_ 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 //! # Example
  17 //!
  18 //! ```
  19 //! extern crate bitcoin;
  20 //! extern crate core;
  21 //! extern crate lightning;
  22 //!
  23 //! use core::convert::TryFrom;
  24 //! use core::num::NonZeroU64;
  25 //! use core::time::Duration;
  26 //!
  27 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
  28 //! use lightning::offers::offer::{Offer, OfferBuilder, Quantity};
  29 //! use lightning::offers::parse::Bolt12ParseError;
  30 //! use lightning::util::ser::{Readable, Writeable};
  31 //!
  32 //! # use lightning::blinded_path::BlindedPath;
  33 //! # #[cfg(feature = "std")]
  34 //! # use std::time::SystemTime;
  35 //! #
  36 //! # fn create_blinded_path() -> BlindedPath { unimplemented!() }
  37 //! # fn create_another_blinded_path() -> BlindedPath { unimplemented!() }
  38 //! #
  39 //! # #[cfg(feature = "std")]
  40 //! # fn build() -> Result<(), Bolt12ParseError> {
  41 //! let secp_ctx = Secp256k1::new();
  42 //! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
  43 //! let pubkey = PublicKey::from(keys);
  44 //!
  45 //! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
  46 //! let offer = OfferBuilder::new("coffee, large".to_string(), pubkey)
  47 //!     .amount_msats(20_000)
  48 //!     .supported_quantity(Quantity::Unbounded)
  49 //!     .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
  50 //!     .issuer("Foo Bar".to_string())
  51 //!     .path(create_blinded_path())
  52 //!     .path(create_another_blinded_path())
  53 //!     .build()?;
  54 //!
  55 //! // Encode as a bech32 string for use in a QR code.
  56 //! let encoded_offer = offer.to_string();
  57 //!
  58 //! // Parse from a bech32 string after scanning from a QR code.
  59 //! let offer = encoded_offer.parse::<Offer>()?;
  60 //!
  61 //! // Encode offer as raw bytes.
  62 //! let mut bytes = Vec::new();
  63 //! offer.write(&mut bytes).unwrap();
  64 //!
  65 //! // Decode raw bytes into an offer.
  66 //! let offer = Offer::try_from(bytes)?;
  67 //! # Ok(())
  68 //! # }
  69 //! ```
  70 //!
  71 //! # Note
  72 //!
  73 //! If constructing an [`Offer`] for use with a [`ChannelManager`], use
  74 //! [`ChannelManager::create_offer_builder`] instead of [`OfferBuilder::new`].
  75 //!
  76 //! [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
  77 //! [`ChannelManager::create_offer_builder`]: crate::ln::channelmanager::ChannelManager::create_offer_builder
  78
  79 use bitcoin::blockdata::constants::ChainHash;
  80 use bitcoin::network::constants::Network;
  81 use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, self};
  82 use core::hash::{Hash, Hasher};
  83 use core::num::NonZeroU64;
  84 use core::ops::Deref;
  85 use core::str::FromStr;
  86 use core::time::Duration;
  87 use crate::sign::EntropySource;
  88 use crate::io;
  89 use crate::blinded_path::BlindedPath;
  90 use crate::ln::channelmanager::PaymentId;
  91 use crate::ln::features::OfferFeatures;
  92 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
  93 use crate::ln::msgs::MAX_VALUE_MSAT;
  94 use crate::offers::merkle::TlvStream;
  95 use crate::offers::parse::{Bech32Encode, Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
  96 use crate::offers::signer::{Metadata, MetadataMaterial, self};
  97 use crate::util::ser::{HighZeroBytesDroppedBigSize, WithoutLength, Writeable, Writer};
  98 use crate::util::string::PrintableString;
  99
 100 #[cfg(not(c_bindings))]
 101 use {
 102         crate::offers::invoice_request::{DerivedPayerId, ExplicitPayerId, InvoiceRequestBuilder},
 103 };
 104 #[cfg(c_bindings)]
 105 use {
 106         crate::offers::invoice_request::{InvoiceRequestWithDerivedPayerIdBuilder, InvoiceRequestWithExplicitPayerIdBuilder},
 107 };
 108
 109 #[allow(unused_imports)]
 110 use crate::prelude::*;
 111
 112 #[cfg(feature = "std")]
 113 use std::time::SystemTime;
 114
 115 pub(super) const IV_BYTES: &[u8; IV_LEN] = b"LDK Offer ~~~~~~";
 116
 117 /// Builds an [`Offer`] for the "offer to be paid" flow.
 118 ///
 119 /// See [module-level documentation] for usage.
 120 ///
 121 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 122 ///
 123 /// [module-level documentation]: self
 124 pub struct OfferBuilder<'a, M: MetadataStrategy, T: secp256k1::Signing> {
 125         offer: OfferContents,
 126         metadata_strategy: core::marker::PhantomData<M>,
 127         secp_ctx: Option<&'a Secp256k1<T>>,
 128 }
 129
 130 /// Builds an [`Offer`] for the "offer to be paid" flow.
 131 ///
 132 /// See [module-level documentation] for usage.
 133 ///
 134 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 135 ///
 136 /// [module-level documentation]: self
 137 #[cfg(c_bindings)]
 138 pub struct OfferWithExplicitMetadataBuilder<'a> {
 139         offer: OfferContents,
 140         metadata_strategy: core::marker::PhantomData<ExplicitMetadata>,
 141         secp_ctx: Option<&'a Secp256k1<secp256k1::All>>,
 142 }
 143
 144 /// Builds an [`Offer`] for the "offer to be paid" flow.
 145 ///
 146 /// See [module-level documentation] for usage.
 147 ///
 148 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 149 ///
 150 /// [module-level documentation]: self
 151 #[cfg(c_bindings)]
 152 pub struct OfferWithDerivedMetadataBuilder<'a> {
 153         offer: OfferContents,
 154         metadata_strategy: core::marker::PhantomData<DerivedMetadata>,
 155         secp_ctx: Option<&'a Secp256k1<secp256k1::All>>,
 156 }
 157
 158 /// Indicates how [`Offer::metadata`] may be set.
 159 ///
 160 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 161 pub trait MetadataStrategy {}
 162
 163 /// [`Offer::metadata`] may be explicitly set or left empty.
 164 ///
 165 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 166 pub struct ExplicitMetadata {}
 167
 168 /// [`Offer::metadata`] will be derived.
 169 ///
 170 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 171 pub struct DerivedMetadata {}
 172
 173 impl MetadataStrategy for ExplicitMetadata {}
 174
 175 impl MetadataStrategy for DerivedMetadata {}
 176
 177 macro_rules! offer_explicit_metadata_builder_methods { (
 178         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr
 179 ) => {
 180         /// Creates a new builder for an offer setting the [`Offer::description`] and using the
 181         /// [`Offer::signing_pubkey`] for signing invoices. The associated secret key must be remembered
 182         /// while the offer is valid.
 183         ///
 184         /// Use a different pubkey per offer to avoid correlating offers.
 185         ///
 186         /// # Note
 187         ///
 188         /// If constructing an [`Offer`] for use with a [`ChannelManager`], use
 189         /// [`ChannelManager::create_offer_builder`] instead of [`OfferBuilder::new`].
 190         ///
 191         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 192         /// [`ChannelManager::create_offer_builder`]: crate::ln::channelmanager::ChannelManager::create_offer_builder
 193         pub fn new(description: String, signing_pubkey: PublicKey) -> Self {
 194                 Self {
 195                         offer: OfferContents {
 196                                 chains: None, metadata: None, amount: None, description,
 197                                 features: OfferFeatures::empty(), absolute_expiry: None, issuer: None, paths: None,
 198                                 supported_quantity: Quantity::One, signing_pubkey,
 199                         },
 200                         metadata_strategy: core::marker::PhantomData,
 201                         secp_ctx: None,
 202                 }
 203         }
 204
 205         /// Sets the [`Offer::metadata`] to the given bytes.
 206         ///
 207         /// Successive calls to this method will override the previous setting.
 208         pub fn metadata(mut $self: $self_type, metadata: Vec<u8>) -> Result<$return_type, Bolt12SemanticError> {
 209                 $self.offer.metadata = Some(Metadata::Bytes(metadata));
 210                 Ok($return_value)
 211         }
 212 } }
 213
 214 macro_rules! offer_derived_metadata_builder_methods { ($secp_context: ty) => {
 215         /// Similar to [`OfferBuilder::new`] except, if [`OfferBuilder::path`] is called, the signing
 216         /// pubkey is derived from the given [`ExpandedKey`] and [`EntropySource`]. This provides
 217         /// recipient privacy by using a different signing pubkey for each offer. Otherwise, the
 218         /// provided `node_id` is used for the signing pubkey.
 219         ///
 220         /// Also, sets the metadata when [`OfferBuilder::build`] is called such that it can be used by
 221         /// [`InvoiceRequest::verify`] to determine if the request was produced for the offer given an
 222         /// [`ExpandedKey`].
 223         ///
 224         /// [`InvoiceRequest::verify`]: crate::offers::invoice_request::InvoiceRequest::verify
 225         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 226         pub fn deriving_signing_pubkey<ES: Deref>(
 227                 description: String, node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 228                 secp_ctx: &'a Secp256k1<$secp_context>
 229         ) -> Self where ES::Target: EntropySource {
 230                 let nonce = Nonce::from_entropy_source(entropy_source);
 231                 let derivation_material = MetadataMaterial::new(nonce, expanded_key, IV_BYTES, None);
 232                 let metadata = Metadata::DerivedSigningPubkey(derivation_material);
 233                 Self {
 234                         offer: OfferContents {
 235                                 chains: None, metadata: Some(metadata), amount: None, description,
 236                                 features: OfferFeatures::empty(), absolute_expiry: None, issuer: None, paths: None,
 237                                 supported_quantity: Quantity::One, signing_pubkey: node_id,
 238                         },
 239                         metadata_strategy: core::marker::PhantomData,
 240                         secp_ctx: Some(secp_ctx),
 241                 }
 242         }
 243 } }
 244
 245 macro_rules! offer_builder_methods { (
 246         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr $(, $self_mut: tt)?
 247 ) => {
 248         /// Adds the chain hash of the given [`Network`] to [`Offer::chains`]. If not called,
 249         /// the chain hash of [`Network::Bitcoin`] is assumed to be the only one supported.
 250         ///
 251         /// See [`Offer::chains`] on how this relates to the payment currency.
 252         ///
 253         /// Successive calls to this method will add another chain hash.
 254         pub fn chain($self: $self_type, network: Network) -> $return_type {
 255                 $self.chain_hash(ChainHash::using_genesis_block(network))
 256         }
 257
 258         /// Adds the [`ChainHash`] to [`Offer::chains`]. If not called, the chain hash of
 259         /// [`Network::Bitcoin`] is assumed to be the only one supported.
 260         ///
 261         /// See [`Offer::chains`] on how this relates to the payment currency.
 262         ///
 263         /// Successive calls to this method will add another chain hash.
 264         pub(crate) fn chain_hash($($self_mut)* $self: $self_type, chain: ChainHash) -> $return_type {
 265                 let chains = $self.offer.chains.get_or_insert_with(Vec::new);
 266                 if !chains.contains(&chain) {
 267                         chains.push(chain);
 268                 }
 269
 270                 $return_value
 271         }
 272
 273         /// Sets the [`Offer::amount`] as an [`Amount::Bitcoin`].
 274         ///
 275         /// Successive calls to this method will override the previous setting.
 276         pub fn amount_msats($self: $self_type, amount_msats: u64) -> $return_type {
 277                 $self.amount(Amount::Bitcoin { amount_msats })
 278         }
 279
 280         /// Sets the [`Offer::amount`].
 281         ///
 282         /// Successive calls to this method will override the previous setting.
 283         pub(super) fn amount($($self_mut)* $self: $self_type, amount: Amount) -> $return_type {
 284                 $self.offer.amount = Some(amount);
 285                 $return_value
 286         }
 287
 288         /// Sets the [`Offer::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
 289         /// already passed is valid and can be checked for using [`Offer::is_expired`].
 290         ///
 291         /// Successive calls to this method will override the previous setting.
 292         pub fn absolute_expiry($($self_mut)* $self: $self_type, absolute_expiry: Duration) -> $return_type {
 293                 $self.offer.absolute_expiry = Some(absolute_expiry);
 294                 $return_value
 295         }
 296
 297         /// Sets the [`Offer::issuer`].
 298         ///
 299         /// Successive calls to this method will override the previous setting.
 300         pub fn issuer($($self_mut)* $self: $self_type, issuer: String) -> $return_type {
 301                 $self.offer.issuer = Some(issuer);
 302                 $return_value
 303         }
 304
 305         /// Adds a blinded path to [`Offer::paths`]. Must include at least one path if only connected by
 306         /// private channels or if [`Offer::signing_pubkey`] is not a public node id.
 307         ///
 308         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 309         /// adding duplicate paths.
 310         pub fn path($($self_mut)* $self: $self_type, path: BlindedPath) -> $return_type {
 311                 $self.offer.paths.get_or_insert_with(Vec::new).push(path);
 312                 $return_value
 313         }
 314
 315         /// Sets the quantity of items for [`Offer::supported_quantity`]. If not called, defaults to
 316         /// [`Quantity::One`].
 317         ///
 318         /// Successive calls to this method will override the previous setting.
 319         pub fn supported_quantity($($self_mut)* $self: $self_type, quantity: Quantity) -> $return_type {
 320                 $self.offer.supported_quantity = quantity;
 321                 $return_value
 322         }
 323
 324         /// Builds an [`Offer`] from the builder's settings.
 325         pub fn build($($self_mut)* $self: $self_type) -> Result<Offer, Bolt12SemanticError> {
 326                 match $self.offer.amount {
 327                         Some(Amount::Bitcoin { amount_msats }) => {
 328                                 if amount_msats > MAX_VALUE_MSAT {
 329                                         return Err(Bolt12SemanticError::InvalidAmount);
 330                                 }
 331                         },
 332                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 333                         None => {},
 334                 }
 335
 336                 if let Some(chains) = &$self.offer.chains {
 337                         if chains.len() == 1 && chains[0] == $self.offer.implied_chain() {
 338                                 $self.offer.chains = None;
 339                         }
 340                 }
 341
 342                 Ok($self.build_without_checks())
 343         }
 344
 345         fn build_without_checks($($self_mut)* $self: $self_type) -> Offer {
 346                 // Create the metadata for stateless verification of an InvoiceRequest.
 347                 if let Some(mut metadata) = $self.offer.metadata.take() {
 348                         if metadata.has_derivation_material() {
 349                                 if $self.offer.paths.is_none() {
 350                                         metadata = metadata.without_keys();
 351                                 }
 352
 353                                 let mut tlv_stream = $self.offer.as_tlv_stream();
 354                                 debug_assert_eq!(tlv_stream.metadata, None);
 355                                 tlv_stream.metadata = None;
 356                                 if metadata.derives_recipient_keys() {
 357                                         tlv_stream.node_id = None;
 358                                 }
 359
 360                                 let (derived_metadata, keys) = metadata.derive_from(tlv_stream, $self.secp_ctx);
 361                                 metadata = derived_metadata;
 362                                 if let Some(keys) = keys {
 363                                         $self.offer.signing_pubkey = keys.public_key();
 364                                 }
 365                         }
 366
 367                         $self.offer.metadata = Some(metadata);
 368                 }
 369
 370                 let mut bytes = Vec::new();
 371                 $self.offer.write(&mut bytes).unwrap();
 372
 373                 Offer {
 374                         bytes,
 375                         #[cfg(not(c_bindings))]
 376                         contents: $self.offer,
 377                         #[cfg(c_bindings)]
 378                         contents: $self.offer.clone()
 379                 }
 380         }
 381 } }
 382
 383 #[cfg(test)]
 384 macro_rules! offer_builder_test_methods { (
 385         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr $(, $self_mut: tt)?
 386 ) => {
 387         #[cfg_attr(c_bindings, allow(dead_code))]
 388         fn features_unchecked($($self_mut)* $self: $self_type, features: OfferFeatures) -> $return_type {
 389                 $self.offer.features = features;
 390                 $return_value
 391         }
 392
 393         #[cfg_attr(c_bindings, allow(dead_code))]
 394         pub(crate) fn clear_chains($($self_mut)* $self: $self_type) -> $return_type {
 395                 $self.offer.chains = None;
 396                 $return_value
 397         }
 398
 399         #[cfg_attr(c_bindings, allow(dead_code))]
 400         pub(crate) fn clear_paths($($self_mut)* $self: $self_type) -> $return_type {
 401                 $self.offer.paths = None;
 402                 $return_value
 403         }
 404
 405         #[cfg_attr(c_bindings, allow(dead_code))]
 406         pub(super) fn build_unchecked($self: $self_type) -> Offer {
 407                 $self.build_without_checks()
 408         }
 409 } }
 410
 411 impl<'a, M: MetadataStrategy, T: secp256k1::Signing> OfferBuilder<'a, M, T> {
 412         offer_builder_methods!(self, Self, Self, self, mut);
 413
 414         #[cfg(test)]
 415         offer_builder_test_methods!(self, Self, Self, self, mut);
 416 }
 417
 418 impl<'a> OfferBuilder<'a, ExplicitMetadata, secp256k1::SignOnly> {
 419         offer_explicit_metadata_builder_methods!(self, Self, Self, self);
 420 }
 421
 422 impl<'a, T: secp256k1::Signing> OfferBuilder<'a, DerivedMetadata, T> {
 423         offer_derived_metadata_builder_methods!(T);
 424 }
 425
 426 #[cfg(all(c_bindings, not(test)))]
 427 impl<'a> OfferWithExplicitMetadataBuilder<'a> {
 428         offer_explicit_metadata_builder_methods!(self, &mut Self, (), ());
 429         offer_builder_methods!(self, &mut Self, (), ());
 430 }
 431
 432 #[cfg(all(c_bindings, test))]
 433 impl<'a> OfferWithExplicitMetadataBuilder<'a> {
 434         offer_explicit_metadata_builder_methods!(self, &mut Self, &mut Self, self);
 435         offer_builder_methods!(self, &mut Self, &mut Self, self);
 436         offer_builder_test_methods!(self, &mut Self, &mut Self, self);
 437 }
 438
 439 #[cfg(all(c_bindings, not(test)))]
 440 impl<'a> OfferWithDerivedMetadataBuilder<'a> {
 441         offer_derived_metadata_builder_methods!(secp256k1::All);
 442         offer_builder_methods!(self, &mut Self, (), ());
 443 }
 444
 445 #[cfg(all(c_bindings, test))]
 446 impl<'a> OfferWithDerivedMetadataBuilder<'a> {
 447         offer_derived_metadata_builder_methods!(secp256k1::All);
 448         offer_builder_methods!(self, &mut Self, &mut Self, self);
 449         offer_builder_test_methods!(self, &mut Self, &mut Self, self);
 450 }
 451
 452 #[cfg(c_bindings)]
 453 impl<'a> From<OfferBuilder<'a, DerivedMetadata, secp256k1::All>>
 454 for OfferWithDerivedMetadataBuilder<'a> {
 455         fn from(builder: OfferBuilder<'a, DerivedMetadata, secp256k1::All>) -> Self {
 456                 let OfferBuilder { offer, metadata_strategy, secp_ctx } = builder;
 457
 458                 Self { offer, metadata_strategy, secp_ctx }
 459         }
 460 }
 461
 462 /// An `Offer` is a potentially long-lived proposal for payment of a good or service.
 463 ///
 464 /// An offer is a precursor to an [`InvoiceRequest`]. A merchant publishes an offer from which a
 465 /// customer may request an [`Bolt12Invoice`] for a specific quantity and using an amount sufficient
 466 /// to cover that quantity (i.e., at least `quantity * amount`). See [`Offer::amount`].
 467 ///
 468 /// Offers may be denominated in currency other than bitcoin but are ultimately paid using the
 469 /// latter.
 470 ///
 471 /// Through the use of [`BlindedPath`]s, offers provide recipient privacy.
 472 ///
 473 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 474 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 475 #[derive(Clone, Debug)]
 476 pub struct Offer {
 477         // The serialized offer. Needed when creating an `InvoiceRequest` if the offer contains unknown
 478         // fields.
 479         pub(super) bytes: Vec<u8>,
 480         pub(super) contents: OfferContents,
 481 }
 482
 483 /// The contents of an [`Offer`], which may be shared with an [`InvoiceRequest`] or a
 484 /// [`Bolt12Invoice`].
 485 ///
 486 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 487 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 488 #[derive(Clone, Debug)]
 489 #[cfg_attr(test, derive(PartialEq))]
 490 pub(super) struct OfferContents {
 491         chains: Option<Vec<ChainHash>>,
 492         metadata: Option<Metadata>,
 493         amount: Option<Amount>,
 494         description: String,
 495         features: OfferFeatures,
 496         absolute_expiry: Option<Duration>,
 497         issuer: Option<String>,
 498         paths: Option<Vec<BlindedPath>>,
 499         supported_quantity: Quantity,
 500         signing_pubkey: PublicKey,
 501 }
 502
 503 macro_rules! offer_accessors { ($self: ident, $contents: expr) => {
 504         // TODO: Return a slice once ChainHash has constants.
 505         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1283
 506         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1286
 507         /// The chains that may be used when paying a requested invoice (e.g., bitcoin mainnet).
 508         /// Payments must be denominated in units of the minimal lightning-payable unit (e.g., msats)
 509         /// for the selected chain.
 510         pub fn chains(&$self) -> Vec<bitcoin::blockdata::constants::ChainHash> {
 511                 $contents.chains()
 512         }
 513
 514         // TODO: Link to corresponding method in `InvoiceRequest`.
 515         /// Opaque bytes set by the originator. Useful for authentication and validating fields since it
 516         /// is reflected in `invoice_request` messages along with all the other fields from the `offer`.
 517         pub fn metadata(&$self) -> Option<&Vec<u8>> {
 518                 $contents.metadata()
 519         }
 520
 521         /// The minimum amount required for a successful payment of a single item.
 522         pub fn amount(&$self) -> Option<&$crate::offers::offer::Amount> {
 523                 $contents.amount()
 524         }
 525
 526         /// A complete description of the purpose of the payment. Intended to be displayed to the user
 527         /// but with the caveat that it has not been verified in any way.
 528         pub fn description(&$self) -> $crate::util::string::PrintableString {
 529                 $contents.description()
 530         }
 531
 532         /// Features pertaining to the offer.
 533         pub fn offer_features(&$self) -> &$crate::ln::features::OfferFeatures {
 534                 &$contents.features()
 535         }
 536
 537         /// Duration since the Unix epoch when an invoice should no longer be requested.
 538         ///
 539         /// If `None`, the offer does not expire.
 540         pub fn absolute_expiry(&$self) -> Option<core::time::Duration> {
 541                 $contents.absolute_expiry()
 542         }
 543
 544         /// The issuer of the offer, possibly beginning with `user@domain` or `domain`. Intended to be
 545         /// displayed to the user but with the caveat that it has not been verified in any way.
 546         pub fn issuer(&$self) -> Option<$crate::util::string::PrintableString> {
 547                 $contents.issuer()
 548         }
 549
 550         /// Paths to the recipient originating from publicly reachable nodes. Blinded paths provide
 551         /// recipient privacy by obfuscating its node id.
 552         pub fn paths(&$self) -> &[$crate::blinded_path::BlindedPath] {
 553                 $contents.paths()
 554         }
 555
 556         /// The quantity of items supported.
 557         pub fn supported_quantity(&$self) -> $crate::offers::offer::Quantity {
 558                 $contents.supported_quantity()
 559         }
 560
 561         /// The public key used by the recipient to sign invoices.
 562         pub fn signing_pubkey(&$self) -> bitcoin::secp256k1::PublicKey {
 563                 $contents.signing_pubkey()
 564         }
 565 } }
 566
 567 impl Offer {
 568         offer_accessors!(self, self.contents);
 569
 570         pub(super) fn implied_chain(&self) -> ChainHash {
 571                 self.contents.implied_chain()
 572         }
 573
 574         /// Returns whether the given chain is supported by the offer.
 575         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 576                 self.contents.supports_chain(chain)
 577         }
 578
 579         /// Whether the offer has expired.
 580         #[cfg(feature = "std")]
 581         pub fn is_expired(&self) -> bool {
 582                 self.contents.is_expired()
 583         }
 584
 585         /// Whether the offer has expired given the duration since the Unix epoch.
 586         pub fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 587                 self.contents.is_expired_no_std(duration_since_epoch)
 588         }
 589
 590         /// Returns whether the given quantity is valid for the offer.
 591         pub fn is_valid_quantity(&self, quantity: u64) -> bool {
 592                 self.contents.is_valid_quantity(quantity)
 593         }
 594
 595         /// Returns whether a quantity is expected in an [`InvoiceRequest`] for the offer.
 596         ///
 597         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 598         pub fn expects_quantity(&self) -> bool {
 599                 self.contents.expects_quantity()
 600         }
 601 }
 602
 603 macro_rules! request_invoice_derived_payer_id { ($self: ident, $builder: ty) => {
 604         /// Similar to [`Offer::request_invoice`] except it:
 605         /// - derives the [`InvoiceRequest::payer_id`] such that a different key can be used for each
 606         ///   request,
 607         /// - sets [`InvoiceRequest::payer_metadata`] when [`InvoiceRequestBuilder::build`] is called
 608         ///   such that it can be used by [`Bolt12Invoice::verify`] to determine if the invoice was
 609         ///   requested using a base [`ExpandedKey`] from which the payer id was derived, and
 610         /// - includes the [`PaymentId`] encrypted in [`InvoiceRequest::payer_metadata`] so that it can
 611         ///   be used when sending the payment for the requested invoice.
 612         ///
 613         /// Useful to protect the sender's privacy.
 614         ///
 615         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 616         /// [`InvoiceRequest::payer_metadata`]: crate::offers::invoice_request::InvoiceRequest::payer_metadata
 617         /// [`Bolt12Invoice::verify`]: crate::offers::invoice::Bolt12Invoice::verify
 618         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 619         pub fn request_invoice_deriving_payer_id<
 620                 'a, 'b, ES: Deref,
 621                 #[cfg(not(c_bindings))]
 622                 T: secp256k1::Signing
 623         >(
 624                 &'a $self, expanded_key: &ExpandedKey, entropy_source: ES,
 625                 #[cfg(not(c_bindings))]
 626                 secp_ctx: &'b Secp256k1<T>,
 627                 #[cfg(c_bindings)]
 628                 secp_ctx: &'b Secp256k1<secp256k1::All>,
 629                 payment_id: PaymentId
 630         ) -> Result<$builder, Bolt12SemanticError>
 631         where
 632                 ES::Target: EntropySource,
 633         {
 634                 if $self.offer_features().requires_unknown_bits() {
 635                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 636                 }
 637
 638                 Ok(<$builder>::deriving_payer_id($self, expanded_key, entropy_source, secp_ctx, payment_id))
 639         }
 640 } }
 641
 642 macro_rules! request_invoice_explicit_payer_id { ($self: ident, $builder: ty) => {
 643         /// Similar to [`Offer::request_invoice_deriving_payer_id`] except uses `payer_id` for the
 644         /// [`InvoiceRequest::payer_id`] instead of deriving a different key for each request.
 645         ///
 646         /// Useful for recurring payments using the same `payer_id` with different invoices.
 647         ///
 648         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 649         pub fn request_invoice_deriving_metadata<ES: Deref>(
 650                 &$self, payer_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 651                 payment_id: PaymentId
 652         ) -> Result<$builder, Bolt12SemanticError>
 653         where
 654                 ES::Target: EntropySource,
 655         {
 656                 if $self.offer_features().requires_unknown_bits() {
 657                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 658                 }
 659
 660                 Ok(<$builder>::deriving_metadata($self, payer_id, expanded_key, entropy_source, payment_id))
 661         }
 662
 663         /// Creates an [`InvoiceRequestBuilder`] for the offer with the given `metadata` and `payer_id`,
 664         /// which will be reflected in the `Bolt12Invoice` response.
 665         ///
 666         /// The `metadata` is useful for including information about the derivation of `payer_id` such
 667         /// that invoice response handling can be stateless. Also serves as payer-provided entropy while
 668         /// hashing in the signature calculation.
 669         ///
 670         /// This should not leak any information such as by using a simple BIP-32 derivation path.
 671         /// Otherwise, payments may be correlated.
 672         ///
 673         /// Errors if the offer contains unknown required features.
 674         ///
 675         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 676         pub fn request_invoice(
 677                 &$self, metadata: Vec<u8>, payer_id: PublicKey
 678         ) -> Result<$builder, Bolt12SemanticError> {
 679                 if $self.offer_features().requires_unknown_bits() {
 680                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 681                 }
 682
 683                 Ok(<$builder>::new($self, metadata, payer_id))
 684         }
 685 } }
 686
 687 #[cfg(not(c_bindings))]
 688 impl Offer {
 689         request_invoice_derived_payer_id!(self, InvoiceRequestBuilder<'a, 'b, DerivedPayerId, T>);
 690         request_invoice_explicit_payer_id!(self, InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>);
 691 }
 692
 693 #[cfg(c_bindings)]
 694 impl Offer {
 695         request_invoice_derived_payer_id!(self, InvoiceRequestWithDerivedPayerIdBuilder<'a, 'b>);
 696         request_invoice_explicit_payer_id!(self, InvoiceRequestWithExplicitPayerIdBuilder);
 697 }
 698
 699 #[cfg(test)]
 700 impl Offer {
 701         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 702                 self.contents.as_tlv_stream()
 703         }
 704 }
 705
 706 impl AsRef<[u8]> for Offer {
 707         fn as_ref(&self) -> &[u8] {
 708                 &self.bytes
 709         }
 710 }
 711
 712 impl PartialEq for Offer {
 713         fn eq(&self, other: &Self) -> bool {
 714                 self.bytes.eq(&other.bytes)
 715         }
 716 }
 717
 718 impl Eq for Offer {}
 719
 720 impl Hash for Offer {
 721         fn hash<H: Hasher>(&self, state: &mut H) {
 722                 self.bytes.hash(state);
 723         }
 724 }
 725
 726 impl OfferContents {
 727         pub fn chains(&self) -> Vec<ChainHash> {
 728                 self.chains.as_ref().cloned().unwrap_or_else(|| vec![self.implied_chain()])
 729         }
 730
 731         pub fn implied_chain(&self) -> ChainHash {
 732                 ChainHash::using_genesis_block(Network::Bitcoin)
 733         }
 734
 735         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 736                 self.chains().contains(&chain)
 737         }
 738
 739         pub fn metadata(&self) -> Option<&Vec<u8>> {
 740                 self.metadata.as_ref().and_then(|metadata| metadata.as_bytes())
 741         }
 742
 743         pub fn amount(&self) -> Option<&Amount> {
 744                 self.amount.as_ref()
 745         }
 746
 747         pub fn description(&self) -> PrintableString {
 748                 PrintableString(&self.description)
 749         }
 750
 751         pub fn features(&self) -> &OfferFeatures {
 752                 &self.features
 753         }
 754
 755         pub fn absolute_expiry(&self) -> Option<Duration> {
 756                 self.absolute_expiry
 757         }
 758
 759         #[cfg(feature = "std")]
 760         pub(super) fn is_expired(&self) -> bool {
 761                 SystemTime::UNIX_EPOCH
 762                         .elapsed()
 763                         .map(|duration_since_epoch| self.is_expired_no_std(duration_since_epoch))
 764                         .unwrap_or(false)
 765         }
 766
 767         pub(super) fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 768                 self.absolute_expiry
 769                         .map(|absolute_expiry| duration_since_epoch > absolute_expiry)
 770                         .unwrap_or(false)
 771         }
 772
 773         pub fn issuer(&self) -> Option<PrintableString> {
 774                 self.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 775         }
 776
 777         pub fn paths(&self) -> &[BlindedPath] {
 778                 self.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 779         }
 780
 781         pub(super) fn check_amount_msats_for_quantity(
 782                 &self, amount_msats: Option<u64>, quantity: Option<u64>
 783         ) -> Result<(), Bolt12SemanticError> {
 784                 let offer_amount_msats = match self.amount {
 785                         None => 0,
 786                         Some(Amount::Bitcoin { amount_msats }) => amount_msats,
 787                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 788                 };
 789
 790                 if !self.expects_quantity() || quantity.is_some() {
 791                         let expected_amount_msats = offer_amount_msats.checked_mul(quantity.unwrap_or(1))
 792                                 .ok_or(Bolt12SemanticError::InvalidAmount)?;
 793                         let amount_msats = amount_msats.unwrap_or(expected_amount_msats);
 794
 795                         if amount_msats < expected_amount_msats {
 796                                 return Err(Bolt12SemanticError::InsufficientAmount);
 797                         }
 798
 799                         if amount_msats > MAX_VALUE_MSAT {
 800                                 return Err(Bolt12SemanticError::InvalidAmount);
 801                         }
 802                 }
 803
 804                 Ok(())
 805         }
 806
 807         pub fn supported_quantity(&self) -> Quantity {
 808                 self.supported_quantity
 809         }
 810
 811         pub(super) fn check_quantity(&self, quantity: Option<u64>) -> Result<(), Bolt12SemanticError> {
 812                 let expects_quantity = self.expects_quantity();
 813                 match quantity {
 814                         None if expects_quantity => Err(Bolt12SemanticError::MissingQuantity),
 815                         Some(_) if !expects_quantity => Err(Bolt12SemanticError::UnexpectedQuantity),
 816                         Some(quantity) if !self.is_valid_quantity(quantity) => {
 817                                 Err(Bolt12SemanticError::InvalidQuantity)
 818                         },
 819                         _ => Ok(()),
 820                 }
 821         }
 822
 823         fn is_valid_quantity(&self, quantity: u64) -> bool {
 824                 match self.supported_quantity {
 825                         Quantity::Bounded(n) => quantity <= n.get(),
 826                         Quantity::Unbounded => quantity > 0,
 827                         Quantity::One => quantity == 1,
 828                 }
 829         }
 830
 831         fn expects_quantity(&self) -> bool {
 832                 match self.supported_quantity {
 833                         Quantity::Bounded(_) => true,
 834                         Quantity::Unbounded => true,
 835                         Quantity::One => false,
 836                 }
 837         }
 838
 839         pub(super) fn signing_pubkey(&self) -> PublicKey {
 840                 self.signing_pubkey
 841         }
 842
 843         /// Verifies that the offer metadata was produced from the offer in the TLV stream.
 844         pub(super) fn verify<T: secp256k1::Signing>(
 845                 &self, bytes: &[u8], key: &ExpandedKey, secp_ctx: &Secp256k1<T>
 846         ) -> Result<Option<KeyPair>, ()> {
 847                 match self.metadata() {
 848                         Some(metadata) => {
 849                                 let tlv_stream = TlvStream::new(bytes).range(OFFER_TYPES).filter(|record| {
 850                                         match record.r#type {
 851                                                 OFFER_METADATA_TYPE => false,
 852                                                 OFFER_NODE_ID_TYPE => {
 853                                                         !self.metadata.as_ref().unwrap().derives_recipient_keys()
 854                                                 },
 855                                                 _ => true,
 856                                         }
 857                                 });
 858                                 signer::verify_recipient_metadata(
 859                                         metadata, key, IV_BYTES, self.signing_pubkey(), tlv_stream, secp_ctx
 860                                 )
 861                         },
 862                         None => Err(()),
 863                 }
 864         }
 865
 866         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 867                 let (currency, amount) = match &self.amount {
 868                         None => (None, None),
 869                         Some(Amount::Bitcoin { amount_msats }) => (None, Some(*amount_msats)),
 870                         Some(Amount::Currency { iso4217_code, amount }) => (
 871                                 Some(iso4217_code), Some(*amount)
 872                         ),
 873                 };
 874
 875                 let features = {
 876                         if self.features == OfferFeatures::empty() { None } else { Some(&self.features) }
 877                 };
 878
 879                 OfferTlvStreamRef {
 880                         chains: self.chains.as_ref(),
 881                         metadata: self.metadata(),
 882                         currency,
 883                         amount,
 884                         description: Some(&self.description),
 885                         features,
 886                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 887                         paths: self.paths.as_ref(),
 888                         issuer: self.issuer.as_ref(),
 889                         quantity_max: self.supported_quantity.to_tlv_record(),
 890                         node_id: Some(&self.signing_pubkey),
 891                 }
 892         }
 893 }
 894
 895 impl Writeable for Offer {
 896         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 897                 WithoutLength(&self.bytes).write(writer)
 898         }
 899 }
 900
 901 impl Writeable for OfferContents {
 902         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 903                 self.as_tlv_stream().write(writer)
 904         }
 905 }
 906
 907 /// The minimum amount required for an item in an [`Offer`], denominated in either bitcoin or
 908 /// another currency.
 909 #[derive(Clone, Debug, PartialEq)]
 910 pub enum Amount {
 911         /// An amount of bitcoin.
 912         Bitcoin {
 913                 /// The amount in millisatoshi.
 914                 amount_msats: u64,
 915         },
 916         /// An amount of currency specified using ISO 4712.
 917         Currency {
 918                 /// The currency that the amount is denominated in.
 919                 iso4217_code: CurrencyCode,
 920                 /// The amount in the currency unit adjusted by the ISO 4712 exponent (e.g., USD cents).
 921                 amount: u64,
 922         },
 923 }
 924
 925 /// An ISO 4712 three-letter currency code (e.g., USD).
 926 pub type CurrencyCode = [u8; 3];
 927
 928 /// Quantity of items supported by an [`Offer`].
 929 #[derive(Clone, Copy, Debug, PartialEq)]
 930 pub enum Quantity {
 931         /// Up to a specific number of items (inclusive). Use when more than one item can be requested
 932         /// but is limited (e.g., because of per customer or inventory limits).
 933         ///
 934         /// May be used with `NonZeroU64::new(1)` but prefer to use [`Quantity::One`] if only one item
 935         /// is supported.
 936         Bounded(NonZeroU64),
 937         /// One or more items. Use when more than one item can be requested without any limit.
 938         Unbounded,
 939         /// Only one item. Use when only a single item can be requested.
 940         One,
 941 }
 942
 943 impl Quantity {
 944         fn to_tlv_record(&self) -> Option<u64> {
 945                 match self {
 946                         Quantity::Bounded(n) => Some(n.get()),
 947                         Quantity::Unbounded => Some(0),
 948                         Quantity::One => None,
 949                 }
 950         }
 951 }
 952
 953 /// Valid type range for offer TLV records.
 954 pub(super) const OFFER_TYPES: core::ops::Range<u64> = 1..80;
 955
 956 /// TLV record type for [`Offer::metadata`].
 957 const OFFER_METADATA_TYPE: u64 = 4;
 958
 959 /// TLV record type for [`Offer::signing_pubkey`].
 960 const OFFER_NODE_ID_TYPE: u64 = 22;
 961
 962 tlv_stream!(OfferTlvStream, OfferTlvStreamRef, OFFER_TYPES, {
 963         (2, chains: (Vec<ChainHash>, WithoutLength)),
 964         (OFFER_METADATA_TYPE, metadata: (Vec<u8>, WithoutLength)),
 965         (6, currency: CurrencyCode),
 966         (8, amount: (u64, HighZeroBytesDroppedBigSize)),
 967         (10, description: (String, WithoutLength)),
 968         (12, features: (OfferFeatures, WithoutLength)),
 969         (14, absolute_expiry: (u64, HighZeroBytesDroppedBigSize)),
 970         (16, paths: (Vec<BlindedPath>, WithoutLength)),
 971         (18, issuer: (String, WithoutLength)),
 972         (20, quantity_max: (u64, HighZeroBytesDroppedBigSize)),
 973         (OFFER_NODE_ID_TYPE, node_id: PublicKey),
 974 });
 975
 976 impl Bech32Encode for Offer {
 977         const BECH32_HRP: &'static str = "lno";
 978 }
 979
 980 impl FromStr for Offer {
 981         type Err = Bolt12ParseError;
 982
 983         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 984                 Self::from_bech32_str(s)
 985         }
 986 }
 987
 988 impl TryFrom<Vec<u8>> for Offer {
 989         type Error = Bolt12ParseError;
 990
 991         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 992                 let offer = ParsedMessage::<OfferTlvStream>::try_from(bytes)?;
 993                 let ParsedMessage { bytes, tlv_stream } = offer;
 994                 let contents = OfferContents::try_from(tlv_stream)?;
 995                 Ok(Offer { bytes, contents })
 996         }
 997 }
 998
 999 impl TryFrom<OfferTlvStream> for OfferContents {
1000         type Error = Bolt12SemanticError;
1001
1002         fn try_from(tlv_stream: OfferTlvStream) -> Result<Self, Self::Error> {
1003                 let OfferTlvStream {
1004                         chains, metadata, currency, amount, description, features, absolute_expiry, paths,
1005                         issuer, quantity_max, node_id,
1006                 } = tlv_stream;
1007
1008                 let metadata = metadata.map(|metadata| Metadata::Bytes(metadata));
1009
1010                 let amount = match (currency, amount) {
1011                         (None, None) => None,
1012                         (None, Some(amount_msats)) if amount_msats > MAX_VALUE_MSAT => {
1013                                 return Err(Bolt12SemanticError::InvalidAmount);
1014                         },
1015                         (None, Some(amount_msats)) => Some(Amount::Bitcoin { amount_msats }),
1016                         (Some(_), None) => return Err(Bolt12SemanticError::MissingAmount),
1017                         (Some(iso4217_code), Some(amount)) => Some(Amount::Currency { iso4217_code, amount }),
1018                 };
1019
1020                 let description = match description {
1021                         None => return Err(Bolt12SemanticError::MissingDescription),
1022                         Some(description) => description,
1023                 };
1024
1025                 let features = features.unwrap_or_else(OfferFeatures::empty);
1026
1027                 let absolute_expiry = absolute_expiry
1028                         .map(|seconds_from_epoch| Duration::from_secs(seconds_from_epoch));
1029
1030                 let supported_quantity = match quantity_max {
1031                         None => Quantity::One,
1032                         Some(0) => Quantity::Unbounded,
1033                         Some(n) => Quantity::Bounded(NonZeroU64::new(n).unwrap()),
1034                 };
1035
1036                 let signing_pubkey = match node_id {
1037                         None => return Err(Bolt12SemanticError::MissingSigningPubkey),
1038                         Some(node_id) => node_id,
1039                 };
1040
1041                 Ok(OfferContents {
1042                         chains, metadata, amount, description, features, absolute_expiry, issuer, paths,
1043                         supported_quantity, signing_pubkey,
1044                 })
1045         }
1046 }
1047
1048 impl core::fmt::Display for Offer {
1049         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
1050                 self.fmt_bech32_str(f)
1051         }
1052 }
1053
1054 #[cfg(test)]
1055 mod tests {
1056         use super::{Amount, Offer, OfferTlvStreamRef, Quantity};
1057         #[cfg(not(c_bindings))]
1058         use {
1059                 super::OfferBuilder,
1060         };
1061         #[cfg(c_bindings)]
1062         use {
1063                 super::OfferWithExplicitMetadataBuilder as OfferBuilder,
1064         };
1065
1066         use bitcoin::blockdata::constants::ChainHash;
1067         use bitcoin::network::constants::Network;
1068         use bitcoin::secp256k1::Secp256k1;
1069         use core::num::NonZeroU64;
1070         use core::time::Duration;
1071         use crate::blinded_path::{BlindedHop, BlindedPath};
1072         use crate::sign::KeyMaterial;
1073         use crate::ln::features::OfferFeatures;
1074         use crate::ln::inbound_payment::ExpandedKey;
1075         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
1076         use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
1077         use crate::offers::test_utils::*;
1078         use crate::util::ser::{BigSize, Writeable};
1079         use crate::util::string::PrintableString;
1080
1081         #[test]
1082         fn builds_offer_with_defaults() {
1083                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1084
1085                 let mut buffer = Vec::new();
1086                 offer.write(&mut buffer).unwrap();
1087
1088                 assert_eq!(offer.bytes, buffer.as_slice());
1089                 assert_eq!(offer.chains(), vec![ChainHash::using_genesis_block(Network::Bitcoin)]);
1090                 assert!(offer.supports_chain(ChainHash::using_genesis_block(Network::Bitcoin)));
1091                 assert_eq!(offer.metadata(), None);
1092                 assert_eq!(offer.amount(), None);
1093                 assert_eq!(offer.description(), PrintableString("foo"));
1094                 assert_eq!(offer.offer_features(), &OfferFeatures::empty());
1095                 assert_eq!(offer.absolute_expiry(), None);
1096                 #[cfg(feature = "std")]
1097                 assert!(!offer.is_expired());
1098                 assert_eq!(offer.paths(), &[]);
1099                 assert_eq!(offer.issuer(), None);
1100                 assert_eq!(offer.supported_quantity(), Quantity::One);
1101                 assert_eq!(offer.signing_pubkey(), pubkey(42));
1102
1103                 assert_eq!(
1104                         offer.as_tlv_stream(),
1105                         OfferTlvStreamRef {
1106                                 chains: None,
1107                                 metadata: None,
1108                                 currency: None,
1109                                 amount: None,
1110                                 description: Some(&String::from("foo")),
1111                                 features: None,
1112                                 absolute_expiry: None,
1113                                 paths: None,
1114                                 issuer: None,
1115                                 quantity_max: None,
1116                                 node_id: Some(&pubkey(42)),
1117                         },
1118                 );
1119
1120                 if let Err(e) = Offer::try_from(buffer) {
1121                         panic!("error parsing offer: {:?}", e);
1122                 }
1123         }
1124
1125         #[test]
1126         fn builds_offer_with_chains() {
1127                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
1128                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
1129
1130                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1131                         .chain(Network::Bitcoin)
1132                         .build()
1133                         .unwrap();
1134                 assert!(offer.supports_chain(mainnet));
1135                 assert_eq!(offer.chains(), vec![mainnet]);
1136                 assert_eq!(offer.as_tlv_stream().chains, None);
1137
1138                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1139                         .chain(Network::Testnet)
1140                         .build()
1141                         .unwrap();
1142                 assert!(offer.supports_chain(testnet));
1143                 assert_eq!(offer.chains(), vec![testnet]);
1144                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
1145
1146                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1147                         .chain(Network::Testnet)
1148                         .chain(Network::Testnet)
1149                         .build()
1150                         .unwrap();
1151                 assert!(offer.supports_chain(testnet));
1152                 assert_eq!(offer.chains(), vec![testnet]);
1153                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
1154
1155                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1156                         .chain(Network::Bitcoin)
1157                         .chain(Network::Testnet)
1158                         .build()
1159                         .unwrap();
1160                 assert!(offer.supports_chain(mainnet));
1161                 assert!(offer.supports_chain(testnet));
1162                 assert_eq!(offer.chains(), vec![mainnet, testnet]);
1163                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![mainnet, testnet]));
1164         }
1165
1166         #[test]
1167         fn builds_offer_with_metadata() {
1168                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1169                         .metadata(vec![42; 32]).unwrap()
1170                         .build()
1171                         .unwrap();
1172                 assert_eq!(offer.metadata(), Some(&vec![42; 32]));
1173                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![42; 32]));
1174
1175                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1176                         .metadata(vec![42; 32]).unwrap()
1177                         .metadata(vec![43; 32]).unwrap()
1178                         .build()
1179                         .unwrap();
1180                 assert_eq!(offer.metadata(), Some(&vec![43; 32]));
1181                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![43; 32]));
1182         }
1183
1184         #[test]
1185         fn builds_offer_with_metadata_derived() {
1186                 let desc = "foo".to_string();
1187                 let node_id = recipient_pubkey();
1188                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1189                 let entropy = FixedEntropy {};
1190                 let secp_ctx = Secp256k1::new();
1191
1192                 #[cfg(c_bindings)]
1193                 use super::OfferWithDerivedMetadataBuilder as OfferBuilder;
1194                 let offer = OfferBuilder
1195                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
1196                         .amount_msats(1000)
1197                         .build().unwrap();
1198                 assert_eq!(offer.signing_pubkey(), node_id);
1199
1200                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1201                         .build().unwrap()
1202                         .sign(payer_sign).unwrap();
1203                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
1204
1205                 // Fails verification with altered offer field
1206                 let mut tlv_stream = offer.as_tlv_stream();
1207                 tlv_stream.amount = Some(100);
1208
1209                 let mut encoded_offer = Vec::new();
1210                 tlv_stream.write(&mut encoded_offer).unwrap();
1211
1212                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1213                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1214                         .build().unwrap()
1215                         .sign(payer_sign).unwrap();
1216                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1217
1218                 // Fails verification with altered metadata
1219                 let mut tlv_stream = offer.as_tlv_stream();
1220                 let metadata = tlv_stream.metadata.unwrap().iter().copied().rev().collect();
1221                 tlv_stream.metadata = Some(&metadata);
1222
1223                 let mut encoded_offer = Vec::new();
1224                 tlv_stream.write(&mut encoded_offer).unwrap();
1225
1226                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1227                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1228                         .build().unwrap()
1229                         .sign(payer_sign).unwrap();
1230                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1231         }
1232
1233         #[test]
1234         fn builds_offer_with_derived_signing_pubkey() {
1235                 let desc = "foo".to_string();
1236                 let node_id = recipient_pubkey();
1237                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1238                 let entropy = FixedEntropy {};
1239                 let secp_ctx = Secp256k1::new();
1240
1241                 let blinded_path = BlindedPath {
1242                         introduction_node_id: pubkey(40),
1243                         blinding_point: pubkey(41),
1244                         blinded_hops: vec![
1245                                 BlindedHop { blinded_node_id: pubkey(42), encrypted_payload: vec![0; 43] },
1246                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
1247                         ],
1248                 };
1249
1250                 #[cfg(c_bindings)]
1251                 use super::OfferWithDerivedMetadataBuilder as OfferBuilder;
1252                 let offer = OfferBuilder
1253                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
1254                         .amount_msats(1000)
1255                         .path(blinded_path)
1256                         .build().unwrap();
1257                 assert_ne!(offer.signing_pubkey(), node_id);
1258
1259                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1260                         .build().unwrap()
1261                         .sign(payer_sign).unwrap();
1262                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_ok());
1263
1264                 // Fails verification with altered offer field
1265                 let mut tlv_stream = offer.as_tlv_stream();
1266                 tlv_stream.amount = Some(100);
1267
1268                 let mut encoded_offer = Vec::new();
1269                 tlv_stream.write(&mut encoded_offer).unwrap();
1270
1271                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1272                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1273                         .build().unwrap()
1274                         .sign(payer_sign).unwrap();
1275                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1276
1277                 // Fails verification with altered signing pubkey
1278                 let mut tlv_stream = offer.as_tlv_stream();
1279                 let signing_pubkey = pubkey(1);
1280                 tlv_stream.node_id = Some(&signing_pubkey);
1281
1282                 let mut encoded_offer = Vec::new();
1283                 tlv_stream.write(&mut encoded_offer).unwrap();
1284
1285                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1286                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1287                         .build().unwrap()
1288                         .sign(payer_sign).unwrap();
1289                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1290         }
1291
1292         #[test]
1293         fn builds_offer_with_amount() {
1294                 let bitcoin_amount = Amount::Bitcoin { amount_msats: 1000 };
1295                 let currency_amount = Amount::Currency { iso4217_code: *b"USD", amount: 10 };
1296
1297                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1298                         .amount_msats(1000)
1299                         .build()
1300                         .unwrap();
1301                 let tlv_stream = offer.as_tlv_stream();
1302                 assert_eq!(offer.amount(), Some(&bitcoin_amount));
1303                 assert_eq!(tlv_stream.amount, Some(1000));
1304                 assert_eq!(tlv_stream.currency, None);
1305
1306                 #[cfg(not(c_bindings))]
1307                 let builder = OfferBuilder::new("foo".into(), pubkey(42))
1308                         .amount(currency_amount.clone());
1309                 #[cfg(c_bindings)]
1310                 let mut builder = OfferBuilder::new("foo".into(), pubkey(42));
1311                 #[cfg(c_bindings)]
1312                 builder.amount(currency_amount.clone());
1313                 let tlv_stream = builder.offer.as_tlv_stream();
1314                 assert_eq!(builder.offer.amount, Some(currency_amount.clone()));
1315                 assert_eq!(tlv_stream.amount, Some(10));
1316                 assert_eq!(tlv_stream.currency, Some(b"USD"));
1317                 match builder.build() {
1318                         Ok(_) => panic!("expected error"),
1319                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnsupportedCurrency),
1320                 }
1321
1322                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1323                         .amount(currency_amount.clone())
1324                         .amount(bitcoin_amount.clone())
1325                         .build()
1326                         .unwrap();
1327                 let tlv_stream = offer.as_tlv_stream();
1328                 assert_eq!(tlv_stream.amount, Some(1000));
1329                 assert_eq!(tlv_stream.currency, None);
1330
1331                 let invalid_amount = Amount::Bitcoin { amount_msats: MAX_VALUE_MSAT + 1 };
1332                 match OfferBuilder::new("foo".into(), pubkey(42)).amount(invalid_amount).build() {
1333                         Ok(_) => panic!("expected error"),
1334                         Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
1335                 }
1336         }
1337
1338         #[test]
1339         fn builds_offer_with_features() {
1340                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1341                         .features_unchecked(OfferFeatures::unknown())
1342                         .build()
1343                         .unwrap();
1344                 assert_eq!(offer.offer_features(), &OfferFeatures::unknown());
1345                 assert_eq!(offer.as_tlv_stream().features, Some(&OfferFeatures::unknown()));
1346
1347                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1348                         .features_unchecked(OfferFeatures::unknown())
1349                         .features_unchecked(OfferFeatures::empty())
1350                         .build()
1351                         .unwrap();
1352                 assert_eq!(offer.offer_features(), &OfferFeatures::empty());
1353                 assert_eq!(offer.as_tlv_stream().features, None);
1354         }
1355
1356         #[test]
1357         fn builds_offer_with_absolute_expiry() {
1358                 let future_expiry = Duration::from_secs(u64::max_value());
1359                 let past_expiry = Duration::from_secs(0);
1360                 let now = future_expiry - Duration::from_secs(1_000);
1361
1362                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1363                         .absolute_expiry(future_expiry)
1364                         .build()
1365                         .unwrap();
1366                 #[cfg(feature = "std")]
1367                 assert!(!offer.is_expired());
1368                 assert!(!offer.is_expired_no_std(now));
1369                 assert_eq!(offer.absolute_expiry(), Some(future_expiry));
1370                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(future_expiry.as_secs()));
1371
1372                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1373                         .absolute_expiry(future_expiry)
1374                         .absolute_expiry(past_expiry)
1375                         .build()
1376                         .unwrap();
1377                 #[cfg(feature = "std")]
1378                 assert!(offer.is_expired());
1379                 assert!(offer.is_expired_no_std(now));
1380                 assert_eq!(offer.absolute_expiry(), Some(past_expiry));
1381                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(past_expiry.as_secs()));
1382         }
1383
1384         #[test]
1385         fn builds_offer_with_paths() {
1386                 let paths = vec![
1387                         BlindedPath {
1388                                 introduction_node_id: pubkey(40),
1389                                 blinding_point: pubkey(41),
1390                                 blinded_hops: vec![
1391                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1392                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1393                                 ],
1394                         },
1395                         BlindedPath {
1396                                 introduction_node_id: pubkey(40),
1397                                 blinding_point: pubkey(41),
1398                                 blinded_hops: vec![
1399                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1400                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1401                                 ],
1402                         },
1403                 ];
1404
1405                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1406                         .path(paths[0].clone())
1407                         .path(paths[1].clone())
1408                         .build()
1409                         .unwrap();
1410                 let tlv_stream = offer.as_tlv_stream();
1411                 assert_eq!(offer.paths(), paths.as_slice());
1412                 assert_eq!(offer.signing_pubkey(), pubkey(42));
1413                 assert_ne!(pubkey(42), pubkey(44));
1414                 assert_eq!(tlv_stream.paths, Some(&paths));
1415                 assert_eq!(tlv_stream.node_id, Some(&pubkey(42)));
1416         }
1417
1418         #[test]
1419         fn builds_offer_with_issuer() {
1420                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1421                         .issuer("bar".into())
1422                         .build()
1423                         .unwrap();
1424                 assert_eq!(offer.issuer(), Some(PrintableString("bar")));
1425                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("bar")));
1426
1427                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1428                         .issuer("bar".into())
1429                         .issuer("baz".into())
1430                         .build()
1431                         .unwrap();
1432                 assert_eq!(offer.issuer(), Some(PrintableString("baz")));
1433                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("baz")));
1434         }
1435
1436         #[test]
1437         fn builds_offer_with_supported_quantity() {
1438                 let one = NonZeroU64::new(1).unwrap();
1439                 let ten = NonZeroU64::new(10).unwrap();
1440
1441                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1442                         .supported_quantity(Quantity::One)
1443                         .build()
1444                         .unwrap();
1445                 let tlv_stream = offer.as_tlv_stream();
1446                 assert_eq!(offer.supported_quantity(), Quantity::One);
1447                 assert_eq!(tlv_stream.quantity_max, None);
1448
1449                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1450                         .supported_quantity(Quantity::Unbounded)
1451                         .build()
1452                         .unwrap();
1453                 let tlv_stream = offer.as_tlv_stream();
1454                 assert_eq!(offer.supported_quantity(), Quantity::Unbounded);
1455                 assert_eq!(tlv_stream.quantity_max, Some(0));
1456
1457                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1458                         .supported_quantity(Quantity::Bounded(ten))
1459                         .build()
1460                         .unwrap();
1461                 let tlv_stream = offer.as_tlv_stream();
1462                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(ten));
1463                 assert_eq!(tlv_stream.quantity_max, Some(10));
1464
1465                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1466                         .supported_quantity(Quantity::Bounded(one))
1467                         .build()
1468                         .unwrap();
1469                 let tlv_stream = offer.as_tlv_stream();
1470                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(one));
1471                 assert_eq!(tlv_stream.quantity_max, Some(1));
1472
1473                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1474                         .supported_quantity(Quantity::Bounded(ten))
1475                         .supported_quantity(Quantity::One)
1476                         .build()
1477                         .unwrap();
1478                 let tlv_stream = offer.as_tlv_stream();
1479                 assert_eq!(offer.supported_quantity(), Quantity::One);
1480                 assert_eq!(tlv_stream.quantity_max, None);
1481         }
1482
1483         #[test]
1484         fn fails_requesting_invoice_with_unknown_required_features() {
1485                 match OfferBuilder::new("foo".into(), pubkey(42))
1486                         .features_unchecked(OfferFeatures::unknown())
1487                         .build().unwrap()
1488                         .request_invoice(vec![1; 32], pubkey(43))
1489                 {
1490                         Ok(_) => panic!("expected error"),
1491                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnknownRequiredFeatures),
1492                 }
1493         }
1494
1495         #[test]
1496         fn parses_offer_with_chains() {
1497                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1498                         .chain(Network::Bitcoin)
1499                         .chain(Network::Testnet)
1500                         .build()
1501                         .unwrap();
1502                 if let Err(e) = offer.to_string().parse::<Offer>() {
1503                         panic!("error parsing offer: {:?}", e);
1504                 }
1505         }
1506
1507         #[test]
1508         fn parses_offer_with_amount() {
1509                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1510                         .amount(Amount::Bitcoin { amount_msats: 1000 })
1511                         .build()
1512                         .unwrap();
1513                 if let Err(e) = offer.to_string().parse::<Offer>() {
1514                         panic!("error parsing offer: {:?}", e);
1515                 }
1516
1517                 let mut tlv_stream = offer.as_tlv_stream();
1518                 tlv_stream.amount = Some(1000);
1519                 tlv_stream.currency = Some(b"USD");
1520
1521                 let mut encoded_offer = Vec::new();
1522                 tlv_stream.write(&mut encoded_offer).unwrap();
1523
1524                 if let Err(e) = Offer::try_from(encoded_offer) {
1525                         panic!("error parsing offer: {:?}", e);
1526                 }
1527
1528                 let mut tlv_stream = offer.as_tlv_stream();
1529                 tlv_stream.amount = None;
1530                 tlv_stream.currency = Some(b"USD");
1531
1532                 let mut encoded_offer = Vec::new();
1533                 tlv_stream.write(&mut encoded_offer).unwrap();
1534
1535                 match Offer::try_from(encoded_offer) {
1536                         Ok(_) => panic!("expected error"),
1537                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingAmount)),
1538                 }
1539
1540                 let mut tlv_stream = offer.as_tlv_stream();
1541                 tlv_stream.amount = Some(MAX_VALUE_MSAT + 1);
1542                 tlv_stream.currency = None;
1543
1544                 let mut encoded_offer = Vec::new();
1545                 tlv_stream.write(&mut encoded_offer).unwrap();
1546
1547                 match Offer::try_from(encoded_offer) {
1548                         Ok(_) => panic!("expected error"),
1549                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InvalidAmount)),
1550                 }
1551         }
1552
1553         #[test]
1554         fn parses_offer_with_description() {
1555                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1556                 if let Err(e) = offer.to_string().parse::<Offer>() {
1557                         panic!("error parsing offer: {:?}", e);
1558                 }
1559
1560                 let mut tlv_stream = offer.as_tlv_stream();
1561                 tlv_stream.description = None;
1562
1563                 let mut encoded_offer = Vec::new();
1564                 tlv_stream.write(&mut encoded_offer).unwrap();
1565
1566                 match Offer::try_from(encoded_offer) {
1567                         Ok(_) => panic!("expected error"),
1568                         Err(e) => {
1569                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription));
1570                         },
1571                 }
1572         }
1573
1574         #[test]
1575         fn parses_offer_with_paths() {
1576                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1577                         .path(BlindedPath {
1578                                 introduction_node_id: pubkey(40),
1579                                 blinding_point: pubkey(41),
1580                                 blinded_hops: vec![
1581                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1582                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1583                                 ],
1584                         })
1585                         .path(BlindedPath {
1586                                 introduction_node_id: pubkey(40),
1587                                 blinding_point: pubkey(41),
1588                                 blinded_hops: vec![
1589                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1590                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1591                                 ],
1592                         })
1593                         .build()
1594                         .unwrap();
1595                 if let Err(e) = offer.to_string().parse::<Offer>() {
1596                         panic!("error parsing offer: {:?}", e);
1597                 }
1598
1599                 let mut builder = OfferBuilder::new("foo".into(), pubkey(42));
1600                 builder.offer.paths = Some(vec![]);
1601
1602                 let offer = builder.build().unwrap();
1603                 if let Err(e) = offer.to_string().parse::<Offer>() {
1604                         panic!("error parsing offer: {:?}", e);
1605                 }
1606         }
1607
1608         #[test]
1609         fn parses_offer_with_quantity() {
1610                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1611                         .supported_quantity(Quantity::One)
1612                         .build()
1613                         .unwrap();
1614                 if let Err(e) = offer.to_string().parse::<Offer>() {
1615                         panic!("error parsing offer: {:?}", e);
1616                 }
1617
1618                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1619                         .supported_quantity(Quantity::Unbounded)
1620                         .build()
1621                         .unwrap();
1622                 if let Err(e) = offer.to_string().parse::<Offer>() {
1623                         panic!("error parsing offer: {:?}", e);
1624                 }
1625
1626                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1627                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(10).unwrap()))
1628                         .build()
1629                         .unwrap();
1630                 if let Err(e) = offer.to_string().parse::<Offer>() {
1631                         panic!("error parsing offer: {:?}", e);
1632                 }
1633
1634                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1635                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(1).unwrap()))
1636                         .build()
1637                         .unwrap();
1638                 if let Err(e) = offer.to_string().parse::<Offer>() {
1639                         panic!("error parsing offer: {:?}", e);
1640                 }
1641         }
1642
1643         #[test]
1644         fn parses_offer_with_node_id() {
1645                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1646                 if let Err(e) = offer.to_string().parse::<Offer>() {
1647                         panic!("error parsing offer: {:?}", e);
1648                 }
1649
1650                 let mut tlv_stream = offer.as_tlv_stream();
1651                 tlv_stream.node_id = None;
1652
1653                 let mut encoded_offer = Vec::new();
1654                 tlv_stream.write(&mut encoded_offer).unwrap();
1655
1656                 match Offer::try_from(encoded_offer) {
1657                         Ok(_) => panic!("expected error"),
1658                         Err(e) => {
1659                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingSigningPubkey));
1660                         },
1661                 }
1662         }
1663
1664         #[test]
1665         fn fails_parsing_offer_with_extra_tlv_records() {
1666                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1667
1668                 let mut encoded_offer = Vec::new();
1669                 offer.write(&mut encoded_offer).unwrap();
1670                 BigSize(80).write(&mut encoded_offer).unwrap();
1671                 BigSize(32).write(&mut encoded_offer).unwrap();
1672                 [42u8; 32].write(&mut encoded_offer).unwrap();
1673
1674                 match Offer::try_from(encoded_offer) {
1675                         Ok(_) => panic!("expected error"),
1676                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1677                 }
1678         }
1679 }
1680
1681 #[cfg(test)]
1682 mod bolt12_tests {
1683         use super::{Bolt12ParseError, Bolt12SemanticError, Offer};
1684         use crate::ln::msgs::DecodeError;
1685
1686         #[test]
1687         fn parses_bech32_encoded_offers() {
1688                 let offers = [
1689                         // Minimal bolt12 offer
1690                         "lno1pgx9getnwss8vetrw3hhyuckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1691
1692                         // for testnet
1693                         "lno1qgsyxjtl6luzd9t3pr62xr7eemp6awnejusgf6gw45q75vcfqqqqqqq2p32x2um5ypmx2cm5dae8x93pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpj",
1694
1695                         // for bitcoin (redundant)
1696                         "lno1qgsxlc5vp2m0rvmjcxn2y34wv0m5lyc7sdj7zksgn35dvxgqqqqqqqq2p32x2um5ypmx2cm5dae8x93pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpj",
1697
1698                         // for bitcoin or liquidv1
1699                         "lno1qfqpge38tqmzyrdjj3x2qkdr5y80dlfw56ztq6yd9sme995g3gsxqqm0u2xq4dh3kdevrf4zg6hx8a60jv0gxe0ptgyfc6xkryqqqqqqqq9qc4r9wd6zqan9vd6x7unnzcss9mk8y3wkklfvevcrszlmu23kfrxh49px20665dqwmn4p72pksese",
1700
1701                         // with metadata
1702                         "lno1qsgqqqqqqqqqqqqqqqqqqqqqqqqqqzsv23jhxapqwejkxar0wfe3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1703
1704                         // with amount
1705                         "lno1pqpzwyq2p32x2um5ypmx2cm5dae8x93pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpj",
1706
1707                         // with currency
1708                         "lno1qcp4256ypqpzwyq2p32x2um5ypmx2cm5dae8x93pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpj",
1709
1710                         // with expiry
1711                         "lno1pgx9getnwss8vetrw3hhyucwq3ay997czcss9mk8y3wkklfvevcrszlmu23kfrxh49px20665dqwmn4p72pksese",
1712
1713                         // with issuer
1714                         "lno1pgx9getnwss8vetrw3hhyucjy358garswvaz7tmzdak8gvfj9ehhyeeqgf85c4p3xgsxjmnyw4ehgunfv4e3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1715
1716                         // with quantity
1717                         "lno1pgx9getnwss8vetrw3hhyuc5qyz3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1718
1719                         // with unlimited (or unknown) quantity
1720                         "lno1pgx9getnwss8vetrw3hhyuc5qqtzzqhwcuj966ma9n9nqwqtl032xeyv6755yeflt235pmww58egx6rxry",
1721
1722                         // with single quantity (weird but valid)
1723                         "lno1pgx9getnwss8vetrw3hhyuc5qyq3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1724
1725                         // with feature
1726                         "lno1pgx9getnwss8vetrw3hhyucvp5yqqqqqqqqqqqqqqqqqqqqkyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1727
1728                         // with blinded path via Bob (0x424242...), blinding 020202...
1729                         "lno1pgx9getnwss8vetrw3hhyucs5ypjgef743p5fzqq9nqxh0ah7y87rzv3ud0eleps9kl2d5348hq2k8qzqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgqpqqqqqqqqqqqqqqqqqqqqqqqqqqqzqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqqzq3zyg3zyg3zyg3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1730
1731                         // ... and with second blinded path via Carol (0x434343...), blinding 020202...
1732                         "lno1pgx9getnwss8vetrw3hhyucsl5q5yqeyv5l2cs6y3qqzesrth7mlzrlp3xg7xhulusczm04x6g6nms9trspqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqqsqqqqqqqqqqqqqqqqqqqqqqqqqqpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsqpqg3zyg3zyg3zygz0uc7h32x9s0aecdhxlk075kn046aafpuuyw8f5j652t3vha2yqrsyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsqzqqqqqqqqqqqqqqqqqqqqqqqqqqqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqqyzyg3zyg3zyg3zzcss9mk8y3wkklfvevcrszlmu23kfrxh49px20665dqwmn4p72pksese",
1733
1734                         // unknown odd field
1735                         "lno1pgx9getnwss8vetrw3hhyuckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxfppf5x2mrvdamk7unvvs",
1736                 ];
1737                 for encoded_offer in &offers {
1738                         if let Err(e) = encoded_offer.parse::<Offer>() {
1739                                 panic!("Invalid offer ({:?}): {}", e, encoded_offer);
1740                         }
1741                 }
1742         }
1743
1744         #[test]
1745         fn fails_parsing_bech32_encoded_offers() {
1746                 // Malformed: fields out of order
1747                 assert_eq!(
1748                         "lno1zcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszpgz5znzfgdzs".parse::<Offer>(),
1749                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1750                 );
1751
1752                 // Malformed: unknown even TLV type 78
1753                 assert_eq!(
1754                         "lno1pgz5znzfgdz3vggzqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpysgr0u2xq4dh3kdevrf4zg6hx8a60jv0gxe0ptgyfc6xkryqqqqqqqq".parse::<Offer>(),
1755                         Err(Bolt12ParseError::Decode(DecodeError::UnknownRequiredFeature)),
1756                 );
1757
1758                 // Malformed: empty
1759                 assert_eq!(
1760                         "lno1".parse::<Offer>(),
1761                         Err(Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription)),
1762                 );
1763
1764                 // Malformed: truncated at type
1765                 assert_eq!(
1766                         "lno1pg".parse::<Offer>(),
1767                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1768                 );
1769
1770                 // Malformed: truncated in length
1771                 assert_eq!(
1772                         "lno1pt7s".parse::<Offer>(),
1773                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1774                 );
1775
1776                 // Malformed: truncated after length
1777                 assert_eq!(
1778                         "lno1pgpq".parse::<Offer>(),
1779                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1780                 );
1781
1782                 // Malformed: truncated in description
1783                 assert_eq!(
1784                         "lno1pgpyz".parse::<Offer>(),
1785                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1786                 );
1787
1788                 // Malformed: invalid offer_chains length
1789                 assert_eq!(
1790                         "lno1qgqszzs9g9xyjs69zcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1791                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1792                 );
1793
1794                 // Malformed: truncated currency UTF-8
1795                 assert_eq!(
1796                         "lno1qcqcqzs9g9xyjs69zcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1797                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1798                 );
1799
1800                 // Malformed: invalid currency UTF-8
1801                 assert_eq!(
1802                         "lno1qcpgqsg2q4q5cj2rg5tzzqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqg".parse::<Offer>(),
1803                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1804                 );
1805
1806                 // Malformed: truncated description UTF-8
1807                 assert_eq!(
1808                         "lno1pgqcq93pqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqy".parse::<Offer>(),
1809                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1810                 );
1811
1812                 // Malformed: invalid description UTF-8
1813                 assert_eq!(
1814                         "lno1pgpgqsgkyypqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqs".parse::<Offer>(),
1815                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1816                 );
1817
1818                 // Malformed: truncated offer_paths
1819                 assert_eq!(
1820                         "lno1pgz5znzfgdz3qqgpzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1821                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1822                 );
1823
1824                 // Malformed: zero num_hops in blinded_path
1825                 assert_eq!(
1826                         "lno1pgz5znzfgdz3qqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1827                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1828                 );
1829
1830                 // Malformed: truncated onionmsg_hop in blinded_path
1831                 assert_eq!(
1832                         "lno1pgz5znzfgdz3qqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqspqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqgkyypqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqs".parse::<Offer>(),
1833                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1834                 );
1835
1836                 // Malformed: bad first_node_id in blinded_path
1837                 assert_eq!(
1838                         "lno1pgz5znzfgdz3qqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqspqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqgqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1839                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1840                 );
1841
1842                 // Malformed: bad blinding in blinded_path
1843                 assert_eq!(
1844                         "lno1pgz5znzfgdz3qqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcpqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqgqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1845                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1846                 );
1847
1848                 // Malformed: bad blinded_node_id in onionmsg_hop
1849                 assert_eq!(
1850                         "lno1pgz5znzfgdz3qqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqspqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqgqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1851                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1852                 );
1853
1854                 // Malformed: truncated issuer UTF-8
1855                 assert_eq!(
1856                         "lno1pgz5znzfgdz3yqvqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1857                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1858                 );
1859
1860                 // Malformed: invalid issuer UTF-8
1861                 assert_eq!(
1862                         "lno1pgz5znzfgdz3yq5qgytzzqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqg".parse::<Offer>(),
1863                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1864                 );
1865
1866                 // Malformed: invalid offer_node_id
1867                 assert_eq!(
1868                         "lno1pgz5znzfgdz3vggzqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvps".parse::<Offer>(),
1869                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1870                 );
1871
1872                 // Contains type >= 80
1873                 assert_eq!(
1874                         "lno1pgz5znzfgdz3vggzqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgp9qgr0u2xq4dh3kdevrf4zg6hx8a60jv0gxe0ptgyfc6xkryqqqqqqqq".parse::<Offer>(),
1875                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1876                 );
1877
1878                 // TODO: Resolved in spec https://github.com/lightning/bolts/pull/798/files#r1334851959
1879                 // Contains unknown feature 22
1880                 assert!(
1881                         "lno1pgx9getnwss8vetrw3hhyucvqdqqqqqkyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg".parse::<Offer>().is_ok()
1882                 );
1883
1884                 // Missing offer_description
1885                 assert_eq!(
1886                         "lno1zcss9mk8y3wkklfvevcrszlmu23kfrxh49px20665dqwmn4p72pksese".parse::<Offer>(),
1887                         Err(Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription)),
1888                 );
1889
1890                 // Missing offer_node_id"
1891                 assert_eq!(
1892                         "lno1pgx9getnwss8vetrw3hhyuc".parse::<Offer>(),
1893                         Err(Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingSigningPubkey)),
1894                 );
1895         }
1896 }