_ Git - rust-lightning/blob - lightning/src/offers/offer.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 `offer` messages.
  11 //!
  12 //! An [`Offer`] represents an "offer to be paid." It is typically constructed by a merchant and
  13 //! published as a QR code to be scanned by a customer. The customer uses the offer to request an
  14 //! invoice from the merchant to be paid.
  15 //!
  16 //! ```
  17 //! extern crate bitcoin;
  18 //! extern crate core;
  19 //! extern crate lightning;
  20 //!
  21 //! use core::convert::TryFrom;
  22 //! use core::num::NonZeroU64;
  23 //! use core::time::Duration;
  24 //!
  25 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
  26 //! use lightning::offers::offer::{Offer, OfferBuilder, Quantity};
  27 //! use lightning::offers::parse::Bolt12ParseError;
  28 //! use lightning::util::ser::{Readable, Writeable};
  29 //!
  30 //! # use lightning::blinded_path::BlindedPath;
  31 //! # #[cfg(feature = "std")]
  32 //! # use std::time::SystemTime;
  33 //! #
  34 //! # fn create_blinded_path() -> BlindedPath { unimplemented!() }
  35 //! # fn create_another_blinded_path() -> BlindedPath { unimplemented!() }
  36 //! #
  37 //! # #[cfg(feature = "std")]
  38 //! # fn build() -> Result<(), Bolt12ParseError> {
  39 //! let secp_ctx = Secp256k1::new();
  40 //! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
  41 //! let pubkey = PublicKey::from(keys);
  42 //!
  43 //! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
  44 //! let offer = OfferBuilder::new("coffee, large".to_string(), pubkey)
  45 //!     .amount_msats(20_000)
  46 //!     .supported_quantity(Quantity::Unbounded)
  47 //!     .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
  48 //!     .issuer("Foo Bar".to_string())
  49 //!     .path(create_blinded_path())
  50 //!     .path(create_another_blinded_path())
  51 //!     .build()?;
  52 //!
  53 //! // Encode as a bech32 string for use in a QR code.
  54 //! let encoded_offer = offer.to_string();
  55 //!
  56 //! // Parse from a bech32 string after scanning from a QR code.
  57 //! let offer = encoded_offer.parse::<Offer>()?;
  58 //!
  59 //! // Encode offer as raw bytes.
  60 //! let mut bytes = Vec::new();
  61 //! offer.write(&mut bytes).unwrap();
  62 //!
  63 //! // Decode raw bytes into an offer.
  64 //! let offer = Offer::try_from(bytes)?;
  65 //! # Ok(())
  66 //! # }
  67 //! ```
  68
  69 use bitcoin::blockdata::constants::ChainHash;
  70 use bitcoin::network::constants::Network;
  71 use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, self};
  72 use core::convert::TryFrom;
  73 use core::num::NonZeroU64;
  74 use core::ops::Deref;
  75 use core::str::FromStr;
  76 use core::time::Duration;
  77 use crate::sign::EntropySource;
  78 use crate::io;
  79 use crate::blinded_path::BlindedPath;
  80 use crate::ln::channelmanager::PaymentId;
  81 use crate::ln::features::OfferFeatures;
  82 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
  83 use crate::ln::msgs::MAX_VALUE_MSAT;
  84 use crate::offers::invoice_request::{DerivedPayerId, ExplicitPayerId, InvoiceRequestBuilder};
  85 use crate::offers::merkle::TlvStream;
  86 use crate::offers::parse::{Bech32Encode, Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
  87 use crate::offers::signer::{Metadata, MetadataMaterial, self};
  88 use crate::util::ser::{HighZeroBytesDroppedBigSize, 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 pub(super) const IV_BYTES: &[u8; IV_LEN] = b"LDK Offer ~~~~~~";
  97
  98 /// Builds an [`Offer`] for the "offer to be paid" flow.
  99 ///
 100 /// See [module-level documentation] for usage.
 101 ///
 102 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 103 ///
 104 /// [module-level documentation]: self
 105 pub struct OfferBuilder<'a, M: MetadataStrategy, T: secp256k1::Signing> {
 106         offer: OfferContents,
 107         metadata_strategy: core::marker::PhantomData<M>,
 108         secp_ctx: Option<&'a Secp256k1<T>>,
 109 }
 110
 111 /// Indicates how [`Offer::metadata`] may be set.
 112 ///
 113 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 114 pub trait MetadataStrategy {}
 115
 116 /// [`Offer::metadata`] may be explicitly set or left empty.
 117 ///
 118 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 119 pub struct ExplicitMetadata {}
 120
 121 /// [`Offer::metadata`] will be derived.
 122 ///
 123 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 124 pub struct DerivedMetadata {}
 125
 126 impl MetadataStrategy for ExplicitMetadata {}
 127 impl MetadataStrategy for DerivedMetadata {}
 128
 129 impl<'a> OfferBuilder<'a, ExplicitMetadata, secp256k1::SignOnly> {
 130         /// Creates a new builder for an offer setting the [`Offer::description`] and using the
 131         /// [`Offer::signing_pubkey`] for signing invoices. The associated secret key must be remembered
 132         /// while the offer is valid.
 133         ///
 134         /// Use a different pubkey per offer to avoid correlating offers.
 135         pub fn new(description: String, signing_pubkey: PublicKey) -> Self {
 136                 OfferBuilder {
 137                         offer: OfferContents {
 138                                 chains: None, metadata: None, amount: None, description,
 139                                 features: OfferFeatures::empty(), absolute_expiry: None, issuer: None, paths: None,
 140                                 supported_quantity: Quantity::One, signing_pubkey,
 141                         },
 142                         metadata_strategy: core::marker::PhantomData,
 143                         secp_ctx: None,
 144                 }
 145         }
 146
 147         /// Sets the [`Offer::metadata`] to the given bytes.
 148         ///
 149         /// Successive calls to this method will override the previous setting.
 150         pub fn metadata(mut self, metadata: Vec<u8>) -> Result<Self, Bolt12SemanticError> {
 151                 self.offer.metadata = Some(Metadata::Bytes(metadata));
 152                 Ok(self)
 153         }
 154 }
 155
 156 impl<'a, T: secp256k1::Signing> OfferBuilder<'a, DerivedMetadata, T> {
 157         /// Similar to [`OfferBuilder::new`] except, if [`OfferBuilder::path`] is called, the signing
 158         /// pubkey is derived from the given [`ExpandedKey`] and [`EntropySource`]. This provides
 159         /// recipient privacy by using a different signing pubkey for each offer. Otherwise, the
 160         /// provided `node_id` is used for the signing pubkey.
 161         ///
 162         /// Also, sets the metadata when [`OfferBuilder::build`] is called such that it can be used by
 163         /// [`InvoiceRequest::verify`] to determine if the request was produced for the offer given an
 164         /// [`ExpandedKey`].
 165         ///
 166         /// [`InvoiceRequest::verify`]: crate::offers::invoice_request::InvoiceRequest::verify
 167         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 168         pub fn deriving_signing_pubkey<ES: Deref>(
 169                 description: String, node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 170                 secp_ctx: &'a Secp256k1<T>
 171         ) -> Self where ES::Target: EntropySource {
 172                 let nonce = Nonce::from_entropy_source(entropy_source);
 173                 let derivation_material = MetadataMaterial::new(nonce, expanded_key, IV_BYTES, None);
 174                 let metadata = Metadata::DerivedSigningPubkey(derivation_material);
 175                 OfferBuilder {
 176                         offer: OfferContents {
 177                                 chains: None, metadata: Some(metadata), amount: None, description,
 178                                 features: OfferFeatures::empty(), absolute_expiry: None, issuer: None, paths: None,
 179                                 supported_quantity: Quantity::One, signing_pubkey: node_id,
 180                         },
 181                         metadata_strategy: core::marker::PhantomData,
 182                         secp_ctx: Some(secp_ctx),
 183                 }
 184         }
 185 }
 186
 187 impl<'a, M: MetadataStrategy, T: secp256k1::Signing> OfferBuilder<'a, M, T> {
 188         /// Adds the chain hash of the given [`Network`] to [`Offer::chains`]. If not called,
 189         /// the chain hash of [`Network::Bitcoin`] is assumed to be the only one supported.
 190         ///
 191         /// See [`Offer::chains`] on how this relates to the payment currency.
 192         ///
 193         /// Successive calls to this method will add another chain hash.
 194         pub fn chain(mut self, network: Network) -> Self {
 195                 let chains = self.offer.chains.get_or_insert_with(Vec::new);
 196                 let chain = ChainHash::using_genesis_block(network);
 197                 if !chains.contains(&chain) {
 198                         chains.push(chain);
 199                 }
 200
 201                 self
 202         }
 203
 204         /// Sets the [`Offer::amount`] as an [`Amount::Bitcoin`].
 205         ///
 206         /// Successive calls to this method will override the previous setting.
 207         pub fn amount_msats(self, amount_msats: u64) -> Self {
 208                 self.amount(Amount::Bitcoin { amount_msats })
 209         }
 210
 211         /// Sets the [`Offer::amount`].
 212         ///
 213         /// Successive calls to this method will override the previous setting.
 214         pub(super) fn amount(mut self, amount: Amount) -> Self {
 215                 self.offer.amount = Some(amount);
 216                 self
 217         }
 218
 219         /// Sets the [`Offer::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
 220         /// already passed is valid and can be checked for using [`Offer::is_expired`].
 221         ///
 222         /// Successive calls to this method will override the previous setting.
 223         pub fn absolute_expiry(mut self, absolute_expiry: Duration) -> Self {
 224                 self.offer.absolute_expiry = Some(absolute_expiry);
 225                 self
 226         }
 227
 228         /// Sets the [`Offer::issuer`].
 229         ///
 230         /// Successive calls to this method will override the previous setting.
 231         pub fn issuer(mut self, issuer: String) -> Self {
 232                 self.offer.issuer = Some(issuer);
 233                 self
 234         }
 235
 236         /// Adds a blinded path to [`Offer::paths`]. Must include at least one path if only connected by
 237         /// private channels or if [`Offer::signing_pubkey`] is not a public node id.
 238         ///
 239         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 240         /// adding duplicate paths.
 241         pub fn path(mut self, path: BlindedPath) -> Self {
 242                 self.offer.paths.get_or_insert_with(Vec::new).push(path);
 243                 self
 244         }
 245
 246         /// Sets the quantity of items for [`Offer::supported_quantity`]. If not called, defaults to
 247         /// [`Quantity::One`].
 248         ///
 249         /// Successive calls to this method will override the previous setting.
 250         pub fn supported_quantity(mut self, quantity: Quantity) -> Self {
 251                 self.offer.supported_quantity = quantity;
 252                 self
 253         }
 254
 255         /// Builds an [`Offer`] from the builder's settings.
 256         pub fn build(mut self) -> Result<Offer, Bolt12SemanticError> {
 257                 match self.offer.amount {
 258                         Some(Amount::Bitcoin { amount_msats }) => {
 259                                 if amount_msats > MAX_VALUE_MSAT {
 260                                         return Err(Bolt12SemanticError::InvalidAmount);
 261                                 }
 262                         },
 263                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 264                         None => {},
 265                 }
 266
 267                 if let Some(chains) = &self.offer.chains {
 268                         if chains.len() == 1 && chains[0] == self.offer.implied_chain() {
 269                                 self.offer.chains = None;
 270                         }
 271                 }
 272
 273                 Ok(self.build_without_checks())
 274         }
 275
 276         fn build_without_checks(mut self) -> Offer {
 277                 // Create the metadata for stateless verification of an InvoiceRequest.
 278                 if let Some(mut metadata) = self.offer.metadata.take() {
 279                         if metadata.has_derivation_material() {
 280                                 if self.offer.paths.is_none() {
 281                                         metadata = metadata.without_keys();
 282                                 }
 283
 284                                 let mut tlv_stream = self.offer.as_tlv_stream();
 285                                 debug_assert_eq!(tlv_stream.metadata, None);
 286                                 tlv_stream.metadata = None;
 287                                 if metadata.derives_recipient_keys() {
 288                                         tlv_stream.node_id = None;
 289                                 }
 290
 291                                 let (derived_metadata, keys) = metadata.derive_from(tlv_stream, self.secp_ctx);
 292                                 metadata = derived_metadata;
 293                                 if let Some(keys) = keys {
 294                                         self.offer.signing_pubkey = keys.public_key();
 295                                 }
 296                         }
 297
 298                         self.offer.metadata = Some(metadata);
 299                 }
 300
 301                 let mut bytes = Vec::new();
 302                 self.offer.write(&mut bytes).unwrap();
 303
 304                 Offer { bytes, contents: self.offer }
 305         }
 306 }
 307
 308 #[cfg(test)]
 309 impl<'a, M: MetadataStrategy, T: secp256k1::Signing> OfferBuilder<'a, M, T> {
 310         fn features_unchecked(mut self, features: OfferFeatures) -> Self {
 311                 self.offer.features = features;
 312                 self
 313         }
 314
 315         pub(super) fn build_unchecked(self) -> Offer {
 316                 self.build_without_checks()
 317         }
 318 }
 319
 320 /// An `Offer` is a potentially long-lived proposal for payment of a good or service.
 321 ///
 322 /// An offer is a precursor to an [`InvoiceRequest`]. A merchant publishes an offer from which a
 323 /// customer may request an [`Bolt12Invoice`] for a specific quantity and using an amount sufficient
 324 /// to cover that quantity (i.e., at least `quantity * amount`). See [`Offer::amount`].
 325 ///
 326 /// Offers may be denominated in currency other than bitcoin but are ultimately paid using the
 327 /// latter.
 328 ///
 329 /// Through the use of [`BlindedPath`]s, offers provide recipient privacy.
 330 ///
 331 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 332 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 333 #[derive(Clone, Debug)]
 334 #[cfg_attr(test, derive(PartialEq))]
 335 pub struct Offer {
 336         // The serialized offer. Needed when creating an `InvoiceRequest` if the offer contains unknown
 337         // fields.
 338         pub(super) bytes: Vec<u8>,
 339         pub(super) contents: OfferContents,
 340 }
 341
 342 /// The contents of an [`Offer`], which may be shared with an [`InvoiceRequest`] or a
 343 /// [`Bolt12Invoice`].
 344 ///
 345 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 346 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 347 #[derive(Clone, Debug)]
 348 #[cfg_attr(test, derive(PartialEq))]
 349 pub(super) struct OfferContents {
 350         chains: Option<Vec<ChainHash>>,
 351         metadata: Option<Metadata>,
 352         amount: Option<Amount>,
 353         description: String,
 354         features: OfferFeatures,
 355         absolute_expiry: Option<Duration>,
 356         issuer: Option<String>,
 357         paths: Option<Vec<BlindedPath>>,
 358         supported_quantity: Quantity,
 359         signing_pubkey: PublicKey,
 360 }
 361
 362 macro_rules! offer_accessors { ($self: ident, $contents: expr) => {
 363         // TODO: Return a slice once ChainHash has constants.
 364         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1283
 365         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1286
 366         /// The chains that may be used when paying a requested invoice (e.g., bitcoin mainnet).
 367         /// Payments must be denominated in units of the minimal lightning-payable unit (e.g., msats)
 368         /// for the selected chain.
 369         pub fn chains(&$self) -> Vec<bitcoin::blockdata::constants::ChainHash> {
 370                 $contents.chains()
 371         }
 372
 373         // TODO: Link to corresponding method in `InvoiceRequest`.
 374         /// Opaque bytes set by the originator. Useful for authentication and validating fields since it
 375         /// is reflected in `invoice_request` messages along with all the other fields from the `offer`.
 376         pub fn metadata(&$self) -> Option<&Vec<u8>> {
 377                 $contents.metadata()
 378         }
 379
 380         /// The minimum amount required for a successful payment of a single item.
 381         pub fn amount(&$self) -> Option<&$crate::offers::offer::Amount> {
 382                 $contents.amount()
 383         }
 384
 385         /// A complete description of the purpose of the payment. Intended to be displayed to the user
 386         /// but with the caveat that it has not been verified in any way.
 387         pub fn description(&$self) -> $crate::util::string::PrintableString {
 388                 $contents.description()
 389         }
 390
 391         /// Features pertaining to the offer.
 392         pub fn offer_features(&$self) -> &$crate::ln::features::OfferFeatures {
 393                 &$contents.features()
 394         }
 395
 396         /// Duration since the Unix epoch when an invoice should no longer be requested.
 397         ///
 398         /// If `None`, the offer does not expire.
 399         pub fn absolute_expiry(&$self) -> Option<core::time::Duration> {
 400                 $contents.absolute_expiry()
 401         }
 402
 403         /// The issuer of the offer, possibly beginning with `user@domain` or `domain`. Intended to be
 404         /// displayed to the user but with the caveat that it has not been verified in any way.
 405         pub fn issuer(&$self) -> Option<$crate::util::string::PrintableString> {
 406                 $contents.issuer()
 407         }
 408
 409         /// Paths to the recipient originating from publicly reachable nodes. Blinded paths provide
 410         /// recipient privacy by obfuscating its node id.
 411         pub fn paths(&$self) -> &[$crate::blinded_path::BlindedPath] {
 412                 $contents.paths()
 413         }
 414
 415         /// The quantity of items supported.
 416         pub fn supported_quantity(&$self) -> $crate::offers::offer::Quantity {
 417                 $contents.supported_quantity()
 418         }
 419
 420         /// The public key used by the recipient to sign invoices.
 421         pub fn signing_pubkey(&$self) -> bitcoin::secp256k1::PublicKey {
 422                 $contents.signing_pubkey()
 423         }
 424 } }
 425
 426 impl Offer {
 427         offer_accessors!(self, self.contents);
 428
 429         pub(super) fn implied_chain(&self) -> ChainHash {
 430                 self.contents.implied_chain()
 431         }
 432
 433         /// Returns whether the given chain is supported by the offer.
 434         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 435                 self.contents.supports_chain(chain)
 436         }
 437
 438         /// Whether the offer has expired.
 439         #[cfg(feature = "std")]
 440         pub fn is_expired(&self) -> bool {
 441                 self.contents.is_expired()
 442         }
 443
 444         /// Returns whether the given quantity is valid for the offer.
 445         pub fn is_valid_quantity(&self, quantity: u64) -> bool {
 446                 self.contents.is_valid_quantity(quantity)
 447         }
 448
 449         /// Returns whether a quantity is expected in an [`InvoiceRequest`] for the offer.
 450         ///
 451         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 452         pub fn expects_quantity(&self) -> bool {
 453                 self.contents.expects_quantity()
 454         }
 455
 456         /// Similar to [`Offer::request_invoice`] except it:
 457         /// - derives the [`InvoiceRequest::payer_id`] such that a different key can be used for each
 458         ///   request,
 459         /// - sets [`InvoiceRequest::payer_metadata`] when [`InvoiceRequestBuilder::build`] is called
 460         ///   such that it can be used by [`Bolt12Invoice::verify`] to determine if the invoice was
 461         ///   requested using a base [`ExpandedKey`] from which the payer id was derived, and
 462         /// - includes the [`PaymentId`] encrypted in [`InvoiceRequest::payer_metadata`] so that it can
 463         ///   be used when sending the payment for the requested invoice.
 464         ///
 465         /// Useful to protect the sender's privacy.
 466         ///
 467         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 468         ///
 469         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 470         /// [`InvoiceRequest::payer_metadata`]: crate::offers::invoice_request::InvoiceRequest::payer_metadata
 471         /// [`Bolt12Invoice::verify`]: crate::offers::invoice::Bolt12Invoice::verify
 472         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 473         pub fn request_invoice_deriving_payer_id<'a, 'b, ES: Deref, T: secp256k1::Signing>(
 474                 &'a self, expanded_key: &ExpandedKey, entropy_source: ES, secp_ctx: &'b Secp256k1<T>,
 475                 payment_id: PaymentId
 476         ) -> Result<InvoiceRequestBuilder<'a, 'b, DerivedPayerId, T>, Bolt12SemanticError>
 477         where
 478                 ES::Target: EntropySource,
 479         {
 480                 if self.offer_features().requires_unknown_bits() {
 481                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 482                 }
 483
 484                 Ok(InvoiceRequestBuilder::deriving_payer_id(
 485                         self, expanded_key, entropy_source, secp_ctx, payment_id
 486                 ))
 487         }
 488
 489         /// Similar to [`Offer::request_invoice_deriving_payer_id`] except uses `payer_id` for the
 490         /// [`InvoiceRequest::payer_id`] instead of deriving a different key for each request.
 491         ///
 492         /// Useful for recurring payments using the same `payer_id` with different invoices.
 493         ///
 494         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 495         ///
 496         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 497         pub fn request_invoice_deriving_metadata<ES: Deref>(
 498                 &self, payer_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 499                 payment_id: PaymentId
 500         ) -> Result<InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>, Bolt12SemanticError>
 501         where
 502                 ES::Target: EntropySource,
 503         {
 504                 if self.offer_features().requires_unknown_bits() {
 505                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 506                 }
 507
 508                 Ok(InvoiceRequestBuilder::deriving_metadata(
 509                         self, payer_id, expanded_key, entropy_source, payment_id
 510                 ))
 511         }
 512
 513         /// Creates an [`InvoiceRequestBuilder`] for the offer with the given `metadata` and `payer_id`,
 514         /// which will be reflected in the `Bolt12Invoice` response.
 515         ///
 516         /// The `metadata` is useful for including information about the derivation of `payer_id` such
 517         /// that invoice response handling can be stateless. Also serves as payer-provided entropy while
 518         /// hashing in the signature calculation.
 519         ///
 520         /// This should not leak any information such as by using a simple BIP-32 derivation path.
 521         /// Otherwise, payments may be correlated.
 522         ///
 523         /// Errors if the offer contains unknown required features.
 524         ///
 525         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 526         ///
 527         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 528         pub fn request_invoice(
 529                 &self, metadata: Vec<u8>, payer_id: PublicKey
 530         ) -> Result<InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>, Bolt12SemanticError> {
 531                 if self.offer_features().requires_unknown_bits() {
 532                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 533                 }
 534
 535                 Ok(InvoiceRequestBuilder::new(self, metadata, payer_id))
 536         }
 537
 538         #[cfg(test)]
 539         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 540                 self.contents.as_tlv_stream()
 541         }
 542 }
 543
 544 impl AsRef<[u8]> for Offer {
 545         fn as_ref(&self) -> &[u8] {
 546                 &self.bytes
 547         }
 548 }
 549
 550 impl OfferContents {
 551         pub fn chains(&self) -> Vec<ChainHash> {
 552                 self.chains.as_ref().cloned().unwrap_or_else(|| vec![self.implied_chain()])
 553         }
 554
 555         pub fn implied_chain(&self) -> ChainHash {
 556                 ChainHash::using_genesis_block(Network::Bitcoin)
 557         }
 558
 559         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 560                 self.chains().contains(&chain)
 561         }
 562
 563         pub fn metadata(&self) -> Option<&Vec<u8>> {
 564                 self.metadata.as_ref().and_then(|metadata| metadata.as_bytes())
 565         }
 566
 567         pub fn amount(&self) -> Option<&Amount> {
 568                 self.amount.as_ref()
 569         }
 570
 571         pub fn description(&self) -> PrintableString {
 572                 PrintableString(&self.description)
 573         }
 574
 575         pub fn features(&self) -> &OfferFeatures {
 576                 &self.features
 577         }
 578
 579         pub fn absolute_expiry(&self) -> Option<Duration> {
 580                 self.absolute_expiry
 581         }
 582
 583         #[cfg(feature = "std")]
 584         pub(super) fn is_expired(&self) -> bool {
 585                 match self.absolute_expiry {
 586                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
 587                                 Ok(elapsed) => elapsed > seconds_from_epoch,
 588                                 Err(_) => false,
 589                         },
 590                         None => false,
 591                 }
 592         }
 593
 594         pub fn issuer(&self) -> Option<PrintableString> {
 595                 self.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 596         }
 597
 598         pub fn paths(&self) -> &[BlindedPath] {
 599                 self.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 600         }
 601
 602         pub(super) fn check_amount_msats_for_quantity(
 603                 &self, amount_msats: Option<u64>, quantity: Option<u64>
 604         ) -> Result<(), Bolt12SemanticError> {
 605                 let offer_amount_msats = match self.amount {
 606                         None => 0,
 607                         Some(Amount::Bitcoin { amount_msats }) => amount_msats,
 608                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 609                 };
 610
 611                 if !self.expects_quantity() || quantity.is_some() {
 612                         let expected_amount_msats = offer_amount_msats.checked_mul(quantity.unwrap_or(1))
 613                                 .ok_or(Bolt12SemanticError::InvalidAmount)?;
 614                         let amount_msats = amount_msats.unwrap_or(expected_amount_msats);
 615
 616                         if amount_msats < expected_amount_msats {
 617                                 return Err(Bolt12SemanticError::InsufficientAmount);
 618                         }
 619
 620                         if amount_msats > MAX_VALUE_MSAT {
 621                                 return Err(Bolt12SemanticError::InvalidAmount);
 622                         }
 623                 }
 624
 625                 Ok(())
 626         }
 627
 628         pub fn supported_quantity(&self) -> Quantity {
 629                 self.supported_quantity
 630         }
 631
 632         pub(super) fn check_quantity(&self, quantity: Option<u64>) -> Result<(), Bolt12SemanticError> {
 633                 let expects_quantity = self.expects_quantity();
 634                 match quantity {
 635                         None if expects_quantity => Err(Bolt12SemanticError::MissingQuantity),
 636                         Some(_) if !expects_quantity => Err(Bolt12SemanticError::UnexpectedQuantity),
 637                         Some(quantity) if !self.is_valid_quantity(quantity) => {
 638                                 Err(Bolt12SemanticError::InvalidQuantity)
 639                         },
 640                         _ => Ok(()),
 641                 }
 642         }
 643
 644         fn is_valid_quantity(&self, quantity: u64) -> bool {
 645                 match self.supported_quantity {
 646                         Quantity::Bounded(n) => quantity <= n.get(),
 647                         Quantity::Unbounded => quantity > 0,
 648                         Quantity::One => quantity == 1,
 649                 }
 650         }
 651
 652         fn expects_quantity(&self) -> bool {
 653                 match self.supported_quantity {
 654                         Quantity::Bounded(_) => true,
 655                         Quantity::Unbounded => true,
 656                         Quantity::One => false,
 657                 }
 658         }
 659
 660         pub(super) fn signing_pubkey(&self) -> PublicKey {
 661                 self.signing_pubkey
 662         }
 663
 664         /// Verifies that the offer metadata was produced from the offer in the TLV stream.
 665         pub(super) fn verify<T: secp256k1::Signing>(
 666                 &self, bytes: &[u8], key: &ExpandedKey, secp_ctx: &Secp256k1<T>
 667         ) -> Result<Option<KeyPair>, ()> {
 668                 match self.metadata() {
 669                         Some(metadata) => {
 670                                 let tlv_stream = TlvStream::new(bytes).range(OFFER_TYPES).filter(|record| {
 671                                         match record.r#type {
 672                                                 OFFER_METADATA_TYPE => false,
 673                                                 OFFER_NODE_ID_TYPE => {
 674                                                         !self.metadata.as_ref().unwrap().derives_recipient_keys()
 675                                                 },
 676                                                 _ => true,
 677                                         }
 678                                 });
 679                                 signer::verify_recipient_metadata(
 680                                         metadata, key, IV_BYTES, self.signing_pubkey(), tlv_stream, secp_ctx
 681                                 )
 682                         },
 683                         None => Err(()),
 684                 }
 685         }
 686
 687         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 688                 let (currency, amount) = match &self.amount {
 689                         None => (None, None),
 690                         Some(Amount::Bitcoin { amount_msats }) => (None, Some(*amount_msats)),
 691                         Some(Amount::Currency { iso4217_code, amount }) => (
 692                                 Some(iso4217_code), Some(*amount)
 693                         ),
 694                 };
 695
 696                 let features = {
 697                         if self.features == OfferFeatures::empty() { None } else { Some(&self.features) }
 698                 };
 699
 700                 OfferTlvStreamRef {
 701                         chains: self.chains.as_ref(),
 702                         metadata: self.metadata(),
 703                         currency,
 704                         amount,
 705                         description: Some(&self.description),
 706                         features,
 707                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 708                         paths: self.paths.as_ref(),
 709                         issuer: self.issuer.as_ref(),
 710                         quantity_max: self.supported_quantity.to_tlv_record(),
 711                         node_id: Some(&self.signing_pubkey),
 712                 }
 713         }
 714 }
 715
 716 impl Writeable for Offer {
 717         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 718                 WithoutLength(&self.bytes).write(writer)
 719         }
 720 }
 721
 722 impl Writeable for OfferContents {
 723         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 724                 self.as_tlv_stream().write(writer)
 725         }
 726 }
 727
 728 /// The minimum amount required for an item in an [`Offer`], denominated in either bitcoin or
 729 /// another currency.
 730 #[derive(Clone, Debug, PartialEq)]
 731 pub enum Amount {
 732         /// An amount of bitcoin.
 733         Bitcoin {
 734                 /// The amount in millisatoshi.
 735                 amount_msats: u64,
 736         },
 737         /// An amount of currency specified using ISO 4712.
 738         Currency {
 739                 /// The currency that the amount is denominated in.
 740                 iso4217_code: CurrencyCode,
 741                 /// The amount in the currency unit adjusted by the ISO 4712 exponent (e.g., USD cents).
 742                 amount: u64,
 743         },
 744 }
 745
 746 /// An ISO 4712 three-letter currency code (e.g., USD).
 747 pub type CurrencyCode = [u8; 3];
 748
 749 /// Quantity of items supported by an [`Offer`].
 750 #[derive(Clone, Copy, Debug, PartialEq)]
 751 pub enum Quantity {
 752         /// Up to a specific number of items (inclusive). Use when more than one item can be requested
 753         /// but is limited (e.g., because of per customer or inventory limits).
 754         ///
 755         /// May be used with `NonZeroU64::new(1)` but prefer to use [`Quantity::One`] if only one item
 756         /// is supported.
 757         Bounded(NonZeroU64),
 758         /// One or more items. Use when more than one item can be requested without any limit.
 759         Unbounded,
 760         /// Only one item. Use when only a single item can be requested.
 761         One,
 762 }
 763
 764 impl Quantity {
 765         fn to_tlv_record(&self) -> Option<u64> {
 766                 match self {
 767                         Quantity::Bounded(n) => Some(n.get()),
 768                         Quantity::Unbounded => Some(0),
 769                         Quantity::One => None,
 770                 }
 771         }
 772 }
 773
 774 /// Valid type range for offer TLV records.
 775 pub(super) const OFFER_TYPES: core::ops::Range<u64> = 1..80;
 776
 777 /// TLV record type for [`Offer::metadata`].
 778 const OFFER_METADATA_TYPE: u64 = 4;
 779
 780 /// TLV record type for [`Offer::signing_pubkey`].
 781 const OFFER_NODE_ID_TYPE: u64 = 22;
 782
 783 tlv_stream!(OfferTlvStream, OfferTlvStreamRef, OFFER_TYPES, {
 784         (2, chains: (Vec<ChainHash>, WithoutLength)),
 785         (OFFER_METADATA_TYPE, metadata: (Vec<u8>, WithoutLength)),
 786         (6, currency: CurrencyCode),
 787         (8, amount: (u64, HighZeroBytesDroppedBigSize)),
 788         (10, description: (String, WithoutLength)),
 789         (12, features: (OfferFeatures, WithoutLength)),
 790         (14, absolute_expiry: (u64, HighZeroBytesDroppedBigSize)),
 791         (16, paths: (Vec<BlindedPath>, WithoutLength)),
 792         (18, issuer: (String, WithoutLength)),
 793         (20, quantity_max: (u64, HighZeroBytesDroppedBigSize)),
 794         (OFFER_NODE_ID_TYPE, node_id: PublicKey),
 795 });
 796
 797 impl Bech32Encode for Offer {
 798         const BECH32_HRP: &'static str = "lno";
 799 }
 800
 801 impl FromStr for Offer {
 802         type Err = Bolt12ParseError;
 803
 804         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 805                 Self::from_bech32_str(s)
 806         }
 807 }
 808
 809 impl TryFrom<Vec<u8>> for Offer {
 810         type Error = Bolt12ParseError;
 811
 812         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 813                 let offer = ParsedMessage::<OfferTlvStream>::try_from(bytes)?;
 814                 let ParsedMessage { bytes, tlv_stream } = offer;
 815                 let contents = OfferContents::try_from(tlv_stream)?;
 816                 Ok(Offer { bytes, contents })
 817         }
 818 }
 819
 820 impl TryFrom<OfferTlvStream> for OfferContents {
 821         type Error = Bolt12SemanticError;
 822
 823         fn try_from(tlv_stream: OfferTlvStream) -> Result<Self, Self::Error> {
 824                 let OfferTlvStream {
 825                         chains, metadata, currency, amount, description, features, absolute_expiry, paths,
 826                         issuer, quantity_max, node_id,
 827                 } = tlv_stream;
 828
 829                 let metadata = metadata.map(|metadata| Metadata::Bytes(metadata));
 830
 831                 let amount = match (currency, amount) {
 832                         (None, None) => None,
 833                         (None, Some(amount_msats)) if amount_msats > MAX_VALUE_MSAT => {
 834                                 return Err(Bolt12SemanticError::InvalidAmount);
 835                         },
 836                         (None, Some(amount_msats)) => Some(Amount::Bitcoin { amount_msats }),
 837                         (Some(_), None) => return Err(Bolt12SemanticError::MissingAmount),
 838                         (Some(iso4217_code), Some(amount)) => Some(Amount::Currency { iso4217_code, amount }),
 839                 };
 840
 841                 let description = match description {
 842                         None => return Err(Bolt12SemanticError::MissingDescription),
 843                         Some(description) => description,
 844                 };
 845
 846                 let features = features.unwrap_or_else(OfferFeatures::empty);
 847
 848                 let absolute_expiry = absolute_expiry
 849                         .map(|seconds_from_epoch| Duration::from_secs(seconds_from_epoch));
 850
 851                 let supported_quantity = match quantity_max {
 852                         None => Quantity::One,
 853                         Some(0) => Quantity::Unbounded,
 854                         Some(n) => Quantity::Bounded(NonZeroU64::new(n).unwrap()),
 855                 };
 856
 857                 let signing_pubkey = match node_id {
 858                         None => return Err(Bolt12SemanticError::MissingSigningPubkey),
 859                         Some(node_id) => node_id,
 860                 };
 861
 862                 Ok(OfferContents {
 863                         chains, metadata, amount, description, features, absolute_expiry, issuer, paths,
 864                         supported_quantity, signing_pubkey,
 865                 })
 866         }
 867 }
 868
 869 impl core::fmt::Display for Offer {
 870         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 871                 self.fmt_bech32_str(f)
 872         }
 873 }
 874
 875 #[cfg(test)]
 876 mod tests {
 877         use super::{Amount, Offer, OfferBuilder, OfferTlvStreamRef, Quantity};
 878
 879         use bitcoin::blockdata::constants::ChainHash;
 880         use bitcoin::network::constants::Network;
 881         use bitcoin::secp256k1::Secp256k1;
 882         use core::convert::TryFrom;
 883         use core::num::NonZeroU64;
 884         use core::time::Duration;
 885         use crate::blinded_path::{BlindedHop, BlindedPath};
 886         use crate::sign::KeyMaterial;
 887         use crate::ln::features::OfferFeatures;
 888         use crate::ln::inbound_payment::ExpandedKey;
 889         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 890         use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
 891         use crate::offers::test_utils::*;
 892         use crate::util::ser::{BigSize, Writeable};
 893         use crate::util::string::PrintableString;
 894
 895         #[test]
 896         fn builds_offer_with_defaults() {
 897                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
 898
 899                 let mut buffer = Vec::new();
 900                 offer.write(&mut buffer).unwrap();
 901
 902                 assert_eq!(offer.bytes, buffer.as_slice());
 903                 assert_eq!(offer.chains(), vec![ChainHash::using_genesis_block(Network::Bitcoin)]);
 904                 assert!(offer.supports_chain(ChainHash::using_genesis_block(Network::Bitcoin)));
 905                 assert_eq!(offer.metadata(), None);
 906                 assert_eq!(offer.amount(), None);
 907                 assert_eq!(offer.description(), PrintableString("foo"));
 908                 assert_eq!(offer.offer_features(), &OfferFeatures::empty());
 909                 assert_eq!(offer.absolute_expiry(), None);
 910                 #[cfg(feature = "std")]
 911                 assert!(!offer.is_expired());
 912                 assert_eq!(offer.paths(), &[]);
 913                 assert_eq!(offer.issuer(), None);
 914                 assert_eq!(offer.supported_quantity(), Quantity::One);
 915                 assert_eq!(offer.signing_pubkey(), pubkey(42));
 916
 917                 assert_eq!(
 918                         offer.as_tlv_stream(),
 919                         OfferTlvStreamRef {
 920                                 chains: None,
 921                                 metadata: None,
 922                                 currency: None,
 923                                 amount: None,
 924                                 description: Some(&String::from("foo")),
 925                                 features: None,
 926                                 absolute_expiry: None,
 927                                 paths: None,
 928                                 issuer: None,
 929                                 quantity_max: None,
 930                                 node_id: Some(&pubkey(42)),
 931                         },
 932                 );
 933
 934                 if let Err(e) = Offer::try_from(buffer) {
 935                         panic!("error parsing offer: {:?}", e);
 936                 }
 937         }
 938
 939         #[test]
 940         fn builds_offer_with_chains() {
 941                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
 942                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
 943
 944                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 945                         .chain(Network::Bitcoin)
 946                         .build()
 947                         .unwrap();
 948                 assert!(offer.supports_chain(mainnet));
 949                 assert_eq!(offer.chains(), vec![mainnet]);
 950                 assert_eq!(offer.as_tlv_stream().chains, None);
 951
 952                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 953                         .chain(Network::Testnet)
 954                         .build()
 955                         .unwrap();
 956                 assert!(offer.supports_chain(testnet));
 957                 assert_eq!(offer.chains(), vec![testnet]);
 958                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 959
 960                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 961                         .chain(Network::Testnet)
 962                         .chain(Network::Testnet)
 963                         .build()
 964                         .unwrap();
 965                 assert!(offer.supports_chain(testnet));
 966                 assert_eq!(offer.chains(), vec![testnet]);
 967                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 968
 969                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 970                         .chain(Network::Bitcoin)
 971                         .chain(Network::Testnet)
 972                         .build()
 973                         .unwrap();
 974                 assert!(offer.supports_chain(mainnet));
 975                 assert!(offer.supports_chain(testnet));
 976                 assert_eq!(offer.chains(), vec![mainnet, testnet]);
 977                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![mainnet, testnet]));
 978         }
 979
 980         #[test]
 981         fn builds_offer_with_metadata() {
 982                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 983                         .metadata(vec![42; 32]).unwrap()
 984                         .build()
 985                         .unwrap();
 986                 assert_eq!(offer.metadata(), Some(&vec![42; 32]));
 987                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![42; 32]));
 988
 989                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 990                         .metadata(vec![42; 32]).unwrap()
 991                         .metadata(vec![43; 32]).unwrap()
 992                         .build()
 993                         .unwrap();
 994                 assert_eq!(offer.metadata(), Some(&vec![43; 32]));
 995                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![43; 32]));
 996         }
 997
 998         #[test]
 999         fn builds_offer_with_metadata_derived() {
1000                 let desc = "foo".to_string();
1001                 let node_id = recipient_pubkey();
1002                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1003                 let entropy = FixedEntropy {};
1004                 let secp_ctx = Secp256k1::new();
1005
1006                 let offer = OfferBuilder
1007                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
1008                         .amount_msats(1000)
1009                         .build().unwrap();
1010                 assert_eq!(offer.signing_pubkey(), node_id);
1011
1012                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1013                         .build().unwrap()
1014                         .sign(payer_sign).unwrap();
1015                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
1016
1017                 // Fails verification with altered offer field
1018                 let mut tlv_stream = offer.as_tlv_stream();
1019                 tlv_stream.amount = Some(100);
1020
1021                 let mut encoded_offer = Vec::new();
1022                 tlv_stream.write(&mut encoded_offer).unwrap();
1023
1024                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1025                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1026                         .build().unwrap()
1027                         .sign(payer_sign).unwrap();
1028                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1029
1030                 // Fails verification with altered metadata
1031                 let mut tlv_stream = offer.as_tlv_stream();
1032                 let metadata = tlv_stream.metadata.unwrap().iter().copied().rev().collect();
1033                 tlv_stream.metadata = Some(&metadata);
1034
1035                 let mut encoded_offer = Vec::new();
1036                 tlv_stream.write(&mut encoded_offer).unwrap();
1037
1038                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1039                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1040                         .build().unwrap()
1041                         .sign(payer_sign).unwrap();
1042                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1043         }
1044
1045         #[test]
1046         fn builds_offer_with_derived_signing_pubkey() {
1047                 let desc = "foo".to_string();
1048                 let node_id = recipient_pubkey();
1049                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1050                 let entropy = FixedEntropy {};
1051                 let secp_ctx = Secp256k1::new();
1052
1053                 let blinded_path = BlindedPath {
1054                         introduction_node_id: pubkey(40),
1055                         blinding_point: pubkey(41),
1056                         blinded_hops: vec![
1057                                 BlindedHop { blinded_node_id: pubkey(42), encrypted_payload: vec![0; 43] },
1058                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
1059                         ],
1060                 };
1061
1062                 let offer = OfferBuilder
1063                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
1064                         .amount_msats(1000)
1065                         .path(blinded_path)
1066                         .build().unwrap();
1067                 assert_ne!(offer.signing_pubkey(), node_id);
1068
1069                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1070                         .build().unwrap()
1071                         .sign(payer_sign).unwrap();
1072                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
1073
1074                 // Fails verification with altered offer field
1075                 let mut tlv_stream = offer.as_tlv_stream();
1076                 tlv_stream.amount = Some(100);
1077
1078                 let mut encoded_offer = Vec::new();
1079                 tlv_stream.write(&mut encoded_offer).unwrap();
1080
1081                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1082                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1083                         .build().unwrap()
1084                         .sign(payer_sign).unwrap();
1085                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1086
1087                 // Fails verification with altered signing pubkey
1088                 let mut tlv_stream = offer.as_tlv_stream();
1089                 let signing_pubkey = pubkey(1);
1090                 tlv_stream.node_id = Some(&signing_pubkey);
1091
1092                 let mut encoded_offer = Vec::new();
1093                 tlv_stream.write(&mut encoded_offer).unwrap();
1094
1095                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1096                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1097                         .build().unwrap()
1098                         .sign(payer_sign).unwrap();
1099                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1100         }
1101
1102         #[test]
1103         fn builds_offer_with_amount() {
1104                 let bitcoin_amount = Amount::Bitcoin { amount_msats: 1000 };
1105                 let currency_amount = Amount::Currency { iso4217_code: *b"USD", amount: 10 };
1106
1107                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1108                         .amount_msats(1000)
1109                         .build()
1110                         .unwrap();
1111                 let tlv_stream = offer.as_tlv_stream();
1112                 assert_eq!(offer.amount(), Some(&bitcoin_amount));
1113                 assert_eq!(tlv_stream.amount, Some(1000));
1114                 assert_eq!(tlv_stream.currency, None);
1115
1116                 let builder = OfferBuilder::new("foo".into(), pubkey(42))
1117                         .amount(currency_amount.clone());
1118                 let tlv_stream = builder.offer.as_tlv_stream();
1119                 assert_eq!(builder.offer.amount, Some(currency_amount.clone()));
1120                 assert_eq!(tlv_stream.amount, Some(10));
1121                 assert_eq!(tlv_stream.currency, Some(b"USD"));
1122                 match builder.build() {
1123                         Ok(_) => panic!("expected error"),
1124                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnsupportedCurrency),
1125                 }
1126
1127                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1128                         .amount(currency_amount.clone())
1129                         .amount(bitcoin_amount.clone())
1130                         .build()
1131                         .unwrap();
1132                 let tlv_stream = offer.as_tlv_stream();
1133                 assert_eq!(tlv_stream.amount, Some(1000));
1134                 assert_eq!(tlv_stream.currency, None);
1135
1136                 let invalid_amount = Amount::Bitcoin { amount_msats: MAX_VALUE_MSAT + 1 };
1137                 match OfferBuilder::new("foo".into(), pubkey(42)).amount(invalid_amount).build() {
1138                         Ok(_) => panic!("expected error"),
1139                         Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
1140                 }
1141         }
1142
1143         #[test]
1144         fn builds_offer_with_features() {
1145                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1146                         .features_unchecked(OfferFeatures::unknown())
1147                         .build()
1148                         .unwrap();
1149                 assert_eq!(offer.offer_features(), &OfferFeatures::unknown());
1150                 assert_eq!(offer.as_tlv_stream().features, Some(&OfferFeatures::unknown()));
1151
1152                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1153                         .features_unchecked(OfferFeatures::unknown())
1154                         .features_unchecked(OfferFeatures::empty())
1155                         .build()
1156                         .unwrap();
1157                 assert_eq!(offer.offer_features(), &OfferFeatures::empty());
1158                 assert_eq!(offer.as_tlv_stream().features, None);
1159         }
1160
1161         #[test]
1162         fn builds_offer_with_absolute_expiry() {
1163                 let future_expiry = Duration::from_secs(u64::max_value());
1164                 let past_expiry = Duration::from_secs(0);
1165
1166                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1167                         .absolute_expiry(future_expiry)
1168                         .build()
1169                         .unwrap();
1170                 #[cfg(feature = "std")]
1171                 assert!(!offer.is_expired());
1172                 assert_eq!(offer.absolute_expiry(), Some(future_expiry));
1173                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(future_expiry.as_secs()));
1174
1175                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1176                         .absolute_expiry(future_expiry)
1177                         .absolute_expiry(past_expiry)
1178                         .build()
1179                         .unwrap();
1180                 #[cfg(feature = "std")]
1181                 assert!(offer.is_expired());
1182                 assert_eq!(offer.absolute_expiry(), Some(past_expiry));
1183                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(past_expiry.as_secs()));
1184         }
1185
1186         #[test]
1187         fn builds_offer_with_paths() {
1188                 let paths = vec![
1189                         BlindedPath {
1190                                 introduction_node_id: pubkey(40),
1191                                 blinding_point: pubkey(41),
1192                                 blinded_hops: vec![
1193                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1194                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1195                                 ],
1196                         },
1197                         BlindedPath {
1198                                 introduction_node_id: pubkey(40),
1199                                 blinding_point: pubkey(41),
1200                                 blinded_hops: vec![
1201                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1202                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1203                                 ],
1204                         },
1205                 ];
1206
1207                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1208                         .path(paths[0].clone())
1209                         .path(paths[1].clone())
1210                         .build()
1211                         .unwrap();
1212                 let tlv_stream = offer.as_tlv_stream();
1213                 assert_eq!(offer.paths(), paths.as_slice());
1214                 assert_eq!(offer.signing_pubkey(), pubkey(42));
1215                 assert_ne!(pubkey(42), pubkey(44));
1216                 assert_eq!(tlv_stream.paths, Some(&paths));
1217                 assert_eq!(tlv_stream.node_id, Some(&pubkey(42)));
1218         }
1219
1220         #[test]
1221         fn builds_offer_with_issuer() {
1222                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1223                         .issuer("bar".into())
1224                         .build()
1225                         .unwrap();
1226                 assert_eq!(offer.issuer(), Some(PrintableString("bar")));
1227                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("bar")));
1228
1229                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1230                         .issuer("bar".into())
1231                         .issuer("baz".into())
1232                         .build()
1233                         .unwrap();
1234                 assert_eq!(offer.issuer(), Some(PrintableString("baz")));
1235                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("baz")));
1236         }
1237
1238         #[test]
1239         fn builds_offer_with_supported_quantity() {
1240                 let one = NonZeroU64::new(1).unwrap();
1241                 let ten = NonZeroU64::new(10).unwrap();
1242
1243                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1244                         .supported_quantity(Quantity::One)
1245                         .build()
1246                         .unwrap();
1247                 let tlv_stream = offer.as_tlv_stream();
1248                 assert_eq!(offer.supported_quantity(), Quantity::One);
1249                 assert_eq!(tlv_stream.quantity_max, None);
1250
1251                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1252                         .supported_quantity(Quantity::Unbounded)
1253                         .build()
1254                         .unwrap();
1255                 let tlv_stream = offer.as_tlv_stream();
1256                 assert_eq!(offer.supported_quantity(), Quantity::Unbounded);
1257                 assert_eq!(tlv_stream.quantity_max, Some(0));
1258
1259                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1260                         .supported_quantity(Quantity::Bounded(ten))
1261                         .build()
1262                         .unwrap();
1263                 let tlv_stream = offer.as_tlv_stream();
1264                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(ten));
1265                 assert_eq!(tlv_stream.quantity_max, Some(10));
1266
1267                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1268                         .supported_quantity(Quantity::Bounded(one))
1269                         .build()
1270                         .unwrap();
1271                 let tlv_stream = offer.as_tlv_stream();
1272                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(one));
1273                 assert_eq!(tlv_stream.quantity_max, Some(1));
1274
1275                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1276                         .supported_quantity(Quantity::Bounded(ten))
1277                         .supported_quantity(Quantity::One)
1278                         .build()
1279                         .unwrap();
1280                 let tlv_stream = offer.as_tlv_stream();
1281                 assert_eq!(offer.supported_quantity(), Quantity::One);
1282                 assert_eq!(tlv_stream.quantity_max, None);
1283         }
1284
1285         #[test]
1286         fn fails_requesting_invoice_with_unknown_required_features() {
1287                 match OfferBuilder::new("foo".into(), pubkey(42))
1288                         .features_unchecked(OfferFeatures::unknown())
1289                         .build().unwrap()
1290                         .request_invoice(vec![1; 32], pubkey(43))
1291                 {
1292                         Ok(_) => panic!("expected error"),
1293                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnknownRequiredFeatures),
1294                 }
1295         }
1296
1297         #[test]
1298         fn parses_offer_with_chains() {
1299                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1300                         .chain(Network::Bitcoin)
1301                         .chain(Network::Testnet)
1302                         .build()
1303                         .unwrap();
1304                 if let Err(e) = offer.to_string().parse::<Offer>() {
1305                         panic!("error parsing offer: {:?}", e);
1306                 }
1307         }
1308
1309         #[test]
1310         fn parses_offer_with_amount() {
1311                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1312                         .amount(Amount::Bitcoin { amount_msats: 1000 })
1313                         .build()
1314                         .unwrap();
1315                 if let Err(e) = offer.to_string().parse::<Offer>() {
1316                         panic!("error parsing offer: {:?}", e);
1317                 }
1318
1319                 let mut tlv_stream = offer.as_tlv_stream();
1320                 tlv_stream.amount = Some(1000);
1321                 tlv_stream.currency = Some(b"USD");
1322
1323                 let mut encoded_offer = Vec::new();
1324                 tlv_stream.write(&mut encoded_offer).unwrap();
1325
1326                 if let Err(e) = Offer::try_from(encoded_offer) {
1327                         panic!("error parsing offer: {:?}", e);
1328                 }
1329
1330                 let mut tlv_stream = offer.as_tlv_stream();
1331                 tlv_stream.amount = None;
1332                 tlv_stream.currency = Some(b"USD");
1333
1334                 let mut encoded_offer = Vec::new();
1335                 tlv_stream.write(&mut encoded_offer).unwrap();
1336
1337                 match Offer::try_from(encoded_offer) {
1338                         Ok(_) => panic!("expected error"),
1339                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingAmount)),
1340                 }
1341
1342                 let mut tlv_stream = offer.as_tlv_stream();
1343                 tlv_stream.amount = Some(MAX_VALUE_MSAT + 1);
1344                 tlv_stream.currency = None;
1345
1346                 let mut encoded_offer = Vec::new();
1347                 tlv_stream.write(&mut encoded_offer).unwrap();
1348
1349                 match Offer::try_from(encoded_offer) {
1350                         Ok(_) => panic!("expected error"),
1351                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InvalidAmount)),
1352                 }
1353         }
1354
1355         #[test]
1356         fn parses_offer_with_description() {
1357                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1358                 if let Err(e) = offer.to_string().parse::<Offer>() {
1359                         panic!("error parsing offer: {:?}", e);
1360                 }
1361
1362                 let mut tlv_stream = offer.as_tlv_stream();
1363                 tlv_stream.description = None;
1364
1365                 let mut encoded_offer = Vec::new();
1366                 tlv_stream.write(&mut encoded_offer).unwrap();
1367
1368                 match Offer::try_from(encoded_offer) {
1369                         Ok(_) => panic!("expected error"),
1370                         Err(e) => {
1371                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription));
1372                         },
1373                 }
1374         }
1375
1376         #[test]
1377         fn parses_offer_with_paths() {
1378                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1379                         .path(BlindedPath {
1380                                 introduction_node_id: pubkey(40),
1381                                 blinding_point: pubkey(41),
1382                                 blinded_hops: vec![
1383                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1384                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1385                                 ],
1386                         })
1387                         .path(BlindedPath {
1388                                 introduction_node_id: pubkey(40),
1389                                 blinding_point: pubkey(41),
1390                                 blinded_hops: vec![
1391                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1392                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1393                                 ],
1394                         })
1395                         .build()
1396                         .unwrap();
1397                 if let Err(e) = offer.to_string().parse::<Offer>() {
1398                         panic!("error parsing offer: {:?}", e);
1399                 }
1400
1401                 let mut builder = OfferBuilder::new("foo".into(), pubkey(42));
1402                 builder.offer.paths = Some(vec![]);
1403
1404                 let offer = builder.build().unwrap();
1405                 if let Err(e) = offer.to_string().parse::<Offer>() {
1406                         panic!("error parsing offer: {:?}", e);
1407                 }
1408         }
1409
1410         #[test]
1411         fn parses_offer_with_quantity() {
1412                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1413                         .supported_quantity(Quantity::One)
1414                         .build()
1415                         .unwrap();
1416                 if let Err(e) = offer.to_string().parse::<Offer>() {
1417                         panic!("error parsing offer: {:?}", e);
1418                 }
1419
1420                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1421                         .supported_quantity(Quantity::Unbounded)
1422                         .build()
1423                         .unwrap();
1424                 if let Err(e) = offer.to_string().parse::<Offer>() {
1425                         panic!("error parsing offer: {:?}", e);
1426                 }
1427
1428                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1429                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(10).unwrap()))
1430                         .build()
1431                         .unwrap();
1432                 if let Err(e) = offer.to_string().parse::<Offer>() {
1433                         panic!("error parsing offer: {:?}", e);
1434                 }
1435
1436                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1437                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(1).unwrap()))
1438                         .build()
1439                         .unwrap();
1440                 if let Err(e) = offer.to_string().parse::<Offer>() {
1441                         panic!("error parsing offer: {:?}", e);
1442                 }
1443         }
1444
1445         #[test]
1446         fn parses_offer_with_node_id() {
1447                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1448                 if let Err(e) = offer.to_string().parse::<Offer>() {
1449                         panic!("error parsing offer: {:?}", e);
1450                 }
1451
1452                 let mut tlv_stream = offer.as_tlv_stream();
1453                 tlv_stream.node_id = None;
1454
1455                 let mut encoded_offer = Vec::new();
1456                 tlv_stream.write(&mut encoded_offer).unwrap();
1457
1458                 match Offer::try_from(encoded_offer) {
1459                         Ok(_) => panic!("expected error"),
1460                         Err(e) => {
1461                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingSigningPubkey));
1462                         },
1463                 }
1464         }
1465
1466         #[test]
1467         fn fails_parsing_offer_with_extra_tlv_records() {
1468                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1469
1470                 let mut encoded_offer = Vec::new();
1471                 offer.write(&mut encoded_offer).unwrap();
1472                 BigSize(80).write(&mut encoded_offer).unwrap();
1473                 BigSize(32).write(&mut encoded_offer).unwrap();
1474                 [42u8; 32].write(&mut encoded_offer).unwrap();
1475
1476                 match Offer::try_from(encoded_offer) {
1477                         Ok(_) => panic!("expected error"),
1478                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1479                 }
1480         }
1481 }
1482
1483 #[cfg(test)]
1484 mod bech32_tests {
1485         use super::{Bolt12ParseError, Offer};
1486         use bitcoin::bech32;
1487         use crate::ln::msgs::DecodeError;
1488
1489         #[test]
1490         fn encodes_offer_as_bech32_without_checksum() {
1491                 let encoded_offer = "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg";
1492                 let offer = dbg!(encoded_offer.parse::<Offer>().unwrap());
1493                 let reencoded_offer = offer.to_string();
1494                 dbg!(reencoded_offer.parse::<Offer>().unwrap());
1495                 assert_eq!(reencoded_offer, encoded_offer);
1496         }
1497
1498         #[test]
1499         fn parses_bech32_encoded_offers() {
1500                 let offers = [
1501                         // BOLT 12 test vectors
1502                         "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1503                         "l+no1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1504                         "lno1pqps7sjqpgt+yzm3qv4uxzmtsd3jjqer9wd3hy6tsw3+5k7msjzfpy7nz5yqcn+ygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd+5xvxg",
1505                         "lno1pqps7sjqpgt+ yzm3qv4uxzmtsd3jjqer9wd3hy6tsw3+  5k7msjzfpy7nz5yqcn+\nygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd+\r\n 5xvxg",
1506                 ];
1507                 for encoded_offer in &offers {
1508                         if let Err(e) = encoded_offer.parse::<Offer>() {
1509                                 panic!("Invalid offer ({:?}): {}", e, encoded_offer);
1510                         }
1511                 }
1512         }
1513
1514         #[test]
1515         fn fails_parsing_bech32_encoded_offers_with_invalid_continuations() {
1516                 let offers = [
1517                         // BOLT 12 test vectors
1518                         "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg+",
1519                         "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg+ ",
1520                         "+lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1521                         "+ lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1522                         "ln++o1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1523                 ];
1524                 for encoded_offer in &offers {
1525                         match encoded_offer.parse::<Offer>() {
1526                                 Ok(_) => panic!("Valid offer: {}", encoded_offer),
1527                                 Err(e) => assert_eq!(e, Bolt12ParseError::InvalidContinuation),
1528                         }
1529                 }
1530
1531         }
1532
1533         #[test]
1534         fn fails_parsing_bech32_encoded_offer_with_invalid_hrp() {
1535                 let encoded_offer = "lni1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg";
1536                 match encoded_offer.parse::<Offer>() {
1537                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1538                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidBech32Hrp),
1539                 }
1540         }
1541
1542         #[test]
1543         fn fails_parsing_bech32_encoded_offer_with_invalid_bech32_data() {
1544                 let encoded_offer = "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxo";
1545                 match encoded_offer.parse::<Offer>() {
1546                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1547                         Err(e) => assert_eq!(e, Bolt12ParseError::Bech32(bech32::Error::InvalidChar('o'))),
1548                 }
1549         }
1550
1551         #[test]
1552         fn fails_parsing_bech32_encoded_offer_with_invalid_tlv_data() {
1553                 let encoded_offer = "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxgqqqqq";
1554                 match encoded_offer.parse::<Offer>() {
1555                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1556                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1557                 }
1558         }
1559 }