_ 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(pubkey)
  47 //!     .description("coffee, large".to_string())
  48 //!     .amount_msats(20_000)
  49 //!     .supported_quantity(Quantity::Unbounded)
  50 //!     .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
  51 //!     .issuer("Foo Bar".to_string())
  52 //!     .path(create_blinded_path())
  53 //!     .path(create_another_blinded_path())
  54 //!     .build()?;
  55 //!
  56 //! // Encode as a bech32 string for use in a QR code.
  57 //! let encoded_offer = offer.to_string();
  58 //!
  59 //! // Parse from a bech32 string after scanning from a QR code.
  60 //! let offer = encoded_offer.parse::<Offer>()?;
  61 //!
  62 //! // Encode offer as raw bytes.
  63 //! let mut bytes = Vec::new();
  64 //! offer.write(&mut bytes).unwrap();
  65 //!
  66 //! // Decode raw bytes into an offer.
  67 //! let offer = Offer::try_from(bytes)?;
  68 //! # Ok(())
  69 //! # }
  70 //! ```
  71 //!
  72 //! # Note
  73 //!
  74 //! If constructing an [`Offer`] for use with a [`ChannelManager`], use
  75 //! [`ChannelManager::create_offer_builder`] instead of [`OfferBuilder::new`].
  76 //!
  77 //! [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
  78 //! [`ChannelManager::create_offer_builder`]: crate::ln::channelmanager::ChannelManager::create_offer_builder
  79
  80 use bitcoin::blockdata::constants::ChainHash;
  81 use bitcoin::network::constants::Network;
  82 use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, self};
  83 use core::hash::{Hash, Hasher};
  84 use core::num::NonZeroU64;
  85 use core::ops::Deref;
  86 use core::str::FromStr;
  87 use core::time::Duration;
  88 use crate::sign::EntropySource;
  89 use crate::io;
  90 use crate::blinded_path::BlindedPath;
  91 use crate::ln::channelmanager::PaymentId;
  92 use crate::ln::features::OfferFeatures;
  93 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
  94 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
  95 use crate::offers::merkle::{TaggedHash, TlvStream};
  96 use crate::offers::parse::{Bech32Encode, Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
  97 use crate::offers::signer::{Metadata, MetadataMaterial, self};
  98 use crate::util::ser::{HighZeroBytesDroppedBigSize, Readable, WithoutLength, Writeable, Writer};
  99 use crate::util::string::PrintableString;
 100
 101 #[cfg(not(c_bindings))]
 102 use {
 103         crate::offers::invoice_request::{DerivedPayerId, ExplicitPayerId, InvoiceRequestBuilder},
 104 };
 105 #[cfg(c_bindings)]
 106 use {
 107         crate::offers::invoice_request::{InvoiceRequestWithDerivedPayerIdBuilder, InvoiceRequestWithExplicitPayerIdBuilder},
 108 };
 109
 110 #[allow(unused_imports)]
 111 use crate::prelude::*;
 112
 113 #[cfg(feature = "std")]
 114 use std::time::SystemTime;
 115
 116 pub(super) const IV_BYTES: &[u8; IV_LEN] = b"LDK Offer ~~~~~~";
 117
 118 /// An identifier for an [`Offer`] built using [`DerivedMetadata`].
 119 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 120 pub struct OfferId(pub [u8; 32]);
 121
 122 impl OfferId {
 123         const ID_TAG: &'static str = "LDK Offer ID";
 124
 125         fn from_valid_offer_tlv_stream(bytes: &[u8]) -> Self {
 126                 let tagged_hash = TaggedHash::from_valid_tlv_stream_bytes(Self::ID_TAG, bytes);
 127                 Self(tagged_hash.to_bytes())
 128         }
 129
 130         fn from_valid_invreq_tlv_stream(bytes: &[u8]) -> Self {
 131                 let tlv_stream = TlvStream::new(bytes).range(OFFER_TYPES);
 132                 let tagged_hash = TaggedHash::from_tlv_stream(Self::ID_TAG, tlv_stream);
 133                 Self(tagged_hash.to_bytes())
 134         }
 135 }
 136
 137 impl Writeable for OfferId {
 138         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 139                 self.0.write(w)
 140         }
 141 }
 142
 143 impl Readable for OfferId {
 144         fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
 145                 Ok(OfferId(Readable::read(r)?))
 146         }
 147 }
 148
 149 /// Builds an [`Offer`] for the "offer to be paid" flow.
 150 ///
 151 /// See [module-level documentation] for usage.
 152 ///
 153 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 154 ///
 155 /// [module-level documentation]: self
 156 pub struct OfferBuilder<'a, M: MetadataStrategy, T: secp256k1::Signing> {
 157         offer: OfferContents,
 158         metadata_strategy: core::marker::PhantomData<M>,
 159         secp_ctx: Option<&'a Secp256k1<T>>,
 160 }
 161
 162 /// Builds an [`Offer`] for the "offer to be paid" flow.
 163 ///
 164 /// See [module-level documentation] for usage.
 165 ///
 166 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 167 ///
 168 /// [module-level documentation]: self
 169 #[cfg(c_bindings)]
 170 pub struct OfferWithExplicitMetadataBuilder<'a> {
 171         offer: OfferContents,
 172         metadata_strategy: core::marker::PhantomData<ExplicitMetadata>,
 173         secp_ctx: Option<&'a Secp256k1<secp256k1::All>>,
 174 }
 175
 176 /// Builds an [`Offer`] for the "offer to be paid" flow.
 177 ///
 178 /// See [module-level documentation] for usage.
 179 ///
 180 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 181 ///
 182 /// [module-level documentation]: self
 183 #[cfg(c_bindings)]
 184 pub struct OfferWithDerivedMetadataBuilder<'a> {
 185         offer: OfferContents,
 186         metadata_strategy: core::marker::PhantomData<DerivedMetadata>,
 187         secp_ctx: Option<&'a Secp256k1<secp256k1::All>>,
 188 }
 189
 190 /// Indicates how [`Offer::metadata`] may be set.
 191 ///
 192 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 193 pub trait MetadataStrategy {}
 194
 195 /// [`Offer::metadata`] may be explicitly set or left empty.
 196 ///
 197 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 198 pub struct ExplicitMetadata {}
 199
 200 /// [`Offer::metadata`] will be derived.
 201 ///
 202 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 203 pub struct DerivedMetadata {}
 204
 205 impl MetadataStrategy for ExplicitMetadata {}
 206
 207 impl MetadataStrategy for DerivedMetadata {}
 208
 209 macro_rules! offer_explicit_metadata_builder_methods { (
 210         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr
 211 ) => {
 212         /// Creates a new builder for an offer using the [`Offer::signing_pubkey`] for signing invoices.
 213         /// The associated secret key must be remembered while the offer is valid.
 214         ///
 215         /// Use a different pubkey per offer to avoid correlating offers.
 216         ///
 217         /// # Note
 218         ///
 219         /// If constructing an [`Offer`] for use with a [`ChannelManager`], use
 220         /// [`ChannelManager::create_offer_builder`] instead of [`OfferBuilder::new`].
 221         ///
 222         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 223         /// [`ChannelManager::create_offer_builder`]: crate::ln::channelmanager::ChannelManager::create_offer_builder
 224         pub fn new(signing_pubkey: PublicKey) -> Self {
 225                 Self {
 226                         offer: OfferContents {
 227                                 chains: None, metadata: None, amount: None, description: None,
 228                                 features: OfferFeatures::empty(), absolute_expiry: None, issuer: None, paths: None,
 229                                 supported_quantity: Quantity::One, signing_pubkey: Some(signing_pubkey),
 230                         },
 231                         metadata_strategy: core::marker::PhantomData,
 232                         secp_ctx: None,
 233                 }
 234         }
 235
 236         /// Sets the [`Offer::metadata`] to the given bytes.
 237         ///
 238         /// Successive calls to this method will override the previous setting.
 239         pub fn metadata(mut $self: $self_type, metadata: Vec<u8>) -> Result<$return_type, Bolt12SemanticError> {
 240                 $self.offer.metadata = Some(Metadata::Bytes(metadata));
 241                 Ok($return_value)
 242         }
 243 } }
 244
 245 macro_rules! offer_derived_metadata_builder_methods { ($secp_context: ty) => {
 246         /// Similar to [`OfferBuilder::new`] except, if [`OfferBuilder::path`] is called, the signing
 247         /// pubkey is derived from the given [`ExpandedKey`] and [`EntropySource`]. This provides
 248         /// recipient privacy by using a different signing pubkey for each offer. Otherwise, the
 249         /// provided `node_id` is used for the signing pubkey.
 250         ///
 251         /// Also, sets the metadata when [`OfferBuilder::build`] is called such that it can be used by
 252         /// [`InvoiceRequest::verify`] to determine if the request was produced for the offer given an
 253         /// [`ExpandedKey`].
 254         ///
 255         /// [`InvoiceRequest::verify`]: crate::offers::invoice_request::InvoiceRequest::verify
 256         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 257         pub fn deriving_signing_pubkey<ES: Deref>(
 258                 node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 259                 secp_ctx: &'a Secp256k1<$secp_context>
 260         ) -> Self where ES::Target: EntropySource {
 261                 let nonce = Nonce::from_entropy_source(entropy_source);
 262                 let derivation_material = MetadataMaterial::new(nonce, expanded_key, IV_BYTES, None);
 263                 let metadata = Metadata::DerivedSigningPubkey(derivation_material);
 264                 Self {
 265                         offer: OfferContents {
 266                                 chains: None, metadata: Some(metadata), amount: None, description: None,
 267                                 features: OfferFeatures::empty(), absolute_expiry: None, issuer: None, paths: None,
 268                                 supported_quantity: Quantity::One, signing_pubkey: Some(node_id),
 269                         },
 270                         metadata_strategy: core::marker::PhantomData,
 271                         secp_ctx: Some(secp_ctx),
 272                 }
 273         }
 274 } }
 275
 276 macro_rules! offer_builder_methods { (
 277         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr $(, $self_mut: tt)?
 278 ) => {
 279         /// Adds the chain hash of the given [`Network`] to [`Offer::chains`]. If not called,
 280         /// the chain hash of [`Network::Bitcoin`] is assumed to be the only one supported.
 281         ///
 282         /// See [`Offer::chains`] on how this relates to the payment currency.
 283         ///
 284         /// Successive calls to this method will add another chain hash.
 285         pub fn chain($self: $self_type, network: Network) -> $return_type {
 286                 $self.chain_hash(ChainHash::using_genesis_block(network))
 287         }
 288
 289         /// Adds the [`ChainHash`] to [`Offer::chains`]. If not called, the chain hash of
 290         /// [`Network::Bitcoin`] is assumed to be the only one supported.
 291         ///
 292         /// See [`Offer::chains`] on how this relates to the payment currency.
 293         ///
 294         /// Successive calls to this method will add another chain hash.
 295         pub(crate) fn chain_hash($($self_mut)* $self: $self_type, chain: ChainHash) -> $return_type {
 296                 let chains = $self.offer.chains.get_or_insert_with(Vec::new);
 297                 if !chains.contains(&chain) {
 298                         chains.push(chain);
 299                 }
 300
 301                 $return_value
 302         }
 303
 304         /// Sets the [`Offer::amount`] as an [`Amount::Bitcoin`].
 305         ///
 306         /// Successive calls to this method will override the previous setting.
 307         pub fn amount_msats($self: $self_type, amount_msats: u64) -> $return_type {
 308                 $self.amount(Amount::Bitcoin { amount_msats })
 309         }
 310
 311         /// Sets the [`Offer::amount`].
 312         ///
 313         /// Successive calls to this method will override the previous setting.
 314         pub(super) fn amount($($self_mut)* $self: $self_type, amount: Amount) -> $return_type {
 315                 $self.offer.amount = Some(amount);
 316                 $return_value
 317         }
 318
 319         /// Sets the [`Offer::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
 320         /// already passed is valid and can be checked for using [`Offer::is_expired`].
 321         ///
 322         /// Successive calls to this method will override the previous setting.
 323         pub fn absolute_expiry($($self_mut)* $self: $self_type, absolute_expiry: Duration) -> $return_type {
 324                 $self.offer.absolute_expiry = Some(absolute_expiry);
 325                 $return_value
 326         }
 327
 328         /// Sets the [`Offer::description`].
 329         ///
 330         /// Successive calls to this method will override the previous setting.
 331         pub fn description($($self_mut)* $self: $self_type, description: String) -> $return_type {
 332                 $self.offer.description = Some(description);
 333                 $return_value
 334         }
 335
 336         /// Sets the [`Offer::issuer`].
 337         ///
 338         /// Successive calls to this method will override the previous setting.
 339         pub fn issuer($($self_mut)* $self: $self_type, issuer: String) -> $return_type {
 340                 $self.offer.issuer = Some(issuer);
 341                 $return_value
 342         }
 343
 344         /// Adds a blinded path to [`Offer::paths`]. Must include at least one path if only connected by
 345         /// private channels or if [`Offer::signing_pubkey`] is not a public node id.
 346         ///
 347         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 348         /// adding duplicate paths.
 349         pub fn path($($self_mut)* $self: $self_type, path: BlindedPath) -> $return_type {
 350                 $self.offer.paths.get_or_insert_with(Vec::new).push(path);
 351                 $return_value
 352         }
 353
 354         /// Sets the quantity of items for [`Offer::supported_quantity`]. If not called, defaults to
 355         /// [`Quantity::One`].
 356         ///
 357         /// Successive calls to this method will override the previous setting.
 358         pub fn supported_quantity($($self_mut)* $self: $self_type, quantity: Quantity) -> $return_type {
 359                 $self.offer.supported_quantity = quantity;
 360                 $return_value
 361         }
 362
 363         /// Builds an [`Offer`] from the builder's settings.
 364         pub fn build($($self_mut)* $self: $self_type) -> Result<Offer, Bolt12SemanticError> {
 365                 match $self.offer.amount {
 366                         Some(Amount::Bitcoin { amount_msats }) => {
 367                                 if amount_msats > MAX_VALUE_MSAT {
 368                                         return Err(Bolt12SemanticError::InvalidAmount);
 369                                 }
 370                         },
 371                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 372                         None => {},
 373                 }
 374
 375                 if $self.offer.amount.is_some() && $self.offer.description.is_none() {
 376                         $self.offer.description = Some(String::new());
 377                 }
 378
 379                 if let Some(chains) = &$self.offer.chains {
 380                         if chains.len() == 1 && chains[0] == $self.offer.implied_chain() {
 381                                 $self.offer.chains = None;
 382                         }
 383                 }
 384
 385                 Ok($self.build_without_checks())
 386         }
 387
 388         fn build_without_checks($($self_mut)* $self: $self_type) -> Offer {
 389                 // Create the metadata for stateless verification of an InvoiceRequest.
 390                 if let Some(mut metadata) = $self.offer.metadata.take() {
 391                         if metadata.has_derivation_material() {
 392                                 if $self.offer.paths.is_none() {
 393                                         metadata = metadata.without_keys();
 394                                 }
 395
 396                                 let mut tlv_stream = $self.offer.as_tlv_stream();
 397                                 debug_assert_eq!(tlv_stream.metadata, None);
 398                                 tlv_stream.metadata = None;
 399                                 if metadata.derives_recipient_keys() {
 400                                         tlv_stream.node_id = None;
 401                                 }
 402
 403                                 let (derived_metadata, keys) = metadata.derive_from(tlv_stream, $self.secp_ctx);
 404                                 metadata = derived_metadata;
 405                                 if let Some(keys) = keys {
 406                                         $self.offer.signing_pubkey = Some(keys.public_key());
 407                                 }
 408                         }
 409
 410                         $self.offer.metadata = Some(metadata);
 411                 }
 412
 413                 let mut bytes = Vec::new();
 414                 $self.offer.write(&mut bytes).unwrap();
 415
 416                 let id = OfferId::from_valid_offer_tlv_stream(&bytes);
 417
 418                 Offer {
 419                         bytes,
 420                         #[cfg(not(c_bindings))]
 421                         contents: $self.offer,
 422                         #[cfg(c_bindings)]
 423                         contents: $self.offer.clone(),
 424                         id,
 425                 }
 426         }
 427 } }
 428
 429 #[cfg(test)]
 430 macro_rules! offer_builder_test_methods { (
 431         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr $(, $self_mut: tt)?
 432 ) => {
 433         #[cfg_attr(c_bindings, allow(dead_code))]
 434         fn features_unchecked($($self_mut)* $self: $self_type, features: OfferFeatures) -> $return_type {
 435                 $self.offer.features = features;
 436                 $return_value
 437         }
 438
 439         #[cfg_attr(c_bindings, allow(dead_code))]
 440         pub(crate) fn clear_chains($($self_mut)* $self: $self_type) -> $return_type {
 441                 $self.offer.chains = None;
 442                 $return_value
 443         }
 444
 445         #[cfg_attr(c_bindings, allow(dead_code))]
 446         pub(crate) fn clear_paths($($self_mut)* $self: $self_type) -> $return_type {
 447                 $self.offer.paths = None;
 448                 $return_value
 449         }
 450
 451         #[cfg_attr(c_bindings, allow(dead_code))]
 452         pub(crate) fn clear_signing_pubkey($($self_mut)* $self: $self_type) -> $return_type {
 453                 $self.offer.signing_pubkey = None;
 454                 $return_value
 455         }
 456
 457         #[cfg_attr(c_bindings, allow(dead_code))]
 458         pub(super) fn build_unchecked($self: $self_type) -> Offer {
 459                 $self.build_without_checks()
 460         }
 461 } }
 462
 463 impl<'a, M: MetadataStrategy, T: secp256k1::Signing> OfferBuilder<'a, M, T> {
 464         offer_builder_methods!(self, Self, Self, self, mut);
 465
 466         #[cfg(test)]
 467         offer_builder_test_methods!(self, Self, Self, self, mut);
 468 }
 469
 470 impl<'a> OfferBuilder<'a, ExplicitMetadata, secp256k1::SignOnly> {
 471         offer_explicit_metadata_builder_methods!(self, Self, Self, self);
 472 }
 473
 474 impl<'a, T: secp256k1::Signing> OfferBuilder<'a, DerivedMetadata, T> {
 475         offer_derived_metadata_builder_methods!(T);
 476 }
 477
 478 #[cfg(all(c_bindings, not(test)))]
 479 impl<'a> OfferWithExplicitMetadataBuilder<'a> {
 480         offer_explicit_metadata_builder_methods!(self, &mut Self, (), ());
 481         offer_builder_methods!(self, &mut Self, (), ());
 482 }
 483
 484 #[cfg(all(c_bindings, test))]
 485 impl<'a> OfferWithExplicitMetadataBuilder<'a> {
 486         offer_explicit_metadata_builder_methods!(self, &mut Self, &mut Self, self);
 487         offer_builder_methods!(self, &mut Self, &mut Self, self);
 488         offer_builder_test_methods!(self, &mut Self, &mut Self, self);
 489 }
 490
 491 #[cfg(all(c_bindings, not(test)))]
 492 impl<'a> OfferWithDerivedMetadataBuilder<'a> {
 493         offer_derived_metadata_builder_methods!(secp256k1::All);
 494         offer_builder_methods!(self, &mut Self, (), ());
 495 }
 496
 497 #[cfg(all(c_bindings, test))]
 498 impl<'a> OfferWithDerivedMetadataBuilder<'a> {
 499         offer_derived_metadata_builder_methods!(secp256k1::All);
 500         offer_builder_methods!(self, &mut Self, &mut Self, self);
 501         offer_builder_test_methods!(self, &mut Self, &mut Self, self);
 502 }
 503
 504 #[cfg(c_bindings)]
 505 impl<'a> From<OfferBuilder<'a, DerivedMetadata, secp256k1::All>>
 506 for OfferWithDerivedMetadataBuilder<'a> {
 507         fn from(builder: OfferBuilder<'a, DerivedMetadata, secp256k1::All>) -> Self {
 508                 let OfferBuilder { offer, metadata_strategy, secp_ctx } = builder;
 509
 510                 Self { offer, metadata_strategy, secp_ctx }
 511         }
 512 }
 513
 514 #[cfg(c_bindings)]
 515 impl<'a> From<OfferWithDerivedMetadataBuilder<'a>>
 516 for OfferBuilder<'a, DerivedMetadata, secp256k1::All> {
 517         fn from(builder: OfferWithDerivedMetadataBuilder<'a>) -> Self {
 518                 let OfferWithDerivedMetadataBuilder { offer, metadata_strategy, secp_ctx } = builder;
 519
 520                 Self { offer, metadata_strategy, secp_ctx }
 521         }
 522 }
 523
 524 /// An `Offer` is a potentially long-lived proposal for payment of a good or service.
 525 ///
 526 /// An offer is a precursor to an [`InvoiceRequest`]. A merchant publishes an offer from which a
 527 /// customer may request an [`Bolt12Invoice`] for a specific quantity and using an amount sufficient
 528 /// to cover that quantity (i.e., at least `quantity * amount`). See [`Offer::amount`].
 529 ///
 530 /// Offers may be denominated in currency other than bitcoin but are ultimately paid using the
 531 /// latter.
 532 ///
 533 /// Through the use of [`BlindedPath`]s, offers provide recipient privacy.
 534 ///
 535 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 536 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 537 #[derive(Clone, Debug)]
 538 pub struct Offer {
 539         // The serialized offer. Needed when creating an `InvoiceRequest` if the offer contains unknown
 540         // fields.
 541         pub(super) bytes: Vec<u8>,
 542         pub(super) contents: OfferContents,
 543         id: OfferId,
 544 }
 545
 546 /// The contents of an [`Offer`], which may be shared with an [`InvoiceRequest`] or a
 547 /// [`Bolt12Invoice`].
 548 ///
 549 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 550 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 551 #[derive(Clone, Debug)]
 552 #[cfg_attr(test, derive(PartialEq))]
 553 pub(super) struct OfferContents {
 554         chains: Option<Vec<ChainHash>>,
 555         metadata: Option<Metadata>,
 556         amount: Option<Amount>,
 557         description: Option<String>,
 558         features: OfferFeatures,
 559         absolute_expiry: Option<Duration>,
 560         issuer: Option<String>,
 561         paths: Option<Vec<BlindedPath>>,
 562         supported_quantity: Quantity,
 563         signing_pubkey: Option<PublicKey>,
 564 }
 565
 566 macro_rules! offer_accessors { ($self: ident, $contents: expr) => {
 567         // TODO: Return a slice once ChainHash has constants.
 568         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1283
 569         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1286
 570         /// The chains that may be used when paying a requested invoice (e.g., bitcoin mainnet).
 571         /// Payments must be denominated in units of the minimal lightning-payable unit (e.g., msats)
 572         /// for the selected chain.
 573         pub fn chains(&$self) -> Vec<bitcoin::blockdata::constants::ChainHash> {
 574                 $contents.chains()
 575         }
 576
 577         // TODO: Link to corresponding method in `InvoiceRequest`.
 578         /// Opaque bytes set by the originator. Useful for authentication and validating fields since it
 579         /// is reflected in `invoice_request` messages along with all the other fields from the `offer`.
 580         pub fn metadata(&$self) -> Option<&Vec<u8>> {
 581                 $contents.metadata()
 582         }
 583
 584         /// The minimum amount required for a successful payment of a single item.
 585         pub fn amount(&$self) -> Option<&$crate::offers::offer::Amount> {
 586                 $contents.amount()
 587         }
 588
 589         /// A complete description of the purpose of the payment. Intended to be displayed to the user
 590         /// but with the caveat that it has not been verified in any way.
 591         pub fn description(&$self) -> Option<$crate::util::string::PrintableString> {
 592                 $contents.description()
 593         }
 594
 595         /// Features pertaining to the offer.
 596         pub fn offer_features(&$self) -> &$crate::ln::features::OfferFeatures {
 597                 &$contents.features()
 598         }
 599
 600         /// Duration since the Unix epoch when an invoice should no longer be requested.
 601         ///
 602         /// If `None`, the offer does not expire.
 603         pub fn absolute_expiry(&$self) -> Option<core::time::Duration> {
 604                 $contents.absolute_expiry()
 605         }
 606
 607         /// The issuer of the offer, possibly beginning with `user@domain` or `domain`. Intended to be
 608         /// displayed to the user but with the caveat that it has not been verified in any way.
 609         pub fn issuer(&$self) -> Option<$crate::util::string::PrintableString> {
 610                 $contents.issuer()
 611         }
 612
 613         /// Paths to the recipient originating from publicly reachable nodes. Blinded paths provide
 614         /// recipient privacy by obfuscating its node id.
 615         pub fn paths(&$self) -> &[$crate::blinded_path::BlindedPath] {
 616                 $contents.paths()
 617         }
 618
 619         /// The quantity of items supported.
 620         pub fn supported_quantity(&$self) -> $crate::offers::offer::Quantity {
 621                 $contents.supported_quantity()
 622         }
 623
 624         /// The public key used by the recipient to sign invoices.
 625         pub fn signing_pubkey(&$self) -> Option<bitcoin::secp256k1::PublicKey> {
 626                 $contents.signing_pubkey()
 627         }
 628 } }
 629
 630 impl Offer {
 631         offer_accessors!(self, self.contents);
 632
 633         /// Returns the id of the offer.
 634         pub fn id(&self) -> OfferId {
 635                 self.id
 636         }
 637
 638         pub(super) fn implied_chain(&self) -> ChainHash {
 639                 self.contents.implied_chain()
 640         }
 641
 642         /// Returns whether the given chain is supported by the offer.
 643         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 644                 self.contents.supports_chain(chain)
 645         }
 646
 647         /// Whether the offer has expired.
 648         #[cfg(feature = "std")]
 649         pub fn is_expired(&self) -> bool {
 650                 self.contents.is_expired()
 651         }
 652
 653         /// Whether the offer has expired given the duration since the Unix epoch.
 654         pub fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 655                 self.contents.is_expired_no_std(duration_since_epoch)
 656         }
 657
 658         /// Returns whether the given quantity is valid for the offer.
 659         pub fn is_valid_quantity(&self, quantity: u64) -> bool {
 660                 self.contents.is_valid_quantity(quantity)
 661         }
 662
 663         /// Returns whether a quantity is expected in an [`InvoiceRequest`] for the offer.
 664         ///
 665         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 666         pub fn expects_quantity(&self) -> bool {
 667                 self.contents.expects_quantity()
 668         }
 669 }
 670
 671 macro_rules! request_invoice_derived_payer_id { ($self: ident, $builder: ty) => {
 672         /// Similar to [`Offer::request_invoice`] except it:
 673         /// - derives the [`InvoiceRequest::payer_id`] such that a different key can be used for each
 674         ///   request,
 675         /// - sets [`InvoiceRequest::payer_metadata`] when [`InvoiceRequestBuilder::build`] is called
 676         ///   such that it can be used by [`Bolt12Invoice::verify`] to determine if the invoice was
 677         ///   requested using a base [`ExpandedKey`] from which the payer id was derived, and
 678         /// - includes the [`PaymentId`] encrypted in [`InvoiceRequest::payer_metadata`] so that it can
 679         ///   be used when sending the payment for the requested invoice.
 680         ///
 681         /// Useful to protect the sender's privacy.
 682         ///
 683         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 684         /// [`InvoiceRequest::payer_metadata`]: crate::offers::invoice_request::InvoiceRequest::payer_metadata
 685         /// [`Bolt12Invoice::verify`]: crate::offers::invoice::Bolt12Invoice::verify
 686         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 687         pub fn request_invoice_deriving_payer_id<
 688                 'a, 'b, ES: Deref,
 689                 #[cfg(not(c_bindings))]
 690                 T: secp256k1::Signing
 691         >(
 692                 &'a $self, expanded_key: &ExpandedKey, entropy_source: ES,
 693                 #[cfg(not(c_bindings))]
 694                 secp_ctx: &'b Secp256k1<T>,
 695                 #[cfg(c_bindings)]
 696                 secp_ctx: &'b Secp256k1<secp256k1::All>,
 697                 payment_id: PaymentId
 698         ) -> Result<$builder, Bolt12SemanticError>
 699         where
 700                 ES::Target: EntropySource,
 701         {
 702                 if $self.offer_features().requires_unknown_bits() {
 703                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 704                 }
 705
 706                 Ok(<$builder>::deriving_payer_id($self, expanded_key, entropy_source, secp_ctx, payment_id))
 707         }
 708 } }
 709
 710 macro_rules! request_invoice_explicit_payer_id { ($self: ident, $builder: ty) => {
 711         /// Similar to [`Offer::request_invoice_deriving_payer_id`] except uses `payer_id` for the
 712         /// [`InvoiceRequest::payer_id`] instead of deriving a different key for each request.
 713         ///
 714         /// Useful for recurring payments using the same `payer_id` with different invoices.
 715         ///
 716         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 717         pub fn request_invoice_deriving_metadata<ES: Deref>(
 718                 &$self, payer_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 719                 payment_id: PaymentId
 720         ) -> Result<$builder, Bolt12SemanticError>
 721         where
 722                 ES::Target: EntropySource,
 723         {
 724                 if $self.offer_features().requires_unknown_bits() {
 725                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 726                 }
 727
 728                 Ok(<$builder>::deriving_metadata($self, payer_id, expanded_key, entropy_source, payment_id))
 729         }
 730
 731         /// Creates an [`InvoiceRequestBuilder`] for the offer with the given `metadata` and `payer_id`,
 732         /// which will be reflected in the `Bolt12Invoice` response.
 733         ///
 734         /// The `metadata` is useful for including information about the derivation of `payer_id` such
 735         /// that invoice response handling can be stateless. Also serves as payer-provided entropy while
 736         /// hashing in the signature calculation.
 737         ///
 738         /// This should not leak any information such as by using a simple BIP-32 derivation path.
 739         /// Otherwise, payments may be correlated.
 740         ///
 741         /// Errors if the offer contains unknown required features.
 742         ///
 743         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 744         pub fn request_invoice(
 745                 &$self, metadata: Vec<u8>, payer_id: PublicKey
 746         ) -> Result<$builder, Bolt12SemanticError> {
 747                 if $self.offer_features().requires_unknown_bits() {
 748                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 749                 }
 750
 751                 Ok(<$builder>::new($self, metadata, payer_id))
 752         }
 753 } }
 754
 755 #[cfg(not(c_bindings))]
 756 impl Offer {
 757         request_invoice_derived_payer_id!(self, InvoiceRequestBuilder<'a, 'b, DerivedPayerId, T>);
 758         request_invoice_explicit_payer_id!(self, InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>);
 759 }
 760
 761 #[cfg(c_bindings)]
 762 impl Offer {
 763         request_invoice_derived_payer_id!(self, InvoiceRequestWithDerivedPayerIdBuilder<'a, 'b>);
 764         request_invoice_explicit_payer_id!(self, InvoiceRequestWithExplicitPayerIdBuilder);
 765 }
 766
 767 #[cfg(test)]
 768 impl Offer {
 769         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 770                 self.contents.as_tlv_stream()
 771         }
 772 }
 773
 774 impl AsRef<[u8]> for Offer {
 775         fn as_ref(&self) -> &[u8] {
 776                 &self.bytes
 777         }
 778 }
 779
 780 impl PartialEq for Offer {
 781         fn eq(&self, other: &Self) -> bool {
 782                 self.bytes.eq(&other.bytes)
 783         }
 784 }
 785
 786 impl Eq for Offer {}
 787
 788 impl Hash for Offer {
 789         fn hash<H: Hasher>(&self, state: &mut H) {
 790                 self.bytes.hash(state);
 791         }
 792 }
 793
 794 impl OfferContents {
 795         pub fn chains(&self) -> Vec<ChainHash> {
 796                 self.chains.as_ref().cloned().unwrap_or_else(|| vec![self.implied_chain()])
 797         }
 798
 799         pub fn implied_chain(&self) -> ChainHash {
 800                 ChainHash::using_genesis_block(Network::Bitcoin)
 801         }
 802
 803         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 804                 self.chains().contains(&chain)
 805         }
 806
 807         pub fn metadata(&self) -> Option<&Vec<u8>> {
 808                 self.metadata.as_ref().and_then(|metadata| metadata.as_bytes())
 809         }
 810
 811         pub fn amount(&self) -> Option<&Amount> {
 812                 self.amount.as_ref()
 813         }
 814
 815         pub fn description(&self) -> Option<PrintableString> {
 816                 self.description.as_ref().map(|description| PrintableString(description))
 817         }
 818
 819         pub fn features(&self) -> &OfferFeatures {
 820                 &self.features
 821         }
 822
 823         pub fn absolute_expiry(&self) -> Option<Duration> {
 824                 self.absolute_expiry
 825         }
 826
 827         #[cfg(feature = "std")]
 828         pub(super) fn is_expired(&self) -> bool {
 829                 SystemTime::UNIX_EPOCH
 830                         .elapsed()
 831                         .map(|duration_since_epoch| self.is_expired_no_std(duration_since_epoch))
 832                         .unwrap_or(false)
 833         }
 834
 835         pub(super) fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 836                 self.absolute_expiry
 837                         .map(|absolute_expiry| duration_since_epoch > absolute_expiry)
 838                         .unwrap_or(false)
 839         }
 840
 841         pub fn issuer(&self) -> Option<PrintableString> {
 842                 self.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 843         }
 844
 845         pub fn paths(&self) -> &[BlindedPath] {
 846                 self.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 847         }
 848
 849         pub(super) fn check_amount_msats_for_quantity(
 850                 &self, amount_msats: Option<u64>, quantity: Option<u64>
 851         ) -> Result<(), Bolt12SemanticError> {
 852                 let offer_amount_msats = match self.amount {
 853                         None => 0,
 854                         Some(Amount::Bitcoin { amount_msats }) => amount_msats,
 855                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 856                 };
 857
 858                 if !self.expects_quantity() || quantity.is_some() {
 859                         let expected_amount_msats = offer_amount_msats.checked_mul(quantity.unwrap_or(1))
 860                                 .ok_or(Bolt12SemanticError::InvalidAmount)?;
 861                         let amount_msats = amount_msats.unwrap_or(expected_amount_msats);
 862
 863                         if amount_msats < expected_amount_msats {
 864                                 return Err(Bolt12SemanticError::InsufficientAmount);
 865                         }
 866
 867                         if amount_msats > MAX_VALUE_MSAT {
 868                                 return Err(Bolt12SemanticError::InvalidAmount);
 869                         }
 870                 }
 871
 872                 Ok(())
 873         }
 874
 875         pub fn supported_quantity(&self) -> Quantity {
 876                 self.supported_quantity
 877         }
 878
 879         pub(super) fn check_quantity(&self, quantity: Option<u64>) -> Result<(), Bolt12SemanticError> {
 880                 let expects_quantity = self.expects_quantity();
 881                 match quantity {
 882                         None if expects_quantity => Err(Bolt12SemanticError::MissingQuantity),
 883                         Some(_) if !expects_quantity => Err(Bolt12SemanticError::UnexpectedQuantity),
 884                         Some(quantity) if !self.is_valid_quantity(quantity) => {
 885                                 Err(Bolt12SemanticError::InvalidQuantity)
 886                         },
 887                         _ => Ok(()),
 888                 }
 889         }
 890
 891         fn is_valid_quantity(&self, quantity: u64) -> bool {
 892                 match self.supported_quantity {
 893                         Quantity::Bounded(n) => quantity <= n.get(),
 894                         Quantity::Unbounded => quantity > 0,
 895                         Quantity::One => quantity == 1,
 896                 }
 897         }
 898
 899         fn expects_quantity(&self) -> bool {
 900                 match self.supported_quantity {
 901                         Quantity::Bounded(_) => true,
 902                         Quantity::Unbounded => true,
 903                         Quantity::One => false,
 904                 }
 905         }
 906
 907         pub(super) fn signing_pubkey(&self) -> Option<PublicKey> {
 908                 self.signing_pubkey
 909         }
 910
 911         /// Verifies that the offer metadata was produced from the offer in the TLV stream.
 912         pub(super) fn verify<T: secp256k1::Signing>(
 913                 &self, bytes: &[u8], key: &ExpandedKey, secp_ctx: &Secp256k1<T>
 914         ) -> Result<(OfferId, Option<KeyPair>), ()> {
 915                 match self.metadata() {
 916                         Some(metadata) => {
 917                                 let tlv_stream = TlvStream::new(bytes).range(OFFER_TYPES).filter(|record| {
 918                                         match record.r#type {
 919                                                 OFFER_METADATA_TYPE => false,
 920                                                 OFFER_NODE_ID_TYPE => {
 921                                                         !self.metadata.as_ref().unwrap().derives_recipient_keys()
 922                                                 },
 923                                                 _ => true,
 924                                         }
 925                                 });
 926                                 let signing_pubkey = match self.signing_pubkey() {
 927                                         Some(signing_pubkey) => signing_pubkey,
 928                                         None => return Err(()),
 929                                 };
 930                                 let keys = signer::verify_recipient_metadata(
 931                                         metadata, key, IV_BYTES, signing_pubkey, tlv_stream, secp_ctx
 932                                 )?;
 933
 934                                 let offer_id = OfferId::from_valid_invreq_tlv_stream(bytes);
 935
 936                                 Ok((offer_id, keys))
 937                         },
 938                         None => Err(()),
 939                 }
 940         }
 941
 942         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 943                 let (currency, amount) = match &self.amount {
 944                         None => (None, None),
 945                         Some(Amount::Bitcoin { amount_msats }) => (None, Some(*amount_msats)),
 946                         Some(Amount::Currency { iso4217_code, amount }) => (
 947                                 Some(iso4217_code), Some(*amount)
 948                         ),
 949                 };
 950
 951                 let features = {
 952                         if self.features == OfferFeatures::empty() { None } else { Some(&self.features) }
 953                 };
 954
 955                 OfferTlvStreamRef {
 956                         chains: self.chains.as_ref(),
 957                         metadata: self.metadata(),
 958                         currency,
 959                         amount,
 960                         description: self.description.as_ref(),
 961                         features,
 962                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 963                         paths: self.paths.as_ref(),
 964                         issuer: self.issuer.as_ref(),
 965                         quantity_max: self.supported_quantity.to_tlv_record(),
 966                         node_id: self.signing_pubkey.as_ref(),
 967                 }
 968         }
 969 }
 970
 971 impl Writeable for Offer {
 972         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 973                 WithoutLength(&self.bytes).write(writer)
 974         }
 975 }
 976
 977 impl Writeable for OfferContents {
 978         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 979                 self.as_tlv_stream().write(writer)
 980         }
 981 }
 982
 983 /// The minimum amount required for an item in an [`Offer`], denominated in either bitcoin or
 984 /// another currency.
 985 #[derive(Clone, Debug, PartialEq)]
 986 pub enum Amount {
 987         /// An amount of bitcoin.
 988         Bitcoin {
 989                 /// The amount in millisatoshi.
 990                 amount_msats: u64,
 991         },
 992         /// An amount of currency specified using ISO 4712.
 993         Currency {
 994                 /// The currency that the amount is denominated in.
 995                 iso4217_code: CurrencyCode,
 996                 /// The amount in the currency unit adjusted by the ISO 4712 exponent (e.g., USD cents).
 997                 amount: u64,
 998         },
 999 }
1000
1001 /// An ISO 4712 three-letter currency code (e.g., USD).
1002 pub type CurrencyCode = [u8; 3];
1003
1004 /// Quantity of items supported by an [`Offer`].
1005 #[derive(Clone, Copy, Debug, PartialEq)]
1006 pub enum Quantity {
1007         /// Up to a specific number of items (inclusive). Use when more than one item can be requested
1008         /// but is limited (e.g., because of per customer or inventory limits).
1009         ///
1010         /// May be used with `NonZeroU64::new(1)` but prefer to use [`Quantity::One`] if only one item
1011         /// is supported.
1012         Bounded(NonZeroU64),
1013         /// One or more items. Use when more than one item can be requested without any limit.
1014         Unbounded,
1015         /// Only one item. Use when only a single item can be requested.
1016         One,
1017 }
1018
1019 impl Quantity {
1020         fn to_tlv_record(&self) -> Option<u64> {
1021                 match self {
1022                         Quantity::Bounded(n) => Some(n.get()),
1023                         Quantity::Unbounded => Some(0),
1024                         Quantity::One => None,
1025                 }
1026         }
1027 }
1028
1029 /// Valid type range for offer TLV records.
1030 pub(super) const OFFER_TYPES: core::ops::Range<u64> = 1..80;
1031
1032 /// TLV record type for [`Offer::metadata`].
1033 const OFFER_METADATA_TYPE: u64 = 4;
1034
1035 /// TLV record type for [`Offer::signing_pubkey`].
1036 const OFFER_NODE_ID_TYPE: u64 = 22;
1037
1038 tlv_stream!(OfferTlvStream, OfferTlvStreamRef, OFFER_TYPES, {
1039         (2, chains: (Vec<ChainHash>, WithoutLength)),
1040         (OFFER_METADATA_TYPE, metadata: (Vec<u8>, WithoutLength)),
1041         (6, currency: CurrencyCode),
1042         (8, amount: (u64, HighZeroBytesDroppedBigSize)),
1043         (10, description: (String, WithoutLength)),
1044         (12, features: (OfferFeatures, WithoutLength)),
1045         (14, absolute_expiry: (u64, HighZeroBytesDroppedBigSize)),
1046         (16, paths: (Vec<BlindedPath>, WithoutLength)),
1047         (18, issuer: (String, WithoutLength)),
1048         (20, quantity_max: (u64, HighZeroBytesDroppedBigSize)),
1049         (OFFER_NODE_ID_TYPE, node_id: PublicKey),
1050 });
1051
1052 impl Bech32Encode for Offer {
1053         const BECH32_HRP: &'static str = "lno";
1054 }
1055
1056 impl FromStr for Offer {
1057         type Err = Bolt12ParseError;
1058
1059         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
1060                 Self::from_bech32_str(s)
1061         }
1062 }
1063
1064 impl TryFrom<Vec<u8>> for Offer {
1065         type Error = Bolt12ParseError;
1066
1067         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
1068                 let offer = ParsedMessage::<OfferTlvStream>::try_from(bytes)?;
1069                 let ParsedMessage { bytes, tlv_stream } = offer;
1070                 let contents = OfferContents::try_from(tlv_stream)?;
1071                 let id = OfferId::from_valid_offer_tlv_stream(&bytes);
1072
1073                 Ok(Offer { bytes, contents, id })
1074         }
1075 }
1076
1077 impl TryFrom<OfferTlvStream> for OfferContents {
1078         type Error = Bolt12SemanticError;
1079
1080         fn try_from(tlv_stream: OfferTlvStream) -> Result<Self, Self::Error> {
1081                 let OfferTlvStream {
1082                         chains, metadata, currency, amount, description, features, absolute_expiry, paths,
1083                         issuer, quantity_max, node_id,
1084                 } = tlv_stream;
1085
1086                 let metadata = metadata.map(|metadata| Metadata::Bytes(metadata));
1087
1088                 let amount = match (currency, amount) {
1089                         (None, None) => None,
1090                         (None, Some(amount_msats)) if amount_msats > MAX_VALUE_MSAT => {
1091                                 return Err(Bolt12SemanticError::InvalidAmount);
1092                         },
1093                         (None, Some(amount_msats)) => Some(Amount::Bitcoin { amount_msats }),
1094                         (Some(_), None) => return Err(Bolt12SemanticError::MissingAmount),
1095                         (Some(iso4217_code), Some(amount)) => Some(Amount::Currency { iso4217_code, amount }),
1096                 };
1097
1098                 if amount.is_some() && description.is_none() {
1099                         return Err(Bolt12SemanticError::MissingDescription);
1100                 }
1101
1102                 let features = features.unwrap_or_else(OfferFeatures::empty);
1103
1104                 let absolute_expiry = absolute_expiry
1105                         .map(|seconds_from_epoch| Duration::from_secs(seconds_from_epoch));
1106
1107                 let supported_quantity = match quantity_max {
1108                         None => Quantity::One,
1109                         Some(0) => Quantity::Unbounded,
1110                         Some(n) => Quantity::Bounded(NonZeroU64::new(n).unwrap()),
1111                 };
1112
1113                 let (signing_pubkey, paths) = match (node_id, paths) {
1114                         (None, None) => return Err(Bolt12SemanticError::MissingSigningPubkey),
1115                         (_, Some(paths)) if paths.is_empty() => return Err(Bolt12SemanticError::MissingPaths),
1116                         (node_id, paths) => (node_id, paths),
1117                 };
1118
1119                 Ok(OfferContents {
1120                         chains, metadata, amount, description, features, absolute_expiry, issuer, paths,
1121                         supported_quantity, signing_pubkey,
1122                 })
1123         }
1124 }
1125
1126 impl core::fmt::Display for Offer {
1127         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
1128                 self.fmt_bech32_str(f)
1129         }
1130 }
1131
1132 #[cfg(test)]
1133 mod tests {
1134         use super::{Amount, Offer, OfferTlvStreamRef, Quantity};
1135         #[cfg(not(c_bindings))]
1136         use {
1137                 super::OfferBuilder,
1138         };
1139         #[cfg(c_bindings)]
1140         use {
1141                 super::OfferWithExplicitMetadataBuilder as OfferBuilder,
1142         };
1143
1144         use bitcoin::blockdata::constants::ChainHash;
1145         use bitcoin::network::constants::Network;
1146         use bitcoin::secp256k1::Secp256k1;
1147         use core::num::NonZeroU64;
1148         use core::time::Duration;
1149         use crate::blinded_path::{BlindedHop, BlindedPath, IntroductionNode};
1150         use crate::sign::KeyMaterial;
1151         use crate::ln::features::OfferFeatures;
1152         use crate::ln::inbound_payment::ExpandedKey;
1153         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
1154         use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
1155         use crate::offers::test_utils::*;
1156         use crate::util::ser::{BigSize, Writeable};
1157         use crate::util::string::PrintableString;
1158
1159         #[test]
1160         fn builds_offer_with_defaults() {
1161                 let offer = OfferBuilder::new(pubkey(42)).build().unwrap();
1162
1163                 let mut buffer = Vec::new();
1164                 offer.write(&mut buffer).unwrap();
1165
1166                 assert_eq!(offer.bytes, buffer.as_slice());
1167                 assert_eq!(offer.chains(), vec![ChainHash::using_genesis_block(Network::Bitcoin)]);
1168                 assert!(offer.supports_chain(ChainHash::using_genesis_block(Network::Bitcoin)));
1169                 assert_eq!(offer.metadata(), None);
1170                 assert_eq!(offer.amount(), None);
1171                 assert_eq!(offer.description(), None);
1172                 assert_eq!(offer.offer_features(), &OfferFeatures::empty());
1173                 assert_eq!(offer.absolute_expiry(), None);
1174                 #[cfg(feature = "std")]
1175                 assert!(!offer.is_expired());
1176                 assert_eq!(offer.paths(), &[]);
1177                 assert_eq!(offer.issuer(), None);
1178                 assert_eq!(offer.supported_quantity(), Quantity::One);
1179                 assert_eq!(offer.signing_pubkey(), Some(pubkey(42)));
1180
1181                 assert_eq!(
1182                         offer.as_tlv_stream(),
1183                         OfferTlvStreamRef {
1184                                 chains: None,
1185                                 metadata: None,
1186                                 currency: None,
1187                                 amount: None,
1188                                 description: None,
1189                                 features: None,
1190                                 absolute_expiry: None,
1191                                 paths: None,
1192                                 issuer: None,
1193                                 quantity_max: None,
1194                                 node_id: Some(&pubkey(42)),
1195                         },
1196                 );
1197
1198                 if let Err(e) = Offer::try_from(buffer) {
1199                         panic!("error parsing offer: {:?}", e);
1200                 }
1201         }
1202
1203         #[test]
1204         fn builds_offer_with_chains() {
1205                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
1206                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
1207
1208                 let offer = OfferBuilder::new(pubkey(42))
1209                         .chain(Network::Bitcoin)
1210                         .build()
1211                         .unwrap();
1212                 assert!(offer.supports_chain(mainnet));
1213                 assert_eq!(offer.chains(), vec![mainnet]);
1214                 assert_eq!(offer.as_tlv_stream().chains, None);
1215
1216                 let offer = OfferBuilder::new(pubkey(42))
1217                         .chain(Network::Testnet)
1218                         .build()
1219                         .unwrap();
1220                 assert!(offer.supports_chain(testnet));
1221                 assert_eq!(offer.chains(), vec![testnet]);
1222                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
1223
1224                 let offer = OfferBuilder::new(pubkey(42))
1225                         .chain(Network::Testnet)
1226                         .chain(Network::Testnet)
1227                         .build()
1228                         .unwrap();
1229                 assert!(offer.supports_chain(testnet));
1230                 assert_eq!(offer.chains(), vec![testnet]);
1231                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
1232
1233                 let offer = OfferBuilder::new(pubkey(42))
1234                         .chain(Network::Bitcoin)
1235                         .chain(Network::Testnet)
1236                         .build()
1237                         .unwrap();
1238                 assert!(offer.supports_chain(mainnet));
1239                 assert!(offer.supports_chain(testnet));
1240                 assert_eq!(offer.chains(), vec![mainnet, testnet]);
1241                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![mainnet, testnet]));
1242         }
1243
1244         #[test]
1245         fn builds_offer_with_metadata() {
1246                 let offer = OfferBuilder::new(pubkey(42))
1247                         .metadata(vec![42; 32]).unwrap()
1248                         .build()
1249                         .unwrap();
1250                 assert_eq!(offer.metadata(), Some(&vec![42; 32]));
1251                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![42; 32]));
1252
1253                 let offer = OfferBuilder::new(pubkey(42))
1254                         .metadata(vec![42; 32]).unwrap()
1255                         .metadata(vec![43; 32]).unwrap()
1256                         .build()
1257                         .unwrap();
1258                 assert_eq!(offer.metadata(), Some(&vec![43; 32]));
1259                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![43; 32]));
1260         }
1261
1262         #[test]
1263         fn builds_offer_with_metadata_derived() {
1264                 let node_id = recipient_pubkey();
1265                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1266                 let entropy = FixedEntropy {};
1267                 let secp_ctx = Secp256k1::new();
1268
1269                 #[cfg(c_bindings)]
1270                 use super::OfferWithDerivedMetadataBuilder as OfferBuilder;
1271                 let offer = OfferBuilder
1272                         ::deriving_signing_pubkey(node_id, &expanded_key, &entropy, &secp_ctx)
1273                         .amount_msats(1000)
1274                         .build().unwrap();
1275                 assert_eq!(offer.signing_pubkey(), Some(node_id));
1276
1277                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1278                         .build().unwrap()
1279                         .sign(payer_sign).unwrap();
1280                 match invoice_request.verify(&expanded_key, &secp_ctx) {
1281                         Ok(invoice_request) => assert_eq!(invoice_request.offer_id, offer.id()),
1282                         Err(_) => panic!("unexpected error"),
1283                 }
1284
1285                 // Fails verification with altered offer field
1286                 let mut tlv_stream = offer.as_tlv_stream();
1287                 tlv_stream.amount = Some(100);
1288
1289                 let mut encoded_offer = Vec::new();
1290                 tlv_stream.write(&mut encoded_offer).unwrap();
1291
1292                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1293                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1294                         .build().unwrap()
1295                         .sign(payer_sign).unwrap();
1296                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1297
1298                 // Fails verification with altered metadata
1299                 let mut tlv_stream = offer.as_tlv_stream();
1300                 let metadata = tlv_stream.metadata.unwrap().iter().copied().rev().collect();
1301                 tlv_stream.metadata = Some(&metadata);
1302
1303                 let mut encoded_offer = Vec::new();
1304                 tlv_stream.write(&mut encoded_offer).unwrap();
1305
1306                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1307                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1308                         .build().unwrap()
1309                         .sign(payer_sign).unwrap();
1310                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1311         }
1312
1313         #[test]
1314         fn builds_offer_with_derived_signing_pubkey() {
1315                 let node_id = recipient_pubkey();
1316                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1317                 let entropy = FixedEntropy {};
1318                 let secp_ctx = Secp256k1::new();
1319
1320                 let blinded_path = BlindedPath {
1321                         introduction_node: IntroductionNode::NodeId(pubkey(40)),
1322                         blinding_point: pubkey(41),
1323                         blinded_hops: vec![
1324                                 BlindedHop { blinded_node_id: pubkey(42), encrypted_payload: vec![0; 43] },
1325                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
1326                         ],
1327                 };
1328
1329                 #[cfg(c_bindings)]
1330                 use super::OfferWithDerivedMetadataBuilder as OfferBuilder;
1331                 let offer = OfferBuilder
1332                         ::deriving_signing_pubkey(node_id, &expanded_key, &entropy, &secp_ctx)
1333                         .amount_msats(1000)
1334                         .path(blinded_path)
1335                         .build().unwrap();
1336                 assert_ne!(offer.signing_pubkey(), Some(node_id));
1337
1338                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1339                         .build().unwrap()
1340                         .sign(payer_sign).unwrap();
1341                 match invoice_request.verify(&expanded_key, &secp_ctx) {
1342                         Ok(invoice_request) => assert_eq!(invoice_request.offer_id, offer.id()),
1343                         Err(_) => panic!("unexpected error"),
1344                 }
1345
1346                 // Fails verification with altered offer field
1347                 let mut tlv_stream = offer.as_tlv_stream();
1348                 tlv_stream.amount = Some(100);
1349
1350                 let mut encoded_offer = Vec::new();
1351                 tlv_stream.write(&mut encoded_offer).unwrap();
1352
1353                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1354                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1355                         .build().unwrap()
1356                         .sign(payer_sign).unwrap();
1357                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1358
1359                 // Fails verification with altered signing pubkey
1360                 let mut tlv_stream = offer.as_tlv_stream();
1361                 let signing_pubkey = pubkey(1);
1362                 tlv_stream.node_id = Some(&signing_pubkey);
1363
1364                 let mut encoded_offer = Vec::new();
1365                 tlv_stream.write(&mut encoded_offer).unwrap();
1366
1367                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1368                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1369                         .build().unwrap()
1370                         .sign(payer_sign).unwrap();
1371                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1372         }
1373
1374         #[test]
1375         fn builds_offer_with_amount() {
1376                 let bitcoin_amount = Amount::Bitcoin { amount_msats: 1000 };
1377                 let currency_amount = Amount::Currency { iso4217_code: *b"USD", amount: 10 };
1378
1379                 let offer = OfferBuilder::new(pubkey(42))
1380                         .amount_msats(1000)
1381                         .build()
1382                         .unwrap();
1383                 let tlv_stream = offer.as_tlv_stream();
1384                 assert_eq!(offer.amount(), Some(&bitcoin_amount));
1385                 assert_eq!(tlv_stream.amount, Some(1000));
1386                 assert_eq!(tlv_stream.currency, None);
1387
1388                 #[cfg(not(c_bindings))]
1389                 let builder = OfferBuilder::new(pubkey(42))
1390                         .amount(currency_amount.clone());
1391                 #[cfg(c_bindings)]
1392                 let mut builder = OfferBuilder::new(pubkey(42));
1393                 #[cfg(c_bindings)]
1394                 builder.amount(currency_amount.clone());
1395                 let tlv_stream = builder.offer.as_tlv_stream();
1396                 assert_eq!(builder.offer.amount, Some(currency_amount.clone()));
1397                 assert_eq!(tlv_stream.amount, Some(10));
1398                 assert_eq!(tlv_stream.currency, Some(b"USD"));
1399                 match builder.build() {
1400                         Ok(_) => panic!("expected error"),
1401                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnsupportedCurrency),
1402                 }
1403
1404                 let offer = OfferBuilder::new(pubkey(42))
1405                         .amount(currency_amount.clone())
1406                         .amount(bitcoin_amount.clone())
1407                         .build()
1408                         .unwrap();
1409                 let tlv_stream = offer.as_tlv_stream();
1410                 assert_eq!(tlv_stream.amount, Some(1000));
1411                 assert_eq!(tlv_stream.currency, None);
1412
1413                 let invalid_amount = Amount::Bitcoin { amount_msats: MAX_VALUE_MSAT + 1 };
1414                 match OfferBuilder::new(pubkey(42)).amount(invalid_amount).build() {
1415                         Ok(_) => panic!("expected error"),
1416                         Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
1417                 }
1418         }
1419
1420         #[test]
1421         fn builds_offer_with_description() {
1422                 let offer = OfferBuilder::new(pubkey(42))
1423                         .description("foo".into())
1424                         .build()
1425                         .unwrap();
1426                 assert_eq!(offer.description(), Some(PrintableString("foo")));
1427                 assert_eq!(offer.as_tlv_stream().description, Some(&String::from("foo")));
1428
1429                 let offer = OfferBuilder::new(pubkey(42))
1430                         .description("foo".into())
1431                         .description("bar".into())
1432                         .build()
1433                         .unwrap();
1434                 assert_eq!(offer.description(), Some(PrintableString("bar")));
1435                 assert_eq!(offer.as_tlv_stream().description, Some(&String::from("bar")));
1436
1437                 let offer = OfferBuilder::new(pubkey(42))
1438                         .amount_msats(1000)
1439                         .build()
1440                         .unwrap();
1441                 assert_eq!(offer.description(), Some(PrintableString("")));
1442                 assert_eq!(offer.as_tlv_stream().description, Some(&String::from("")));
1443         }
1444
1445         #[test]
1446         fn builds_offer_with_features() {
1447                 let offer = OfferBuilder::new(pubkey(42))
1448                         .features_unchecked(OfferFeatures::unknown())
1449                         .build()
1450                         .unwrap();
1451                 assert_eq!(offer.offer_features(), &OfferFeatures::unknown());
1452                 assert_eq!(offer.as_tlv_stream().features, Some(&OfferFeatures::unknown()));
1453
1454                 let offer = OfferBuilder::new(pubkey(42))
1455                         .features_unchecked(OfferFeatures::unknown())
1456                         .features_unchecked(OfferFeatures::empty())
1457                         .build()
1458                         .unwrap();
1459                 assert_eq!(offer.offer_features(), &OfferFeatures::empty());
1460                 assert_eq!(offer.as_tlv_stream().features, None);
1461         }
1462
1463         #[test]
1464         fn builds_offer_with_absolute_expiry() {
1465                 let future_expiry = Duration::from_secs(u64::max_value());
1466                 let past_expiry = Duration::from_secs(0);
1467                 let now = future_expiry - Duration::from_secs(1_000);
1468
1469                 let offer = OfferBuilder::new(pubkey(42))
1470                         .absolute_expiry(future_expiry)
1471                         .build()
1472                         .unwrap();
1473                 #[cfg(feature = "std")]
1474                 assert!(!offer.is_expired());
1475                 assert!(!offer.is_expired_no_std(now));
1476                 assert_eq!(offer.absolute_expiry(), Some(future_expiry));
1477                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(future_expiry.as_secs()));
1478
1479                 let offer = OfferBuilder::new(pubkey(42))
1480                         .absolute_expiry(future_expiry)
1481                         .absolute_expiry(past_expiry)
1482                         .build()
1483                         .unwrap();
1484                 #[cfg(feature = "std")]
1485                 assert!(offer.is_expired());
1486                 assert!(offer.is_expired_no_std(now));
1487                 assert_eq!(offer.absolute_expiry(), Some(past_expiry));
1488                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(past_expiry.as_secs()));
1489         }
1490
1491         #[test]
1492         fn builds_offer_with_paths() {
1493                 let paths = vec![
1494                         BlindedPath {
1495                                 introduction_node: IntroductionNode::NodeId(pubkey(40)),
1496                                 blinding_point: pubkey(41),
1497                                 blinded_hops: vec![
1498                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1499                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1500                                 ],
1501                         },
1502                         BlindedPath {
1503                                 introduction_node: IntroductionNode::NodeId(pubkey(40)),
1504                                 blinding_point: pubkey(41),
1505                                 blinded_hops: vec![
1506                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1507                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1508                                 ],
1509                         },
1510                 ];
1511
1512                 let offer = OfferBuilder::new(pubkey(42))
1513                         .path(paths[0].clone())
1514                         .path(paths[1].clone())
1515                         .build()
1516                         .unwrap();
1517                 let tlv_stream = offer.as_tlv_stream();
1518                 assert_eq!(offer.paths(), paths.as_slice());
1519                 assert_eq!(offer.signing_pubkey(), Some(pubkey(42)));
1520                 assert_ne!(pubkey(42), pubkey(44));
1521                 assert_eq!(tlv_stream.paths, Some(&paths));
1522                 assert_eq!(tlv_stream.node_id, Some(&pubkey(42)));
1523         }
1524
1525         #[test]
1526         fn builds_offer_with_issuer() {
1527                 let offer = OfferBuilder::new(pubkey(42))
1528                         .issuer("foo".into())
1529                         .build()
1530                         .unwrap();
1531                 assert_eq!(offer.issuer(), Some(PrintableString("foo")));
1532                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("foo")));
1533
1534                 let offer = OfferBuilder::new(pubkey(42))
1535                         .issuer("foo".into())
1536                         .issuer("bar".into())
1537                         .build()
1538                         .unwrap();
1539                 assert_eq!(offer.issuer(), Some(PrintableString("bar")));
1540                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("bar")));
1541         }
1542
1543         #[test]
1544         fn builds_offer_with_supported_quantity() {
1545                 let one = NonZeroU64::new(1).unwrap();
1546                 let ten = NonZeroU64::new(10).unwrap();
1547
1548                 let offer = OfferBuilder::new(pubkey(42))
1549                         .supported_quantity(Quantity::One)
1550                         .build()
1551                         .unwrap();
1552                 let tlv_stream = offer.as_tlv_stream();
1553                 assert_eq!(offer.supported_quantity(), Quantity::One);
1554                 assert_eq!(tlv_stream.quantity_max, None);
1555
1556                 let offer = OfferBuilder::new(pubkey(42))
1557                         .supported_quantity(Quantity::Unbounded)
1558                         .build()
1559                         .unwrap();
1560                 let tlv_stream = offer.as_tlv_stream();
1561                 assert_eq!(offer.supported_quantity(), Quantity::Unbounded);
1562                 assert_eq!(tlv_stream.quantity_max, Some(0));
1563
1564                 let offer = OfferBuilder::new(pubkey(42))
1565                         .supported_quantity(Quantity::Bounded(ten))
1566                         .build()
1567                         .unwrap();
1568                 let tlv_stream = offer.as_tlv_stream();
1569                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(ten));
1570                 assert_eq!(tlv_stream.quantity_max, Some(10));
1571
1572                 let offer = OfferBuilder::new(pubkey(42))
1573                         .supported_quantity(Quantity::Bounded(one))
1574                         .build()
1575                         .unwrap();
1576                 let tlv_stream = offer.as_tlv_stream();
1577                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(one));
1578                 assert_eq!(tlv_stream.quantity_max, Some(1));
1579
1580                 let offer = OfferBuilder::new(pubkey(42))
1581                         .supported_quantity(Quantity::Bounded(ten))
1582                         .supported_quantity(Quantity::One)
1583                         .build()
1584                         .unwrap();
1585                 let tlv_stream = offer.as_tlv_stream();
1586                 assert_eq!(offer.supported_quantity(), Quantity::One);
1587                 assert_eq!(tlv_stream.quantity_max, None);
1588         }
1589
1590         #[test]
1591         fn fails_requesting_invoice_with_unknown_required_features() {
1592                 match OfferBuilder::new(pubkey(42))
1593                         .features_unchecked(OfferFeatures::unknown())
1594                         .build().unwrap()
1595                         .request_invoice(vec![1; 32], pubkey(43))
1596                 {
1597                         Ok(_) => panic!("expected error"),
1598                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnknownRequiredFeatures),
1599                 }
1600         }
1601
1602         #[test]
1603         fn parses_offer_with_chains() {
1604                 let offer = OfferBuilder::new(pubkey(42))
1605                         .chain(Network::Bitcoin)
1606                         .chain(Network::Testnet)
1607                         .build()
1608                         .unwrap();
1609                 if let Err(e) = offer.to_string().parse::<Offer>() {
1610                         panic!("error parsing offer: {:?}", e);
1611                 }
1612         }
1613
1614         #[test]
1615         fn parses_offer_with_amount() {
1616                 let offer = OfferBuilder::new(pubkey(42))
1617                         .amount(Amount::Bitcoin { amount_msats: 1000 })
1618                         .build()
1619                         .unwrap();
1620                 if let Err(e) = offer.to_string().parse::<Offer>() {
1621                         panic!("error parsing offer: {:?}", e);
1622                 }
1623
1624                 let mut tlv_stream = offer.as_tlv_stream();
1625                 tlv_stream.amount = Some(1000);
1626                 tlv_stream.currency = Some(b"USD");
1627
1628                 let mut encoded_offer = Vec::new();
1629                 tlv_stream.write(&mut encoded_offer).unwrap();
1630
1631                 if let Err(e) = Offer::try_from(encoded_offer) {
1632                         panic!("error parsing offer: {:?}", e);
1633                 }
1634
1635                 let mut tlv_stream = offer.as_tlv_stream();
1636                 tlv_stream.amount = None;
1637                 tlv_stream.currency = Some(b"USD");
1638
1639                 let mut encoded_offer = Vec::new();
1640                 tlv_stream.write(&mut encoded_offer).unwrap();
1641
1642                 match Offer::try_from(encoded_offer) {
1643                         Ok(_) => panic!("expected error"),
1644                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingAmount)),
1645                 }
1646
1647                 let mut tlv_stream = offer.as_tlv_stream();
1648                 tlv_stream.amount = Some(MAX_VALUE_MSAT + 1);
1649                 tlv_stream.currency = None;
1650
1651                 let mut encoded_offer = Vec::new();
1652                 tlv_stream.write(&mut encoded_offer).unwrap();
1653
1654                 match Offer::try_from(encoded_offer) {
1655                         Ok(_) => panic!("expected error"),
1656                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InvalidAmount)),
1657                 }
1658         }
1659
1660         #[test]
1661         fn parses_offer_with_description() {
1662                 let offer = OfferBuilder::new(pubkey(42)).build().unwrap();
1663                 if let Err(e) = offer.to_string().parse::<Offer>() {
1664                         panic!("error parsing offer: {:?}", e);
1665                 }
1666
1667                 let offer = OfferBuilder::new(pubkey(42))
1668                         .description("foo".to_string())
1669                         .amount_msats(1000)
1670                         .build().unwrap();
1671                 if let Err(e) = offer.to_string().parse::<Offer>() {
1672                         panic!("error parsing offer: {:?}", e);
1673                 }
1674
1675                 let mut tlv_stream = offer.as_tlv_stream();
1676                 tlv_stream.description = None;
1677
1678                 let mut encoded_offer = Vec::new();
1679                 tlv_stream.write(&mut encoded_offer).unwrap();
1680
1681                 match Offer::try_from(encoded_offer) {
1682                         Ok(_) => panic!("expected error"),
1683                         Err(e) => {
1684                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription));
1685                         },
1686                 }
1687         }
1688
1689         #[test]
1690         fn parses_offer_with_paths() {
1691                 let offer = OfferBuilder::new(pubkey(42))
1692                         .path(BlindedPath {
1693                                 introduction_node: IntroductionNode::NodeId(pubkey(40)),
1694                                 blinding_point: pubkey(41),
1695                                 blinded_hops: vec![
1696                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1697                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1698                                 ],
1699                         })
1700                         .path(BlindedPath {
1701                                 introduction_node: IntroductionNode::NodeId(pubkey(40)),
1702                                 blinding_point: pubkey(41),
1703                                 blinded_hops: vec![
1704                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1705                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1706                                 ],
1707                         })
1708                         .build()
1709                         .unwrap();
1710                 if let Err(e) = offer.to_string().parse::<Offer>() {
1711                         panic!("error parsing offer: {:?}", e);
1712                 }
1713
1714                 let offer = OfferBuilder::new(pubkey(42))
1715                         .path(BlindedPath {
1716                                 introduction_node: IntroductionNode::NodeId(pubkey(40)),
1717                                 blinding_point: pubkey(41),
1718                                 blinded_hops: vec![
1719                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1720                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1721                                 ],
1722                         })
1723                         .clear_signing_pubkey()
1724                         .build()
1725                         .unwrap();
1726                 if let Err(e) = offer.to_string().parse::<Offer>() {
1727                         panic!("error parsing offer: {:?}", e);
1728                 }
1729
1730                 let mut builder = OfferBuilder::new(pubkey(42));
1731                 builder.offer.paths = Some(vec![]);
1732
1733                 let offer = builder.build().unwrap();
1734                 match offer.to_string().parse::<Offer>() {
1735                         Ok(_) => panic!("expected error"),
1736                         Err(e) => {
1737                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingPaths));
1738                         },
1739                 }
1740         }
1741
1742         #[test]
1743         fn parses_offer_with_quantity() {
1744                 let offer = OfferBuilder::new(pubkey(42))
1745                         .supported_quantity(Quantity::One)
1746                         .build()
1747                         .unwrap();
1748                 if let Err(e) = offer.to_string().parse::<Offer>() {
1749                         panic!("error parsing offer: {:?}", e);
1750                 }
1751
1752                 let offer = OfferBuilder::new(pubkey(42))
1753                         .supported_quantity(Quantity::Unbounded)
1754                         .build()
1755                         .unwrap();
1756                 if let Err(e) = offer.to_string().parse::<Offer>() {
1757                         panic!("error parsing offer: {:?}", e);
1758                 }
1759
1760                 let offer = OfferBuilder::new(pubkey(42))
1761                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(10).unwrap()))
1762                         .build()
1763                         .unwrap();
1764                 if let Err(e) = offer.to_string().parse::<Offer>() {
1765                         panic!("error parsing offer: {:?}", e);
1766                 }
1767
1768                 let offer = OfferBuilder::new(pubkey(42))
1769                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(1).unwrap()))
1770                         .build()
1771                         .unwrap();
1772                 if let Err(e) = offer.to_string().parse::<Offer>() {
1773                         panic!("error parsing offer: {:?}", e);
1774                 }
1775         }
1776
1777         #[test]
1778         fn parses_offer_with_node_id() {
1779                 let offer = OfferBuilder::new(pubkey(42)).build().unwrap();
1780                 if let Err(e) = offer.to_string().parse::<Offer>() {
1781                         panic!("error parsing offer: {:?}", e);
1782                 }
1783
1784                 let mut tlv_stream = offer.as_tlv_stream();
1785                 tlv_stream.node_id = None;
1786
1787                 let mut encoded_offer = Vec::new();
1788                 tlv_stream.write(&mut encoded_offer).unwrap();
1789
1790                 match Offer::try_from(encoded_offer) {
1791                         Ok(_) => panic!("expected error"),
1792                         Err(e) => {
1793                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingSigningPubkey));
1794                         },
1795                 }
1796         }
1797
1798         #[test]
1799         fn fails_parsing_offer_with_extra_tlv_records() {
1800                 let offer = OfferBuilder::new(pubkey(42)).build().unwrap();
1801
1802                 let mut encoded_offer = Vec::new();
1803                 offer.write(&mut encoded_offer).unwrap();
1804                 BigSize(80).write(&mut encoded_offer).unwrap();
1805                 BigSize(32).write(&mut encoded_offer).unwrap();
1806                 [42u8; 32].write(&mut encoded_offer).unwrap();
1807
1808                 match Offer::try_from(encoded_offer) {
1809                         Ok(_) => panic!("expected error"),
1810                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1811                 }
1812         }
1813 }
1814
1815 #[cfg(test)]
1816 mod bolt12_tests {
1817         use super::{Bolt12ParseError, Bolt12SemanticError, Offer};
1818         use crate::ln::msgs::DecodeError;
1819
1820         #[test]
1821         fn parses_bech32_encoded_offers() {
1822                 let offers = [
1823                         // Minimal bolt12 offer
1824                         "lno1pgx9getnwss8vetrw3hhyuckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1825
1826                         // for testnet
1827                         "lno1qgsyxjtl6luzd9t3pr62xr7eemp6awnejusgf6gw45q75vcfqqqqqqq2p32x2um5ypmx2cm5dae8x93pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpj",
1828
1829                         // for bitcoin (redundant)
1830                         "lno1qgsxlc5vp2m0rvmjcxn2y34wv0m5lyc7sdj7zksgn35dvxgqqqqqqqq2p32x2um5ypmx2cm5dae8x93pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpj",
1831
1832                         // for bitcoin or liquidv1
1833                         "lno1qfqpge38tqmzyrdjj3x2qkdr5y80dlfw56ztq6yd9sme995g3gsxqqm0u2xq4dh3kdevrf4zg6hx8a60jv0gxe0ptgyfc6xkryqqqqqqqq9qc4r9wd6zqan9vd6x7unnzcss9mk8y3wkklfvevcrszlmu23kfrxh49px20665dqwmn4p72pksese",
1834
1835                         // with metadata
1836                         "lno1qsgqqqqqqqqqqqqqqqqqqqqqqqqqqzsv23jhxapqwejkxar0wfe3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1837
1838                         // with amount
1839                         "lno1pqpzwyq2p32x2um5ypmx2cm5dae8x93pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpj",
1840
1841                         // with currency
1842                         "lno1qcp4256ypqpzwyq2p32x2um5ypmx2cm5dae8x93pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpj",
1843
1844                         // with expiry
1845                         "lno1pgx9getnwss8vetrw3hhyucwq3ay997czcss9mk8y3wkklfvevcrszlmu23kfrxh49px20665dqwmn4p72pksese",
1846
1847                         // with issuer
1848                         "lno1pgx9getnwss8vetrw3hhyucjy358garswvaz7tmzdak8gvfj9ehhyeeqgf85c4p3xgsxjmnyw4ehgunfv4e3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1849
1850                         // with quantity
1851                         "lno1pgx9getnwss8vetrw3hhyuc5qyz3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1852
1853                         // with unlimited (or unknown) quantity
1854                         "lno1pgx9getnwss8vetrw3hhyuc5qqtzzqhwcuj966ma9n9nqwqtl032xeyv6755yeflt235pmww58egx6rxry",
1855
1856                         // with single quantity (weird but valid)
1857                         "lno1pgx9getnwss8vetrw3hhyuc5qyq3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1858
1859                         // with feature
1860                         "lno1pgx9getnwss8vetrw3hhyucvp5yqqqqqqqqqqqqqqqqqqqqkyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1861
1862                         // with blinded path via Bob (0x424242...), blinding 020202...
1863                         "lno1pgx9getnwss8vetrw3hhyucs5ypjgef743p5fzqq9nqxh0ah7y87rzv3ud0eleps9kl2d5348hq2k8qzqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgqpqqqqqqqqqqqqqqqqqqqqqqqqqqqzqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqqzq3zyg3zyg3zyg3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1864
1865                         // ... and with second blinded path via Carol (0x434343...), blinding 020202...
1866                         "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",
1867
1868                         // unknown odd field
1869                         "lno1pgx9getnwss8vetrw3hhyuckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxfppf5x2mrvdamk7unvvs",
1870                 ];
1871                 for encoded_offer in &offers {
1872                         if let Err(e) = encoded_offer.parse::<Offer>() {
1873                                 panic!("Invalid offer ({:?}): {}", e, encoded_offer);
1874                         }
1875                 }
1876         }
1877
1878         #[test]
1879         fn fails_parsing_bech32_encoded_offers() {
1880                 // Malformed: fields out of order
1881                 assert_eq!(
1882                         "lno1zcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszpgz5znzfgdzs".parse::<Offer>(),
1883                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1884                 );
1885
1886                 // Malformed: unknown even TLV type 78
1887                 assert_eq!(
1888                         "lno1pgz5znzfgdz3vggzqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpysgr0u2xq4dh3kdevrf4zg6hx8a60jv0gxe0ptgyfc6xkryqqqqqqqq".parse::<Offer>(),
1889                         Err(Bolt12ParseError::Decode(DecodeError::UnknownRequiredFeature)),
1890                 );
1891
1892                 // Malformed: empty
1893                 assert_eq!(
1894                         "lno1".parse::<Offer>(),
1895                         Err(Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingSigningPubkey)),
1896                 );
1897
1898                 // Malformed: truncated at type
1899                 assert_eq!(
1900                         "lno1pg".parse::<Offer>(),
1901                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1902                 );
1903
1904                 // Malformed: truncated in length
1905                 assert_eq!(
1906                         "lno1pt7s".parse::<Offer>(),
1907                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1908                 );
1909
1910                 // Malformed: truncated after length
1911                 assert_eq!(
1912                         "lno1pgpq".parse::<Offer>(),
1913                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1914                 );
1915
1916                 // Malformed: truncated in description
1917                 assert_eq!(
1918                         "lno1pgpyz".parse::<Offer>(),
1919                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1920                 );
1921
1922                 // Malformed: invalid offer_chains length
1923                 assert_eq!(
1924                         "lno1qgqszzs9g9xyjs69zcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1925                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1926                 );
1927
1928                 // Malformed: truncated currency UTF-8
1929                 assert_eq!(
1930                         "lno1qcqcqzs9g9xyjs69zcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1931                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1932                 );
1933
1934                 // Malformed: invalid currency UTF-8
1935                 assert_eq!(
1936                         "lno1qcpgqsg2q4q5cj2rg5tzzqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqg".parse::<Offer>(),
1937                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1938                 );
1939
1940                 // Malformed: truncated description UTF-8
1941                 assert_eq!(
1942                         "lno1pgqcq93pqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqy".parse::<Offer>(),
1943                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1944                 );
1945
1946                 // Malformed: invalid description UTF-8
1947                 assert_eq!(
1948                         "lno1pgpgqsgkyypqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqs".parse::<Offer>(),
1949                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1950                 );
1951
1952                 // Malformed: truncated offer_paths
1953                 assert_eq!(
1954                         "lno1pgz5znzfgdz3qqgpzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1955                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1956                 );
1957
1958                 // Malformed: zero num_hops in blinded_path
1959                 assert_eq!(
1960                         "lno1pgz5znzfgdz3qqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1961                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1962                 );
1963
1964                 // Malformed: truncated onionmsg_hop in blinded_path
1965                 assert_eq!(
1966                         "lno1pgz5znzfgdz3qqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqspqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqgkyypqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqs".parse::<Offer>(),
1967                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1968                 );
1969
1970                 // Malformed: bad first_node_id in blinded_path
1971                 assert_eq!(
1972                         "lno1pgz5znzfgdz3qqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqspqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqgqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1973                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1974                 );
1975
1976                 // Malformed: bad blinding in blinded_path
1977                 assert_eq!(
1978                         "lno1pgz5znzfgdz3qqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcpqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqgqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1979                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1980                 );
1981
1982                 // Malformed: bad blinded_node_id in onionmsg_hop
1983                 assert_eq!(
1984                         "lno1pgz5znzfgdz3qqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqspqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqgqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1985                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1986                 );
1987
1988                 // Malformed: truncated issuer UTF-8
1989                 assert_eq!(
1990                         "lno1pgz5znzfgdz3yqvqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1991                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1992                 );
1993
1994                 // Malformed: invalid issuer UTF-8
1995                 assert_eq!(
1996                         "lno1pgz5znzfgdz3yq5qgytzzqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqg".parse::<Offer>(),
1997                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1998                 );
1999
2000                 // Malformed: invalid offer_node_id
2001                 assert_eq!(
2002                         "lno1pgz5znzfgdz3vggzqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvps".parse::<Offer>(),
2003                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
2004                 );
2005
2006                 // Contains type >= 80
2007                 assert_eq!(
2008                         "lno1pgz5znzfgdz3vggzqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgp9qgr0u2xq4dh3kdevrf4zg6hx8a60jv0gxe0ptgyfc6xkryqqqqqqqq".parse::<Offer>(),
2009                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
2010                 );
2011
2012                 // TODO: Resolved in spec https://github.com/lightning/bolts/pull/798/files#r1334851959
2013                 // Contains unknown feature 22
2014                 assert!(
2015                         "lno1pgx9getnwss8vetrw3hhyucvqdqqqqqkyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg".parse::<Offer>().is_ok()
2016                 );
2017
2018                 // Missing offer_description
2019                 assert_eq!(
2020                         // TODO: Match the spec once it is updated.
2021                         "lno1pqpq86qkyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg".parse::<Offer>(),
2022                         Err(Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription)),
2023                 );
2024
2025                 // Missing offer_node_id"
2026                 assert_eq!(
2027                         "lno1pgx9getnwss8vetrw3hhyuc".parse::<Offer>(),
2028                         Err(Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingSigningPubkey)),
2029                 );
2030         }
2031 }