_ 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 impl Offer {
 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<ChainHash> {
 369                 self.contents.chains()
 370         }
 371
 372         pub(super) fn implied_chain(&self) -> ChainHash {
 373                 self.contents.implied_chain()
 374         }
 375
 376         /// Returns whether the given chain is supported by the offer.
 377         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 378                 self.contents.supports_chain(chain)
 379         }
 380
 381         // TODO: Link to corresponding method in `InvoiceRequest`.
 382         /// Opaque bytes set by the originator. Useful for authentication and validating fields since it
 383         /// is reflected in `invoice_request` messages along with all the other fields from the `offer`.
 384         pub fn metadata(&self) -> Option<&Vec<u8>> {
 385                 self.contents.metadata()
 386         }
 387
 388         /// The minimum amount required for a successful payment of a single item.
 389         pub fn amount(&self) -> Option<&Amount> {
 390                 self.contents.amount()
 391         }
 392
 393         /// A complete description of the purpose of the payment. Intended to be displayed to the user
 394         /// but with the caveat that it has not been verified in any way.
 395         pub fn description(&self) -> PrintableString {
 396                 self.contents.description()
 397         }
 398
 399         /// Features pertaining to the offer.
 400         pub fn features(&self) -> &OfferFeatures {
 401                 &self.contents.features
 402         }
 403
 404         /// Duration since the Unix epoch when an invoice should no longer be requested.
 405         ///
 406         /// If `None`, the offer does not expire.
 407         pub fn absolute_expiry(&self) -> Option<Duration> {
 408                 self.contents.absolute_expiry
 409         }
 410
 411         /// Whether the offer has expired.
 412         #[cfg(feature = "std")]
 413         pub fn is_expired(&self) -> bool {
 414                 self.contents.is_expired()
 415         }
 416
 417         /// The issuer of the offer, possibly beginning with `user@domain` or `domain`. Intended to be
 418         /// displayed to the user but with the caveat that it has not been verified in any way.
 419         pub fn issuer(&self) -> Option<PrintableString> {
 420                 self.contents.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 421         }
 422
 423         /// Paths to the recipient originating from publicly reachable nodes. Blinded paths provide
 424         /// recipient privacy by obfuscating its node id.
 425         pub fn paths(&self) -> &[BlindedPath] {
 426                 self.contents.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 427         }
 428
 429         /// The quantity of items supported.
 430         pub fn supported_quantity(&self) -> Quantity {
 431                 self.contents.supported_quantity()
 432         }
 433
 434         /// Returns whether the given quantity is valid for the offer.
 435         pub fn is_valid_quantity(&self, quantity: u64) -> bool {
 436                 self.contents.is_valid_quantity(quantity)
 437         }
 438
 439         /// Returns whether a quantity is expected in an [`InvoiceRequest`] for the offer.
 440         ///
 441         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 442         pub fn expects_quantity(&self) -> bool {
 443                 self.contents.expects_quantity()
 444         }
 445
 446         /// The public key used by the recipient to sign invoices.
 447         pub fn signing_pubkey(&self) -> PublicKey {
 448                 self.contents.signing_pubkey()
 449         }
 450
 451         /// Similar to [`Offer::request_invoice`] except it:
 452         /// - derives the [`InvoiceRequest::payer_id`] such that a different key can be used for each
 453         ///   request, and
 454         /// - sets the [`InvoiceRequest::metadata`] when [`InvoiceRequestBuilder::build`] is called such
 455         ///   that it can be used by [`Bolt12Invoice::verify`] to determine if the invoice was requested
 456         ///   using a base [`ExpandedKey`] from which the payer id was derived.
 457         ///
 458         /// Useful to protect the sender's privacy.
 459         ///
 460         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 461         ///
 462         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 463         /// [`InvoiceRequest::metadata`]: crate::offers::invoice_request::InvoiceRequest::metadata
 464         /// [`Bolt12Invoice::verify`]: crate::offers::invoice::Bolt12Invoice::verify
 465         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 466         pub fn request_invoice_deriving_payer_id<'a, 'b, ES: Deref, T: secp256k1::Signing>(
 467                 &'a self, expanded_key: &ExpandedKey, entropy_source: ES, secp_ctx: &'b Secp256k1<T>
 468         ) -> Result<InvoiceRequestBuilder<'a, 'b, DerivedPayerId, T>, Bolt12SemanticError>
 469         where
 470                 ES::Target: EntropySource,
 471         {
 472                 if self.features().requires_unknown_bits() {
 473                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 474                 }
 475
 476                 Ok(InvoiceRequestBuilder::deriving_payer_id(self, expanded_key, entropy_source, secp_ctx))
 477         }
 478
 479         /// Similar to [`Offer::request_invoice_deriving_payer_id`] except uses `payer_id` for the
 480         /// [`InvoiceRequest::payer_id`] instead of deriving a different key for each request.
 481         ///
 482         /// Useful for recurring payments using the same `payer_id` with different invoices.
 483         ///
 484         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 485         ///
 486         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 487         pub fn request_invoice_deriving_metadata<ES: Deref>(
 488                 &self, payer_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES
 489         ) -> Result<InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>, Bolt12SemanticError>
 490         where
 491                 ES::Target: EntropySource,
 492         {
 493                 if self.features().requires_unknown_bits() {
 494                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 495                 }
 496
 497                 Ok(InvoiceRequestBuilder::deriving_metadata(self, payer_id, expanded_key, entropy_source))
 498         }
 499
 500         /// Creates an [`InvoiceRequestBuilder`] for the offer with the given `metadata` and `payer_id`,
 501         /// which will be reflected in the `Bolt12Invoice` response.
 502         ///
 503         /// The `metadata` is useful for including information about the derivation of `payer_id` such
 504         /// that invoice response handling can be stateless. Also serves as payer-provided entropy while
 505         /// hashing in the signature calculation.
 506         ///
 507         /// This should not leak any information such as by using a simple BIP-32 derivation path.
 508         /// Otherwise, payments may be correlated.
 509         ///
 510         /// Errors if the offer contains unknown required features.
 511         ///
 512         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 513         ///
 514         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 515         pub fn request_invoice(
 516                 &self, metadata: Vec<u8>, payer_id: PublicKey
 517         ) -> Result<InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>, Bolt12SemanticError> {
 518                 if self.features().requires_unknown_bits() {
 519                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 520                 }
 521
 522                 Ok(InvoiceRequestBuilder::new(self, metadata, payer_id))
 523         }
 524
 525         #[cfg(test)]
 526         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 527                 self.contents.as_tlv_stream()
 528         }
 529 }
 530
 531 impl AsRef<[u8]> for Offer {
 532         fn as_ref(&self) -> &[u8] {
 533                 &self.bytes
 534         }
 535 }
 536
 537 impl OfferContents {
 538         pub fn chains(&self) -> Vec<ChainHash> {
 539                 self.chains.as_ref().cloned().unwrap_or_else(|| vec![self.implied_chain()])
 540         }
 541
 542         pub fn implied_chain(&self) -> ChainHash {
 543                 ChainHash::using_genesis_block(Network::Bitcoin)
 544         }
 545
 546         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 547                 self.chains().contains(&chain)
 548         }
 549
 550         pub fn metadata(&self) -> Option<&Vec<u8>> {
 551                 self.metadata.as_ref().and_then(|metadata| metadata.as_bytes())
 552         }
 553
 554         pub fn description(&self) -> PrintableString {
 555                 PrintableString(&self.description)
 556         }
 557
 558         #[cfg(feature = "std")]
 559         pub(super) fn is_expired(&self) -> bool {
 560                 match self.absolute_expiry {
 561                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
 562                                 Ok(elapsed) => elapsed > seconds_from_epoch,
 563                                 Err(_) => false,
 564                         },
 565                         None => false,
 566                 }
 567         }
 568
 569         pub fn amount(&self) -> Option<&Amount> {
 570                 self.amount.as_ref()
 571         }
 572
 573         pub(super) fn check_amount_msats_for_quantity(
 574                 &self, amount_msats: Option<u64>, quantity: Option<u64>
 575         ) -> Result<(), Bolt12SemanticError> {
 576                 let offer_amount_msats = match self.amount {
 577                         None => 0,
 578                         Some(Amount::Bitcoin { amount_msats }) => amount_msats,
 579                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 580                 };
 581
 582                 if !self.expects_quantity() || quantity.is_some() {
 583                         let expected_amount_msats = offer_amount_msats.checked_mul(quantity.unwrap_or(1))
 584                                 .ok_or(Bolt12SemanticError::InvalidAmount)?;
 585                         let amount_msats = amount_msats.unwrap_or(expected_amount_msats);
 586
 587                         if amount_msats < expected_amount_msats {
 588                                 return Err(Bolt12SemanticError::InsufficientAmount);
 589                         }
 590
 591                         if amount_msats > MAX_VALUE_MSAT {
 592                                 return Err(Bolt12SemanticError::InvalidAmount);
 593                         }
 594                 }
 595
 596                 Ok(())
 597         }
 598
 599         pub fn supported_quantity(&self) -> Quantity {
 600                 self.supported_quantity
 601         }
 602
 603         pub(super) fn check_quantity(&self, quantity: Option<u64>) -> Result<(), Bolt12SemanticError> {
 604                 let expects_quantity = self.expects_quantity();
 605                 match quantity {
 606                         None if expects_quantity => Err(Bolt12SemanticError::MissingQuantity),
 607                         Some(_) if !expects_quantity => Err(Bolt12SemanticError::UnexpectedQuantity),
 608                         Some(quantity) if !self.is_valid_quantity(quantity) => {
 609                                 Err(Bolt12SemanticError::InvalidQuantity)
 610                         },
 611                         _ => Ok(()),
 612                 }
 613         }
 614
 615         fn is_valid_quantity(&self, quantity: u64) -> bool {
 616                 match self.supported_quantity {
 617                         Quantity::Bounded(n) => quantity <= n.get(),
 618                         Quantity::Unbounded => quantity > 0,
 619                         Quantity::One => quantity == 1,
 620                 }
 621         }
 622
 623         fn expects_quantity(&self) -> bool {
 624                 match self.supported_quantity {
 625                         Quantity::Bounded(_) => true,
 626                         Quantity::Unbounded => true,
 627                         Quantity::One => false,
 628                 }
 629         }
 630
 631         pub(super) fn signing_pubkey(&self) -> PublicKey {
 632                 self.signing_pubkey
 633         }
 634
 635         /// Verifies that the offer metadata was produced from the offer in the TLV stream.
 636         pub(super) fn verify<T: secp256k1::Signing>(
 637                 &self, bytes: &[u8], key: &ExpandedKey, secp_ctx: &Secp256k1<T>
 638         ) -> Result<Option<KeyPair>, ()> {
 639                 match self.metadata() {
 640                         Some(metadata) => {
 641                                 let tlv_stream = TlvStream::new(bytes).range(OFFER_TYPES).filter(|record| {
 642                                         match record.r#type {
 643                                                 OFFER_METADATA_TYPE => false,
 644                                                 OFFER_NODE_ID_TYPE => !self.metadata.as_ref().unwrap().derives_keys(),
 645                                                 _ => true,
 646                                         }
 647                                 });
 648                                 signer::verify_metadata(
 649                                         metadata, key, IV_BYTES, self.signing_pubkey(), tlv_stream, secp_ctx
 650                                 )
 651                         },
 652                         None => Err(()),
 653                 }
 654         }
 655
 656         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 657                 let (currency, amount) = match &self.amount {
 658                         None => (None, None),
 659                         Some(Amount::Bitcoin { amount_msats }) => (None, Some(*amount_msats)),
 660                         Some(Amount::Currency { iso4217_code, amount }) => (
 661                                 Some(iso4217_code), Some(*amount)
 662                         ),
 663                 };
 664
 665                 let features = {
 666                         if self.features == OfferFeatures::empty() { None } else { Some(&self.features) }
 667                 };
 668
 669                 OfferTlvStreamRef {
 670                         chains: self.chains.as_ref(),
 671                         metadata: self.metadata(),
 672                         currency,
 673                         amount,
 674                         description: Some(&self.description),
 675                         features,
 676                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 677                         paths: self.paths.as_ref(),
 678                         issuer: self.issuer.as_ref(),
 679                         quantity_max: self.supported_quantity.to_tlv_record(),
 680                         node_id: Some(&self.signing_pubkey),
 681                 }
 682         }
 683 }
 684
 685 impl Writeable for Offer {
 686         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 687                 WithoutLength(&self.bytes).write(writer)
 688         }
 689 }
 690
 691 impl Writeable for OfferContents {
 692         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 693                 self.as_tlv_stream().write(writer)
 694         }
 695 }
 696
 697 /// The minimum amount required for an item in an [`Offer`], denominated in either bitcoin or
 698 /// another currency.
 699 #[derive(Clone, Debug, PartialEq)]
 700 pub enum Amount {
 701         /// An amount of bitcoin.
 702         Bitcoin {
 703                 /// The amount in millisatoshi.
 704                 amount_msats: u64,
 705         },
 706         /// An amount of currency specified using ISO 4712.
 707         Currency {
 708                 /// The currency that the amount is denominated in.
 709                 ///
 710                 /// This is not exported to bindings users as bindings have troubles with type aliases to
 711                 /// byte arrays.
 712                 iso4217_code: CurrencyCode,
 713                 /// The amount in the currency unit adjusted by the ISO 4712 exponent (e.g., USD cents).
 714                 amount: u64,
 715         },
 716 }
 717
 718 /// An ISO 4712 three-letter currency code (e.g., USD).
 719 pub(crate) type CurrencyCode = [u8; 3];
 720
 721 /// Quantity of items supported by an [`Offer`].
 722 #[derive(Clone, Copy, Debug, PartialEq)]
 723 pub enum Quantity {
 724         /// Up to a specific number of items (inclusive). Use when more than one item can be requested
 725         /// but is limited (e.g., because of per customer or inventory limits).
 726         ///
 727         /// May be used with `NonZeroU64::new(1)` but prefer to use [`Quantity::One`] if only one item
 728         /// is supported.
 729         Bounded(/// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 730                 NonZeroU64),
 731         /// One or more items. Use when more than one item can be requested without any limit.
 732         Unbounded,
 733         /// Only one item. Use when only a single item can be requested.
 734         One,
 735 }
 736
 737 impl Quantity {
 738         fn to_tlv_record(&self) -> Option<u64> {
 739                 match self {
 740                         Quantity::Bounded(n) => Some(n.get()),
 741                         Quantity::Unbounded => Some(0),
 742                         Quantity::One => None,
 743                 }
 744         }
 745 }
 746
 747 /// Valid type range for offer TLV records.
 748 pub(super) const OFFER_TYPES: core::ops::Range<u64> = 1..80;
 749
 750 /// TLV record type for [`Offer::metadata`].
 751 const OFFER_METADATA_TYPE: u64 = 4;
 752
 753 /// TLV record type for [`Offer::signing_pubkey`].
 754 const OFFER_NODE_ID_TYPE: u64 = 22;
 755
 756 tlv_stream!(OfferTlvStream, OfferTlvStreamRef, OFFER_TYPES, {
 757         (2, chains: (Vec<ChainHash>, WithoutLength)),
 758         (OFFER_METADATA_TYPE, metadata: (Vec<u8>, WithoutLength)),
 759         (6, currency: CurrencyCode),
 760         (8, amount: (u64, HighZeroBytesDroppedBigSize)),
 761         (10, description: (String, WithoutLength)),
 762         (12, features: (OfferFeatures, WithoutLength)),
 763         (14, absolute_expiry: (u64, HighZeroBytesDroppedBigSize)),
 764         (16, paths: (Vec<BlindedPath>, WithoutLength)),
 765         (18, issuer: (String, WithoutLength)),
 766         (20, quantity_max: (u64, HighZeroBytesDroppedBigSize)),
 767         (OFFER_NODE_ID_TYPE, node_id: PublicKey),
 768 });
 769
 770 impl Bech32Encode for Offer {
 771         const BECH32_HRP: &'static str = "lno";
 772 }
 773
 774 impl FromStr for Offer {
 775         type Err = Bolt12ParseError;
 776
 777         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 778                 Self::from_bech32_str(s)
 779         }
 780 }
 781
 782 impl TryFrom<Vec<u8>> for Offer {
 783         type Error = Bolt12ParseError;
 784
 785         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 786                 let offer = ParsedMessage::<OfferTlvStream>::try_from(bytes)?;
 787                 let ParsedMessage { bytes, tlv_stream } = offer;
 788                 let contents = OfferContents::try_from(tlv_stream)?;
 789                 Ok(Offer { bytes, contents })
 790         }
 791 }
 792
 793 impl TryFrom<OfferTlvStream> for OfferContents {
 794         type Error = Bolt12SemanticError;
 795
 796         fn try_from(tlv_stream: OfferTlvStream) -> Result<Self, Self::Error> {
 797                 let OfferTlvStream {
 798                         chains, metadata, currency, amount, description, features, absolute_expiry, paths,
 799                         issuer, quantity_max, node_id,
 800                 } = tlv_stream;
 801
 802                 let metadata = metadata.map(|metadata| Metadata::Bytes(metadata));
 803
 804                 let amount = match (currency, amount) {
 805                         (None, None) => None,
 806                         (None, Some(amount_msats)) if amount_msats > MAX_VALUE_MSAT => {
 807                                 return Err(Bolt12SemanticError::InvalidAmount);
 808                         },
 809                         (None, Some(amount_msats)) => Some(Amount::Bitcoin { amount_msats }),
 810                         (Some(_), None) => return Err(Bolt12SemanticError::MissingAmount),
 811                         (Some(iso4217_code), Some(amount)) => Some(Amount::Currency { iso4217_code, amount }),
 812                 };
 813
 814                 let description = match description {
 815                         None => return Err(Bolt12SemanticError::MissingDescription),
 816                         Some(description) => description,
 817                 };
 818
 819                 let features = features.unwrap_or_else(OfferFeatures::empty);
 820
 821                 let absolute_expiry = absolute_expiry
 822                         .map(|seconds_from_epoch| Duration::from_secs(seconds_from_epoch));
 823
 824                 let supported_quantity = match quantity_max {
 825                         None => Quantity::One,
 826                         Some(0) => Quantity::Unbounded,
 827                         Some(n) => Quantity::Bounded(NonZeroU64::new(n).unwrap()),
 828                 };
 829
 830                 let signing_pubkey = match node_id {
 831                         None => return Err(Bolt12SemanticError::MissingSigningPubkey),
 832                         Some(node_id) => node_id,
 833                 };
 834
 835                 Ok(OfferContents {
 836                         chains, metadata, amount, description, features, absolute_expiry, issuer, paths,
 837                         supported_quantity, signing_pubkey,
 838                 })
 839         }
 840 }
 841
 842 impl core::fmt::Display for Offer {
 843         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 844                 self.fmt_bech32_str(f)
 845         }
 846 }
 847
 848 #[cfg(test)]
 849 mod tests {
 850         use super::{Amount, Offer, OfferBuilder, OfferTlvStreamRef, Quantity};
 851
 852         use bitcoin::blockdata::constants::ChainHash;
 853         use bitcoin::network::constants::Network;
 854         use bitcoin::secp256k1::Secp256k1;
 855         use core::convert::TryFrom;
 856         use core::num::NonZeroU64;
 857         use core::time::Duration;
 858         use crate::blinded_path::{BlindedHop, BlindedPath};
 859         use crate::sign::KeyMaterial;
 860         use crate::ln::features::OfferFeatures;
 861         use crate::ln::inbound_payment::ExpandedKey;
 862         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 863         use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
 864         use crate::offers::test_utils::*;
 865         use crate::util::ser::{BigSize, Writeable};
 866         use crate::util::string::PrintableString;
 867
 868         #[test]
 869         fn builds_offer_with_defaults() {
 870                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
 871
 872                 let mut buffer = Vec::new();
 873                 offer.write(&mut buffer).unwrap();
 874
 875                 assert_eq!(offer.bytes, buffer.as_slice());
 876                 assert_eq!(offer.chains(), vec![ChainHash::using_genesis_block(Network::Bitcoin)]);
 877                 assert!(offer.supports_chain(ChainHash::using_genesis_block(Network::Bitcoin)));
 878                 assert_eq!(offer.metadata(), None);
 879                 assert_eq!(offer.amount(), None);
 880                 assert_eq!(offer.description(), PrintableString("foo"));
 881                 assert_eq!(offer.features(), &OfferFeatures::empty());
 882                 assert_eq!(offer.absolute_expiry(), None);
 883                 #[cfg(feature = "std")]
 884                 assert!(!offer.is_expired());
 885                 assert_eq!(offer.paths(), &[]);
 886                 assert_eq!(offer.issuer(), None);
 887                 assert_eq!(offer.supported_quantity(), Quantity::One);
 888                 assert_eq!(offer.signing_pubkey(), pubkey(42));
 889
 890                 assert_eq!(
 891                         offer.as_tlv_stream(),
 892                         OfferTlvStreamRef {
 893                                 chains: None,
 894                                 metadata: None,
 895                                 currency: None,
 896                                 amount: None,
 897                                 description: Some(&String::from("foo")),
 898                                 features: None,
 899                                 absolute_expiry: None,
 900                                 paths: None,
 901                                 issuer: None,
 902                                 quantity_max: None,
 903                                 node_id: Some(&pubkey(42)),
 904                         },
 905                 );
 906
 907                 if let Err(e) = Offer::try_from(buffer) {
 908                         panic!("error parsing offer: {:?}", e);
 909                 }
 910         }
 911
 912         #[test]
 913         fn builds_offer_with_chains() {
 914                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
 915                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
 916
 917                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 918                         .chain(Network::Bitcoin)
 919                         .build()
 920                         .unwrap();
 921                 assert!(offer.supports_chain(mainnet));
 922                 assert_eq!(offer.chains(), vec![mainnet]);
 923                 assert_eq!(offer.as_tlv_stream().chains, None);
 924
 925                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 926                         .chain(Network::Testnet)
 927                         .build()
 928                         .unwrap();
 929                 assert!(offer.supports_chain(testnet));
 930                 assert_eq!(offer.chains(), vec![testnet]);
 931                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 932
 933                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 934                         .chain(Network::Testnet)
 935                         .chain(Network::Testnet)
 936                         .build()
 937                         .unwrap();
 938                 assert!(offer.supports_chain(testnet));
 939                 assert_eq!(offer.chains(), vec![testnet]);
 940                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
 941
 942                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 943                         .chain(Network::Bitcoin)
 944                         .chain(Network::Testnet)
 945                         .build()
 946                         .unwrap();
 947                 assert!(offer.supports_chain(mainnet));
 948                 assert!(offer.supports_chain(testnet));
 949                 assert_eq!(offer.chains(), vec![mainnet, testnet]);
 950                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![mainnet, testnet]));
 951         }
 952
 953         #[test]
 954         fn builds_offer_with_metadata() {
 955                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 956                         .metadata(vec![42; 32]).unwrap()
 957                         .build()
 958                         .unwrap();
 959                 assert_eq!(offer.metadata(), Some(&vec![42; 32]));
 960                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![42; 32]));
 961
 962                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
 963                         .metadata(vec![42; 32]).unwrap()
 964                         .metadata(vec![43; 32]).unwrap()
 965                         .build()
 966                         .unwrap();
 967                 assert_eq!(offer.metadata(), Some(&vec![43; 32]));
 968                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![43; 32]));
 969         }
 970
 971         #[test]
 972         fn builds_offer_with_metadata_derived() {
 973                 let desc = "foo".to_string();
 974                 let node_id = recipient_pubkey();
 975                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
 976                 let entropy = FixedEntropy {};
 977                 let secp_ctx = Secp256k1::new();
 978
 979                 let offer = OfferBuilder
 980                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
 981                         .amount_msats(1000)
 982                         .build().unwrap();
 983                 assert_eq!(offer.signing_pubkey(), node_id);
 984
 985                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 986                         .build().unwrap()
 987                         .sign(payer_sign).unwrap();
 988                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
 989
 990                 // Fails verification with altered offer field
 991                 let mut tlv_stream = offer.as_tlv_stream();
 992                 tlv_stream.amount = Some(100);
 993
 994                 let mut encoded_offer = Vec::new();
 995                 tlv_stream.write(&mut encoded_offer).unwrap();
 996
 997                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
 998                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 999                         .build().unwrap()
1000                         .sign(payer_sign).unwrap();
1001                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1002
1003                 // Fails verification with altered metadata
1004                 let mut tlv_stream = offer.as_tlv_stream();
1005                 let metadata = tlv_stream.metadata.unwrap().iter().copied().rev().collect();
1006                 tlv_stream.metadata = Some(&metadata);
1007
1008                 let mut encoded_offer = Vec::new();
1009                 tlv_stream.write(&mut encoded_offer).unwrap();
1010
1011                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1012                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1013                         .build().unwrap()
1014                         .sign(payer_sign).unwrap();
1015                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1016         }
1017
1018         #[test]
1019         fn builds_offer_with_derived_signing_pubkey() {
1020                 let desc = "foo".to_string();
1021                 let node_id = recipient_pubkey();
1022                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1023                 let entropy = FixedEntropy {};
1024                 let secp_ctx = Secp256k1::new();
1025
1026                 let blinded_path = BlindedPath {
1027                         introduction_node_id: pubkey(40),
1028                         blinding_point: pubkey(41),
1029                         blinded_hops: vec![
1030                                 BlindedHop { blinded_node_id: pubkey(42), encrypted_payload: vec![0; 43] },
1031                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
1032                         ],
1033                 };
1034
1035                 let offer = OfferBuilder
1036                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
1037                         .amount_msats(1000)
1038                         .path(blinded_path)
1039                         .build().unwrap();
1040                 assert_ne!(offer.signing_pubkey(), node_id);
1041
1042                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1043                         .build().unwrap()
1044                         .sign(payer_sign).unwrap();
1045                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
1046
1047                 // Fails verification with altered offer field
1048                 let mut tlv_stream = offer.as_tlv_stream();
1049                 tlv_stream.amount = Some(100);
1050
1051                 let mut encoded_offer = Vec::new();
1052                 tlv_stream.write(&mut encoded_offer).unwrap();
1053
1054                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1055                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1056                         .build().unwrap()
1057                         .sign(payer_sign).unwrap();
1058                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1059
1060                 // Fails verification with altered signing pubkey
1061                 let mut tlv_stream = offer.as_tlv_stream();
1062                 let signing_pubkey = pubkey(1);
1063                 tlv_stream.node_id = Some(&signing_pubkey);
1064
1065                 let mut encoded_offer = Vec::new();
1066                 tlv_stream.write(&mut encoded_offer).unwrap();
1067
1068                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1069                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1070                         .build().unwrap()
1071                         .sign(payer_sign).unwrap();
1072                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1073         }
1074
1075         #[test]
1076         fn builds_offer_with_amount() {
1077                 let bitcoin_amount = Amount::Bitcoin { amount_msats: 1000 };
1078                 let currency_amount = Amount::Currency { iso4217_code: *b"USD", amount: 10 };
1079
1080                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1081                         .amount_msats(1000)
1082                         .build()
1083                         .unwrap();
1084                 let tlv_stream = offer.as_tlv_stream();
1085                 assert_eq!(offer.amount(), Some(&bitcoin_amount));
1086                 assert_eq!(tlv_stream.amount, Some(1000));
1087                 assert_eq!(tlv_stream.currency, None);
1088
1089                 let builder = OfferBuilder::new("foo".into(), pubkey(42))
1090                         .amount(currency_amount.clone());
1091                 let tlv_stream = builder.offer.as_tlv_stream();
1092                 assert_eq!(builder.offer.amount, Some(currency_amount.clone()));
1093                 assert_eq!(tlv_stream.amount, Some(10));
1094                 assert_eq!(tlv_stream.currency, Some(b"USD"));
1095                 match builder.build() {
1096                         Ok(_) => panic!("expected error"),
1097                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnsupportedCurrency),
1098                 }
1099
1100                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1101                         .amount(currency_amount.clone())
1102                         .amount(bitcoin_amount.clone())
1103                         .build()
1104                         .unwrap();
1105                 let tlv_stream = offer.as_tlv_stream();
1106                 assert_eq!(tlv_stream.amount, Some(1000));
1107                 assert_eq!(tlv_stream.currency, None);
1108
1109                 let invalid_amount = Amount::Bitcoin { amount_msats: MAX_VALUE_MSAT + 1 };
1110                 match OfferBuilder::new("foo".into(), pubkey(42)).amount(invalid_amount).build() {
1111                         Ok(_) => panic!("expected error"),
1112                         Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
1113                 }
1114         }
1115
1116         #[test]
1117         fn builds_offer_with_features() {
1118                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1119                         .features_unchecked(OfferFeatures::unknown())
1120                         .build()
1121                         .unwrap();
1122                 assert_eq!(offer.features(), &OfferFeatures::unknown());
1123                 assert_eq!(offer.as_tlv_stream().features, Some(&OfferFeatures::unknown()));
1124
1125                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1126                         .features_unchecked(OfferFeatures::unknown())
1127                         .features_unchecked(OfferFeatures::empty())
1128                         .build()
1129                         .unwrap();
1130                 assert_eq!(offer.features(), &OfferFeatures::empty());
1131                 assert_eq!(offer.as_tlv_stream().features, None);
1132         }
1133
1134         #[test]
1135         fn builds_offer_with_absolute_expiry() {
1136                 let future_expiry = Duration::from_secs(u64::max_value());
1137                 let past_expiry = Duration::from_secs(0);
1138
1139                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1140                         .absolute_expiry(future_expiry)
1141                         .build()
1142                         .unwrap();
1143                 #[cfg(feature = "std")]
1144                 assert!(!offer.is_expired());
1145                 assert_eq!(offer.absolute_expiry(), Some(future_expiry));
1146                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(future_expiry.as_secs()));
1147
1148                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1149                         .absolute_expiry(future_expiry)
1150                         .absolute_expiry(past_expiry)
1151                         .build()
1152                         .unwrap();
1153                 #[cfg(feature = "std")]
1154                 assert!(offer.is_expired());
1155                 assert_eq!(offer.absolute_expiry(), Some(past_expiry));
1156                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(past_expiry.as_secs()));
1157         }
1158
1159         #[test]
1160         fn builds_offer_with_paths() {
1161                 let paths = vec![
1162                         BlindedPath {
1163                                 introduction_node_id: pubkey(40),
1164                                 blinding_point: pubkey(41),
1165                                 blinded_hops: vec![
1166                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1167                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1168                                 ],
1169                         },
1170                         BlindedPath {
1171                                 introduction_node_id: pubkey(40),
1172                                 blinding_point: pubkey(41),
1173                                 blinded_hops: vec![
1174                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1175                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1176                                 ],
1177                         },
1178                 ];
1179
1180                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1181                         .path(paths[0].clone())
1182                         .path(paths[1].clone())
1183                         .build()
1184                         .unwrap();
1185                 let tlv_stream = offer.as_tlv_stream();
1186                 assert_eq!(offer.paths(), paths.as_slice());
1187                 assert_eq!(offer.signing_pubkey(), pubkey(42));
1188                 assert_ne!(pubkey(42), pubkey(44));
1189                 assert_eq!(tlv_stream.paths, Some(&paths));
1190                 assert_eq!(tlv_stream.node_id, Some(&pubkey(42)));
1191         }
1192
1193         #[test]
1194         fn builds_offer_with_issuer() {
1195                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1196                         .issuer("bar".into())
1197                         .build()
1198                         .unwrap();
1199                 assert_eq!(offer.issuer(), Some(PrintableString("bar")));
1200                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("bar")));
1201
1202                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1203                         .issuer("bar".into())
1204                         .issuer("baz".into())
1205                         .build()
1206                         .unwrap();
1207                 assert_eq!(offer.issuer(), Some(PrintableString("baz")));
1208                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("baz")));
1209         }
1210
1211         #[test]
1212         fn builds_offer_with_supported_quantity() {
1213                 let one = NonZeroU64::new(1).unwrap();
1214                 let ten = NonZeroU64::new(10).unwrap();
1215
1216                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1217                         .supported_quantity(Quantity::One)
1218                         .build()
1219                         .unwrap();
1220                 let tlv_stream = offer.as_tlv_stream();
1221                 assert_eq!(offer.supported_quantity(), Quantity::One);
1222                 assert_eq!(tlv_stream.quantity_max, None);
1223
1224                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1225                         .supported_quantity(Quantity::Unbounded)
1226                         .build()
1227                         .unwrap();
1228                 let tlv_stream = offer.as_tlv_stream();
1229                 assert_eq!(offer.supported_quantity(), Quantity::Unbounded);
1230                 assert_eq!(tlv_stream.quantity_max, Some(0));
1231
1232                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1233                         .supported_quantity(Quantity::Bounded(ten))
1234                         .build()
1235                         .unwrap();
1236                 let tlv_stream = offer.as_tlv_stream();
1237                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(ten));
1238                 assert_eq!(tlv_stream.quantity_max, Some(10));
1239
1240                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1241                         .supported_quantity(Quantity::Bounded(one))
1242                         .build()
1243                         .unwrap();
1244                 let tlv_stream = offer.as_tlv_stream();
1245                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(one));
1246                 assert_eq!(tlv_stream.quantity_max, Some(1));
1247
1248                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1249                         .supported_quantity(Quantity::Bounded(ten))
1250                         .supported_quantity(Quantity::One)
1251                         .build()
1252                         .unwrap();
1253                 let tlv_stream = offer.as_tlv_stream();
1254                 assert_eq!(offer.supported_quantity(), Quantity::One);
1255                 assert_eq!(tlv_stream.quantity_max, None);
1256         }
1257
1258         #[test]
1259         fn fails_requesting_invoice_with_unknown_required_features() {
1260                 match OfferBuilder::new("foo".into(), pubkey(42))
1261                         .features_unchecked(OfferFeatures::unknown())
1262                         .build().unwrap()
1263                         .request_invoice(vec![1; 32], pubkey(43))
1264                 {
1265                         Ok(_) => panic!("expected error"),
1266                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnknownRequiredFeatures),
1267                 }
1268         }
1269
1270         #[test]
1271         fn parses_offer_with_chains() {
1272                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1273                         .chain(Network::Bitcoin)
1274                         .chain(Network::Testnet)
1275                         .build()
1276                         .unwrap();
1277                 if let Err(e) = offer.to_string().parse::<Offer>() {
1278                         panic!("error parsing offer: {:?}", e);
1279                 }
1280         }
1281
1282         #[test]
1283         fn parses_offer_with_amount() {
1284                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1285                         .amount(Amount::Bitcoin { amount_msats: 1000 })
1286                         .build()
1287                         .unwrap();
1288                 if let Err(e) = offer.to_string().parse::<Offer>() {
1289                         panic!("error parsing offer: {:?}", e);
1290                 }
1291
1292                 let mut tlv_stream = offer.as_tlv_stream();
1293                 tlv_stream.amount = Some(1000);
1294                 tlv_stream.currency = Some(b"USD");
1295
1296                 let mut encoded_offer = Vec::new();
1297                 tlv_stream.write(&mut encoded_offer).unwrap();
1298
1299                 if let Err(e) = Offer::try_from(encoded_offer) {
1300                         panic!("error parsing offer: {:?}", e);
1301                 }
1302
1303                 let mut tlv_stream = offer.as_tlv_stream();
1304                 tlv_stream.amount = None;
1305                 tlv_stream.currency = Some(b"USD");
1306
1307                 let mut encoded_offer = Vec::new();
1308                 tlv_stream.write(&mut encoded_offer).unwrap();
1309
1310                 match Offer::try_from(encoded_offer) {
1311                         Ok(_) => panic!("expected error"),
1312                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingAmount)),
1313                 }
1314
1315                 let mut tlv_stream = offer.as_tlv_stream();
1316                 tlv_stream.amount = Some(MAX_VALUE_MSAT + 1);
1317                 tlv_stream.currency = None;
1318
1319                 let mut encoded_offer = Vec::new();
1320                 tlv_stream.write(&mut encoded_offer).unwrap();
1321
1322                 match Offer::try_from(encoded_offer) {
1323                         Ok(_) => panic!("expected error"),
1324                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InvalidAmount)),
1325                 }
1326         }
1327
1328         #[test]
1329         fn parses_offer_with_description() {
1330                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1331                 if let Err(e) = offer.to_string().parse::<Offer>() {
1332                         panic!("error parsing offer: {:?}", e);
1333                 }
1334
1335                 let mut tlv_stream = offer.as_tlv_stream();
1336                 tlv_stream.description = None;
1337
1338                 let mut encoded_offer = Vec::new();
1339                 tlv_stream.write(&mut encoded_offer).unwrap();
1340
1341                 match Offer::try_from(encoded_offer) {
1342                         Ok(_) => panic!("expected error"),
1343                         Err(e) => {
1344                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription));
1345                         },
1346                 }
1347         }
1348
1349         #[test]
1350         fn parses_offer_with_paths() {
1351                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1352                         .path(BlindedPath {
1353                                 introduction_node_id: pubkey(40),
1354                                 blinding_point: pubkey(41),
1355                                 blinded_hops: vec![
1356                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1357                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1358                                 ],
1359                         })
1360                         .path(BlindedPath {
1361                                 introduction_node_id: pubkey(40),
1362                                 blinding_point: pubkey(41),
1363                                 blinded_hops: vec![
1364                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1365                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1366                                 ],
1367                         })
1368                         .build()
1369                         .unwrap();
1370                 if let Err(e) = offer.to_string().parse::<Offer>() {
1371                         panic!("error parsing offer: {:?}", e);
1372                 }
1373
1374                 let mut builder = OfferBuilder::new("foo".into(), pubkey(42));
1375                 builder.offer.paths = Some(vec![]);
1376
1377                 let offer = builder.build().unwrap();
1378                 if let Err(e) = offer.to_string().parse::<Offer>() {
1379                         panic!("error parsing offer: {:?}", e);
1380                 }
1381         }
1382
1383         #[test]
1384         fn parses_offer_with_quantity() {
1385                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1386                         .supported_quantity(Quantity::One)
1387                         .build()
1388                         .unwrap();
1389                 if let Err(e) = offer.to_string().parse::<Offer>() {
1390                         panic!("error parsing offer: {:?}", e);
1391                 }
1392
1393                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1394                         .supported_quantity(Quantity::Unbounded)
1395                         .build()
1396                         .unwrap();
1397                 if let Err(e) = offer.to_string().parse::<Offer>() {
1398                         panic!("error parsing offer: {:?}", e);
1399                 }
1400
1401                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1402                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(10).unwrap()))
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::Bounded(NonZeroU64::new(1).unwrap()))
1411                         .build()
1412                         .unwrap();
1413                 if let Err(e) = offer.to_string().parse::<Offer>() {
1414                         panic!("error parsing offer: {:?}", e);
1415                 }
1416         }
1417
1418         #[test]
1419         fn parses_offer_with_node_id() {
1420                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1421                 if let Err(e) = offer.to_string().parse::<Offer>() {
1422                         panic!("error parsing offer: {:?}", e);
1423                 }
1424
1425                 let mut tlv_stream = offer.as_tlv_stream();
1426                 tlv_stream.node_id = None;
1427
1428                 let mut encoded_offer = Vec::new();
1429                 tlv_stream.write(&mut encoded_offer).unwrap();
1430
1431                 match Offer::try_from(encoded_offer) {
1432                         Ok(_) => panic!("expected error"),
1433                         Err(e) => {
1434                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingSigningPubkey));
1435                         },
1436                 }
1437         }
1438
1439         #[test]
1440         fn fails_parsing_offer_with_extra_tlv_records() {
1441                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1442
1443                 let mut encoded_offer = Vec::new();
1444                 offer.write(&mut encoded_offer).unwrap();
1445                 BigSize(80).write(&mut encoded_offer).unwrap();
1446                 BigSize(32).write(&mut encoded_offer).unwrap();
1447                 [42u8; 32].write(&mut encoded_offer).unwrap();
1448
1449                 match Offer::try_from(encoded_offer) {
1450                         Ok(_) => panic!("expected error"),
1451                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1452                 }
1453         }
1454 }
1455
1456 #[cfg(test)]
1457 mod bech32_tests {
1458         use super::{Bolt12ParseError, Offer};
1459         use bitcoin::bech32;
1460         use crate::ln::msgs::DecodeError;
1461
1462         #[test]
1463         fn encodes_offer_as_bech32_without_checksum() {
1464                 let encoded_offer = "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg";
1465                 let offer = dbg!(encoded_offer.parse::<Offer>().unwrap());
1466                 let reencoded_offer = offer.to_string();
1467                 dbg!(reencoded_offer.parse::<Offer>().unwrap());
1468                 assert_eq!(reencoded_offer, encoded_offer);
1469         }
1470
1471         #[test]
1472         fn parses_bech32_encoded_offers() {
1473                 let offers = [
1474                         // BOLT 12 test vectors
1475                         "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1476                         "l+no1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1477                         "lno1pqps7sjqpgt+yzm3qv4uxzmtsd3jjqer9wd3hy6tsw3+5k7msjzfpy7nz5yqcn+ygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd+5xvxg",
1478                         "lno1pqps7sjqpgt+ yzm3qv4uxzmtsd3jjqer9wd3hy6tsw3+  5k7msjzfpy7nz5yqcn+\nygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd+\r\n 5xvxg",
1479                 ];
1480                 for encoded_offer in &offers {
1481                         if let Err(e) = encoded_offer.parse::<Offer>() {
1482                                 panic!("Invalid offer ({:?}): {}", e, encoded_offer);
1483                         }
1484                 }
1485         }
1486
1487         #[test]
1488         fn fails_parsing_bech32_encoded_offers_with_invalid_continuations() {
1489                 let offers = [
1490                         // BOLT 12 test vectors
1491                         "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg+",
1492                         "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg+ ",
1493                         "+lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1494                         "+ lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1495                         "ln++o1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1496                 ];
1497                 for encoded_offer in &offers {
1498                         match encoded_offer.parse::<Offer>() {
1499                                 Ok(_) => panic!("Valid offer: {}", encoded_offer),
1500                                 Err(e) => assert_eq!(e, Bolt12ParseError::InvalidContinuation),
1501                         }
1502                 }
1503
1504         }
1505
1506         #[test]
1507         fn fails_parsing_bech32_encoded_offer_with_invalid_hrp() {
1508                 let encoded_offer = "lni1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg";
1509                 match encoded_offer.parse::<Offer>() {
1510                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1511                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidBech32Hrp),
1512                 }
1513         }
1514
1515         #[test]
1516         fn fails_parsing_bech32_encoded_offer_with_invalid_bech32_data() {
1517                 let encoded_offer = "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxo";
1518                 match encoded_offer.parse::<Offer>() {
1519                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1520                         Err(e) => assert_eq!(e, Bolt12ParseError::Bech32(bech32::Error::InvalidChar('o'))),
1521                 }
1522         }
1523
1524         #[test]
1525         fn fails_parsing_bech32_encoded_offer_with_invalid_tlv_data() {
1526                 let encoded_offer = "lno1pqps7sjqpgtyzm3qv4uxzmtsd3jjqer9wd3hy6tsw35k7msjzfpy7nz5yqcnygrfdej82um5wf5k2uckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxgqqqqq";
1527                 match encoded_offer.parse::<Offer>() {
1528                         Ok(_) => panic!("Valid offer: {}", encoded_offer),
1529                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1530                 }
1531         }
1532 }