git.bitcoin.ninja Git - rust-lightning/blob - lightning/src/offers/offer.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! Data structures and encoding for `offer` messages.
  11 //!
  12 //! An [`Offer`] represents an "offer to be paid." It is typically constructed by a merchant and
  13 //! published as a QR code to be scanned by a customer. The customer uses the offer to request an
  14 //! invoice from the merchant to be paid.
  15 //!
  16 //! ```
  17 //! extern crate bitcoin;
  18 //! extern crate core;
  19 //! extern crate lightning;
  20 //!
  21 //! use core::convert::TryFrom;
  22 //! use core::num::NonZeroU64;
  23 //! use core::time::Duration;
  24 //!
  25 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
  26 //! use lightning::offers::offer::{Offer, OfferBuilder, Quantity};
  27 //! use lightning::offers::parse::Bolt12ParseError;
  28 //! use lightning::util::ser::{Readable, Writeable};
  29 //!
  30 //! # use lightning::blinded_path::BlindedPath;
  31 //! # #[cfg(feature = "std")]
  32 //! # use std::time::SystemTime;
  33 //! #
  34 //! # fn create_blinded_path() -> BlindedPath { unimplemented!() }
  35 //! # fn create_another_blinded_path() -> BlindedPath { unimplemented!() }
  36 //! #
  37 //! # #[cfg(feature = "std")]
  38 //! # fn build() -> Result<(), Bolt12ParseError> {
  39 //! let secp_ctx = Secp256k1::new();
  40 //! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
  41 //! let pubkey = PublicKey::from(keys);
  42 //!
  43 //! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
  44 //! let offer = OfferBuilder::new("coffee, large".to_string(), pubkey)
  45 //!     .amount_msats(20_000)
  46 //!     .supported_quantity(Quantity::Unbounded)
  47 //!     .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
  48 //!     .issuer("Foo Bar".to_string())
  49 //!     .path(create_blinded_path())
  50 //!     .path(create_another_blinded_path())
  51 //!     .build()?;
  52 //!
  53 //! // Encode as a bech32 string for use in a QR code.
  54 //! let encoded_offer = offer.to_string();
  55 //!
  56 //! // Parse from a bech32 string after scanning from a QR code.
  57 //! let offer = encoded_offer.parse::<Offer>()?;
  58 //!
  59 //! // Encode offer as raw bytes.
  60 //! let mut bytes = Vec::new();
  61 //! offer.write(&mut bytes).unwrap();
  62 //!
  63 //! // Decode raw bytes into an offer.
  64 //! let offer = Offer::try_from(bytes)?;
  65 //! # Ok(())
  66 //! # }
  67 //! ```
  68
  69 use bitcoin::blockdata::constants::ChainHash;
  70 use bitcoin::network::constants::Network;
  71 use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, self};
  72 use core::convert::TryFrom;
  73 use core::num::NonZeroU64;
  74 use core::ops::Deref;
  75 use core::str::FromStr;
  76 use core::time::Duration;
  77 use crate::sign::EntropySource;
  78 use crate::io;
  79 use crate::blinded_path::BlindedPath;
  80 use crate::ln::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, Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
  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 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 102 ///
 103 /// [module-level documentation]: self
 104 pub struct OfferBuilder<'a, M: MetadataStrategy, T: secp256k1::Signing> {
 105         offer: OfferContents,
 106         metadata_strategy: core::marker::PhantomData<M>,
 107         secp_ctx: Option<&'a Secp256k1<T>>,
 108 }
 109
 110 /// Indicates how [`Offer::metadata`] may be set.
 111 ///
 112 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 113 pub trait MetadataStrategy {}
 114
 115 /// [`Offer::metadata`] may be explicitly set or left empty.
 116 ///
 117 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 118 pub struct ExplicitMetadata {}
 119
 120 /// [`Offer::metadata`] will be derived.
 121 ///
 122 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 123 pub struct DerivedMetadata {}
 124
 125 impl MetadataStrategy for ExplicitMetadata {}
 126 impl MetadataStrategy for DerivedMetadata {}
 127
 128 impl<'a> OfferBuilder<'a, ExplicitMetadata, secp256k1::SignOnly> {
 129         /// Creates a new builder for an offer setting the [`Offer::description`] and using the
 130         /// [`Offer::signing_pubkey`] for signing invoices. The associated secret key must be remembered
 131         /// while the offer is valid.
 132         ///
 133         /// Use a different pubkey per offer to avoid correlating offers.
 134         pub fn new(description: String, signing_pubkey: PublicKey) -> Self {
 135                 OfferBuilder {
 136                         offer: OfferContents {
 137                                 chains: None, metadata: None, amount: None, description,
 138                                 features: OfferFeatures::empty(), absolute_expiry: None, issuer: None, paths: None,
 139                                 supported_quantity: Quantity::One, signing_pubkey,
 140                         },
 141                         metadata_strategy: core::marker::PhantomData,
 142                         secp_ctx: None,
 143                 }
 144         }
 145
 146         /// Sets the [`Offer::metadata`] to the given bytes.
 147         ///
 148         /// Successive calls to this method will override the previous setting.
 149         pub fn metadata(mut self, metadata: Vec<u8>) -> Result<Self, Bolt12SemanticError> {
 150                 self.offer.metadata = Some(Metadata::Bytes(metadata));
 151                 Ok(self)
 152         }
 153 }
 154
 155 impl<'a, T: secp256k1::Signing> OfferBuilder<'a, DerivedMetadata, T> {
 156         /// Similar to [`OfferBuilder::new`] except, if [`OfferBuilder::path`] is called, the signing
 157         /// pubkey is derived from the given [`ExpandedKey`] and [`EntropySource`]. This provides
 158         /// recipient privacy by using a different signing pubkey for each offer. Otherwise, the
 159         /// provided `node_id` is used for the signing pubkey.
 160         ///
 161         /// Also, sets the metadata when [`OfferBuilder::build`] is called such that it can be used by
 162         /// [`InvoiceRequest::verify`] to determine if the request was produced for the offer given an
 163         /// [`ExpandedKey`].
 164         ///
 165         /// [`InvoiceRequest::verify`]: crate::offers::invoice_request::InvoiceRequest::verify
 166         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 167         pub fn deriving_signing_pubkey<ES: Deref>(
 168                 description: String, node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 169                 secp_ctx: &'a Secp256k1<T>
 170         ) -> Self where ES::Target: EntropySource {
 171                 let nonce = Nonce::from_entropy_source(entropy_source);
 172                 let derivation_material = MetadataMaterial::new(nonce, expanded_key, IV_BYTES);
 173                 let metadata = Metadata::DerivedSigningPubkey(derivation_material);
 174                 OfferBuilder {
 175                         offer: OfferContents {
 176                                 chains: None, metadata: Some(metadata), amount: None, description,
 177                                 features: OfferFeatures::empty(), absolute_expiry: None, issuer: None, paths: None,
 178                                 supported_quantity: Quantity::One, signing_pubkey: node_id,
 179                         },
 180                         metadata_strategy: core::marker::PhantomData,
 181                         secp_ctx: Some(secp_ctx),
 182                 }
 183         }
 184 }
 185
 186 impl<'a, M: MetadataStrategy, T: secp256k1::Signing> OfferBuilder<'a, M, T> {
 187         /// Adds the chain hash of the given [`Network`] to [`Offer::chains`]. If not called,
 188         /// the chain hash of [`Network::Bitcoin`] is assumed to be the only one supported.
 189         ///
 190         /// See [`Offer::chains`] on how this relates to the payment currency.
 191         ///
 192         /// Successive calls to this method will add another chain hash.
 193         pub fn chain(mut self, network: Network) -> Self {
 194                 let chains = self.offer.chains.get_or_insert_with(Vec::new);
 195                 let chain = ChainHash::using_genesis_block(network);
 196                 if !chains.contains(&chain) {
 197                         chains.push(chain);
 198                 }
 199
 200                 self
 201         }
 202
 203         /// Sets the [`Offer::amount`] as an [`Amount::Bitcoin`].
 204         ///
 205         /// Successive calls to this method will override the previous setting.
 206         pub fn amount_msats(self, amount_msats: u64) -> Self {
 207                 self.amount(Amount::Bitcoin { amount_msats })
 208         }
 209
 210         /// Sets the [`Offer::amount`].
 211         ///
 212         /// Successive calls to this method will override the previous setting.
 213         pub(super) fn amount(mut self, amount: Amount) -> Self {
 214                 self.offer.amount = Some(amount);
 215                 self
 216         }
 217
 218         /// Sets the [`Offer::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
 219         /// already passed is valid and can be checked for using [`Offer::is_expired`].
 220         ///
 221         /// Successive calls to this method will override the previous setting.
 222         pub fn absolute_expiry(mut self, absolute_expiry: Duration) -> Self {
 223                 self.offer.absolute_expiry = Some(absolute_expiry);
 224                 self
 225         }
 226
 227         /// Sets the [`Offer::issuer`].
 228         ///
 229         /// Successive calls to this method will override the previous setting.
 230         pub fn issuer(mut self, issuer: String) -> Self {
 231                 self.offer.issuer = Some(issuer);
 232                 self
 233         }
 234
 235         /// Adds a blinded path to [`Offer::paths`]. Must include at least one path if only connected by
 236         /// private channels or if [`Offer::signing_pubkey`] is not a public node id.
 237         ///
 238         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 239         /// adding duplicate paths.
 240         pub fn path(mut self, path: BlindedPath) -> Self {
 241                 self.offer.paths.get_or_insert_with(Vec::new).push(path);
 242                 self
 243         }
 244
 245         /// Sets the quantity of items for [`Offer::supported_quantity`]. If not called, defaults to
 246         /// [`Quantity::One`].
 247         ///
 248         /// Successive calls to this method will override the previous setting.
 249         pub fn supported_quantity(mut self, quantity: Quantity) -> Self {
 250                 self.offer.supported_quantity = quantity;
 251                 self
 252         }
 253
 254         /// Builds an [`Offer`] from the builder's settings.
 255         pub fn build(mut self) -> Result<Offer, Bolt12SemanticError> {
 256                 match self.offer.amount {
 257                         Some(Amount::Bitcoin { amount_msats }) => {
 258                                 if amount_msats > MAX_VALUE_MSAT {
 259                                         return Err(Bolt12SemanticError::InvalidAmount);
 260                                 }
 261                         },
 262                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 263                         None => {},
 264                 }
 265
 266                 if let Some(chains) = &self.offer.chains {
 267                         if chains.len() == 1 && chains[0] == self.offer.implied_chain() {
 268                                 self.offer.chains = None;
 269                         }
 270                 }
 271
 272                 Ok(self.build_without_checks())
 273         }
 274
 275         fn build_without_checks(mut self) -> Offer {
 276                 // Create the metadata for stateless verification of an InvoiceRequest.
 277                 if let Some(mut metadata) = self.offer.metadata.take() {
 278                         if metadata.has_derivation_material() {
 279                                 if self.offer.paths.is_none() {
 280                                         metadata = metadata.without_keys();
 281                                 }
 282
 283                                 let mut tlv_stream = self.offer.as_tlv_stream();
 284                                 debug_assert_eq!(tlv_stream.metadata, None);
 285                                 tlv_stream.metadata = None;
 286                                 if metadata.derives_keys() {
 287                                         tlv_stream.node_id = None;
 288                                 }
 289
 290                                 let (derived_metadata, keys) = metadata.derive_from(tlv_stream, self.secp_ctx);
 291                                 metadata = derived_metadata;
 292                                 if let Some(keys) = keys {
 293                                         self.offer.signing_pubkey = keys.public_key();
 294                                 }
 295                         }
 296
 297                         self.offer.metadata = Some(metadata);
 298                 }
 299
 300                 let mut bytes = Vec::new();
 301                 self.offer.write(&mut bytes).unwrap();
 302
 303                 Offer { bytes, contents: self.offer }
 304         }
 305 }
 306
 307 #[cfg(test)]
 308 impl<'a, M: MetadataStrategy, T: secp256k1::Signing> OfferBuilder<'a, M, T> {
 309         fn features_unchecked(mut self, features: OfferFeatures) -> Self {
 310                 self.offer.features = features;
 311                 self
 312         }
 313
 314         pub(super) fn build_unchecked(self) -> Offer {
 315                 self.build_without_checks()
 316         }
 317 }
 318
 319 /// An `Offer` is a potentially long-lived proposal for payment of a good or service.
 320 ///
 321 /// An offer is a precursor to an [`InvoiceRequest`]. A merchant publishes an offer from which a
 322 /// customer may request an [`Bolt12Invoice`] for a specific quantity and using an amount sufficient
 323 /// to cover that quantity (i.e., at least `quantity * amount`). See [`Offer::amount`].
 324 ///
 325 /// Offers may be denominated in currency other than bitcoin but are ultimately paid using the
 326 /// latter.
 327 ///
 328 /// Through the use of [`BlindedPath`]s, offers provide recipient privacy.
 329 ///
 330 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 331 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 332 #[derive(Clone, Debug)]
 333 #[cfg_attr(test, derive(PartialEq))]
 334 pub struct Offer {
 335         // The serialized offer. Needed when creating an `InvoiceRequest` if the offer contains unknown
 336         // fields.
 337         pub(super) bytes: Vec<u8>,
 338         pub(super) contents: OfferContents,
 339 }
 340
 341 /// The contents of an [`Offer`], which may be shared with an [`InvoiceRequest`] or a
 342 /// [`Bolt12Invoice`].
 343 ///
 344 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 345 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 346 #[derive(Clone, Debug)]
 347 #[cfg_attr(test, derive(PartialEq))]
 348 pub(super) struct OfferContents {
 349         chains: Option<Vec<ChainHash>>,
 350         metadata: Option<Metadata>,
 351         amount: Option<Amount>,
 352         description: String,
 353         features: OfferFeatures,
 354         absolute_expiry: Option<Duration>,
 355         issuer: Option<String>,
 356         paths: Option<Vec<BlindedPath>>,
 357         supported_quantity: Quantity,
 358         signing_pubkey: PublicKey,
 359 }
 360
 361 macro_rules! offer_accessors { ($self: ident, $contents: expr) => {
 362         // TODO: Return a slice once ChainHash has constants.
 363         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1283
 364         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1286
 365         /// The chains that may be used when paying a requested invoice (e.g., bitcoin mainnet).
 366         /// Payments must be denominated in units of the minimal lightning-payable unit (e.g., msats)
 367         /// for the selected chain.
 368         pub fn chains(&$self) -> Vec<$crate::bitcoin::blockdata::constants::ChainHash> {
 369                 $contents.chains()
 370         }
 371
 372         // TODO: Link to corresponding method in `InvoiceRequest`.
 373         /// Opaque bytes set by the originator. Useful for authentication and validating fields since it
 374         /// is reflected in `invoice_request` messages along with all the other fields from the `offer`.
 375         pub fn metadata(&$self) -> Option<&Vec<u8>> {
 376                 $contents.metadata()
 377         }
 378
 379         /// The minimum amount required for a successful payment of a single item.
 380         pub fn amount(&$self) -> Option<&$crate::offers::offer::Amount> {
 381                 $contents.amount()
 382         }
 383
 384         /// A complete description of the purpose of the payment. Intended to be displayed to the user
 385         /// but with the caveat that it has not been verified in any way.
 386         pub fn description(&$self) -> $crate::util::string::PrintableString {
 387                 $contents.description()
 388         }
 389
 390         /// Features pertaining to the offer.
 391         pub fn offer_features(&$self) -> &$crate::ln::features::OfferFeatures {
 392                 &$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<core::time::Duration> {
 399                 $contents.absolute_expiry()
 400         }
 401
 402         /// The issuer of the offer, possibly beginning with `user@domain` or `domain`. Intended to be
 403         /// displayed to the user but with the caveat that it has not been verified in any way.
 404         pub fn issuer(&$self) -> Option<$crate::util::string::PrintableString> {
 405                 $contents.issuer()
 406         }
 407
 408         /// Paths to the recipient originating from publicly reachable nodes. Blinded paths provide
 409         /// recipient privacy by obfuscating its node id.
 410         pub fn paths(&$self) -> &[$crate::blinded_path::BlindedPath] {
 411                 $contents.paths()
 412         }
 413
 414         /// The quantity of items supported.
 415         pub fn supported_quantity(&$self) -> $crate::offers::offer::Quantity {
 416                 $contents.supported_quantity()
 417         }
 418
 419         /// The public key used by the recipient to sign invoices.
 420         pub fn signing_pubkey(&$self) -> $crate::bitcoin::secp256k1::PublicKey {
 421                 $contents.signing_pubkey()
 422         }
 423 } }
 424
 425 impl Offer {
 426         offer_accessors!(self, self.contents);
 427
 428         pub(super) fn implied_chain(&self) -> ChainHash {
 429                 self.contents.implied_chain()
 430         }
 431
 432         /// Returns whether the given chain is supported by the offer.
 433         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 434                 self.contents.supports_chain(chain)
 435         }
 436
 437         /// Whether the offer has expired.
 438         #[cfg(feature = "std")]
 439         pub fn is_expired(&self) -> bool {
 440                 self.contents.is_expired()
 441         }
 442
 443         /// Returns whether the given quantity is valid for the offer.
 444         pub fn is_valid_quantity(&self, quantity: u64) -> bool {
 445                 self.contents.is_valid_quantity(quantity)
 446         }
 447
 448         /// Returns whether a quantity is expected in an [`InvoiceRequest`] for the offer.
 449         ///
 450         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 451         pub fn expects_quantity(&self) -> bool {
 452                 self.contents.expects_quantity()
 453         }
 454
 455         /// Similar to [`Offer::request_invoice`] except it:
 456         /// - derives the [`InvoiceRequest::payer_id`] such that a different key can be used for each
 457         ///   request, and
 458         /// - sets the [`InvoiceRequest::payer_metadata`] when [`InvoiceRequestBuilder::build`] is
 459         ///   called such that it can be used by [`Bolt12Invoice::verify`] to determine if the invoice
 460         ///   was requested using a base [`ExpandedKey`] from which the payer id was derived.
 461         ///
 462         /// Useful to protect the sender's privacy.
 463         ///
 464         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 465         ///
 466         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 467         /// [`InvoiceRequest::payer_metadata`]: crate::offers::invoice_request::InvoiceRequest::payer_metadata
 468         /// [`Bolt12Invoice::verify`]: crate::offers::invoice::Bolt12Invoice::verify
 469         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 470         pub fn request_invoice_deriving_payer_id<'a, 'b, ES: Deref, T: secp256k1::Signing>(
 471                 &'a self, expanded_key: &ExpandedKey, entropy_source: ES, secp_ctx: &'b Secp256k1<T>
 472         ) -> Result<InvoiceRequestBuilder<'a, 'b, DerivedPayerId, T>, Bolt12SemanticError>
 473         where
 474                 ES::Target: EntropySource,
 475         {
 476                 if self.offer_features().requires_unknown_bits() {
 477                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 478                 }
 479
 480                 Ok(InvoiceRequestBuilder::deriving_payer_id(self, expanded_key, entropy_source, secp_ctx))
 481         }
 482
 483         /// Similar to [`Offer::request_invoice_deriving_payer_id`] except uses `payer_id` for the
 484         /// [`InvoiceRequest::payer_id`] instead of deriving a different key for each request.
 485         ///
 486         /// Useful for recurring payments using the same `payer_id` with different invoices.
 487         ///
 488         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 489         ///
 490         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 491         pub fn request_invoice_deriving_metadata<ES: Deref>(
 492                 &self, payer_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES
 493         ) -> Result<InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>, Bolt12SemanticError>
 494         where
 495                 ES::Target: EntropySource,
 496         {
 497                 if self.offer_features().requires_unknown_bits() {
 498                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 499                 }
 500
 501                 Ok(InvoiceRequestBuilder::deriving_metadata(self, payer_id, expanded_key, entropy_source))
 502         }
 503
 504         /// Creates an [`InvoiceRequestBuilder`] for the offer with the given `metadata` and `payer_id`,
 505         /// which will be reflected in the `Bolt12Invoice` response.
 506         ///
 507         /// The `metadata` is useful for including information about the derivation of `payer_id` such
 508         /// that invoice response handling can be stateless. Also serves as payer-provided entropy while
 509         /// hashing in the signature calculation.
 510         ///
 511         /// This should not leak any information such as by using a simple BIP-32 derivation path.
 512         /// Otherwise, payments may be correlated.
 513         ///
 514         /// Errors if the offer contains unknown required features.
 515         ///
 516         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 517         ///
 518         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 519         pub fn request_invoice(
 520                 &self, metadata: Vec<u8>, payer_id: PublicKey
 521         ) -> Result<InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>, Bolt12SemanticError> {
 522                 if self.offer_features().requires_unknown_bits() {
 523                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 524                 }
 525
 526                 Ok(InvoiceRequestBuilder::new(self, metadata, payer_id))
 527         }
 528
 529         #[cfg(test)]
 530         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 531                 self.contents.as_tlv_stream()
 532         }
 533 }
 534
 535 impl AsRef<[u8]> for Offer {
 536         fn as_ref(&self) -> &[u8] {
 537                 &self.bytes
 538         }
 539 }
 540
 541 impl OfferContents {
 542         pub fn chains(&self) -> Vec<ChainHash> {
 543                 self.chains.as_ref().cloned().unwrap_or_else(|| vec![self.implied_chain()])
 544         }
 545
 546         pub fn implied_chain(&self) -> ChainHash {
 547                 ChainHash::using_genesis_block(Network::Bitcoin)
 548         }
 549
 550         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 551                 self.chains().contains(&chain)
 552         }
 553
 554         pub fn metadata(&self) -> Option<&Vec<u8>> {
 555                 self.metadata.as_ref().and_then(|metadata| metadata.as_bytes())
 556         }
 557
 558         pub fn amount(&self) -> Option<&Amount> {
 559                 self.amount.as_ref()
 560         }
 561
 562         pub fn description(&self) -> PrintableString {
 563                 PrintableString(&self.description)
 564         }
 565
 566         pub fn features(&self) -> &OfferFeatures {
 567                 &self.features
 568         }
 569
 570         pub fn absolute_expiry(&self) -> Option<Duration> {
 571                 self.absolute_expiry
 572         }
 573
 574         #[cfg(feature = "std")]
 575         pub(super) fn is_expired(&self) -> bool {
 576                 match self.absolute_expiry {
 577                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
 578                                 Ok(elapsed) => elapsed > seconds_from_epoch,
 579                                 Err(_) => false,
 580                         },
 581                         None => false,
 582                 }
 583         }
 584
 585         pub fn issuer(&self) -> Option<PrintableString> {
 586                 self.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 587         }
 588
 589         pub fn paths(&self) -> &[BlindedPath] {
 590                 self.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 591         }
 592
 593         pub(super) fn check_amount_msats_for_quantity(
 594                 &self, amount_msats: Option<u64>, quantity: Option<u64>
 595         ) -> Result<(), Bolt12SemanticError> {
 596                 let offer_amount_msats = match self.amount {
 597                         None => 0,
 598                         Some(Amount::Bitcoin { amount_msats }) => amount_msats,
 599                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 600                 };
 601
 602                 if !self.expects_quantity() || quantity.is_some() {
 603                         let expected_amount_msats = offer_amount_msats.checked_mul(quantity.unwrap_or(1))
 604                                 .ok_or(Bolt12SemanticError::InvalidAmount)?;
 605                         let amount_msats = amount_msats.unwrap_or(expected_amount_msats);
 606
 607                         if amount_msats < expected_amount_msats {
 608                                 return Err(Bolt12SemanticError::InsufficientAmount);
 609                         }
 610
 611                         if amount_msats > MAX_VALUE_MSAT {
 612                                 return Err(Bolt12SemanticError::InvalidAmount);
 613                         }
 614                 }
 615
 616                 Ok(())
 617         }
 618
 619         pub fn supported_quantity(&self) -> Quantity {
 620                 self.supported_quantity
 621         }
 622
 623         pub(super) fn check_quantity(&self, quantity: Option<u64>) -> Result<(), Bolt12SemanticError> {
 624                 let expects_quantity = self.expects_quantity();
 625                 match quantity {
 626                         None if expects_quantity => Err(Bolt12SemanticError::MissingQuantity),
 627                         Some(_) if !expects_quantity => Err(Bolt12SemanticError::UnexpectedQuantity),
 628                         Some(quantity) if !self.is_valid_quantity(quantity) => {
 629                                 Err(Bolt12SemanticError::InvalidQuantity)
 630                         },
 631                         _ => Ok(()),
 632                 }
 633         }
 634
 635         fn is_valid_quantity(&self, quantity: u64) -> bool {
 636                 match self.supported_quantity {
 637                         Quantity::Bounded(n) => quantity <= n.get(),
 638                         Quantity::Unbounded => quantity > 0,
 639                         Quantity::One => quantity == 1,
 640                 }
 641         }
 642
 643         fn expects_quantity(&self) -> bool {
 644                 match self.supported_quantity {
 645                         Quantity::Bounded(_) => true,
 646                         Quantity::Unbounded => true,
 647                         Quantity::One => false,
 648                 }
 649         }
 650
 651         pub(super) fn signing_pubkey(&self) -> PublicKey {
 652                 self.signing_pubkey
 653         }
 654
 655         /// Verifies that the offer metadata was produced from the offer in the TLV stream.
 656         pub(super) fn verify<T: secp256k1::Signing>(
 657                 &self, bytes: &[u8], key: &ExpandedKey, secp_ctx: &Secp256k1<T>
 658         ) -> Result<Option<KeyPair>, ()> {
 659                 match self.metadata() {
 660                         Some(metadata) => {
 661                                 let tlv_stream = TlvStream::new(bytes).range(OFFER_TYPES).filter(|record| {
 662                                         match record.r#type {
 663                                                 OFFER_METADATA_TYPE => false,
 664                                                 OFFER_NODE_ID_TYPE => !self.metadata.as_ref().unwrap().derives_keys(),
 665                                                 _ => true,
 666                                         }
 667                                 });
 668                                 signer::verify_metadata(
 669                                         metadata, key, IV_BYTES, self.signing_pubkey(), tlv_stream, secp_ctx
 670                                 )
 671                         },
 672                         None => Err(()),
 673                 }
 674         }
 675
 676         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 677                 let (currency, amount) = match &self.amount {
 678                         None => (None, None),
 679                         Some(Amount::Bitcoin { amount_msats }) => (None, Some(*amount_msats)),
 680                         Some(Amount::Currency { iso4217_code, amount }) => (
 681                                 Some(iso4217_code), Some(*amount)
 682                         ),
 683                 };
 684
 685                 let features = {
 686                         if self.features == OfferFeatures::empty() { None } else { Some(&self.features) }
 687                 };
 688
 689                 OfferTlvStreamRef {
 690                         chains: self.chains.as_ref(),
 691                         metadata: self.metadata(),
 692                         currency,
 693                         amount,
 694                         description: Some(&self.description),
 695                         features,
 696                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 697                         paths: self.paths.as_ref(),
 698                         issuer: self.issuer.as_ref(),
 699                         quantity_max: self.supported_quantity.to_tlv_record(),
 700                         node_id: Some(&self.signing_pubkey),
 701                 }
 702         }
 703 }
 704
 705 impl Writeable for Offer {
 706         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 707                 WithoutLength(&self.bytes).write(writer)
 708         }
 709 }
 710
 711 impl Writeable for OfferContents {
 712         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 713                 self.as_tlv_stream().write(writer)
 714         }
 715 }
 716
 717 /// The minimum amount required for an item in an [`Offer`], denominated in either bitcoin or
 718 /// another currency.
 719 #[derive(Clone, Debug, PartialEq)]
 720 pub enum Amount {
 721         /// An amount of bitcoin.
 722         Bitcoin {
 723                 /// The amount in millisatoshi.
 724                 amount_msats: u64,
 725         },
 726         /// An amount of currency specified using ISO 4712.
 727         Currency {
 728                 /// The currency that the amount is denominated in.
 729                 iso4217_code: CurrencyCode,
 730                 /// The amount in the currency unit adjusted by the ISO 4712 exponent (e.g., USD cents).
 731                 amount: u64,
 732         },
 733 }
 734
 735 /// An ISO 4712 three-letter currency code (e.g., USD).
 736 pub type CurrencyCode = [u8; 3];
 737
 738 /// Quantity of items supported by an [`Offer`].
 739 #[derive(Clone, Copy, Debug, PartialEq)]
 740 pub enum Quantity {
 741         /// Up to a specific number of items (inclusive). Use when more than one item can be requested
 742         /// but is limited (e.g., because of per customer or inventory limits).
 743         ///
 744         /// May be used with `NonZeroU64::new(1)` but prefer to use [`Quantity::One`] if only one item
 745         /// is supported.
 746         Bounded(NonZeroU64),
 747         /// One or more items. Use when more than one item can be requested without any limit.
 748         Unbounded,
 749         /// Only one item. Use when only a single item can be requested.
 750         One,
 751 }
 752
 753 impl Quantity {
 754         fn to_tlv_record(&self) -> Option<u64> {
 755                 match self {
 756                         Quantity::Bounded(n) => Some(n.get()),
 757                         Quantity::Unbounded => Some(0),
 758                         Quantity::One => None,
 759                 }
 760         }
 761 }
 762
 763 /// Valid type range for offer TLV records.
 764 pub(super) const OFFER_TYPES: core::ops::Range<u64> = 1..80;
 765
 766 /// TLV record type for [`Offer::metadata`].
 767 const OFFER_METADATA_TYPE: u64 = 4;
 768
 769 /// TLV record type for [`Offer::signing_pubkey`].
 770 const OFFER_NODE_ID_TYPE: u64 = 22;
 771
 772 tlv_stream!(OfferTlvStream, OfferTlvStreamRef, OFFER_TYPES, {
 773         (2, chains: (Vec<ChainHash>, WithoutLength)),
 774         (OFFER_METADATA_TYPE, metadata: (Vec<u8>, WithoutLength)),
 775         (6, currency: CurrencyCode),
 776         (8, amount: (u64, HighZeroBytesDroppedBigSize)),
 777         (10, description: (String, WithoutLength)),
 778         (12, features: (OfferFeatures, WithoutLength)),
 779         (14, absolute_expiry: (u64, HighZeroBytesDroppedBigSize)),
 780         (16, paths: (Vec<BlindedPath>, WithoutLength)),
 781         (18, issuer: (String, WithoutLength)),
 782         (20, quantity_max: (u64, HighZeroBytesDroppedBigSize)),
 783         (OFFER_NODE_ID_TYPE, node_id: PublicKey),
 784 });
 785
 786 impl Bech32Encode for Offer {
 787         const BECH32_HRP: &'static str = "lno";
 788 }
 789
 790 impl FromStr for Offer {
 791         type Err = Bolt12ParseError;
 792
 793         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 794                 Self::from_bech32_str(s)
 795         }
 796 }
 797
 798 impl TryFrom<Vec<u8>> for Offer {
 799         type Error = Bolt12ParseError;
 800
 801         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 802                 let offer = ParsedMessage::<OfferTlvStream>::try_from(bytes)?;
 803                 let ParsedMessage { bytes, tlv_stream } = offer;
 804                 let contents = OfferContents::try_from(tlv_stream)?;
 805                 Ok(Offer { bytes, contents })
 806         }
 807 }
 808
 809 impl TryFrom<OfferTlvStream> for OfferContents {
 810         type Error = Bolt12SemanticError;
 811
 812         fn try_from(tlv_stream: OfferTlvStream) -> Result<Self, Self::Error> {
 813                 let OfferTlvStream {
 814                         chains, metadata, currency, amount, description, features, absolute_expiry, paths,
 815                         issuer, quantity_max, node_id,
 816                 } = tlv_stream;
 817
 818                 let metadata = metadata.map(|metadata| Metadata::Bytes(metadata));
 819
 820                 let amount = match (currency, amount) {
 821                         (None, None) => None,
 822                         (None, Some(amount_msats)) if amount_msats > MAX_VALUE_MSAT => {
 823                                 return Err(Bolt12SemanticError::InvalidAmount);
 824                         },
 825                         (None, Some(amount_msats)) => Some(Amount::Bitcoin { amount_msats }),
 826                         (Some(_), None) => return Err(Bolt12SemanticError::MissingAmount),
 827                         (Some(iso4217_code), Some(amount)) => Some(Amount::Currency { iso4217_code, amount }),
 828                 };
 829
 830                 let description = match description {
 831                         None => return Err(Bolt12SemanticError::MissingDescription),
 832                         Some(description) => description,
 833                 };
 834
 835                 let features = features.unwrap_or_else(OfferFeatures::empty);
 836
 837                 let absolute_expiry = absolute_expiry
 838                         .map(|seconds_from_epoch| Duration::from_secs(seconds_from_epoch));
 839
 840                 let supported_quantity = match quantity_max {
 841                         None => Quantity::One,
 842                         Some(0) => Quantity::Unbounded,
 843                         Some(n) => Quantity::Bounded(NonZeroU64::new(n).unwrap()),
 844                 };
 845
 846                 let signing_pubkey = match node_id {
 847                         None => return Err(Bolt12SemanticError::MissingSigningPubkey),
 848                         Some(node_id) => node_id,
 849                 };
 850
 851                 Ok(OfferContents {
 852                         chains, metadata, amount, description, features, absolute_expiry, issuer, paths,
 853                         supported_quantity, signing_pubkey,
 854                 })
 855         }
 856 }
 857
 858 impl core::fmt::Display for Offer {
 859         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 860                 self.fmt_bech32_str(f)
 861         }
 862 }
 863
 864 #[cfg(test)]
 865 mod tests {
 866         use super::{Amount, Offer, OfferBuilder, OfferTlvStreamRef, Quantity};
 867
 868         use bitcoin::blockdata::constants::ChainHash;
 869         use bitcoin::network::constants::Network;
 870         use bitcoin::secp256k1::Secp256k1;
 871         use core::convert::TryFrom;
 872         use core::num::NonZeroU64;
 873         use core::time::Duration;
 874         use crate::blinded_path::{BlindedHop, BlindedPath};
 875         use crate::sign::KeyMaterial;
 876         use crate::ln::features::OfferFeatures;
 877         use crate::ln::inbound_payment::ExpandedKey;
 878         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 879         use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
 880         use crate::offers::test_utils::*;
 881         use crate::util::ser::{BigSize, Writeable};
 882         use crate::util::string::PrintableString;
 883
 884         #[test]
 885         fn builds_offer_with_defaults() {
 886                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
 887
 888                 let mut buffer = Vec::new();
 889                 offer.write(&mut buffer).unwrap();
 890
 891                 assert_eq!(offer.bytes, buffer.as_slice());
 892                 assert_eq!(offer.chains(), vec![ChainHash::using_genesis_block(Network::Bitcoin)]);
 893                 assert!(offer.supports_chain(ChainHash::using_genesis_block(Network::Bitcoin)));
 894                 assert_eq!(offer.metadata(), None);
 895                 assert_eq!(offer.amount(), None);
 896                 assert_eq!(offer.description(), PrintableString("foo"));
 897                 assert_eq!(offer.offer_features(), &OfferFeatures::empty());
 898                 assert_eq!(offer.absolute_expiry(), None);
 899                 #[cfg(feature = "std")]
 900                 assert!(!offer.is_expired());
 901                 assert_eq!(offer.paths(), &[]);
 902                 assert_eq!(offer.issuer(), None);
 903                 assert_eq!(offer.supported_quantity(), Quantity::One);
 904                 assert_eq!(offer.signing_pubkey(), pubkey(42));
 905
 906                 assert_eq!(
 907                         offer.as_tlv_stream(),
 908                         OfferTlvStreamRef {
 909                                 chains: None,
 910                                 metadata: None,
 911                                 currency: None,
 912                                 amount: None,
 913                                 description: Some(&String::from("foo")),
 914                                 features: None,
 915                                 absolute_expiry: None,
 916                                 paths: None,
 917                                 issuer: None,
 918                                 quantity_max: None,
 919                                 node_id: Some(&pubkey(42)),
 920                         },
 921                 );
 922
 923                 if let Err(e) = Offer::try_from(buffer) {
 924                         panic!("error parsing offer: {:?}", e);
 925                 }
 926         }
 927
 928         #[test]
 929         fn builds_offer_with_chains() {
 930                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
 931                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
 932
 933                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 934                         .chain(Network::Bitcoin)
 935                         .build()
 936                         .unwrap();
 937                 assert!(offer.supports_chain(mainnet));
 938                 assert_eq!(offer.chains(), vec![mainnet]);
 939                 assert_eq!(offer.as_tlv_stream().chains, None);
 940
 941                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 942                         .chain(Network::Testnet)
 943                         .build()
 944                         .unwrap();
 945                 assert!(offer.supports_chain(testnet));
 946                 assert_eq!(offer.chains(), vec![testnet]);
 947                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 948
 949                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 950                         .chain(Network::Testnet)
 951                         .chain(Network::Testnet)
 952                         .build()
 953                         .unwrap();
 954                 assert!(offer.supports_chain(testnet));
 955                 assert_eq!(offer.chains(), vec![testnet]);
 956                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 957
 958                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 959                         .chain(Network::Bitcoin)
 960                         .chain(Network::Testnet)
 961                         .build()
 962                         .unwrap();
 963                 assert!(offer.supports_chain(mainnet));
 964                 assert!(offer.supports_chain(testnet));
 965                 assert_eq!(offer.chains(), vec![mainnet, testnet]);
 966                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![mainnet, testnet]));
 967         }
 968
 969         #[test]
 970         fn builds_offer_with_metadata() {
 971                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 972                         .metadata(vec![42; 32]).unwrap()
 973                         .build()
 974                         .unwrap();
 975                 assert_eq!(offer.metadata(), Some(&vec![42; 32]));
 976                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![42; 32]));
 977
 978                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 979                         .metadata(vec![42; 32]).unwrap()
 980                         .metadata(vec![43; 32]).unwrap()
 981                         .build()
 982                         .unwrap();
 983                 assert_eq!(offer.metadata(), Some(&vec![43; 32]));
 984                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![43; 32]));
 985         }
 986
 987         #[test]
 988         fn builds_offer_with_metadata_derived() {
 989                 let desc = "foo".to_string();
 990                 let node_id = recipient_pubkey();
 991                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
 992                 let entropy = FixedEntropy {};
 993                 let secp_ctx = Secp256k1::new();
 994
 995                 let offer = OfferBuilder
 996                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
 997                         .amount_msats(1000)
 998                         .build().unwrap();
 999                 assert_eq!(offer.signing_pubkey(), node_id);
1000
1001                 let invoice_request = offer.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).is_ok());
1005
1006                 // Fails verification with altered offer field
1007                 let mut tlv_stream = offer.as_tlv_stream();
1008                 tlv_stream.amount = Some(100);
1009
1010                 let mut encoded_offer = Vec::new();
1011                 tlv_stream.write(&mut encoded_offer).unwrap();
1012
1013                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1014                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1015                         .build().unwrap()
1016                         .sign(payer_sign).unwrap();
1017                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1018
1019                 // Fails verification with altered metadata
1020                 let mut tlv_stream = offer.as_tlv_stream();
1021                 let metadata = tlv_stream.metadata.unwrap().iter().copied().rev().collect();
1022                 tlv_stream.metadata = Some(&metadata);
1023
1024                 let mut encoded_offer = Vec::new();
1025                 tlv_stream.write(&mut encoded_offer).unwrap();
1026
1027                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1028                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1029                         .build().unwrap()
1030                         .sign(payer_sign).unwrap();
1031                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1032         }
1033
1034         #[test]
1035         fn builds_offer_with_derived_signing_pubkey() {
1036                 let desc = "foo".to_string();
1037                 let node_id = recipient_pubkey();
1038                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1039                 let entropy = FixedEntropy {};
1040                 let secp_ctx = Secp256k1::new();
1041
1042                 let blinded_path = BlindedPath {
1043                         introduction_node_id: pubkey(40),
1044                         blinding_point: pubkey(41),
1045                         blinded_hops: vec![
1046                                 BlindedHop { blinded_node_id: pubkey(42), encrypted_payload: vec![0; 43] },
1047                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
1048                         ],
1049                 };
1050
1051                 let offer = OfferBuilder
1052                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
1053                         .amount_msats(1000)
1054                         .path(blinded_path)
1055                         .build().unwrap();
1056                 assert_ne!(offer.signing_pubkey(), node_id);
1057
1058                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1059                         .build().unwrap()
1060                         .sign(payer_sign).unwrap();
1061                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
1062
1063                 // Fails verification with altered offer field
1064                 let mut tlv_stream = offer.as_tlv_stream();
1065                 tlv_stream.amount = Some(100);
1066
1067                 let mut encoded_offer = Vec::new();
1068                 tlv_stream.write(&mut encoded_offer).unwrap();
1069
1070                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1071                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1072                         .build().unwrap()
1073                         .sign(payer_sign).unwrap();
1074                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1075
1076                 // Fails verification with altered signing pubkey
1077                 let mut tlv_stream = offer.as_tlv_stream();
1078                 let signing_pubkey = pubkey(1);
1079                 tlv_stream.node_id = Some(&signing_pubkey);
1080
1081                 let mut encoded_offer = Vec::new();
1082                 tlv_stream.write(&mut encoded_offer).unwrap();
1083
1084                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1085                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1086                         .build().unwrap()
1087                         .sign(payer_sign).unwrap();
1088                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1089         }
1090
1091         #[test]
1092         fn builds_offer_with_amount() {
1093                 let bitcoin_amount = Amount::Bitcoin { amount_msats: 1000 };
1094                 let currency_amount = Amount::Currency { iso4217_code: *b"USD", amount: 10 };
1095
1096                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1097                         .amount_msats(1000)
1098                         .build()
1099                         .unwrap();
1100                 let tlv_stream = offer.as_tlv_stream();
1101                 assert_eq!(offer.amount(), Some(&bitcoin_amount));
1102                 assert_eq!(tlv_stream.amount, Some(1000));
1103                 assert_eq!(tlv_stream.currency, None);
1104
1105                 let builder = OfferBuilder::new("foo".into(), pubkey(42))
1106                         .amount(currency_amount.clone());
1107                 let tlv_stream = builder.offer.as_tlv_stream();
1108                 assert_eq!(builder.offer.amount, Some(currency_amount.clone()));
1109                 assert_eq!(tlv_stream.amount, Some(10));
1110                 assert_eq!(tlv_stream.currency, Some(b"USD"));
1111                 match builder.build() {
1112                         Ok(_) => panic!("expected error"),
1113                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnsupportedCurrency),
1114                 }
1115
1116                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1117                         .amount(currency_amount.clone())
1118                         .amount(bitcoin_amount.clone())
1119                         .build()
1120                         .unwrap();
1121                 let tlv_stream = offer.as_tlv_stream();
1122                 assert_eq!(tlv_stream.amount, Some(1000));
1123                 assert_eq!(tlv_stream.currency, None);
1124
1125                 let invalid_amount = Amount::Bitcoin { amount_msats: MAX_VALUE_MSAT + 1 };
1126                 match OfferBuilder::new("foo".into(), pubkey(42)).amount(invalid_amount).build() {
1127                         Ok(_) => panic!("expected error"),
1128                         Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
1129                 }
1130         }
1131
1132         #[test]
1133         fn builds_offer_with_features() {
1134                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1135                         .features_unchecked(OfferFeatures::unknown())
1136                         .build()
1137                         .unwrap();
1138                 assert_eq!(offer.offer_features(), &OfferFeatures::unknown());
1139                 assert_eq!(offer.as_tlv_stream().features, Some(&OfferFeatures::unknown()));
1140
1141                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1142                         .features_unchecked(OfferFeatures::unknown())
1143                         .features_unchecked(OfferFeatures::empty())
1144                         .build()
1145                         .unwrap();
1146                 assert_eq!(offer.offer_features(), &OfferFeatures::empty());
1147                 assert_eq!(offer.as_tlv_stream().features, None);
1148         }
1149
1150         #[test]
1151         fn builds_offer_with_absolute_expiry() {
1152                 let future_expiry = Duration::from_secs(u64::max_value());
1153                 let past_expiry = Duration::from_secs(0);
1154
1155                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1156                         .absolute_expiry(future_expiry)
1157                         .build()
1158                         .unwrap();
1159                 #[cfg(feature = "std")]
1160                 assert!(!offer.is_expired());
1161                 assert_eq!(offer.absolute_expiry(), Some(future_expiry));
1162                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(future_expiry.as_secs()));
1163
1164                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1165                         .absolute_expiry(future_expiry)
1166                         .absolute_expiry(past_expiry)
1167                         .build()
1168                         .unwrap();
1169                 #[cfg(feature = "std")]
1170                 assert!(offer.is_expired());
1171                 assert_eq!(offer.absolute_expiry(), Some(past_expiry));
1172                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(past_expiry.as_secs()));
1173         }
1174
1175         #[test]
1176         fn builds_offer_with_paths() {
1177                 let paths = vec![
1178                         BlindedPath {
1179                                 introduction_node_id: pubkey(40),
1180                                 blinding_point: pubkey(41),
1181                                 blinded_hops: vec![
1182                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1183                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1184                                 ],
1185                         },
1186                         BlindedPath {
1187                                 introduction_node_id: pubkey(40),
1188                                 blinding_point: pubkey(41),
1189                                 blinded_hops: vec![
1190                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1191                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1192                                 ],
1193                         },
1194                 ];
1195
1196                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1197                         .path(paths[0].clone())
1198                         .path(paths[1].clone())
1199                         .build()
1200                         .unwrap();
1201                 let tlv_stream = offer.as_tlv_stream();
1202                 assert_eq!(offer.paths(), paths.as_slice());
1203                 assert_eq!(offer.signing_pubkey(), pubkey(42));
1204                 assert_ne!(pubkey(42), pubkey(44));
1205                 assert_eq!(tlv_stream.paths, Some(&paths));
1206                 assert_eq!(tlv_stream.node_id, Some(&pubkey(42)));
1207         }
1208
1209         #[test]
1210         fn builds_offer_with_issuer() {
1211                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1212                         .issuer("bar".into())
1213                         .build()
1214                         .unwrap();
1215                 assert_eq!(offer.issuer(), Some(PrintableString("bar")));
1216                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("bar")));
1217
1218                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1219                         .issuer("bar".into())
1220                         .issuer("baz".into())
1221                         .build()
1222                         .unwrap();
1223                 assert_eq!(offer.issuer(), Some(PrintableString("baz")));
1224                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("baz")));
1225         }
1226
1227         #[test]
1228         fn builds_offer_with_supported_quantity() {
1229                 let one = NonZeroU64::new(1).unwrap();
1230                 let ten = NonZeroU64::new(10).unwrap();
1231
1232                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1233                         .supported_quantity(Quantity::One)
1234                         .build()
1235                         .unwrap();
1236                 let tlv_stream = offer.as_tlv_stream();
1237                 assert_eq!(offer.supported_quantity(), Quantity::One);
1238                 assert_eq!(tlv_stream.quantity_max, None);
1239
1240                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1241                         .supported_quantity(Quantity::Unbounded)
1242                         .build()
1243                         .unwrap();
1244                 let tlv_stream = offer.as_tlv_stream();
1245                 assert_eq!(offer.supported_quantity(), Quantity::Unbounded);
1246                 assert_eq!(tlv_stream.quantity_max, Some(0));
1247
1248                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1249                         .supported_quantity(Quantity::Bounded(ten))
1250                         .build()
1251                         .unwrap();
1252                 let tlv_stream = offer.as_tlv_stream();
1253                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(ten));
1254                 assert_eq!(tlv_stream.quantity_max, Some(10));
1255
1256                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1257                         .supported_quantity(Quantity::Bounded(one))
1258                         .build()
1259                         .unwrap();
1260                 let tlv_stream = offer.as_tlv_stream();
1261                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(one));
1262                 assert_eq!(tlv_stream.quantity_max, Some(1));
1263
1264                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1265                         .supported_quantity(Quantity::Bounded(ten))
1266                         .supported_quantity(Quantity::One)
1267                         .build()
1268                         .unwrap();
1269                 let tlv_stream = offer.as_tlv_stream();
1270                 assert_eq!(offer.supported_quantity(), Quantity::One);
1271                 assert_eq!(tlv_stream.quantity_max, None);
1272         }
1273
1274         #[test]
1275         fn fails_requesting_invoice_with_unknown_required_features() {
1276                 match OfferBuilder::new("foo".into(), pubkey(42))
1277                         .features_unchecked(OfferFeatures::unknown())
1278                         .build().unwrap()
1279                         .request_invoice(vec![1; 32], pubkey(43))
1280                 {
1281                         Ok(_) => panic!("expected error"),
1282                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnknownRequiredFeatures),
1283                 }
1284         }
1285
1286         #[test]
1287         fn parses_offer_with_chains() {
1288                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1289                         .chain(Network::Bitcoin)
1290                         .chain(Network::Testnet)
1291                         .build()
1292                         .unwrap();
1293                 if let Err(e) = offer.to_string().parse::<Offer>() {
1294                         panic!("error parsing offer: {:?}", e);
1295                 }
1296         }
1297
1298         #[test]
1299         fn parses_offer_with_amount() {
1300                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1301                         .amount(Amount::Bitcoin { amount_msats: 1000 })
1302                         .build()
1303                         .unwrap();
1304                 if let Err(e) = offer.to_string().parse::<Offer>() {
1305                         panic!("error parsing offer: {:?}", e);
1306                 }
1307
1308                 let mut tlv_stream = offer.as_tlv_stream();
1309                 tlv_stream.amount = Some(1000);
1310                 tlv_stream.currency = Some(b"USD");
1311
1312                 let mut encoded_offer = Vec::new();
1313                 tlv_stream.write(&mut encoded_offer).unwrap();
1314
1315                 if let Err(e) = Offer::try_from(encoded_offer) {
1316                         panic!("error parsing offer: {:?}", e);
1317                 }
1318
1319                 let mut tlv_stream = offer.as_tlv_stream();
1320                 tlv_stream.amount = None;
1321                 tlv_stream.currency = Some(b"USD");
1322
1323                 let mut encoded_offer = Vec::new();
1324                 tlv_stream.write(&mut encoded_offer).unwrap();
1325
1326                 match Offer::try_from(encoded_offer) {
1327                         Ok(_) => panic!("expected error"),
1328                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingAmount)),
1329                 }
1330
1331                 let mut tlv_stream = offer.as_tlv_stream();
1332                 tlv_stream.amount = Some(MAX_VALUE_MSAT + 1);
1333                 tlv_stream.currency = None;
1334
1335                 let mut encoded_offer = Vec::new();
1336                 tlv_stream.write(&mut encoded_offer).unwrap();
1337
1338                 match Offer::try_from(encoded_offer) {
1339                         Ok(_) => panic!("expected error"),
1340                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InvalidAmount)),
1341                 }
1342         }
1343
1344         #[test]
1345         fn parses_offer_with_description() {
1346                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1347                 if let Err(e) = offer.to_string().parse::<Offer>() {
1348                         panic!("error parsing offer: {:?}", e);
1349                 }
1350
1351                 let mut tlv_stream = offer.as_tlv_stream();
1352                 tlv_stream.description = None;
1353
1354                 let mut encoded_offer = Vec::new();
1355                 tlv_stream.write(&mut encoded_offer).unwrap();
1356
1357                 match Offer::try_from(encoded_offer) {
1358                         Ok(_) => panic!("expected error"),
1359                         Err(e) => {
1360                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription));
1361                         },
1362                 }
1363         }
1364
1365         #[test]
1366         fn parses_offer_with_paths() {
1367                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1368                         .path(BlindedPath {
1369                                 introduction_node_id: pubkey(40),
1370                                 blinding_point: pubkey(41),
1371                                 blinded_hops: vec![
1372                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1373                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1374                                 ],
1375                         })
1376                         .path(BlindedPath {
1377                                 introduction_node_id: pubkey(40),
1378                                 blinding_point: pubkey(41),
1379                                 blinded_hops: vec![
1380                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1381                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1382                                 ],
1383                         })
1384                         .build()
1385                         .unwrap();
1386                 if let Err(e) = offer.to_string().parse::<Offer>() {
1387                         panic!("error parsing offer: {:?}", e);
1388                 }
1389
1390                 let mut builder = OfferBuilder::new("foo".into(), pubkey(42));
1391                 builder.offer.paths = Some(vec![]);
1392
1393                 let offer = builder.build().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_quantity() {
1401                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1402                         .supported_quantity(Quantity::One)
1403                         .build()
1404                         .unwrap();
1405                 if let Err(e) = offer.to_string().parse::<Offer>() {
1406                         panic!("error parsing offer: {:?}", e);
1407                 }
1408
1409                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1410                         .supported_quantity(Quantity::Unbounded)
1411                         .build()
1412                         .unwrap();
1413                 if let Err(e) = offer.to_string().parse::<Offer>() {
1414                         panic!("error parsing offer: {:?}", e);
1415                 }
1416
1417                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1418                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(10).unwrap()))
1419                         .build()
1420                         .unwrap();
1421                 if let Err(e) = offer.to_string().parse::<Offer>() {
1422                         panic!("error parsing offer: {:?}", e);
1423                 }
1424
1425                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1426                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(1).unwrap()))
1427                         .build()
1428                         .unwrap();
1429                 if let Err(e) = offer.to_string().parse::<Offer>() {
1430                         panic!("error parsing offer: {:?}", e);
1431                 }
1432         }
1433
1434         #[test]
1435         fn parses_offer_with_node_id() {
1436                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1437                 if let Err(e) = offer.to_string().parse::<Offer>() {
1438                         panic!("error parsing offer: {:?}", e);
1439                 }
1440
1441                 let mut tlv_stream = offer.as_tlv_stream();
1442                 tlv_stream.node_id = None;
1443
1444                 let mut encoded_offer = Vec::new();
1445                 tlv_stream.write(&mut encoded_offer).unwrap();
1446
1447                 match Offer::try_from(encoded_offer) {
1448                         Ok(_) => panic!("expected error"),
1449                         Err(e) => {
1450                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingSigningPubkey));
1451                         },
1452                 }
1453         }
1454
1455         #[test]
1456         fn fails_parsing_offer_with_extra_tlv_records() {
1457                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1458
1459                 let mut encoded_offer = Vec::new();
1460                 offer.write(&mut encoded_offer).unwrap();
1461                 BigSize(80).write(&mut encoded_offer).unwrap();
1462                 BigSize(32).write(&mut encoded_offer).unwrap();
1463                 [42u8; 32].write(&mut encoded_offer).unwrap();
1464
1465                 match Offer::try_from(encoded_offer) {
1466                         Ok(_) => panic!("expected error"),
1467                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1468                 }
1469         }
1470 }
1471
1472 #[cfg(test)]
1473 mod bech32_tests {
1474         use super::{Bolt12ParseError, Offer};
1475         use bitcoin::bech32;
1476         use crate::ln::msgs::DecodeError;
1477
1478         #[test]
1479         fn encodes_offer_as_bech32_without_checksum() {
1480                 let encoded_offer = "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg";
1481                 let offer = dbg!(encoded_offer.parse::<Offer>().unwrap());
1482                 let reencoded_offer = offer.to_string();
1483                 dbg!(reencoded_offer.parse::<Offer>().unwrap());
1484                 assert_eq!(reencoded_offer, encoded_offer);
1485         }
1486
1487         #[test]
1488         fn parses_bech32_encoded_offers() {
1489                 let offers = [
1490                         // BOLT 12 test vectors
1491                         "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1492                         "l+no1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1493                         "lno1pqps7sjqpgt+yzm3qv4uxzmtsd3jjqer9wd3hy6tsw3+5k7msjzfpy7nz5yqcn+ygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd+5xvxg",
1494                         "lno1pqps7sjqpgt+ yzm3qv4uxzmtsd3jjqer9wd3hy6tsw3+  5k7msjzfpy7nz5yqcn+\nygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd+\r\n 5xvxg",
1495                 ];
1496                 for encoded_offer in &offers {
1497                         if let Err(e) = encoded_offer.parse::<Offer>() {
1498                                 panic!("Invalid offer ({:?}): {}", e, encoded_offer);
1499                         }
1500                 }
1501         }
1502
1503         #[test]
1504         fn fails_parsing_bech32_encoded_offers_with_invalid_continuations() {
1505                 let offers = [
1506                         // BOLT 12 test vectors
1507                         "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg+",
1508                         "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg+ ",
1509                         "+lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1510                         "+ lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1511                         "ln++o1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1512                 ];
1513                 for encoded_offer in &offers {
1514                         match encoded_offer.parse::<Offer>() {
1515                                 Ok(_) => panic!("Valid offer: {}", encoded_offer),
1516                                 Err(e) => assert_eq!(e, Bolt12ParseError::InvalidContinuation),
1517                         }
1518                 }
1519
1520         }
1521
1522         #[test]
1523         fn fails_parsing_bech32_encoded_offer_with_invalid_hrp() {
1524                 let encoded_offer = "lni1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg";
1525                 match encoded_offer.parse::<Offer>() {
1526                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1527                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidBech32Hrp),
1528                 }
1529         }
1530
1531         #[test]
1532         fn fails_parsing_bech32_encoded_offer_with_invalid_bech32_data() {
1533                 let encoded_offer = "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxo";
1534                 match encoded_offer.parse::<Offer>() {
1535                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1536                         Err(e) => assert_eq!(e, Bolt12ParseError::Bech32(bech32::Error::InvalidChar('o'))),
1537                 }
1538         }
1539
1540         #[test]
1541         fn fails_parsing_bech32_encoded_offer_with_invalid_tlv_data() {
1542                 let encoded_offer = "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxgqqqqq";
1543                 match encoded_offer.parse::<Offer>() {
1544                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1545                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1546                 }
1547         }
1548 }