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package dns
import (
"fmt"
"io/ioutil"
"log"
"net"
"reflect"
"sync"
"testing"
"time"
"github.com/miekg/dns"
"github.com/mpolden/zdns/cache"
"github.com/mpolden/zdns/dns/dnsutil"
)
type dnsWriter struct{ lastReply *dns.Msg }
func (w *dnsWriter) LocalAddr() net.Addr { return nil }
func (w *dnsWriter) RemoteAddr() net.Addr {
return &net.UDPAddr{IP: net.IPv4(192, 0, 2, 100), Port: 50000}
}
func (w *dnsWriter) Write(b []byte) (int, error) { return 0, nil }
func (w *dnsWriter) Close() error { return nil }
func (w *dnsWriter) TsigStatus() error { return nil }
func (w *dnsWriter) TsigTimersOnly(b bool) {}
func (w *dnsWriter) Hijack() {}
func (w *dnsWriter) WriteMsg(msg *dns.Msg) error {
w.lastReply = msg
return nil
}
type response struct {
answer *dns.Msg
fail bool
}
type testExchanger struct {
mu sync.RWMutex
responses map[string]*response
}
func newTestExchanger() *testExchanger { return &testExchanger{responses: make(map[string]*response)} }
func (e *testExchanger) setResponse(resolver string, response *response) {
e.mu.Lock()
defer e.mu.Unlock()
e.responses[resolver] = response
}
func (e *testExchanger) Exchange(msg *dns.Msg, addr string) (*dns.Msg, time.Duration, error) {
e.mu.RLock()
defer e.mu.RUnlock()
r, ok := e.responses[addr]
if !ok {
panic("no such resolver: " + addr)
}
if r.fail {
return nil, 0, fmt.Errorf("%s SERVFAIL", addr)
}
return r.answer, time.Second, nil
}
type testLogger struct{}
func (l *testLogger) Record(net.IP, bool, uint16, string, ...string) {}
func (l *testLogger) Close() error { return nil }
func testProxy(t *testing.T) *Proxy {
logger := log.New(ioutil.Discard, "", 0)
dnsLogger := &testLogger{}
proxy, err := NewProxy(cache.New(0, nil), nil, logger, dnsLogger)
if err != nil {
t.Fatal(err)
}
return proxy
}
func assertRR(t *testing.T, p *Proxy, msg *dns.Msg, answer string) {
var (
qtype = msg.Question[0].Qtype
qname = msg.Question[0].Name
)
w := &dnsWriter{}
p.ServeDNS(w, msg)
qtypeString := dns.TypeToString[qtype]
answers := w.lastReply.Answer
if got, want := len(answers), 1; got != want {
t.Fatalf("len(msg.Answer) = %d, want %d for %s %s", got, want, qtypeString, qname)
}
ans := answers[0]
if got := w.lastReply.Id; got != msg.Id {
t.Errorf("id = %d, want %d for %s %s", got, msg.Id, qtypeString, qname)
}
want := net.ParseIP(answer)
var got net.IP
switch qtype {
case dns.TypeA:
rr, ok := ans.(*dns.A)
if !ok {
t.Errorf("type = %q, want %q for %s %s", dns.TypeToString[dns.TypeA], dns.TypeToString[rr.Header().Rrtype], qtypeString, qname)
}
got = rr.A
case dns.TypeAAAA:
rr, ok := ans.(*dns.AAAA)
if !ok {
t.Errorf("type = %q, want %q for %s %s", dns.TypeToString[dns.TypeA], dns.TypeToString[rr.Header().Rrtype], qtypeString, qname)
}
got = rr.AAAA
}
if !reflect.DeepEqual(got, want) {
t.Errorf("IP = %s, want %s", got, want)
}
}
func assertFailure(t *testing.T, p *Proxy, rtype uint16, qname string) {
m := dns.Msg{}
m.Id = dns.Id()
m.RecursionDesired = true
m.SetQuestion(dns.Fqdn(qname), rtype)
w := &dnsWriter{}
p.ServeDNS(w, &m)
if got, want := len(w.lastReply.Answer), 0; got != want {
t.Errorf("len(msg.Answer) = %d, want %d for %s %s", got, want, dns.TypeToString[rtype], qname)
}
if got, want := w.lastReply.MsgHdr.Rcode, dns.RcodeServerFailure; got != want {
t.Errorf("MsgHdr.Rcode = %s, want %s for %s %s", dns.RcodeToString[got], dns.RcodeToString[want], dns.TypeToString[rtype], qname)
}
}
func TestProxy(t *testing.T) {
var h Handler = func(r *Request) *Reply {
switch r.Type {
case TypeA:
return ReplyA(r.Name, net.IPv4zero)
case TypeAAAA:
return ReplyAAAA(r.Name, net.IPv6zero)
}
return nil
}
p := testProxy(t)
p.Handler = h
defer p.Close()
m := dns.Msg{}
m.Id = dns.Id()
m.RecursionDesired = true
m.SetQuestion(dns.Fqdn("badhost1"), dns.TypeA)
assertRR(t, p, &m, "0.0.0.0")
m.SetQuestion(dns.Fqdn("badhost1"), dns.TypeAAAA)
assertRR(t, p, &m, "::")
}
func TestProxyWithResolvers(t *testing.T) {
p := testProxy(t)
exchanger := newTestExchanger()
p.client = &dnsutil.Client{Exchanger: exchanger}
defer p.Close()
// No resolvers
assertFailure(t, p, TypeA, "host1")
// First and only resolver responds succesfully
p.client.Addresses = []string{"resolver1"}
reply := ReplyA("host1", net.ParseIP("192.0.2.1"))
m := dns.Msg{}
m.Id = dns.Id()
m.SetQuestion("host1.", dns.TypeA)
m.Answer = reply.rr
response1 := &response{answer: &m}
exchanger.setResponse("resolver1", response1)
assertRR(t, p, &m, "192.0.2.1")
// First and only resolver fails
response1.fail = true
assertFailure(t, p, TypeA, "host1")
// First resolver fails, but second succeeds
reply = ReplyA("host1", net.ParseIP("192.0.2.2"))
p.client.Addresses = []string{"resolver1", "resolver2"}
m = dns.Msg{}
m.Id = dns.Id()
m.SetQuestion("host1.", dns.TypeA)
m.Answer = reply.rr
response2 := &response{answer: &m}
exchanger.setResponse("resolver2", response2)
assertRR(t, p, &m, "192.0.2.2")
// All resolvers fail
response2.fail = true
assertFailure(t, p, TypeA, "host1")
}
func TestProxyWithCache(t *testing.T) {
p := testProxy(t)
p.cache = cache.New(10, nil)
exchanger := newTestExchanger()
p.client = &dnsutil.Client{Exchanger: exchanger}
p.client.Addresses = []string{"resolver1"}
defer p.Close()
reply := ReplyA("host1", net.ParseIP("192.0.2.1"))
m := dns.Msg{}
m.Id = dns.Id()
m.SetQuestion("host1.", dns.TypeA)
m.Answer = reply.rr
exchanger.setResponse("resolver1", &response{answer: &m})
assertRR(t, p, &m, "192.0.2.1")
k := cache.NewKey("host1.", dns.TypeA, dns.ClassINET)
got, ok := p.cache.Get(k)
if !ok {
t.Errorf("cache.Get(%d) = (%+v, %t), want (%+v, %t)", k, got, ok, m, !ok)
}
}
func TestReplyString(t *testing.T) {
var tests = []struct {
fn func(string, ...net.IP) *Reply
fnName string
name string
ipAddrs []net.IP
out string
}{
{ReplyA, "ReplyA", "test-host", []net.IP{net.ParseIP("192.0.2.1")},
"test-host\t3600\tIN\tA\t192.0.2.1"},
{ReplyA, "ReplyA", "test-host", []net.IP{net.ParseIP("192.0.2.1"), net.ParseIP("192.0.2.2")},
"test-host\t3600\tIN\tA\t192.0.2.1\ntest-host\t3600\tIN\tA\t192.0.2.2"},
{ReplyAAAA, "ReplyAAAA", "test-host", []net.IP{net.ParseIP("2001:db8::1")},
"test-host\t3600\tIN\tAAAA\t2001:db8::1"},
{ReplyAAAA, "ReplyAAAA", "test-host", []net.IP{net.ParseIP("2001:db8::1"), net.ParseIP("2001:db8::2")},
"test-host\t3600\tIN\tAAAA\t2001:db8::1\ntest-host\t3600\tIN\tAAAA\t2001:db8::2"},
}
for i, tt := range tests {
got := tt.fn(tt.name, tt.ipAddrs...).String()
if got != tt.out {
t.Errorf("#%d: %s(%q, %v) = %q, want %q", i, tt.fnName, tt.name, tt.ipAddrs, got, tt.out)
}
}
}
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