_ 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::blinded_path::BlindedPath;
  31 //! # #[cfg(feature = "std")]
  32 //! # use std::time::SystemTime;
  33 //! #
  34 //! # fn create_blinded_path() -> BlindedPath { unimplemented!() }
  35 //! # fn create_another_blinded_path() -> BlindedPath { unimplemented!() }
  36 //! #
  37 //! # #[cfg(feature = "std")]
  38 //! # fn build() -> Result<(), 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::blinded_path::BlindedPath;
  80 use crate::ln::features::OfferFeatures;
  81 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
  82 use crate::ln::msgs::MAX_VALUE_MSAT;
  83 use crate::offers::invoice_request::{DerivedPayerId, ExplicitPayerId, InvoiceRequestBuilder};
  84 use crate::offers::merkle::TlvStream;
  85 use crate::offers::parse::{Bech32Encode, ParseError, ParsedMessage, SemanticError};
  86 use crate::offers::signer::{Metadata, MetadataMaterial, self};
  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                 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         pub fn description(&self) -> PrintableString {
 540                 PrintableString(&self.description)
 541         }
 542
 543         #[cfg(feature = "std")]
 544         pub(super) fn is_expired(&self) -> bool {
 545                 match self.absolute_expiry {
 546                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
 547                                 Ok(elapsed) => elapsed > seconds_from_epoch,
 548                                 Err(_) => false,
 549                         },
 550                         None => false,
 551                 }
 552         }
 553
 554         pub fn amount(&self) -> Option<&Amount> {
 555                 self.amount.as_ref()
 556         }
 557
 558         pub(super) fn check_amount_msats_for_quantity(
 559                 &self, amount_msats: Option<u64>, quantity: Option<u64>
 560         ) -> Result<(), SemanticError> {
 561                 let offer_amount_msats = match self.amount {
 562                         None => 0,
 563                         Some(Amount::Bitcoin { amount_msats }) => amount_msats,
 564                         Some(Amount::Currency { .. }) => return Err(SemanticError::UnsupportedCurrency),
 565                 };
 566
 567                 if !self.expects_quantity() || quantity.is_some() {
 568                         let expected_amount_msats = offer_amount_msats.checked_mul(quantity.unwrap_or(1))
 569                                 .ok_or(SemanticError::InvalidAmount)?;
 570                         let amount_msats = amount_msats.unwrap_or(expected_amount_msats);
 571
 572                         if amount_msats < expected_amount_msats {
 573                                 return Err(SemanticError::InsufficientAmount);
 574                         }
 575
 576                         if amount_msats > MAX_VALUE_MSAT {
 577                                 return Err(SemanticError::InvalidAmount);
 578                         }
 579                 }
 580
 581                 Ok(())
 582         }
 583
 584         pub fn supported_quantity(&self) -> Quantity {
 585                 self.supported_quantity
 586         }
 587
 588         pub(super) fn check_quantity(&self, quantity: Option<u64>) -> Result<(), SemanticError> {
 589                 let expects_quantity = self.expects_quantity();
 590                 match quantity {
 591                         None if expects_quantity => Err(SemanticError::MissingQuantity),
 592                         Some(_) if !expects_quantity => Err(SemanticError::UnexpectedQuantity),
 593                         Some(quantity) if !self.is_valid_quantity(quantity) => {
 594                                 Err(SemanticError::InvalidQuantity)
 595                         },
 596                         _ => Ok(()),
 597                 }
 598         }
 599
 600         fn is_valid_quantity(&self, quantity: u64) -> bool {
 601                 match self.supported_quantity {
 602                         Quantity::Bounded(n) => quantity <= n.get(),
 603                         Quantity::Unbounded => quantity > 0,
 604                         Quantity::One => quantity == 1,
 605                 }
 606         }
 607
 608         fn expects_quantity(&self) -> bool {
 609                 match self.supported_quantity {
 610                         Quantity::Bounded(_) => true,
 611                         Quantity::Unbounded => true,
 612                         Quantity::One => false,
 613                 }
 614         }
 615
 616         pub(super) fn signing_pubkey(&self) -> PublicKey {
 617                 self.signing_pubkey
 618         }
 619
 620         /// Verifies that the offer metadata was produced from the offer in the TLV stream.
 621         pub(super) fn verify<T: secp256k1::Signing>(
 622                 &self, bytes: &[u8], key: &ExpandedKey, secp_ctx: &Secp256k1<T>
 623         ) -> Result<Option<KeyPair>, ()> {
 624                 match self.metadata() {
 625                         Some(metadata) => {
 626                                 let tlv_stream = TlvStream::new(bytes).range(OFFER_TYPES).filter(|record| {
 627                                         match record.r#type {
 628                                                 OFFER_METADATA_TYPE => false,
 629                                                 OFFER_NODE_ID_TYPE => !self.metadata.as_ref().unwrap().derives_keys(),
 630                                                 _ => true,
 631                                         }
 632                                 });
 633                                 signer::verify_metadata(
 634                                         metadata, key, IV_BYTES, self.signing_pubkey(), tlv_stream, secp_ctx
 635                                 )
 636                         },
 637                         None => Err(()),
 638                 }
 639         }
 640
 641         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 642                 let (currency, amount) = match &self.amount {
 643                         None => (None, None),
 644                         Some(Amount::Bitcoin { amount_msats }) => (None, Some(*amount_msats)),
 645                         Some(Amount::Currency { iso4217_code, amount }) => (
 646                                 Some(iso4217_code), Some(*amount)
 647                         ),
 648                 };
 649
 650                 let features = {
 651                         if self.features == OfferFeatures::empty() { None } else { Some(&self.features) }
 652                 };
 653
 654                 OfferTlvStreamRef {
 655                         chains: self.chains.as_ref(),
 656                         metadata: self.metadata(),
 657                         currency,
 658                         amount,
 659                         description: Some(&self.description),
 660                         features,
 661                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 662                         paths: self.paths.as_ref(),
 663                         issuer: self.issuer.as_ref(),
 664                         quantity_max: self.supported_quantity.to_tlv_record(),
 665                         node_id: Some(&self.signing_pubkey),
 666                 }
 667         }
 668 }
 669
 670 impl Writeable for Offer {
 671         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 672                 WithoutLength(&self.bytes).write(writer)
 673         }
 674 }
 675
 676 impl Writeable for OfferContents {
 677         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 678                 self.as_tlv_stream().write(writer)
 679         }
 680 }
 681
 682 /// The minimum amount required for an item in an [`Offer`], denominated in either bitcoin or
 683 /// another currency.
 684 #[derive(Clone, Debug, PartialEq)]
 685 pub enum Amount {
 686         /// An amount of bitcoin.
 687         Bitcoin {
 688                 /// The amount in millisatoshi.
 689                 amount_msats: u64,
 690         },
 691         /// An amount of currency specified using ISO 4712.
 692         Currency {
 693                 /// The currency that the amount is denominated in.
 694                 iso4217_code: CurrencyCode,
 695                 /// The amount in the currency unit adjusted by the ISO 4712 exponent (e.g., USD cents).
 696                 amount: u64,
 697         },
 698 }
 699
 700 /// An ISO 4712 three-letter currency code (e.g., USD).
 701 pub type CurrencyCode = [u8; 3];
 702
 703 /// Quantity of items supported by an [`Offer`].
 704 #[derive(Clone, Copy, Debug, PartialEq)]
 705 pub enum Quantity {
 706         /// Up to a specific number of items (inclusive). Use when more than one item can be requested
 707         /// but is limited (e.g., because of per customer or inventory limits).
 708         ///
 709         /// May be used with `NonZeroU64::new(1)` but prefer to use [`Quantity::One`] if only one item
 710         /// is supported.
 711         Bounded(NonZeroU64),
 712         /// One or more items. Use when more than one item can be requested without any limit.
 713         Unbounded,
 714         /// Only one item. Use when only a single item can be requested.
 715         One,
 716 }
 717
 718 impl Quantity {
 719         fn to_tlv_record(&self) -> Option<u64> {
 720                 match self {
 721                         Quantity::Bounded(n) => Some(n.get()),
 722                         Quantity::Unbounded => Some(0),
 723                         Quantity::One => None,
 724                 }
 725         }
 726 }
 727
 728 /// Valid type range for offer TLV records.
 729 pub(super) const OFFER_TYPES: core::ops::Range<u64> = 1..80;
 730
 731 /// TLV record type for [`Offer::metadata`].
 732 const OFFER_METADATA_TYPE: u64 = 4;
 733
 734 /// TLV record type for [`Offer::signing_pubkey`].
 735 const OFFER_NODE_ID_TYPE: u64 = 22;
 736
 737 tlv_stream!(OfferTlvStream, OfferTlvStreamRef, OFFER_TYPES, {
 738         (2, chains: (Vec<ChainHash>, WithoutLength)),
 739         (OFFER_METADATA_TYPE, metadata: (Vec<u8>, WithoutLength)),
 740         (6, currency: CurrencyCode),
 741         (8, amount: (u64, HighZeroBytesDroppedBigSize)),
 742         (10, description: (String, WithoutLength)),
 743         (12, features: (OfferFeatures, WithoutLength)),
 744         (14, absolute_expiry: (u64, HighZeroBytesDroppedBigSize)),
 745         (16, paths: (Vec<BlindedPath>, WithoutLength)),
 746         (18, issuer: (String, WithoutLength)),
 747         (20, quantity_max: (u64, HighZeroBytesDroppedBigSize)),
 748         (OFFER_NODE_ID_TYPE, node_id: PublicKey),
 749 });
 750
 751 impl Bech32Encode for Offer {
 752         const BECH32_HRP: &'static str = "lno";
 753 }
 754
 755 impl FromStr for Offer {
 756         type Err = ParseError;
 757
 758         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 759                 Self::from_bech32_str(s)
 760         }
 761 }
 762
 763 impl TryFrom<Vec<u8>> for Offer {
 764         type Error = ParseError;
 765
 766         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 767                 let offer = ParsedMessage::<OfferTlvStream>::try_from(bytes)?;
 768                 let ParsedMessage { bytes, tlv_stream } = offer;
 769                 let contents = OfferContents::try_from(tlv_stream)?;
 770                 Ok(Offer { bytes, contents })
 771         }
 772 }
 773
 774 impl TryFrom<OfferTlvStream> for OfferContents {
 775         type Error = SemanticError;
 776
 777         fn try_from(tlv_stream: OfferTlvStream) -> Result<Self, Self::Error> {
 778                 let OfferTlvStream {
 779                         chains, metadata, currency, amount, description, features, absolute_expiry, paths,
 780                         issuer, quantity_max, node_id,
 781                 } = tlv_stream;
 782
 783                 let metadata = metadata.map(|metadata| Metadata::Bytes(metadata));
 784
 785                 let amount = match (currency, amount) {
 786                         (None, None) => None,
 787                         (None, Some(amount_msats)) if amount_msats > MAX_VALUE_MSAT => {
 788                                 return Err(SemanticError::InvalidAmount);
 789                         },
 790                         (None, Some(amount_msats)) => Some(Amount::Bitcoin { amount_msats }),
 791                         (Some(_), None) => return Err(SemanticError::MissingAmount),
 792                         (Some(iso4217_code), Some(amount)) => Some(Amount::Currency { iso4217_code, amount }),
 793                 };
 794
 795                 let description = match description {
 796                         None => return Err(SemanticError::MissingDescription),
 797                         Some(description) => description,
 798                 };
 799
 800                 let features = features.unwrap_or_else(OfferFeatures::empty);
 801
 802                 let absolute_expiry = absolute_expiry
 803                         .map(|seconds_from_epoch| Duration::from_secs(seconds_from_epoch));
 804
 805                 let supported_quantity = match quantity_max {
 806                         None => Quantity::One,
 807                         Some(0) => Quantity::Unbounded,
 808                         Some(n) => Quantity::Bounded(NonZeroU64::new(n).unwrap()),
 809                 };
 810
 811                 let signing_pubkey = match node_id {
 812                         None => return Err(SemanticError::MissingSigningPubkey),
 813                         Some(node_id) => node_id,
 814                 };
 815
 816                 Ok(OfferContents {
 817                         chains, metadata, amount, description, features, absolute_expiry, issuer, paths,
 818                         supported_quantity, signing_pubkey,
 819                 })
 820         }
 821 }
 822
 823 impl core::fmt::Display for Offer {
 824         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 825                 self.fmt_bech32_str(f)
 826         }
 827 }
 828
 829 #[cfg(test)]
 830 mod tests {
 831         use super::{Amount, Offer, OfferBuilder, OfferTlvStreamRef, Quantity};
 832
 833         use bitcoin::blockdata::constants::ChainHash;
 834         use bitcoin::network::constants::Network;
 835         use bitcoin::secp256k1::Secp256k1;
 836         use core::convert::TryFrom;
 837         use core::num::NonZeroU64;
 838         use core::time::Duration;
 839         use crate::blinded_path::{BlindedHop, BlindedPath};
 840         use crate::chain::keysinterface::KeyMaterial;
 841         use crate::ln::features::OfferFeatures;
 842         use crate::ln::inbound_payment::ExpandedKey;
 843         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 844         use crate::offers::parse::{ParseError, SemanticError};
 845         use crate::offers::test_utils::*;
 846         use crate::util::ser::{BigSize, Writeable};
 847         use crate::util::string::PrintableString;
 848
 849         #[test]
 850         fn builds_offer_with_defaults() {
 851                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
 852
 853                 let mut buffer = Vec::new();
 854                 offer.write(&mut buffer).unwrap();
 855
 856                 assert_eq!(offer.bytes, buffer.as_slice());
 857                 assert_eq!(offer.chains(), vec![ChainHash::using_genesis_block(Network::Bitcoin)]);
 858                 assert!(offer.supports_chain(ChainHash::using_genesis_block(Network::Bitcoin)));
 859                 assert_eq!(offer.metadata(), None);
 860                 assert_eq!(offer.amount(), None);
 861                 assert_eq!(offer.description(), PrintableString("foo"));
 862                 assert_eq!(offer.features(), &OfferFeatures::empty());
 863                 assert_eq!(offer.absolute_expiry(), None);
 864                 #[cfg(feature = "std")]
 865                 assert!(!offer.is_expired());
 866                 assert_eq!(offer.paths(), &[]);
 867                 assert_eq!(offer.issuer(), None);
 868                 assert_eq!(offer.supported_quantity(), Quantity::One);
 869                 assert_eq!(offer.signing_pubkey(), pubkey(42));
 870
 871                 assert_eq!(
 872                         offer.as_tlv_stream(),
 873                         OfferTlvStreamRef {
 874                                 chains: None,
 875                                 metadata: None,
 876                                 currency: None,
 877                                 amount: None,
 878                                 description: Some(&String::from("foo")),
 879                                 features: None,
 880                                 absolute_expiry: None,
 881                                 paths: None,
 882                                 issuer: None,
 883                                 quantity_max: None,
 884                                 node_id: Some(&pubkey(42)),
 885                         },
 886                 );
 887
 888                 if let Err(e) = Offer::try_from(buffer) {
 889                         panic!("error parsing offer: {:?}", e);
 890                 }
 891         }
 892
 893         #[test]
 894         fn builds_offer_with_chains() {
 895                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
 896                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
 897
 898                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 899                         .chain(Network::Bitcoin)
 900                         .build()
 901                         .unwrap();
 902                 assert!(offer.supports_chain(mainnet));
 903                 assert_eq!(offer.chains(), vec![mainnet]);
 904                 assert_eq!(offer.as_tlv_stream().chains, None);
 905
 906                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 907                         .chain(Network::Testnet)
 908                         .build()
 909                         .unwrap();
 910                 assert!(offer.supports_chain(testnet));
 911                 assert_eq!(offer.chains(), vec![testnet]);
 912                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 913
 914                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 915                         .chain(Network::Testnet)
 916                         .chain(Network::Testnet)
 917                         .build()
 918                         .unwrap();
 919                 assert!(offer.supports_chain(testnet));
 920                 assert_eq!(offer.chains(), vec![testnet]);
 921                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 922
 923                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 924                         .chain(Network::Bitcoin)
 925                         .chain(Network::Testnet)
 926                         .build()
 927                         .unwrap();
 928                 assert!(offer.supports_chain(mainnet));
 929                 assert!(offer.supports_chain(testnet));
 930                 assert_eq!(offer.chains(), vec![mainnet, testnet]);
 931                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![mainnet, testnet]));
 932         }
 933
 934         #[test]
 935         fn builds_offer_with_metadata() {
 936                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 937                         .metadata(vec![42; 32]).unwrap()
 938                         .build()
 939                         .unwrap();
 940                 assert_eq!(offer.metadata(), Some(&vec![42; 32]));
 941                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![42; 32]));
 942
 943                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 944                         .metadata(vec![42; 32]).unwrap()
 945                         .metadata(vec![43; 32]).unwrap()
 946                         .build()
 947                         .unwrap();
 948                 assert_eq!(offer.metadata(), Some(&vec![43; 32]));
 949                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![43; 32]));
 950         }
 951
 952         #[test]
 953         fn builds_offer_with_metadata_derived() {
 954                 let desc = "foo".to_string();
 955                 let node_id = recipient_pubkey();
 956                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
 957                 let entropy = FixedEntropy {};
 958                 let secp_ctx = Secp256k1::new();
 959
 960                 let offer = OfferBuilder
 961                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
 962                         .amount_msats(1000)
 963                         .build().unwrap();
 964                 assert_eq!(offer.signing_pubkey(), node_id);
 965
 966                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 967                         .build().unwrap()
 968                         .sign(payer_sign).unwrap();
 969                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
 970
 971                 // Fails verification with altered offer field
 972                 let mut tlv_stream = offer.as_tlv_stream();
 973                 tlv_stream.amount = Some(100);
 974
 975                 let mut encoded_offer = Vec::new();
 976                 tlv_stream.write(&mut encoded_offer).unwrap();
 977
 978                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
 979                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 980                         .build().unwrap()
 981                         .sign(payer_sign).unwrap();
 982                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
 983
 984                 // Fails verification with altered metadata
 985                 let mut tlv_stream = offer.as_tlv_stream();
 986                 let metadata = tlv_stream.metadata.unwrap().iter().copied().rev().collect();
 987                 tlv_stream.metadata = Some(&metadata);
 988
 989                 let mut encoded_offer = Vec::new();
 990                 tlv_stream.write(&mut encoded_offer).unwrap();
 991
 992                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
 993                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 994                         .build().unwrap()
 995                         .sign(payer_sign).unwrap();
 996                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
 997         }
 998
 999         #[test]
1000         fn builds_offer_with_derived_signing_pubkey() {
1001                 let desc = "foo".to_string();
1002                 let node_id = recipient_pubkey();
1003                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1004                 let entropy = FixedEntropy {};
1005                 let secp_ctx = Secp256k1::new();
1006
1007                 let blinded_path = BlindedPath {
1008                         introduction_node_id: pubkey(40),
1009                         blinding_point: pubkey(41),
1010                         blinded_hops: vec![
1011                                 BlindedHop { blinded_node_id: pubkey(42), encrypted_payload: vec![0; 43] },
1012                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
1013                         ],
1014                 };
1015
1016                 let offer = OfferBuilder
1017                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
1018                         .amount_msats(1000)
1019                         .path(blinded_path)
1020                         .build().unwrap();
1021                 assert_ne!(offer.signing_pubkey(), node_id);
1022
1023                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1024                         .build().unwrap()
1025                         .sign(payer_sign).unwrap();
1026                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
1027
1028                 // Fails verification with altered offer field
1029                 let mut tlv_stream = offer.as_tlv_stream();
1030                 tlv_stream.amount = Some(100);
1031
1032                 let mut encoded_offer = Vec::new();
1033                 tlv_stream.write(&mut encoded_offer).unwrap();
1034
1035                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1036                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1037                         .build().unwrap()
1038                         .sign(payer_sign).unwrap();
1039                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1040
1041                 // Fails verification with altered signing pubkey
1042                 let mut tlv_stream = offer.as_tlv_stream();
1043                 let signing_pubkey = pubkey(1);
1044                 tlv_stream.node_id = Some(&signing_pubkey);
1045
1046                 let mut encoded_offer = Vec::new();
1047                 tlv_stream.write(&mut encoded_offer).unwrap();
1048
1049                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1050                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1051                         .build().unwrap()
1052                         .sign(payer_sign).unwrap();
1053                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1054         }
1055
1056         #[test]
1057         fn builds_offer_with_amount() {
1058                 let bitcoin_amount = Amount::Bitcoin { amount_msats: 1000 };
1059                 let currency_amount = Amount::Currency { iso4217_code: *b"USD", amount: 10 };
1060
1061                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1062                         .amount_msats(1000)
1063                         .build()
1064                         .unwrap();
1065                 let tlv_stream = offer.as_tlv_stream();
1066                 assert_eq!(offer.amount(), Some(&bitcoin_amount));
1067                 assert_eq!(tlv_stream.amount, Some(1000));
1068                 assert_eq!(tlv_stream.currency, None);
1069
1070                 let builder = OfferBuilder::new("foo".into(), pubkey(42))
1071                         .amount(currency_amount.clone());
1072                 let tlv_stream = builder.offer.as_tlv_stream();
1073                 assert_eq!(builder.offer.amount, Some(currency_amount.clone()));
1074                 assert_eq!(tlv_stream.amount, Some(10));
1075                 assert_eq!(tlv_stream.currency, Some(b"USD"));
1076                 match builder.build() {
1077                         Ok(_) => panic!("expected error"),
1078                         Err(e) => assert_eq!(e, SemanticError::UnsupportedCurrency),
1079                 }
1080
1081                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1082                         .amount(currency_amount.clone())
1083                         .amount(bitcoin_amount.clone())
1084                         .build()
1085                         .unwrap();
1086                 let tlv_stream = offer.as_tlv_stream();
1087                 assert_eq!(tlv_stream.amount, Some(1000));
1088                 assert_eq!(tlv_stream.currency, None);
1089
1090                 let invalid_amount = Amount::Bitcoin { amount_msats: MAX_VALUE_MSAT + 1 };
1091                 match OfferBuilder::new("foo".into(), pubkey(42)).amount(invalid_amount).build() {
1092                         Ok(_) => panic!("expected error"),
1093                         Err(e) => assert_eq!(e, SemanticError::InvalidAmount),
1094                 }
1095         }
1096
1097         #[test]
1098         fn builds_offer_with_features() {
1099                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1100                         .features_unchecked(OfferFeatures::unknown())
1101                         .build()
1102                         .unwrap();
1103                 assert_eq!(offer.features(), &OfferFeatures::unknown());
1104                 assert_eq!(offer.as_tlv_stream().features, Some(&OfferFeatures::unknown()));
1105
1106                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1107                         .features_unchecked(OfferFeatures::unknown())
1108                         .features_unchecked(OfferFeatures::empty())
1109                         .build()
1110                         .unwrap();
1111                 assert_eq!(offer.features(), &OfferFeatures::empty());
1112                 assert_eq!(offer.as_tlv_stream().features, None);
1113         }
1114
1115         #[test]
1116         fn builds_offer_with_absolute_expiry() {
1117                 let future_expiry = Duration::from_secs(u64::max_value());
1118                 let past_expiry = Duration::from_secs(0);
1119
1120                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1121                         .absolute_expiry(future_expiry)
1122                         .build()
1123                         .unwrap();
1124                 #[cfg(feature = "std")]
1125                 assert!(!offer.is_expired());
1126                 assert_eq!(offer.absolute_expiry(), Some(future_expiry));
1127                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(future_expiry.as_secs()));
1128
1129                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1130                         .absolute_expiry(future_expiry)
1131                         .absolute_expiry(past_expiry)
1132                         .build()
1133                         .unwrap();
1134                 #[cfg(feature = "std")]
1135                 assert!(offer.is_expired());
1136                 assert_eq!(offer.absolute_expiry(), Some(past_expiry));
1137                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(past_expiry.as_secs()));
1138         }
1139
1140         #[test]
1141         fn builds_offer_with_paths() {
1142                 let paths = vec![
1143                         BlindedPath {
1144                                 introduction_node_id: pubkey(40),
1145                                 blinding_point: pubkey(41),
1146                                 blinded_hops: vec![
1147                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1148                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1149                                 ],
1150                         },
1151                         BlindedPath {
1152                                 introduction_node_id: pubkey(40),
1153                                 blinding_point: pubkey(41),
1154                                 blinded_hops: vec![
1155                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1156                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1157                                 ],
1158                         },
1159                 ];
1160
1161                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1162                         .path(paths[0].clone())
1163                         .path(paths[1].clone())
1164                         .build()
1165                         .unwrap();
1166                 let tlv_stream = offer.as_tlv_stream();
1167                 assert_eq!(offer.paths(), paths.as_slice());
1168                 assert_eq!(offer.signing_pubkey(), pubkey(42));
1169                 assert_ne!(pubkey(42), pubkey(44));
1170                 assert_eq!(tlv_stream.paths, Some(&paths));
1171                 assert_eq!(tlv_stream.node_id, Some(&pubkey(42)));
1172         }
1173
1174         #[test]
1175         fn builds_offer_with_issuer() {
1176                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1177                         .issuer("bar".into())
1178                         .build()
1179                         .unwrap();
1180                 assert_eq!(offer.issuer(), Some(PrintableString("bar")));
1181                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("bar")));
1182
1183                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1184                         .issuer("bar".into())
1185                         .issuer("baz".into())
1186                         .build()
1187                         .unwrap();
1188                 assert_eq!(offer.issuer(), Some(PrintableString("baz")));
1189                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("baz")));
1190         }
1191
1192         #[test]
1193         fn builds_offer_with_supported_quantity() {
1194                 let one = NonZeroU64::new(1).unwrap();
1195                 let ten = NonZeroU64::new(10).unwrap();
1196
1197                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1198                         .supported_quantity(Quantity::One)
1199                         .build()
1200                         .unwrap();
1201                 let tlv_stream = offer.as_tlv_stream();
1202                 assert_eq!(offer.supported_quantity(), Quantity::One);
1203                 assert_eq!(tlv_stream.quantity_max, None);
1204
1205                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1206                         .supported_quantity(Quantity::Unbounded)
1207                         .build()
1208                         .unwrap();
1209                 let tlv_stream = offer.as_tlv_stream();
1210                 assert_eq!(offer.supported_quantity(), Quantity::Unbounded);
1211                 assert_eq!(tlv_stream.quantity_max, Some(0));
1212
1213                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1214                         .supported_quantity(Quantity::Bounded(ten))
1215                         .build()
1216                         .unwrap();
1217                 let tlv_stream = offer.as_tlv_stream();
1218                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(ten));
1219                 assert_eq!(tlv_stream.quantity_max, Some(10));
1220
1221                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1222                         .supported_quantity(Quantity::Bounded(one))
1223                         .build()
1224                         .unwrap();
1225                 let tlv_stream = offer.as_tlv_stream();
1226                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(one));
1227                 assert_eq!(tlv_stream.quantity_max, Some(1));
1228
1229                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1230                         .supported_quantity(Quantity::Bounded(ten))
1231                         .supported_quantity(Quantity::One)
1232                         .build()
1233                         .unwrap();
1234                 let tlv_stream = offer.as_tlv_stream();
1235                 assert_eq!(offer.supported_quantity(), Quantity::One);
1236                 assert_eq!(tlv_stream.quantity_max, None);
1237         }
1238
1239         #[test]
1240         fn fails_requesting_invoice_with_unknown_required_features() {
1241                 match OfferBuilder::new("foo".into(), pubkey(42))
1242                         .features_unchecked(OfferFeatures::unknown())
1243                         .build().unwrap()
1244                         .request_invoice(vec![1; 32], pubkey(43))
1245                 {
1246                         Ok(_) => panic!("expected error"),
1247                         Err(e) => assert_eq!(e, SemanticError::UnknownRequiredFeatures),
1248                 }
1249         }
1250
1251         #[test]
1252         fn parses_offer_with_chains() {
1253                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1254                         .chain(Network::Bitcoin)
1255                         .chain(Network::Testnet)
1256                         .build()
1257                         .unwrap();
1258                 if let Err(e) = offer.to_string().parse::<Offer>() {
1259                         panic!("error parsing offer: {:?}", e);
1260                 }
1261         }
1262
1263         #[test]
1264         fn parses_offer_with_amount() {
1265                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1266                         .amount(Amount::Bitcoin { amount_msats: 1000 })
1267                         .build()
1268                         .unwrap();
1269                 if let Err(e) = offer.to_string().parse::<Offer>() {
1270                         panic!("error parsing offer: {:?}", e);
1271                 }
1272
1273                 let mut tlv_stream = offer.as_tlv_stream();
1274                 tlv_stream.amount = Some(1000);
1275                 tlv_stream.currency = Some(b"USD");
1276
1277                 let mut encoded_offer = Vec::new();
1278                 tlv_stream.write(&mut encoded_offer).unwrap();
1279
1280                 if let Err(e) = Offer::try_from(encoded_offer) {
1281                         panic!("error parsing offer: {:?}", e);
1282                 }
1283
1284                 let mut tlv_stream = offer.as_tlv_stream();
1285                 tlv_stream.amount = None;
1286                 tlv_stream.currency = Some(b"USD");
1287
1288                 let mut encoded_offer = Vec::new();
1289                 tlv_stream.write(&mut encoded_offer).unwrap();
1290
1291                 match Offer::try_from(encoded_offer) {
1292                         Ok(_) => panic!("expected error"),
1293                         Err(e) => assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingAmount)),
1294                 }
1295
1296                 let mut tlv_stream = offer.as_tlv_stream();
1297                 tlv_stream.amount = Some(MAX_VALUE_MSAT + 1);
1298                 tlv_stream.currency = None;
1299
1300                 let mut encoded_offer = Vec::new();
1301                 tlv_stream.write(&mut encoded_offer).unwrap();
1302
1303                 match Offer::try_from(encoded_offer) {
1304                         Ok(_) => panic!("expected error"),
1305                         Err(e) => assert_eq!(e, ParseError::InvalidSemantics(SemanticError::InvalidAmount)),
1306                 }
1307         }
1308
1309         #[test]
1310         fn parses_offer_with_description() {
1311                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1312                 if let Err(e) = offer.to_string().parse::<Offer>() {
1313                         panic!("error parsing offer: {:?}", e);
1314                 }
1315
1316                 let mut tlv_stream = offer.as_tlv_stream();
1317                 tlv_stream.description = None;
1318
1319                 let mut encoded_offer = Vec::new();
1320                 tlv_stream.write(&mut encoded_offer).unwrap();
1321
1322                 match Offer::try_from(encoded_offer) {
1323                         Ok(_) => panic!("expected error"),
1324                         Err(e) => {
1325                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingDescription));
1326                         },
1327                 }
1328         }
1329
1330         #[test]
1331         fn parses_offer_with_paths() {
1332                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1333                         .path(BlindedPath {
1334                                 introduction_node_id: pubkey(40),
1335                                 blinding_point: pubkey(41),
1336                                 blinded_hops: vec![
1337                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1338                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1339                                 ],
1340                         })
1341                         .path(BlindedPath {
1342                                 introduction_node_id: pubkey(40),
1343                                 blinding_point: pubkey(41),
1344                                 blinded_hops: vec![
1345                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1346                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1347                                 ],
1348                         })
1349                         .build()
1350                         .unwrap();
1351                 if let Err(e) = offer.to_string().parse::<Offer>() {
1352                         panic!("error parsing offer: {:?}", e);
1353                 }
1354
1355                 let mut builder = OfferBuilder::new("foo".into(), pubkey(42));
1356                 builder.offer.paths = Some(vec![]);
1357
1358                 let offer = builder.build().unwrap();
1359                 if let Err(e) = offer.to_string().parse::<Offer>() {
1360                         panic!("error parsing offer: {:?}", e);
1361                 }
1362         }
1363
1364         #[test]
1365         fn parses_offer_with_quantity() {
1366                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1367                         .supported_quantity(Quantity::One)
1368                         .build()
1369                         .unwrap();
1370                 if let Err(e) = offer.to_string().parse::<Offer>() {
1371                         panic!("error parsing offer: {:?}", e);
1372                 }
1373
1374                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1375                         .supported_quantity(Quantity::Unbounded)
1376                         .build()
1377                         .unwrap();
1378                 if let Err(e) = offer.to_string().parse::<Offer>() {
1379                         panic!("error parsing offer: {:?}", e);
1380                 }
1381
1382                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1383                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(10).unwrap()))
1384                         .build()
1385                         .unwrap();
1386                 if let Err(e) = offer.to_string().parse::<Offer>() {
1387                         panic!("error parsing offer: {:?}", e);
1388                 }
1389
1390                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1391                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(1).unwrap()))
1392                         .build()
1393                         .unwrap();
1394                 if let Err(e) = offer.to_string().parse::<Offer>() {
1395                         panic!("error parsing offer: {:?}", e);
1396                 }
1397         }
1398
1399         #[test]
1400         fn parses_offer_with_node_id() {
1401                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1402                 if let Err(e) = offer.to_string().parse::<Offer>() {
1403                         panic!("error parsing offer: {:?}", e);
1404                 }
1405
1406                 let mut tlv_stream = offer.as_tlv_stream();
1407                 tlv_stream.node_id = None;
1408
1409                 let mut encoded_offer = Vec::new();
1410                 tlv_stream.write(&mut encoded_offer).unwrap();
1411
1412                 match Offer::try_from(encoded_offer) {
1413                         Ok(_) => panic!("expected error"),
1414                         Err(e) => {
1415                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingSigningPubkey));
1416                         },
1417                 }
1418         }
1419
1420         #[test]
1421         fn fails_parsing_offer_with_extra_tlv_records() {
1422                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1423
1424                 let mut encoded_offer = Vec::new();
1425                 offer.write(&mut encoded_offer).unwrap();
1426                 BigSize(80).write(&mut encoded_offer).unwrap();
1427                 BigSize(32).write(&mut encoded_offer).unwrap();
1428                 [42u8; 32].write(&mut encoded_offer).unwrap();
1429
1430                 match Offer::try_from(encoded_offer) {
1431                         Ok(_) => panic!("expected error"),
1432                         Err(e) => assert_eq!(e, ParseError::Decode(DecodeError::InvalidValue)),
1433                 }
1434         }
1435 }
1436
1437 #[cfg(test)]
1438 mod bech32_tests {
1439         use super::{Offer, ParseError};
1440         use bitcoin::bech32;
1441         use crate::ln::msgs::DecodeError;
1442
1443         // TODO: Remove once test vectors are updated.
1444         #[ignore]
1445         #[test]
1446         fn encodes_offer_as_bech32_without_checksum() {
1447                 let encoded_offer = "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy";
1448                 let offer = dbg!(encoded_offer.parse::<Offer>().unwrap());
1449                 let reencoded_offer = offer.to_string();
1450                 dbg!(reencoded_offer.parse::<Offer>().unwrap());
1451                 assert_eq!(reencoded_offer, encoded_offer);
1452         }
1453
1454         // TODO: Remove once test vectors are updated.
1455         #[ignore]
1456         #[test]
1457         fn parses_bech32_encoded_offers() {
1458                 let offers = [
1459                         // BOLT 12 test vectors
1460                         "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1461                         "l+no1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1462                         "l+no1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1463                         "lno1qcp4256ypqpq+86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn0+0fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0+sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qs+y",
1464                         "lno1qcp4256ypqpq+ 86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn0+  0fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0+\nsqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43l+\r\nastpwuh73k29qs+\r  y",
1465                         // Two blinded paths
1466                         "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",
1467                 ];
1468                 for encoded_offer in &offers {
1469                         if let Err(e) = encoded_offer.parse::<Offer>() {
1470                                 panic!("Invalid offer ({:?}): {}", e, encoded_offer);
1471                         }
1472                 }
1473         }
1474
1475         #[test]
1476         fn fails_parsing_bech32_encoded_offers_with_invalid_continuations() {
1477                 let offers = [
1478                         // BOLT 12 test vectors
1479                         "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy+",
1480                         "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy+ ",
1481                         "+lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1482                         "+ lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1483                         "ln++o1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1484                 ];
1485                 for encoded_offer in &offers {
1486                         match encoded_offer.parse::<Offer>() {
1487                                 Ok(_) => panic!("Valid offer: {}", encoded_offer),
1488                                 Err(e) => assert_eq!(e, ParseError::InvalidContinuation),
1489                         }
1490                 }
1491
1492         }
1493
1494         #[test]
1495         fn fails_parsing_bech32_encoded_offer_with_invalid_hrp() {
1496                 let encoded_offer = "lni1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy";
1497                 match encoded_offer.parse::<Offer>() {
1498                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1499                         Err(e) => assert_eq!(e, ParseError::InvalidBech32Hrp),
1500                 }
1501         }
1502
1503         #[test]
1504         fn fails_parsing_bech32_encoded_offer_with_invalid_bech32_data() {
1505                 let encoded_offer = "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qso";
1506                 match encoded_offer.parse::<Offer>() {
1507                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1508                         Err(e) => assert_eq!(e, ParseError::Bech32(bech32::Error::InvalidChar('o'))),
1509                 }
1510         }
1511
1512         #[test]
1513         fn fails_parsing_bech32_encoded_offer_with_invalid_tlv_data() {
1514                 let encoded_offer = "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsyqqqqq";
1515                 match encoded_offer.parse::<Offer>() {
1516                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1517                         Err(e) => assert_eq!(e, ParseError::Decode(DecodeError::InvalidValue)),
1518                 }
1519         }
1520 }