_ 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 //! # Example
  17 //!
  18 //! ```
  19 //! extern crate bitcoin;
  20 //! extern crate core;
  21 //! extern crate lightning;
  22 //!
  23 //! use core::convert::TryFrom;
  24 //! use core::num::NonZeroU64;
  25 //! use core::time::Duration;
  26 //!
  27 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
  28 //! use lightning::offers::offer::{Offer, OfferBuilder, Quantity};
  29 //! use lightning::offers::parse::Bolt12ParseError;
  30 //! use lightning::util::ser::{Readable, Writeable};
  31 //!
  32 //! # use lightning::blinded_path::BlindedPath;
  33 //! # #[cfg(feature = "std")]
  34 //! # use std::time::SystemTime;
  35 //! #
  36 //! # fn create_blinded_path() -> BlindedPath { unimplemented!() }
  37 //! # fn create_another_blinded_path() -> BlindedPath { unimplemented!() }
  38 //! #
  39 //! # #[cfg(feature = "std")]
  40 //! # fn build() -> Result<(), Bolt12ParseError> {
  41 //! let secp_ctx = Secp256k1::new();
  42 //! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
  43 //! let pubkey = PublicKey::from(keys);
  44 //!
  45 //! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
  46 //! let offer = OfferBuilder::new("coffee, large".to_string(), pubkey)
  47 //!     .amount_msats(20_000)
  48 //!     .supported_quantity(Quantity::Unbounded)
  49 //!     .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
  50 //!     .issuer("Foo Bar".to_string())
  51 //!     .path(create_blinded_path())
  52 //!     .path(create_another_blinded_path())
  53 //!     .build()?;
  54 //!
  55 //! // Encode as a bech32 string for use in a QR code.
  56 //! let encoded_offer = offer.to_string();
  57 //!
  58 //! // Parse from a bech32 string after scanning from a QR code.
  59 //! let offer = encoded_offer.parse::<Offer>()?;
  60 //!
  61 //! // Encode offer as raw bytes.
  62 //! let mut bytes = Vec::new();
  63 //! offer.write(&mut bytes).unwrap();
  64 //!
  65 //! // Decode raw bytes into an offer.
  66 //! let offer = Offer::try_from(bytes)?;
  67 //! # Ok(())
  68 //! # }
  69 //! ```
  70 //!
  71 //! # Note
  72 //!
  73 //! If constructing an [`Offer`] for use with a [`ChannelManager`], use
  74 //! [`ChannelManager::create_offer_builder`] instead of [`OfferBuilder::new`].
  75 //!
  76 //! [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
  77 //! [`ChannelManager::create_offer_builder`]: crate::ln::channelmanager::ChannelManager::create_offer_builder
  78
  79 use bitcoin::blockdata::constants::ChainHash;
  80 use bitcoin::network::constants::Network;
  81 use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, self};
  82 use core::convert::TryFrom;
  83 use core::num::NonZeroU64;
  84 use core::ops::Deref;
  85 use core::str::FromStr;
  86 use core::time::Duration;
  87 use crate::sign::EntropySource;
  88 use crate::io;
  89 use crate::blinded_path::BlindedPath;
  90 use crate::ln::channelmanager::PaymentId;
  91 use crate::ln::features::OfferFeatures;
  92 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
  93 use crate::ln::msgs::MAX_VALUE_MSAT;
  94 use crate::offers::invoice_request::{DerivedPayerId, ExplicitPayerId, InvoiceRequestBuilder};
  95 use crate::offers::merkle::TlvStream;
  96 use crate::offers::parse::{Bech32Encode, Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
  97 use crate::offers::signer::{Metadata, MetadataMaterial, self};
  98 use crate::util::ser::{HighZeroBytesDroppedBigSize, WithoutLength, Writeable, Writer};
  99 use crate::util::string::PrintableString;
 100
 101 use crate::prelude::*;
 102
 103 #[cfg(feature = "std")]
 104 use std::time::SystemTime;
 105
 106 pub(super) const IV_BYTES: &[u8; IV_LEN] = b"LDK Offer ~~~~~~";
 107
 108 /// Builds an [`Offer`] for the "offer to be paid" flow.
 109 ///
 110 /// See [module-level documentation] for usage.
 111 ///
 112 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 113 ///
 114 /// [module-level documentation]: self
 115 pub struct OfferBuilder<'a, M: MetadataStrategy, T: secp256k1::Signing> {
 116         offer: OfferContents,
 117         metadata_strategy: core::marker::PhantomData<M>,
 118         secp_ctx: Option<&'a Secp256k1<T>>,
 119 }
 120
 121 /// Indicates how [`Offer::metadata`] may be set.
 122 ///
 123 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 124 pub trait MetadataStrategy {}
 125
 126 /// [`Offer::metadata`] may be explicitly set or left empty.
 127 ///
 128 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 129 pub struct ExplicitMetadata {}
 130
 131 /// [`Offer::metadata`] will be derived.
 132 ///
 133 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 134 pub struct DerivedMetadata {}
 135
 136 impl MetadataStrategy for ExplicitMetadata {}
 137 impl MetadataStrategy for DerivedMetadata {}
 138
 139 impl<'a> OfferBuilder<'a, ExplicitMetadata, secp256k1::SignOnly> {
 140         /// Creates a new builder for an offer setting the [`Offer::description`] and using the
 141         /// [`Offer::signing_pubkey`] for signing invoices. The associated secret key must be remembered
 142         /// while the offer is valid.
 143         ///
 144         /// Use a different pubkey per offer to avoid correlating offers.
 145         ///
 146         /// # Note
 147         ///
 148         /// If constructing an [`Offer`] for use with a [`ChannelManager`], use
 149         /// [`ChannelManager::create_offer_builder`] instead of [`OfferBuilder::new`].
 150         ///
 151         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 152         /// [`ChannelManager::create_offer_builder`]: crate::ln::channelmanager::ChannelManager::create_offer_builder
 153         pub fn new(description: String, signing_pubkey: PublicKey) -> Self {
 154                 OfferBuilder {
 155                         offer: OfferContents {
 156                                 chains: None, metadata: None, amount: None, description,
 157                                 features: OfferFeatures::empty(), absolute_expiry: None, issuer: None, paths: None,
 158                                 supported_quantity: Quantity::One, signing_pubkey,
 159                         },
 160                         metadata_strategy: core::marker::PhantomData,
 161                         secp_ctx: None,
 162                 }
 163         }
 164
 165         /// Sets the [`Offer::metadata`] to the given bytes.
 166         ///
 167         /// Successive calls to this method will override the previous setting.
 168         pub fn metadata(mut self, metadata: Vec<u8>) -> Result<Self, Bolt12SemanticError> {
 169                 self.offer.metadata = Some(Metadata::Bytes(metadata));
 170                 Ok(self)
 171         }
 172 }
 173
 174 impl<'a, T: secp256k1::Signing> OfferBuilder<'a, DerivedMetadata, T> {
 175         /// Similar to [`OfferBuilder::new`] except, if [`OfferBuilder::path`] is called, the signing
 176         /// pubkey is derived from the given [`ExpandedKey`] and [`EntropySource`]. This provides
 177         /// recipient privacy by using a different signing pubkey for each offer. Otherwise, the
 178         /// provided `node_id` is used for the signing pubkey.
 179         ///
 180         /// Also, sets the metadata when [`OfferBuilder::build`] is called such that it can be used by
 181         /// [`InvoiceRequest::verify`] to determine if the request was produced for the offer given an
 182         /// [`ExpandedKey`].
 183         ///
 184         /// [`InvoiceRequest::verify`]: crate::offers::invoice_request::InvoiceRequest::verify
 185         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 186         pub fn deriving_signing_pubkey<ES: Deref>(
 187                 description: String, node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 188                 secp_ctx: &'a Secp256k1<T>
 189         ) -> Self where ES::Target: EntropySource {
 190                 let nonce = Nonce::from_entropy_source(entropy_source);
 191                 let derivation_material = MetadataMaterial::new(nonce, expanded_key, IV_BYTES, None);
 192                 let metadata = Metadata::DerivedSigningPubkey(derivation_material);
 193                 OfferBuilder {
 194                         offer: OfferContents {
 195                                 chains: None, metadata: Some(metadata), amount: None, description,
 196                                 features: OfferFeatures::empty(), absolute_expiry: None, issuer: None, paths: None,
 197                                 supported_quantity: Quantity::One, signing_pubkey: node_id,
 198                         },
 199                         metadata_strategy: core::marker::PhantomData,
 200                         secp_ctx: Some(secp_ctx),
 201                 }
 202         }
 203 }
 204
 205 impl<'a, M: MetadataStrategy, T: secp256k1::Signing> OfferBuilder<'a, M, T> {
 206         /// Adds the chain hash of the given [`Network`] to [`Offer::chains`]. If not called,
 207         /// the chain hash of [`Network::Bitcoin`] is assumed to be the only one supported.
 208         ///
 209         /// See [`Offer::chains`] on how this relates to the payment currency.
 210         ///
 211         /// Successive calls to this method will add another chain hash.
 212         pub fn chain(self, network: Network) -> Self {
 213                 self.chain_hash(ChainHash::using_genesis_block(network))
 214         }
 215
 216         /// Adds the [`ChainHash`] to [`Offer::chains`]. If not called, the chain hash of
 217         /// [`Network::Bitcoin`] is assumed to be the only one supported.
 218         ///
 219         /// See [`Offer::chains`] on how this relates to the payment currency.
 220         ///
 221         /// Successive calls to this method will add another chain hash.
 222         pub(crate) fn chain_hash(mut self, chain: ChainHash) -> Self {
 223                 let chains = self.offer.chains.get_or_insert_with(Vec::new);
 224                 if !chains.contains(&chain) {
 225                         chains.push(chain);
 226                 }
 227
 228                 self
 229         }
 230
 231         /// Sets the [`Offer::amount`] as an [`Amount::Bitcoin`].
 232         ///
 233         /// Successive calls to this method will override the previous setting.
 234         pub fn amount_msats(self, amount_msats: u64) -> Self {
 235                 self.amount(Amount::Bitcoin { amount_msats })
 236         }
 237
 238         /// Sets the [`Offer::amount`].
 239         ///
 240         /// Successive calls to this method will override the previous setting.
 241         pub(super) fn amount(mut self, amount: Amount) -> Self {
 242                 self.offer.amount = Some(amount);
 243                 self
 244         }
 245
 246         /// Sets the [`Offer::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
 247         /// already passed is valid and can be checked for using [`Offer::is_expired`].
 248         ///
 249         /// Successive calls to this method will override the previous setting.
 250         pub fn absolute_expiry(mut self, absolute_expiry: Duration) -> Self {
 251                 self.offer.absolute_expiry = Some(absolute_expiry);
 252                 self
 253         }
 254
 255         /// Sets the [`Offer::issuer`].
 256         ///
 257         /// Successive calls to this method will override the previous setting.
 258         pub fn issuer(mut self, issuer: String) -> Self {
 259                 self.offer.issuer = Some(issuer);
 260                 self
 261         }
 262
 263         /// Adds a blinded path to [`Offer::paths`]. Must include at least one path if only connected by
 264         /// private channels or if [`Offer::signing_pubkey`] is not a public node id.
 265         ///
 266         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 267         /// adding duplicate paths.
 268         pub fn path(mut self, path: BlindedPath) -> Self {
 269                 self.offer.paths.get_or_insert_with(Vec::new).push(path);
 270                 self
 271         }
 272
 273         /// Sets the quantity of items for [`Offer::supported_quantity`]. If not called, defaults to
 274         /// [`Quantity::One`].
 275         ///
 276         /// Successive calls to this method will override the previous setting.
 277         pub fn supported_quantity(mut self, quantity: Quantity) -> Self {
 278                 self.offer.supported_quantity = quantity;
 279                 self
 280         }
 281
 282         /// Builds an [`Offer`] from the builder's settings.
 283         pub fn build(mut self) -> Result<Offer, Bolt12SemanticError> {
 284                 match self.offer.amount {
 285                         Some(Amount::Bitcoin { amount_msats }) => {
 286                                 if amount_msats > MAX_VALUE_MSAT {
 287                                         return Err(Bolt12SemanticError::InvalidAmount);
 288                                 }
 289                         },
 290                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 291                         None => {},
 292                 }
 293
 294                 if let Some(chains) = &self.offer.chains {
 295                         if chains.len() == 1 && chains[0] == self.offer.implied_chain() {
 296                                 self.offer.chains = None;
 297                         }
 298                 }
 299
 300                 Ok(self.build_without_checks())
 301         }
 302
 303         fn build_without_checks(mut self) -> Offer {
 304                 // Create the metadata for stateless verification of an InvoiceRequest.
 305                 if let Some(mut metadata) = self.offer.metadata.take() {
 306                         if metadata.has_derivation_material() {
 307                                 if self.offer.paths.is_none() {
 308                                         metadata = metadata.without_keys();
 309                                 }
 310
 311                                 let mut tlv_stream = self.offer.as_tlv_stream();
 312                                 debug_assert_eq!(tlv_stream.metadata, None);
 313                                 tlv_stream.metadata = None;
 314                                 if metadata.derives_recipient_keys() {
 315                                         tlv_stream.node_id = None;
 316                                 }
 317
 318                                 let (derived_metadata, keys) = metadata.derive_from(tlv_stream, self.secp_ctx);
 319                                 metadata = derived_metadata;
 320                                 if let Some(keys) = keys {
 321                                         self.offer.signing_pubkey = keys.public_key();
 322                                 }
 323                         }
 324
 325                         self.offer.metadata = Some(metadata);
 326                 }
 327
 328                 let mut bytes = Vec::new();
 329                 self.offer.write(&mut bytes).unwrap();
 330
 331                 Offer { bytes, contents: self.offer }
 332         }
 333 }
 334
 335 #[cfg(test)]
 336 impl<'a, M: MetadataStrategy, T: secp256k1::Signing> OfferBuilder<'a, M, T> {
 337         fn features_unchecked(mut self, features: OfferFeatures) -> Self {
 338                 self.offer.features = features;
 339                 self
 340         }
 341
 342         pub(super) fn build_unchecked(self) -> Offer {
 343                 self.build_without_checks()
 344         }
 345 }
 346
 347 /// An `Offer` is a potentially long-lived proposal for payment of a good or service.
 348 ///
 349 /// An offer is a precursor to an [`InvoiceRequest`]. A merchant publishes an offer from which a
 350 /// customer may request an [`Bolt12Invoice`] for a specific quantity and using an amount sufficient
 351 /// to cover that quantity (i.e., at least `quantity * amount`). See [`Offer::amount`].
 352 ///
 353 /// Offers may be denominated in currency other than bitcoin but are ultimately paid using the
 354 /// latter.
 355 ///
 356 /// Through the use of [`BlindedPath`]s, offers provide recipient privacy.
 357 ///
 358 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 359 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 360 #[derive(Clone, Debug)]
 361 #[cfg_attr(test, derive(PartialEq))]
 362 pub struct Offer {
 363         // The serialized offer. Needed when creating an `InvoiceRequest` if the offer contains unknown
 364         // fields.
 365         pub(super) bytes: Vec<u8>,
 366         pub(super) contents: OfferContents,
 367 }
 368
 369 /// The contents of an [`Offer`], which may be shared with an [`InvoiceRequest`] or a
 370 /// [`Bolt12Invoice`].
 371 ///
 372 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 373 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 374 #[derive(Clone, Debug)]
 375 #[cfg_attr(test, derive(PartialEq))]
 376 pub(super) struct OfferContents {
 377         chains: Option<Vec<ChainHash>>,
 378         metadata: Option<Metadata>,
 379         amount: Option<Amount>,
 380         description: String,
 381         features: OfferFeatures,
 382         absolute_expiry: Option<Duration>,
 383         issuer: Option<String>,
 384         paths: Option<Vec<BlindedPath>>,
 385         supported_quantity: Quantity,
 386         signing_pubkey: PublicKey,
 387 }
 388
 389 macro_rules! offer_accessors { ($self: ident, $contents: expr) => {
 390         // TODO: Return a slice once ChainHash has constants.
 391         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1283
 392         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1286
 393         /// The chains that may be used when paying a requested invoice (e.g., bitcoin mainnet).
 394         /// Payments must be denominated in units of the minimal lightning-payable unit (e.g., msats)
 395         /// for the selected chain.
 396         pub fn chains(&$self) -> Vec<bitcoin::blockdata::constants::ChainHash> {
 397                 $contents.chains()
 398         }
 399
 400         // TODO: Link to corresponding method in `InvoiceRequest`.
 401         /// Opaque bytes set by the originator. Useful for authentication and validating fields since it
 402         /// is reflected in `invoice_request` messages along with all the other fields from the `offer`.
 403         pub fn metadata(&$self) -> Option<&Vec<u8>> {
 404                 $contents.metadata()
 405         }
 406
 407         /// The minimum amount required for a successful payment of a single item.
 408         pub fn amount(&$self) -> Option<&$crate::offers::offer::Amount> {
 409                 $contents.amount()
 410         }
 411
 412         /// A complete description of the purpose of the payment. Intended to be displayed to the user
 413         /// but with the caveat that it has not been verified in any way.
 414         pub fn description(&$self) -> $crate::util::string::PrintableString {
 415                 $contents.description()
 416         }
 417
 418         /// Features pertaining to the offer.
 419         pub fn offer_features(&$self) -> &$crate::ln::features::OfferFeatures {
 420                 &$contents.features()
 421         }
 422
 423         /// Duration since the Unix epoch when an invoice should no longer be requested.
 424         ///
 425         /// If `None`, the offer does not expire.
 426         pub fn absolute_expiry(&$self) -> Option<core::time::Duration> {
 427                 $contents.absolute_expiry()
 428         }
 429
 430         /// The issuer of the offer, possibly beginning with `user@domain` or `domain`. Intended to be
 431         /// displayed to the user but with the caveat that it has not been verified in any way.
 432         pub fn issuer(&$self) -> Option<$crate::util::string::PrintableString> {
 433                 $contents.issuer()
 434         }
 435
 436         /// Paths to the recipient originating from publicly reachable nodes. Blinded paths provide
 437         /// recipient privacy by obfuscating its node id.
 438         pub fn paths(&$self) -> &[$crate::blinded_path::BlindedPath] {
 439                 $contents.paths()
 440         }
 441
 442         /// The quantity of items supported.
 443         pub fn supported_quantity(&$self) -> $crate::offers::offer::Quantity {
 444                 $contents.supported_quantity()
 445         }
 446
 447         /// The public key used by the recipient to sign invoices.
 448         pub fn signing_pubkey(&$self) -> bitcoin::secp256k1::PublicKey {
 449                 $contents.signing_pubkey()
 450         }
 451 } }
 452
 453 impl Offer {
 454         offer_accessors!(self, self.contents);
 455
 456         pub(super) fn implied_chain(&self) -> ChainHash {
 457                 self.contents.implied_chain()
 458         }
 459
 460         /// Returns whether the given chain is supported by the offer.
 461         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 462                 self.contents.supports_chain(chain)
 463         }
 464
 465         /// Whether the offer has expired.
 466         #[cfg(feature = "std")]
 467         pub fn is_expired(&self) -> bool {
 468                 self.contents.is_expired()
 469         }
 470
 471         /// Whether the offer has expired given the duration since the Unix epoch.
 472         pub fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 473                 self.contents.is_expired_no_std(duration_since_epoch)
 474         }
 475
 476         /// Returns whether the given quantity is valid for the offer.
 477         pub fn is_valid_quantity(&self, quantity: u64) -> bool {
 478                 self.contents.is_valid_quantity(quantity)
 479         }
 480
 481         /// Returns whether a quantity is expected in an [`InvoiceRequest`] for the offer.
 482         ///
 483         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 484         pub fn expects_quantity(&self) -> bool {
 485                 self.contents.expects_quantity()
 486         }
 487
 488         /// Similar to [`Offer::request_invoice`] except it:
 489         /// - derives the [`InvoiceRequest::payer_id`] such that a different key can be used for each
 490         ///   request,
 491         /// - sets [`InvoiceRequest::payer_metadata`] when [`InvoiceRequestBuilder::build`] is called
 492         ///   such that it can be used by [`Bolt12Invoice::verify`] to determine if the invoice was
 493         ///   requested using a base [`ExpandedKey`] from which the payer id was derived, and
 494         /// - includes the [`PaymentId`] encrypted in [`InvoiceRequest::payer_metadata`] so that it can
 495         ///   be used when sending the payment for the requested invoice.
 496         ///
 497         /// Useful to protect the sender's privacy.
 498         ///
 499         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 500         ///
 501         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 502         /// [`InvoiceRequest::payer_metadata`]: crate::offers::invoice_request::InvoiceRequest::payer_metadata
 503         /// [`Bolt12Invoice::verify`]: crate::offers::invoice::Bolt12Invoice::verify
 504         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 505         pub fn request_invoice_deriving_payer_id<'a, 'b, ES: Deref, T: secp256k1::Signing>(
 506                 &'a self, expanded_key: &ExpandedKey, entropy_source: ES, secp_ctx: &'b Secp256k1<T>,
 507                 payment_id: PaymentId
 508         ) -> Result<InvoiceRequestBuilder<'a, 'b, DerivedPayerId, T>, Bolt12SemanticError>
 509         where
 510                 ES::Target: EntropySource,
 511         {
 512                 if self.offer_features().requires_unknown_bits() {
 513                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 514                 }
 515
 516                 Ok(InvoiceRequestBuilder::deriving_payer_id(
 517                         self, expanded_key, entropy_source, secp_ctx, payment_id
 518                 ))
 519         }
 520
 521         /// Similar to [`Offer::request_invoice_deriving_payer_id`] except uses `payer_id` for the
 522         /// [`InvoiceRequest::payer_id`] instead of deriving a different key for each request.
 523         ///
 524         /// Useful for recurring payments using the same `payer_id` with different invoices.
 525         ///
 526         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 527         ///
 528         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 529         pub fn request_invoice_deriving_metadata<ES: Deref>(
 530                 &self, payer_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 531                 payment_id: PaymentId
 532         ) -> Result<InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>, Bolt12SemanticError>
 533         where
 534                 ES::Target: EntropySource,
 535         {
 536                 if self.offer_features().requires_unknown_bits() {
 537                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 538                 }
 539
 540                 Ok(InvoiceRequestBuilder::deriving_metadata(
 541                         self, payer_id, expanded_key, entropy_source, payment_id
 542                 ))
 543         }
 544
 545         /// Creates an [`InvoiceRequestBuilder`] for the offer with the given `metadata` and `payer_id`,
 546         /// which will be reflected in the `Bolt12Invoice` response.
 547         ///
 548         /// The `metadata` is useful for including information about the derivation of `payer_id` such
 549         /// that invoice response handling can be stateless. Also serves as payer-provided entropy while
 550         /// hashing in the signature calculation.
 551         ///
 552         /// This should not leak any information such as by using a simple BIP-32 derivation path.
 553         /// Otherwise, payments may be correlated.
 554         ///
 555         /// Errors if the offer contains unknown required features.
 556         ///
 557         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 558         ///
 559         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 560         pub fn request_invoice(
 561                 &self, metadata: Vec<u8>, payer_id: PublicKey
 562         ) -> Result<InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>, Bolt12SemanticError> {
 563                 if self.offer_features().requires_unknown_bits() {
 564                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 565                 }
 566
 567                 Ok(InvoiceRequestBuilder::new(self, metadata, payer_id))
 568         }
 569
 570         #[cfg(test)]
 571         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 572                 self.contents.as_tlv_stream()
 573         }
 574 }
 575
 576 impl AsRef<[u8]> for Offer {
 577         fn as_ref(&self) -> &[u8] {
 578                 &self.bytes
 579         }
 580 }
 581
 582 impl OfferContents {
 583         pub fn chains(&self) -> Vec<ChainHash> {
 584                 self.chains.as_ref().cloned().unwrap_or_else(|| vec![self.implied_chain()])
 585         }
 586
 587         pub fn implied_chain(&self) -> ChainHash {
 588                 ChainHash::using_genesis_block(Network::Bitcoin)
 589         }
 590
 591         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 592                 self.chains().contains(&chain)
 593         }
 594
 595         pub fn metadata(&self) -> Option<&Vec<u8>> {
 596                 self.metadata.as_ref().and_then(|metadata| metadata.as_bytes())
 597         }
 598
 599         pub fn amount(&self) -> Option<&Amount> {
 600                 self.amount.as_ref()
 601         }
 602
 603         pub fn description(&self) -> PrintableString {
 604                 PrintableString(&self.description)
 605         }
 606
 607         pub fn features(&self) -> &OfferFeatures {
 608                 &self.features
 609         }
 610
 611         pub fn absolute_expiry(&self) -> Option<Duration> {
 612                 self.absolute_expiry
 613         }
 614
 615         #[cfg(feature = "std")]
 616         pub(super) fn is_expired(&self) -> bool {
 617                 SystemTime::UNIX_EPOCH
 618                         .elapsed()
 619                         .map(|duration_since_epoch| self.is_expired_no_std(duration_since_epoch))
 620                         .unwrap_or(false)
 621         }
 622
 623         pub(super) fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 624                 self.absolute_expiry
 625                         .map(|absolute_expiry| duration_since_epoch > absolute_expiry)
 626                         .unwrap_or(false)
 627         }
 628
 629         pub fn issuer(&self) -> Option<PrintableString> {
 630                 self.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 631         }
 632
 633         pub fn paths(&self) -> &[BlindedPath] {
 634                 self.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 635         }
 636
 637         pub(super) fn check_amount_msats_for_quantity(
 638                 &self, amount_msats: Option<u64>, quantity: Option<u64>
 639         ) -> Result<(), Bolt12SemanticError> {
 640                 let offer_amount_msats = match self.amount {
 641                         None => 0,
 642                         Some(Amount::Bitcoin { amount_msats }) => amount_msats,
 643                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 644                 };
 645
 646                 if !self.expects_quantity() || quantity.is_some() {
 647                         let expected_amount_msats = offer_amount_msats.checked_mul(quantity.unwrap_or(1))
 648                                 .ok_or(Bolt12SemanticError::InvalidAmount)?;
 649                         let amount_msats = amount_msats.unwrap_or(expected_amount_msats);
 650
 651                         if amount_msats < expected_amount_msats {
 652                                 return Err(Bolt12SemanticError::InsufficientAmount);
 653                         }
 654
 655                         if amount_msats > MAX_VALUE_MSAT {
 656                                 return Err(Bolt12SemanticError::InvalidAmount);
 657                         }
 658                 }
 659
 660                 Ok(())
 661         }
 662
 663         pub fn supported_quantity(&self) -> Quantity {
 664                 self.supported_quantity
 665         }
 666
 667         pub(super) fn check_quantity(&self, quantity: Option<u64>) -> Result<(), Bolt12SemanticError> {
 668                 let expects_quantity = self.expects_quantity();
 669                 match quantity {
 670                         None if expects_quantity => Err(Bolt12SemanticError::MissingQuantity),
 671                         Some(_) if !expects_quantity => Err(Bolt12SemanticError::UnexpectedQuantity),
 672                         Some(quantity) if !self.is_valid_quantity(quantity) => {
 673                                 Err(Bolt12SemanticError::InvalidQuantity)
 674                         },
 675                         _ => Ok(()),
 676                 }
 677         }
 678
 679         fn is_valid_quantity(&self, quantity: u64) -> bool {
 680                 match self.supported_quantity {
 681                         Quantity::Bounded(n) => quantity <= n.get(),
 682                         Quantity::Unbounded => quantity > 0,
 683                         Quantity::One => quantity == 1,
 684                 }
 685         }
 686
 687         fn expects_quantity(&self) -> bool {
 688                 match self.supported_quantity {
 689                         Quantity::Bounded(_) => true,
 690                         Quantity::Unbounded => true,
 691                         Quantity::One => false,
 692                 }
 693         }
 694
 695         pub(super) fn signing_pubkey(&self) -> PublicKey {
 696                 self.signing_pubkey
 697         }
 698
 699         /// Verifies that the offer metadata was produced from the offer in the TLV stream.
 700         pub(super) fn verify<T: secp256k1::Signing>(
 701                 &self, bytes: &[u8], key: &ExpandedKey, secp_ctx: &Secp256k1<T>
 702         ) -> Result<Option<KeyPair>, ()> {
 703                 match self.metadata() {
 704                         Some(metadata) => {
 705                                 let tlv_stream = TlvStream::new(bytes).range(OFFER_TYPES).filter(|record| {
 706                                         match record.r#type {
 707                                                 OFFER_METADATA_TYPE => false,
 708                                                 OFFER_NODE_ID_TYPE => {
 709                                                         !self.metadata.as_ref().unwrap().derives_recipient_keys()
 710                                                 },
 711                                                 _ => true,
 712                                         }
 713                                 });
 714                                 signer::verify_recipient_metadata(
 715                                         metadata, key, IV_BYTES, self.signing_pubkey(), tlv_stream, secp_ctx
 716                                 )
 717                         },
 718                         None => Err(()),
 719                 }
 720         }
 721
 722         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 723                 let (currency, amount) = match &self.amount {
 724                         None => (None, None),
 725                         Some(Amount::Bitcoin { amount_msats }) => (None, Some(*amount_msats)),
 726                         Some(Amount::Currency { iso4217_code, amount }) => (
 727                                 Some(iso4217_code), Some(*amount)
 728                         ),
 729                 };
 730
 731                 let features = {
 732                         if self.features == OfferFeatures::empty() { None } else { Some(&self.features) }
 733                 };
 734
 735                 OfferTlvStreamRef {
 736                         chains: self.chains.as_ref(),
 737                         metadata: self.metadata(),
 738                         currency,
 739                         amount,
 740                         description: Some(&self.description),
 741                         features,
 742                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 743                         paths: self.paths.as_ref(),
 744                         issuer: self.issuer.as_ref(),
 745                         quantity_max: self.supported_quantity.to_tlv_record(),
 746                         node_id: Some(&self.signing_pubkey),
 747                 }
 748         }
 749 }
 750
 751 impl Writeable for Offer {
 752         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 753                 WithoutLength(&self.bytes).write(writer)
 754         }
 755 }
 756
 757 impl Writeable for OfferContents {
 758         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 759                 self.as_tlv_stream().write(writer)
 760         }
 761 }
 762
 763 /// The minimum amount required for an item in an [`Offer`], denominated in either bitcoin or
 764 /// another currency.
 765 #[derive(Clone, Debug, PartialEq)]
 766 pub enum Amount {
 767         /// An amount of bitcoin.
 768         Bitcoin {
 769                 /// The amount in millisatoshi.
 770                 amount_msats: u64,
 771         },
 772         /// An amount of currency specified using ISO 4712.
 773         Currency {
 774                 /// The currency that the amount is denominated in.
 775                 iso4217_code: CurrencyCode,
 776                 /// The amount in the currency unit adjusted by the ISO 4712 exponent (e.g., USD cents).
 777                 amount: u64,
 778         },
 779 }
 780
 781 /// An ISO 4712 three-letter currency code (e.g., USD).
 782 pub type CurrencyCode = [u8; 3];
 783
 784 /// Quantity of items supported by an [`Offer`].
 785 #[derive(Clone, Copy, Debug, PartialEq)]
 786 pub enum Quantity {
 787         /// Up to a specific number of items (inclusive). Use when more than one item can be requested
 788         /// but is limited (e.g., because of per customer or inventory limits).
 789         ///
 790         /// May be used with `NonZeroU64::new(1)` but prefer to use [`Quantity::One`] if only one item
 791         /// is supported.
 792         Bounded(NonZeroU64),
 793         /// One or more items. Use when more than one item can be requested without any limit.
 794         Unbounded,
 795         /// Only one item. Use when only a single item can be requested.
 796         One,
 797 }
 798
 799 impl Quantity {
 800         fn to_tlv_record(&self) -> Option<u64> {
 801                 match self {
 802                         Quantity::Bounded(n) => Some(n.get()),
 803                         Quantity::Unbounded => Some(0),
 804                         Quantity::One => None,
 805                 }
 806         }
 807 }
 808
 809 /// Valid type range for offer TLV records.
 810 pub(super) const OFFER_TYPES: core::ops::Range<u64> = 1..80;
 811
 812 /// TLV record type for [`Offer::metadata`].
 813 const OFFER_METADATA_TYPE: u64 = 4;
 814
 815 /// TLV record type for [`Offer::signing_pubkey`].
 816 const OFFER_NODE_ID_TYPE: u64 = 22;
 817
 818 tlv_stream!(OfferTlvStream, OfferTlvStreamRef, OFFER_TYPES, {
 819         (2, chains: (Vec<ChainHash>, WithoutLength)),
 820         (OFFER_METADATA_TYPE, metadata: (Vec<u8>, WithoutLength)),
 821         (6, currency: CurrencyCode),
 822         (8, amount: (u64, HighZeroBytesDroppedBigSize)),
 823         (10, description: (String, WithoutLength)),
 824         (12, features: (OfferFeatures, WithoutLength)),
 825         (14, absolute_expiry: (u64, HighZeroBytesDroppedBigSize)),
 826         (16, paths: (Vec<BlindedPath>, WithoutLength)),
 827         (18, issuer: (String, WithoutLength)),
 828         (20, quantity_max: (u64, HighZeroBytesDroppedBigSize)),
 829         (OFFER_NODE_ID_TYPE, node_id: PublicKey),
 830 });
 831
 832 impl Bech32Encode for Offer {
 833         const BECH32_HRP: &'static str = "lno";
 834 }
 835
 836 impl FromStr for Offer {
 837         type Err = Bolt12ParseError;
 838
 839         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 840                 Self::from_bech32_str(s)
 841         }
 842 }
 843
 844 impl TryFrom<Vec<u8>> for Offer {
 845         type Error = Bolt12ParseError;
 846
 847         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 848                 let offer = ParsedMessage::<OfferTlvStream>::try_from(bytes)?;
 849                 let ParsedMessage { bytes, tlv_stream } = offer;
 850                 let contents = OfferContents::try_from(tlv_stream)?;
 851                 Ok(Offer { bytes, contents })
 852         }
 853 }
 854
 855 impl TryFrom<OfferTlvStream> for OfferContents {
 856         type Error = Bolt12SemanticError;
 857
 858         fn try_from(tlv_stream: OfferTlvStream) -> Result<Self, Self::Error> {
 859                 let OfferTlvStream {
 860                         chains, metadata, currency, amount, description, features, absolute_expiry, paths,
 861                         issuer, quantity_max, node_id,
 862                 } = tlv_stream;
 863
 864                 let metadata = metadata.map(|metadata| Metadata::Bytes(metadata));
 865
 866                 let amount = match (currency, amount) {
 867                         (None, None) => None,
 868                         (None, Some(amount_msats)) if amount_msats > MAX_VALUE_MSAT => {
 869                                 return Err(Bolt12SemanticError::InvalidAmount);
 870                         },
 871                         (None, Some(amount_msats)) => Some(Amount::Bitcoin { amount_msats }),
 872                         (Some(_), None) => return Err(Bolt12SemanticError::MissingAmount),
 873                         (Some(iso4217_code), Some(amount)) => Some(Amount::Currency { iso4217_code, amount }),
 874                 };
 875
 876                 let description = match description {
 877                         None => return Err(Bolt12SemanticError::MissingDescription),
 878                         Some(description) => description,
 879                 };
 880
 881                 let features = features.unwrap_or_else(OfferFeatures::empty);
 882
 883                 let absolute_expiry = absolute_expiry
 884                         .map(|seconds_from_epoch| Duration::from_secs(seconds_from_epoch));
 885
 886                 let supported_quantity = match quantity_max {
 887                         None => Quantity::One,
 888                         Some(0) => Quantity::Unbounded,
 889                         Some(n) => Quantity::Bounded(NonZeroU64::new(n).unwrap()),
 890                 };
 891
 892                 let signing_pubkey = match node_id {
 893                         None => return Err(Bolt12SemanticError::MissingSigningPubkey),
 894                         Some(node_id) => node_id,
 895                 };
 896
 897                 Ok(OfferContents {
 898                         chains, metadata, amount, description, features, absolute_expiry, issuer, paths,
 899                         supported_quantity, signing_pubkey,
 900                 })
 901         }
 902 }
 903
 904 impl core::fmt::Display for Offer {
 905         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 906                 self.fmt_bech32_str(f)
 907         }
 908 }
 909
 910 #[cfg(test)]
 911 mod tests {
 912         use super::{Amount, Offer, OfferBuilder, OfferTlvStreamRef, Quantity};
 913
 914         use bitcoin::blockdata::constants::ChainHash;
 915         use bitcoin::network::constants::Network;
 916         use bitcoin::secp256k1::Secp256k1;
 917         use core::convert::TryFrom;
 918         use core::num::NonZeroU64;
 919         use core::time::Duration;
 920         use crate::blinded_path::{BlindedHop, BlindedPath};
 921         use crate::sign::KeyMaterial;
 922         use crate::ln::features::OfferFeatures;
 923         use crate::ln::inbound_payment::ExpandedKey;
 924         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 925         use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
 926         use crate::offers::test_utils::*;
 927         use crate::util::ser::{BigSize, Writeable};
 928         use crate::util::string::PrintableString;
 929
 930         #[test]
 931         fn builds_offer_with_defaults() {
 932                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
 933
 934                 let mut buffer = Vec::new();
 935                 offer.write(&mut buffer).unwrap();
 936
 937                 assert_eq!(offer.bytes, buffer.as_slice());
 938                 assert_eq!(offer.chains(), vec![ChainHash::using_genesis_block(Network::Bitcoin)]);
 939                 assert!(offer.supports_chain(ChainHash::using_genesis_block(Network::Bitcoin)));
 940                 assert_eq!(offer.metadata(), None);
 941                 assert_eq!(offer.amount(), None);
 942                 assert_eq!(offer.description(), PrintableString("foo"));
 943                 assert_eq!(offer.offer_features(), &OfferFeatures::empty());
 944                 assert_eq!(offer.absolute_expiry(), None);
 945                 #[cfg(feature = "std")]
 946                 assert!(!offer.is_expired());
 947                 assert_eq!(offer.paths(), &[]);
 948                 assert_eq!(offer.issuer(), None);
 949                 assert_eq!(offer.supported_quantity(), Quantity::One);
 950                 assert_eq!(offer.signing_pubkey(), pubkey(42));
 951
 952                 assert_eq!(
 953                         offer.as_tlv_stream(),
 954                         OfferTlvStreamRef {
 955                                 chains: None,
 956                                 metadata: None,
 957                                 currency: None,
 958                                 amount: None,
 959                                 description: Some(&String::from("foo")),
 960                                 features: None,
 961                                 absolute_expiry: None,
 962                                 paths: None,
 963                                 issuer: None,
 964                                 quantity_max: None,
 965                                 node_id: Some(&pubkey(42)),
 966                         },
 967                 );
 968
 969                 if let Err(e) = Offer::try_from(buffer) {
 970                         panic!("error parsing offer: {:?}", e);
 971                 }
 972         }
 973
 974         #[test]
 975         fn builds_offer_with_chains() {
 976                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
 977                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
 978
 979                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 980                         .chain(Network::Bitcoin)
 981                         .build()
 982                         .unwrap();
 983                 assert!(offer.supports_chain(mainnet));
 984                 assert_eq!(offer.chains(), vec![mainnet]);
 985                 assert_eq!(offer.as_tlv_stream().chains, None);
 986
 987                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 988                         .chain(Network::Testnet)
 989                         .build()
 990                         .unwrap();
 991                 assert!(offer.supports_chain(testnet));
 992                 assert_eq!(offer.chains(), vec![testnet]);
 993                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 994
 995                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 996                         .chain(Network::Testnet)
 997                         .chain(Network::Testnet)
 998                         .build()
 999                         .unwrap();
1000                 assert!(offer.supports_chain(testnet));
1001                 assert_eq!(offer.chains(), vec![testnet]);
1002                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
1003
1004                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1005                         .chain(Network::Bitcoin)
1006                         .chain(Network::Testnet)
1007                         .build()
1008                         .unwrap();
1009                 assert!(offer.supports_chain(mainnet));
1010                 assert!(offer.supports_chain(testnet));
1011                 assert_eq!(offer.chains(), vec![mainnet, testnet]);
1012                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![mainnet, testnet]));
1013         }
1014
1015         #[test]
1016         fn builds_offer_with_metadata() {
1017                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1018                         .metadata(vec![42; 32]).unwrap()
1019                         .build()
1020                         .unwrap();
1021                 assert_eq!(offer.metadata(), Some(&vec![42; 32]));
1022                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![42; 32]));
1023
1024                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1025                         .metadata(vec![42; 32]).unwrap()
1026                         .metadata(vec![43; 32]).unwrap()
1027                         .build()
1028                         .unwrap();
1029                 assert_eq!(offer.metadata(), Some(&vec![43; 32]));
1030                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![43; 32]));
1031         }
1032
1033         #[test]
1034         fn builds_offer_with_metadata_derived() {
1035                 let desc = "foo".to_string();
1036                 let node_id = recipient_pubkey();
1037                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1038                 let entropy = FixedEntropy {};
1039                 let secp_ctx = Secp256k1::new();
1040
1041                 let offer = OfferBuilder
1042                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
1043                         .amount_msats(1000)
1044                         .build().unwrap();
1045                 assert_eq!(offer.signing_pubkey(), node_id);
1046
1047                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1048                         .build().unwrap()
1049                         .sign(payer_sign).unwrap();
1050                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
1051
1052                 // Fails verification with altered offer field
1053                 let mut tlv_stream = offer.as_tlv_stream();
1054                 tlv_stream.amount = Some(100);
1055
1056                 let mut encoded_offer = Vec::new();
1057                 tlv_stream.write(&mut encoded_offer).unwrap();
1058
1059                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1060                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1061                         .build().unwrap()
1062                         .sign(payer_sign).unwrap();
1063                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1064
1065                 // Fails verification with altered metadata
1066                 let mut tlv_stream = offer.as_tlv_stream();
1067                 let metadata = tlv_stream.metadata.unwrap().iter().copied().rev().collect();
1068                 tlv_stream.metadata = Some(&metadata);
1069
1070                 let mut encoded_offer = Vec::new();
1071                 tlv_stream.write(&mut encoded_offer).unwrap();
1072
1073                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1074                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1075                         .build().unwrap()
1076                         .sign(payer_sign).unwrap();
1077                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1078         }
1079
1080         #[test]
1081         fn builds_offer_with_derived_signing_pubkey() {
1082                 let desc = "foo".to_string();
1083                 let node_id = recipient_pubkey();
1084                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1085                 let entropy = FixedEntropy {};
1086                 let secp_ctx = Secp256k1::new();
1087
1088                 let blinded_path = BlindedPath {
1089                         introduction_node_id: pubkey(40),
1090                         blinding_point: pubkey(41),
1091                         blinded_hops: vec![
1092                                 BlindedHop { blinded_node_id: pubkey(42), encrypted_payload: vec![0; 43] },
1093                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
1094                         ],
1095                 };
1096
1097                 let offer = OfferBuilder
1098                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
1099                         .amount_msats(1000)
1100                         .path(blinded_path)
1101                         .build().unwrap();
1102                 assert_ne!(offer.signing_pubkey(), node_id);
1103
1104                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1105                         .build().unwrap()
1106                         .sign(payer_sign).unwrap();
1107                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
1108
1109                 // Fails verification with altered offer field
1110                 let mut tlv_stream = offer.as_tlv_stream();
1111                 tlv_stream.amount = Some(100);
1112
1113                 let mut encoded_offer = Vec::new();
1114                 tlv_stream.write(&mut encoded_offer).unwrap();
1115
1116                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1117                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1118                         .build().unwrap()
1119                         .sign(payer_sign).unwrap();
1120                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1121
1122                 // Fails verification with altered signing pubkey
1123                 let mut tlv_stream = offer.as_tlv_stream();
1124                 let signing_pubkey = pubkey(1);
1125                 tlv_stream.node_id = Some(&signing_pubkey);
1126
1127                 let mut encoded_offer = Vec::new();
1128                 tlv_stream.write(&mut encoded_offer).unwrap();
1129
1130                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1131                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1132                         .build().unwrap()
1133                         .sign(payer_sign).unwrap();
1134                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1135         }
1136
1137         #[test]
1138         fn builds_offer_with_amount() {
1139                 let bitcoin_amount = Amount::Bitcoin { amount_msats: 1000 };
1140                 let currency_amount = Amount::Currency { iso4217_code: *b"USD", amount: 10 };
1141
1142                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1143                         .amount_msats(1000)
1144                         .build()
1145                         .unwrap();
1146                 let tlv_stream = offer.as_tlv_stream();
1147                 assert_eq!(offer.amount(), Some(&bitcoin_amount));
1148                 assert_eq!(tlv_stream.amount, Some(1000));
1149                 assert_eq!(tlv_stream.currency, None);
1150
1151                 let builder = OfferBuilder::new("foo".into(), pubkey(42))
1152                         .amount(currency_amount.clone());
1153                 let tlv_stream = builder.offer.as_tlv_stream();
1154                 assert_eq!(builder.offer.amount, Some(currency_amount.clone()));
1155                 assert_eq!(tlv_stream.amount, Some(10));
1156                 assert_eq!(tlv_stream.currency, Some(b"USD"));
1157                 match builder.build() {
1158                         Ok(_) => panic!("expected error"),
1159                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnsupportedCurrency),
1160                 }
1161
1162                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1163                         .amount(currency_amount.clone())
1164                         .amount(bitcoin_amount.clone())
1165                         .build()
1166                         .unwrap();
1167                 let tlv_stream = offer.as_tlv_stream();
1168                 assert_eq!(tlv_stream.amount, Some(1000));
1169                 assert_eq!(tlv_stream.currency, None);
1170
1171                 let invalid_amount = Amount::Bitcoin { amount_msats: MAX_VALUE_MSAT + 1 };
1172                 match OfferBuilder::new("foo".into(), pubkey(42)).amount(invalid_amount).build() {
1173                         Ok(_) => panic!("expected error"),
1174                         Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
1175                 }
1176         }
1177
1178         #[test]
1179         fn builds_offer_with_features() {
1180                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1181                         .features_unchecked(OfferFeatures::unknown())
1182                         .build()
1183                         .unwrap();
1184                 assert_eq!(offer.offer_features(), &OfferFeatures::unknown());
1185                 assert_eq!(offer.as_tlv_stream().features, Some(&OfferFeatures::unknown()));
1186
1187                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1188                         .features_unchecked(OfferFeatures::unknown())
1189                         .features_unchecked(OfferFeatures::empty())
1190                         .build()
1191                         .unwrap();
1192                 assert_eq!(offer.offer_features(), &OfferFeatures::empty());
1193                 assert_eq!(offer.as_tlv_stream().features, None);
1194         }
1195
1196         #[test]
1197         fn builds_offer_with_absolute_expiry() {
1198                 let future_expiry = Duration::from_secs(u64::max_value());
1199                 let past_expiry = Duration::from_secs(0);
1200                 let now = future_expiry - Duration::from_secs(1_000);
1201
1202                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1203                         .absolute_expiry(future_expiry)
1204                         .build()
1205                         .unwrap();
1206                 #[cfg(feature = "std")]
1207                 assert!(!offer.is_expired());
1208                 assert!(!offer.is_expired_no_std(now));
1209                 assert_eq!(offer.absolute_expiry(), Some(future_expiry));
1210                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(future_expiry.as_secs()));
1211
1212                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1213                         .absolute_expiry(future_expiry)
1214                         .absolute_expiry(past_expiry)
1215                         .build()
1216                         .unwrap();
1217                 #[cfg(feature = "std")]
1218                 assert!(offer.is_expired());
1219                 assert!(offer.is_expired_no_std(now));
1220                 assert_eq!(offer.absolute_expiry(), Some(past_expiry));
1221                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(past_expiry.as_secs()));
1222         }
1223
1224         #[test]
1225         fn builds_offer_with_paths() {
1226                 let paths = vec![
1227                         BlindedPath {
1228                                 introduction_node_id: pubkey(40),
1229                                 blinding_point: pubkey(41),
1230                                 blinded_hops: vec![
1231                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1232                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1233                                 ],
1234                         },
1235                         BlindedPath {
1236                                 introduction_node_id: pubkey(40),
1237                                 blinding_point: pubkey(41),
1238                                 blinded_hops: vec![
1239                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1240                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1241                                 ],
1242                         },
1243                 ];
1244
1245                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1246                         .path(paths[0].clone())
1247                         .path(paths[1].clone())
1248                         .build()
1249                         .unwrap();
1250                 let tlv_stream = offer.as_tlv_stream();
1251                 assert_eq!(offer.paths(), paths.as_slice());
1252                 assert_eq!(offer.signing_pubkey(), pubkey(42));
1253                 assert_ne!(pubkey(42), pubkey(44));
1254                 assert_eq!(tlv_stream.paths, Some(&paths));
1255                 assert_eq!(tlv_stream.node_id, Some(&pubkey(42)));
1256         }
1257
1258         #[test]
1259         fn builds_offer_with_issuer() {
1260                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1261                         .issuer("bar".into())
1262                         .build()
1263                         .unwrap();
1264                 assert_eq!(offer.issuer(), Some(PrintableString("bar")));
1265                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("bar")));
1266
1267                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1268                         .issuer("bar".into())
1269                         .issuer("baz".into())
1270                         .build()
1271                         .unwrap();
1272                 assert_eq!(offer.issuer(), Some(PrintableString("baz")));
1273                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("baz")));
1274         }
1275
1276         #[test]
1277         fn builds_offer_with_supported_quantity() {
1278                 let one = NonZeroU64::new(1).unwrap();
1279                 let ten = NonZeroU64::new(10).unwrap();
1280
1281                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1282                         .supported_quantity(Quantity::One)
1283                         .build()
1284                         .unwrap();
1285                 let tlv_stream = offer.as_tlv_stream();
1286                 assert_eq!(offer.supported_quantity(), Quantity::One);
1287                 assert_eq!(tlv_stream.quantity_max, None);
1288
1289                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1290                         .supported_quantity(Quantity::Unbounded)
1291                         .build()
1292                         .unwrap();
1293                 let tlv_stream = offer.as_tlv_stream();
1294                 assert_eq!(offer.supported_quantity(), Quantity::Unbounded);
1295                 assert_eq!(tlv_stream.quantity_max, Some(0));
1296
1297                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1298                         .supported_quantity(Quantity::Bounded(ten))
1299                         .build()
1300                         .unwrap();
1301                 let tlv_stream = offer.as_tlv_stream();
1302                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(ten));
1303                 assert_eq!(tlv_stream.quantity_max, Some(10));
1304
1305                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1306                         .supported_quantity(Quantity::Bounded(one))
1307                         .build()
1308                         .unwrap();
1309                 let tlv_stream = offer.as_tlv_stream();
1310                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(one));
1311                 assert_eq!(tlv_stream.quantity_max, Some(1));
1312
1313                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1314                         .supported_quantity(Quantity::Bounded(ten))
1315                         .supported_quantity(Quantity::One)
1316                         .build()
1317                         .unwrap();
1318                 let tlv_stream = offer.as_tlv_stream();
1319                 assert_eq!(offer.supported_quantity(), Quantity::One);
1320                 assert_eq!(tlv_stream.quantity_max, None);
1321         }
1322
1323         #[test]
1324         fn fails_requesting_invoice_with_unknown_required_features() {
1325                 match OfferBuilder::new("foo".into(), pubkey(42))
1326                         .features_unchecked(OfferFeatures::unknown())
1327                         .build().unwrap()
1328                         .request_invoice(vec![1; 32], pubkey(43))
1329                 {
1330                         Ok(_) => panic!("expected error"),
1331                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnknownRequiredFeatures),
1332                 }
1333         }
1334
1335         #[test]
1336         fn parses_offer_with_chains() {
1337                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1338                         .chain(Network::Bitcoin)
1339                         .chain(Network::Testnet)
1340                         .build()
1341                         .unwrap();
1342                 if let Err(e) = offer.to_string().parse::<Offer>() {
1343                         panic!("error parsing offer: {:?}", e);
1344                 }
1345         }
1346
1347         #[test]
1348         fn parses_offer_with_amount() {
1349                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1350                         .amount(Amount::Bitcoin { amount_msats: 1000 })
1351                         .build()
1352                         .unwrap();
1353                 if let Err(e) = offer.to_string().parse::<Offer>() {
1354                         panic!("error parsing offer: {:?}", e);
1355                 }
1356
1357                 let mut tlv_stream = offer.as_tlv_stream();
1358                 tlv_stream.amount = Some(1000);
1359                 tlv_stream.currency = Some(b"USD");
1360
1361                 let mut encoded_offer = Vec::new();
1362                 tlv_stream.write(&mut encoded_offer).unwrap();
1363
1364                 if let Err(e) = Offer::try_from(encoded_offer) {
1365                         panic!("error parsing offer: {:?}", e);
1366                 }
1367
1368                 let mut tlv_stream = offer.as_tlv_stream();
1369                 tlv_stream.amount = None;
1370                 tlv_stream.currency = Some(b"USD");
1371
1372                 let mut encoded_offer = Vec::new();
1373                 tlv_stream.write(&mut encoded_offer).unwrap();
1374
1375                 match Offer::try_from(encoded_offer) {
1376                         Ok(_) => panic!("expected error"),
1377                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingAmount)),
1378                 }
1379
1380                 let mut tlv_stream = offer.as_tlv_stream();
1381                 tlv_stream.amount = Some(MAX_VALUE_MSAT + 1);
1382                 tlv_stream.currency = None;
1383
1384                 let mut encoded_offer = Vec::new();
1385                 tlv_stream.write(&mut encoded_offer).unwrap();
1386
1387                 match Offer::try_from(encoded_offer) {
1388                         Ok(_) => panic!("expected error"),
1389                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InvalidAmount)),
1390                 }
1391         }
1392
1393         #[test]
1394         fn parses_offer_with_description() {
1395                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1396                 if let Err(e) = offer.to_string().parse::<Offer>() {
1397                         panic!("error parsing offer: {:?}", e);
1398                 }
1399
1400                 let mut tlv_stream = offer.as_tlv_stream();
1401                 tlv_stream.description = None;
1402
1403                 let mut encoded_offer = Vec::new();
1404                 tlv_stream.write(&mut encoded_offer).unwrap();
1405
1406                 match Offer::try_from(encoded_offer) {
1407                         Ok(_) => panic!("expected error"),
1408                         Err(e) => {
1409                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription));
1410                         },
1411                 }
1412         }
1413
1414         #[test]
1415         fn parses_offer_with_paths() {
1416                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1417                         .path(BlindedPath {
1418                                 introduction_node_id: pubkey(40),
1419                                 blinding_point: pubkey(41),
1420                                 blinded_hops: vec![
1421                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1422                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1423                                 ],
1424                         })
1425                         .path(BlindedPath {
1426                                 introduction_node_id: pubkey(40),
1427                                 blinding_point: pubkey(41),
1428                                 blinded_hops: vec![
1429                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1430                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1431                                 ],
1432                         })
1433                         .build()
1434                         .unwrap();
1435                 if let Err(e) = offer.to_string().parse::<Offer>() {
1436                         panic!("error parsing offer: {:?}", e);
1437                 }
1438
1439                 let mut builder = OfferBuilder::new("foo".into(), pubkey(42));
1440                 builder.offer.paths = Some(vec![]);
1441
1442                 let offer = builder.build().unwrap();
1443                 if let Err(e) = offer.to_string().parse::<Offer>() {
1444                         panic!("error parsing offer: {:?}", e);
1445                 }
1446         }
1447
1448         #[test]
1449         fn parses_offer_with_quantity() {
1450                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1451                         .supported_quantity(Quantity::One)
1452                         .build()
1453                         .unwrap();
1454                 if let Err(e) = offer.to_string().parse::<Offer>() {
1455                         panic!("error parsing offer: {:?}", e);
1456                 }
1457
1458                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1459                         .supported_quantity(Quantity::Unbounded)
1460                         .build()
1461                         .unwrap();
1462                 if let Err(e) = offer.to_string().parse::<Offer>() {
1463                         panic!("error parsing offer: {:?}", e);
1464                 }
1465
1466                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1467                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(10).unwrap()))
1468                         .build()
1469                         .unwrap();
1470                 if let Err(e) = offer.to_string().parse::<Offer>() {
1471                         panic!("error parsing offer: {:?}", e);
1472                 }
1473
1474                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1475                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(1).unwrap()))
1476                         .build()
1477                         .unwrap();
1478                 if let Err(e) = offer.to_string().parse::<Offer>() {
1479                         panic!("error parsing offer: {:?}", e);
1480                 }
1481         }
1482
1483         #[test]
1484         fn parses_offer_with_node_id() {
1485                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1486                 if let Err(e) = offer.to_string().parse::<Offer>() {
1487                         panic!("error parsing offer: {:?}", e);
1488                 }
1489
1490                 let mut tlv_stream = offer.as_tlv_stream();
1491                 tlv_stream.node_id = None;
1492
1493                 let mut encoded_offer = Vec::new();
1494                 tlv_stream.write(&mut encoded_offer).unwrap();
1495
1496                 match Offer::try_from(encoded_offer) {
1497                         Ok(_) => panic!("expected error"),
1498                         Err(e) => {
1499                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingSigningPubkey));
1500                         },
1501                 }
1502         }
1503
1504         #[test]
1505         fn fails_parsing_offer_with_extra_tlv_records() {
1506                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1507
1508                 let mut encoded_offer = Vec::new();
1509                 offer.write(&mut encoded_offer).unwrap();
1510                 BigSize(80).write(&mut encoded_offer).unwrap();
1511                 BigSize(32).write(&mut encoded_offer).unwrap();
1512                 [42u8; 32].write(&mut encoded_offer).unwrap();
1513
1514                 match Offer::try_from(encoded_offer) {
1515                         Ok(_) => panic!("expected error"),
1516                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1517                 }
1518         }
1519 }
1520
1521 #[cfg(test)]
1522 mod bech32_tests {
1523         use super::{Bolt12ParseError, Offer};
1524         use bitcoin::bech32;
1525         use crate::ln::msgs::DecodeError;
1526
1527         #[test]
1528         fn encodes_offer_as_bech32_without_checksum() {
1529                 let encoded_offer = "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg";
1530                 let offer = dbg!(encoded_offer.parse::<Offer>().unwrap());
1531                 let reencoded_offer = offer.to_string();
1532                 dbg!(reencoded_offer.parse::<Offer>().unwrap());
1533                 assert_eq!(reencoded_offer, encoded_offer);
1534         }
1535
1536         #[test]
1537         fn parses_bech32_encoded_offers() {
1538                 let offers = [
1539                         // BOLT 12 test vectors
1540                         "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1541                         "l+no1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1542                         "lno1pqps7sjqpgt+yzm3qv4uxzmtsd3jjqer9wd3hy6tsw3+5k7msjzfpy7nz5yqcn+ygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd+5xvxg",
1543                         "lno1pqps7sjqpgt+ yzm3qv4uxzmtsd3jjqer9wd3hy6tsw3+  5k7msjzfpy7nz5yqcn+\nygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd+\r\n 5xvxg",
1544                 ];
1545                 for encoded_offer in &offers {
1546                         if let Err(e) = encoded_offer.parse::<Offer>() {
1547                                 panic!("Invalid offer ({:?}): {}", e, encoded_offer);
1548                         }
1549                 }
1550         }
1551
1552         #[test]
1553         fn fails_parsing_bech32_encoded_offers_with_invalid_continuations() {
1554                 let offers = [
1555                         // BOLT 12 test vectors
1556                         "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg+",
1557                         "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg+ ",
1558                         "+lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1559                         "+ lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1560                         "ln++o1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1561                 ];
1562                 for encoded_offer in &offers {
1563                         match encoded_offer.parse::<Offer>() {
1564                                 Ok(_) => panic!("Valid offer: {}", encoded_offer),
1565                                 Err(e) => assert_eq!(e, Bolt12ParseError::InvalidContinuation),
1566                         }
1567                 }
1568
1569         }
1570
1571         #[test]
1572         fn fails_parsing_bech32_encoded_offer_with_invalid_hrp() {
1573                 let encoded_offer = "lni1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg";
1574                 match encoded_offer.parse::<Offer>() {
1575                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1576                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidBech32Hrp),
1577                 }
1578         }
1579
1580         #[test]
1581         fn fails_parsing_bech32_encoded_offer_with_invalid_bech32_data() {
1582                 let encoded_offer = "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxo";
1583                 match encoded_offer.parse::<Offer>() {
1584                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1585                         Err(e) => assert_eq!(e, Bolt12ParseError::Bech32(bech32::Error::InvalidChar('o'))),
1586                 }
1587         }
1588
1589         #[test]
1590         fn fails_parsing_bech32_encoded_offer_with_invalid_tlv_data() {
1591                 let encoded_offer = "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxgqqqqq";
1592                 match encoded_offer.parse::<Offer>() {
1593                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1594                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1595                 }
1596         }
1597 }