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