_ Git - rust-lightning/blob - 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 //! ```ignore
  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::onion_message::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;
  77 use core::convert::TryFrom;
  78 use core::str::FromStr;
  79 use core::time::Duration;
  80 use crate::io;
  81 use crate::ln::PaymentHash;
  82 use crate::ln::features::InvoiceRequestFeatures;
  83 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
  84 use crate::offers::invoice::{BlindedPayInfo, InvoiceBuilder};
  85 use crate::offers::invoice_request::{InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef};
  86 use crate::offers::offer::{OfferTlvStream, OfferTlvStreamRef};
  87 use crate::offers::parse::{Bech32Encode, ParseError, ParsedMessage, SemanticError};
  88 use crate::offers::payer::{PayerContents, PayerTlvStream, PayerTlvStreamRef};
  89 use crate::onion_message::BlindedPath;
  90 use crate::util::ser::{SeekReadable, WithoutLength, Writeable, Writer};
  91 use crate::util::string::PrintableString;
  92
  93 use crate::prelude::*;
  94
  95 #[cfg(feature = "std")]
  96 use std::time::SystemTime;
  97
  98 /// Builds a [`Refund`] for the "offer for money" flow.
  99 ///
 100 /// See [module-level documentation] for usage.
 101 ///
 102 /// [module-level documentation]: self
 103 pub struct RefundBuilder {
 104         refund: RefundContents,
 105 }
 106
 107 impl RefundBuilder {
 108         /// Creates a new builder for a refund using the [`Refund::payer_id`] for the public node id to
 109         /// send to if no [`Refund::paths`] are set. Otherwise, it may be a transient pubkey.
 110         ///
 111         /// Additionally, sets the required [`Refund::description`], [`Refund::metadata`], and
 112         /// [`Refund::amount_msats`].
 113         pub fn new(
 114                 description: String, metadata: Vec<u8>, payer_id: PublicKey, amount_msats: u64
 115         ) -> Result<Self, SemanticError> {
 116                 if amount_msats > MAX_VALUE_MSAT {
 117                         return Err(SemanticError::InvalidAmount);
 118                 }
 119
 120                 let refund = RefundContents {
 121                         payer: PayerContents(metadata), metadata: None, description, absolute_expiry: None,
 122                         issuer: None, paths: None, chain: None, amount_msats,
 123                         features: InvoiceRequestFeatures::empty(), payer_id, payer_note: None,
 124                 };
 125
 126                 Ok(RefundBuilder { refund })
 127         }
 128
 129         /// Sets the [`Refund::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
 130         /// already passed is valid and can be checked for using [`Refund::is_expired`].
 131         ///
 132         /// Successive calls to this method will override the previous setting.
 133         pub fn absolute_expiry(mut self, absolute_expiry: Duration) -> Self {
 134                 self.refund.absolute_expiry = Some(absolute_expiry);
 135                 self
 136         }
 137
 138         /// Sets the [`Refund::issuer`].
 139         ///
 140         /// Successive calls to this method will override the previous setting.
 141         pub fn issuer(mut self, issuer: String) -> Self {
 142                 self.refund.issuer = Some(issuer);
 143                 self
 144         }
 145
 146         /// Adds a blinded path to [`Refund::paths`]. Must include at least one path if only connected
 147         /// by private channels or if [`Refund::payer_id`] is not a public node id.
 148         ///
 149         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 150         /// adding duplicate paths.
 151         pub fn path(mut self, path: BlindedPath) -> Self {
 152                 self.refund.paths.get_or_insert_with(Vec::new).push(path);
 153                 self
 154         }
 155
 156         /// Sets the [`Refund::chain`] of the given [`Network`] for paying an invoice. If not
 157         /// called, [`Network::Bitcoin`] is assumed.
 158         ///
 159         /// Successive calls to this method will override the previous setting.
 160         pub fn chain(mut self, network: Network) -> Self {
 161                 self.refund.chain = Some(ChainHash::using_genesis_block(network));
 162                 self
 163         }
 164
 165         /// Sets the [`Refund::payer_note`].
 166         ///
 167         /// Successive calls to this method will override the previous setting.
 168         pub fn payer_note(mut self, payer_note: String) -> Self {
 169                 self.refund.payer_note = Some(payer_note);
 170                 self
 171         }
 172
 173         /// Builds a [`Refund`] after checking for valid semantics.
 174         pub fn build(mut self) -> Result<Refund, SemanticError> {
 175                 if self.refund.chain() == self.refund.implied_chain() {
 176                         self.refund.chain = None;
 177                 }
 178
 179                 let mut bytes = Vec::new();
 180                 self.refund.write(&mut bytes).unwrap();
 181
 182                 Ok(Refund {
 183                         bytes,
 184                         contents: self.refund,
 185                 })
 186         }
 187 }
 188
 189 #[cfg(test)]
 190 impl RefundBuilder {
 191         fn features_unchecked(mut self, features: InvoiceRequestFeatures) -> Self {
 192                 self.refund.features = features;
 193                 self
 194         }
 195 }
 196
 197 /// A `Refund` is a request to send an [`Invoice`] without a preceding [`Offer`].
 198 ///
 199 /// Typically, after an invoice is paid, the recipient may publish a refund allowing the sender to
 200 /// recoup their funds. A refund may be used more generally as an "offer for money", such as with a
 201 /// bitcoin ATM.
 202 ///
 203 /// [`Invoice`]: crate::offers::invoice::Invoice
 204 /// [`Offer`]: crate::offers::offer::Offer
 205 #[derive(Clone, Debug)]
 206 pub struct Refund {
 207         pub(super) bytes: Vec<u8>,
 208         pub(super) contents: RefundContents,
 209 }
 210
 211 /// The contents of a [`Refund`], which may be shared with an [`Invoice`].
 212 ///
 213 /// [`Invoice`]: crate::offers::invoice::Invoice
 214 #[derive(Clone, Debug)]
 215 pub(super) struct RefundContents {
 216         payer: PayerContents,
 217         // offer fields
 218         metadata: Option<Vec<u8>>,
 219         description: String,
 220         absolute_expiry: Option<Duration>,
 221         issuer: Option<String>,
 222         paths: Option<Vec<BlindedPath>>,
 223         // invoice_request fields
 224         chain: Option<ChainHash>,
 225         amount_msats: u64,
 226         features: InvoiceRequestFeatures,
 227         payer_id: PublicKey,
 228         payer_note: Option<String>,
 229 }
 230
 231 impl Refund {
 232         /// A complete description of the purpose of the refund. Intended to be displayed to the user
 233         /// but with the caveat that it has not been verified in any way.
 234         pub fn description(&self) -> PrintableString {
 235                 PrintableString(&self.contents.description)
 236         }
 237
 238         /// Duration since the Unix epoch when an invoice should no longer be sent.
 239         ///
 240         /// If `None`, the refund does not expire.
 241         pub fn absolute_expiry(&self) -> Option<Duration> {
 242                 self.contents.absolute_expiry
 243         }
 244
 245         /// Whether the refund has expired.
 246         #[cfg(feature = "std")]
 247         pub fn is_expired(&self) -> bool {
 248                 self.contents.is_expired()
 249         }
 250
 251         /// The issuer of the refund, possibly beginning with `user@domain` or `domain`. Intended to be
 252         /// displayed to the user but with the caveat that it has not been verified in any way.
 253         pub fn issuer(&self) -> Option<PrintableString> {
 254                 self.contents.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 255         }
 256
 257         /// Paths to the sender originating from publicly reachable nodes. Blinded paths provide sender
 258         /// privacy by obfuscating its node id.
 259         pub fn paths(&self) -> &[BlindedPath] {
 260                 self.contents.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 261         }
 262
 263         /// An unpredictable series of bytes, typically containing information about the derivation of
 264         /// [`payer_id`].
 265         ///
 266         /// [`payer_id`]: Self::payer_id
 267         pub fn metadata(&self) -> &[u8] {
 268                 &self.contents.payer.0
 269         }
 270
 271         /// A chain that the refund is valid for.
 272         pub fn chain(&self) -> ChainHash {
 273                 self.contents.chain.unwrap_or_else(|| self.contents.implied_chain())
 274         }
 275
 276         /// The amount to refund in msats (i.e., the minimum lightning-payable unit for [`chain`]).
 277         ///
 278         /// [`chain`]: Self::chain
 279         pub fn amount_msats(&self) -> u64 {
 280                 self.contents.amount_msats
 281         }
 282
 283         /// Features pertaining to requesting an invoice.
 284         pub fn features(&self) -> &InvoiceRequestFeatures {
 285                 &self.contents.features
 286         }
 287
 288         /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
 289         /// transient pubkey.
 290         ///
 291         /// [`paths`]: Self::paths
 292         pub fn payer_id(&self) -> PublicKey {
 293                 self.contents.payer_id
 294         }
 295
 296         /// Payer provided note to include in the invoice.
 297         pub fn payer_note(&self) -> Option<PrintableString> {
 298                 self.contents.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
 299         }
 300
 301         /// Creates an [`Invoice`] for the refund with the given required fields.
 302         ///
 303         /// Unless [`InvoiceBuilder::relative_expiry`] is set, the invoice will expire two hours after
 304         /// calling this method in `std` builds. For `no-std` builds, a final [`Duration`] parameter
 305         /// must be given, which is used to set [`Invoice::created_at`] since [`std::time::SystemTime`]
 306         /// is not available.
 307         ///
 308         /// The caller is expected to remember the preimage of `payment_hash` in order to
 309         /// claim a payment for the invoice.
 310         ///
 311         /// The `signing_pubkey` is required to sign the invoice since refunds are not in response to an
 312         /// offer, which does have a `signing_pubkey`.
 313         ///
 314         /// The `payment_paths` parameter is useful for maintaining the payment recipient's privacy. It
 315         /// must contain one or more elements.
 316         ///
 317         /// Errors if the request contains unknown required features.
 318         ///
 319         /// [`Invoice`]: crate::offers::invoice::Invoice
 320         /// [`Invoice::created_at`]: crate::offers::invoice::Invoice::created_at
 321         pub fn respond_with(
 322                 &self, payment_paths: Vec<(BlindedPath, BlindedPayInfo)>, payment_hash: PaymentHash,
 323                 signing_pubkey: PublicKey,
 324                 #[cfg(any(test, not(feature = "std")))]
 325                 created_at: Duration
 326         ) -> Result<InvoiceBuilder, SemanticError> {
 327                 if self.features().requires_unknown_bits() {
 328                         return Err(SemanticError::UnknownRequiredFeatures);
 329                 }
 330
 331                 #[cfg(all(not(test), feature = "std"))]
 332                 let created_at = std::time::SystemTime::now()
 333                         .duration_since(std::time::SystemTime::UNIX_EPOCH)
 334                         .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 335
 336                 InvoiceBuilder::for_refund(self, payment_paths, created_at, payment_hash, signing_pubkey)
 337         }
 338
 339         #[cfg(test)]
 340         fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 341                 self.contents.as_tlv_stream()
 342         }
 343 }
 344
 345 impl AsRef<[u8]> for Refund {
 346         fn as_ref(&self) -> &[u8] {
 347                 &self.bytes
 348         }
 349 }
 350
 351 impl RefundContents {
 352         #[cfg(feature = "std")]
 353         pub(super) fn is_expired(&self) -> bool {
 354                 match self.absolute_expiry {
 355                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
 356                                 Ok(elapsed) => elapsed > seconds_from_epoch,
 357                                 Err(_) => false,
 358                         },
 359                         None => false,
 360                 }
 361         }
 362
 363         pub(super) fn chain(&self) -> ChainHash {
 364                 self.chain.unwrap_or_else(|| self.implied_chain())
 365         }
 366
 367         pub fn implied_chain(&self) -> ChainHash {
 368                 ChainHash::using_genesis_block(Network::Bitcoin)
 369         }
 370
 371         pub(super) fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 372                 let payer = PayerTlvStreamRef {
 373                         metadata: Some(&self.payer.0),
 374                 };
 375
 376                 let offer = OfferTlvStreamRef {
 377                         chains: None,
 378                         metadata: self.metadata.as_ref(),
 379                         currency: None,
 380                         amount: None,
 381                         description: Some(&self.description),
 382                         features: None,
 383                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 384                         paths: self.paths.as_ref(),
 385                         issuer: self.issuer.as_ref(),
 386                         quantity_max: None,
 387                         node_id: None,
 388                 };
 389
 390                 let features = {
 391                         if self.features == InvoiceRequestFeatures::empty() { None }
 392                         else { Some(&self.features) }
 393                 };
 394
 395                 let invoice_request = InvoiceRequestTlvStreamRef {
 396                         chain: self.chain.as_ref(),
 397                         amount: Some(self.amount_msats),
 398                         features,
 399                         quantity: None,
 400                         payer_id: Some(&self.payer_id),
 401                         payer_note: self.payer_note.as_ref(),
 402                 };
 403
 404                 (payer, offer, invoice_request)
 405         }
 406 }
 407
 408 impl Writeable for Refund {
 409         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 410                 WithoutLength(&self.bytes).write(writer)
 411         }
 412 }
 413
 414 impl Writeable for RefundContents {
 415         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 416                 self.as_tlv_stream().write(writer)
 417         }
 418 }
 419
 420 type RefundTlvStream = (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream);
 421
 422 type RefundTlvStreamRef<'a> = (
 423         PayerTlvStreamRef<'a>,
 424         OfferTlvStreamRef<'a>,
 425         InvoiceRequestTlvStreamRef<'a>,
 426 );
 427
 428 impl SeekReadable for RefundTlvStream {
 429         fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
 430                 let payer = SeekReadable::read(r)?;
 431                 let offer = SeekReadable::read(r)?;
 432                 let invoice_request = SeekReadable::read(r)?;
 433
 434                 Ok((payer, offer, invoice_request))
 435         }
 436 }
 437
 438 impl Bech32Encode for Refund {
 439         const BECH32_HRP: &'static str = "lnr";
 440 }
 441
 442 impl FromStr for Refund {
 443         type Err = ParseError;
 444
 445         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 446                 Refund::from_bech32_str(s)
 447         }
 448 }
 449
 450 impl TryFrom<Vec<u8>> for Refund {
 451         type Error = ParseError;
 452
 453         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 454                 let refund = ParsedMessage::<RefundTlvStream>::try_from(bytes)?;
 455                 let ParsedMessage { bytes, tlv_stream } = refund;
 456                 let contents = RefundContents::try_from(tlv_stream)?;
 457
 458                 Ok(Refund { bytes, contents })
 459         }
 460 }
 461
 462 impl TryFrom<RefundTlvStream> for RefundContents {
 463         type Error = SemanticError;
 464
 465         fn try_from(tlv_stream: RefundTlvStream) -> Result<Self, Self::Error> {
 466                 let (
 467                         PayerTlvStream { metadata: payer_metadata },
 468                         OfferTlvStream {
 469                                 chains, metadata, currency, amount: offer_amount, description,
 470                                 features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
 471                         },
 472                         InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
 473                 ) = tlv_stream;
 474
 475                 let payer = match payer_metadata {
 476                         None => return Err(SemanticError::MissingPayerMetadata),
 477                         Some(metadata) => PayerContents(metadata),
 478                 };
 479
 480                 if chains.is_some() {
 481                         return Err(SemanticError::UnexpectedChain);
 482                 }
 483
 484                 if currency.is_some() || offer_amount.is_some() {
 485                         return Err(SemanticError::UnexpectedAmount);
 486                 }
 487
 488                 let description = match description {
 489                         None => return Err(SemanticError::MissingDescription),
 490                         Some(description) => description,
 491                 };
 492
 493                 if offer_features.is_some() {
 494                         return Err(SemanticError::UnexpectedFeatures);
 495                 }
 496
 497                 let absolute_expiry = absolute_expiry.map(Duration::from_secs);
 498
 499                 if quantity_max.is_some() {
 500                         return Err(SemanticError::UnexpectedQuantity);
 501                 }
 502
 503                 if node_id.is_some() {
 504                         return Err(SemanticError::UnexpectedSigningPubkey);
 505                 }
 506
 507                 let amount_msats = match amount {
 508                         None => return Err(SemanticError::MissingAmount),
 509                         Some(amount_msats) if amount_msats > MAX_VALUE_MSAT => {
 510                                 return Err(SemanticError::InvalidAmount);
 511                         },
 512                         Some(amount_msats) => amount_msats,
 513                 };
 514
 515                 let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
 516
 517                 // TODO: Check why this isn't in the spec.
 518                 if quantity.is_some() {
 519                         return Err(SemanticError::UnexpectedQuantity);
 520                 }
 521
 522                 let payer_id = match payer_id {
 523                         None => return Err(SemanticError::MissingPayerId),
 524                         Some(payer_id) => payer_id,
 525                 };
 526
 527                 // TODO: Should metadata be included?
 528                 Ok(RefundContents {
 529                         payer, metadata, description, absolute_expiry, issuer, paths, chain, amount_msats,
 530                         features, payer_id, payer_note,
 531                 })
 532         }
 533 }
 534
 535 impl core::fmt::Display for Refund {
 536         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 537                 self.fmt_bech32_str(f)
 538         }
 539 }
 540
 541 #[cfg(test)]
 542 mod tests {
 543         use super::{Refund, RefundBuilder, RefundTlvStreamRef};
 544
 545         use bitcoin::blockdata::constants::ChainHash;
 546         use bitcoin::network::constants::Network;
 547         use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
 548         use core::convert::TryFrom;
 549         use core::time::Duration;
 550         use crate::ln::features::{InvoiceRequestFeatures, OfferFeatures};
 551         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 552         use crate::offers::invoice_request::InvoiceRequestTlvStreamRef;
 553         use crate::offers::offer::OfferTlvStreamRef;
 554         use crate::offers::parse::{ParseError, SemanticError};
 555         use crate::offers::payer::PayerTlvStreamRef;
 556         use crate::onion_message::{BlindedHop, BlindedPath};
 557         use crate::util::ser::{BigSize, Writeable};
 558         use crate::util::string::PrintableString;
 559
 560         fn payer_pubkey() -> PublicKey {
 561                 let secp_ctx = Secp256k1::new();
 562                 KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()).public_key()
 563         }
 564
 565         fn pubkey(byte: u8) -> PublicKey {
 566                 let secp_ctx = Secp256k1::new();
 567                 PublicKey::from_secret_key(&secp_ctx, &privkey(byte))
 568         }
 569
 570         fn privkey(byte: u8) -> SecretKey {
 571                 SecretKey::from_slice(&[byte; 32]).unwrap()
 572         }
 573
 574         trait ToBytes {
 575                 fn to_bytes(&self) -> Vec<u8>;
 576         }
 577
 578         impl<'a> ToBytes for RefundTlvStreamRef<'a> {
 579                 fn to_bytes(&self) -> Vec<u8> {
 580                         let mut buffer = Vec::new();
 581                         self.write(&mut buffer).unwrap();
 582                         buffer
 583                 }
 584         }
 585
 586         #[test]
 587         fn builds_refund_with_defaults() {
 588                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 589                         .build().unwrap();
 590
 591                 let mut buffer = Vec::new();
 592                 refund.write(&mut buffer).unwrap();
 593
 594                 assert_eq!(refund.bytes, buffer.as_slice());
 595                 assert_eq!(refund.metadata(), &[1; 32]);
 596                 assert_eq!(refund.description(), PrintableString("foo"));
 597                 assert_eq!(refund.absolute_expiry(), None);
 598                 #[cfg(feature = "std")]
 599                 assert!(!refund.is_expired());
 600                 assert_eq!(refund.paths(), &[]);
 601                 assert_eq!(refund.issuer(), None);
 602                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Bitcoin));
 603                 assert_eq!(refund.amount_msats(), 1000);
 604                 assert_eq!(refund.features(), &InvoiceRequestFeatures::empty());
 605                 assert_eq!(refund.payer_id(), payer_pubkey());
 606                 assert_eq!(refund.payer_note(), None);
 607
 608                 assert_eq!(
 609                         refund.as_tlv_stream(),
 610                         (
 611                                 PayerTlvStreamRef { metadata: Some(&vec![1; 32]) },
 612                                 OfferTlvStreamRef {
 613                                         chains: None,
 614                                         metadata: None,
 615                                         currency: None,
 616                                         amount: None,
 617                                         description: Some(&String::from("foo")),
 618                                         features: None,
 619                                         absolute_expiry: None,
 620                                         paths: None,
 621                                         issuer: None,
 622                                         quantity_max: None,
 623                                         node_id: None,
 624                                 },
 625                                 InvoiceRequestTlvStreamRef {
 626                                         chain: None,
 627                                         amount: Some(1000),
 628                                         features: None,
 629                                         quantity: None,
 630                                         payer_id: Some(&payer_pubkey()),
 631                                         payer_note: None,
 632                                 },
 633                         ),
 634                 );
 635
 636                 if let Err(e) = Refund::try_from(buffer) {
 637                         panic!("error parsing refund: {:?}", e);
 638                 }
 639         }
 640
 641         #[test]
 642         fn fails_building_refund_with_invalid_amount() {
 643                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), MAX_VALUE_MSAT + 1) {
 644                         Ok(_) => panic!("expected error"),
 645                         Err(e) => assert_eq!(e, SemanticError::InvalidAmount),
 646                 }
 647         }
 648
 649         #[test]
 650         fn builds_refund_with_absolute_expiry() {
 651                 let future_expiry = Duration::from_secs(u64::max_value());
 652                 let past_expiry = Duration::from_secs(0);
 653
 654                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 655                         .absolute_expiry(future_expiry)
 656                         .build()
 657                         .unwrap();
 658                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 659                 #[cfg(feature = "std")]
 660                 assert!(!refund.is_expired());
 661                 assert_eq!(refund.absolute_expiry(), Some(future_expiry));
 662                 assert_eq!(tlv_stream.absolute_expiry, Some(future_expiry.as_secs()));
 663
 664                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 665                         .absolute_expiry(future_expiry)
 666                         .absolute_expiry(past_expiry)
 667                         .build()
 668                         .unwrap();
 669                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 670                 #[cfg(feature = "std")]
 671                 assert!(refund.is_expired());
 672                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
 673                 assert_eq!(tlv_stream.absolute_expiry, Some(past_expiry.as_secs()));
 674         }
 675
 676         #[test]
 677         fn builds_refund_with_paths() {
 678                 let paths = vec![
 679                         BlindedPath {
 680                                 introduction_node_id: pubkey(40),
 681                                 blinding_point: pubkey(41),
 682                                 blinded_hops: vec![
 683                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
 684                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
 685                                 ],
 686                         },
 687                         BlindedPath {
 688                                 introduction_node_id: pubkey(40),
 689                                 blinding_point: pubkey(41),
 690                                 blinded_hops: vec![
 691                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
 692                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
 693                                 ],
 694                         },
 695                 ];
 696
 697                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 698                         .path(paths[0].clone())
 699                         .path(paths[1].clone())
 700                         .build()
 701                         .unwrap();
 702                 let (_, offer_tlv_stream, invoice_request_tlv_stream) = refund.as_tlv_stream();
 703                 assert_eq!(refund.paths(), paths.as_slice());
 704                 assert_eq!(refund.payer_id(), pubkey(42));
 705                 assert_ne!(pubkey(42), pubkey(44));
 706                 assert_eq!(offer_tlv_stream.paths, Some(&paths));
 707                 assert_eq!(invoice_request_tlv_stream.payer_id, Some(&pubkey(42)));
 708         }
 709
 710         #[test]
 711         fn builds_refund_with_issuer() {
 712                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 713                         .issuer("bar".into())
 714                         .build()
 715                         .unwrap();
 716                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 717                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
 718                 assert_eq!(tlv_stream.issuer, Some(&String::from("bar")));
 719
 720                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 721                         .issuer("bar".into())
 722                         .issuer("baz".into())
 723                         .build()
 724                         .unwrap();
 725                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 726                 assert_eq!(refund.issuer(), Some(PrintableString("baz")));
 727                 assert_eq!(tlv_stream.issuer, Some(&String::from("baz")));
 728         }
 729
 730         #[test]
 731         fn builds_refund_with_chain() {
 732                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
 733                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
 734
 735                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 736                         .chain(Network::Bitcoin)
 737                         .build().unwrap();
 738                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 739                 assert_eq!(refund.chain(), mainnet);
 740                 assert_eq!(tlv_stream.chain, None);
 741
 742                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 743                         .chain(Network::Testnet)
 744                         .build().unwrap();
 745                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 746                 assert_eq!(refund.chain(), testnet);
 747                 assert_eq!(tlv_stream.chain, Some(&testnet));
 748
 749                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 750                         .chain(Network::Regtest)
 751                         .chain(Network::Testnet)
 752                         .build().unwrap();
 753                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 754                 assert_eq!(refund.chain(), testnet);
 755                 assert_eq!(tlv_stream.chain, Some(&testnet));
 756         }
 757
 758         #[test]
 759         fn builds_refund_with_payer_note() {
 760                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 761                         .payer_note("bar".into())
 762                         .build().unwrap();
 763                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 764                 assert_eq!(refund.payer_note(), Some(PrintableString("bar")));
 765                 assert_eq!(tlv_stream.payer_note, Some(&String::from("bar")));
 766
 767                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 768                         .payer_note("bar".into())
 769                         .payer_note("baz".into())
 770                         .build().unwrap();
 771                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 772                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
 773                 assert_eq!(tlv_stream.payer_note, Some(&String::from("baz")));
 774         }
 775
 776         #[test]
 777         fn parses_refund_with_metadata() {
 778                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 779                         .build().unwrap();
 780                 if let Err(e) = refund.to_string().parse::<Refund>() {
 781                         panic!("error parsing refund: {:?}", e);
 782                 }
 783
 784                 let mut tlv_stream = refund.as_tlv_stream();
 785                 tlv_stream.0.metadata = None;
 786
 787                 match Refund::try_from(tlv_stream.to_bytes()) {
 788                         Ok(_) => panic!("expected error"),
 789                         Err(e) => {
 790                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingPayerMetadata));
 791                         },
 792                 }
 793         }
 794
 795         #[test]
 796         fn parses_refund_with_description() {
 797                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 798                         .build().unwrap();
 799                 if let Err(e) = refund.to_string().parse::<Refund>() {
 800                         panic!("error parsing refund: {:?}", e);
 801                 }
 802
 803                 let mut tlv_stream = refund.as_tlv_stream();
 804                 tlv_stream.1.description = None;
 805
 806                 match Refund::try_from(tlv_stream.to_bytes()) {
 807                         Ok(_) => panic!("expected error"),
 808                         Err(e) => {
 809                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingDescription));
 810                         },
 811                 }
 812         }
 813
 814         #[test]
 815         fn parses_refund_with_amount() {
 816                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 817                         .build().unwrap();
 818                 if let Err(e) = refund.to_string().parse::<Refund>() {
 819                         panic!("error parsing refund: {:?}", e);
 820                 }
 821
 822                 let mut tlv_stream = refund.as_tlv_stream();
 823                 tlv_stream.2.amount = None;
 824
 825                 match Refund::try_from(tlv_stream.to_bytes()) {
 826                         Ok(_) => panic!("expected error"),
 827                         Err(e) => {
 828                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingAmount));
 829                         },
 830                 }
 831
 832                 let mut tlv_stream = refund.as_tlv_stream();
 833                 tlv_stream.2.amount = Some(MAX_VALUE_MSAT + 1);
 834
 835                 match Refund::try_from(tlv_stream.to_bytes()) {
 836                         Ok(_) => panic!("expected error"),
 837                         Err(e) => {
 838                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::InvalidAmount));
 839                         },
 840                 }
 841         }
 842
 843         #[test]
 844         fn parses_refund_with_payer_id() {
 845                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 846                         .build().unwrap();
 847                 if let Err(e) = refund.to_string().parse::<Refund>() {
 848                         panic!("error parsing refund: {:?}", e);
 849                 }
 850
 851                 let mut tlv_stream = refund.as_tlv_stream();
 852                 tlv_stream.2.payer_id = None;
 853
 854                 match Refund::try_from(tlv_stream.to_bytes()) {
 855                         Ok(_) => panic!("expected error"),
 856                         Err(e) => {
 857                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingPayerId));
 858                         },
 859                 }
 860         }
 861
 862         #[test]
 863         fn parses_refund_with_optional_fields() {
 864                 let past_expiry = Duration::from_secs(0);
 865                 let paths = vec![
 866                         BlindedPath {
 867                                 introduction_node_id: pubkey(40),
 868                                 blinding_point: pubkey(41),
 869                                 blinded_hops: vec![
 870                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
 871                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
 872                                 ],
 873                         },
 874                         BlindedPath {
 875                                 introduction_node_id: pubkey(40),
 876                                 blinding_point: pubkey(41),
 877                                 blinded_hops: vec![
 878                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
 879                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
 880                                 ],
 881                         },
 882                 ];
 883
 884                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 885                         .absolute_expiry(past_expiry)
 886                         .issuer("bar".into())
 887                         .path(paths[0].clone())
 888                         .path(paths[1].clone())
 889                         .chain(Network::Testnet)
 890                         .features_unchecked(InvoiceRequestFeatures::unknown())
 891                         .payer_note("baz".into())
 892                         .build()
 893                         .unwrap();
 894                 match refund.to_string().parse::<Refund>() {
 895                         Ok(refund) => {
 896                                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
 897                                 #[cfg(feature = "std")]
 898                                 assert!(refund.is_expired());
 899                                 assert_eq!(refund.paths(), &paths[..]);
 900                                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
 901                                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Testnet));
 902                                 assert_eq!(refund.features(), &InvoiceRequestFeatures::unknown());
 903                                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
 904                         },
 905                         Err(e) => panic!("error parsing refund: {:?}", e),
 906                 }
 907         }
 908
 909         #[test]
 910         fn fails_parsing_refund_with_unexpected_fields() {
 911                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 912                         .build().unwrap();
 913                 if let Err(e) = refund.to_string().parse::<Refund>() {
 914                         panic!("error parsing refund: {:?}", e);
 915                 }
 916
 917                 let chains = vec![ChainHash::using_genesis_block(Network::Testnet)];
 918                 let mut tlv_stream = refund.as_tlv_stream();
 919                 tlv_stream.1.chains = Some(&chains);
 920
 921                 match Refund::try_from(tlv_stream.to_bytes()) {
 922                         Ok(_) => panic!("expected error"),
 923                         Err(e) => {
 924                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedChain));
 925                         },
 926                 }
 927
 928                 let mut tlv_stream = refund.as_tlv_stream();
 929                 tlv_stream.1.currency = Some(&b"USD");
 930                 tlv_stream.1.amount = Some(1000);
 931
 932                 match Refund::try_from(tlv_stream.to_bytes()) {
 933                         Ok(_) => panic!("expected error"),
 934                         Err(e) => {
 935                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedAmount));
 936                         },
 937                 }
 938
 939                 let features = OfferFeatures::unknown();
 940                 let mut tlv_stream = refund.as_tlv_stream();
 941                 tlv_stream.1.features = Some(&features);
 942
 943                 match Refund::try_from(tlv_stream.to_bytes()) {
 944                         Ok(_) => panic!("expected error"),
 945                         Err(e) => {
 946                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedFeatures));
 947                         },
 948                 }
 949
 950                 let mut tlv_stream = refund.as_tlv_stream();
 951                 tlv_stream.1.quantity_max = Some(10);
 952
 953                 match Refund::try_from(tlv_stream.to_bytes()) {
 954                         Ok(_) => panic!("expected error"),
 955                         Err(e) => {
 956                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedQuantity));
 957                         },
 958                 }
 959
 960                 let node_id = payer_pubkey();
 961                 let mut tlv_stream = refund.as_tlv_stream();
 962                 tlv_stream.1.node_id = Some(&node_id);
 963
 964                 match Refund::try_from(tlv_stream.to_bytes()) {
 965                         Ok(_) => panic!("expected error"),
 966                         Err(e) => {
 967                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedSigningPubkey));
 968                         },
 969                 }
 970
 971                 let mut tlv_stream = refund.as_tlv_stream();
 972                 tlv_stream.2.quantity = Some(10);
 973
 974                 match Refund::try_from(tlv_stream.to_bytes()) {
 975                         Ok(_) => panic!("expected error"),
 976                         Err(e) => {
 977                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedQuantity));
 978                         },
 979                 }
 980         }
 981
 982         #[test]
 983         fn fails_parsing_refund_with_extra_tlv_records() {
 984                 let secp_ctx = Secp256k1::new();
 985                 let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
 986                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], keys.public_key(), 1000).unwrap()
 987                         .build().unwrap();
 988
 989                 let mut encoded_refund = Vec::new();
 990                 refund.write(&mut encoded_refund).unwrap();
 991                 BigSize(1002).write(&mut encoded_refund).unwrap();
 992                 BigSize(32).write(&mut encoded_refund).unwrap();
 993                 [42u8; 32].write(&mut encoded_refund).unwrap();
 994
 995                 match Refund::try_from(encoded_refund) {
 996                         Ok(_) => panic!("expected error"),
 997                         Err(e) => assert_eq!(e, ParseError::Decode(DecodeError::InvalidValue)),
 998                 }
 999         }
1000 }