_ 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::ParseError;
  28 //! use lightning::util::ser::{Readable, Writeable};
  29 //!
  30 //! # use lightning::onion_message::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<(), ParseError> {
  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::chain::keysinterface::EntropySource;
  78 use crate::io;
  79 use crate::ln::features::OfferFeatures;
  80 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
  81 use crate::ln::msgs::MAX_VALUE_MSAT;
  82 use crate::offers::invoice_request::{DerivedPayerId, ExplicitPayerId, InvoiceRequestBuilder};
  83 use crate::offers::merkle::TlvStream;
  84 use crate::offers::parse::{Bech32Encode, ParseError, ParsedMessage, SemanticError};
  85 use crate::offers::signer::{Metadata, MetadataMaterial, self};
  86 use crate::onion_message::BlindedPath;
  87 use crate::util::ser::{HighZeroBytesDroppedBigSize, WithoutLength, Writeable, Writer};
  88 use crate::util::string::PrintableString;
  89
  90 use crate::prelude::*;
  91
  92 #[cfg(feature = "std")]
  93 use std::time::SystemTime;
  94
  95 pub(super) const IV_BYTES: &[u8; IV_LEN] = b"LDK Offer ~~~~~~";
  96
  97 /// Builds an [`Offer`] for the "offer to be paid" flow.
  98 ///
  99 /// See [module-level documentation] for usage.
 100 ///
 101 /// [module-level documentation]: self
 102 pub struct OfferBuilder<'a, M: MetadataStrategy, T: secp256k1::Signing> {
 103         offer: OfferContents,
 104         metadata_strategy: core::marker::PhantomData<M>,
 105         secp_ctx: Option<&'a Secp256k1<T>>,
 106 }
 107
 108 /// Indicates how [`Offer::metadata`] may be set.
 109 pub trait MetadataStrategy {}
 110
 111 /// [`Offer::metadata`] may be explicitly set or left empty.
 112 pub struct ExplicitMetadata {}
 113
 114 /// [`Offer::metadata`] will be derived.
 115 pub struct DerivedMetadata {}
 116
 117 impl MetadataStrategy for ExplicitMetadata {}
 118 impl MetadataStrategy for DerivedMetadata {}
 119
 120 impl<'a> OfferBuilder<'a, ExplicitMetadata, secp256k1::SignOnly> {
 121         /// Creates a new builder for an offer setting the [`Offer::description`] and using the
 122         /// [`Offer::signing_pubkey`] for signing invoices. The associated secret key must be remembered
 123         /// while the offer is valid.
 124         ///
 125         /// Use a different pubkey per offer to avoid correlating offers.
 126         pub fn new(description: String, signing_pubkey: PublicKey) -> Self {
 127                 OfferBuilder {
 128                         offer: OfferContents {
 129                                 chains: None, metadata: None, amount: None, description,
 130                                 features: OfferFeatures::empty(), absolute_expiry: None, issuer: None, paths: None,
 131                                 supported_quantity: Quantity::One, signing_pubkey,
 132                         },
 133                         metadata_strategy: core::marker::PhantomData,
 134                         secp_ctx: None,
 135                 }
 136         }
 137
 138         /// Sets the [`Offer::metadata`] to the given bytes.
 139         ///
 140         /// Successive calls to this method will override the previous setting.
 141         pub fn metadata(mut self, metadata: Vec<u8>) -> Result<Self, SemanticError> {
 142                 self.offer.metadata = Some(Metadata::Bytes(metadata));
 143                 Ok(self)
 144         }
 145 }
 146
 147 impl<'a, T: secp256k1::Signing> OfferBuilder<'a, DerivedMetadata, T> {
 148         /// Similar to [`OfferBuilder::new`] except, if [`OfferBuilder::path`] is called, the signing
 149         /// pubkey is derived from the given [`ExpandedKey`] and [`EntropySource`]. This provides
 150         /// recipient privacy by using a different signing pubkey for each offer. Otherwise, the
 151         /// provided `node_id` is used for the signing pubkey.
 152         ///
 153         /// Also, sets the metadata when [`OfferBuilder::build`] is called such that it can be used by
 154         /// [`InvoiceRequest::verify`] to determine if the request was produced for the offer given an
 155         /// [`ExpandedKey`].
 156         ///
 157         /// [`InvoiceRequest::verify`]: crate::offers::invoice_request::InvoiceRequest::verify
 158         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 159         pub fn deriving_signing_pubkey<ES: Deref>(
 160                 description: String, node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 161                 secp_ctx: &'a Secp256k1<T>
 162         ) -> Self where ES::Target: EntropySource {
 163                 let nonce = Nonce::from_entropy_source(entropy_source);
 164                 let derivation_material = MetadataMaterial::new(nonce, expanded_key, IV_BYTES);
 165                 let metadata = Metadata::DerivedSigningPubkey(derivation_material);
 166                 OfferBuilder {
 167                         offer: OfferContents {
 168                                 chains: None, metadata: Some(metadata), amount: None, description,
 169                                 features: OfferFeatures::empty(), absolute_expiry: None, issuer: None, paths: None,
 170                                 supported_quantity: Quantity::One, signing_pubkey: node_id,
 171                         },
 172                         metadata_strategy: core::marker::PhantomData,
 173                         secp_ctx: Some(secp_ctx),
 174                 }
 175         }
 176 }
 177
 178 impl<'a, M: MetadataStrategy, T: secp256k1::Signing> OfferBuilder<'a, M, T> {
 179         /// Adds the chain hash of the given [`Network`] to [`Offer::chains`]. If not called,
 180         /// the chain hash of [`Network::Bitcoin`] is assumed to be the only one supported.
 181         ///
 182         /// See [`Offer::chains`] on how this relates to the payment currency.
 183         ///
 184         /// Successive calls to this method will add another chain hash.
 185         pub fn chain(mut self, network: Network) -> Self {
 186                 let chains = self.offer.chains.get_or_insert_with(Vec::new);
 187                 let chain = ChainHash::using_genesis_block(network);
 188                 if !chains.contains(&chain) {
 189                         chains.push(chain);
 190                 }
 191
 192                 self
 193         }
 194
 195         /// Sets the [`Offer::amount`] as an [`Amount::Bitcoin`].
 196         ///
 197         /// Successive calls to this method will override the previous setting.
 198         pub fn amount_msats(self, amount_msats: u64) -> Self {
 199                 self.amount(Amount::Bitcoin { amount_msats })
 200         }
 201
 202         /// Sets the [`Offer::amount`].
 203         ///
 204         /// Successive calls to this method will override the previous setting.
 205         pub(super) fn amount(mut self, amount: Amount) -> Self {
 206                 self.offer.amount = Some(amount);
 207                 self
 208         }
 209
 210         /// Sets the [`Offer::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
 211         /// already passed is valid and can be checked for using [`Offer::is_expired`].
 212         ///
 213         /// Successive calls to this method will override the previous setting.
 214         pub fn absolute_expiry(mut self, absolute_expiry: Duration) -> Self {
 215                 self.offer.absolute_expiry = Some(absolute_expiry);
 216                 self
 217         }
 218
 219         /// Sets the [`Offer::issuer`].
 220         ///
 221         /// Successive calls to this method will override the previous setting.
 222         pub fn issuer(mut self, issuer: String) -> Self {
 223                 self.offer.issuer = Some(issuer);
 224                 self
 225         }
 226
 227         /// Adds a blinded path to [`Offer::paths`]. Must include at least one path if only connected by
 228         /// private channels or if [`Offer::signing_pubkey`] is not a public node id.
 229         ///
 230         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 231         /// adding duplicate paths.
 232         pub fn path(mut self, path: BlindedPath) -> Self {
 233                 self.offer.paths.get_or_insert_with(Vec::new).push(path);
 234                 self
 235         }
 236
 237         /// Sets the quantity of items for [`Offer::supported_quantity`]. If not called, defaults to
 238         /// [`Quantity::One`].
 239         ///
 240         /// Successive calls to this method will override the previous setting.
 241         pub fn supported_quantity(mut self, quantity: Quantity) -> Self {
 242                 self.offer.supported_quantity = quantity;
 243                 self
 244         }
 245
 246         /// Builds an [`Offer`] from the builder's settings.
 247         pub fn build(mut self) -> Result<Offer, SemanticError> {
 248                 match self.offer.amount {
 249                         Some(Amount::Bitcoin { amount_msats }) => {
 250                                 if amount_msats > MAX_VALUE_MSAT {
 251                                         return Err(SemanticError::InvalidAmount);
 252                                 }
 253                         },
 254                         Some(Amount::Currency { .. }) => return Err(SemanticError::UnsupportedCurrency),
 255                         None => {},
 256                 }
 257
 258                 if let Some(chains) = &self.offer.chains {
 259                         if chains.len() == 1 && chains[0] == self.offer.implied_chain() {
 260                                 self.offer.chains = None;
 261                         }
 262                 }
 263
 264                 Ok(self.build_without_checks())
 265         }
 266
 267         fn build_without_checks(mut self) -> Offer {
 268                 // Create the metadata for stateless verification of an InvoiceRequest.
 269                 if let Some(mut metadata) = self.offer.metadata.take() {
 270                         if metadata.has_derivation_material() {
 271                                 if self.offer.paths.is_none() {
 272                                         metadata = metadata.without_keys();
 273                                 }
 274
 275                                 let mut tlv_stream = self.offer.as_tlv_stream();
 276                                 debug_assert_eq!(tlv_stream.metadata, None);
 277                                 tlv_stream.metadata = None;
 278                                 if metadata.derives_keys() {
 279                                         tlv_stream.node_id = None;
 280                                 }
 281
 282                                 let (derived_metadata, keys) = metadata.derive_from(tlv_stream, self.secp_ctx);
 283                                 metadata = derived_metadata;
 284                                 if let Some(keys) = keys {
 285                                         self.offer.signing_pubkey = keys.public_key();
 286                                 }
 287                         }
 288
 289                         self.offer.metadata = Some(metadata);
 290                 }
 291
 292                 let mut bytes = Vec::new();
 293                 self.offer.write(&mut bytes).unwrap();
 294
 295                 Offer { bytes, contents: self.offer }
 296         }
 297 }
 298
 299 #[cfg(test)]
 300 impl<'a, M: MetadataStrategy, T: secp256k1::Signing> OfferBuilder<'a, M, T> {
 301         fn features_unchecked(mut self, features: OfferFeatures) -> Self {
 302                 self.offer.features = features;
 303                 self
 304         }
 305
 306         pub(super) fn build_unchecked(self) -> Offer {
 307                 self.build_without_checks()
 308         }
 309 }
 310
 311 /// An `Offer` is a potentially long-lived proposal for payment of a good or service.
 312 ///
 313 /// An offer is a precursor to an [`InvoiceRequest`]. A merchant publishes an offer from which a
 314 /// customer may request an [`Invoice`] for a specific quantity and using an amount sufficient to
 315 /// cover that quantity (i.e., at least `quantity * amount`). See [`Offer::amount`].
 316 ///
 317 /// Offers may be denominated in currency other than bitcoin but are ultimately paid using the
 318 /// latter.
 319 ///
 320 /// Through the use of [`BlindedPath`]s, offers provide recipient privacy.
 321 ///
 322 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 323 /// [`Invoice`]: crate::offers::invoice::Invoice
 324 #[derive(Clone, Debug)]
 325 #[cfg_attr(test, derive(PartialEq))]
 326 pub struct Offer {
 327         // The serialized offer. Needed when creating an `InvoiceRequest` if the offer contains unknown
 328         // fields.
 329         pub(super) bytes: Vec<u8>,
 330         pub(super) contents: OfferContents,
 331 }
 332
 333 /// The contents of an [`Offer`], which may be shared with an [`InvoiceRequest`] or an [`Invoice`].
 334 ///
 335 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 336 /// [`Invoice`]: crate::offers::invoice::Invoice
 337 #[derive(Clone, Debug)]
 338 #[cfg_attr(test, derive(PartialEq))]
 339 pub(super) struct OfferContents {
 340         chains: Option<Vec<ChainHash>>,
 341         metadata: Option<Metadata>,
 342         amount: Option<Amount>,
 343         description: String,
 344         features: OfferFeatures,
 345         absolute_expiry: Option<Duration>,
 346         issuer: Option<String>,
 347         paths: Option<Vec<BlindedPath>>,
 348         supported_quantity: Quantity,
 349         signing_pubkey: PublicKey,
 350 }
 351
 352 impl Offer {
 353         // TODO: Return a slice once ChainHash has constants.
 354         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1283
 355         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1286
 356         /// The chains that may be used when paying a requested invoice (e.g., bitcoin mainnet).
 357         /// Payments must be denominated in units of the minimal lightning-payable unit (e.g., msats)
 358         /// for the selected chain.
 359         pub fn chains(&self) -> Vec<ChainHash> {
 360                 self.contents.chains()
 361         }
 362
 363         pub(super) fn implied_chain(&self) -> ChainHash {
 364                 self.contents.implied_chain()
 365         }
 366
 367         /// Returns whether the given chain is supported by the offer.
 368         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 369                 self.contents.supports_chain(chain)
 370         }
 371
 372         // TODO: Link to corresponding method in `InvoiceRequest`.
 373         /// Opaque bytes set by the originator. Useful for authentication and validating fields since it
 374         /// is reflected in `invoice_request` messages along with all the other fields from the `offer`.
 375         pub fn metadata(&self) -> Option<&Vec<u8>> {
 376                 self.contents.metadata()
 377         }
 378
 379         /// The minimum amount required for a successful payment of a single item.
 380         pub fn amount(&self) -> Option<&Amount> {
 381                 self.contents.amount()
 382         }
 383
 384         /// A complete description of the purpose of the payment. Intended to be displayed to the user
 385         /// but with the caveat that it has not been verified in any way.
 386         pub fn description(&self) -> PrintableString {
 387                 PrintableString(&self.contents.description)
 388         }
 389
 390         /// Features pertaining to the offer.
 391         pub fn features(&self) -> &OfferFeatures {
 392                 &self.contents.features
 393         }
 394
 395         /// Duration since the Unix epoch when an invoice should no longer be requested.
 396         ///
 397         /// If `None`, the offer does not expire.
 398         pub fn absolute_expiry(&self) -> Option<Duration> {
 399                 self.contents.absolute_expiry
 400         }
 401
 402         /// Whether the offer has expired.
 403         #[cfg(feature = "std")]
 404         pub fn is_expired(&self) -> bool {
 405                 self.contents.is_expired()
 406         }
 407
 408         /// The issuer of the offer, possibly beginning with `user@domain` or `domain`. Intended to be
 409         /// displayed to the user but with the caveat that it has not been verified in any way.
 410         pub fn issuer(&self) -> Option<PrintableString> {
 411                 self.contents.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 412         }
 413
 414         /// Paths to the recipient originating from publicly reachable nodes. Blinded paths provide
 415         /// recipient privacy by obfuscating its node id.
 416         pub fn paths(&self) -> &[BlindedPath] {
 417                 self.contents.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 418         }
 419
 420         /// The quantity of items supported.
 421         pub fn supported_quantity(&self) -> Quantity {
 422                 self.contents.supported_quantity()
 423         }
 424
 425         /// Returns whether the given quantity is valid for the offer.
 426         pub fn is_valid_quantity(&self, quantity: u64) -> bool {
 427                 self.contents.is_valid_quantity(quantity)
 428         }
 429
 430         /// Returns whether a quantity is expected in an [`InvoiceRequest`] for the offer.
 431         ///
 432         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 433         pub fn expects_quantity(&self) -> bool {
 434                 self.contents.expects_quantity()
 435         }
 436
 437         /// The public key used by the recipient to sign invoices.
 438         pub fn signing_pubkey(&self) -> PublicKey {
 439                 self.contents.signing_pubkey()
 440         }
 441
 442         /// Similar to [`Offer::request_invoice`] except it:
 443         /// - derives the [`InvoiceRequest::payer_id`] such that a different key can be used for each
 444         ///   request, and
 445         /// - sets the [`InvoiceRequest::metadata`] when [`InvoiceRequestBuilder::build`] is called such
 446         ///   that it can be used by [`Invoice::verify`] to determine if the invoice was requested using
 447         ///   a base [`ExpandedKey`] from which the payer id was derived.
 448         ///
 449         /// Useful to protect the sender's privacy.
 450         ///
 451         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 452         /// [`InvoiceRequest::metadata`]: crate::offers::invoice_request::InvoiceRequest::metadata
 453         /// [`Invoice::verify`]: crate::offers::invoice::Invoice::verify
 454         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 455         pub fn request_invoice_deriving_payer_id<'a, 'b, ES: Deref, T: secp256k1::Signing>(
 456                 &'a self, expanded_key: &ExpandedKey, entropy_source: ES, secp_ctx: &'b Secp256k1<T>
 457         ) -> Result<InvoiceRequestBuilder<'a, 'b, DerivedPayerId, T>, SemanticError>
 458         where
 459                 ES::Target: EntropySource,
 460         {
 461                 if self.features().requires_unknown_bits() {
 462                         return Err(SemanticError::UnknownRequiredFeatures);
 463                 }
 464
 465                 Ok(InvoiceRequestBuilder::deriving_payer_id(self, expanded_key, entropy_source, secp_ctx))
 466         }
 467
 468         /// Similar to [`Offer::request_invoice_deriving_payer_id`] except uses `payer_id` for the
 469         /// [`InvoiceRequest::payer_id`] instead of deriving a different key for each request.
 470         ///
 471         /// Useful for recurring payments using the same `payer_id` with different invoices.
 472         ///
 473         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 474         pub fn request_invoice_deriving_metadata<ES: Deref>(
 475                 &self, payer_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES
 476         ) -> Result<InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>, SemanticError>
 477         where
 478                 ES::Target: EntropySource,
 479         {
 480                 if self.features().requires_unknown_bits() {
 481                         return Err(SemanticError::UnknownRequiredFeatures);
 482                 }
 483
 484                 Ok(InvoiceRequestBuilder::deriving_metadata(self, payer_id, expanded_key, entropy_source))
 485         }
 486
 487         /// Creates an [`InvoiceRequestBuilder`] for the offer with the given `metadata` and `payer_id`,
 488         /// which will be reflected in the `Invoice` response.
 489         ///
 490         /// The `metadata` is useful for including information about the derivation of `payer_id` such
 491         /// that invoice response handling can be stateless. Also serves as payer-provided entropy while
 492         /// hashing in the signature calculation.
 493         ///
 494         /// This should not leak any information such as by using a simple BIP-32 derivation path.
 495         /// Otherwise, payments may be correlated.
 496         ///
 497         /// Errors if the offer contains unknown required features.
 498         ///
 499         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 500         pub fn request_invoice(
 501                 &self, metadata: Vec<u8>, payer_id: PublicKey
 502         ) -> Result<InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>, SemanticError> {
 503                 if self.features().requires_unknown_bits() {
 504                         return Err(SemanticError::UnknownRequiredFeatures);
 505                 }
 506
 507                 Ok(InvoiceRequestBuilder::new(self, metadata, payer_id))
 508         }
 509
 510         #[cfg(test)]
 511         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 512                 self.contents.as_tlv_stream()
 513         }
 514 }
 515
 516 impl AsRef<[u8]> for Offer {
 517         fn as_ref(&self) -> &[u8] {
 518                 &self.bytes
 519         }
 520 }
 521
 522 impl OfferContents {
 523         pub fn chains(&self) -> Vec<ChainHash> {
 524                 self.chains.as_ref().cloned().unwrap_or_else(|| vec![self.implied_chain()])
 525         }
 526
 527         pub fn implied_chain(&self) -> ChainHash {
 528                 ChainHash::using_genesis_block(Network::Bitcoin)
 529         }
 530
 531         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 532                 self.chains().contains(&chain)
 533         }
 534
 535         pub fn metadata(&self) -> Option<&Vec<u8>> {
 536                 self.metadata.as_ref().and_then(|metadata| metadata.as_bytes())
 537         }
 538
 539         #[cfg(feature = "std")]
 540         pub(super) fn is_expired(&self) -> bool {
 541                 match self.absolute_expiry {
 542                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
 543                                 Ok(elapsed) => elapsed > seconds_from_epoch,
 544                                 Err(_) => false,
 545                         },
 546                         None => false,
 547                 }
 548         }
 549
 550         pub fn amount(&self) -> Option<&Amount> {
 551                 self.amount.as_ref()
 552         }
 553
 554         pub(super) fn check_amount_msats_for_quantity(
 555                 &self, amount_msats: Option<u64>, quantity: Option<u64>
 556         ) -> Result<(), SemanticError> {
 557                 let offer_amount_msats = match self.amount {
 558                         None => 0,
 559                         Some(Amount::Bitcoin { amount_msats }) => amount_msats,
 560                         Some(Amount::Currency { .. }) => return Err(SemanticError::UnsupportedCurrency),
 561                 };
 562
 563                 if !self.expects_quantity() || quantity.is_some() {
 564                         let expected_amount_msats = offer_amount_msats.checked_mul(quantity.unwrap_or(1))
 565                                 .ok_or(SemanticError::InvalidAmount)?;
 566                         let amount_msats = amount_msats.unwrap_or(expected_amount_msats);
 567
 568                         if amount_msats < expected_amount_msats {
 569                                 return Err(SemanticError::InsufficientAmount);
 570                         }
 571
 572                         if amount_msats > MAX_VALUE_MSAT {
 573                                 return Err(SemanticError::InvalidAmount);
 574                         }
 575                 }
 576
 577                 Ok(())
 578         }
 579
 580         pub fn supported_quantity(&self) -> Quantity {
 581                 self.supported_quantity
 582         }
 583
 584         pub(super) fn check_quantity(&self, quantity: Option<u64>) -> Result<(), SemanticError> {
 585                 let expects_quantity = self.expects_quantity();
 586                 match quantity {
 587                         None if expects_quantity => Err(SemanticError::MissingQuantity),
 588                         Some(_) if !expects_quantity => Err(SemanticError::UnexpectedQuantity),
 589                         Some(quantity) if !self.is_valid_quantity(quantity) => {
 590                                 Err(SemanticError::InvalidQuantity)
 591                         },
 592                         _ => Ok(()),
 593                 }
 594         }
 595
 596         fn is_valid_quantity(&self, quantity: u64) -> bool {
 597                 match self.supported_quantity {
 598                         Quantity::Bounded(n) => quantity <= n.get(),
 599                         Quantity::Unbounded => quantity > 0,
 600                         Quantity::One => quantity == 1,
 601                 }
 602         }
 603
 604         fn expects_quantity(&self) -> bool {
 605                 match self.supported_quantity {
 606                         Quantity::Bounded(_) => true,
 607                         Quantity::Unbounded => true,
 608                         Quantity::One => false,
 609                 }
 610         }
 611
 612         pub(super) fn signing_pubkey(&self) -> PublicKey {
 613                 self.signing_pubkey
 614         }
 615
 616         /// Verifies that the offer metadata was produced from the offer in the TLV stream.
 617         pub(super) fn verify<T: secp256k1::Signing>(
 618                 &self, bytes: &[u8], key: &ExpandedKey, secp_ctx: &Secp256k1<T>
 619         ) -> Result<Option<KeyPair>, ()> {
 620                 match self.metadata() {
 621                         Some(metadata) => {
 622                                 let tlv_stream = TlvStream::new(bytes).range(OFFER_TYPES).filter(|record| {
 623                                         match record.r#type {
 624                                                 OFFER_METADATA_TYPE => false,
 625                                                 OFFER_NODE_ID_TYPE => !self.metadata.as_ref().unwrap().derives_keys(),
 626                                                 _ => true,
 627                                         }
 628                                 });
 629                                 signer::verify_metadata(
 630                                         metadata, key, IV_BYTES, self.signing_pubkey(), tlv_stream, secp_ctx
 631                                 )
 632                         },
 633                         None => Err(()),
 634                 }
 635         }
 636
 637         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 638                 let (currency, amount) = match &self.amount {
 639                         None => (None, None),
 640                         Some(Amount::Bitcoin { amount_msats }) => (None, Some(*amount_msats)),
 641                         Some(Amount::Currency { iso4217_code, amount }) => (
 642                                 Some(iso4217_code), Some(*amount)
 643                         ),
 644                 };
 645
 646                 let features = {
 647                         if self.features == OfferFeatures::empty() { None } else { Some(&self.features) }
 648                 };
 649
 650                 OfferTlvStreamRef {
 651                         chains: self.chains.as_ref(),
 652                         metadata: self.metadata(),
 653                         currency,
 654                         amount,
 655                         description: Some(&self.description),
 656                         features,
 657                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 658                         paths: self.paths.as_ref(),
 659                         issuer: self.issuer.as_ref(),
 660                         quantity_max: self.supported_quantity.to_tlv_record(),
 661                         node_id: Some(&self.signing_pubkey),
 662                 }
 663         }
 664 }
 665
 666 impl Writeable for Offer {
 667         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 668                 WithoutLength(&self.bytes).write(writer)
 669         }
 670 }
 671
 672 impl Writeable for OfferContents {
 673         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 674                 self.as_tlv_stream().write(writer)
 675         }
 676 }
 677
 678 /// The minimum amount required for an item in an [`Offer`], denominated in either bitcoin or
 679 /// another currency.
 680 #[derive(Clone, Debug, PartialEq)]
 681 pub enum Amount {
 682         /// An amount of bitcoin.
 683         Bitcoin {
 684                 /// The amount in millisatoshi.
 685                 amount_msats: u64,
 686         },
 687         /// An amount of currency specified using ISO 4712.
 688         Currency {
 689                 /// The currency that the amount is denominated in.
 690                 iso4217_code: CurrencyCode,
 691                 /// The amount in the currency unit adjusted by the ISO 4712 exponent (e.g., USD cents).
 692                 amount: u64,
 693         },
 694 }
 695
 696 /// An ISO 4712 three-letter currency code (e.g., USD).
 697 pub type CurrencyCode = [u8; 3];
 698
 699 /// Quantity of items supported by an [`Offer`].
 700 #[derive(Clone, Copy, Debug, PartialEq)]
 701 pub enum Quantity {
 702         /// Up to a specific number of items (inclusive). Use when more than one item can be requested
 703         /// but is limited (e.g., because of per customer or inventory limits).
 704         ///
 705         /// May be used with `NonZeroU64::new(1)` but prefer to use [`Quantity::One`] if only one item
 706         /// is supported.
 707         Bounded(NonZeroU64),
 708         /// One or more items. Use when more than one item can be requested without any limit.
 709         Unbounded,
 710         /// Only one item. Use when only a single item can be requested.
 711         One,
 712 }
 713
 714 impl Quantity {
 715         fn to_tlv_record(&self) -> Option<u64> {
 716                 match self {
 717                         Quantity::Bounded(n) => Some(n.get()),
 718                         Quantity::Unbounded => Some(0),
 719                         Quantity::One => None,
 720                 }
 721         }
 722 }
 723
 724 /// Valid type range for offer TLV records.
 725 pub(super) const OFFER_TYPES: core::ops::Range<u64> = 1..80;
 726
 727 /// TLV record type for [`Offer::metadata`].
 728 const OFFER_METADATA_TYPE: u64 = 4;
 729
 730 /// TLV record type for [`Offer::signing_pubkey`].
 731 const OFFER_NODE_ID_TYPE: u64 = 22;
 732
 733 tlv_stream!(OfferTlvStream, OfferTlvStreamRef, OFFER_TYPES, {
 734         (2, chains: (Vec<ChainHash>, WithoutLength)),
 735         (OFFER_METADATA_TYPE, metadata: (Vec<u8>, WithoutLength)),
 736         (6, currency: CurrencyCode),
 737         (8, amount: (u64, HighZeroBytesDroppedBigSize)),
 738         (10, description: (String, WithoutLength)),
 739         (12, features: (OfferFeatures, WithoutLength)),
 740         (14, absolute_expiry: (u64, HighZeroBytesDroppedBigSize)),
 741         (16, paths: (Vec<BlindedPath>, WithoutLength)),
 742         (18, issuer: (String, WithoutLength)),
 743         (20, quantity_max: (u64, HighZeroBytesDroppedBigSize)),
 744         (OFFER_NODE_ID_TYPE, node_id: PublicKey),
 745 });
 746
 747 impl Bech32Encode for Offer {
 748         const BECH32_HRP: &'static str = "lno";
 749 }
 750
 751 impl FromStr for Offer {
 752         type Err = ParseError;
 753
 754         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 755                 Self::from_bech32_str(s)
 756         }
 757 }
 758
 759 impl TryFrom<Vec<u8>> for Offer {
 760         type Error = ParseError;
 761
 762         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 763                 let offer = ParsedMessage::<OfferTlvStream>::try_from(bytes)?;
 764                 let ParsedMessage { bytes, tlv_stream } = offer;
 765                 let contents = OfferContents::try_from(tlv_stream)?;
 766                 Ok(Offer { bytes, contents })
 767         }
 768 }
 769
 770 impl TryFrom<OfferTlvStream> for OfferContents {
 771         type Error = SemanticError;
 772
 773         fn try_from(tlv_stream: OfferTlvStream) -> Result<Self, Self::Error> {
 774                 let OfferTlvStream {
 775                         chains, metadata, currency, amount, description, features, absolute_expiry, paths,
 776                         issuer, quantity_max, node_id,
 777                 } = tlv_stream;
 778
 779                 let metadata = metadata.map(|metadata| Metadata::Bytes(metadata));
 780
 781                 let amount = match (currency, amount) {
 782                         (None, None) => None,
 783                         (None, Some(amount_msats)) if amount_msats > MAX_VALUE_MSAT => {
 784                                 return Err(SemanticError::InvalidAmount);
 785                         },
 786                         (None, Some(amount_msats)) => Some(Amount::Bitcoin { amount_msats }),
 787                         (Some(_), None) => return Err(SemanticError::MissingAmount),
 788                         (Some(iso4217_code), Some(amount)) => Some(Amount::Currency { iso4217_code, amount }),
 789                 };
 790
 791                 let description = match description {
 792                         None => return Err(SemanticError::MissingDescription),
 793                         Some(description) => description,
 794                 };
 795
 796                 let features = features.unwrap_or_else(OfferFeatures::empty);
 797
 798                 let absolute_expiry = absolute_expiry
 799                         .map(|seconds_from_epoch| Duration::from_secs(seconds_from_epoch));
 800
 801                 let supported_quantity = match quantity_max {
 802                         None => Quantity::One,
 803                         Some(0) => Quantity::Unbounded,
 804                         Some(n) => Quantity::Bounded(NonZeroU64::new(n).unwrap()),
 805                 };
 806
 807                 let signing_pubkey = match node_id {
 808                         None => return Err(SemanticError::MissingSigningPubkey),
 809                         Some(node_id) => node_id,
 810                 };
 811
 812                 Ok(OfferContents {
 813                         chains, metadata, amount, description, features, absolute_expiry, issuer, paths,
 814                         supported_quantity, signing_pubkey,
 815                 })
 816         }
 817 }
 818
 819 impl core::fmt::Display for Offer {
 820         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 821                 self.fmt_bech32_str(f)
 822         }
 823 }
 824
 825 #[cfg(test)]
 826 mod tests {
 827         use super::{Amount, Offer, OfferBuilder, OfferTlvStreamRef, Quantity};
 828
 829         use bitcoin::blockdata::constants::ChainHash;
 830         use bitcoin::network::constants::Network;
 831         use bitcoin::secp256k1::Secp256k1;
 832         use core::convert::TryFrom;
 833         use core::num::NonZeroU64;
 834         use core::time::Duration;
 835         use crate::chain::keysinterface::KeyMaterial;
 836         use crate::ln::features::OfferFeatures;
 837         use crate::ln::inbound_payment::ExpandedKey;
 838         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 839         use crate::offers::parse::{ParseError, SemanticError};
 840         use crate::offers::test_utils::*;
 841         use crate::onion_message::{BlindedHop, BlindedPath};
 842         use crate::util::ser::{BigSize, Writeable};
 843         use crate::util::string::PrintableString;
 844
 845         #[test]
 846         fn builds_offer_with_defaults() {
 847                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
 848
 849                 let mut buffer = Vec::new();
 850                 offer.write(&mut buffer).unwrap();
 851
 852                 assert_eq!(offer.bytes, buffer.as_slice());
 853                 assert_eq!(offer.chains(), vec![ChainHash::using_genesis_block(Network::Bitcoin)]);
 854                 assert!(offer.supports_chain(ChainHash::using_genesis_block(Network::Bitcoin)));
 855                 assert_eq!(offer.metadata(), None);
 856                 assert_eq!(offer.amount(), None);
 857                 assert_eq!(offer.description(), PrintableString("foo"));
 858                 assert_eq!(offer.features(), &OfferFeatures::empty());
 859                 assert_eq!(offer.absolute_expiry(), None);
 860                 #[cfg(feature = "std")]
 861                 assert!(!offer.is_expired());
 862                 assert_eq!(offer.paths(), &[]);
 863                 assert_eq!(offer.issuer(), None);
 864                 assert_eq!(offer.supported_quantity(), Quantity::One);
 865                 assert_eq!(offer.signing_pubkey(), pubkey(42));
 866
 867                 assert_eq!(
 868                         offer.as_tlv_stream(),
 869                         OfferTlvStreamRef {
 870                                 chains: None,
 871                                 metadata: None,
 872                                 currency: None,
 873                                 amount: None,
 874                                 description: Some(&String::from("foo")),
 875                                 features: None,
 876                                 absolute_expiry: None,
 877                                 paths: None,
 878                                 issuer: None,
 879                                 quantity_max: None,
 880                                 node_id: Some(&pubkey(42)),
 881                         },
 882                 );
 883
 884                 if let Err(e) = Offer::try_from(buffer) {
 885                         panic!("error parsing offer: {:?}", e);
 886                 }
 887         }
 888
 889         #[test]
 890         fn builds_offer_with_chains() {
 891                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
 892                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
 893
 894                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 895                         .chain(Network::Bitcoin)
 896                         .build()
 897                         .unwrap();
 898                 assert!(offer.supports_chain(mainnet));
 899                 assert_eq!(offer.chains(), vec![mainnet]);
 900                 assert_eq!(offer.as_tlv_stream().chains, None);
 901
 902                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 903                         .chain(Network::Testnet)
 904                         .build()
 905                         .unwrap();
 906                 assert!(offer.supports_chain(testnet));
 907                 assert_eq!(offer.chains(), vec![testnet]);
 908                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 909
 910                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 911                         .chain(Network::Testnet)
 912                         .chain(Network::Testnet)
 913                         .build()
 914                         .unwrap();
 915                 assert!(offer.supports_chain(testnet));
 916                 assert_eq!(offer.chains(), vec![testnet]);
 917                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 918
 919                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 920                         .chain(Network::Bitcoin)
 921                         .chain(Network::Testnet)
 922                         .build()
 923                         .unwrap();
 924                 assert!(offer.supports_chain(mainnet));
 925                 assert!(offer.supports_chain(testnet));
 926                 assert_eq!(offer.chains(), vec![mainnet, testnet]);
 927                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![mainnet, testnet]));
 928         }
 929
 930         #[test]
 931         fn builds_offer_with_metadata() {
 932                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 933                         .metadata(vec![42; 32]).unwrap()
 934                         .build()
 935                         .unwrap();
 936                 assert_eq!(offer.metadata(), Some(&vec![42; 32]));
 937                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![42; 32]));
 938
 939                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 940                         .metadata(vec![42; 32]).unwrap()
 941                         .metadata(vec![43; 32]).unwrap()
 942                         .build()
 943                         .unwrap();
 944                 assert_eq!(offer.metadata(), Some(&vec![43; 32]));
 945                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![43; 32]));
 946         }
 947
 948         #[test]
 949         fn builds_offer_with_metadata_derived() {
 950                 let desc = "foo".to_string();
 951                 let node_id = recipient_pubkey();
 952                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
 953                 let entropy = FixedEntropy {};
 954                 let secp_ctx = Secp256k1::new();
 955
 956                 let offer = OfferBuilder
 957                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
 958                         .amount_msats(1000)
 959                         .build().unwrap();
 960                 assert_eq!(offer.signing_pubkey(), node_id);
 961
 962                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 963                         .build().unwrap()
 964                         .sign(payer_sign).unwrap();
 965                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
 966
 967                 // Fails verification with altered offer field
 968                 let mut tlv_stream = offer.as_tlv_stream();
 969                 tlv_stream.amount = Some(100);
 970
 971                 let mut encoded_offer = Vec::new();
 972                 tlv_stream.write(&mut encoded_offer).unwrap();
 973
 974                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
 975                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 976                         .build().unwrap()
 977                         .sign(payer_sign).unwrap();
 978                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
 979
 980                 // Fails verification with altered metadata
 981                 let mut tlv_stream = offer.as_tlv_stream();
 982                 let metadata = tlv_stream.metadata.unwrap().iter().copied().rev().collect();
 983                 tlv_stream.metadata = Some(&metadata);
 984
 985                 let mut encoded_offer = Vec::new();
 986                 tlv_stream.write(&mut encoded_offer).unwrap();
 987
 988                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
 989                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 990                         .build().unwrap()
 991                         .sign(payer_sign).unwrap();
 992                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
 993         }
 994
 995         #[test]
 996         fn builds_offer_with_derived_signing_pubkey() {
 997                 let desc = "foo".to_string();
 998                 let node_id = recipient_pubkey();
 999                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1000                 let entropy = FixedEntropy {};
1001                 let secp_ctx = Secp256k1::new();
1002
1003                 let blinded_path = BlindedPath {
1004                         introduction_node_id: pubkey(40),
1005                         blinding_point: pubkey(41),
1006                         blinded_hops: vec![
1007                                 BlindedHop { blinded_node_id: pubkey(42), encrypted_payload: vec![0; 43] },
1008                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
1009                         ],
1010                 };
1011
1012                 let offer = OfferBuilder
1013                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
1014                         .amount_msats(1000)
1015                         .path(blinded_path)
1016                         .build().unwrap();
1017                 assert_ne!(offer.signing_pubkey(), node_id);
1018
1019                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1020                         .build().unwrap()
1021                         .sign(payer_sign).unwrap();
1022                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
1023
1024                 // Fails verification with altered offer field
1025                 let mut tlv_stream = offer.as_tlv_stream();
1026                 tlv_stream.amount = Some(100);
1027
1028                 let mut encoded_offer = Vec::new();
1029                 tlv_stream.write(&mut encoded_offer).unwrap();
1030
1031                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1032                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1033                         .build().unwrap()
1034                         .sign(payer_sign).unwrap();
1035                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1036
1037                 // Fails verification with altered signing pubkey
1038                 let mut tlv_stream = offer.as_tlv_stream();
1039                 let signing_pubkey = pubkey(1);
1040                 tlv_stream.node_id = Some(&signing_pubkey);
1041
1042                 let mut encoded_offer = Vec::new();
1043                 tlv_stream.write(&mut encoded_offer).unwrap();
1044
1045                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1046                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1047                         .build().unwrap()
1048                         .sign(payer_sign).unwrap();
1049                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1050         }
1051
1052         #[test]
1053         fn builds_offer_with_amount() {
1054                 let bitcoin_amount = Amount::Bitcoin { amount_msats: 1000 };
1055                 let currency_amount = Amount::Currency { iso4217_code: *b"USD", amount: 10 };
1056
1057                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1058                         .amount_msats(1000)
1059                         .build()
1060                         .unwrap();
1061                 let tlv_stream = offer.as_tlv_stream();
1062                 assert_eq!(offer.amount(), Some(&bitcoin_amount));
1063                 assert_eq!(tlv_stream.amount, Some(1000));
1064                 assert_eq!(tlv_stream.currency, None);
1065
1066                 let builder = OfferBuilder::new("foo".into(), pubkey(42))
1067                         .amount(currency_amount.clone());
1068                 let tlv_stream = builder.offer.as_tlv_stream();
1069                 assert_eq!(builder.offer.amount, Some(currency_amount.clone()));
1070                 assert_eq!(tlv_stream.amount, Some(10));
1071                 assert_eq!(tlv_stream.currency, Some(b"USD"));
1072                 match builder.build() {
1073                         Ok(_) => panic!("expected error"),
1074                         Err(e) => assert_eq!(e, SemanticError::UnsupportedCurrency),
1075                 }
1076
1077                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1078                         .amount(currency_amount.clone())
1079                         .amount(bitcoin_amount.clone())
1080                         .build()
1081                         .unwrap();
1082                 let tlv_stream = offer.as_tlv_stream();
1083                 assert_eq!(tlv_stream.amount, Some(1000));
1084                 assert_eq!(tlv_stream.currency, None);
1085
1086                 let invalid_amount = Amount::Bitcoin { amount_msats: MAX_VALUE_MSAT + 1 };
1087                 match OfferBuilder::new("foo".into(), pubkey(42)).amount(invalid_amount).build() {
1088                         Ok(_) => panic!("expected error"),
1089                         Err(e) => assert_eq!(e, SemanticError::InvalidAmount),
1090                 }
1091         }
1092
1093         #[test]
1094         fn builds_offer_with_features() {
1095                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1096                         .features_unchecked(OfferFeatures::unknown())
1097                         .build()
1098                         .unwrap();
1099                 assert_eq!(offer.features(), &OfferFeatures::unknown());
1100                 assert_eq!(offer.as_tlv_stream().features, Some(&OfferFeatures::unknown()));
1101
1102                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1103                         .features_unchecked(OfferFeatures::unknown())
1104                         .features_unchecked(OfferFeatures::empty())
1105                         .build()
1106                         .unwrap();
1107                 assert_eq!(offer.features(), &OfferFeatures::empty());
1108                 assert_eq!(offer.as_tlv_stream().features, None);
1109         }
1110
1111         #[test]
1112         fn builds_offer_with_absolute_expiry() {
1113                 let future_expiry = Duration::from_secs(u64::max_value());
1114                 let past_expiry = Duration::from_secs(0);
1115
1116                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1117                         .absolute_expiry(future_expiry)
1118                         .build()
1119                         .unwrap();
1120                 #[cfg(feature = "std")]
1121                 assert!(!offer.is_expired());
1122                 assert_eq!(offer.absolute_expiry(), Some(future_expiry));
1123                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(future_expiry.as_secs()));
1124
1125                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1126                         .absolute_expiry(future_expiry)
1127                         .absolute_expiry(past_expiry)
1128                         .build()
1129                         .unwrap();
1130                 #[cfg(feature = "std")]
1131                 assert!(offer.is_expired());
1132                 assert_eq!(offer.absolute_expiry(), Some(past_expiry));
1133                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(past_expiry.as_secs()));
1134         }
1135
1136         #[test]
1137         fn builds_offer_with_paths() {
1138                 let paths = vec![
1139                         BlindedPath {
1140                                 introduction_node_id: pubkey(40),
1141                                 blinding_point: pubkey(41),
1142                                 blinded_hops: vec![
1143                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1144                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1145                                 ],
1146                         },
1147                         BlindedPath {
1148                                 introduction_node_id: pubkey(40),
1149                                 blinding_point: pubkey(41),
1150                                 blinded_hops: vec![
1151                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1152                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1153                                 ],
1154                         },
1155                 ];
1156
1157                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1158                         .path(paths[0].clone())
1159                         .path(paths[1].clone())
1160                         .build()
1161                         .unwrap();
1162                 let tlv_stream = offer.as_tlv_stream();
1163                 assert_eq!(offer.paths(), paths.as_slice());
1164                 assert_eq!(offer.signing_pubkey(), pubkey(42));
1165                 assert_ne!(pubkey(42), pubkey(44));
1166                 assert_eq!(tlv_stream.paths, Some(&paths));
1167                 assert_eq!(tlv_stream.node_id, Some(&pubkey(42)));
1168         }
1169
1170         #[test]
1171         fn builds_offer_with_issuer() {
1172                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1173                         .issuer("bar".into())
1174                         .build()
1175                         .unwrap();
1176                 assert_eq!(offer.issuer(), Some(PrintableString("bar")));
1177                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("bar")));
1178
1179                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1180                         .issuer("bar".into())
1181                         .issuer("baz".into())
1182                         .build()
1183                         .unwrap();
1184                 assert_eq!(offer.issuer(), Some(PrintableString("baz")));
1185                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("baz")));
1186         }
1187
1188         #[test]
1189         fn builds_offer_with_supported_quantity() {
1190                 let one = NonZeroU64::new(1).unwrap();
1191                 let ten = NonZeroU64::new(10).unwrap();
1192
1193                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1194                         .supported_quantity(Quantity::One)
1195                         .build()
1196                         .unwrap();
1197                 let tlv_stream = offer.as_tlv_stream();
1198                 assert_eq!(offer.supported_quantity(), Quantity::One);
1199                 assert_eq!(tlv_stream.quantity_max, None);
1200
1201                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1202                         .supported_quantity(Quantity::Unbounded)
1203                         .build()
1204                         .unwrap();
1205                 let tlv_stream = offer.as_tlv_stream();
1206                 assert_eq!(offer.supported_quantity(), Quantity::Unbounded);
1207                 assert_eq!(tlv_stream.quantity_max, Some(0));
1208
1209                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1210                         .supported_quantity(Quantity::Bounded(ten))
1211                         .build()
1212                         .unwrap();
1213                 let tlv_stream = offer.as_tlv_stream();
1214                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(ten));
1215                 assert_eq!(tlv_stream.quantity_max, Some(10));
1216
1217                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1218                         .supported_quantity(Quantity::Bounded(one))
1219                         .build()
1220                         .unwrap();
1221                 let tlv_stream = offer.as_tlv_stream();
1222                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(one));
1223                 assert_eq!(tlv_stream.quantity_max, Some(1));
1224
1225                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1226                         .supported_quantity(Quantity::Bounded(ten))
1227                         .supported_quantity(Quantity::One)
1228                         .build()
1229                         .unwrap();
1230                 let tlv_stream = offer.as_tlv_stream();
1231                 assert_eq!(offer.supported_quantity(), Quantity::One);
1232                 assert_eq!(tlv_stream.quantity_max, None);
1233         }
1234
1235         #[test]
1236         fn fails_requesting_invoice_with_unknown_required_features() {
1237                 match OfferBuilder::new("foo".into(), pubkey(42))
1238                         .features_unchecked(OfferFeatures::unknown())
1239                         .build().unwrap()
1240                         .request_invoice(vec![1; 32], pubkey(43))
1241                 {
1242                         Ok(_) => panic!("expected error"),
1243                         Err(e) => assert_eq!(e, SemanticError::UnknownRequiredFeatures),
1244                 }
1245         }
1246
1247         #[test]
1248         fn parses_offer_with_chains() {
1249                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1250                         .chain(Network::Bitcoin)
1251                         .chain(Network::Testnet)
1252                         .build()
1253                         .unwrap();
1254                 if let Err(e) = offer.to_string().parse::<Offer>() {
1255                         panic!("error parsing offer: {:?}", e);
1256                 }
1257         }
1258
1259         #[test]
1260         fn parses_offer_with_amount() {
1261                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1262                         .amount(Amount::Bitcoin { amount_msats: 1000 })
1263                         .build()
1264                         .unwrap();
1265                 if let Err(e) = offer.to_string().parse::<Offer>() {
1266                         panic!("error parsing offer: {:?}", e);
1267                 }
1268
1269                 let mut tlv_stream = offer.as_tlv_stream();
1270                 tlv_stream.amount = Some(1000);
1271                 tlv_stream.currency = Some(b"USD");
1272
1273                 let mut encoded_offer = Vec::new();
1274                 tlv_stream.write(&mut encoded_offer).unwrap();
1275
1276                 if let Err(e) = Offer::try_from(encoded_offer) {
1277                         panic!("error parsing offer: {:?}", e);
1278                 }
1279
1280                 let mut tlv_stream = offer.as_tlv_stream();
1281                 tlv_stream.amount = None;
1282                 tlv_stream.currency = Some(b"USD");
1283
1284                 let mut encoded_offer = Vec::new();
1285                 tlv_stream.write(&mut encoded_offer).unwrap();
1286
1287                 match Offer::try_from(encoded_offer) {
1288                         Ok(_) => panic!("expected error"),
1289                         Err(e) => assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingAmount)),
1290                 }
1291
1292                 let mut tlv_stream = offer.as_tlv_stream();
1293                 tlv_stream.amount = Some(MAX_VALUE_MSAT + 1);
1294                 tlv_stream.currency = None;
1295
1296                 let mut encoded_offer = Vec::new();
1297                 tlv_stream.write(&mut encoded_offer).unwrap();
1298
1299                 match Offer::try_from(encoded_offer) {
1300                         Ok(_) => panic!("expected error"),
1301                         Err(e) => assert_eq!(e, ParseError::InvalidSemantics(SemanticError::InvalidAmount)),
1302                 }
1303         }
1304
1305         #[test]
1306         fn parses_offer_with_description() {
1307                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1308                 if let Err(e) = offer.to_string().parse::<Offer>() {
1309                         panic!("error parsing offer: {:?}", e);
1310                 }
1311
1312                 let mut tlv_stream = offer.as_tlv_stream();
1313                 tlv_stream.description = None;
1314
1315                 let mut encoded_offer = Vec::new();
1316                 tlv_stream.write(&mut encoded_offer).unwrap();
1317
1318                 match Offer::try_from(encoded_offer) {
1319                         Ok(_) => panic!("expected error"),
1320                         Err(e) => {
1321                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingDescription));
1322                         },
1323                 }
1324         }
1325
1326         #[test]
1327         fn parses_offer_with_paths() {
1328                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1329                         .path(BlindedPath {
1330                                 introduction_node_id: pubkey(40),
1331                                 blinding_point: pubkey(41),
1332                                 blinded_hops: vec![
1333                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1334                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1335                                 ],
1336                         })
1337                         .path(BlindedPath {
1338                                 introduction_node_id: pubkey(40),
1339                                 blinding_point: pubkey(41),
1340                                 blinded_hops: vec![
1341                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1342                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1343                                 ],
1344                         })
1345                         .build()
1346                         .unwrap();
1347                 if let Err(e) = offer.to_string().parse::<Offer>() {
1348                         panic!("error parsing offer: {:?}", e);
1349                 }
1350
1351                 let mut builder = OfferBuilder::new("foo".into(), pubkey(42));
1352                 builder.offer.paths = Some(vec![]);
1353
1354                 let offer = builder.build().unwrap();
1355                 if let Err(e) = offer.to_string().parse::<Offer>() {
1356                         panic!("error parsing offer: {:?}", e);
1357                 }
1358         }
1359
1360         #[test]
1361         fn parses_offer_with_quantity() {
1362                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1363                         .supported_quantity(Quantity::One)
1364                         .build()
1365                         .unwrap();
1366                 if let Err(e) = offer.to_string().parse::<Offer>() {
1367                         panic!("error parsing offer: {:?}", e);
1368                 }
1369
1370                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1371                         .supported_quantity(Quantity::Unbounded)
1372                         .build()
1373                         .unwrap();
1374                 if let Err(e) = offer.to_string().parse::<Offer>() {
1375                         panic!("error parsing offer: {:?}", e);
1376                 }
1377
1378                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1379                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(10).unwrap()))
1380                         .build()
1381                         .unwrap();
1382                 if let Err(e) = offer.to_string().parse::<Offer>() {
1383                         panic!("error parsing offer: {:?}", e);
1384                 }
1385
1386                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1387                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(1).unwrap()))
1388                         .build()
1389                         .unwrap();
1390                 if let Err(e) = offer.to_string().parse::<Offer>() {
1391                         panic!("error parsing offer: {:?}", e);
1392                 }
1393         }
1394
1395         #[test]
1396         fn parses_offer_with_node_id() {
1397                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1398                 if let Err(e) = offer.to_string().parse::<Offer>() {
1399                         panic!("error parsing offer: {:?}", e);
1400                 }
1401
1402                 let mut tlv_stream = offer.as_tlv_stream();
1403                 tlv_stream.node_id = None;
1404
1405                 let mut encoded_offer = Vec::new();
1406                 tlv_stream.write(&mut encoded_offer).unwrap();
1407
1408                 match Offer::try_from(encoded_offer) {
1409                         Ok(_) => panic!("expected error"),
1410                         Err(e) => {
1411                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingSigningPubkey));
1412                         },
1413                 }
1414         }
1415
1416         #[test]
1417         fn fails_parsing_offer_with_extra_tlv_records() {
1418                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1419
1420                 let mut encoded_offer = Vec::new();
1421                 offer.write(&mut encoded_offer).unwrap();
1422                 BigSize(80).write(&mut encoded_offer).unwrap();
1423                 BigSize(32).write(&mut encoded_offer).unwrap();
1424                 [42u8; 32].write(&mut encoded_offer).unwrap();
1425
1426                 match Offer::try_from(encoded_offer) {
1427                         Ok(_) => panic!("expected error"),
1428                         Err(e) => assert_eq!(e, ParseError::Decode(DecodeError::InvalidValue)),
1429                 }
1430         }
1431 }
1432
1433 #[cfg(test)]
1434 mod bech32_tests {
1435         use super::{Offer, ParseError};
1436         use bitcoin::bech32;
1437         use crate::ln::msgs::DecodeError;
1438
1439         // TODO: Remove once test vectors are updated.
1440         #[ignore]
1441         #[test]
1442         fn encodes_offer_as_bech32_without_checksum() {
1443                 let encoded_offer = "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy";
1444                 let offer = dbg!(encoded_offer.parse::<Offer>().unwrap());
1445                 let reencoded_offer = offer.to_string();
1446                 dbg!(reencoded_offer.parse::<Offer>().unwrap());
1447                 assert_eq!(reencoded_offer, encoded_offer);
1448         }
1449
1450         // TODO: Remove once test vectors are updated.
1451         #[ignore]
1452         #[test]
1453         fn parses_bech32_encoded_offers() {
1454                 let offers = [
1455                         // BOLT 12 test vectors
1456                         "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1457                         "l+no1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1458                         "l+no1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1459                         "lno1qcp4256ypqpq+86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn0+0fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0+sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qs+y",
1460                         "lno1qcp4256ypqpq+ 86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn0+  0fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0+\nsqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43l+\r\nastpwuh73k29qs+\r  y",
1461                         // Two blinded paths
1462                         "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",
1463                 ];
1464                 for encoded_offer in &offers {
1465                         if let Err(e) = encoded_offer.parse::<Offer>() {
1466                                 panic!("Invalid offer ({:?}): {}", e, encoded_offer);
1467                         }
1468                 }
1469         }
1470
1471         #[test]
1472         fn fails_parsing_bech32_encoded_offers_with_invalid_continuations() {
1473                 let offers = [
1474                         // BOLT 12 test vectors
1475                         "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy+",
1476                         "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy+ ",
1477                         "+lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1478                         "+ lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1479                         "ln++o1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1480                 ];
1481                 for encoded_offer in &offers {
1482                         match encoded_offer.parse::<Offer>() {
1483                                 Ok(_) => panic!("Valid offer: {}", encoded_offer),
1484                                 Err(e) => assert_eq!(e, ParseError::InvalidContinuation),
1485                         }
1486                 }
1487
1488         }
1489
1490         #[test]
1491         fn fails_parsing_bech32_encoded_offer_with_invalid_hrp() {
1492                 let encoded_offer = "lni1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy";
1493                 match encoded_offer.parse::<Offer>() {
1494                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1495                         Err(e) => assert_eq!(e, ParseError::InvalidBech32Hrp),
1496                 }
1497         }
1498
1499         #[test]
1500         fn fails_parsing_bech32_encoded_offer_with_invalid_bech32_data() {
1501                 let encoded_offer = "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qso";
1502                 match encoded_offer.parse::<Offer>() {
1503                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1504                         Err(e) => assert_eq!(e, ParseError::Bech32(bech32::Error::InvalidChar('o'))),
1505                 }
1506         }
1507
1508         #[test]
1509         fn fails_parsing_bech32_encoded_offer_with_invalid_tlv_data() {
1510                 let encoded_offer = "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsyqqqqq";
1511                 match encoded_offer.parse::<Offer>() {
1512                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1513                         Err(e) => assert_eq!(e, ParseError::Decode(DecodeError::InvalidValue)),
1514                 }
1515         }
1516 }