fatal(err)
}
wantAddrs := []netip.Addr{
netip.MustParseAddr("13.248.141.131"),
netip.MustParseAddr("2600:9000:a602:b1e6:86d:8165:5e8c:295b"),
}
slices.SortFunc(addrs, func(x, y netip.Addr) bool { return x.String() < y.String() })
slices.SortFunc(wantAddrs, func(x, y netip.Addr) bool { return x.String() < y.String() })
if !reflect.DeepEqual(addrs, wantAddrs) {
t.Errorf("got addrs=%+v; want %+v", addrs, wantAddrs)
}
const wantMinTTL = 5 * time.Minute
if minTTL != wantMinTTL {
t.Errorf("got minTTL=%+v; want %+v", minTTL, wantMinTTL)
}
}
func TestRecursionLimit(t *testing.T) {
mock := &replyMock{
tb: t,
replies: map[netip.Addr][]mockReply{},
}
// Fill out a CNAME chain equal to our recursion limit; we won't get
// this far since each CNAME is more than 1 level "deep", but this
// ensures that we have more than the limit.
for i := 0; i < maxDepth+1; i++ {
curr := fmt.Sprintf("%d-tailscale.com.", i)
tailscaleNameservers := &dns.Msg{
Ns: []dns.RR{nsRR(curr, "ns-197.awsdns-24.com.")},
Extra: []dns.RR{dnsIPRR("ns-197.awsdns-24.com.", amazonNS)},
}
// Query to the root server returns the .com server + a glue record
mock.replies[rootServerAddr] = append(mock.replies[rootServerAddr],
mockReply{name: curr, qtype: dns.Type(dns.TypeA), resp: comRecord},
mockReply{name: curr, qtype: dns.Type(dns.TypeAAAA), resp: comRecord},
)
// Query to the ".com" server return the nameservers for NN-tailscale.com
mock.replies[comNSAddr] = append(mock.replies[comNSAddr],
mockReply{name: curr, qtype: dns.Type(dns.TypeA), resp: tailscaleNameservers},
mockReply{name: curr, qtype: dns.Type(dns.TypeAAAA), resp: tailscaleNameservers},
)
// Queries to the nameserver return a CNAME for the n+1th server.
next := fmt.Sprintf("%d-tailscale.com.", i+1)
mock.replies[amazonNS] = append(mock.replies[amazonNS],
mockReply{
name: curr,
qtype: dns.Type(dns.TypeA),
resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{cnameRR(curr, next)},
},
},
mockReply{
name: curr,
qtype: dns.Type(dns.TypeAAAA),
resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{cnameRR(curr, next)},
},
},
)
}
r := newResolver(t)
r.testExchangeHook = mock.exchangeHook
r.rootServers = []netip.Addr{rootServerAddr}
// Query for the first node in the chain, 0-tailscale.com, and verify
// we get a max-depth error.
ctx := context.Background()
_, _, err := r.Resolve(ctx, "0-tailscale.com")
if err == nil {
t.Fatal("expected error, got nil")
} else if !errors.Is(err, ErrMaxDepth) {
t.Fatalf("got err=%v, want ErrMaxDepth", err)
}
}
func TestInvalidResponses(t *testing.T) {
mock := &replyMock{
tb: t,
replies: map[netip.Addr][]mockReply{
// Query to the root server returns the .com server + a glue record
rootServerAddr: {
{name: "tailscale.com.", qtype: dns.Type(dns.TypeA), resp: comRecord},
{name: "tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: comRecord},
},
// Query to the ".com" server return the nameservers for tailscale.com
comNSAddr: {
{name: "tailscale.com.", qtype: dns.Type(dns.TypeA), resp: tailscaleNameservers},
{name: "tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: tailscaleNameservers},
},
// Query to the actual nameserver returns an invalid IP address
amazonNS: {
{name: "tailscale.com.", qtype: dns.Type(dns.TypeA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
Answer: []dns.RR{&dns.A{
Hdr: dns.RR_Header{
Name: "tailscale.com.",
Rrtype: dns.TypeA,
Class: dns.ClassINET,
Ttl: 300,
},
// Note: this is an IPv6 addr in an IPv4 response
A: net.IP(netip.MustParseAddr("2600:9000:a51d:27c1:1530:b9ef:2a6:b9e5").AsSlice()),
}},
}},
{name: "tailscale.com.", qtype: dns.Type(dns.TypeAAAA), resp: &dns.Msg{
MsgHdr: dns.MsgHdr{Authoritative: true},
// This an IPv4 response to an IPv6 query
Answer: []dns.RR{&dns.A{
Hdr: dns.RR_Header{
Name: "tailscale.com.",
Rrtype: dns.TypeA,
Class: dns.ClassINET,
Ttl: 300,
},
A: net.IP(netip.MustParseAddr("13.248.141.131").AsSlice()),
}},
}},
},
},
}
r := &Resolver{
Logf: t.Logf,
testExchangeHook: mock.exchangeHook,
rootServers: []netip.Addr{rootServerAddr},
}
// Query for tailscale.com, verify we get no responses since the
// addresses are invalid.
_, _, err := r.Resolve(context.Background(), "tailscale.com")
if err == nil {
t.Fatalf("got no error, want error")
}
if !errors.Is(err, ErrAuthoritativeNoResponses) {
t.Fatalf("got err=%v, want %v", err, ErrAuthoritativeNoResponses)
}
}
// TODO(andrew): test for more edge cases that aren't currently covered:
// * Nameservers that cross between IPv4 and IPv6
// * Authoritative no replies after following CNAME
// * Authoritative no replies after following non-glue NS record
// * Error querying non-glue NS record followed by success