_ 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::{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::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 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         /// Creates an [`InvoiceRequest`] for the offer with the given `metadata` and `payer_id`, which
 443         /// will be reflected in the `Invoice` response.
 444         ///
 445         /// The `metadata` is useful for including information about the derivation of `payer_id` such
 446         /// that invoice response handling can be stateless. Also serves as payer-provided entropy while
 447         /// hashing in the signature calculation.
 448         ///
 449         /// This should not leak any information such as by using a simple BIP-32 derivation path.
 450         /// Otherwise, payments may be correlated.
 451         ///
 452         /// Errors if the offer contains unknown required features.
 453         ///
 454         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 455         pub fn request_invoice(
 456                 &self, metadata: Vec<u8>, payer_id: PublicKey
 457         ) -> Result<InvoiceRequestBuilder, SemanticError> {
 458                 if self.features().requires_unknown_bits() {
 459                         return Err(SemanticError::UnknownRequiredFeatures);
 460                 }
 461
 462                 Ok(InvoiceRequestBuilder::new(self, metadata, payer_id))
 463         }
 464
 465         #[cfg(test)]
 466         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 467                 self.contents.as_tlv_stream()
 468         }
 469 }
 470
 471 impl AsRef<[u8]> for Offer {
 472         fn as_ref(&self) -> &[u8] {
 473                 &self.bytes
 474         }
 475 }
 476
 477 impl OfferContents {
 478         pub fn chains(&self) -> Vec<ChainHash> {
 479                 self.chains.as_ref().cloned().unwrap_or_else(|| vec![self.implied_chain()])
 480         }
 481
 482         pub fn implied_chain(&self) -> ChainHash {
 483                 ChainHash::using_genesis_block(Network::Bitcoin)
 484         }
 485
 486         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 487                 self.chains().contains(&chain)
 488         }
 489
 490         pub fn metadata(&self) -> Option<&Vec<u8>> {
 491                 self.metadata.as_ref().and_then(|metadata| metadata.as_bytes())
 492         }
 493
 494         #[cfg(feature = "std")]
 495         pub(super) fn is_expired(&self) -> bool {
 496                 match self.absolute_expiry {
 497                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
 498                                 Ok(elapsed) => elapsed > seconds_from_epoch,
 499                                 Err(_) => false,
 500                         },
 501                         None => false,
 502                 }
 503         }
 504
 505         pub fn amount(&self) -> Option<&Amount> {
 506                 self.amount.as_ref()
 507         }
 508
 509         pub(super) fn check_amount_msats_for_quantity(
 510                 &self, amount_msats: Option<u64>, quantity: Option<u64>
 511         ) -> Result<(), SemanticError> {
 512                 let offer_amount_msats = match self.amount {
 513                         None => 0,
 514                         Some(Amount::Bitcoin { amount_msats }) => amount_msats,
 515                         Some(Amount::Currency { .. }) => return Err(SemanticError::UnsupportedCurrency),
 516                 };
 517
 518                 if !self.expects_quantity() || quantity.is_some() {
 519                         let expected_amount_msats = offer_amount_msats.checked_mul(quantity.unwrap_or(1))
 520                                 .ok_or(SemanticError::InvalidAmount)?;
 521                         let amount_msats = amount_msats.unwrap_or(expected_amount_msats);
 522
 523                         if amount_msats < expected_amount_msats {
 524                                 return Err(SemanticError::InsufficientAmount);
 525                         }
 526
 527                         if amount_msats > MAX_VALUE_MSAT {
 528                                 return Err(SemanticError::InvalidAmount);
 529                         }
 530                 }
 531
 532                 Ok(())
 533         }
 534
 535         pub fn supported_quantity(&self) -> Quantity {
 536                 self.supported_quantity
 537         }
 538
 539         pub(super) fn check_quantity(&self, quantity: Option<u64>) -> Result<(), SemanticError> {
 540                 let expects_quantity = self.expects_quantity();
 541                 match quantity {
 542                         None if expects_quantity => Err(SemanticError::MissingQuantity),
 543                         Some(_) if !expects_quantity => Err(SemanticError::UnexpectedQuantity),
 544                         Some(quantity) if !self.is_valid_quantity(quantity) => {
 545                                 Err(SemanticError::InvalidQuantity)
 546                         },
 547                         _ => Ok(()),
 548                 }
 549         }
 550
 551         fn is_valid_quantity(&self, quantity: u64) -> bool {
 552                 match self.supported_quantity {
 553                         Quantity::Bounded(n) => quantity <= n.get(),
 554                         Quantity::Unbounded => quantity > 0,
 555                         Quantity::One => quantity == 1,
 556                 }
 557         }
 558
 559         fn expects_quantity(&self) -> bool {
 560                 match self.supported_quantity {
 561                         Quantity::Bounded(_) => true,
 562                         Quantity::Unbounded => true,
 563                         Quantity::One => false,
 564                 }
 565         }
 566
 567         pub(super) fn signing_pubkey(&self) -> PublicKey {
 568                 self.signing_pubkey
 569         }
 570
 571         /// Verifies that the offer metadata was produced from the offer in the TLV stream.
 572         pub(super) fn verify<T: secp256k1::Signing>(
 573                 &self, tlv_stream: TlvStream<'_>, key: &ExpandedKey, secp_ctx: &Secp256k1<T>
 574         ) -> bool {
 575                 match self.metadata() {
 576                         Some(metadata) => {
 577                                 let tlv_stream = tlv_stream.range(OFFER_TYPES).filter(|record| {
 578                                         match record.r#type {
 579                                                 OFFER_METADATA_TYPE => false,
 580                                                 OFFER_NODE_ID_TYPE => !self.metadata.as_ref().unwrap().derives_keys(),
 581                                                 _ => true,
 582                                         }
 583                                 });
 584                                 signer::verify_metadata(
 585                                         metadata, key, IV_BYTES, self.signing_pubkey(), tlv_stream, secp_ctx
 586                                 )
 587                         },
 588                         None => false,
 589                 }
 590         }
 591
 592         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 593                 let (currency, amount) = match &self.amount {
 594                         None => (None, None),
 595                         Some(Amount::Bitcoin { amount_msats }) => (None, Some(*amount_msats)),
 596                         Some(Amount::Currency { iso4217_code, amount }) => (
 597                                 Some(iso4217_code), Some(*amount)
 598                         ),
 599                 };
 600
 601                 let features = {
 602                         if self.features == OfferFeatures::empty() { None } else { Some(&self.features) }
 603                 };
 604
 605                 OfferTlvStreamRef {
 606                         chains: self.chains.as_ref(),
 607                         metadata: self.metadata(),
 608                         currency,
 609                         amount,
 610                         description: Some(&self.description),
 611                         features,
 612                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 613                         paths: self.paths.as_ref(),
 614                         issuer: self.issuer.as_ref(),
 615                         quantity_max: self.supported_quantity.to_tlv_record(),
 616                         node_id: Some(&self.signing_pubkey),
 617                 }
 618         }
 619 }
 620
 621 impl Writeable for Offer {
 622         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 623                 WithoutLength(&self.bytes).write(writer)
 624         }
 625 }
 626
 627 impl Writeable for OfferContents {
 628         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 629                 self.as_tlv_stream().write(writer)
 630         }
 631 }
 632
 633 /// The minimum amount required for an item in an [`Offer`], denominated in either bitcoin or
 634 /// another currency.
 635 #[derive(Clone, Debug, PartialEq)]
 636 pub enum Amount {
 637         /// An amount of bitcoin.
 638         Bitcoin {
 639                 /// The amount in millisatoshi.
 640                 amount_msats: u64,
 641         },
 642         /// An amount of currency specified using ISO 4712.
 643         Currency {
 644                 /// The currency that the amount is denominated in.
 645                 iso4217_code: CurrencyCode,
 646                 /// The amount in the currency unit adjusted by the ISO 4712 exponent (e.g., USD cents).
 647                 amount: u64,
 648         },
 649 }
 650
 651 /// An ISO 4712 three-letter currency code (e.g., USD).
 652 pub type CurrencyCode = [u8; 3];
 653
 654 /// Quantity of items supported by an [`Offer`].
 655 #[derive(Clone, Copy, Debug, PartialEq)]
 656 pub enum Quantity {
 657         /// Up to a specific number of items (inclusive). Use when more than one item can be requested
 658         /// but is limited (e.g., because of per customer or inventory limits).
 659         ///
 660         /// May be used with `NonZeroU64::new(1)` but prefer to use [`Quantity::One`] if only one item
 661         /// is supported.
 662         Bounded(NonZeroU64),
 663         /// One or more items. Use when more than one item can be requested without any limit.
 664         Unbounded,
 665         /// Only one item. Use when only a single item can be requested.
 666         One,
 667 }
 668
 669 impl Quantity {
 670         fn to_tlv_record(&self) -> Option<u64> {
 671                 match self {
 672                         Quantity::Bounded(n) => Some(n.get()),
 673                         Quantity::Unbounded => Some(0),
 674                         Quantity::One => None,
 675                 }
 676         }
 677 }
 678
 679 /// Valid type range for offer TLV records.
 680 const OFFER_TYPES: core::ops::Range<u64> = 1..80;
 681
 682 /// TLV record type for [`Offer::metadata`].
 683 const OFFER_METADATA_TYPE: u64 = 4;
 684
 685 /// TLV record type for [`Offer::signing_pubkey`].
 686 const OFFER_NODE_ID_TYPE: u64 = 22;
 687
 688 tlv_stream!(OfferTlvStream, OfferTlvStreamRef, OFFER_TYPES, {
 689         (2, chains: (Vec<ChainHash>, WithoutLength)),
 690         (OFFER_METADATA_TYPE, metadata: (Vec<u8>, WithoutLength)),
 691         (6, currency: CurrencyCode),
 692         (8, amount: (u64, HighZeroBytesDroppedBigSize)),
 693         (10, description: (String, WithoutLength)),
 694         (12, features: (OfferFeatures, WithoutLength)),
 695         (14, absolute_expiry: (u64, HighZeroBytesDroppedBigSize)),
 696         (16, paths: (Vec<BlindedPath>, WithoutLength)),
 697         (18, issuer: (String, WithoutLength)),
 698         (20, quantity_max: (u64, HighZeroBytesDroppedBigSize)),
 699         (OFFER_NODE_ID_TYPE, node_id: PublicKey),
 700 });
 701
 702 impl Bech32Encode for Offer {
 703         const BECH32_HRP: &'static str = "lno";
 704 }
 705
 706 impl FromStr for Offer {
 707         type Err = ParseError;
 708
 709         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 710                 Self::from_bech32_str(s)
 711         }
 712 }
 713
 714 impl TryFrom<Vec<u8>> for Offer {
 715         type Error = ParseError;
 716
 717         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 718                 let offer = ParsedMessage::<OfferTlvStream>::try_from(bytes)?;
 719                 let ParsedMessage { bytes, tlv_stream } = offer;
 720                 let contents = OfferContents::try_from(tlv_stream)?;
 721                 Ok(Offer { bytes, contents })
 722         }
 723 }
 724
 725 impl TryFrom<OfferTlvStream> for OfferContents {
 726         type Error = SemanticError;
 727
 728         fn try_from(tlv_stream: OfferTlvStream) -> Result<Self, Self::Error> {
 729                 let OfferTlvStream {
 730                         chains, metadata, currency, amount, description, features, absolute_expiry, paths,
 731                         issuer, quantity_max, node_id,
 732                 } = tlv_stream;
 733
 734                 let metadata = metadata.map(|metadata| Metadata::Bytes(metadata));
 735
 736                 let amount = match (currency, amount) {
 737                         (None, None) => None,
 738                         (None, Some(amount_msats)) if amount_msats > MAX_VALUE_MSAT => {
 739                                 return Err(SemanticError::InvalidAmount);
 740                         },
 741                         (None, Some(amount_msats)) => Some(Amount::Bitcoin { amount_msats }),
 742                         (Some(_), None) => return Err(SemanticError::MissingAmount),
 743                         (Some(iso4217_code), Some(amount)) => Some(Amount::Currency { iso4217_code, amount }),
 744                 };
 745
 746                 let description = match description {
 747                         None => return Err(SemanticError::MissingDescription),
 748                         Some(description) => description,
 749                 };
 750
 751                 let features = features.unwrap_or_else(OfferFeatures::empty);
 752
 753                 let absolute_expiry = absolute_expiry
 754                         .map(|seconds_from_epoch| Duration::from_secs(seconds_from_epoch));
 755
 756                 let supported_quantity = match quantity_max {
 757                         None => Quantity::One,
 758                         Some(0) => Quantity::Unbounded,
 759                         Some(n) => Quantity::Bounded(NonZeroU64::new(n).unwrap()),
 760                 };
 761
 762                 let signing_pubkey = match node_id {
 763                         None => return Err(SemanticError::MissingSigningPubkey),
 764                         Some(node_id) => node_id,
 765                 };
 766
 767                 Ok(OfferContents {
 768                         chains, metadata, amount, description, features, absolute_expiry, issuer, paths,
 769                         supported_quantity, signing_pubkey,
 770                 })
 771         }
 772 }
 773
 774 impl core::fmt::Display for Offer {
 775         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 776                 self.fmt_bech32_str(f)
 777         }
 778 }
 779
 780 #[cfg(test)]
 781 mod tests {
 782         use super::{Amount, Offer, OfferBuilder, OfferTlvStreamRef, Quantity};
 783
 784         use bitcoin::blockdata::constants::ChainHash;
 785         use bitcoin::network::constants::Network;
 786         use bitcoin::secp256k1::Secp256k1;
 787         use core::convert::TryFrom;
 788         use core::num::NonZeroU64;
 789         use core::time::Duration;
 790         use crate::chain::keysinterface::KeyMaterial;
 791         use crate::ln::features::OfferFeatures;
 792         use crate::ln::inbound_payment::ExpandedKey;
 793         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 794         use crate::offers::parse::{ParseError, SemanticError};
 795         use crate::offers::test_utils::*;
 796         use crate::onion_message::{BlindedHop, BlindedPath};
 797         use crate::util::ser::{BigSize, Writeable};
 798         use crate::util::string::PrintableString;
 799
 800         #[test]
 801         fn builds_offer_with_defaults() {
 802                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
 803
 804                 let mut buffer = Vec::new();
 805                 offer.write(&mut buffer).unwrap();
 806
 807                 assert_eq!(offer.bytes, buffer.as_slice());
 808                 assert_eq!(offer.chains(), vec![ChainHash::using_genesis_block(Network::Bitcoin)]);
 809                 assert!(offer.supports_chain(ChainHash::using_genesis_block(Network::Bitcoin)));
 810                 assert_eq!(offer.metadata(), None);
 811                 assert_eq!(offer.amount(), None);
 812                 assert_eq!(offer.description(), PrintableString("foo"));
 813                 assert_eq!(offer.features(), &OfferFeatures::empty());
 814                 assert_eq!(offer.absolute_expiry(), None);
 815                 #[cfg(feature = "std")]
 816                 assert!(!offer.is_expired());
 817                 assert_eq!(offer.paths(), &[]);
 818                 assert_eq!(offer.issuer(), None);
 819                 assert_eq!(offer.supported_quantity(), Quantity::One);
 820                 assert_eq!(offer.signing_pubkey(), pubkey(42));
 821
 822                 assert_eq!(
 823                         offer.as_tlv_stream(),
 824                         OfferTlvStreamRef {
 825                                 chains: None,
 826                                 metadata: None,
 827                                 currency: None,
 828                                 amount: None,
 829                                 description: Some(&String::from("foo")),
 830                                 features: None,
 831                                 absolute_expiry: None,
 832                                 paths: None,
 833                                 issuer: None,
 834                                 quantity_max: None,
 835                                 node_id: Some(&pubkey(42)),
 836                         },
 837                 );
 838
 839                 if let Err(e) = Offer::try_from(buffer) {
 840                         panic!("error parsing offer: {:?}", e);
 841                 }
 842         }
 843
 844         #[test]
 845         fn builds_offer_with_chains() {
 846                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
 847                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
 848
 849                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 850                         .chain(Network::Bitcoin)
 851                         .build()
 852                         .unwrap();
 853                 assert!(offer.supports_chain(mainnet));
 854                 assert_eq!(offer.chains(), vec![mainnet]);
 855                 assert_eq!(offer.as_tlv_stream().chains, None);
 856
 857                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 858                         .chain(Network::Testnet)
 859                         .build()
 860                         .unwrap();
 861                 assert!(offer.supports_chain(testnet));
 862                 assert_eq!(offer.chains(), vec![testnet]);
 863                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 864
 865                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 866                         .chain(Network::Testnet)
 867                         .chain(Network::Testnet)
 868                         .build()
 869                         .unwrap();
 870                 assert!(offer.supports_chain(testnet));
 871                 assert_eq!(offer.chains(), vec![testnet]);
 872                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 873
 874                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 875                         .chain(Network::Bitcoin)
 876                         .chain(Network::Testnet)
 877                         .build()
 878                         .unwrap();
 879                 assert!(offer.supports_chain(mainnet));
 880                 assert!(offer.supports_chain(testnet));
 881                 assert_eq!(offer.chains(), vec![mainnet, testnet]);
 882                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![mainnet, testnet]));
 883         }
 884
 885         #[test]
 886         fn builds_offer_with_metadata() {
 887                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 888                         .metadata(vec![42; 32]).unwrap()
 889                         .build()
 890                         .unwrap();
 891                 assert_eq!(offer.metadata(), Some(&vec![42; 32]));
 892                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![42; 32]));
 893
 894                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 895                         .metadata(vec![42; 32]).unwrap()
 896                         .metadata(vec![43; 32]).unwrap()
 897                         .build()
 898                         .unwrap();
 899                 assert_eq!(offer.metadata(), Some(&vec![43; 32]));
 900                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![43; 32]));
 901         }
 902
 903         #[test]
 904         fn builds_offer_with_metadata_derived() {
 905                 let desc = "foo".to_string();
 906                 let node_id = recipient_pubkey();
 907                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
 908                 let entropy = FixedEntropy {};
 909                 let secp_ctx = Secp256k1::new();
 910
 911                 let offer = OfferBuilder
 912                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
 913                         .amount_msats(1000)
 914                         .build().unwrap();
 915                 assert_eq!(offer.signing_pubkey(), node_id);
 916
 917                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 918                         .build().unwrap()
 919                         .sign(payer_sign).unwrap();
 920                 assert!(invoice_request.verify(&expanded_key, &secp_ctx));
 921
 922                 // Fails verification with altered offer field
 923                 let mut tlv_stream = offer.as_tlv_stream();
 924                 tlv_stream.amount = Some(100);
 925
 926                 let mut encoded_offer = Vec::new();
 927                 tlv_stream.write(&mut encoded_offer).unwrap();
 928
 929                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
 930                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 931                         .build().unwrap()
 932                         .sign(payer_sign).unwrap();
 933                 assert!(!invoice_request.verify(&expanded_key, &secp_ctx));
 934
 935                 // Fails verification with altered metadata
 936                 let mut tlv_stream = offer.as_tlv_stream();
 937                 let metadata = tlv_stream.metadata.unwrap().iter().copied().rev().collect();
 938                 tlv_stream.metadata = Some(&metadata);
 939
 940                 let mut encoded_offer = Vec::new();
 941                 tlv_stream.write(&mut encoded_offer).unwrap();
 942
 943                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
 944                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 945                         .build().unwrap()
 946                         .sign(payer_sign).unwrap();
 947                 assert!(!invoice_request.verify(&expanded_key, &secp_ctx));
 948         }
 949
 950         #[test]
 951         fn builds_offer_with_derived_signing_pubkey() {
 952                 let desc = "foo".to_string();
 953                 let node_id = recipient_pubkey();
 954                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
 955                 let entropy = FixedEntropy {};
 956                 let secp_ctx = Secp256k1::new();
 957
 958                 let blinded_path = BlindedPath {
 959                         introduction_node_id: pubkey(40),
 960                         blinding_point: pubkey(41),
 961                         blinded_hops: vec![
 962                                 BlindedHop { blinded_node_id: pubkey(42), encrypted_payload: vec![0; 43] },
 963                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
 964                         ],
 965                 };
 966
 967                 let offer = OfferBuilder
 968                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
 969                         .amount_msats(1000)
 970                         .path(blinded_path)
 971                         .build().unwrap();
 972                 assert_ne!(offer.signing_pubkey(), node_id);
 973
 974                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 975                         .build().unwrap()
 976                         .sign(payer_sign).unwrap();
 977                 assert!(invoice_request.verify(&expanded_key, &secp_ctx));
 978
 979                 // Fails verification with altered offer field
 980                 let mut tlv_stream = offer.as_tlv_stream();
 981                 tlv_stream.amount = Some(100);
 982
 983                 let mut encoded_offer = Vec::new();
 984                 tlv_stream.write(&mut encoded_offer).unwrap();
 985
 986                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
 987                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 988                         .build().unwrap()
 989                         .sign(payer_sign).unwrap();
 990                 assert!(!invoice_request.verify(&expanded_key, &secp_ctx));
 991
 992                 // Fails verification with altered signing pubkey
 993                 let mut tlv_stream = offer.as_tlv_stream();
 994                 let signing_pubkey = pubkey(1);
 995                 tlv_stream.node_id = Some(&signing_pubkey);
 996
 997                 let mut encoded_offer = Vec::new();
 998                 tlv_stream.write(&mut encoded_offer).unwrap();
 999
1000                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1001                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1002                         .build().unwrap()
1003                         .sign(payer_sign).unwrap();
1004                 assert!(!invoice_request.verify(&expanded_key, &secp_ctx));
1005         }
1006
1007         #[test]
1008         fn builds_offer_with_amount() {
1009                 let bitcoin_amount = Amount::Bitcoin { amount_msats: 1000 };
1010                 let currency_amount = Amount::Currency { iso4217_code: *b"USD", amount: 10 };
1011
1012                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1013                         .amount_msats(1000)
1014                         .build()
1015                         .unwrap();
1016                 let tlv_stream = offer.as_tlv_stream();
1017                 assert_eq!(offer.amount(), Some(&bitcoin_amount));
1018                 assert_eq!(tlv_stream.amount, Some(1000));
1019                 assert_eq!(tlv_stream.currency, None);
1020
1021                 let builder = OfferBuilder::new("foo".into(), pubkey(42))
1022                         .amount(currency_amount.clone());
1023                 let tlv_stream = builder.offer.as_tlv_stream();
1024                 assert_eq!(builder.offer.amount, Some(currency_amount.clone()));
1025                 assert_eq!(tlv_stream.amount, Some(10));
1026                 assert_eq!(tlv_stream.currency, Some(b"USD"));
1027                 match builder.build() {
1028                         Ok(_) => panic!("expected error"),
1029                         Err(e) => assert_eq!(e, SemanticError::UnsupportedCurrency),
1030                 }
1031
1032                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1033                         .amount(currency_amount.clone())
1034                         .amount(bitcoin_amount.clone())
1035                         .build()
1036                         .unwrap();
1037                 let tlv_stream = offer.as_tlv_stream();
1038                 assert_eq!(tlv_stream.amount, Some(1000));
1039                 assert_eq!(tlv_stream.currency, None);
1040
1041                 let invalid_amount = Amount::Bitcoin { amount_msats: MAX_VALUE_MSAT + 1 };
1042                 match OfferBuilder::new("foo".into(), pubkey(42)).amount(invalid_amount).build() {
1043                         Ok(_) => panic!("expected error"),
1044                         Err(e) => assert_eq!(e, SemanticError::InvalidAmount),
1045                 }
1046         }
1047
1048         #[test]
1049         fn builds_offer_with_features() {
1050                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1051                         .features_unchecked(OfferFeatures::unknown())
1052                         .build()
1053                         .unwrap();
1054                 assert_eq!(offer.features(), &OfferFeatures::unknown());
1055                 assert_eq!(offer.as_tlv_stream().features, Some(&OfferFeatures::unknown()));
1056
1057                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1058                         .features_unchecked(OfferFeatures::unknown())
1059                         .features_unchecked(OfferFeatures::empty())
1060                         .build()
1061                         .unwrap();
1062                 assert_eq!(offer.features(), &OfferFeatures::empty());
1063                 assert_eq!(offer.as_tlv_stream().features, None);
1064         }
1065
1066         #[test]
1067         fn builds_offer_with_absolute_expiry() {
1068                 let future_expiry = Duration::from_secs(u64::max_value());
1069                 let past_expiry = Duration::from_secs(0);
1070
1071                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1072                         .absolute_expiry(future_expiry)
1073                         .build()
1074                         .unwrap();
1075                 #[cfg(feature = "std")]
1076                 assert!(!offer.is_expired());
1077                 assert_eq!(offer.absolute_expiry(), Some(future_expiry));
1078                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(future_expiry.as_secs()));
1079
1080                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1081                         .absolute_expiry(future_expiry)
1082                         .absolute_expiry(past_expiry)
1083                         .build()
1084                         .unwrap();
1085                 #[cfg(feature = "std")]
1086                 assert!(offer.is_expired());
1087                 assert_eq!(offer.absolute_expiry(), Some(past_expiry));
1088                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(past_expiry.as_secs()));
1089         }
1090
1091         #[test]
1092         fn builds_offer_with_paths() {
1093                 let paths = vec![
1094                         BlindedPath {
1095                                 introduction_node_id: pubkey(40),
1096                                 blinding_point: pubkey(41),
1097                                 blinded_hops: vec![
1098                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1099                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1100                                 ],
1101                         },
1102                         BlindedPath {
1103                                 introduction_node_id: pubkey(40),
1104                                 blinding_point: pubkey(41),
1105                                 blinded_hops: vec![
1106                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1107                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1108                                 ],
1109                         },
1110                 ];
1111
1112                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1113                         .path(paths[0].clone())
1114                         .path(paths[1].clone())
1115                         .build()
1116                         .unwrap();
1117                 let tlv_stream = offer.as_tlv_stream();
1118                 assert_eq!(offer.paths(), paths.as_slice());
1119                 assert_eq!(offer.signing_pubkey(), pubkey(42));
1120                 assert_ne!(pubkey(42), pubkey(44));
1121                 assert_eq!(tlv_stream.paths, Some(&paths));
1122                 assert_eq!(tlv_stream.node_id, Some(&pubkey(42)));
1123         }
1124
1125         #[test]
1126         fn builds_offer_with_issuer() {
1127                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1128                         .issuer("bar".into())
1129                         .build()
1130                         .unwrap();
1131                 assert_eq!(offer.issuer(), Some(PrintableString("bar")));
1132                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("bar")));
1133
1134                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1135                         .issuer("bar".into())
1136                         .issuer("baz".into())
1137                         .build()
1138                         .unwrap();
1139                 assert_eq!(offer.issuer(), Some(PrintableString("baz")));
1140                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("baz")));
1141         }
1142
1143         #[test]
1144         fn builds_offer_with_supported_quantity() {
1145                 let one = NonZeroU64::new(1).unwrap();
1146                 let ten = NonZeroU64::new(10).unwrap();
1147
1148                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1149                         .supported_quantity(Quantity::One)
1150                         .build()
1151                         .unwrap();
1152                 let tlv_stream = offer.as_tlv_stream();
1153                 assert_eq!(offer.supported_quantity(), Quantity::One);
1154                 assert_eq!(tlv_stream.quantity_max, None);
1155
1156                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1157                         .supported_quantity(Quantity::Unbounded)
1158                         .build()
1159                         .unwrap();
1160                 let tlv_stream = offer.as_tlv_stream();
1161                 assert_eq!(offer.supported_quantity(), Quantity::Unbounded);
1162                 assert_eq!(tlv_stream.quantity_max, Some(0));
1163
1164                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1165                         .supported_quantity(Quantity::Bounded(ten))
1166                         .build()
1167                         .unwrap();
1168                 let tlv_stream = offer.as_tlv_stream();
1169                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(ten));
1170                 assert_eq!(tlv_stream.quantity_max, Some(10));
1171
1172                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1173                         .supported_quantity(Quantity::Bounded(one))
1174                         .build()
1175                         .unwrap();
1176                 let tlv_stream = offer.as_tlv_stream();
1177                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(one));
1178                 assert_eq!(tlv_stream.quantity_max, Some(1));
1179
1180                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1181                         .supported_quantity(Quantity::Bounded(ten))
1182                         .supported_quantity(Quantity::One)
1183                         .build()
1184                         .unwrap();
1185                 let tlv_stream = offer.as_tlv_stream();
1186                 assert_eq!(offer.supported_quantity(), Quantity::One);
1187                 assert_eq!(tlv_stream.quantity_max, None);
1188         }
1189
1190         #[test]
1191         fn fails_requesting_invoice_with_unknown_required_features() {
1192                 match OfferBuilder::new("foo".into(), pubkey(42))
1193                         .features_unchecked(OfferFeatures::unknown())
1194                         .build().unwrap()
1195                         .request_invoice(vec![1; 32], pubkey(43))
1196                 {
1197                         Ok(_) => panic!("expected error"),
1198                         Err(e) => assert_eq!(e, SemanticError::UnknownRequiredFeatures),
1199                 }
1200         }
1201
1202         #[test]
1203         fn parses_offer_with_chains() {
1204                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1205                         .chain(Network::Bitcoin)
1206                         .chain(Network::Testnet)
1207                         .build()
1208                         .unwrap();
1209                 if let Err(e) = offer.to_string().parse::<Offer>() {
1210                         panic!("error parsing offer: {:?}", e);
1211                 }
1212         }
1213
1214         #[test]
1215         fn parses_offer_with_amount() {
1216                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1217                         .amount(Amount::Bitcoin { amount_msats: 1000 })
1218                         .build()
1219                         .unwrap();
1220                 if let Err(e) = offer.to_string().parse::<Offer>() {
1221                         panic!("error parsing offer: {:?}", e);
1222                 }
1223
1224                 let mut tlv_stream = offer.as_tlv_stream();
1225                 tlv_stream.amount = Some(1000);
1226                 tlv_stream.currency = Some(b"USD");
1227
1228                 let mut encoded_offer = Vec::new();
1229                 tlv_stream.write(&mut encoded_offer).unwrap();
1230
1231                 if let Err(e) = Offer::try_from(encoded_offer) {
1232                         panic!("error parsing offer: {:?}", e);
1233                 }
1234
1235                 let mut tlv_stream = offer.as_tlv_stream();
1236                 tlv_stream.amount = None;
1237                 tlv_stream.currency = Some(b"USD");
1238
1239                 let mut encoded_offer = Vec::new();
1240                 tlv_stream.write(&mut encoded_offer).unwrap();
1241
1242                 match Offer::try_from(encoded_offer) {
1243                         Ok(_) => panic!("expected error"),
1244                         Err(e) => assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingAmount)),
1245                 }
1246
1247                 let mut tlv_stream = offer.as_tlv_stream();
1248                 tlv_stream.amount = Some(MAX_VALUE_MSAT + 1);
1249                 tlv_stream.currency = None;
1250
1251                 let mut encoded_offer = Vec::new();
1252                 tlv_stream.write(&mut encoded_offer).unwrap();
1253
1254                 match Offer::try_from(encoded_offer) {
1255                         Ok(_) => panic!("expected error"),
1256                         Err(e) => assert_eq!(e, ParseError::InvalidSemantics(SemanticError::InvalidAmount)),
1257                 }
1258         }
1259
1260         #[test]
1261         fn parses_offer_with_description() {
1262                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1263                 if let Err(e) = offer.to_string().parse::<Offer>() {
1264                         panic!("error parsing offer: {:?}", e);
1265                 }
1266
1267                 let mut tlv_stream = offer.as_tlv_stream();
1268                 tlv_stream.description = None;
1269
1270                 let mut encoded_offer = Vec::new();
1271                 tlv_stream.write(&mut encoded_offer).unwrap();
1272
1273                 match Offer::try_from(encoded_offer) {
1274                         Ok(_) => panic!("expected error"),
1275                         Err(e) => {
1276                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingDescription));
1277                         },
1278                 }
1279         }
1280
1281         #[test]
1282         fn parses_offer_with_paths() {
1283                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1284                         .path(BlindedPath {
1285                                 introduction_node_id: pubkey(40),
1286                                 blinding_point: pubkey(41),
1287                                 blinded_hops: vec![
1288                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1289                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1290                                 ],
1291                         })
1292                         .path(BlindedPath {
1293                                 introduction_node_id: pubkey(40),
1294                                 blinding_point: pubkey(41),
1295                                 blinded_hops: vec![
1296                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1297                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1298                                 ],
1299                         })
1300                         .build()
1301                         .unwrap();
1302                 if let Err(e) = offer.to_string().parse::<Offer>() {
1303                         panic!("error parsing offer: {:?}", e);
1304                 }
1305
1306                 let mut builder = OfferBuilder::new("foo".into(), pubkey(42));
1307                 builder.offer.paths = Some(vec![]);
1308
1309                 let offer = builder.build().unwrap();
1310                 if let Err(e) = offer.to_string().parse::<Offer>() {
1311                         panic!("error parsing offer: {:?}", e);
1312                 }
1313         }
1314
1315         #[test]
1316         fn parses_offer_with_quantity() {
1317                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1318                         .supported_quantity(Quantity::One)
1319                         .build()
1320                         .unwrap();
1321                 if let Err(e) = offer.to_string().parse::<Offer>() {
1322                         panic!("error parsing offer: {:?}", e);
1323                 }
1324
1325                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1326                         .supported_quantity(Quantity::Unbounded)
1327                         .build()
1328                         .unwrap();
1329                 if let Err(e) = offer.to_string().parse::<Offer>() {
1330                         panic!("error parsing offer: {:?}", e);
1331                 }
1332
1333                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1334                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(10).unwrap()))
1335                         .build()
1336                         .unwrap();
1337                 if let Err(e) = offer.to_string().parse::<Offer>() {
1338                         panic!("error parsing offer: {:?}", e);
1339                 }
1340
1341                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1342                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(1).unwrap()))
1343                         .build()
1344                         .unwrap();
1345                 if let Err(e) = offer.to_string().parse::<Offer>() {
1346                         panic!("error parsing offer: {:?}", e);
1347                 }
1348         }
1349
1350         #[test]
1351         fn parses_offer_with_node_id() {
1352                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1353                 if let Err(e) = offer.to_string().parse::<Offer>() {
1354                         panic!("error parsing offer: {:?}", e);
1355                 }
1356
1357                 let mut tlv_stream = offer.as_tlv_stream();
1358                 tlv_stream.node_id = None;
1359
1360                 let mut encoded_offer = Vec::new();
1361                 tlv_stream.write(&mut encoded_offer).unwrap();
1362
1363                 match Offer::try_from(encoded_offer) {
1364                         Ok(_) => panic!("expected error"),
1365                         Err(e) => {
1366                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingSigningPubkey));
1367                         },
1368                 }
1369         }
1370
1371         #[test]
1372         fn fails_parsing_offer_with_extra_tlv_records() {
1373                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1374
1375                 let mut encoded_offer = Vec::new();
1376                 offer.write(&mut encoded_offer).unwrap();
1377                 BigSize(80).write(&mut encoded_offer).unwrap();
1378                 BigSize(32).write(&mut encoded_offer).unwrap();
1379                 [42u8; 32].write(&mut encoded_offer).unwrap();
1380
1381                 match Offer::try_from(encoded_offer) {
1382                         Ok(_) => panic!("expected error"),
1383                         Err(e) => assert_eq!(e, ParseError::Decode(DecodeError::InvalidValue)),
1384                 }
1385         }
1386 }
1387
1388 #[cfg(test)]
1389 mod bech32_tests {
1390         use super::{Offer, ParseError};
1391         use bitcoin::bech32;
1392         use crate::ln::msgs::DecodeError;
1393
1394         // TODO: Remove once test vectors are updated.
1395         #[ignore]
1396         #[test]
1397         fn encodes_offer_as_bech32_without_checksum() {
1398                 let encoded_offer = "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy";
1399                 let offer = dbg!(encoded_offer.parse::<Offer>().unwrap());
1400                 let reencoded_offer = offer.to_string();
1401                 dbg!(reencoded_offer.parse::<Offer>().unwrap());
1402                 assert_eq!(reencoded_offer, encoded_offer);
1403         }
1404
1405         // TODO: Remove once test vectors are updated.
1406         #[ignore]
1407         #[test]
1408         fn parses_bech32_encoded_offers() {
1409                 let offers = [
1410                         // BOLT 12 test vectors
1411                         "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1412                         "l+no1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1413                         "l+no1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1414                         "lno1qcp4256ypqpq+86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn0+0fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0+sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qs+y",
1415                         "lno1qcp4256ypqpq+ 86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn0+  0fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0+\nsqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43l+\r\nastpwuh73k29qs+\r  y",
1416                         // Two blinded paths
1417                         "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",
1418                 ];
1419                 for encoded_offer in &offers {
1420                         if let Err(e) = encoded_offer.parse::<Offer>() {
1421                                 panic!("Invalid offer ({:?}): {}", e, encoded_offer);
1422                         }
1423                 }
1424         }
1425
1426         #[test]
1427         fn fails_parsing_bech32_encoded_offers_with_invalid_continuations() {
1428                 let offers = [
1429                         // BOLT 12 test vectors
1430                         "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy+",
1431                         "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy+ ",
1432                         "+lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1433                         "+ lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1434                         "ln++o1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy",
1435                 ];
1436                 for encoded_offer in &offers {
1437                         match encoded_offer.parse::<Offer>() {
1438                                 Ok(_) => panic!("Valid offer: {}", encoded_offer),
1439                                 Err(e) => assert_eq!(e, ParseError::InvalidContinuation),
1440                         }
1441                 }
1442
1443         }
1444
1445         #[test]
1446         fn fails_parsing_bech32_encoded_offer_with_invalid_hrp() {
1447                 let encoded_offer = "lni1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsy";
1448                 match encoded_offer.parse::<Offer>() {
1449                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1450                         Err(e) => assert_eq!(e, ParseError::InvalidBech32Hrp),
1451                 }
1452         }
1453
1454         #[test]
1455         fn fails_parsing_bech32_encoded_offer_with_invalid_bech32_data() {
1456                 let encoded_offer = "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qso";
1457                 match encoded_offer.parse::<Offer>() {
1458                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1459                         Err(e) => assert_eq!(e, ParseError::Bech32(bech32::Error::InvalidChar('o'))),
1460                 }
1461         }
1462
1463         #[test]
1464         fn fails_parsing_bech32_encoded_offer_with_invalid_tlv_data() {
1465                 let encoded_offer = "lno1qcp4256ypqpq86q2pucnq42ngssx2an9wfujqerp0y2pqun4wd68jtn00fkxzcnn9ehhyec6qgqsz83qfwdpl28qqmc78ymlvhmxcsywdk5wrjnj36jryg488qwlrnzyjczlqsp9nyu4phcg6dqhlhzgxagfu7zh3d9re0sqp9ts2yfugvnnm9gxkcnnnkdpa084a6t520h5zhkxsdnghvpukvd43lastpwuh73k29qsyqqqqq";
1466                 match encoded_offer.parse::<Offer>() {
1467                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1468                         Err(e) => assert_eq!(e, ParseError::Decode(DecodeError::InvalidValue)),
1469                 }
1470         }
1471 }