_ 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(), quantity: None, 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 [`Refund::quantity`] of items. This is purely for informational purposes. It is useful
 166         /// when the refund pertains to an [`Invoice`] that paid for more than one item from an
 167         /// [`Offer`] as specified by [`InvoiceRequest::quantity`].
 168         ///
 169         /// Successive calls to this method will override the previous setting.
 170         ///
 171         /// [`Invoice`]: crate::offers::invoice::Invoice
 172         /// [`InvoiceRequest::quantity`]: crate::offers::invoice_request::InvoiceRequest::quantity
 173         /// [`Offer`]: crate::offers::offer::Offer
 174         pub fn quantity(mut self, quantity: u64) -> Self {
 175                 self.refund.quantity = Some(quantity);
 176                 self
 177         }
 178
 179         /// Sets the [`Refund::payer_note`].
 180         ///
 181         /// Successive calls to this method will override the previous setting.
 182         pub fn payer_note(mut self, payer_note: String) -> Self {
 183                 self.refund.payer_note = Some(payer_note);
 184                 self
 185         }
 186
 187         /// Builds a [`Refund`] after checking for valid semantics.
 188         pub fn build(mut self) -> Result<Refund, SemanticError> {
 189                 if self.refund.chain() == self.refund.implied_chain() {
 190                         self.refund.chain = None;
 191                 }
 192
 193                 let mut bytes = Vec::new();
 194                 self.refund.write(&mut bytes).unwrap();
 195
 196                 Ok(Refund {
 197                         bytes,
 198                         contents: self.refund,
 199                 })
 200         }
 201 }
 202
 203 #[cfg(test)]
 204 impl RefundBuilder {
 205         fn features_unchecked(mut self, features: InvoiceRequestFeatures) -> Self {
 206                 self.refund.features = features;
 207                 self
 208         }
 209 }
 210
 211 /// A `Refund` is a request to send an [`Invoice`] without a preceding [`Offer`].
 212 ///
 213 /// Typically, after an invoice is paid, the recipient may publish a refund allowing the sender to
 214 /// recoup their funds. A refund may be used more generally as an "offer for money", such as with a
 215 /// bitcoin ATM.
 216 ///
 217 /// [`Invoice`]: crate::offers::invoice::Invoice
 218 /// [`Offer`]: crate::offers::offer::Offer
 219 #[derive(Clone, Debug)]
 220 pub struct Refund {
 221         pub(super) bytes: Vec<u8>,
 222         pub(super) contents: RefundContents,
 223 }
 224
 225 /// The contents of a [`Refund`], which may be shared with an [`Invoice`].
 226 ///
 227 /// [`Invoice`]: crate::offers::invoice::Invoice
 228 #[derive(Clone, Debug)]
 229 pub(super) struct RefundContents {
 230         payer: PayerContents,
 231         // offer fields
 232         metadata: Option<Vec<u8>>,
 233         description: String,
 234         absolute_expiry: Option<Duration>,
 235         issuer: Option<String>,
 236         paths: Option<Vec<BlindedPath>>,
 237         // invoice_request fields
 238         chain: Option<ChainHash>,
 239         amount_msats: u64,
 240         features: InvoiceRequestFeatures,
 241         quantity: Option<u64>,
 242         payer_id: PublicKey,
 243         payer_note: Option<String>,
 244 }
 245
 246 impl Refund {
 247         /// A complete description of the purpose of the refund. Intended to be displayed to the user
 248         /// but with the caveat that it has not been verified in any way.
 249         pub fn description(&self) -> PrintableString {
 250                 PrintableString(&self.contents.description)
 251         }
 252
 253         /// Duration since the Unix epoch when an invoice should no longer be sent.
 254         ///
 255         /// If `None`, the refund does not expire.
 256         pub fn absolute_expiry(&self) -> Option<Duration> {
 257                 self.contents.absolute_expiry
 258         }
 259
 260         /// Whether the refund has expired.
 261         #[cfg(feature = "std")]
 262         pub fn is_expired(&self) -> bool {
 263                 self.contents.is_expired()
 264         }
 265
 266         /// The issuer of the refund, possibly beginning with `user@domain` or `domain`. Intended to be
 267         /// displayed to the user but with the caveat that it has not been verified in any way.
 268         pub fn issuer(&self) -> Option<PrintableString> {
 269                 self.contents.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 270         }
 271
 272         /// Paths to the sender originating from publicly reachable nodes. Blinded paths provide sender
 273         /// privacy by obfuscating its node id.
 274         pub fn paths(&self) -> &[BlindedPath] {
 275                 self.contents.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 276         }
 277
 278         /// An unpredictable series of bytes, typically containing information about the derivation of
 279         /// [`payer_id`].
 280         ///
 281         /// [`payer_id`]: Self::payer_id
 282         pub fn metadata(&self) -> &[u8] {
 283                 &self.contents.payer.0
 284         }
 285
 286         /// A chain that the refund is valid for.
 287         pub fn chain(&self) -> ChainHash {
 288                 self.contents.chain.unwrap_or_else(|| self.contents.implied_chain())
 289         }
 290
 291         /// The amount to refund in msats (i.e., the minimum lightning-payable unit for [`chain`]).
 292         ///
 293         /// [`chain`]: Self::chain
 294         pub fn amount_msats(&self) -> u64 {
 295                 self.contents.amount_msats
 296         }
 297
 298         /// Features pertaining to requesting an invoice.
 299         pub fn features(&self) -> &InvoiceRequestFeatures {
 300                 &self.contents.features
 301         }
 302
 303         /// The quantity of an item that refund is for.
 304         pub fn quantity(&self) -> Option<u64> {
 305                 self.contents.quantity
 306         }
 307
 308         /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
 309         /// transient pubkey.
 310         ///
 311         /// [`paths`]: Self::paths
 312         pub fn payer_id(&self) -> PublicKey {
 313                 self.contents.payer_id
 314         }
 315
 316         /// Payer provided note to include in the invoice.
 317         pub fn payer_note(&self) -> Option<PrintableString> {
 318                 self.contents.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
 319         }
 320
 321         /// Creates an [`Invoice`] for the refund with the given required fields.
 322         ///
 323         /// Unless [`InvoiceBuilder::relative_expiry`] is set, the invoice will expire two hours after
 324         /// calling this method in `std` builds. For `no-std` builds, a final [`Duration`] parameter
 325         /// must be given, which is used to set [`Invoice::created_at`] since [`std::time::SystemTime`]
 326         /// is not available.
 327         ///
 328         /// The caller is expected to remember the preimage of `payment_hash` in order to
 329         /// claim a payment for the invoice.
 330         ///
 331         /// The `signing_pubkey` is required to sign the invoice since refunds are not in response to an
 332         /// offer, which does have a `signing_pubkey`.
 333         ///
 334         /// The `payment_paths` parameter is useful for maintaining the payment recipient's privacy. It
 335         /// must contain one or more elements.
 336         ///
 337         /// Errors if the request contains unknown required features.
 338         ///
 339         /// [`Invoice`]: crate::offers::invoice::Invoice
 340         /// [`Invoice::created_at`]: crate::offers::invoice::Invoice::created_at
 341         pub fn respond_with(
 342                 &self, payment_paths: Vec<(BlindedPath, BlindedPayInfo)>, payment_hash: PaymentHash,
 343                 signing_pubkey: PublicKey,
 344                 #[cfg(any(test, not(feature = "std")))]
 345                 created_at: Duration
 346         ) -> Result<InvoiceBuilder, SemanticError> {
 347                 if self.features().requires_unknown_bits() {
 348                         return Err(SemanticError::UnknownRequiredFeatures);
 349                 }
 350
 351                 #[cfg(all(not(test), feature = "std"))]
 352                 let created_at = std::time::SystemTime::now()
 353                         .duration_since(std::time::SystemTime::UNIX_EPOCH)
 354                         .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 355
 356                 InvoiceBuilder::for_refund(self, payment_paths, created_at, payment_hash, signing_pubkey)
 357         }
 358
 359         #[cfg(test)]
 360         fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 361                 self.contents.as_tlv_stream()
 362         }
 363 }
 364
 365 impl AsRef<[u8]> for Refund {
 366         fn as_ref(&self) -> &[u8] {
 367                 &self.bytes
 368         }
 369 }
 370
 371 impl RefundContents {
 372         #[cfg(feature = "std")]
 373         pub(super) fn is_expired(&self) -> bool {
 374                 match self.absolute_expiry {
 375                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
 376                                 Ok(elapsed) => elapsed > seconds_from_epoch,
 377                                 Err(_) => false,
 378                         },
 379                         None => false,
 380                 }
 381         }
 382
 383         pub(super) fn chain(&self) -> ChainHash {
 384                 self.chain.unwrap_or_else(|| self.implied_chain())
 385         }
 386
 387         pub fn implied_chain(&self) -> ChainHash {
 388                 ChainHash::using_genesis_block(Network::Bitcoin)
 389         }
 390
 391         pub(super) fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 392                 let payer = PayerTlvStreamRef {
 393                         metadata: Some(&self.payer.0),
 394                 };
 395
 396                 let offer = OfferTlvStreamRef {
 397                         chains: None,
 398                         metadata: self.metadata.as_ref(),
 399                         currency: None,
 400                         amount: None,
 401                         description: Some(&self.description),
 402                         features: None,
 403                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 404                         paths: self.paths.as_ref(),
 405                         issuer: self.issuer.as_ref(),
 406                         quantity_max: None,
 407                         node_id: None,
 408                 };
 409
 410                 let features = {
 411                         if self.features == InvoiceRequestFeatures::empty() { None }
 412                         else { Some(&self.features) }
 413                 };
 414
 415                 let invoice_request = InvoiceRequestTlvStreamRef {
 416                         chain: self.chain.as_ref(),
 417                         amount: Some(self.amount_msats),
 418                         features,
 419                         quantity: self.quantity,
 420                         payer_id: Some(&self.payer_id),
 421                         payer_note: self.payer_note.as_ref(),
 422                 };
 423
 424                 (payer, offer, invoice_request)
 425         }
 426 }
 427
 428 impl Writeable for Refund {
 429         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 430                 WithoutLength(&self.bytes).write(writer)
 431         }
 432 }
 433
 434 impl Writeable for RefundContents {
 435         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 436                 self.as_tlv_stream().write(writer)
 437         }
 438 }
 439
 440 type RefundTlvStream = (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream);
 441
 442 type RefundTlvStreamRef<'a> = (
 443         PayerTlvStreamRef<'a>,
 444         OfferTlvStreamRef<'a>,
 445         InvoiceRequestTlvStreamRef<'a>,
 446 );
 447
 448 impl SeekReadable for RefundTlvStream {
 449         fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
 450                 let payer = SeekReadable::read(r)?;
 451                 let offer = SeekReadable::read(r)?;
 452                 let invoice_request = SeekReadable::read(r)?;
 453
 454                 Ok((payer, offer, invoice_request))
 455         }
 456 }
 457
 458 impl Bech32Encode for Refund {
 459         const BECH32_HRP: &'static str = "lnr";
 460 }
 461
 462 impl FromStr for Refund {
 463         type Err = ParseError;
 464
 465         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 466                 Refund::from_bech32_str(s)
 467         }
 468 }
 469
 470 impl TryFrom<Vec<u8>> for Refund {
 471         type Error = ParseError;
 472
 473         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 474                 let refund = ParsedMessage::<RefundTlvStream>::try_from(bytes)?;
 475                 let ParsedMessage { bytes, tlv_stream } = refund;
 476                 let contents = RefundContents::try_from(tlv_stream)?;
 477
 478                 Ok(Refund { bytes, contents })
 479         }
 480 }
 481
 482 impl TryFrom<RefundTlvStream> for RefundContents {
 483         type Error = SemanticError;
 484
 485         fn try_from(tlv_stream: RefundTlvStream) -> Result<Self, Self::Error> {
 486                 let (
 487                         PayerTlvStream { metadata: payer_metadata },
 488                         OfferTlvStream {
 489                                 chains, metadata, currency, amount: offer_amount, description,
 490                                 features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
 491                         },
 492                         InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
 493                 ) = tlv_stream;
 494
 495                 let payer = match payer_metadata {
 496                         None => return Err(SemanticError::MissingPayerMetadata),
 497                         Some(metadata) => PayerContents(metadata),
 498                 };
 499
 500                 if chains.is_some() {
 501                         return Err(SemanticError::UnexpectedChain);
 502                 }
 503
 504                 if currency.is_some() || offer_amount.is_some() {
 505                         return Err(SemanticError::UnexpectedAmount);
 506                 }
 507
 508                 let description = match description {
 509                         None => return Err(SemanticError::MissingDescription),
 510                         Some(description) => description,
 511                 };
 512
 513                 if offer_features.is_some() {
 514                         return Err(SemanticError::UnexpectedFeatures);
 515                 }
 516
 517                 let absolute_expiry = absolute_expiry.map(Duration::from_secs);
 518
 519                 if quantity_max.is_some() {
 520                         return Err(SemanticError::UnexpectedQuantity);
 521                 }
 522
 523                 if node_id.is_some() {
 524                         return Err(SemanticError::UnexpectedSigningPubkey);
 525                 }
 526
 527                 let amount_msats = match amount {
 528                         None => return Err(SemanticError::MissingAmount),
 529                         Some(amount_msats) if amount_msats > MAX_VALUE_MSAT => {
 530                                 return Err(SemanticError::InvalidAmount);
 531                         },
 532                         Some(amount_msats) => amount_msats,
 533                 };
 534
 535                 let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
 536
 537                 let payer_id = match payer_id {
 538                         None => return Err(SemanticError::MissingPayerId),
 539                         Some(payer_id) => payer_id,
 540                 };
 541
 542                 // TODO: Should metadata be included?
 543                 Ok(RefundContents {
 544                         payer, metadata, description, absolute_expiry, issuer, paths, chain, amount_msats,
 545                         features, quantity, payer_id, payer_note,
 546                 })
 547         }
 548 }
 549
 550 impl core::fmt::Display for Refund {
 551         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 552                 self.fmt_bech32_str(f)
 553         }
 554 }
 555
 556 #[cfg(test)]
 557 mod tests {
 558         use super::{Refund, RefundBuilder, RefundTlvStreamRef};
 559
 560         use bitcoin::blockdata::constants::ChainHash;
 561         use bitcoin::network::constants::Network;
 562         use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
 563         use core::convert::TryFrom;
 564         use core::time::Duration;
 565         use crate::ln::features::{InvoiceRequestFeatures, OfferFeatures};
 566         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 567         use crate::offers::invoice_request::InvoiceRequestTlvStreamRef;
 568         use crate::offers::offer::OfferTlvStreamRef;
 569         use crate::offers::parse::{ParseError, SemanticError};
 570         use crate::offers::payer::PayerTlvStreamRef;
 571         use crate::onion_message::{BlindedHop, BlindedPath};
 572         use crate::util::ser::{BigSize, Writeable};
 573         use crate::util::string::PrintableString;
 574
 575         fn payer_pubkey() -> PublicKey {
 576                 let secp_ctx = Secp256k1::new();
 577                 KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()).public_key()
 578         }
 579
 580         fn pubkey(byte: u8) -> PublicKey {
 581                 let secp_ctx = Secp256k1::new();
 582                 PublicKey::from_secret_key(&secp_ctx, &privkey(byte))
 583         }
 584
 585         fn privkey(byte: u8) -> SecretKey {
 586                 SecretKey::from_slice(&[byte; 32]).unwrap()
 587         }
 588
 589         trait ToBytes {
 590                 fn to_bytes(&self) -> Vec<u8>;
 591         }
 592
 593         impl<'a> ToBytes for RefundTlvStreamRef<'a> {
 594                 fn to_bytes(&self) -> Vec<u8> {
 595                         let mut buffer = Vec::new();
 596                         self.write(&mut buffer).unwrap();
 597                         buffer
 598                 }
 599         }
 600
 601         #[test]
 602         fn builds_refund_with_defaults() {
 603                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 604                         .build().unwrap();
 605
 606                 let mut buffer = Vec::new();
 607                 refund.write(&mut buffer).unwrap();
 608
 609                 assert_eq!(refund.bytes, buffer.as_slice());
 610                 assert_eq!(refund.metadata(), &[1; 32]);
 611                 assert_eq!(refund.description(), PrintableString("foo"));
 612                 assert_eq!(refund.absolute_expiry(), None);
 613                 #[cfg(feature = "std")]
 614                 assert!(!refund.is_expired());
 615                 assert_eq!(refund.paths(), &[]);
 616                 assert_eq!(refund.issuer(), None);
 617                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Bitcoin));
 618                 assert_eq!(refund.amount_msats(), 1000);
 619                 assert_eq!(refund.features(), &InvoiceRequestFeatures::empty());
 620                 assert_eq!(refund.payer_id(), payer_pubkey());
 621                 assert_eq!(refund.payer_note(), None);
 622
 623                 assert_eq!(
 624                         refund.as_tlv_stream(),
 625                         (
 626                                 PayerTlvStreamRef { metadata: Some(&vec![1; 32]) },
 627                                 OfferTlvStreamRef {
 628                                         chains: None,
 629                                         metadata: None,
 630                                         currency: None,
 631                                         amount: None,
 632                                         description: Some(&String::from("foo")),
 633                                         features: None,
 634                                         absolute_expiry: None,
 635                                         paths: None,
 636                                         issuer: None,
 637                                         quantity_max: None,
 638                                         node_id: None,
 639                                 },
 640                                 InvoiceRequestTlvStreamRef {
 641                                         chain: None,
 642                                         amount: Some(1000),
 643                                         features: None,
 644                                         quantity: None,
 645                                         payer_id: Some(&payer_pubkey()),
 646                                         payer_note: None,
 647                                 },
 648                         ),
 649                 );
 650
 651                 if let Err(e) = Refund::try_from(buffer) {
 652                         panic!("error parsing refund: {:?}", e);
 653                 }
 654         }
 655
 656         #[test]
 657         fn fails_building_refund_with_invalid_amount() {
 658                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), MAX_VALUE_MSAT + 1) {
 659                         Ok(_) => panic!("expected error"),
 660                         Err(e) => assert_eq!(e, SemanticError::InvalidAmount),
 661                 }
 662         }
 663
 664         #[test]
 665         fn builds_refund_with_absolute_expiry() {
 666                 let future_expiry = Duration::from_secs(u64::max_value());
 667                 let past_expiry = Duration::from_secs(0);
 668
 669                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 670                         .absolute_expiry(future_expiry)
 671                         .build()
 672                         .unwrap();
 673                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 674                 #[cfg(feature = "std")]
 675                 assert!(!refund.is_expired());
 676                 assert_eq!(refund.absolute_expiry(), Some(future_expiry));
 677                 assert_eq!(tlv_stream.absolute_expiry, Some(future_expiry.as_secs()));
 678
 679                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 680                         .absolute_expiry(future_expiry)
 681                         .absolute_expiry(past_expiry)
 682                         .build()
 683                         .unwrap();
 684                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 685                 #[cfg(feature = "std")]
 686                 assert!(refund.is_expired());
 687                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
 688                 assert_eq!(tlv_stream.absolute_expiry, Some(past_expiry.as_secs()));
 689         }
 690
 691         #[test]
 692         fn builds_refund_with_paths() {
 693                 let paths = vec![
 694                         BlindedPath {
 695                                 introduction_node_id: pubkey(40),
 696                                 blinding_point: pubkey(41),
 697                                 blinded_hops: vec![
 698                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
 699                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
 700                                 ],
 701                         },
 702                         BlindedPath {
 703                                 introduction_node_id: pubkey(40),
 704                                 blinding_point: pubkey(41),
 705                                 blinded_hops: vec![
 706                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
 707                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
 708                                 ],
 709                         },
 710                 ];
 711
 712                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 713                         .path(paths[0].clone())
 714                         .path(paths[1].clone())
 715                         .build()
 716                         .unwrap();
 717                 let (_, offer_tlv_stream, invoice_request_tlv_stream) = refund.as_tlv_stream();
 718                 assert_eq!(refund.paths(), paths.as_slice());
 719                 assert_eq!(refund.payer_id(), pubkey(42));
 720                 assert_ne!(pubkey(42), pubkey(44));
 721                 assert_eq!(offer_tlv_stream.paths, Some(&paths));
 722                 assert_eq!(invoice_request_tlv_stream.payer_id, Some(&pubkey(42)));
 723         }
 724
 725         #[test]
 726         fn builds_refund_with_issuer() {
 727                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 728                         .issuer("bar".into())
 729                         .build()
 730                         .unwrap();
 731                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 732                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
 733                 assert_eq!(tlv_stream.issuer, Some(&String::from("bar")));
 734
 735                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 736                         .issuer("bar".into())
 737                         .issuer("baz".into())
 738                         .build()
 739                         .unwrap();
 740                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 741                 assert_eq!(refund.issuer(), Some(PrintableString("baz")));
 742                 assert_eq!(tlv_stream.issuer, Some(&String::from("baz")));
 743         }
 744
 745         #[test]
 746         fn builds_refund_with_chain() {
 747                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
 748                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
 749
 750                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 751                         .chain(Network::Bitcoin)
 752                         .build().unwrap();
 753                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 754                 assert_eq!(refund.chain(), mainnet);
 755                 assert_eq!(tlv_stream.chain, None);
 756
 757                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 758                         .chain(Network::Testnet)
 759                         .build().unwrap();
 760                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 761                 assert_eq!(refund.chain(), testnet);
 762                 assert_eq!(tlv_stream.chain, Some(&testnet));
 763
 764                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 765                         .chain(Network::Regtest)
 766                         .chain(Network::Testnet)
 767                         .build().unwrap();
 768                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 769                 assert_eq!(refund.chain(), testnet);
 770                 assert_eq!(tlv_stream.chain, Some(&testnet));
 771         }
 772
 773         #[test]
 774         fn builds_refund_with_quantity() {
 775                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 776                         .quantity(10)
 777                         .build().unwrap();
 778                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 779                 assert_eq!(refund.quantity(), Some(10));
 780                 assert_eq!(tlv_stream.quantity, Some(10));
 781
 782                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 783                         .quantity(10)
 784                         .quantity(1)
 785                         .build().unwrap();
 786                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 787                 assert_eq!(refund.quantity(), Some(1));
 788                 assert_eq!(tlv_stream.quantity, Some(1));
 789         }
 790
 791         #[test]
 792         fn builds_refund_with_payer_note() {
 793                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 794                         .payer_note("bar".into())
 795                         .build().unwrap();
 796                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 797                 assert_eq!(refund.payer_note(), Some(PrintableString("bar")));
 798                 assert_eq!(tlv_stream.payer_note, Some(&String::from("bar")));
 799
 800                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 801                         .payer_note("bar".into())
 802                         .payer_note("baz".into())
 803                         .build().unwrap();
 804                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 805                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
 806                 assert_eq!(tlv_stream.payer_note, Some(&String::from("baz")));
 807         }
 808
 809         #[test]
 810         fn parses_refund_with_metadata() {
 811                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 812                         .build().unwrap();
 813                 if let Err(e) = refund.to_string().parse::<Refund>() {
 814                         panic!("error parsing refund: {:?}", e);
 815                 }
 816
 817                 let mut tlv_stream = refund.as_tlv_stream();
 818                 tlv_stream.0.metadata = None;
 819
 820                 match Refund::try_from(tlv_stream.to_bytes()) {
 821                         Ok(_) => panic!("expected error"),
 822                         Err(e) => {
 823                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingPayerMetadata));
 824                         },
 825                 }
 826         }
 827
 828         #[test]
 829         fn parses_refund_with_description() {
 830                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 831                         .build().unwrap();
 832                 if let Err(e) = refund.to_string().parse::<Refund>() {
 833                         panic!("error parsing refund: {:?}", e);
 834                 }
 835
 836                 let mut tlv_stream = refund.as_tlv_stream();
 837                 tlv_stream.1.description = None;
 838
 839                 match Refund::try_from(tlv_stream.to_bytes()) {
 840                         Ok(_) => panic!("expected error"),
 841                         Err(e) => {
 842                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingDescription));
 843                         },
 844                 }
 845         }
 846
 847         #[test]
 848         fn parses_refund_with_amount() {
 849                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 850                         .build().unwrap();
 851                 if let Err(e) = refund.to_string().parse::<Refund>() {
 852                         panic!("error parsing refund: {:?}", e);
 853                 }
 854
 855                 let mut tlv_stream = refund.as_tlv_stream();
 856                 tlv_stream.2.amount = None;
 857
 858                 match Refund::try_from(tlv_stream.to_bytes()) {
 859                         Ok(_) => panic!("expected error"),
 860                         Err(e) => {
 861                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingAmount));
 862                         },
 863                 }
 864
 865                 let mut tlv_stream = refund.as_tlv_stream();
 866                 tlv_stream.2.amount = Some(MAX_VALUE_MSAT + 1);
 867
 868                 match Refund::try_from(tlv_stream.to_bytes()) {
 869                         Ok(_) => panic!("expected error"),
 870                         Err(e) => {
 871                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::InvalidAmount));
 872                         },
 873                 }
 874         }
 875
 876         #[test]
 877         fn parses_refund_with_payer_id() {
 878                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 879                         .build().unwrap();
 880                 if let Err(e) = refund.to_string().parse::<Refund>() {
 881                         panic!("error parsing refund: {:?}", e);
 882                 }
 883
 884                 let mut tlv_stream = refund.as_tlv_stream();
 885                 tlv_stream.2.payer_id = None;
 886
 887                 match Refund::try_from(tlv_stream.to_bytes()) {
 888                         Ok(_) => panic!("expected error"),
 889                         Err(e) => {
 890                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingPayerId));
 891                         },
 892                 }
 893         }
 894
 895         #[test]
 896         fn parses_refund_with_optional_fields() {
 897                 let past_expiry = Duration::from_secs(0);
 898                 let paths = vec![
 899                         BlindedPath {
 900                                 introduction_node_id: pubkey(40),
 901                                 blinding_point: pubkey(41),
 902                                 blinded_hops: vec![
 903                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
 904                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
 905                                 ],
 906                         },
 907                         BlindedPath {
 908                                 introduction_node_id: pubkey(40),
 909                                 blinding_point: pubkey(41),
 910                                 blinded_hops: vec![
 911                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
 912                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
 913                                 ],
 914                         },
 915                 ];
 916
 917                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 918                         .absolute_expiry(past_expiry)
 919                         .issuer("bar".into())
 920                         .path(paths[0].clone())
 921                         .path(paths[1].clone())
 922                         .chain(Network::Testnet)
 923                         .features_unchecked(InvoiceRequestFeatures::unknown())
 924                         .quantity(10)
 925                         .payer_note("baz".into())
 926                         .build()
 927                         .unwrap();
 928                 match refund.to_string().parse::<Refund>() {
 929                         Ok(refund) => {
 930                                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
 931                                 #[cfg(feature = "std")]
 932                                 assert!(refund.is_expired());
 933                                 assert_eq!(refund.paths(), &paths[..]);
 934                                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
 935                                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Testnet));
 936                                 assert_eq!(refund.features(), &InvoiceRequestFeatures::unknown());
 937                                 assert_eq!(refund.quantity(), Some(10));
 938                                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
 939                         },
 940                         Err(e) => panic!("error parsing refund: {:?}", e),
 941                 }
 942         }
 943
 944         #[test]
 945         fn fails_parsing_refund_with_unexpected_fields() {
 946                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 947                         .build().unwrap();
 948                 if let Err(e) = refund.to_string().parse::<Refund>() {
 949                         panic!("error parsing refund: {:?}", e);
 950                 }
 951
 952                 let chains = vec![ChainHash::using_genesis_block(Network::Testnet)];
 953                 let mut tlv_stream = refund.as_tlv_stream();
 954                 tlv_stream.1.chains = Some(&chains);
 955
 956                 match Refund::try_from(tlv_stream.to_bytes()) {
 957                         Ok(_) => panic!("expected error"),
 958                         Err(e) => {
 959                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedChain));
 960                         },
 961                 }
 962
 963                 let mut tlv_stream = refund.as_tlv_stream();
 964                 tlv_stream.1.currency = Some(&b"USD");
 965                 tlv_stream.1.amount = Some(1000);
 966
 967                 match Refund::try_from(tlv_stream.to_bytes()) {
 968                         Ok(_) => panic!("expected error"),
 969                         Err(e) => {
 970                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedAmount));
 971                         },
 972                 }
 973
 974                 let features = OfferFeatures::unknown();
 975                 let mut tlv_stream = refund.as_tlv_stream();
 976                 tlv_stream.1.features = Some(&features);
 977
 978                 match Refund::try_from(tlv_stream.to_bytes()) {
 979                         Ok(_) => panic!("expected error"),
 980                         Err(e) => {
 981                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedFeatures));
 982                         },
 983                 }
 984
 985                 let mut tlv_stream = refund.as_tlv_stream();
 986                 tlv_stream.1.quantity_max = Some(10);
 987
 988                 match Refund::try_from(tlv_stream.to_bytes()) {
 989                         Ok(_) => panic!("expected error"),
 990                         Err(e) => {
 991                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedQuantity));
 992                         },
 993                 }
 994
 995                 let node_id = payer_pubkey();
 996                 let mut tlv_stream = refund.as_tlv_stream();
 997                 tlv_stream.1.node_id = Some(&node_id);
 998
 999                 match Refund::try_from(tlv_stream.to_bytes()) {
1000                         Ok(_) => panic!("expected error"),
1001                         Err(e) => {
1002                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedSigningPubkey));
1003                         },
1004                 }
1005         }
1006
1007         #[test]
1008         fn fails_parsing_refund_with_extra_tlv_records() {
1009                 let secp_ctx = Secp256k1::new();
1010                 let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
1011                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], keys.public_key(), 1000).unwrap()
1012                         .build().unwrap();
1013
1014                 let mut encoded_refund = Vec::new();
1015                 refund.write(&mut encoded_refund).unwrap();
1016                 BigSize(1002).write(&mut encoded_refund).unwrap();
1017                 BigSize(32).write(&mut encoded_refund).unwrap();
1018                 [42u8; 32].write(&mut encoded_refund).unwrap();
1019
1020                 match Refund::try_from(encoded_refund) {
1021                         Ok(_) => panic!("expected error"),
1022                         Err(e) => assert_eq!(e, ParseError::Decode(DecodeError::InvalidValue)),
1023                 }
1024         }
1025 }