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// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause
package main
import (
"bytes"
"encoding/json"
"io"
"net"
"net/http"
"net/http/httptest"
"net/netip"
"net/url"
"reflect"
"testing"
"tailscale.com/tstest"
"tailscale.com/tstest/nettest"
)
func BenchmarkHandleBootstrapDNS(b *testing.B) {
tstest.Replace(b, bootstrapDNS, "log.tailscale.com,login.tailscale.com,controlplane.tailscale.com,login.us.tailscale.com")
refreshBootstrapDNS()
w := new(bitbucketResponseWriter)
req, _ := http.NewRequest("GET", "https://localhost/bootstrap-dns?q="+url.QueryEscape("log.tailscale.com"), nil)
b.ReportAllocs()
b.ResetTimer()
b.RunParallel(func(b *testing.PB) {
for b.Next() {
handleBootstrapDNS(w, req)
}
})
}
type bitbucketResponseWriter struct{}
func (b *bitbucketResponseWriter) Header() http.Header { return make(http.Header) }
func (b *bitbucketResponseWriter) Write(p []byte) (int, error) { return len(p), nil }
func (b *bitbucketResponseWriter) WriteHeader(statusCode int) {}
func getBootstrapDNS(t *testing.T, q string) map[string][]net.IP {
t.Helper()
req, _ := http.NewRequest("GET", "https://localhost/bootstrap-dns?q="+url.QueryEscape(q), nil)
w := httptest.NewRecorder()
handleBootstrapDNS(w, req)
res := w.Result()
if res.StatusCode != 200 {
t.Fatalf("got status=%d; want %d", res.StatusCode, 200)
}
var m map[string][]net.IP
var buf bytes.Buffer
if err := json.NewDecoder(io.TeeReader(res.Body, &buf)).Decode(&m); err != nil {
t.Fatalf("error decoding response body %q: %v", buf.Bytes(), err)
}
return m
}
func TestUnpublishedDNS(t *testing.T) {
nettest.SkipIfNoNetwork(t)
const published = "login.tailscale.com"
const unpublished = "log.tailscale.com"
prev1, prev2 := *bootstrapDNS, *unpublishedDNS
*bootstrapDNS = published
*unpublishedDNS = unpublished
t.Cleanup(func() {
*bootstrapDNS = prev1
*unpublishedDNS = prev2
})
refreshBootstrapDNS()
refreshUnpublishedDNS()
hasResponse := func(q string) bool {
_, found := getBootstrapDNS(t, q)[q]
return found
}
if !hasResponse(published) {
t.Errorf("expected response for: %s", published)
}
if !hasResponse(unpublished) {
t.Errorf("expected response for: %s", unpublished)
}
// Verify that querying for a random query or a real query does not
// leak our unpublished domain
m1 := getBootstrapDNS(t, published)
if _, found := m1[unpublished]; found {
t.Errorf("found unpublished domain %s: %+v", unpublished, m1)
}
m2 := getBootstrapDNS(t, "random.example.com")
if _, found := m2[unpublished]; found {
t.Errorf("found unpublished domain %s: %+v", unpublished, m2)
}
}
func resetMetrics() {
publishedDNSHits.Set(0)
publishedDNSMisses.Set(0)
unpublishedDNSHits.Set(0)
unpublishedDNSMisses.Set(0)
bootstrapLookupMap.Clear()
}
// Verify that we don't count an empty list in the unpublishedDNSCache as a
// cache hit in our metrics.
func TestUnpublishedDNSEmptyList(t *testing.T) {
pub := &dnsEntryMap{
IPs: map[string][]net.IP{"tailscale.com": {net.IPv4(10, 10, 10, 10)}},
}
dnsCache.Store(pub)
dnsCacheBytes.Store([]byte(`{"tailscale.com":["10.10.10.10"]}`))
unpublishedDNSCache.Store(&dnsEntryMap{
IPs: map[string][]net.IP{
"log.tailscale.com": {},
"controlplane.tailscale.com": {net.IPv4(1, 2, 3, 4)},
},
Percent: map[string]float64{
"log.tailscale.com": 1.0,
"controlplane.tailscale.com": 1.0,
},
})
t.Run("CacheMiss", func(t *testing.T) {
// One domain in map but empty, one not in map at all
for _, q := range []string{"log.tailscale.com", "login.tailscale.com"} {
resetMetrics()
ips := getBootstrapDNS(t, q)
// Expected our public map to be returned on a cache miss
if !reflect.DeepEqual(ips, pub.IPs) {
t.Errorf("got ips=%+v; want %+v", ips, pub.IPs)
}
if v := unpublishedDNSHits.Value(); v != 0 {
t.Errorf("got hits=%d; want 0", v)
}
if v := unpublishedDNSMisses.Value(); v != 1 {
t.Errorf("got misses=%d; want 1", v)
}
}
})
// Verify that we do get a valid response and metric.
t.Run("CacheHit", func(t *testing.T) {
resetMetrics()
ips := getBootstrapDNS(t, "controlplane.tailscale.com")
want := map[string][]net.IP{"controlplane.tailscale.com": {net.IPv4(1, 2, 3, 4)}}
if !reflect.DeepEqual(ips, want) {
t.Errorf("got ips=%+v; want %+v", ips, want)
}
if v := unpublishedDNSHits.Value(); v != 1 {
t.Errorf("got hits=%d; want 1", v)
}
if v := unpublishedDNSMisses.Value(); v != 0 {
t.Errorf("got misses=%d; want 0", v)
}
})
}
func TestLookupMetric(t *testing.T) {
d := []string{"a.io", "b.io", "c.io", "d.io", "e.io", "e.io", "e.io", "a.io"}
resetMetrics()
for _, q := range d {
_ = getBootstrapDNS(t, q)
}
// {"a.io": true, "b.io": true, "c.io": true, "d.io": true, "e.io": true}
if bootstrapLookupMap.Len() != 5 {
t.Errorf("bootstrapLookupMap.Len() want=5, got %v", bootstrapLookupMap.Len())
}
}
func TestRemoteAddrMatchesPercent(t *testing.T) {
tests := []struct {
remoteAddr string
percent float64
want bool
}{
// 0% and 100%.
{"10.0.0.1:1234", 0.0, false},
{"10.0.0.1:1234", 1.0, true},
// Invalid IP.
{"", 1.0, true},
{"", 0.0, false},
{"", 0.5, false},
// Small manual sample at 50%. The func uses a deterministic PRNG seed.
{"1.2.3.4:567", 0.5, true},
{"1.2.3.5:567", 0.5, true},
{"1.2.3.6:567", 0.5, false},
{"1.2.3.7:567", 0.5, true},
{"1.2.3.8:567", 0.5, false},
{"1.2.3.9:567", 0.5, true},
{"1.2.3.10:567", 0.5, true},
}
for _, tt := range tests {
got := remoteAddrMatchesPercent(tt.remoteAddr, tt.percent)
if got != tt.want {
t.Errorf("remoteAddrMatchesPercent(%q, %v) = %v; want %v", tt.remoteAddr, tt.percent, got, tt.want)
}
}
var match, all int
const wantPercent = 0.5
for a := range 256 {
for b := range 256 {
all++
if remoteAddrMatchesPercent(
netip.AddrPortFrom(netip.AddrFrom4([4]byte{1, 2, byte(a), byte(b)}), 12345).String(),
wantPercent) {
match++
}
}
}
gotPercent := float64(match) / float64(all)
const tolerance = 0.005
t.Logf("got percent %v (goal %v)", gotPercent, wantPercent)
if gotPercent < wantPercent-tolerance || gotPercent > wantPercent+tolerance {
t.Errorf("got %v; want %v ± %v", gotPercent, wantPercent, tolerance)
}
}
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