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Merge pull request #2226 from alecchendev/2023-04-persist-network-graph-on-rgs
[rust-lightning] / lightning / src / offers / refund.rs
1 // This file is Copyright its original authors, visible in version control
2 // history.
3 //
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
8 // licenses.
9
10 //! Data structures and encoding for refunds.
11 //!
12 //! A [`Refund`] is an "offer for money" and is typically constructed by a merchant and presented
13 //! directly to the customer. The recipient responds with an [`Invoice`] to be paid.
14 //!
15 //! This is an [`InvoiceRequest`] produced *not* in response to an [`Offer`].
16 //!
17 //! [`Invoice`]: crate::offers::invoice::Invoice
18 //! [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
19 //! [`Offer`]: crate::offers::offer::Offer
20 //!
21 //! ```
22 //! extern crate bitcoin;
23 //! extern crate core;
24 //! extern crate lightning;
25 //!
26 //! use core::convert::TryFrom;
27 //! use core::time::Duration;
28 //!
29 //! use bitcoin::network::constants::Network;
30 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
31 //! use lightning::offers::parse::ParseError;
32 //! use lightning::offers::refund::{Refund, RefundBuilder};
33 //! use lightning::util::ser::{Readable, Writeable};
34 //!
35 //! # use lightning::blinded_path::BlindedPath;
36 //! # #[cfg(feature = "std")]
37 //! # use std::time::SystemTime;
38 //! #
39 //! # fn create_blinded_path() -> BlindedPath { unimplemented!() }
40 //! # fn create_another_blinded_path() -> BlindedPath { unimplemented!() }
41 //! #
42 //! # #[cfg(feature = "std")]
43 //! # fn build() -> Result<(), ParseError> {
44 //! let secp_ctx = Secp256k1::new();
45 //! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
46 //! let pubkey = PublicKey::from(keys);
47 //!
48 //! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
49 //! let refund = RefundBuilder::new("coffee, large".to_string(), vec![1; 32], pubkey, 20_000)?
50 //!     .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
51 //!     .issuer("Foo Bar".to_string())
52 //!     .path(create_blinded_path())
53 //!     .path(create_another_blinded_path())
54 //!     .chain(Network::Bitcoin)
55 //!     .payer_note("refund for order #12345".to_string())
56 //!     .build()?;
57 //!
58 //! // Encode as a bech32 string for use in a QR code.
59 //! let encoded_refund = refund.to_string();
60 //!
61 //! // Parse from a bech32 string after scanning from a QR code.
62 //! let refund = encoded_refund.parse::<Refund>()?;
63 //!
64 //! // Encode refund as raw bytes.
65 //! let mut bytes = Vec::new();
66 //! refund.write(&mut bytes).unwrap();
67 //!
68 //! // Decode raw bytes into an refund.
69 //! let refund = Refund::try_from(bytes)?;
70 //! # Ok(())
71 //! # }
72 //! ```
73
74 use bitcoin::blockdata::constants::ChainHash;
75 use bitcoin::network::constants::Network;
76 use bitcoin::secp256k1::{PublicKey, Secp256k1, self};
77 use core::convert::TryFrom;
78 use core::ops::Deref;
79 use core::str::FromStr;
80 use core::time::Duration;
81 use crate::sign::EntropySource;
82 use crate::io;
83 use crate::blinded_path::BlindedPath;
84 use crate::ln::PaymentHash;
85 use crate::ln::features::InvoiceRequestFeatures;
86 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
87 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
88 use crate::offers::invoice::{BlindedPayInfo, DerivedSigningPubkey, ExplicitSigningPubkey, InvoiceBuilder};
89 use crate::offers::invoice_request::{InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef};
90 use crate::offers::offer::{OfferTlvStream, OfferTlvStreamRef};
91 use crate::offers::parse::{Bech32Encode, ParseError, ParsedMessage, SemanticError};
92 use crate::offers::payer::{PayerContents, PayerTlvStream, PayerTlvStreamRef};
93 use crate::offers::signer::{Metadata, MetadataMaterial, self};
94 use crate::util::ser::{SeekReadable, WithoutLength, Writeable, Writer};
95 use crate::util::string::PrintableString;
96
97 use crate::prelude::*;
98
99 #[cfg(feature = "std")]
100 use std::time::SystemTime;
101
102 pub(super) const IV_BYTES: &[u8; IV_LEN] = b"LDK Refund ~~~~~";
103
104 /// Builds a [`Refund`] for the "offer for money" flow.
105 ///
106 /// See [module-level documentation] for usage.
107 ///
108 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
109 ///
110 /// [module-level documentation]: self
111 pub struct RefundBuilder<'a, T: secp256k1::Signing> {
112         refund: RefundContents,
113         secp_ctx: Option<&'a Secp256k1<T>>,
114 }
115
116 impl<'a> RefundBuilder<'a, secp256k1::SignOnly> {
117         /// Creates a new builder for a refund using the [`Refund::payer_id`] for the public node id to
118         /// send to if no [`Refund::paths`] are set. Otherwise, it may be a transient pubkey.
119         ///
120         /// Additionally, sets the required [`Refund::description`], [`Refund::metadata`], and
121         /// [`Refund::amount_msats`].
122         pub fn new(
123                 description: String, metadata: Vec<u8>, payer_id: PublicKey, amount_msats: u64
124         ) -> Result<Self, SemanticError> {
125                 if amount_msats > MAX_VALUE_MSAT {
126                         return Err(SemanticError::InvalidAmount);
127                 }
128
129                 let metadata = Metadata::Bytes(metadata);
130                 Ok(Self {
131                         refund: RefundContents {
132                                 payer: PayerContents(metadata), description, absolute_expiry: None, issuer: None,
133                                 paths: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
134                                 quantity: None, payer_id, payer_note: None,
135                         },
136                         secp_ctx: None,
137                 })
138         }
139 }
140
141 impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
142         /// Similar to [`RefundBuilder::new`] except, if [`RefundBuilder::path`] is called, the payer id
143         /// is derived from the given [`ExpandedKey`] and nonce. This provides sender privacy by using a
144         /// different payer id for each refund, assuming a different nonce is used.  Otherwise, the
145         /// provided `node_id` is used for the payer id.
146         ///
147         /// Also, sets the metadata when [`RefundBuilder::build`] is called such that it can be used to
148         /// verify that an [`InvoiceRequest`] was produced for the refund given an [`ExpandedKey`].
149         ///
150         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
151         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
152         pub fn deriving_payer_id<ES: Deref>(
153                 description: String, node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
154                 secp_ctx: &'a Secp256k1<T>, amount_msats: u64
155         ) -> Result<Self, SemanticError> where ES::Target: EntropySource {
156                 if amount_msats > MAX_VALUE_MSAT {
157                         return Err(SemanticError::InvalidAmount);
158                 }
159
160                 let nonce = Nonce::from_entropy_source(entropy_source);
161                 let derivation_material = MetadataMaterial::new(nonce, expanded_key, IV_BYTES);
162                 let metadata = Metadata::DerivedSigningPubkey(derivation_material);
163                 Ok(Self {
164                         refund: RefundContents {
165                                 payer: PayerContents(metadata), description, absolute_expiry: None, issuer: None,
166                                 paths: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
167                                 quantity: None, payer_id: node_id, payer_note: None,
168                         },
169                         secp_ctx: Some(secp_ctx),
170                 })
171         }
172
173         /// Sets the [`Refund::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
174         /// already passed is valid and can be checked for using [`Refund::is_expired`].
175         ///
176         /// Successive calls to this method will override the previous setting.
177         pub fn absolute_expiry(mut self, absolute_expiry: Duration) -> Self {
178                 self.refund.absolute_expiry = Some(absolute_expiry);
179                 self
180         }
181
182         /// Sets the [`Refund::issuer`].
183         ///
184         /// Successive calls to this method will override the previous setting.
185         pub fn issuer(mut self, issuer: String) -> Self {
186                 self.refund.issuer = Some(issuer);
187                 self
188         }
189
190         /// Adds a blinded path to [`Refund::paths`]. Must include at least one path if only connected
191         /// by private channels or if [`Refund::payer_id`] is not a public node id.
192         ///
193         /// Successive calls to this method will add another blinded path. Caller is responsible for not
194         /// adding duplicate paths.
195         pub fn path(mut self, path: BlindedPath) -> Self {
196                 self.refund.paths.get_or_insert_with(Vec::new).push(path);
197                 self
198         }
199
200         /// Sets the [`Refund::chain`] of the given [`Network`] for paying an invoice. If not
201         /// called, [`Network::Bitcoin`] is assumed.
202         ///
203         /// Successive calls to this method will override the previous setting.
204         pub fn chain(mut self, network: Network) -> Self {
205                 self.refund.chain = Some(ChainHash::using_genesis_block(network));
206                 self
207         }
208
209         /// Sets [`Refund::quantity`] of items. This is purely for informational purposes. It is useful
210         /// when the refund pertains to an [`Invoice`] that paid for more than one item from an
211         /// [`Offer`] as specified by [`InvoiceRequest::quantity`].
212         ///
213         /// Successive calls to this method will override the previous setting.
214         ///
215         /// [`Invoice`]: crate::offers::invoice::Invoice
216         /// [`InvoiceRequest::quantity`]: crate::offers::invoice_request::InvoiceRequest::quantity
217         /// [`Offer`]: crate::offers::offer::Offer
218         pub fn quantity(mut self, quantity: u64) -> Self {
219                 self.refund.quantity = Some(quantity);
220                 self
221         }
222
223         /// Sets the [`Refund::payer_note`].
224         ///
225         /// Successive calls to this method will override the previous setting.
226         pub fn payer_note(mut self, payer_note: String) -> Self {
227                 self.refund.payer_note = Some(payer_note);
228                 self
229         }
230
231         /// Builds a [`Refund`] after checking for valid semantics.
232         pub fn build(mut self) -> Result<Refund, SemanticError> {
233                 if self.refund.chain() == self.refund.implied_chain() {
234                         self.refund.chain = None;
235                 }
236
237                 // Create the metadata for stateless verification of an Invoice.
238                 if self.refund.payer.0.has_derivation_material() {
239                         let mut metadata = core::mem::take(&mut self.refund.payer.0);
240
241                         if self.refund.paths.is_none() {
242                                 metadata = metadata.without_keys();
243                         }
244
245                         let mut tlv_stream = self.refund.as_tlv_stream();
246                         tlv_stream.0.metadata = None;
247                         if metadata.derives_keys() {
248                                 tlv_stream.2.payer_id = None;
249                         }
250
251                         let (derived_metadata, keys) = metadata.derive_from(tlv_stream, self.secp_ctx);
252                         metadata = derived_metadata;
253                         if let Some(keys) = keys {
254                                 self.refund.payer_id = keys.public_key();
255                         }
256
257                         self.refund.payer.0 = metadata;
258                 }
259
260                 let mut bytes = Vec::new();
261                 self.refund.write(&mut bytes).unwrap();
262
263                 Ok(Refund { bytes, contents: self.refund })
264         }
265 }
266
267 #[cfg(test)]
268 impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
269         fn features_unchecked(mut self, features: InvoiceRequestFeatures) -> Self {
270                 self.refund.features = features;
271                 self
272         }
273 }
274
275 /// A `Refund` is a request to send an [`Invoice`] without a preceding [`Offer`].
276 ///
277 /// Typically, after an invoice is paid, the recipient may publish a refund allowing the sender to
278 /// recoup their funds. A refund may be used more generally as an "offer for money", such as with a
279 /// bitcoin ATM.
280 ///
281 /// [`Invoice`]: crate::offers::invoice::Invoice
282 /// [`Offer`]: crate::offers::offer::Offer
283 #[derive(Clone, Debug)]
284 #[cfg_attr(test, derive(PartialEq))]
285 pub struct Refund {
286         pub(super) bytes: Vec<u8>,
287         pub(super) contents: RefundContents,
288 }
289
290 /// The contents of a [`Refund`], which may be shared with an [`Invoice`].
291 ///
292 /// [`Invoice`]: crate::offers::invoice::Invoice
293 #[derive(Clone, Debug)]
294 #[cfg_attr(test, derive(PartialEq))]
295 pub(super) struct RefundContents {
296         payer: PayerContents,
297         // offer fields
298         description: String,
299         absolute_expiry: Option<Duration>,
300         issuer: Option<String>,
301         paths: Option<Vec<BlindedPath>>,
302         // invoice_request fields
303         chain: Option<ChainHash>,
304         amount_msats: u64,
305         features: InvoiceRequestFeatures,
306         quantity: Option<u64>,
307         payer_id: PublicKey,
308         payer_note: Option<String>,
309 }
310
311 impl Refund {
312         /// A complete description of the purpose of the refund. Intended to be displayed to the user
313         /// but with the caveat that it has not been verified in any way.
314         pub fn description(&self) -> PrintableString {
315                 self.contents.description()
316         }
317
318         /// Duration since the Unix epoch when an invoice should no longer be sent.
319         ///
320         /// If `None`, the refund does not expire.
321         pub fn absolute_expiry(&self) -> Option<Duration> {
322                 self.contents.absolute_expiry
323         }
324
325         /// Whether the refund has expired.
326         #[cfg(feature = "std")]
327         pub fn is_expired(&self) -> bool {
328                 self.contents.is_expired()
329         }
330
331         /// The issuer of the refund, possibly beginning with `user@domain` or `domain`. Intended to be
332         /// displayed to the user but with the caveat that it has not been verified in any way.
333         pub fn issuer(&self) -> Option<PrintableString> {
334                 self.contents.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
335         }
336
337         /// Paths to the sender originating from publicly reachable nodes. Blinded paths provide sender
338         /// privacy by obfuscating its node id.
339         pub fn paths(&self) -> &[BlindedPath] {
340                 self.contents.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
341         }
342
343         /// An unpredictable series of bytes, typically containing information about the derivation of
344         /// [`payer_id`].
345         ///
346         /// [`payer_id`]: Self::payer_id
347         pub fn metadata(&self) -> &[u8] {
348                 self.contents.metadata()
349         }
350
351         /// A chain that the refund is valid for.
352         pub fn chain(&self) -> ChainHash {
353                 self.contents.chain.unwrap_or_else(|| self.contents.implied_chain())
354         }
355
356         /// The amount to refund in msats (i.e., the minimum lightning-payable unit for [`chain`]).
357         ///
358         /// [`chain`]: Self::chain
359         pub fn amount_msats(&self) -> u64 {
360                 self.contents.amount_msats
361         }
362
363         /// Features pertaining to requesting an invoice.
364         pub fn features(&self) -> &InvoiceRequestFeatures {
365                 &self.contents.features
366         }
367
368         /// The quantity of an item that refund is for.
369         pub fn quantity(&self) -> Option<u64> {
370                 self.contents.quantity
371         }
372
373         /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
374         /// transient pubkey.
375         ///
376         /// [`paths`]: Self::paths
377         pub fn payer_id(&self) -> PublicKey {
378                 self.contents.payer_id
379         }
380
381         /// Payer provided note to include in the invoice.
382         pub fn payer_note(&self) -> Option<PrintableString> {
383                 self.contents.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
384         }
385
386         /// Creates an [`InvoiceBuilder`] for the refund with the given required fields and using the
387         /// [`Duration`] since [`std::time::SystemTime::UNIX_EPOCH`] as the creation time.
388         ///
389         /// See [`Refund::respond_with_no_std`] for further details where the aforementioned creation
390         /// time is used for the `created_at` parameter.
391         ///
392         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
393         ///
394         /// [`Duration`]: core::time::Duration
395         #[cfg(feature = "std")]
396         pub fn respond_with(
397                 &self, payment_paths: Vec<(BlindedPath, BlindedPayInfo)>, payment_hash: PaymentHash,
398                 signing_pubkey: PublicKey,
399         ) -> Result<InvoiceBuilder<ExplicitSigningPubkey>, SemanticError> {
400                 let created_at = std::time::SystemTime::now()
401                         .duration_since(std::time::SystemTime::UNIX_EPOCH)
402                         .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
403
404                 self.respond_with_no_std(payment_paths, payment_hash, signing_pubkey, created_at)
405         }
406
407         /// Creates an [`InvoiceBuilder`] for the refund with the given required fields.
408         ///
409         /// Unless [`InvoiceBuilder::relative_expiry`] is set, the invoice will expire two hours after
410         /// `created_at`, which is used to set [`Invoice::created_at`]. Useful for `no-std` builds where
411         /// [`std::time::SystemTime`] is not available.
412         ///
413         /// The caller is expected to remember the preimage of `payment_hash` in order to
414         /// claim a payment for the invoice.
415         ///
416         /// The `signing_pubkey` is required to sign the invoice since refunds are not in response to an
417         /// offer, which does have a `signing_pubkey`.
418         ///
419         /// The `payment_paths` parameter is useful for maintaining the payment recipient's privacy. It
420         /// must contain one or more elements ordered from most-preferred to least-preferred, if there's
421         /// a preference. Note, however, that any privacy is lost if a public node id is used for
422         /// `signing_pubkey`.
423         ///
424         /// Errors if the request contains unknown required features.
425         ///
426         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
427         ///
428         /// [`Invoice::created_at`]: crate::offers::invoice::Invoice::created_at
429         pub fn respond_with_no_std(
430                 &self, payment_paths: Vec<(BlindedPath, BlindedPayInfo)>, payment_hash: PaymentHash,
431                 signing_pubkey: PublicKey, created_at: Duration
432         ) -> Result<InvoiceBuilder<ExplicitSigningPubkey>, SemanticError> {
433                 if self.features().requires_unknown_bits() {
434                         return Err(SemanticError::UnknownRequiredFeatures);
435                 }
436
437                 InvoiceBuilder::for_refund(self, payment_paths, created_at, payment_hash, signing_pubkey)
438         }
439
440         /// Creates an [`InvoiceBuilder`] for the refund using the given required fields and that uses
441         /// derived signing keys to sign the [`Invoice`].
442         ///
443         /// See [`Refund::respond_with`] for further details.
444         ///
445         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
446         ///
447         /// [`Invoice`]: crate::offers::invoice::Invoice
448         #[cfg(feature = "std")]
449         pub fn respond_using_derived_keys<ES: Deref>(
450                 &self, payment_paths: Vec<(BlindedPath, BlindedPayInfo)>, payment_hash: PaymentHash,
451                 expanded_key: &ExpandedKey, entropy_source: ES
452         ) -> Result<InvoiceBuilder<DerivedSigningPubkey>, SemanticError>
453         where
454                 ES::Target: EntropySource,
455         {
456                 let created_at = std::time::SystemTime::now()
457                         .duration_since(std::time::SystemTime::UNIX_EPOCH)
458                         .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
459
460                 self.respond_using_derived_keys_no_std(
461                         payment_paths, payment_hash, created_at, expanded_key, entropy_source
462                 )
463         }
464
465         /// Creates an [`InvoiceBuilder`] for the refund using the given required fields and that uses
466         /// derived signing keys to sign the [`Invoice`].
467         ///
468         /// See [`Refund::respond_with_no_std`] for further details.
469         ///
470         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
471         ///
472         /// [`Invoice`]: crate::offers::invoice::Invoice
473         pub fn respond_using_derived_keys_no_std<ES: Deref>(
474                 &self, payment_paths: Vec<(BlindedPath, BlindedPayInfo)>, payment_hash: PaymentHash,
475                 created_at: core::time::Duration, expanded_key: &ExpandedKey, entropy_source: ES
476         ) -> Result<InvoiceBuilder<DerivedSigningPubkey>, SemanticError>
477         where
478                 ES::Target: EntropySource,
479         {
480                 if self.features().requires_unknown_bits() {
481                         return Err(SemanticError::UnknownRequiredFeatures);
482                 }
483
484                 let nonce = Nonce::from_entropy_source(entropy_source);
485                 let keys = signer::derive_keys(nonce, expanded_key);
486                 InvoiceBuilder::for_refund_using_keys(self, payment_paths, created_at, payment_hash, keys)
487         }
488
489         #[cfg(test)]
490         fn as_tlv_stream(&self) -> RefundTlvStreamRef {
491                 self.contents.as_tlv_stream()
492         }
493 }
494
495 impl AsRef<[u8]> for Refund {
496         fn as_ref(&self) -> &[u8] {
497                 &self.bytes
498         }
499 }
500
501 impl RefundContents {
502         pub fn description(&self) -> PrintableString {
503                 PrintableString(&self.description)
504         }
505
506         #[cfg(feature = "std")]
507         pub(super) fn is_expired(&self) -> bool {
508                 match self.absolute_expiry {
509                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
510                                 Ok(elapsed) => elapsed > seconds_from_epoch,
511                                 Err(_) => false,
512                         },
513                         None => false,
514                 }
515         }
516
517         pub(super) fn metadata(&self) -> &[u8] {
518                 self.payer.0.as_bytes().map(|bytes| bytes.as_slice()).unwrap_or(&[])
519         }
520
521         pub(super) fn chain(&self) -> ChainHash {
522                 self.chain.unwrap_or_else(|| self.implied_chain())
523         }
524
525         pub fn implied_chain(&self) -> ChainHash {
526                 ChainHash::using_genesis_block(Network::Bitcoin)
527         }
528
529         pub(super) fn derives_keys(&self) -> bool {
530                 self.payer.0.derives_keys()
531         }
532
533         pub(super) fn payer_id(&self) -> PublicKey {
534                 self.payer_id
535         }
536
537         pub(super) fn as_tlv_stream(&self) -> RefundTlvStreamRef {
538                 let payer = PayerTlvStreamRef {
539                         metadata: self.payer.0.as_bytes(),
540                 };
541
542                 let offer = OfferTlvStreamRef {
543                         chains: None,
544                         metadata: None,
545                         currency: None,
546                         amount: None,
547                         description: Some(&self.description),
548                         features: None,
549                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
550                         paths: self.paths.as_ref(),
551                         issuer: self.issuer.as_ref(),
552                         quantity_max: None,
553                         node_id: None,
554                 };
555
556                 let features = {
557                         if self.features == InvoiceRequestFeatures::empty() { None }
558                         else { Some(&self.features) }
559                 };
560
561                 let invoice_request = InvoiceRequestTlvStreamRef {
562                         chain: self.chain.as_ref(),
563                         amount: Some(self.amount_msats),
564                         features,
565                         quantity: self.quantity,
566                         payer_id: Some(&self.payer_id),
567                         payer_note: self.payer_note.as_ref(),
568                 };
569
570                 (payer, offer, invoice_request)
571         }
572 }
573
574 impl Writeable for Refund {
575         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
576                 WithoutLength(&self.bytes).write(writer)
577         }
578 }
579
580 impl Writeable for RefundContents {
581         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
582                 self.as_tlv_stream().write(writer)
583         }
584 }
585
586 type RefundTlvStream = (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream);
587
588 type RefundTlvStreamRef<'a> = (
589         PayerTlvStreamRef<'a>,
590         OfferTlvStreamRef<'a>,
591         InvoiceRequestTlvStreamRef<'a>,
592 );
593
594 impl SeekReadable for RefundTlvStream {
595         fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
596                 let payer = SeekReadable::read(r)?;
597                 let offer = SeekReadable::read(r)?;
598                 let invoice_request = SeekReadable::read(r)?;
599
600                 Ok((payer, offer, invoice_request))
601         }
602 }
603
604 impl Bech32Encode for Refund {
605         const BECH32_HRP: &'static str = "lnr";
606 }
607
608 impl FromStr for Refund {
609         type Err = ParseError;
610
611         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
612                 Refund::from_bech32_str(s)
613         }
614 }
615
616 impl TryFrom<Vec<u8>> for Refund {
617         type Error = ParseError;
618
619         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
620                 let refund = ParsedMessage::<RefundTlvStream>::try_from(bytes)?;
621                 let ParsedMessage { bytes, tlv_stream } = refund;
622                 let contents = RefundContents::try_from(tlv_stream)?;
623
624                 Ok(Refund { bytes, contents })
625         }
626 }
627
628 impl TryFrom<RefundTlvStream> for RefundContents {
629         type Error = SemanticError;
630
631         fn try_from(tlv_stream: RefundTlvStream) -> Result<Self, Self::Error> {
632                 let (
633                         PayerTlvStream { metadata: payer_metadata },
634                         OfferTlvStream {
635                                 chains, metadata, currency, amount: offer_amount, description,
636                                 features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
637                         },
638                         InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
639                 ) = tlv_stream;
640
641                 let payer = match payer_metadata {
642                         None => return Err(SemanticError::MissingPayerMetadata),
643                         Some(metadata) => PayerContents(Metadata::Bytes(metadata)),
644                 };
645
646                 if metadata.is_some() {
647                         return Err(SemanticError::UnexpectedMetadata);
648                 }
649
650                 if chains.is_some() {
651                         return Err(SemanticError::UnexpectedChain);
652                 }
653
654                 if currency.is_some() || offer_amount.is_some() {
655                         return Err(SemanticError::UnexpectedAmount);
656                 }
657
658                 let description = match description {
659                         None => return Err(SemanticError::MissingDescription),
660                         Some(description) => description,
661                 };
662
663                 if offer_features.is_some() {
664                         return Err(SemanticError::UnexpectedFeatures);
665                 }
666
667                 let absolute_expiry = absolute_expiry.map(Duration::from_secs);
668
669                 if quantity_max.is_some() {
670                         return Err(SemanticError::UnexpectedQuantity);
671                 }
672
673                 if node_id.is_some() {
674                         return Err(SemanticError::UnexpectedSigningPubkey);
675                 }
676
677                 let amount_msats = match amount {
678                         None => return Err(SemanticError::MissingAmount),
679                         Some(amount_msats) if amount_msats > MAX_VALUE_MSAT => {
680                                 return Err(SemanticError::InvalidAmount);
681                         },
682                         Some(amount_msats) => amount_msats,
683                 };
684
685                 let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
686
687                 let payer_id = match payer_id {
688                         None => return Err(SemanticError::MissingPayerId),
689                         Some(payer_id) => payer_id,
690                 };
691
692                 Ok(RefundContents {
693                         payer, description, absolute_expiry, issuer, paths, chain, amount_msats, features,
694                         quantity, payer_id, payer_note,
695                 })
696         }
697 }
698
699 impl core::fmt::Display for Refund {
700         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
701                 self.fmt_bech32_str(f)
702         }
703 }
704
705 #[cfg(test)]
706 mod tests {
707         use super::{Refund, RefundBuilder, RefundTlvStreamRef};
708
709         use bitcoin::blockdata::constants::ChainHash;
710         use bitcoin::network::constants::Network;
711         use bitcoin::secp256k1::{KeyPair, Secp256k1, SecretKey};
712         use core::convert::TryFrom;
713         use core::time::Duration;
714         use crate::blinded_path::{BlindedHop, BlindedPath};
715         use crate::sign::KeyMaterial;
716         use crate::ln::features::{InvoiceRequestFeatures, OfferFeatures};
717         use crate::ln::inbound_payment::ExpandedKey;
718         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
719         use crate::offers::invoice_request::InvoiceRequestTlvStreamRef;
720         use crate::offers::offer::OfferTlvStreamRef;
721         use crate::offers::parse::{ParseError, SemanticError};
722         use crate::offers::payer::PayerTlvStreamRef;
723         use crate::offers::test_utils::*;
724         use crate::util::ser::{BigSize, Writeable};
725         use crate::util::string::PrintableString;
726
727         trait ToBytes {
728                 fn to_bytes(&self) -> Vec<u8>;
729         }
730
731         impl<'a> ToBytes for RefundTlvStreamRef<'a> {
732                 fn to_bytes(&self) -> Vec<u8> {
733                         let mut buffer = Vec::new();
734                         self.write(&mut buffer).unwrap();
735                         buffer
736                 }
737         }
738
739         #[test]
740         fn builds_refund_with_defaults() {
741                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
742                         .build().unwrap();
743
744                 let mut buffer = Vec::new();
745                 refund.write(&mut buffer).unwrap();
746
747                 assert_eq!(refund.bytes, buffer.as_slice());
748                 assert_eq!(refund.metadata(), &[1; 32]);
749                 assert_eq!(refund.description(), PrintableString("foo"));
750                 assert_eq!(refund.absolute_expiry(), None);
751                 #[cfg(feature = "std")]
752                 assert!(!refund.is_expired());
753                 assert_eq!(refund.paths(), &[]);
754                 assert_eq!(refund.issuer(), None);
755                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Bitcoin));
756                 assert_eq!(refund.amount_msats(), 1000);
757                 assert_eq!(refund.features(), &InvoiceRequestFeatures::empty());
758                 assert_eq!(refund.payer_id(), payer_pubkey());
759                 assert_eq!(refund.payer_note(), None);
760
761                 assert_eq!(
762                         refund.as_tlv_stream(),
763                         (
764                                 PayerTlvStreamRef { metadata: Some(&vec![1; 32]) },
765                                 OfferTlvStreamRef {
766                                         chains: None,
767                                         metadata: None,
768                                         currency: None,
769                                         amount: None,
770                                         description: Some(&String::from("foo")),
771                                         features: None,
772                                         absolute_expiry: None,
773                                         paths: None,
774                                         issuer: None,
775                                         quantity_max: None,
776                                         node_id: None,
777                                 },
778                                 InvoiceRequestTlvStreamRef {
779                                         chain: None,
780                                         amount: Some(1000),
781                                         features: None,
782                                         quantity: None,
783                                         payer_id: Some(&payer_pubkey()),
784                                         payer_note: None,
785                                 },
786                         ),
787                 );
788
789                 if let Err(e) = Refund::try_from(buffer) {
790                         panic!("error parsing refund: {:?}", e);
791                 }
792         }
793
794         #[test]
795         fn fails_building_refund_with_invalid_amount() {
796                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), MAX_VALUE_MSAT + 1) {
797                         Ok(_) => panic!("expected error"),
798                         Err(e) => assert_eq!(e, SemanticError::InvalidAmount),
799                 }
800         }
801
802         #[test]
803         fn builds_refund_with_metadata_derived() {
804                 let desc = "foo".to_string();
805                 let node_id = payer_pubkey();
806                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
807                 let entropy = FixedEntropy {};
808                 let secp_ctx = Secp256k1::new();
809
810                 let refund = RefundBuilder
811                         ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000)
812                         .unwrap()
813                         .build().unwrap();
814                 assert_eq!(refund.payer_id(), node_id);
815
816                 // Fails verification with altered fields
817                 let invoice = refund
818                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
819                         .unwrap()
820                         .build().unwrap()
821                         .sign(recipient_sign).unwrap();
822                 assert!(invoice.verify(&expanded_key, &secp_ctx));
823
824                 let mut tlv_stream = refund.as_tlv_stream();
825                 tlv_stream.2.amount = Some(2000);
826
827                 let mut encoded_refund = Vec::new();
828                 tlv_stream.write(&mut encoded_refund).unwrap();
829
830                 let invoice = Refund::try_from(encoded_refund).unwrap()
831                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
832                         .unwrap()
833                         .build().unwrap()
834                         .sign(recipient_sign).unwrap();
835                 assert!(!invoice.verify(&expanded_key, &secp_ctx));
836
837                 // Fails verification with altered metadata
838                 let mut tlv_stream = refund.as_tlv_stream();
839                 let metadata = tlv_stream.0.metadata.unwrap().iter().copied().rev().collect();
840                 tlv_stream.0.metadata = Some(&metadata);
841
842                 let mut encoded_refund = Vec::new();
843                 tlv_stream.write(&mut encoded_refund).unwrap();
844
845                 let invoice = Refund::try_from(encoded_refund).unwrap()
846                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
847                         .unwrap()
848                         .build().unwrap()
849                         .sign(recipient_sign).unwrap();
850                 assert!(!invoice.verify(&expanded_key, &secp_ctx));
851         }
852
853         #[test]
854         fn builds_refund_with_derived_payer_id() {
855                 let desc = "foo".to_string();
856                 let node_id = payer_pubkey();
857                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
858                 let entropy = FixedEntropy {};
859                 let secp_ctx = Secp256k1::new();
860
861                 let blinded_path = BlindedPath {
862                         introduction_node_id: pubkey(40),
863                         blinding_point: pubkey(41),
864                         blinded_hops: vec![
865                                 BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
866                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
867                         ],
868                 };
869
870                 let refund = RefundBuilder
871                         ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000)
872                         .unwrap()
873                         .path(blinded_path)
874                         .build().unwrap();
875                 assert_ne!(refund.payer_id(), node_id);
876
877                 let invoice = refund
878                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
879                         .unwrap()
880                         .build().unwrap()
881                         .sign(recipient_sign).unwrap();
882                 assert!(invoice.verify(&expanded_key, &secp_ctx));
883
884                 // Fails verification with altered fields
885                 let mut tlv_stream = refund.as_tlv_stream();
886                 tlv_stream.2.amount = Some(2000);
887
888                 let mut encoded_refund = Vec::new();
889                 tlv_stream.write(&mut encoded_refund).unwrap();
890
891                 let invoice = Refund::try_from(encoded_refund).unwrap()
892                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
893                         .unwrap()
894                         .build().unwrap()
895                         .sign(recipient_sign).unwrap();
896                 assert!(!invoice.verify(&expanded_key, &secp_ctx));
897
898                 // Fails verification with altered payer_id
899                 let mut tlv_stream = refund.as_tlv_stream();
900                 let payer_id = pubkey(1);
901                 tlv_stream.2.payer_id = Some(&payer_id);
902
903                 let mut encoded_refund = Vec::new();
904                 tlv_stream.write(&mut encoded_refund).unwrap();
905
906                 let invoice = Refund::try_from(encoded_refund).unwrap()
907                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
908                         .unwrap()
909                         .build().unwrap()
910                         .sign(recipient_sign).unwrap();
911                 assert!(!invoice.verify(&expanded_key, &secp_ctx));
912         }
913
914         #[test]
915         fn builds_refund_with_absolute_expiry() {
916                 let future_expiry = Duration::from_secs(u64::max_value());
917                 let past_expiry = Duration::from_secs(0);
918
919                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
920                         .absolute_expiry(future_expiry)
921                         .build()
922                         .unwrap();
923                 let (_, tlv_stream, _) = refund.as_tlv_stream();
924                 #[cfg(feature = "std")]
925                 assert!(!refund.is_expired());
926                 assert_eq!(refund.absolute_expiry(), Some(future_expiry));
927                 assert_eq!(tlv_stream.absolute_expiry, Some(future_expiry.as_secs()));
928
929                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
930                         .absolute_expiry(future_expiry)
931                         .absolute_expiry(past_expiry)
932                         .build()
933                         .unwrap();
934                 let (_, tlv_stream, _) = refund.as_tlv_stream();
935                 #[cfg(feature = "std")]
936                 assert!(refund.is_expired());
937                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
938                 assert_eq!(tlv_stream.absolute_expiry, Some(past_expiry.as_secs()));
939         }
940
941         #[test]
942         fn builds_refund_with_paths() {
943                 let paths = vec![
944                         BlindedPath {
945                                 introduction_node_id: pubkey(40),
946                                 blinding_point: pubkey(41),
947                                 blinded_hops: vec![
948                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
949                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
950                                 ],
951                         },
952                         BlindedPath {
953                                 introduction_node_id: pubkey(40),
954                                 blinding_point: pubkey(41),
955                                 blinded_hops: vec![
956                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
957                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
958                                 ],
959                         },
960                 ];
961
962                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
963                         .path(paths[0].clone())
964                         .path(paths[1].clone())
965                         .build()
966                         .unwrap();
967                 let (_, offer_tlv_stream, invoice_request_tlv_stream) = refund.as_tlv_stream();
968                 assert_eq!(refund.paths(), paths.as_slice());
969                 assert_eq!(refund.payer_id(), pubkey(42));
970                 assert_ne!(pubkey(42), pubkey(44));
971                 assert_eq!(offer_tlv_stream.paths, Some(&paths));
972                 assert_eq!(invoice_request_tlv_stream.payer_id, Some(&pubkey(42)));
973         }
974
975         #[test]
976         fn builds_refund_with_issuer() {
977                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
978                         .issuer("bar".into())
979                         .build()
980                         .unwrap();
981                 let (_, tlv_stream, _) = refund.as_tlv_stream();
982                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
983                 assert_eq!(tlv_stream.issuer, Some(&String::from("bar")));
984
985                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
986                         .issuer("bar".into())
987                         .issuer("baz".into())
988                         .build()
989                         .unwrap();
990                 let (_, tlv_stream, _) = refund.as_tlv_stream();
991                 assert_eq!(refund.issuer(), Some(PrintableString("baz")));
992                 assert_eq!(tlv_stream.issuer, Some(&String::from("baz")));
993         }
994
995         #[test]
996         fn builds_refund_with_chain() {
997                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
998                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
999
1000                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1001                         .chain(Network::Bitcoin)
1002                         .build().unwrap();
1003                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1004                 assert_eq!(refund.chain(), mainnet);
1005                 assert_eq!(tlv_stream.chain, None);
1006
1007                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1008                         .chain(Network::Testnet)
1009                         .build().unwrap();
1010                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1011                 assert_eq!(refund.chain(), testnet);
1012                 assert_eq!(tlv_stream.chain, Some(&testnet));
1013
1014                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1015                         .chain(Network::Regtest)
1016                         .chain(Network::Testnet)
1017                         .build().unwrap();
1018                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1019                 assert_eq!(refund.chain(), testnet);
1020                 assert_eq!(tlv_stream.chain, Some(&testnet));
1021         }
1022
1023         #[test]
1024         fn builds_refund_with_quantity() {
1025                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1026                         .quantity(10)
1027                         .build().unwrap();
1028                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1029                 assert_eq!(refund.quantity(), Some(10));
1030                 assert_eq!(tlv_stream.quantity, Some(10));
1031
1032                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1033                         .quantity(10)
1034                         .quantity(1)
1035                         .build().unwrap();
1036                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1037                 assert_eq!(refund.quantity(), Some(1));
1038                 assert_eq!(tlv_stream.quantity, Some(1));
1039         }
1040
1041         #[test]
1042         fn builds_refund_with_payer_note() {
1043                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1044                         .payer_note("bar".into())
1045                         .build().unwrap();
1046                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1047                 assert_eq!(refund.payer_note(), Some(PrintableString("bar")));
1048                 assert_eq!(tlv_stream.payer_note, Some(&String::from("bar")));
1049
1050                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1051                         .payer_note("bar".into())
1052                         .payer_note("baz".into())
1053                         .build().unwrap();
1054                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1055                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
1056                 assert_eq!(tlv_stream.payer_note, Some(&String::from("baz")));
1057         }
1058
1059         #[test]
1060         fn fails_responding_with_unknown_required_features() {
1061                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1062                         .features_unchecked(InvoiceRequestFeatures::unknown())
1063                         .build().unwrap()
1064                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1065                 {
1066                         Ok(_) => panic!("expected error"),
1067                         Err(e) => assert_eq!(e, SemanticError::UnknownRequiredFeatures),
1068                 }
1069         }
1070
1071         #[test]
1072         fn parses_refund_with_metadata() {
1073                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1074                         .build().unwrap();
1075                 if let Err(e) = refund.to_string().parse::<Refund>() {
1076                         panic!("error parsing refund: {:?}", e);
1077                 }
1078
1079                 let mut tlv_stream = refund.as_tlv_stream();
1080                 tlv_stream.0.metadata = None;
1081
1082                 match Refund::try_from(tlv_stream.to_bytes()) {
1083                         Ok(_) => panic!("expected error"),
1084                         Err(e) => {
1085                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingPayerMetadata));
1086                         },
1087                 }
1088         }
1089
1090         #[test]
1091         fn parses_refund_with_description() {
1092                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1093                         .build().unwrap();
1094                 if let Err(e) = refund.to_string().parse::<Refund>() {
1095                         panic!("error parsing refund: {:?}", e);
1096                 }
1097
1098                 let mut tlv_stream = refund.as_tlv_stream();
1099                 tlv_stream.1.description = None;
1100
1101                 match Refund::try_from(tlv_stream.to_bytes()) {
1102                         Ok(_) => panic!("expected error"),
1103                         Err(e) => {
1104                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingDescription));
1105                         },
1106                 }
1107         }
1108
1109         #[test]
1110         fn parses_refund_with_amount() {
1111                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1112                         .build().unwrap();
1113                 if let Err(e) = refund.to_string().parse::<Refund>() {
1114                         panic!("error parsing refund: {:?}", e);
1115                 }
1116
1117                 let mut tlv_stream = refund.as_tlv_stream();
1118                 tlv_stream.2.amount = None;
1119
1120                 match Refund::try_from(tlv_stream.to_bytes()) {
1121                         Ok(_) => panic!("expected error"),
1122                         Err(e) => {
1123                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingAmount));
1124                         },
1125                 }
1126
1127                 let mut tlv_stream = refund.as_tlv_stream();
1128                 tlv_stream.2.amount = Some(MAX_VALUE_MSAT + 1);
1129
1130                 match Refund::try_from(tlv_stream.to_bytes()) {
1131                         Ok(_) => panic!("expected error"),
1132                         Err(e) => {
1133                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::InvalidAmount));
1134                         },
1135                 }
1136         }
1137
1138         #[test]
1139         fn parses_refund_with_payer_id() {
1140                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1141                         .build().unwrap();
1142                 if let Err(e) = refund.to_string().parse::<Refund>() {
1143                         panic!("error parsing refund: {:?}", e);
1144                 }
1145
1146                 let mut tlv_stream = refund.as_tlv_stream();
1147                 tlv_stream.2.payer_id = None;
1148
1149                 match Refund::try_from(tlv_stream.to_bytes()) {
1150                         Ok(_) => panic!("expected error"),
1151                         Err(e) => {
1152                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingPayerId));
1153                         },
1154                 }
1155         }
1156
1157         #[test]
1158         fn parses_refund_with_optional_fields() {
1159                 let past_expiry = Duration::from_secs(0);
1160                 let paths = vec![
1161                         BlindedPath {
1162                                 introduction_node_id: pubkey(40),
1163                                 blinding_point: pubkey(41),
1164                                 blinded_hops: vec![
1165                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1166                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1167                                 ],
1168                         },
1169                         BlindedPath {
1170                                 introduction_node_id: pubkey(40),
1171                                 blinding_point: pubkey(41),
1172                                 blinded_hops: vec![
1173                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1174                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1175                                 ],
1176                         },
1177                 ];
1178
1179                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1180                         .absolute_expiry(past_expiry)
1181                         .issuer("bar".into())
1182                         .path(paths[0].clone())
1183                         .path(paths[1].clone())
1184                         .chain(Network::Testnet)
1185                         .features_unchecked(InvoiceRequestFeatures::unknown())
1186                         .quantity(10)
1187                         .payer_note("baz".into())
1188                         .build()
1189                         .unwrap();
1190                 match refund.to_string().parse::<Refund>() {
1191                         Ok(refund) => {
1192                                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
1193                                 #[cfg(feature = "std")]
1194                                 assert!(refund.is_expired());
1195                                 assert_eq!(refund.paths(), &paths[..]);
1196                                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
1197                                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Testnet));
1198                                 assert_eq!(refund.features(), &InvoiceRequestFeatures::unknown());
1199                                 assert_eq!(refund.quantity(), Some(10));
1200                                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
1201                         },
1202                         Err(e) => panic!("error parsing refund: {:?}", e),
1203                 }
1204         }
1205
1206         #[test]
1207         fn fails_parsing_refund_with_unexpected_fields() {
1208                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1209                         .build().unwrap();
1210                 if let Err(e) = refund.to_string().parse::<Refund>() {
1211                         panic!("error parsing refund: {:?}", e);
1212                 }
1213
1214                 let metadata = vec![42; 32];
1215                 let mut tlv_stream = refund.as_tlv_stream();
1216                 tlv_stream.1.metadata = Some(&metadata);
1217
1218                 match Refund::try_from(tlv_stream.to_bytes()) {
1219                         Ok(_) => panic!("expected error"),
1220                         Err(e) => {
1221                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedMetadata));
1222                         },
1223                 }
1224
1225                 let chains = vec![ChainHash::using_genesis_block(Network::Testnet)];
1226                 let mut tlv_stream = refund.as_tlv_stream();
1227                 tlv_stream.1.chains = Some(&chains);
1228
1229                 match Refund::try_from(tlv_stream.to_bytes()) {
1230                         Ok(_) => panic!("expected error"),
1231                         Err(e) => {
1232                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedChain));
1233                         },
1234                 }
1235
1236                 let mut tlv_stream = refund.as_tlv_stream();
1237                 tlv_stream.1.currency = Some(&b"USD");
1238                 tlv_stream.1.amount = Some(1000);
1239
1240                 match Refund::try_from(tlv_stream.to_bytes()) {
1241                         Ok(_) => panic!("expected error"),
1242                         Err(e) => {
1243                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedAmount));
1244                         },
1245                 }
1246
1247                 let features = OfferFeatures::unknown();
1248                 let mut tlv_stream = refund.as_tlv_stream();
1249                 tlv_stream.1.features = Some(&features);
1250
1251                 match Refund::try_from(tlv_stream.to_bytes()) {
1252                         Ok(_) => panic!("expected error"),
1253                         Err(e) => {
1254                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedFeatures));
1255                         },
1256                 }
1257
1258                 let mut tlv_stream = refund.as_tlv_stream();
1259                 tlv_stream.1.quantity_max = Some(10);
1260
1261                 match Refund::try_from(tlv_stream.to_bytes()) {
1262                         Ok(_) => panic!("expected error"),
1263                         Err(e) => {
1264                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedQuantity));
1265                         },
1266                 }
1267
1268                 let node_id = payer_pubkey();
1269                 let mut tlv_stream = refund.as_tlv_stream();
1270                 tlv_stream.1.node_id = Some(&node_id);
1271
1272                 match Refund::try_from(tlv_stream.to_bytes()) {
1273                         Ok(_) => panic!("expected error"),
1274                         Err(e) => {
1275                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedSigningPubkey));
1276                         },
1277                 }
1278         }
1279
1280         #[test]
1281         fn fails_parsing_refund_with_extra_tlv_records() {
1282                 let secp_ctx = Secp256k1::new();
1283                 let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
1284                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], keys.public_key(), 1000).unwrap()
1285                         .build().unwrap();
1286
1287                 let mut encoded_refund = Vec::new();
1288                 refund.write(&mut encoded_refund).unwrap();
1289                 BigSize(1002).write(&mut encoded_refund).unwrap();
1290                 BigSize(32).write(&mut encoded_refund).unwrap();
1291                 [42u8; 32].write(&mut encoded_refund).unwrap();
1292
1293                 match Refund::try_from(encoded_refund) {
1294                         Ok(_) => panic!("expected error"),
1295                         Err(e) => assert_eq!(e, ParseError::Decode(DecodeError::InvalidValue)),
1296                 }
1297         }
1298 }