66942bd4f7
There is not much of a difference between IPv4 and IPv6 on my fiber7 link, but in other networks, there might well be. For my connection, this commit results in hitting different upstreams all the time because the list isn’t stable. But, this is the opposite of a problem: we are spreading the DNS query load over all configured IPs, as good netizen do.
531 lines
15 KiB
Go
531 lines
15 KiB
Go
// Copyright 2018 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package dns
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import (
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"bytes"
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"fmt"
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"io/ioutil"
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"net"
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"net/http"
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"net/http/httptest"
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"net/url"
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"os"
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"strings"
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"sync/atomic"
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"testing"
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"time"
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"github.com/rtr7/router7/internal/dhcp4d"
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"github.com/miekg/dns"
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)
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// TODO(later): upstream a dnstest.Recorder implementation
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type recorder struct {
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response *dns.Msg
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}
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func (r *recorder) WriteMsg(m *dns.Msg) error {
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r.response = m
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return nil
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}
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func (r *recorder) LocalAddr() net.Addr { return nil }
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func (r *recorder) RemoteAddr() net.Addr { return nil }
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func (r *recorder) Write([]byte) (int, error) { return 0, nil }
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func (r *recorder) Close() error { return nil }
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func (r *recorder) TsigStatus() error { return nil }
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func (r *recorder) TsigTimersOnly(bool) {}
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func (r *recorder) Hijack() {}
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func TestNXDOMAIN(t *testing.T) {
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r := &recorder{}
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s := NewServer("localhost:0", "lan")
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m := new(dns.Msg)
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m.SetQuestion("foo.invalid.", dns.TypeA)
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s.Mux.ServeDNS(r, m)
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if got, want := r.response.MsgHdr.Rcode, dns.RcodeNameError; got != want {
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t.Fatalf("unexpected rcode: got %v, want %v", got, want)
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}
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}
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func TestResolveError(t *testing.T) {
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r := &recorder{}
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s := NewServer("localhost:0", "lan")
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s.upstream = []string{"266.266.266.266:53"}
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m := new(dns.Msg)
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m.SetQuestion("foo.invalid.", dns.TypeA)
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s.Mux.ServeDNS(r, m)
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if r.response != nil {
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t.Fatalf("r.response unexpectedly not nil: %v", r.response)
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}
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}
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func TestResolveFallback(t *testing.T) {
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s := NewServer("localhost:0", "lan")
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s.upstream = []string{
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"266.266.266.266:53",
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dnsServerAddr(t, dns.HandlerFunc(func(w dns.ResponseWriter, r *dns.Msg) {
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reply(w, r, " 3600 IN A 127.0.0.1")
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})),
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}
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if err := resolveTestTarget(s, "google.ch.", net.ParseIP("127.0.0.1")); err != nil {
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t.Fatal(err)
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}
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}
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func dnsServerAddr(t *testing.T, h dns.Handler) string {
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t.Helper()
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pc, err := net.ListenPacket("udp", "localhost:0")
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if err != nil {
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t.Fatal(err)
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}
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go dns.ActivateAndServe(nil, pc, h)
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return pc.LocalAddr().String()
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}
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func TestResolveFallbackOnce(t *testing.T) {
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s := NewServer("localhost:0", "lan")
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var slowHits uint32
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s.upstream = []string{
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dnsServerAddr(t, dns.HandlerFunc(func(w dns.ResponseWriter, r *dns.Msg) {
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atomic.AddUint32(&slowHits, 1)
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// trigger fallback by sending no reply
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})),
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dnsServerAddr(t, dns.HandlerFunc(func(w dns.ResponseWriter, r *dns.Msg) {
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reply(w, r, " 3600 IN A 127.0.0.1")
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})),
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"266.266.266.266:53",
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}
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for i := 0; i < 2; i++ {
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if err := resolveTestTarget(s, "google.ch.", net.ParseIP("127.0.0.1")); err != nil {
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t.Fatal(err)
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}
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}
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if got, want := atomic.LoadUint32(&slowHits), uint32(1); got != want {
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t.Errorf("slow upstream server hits = %d, wanted %d", got, want)
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}
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}
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func reply(w dns.ResponseWriter, r *dns.Msg, response string) {
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rr, _ := dns.NewRR(r.Question[0].Name + response)
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m := new(dns.Msg)
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m.SetReply(r)
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m.Answer = append(m.Answer, rr)
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w.WriteMsg(m)
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}
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func TestResolveLatencySteering(t *testing.T) {
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s := NewServer("localhost:0", "lan")
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var slowHits uint32
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s.upstream = []string{
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dnsServerAddr(t, dns.HandlerFunc(func(w dns.ResponseWriter, r *dns.Msg) {
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atomic.AddUint32(&slowHits, 1)
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time.Sleep(10 * time.Millisecond)
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reply(w, r, " 3600 IN A 127.0.0.1")
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})),
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dnsServerAddr(t, dns.HandlerFunc(func(w dns.ResponseWriter, r *dns.Msg) {
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reply(w, r, " 3600 IN A 127.0.0.1")
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})),
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"266.266.266.266:53",
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}
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if err := resolveTestTarget(s, "google.ch.", net.ParseIP("127.0.0.1")); err != nil {
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t.Fatal(err)
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}
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s.probeUpstreamLatency()
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if err := resolveTestTarget(s, "google.ch.", net.ParseIP("127.0.0.1")); err != nil {
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t.Fatal(err)
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}
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want := uint32(2) // one for resolving, one for probing
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if got := atomic.LoadUint32(&slowHits); got != want {
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t.Errorf("slow upstream server hits = %d, wanted %d", got, want)
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}
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}
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func TestDHCP(t *testing.T) {
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r := &recorder{}
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s := NewServer("localhost:0", "lan")
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s.SetLeases([]dhcp4d.Lease{
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{
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Hostname: "testtarget",
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Addr: net.IP{192, 168, 42, 23},
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},
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})
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t.Run("testtarget.lan.", func(t *testing.T) {
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if err := resolveTestTarget(s, "testtarget.lan.", net.ParseIP("192.168.42.23")); err != nil {
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t.Fatal(err)
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}
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})
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expired := time.Now().Add(-1 * time.Second)
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s.SetLeases([]dhcp4d.Lease{
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{
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Hostname: "testtarget",
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Addr: net.IP{192, 168, 42, 23},
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Expiry: time.Now().Add(1 * time.Minute),
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},
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{
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Hostname: "testtarget",
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Addr: net.IP{192, 168, 42, 150},
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Expiry: expired,
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},
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})
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t.Run("testtarget.lan. (expired)", func(t *testing.T) {
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if err := resolveTestTarget(s, "testtarget.lan.", net.ParseIP("192.168.42.23")); err != nil {
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t.Fatal(err)
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}
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})
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t.Run("notfound.lan.", func(t *testing.T) {
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m := new(dns.Msg)
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m.SetQuestion("notfound.lan.", dns.TypeA)
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s.Mux.ServeDNS(r, m)
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if got, want := r.response.Rcode, dns.RcodeNameError; got != want {
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t.Fatalf("unexpected rcode: got %v, want %v", got, want)
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}
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})
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}
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func TestHostname(t *testing.T) {
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hostname, err := os.Hostname()
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if err != nil {
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t.Skipf("os.Hostname: %v", err)
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}
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r := &recorder{}
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s := NewServer("127.0.0.2:0", "lan")
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s.SetLeases([]dhcp4d.Lease{
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{
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Hostname: hostname,
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Addr: net.IP{192, 168, 42, 23},
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},
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})
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t.Run("A", func(t *testing.T) {
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m := new(dns.Msg)
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m.SetQuestion(hostname+".lan.", dns.TypeA)
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s.Mux.ServeDNS(r, m)
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if got, want := len(r.response.Answer), 1; got != want {
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t.Fatalf("unexpected number of answers for %v: got %d, want %d", m.Question, got, want)
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}
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a := r.response.Answer[0]
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if _, ok := a.(*dns.A); !ok {
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t.Fatalf("unexpected response type: got %T, want dns.A", a)
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}
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if got, want := a.(*dns.A).A, net.ParseIP("127.0.0.2"); !got.Equal(want) {
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t.Fatalf("unexpected response IP: got %v, want %v", got, want)
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}
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})
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t.Run("PTR", func(t *testing.T) {
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m := new(dns.Msg)
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m.SetQuestion("2.0.0.127.in-addr.arpa.", dns.TypePTR)
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s.Mux.ServeDNS(r, m)
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if got, want := len(r.response.Answer), 1; got != want {
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t.Fatalf("unexpected number of answers: got %d, want %d", got, want)
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}
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a := r.response.Answer[0]
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if _, ok := a.(*dns.PTR); !ok {
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t.Fatalf("unexpected response type: got %T, want dns.PTR", a)
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}
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if got, want := a.(*dns.PTR).Ptr, hostname+".lan."; got != want {
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t.Fatalf("unexpected response record: got %q, want %q", got, want)
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}
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})
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}
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func TestHostnameDHCP(t *testing.T) {
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hostname, err := os.Hostname()
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if err != nil {
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t.Skipf("os.Hostname: %v", err)
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}
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r := &recorder{}
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s := NewServer("127.0.0.2:0", "lan")
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t.Run("A", func(t *testing.T) {
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m := new(dns.Msg)
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m.SetQuestion(hostname+".lan.", dns.TypeA)
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s.Mux.ServeDNS(r, m)
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if got, want := len(r.response.Answer), 1; got != want {
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t.Fatalf("unexpected number of answers for %v: got %d, want %d", m.Question, got, want)
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}
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a := r.response.Answer[0]
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if _, ok := a.(*dns.A); !ok {
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t.Fatalf("unexpected response type: got %T, want dns.A", a)
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}
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if got, want := a.(*dns.A).A, net.ParseIP("127.0.0.2"); !got.Equal(want) {
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t.Fatalf("unexpected response IP: got %v, want %v", got, want)
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}
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})
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t.Run("PTR", func(t *testing.T) {
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m := new(dns.Msg)
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m.SetQuestion("2.0.0.127.in-addr.arpa.", dns.TypePTR)
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s.Mux.ServeDNS(r, m)
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if got, want := len(r.response.Answer), 1; got != want {
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t.Fatalf("unexpected number of answers: got %d, want %d", got, want)
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}
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a := r.response.Answer[0]
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if _, ok := a.(*dns.PTR); !ok {
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t.Fatalf("unexpected response type: got %T, want dns.PTR", a)
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}
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if got, want := a.(*dns.PTR).Ptr, hostname+".lan."; got != want {
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t.Fatalf("unexpected response record: got %q, want %q", got, want)
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}
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})
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t.Run("AAAA", func(t *testing.T) {
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m := new(dns.Msg)
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m.SetQuestion(hostname+".lan.", dns.TypeAAAA)
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s.Mux.ServeDNS(r, m)
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if got, want := r.response.MsgHdr.Rcode, dns.RcodeSuccess; got != want {
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t.Fatalf("unexpected rcode: got %v, want %v", got, want)
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}
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if got, want := len(r.response.Answer), 0; got != want {
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t.Fatalf("unexpected number of answers: got %d, want %d", got, want)
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}
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})
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}
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func TestLocalhost(t *testing.T) {
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r := &recorder{}
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s := NewServer("127.0.0.2:0", "lan")
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t.Run("A", func(t *testing.T) {
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m := new(dns.Msg)
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m.SetQuestion("localhost.", dns.TypeA)
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s.Mux.ServeDNS(r, m)
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if got, want := len(r.response.Answer), 1; got != want {
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t.Fatalf("unexpected number of answers for %v: got %d, want %d", m.Question, got, want)
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}
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a := r.response.Answer[0]
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if _, ok := a.(*dns.A); !ok {
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t.Fatalf("unexpected response type: got %T, want dns.A", a)
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}
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if got, want := a.(*dns.A).A, net.ParseIP("127.0.0.1"); !got.Equal(want) {
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t.Fatalf("unexpected response IP: got %v, want %v", got, want)
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}
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})
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t.Run("AAAA", func(t *testing.T) {
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m := new(dns.Msg)
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m.SetQuestion("localhost.", dns.TypeAAAA)
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s.Mux.ServeDNS(r, m)
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if got, want := len(r.response.Answer), 1; got != want {
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t.Fatalf("unexpected number of answers for %v: got %d, want %d", m.Question, got, want)
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}
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a := r.response.Answer[0]
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if _, ok := a.(*dns.AAAA); !ok {
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t.Fatalf("unexpected response type: got %T, want dns.A", a)
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}
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if got, want := a.(*dns.AAAA).AAAA, (net.ParseIP("::1")); !bytes.Equal(got, want) {
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t.Fatalf("unexpected response IP: got %v, want %v", got, want)
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}
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})
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t.Run("PTR", func(t *testing.T) {
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m := new(dns.Msg)
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m.SetQuestion("1.0.0.127.in-addr.arpa.", dns.TypePTR)
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s.Mux.ServeDNS(r, m)
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if got, want := len(r.response.Answer), 1; got != want {
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t.Fatalf("unexpected number of answers: got %d, want %d", got, want)
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}
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a := r.response.Answer[0]
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if _, ok := a.(*dns.PTR); !ok {
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t.Fatalf("unexpected response type: got %T, want dns.PTR", a)
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}
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if got, want := a.(*dns.PTR).Ptr, "localhost."; got != want {
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t.Fatalf("unexpected response record: got %q, want %q", got, want)
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}
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})
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}
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func TestDHCPReverse(t *testing.T) {
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for _, test := range []struct {
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ip net.IP
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question string
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}{
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{
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ip: net.IP{192, 168, 42, 23},
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question: "23.42.168.192.in-addr.arpa.",
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},
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{
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ip: net.IP{10, 0, 0, 2},
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question: "2.0.0.10.in-addr.arpa.",
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},
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{
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ip: net.IP{172, 16, 0, 1}, // 172.16/12 HostMin
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question: "1.0.16.172.in-addr.arpa.",
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},
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{
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ip: net.IP{172, 31, 255, 254}, // 172.16/12 HostMax
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question: "254.255.31.172.in-addr.arpa.",
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},
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} {
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t.Run(test.question, func(t *testing.T) {
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r := &recorder{}
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s := NewServer("localhost:0", "lan")
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s.SetLeases([]dhcp4d.Lease{
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{
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Hostname: "testtarget",
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Addr: test.ip,
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},
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})
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m := new(dns.Msg)
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m.SetQuestion(test.question, dns.TypePTR)
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s.Mux.ServeDNS(r, m)
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if got, want := len(r.response.Answer), 1; got != want {
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t.Fatalf("unexpected number of answers: got %d, want %d", got, want)
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}
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a := r.response.Answer[0]
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if _, ok := a.(*dns.PTR); !ok {
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t.Fatalf("unexpected response type: got %T, want dns.PTR", a)
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}
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if got, want := a.(*dns.PTR).Ptr, "testtarget.lan."; got != want {
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t.Fatalf("unexpected response record: got %q, want %q", got, want)
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}
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})
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}
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t.Run("no leases", func(t *testing.T) {
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r := &recorder{}
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s := NewServer("localhost:0", "lan")
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m := new(dns.Msg)
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m.SetQuestion("254.255.31.172.in-addr.arpa.", dns.TypePTR)
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s.Mux.ServeDNS(r, m)
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if got, want := r.response.Rcode, dns.RcodeNameError; got != want {
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t.Fatalf("unexpected rcode: got %v, want %v", got, want)
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}
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})
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}
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func resolveTestTarget(s *Server, name string, want net.IP) error {
|
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m := new(dns.Msg)
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typ := dns.TypeA
|
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if want.To4() == nil {
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typ = dns.TypeAAAA
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}
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m.SetQuestion(name, typ)
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r := &recorder{}
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s.Mux.ServeDNS(r, m)
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if r.response == nil {
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return fmt.Errorf("nil response")
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}
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if got, want := len(r.response.Answer), 1; got != want {
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return fmt.Errorf("unexpected number of answers: got %d, want %d", got, want)
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}
|
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a := r.response.Answer[0]
|
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if typ == dns.TypeA {
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if _, ok := a.(*dns.A); !ok {
|
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return fmt.Errorf("unexpected response type: got %T, want dns.A", a)
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}
|
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if got := a.(*dns.A).A; !got.Equal(want) {
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return fmt.Errorf("unexpected response IP: got %v, want %v", got, want)
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}
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} else {
|
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if _, ok := a.(*dns.AAAA); !ok {
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return fmt.Errorf("unexpected response type: got %T, want dns.A", a)
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}
|
|
if got := a.(*dns.AAAA).AAAA; !got.Equal(want) {
|
|
return fmt.Errorf("unexpected response IP: got %v, want %v", got, want)
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// TODO: multiple questions
|
|
|
|
func TestSubname(t *testing.T) {
|
|
r := &recorder{}
|
|
s := NewServer("127.0.0.2:0", "lan")
|
|
s.SetLeases([]dhcp4d.Lease{
|
|
{
|
|
Hostname: "testtarget",
|
|
Addr: net.IP{192, 168, 42, 23},
|
|
},
|
|
})
|
|
|
|
t.Run("testtarget.lan.", func(t *testing.T) {
|
|
if err := resolveTestTarget(s, "testtarget.lan.", net.ParseIP("192.168.42.23")); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
})
|
|
|
|
t.Run("sub.testtarget.lan.", func(t *testing.T) {
|
|
m := new(dns.Msg)
|
|
m.SetQuestion("notfound.lan.", dns.TypeA)
|
|
s.Mux.ServeDNS(r, m)
|
|
if got, want := r.response.Rcode, dns.RcodeNameError; got != want {
|
|
t.Fatalf("unexpected rcode: got %v, want %v", got, want)
|
|
}
|
|
})
|
|
|
|
setSubname := func(ip, remoteAddr string) {
|
|
val := url.Values{
|
|
"host": []string{"sub"},
|
|
"ip": []string{ip},
|
|
}
|
|
req := httptest.NewRequest("POST", "/dyndns", strings.NewReader(val.Encode()))
|
|
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
|
|
req.RemoteAddr = remoteAddr
|
|
rec := httptest.NewRecorder()
|
|
s.DyndnsHandler(rec, req)
|
|
resp := rec.Result()
|
|
if got, want := resp.StatusCode, http.StatusOK; got != want {
|
|
body, _ := ioutil.ReadAll(resp.Body)
|
|
t.Fatalf("POST /dyndns: unexpected HTTP status: got %v, want %v (%q)", resp.Status, want, string(body))
|
|
}
|
|
}
|
|
const ip = "fdf5:3606:2a21:1341:b26e:bfff:fe30:504b"
|
|
setSubname(ip, "192.168.42.23:1234")
|
|
|
|
for _, name := range []string{
|
|
"sub.testtarget.lan.",
|
|
"sub.testtarget.",
|
|
} {
|
|
t.Run(name+" (after dyndns)", func(t *testing.T) {
|
|
if err := resolveTestTarget(s, name, net.ParseIP(ip)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
})
|
|
}
|
|
|
|
t.Run("Hostname", func(t *testing.T) {
|
|
hostname, err := os.Hostname()
|
|
if err != nil {
|
|
t.Skipf("os.Hostname: %v", err)
|
|
}
|
|
if err := resolveTestTarget(s, hostname+".lan.", net.ParseIP("127.0.0.2")); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
setSubname(ip, "127.0.0.2:1234")
|
|
if err := resolveTestTarget(s, "sub."+hostname+".lan.", net.ParseIP(ip)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
})
|
|
}
|