_ 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 //! [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
  18 //! [`Offer`]: crate::offers::offer::Offer
  19 //!
  20 //! ```ignore
  21 //! extern crate bitcoin;
  22 //! extern crate core;
  23 //! extern crate lightning;
  24 //!
  25 //! use core::convert::TryFrom;
  26 //! use core::time::Duration;
  27 //!
  28 //! use bitcoin::network::constants::Network;
  29 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
  30 //! use lightning::offers::parse::ParseError;
  31 //! use lightning::offers::refund::{Refund, RefundBuilder};
  32 //! use lightning::util::ser::{Readable, Writeable};
  33 //!
  34 //! # use lightning::onion_message::BlindedPath;
  35 //! # #[cfg(feature = "std")]
  36 //! # use std::time::SystemTime;
  37 //! #
  38 //! # fn create_blinded_path() -> BlindedPath { unimplemented!() }
  39 //! # fn create_another_blinded_path() -> BlindedPath { unimplemented!() }
  40 //! #
  41 //! # #[cfg(feature = "std")]
  42 //! # fn build() -> Result<(), ParseError> {
  43 //! let secp_ctx = Secp256k1::new();
  44 //! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
  45 //! let pubkey = PublicKey::from(keys);
  46 //!
  47 //! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
  48 //! let refund = RefundBuilder::new("coffee, large".to_string(), vec![1; 32], pubkey, 20_000)?
  49 //!     .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
  50 //!     .issuer("Foo Bar".to_string())
  51 //!     .path(create_blinded_path())
  52 //!     .path(create_another_blinded_path())
  53 //!     .chain(Network::Bitcoin)
  54 //!     .payer_note("refund for order #12345".to_string())
  55 //!     .build()?;
  56 //!
  57 //! // Encode as a bech32 string for use in a QR code.
  58 //! let encoded_refund = refund.to_string();
  59 //!
  60 //! // Parse from a bech32 string after scanning from a QR code.
  61 //! let refund = encoded_refund.parse::<Refund>()?;
  62 //!
  63 //! // Encode refund as raw bytes.
  64 //! let mut bytes = Vec::new();
  65 //! refund.write(&mut bytes).unwrap();
  66 //!
  67 //! // Decode raw bytes into an refund.
  68 //! let refund = Refund::try_from(bytes)?;
  69 //! # Ok(())
  70 //! # }
  71 //! ```
  72
  73 use bitcoin::blockdata::constants::ChainHash;
  74 use bitcoin::network::constants::Network;
  75 use bitcoin::secp256k1::PublicKey;
  76 use core::convert::TryFrom;
  77 use core::str::FromStr;
  78 use core::time::Duration;
  79 use crate::io;
  80 use crate::ln::features::InvoiceRequestFeatures;
  81 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
  82 use crate::offers::invoice_request::{InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef};
  83 use crate::offers::offer::{OfferTlvStream, OfferTlvStreamRef};
  84 use crate::offers::parse::{Bech32Encode, ParseError, ParsedMessage, SemanticError};
  85 use crate::offers::payer::{PayerContents, PayerTlvStream, PayerTlvStreamRef};
  86 use crate::onion_message::BlindedPath;
  87 use crate::util::ser::{SeekReadable, WithoutLength, Writeable, Writer};
  88 use crate::util::string::PrintableString;
  89
  90 use crate::prelude::*;
  91
  92 #[cfg(feature = "std")]
  93 use std::time::SystemTime;
  94
  95 /// Builds a [`Refund`] for the "offer for money" flow.
  96 ///
  97 /// See [module-level documentation] for usage.
  98 ///
  99 /// [module-level documentation]: self
 100 pub struct RefundBuilder {
 101         refund: RefundContents,
 102 }
 103
 104 impl RefundBuilder {
 105         /// Creates a new builder for a refund using the [`Refund::payer_id`] for signing invoices. Use
 106         /// a different pubkey per refund to avoid correlating refunds.
 107         ///
 108         /// Additionally, sets the required [`Refund::description`], [`Refund::metadata`], and
 109         /// [`Refund::amount_msats`].
 110         pub fn new(
 111                 description: String, metadata: Vec<u8>, payer_id: PublicKey, amount_msats: u64
 112         ) -> Result<Self, SemanticError> {
 113                 if amount_msats > MAX_VALUE_MSAT {
 114                         return Err(SemanticError::InvalidAmount);
 115                 }
 116
 117                 let refund = RefundContents {
 118                         payer: PayerContents(metadata), metadata: None, description, absolute_expiry: None,
 119                         issuer: None, paths: None, chain: None, amount_msats,
 120                         features: InvoiceRequestFeatures::empty(), payer_id, payer_note: None,
 121                 };
 122
 123                 Ok(RefundBuilder { refund })
 124         }
 125
 126         /// Sets the [`Refund::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
 127         /// already passed is valid and can be checked for using [`Refund::is_expired`].
 128         ///
 129         /// Successive calls to this method will override the previous setting.
 130         pub fn absolute_expiry(mut self, absolute_expiry: Duration) -> Self {
 131                 self.refund.absolute_expiry = Some(absolute_expiry);
 132                 self
 133         }
 134
 135         /// Sets the [`Refund::issuer`].
 136         ///
 137         /// Successive calls to this method will override the previous setting.
 138         pub fn issuer(mut self, issuer: String) -> Self {
 139                 self.refund.issuer = Some(issuer);
 140                 self
 141         }
 142
 143         /// Adds a blinded path to [`Refund::paths`]. Must include at least one path if only connected
 144         /// by private channels or if [`Refund::payer_id`] is not a public node id.
 145         ///
 146         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 147         /// adding duplicate paths.
 148         pub fn path(mut self, path: BlindedPath) -> Self {
 149                 self.refund.paths.get_or_insert_with(Vec::new).push(path);
 150                 self
 151         }
 152
 153         /// Sets the [`Refund::chain`] of the given [`Network`] for paying an invoice. If not
 154         /// called, [`Network::Bitcoin`] is assumed.
 155         ///
 156         /// Successive calls to this method will override the previous setting.
 157         pub fn chain(mut self, network: Network) -> Self {
 158                 self.refund.chain = Some(ChainHash::using_genesis_block(network));
 159                 self
 160         }
 161
 162         /// Sets the [`Refund::payer_note`].
 163         ///
 164         /// Successive calls to this method will override the previous setting.
 165         pub fn payer_note(mut self, payer_note: String) -> Self {
 166                 self.refund.payer_note = Some(payer_note);
 167                 self
 168         }
 169
 170         /// Builds a [`Refund`] after checking for valid semantics.
 171         pub fn build(mut self) -> Result<Refund, SemanticError> {
 172                 if self.refund.chain() == self.refund.implied_chain() {
 173                         self.refund.chain = None;
 174                 }
 175
 176                 let mut bytes = Vec::new();
 177                 self.refund.write(&mut bytes).unwrap();
 178
 179                 Ok(Refund {
 180                         bytes,
 181                         contents: self.refund,
 182                 })
 183         }
 184 }
 185
 186 #[cfg(test)]
 187 impl RefundBuilder {
 188         fn features_unchecked(mut self, features: InvoiceRequestFeatures) -> Self {
 189                 self.refund.features = features;
 190                 self
 191         }
 192 }
 193
 194 /// A `Refund` is a request to send an `Invoice` without a preceding [`Offer`].
 195 ///
 196 /// Typically, after an invoice is paid, the recipient may publish a refund allowing the sender to
 197 /// recoup their funds. A refund may be used more generally as an "offer for money", such as with a
 198 /// bitcoin ATM.
 199 ///
 200 /// [`Offer`]: crate::offers::offer::Offer
 201 #[derive(Clone, Debug)]
 202 pub struct Refund {
 203         bytes: Vec<u8>,
 204         contents: RefundContents,
 205 }
 206
 207 /// The contents of a [`Refund`], which may be shared with an `Invoice`.
 208 #[derive(Clone, Debug)]
 209 struct RefundContents {
 210         payer: PayerContents,
 211         // offer fields
 212         metadata: Option<Vec<u8>>,
 213         description: String,
 214         absolute_expiry: Option<Duration>,
 215         issuer: Option<String>,
 216         paths: Option<Vec<BlindedPath>>,
 217         // invoice_request fields
 218         chain: Option<ChainHash>,
 219         amount_msats: u64,
 220         features: InvoiceRequestFeatures,
 221         payer_id: PublicKey,
 222         payer_note: Option<String>,
 223 }
 224
 225 impl Refund {
 226         /// A complete description of the purpose of the refund. Intended to be displayed to the user
 227         /// but with the caveat that it has not been verified in any way.
 228         pub fn description(&self) -> PrintableString {
 229                 PrintableString(&self.contents.description)
 230         }
 231
 232         /// Duration since the Unix epoch when an invoice should no longer be sent.
 233         ///
 234         /// If `None`, the refund does not expire.
 235         pub fn absolute_expiry(&self) -> Option<Duration> {
 236                 self.contents.absolute_expiry
 237         }
 238
 239         /// Whether the refund has expired.
 240         #[cfg(feature = "std")]
 241         pub fn is_expired(&self) -> bool {
 242                 match self.absolute_expiry() {
 243                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
 244                                 Ok(elapsed) => elapsed > seconds_from_epoch,
 245                                 Err(_) => false,
 246                         },
 247                         None => false,
 248                 }
 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 possibly transient pubkey used to sign the refund.
 289         pub fn payer_id(&self) -> PublicKey {
 290                 self.contents.payer_id
 291         }
 292
 293         /// Payer provided note to include in the invoice.
 294         pub fn payer_note(&self) -> Option<PrintableString> {
 295                 self.contents.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
 296         }
 297
 298         #[cfg(test)]
 299         fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 300                 self.contents.as_tlv_stream()
 301         }
 302 }
 303
 304 impl AsRef<[u8]> for Refund {
 305         fn as_ref(&self) -> &[u8] {
 306                 &self.bytes
 307         }
 308 }
 309
 310 impl RefundContents {
 311         fn chain(&self) -> ChainHash {
 312                 self.chain.unwrap_or_else(|| self.implied_chain())
 313         }
 314
 315         pub fn implied_chain(&self) -> ChainHash {
 316                 ChainHash::using_genesis_block(Network::Bitcoin)
 317         }
 318
 319         pub(super) fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 320                 let payer = PayerTlvStreamRef {
 321                         metadata: Some(&self.payer.0),
 322                 };
 323
 324                 let offer = OfferTlvStreamRef {
 325                         chains: None,
 326                         metadata: self.metadata.as_ref(),
 327                         currency: None,
 328                         amount: None,
 329                         description: Some(&self.description),
 330                         features: None,
 331                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 332                         paths: self.paths.as_ref(),
 333                         issuer: self.issuer.as_ref(),
 334                         quantity_max: None,
 335                         node_id: None,
 336                 };
 337
 338                 let features = {
 339                         if self.features == InvoiceRequestFeatures::empty() { None }
 340                         else { Some(&self.features) }
 341                 };
 342
 343                 let invoice_request = InvoiceRequestTlvStreamRef {
 344                         chain: self.chain.as_ref(),
 345                         amount: Some(self.amount_msats),
 346                         features,
 347                         quantity: None,
 348                         payer_id: Some(&self.payer_id),
 349                         payer_note: self.payer_note.as_ref(),
 350                 };
 351
 352                 (payer, offer, invoice_request)
 353         }
 354 }
 355
 356 impl Writeable for Refund {
 357         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 358                 WithoutLength(&self.bytes).write(writer)
 359         }
 360 }
 361
 362 impl Writeable for RefundContents {
 363         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 364                 self.as_tlv_stream().write(writer)
 365         }
 366 }
 367
 368 type RefundTlvStream = (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream);
 369
 370 type RefundTlvStreamRef<'a> = (
 371         PayerTlvStreamRef<'a>,
 372         OfferTlvStreamRef<'a>,
 373         InvoiceRequestTlvStreamRef<'a>,
 374 );
 375
 376 impl SeekReadable for RefundTlvStream {
 377         fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
 378                 let payer = SeekReadable::read(r)?;
 379                 let offer = SeekReadable::read(r)?;
 380                 let invoice_request = SeekReadable::read(r)?;
 381
 382                 Ok((payer, offer, invoice_request))
 383         }
 384 }
 385
 386 impl Bech32Encode for Refund {
 387         const BECH32_HRP: &'static str = "lnr";
 388 }
 389
 390 impl FromStr for Refund {
 391         type Err = ParseError;
 392
 393         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 394                 Refund::from_bech32_str(s)
 395         }
 396 }
 397
 398 impl TryFrom<Vec<u8>> for Refund {
 399         type Error = ParseError;
 400
 401         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 402                 let refund = ParsedMessage::<RefundTlvStream>::try_from(bytes)?;
 403                 let ParsedMessage { bytes, tlv_stream } = refund;
 404                 let contents = RefundContents::try_from(tlv_stream)?;
 405
 406                 Ok(Refund { bytes, contents })
 407         }
 408 }
 409
 410 impl TryFrom<RefundTlvStream> for RefundContents {
 411         type Error = SemanticError;
 412
 413         fn try_from(tlv_stream: RefundTlvStream) -> Result<Self, Self::Error> {
 414                 let (
 415                         PayerTlvStream { metadata: payer_metadata },
 416                         OfferTlvStream {
 417                                 chains, metadata, currency, amount: offer_amount, description,
 418                                 features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
 419                         },
 420                         InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
 421                 ) = tlv_stream;
 422
 423                 let payer = match payer_metadata {
 424                         None => return Err(SemanticError::MissingPayerMetadata),
 425                         Some(metadata) => PayerContents(metadata),
 426                 };
 427
 428                 if chains.is_some() {
 429                         return Err(SemanticError::UnexpectedChain);
 430                 }
 431
 432                 if currency.is_some() || offer_amount.is_some() {
 433                         return Err(SemanticError::UnexpectedAmount);
 434                 }
 435
 436                 let description = match description {
 437                         None => return Err(SemanticError::MissingDescription),
 438                         Some(description) => description,
 439                 };
 440
 441                 if offer_features.is_some() {
 442                         return Err(SemanticError::UnexpectedFeatures);
 443                 }
 444
 445                 let absolute_expiry = absolute_expiry.map(Duration::from_secs);
 446
 447                 if quantity_max.is_some() {
 448                         return Err(SemanticError::UnexpectedQuantity);
 449                 }
 450
 451                 if node_id.is_some() {
 452                         return Err(SemanticError::UnexpectedSigningPubkey);
 453                 }
 454
 455                 let amount_msats = match amount {
 456                         None => return Err(SemanticError::MissingAmount),
 457                         Some(amount_msats) if amount_msats > MAX_VALUE_MSAT => {
 458                                 return Err(SemanticError::InvalidAmount);
 459                         },
 460                         Some(amount_msats) => amount_msats,
 461                 };
 462
 463                 let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
 464
 465                 // TODO: Check why this isn't in the spec.
 466                 if quantity.is_some() {
 467                         return Err(SemanticError::UnexpectedQuantity);
 468                 }
 469
 470                 let payer_id = match payer_id {
 471                         None => return Err(SemanticError::MissingPayerId),
 472                         Some(payer_id) => payer_id,
 473                 };
 474
 475                 // TODO: Should metadata be included?
 476                 Ok(RefundContents {
 477                         payer, metadata, description, absolute_expiry, issuer, paths, chain, amount_msats,
 478                         features, payer_id, payer_note,
 479                 })
 480         }
 481 }
 482
 483 impl core::fmt::Display for Refund {
 484         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 485                 self.fmt_bech32_str(f)
 486         }
 487 }
 488
 489 #[cfg(test)]
 490 mod tests {
 491         use super::{Refund, RefundBuilder, RefundTlvStreamRef};
 492
 493         use bitcoin::blockdata::constants::ChainHash;
 494         use bitcoin::network::constants::Network;
 495         use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
 496         use core::convert::TryFrom;
 497         use core::time::Duration;
 498         use crate::ln::features::{InvoiceRequestFeatures, OfferFeatures};
 499         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 500         use crate::offers::invoice_request::InvoiceRequestTlvStreamRef;
 501         use crate::offers::offer::OfferTlvStreamRef;
 502         use crate::offers::parse::{ParseError, SemanticError};
 503         use crate::offers::payer::PayerTlvStreamRef;
 504         use crate::onion_message::{BlindedHop, BlindedPath};
 505         use crate::util::ser::{BigSize, Writeable};
 506         use crate::util::string::PrintableString;
 507
 508         fn payer_pubkey() -> PublicKey {
 509                 let secp_ctx = Secp256k1::new();
 510                 KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()).public_key()
 511         }
 512
 513         fn pubkey(byte: u8) -> PublicKey {
 514                 let secp_ctx = Secp256k1::new();
 515                 PublicKey::from_secret_key(&secp_ctx, &privkey(byte))
 516         }
 517
 518         fn privkey(byte: u8) -> SecretKey {
 519                 SecretKey::from_slice(&[byte; 32]).unwrap()
 520         }
 521
 522         trait ToBytes {
 523                 fn to_bytes(&self) -> Vec<u8>;
 524         }
 525
 526         impl<'a> ToBytes for RefundTlvStreamRef<'a> {
 527                 fn to_bytes(&self) -> Vec<u8> {
 528                         let mut buffer = Vec::new();
 529                         self.write(&mut buffer).unwrap();
 530                         buffer
 531                 }
 532         }
 533
 534         #[test]
 535         fn builds_refund_with_defaults() {
 536                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 537                         .build().unwrap();
 538
 539                 let mut buffer = Vec::new();
 540                 refund.write(&mut buffer).unwrap();
 541
 542                 assert_eq!(refund.bytes, buffer.as_slice());
 543                 assert_eq!(refund.metadata(), &[1; 32]);
 544                 assert_eq!(refund.description(), PrintableString("foo"));
 545                 assert_eq!(refund.absolute_expiry(), None);
 546                 #[cfg(feature = "std")]
 547                 assert!(!refund.is_expired());
 548                 assert_eq!(refund.paths(), &[]);
 549                 assert_eq!(refund.issuer(), None);
 550                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Bitcoin));
 551                 assert_eq!(refund.amount_msats(), 1000);
 552                 assert_eq!(refund.features(), &InvoiceRequestFeatures::empty());
 553                 assert_eq!(refund.payer_id(), payer_pubkey());
 554                 assert_eq!(refund.payer_note(), None);
 555
 556                 assert_eq!(
 557                         refund.as_tlv_stream(),
 558                         (
 559                                 PayerTlvStreamRef { metadata: Some(&vec![1; 32]) },
 560                                 OfferTlvStreamRef {
 561                                         chains: None,
 562                                         metadata: None,
 563                                         currency: None,
 564                                         amount: None,
 565                                         description: Some(&String::from("foo")),
 566                                         features: None,
 567                                         absolute_expiry: None,
 568                                         paths: None,
 569                                         issuer: None,
 570                                         quantity_max: None,
 571                                         node_id: None,
 572                                 },
 573                                 InvoiceRequestTlvStreamRef {
 574                                         chain: None,
 575                                         amount: Some(1000),
 576                                         features: None,
 577                                         quantity: None,
 578                                         payer_id: Some(&payer_pubkey()),
 579                                         payer_note: None,
 580                                 },
 581                         ),
 582                 );
 583
 584                 if let Err(e) = Refund::try_from(buffer) {
 585                         panic!("error parsing refund: {:?}", e);
 586                 }
 587         }
 588
 589         #[test]
 590         fn fails_building_refund_with_invalid_amount() {
 591                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), MAX_VALUE_MSAT + 1) {
 592                         Ok(_) => panic!("expected error"),
 593                         Err(e) => assert_eq!(e, SemanticError::InvalidAmount),
 594                 }
 595         }
 596
 597         #[test]
 598         fn builds_refund_with_absolute_expiry() {
 599                 let future_expiry = Duration::from_secs(u64::max_value());
 600                 let past_expiry = Duration::from_secs(0);
 601
 602                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 603                         .absolute_expiry(future_expiry)
 604                         .build()
 605                         .unwrap();
 606                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 607                 #[cfg(feature = "std")]
 608                 assert!(!refund.is_expired());
 609                 assert_eq!(refund.absolute_expiry(), Some(future_expiry));
 610                 assert_eq!(tlv_stream.absolute_expiry, Some(future_expiry.as_secs()));
 611
 612                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 613                         .absolute_expiry(future_expiry)
 614                         .absolute_expiry(past_expiry)
 615                         .build()
 616                         .unwrap();
 617                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 618                 #[cfg(feature = "std")]
 619                 assert!(refund.is_expired());
 620                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
 621                 assert_eq!(tlv_stream.absolute_expiry, Some(past_expiry.as_secs()));
 622         }
 623
 624         #[test]
 625         fn builds_refund_with_paths() {
 626                 let paths = vec![
 627                         BlindedPath {
 628                                 introduction_node_id: pubkey(40),
 629                                 blinding_point: pubkey(41),
 630                                 blinded_hops: vec![
 631                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
 632                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
 633                                 ],
 634                         },
 635                         BlindedPath {
 636                                 introduction_node_id: pubkey(40),
 637                                 blinding_point: pubkey(41),
 638                                 blinded_hops: vec![
 639                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
 640                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
 641                                 ],
 642                         },
 643                 ];
 644
 645                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 646                         .path(paths[0].clone())
 647                         .path(paths[1].clone())
 648                         .build()
 649                         .unwrap();
 650                 let (_, offer_tlv_stream, invoice_request_tlv_stream) = refund.as_tlv_stream();
 651                 assert_eq!(refund.paths(), paths.as_slice());
 652                 assert_eq!(refund.payer_id(), pubkey(42));
 653                 assert_ne!(pubkey(42), pubkey(44));
 654                 assert_eq!(offer_tlv_stream.paths, Some(&paths));
 655                 assert_eq!(invoice_request_tlv_stream.payer_id, Some(&pubkey(42)));
 656         }
 657
 658         #[test]
 659         fn builds_refund_with_issuer() {
 660                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 661                         .issuer("bar".into())
 662                         .build()
 663                         .unwrap();
 664                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 665                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
 666                 assert_eq!(tlv_stream.issuer, Some(&String::from("bar")));
 667
 668                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 669                         .issuer("bar".into())
 670                         .issuer("baz".into())
 671                         .build()
 672                         .unwrap();
 673                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 674                 assert_eq!(refund.issuer(), Some(PrintableString("baz")));
 675                 assert_eq!(tlv_stream.issuer, Some(&String::from("baz")));
 676         }
 677
 678         #[test]
 679         fn builds_refund_with_chain() {
 680                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
 681                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
 682
 683                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 684                         .chain(Network::Bitcoin)
 685                         .build().unwrap();
 686                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 687                 assert_eq!(refund.chain(), mainnet);
 688                 assert_eq!(tlv_stream.chain, None);
 689
 690                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 691                         .chain(Network::Testnet)
 692                         .build().unwrap();
 693                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 694                 assert_eq!(refund.chain(), testnet);
 695                 assert_eq!(tlv_stream.chain, Some(&testnet));
 696
 697                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 698                         .chain(Network::Regtest)
 699                         .chain(Network::Testnet)
 700                         .build().unwrap();
 701                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 702                 assert_eq!(refund.chain(), testnet);
 703                 assert_eq!(tlv_stream.chain, Some(&testnet));
 704         }
 705
 706         #[test]
 707         fn builds_refund_with_payer_note() {
 708                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 709                         .payer_note("bar".into())
 710                         .build().unwrap();
 711                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 712                 assert_eq!(refund.payer_note(), Some(PrintableString("bar")));
 713                 assert_eq!(tlv_stream.payer_note, Some(&String::from("bar")));
 714
 715                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 716                         .payer_note("bar".into())
 717                         .payer_note("baz".into())
 718                         .build().unwrap();
 719                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 720                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
 721                 assert_eq!(tlv_stream.payer_note, Some(&String::from("baz")));
 722         }
 723
 724         #[test]
 725         fn parses_refund_with_metadata() {
 726                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 727                         .build().unwrap();
 728                 if let Err(e) = refund.to_string().parse::<Refund>() {
 729                         panic!("error parsing refund: {:?}", e);
 730                 }
 731
 732                 let mut tlv_stream = refund.as_tlv_stream();
 733                 tlv_stream.0.metadata = None;
 734
 735                 match Refund::try_from(tlv_stream.to_bytes()) {
 736                         Ok(_) => panic!("expected error"),
 737                         Err(e) => {
 738                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingPayerMetadata));
 739                         },
 740                 }
 741         }
 742
 743         #[test]
 744         fn parses_refund_with_description() {
 745                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 746                         .build().unwrap();
 747                 if let Err(e) = refund.to_string().parse::<Refund>() {
 748                         panic!("error parsing refund: {:?}", e);
 749                 }
 750
 751                 let mut tlv_stream = refund.as_tlv_stream();
 752                 tlv_stream.1.description = None;
 753
 754                 match Refund::try_from(tlv_stream.to_bytes()) {
 755                         Ok(_) => panic!("expected error"),
 756                         Err(e) => {
 757                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingDescription));
 758                         },
 759                 }
 760         }
 761
 762         #[test]
 763         fn parses_refund_with_amount() {
 764                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 765                         .build().unwrap();
 766                 if let Err(e) = refund.to_string().parse::<Refund>() {
 767                         panic!("error parsing refund: {:?}", e);
 768                 }
 769
 770                 let mut tlv_stream = refund.as_tlv_stream();
 771                 tlv_stream.2.amount = None;
 772
 773                 match Refund::try_from(tlv_stream.to_bytes()) {
 774                         Ok(_) => panic!("expected error"),
 775                         Err(e) => {
 776                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingAmount));
 777                         },
 778                 }
 779
 780                 let mut tlv_stream = refund.as_tlv_stream();
 781                 tlv_stream.2.amount = Some(MAX_VALUE_MSAT + 1);
 782
 783                 match Refund::try_from(tlv_stream.to_bytes()) {
 784                         Ok(_) => panic!("expected error"),
 785                         Err(e) => {
 786                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::InvalidAmount));
 787                         },
 788                 }
 789         }
 790
 791         #[test]
 792         fn parses_refund_with_payer_id() {
 793                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 794                         .build().unwrap();
 795                 if let Err(e) = refund.to_string().parse::<Refund>() {
 796                         panic!("error parsing refund: {:?}", e);
 797                 }
 798
 799                 let mut tlv_stream = refund.as_tlv_stream();
 800                 tlv_stream.2.payer_id = None;
 801
 802                 match Refund::try_from(tlv_stream.to_bytes()) {
 803                         Ok(_) => panic!("expected error"),
 804                         Err(e) => {
 805                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingPayerId));
 806                         },
 807                 }
 808         }
 809
 810         #[test]
 811         fn parses_refund_with_optional_fields() {
 812                 let past_expiry = Duration::from_secs(0);
 813                 let paths = vec![
 814                         BlindedPath {
 815                                 introduction_node_id: pubkey(40),
 816                                 blinding_point: pubkey(41),
 817                                 blinded_hops: vec![
 818                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
 819                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
 820                                 ],
 821                         },
 822                         BlindedPath {
 823                                 introduction_node_id: pubkey(40),
 824                                 blinding_point: pubkey(41),
 825                                 blinded_hops: vec![
 826                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
 827                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
 828                                 ],
 829                         },
 830                 ];
 831
 832                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 833                         .absolute_expiry(past_expiry)
 834                         .issuer("bar".into())
 835                         .path(paths[0].clone())
 836                         .path(paths[1].clone())
 837                         .chain(Network::Testnet)
 838                         .features_unchecked(InvoiceRequestFeatures::unknown())
 839                         .payer_note("baz".into())
 840                         .build()
 841                         .unwrap();
 842                 match refund.to_string().parse::<Refund>() {
 843                         Ok(refund) => {
 844                                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
 845                                 #[cfg(feature = "std")]
 846                                 assert!(refund.is_expired());
 847                                 assert_eq!(refund.paths(), &paths[..]);
 848                                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
 849                                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Testnet));
 850                                 assert_eq!(refund.features(), &InvoiceRequestFeatures::unknown());
 851                                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
 852                         },
 853                         Err(e) => panic!("error parsing refund: {:?}", e),
 854                 }
 855         }
 856
 857         #[test]
 858         fn fails_parsing_refund_with_unexpected_fields() {
 859                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 860                         .build().unwrap();
 861                 if let Err(e) = refund.to_string().parse::<Refund>() {
 862                         panic!("error parsing refund: {:?}", e);
 863                 }
 864
 865                 let chains = vec![ChainHash::using_genesis_block(Network::Testnet)];
 866                 let mut tlv_stream = refund.as_tlv_stream();
 867                 tlv_stream.1.chains = Some(&chains);
 868
 869                 match Refund::try_from(tlv_stream.to_bytes()) {
 870                         Ok(_) => panic!("expected error"),
 871                         Err(e) => {
 872                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedChain));
 873                         },
 874                 }
 875
 876                 let mut tlv_stream = refund.as_tlv_stream();
 877                 tlv_stream.1.currency = Some(&b"USD");
 878                 tlv_stream.1.amount = Some(1000);
 879
 880                 match Refund::try_from(tlv_stream.to_bytes()) {
 881                         Ok(_) => panic!("expected error"),
 882                         Err(e) => {
 883                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedAmount));
 884                         },
 885                 }
 886
 887                 let features = OfferFeatures::unknown();
 888                 let mut tlv_stream = refund.as_tlv_stream();
 889                 tlv_stream.1.features = Some(&features);
 890
 891                 match Refund::try_from(tlv_stream.to_bytes()) {
 892                         Ok(_) => panic!("expected error"),
 893                         Err(e) => {
 894                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedFeatures));
 895                         },
 896                 }
 897
 898                 let mut tlv_stream = refund.as_tlv_stream();
 899                 tlv_stream.1.quantity_max = Some(10);
 900
 901                 match Refund::try_from(tlv_stream.to_bytes()) {
 902                         Ok(_) => panic!("expected error"),
 903                         Err(e) => {
 904                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedQuantity));
 905                         },
 906                 }
 907
 908                 let node_id = payer_pubkey();
 909                 let mut tlv_stream = refund.as_tlv_stream();
 910                 tlv_stream.1.node_id = Some(&node_id);
 911
 912                 match Refund::try_from(tlv_stream.to_bytes()) {
 913                         Ok(_) => panic!("expected error"),
 914                         Err(e) => {
 915                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedSigningPubkey));
 916                         },
 917                 }
 918
 919                 let mut tlv_stream = refund.as_tlv_stream();
 920                 tlv_stream.2.quantity = Some(10);
 921
 922                 match Refund::try_from(tlv_stream.to_bytes()) {
 923                         Ok(_) => panic!("expected error"),
 924                         Err(e) => {
 925                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedQuantity));
 926                         },
 927                 }
 928         }
 929
 930         #[test]
 931         fn fails_parsing_refund_with_extra_tlv_records() {
 932                 let secp_ctx = Secp256k1::new();
 933                 let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
 934                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], keys.public_key(), 1000).unwrap()
 935                         .build().unwrap();
 936
 937                 let mut encoded_refund = Vec::new();
 938                 refund.write(&mut encoded_refund).unwrap();
 939                 BigSize(1002).write(&mut encoded_refund).unwrap();
 940                 BigSize(32).write(&mut encoded_refund).unwrap();
 941                 [42u8; 32].write(&mut encoded_refund).unwrap();
 942
 943                 match Refund::try_from(encoded_refund) {
 944                         Ok(_) => panic!("expected error"),
 945                         Err(e) => assert_eq!(e, ParseError::Decode(DecodeError::InvalidValue)),
 946                 }
 947         }
 948 }