1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
|
package dns
import (
"fmt"
"io/ioutil"
"net"
"reflect"
"sync"
"testing"
"time"
"github.com/miekg/dns"
"github.com/mpolden/zdns/cache"
"github.com/mpolden/zdns/dns/dnsutil"
"github.com/mpolden/zdns/log"
)
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
}
func testProxy(t *testing.T) *Proxy {
log, err := log.New(ioutil.Discard, "", log.RecordOptions{})
if err != nil {
t.Fatal(err)
}
if err != nil {
t.Fatal(err)
}
proxy, err := NewProxy(cache.New(0, nil), nil, log)
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)
}
}
}
|