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lightningnetwork / lnd / 13586005509

28 Feb 2025 10:14AM UTC coverage: 68.629% (+9.9%) from 58.77%
13586005509

Pull #9521

github

web-flow
Merge 37d3a70a5 into 8532955b3
Pull Request #9521: unit: remove GOACC, use Go 1.20 native coverage functionality

129950 of 189351 relevant lines covered (68.63%)

23726.46 hits per line

Source File
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71.02
/zpay32/encode.go
1
package zpay32
2

3
import (
4
        "bytes"
5
        "encoding/binary"
6
        "fmt"
7

8
        "github.com/btcsuite/btcd/btcutil"
9
        "github.com/btcsuite/btcd/btcutil/bech32"
10
        "github.com/btcsuite/btcd/chaincfg"
11
        "github.com/btcsuite/btcd/chaincfg/chainhash"
12
        "github.com/lightningnetwork/lnd/fn/v2"
13
        "github.com/lightningnetwork/lnd/lnwire"
14
)
15

16
// Encode takes the given MessageSigner and returns a string encoding this
17
// invoice signed by the node key of the signer.
18
func (invoice *Invoice) Encode(signer MessageSigner) (string, error) {
220✔
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        // First check that this invoice is valid before starting the encoding.
220✔
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        if err := validateInvoice(invoice); err != nil {
223✔
21
                return "", err
3✔
22
        }
3✔
23

24
        // The buffer will encoded the invoice data using 5-bit groups (base32).
25
        var bufferBase32 bytes.Buffer
217✔
26

217✔
27
        // The timestamp will be encoded using 35 bits, in base32.
217✔
28
        timestampBase32 := uint64ToBase32(uint64(invoice.Timestamp.Unix()))
217✔
29

217✔
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        // The timestamp must be exactly 35 bits, which means 7 groups. If it
217✔
31
        // can fit into fewer groups we add leading zero groups, if it is too
217✔
32
        // big we fail early, as there is not possible to encode it.
217✔
33
        if len(timestampBase32) > timestampBase32Len {
217✔
34
                return "", fmt.Errorf("timestamp too big: %d",
×
35
                        invoice.Timestamp.Unix())
×
36
        }
×
37

38
        // Add zero bytes to the first timestampBase32Len-len(timestampBase32)
39
        // groups, then add the non-zero groups.
40
        zeroes := make([]byte, timestampBase32Len-len(timestampBase32))
217✔
41
        _, err := bufferBase32.Write(zeroes)
217✔
42
        if err != nil {
217✔
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                return "", fmt.Errorf("unable to write to buffer: %w", err)
×
44
        }
×
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        _, err = bufferBase32.Write(timestampBase32)
217✔
46
        if err != nil {
217✔
47
                return "", fmt.Errorf("unable to write to buffer: %w", err)
×
48
        }
×
49

50
        // We now write the tagged fields to the buffer, which will fill the
51
        // rest of the data part before the signature.
52
        if err := writeTaggedFields(&bufferBase32, invoice); err != nil {
217✔
53
                return "", err
×
54
        }
×
55

56
        // The human-readable part (hrp) is "ln" + net hrp + optional amount,
57
        // except for signet where we add an additional "s" to differentiate it
58
        // from the older testnet3 (Core devs decided to use the same hrp for
59
        // signet as for testnet3 which is not optimal for LN). See
60
        // https://github.com/lightningnetwork/lightning-rfc/pull/844 for more
61
        // information.
62
        hrp := "ln" + invoice.Net.Bech32HRPSegwit
217✔
63
        if invoice.Net.Name == chaincfg.SigNetParams.Name {
234✔
64
                hrp = "lntbs"
17✔
65
        }
17✔
66
        if invoice.MilliSat != nil {
362✔
67
                // Encode the amount using the fewest possible characters.
145✔
68
                am, err := encodeAmount(*invoice.MilliSat)
145✔
69
                if err != nil {
145✔
70
                        return "", err
×
71
                }
×
72
                hrp += am
145✔
73
        }
74

75
        // The signature is over the single SHA-256 hash of the hrp + the
76
        // tagged fields encoded in base256.
77
        taggedFieldsBytes, err := bech32.ConvertBits(bufferBase32.Bytes(), 5, 8, true)
217✔
78
        if err != nil {
217✔
79
                return "", err
×
80
        }
×
81

82
        toSign := append([]byte(hrp), taggedFieldsBytes...)
217✔
83

217✔
84
        // We use compact signature format, and also encoded the recovery ID
217✔
85
        // such that a reader of the invoice can recover our pubkey from the
217✔
86
        // signature.
217✔
87
        sign, err := signer.SignCompact(toSign)
217✔
88
        if err != nil {
217✔
89
                return "", err
×
90
        }
×
91

92
        // From the header byte we can extract the recovery ID, and the last 64
93
        // bytes encode the signature.
94
        recoveryID := sign[0] - 27 - 4
217✔
95
        sig, err := lnwire.NewSigFromWireECDSA(sign[1:])
217✔
96
        if err != nil {
217✔
97
                return "", err
×
98
        }
×
99

100
        // If the pubkey field was explicitly set, it must be set to the pubkey
101
        // used to create the signature.
102
        if invoice.Destination != nil {
320✔
103
                signature, err := sig.ToSignature()
103✔
104
                if err != nil {
103✔
105
                        return "", fmt.Errorf("unable to deserialize "+
×
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                                "signature: %v", err)
×
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                }
×
108

109
                hash := chainhash.HashB(toSign)
103✔
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                valid := signature.Verify(hash, invoice.Destination)
103✔
111
                if !valid {
195✔
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                        return "", fmt.Errorf("signature does not match " +
92✔
113
                                "provided pubkey")
92✔
114
                }
92✔
115
        }
116

117
        // Convert the signature to base32 before writing it to the buffer.
118
        signBase32, err := bech32.ConvertBits(
125✔
119
                append(sig.RawBytes(), recoveryID),
125✔
120
                8, 5, true,
125✔
121
        )
125✔
122
        if err != nil {
125✔
123
                return "", err
×
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        }
×
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        bufferBase32.Write(signBase32)
125✔
126

125✔
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        // Now we can create the bech32 encoded string from the base32 buffer.
125✔
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        b32, err := bech32.Encode(hrp, bufferBase32.Bytes())
125✔
129
        if err != nil {
125✔
130
                return "", err
×
131
        }
×
132

133
        // Before returning, check that the bech32 encoded string is not greater
134
        // than our largest supported invoice size.
135
        if len(b32) > maxInvoiceLength {
125✔
136
                return "", ErrInvoiceTooLarge
×
137
        }
×
138

139
        return b32, nil
125✔
140
}
141

142
// writeTaggedFields writes the non-nil tagged fields of the Invoice to the
143
// base32 buffer.
144
func writeTaggedFields(bufferBase32 *bytes.Buffer, invoice *Invoice) error {
217✔
145
        if invoice.PaymentHash != nil {
434✔
146
                err := writeBytes32(bufferBase32, fieldTypeP, *invoice.PaymentHash)
217✔
147
                if err != nil {
217✔
148
                        return err
×
149
                }
×
150
        }
151

152
        if invoice.Description != nil {
410✔
153
                base32, err := bech32.ConvertBits([]byte(*invoice.Description),
193✔
154
                        8, 5, true)
193✔
155
                if err != nil {
193✔
156
                        return err
×
157
                }
×
158
                err = writeTaggedField(bufferBase32, fieldTypeD, base32)
193✔
159
                if err != nil {
193✔
160
                        return err
×
161
                }
×
162
        }
163

164
        if invoice.DescriptionHash != nil {
241✔
165
                err := writeBytes32(
24✔
166
                        bufferBase32, fieldTypeH, *invoice.DescriptionHash,
24✔
167
                )
24✔
168
                if err != nil {
24✔
169
                        return err
×
170
                }
×
171
        }
172

173
        if invoice.Metadata != nil {
225✔
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                base32, err := bech32.ConvertBits(invoice.Metadata, 8, 5, true)
8✔
175
                if err != nil {
8✔
176
                        return err
×
177
                }
×
178
                err = writeTaggedField(bufferBase32, fieldTypeM, base32)
8✔
179
                if err != nil {
8✔
180
                        return err
×
181
                }
×
182
        }
183

184
        if invoice.minFinalCLTVExpiry != nil {
231✔
185
                finalDelta := uint64ToBase32(*invoice.minFinalCLTVExpiry)
14✔
186
                err := writeTaggedField(bufferBase32, fieldTypeC, finalDelta)
14✔
187
                if err != nil {
14✔
188
                        return err
×
189
                }
×
190
        }
191

192
        if invoice.expiry != nil {
322✔
193
                seconds := invoice.expiry.Seconds()
105✔
194
                expiry := uint64ToBase32(uint64(seconds))
105✔
195
                err := writeTaggedField(bufferBase32, fieldTypeX, expiry)
105✔
196
                if err != nil {
105✔
197
                        return err
×
198
                }
×
199
        }
200

201
        if invoice.FallbackAddr != nil {
228✔
202
                var version byte
11✔
203
                switch addr := invoice.FallbackAddr.(type) {
11✔
204
                case *btcutil.AddressPubKeyHash:
6✔
205
                        version = 17
6✔
206
                case *btcutil.AddressScriptHash:
2✔
207
                        version = 18
2✔
208
                case *btcutil.AddressWitnessPubKeyHash:
2✔
209
                        version = addr.WitnessVersion()
2✔
210
                case *btcutil.AddressWitnessScriptHash:
1✔
211
                        version = addr.WitnessVersion()
1✔
212
                default:
×
213
                        return fmt.Errorf("unknown fallback address type")
×
214
                }
215
                base32Addr, err := bech32.ConvertBits(
11✔
216
                        invoice.FallbackAddr.ScriptAddress(), 8, 5, true)
11✔
217
                if err != nil {
11✔
218
                        return err
×
219
                }
×
220

221
                err = writeTaggedField(bufferBase32, fieldTypeF,
11✔
222
                        append([]byte{version}, base32Addr...))
11✔
223
                if err != nil {
11✔
224
                        return err
×
225
                }
×
226
        }
227

228
        for _, routeHint := range invoice.RouteHints {
227✔
229
                // Each hop hint is encoded using 51 bytes, so we'll make to
10✔
230
                // sure to allocate enough space for the whole route hint.
10✔
231
                routeHintBase256 := make([]byte, 0, hopHintLen*len(routeHint))
10✔
232

10✔
233
                for _, hopHint := range routeHint {
24✔
234
                        hopHintBase256 := make([]byte, hopHintLen)
14✔
235
                        copy(hopHintBase256[:33], hopHint.NodeID.SerializeCompressed())
14✔
236
                        binary.BigEndian.PutUint64(
14✔
237
                                hopHintBase256[33:41], hopHint.ChannelID,
14✔
238
                        )
14✔
239
                        binary.BigEndian.PutUint32(
14✔
240
                                hopHintBase256[41:45], hopHint.FeeBaseMSat,
14✔
241
                        )
14✔
242
                        binary.BigEndian.PutUint32(
14✔
243
                                hopHintBase256[45:49], hopHint.FeeProportionalMillionths,
14✔
244
                        )
14✔
245
                        binary.BigEndian.PutUint16(
14✔
246
                                hopHintBase256[49:51], hopHint.CLTVExpiryDelta,
14✔
247
                        )
14✔
248
                        routeHintBase256 = append(routeHintBase256, hopHintBase256...)
14✔
249
                }
14✔
250

251
                routeHintBase32, err := bech32.ConvertBits(
10✔
252
                        routeHintBase256, 8, 5, true,
10✔
253
                )
10✔
254
                if err != nil {
10✔
255
                        return err
×
256
                }
×
257

258
                err = writeTaggedField(bufferBase32, fieldTypeR, routeHintBase32)
10✔
259
                if err != nil {
10✔
260
                        return err
×
261
                }
×
262
        }
263

264
        for _, path := range invoice.BlindedPaymentPaths {
224✔
265
                var buf bytes.Buffer
7✔
266

7✔
267
                err := path.Encode(&buf)
7✔
268
                if err != nil {
7✔
269
                        return err
×
270
                }
×
271

272
                blindedPathBase32, err := bech32.ConvertBits(
7✔
273
                        buf.Bytes(), 8, 5, true,
7✔
274
                )
7✔
275
                if err != nil {
7✔
276
                        return err
×
277
                }
×
278

279
                err = writeTaggedField(
7✔
280
                        bufferBase32, fieldTypeB, blindedPathBase32,
7✔
281
                )
7✔
282
                if err != nil {
7✔
283
                        return err
×
284
                }
×
285
        }
286

287
        if invoice.Destination != nil {
320✔
288
                // Convert 33 byte pubkey to 53 5-bit groups.
103✔
289
                pubKeyBase32, err := bech32.ConvertBits(
103✔
290
                        invoice.Destination.SerializeCompressed(), 8, 5, true)
103✔
291
                if err != nil {
103✔
292
                        return err
×
293
                }
×
294

295
                if len(pubKeyBase32) != pubKeyBase32Len {
103✔
296
                        return fmt.Errorf("invalid pubkey length: %d",
×
297
                                len(invoice.Destination.SerializeCompressed()))
×
298
                }
×
299

300
                err = writeTaggedField(bufferBase32, fieldTypeN, pubKeyBase32)
103✔
301
                if err != nil {
103✔
302
                        return err
×
303
                }
×
304
        }
305

306
        err := fn.MapOptionZ(invoice.PaymentAddr, func(addr [32]byte) error {
320✔
307
                return writeBytes32(bufferBase32, fieldTypeS, addr)
103✔
308
        })
103✔
309
        if err != nil {
217✔
310
                return err
×
311
        }
×
312

313
        if invoice.Features.SerializeSize32() > 0 {
256✔
314
                var b bytes.Buffer
39✔
315
                err := invoice.Features.RawFeatureVector.EncodeBase32(&b)
39✔
316
                if err != nil {
39✔
317
                        return err
×
318
                }
×
319

320
                err = writeTaggedField(bufferBase32, fieldType9, b.Bytes())
39✔
321
                if err != nil {
39✔
322
                        return err
×
323
                }
×
324
        }
325

326
        return nil
217✔
327
}
328

329
// writeBytes32 encodes a 32-byte array as base32 and writes it to bufferBase32
330
// under the passed fieldType.
331
func writeBytes32(bufferBase32 *bytes.Buffer, fieldType byte, b [32]byte) error {
341✔
332
        // Convert 32 byte hash to 52 5-bit groups.
341✔
333
        base32, err := bech32.ConvertBits(b[:], 8, 5, true)
341✔
334
        if err != nil {
341✔
335
                return err
×
336
        }
×
337

338
        return writeTaggedField(bufferBase32, fieldType, base32)
341✔
339
}
340

341
// writeTaggedField takes the type of a tagged data field, and the data of
342
// the tagged field (encoded in base32), and writes the type, length and data
343
// to the buffer.
344
func writeTaggedField(bufferBase32 *bytes.Buffer, dataType byte, data []byte) error {
813✔
345
        // Length must be exactly 10 bits, so add leading zero groups if
813✔
346
        // needed.
813✔
347
        lenBase32 := uint64ToBase32(uint64(len(data)))
813✔
348
        for len(lenBase32) < 2 {
1,129✔
349
                lenBase32 = append([]byte{0}, lenBase32...)
316✔
350
        }
316✔
351

352
        if len(lenBase32) != 2 {
813✔
353
                return fmt.Errorf("data length too big to fit within 10 bits: %d",
×
354
                        len(data))
×
355
        }
×
356

357
        err := bufferBase32.WriteByte(dataType)
813✔
358
        if err != nil {
813✔
359
                return fmt.Errorf("unable to write to buffer: %w", err)
×
360
        }
×
361
        _, err = bufferBase32.Write(lenBase32)
813✔
362
        if err != nil {
813✔
363
                return fmt.Errorf("unable to write to buffer: %w", err)
×
364
        }
×
365
        _, err = bufferBase32.Write(data)
813✔
366
        if err != nil {
813✔
367
                return fmt.Errorf("unable to write to buffer: %w", err)
×
368
        }
×
369

370
        return nil
813✔
371
}
372

373
// uint64ToBase32 converts a uint64 to a base32 encoded integer encoded using
374
// as few 5-bit groups as possible.
375
func uint64ToBase32(num uint64) []byte {
1,141✔
376
        // Return at least one group.
1,141✔
377
        if num == 0 {
1,184✔
378
                return []byte{0}
43✔
379
        }
43✔
380

381
        // To fit an uint64, we need at most is ceil(64 / 5) = 13 groups.
382
        arr := make([]byte, 13)
1,101✔
383
        i := 13
1,101✔
384
        for num > 0 {
4,194✔
385
                i--
3,093✔
386
                arr[i] = byte(num & uint64(31)) // 0b11111 in binary
3,093✔
387
                num >>= 5
3,093✔
388
        }
3,093✔
389

390
        // We only return non-zero leading groups.
391
        return arr[i:]
1,101✔
392
}
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