aboutsummaryrefslogtreecommitdiffstats
path: root/p2p/discover/udp_test.go
blob: 8bca37ffedaafd8bb7f1a6594a29ebce3c4b843f (plain) (blame)
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
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package discover

import (
    "bytes"
    "crypto/ecdsa"
    "encoding/binary"
    "encoding/hex"
    "errors"
    "fmt"
    "io"
    "math/rand"
    "net"
    "path/filepath"
    "reflect"
    "runtime"
    "sync"
    "testing"
    "time"

    "github.com/davecgh/go-spew/spew"
    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/rlp"
)

func init() {
    spew.Config.DisableMethods = true
}

// shared test variables
var (
    futureExp          = uint64(time.Now().Add(10 * time.Hour).Unix())
    testTarget         = NodeID{0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1}
    testRemote         = rpcEndpoint{IP: net.ParseIP("1.1.1.1").To4(), UDP: 1, TCP: 2}
    testLocalAnnounced = rpcEndpoint{IP: net.ParseIP("2.2.2.2").To4(), UDP: 3, TCP: 4}
    testLocal          = rpcEndpoint{IP: net.ParseIP("3.3.3.3").To4(), UDP: 5, TCP: 6}
)

type udpTest struct {
    t                   *testing.T
    pipe                *dgramPipe
    table               *Table
    udp                 *udp
    sent                [][]byte
    localkey, remotekey *ecdsa.PrivateKey
    remoteaddr          *net.UDPAddr
}

func newUDPTest(t *testing.T) *udpTest {
    test := &udpTest{
        t:          t,
        pipe:       newpipe(),
        localkey:   newkey(),
        remotekey:  newkey(),
        remoteaddr: &net.UDPAddr{IP: net.IP{10, 0, 1, 99}, Port: 30303},
    }
    test.table, test.udp, _ = newUDP(test.localkey, test.pipe, nil, "", nil)
    return test
}

// handles a packet as if it had been sent to the transport.
func (test *udpTest) packetIn(wantError error, ptype byte, data packet) error {
    enc, err := encodePacket(test.remotekey, ptype, data)
    if err != nil {
        return test.errorf("packet (%d) encode error: %v", ptype, err)
    }
    test.sent = append(test.sent, enc)
    if err = test.udp.handlePacket(test.remoteaddr, enc); err != wantError {
        return test.errorf("error mismatch: got %q, want %q", err, wantError)
    }
    return nil
}

// waits for a packet to be sent by the transport.
// validate should have type func(*udpTest, X) error, where X is a packet type.
func (test *udpTest) waitPacketOut(validate interface{}) error {
    dgram := test.pipe.waitPacketOut()
    p, _, _, err := decodePacket(dgram)
    if err != nil {
        return test.errorf("sent packet decode error: %v", err)
    }
    fn := reflect.ValueOf(validate)
    exptype := fn.Type().In(0)
    if reflect.TypeOf(p) != exptype {
        return test.errorf("sent packet type mismatch, got: %v, want: %v", reflect.TypeOf(p), exptype)
    }
    fn.Call([]reflect.Value{reflect.ValueOf(p)})
    return nil
}

func (test *udpTest) errorf(format string, args ...interface{}) error {
    _, file, line, ok := runtime.Caller(2) // errorf + waitPacketOut
    if ok {
        file = filepath.Base(file)
    } else {
        file = "???"
        line = 1
    }
    err := fmt.Errorf(format, args...)
    fmt.Printf("\t%s:%d: %v\n", file, line, err)
    test.t.Fail()
    return err
}

func TestUDP_packetErrors(t *testing.T) {
    test := newUDPTest(t)
    defer test.table.Close()

    test.packetIn(errExpired, pingPacket, &ping{From: testRemote, To: testLocalAnnounced, Version: Version})
    test.packetIn(errUnsolicitedReply, pongPacket, &pong{ReplyTok: []byte{}, Expiration: futureExp})
    test.packetIn(errUnknownNode, findnodePacket, &findnode{Expiration: futureExp})
    test.packetIn(errUnsolicitedReply, neighborsPacket, &neighbors{Expiration: futureExp})
}

func TestUDP_pingTimeout(t *testing.T) {
    t.Parallel()
    test := newUDPTest(t)
    defer test.table.Close()

    toaddr := &net.UDPAddr{IP: net.ParseIP("1.2.3.4"), Port: 2222}
    toid := NodeID{1, 2, 3, 4}
    if err := test.udp.ping(toid, toaddr); err != errTimeout {
        t.Error("expected timeout error, got", err)
    }
}

func TestUDP_responseTimeouts(t *testing.T) {
    t.Parallel()
    test := newUDPTest(t)
    defer test.table.Close()

    rand.Seed(time.Now().UnixNano())
    randomDuration := func(max time.Duration) time.Duration {
        return time.Duration(rand.Int63n(int64(max)))
    }

    var (
        nReqs      = 200
        nTimeouts  = 0                       // number of requests with ptype > 128
        nilErr     = make(chan error, nReqs) // for requests that get a reply
        timeoutErr = make(chan error, nReqs) // for requests that time out
    )
    for i := 0; i < nReqs; i++ {
        // Create a matcher for a random request in udp.loop. Requests
        // with ptype <= 128 will not get a reply and should time out.
        // For all other requests, a reply is scheduled to arrive
        // within the timeout window.
        p := &pending{
            ptype:    byte(rand.Intn(255)),
            callback: func(interface{}) bool { return true },
        }
        binary.BigEndian.PutUint64(p.from[:], uint64(i))
        if p.ptype <= 128 {
            p.errc = timeoutErr
            test.udp.addpending <- p
            nTimeouts++
        } else {
            p.errc = nilErr
            test.udp.addpending <- p
            time.AfterFunc(randomDuration(60*time.Millisecond), func() {
                if !test.udp.handleReply(p.from, p.ptype, nil) {
                    t.Logf("not matched: %v", p)
                }
            })
        }
        time.Sleep(randomDuration(30 * time.Millisecond))
    }

    // Check that all timeouts were delivered and that the rest got nil errors.
    // The replies must be delivered.
    var (
        recvDeadline        = time.After(20 * time.Second)
        nTimeoutsRecv, nNil = 0, 0
    )
    for i := 0; i < nReqs; i++ {
        select {
        case err := <-timeoutErr:
            if err != errTimeout {
                t.Fatalf("got non-timeout error on timeoutErr %d: %v", i, err)
            }
            nTimeoutsRecv++
        case err := <-nilErr:
            if err != nil {
                t.Fatalf("got non-nil error on nilErr %d: %v", i, err)
            }
            nNil++
        case <-recvDeadline:
            t.Fatalf("exceeded recv deadline")
        }
    }
    if nTimeoutsRecv != nTimeouts {
        t.Errorf("wrong number of timeout errors received: got %d, want %d", nTimeoutsRecv, nTimeouts)
    }
    if nNil != nReqs-nTimeouts {
        t.Errorf("wrong number of successful replies: got %d, want %d", nNil, nReqs-nTimeouts)
    }
}

func TestUDP_findnodeTimeout(t *testing.T) {
    t.Parallel()
    test := newUDPTest(t)
    defer test.table.Close()

    toaddr := &net.UDPAddr{IP: net.ParseIP("1.2.3.4"), Port: 2222}
    toid := NodeID{1, 2, 3, 4}
    target := NodeID{4, 5, 6, 7}
    result, err := test.udp.findnode(toid, toaddr, target)
    if err != errTimeout {
        t.Error("expected timeout error, got", err)
    }
    if len(result) > 0 {
        t.Error("expected empty result, got", result)
    }
}

func TestUDP_findnode(t *testing.T) {
    test := newUDPTest(t)
    defer test.table.Close()

    // put a few nodes into the table. their exact
    // distribution shouldn't matter much, altough we need to
    // take care not to overflow any bucket.
    targetHash := crypto.Keccak256Hash(testTarget[:])
    nodes := &nodesByDistance{target: targetHash}
    for i := 0; i < bucketSize; i++ {
        nodes.push(nodeAtDistance(test.table.self.sha, i+2), bucketSize)
    }
    test.table.stuff(nodes.entries)

    // ensure there's a bond with the test node,
    // findnode won't be accepted otherwise.
    test.table.db.updateNode(NewNode(
        PubkeyID(&test.remotekey.PublicKey),
        test.remoteaddr.IP,
        uint16(test.remoteaddr.Port),
        99,
    ))
    // check that closest neighbors are returned.
    test.packetIn(nil, findnodePacket, &findnode{Target: testTarget, Expiration: futureExp})
    expected := test.table.closest(targetHash, bucketSize)

    waitNeighbors := func(want []*Node) {
        test.waitPacketOut(func(p *neighbors) {
            if len(p.Nodes) != len(want) {
                t.Errorf("wrong number of results: got %d, want %d", len(p.Nodes), bucketSize)
            }
            for i := range p.Nodes {
                if p.Nodes[i].ID != want[i].ID {
                    t.Errorf("result mismatch at %d:\n  got:  %v\n  want: %v", i, p.Nodes[i], expected.entries[i])
                }
            }
        })
    }
    waitNeighbors(expected.entries[:maxNeighbors])
    waitNeighbors(expected.entries[maxNeighbors:])
}

func TestUDP_findnodeMultiReply(t *testing.T) {
    test := newUDPTest(t)
    defer test.table.Close()

    // queue a pending findnode request
    resultc, errc := make(chan []*Node), make(chan error)
    go func() {
        rid := PubkeyID(&test.remotekey.PublicKey)
        ns, err := test.udp.findnode(rid, test.remoteaddr, testTarget)
        if err != nil && len(ns) == 0 {
            errc <- err
        } else {
            resultc <- ns
        }
    }()

    // wait for the findnode to be sent.
    // after it is sent, the transport is waiting for a reply
    test.waitPacketOut(func(p *findnode) {
        if p.Target != testTarget {
            t.Errorf("wrong target: got %v, want %v", p.Target, testTarget)
        }
    })

    // send the reply as two packets.
    list := []*Node{
        MustParseNode("enode://ba85011c70bcc5c04d8607d3a0ed29aa6179c092cbdda10d5d32684fb33ed01bd94f588ca8f91ac48318087dcb02eaf36773a7a453f0eedd6742af668097b29c@10.0.1.16:30303?discport=30304"),
        MustParseNode("enode://81fa361d25f157cd421c60dcc28d8dac5ef6a89476633339c5df30287474520caca09627da18543d9079b5b288698b542d56167aa5c09111e55acdbbdf2ef799@10.0.1.16:30303"),
        MustParseNode("enode://9bffefd833d53fac8e652415f4973bee289e8b1a5c6c4cbe70abf817ce8a64cee11b823b66a987f51aaa9fba0d6a91b3e6bf0d5a5d1042de8e9eeea057b217f8@10.0.1.36:30301?discport=17"),
        MustParseNode("enode://1b5b4aa662d7cb44a7221bfba67302590b643028197a7d5214790f3bac7aaa4a3241be9e83c09cf1f6c69d007c634faae3dc1b1221793e8446c0b3a09de65960@10.0.1.16:30303"),
    }
    rpclist := make([]rpcNode, len(list))
    for i := range list {
        rpclist[i] = nodeToRPC(list[i])
    }
    test.packetIn(nil, neighborsPacket, &neighbors{Expiration: futureExp, Nodes: rpclist[:2]})
    test.packetIn(nil, neighborsPacket, &neighbors{Expiration: futureExp, Nodes: rpclist[2:]})

    // check that the sent neighbors are all returned by findnode
    select {
    case result := <-resultc:
        want := append(list[:2], list[3:]...)
        if !reflect.DeepEqual(result, want) {
            t.Errorf("neighbors mismatch:\n  got:  %v\n  want: %v", result, want)
        }
    case err := <-errc:
        t.Errorf("findnode error: %v", err)
    case <-time.After(5 * time.Second):
        t.Error("findnode did not return within 5 seconds")
    }
}

func TestUDP_successfulPing(t *testing.T) {
    test := newUDPTest(t)
    added := make(chan *Node, 1)
    test.table.nodeAddedHook = func(n *Node) { added <- n }
    defer test.table.Close()

    // The remote side sends a ping packet to initiate the exchange.
    go test.packetIn(nil, pingPacket, &ping{From: testRemote, To: testLocalAnnounced, Version: Version, Expiration: futureExp})

    // the ping is replied to.
    test.waitPacketOut(func(p *pong) {
        pinghash := test.sent[0][:macSize]
        if !bytes.Equal(p.ReplyTok, pinghash) {
            t.Errorf("got pong.ReplyTok %x, want %x", p.ReplyTok, pinghash)
        }
        wantTo := rpcEndpoint{
            // The mirrored UDP address is the UDP packet sender
            IP: test.remoteaddr.IP, UDP: uint16(test.remoteaddr.Port),
            // The mirrored TCP port is the one from the ping packet
            TCP: testRemote.TCP,
        }
        if !reflect.DeepEqual(p.To, wantTo) {
            t.Errorf("got pong.To %v, want %v", p.To, wantTo)
        }
    })

    // remote is unknown, the table pings back.
    test.waitPacketOut(func(p *ping) error {
        if !reflect.DeepEqual(p.From, test.udp.ourEndpoint) {
            t.Errorf("got ping.From %v, want %v", p.From, test.udp.ourEndpoint)
        }
        wantTo := rpcEndpoint{
            // The mirrored UDP address is the UDP packet sender.
            IP: test.remoteaddr.IP, UDP: uint16(test.remoteaddr.Port),
            TCP: 0,
        }
        if !reflect.DeepEqual(p.To, wantTo) {
            t.Errorf("got ping.To %v, want %v", p.To, wantTo)
        }
        return nil
    })
    test.packetIn(nil, pongPacket, &pong{Expiration: futureExp})

    // the node should be added to the table shortly after getting the
    // pong packet.
    select {
    case n := <-added:
        rid := PubkeyID(&test.remotekey.PublicKey)
        if n.ID != rid {
            t.Errorf("node has wrong ID: got %v, want %v", n.ID, rid)
        }
        if !n.IP.Equal(test.remoteaddr.IP) {
            t.Errorf("node has wrong IP: got %v, want: %v", n.IP, test.remoteaddr.IP)
        }
        if int(n.UDP) != test.remoteaddr.Port {
            t.Errorf("node has wrong UDP port: got %v, want: %v", n.UDP, test.remoteaddr.Port)
        }
        if n.TCP != testRemote.TCP {
            t.Errorf("node has wrong TCP port: got %v, want: %v", n.TCP, testRemote.TCP)
        }
    case <-time.After(2 * time.Second):
        t.Errorf("node was not added within 2 seconds")
    }
}

var testPackets = []struct {
    input      string
    wantPacket interface{}
}{
    {
        input: "71dbda3a79554728d4f94411e42ee1f8b0d561c10e1e5f5893367948c6a7d70bb87b235fa28a77070271b6c164a2dce8c7e13a5739b53b5e96f2e5acb0e458a02902f5965d55ecbeb2ebb6cabb8b2b232896a36b737666c55265ad0a68412f250001ea04cb847f000001820cfa8215a8d790000000000000000000000000000000018208ae820d058443b9a355",
        wantPacket: &ping{
            Version:    4,
            From:       rpcEndpoint{net.ParseIP("127.0.0.1").To4(), 3322, 5544},
            To:         rpcEndpoint{net.ParseIP("::1"), 2222, 3333},
            Expiration: 1136239445,
            Rest:       []rlp.RawValue{},
        },
    },
    {
        input: "e9614ccfd9fc3e74360018522d30e1419a143407ffcce748de3e22116b7e8dc92ff74788c0b6663aaa3d67d641936511c8f8d6ad8698b820a7cf9e1be7155e9a241f556658c55428ec0563514365799a4be2be5a685a80971ddcfa80cb422cdd0101ec04cb847f000001820cfa8215a8d790000000000000000000000000000000018208ae820d058443b9a3550102",
        wantPacket: &ping{
            Version:    4,
            From:       rpcEndpoint{net.ParseIP("127.0.0.1").To4(), 3322, 5544},
            To:         rpcEndpoint{net.ParseIP("::1"), 2222, 3333},
            Expiration: 1136239445,
            Rest:       []rlp.RawValue{{0x01}, {0x02}},
        },
    },
    {
        input: "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",
        wantPacket: &ping{
            Version:    555,
            From:       rpcEndpoint{net.ParseIP("2001:db8:3c4d:15::abcd:ef12"), 3322, 5544},
            To:         rpcEndpoint{net.ParseIP("2001:db8:85a3:8d3:1319:8a2e:370:7348"), 2222, 33338},
            Expiration: 1136239445,
            Rest:       []rlp.RawValue{{0xC5, 0x01, 0x02, 0x03, 0x04, 0x05}},
        },
    },
    {
        input: "09b2428d83348d27cdf7064ad9024f526cebc19e4958f0fdad87c15eb598dd61d08423e0bf66b2069869e1724125f820d851c136684082774f870e614d95a2855d000f05d1648b2d5945470bc187c2d2216fbe870f43ed0909009882e176a46b0102f846d79020010db885a308d313198a2e037073488208ae82823aa0fbc914b16819237dcd8801d7e53f69e9719adecb3cc0e790c57e91ca4461c9548443b9a355c6010203c2040506a0c969a58f6f9095004c0177a6b47f451530cab38966a25cca5cb58f055542124e",
        wantPacket: &pong{
            To:         rpcEndpoint{net.ParseIP("2001:db8:85a3:8d3:1319:8a2e:370:7348"), 2222, 33338},
            ReplyTok:   common.Hex2Bytes("fbc914b16819237dcd8801d7e53f69e9719adecb3cc0e790c57e91ca4461c954"),
            Expiration: 1136239445,
            Rest:       []rlp.RawValue{{0xC6, 0x01, 0x02, 0x03, 0xC2, 0x04, 0x05}, {0x06}},
        },
    },
    {
        input: "c7c44041b9f7c7e41934417ebac9a8e1a4c6298f74553f2fcfdcae6ed6fe53163eb3d2b52e39fe91831b8a927bf4fc222c3902202027e5e9eb812195f95d20061ef5cd31d502e47ecb61183f74a504fe04c51e73df81f25c4d506b26db4517490103f84eb840ca634cae0d49acb401d8a4c6b6fe8c55b70d115bf400769cc1400f3258cd31387574077f301b421bc84df7266c44e9e6d569fc56be00812904767bf5ccd1fc7f8443b9a35582999983999999280dc62cc8255c73471e0a61da0c89acdc0e035e260add7fc0c04ad9ebf3919644c91cb247affc82b69bd2ca235c71eab8e49737c937a2c396",
        wantPacket: &findnode{
            Target:     MustHexID("ca634cae0d49acb401d8a4c6b6fe8c55b70d115bf400769cc1400f3258cd31387574077f301b421bc84df7266c44e9e6d569fc56be00812904767bf5ccd1fc7f"),
            Expiration: 1136239445,
            Rest:       []rlp.RawValue{{0x82, 0x99, 0x99}, {0x83, 0x99, 0x99, 0x99}},
        },
    },
    {
        input: "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",
        wantPacket: &neighbors{
            Nodes: []rpcNode{
                {
                    ID:  MustHexID("3155e1427f85f10a5c9a7755877748041af1bcd8d474ec065eb33df57a97babf54bfd2103575fa829115d224c523596b401065a97f74010610fce76382c0bf32"),
                    IP:  net.ParseIP("99.33.22.55").To4(),
                    UDP: 4444,
                    TCP: 4445,
                },
                {
                    ID:  MustHexID("312c55512422cf9b8a4097e9a6ad79402e87a15ae909a4bfefa22398f03d20951933beea1e4dfa6f968212385e829f04c2d314fc2d4e255e0d3bc08792b069db"),
                    IP:  net.ParseIP("1.2.3.4").To4(),
                    UDP: 1,
                    TCP: 1,
                },
                {
                    ID:  MustHexID("38643200b172dcfef857492156971f0e6aa2c538d8b74010f8e140811d53b98c765dd2d96126051913f44582e8c199ad7c6d6819e9a56483f637feaac9448aac"),
                    IP:  net.ParseIP("2001:db8:3c4d:15::abcd:ef12"),
                    UDP: 3333,
                    TCP: 3333,
                },
                {
                    ID:  MustHexID("8dcab8618c3253b558d459da53bd8fa68935a719aff8b811197101a4b2b47dd2d47295286fc00cc081bb542d760717d1bdd6bec2c37cd72eca367d6dd3b9df73"),
                    IP:  net.ParseIP("2001:db8:85a3:8d3:1319:8a2e:370:7348"),
                    UDP: 999,
                    TCP: 1000,
                },
            },
            Expiration: 1136239445,
            Rest:       []rlp.RawValue{{0x01}, {0x02}, {0x03}},
        },
    },
}

func TestForwardCompatibility(t *testing.T) {
    testkey, _ := crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
    wantNodeID := PubkeyID(&testkey.PublicKey)

    for _, test := range testPackets {
        input, err := hex.DecodeString(test.input)
        if err != nil {
            t.Fatalf("invalid hex: %s", test.input)
        }
        packet, nodeid, _, err := decodePacket(input)
        if err != nil {
            t.Errorf("did not accept packet %s\n%v", test.input, err)
            continue
        }
        if !reflect.DeepEqual(packet, test.wantPacket) {
            t.Errorf("got %s\nwant %s", spew.Sdump(packet), spew.Sdump(test.wantPacket))
        }
        if nodeid != wantNodeID {
            t.Errorf("got id %v\nwant id %v", nodeid, wantNodeID)
        }
    }
}

// dgramPipe is a fake UDP socket. It queues all sent datagrams.
type dgramPipe struct {
    mu      *sync.Mutex
    cond    *sync.Cond
    closing chan struct{}
    closed  bool
    queue   [][]byte
}

func newpipe() *dgramPipe {
    mu := new(sync.Mutex)
    return &dgramPipe{
        closing: make(chan struct{}),
        cond:    &sync.Cond{L: mu},
        mu:      mu,
    }
}

// WriteToUDP queues a datagram.
func (c *dgramPipe) WriteToUDP(b []byte, to *net.UDPAddr) (n int, err error) {
    msg := make([]byte, len(b))
    copy(msg, b)
    c.mu.Lock()
    defer c.mu.Unlock()
    if c.closed {
        return 0, errors.New("closed")
    }
    c.queue = append(c.queue, msg)
    c.cond.Signal()
    return len(b), nil
}

// ReadFromUDP just hangs until the pipe is closed.
func (c *dgramPipe) ReadFromUDP(b []byte) (n int, addr *net.UDPAddr, err error) {
    <-c.closing
    return 0, nil, io.EOF
}

func (c *dgramPipe) Close() error {
    c.mu.Lock()
    defer c.mu.Unlock()
    if !c.closed {
        close(c.closing)
        c.closed = true
    }
    return nil
}

func (c *dgramPipe) LocalAddr() net.Addr {
    return &net.UDPAddr{IP: testLocal.IP, Port: int(testLocal.UDP)}
}

func (c *dgramPipe) waitPacketOut() []byte {
    c.mu.Lock()
    defer c.mu.Unlock()
    for len(c.queue) == 0 {
        c.cond.Wait()
    }
    p := c.queue[0]
    copy(c.queue, c.queue[1:])
    c.queue = c.queue[:len(c.queue)-1]
    return p
}