_ Git - rust-lightning/blob - lightning/src/offers/offer.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! Data structures and encoding for `offer` messages.
  11 //!
  12 //! An [`Offer`] represents an "offer to be paid." It is typically constructed by a merchant and
  13 //! published as a QR code to be scanned by a customer. The customer uses the offer to request an
  14 //! invoice from the merchant to be paid.
  15 //!
  16 //! # Example
  17 //!
  18 //! ```
  19 //! extern crate bitcoin;
  20 //! extern crate core;
  21 //! extern crate lightning;
  22 //!
  23 //! use core::convert::TryFrom;
  24 //! use core::num::NonZeroU64;
  25 //! use core::time::Duration;
  26 //!
  27 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
  28 //! use lightning::offers::offer::{Offer, OfferBuilder, Quantity};
  29 //! use lightning::offers::parse::Bolt12ParseError;
  30 //! use lightning::util::ser::{Readable, Writeable};
  31 //!
  32 //! # use lightning::blinded_path::BlindedPath;
  33 //! # #[cfg(feature = "std")]
  34 //! # use std::time::SystemTime;
  35 //! #
  36 //! # fn create_blinded_path() -> BlindedPath { unimplemented!() }
  37 //! # fn create_another_blinded_path() -> BlindedPath { unimplemented!() }
  38 //! #
  39 //! # #[cfg(feature = "std")]
  40 //! # fn build() -> Result<(), Bolt12ParseError> {
  41 //! let secp_ctx = Secp256k1::new();
  42 //! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
  43 //! let pubkey = PublicKey::from(keys);
  44 //!
  45 //! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
  46 //! let offer = OfferBuilder::new("coffee, large".to_string(), pubkey)
  47 //!     .amount_msats(20_000)
  48 //!     .supported_quantity(Quantity::Unbounded)
  49 //!     .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
  50 //!     .issuer("Foo Bar".to_string())
  51 //!     .path(create_blinded_path())
  52 //!     .path(create_another_blinded_path())
  53 //!     .build()?;
  54 //!
  55 //! // Encode as a bech32 string for use in a QR code.
  56 //! let encoded_offer = offer.to_string();
  57 //!
  58 //! // Parse from a bech32 string after scanning from a QR code.
  59 //! let offer = encoded_offer.parse::<Offer>()?;
  60 //!
  61 //! // Encode offer as raw bytes.
  62 //! let mut bytes = Vec::new();
  63 //! offer.write(&mut bytes).unwrap();
  64 //!
  65 //! // Decode raw bytes into an offer.
  66 //! let offer = Offer::try_from(bytes)?;
  67 //! # Ok(())
  68 //! # }
  69 //! ```
  70 //!
  71 //! # Note
  72 //!
  73 //! If constructing an [`Offer`] for use with a [`ChannelManager`], use
  74 //! [`ChannelManager::create_offer_builder`] instead of [`OfferBuilder::new`].
  75 //!
  76 //! [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
  77 //! [`ChannelManager::create_offer_builder`]: crate::ln::channelmanager::ChannelManager::create_offer_builder
  78
  79 use bitcoin::blockdata::constants::ChainHash;
  80 use bitcoin::network::constants::Network;
  81 use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, self};
  82 use core::hash::{Hash, Hasher};
  83 use core::num::NonZeroU64;
  84 use core::ops::Deref;
  85 use core::str::FromStr;
  86 use core::time::Duration;
  87 use crate::sign::EntropySource;
  88 use crate::io;
  89 use crate::blinded_path::BlindedPath;
  90 use crate::ln::channelmanager::PaymentId;
  91 use crate::ln::features::OfferFeatures;
  92 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
  93 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
  94 use crate::offers::merkle::{TaggedHash, TlvStream};
  95 use crate::offers::parse::{Bech32Encode, Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
  96 use crate::offers::signer::{Metadata, MetadataMaterial, self};
  97 use crate::util::ser::{HighZeroBytesDroppedBigSize, Readable, WithoutLength, Writeable, Writer};
  98 use crate::util::string::PrintableString;
  99
 100 #[cfg(not(c_bindings))]
 101 use {
 102         crate::offers::invoice_request::{DerivedPayerId, ExplicitPayerId, InvoiceRequestBuilder},
 103 };
 104 #[cfg(c_bindings)]
 105 use {
 106         crate::offers::invoice_request::{InvoiceRequestWithDerivedPayerIdBuilder, InvoiceRequestWithExplicitPayerIdBuilder},
 107 };
 108
 109 #[allow(unused_imports)]
 110 use crate::prelude::*;
 111
 112 #[cfg(feature = "std")]
 113 use std::time::SystemTime;
 114
 115 pub(super) const IV_BYTES: &[u8; IV_LEN] = b"LDK Offer ~~~~~~";
 116
 117 /// An identifier for an [`Offer`] built using [`DerivedMetadata`].
 118 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 119 pub struct OfferId(pub [u8; 32]);
 120
 121 impl OfferId {
 122         const ID_TAG: &'static str = "LDK Offer ID";
 123
 124         fn from_valid_offer_tlv_stream(bytes: &[u8]) -> Self {
 125                 let tagged_hash = TaggedHash::from_valid_tlv_stream_bytes(Self::ID_TAG, bytes);
 126                 Self(tagged_hash.to_bytes())
 127         }
 128
 129         fn from_valid_invreq_tlv_stream(bytes: &[u8]) -> Self {
 130                 let tlv_stream = TlvStream::new(bytes).range(OFFER_TYPES);
 131                 let tagged_hash = TaggedHash::from_tlv_stream(Self::ID_TAG, tlv_stream);
 132                 Self(tagged_hash.to_bytes())
 133         }
 134 }
 135
 136 impl Writeable for OfferId {
 137         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 138                 self.0.write(w)
 139         }
 140 }
 141
 142 impl Readable for OfferId {
 143         fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
 144                 Ok(OfferId(Readable::read(r)?))
 145         }
 146 }
 147
 148 /// Builds an [`Offer`] for the "offer to be paid" flow.
 149 ///
 150 /// See [module-level documentation] for usage.
 151 ///
 152 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 153 ///
 154 /// [module-level documentation]: self
 155 pub struct OfferBuilder<'a, M: MetadataStrategy, T: secp256k1::Signing> {
 156         offer: OfferContents,
 157         metadata_strategy: core::marker::PhantomData<M>,
 158         secp_ctx: Option<&'a Secp256k1<T>>,
 159 }
 160
 161 /// Builds an [`Offer`] for the "offer to be paid" flow.
 162 ///
 163 /// See [module-level documentation] for usage.
 164 ///
 165 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 166 ///
 167 /// [module-level documentation]: self
 168 #[cfg(c_bindings)]
 169 pub struct OfferWithExplicitMetadataBuilder<'a> {
 170         offer: OfferContents,
 171         metadata_strategy: core::marker::PhantomData<ExplicitMetadata>,
 172         secp_ctx: Option<&'a Secp256k1<secp256k1::All>>,
 173 }
 174
 175 /// Builds an [`Offer`] for the "offer to be paid" flow.
 176 ///
 177 /// See [module-level documentation] for usage.
 178 ///
 179 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 180 ///
 181 /// [module-level documentation]: self
 182 #[cfg(c_bindings)]
 183 pub struct OfferWithDerivedMetadataBuilder<'a> {
 184         offer: OfferContents,
 185         metadata_strategy: core::marker::PhantomData<DerivedMetadata>,
 186         secp_ctx: Option<&'a Secp256k1<secp256k1::All>>,
 187 }
 188
 189 /// Indicates how [`Offer::metadata`] may be set.
 190 ///
 191 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 192 pub trait MetadataStrategy {}
 193
 194 /// [`Offer::metadata`] may be explicitly set or left empty.
 195 ///
 196 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 197 pub struct ExplicitMetadata {}
 198
 199 /// [`Offer::metadata`] will be derived.
 200 ///
 201 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 202 pub struct DerivedMetadata {}
 203
 204 impl MetadataStrategy for ExplicitMetadata {}
 205
 206 impl MetadataStrategy for DerivedMetadata {}
 207
 208 macro_rules! offer_explicit_metadata_builder_methods { (
 209         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr
 210 ) => {
 211         /// Creates a new builder for an offer setting the [`Offer::description`] and using the
 212         /// [`Offer::signing_pubkey`] for signing invoices. The associated secret key must be remembered
 213         /// 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(description: String, signing_pubkey: PublicKey) -> Self {
 225                 Self {
 226                         offer: OfferContents {
 227                                 chains: None, metadata: None, amount: None, description,
 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 { ($secp_context: ty) => {
 246         /// Similar to [`OfferBuilder::new`] except, if [`OfferBuilder::path`] is called, the signing
 247         /// pubkey is derived from the given [`ExpandedKey`] and [`EntropySource`]. This provides
 248         /// recipient privacy by using a different signing pubkey for each offer. Otherwise, the
 249         /// provided `node_id` is used for the signing pubkey.
 250         ///
 251         /// Also, sets the metadata when [`OfferBuilder::build`] is called such that it can be used by
 252         /// [`InvoiceRequest::verify`] to determine if the request was produced for the offer given an
 253         /// [`ExpandedKey`].
 254         ///
 255         /// [`InvoiceRequest::verify`]: crate::offers::invoice_request::InvoiceRequest::verify
 256         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 257         pub fn deriving_signing_pubkey<ES: Deref>(
 258                 description: String, node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 259                 secp_ctx: &'a Secp256k1<$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,
 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                 $return_value
 326         }
 327
 328         /// Sets the [`Offer::issuer`].
 329         ///
 330         /// Successive calls to this method will override the previous setting.
 331         pub fn issuer($($self_mut)* $self: $self_type, issuer: String) -> $return_type {
 332                 $self.offer.issuer = Some(issuer);
 333                 $return_value
 334         }
 335
 336         /// Adds a blinded path to [`Offer::paths`]. Must include at least one path if only connected by
 337         /// private channels or if [`Offer::signing_pubkey`] is not a public node id.
 338         ///
 339         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 340         /// adding duplicate paths.
 341         pub fn path($($self_mut)* $self: $self_type, path: BlindedPath) -> $return_type {
 342                 $self.offer.paths.get_or_insert_with(Vec::new).push(path);
 343                 $return_value
 344         }
 345
 346         /// Sets the quantity of items for [`Offer::supported_quantity`]. If not called, defaults to
 347         /// [`Quantity::One`].
 348         ///
 349         /// Successive calls to this method will override the previous setting.
 350         pub fn supported_quantity($($self_mut)* $self: $self_type, quantity: Quantity) -> $return_type {
 351                 $self.offer.supported_quantity = quantity;
 352                 $return_value
 353         }
 354
 355         /// Builds an [`Offer`] from the builder's settings.
 356         pub fn build($($self_mut)* $self: $self_type) -> Result<Offer, Bolt12SemanticError> {
 357                 match $self.offer.amount {
 358                         Some(Amount::Bitcoin { amount_msats }) => {
 359                                 if amount_msats > MAX_VALUE_MSAT {
 360                                         return Err(Bolt12SemanticError::InvalidAmount);
 361                                 }
 362                         },
 363                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 364                         None => {},
 365                 }
 366
 367                 if let Some(chains) = &$self.offer.chains {
 368                         if chains.len() == 1 && chains[0] == $self.offer.implied_chain() {
 369                                 $self.offer.chains = None;
 370                         }
 371                 }
 372
 373                 Ok($self.build_without_checks())
 374         }
 375
 376         fn build_without_checks($($self_mut)* $self: $self_type) -> Offer {
 377                 // Create the metadata for stateless verification of an InvoiceRequest.
 378                 if let Some(mut metadata) = $self.offer.metadata.take() {
 379                         if metadata.has_derivation_material() {
 380                                 if $self.offer.paths.is_none() {
 381                                         metadata = metadata.without_keys();
 382                                 }
 383
 384                                 let mut tlv_stream = $self.offer.as_tlv_stream();
 385                                 debug_assert_eq!(tlv_stream.metadata, None);
 386                                 tlv_stream.metadata = None;
 387                                 if metadata.derives_recipient_keys() {
 388                                         tlv_stream.node_id = None;
 389                                 }
 390
 391                                 let (derived_metadata, keys) = metadata.derive_from(tlv_stream, $self.secp_ctx);
 392                                 metadata = derived_metadata;
 393                                 if let Some(keys) = keys {
 394                                         $self.offer.signing_pubkey = Some(keys.public_key());
 395                                 }
 396                         }
 397
 398                         $self.offer.metadata = Some(metadata);
 399                 }
 400
 401                 let mut bytes = Vec::new();
 402                 $self.offer.write(&mut bytes).unwrap();
 403
 404                 let id = OfferId::from_valid_offer_tlv_stream(&bytes);
 405
 406                 Offer {
 407                         bytes,
 408                         #[cfg(not(c_bindings))]
 409                         contents: $self.offer,
 410                         #[cfg(c_bindings)]
 411                         contents: $self.offer.clone(),
 412                         id,
 413                 }
 414         }
 415 } }
 416
 417 #[cfg(test)]
 418 macro_rules! offer_builder_test_methods { (
 419         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr $(, $self_mut: tt)?
 420 ) => {
 421         #[cfg_attr(c_bindings, allow(dead_code))]
 422         fn features_unchecked($($self_mut)* $self: $self_type, features: OfferFeatures) -> $return_type {
 423                 $self.offer.features = features;
 424                 $return_value
 425         }
 426
 427         #[cfg_attr(c_bindings, allow(dead_code))]
 428         pub(crate) fn clear_chains($($self_mut)* $self: $self_type) -> $return_type {
 429                 $self.offer.chains = None;
 430                 $return_value
 431         }
 432
 433         #[cfg_attr(c_bindings, allow(dead_code))]
 434         pub(crate) fn clear_paths($($self_mut)* $self: $self_type) -> $return_type {
 435                 $self.offer.paths = None;
 436                 $return_value
 437         }
 438
 439         #[cfg_attr(c_bindings, allow(dead_code))]
 440         pub(super) fn build_unchecked($self: $self_type) -> Offer {
 441                 $self.build_without_checks()
 442         }
 443 } }
 444
 445 impl<'a, M: MetadataStrategy, T: secp256k1::Signing> OfferBuilder<'a, M, T> {
 446         offer_builder_methods!(self, Self, Self, self, mut);
 447
 448         #[cfg(test)]
 449         offer_builder_test_methods!(self, Self, Self, self, mut);
 450 }
 451
 452 impl<'a> OfferBuilder<'a, ExplicitMetadata, secp256k1::SignOnly> {
 453         offer_explicit_metadata_builder_methods!(self, Self, Self, self);
 454 }
 455
 456 impl<'a, T: secp256k1::Signing> OfferBuilder<'a, DerivedMetadata, T> {
 457         offer_derived_metadata_builder_methods!(T);
 458 }
 459
 460 #[cfg(all(c_bindings, not(test)))]
 461 impl<'a> OfferWithExplicitMetadataBuilder<'a> {
 462         offer_explicit_metadata_builder_methods!(self, &mut Self, (), ());
 463         offer_builder_methods!(self, &mut Self, (), ());
 464 }
 465
 466 #[cfg(all(c_bindings, test))]
 467 impl<'a> OfferWithExplicitMetadataBuilder<'a> {
 468         offer_explicit_metadata_builder_methods!(self, &mut Self, &mut Self, self);
 469         offer_builder_methods!(self, &mut Self, &mut Self, self);
 470         offer_builder_test_methods!(self, &mut Self, &mut Self, self);
 471 }
 472
 473 #[cfg(all(c_bindings, not(test)))]
 474 impl<'a> OfferWithDerivedMetadataBuilder<'a> {
 475         offer_derived_metadata_builder_methods!(secp256k1::All);
 476         offer_builder_methods!(self, &mut Self, (), ());
 477 }
 478
 479 #[cfg(all(c_bindings, test))]
 480 impl<'a> OfferWithDerivedMetadataBuilder<'a> {
 481         offer_derived_metadata_builder_methods!(secp256k1::All);
 482         offer_builder_methods!(self, &mut Self, &mut Self, self);
 483         offer_builder_test_methods!(self, &mut Self, &mut Self, self);
 484 }
 485
 486 #[cfg(c_bindings)]
 487 impl<'a> From<OfferBuilder<'a, DerivedMetadata, secp256k1::All>>
 488 for OfferWithDerivedMetadataBuilder<'a> {
 489         fn from(builder: OfferBuilder<'a, DerivedMetadata, secp256k1::All>) -> Self {
 490                 let OfferBuilder { offer, metadata_strategy, secp_ctx } = builder;
 491
 492                 Self { offer, metadata_strategy, secp_ctx }
 493         }
 494 }
 495
 496 #[cfg(c_bindings)]
 497 impl<'a> From<OfferWithDerivedMetadataBuilder<'a>>
 498 for OfferBuilder<'a, DerivedMetadata, secp256k1::All> {
 499         fn from(builder: OfferWithDerivedMetadataBuilder<'a>) -> Self {
 500                 let OfferWithDerivedMetadataBuilder { offer, metadata_strategy, secp_ctx } = builder;
 501
 502                 Self { offer, metadata_strategy, secp_ctx }
 503         }
 504 }
 505
 506 /// An `Offer` is a potentially long-lived proposal for payment of a good or service.
 507 ///
 508 /// An offer is a precursor to an [`InvoiceRequest`]. A merchant publishes an offer from which a
 509 /// customer may request an [`Bolt12Invoice`] for a specific quantity and using an amount sufficient
 510 /// to cover that quantity (i.e., at least `quantity * amount`). See [`Offer::amount`].
 511 ///
 512 /// Offers may be denominated in currency other than bitcoin but are ultimately paid using the
 513 /// latter.
 514 ///
 515 /// Through the use of [`BlindedPath`]s, offers provide recipient privacy.
 516 ///
 517 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 518 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 519 #[derive(Clone, Debug)]
 520 pub struct Offer {
 521         // The serialized offer. Needed when creating an `InvoiceRequest` if the offer contains unknown
 522         // fields.
 523         pub(super) bytes: Vec<u8>,
 524         pub(super) contents: OfferContents,
 525         id: OfferId,
 526 }
 527
 528 /// The contents of an [`Offer`], which may be shared with an [`InvoiceRequest`] or a
 529 /// [`Bolt12Invoice`].
 530 ///
 531 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 532 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 533 #[derive(Clone, Debug)]
 534 #[cfg_attr(test, derive(PartialEq))]
 535 pub(super) struct OfferContents {
 536         chains: Option<Vec<ChainHash>>,
 537         metadata: Option<Metadata>,
 538         amount: Option<Amount>,
 539         description: String,
 540         features: OfferFeatures,
 541         absolute_expiry: Option<Duration>,
 542         issuer: Option<String>,
 543         paths: Option<Vec<BlindedPath>>,
 544         supported_quantity: Quantity,
 545         signing_pubkey: Option<PublicKey>,
 546 }
 547
 548 macro_rules! offer_accessors { ($self: ident, $contents: expr) => {
 549         // TODO: Return a slice once ChainHash has constants.
 550         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1283
 551         // - https://github.com/rust-bitcoin/rust-bitcoin/pull/1286
 552         /// The chains that may be used when paying a requested invoice (e.g., bitcoin mainnet).
 553         /// Payments must be denominated in units of the minimal lightning-payable unit (e.g., msats)
 554         /// for the selected chain.
 555         pub fn chains(&$self) -> Vec<bitcoin::blockdata::constants::ChainHash> {
 556                 $contents.chains()
 557         }
 558
 559         // TODO: Link to corresponding method in `InvoiceRequest`.
 560         /// Opaque bytes set by the originator. Useful for authentication and validating fields since it
 561         /// is reflected in `invoice_request` messages along with all the other fields from the `offer`.
 562         pub fn metadata(&$self) -> Option<&Vec<u8>> {
 563                 $contents.metadata()
 564         }
 565
 566         /// The minimum amount required for a successful payment of a single item.
 567         pub fn amount(&$self) -> Option<&$crate::offers::offer::Amount> {
 568                 $contents.amount()
 569         }
 570
 571         /// A complete description of the purpose of the payment. Intended to be displayed to the user
 572         /// but with the caveat that it has not been verified in any way.
 573         pub fn description(&$self) -> $crate::util::string::PrintableString {
 574                 $contents.description()
 575         }
 576
 577         /// Features pertaining to the offer.
 578         pub fn offer_features(&$self) -> &$crate::ln::features::OfferFeatures {
 579                 &$contents.features()
 580         }
 581
 582         /// Duration since the Unix epoch when an invoice should no longer be requested.
 583         ///
 584         /// If `None`, the offer does not expire.
 585         pub fn absolute_expiry(&$self) -> Option<core::time::Duration> {
 586                 $contents.absolute_expiry()
 587         }
 588
 589         /// The issuer of the offer, possibly beginning with `user@domain` or `domain`. Intended to be
 590         /// displayed to the user but with the caveat that it has not been verified in any way.
 591         pub fn issuer(&$self) -> Option<$crate::util::string::PrintableString> {
 592                 $contents.issuer()
 593         }
 594
 595         /// Paths to the recipient originating from publicly reachable nodes. Blinded paths provide
 596         /// recipient privacy by obfuscating its node id.
 597         pub fn paths(&$self) -> &[$crate::blinded_path::BlindedPath] {
 598                 $contents.paths()
 599         }
 600
 601         /// The quantity of items supported.
 602         pub fn supported_quantity(&$self) -> $crate::offers::offer::Quantity {
 603                 $contents.supported_quantity()
 604         }
 605
 606         /// The public key used by the recipient to sign invoices.
 607         pub fn signing_pubkey(&$self) -> Option<bitcoin::secp256k1::PublicKey> {
 608                 $contents.signing_pubkey()
 609         }
 610 } }
 611
 612 impl Offer {
 613         offer_accessors!(self, self.contents);
 614
 615         /// Returns the id of the offer.
 616         pub fn id(&self) -> OfferId {
 617                 self.id
 618         }
 619
 620         pub(super) fn implied_chain(&self) -> ChainHash {
 621                 self.contents.implied_chain()
 622         }
 623
 624         /// Returns whether the given chain is supported by the offer.
 625         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 626                 self.contents.supports_chain(chain)
 627         }
 628
 629         /// Whether the offer has expired.
 630         #[cfg(feature = "std")]
 631         pub fn is_expired(&self) -> bool {
 632                 self.contents.is_expired()
 633         }
 634
 635         /// Whether the offer has expired given the duration since the Unix epoch.
 636         pub fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 637                 self.contents.is_expired_no_std(duration_since_epoch)
 638         }
 639
 640         /// Returns whether the given quantity is valid for the offer.
 641         pub fn is_valid_quantity(&self, quantity: u64) -> bool {
 642                 self.contents.is_valid_quantity(quantity)
 643         }
 644
 645         /// Returns whether a quantity is expected in an [`InvoiceRequest`] for the offer.
 646         ///
 647         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 648         pub fn expects_quantity(&self) -> bool {
 649                 self.contents.expects_quantity()
 650         }
 651 }
 652
 653 macro_rules! request_invoice_derived_payer_id { ($self: ident, $builder: ty) => {
 654         /// Similar to [`Offer::request_invoice`] except it:
 655         /// - derives the [`InvoiceRequest::payer_id`] such that a different key can be used for each
 656         ///   request,
 657         /// - sets [`InvoiceRequest::payer_metadata`] when [`InvoiceRequestBuilder::build`] is called
 658         ///   such that it can be used by [`Bolt12Invoice::verify`] to determine if the invoice was
 659         ///   requested using a base [`ExpandedKey`] from which the payer id was derived, and
 660         /// - includes the [`PaymentId`] encrypted in [`InvoiceRequest::payer_metadata`] so that it can
 661         ///   be used when sending the payment for the requested invoice.
 662         ///
 663         /// Useful to protect the sender's privacy.
 664         ///
 665         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 666         /// [`InvoiceRequest::payer_metadata`]: crate::offers::invoice_request::InvoiceRequest::payer_metadata
 667         /// [`Bolt12Invoice::verify`]: crate::offers::invoice::Bolt12Invoice::verify
 668         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 669         pub fn request_invoice_deriving_payer_id<
 670                 'a, 'b, ES: Deref,
 671                 #[cfg(not(c_bindings))]
 672                 T: secp256k1::Signing
 673         >(
 674                 &'a $self, expanded_key: &ExpandedKey, entropy_source: ES,
 675                 #[cfg(not(c_bindings))]
 676                 secp_ctx: &'b Secp256k1<T>,
 677                 #[cfg(c_bindings)]
 678                 secp_ctx: &'b Secp256k1<secp256k1::All>,
 679                 payment_id: PaymentId
 680         ) -> Result<$builder, Bolt12SemanticError>
 681         where
 682                 ES::Target: EntropySource,
 683         {
 684                 if $self.offer_features().requires_unknown_bits() {
 685                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 686                 }
 687
 688                 Ok(<$builder>::deriving_payer_id($self, expanded_key, entropy_source, secp_ctx, payment_id))
 689         }
 690 } }
 691
 692 macro_rules! request_invoice_explicit_payer_id { ($self: ident, $builder: ty) => {
 693         /// Similar to [`Offer::request_invoice_deriving_payer_id`] except uses `payer_id` for the
 694         /// [`InvoiceRequest::payer_id`] instead of deriving a different key for each request.
 695         ///
 696         /// Useful for recurring payments using the same `payer_id` with different invoices.
 697         ///
 698         /// [`InvoiceRequest::payer_id`]: crate::offers::invoice_request::InvoiceRequest::payer_id
 699         pub fn request_invoice_deriving_metadata<ES: Deref>(
 700                 &$self, payer_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 701                 payment_id: PaymentId
 702         ) -> Result<$builder, Bolt12SemanticError>
 703         where
 704                 ES::Target: EntropySource,
 705         {
 706                 if $self.offer_features().requires_unknown_bits() {
 707                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 708                 }
 709
 710                 Ok(<$builder>::deriving_metadata($self, payer_id, expanded_key, entropy_source, payment_id))
 711         }
 712
 713         /// Creates an [`InvoiceRequestBuilder`] for the offer with the given `metadata` and `payer_id`,
 714         /// which will be reflected in the `Bolt12Invoice` response.
 715         ///
 716         /// The `metadata` is useful for including information about the derivation of `payer_id` such
 717         /// that invoice response handling can be stateless. Also serves as payer-provided entropy while
 718         /// hashing in the signature calculation.
 719         ///
 720         /// This should not leak any information such as by using a simple BIP-32 derivation path.
 721         /// Otherwise, payments may be correlated.
 722         ///
 723         /// Errors if the offer contains unknown required features.
 724         ///
 725         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 726         pub fn request_invoice(
 727                 &$self, metadata: Vec<u8>, payer_id: PublicKey
 728         ) -> Result<$builder, Bolt12SemanticError> {
 729                 if $self.offer_features().requires_unknown_bits() {
 730                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 731                 }
 732
 733                 Ok(<$builder>::new($self, metadata, payer_id))
 734         }
 735 } }
 736
 737 #[cfg(not(c_bindings))]
 738 impl Offer {
 739         request_invoice_derived_payer_id!(self, InvoiceRequestBuilder<'a, 'b, DerivedPayerId, T>);
 740         request_invoice_explicit_payer_id!(self, InvoiceRequestBuilder<ExplicitPayerId, secp256k1::SignOnly>);
 741 }
 742
 743 #[cfg(c_bindings)]
 744 impl Offer {
 745         request_invoice_derived_payer_id!(self, InvoiceRequestWithDerivedPayerIdBuilder<'a, 'b>);
 746         request_invoice_explicit_payer_id!(self, InvoiceRequestWithExplicitPayerIdBuilder);
 747 }
 748
 749 #[cfg(test)]
 750 impl Offer {
 751         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 752                 self.contents.as_tlv_stream()
 753         }
 754 }
 755
 756 impl AsRef<[u8]> for Offer {
 757         fn as_ref(&self) -> &[u8] {
 758                 &self.bytes
 759         }
 760 }
 761
 762 impl PartialEq for Offer {
 763         fn eq(&self, other: &Self) -> bool {
 764                 self.bytes.eq(&other.bytes)
 765         }
 766 }
 767
 768 impl Eq for Offer {}
 769
 770 impl Hash for Offer {
 771         fn hash<H: Hasher>(&self, state: &mut H) {
 772                 self.bytes.hash(state);
 773         }
 774 }
 775
 776 impl OfferContents {
 777         pub fn chains(&self) -> Vec<ChainHash> {
 778                 self.chains.as_ref().cloned().unwrap_or_else(|| vec![self.implied_chain()])
 779         }
 780
 781         pub fn implied_chain(&self) -> ChainHash {
 782                 ChainHash::using_genesis_block(Network::Bitcoin)
 783         }
 784
 785         pub fn supports_chain(&self, chain: ChainHash) -> bool {
 786                 self.chains().contains(&chain)
 787         }
 788
 789         pub fn metadata(&self) -> Option<&Vec<u8>> {
 790                 self.metadata.as_ref().and_then(|metadata| metadata.as_bytes())
 791         }
 792
 793         pub fn amount(&self) -> Option<&Amount> {
 794                 self.amount.as_ref()
 795         }
 796
 797         pub fn description(&self) -> PrintableString {
 798                 PrintableString(&self.description)
 799         }
 800
 801         pub fn features(&self) -> &OfferFeatures {
 802                 &self.features
 803         }
 804
 805         pub fn absolute_expiry(&self) -> Option<Duration> {
 806                 self.absolute_expiry
 807         }
 808
 809         #[cfg(feature = "std")]
 810         pub(super) fn is_expired(&self) -> bool {
 811                 SystemTime::UNIX_EPOCH
 812                         .elapsed()
 813                         .map(|duration_since_epoch| self.is_expired_no_std(duration_since_epoch))
 814                         .unwrap_or(false)
 815         }
 816
 817         pub(super) fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 818                 self.absolute_expiry
 819                         .map(|absolute_expiry| duration_since_epoch > absolute_expiry)
 820                         .unwrap_or(false)
 821         }
 822
 823         pub fn issuer(&self) -> Option<PrintableString> {
 824                 self.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 825         }
 826
 827         pub fn paths(&self) -> &[BlindedPath] {
 828                 self.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 829         }
 830
 831         pub(super) fn check_amount_msats_for_quantity(
 832                 &self, amount_msats: Option<u64>, quantity: Option<u64>
 833         ) -> Result<(), Bolt12SemanticError> {
 834                 let offer_amount_msats = match self.amount {
 835                         None => 0,
 836                         Some(Amount::Bitcoin { amount_msats }) => amount_msats,
 837                         Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
 838                 };
 839
 840                 if !self.expects_quantity() || quantity.is_some() {
 841                         let expected_amount_msats = offer_amount_msats.checked_mul(quantity.unwrap_or(1))
 842                                 .ok_or(Bolt12SemanticError::InvalidAmount)?;
 843                         let amount_msats = amount_msats.unwrap_or(expected_amount_msats);
 844
 845                         if amount_msats < expected_amount_msats {
 846                                 return Err(Bolt12SemanticError::InsufficientAmount);
 847                         }
 848
 849                         if amount_msats > MAX_VALUE_MSAT {
 850                                 return Err(Bolt12SemanticError::InvalidAmount);
 851                         }
 852                 }
 853
 854                 Ok(())
 855         }
 856
 857         pub fn supported_quantity(&self) -> Quantity {
 858                 self.supported_quantity
 859         }
 860
 861         pub(super) fn check_quantity(&self, quantity: Option<u64>) -> Result<(), Bolt12SemanticError> {
 862                 let expects_quantity = self.expects_quantity();
 863                 match quantity {
 864                         None if expects_quantity => Err(Bolt12SemanticError::MissingQuantity),
 865                         Some(_) if !expects_quantity => Err(Bolt12SemanticError::UnexpectedQuantity),
 866                         Some(quantity) if !self.is_valid_quantity(quantity) => {
 867                                 Err(Bolt12SemanticError::InvalidQuantity)
 868                         },
 869                         _ => Ok(()),
 870                 }
 871         }
 872
 873         fn is_valid_quantity(&self, quantity: u64) -> bool {
 874                 match self.supported_quantity {
 875                         Quantity::Bounded(n) => quantity <= n.get(),
 876                         Quantity::Unbounded => quantity > 0,
 877                         Quantity::One => quantity == 1,
 878                 }
 879         }
 880
 881         fn expects_quantity(&self) -> bool {
 882                 match self.supported_quantity {
 883                         Quantity::Bounded(_) => true,
 884                         Quantity::Unbounded => true,
 885                         Quantity::One => false,
 886                 }
 887         }
 888
 889         pub(super) fn signing_pubkey(&self) -> Option<PublicKey> {
 890                 self.signing_pubkey
 891         }
 892
 893         /// Verifies that the offer metadata was produced from the offer in the TLV stream.
 894         pub(super) fn verify<T: secp256k1::Signing>(
 895                 &self, bytes: &[u8], key: &ExpandedKey, secp_ctx: &Secp256k1<T>
 896         ) -> Result<(OfferId, Option<KeyPair>), ()> {
 897                 match self.metadata() {
 898                         Some(metadata) => {
 899                                 let tlv_stream = TlvStream::new(bytes).range(OFFER_TYPES).filter(|record| {
 900                                         match record.r#type {
 901                                                 OFFER_METADATA_TYPE => false,
 902                                                 OFFER_NODE_ID_TYPE => {
 903                                                         !self.metadata.as_ref().unwrap().derives_recipient_keys()
 904                                                 },
 905                                                 _ => true,
 906                                         }
 907                                 });
 908                                 let signing_pubkey = match self.signing_pubkey() {
 909                                         Some(signing_pubkey) => signing_pubkey,
 910                                         None => return Err(()),
 911                                 };
 912                                 let keys = signer::verify_recipient_metadata(
 913                                         metadata, key, IV_BYTES, signing_pubkey, tlv_stream, secp_ctx
 914                                 )?;
 915
 916                                 let offer_id = OfferId::from_valid_invreq_tlv_stream(bytes);
 917
 918                                 Ok((offer_id, keys))
 919                         },
 920                         None => Err(()),
 921                 }
 922         }
 923
 924         pub(super) fn as_tlv_stream(&self) -> OfferTlvStreamRef {
 925                 let (currency, amount) = match &self.amount {
 926                         None => (None, None),
 927                         Some(Amount::Bitcoin { amount_msats }) => (None, Some(*amount_msats)),
 928                         Some(Amount::Currency { iso4217_code, amount }) => (
 929                                 Some(iso4217_code), Some(*amount)
 930                         ),
 931                 };
 932
 933                 let features = {
 934                         if self.features == OfferFeatures::empty() { None } else { Some(&self.features) }
 935                 };
 936
 937                 OfferTlvStreamRef {
 938                         chains: self.chains.as_ref(),
 939                         metadata: self.metadata(),
 940                         currency,
 941                         amount,
 942                         description: Some(&self.description),
 943                         features,
 944                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 945                         paths: self.paths.as_ref(),
 946                         issuer: self.issuer.as_ref(),
 947                         quantity_max: self.supported_quantity.to_tlv_record(),
 948                         node_id: self.signing_pubkey.as_ref(),
 949                 }
 950         }
 951 }
 952
 953 impl Writeable for Offer {
 954         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 955                 WithoutLength(&self.bytes).write(writer)
 956         }
 957 }
 958
 959 impl Writeable for OfferContents {
 960         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 961                 self.as_tlv_stream().write(writer)
 962         }
 963 }
 964
 965 /// The minimum amount required for an item in an [`Offer`], denominated in either bitcoin or
 966 /// another currency.
 967 #[derive(Clone, Debug, PartialEq)]
 968 pub enum Amount {
 969         /// An amount of bitcoin.
 970         Bitcoin {
 971                 /// The amount in millisatoshi.
 972                 amount_msats: u64,
 973         },
 974         /// An amount of currency specified using ISO 4712.
 975         Currency {
 976                 /// The currency that the amount is denominated in.
 977                 iso4217_code: CurrencyCode,
 978                 /// The amount in the currency unit adjusted by the ISO 4712 exponent (e.g., USD cents).
 979                 amount: u64,
 980         },
 981 }
 982
 983 /// An ISO 4712 three-letter currency code (e.g., USD).
 984 pub type CurrencyCode = [u8; 3];
 985
 986 /// Quantity of items supported by an [`Offer`].
 987 #[derive(Clone, Copy, Debug, PartialEq)]
 988 pub enum Quantity {
 989         /// Up to a specific number of items (inclusive). Use when more than one item can be requested
 990         /// but is limited (e.g., because of per customer or inventory limits).
 991         ///
 992         /// May be used with `NonZeroU64::new(1)` but prefer to use [`Quantity::One`] if only one item
 993         /// is supported.
 994         Bounded(NonZeroU64),
 995         /// One or more items. Use when more than one item can be requested without any limit.
 996         Unbounded,
 997         /// Only one item. Use when only a single item can be requested.
 998         One,
 999 }
1000
1001 impl Quantity {
1002         fn to_tlv_record(&self) -> Option<u64> {
1003                 match self {
1004                         Quantity::Bounded(n) => Some(n.get()),
1005                         Quantity::Unbounded => Some(0),
1006                         Quantity::One => None,
1007                 }
1008         }
1009 }
1010
1011 /// Valid type range for offer TLV records.
1012 pub(super) const OFFER_TYPES: core::ops::Range<u64> = 1..80;
1013
1014 /// TLV record type for [`Offer::metadata`].
1015 const OFFER_METADATA_TYPE: u64 = 4;
1016
1017 /// TLV record type for [`Offer::signing_pubkey`].
1018 const OFFER_NODE_ID_TYPE: u64 = 22;
1019
1020 tlv_stream!(OfferTlvStream, OfferTlvStreamRef, OFFER_TYPES, {
1021         (2, chains: (Vec<ChainHash>, WithoutLength)),
1022         (OFFER_METADATA_TYPE, metadata: (Vec<u8>, WithoutLength)),
1023         (6, currency: CurrencyCode),
1024         (8, amount: (u64, HighZeroBytesDroppedBigSize)),
1025         (10, description: (String, WithoutLength)),
1026         (12, features: (OfferFeatures, WithoutLength)),
1027         (14, absolute_expiry: (u64, HighZeroBytesDroppedBigSize)),
1028         (16, paths: (Vec<BlindedPath>, WithoutLength)),
1029         (18, issuer: (String, WithoutLength)),
1030         (20, quantity_max: (u64, HighZeroBytesDroppedBigSize)),
1031         (OFFER_NODE_ID_TYPE, node_id: PublicKey),
1032 });
1033
1034 impl Bech32Encode for Offer {
1035         const BECH32_HRP: &'static str = "lno";
1036 }
1037
1038 impl FromStr for Offer {
1039         type Err = Bolt12ParseError;
1040
1041         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
1042                 Self::from_bech32_str(s)
1043         }
1044 }
1045
1046 impl TryFrom<Vec<u8>> for Offer {
1047         type Error = Bolt12ParseError;
1048
1049         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
1050                 let offer = ParsedMessage::<OfferTlvStream>::try_from(bytes)?;
1051                 let ParsedMessage { bytes, tlv_stream } = offer;
1052                 let contents = OfferContents::try_from(tlv_stream)?;
1053                 let id = OfferId::from_valid_offer_tlv_stream(&bytes);
1054
1055                 Ok(Offer { bytes, contents, id })
1056         }
1057 }
1058
1059 impl TryFrom<OfferTlvStream> for OfferContents {
1060         type Error = Bolt12SemanticError;
1061
1062         fn try_from(tlv_stream: OfferTlvStream) -> Result<Self, Self::Error> {
1063                 let OfferTlvStream {
1064                         chains, metadata, currency, amount, description, features, absolute_expiry, paths,
1065                         issuer, quantity_max, node_id,
1066                 } = tlv_stream;
1067
1068                 let metadata = metadata.map(|metadata| Metadata::Bytes(metadata));
1069
1070                 let amount = match (currency, amount) {
1071                         (None, None) => None,
1072                         (None, Some(amount_msats)) if amount_msats > MAX_VALUE_MSAT => {
1073                                 return Err(Bolt12SemanticError::InvalidAmount);
1074                         },
1075                         (None, Some(amount_msats)) => Some(Amount::Bitcoin { amount_msats }),
1076                         (Some(_), None) => return Err(Bolt12SemanticError::MissingAmount),
1077                         (Some(iso4217_code), Some(amount)) => Some(Amount::Currency { iso4217_code, amount }),
1078                 };
1079
1080                 let description = match description {
1081                         None => return Err(Bolt12SemanticError::MissingDescription),
1082                         Some(description) => description,
1083                 };
1084
1085                 let features = features.unwrap_or_else(OfferFeatures::empty);
1086
1087                 let absolute_expiry = absolute_expiry
1088                         .map(|seconds_from_epoch| Duration::from_secs(seconds_from_epoch));
1089
1090                 let supported_quantity = match quantity_max {
1091                         None => Quantity::One,
1092                         Some(0) => Quantity::Unbounded,
1093                         Some(n) => Quantity::Bounded(NonZeroU64::new(n).unwrap()),
1094                 };
1095
1096                 let signing_pubkey = match node_id {
1097                         None => return Err(Bolt12SemanticError::MissingSigningPubkey),
1098                         Some(node_id) => Some(node_id),
1099                 };
1100
1101                 Ok(OfferContents {
1102                         chains, metadata, amount, description, features, absolute_expiry, issuer, paths,
1103                         supported_quantity, signing_pubkey,
1104                 })
1105         }
1106 }
1107
1108 impl core::fmt::Display for Offer {
1109         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
1110                 self.fmt_bech32_str(f)
1111         }
1112 }
1113
1114 #[cfg(test)]
1115 mod tests {
1116         use super::{Amount, Offer, OfferTlvStreamRef, Quantity};
1117         #[cfg(not(c_bindings))]
1118         use {
1119                 super::OfferBuilder,
1120         };
1121         #[cfg(c_bindings)]
1122         use {
1123                 super::OfferWithExplicitMetadataBuilder as OfferBuilder,
1124         };
1125
1126         use bitcoin::blockdata::constants::ChainHash;
1127         use bitcoin::network::constants::Network;
1128         use bitcoin::secp256k1::Secp256k1;
1129         use core::num::NonZeroU64;
1130         use core::time::Duration;
1131         use crate::blinded_path::{BlindedHop, BlindedPath, IntroductionNode};
1132         use crate::sign::KeyMaterial;
1133         use crate::ln::features::OfferFeatures;
1134         use crate::ln::inbound_payment::ExpandedKey;
1135         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
1136         use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
1137         use crate::offers::test_utils::*;
1138         use crate::util::ser::{BigSize, Writeable};
1139         use crate::util::string::PrintableString;
1140
1141         #[test]
1142         fn builds_offer_with_defaults() {
1143                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1144
1145                 let mut buffer = Vec::new();
1146                 offer.write(&mut buffer).unwrap();
1147
1148                 assert_eq!(offer.bytes, buffer.as_slice());
1149                 assert_eq!(offer.chains(), vec![ChainHash::using_genesis_block(Network::Bitcoin)]);
1150                 assert!(offer.supports_chain(ChainHash::using_genesis_block(Network::Bitcoin)));
1151                 assert_eq!(offer.metadata(), None);
1152                 assert_eq!(offer.amount(), None);
1153                 assert_eq!(offer.description(), PrintableString("foo"));
1154                 assert_eq!(offer.offer_features(), &OfferFeatures::empty());
1155                 assert_eq!(offer.absolute_expiry(), None);
1156                 #[cfg(feature = "std")]
1157                 assert!(!offer.is_expired());
1158                 assert_eq!(offer.paths(), &[]);
1159                 assert_eq!(offer.issuer(), None);
1160                 assert_eq!(offer.supported_quantity(), Quantity::One);
1161                 assert_eq!(offer.signing_pubkey(), Some(pubkey(42)));
1162
1163                 assert_eq!(
1164                         offer.as_tlv_stream(),
1165                         OfferTlvStreamRef {
1166                                 chains: None,
1167                                 metadata: None,
1168                                 currency: None,
1169                                 amount: None,
1170                                 description: Some(&String::from("foo")),
1171                                 features: None,
1172                                 absolute_expiry: None,
1173                                 paths: None,
1174                                 issuer: None,
1175                                 quantity_max: None,
1176                                 node_id: Some(&pubkey(42)),
1177                         },
1178                 );
1179
1180                 if let Err(e) = Offer::try_from(buffer) {
1181                         panic!("error parsing offer: {:?}", e);
1182                 }
1183         }
1184
1185         #[test]
1186         fn builds_offer_with_chains() {
1187                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
1188                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
1189
1190                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1191                         .chain(Network::Bitcoin)
1192                         .build()
1193                         .unwrap();
1194                 assert!(offer.supports_chain(mainnet));
1195                 assert_eq!(offer.chains(), vec![mainnet]);
1196                 assert_eq!(offer.as_tlv_stream().chains, None);
1197
1198                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1199                         .chain(Network::Testnet)
1200                         .build()
1201                         .unwrap();
1202                 assert!(offer.supports_chain(testnet));
1203                 assert_eq!(offer.chains(), vec![testnet]);
1204                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
1205
1206                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1207                         .chain(Network::Testnet)
1208                         .chain(Network::Testnet)
1209                         .build()
1210                         .unwrap();
1211                 assert!(offer.supports_chain(testnet));
1212                 assert_eq!(offer.chains(), vec![testnet]);
1213                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![testnet]));
1214
1215                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1216                         .chain(Network::Bitcoin)
1217                         .chain(Network::Testnet)
1218                         .build()
1219                         .unwrap();
1220                 assert!(offer.supports_chain(mainnet));
1221                 assert!(offer.supports_chain(testnet));
1222                 assert_eq!(offer.chains(), vec![mainnet, testnet]);
1223                 assert_eq!(offer.as_tlv_stream().chains, Some(&vec![mainnet, testnet]));
1224         }
1225
1226         #[test]
1227         fn builds_offer_with_metadata() {
1228                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1229                         .metadata(vec![42; 32]).unwrap()
1230                         .build()
1231                         .unwrap();
1232                 assert_eq!(offer.metadata(), Some(&vec![42; 32]));
1233                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![42; 32]));
1234
1235                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1236                         .metadata(vec![42; 32]).unwrap()
1237                         .metadata(vec![43; 32]).unwrap()
1238                         .build()
1239                         .unwrap();
1240                 assert_eq!(offer.metadata(), Some(&vec![43; 32]));
1241                 assert_eq!(offer.as_tlv_stream().metadata, Some(&vec![43; 32]));
1242         }
1243
1244         #[test]
1245         fn builds_offer_with_metadata_derived() {
1246                 let desc = "foo".to_string();
1247                 let node_id = recipient_pubkey();
1248                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1249                 let entropy = FixedEntropy {};
1250                 let secp_ctx = Secp256k1::new();
1251
1252                 #[cfg(c_bindings)]
1253                 use super::OfferWithDerivedMetadataBuilder as OfferBuilder;
1254                 let offer = OfferBuilder
1255                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
1256                         .amount_msats(1000)
1257                         .build().unwrap();
1258                 assert_eq!(offer.signing_pubkey(), Some(node_id));
1259
1260                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1261                         .build().unwrap()
1262                         .sign(payer_sign).unwrap();
1263                 match invoice_request.verify(&expanded_key, &secp_ctx) {
1264                         Ok(invoice_request) => assert_eq!(invoice_request.offer_id, offer.id()),
1265                         Err(_) => panic!("unexpected error"),
1266                 }
1267
1268                 // Fails verification with altered offer field
1269                 let mut tlv_stream = offer.as_tlv_stream();
1270                 tlv_stream.amount = Some(100);
1271
1272                 let mut encoded_offer = Vec::new();
1273                 tlv_stream.write(&mut encoded_offer).unwrap();
1274
1275                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1276                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1277                         .build().unwrap()
1278                         .sign(payer_sign).unwrap();
1279                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1280
1281                 // Fails verification with altered metadata
1282                 let mut tlv_stream = offer.as_tlv_stream();
1283                 let metadata = tlv_stream.metadata.unwrap().iter().copied().rev().collect();
1284                 tlv_stream.metadata = Some(&metadata);
1285
1286                 let mut encoded_offer = Vec::new();
1287                 tlv_stream.write(&mut encoded_offer).unwrap();
1288
1289                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1290                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1291                         .build().unwrap()
1292                         .sign(payer_sign).unwrap();
1293                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1294         }
1295
1296         #[test]
1297         fn builds_offer_with_derived_signing_pubkey() {
1298                 let desc = "foo".to_string();
1299                 let node_id = recipient_pubkey();
1300                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1301                 let entropy = FixedEntropy {};
1302                 let secp_ctx = Secp256k1::new();
1303
1304                 let blinded_path = BlindedPath {
1305                         introduction_node: IntroductionNode::NodeId(pubkey(40)),
1306                         blinding_point: pubkey(41),
1307                         blinded_hops: vec![
1308                                 BlindedHop { blinded_node_id: pubkey(42), encrypted_payload: vec![0; 43] },
1309                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
1310                         ],
1311                 };
1312
1313                 #[cfg(c_bindings)]
1314                 use super::OfferWithDerivedMetadataBuilder as OfferBuilder;
1315                 let offer = OfferBuilder
1316                         ::deriving_signing_pubkey(desc, node_id, &expanded_key, &entropy, &secp_ctx)
1317                         .amount_msats(1000)
1318                         .path(blinded_path)
1319                         .build().unwrap();
1320                 assert_ne!(offer.signing_pubkey(), Some(node_id));
1321
1322                 let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1323                         .build().unwrap()
1324                         .sign(payer_sign).unwrap();
1325                 match invoice_request.verify(&expanded_key, &secp_ctx) {
1326                         Ok(invoice_request) => assert_eq!(invoice_request.offer_id, offer.id()),
1327                         Err(_) => panic!("unexpected error"),
1328                 }
1329
1330                 // Fails verification with altered offer field
1331                 let mut tlv_stream = offer.as_tlv_stream();
1332                 tlv_stream.amount = Some(100);
1333
1334                 let mut encoded_offer = Vec::new();
1335                 tlv_stream.write(&mut encoded_offer).unwrap();
1336
1337                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1338                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1339                         .build().unwrap()
1340                         .sign(payer_sign).unwrap();
1341                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1342
1343                 // Fails verification with altered signing pubkey
1344                 let mut tlv_stream = offer.as_tlv_stream();
1345                 let signing_pubkey = pubkey(1);
1346                 tlv_stream.node_id = Some(&signing_pubkey);
1347
1348                 let mut encoded_offer = Vec::new();
1349                 tlv_stream.write(&mut encoded_offer).unwrap();
1350
1351                 let invoice_request = Offer::try_from(encoded_offer).unwrap()
1352                         .request_invoice(vec![1; 32], payer_pubkey()).unwrap()
1353                         .build().unwrap()
1354                         .sign(payer_sign).unwrap();
1355                 assert!(invoice_request.verify(&expanded_key, &secp_ctx).is_err());
1356         }
1357
1358         #[test]
1359         fn builds_offer_with_amount() {
1360                 let bitcoin_amount = Amount::Bitcoin { amount_msats: 1000 };
1361                 let currency_amount = Amount::Currency { iso4217_code: *b"USD", amount: 10 };
1362
1363                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1364                         .amount_msats(1000)
1365                         .build()
1366                         .unwrap();
1367                 let tlv_stream = offer.as_tlv_stream();
1368                 assert_eq!(offer.amount(), Some(&bitcoin_amount));
1369                 assert_eq!(tlv_stream.amount, Some(1000));
1370                 assert_eq!(tlv_stream.currency, None);
1371
1372                 #[cfg(not(c_bindings))]
1373                 let builder = OfferBuilder::new("foo".into(), pubkey(42))
1374                         .amount(currency_amount.clone());
1375                 #[cfg(c_bindings)]
1376                 let mut builder = OfferBuilder::new("foo".into(), pubkey(42));
1377                 #[cfg(c_bindings)]
1378                 builder.amount(currency_amount.clone());
1379                 let tlv_stream = builder.offer.as_tlv_stream();
1380                 assert_eq!(builder.offer.amount, Some(currency_amount.clone()));
1381                 assert_eq!(tlv_stream.amount, Some(10));
1382                 assert_eq!(tlv_stream.currency, Some(b"USD"));
1383                 match builder.build() {
1384                         Ok(_) => panic!("expected error"),
1385                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnsupportedCurrency),
1386                 }
1387
1388                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1389                         .amount(currency_amount.clone())
1390                         .amount(bitcoin_amount.clone())
1391                         .build()
1392                         .unwrap();
1393                 let tlv_stream = offer.as_tlv_stream();
1394                 assert_eq!(tlv_stream.amount, Some(1000));
1395                 assert_eq!(tlv_stream.currency, None);
1396
1397                 let invalid_amount = Amount::Bitcoin { amount_msats: MAX_VALUE_MSAT + 1 };
1398                 match OfferBuilder::new("foo".into(), pubkey(42)).amount(invalid_amount).build() {
1399                         Ok(_) => panic!("expected error"),
1400                         Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
1401                 }
1402         }
1403
1404         #[test]
1405         fn builds_offer_with_features() {
1406                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1407                         .features_unchecked(OfferFeatures::unknown())
1408                         .build()
1409                         .unwrap();
1410                 assert_eq!(offer.offer_features(), &OfferFeatures::unknown());
1411                 assert_eq!(offer.as_tlv_stream().features, Some(&OfferFeatures::unknown()));
1412
1413                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1414                         .features_unchecked(OfferFeatures::unknown())
1415                         .features_unchecked(OfferFeatures::empty())
1416                         .build()
1417                         .unwrap();
1418                 assert_eq!(offer.offer_features(), &OfferFeatures::empty());
1419                 assert_eq!(offer.as_tlv_stream().features, None);
1420         }
1421
1422         #[test]
1423         fn builds_offer_with_absolute_expiry() {
1424                 let future_expiry = Duration::from_secs(u64::max_value());
1425                 let past_expiry = Duration::from_secs(0);
1426                 let now = future_expiry - Duration::from_secs(1_000);
1427
1428                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1429                         .absolute_expiry(future_expiry)
1430                         .build()
1431                         .unwrap();
1432                 #[cfg(feature = "std")]
1433                 assert!(!offer.is_expired());
1434                 assert!(!offer.is_expired_no_std(now));
1435                 assert_eq!(offer.absolute_expiry(), Some(future_expiry));
1436                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(future_expiry.as_secs()));
1437
1438                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1439                         .absolute_expiry(future_expiry)
1440                         .absolute_expiry(past_expiry)
1441                         .build()
1442                         .unwrap();
1443                 #[cfg(feature = "std")]
1444                 assert!(offer.is_expired());
1445                 assert!(offer.is_expired_no_std(now));
1446                 assert_eq!(offer.absolute_expiry(), Some(past_expiry));
1447                 assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(past_expiry.as_secs()));
1448         }
1449
1450         #[test]
1451         fn builds_offer_with_paths() {
1452                 let paths = vec![
1453                         BlindedPath {
1454                                 introduction_node: IntroductionNode::NodeId(pubkey(40)),
1455                                 blinding_point: pubkey(41),
1456                                 blinded_hops: vec![
1457                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1458                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1459                                 ],
1460                         },
1461                         BlindedPath {
1462                                 introduction_node: IntroductionNode::NodeId(pubkey(40)),
1463                                 blinding_point: pubkey(41),
1464                                 blinded_hops: vec![
1465                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1466                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1467                                 ],
1468                         },
1469                 ];
1470
1471                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1472                         .path(paths[0].clone())
1473                         .path(paths[1].clone())
1474                         .build()
1475                         .unwrap();
1476                 let tlv_stream = offer.as_tlv_stream();
1477                 assert_eq!(offer.paths(), paths.as_slice());
1478                 assert_eq!(offer.signing_pubkey(), Some(pubkey(42)));
1479                 assert_ne!(pubkey(42), pubkey(44));
1480                 assert_eq!(tlv_stream.paths, Some(&paths));
1481                 assert_eq!(tlv_stream.node_id, Some(&pubkey(42)));
1482         }
1483
1484         #[test]
1485         fn builds_offer_with_issuer() {
1486                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1487                         .issuer("bar".into())
1488                         .build()
1489                         .unwrap();
1490                 assert_eq!(offer.issuer(), Some(PrintableString("bar")));
1491                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("bar")));
1492
1493                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1494                         .issuer("bar".into())
1495                         .issuer("baz".into())
1496                         .build()
1497                         .unwrap();
1498                 assert_eq!(offer.issuer(), Some(PrintableString("baz")));
1499                 assert_eq!(offer.as_tlv_stream().issuer, Some(&String::from("baz")));
1500         }
1501
1502         #[test]
1503         fn builds_offer_with_supported_quantity() {
1504                 let one = NonZeroU64::new(1).unwrap();
1505                 let ten = NonZeroU64::new(10).unwrap();
1506
1507                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1508                         .supported_quantity(Quantity::One)
1509                         .build()
1510                         .unwrap();
1511                 let tlv_stream = offer.as_tlv_stream();
1512                 assert_eq!(offer.supported_quantity(), Quantity::One);
1513                 assert_eq!(tlv_stream.quantity_max, None);
1514
1515                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1516                         .supported_quantity(Quantity::Unbounded)
1517                         .build()
1518                         .unwrap();
1519                 let tlv_stream = offer.as_tlv_stream();
1520                 assert_eq!(offer.supported_quantity(), Quantity::Unbounded);
1521                 assert_eq!(tlv_stream.quantity_max, Some(0));
1522
1523                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1524                         .supported_quantity(Quantity::Bounded(ten))
1525                         .build()
1526                         .unwrap();
1527                 let tlv_stream = offer.as_tlv_stream();
1528                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(ten));
1529                 assert_eq!(tlv_stream.quantity_max, Some(10));
1530
1531                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1532                         .supported_quantity(Quantity::Bounded(one))
1533                         .build()
1534                         .unwrap();
1535                 let tlv_stream = offer.as_tlv_stream();
1536                 assert_eq!(offer.supported_quantity(), Quantity::Bounded(one));
1537                 assert_eq!(tlv_stream.quantity_max, Some(1));
1538
1539                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1540                         .supported_quantity(Quantity::Bounded(ten))
1541                         .supported_quantity(Quantity::One)
1542                         .build()
1543                         .unwrap();
1544                 let tlv_stream = offer.as_tlv_stream();
1545                 assert_eq!(offer.supported_quantity(), Quantity::One);
1546                 assert_eq!(tlv_stream.quantity_max, None);
1547         }
1548
1549         #[test]
1550         fn fails_requesting_invoice_with_unknown_required_features() {
1551                 match OfferBuilder::new("foo".into(), pubkey(42))
1552                         .features_unchecked(OfferFeatures::unknown())
1553                         .build().unwrap()
1554                         .request_invoice(vec![1; 32], pubkey(43))
1555                 {
1556                         Ok(_) => panic!("expected error"),
1557                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnknownRequiredFeatures),
1558                 }
1559         }
1560
1561         #[test]
1562         fn parses_offer_with_chains() {
1563                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1564                         .chain(Network::Bitcoin)
1565                         .chain(Network::Testnet)
1566                         .build()
1567                         .unwrap();
1568                 if let Err(e) = offer.to_string().parse::<Offer>() {
1569                         panic!("error parsing offer: {:?}", e);
1570                 }
1571         }
1572
1573         #[test]
1574         fn parses_offer_with_amount() {
1575                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1576                         .amount(Amount::Bitcoin { amount_msats: 1000 })
1577                         .build()
1578                         .unwrap();
1579                 if let Err(e) = offer.to_string().parse::<Offer>() {
1580                         panic!("error parsing offer: {:?}", e);
1581                 }
1582
1583                 let mut tlv_stream = offer.as_tlv_stream();
1584                 tlv_stream.amount = Some(1000);
1585                 tlv_stream.currency = Some(b"USD");
1586
1587                 let mut encoded_offer = Vec::new();
1588                 tlv_stream.write(&mut encoded_offer).unwrap();
1589
1590                 if let Err(e) = Offer::try_from(encoded_offer) {
1591                         panic!("error parsing offer: {:?}", e);
1592                 }
1593
1594                 let mut tlv_stream = offer.as_tlv_stream();
1595                 tlv_stream.amount = None;
1596                 tlv_stream.currency = Some(b"USD");
1597
1598                 let mut encoded_offer = Vec::new();
1599                 tlv_stream.write(&mut encoded_offer).unwrap();
1600
1601                 match Offer::try_from(encoded_offer) {
1602                         Ok(_) => panic!("expected error"),
1603                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingAmount)),
1604                 }
1605
1606                 let mut tlv_stream = offer.as_tlv_stream();
1607                 tlv_stream.amount = Some(MAX_VALUE_MSAT + 1);
1608                 tlv_stream.currency = None;
1609
1610                 let mut encoded_offer = Vec::new();
1611                 tlv_stream.write(&mut encoded_offer).unwrap();
1612
1613                 match Offer::try_from(encoded_offer) {
1614                         Ok(_) => panic!("expected error"),
1615                         Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InvalidAmount)),
1616                 }
1617         }
1618
1619         #[test]
1620         fn parses_offer_with_description() {
1621                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1622                 if let Err(e) = offer.to_string().parse::<Offer>() {
1623                         panic!("error parsing offer: {:?}", e);
1624                 }
1625
1626                 let mut tlv_stream = offer.as_tlv_stream();
1627                 tlv_stream.description = None;
1628
1629                 let mut encoded_offer = Vec::new();
1630                 tlv_stream.write(&mut encoded_offer).unwrap();
1631
1632                 match Offer::try_from(encoded_offer) {
1633                         Ok(_) => panic!("expected error"),
1634                         Err(e) => {
1635                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription));
1636                         },
1637                 }
1638         }
1639
1640         #[test]
1641         fn parses_offer_with_paths() {
1642                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1643                         .path(BlindedPath {
1644                                 introduction_node: IntroductionNode::NodeId(pubkey(40)),
1645                                 blinding_point: pubkey(41),
1646                                 blinded_hops: vec![
1647                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1648                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1649                                 ],
1650                         })
1651                         .path(BlindedPath {
1652                                 introduction_node: IntroductionNode::NodeId(pubkey(40)),
1653                                 blinding_point: pubkey(41),
1654                                 blinded_hops: vec![
1655                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1656                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1657                                 ],
1658                         })
1659                         .build()
1660                         .unwrap();
1661                 if let Err(e) = offer.to_string().parse::<Offer>() {
1662                         panic!("error parsing offer: {:?}", e);
1663                 }
1664
1665                 let mut builder = OfferBuilder::new("foo".into(), pubkey(42));
1666                 builder.offer.paths = Some(vec![]);
1667
1668                 let offer = builder.build().unwrap();
1669                 if let Err(e) = offer.to_string().parse::<Offer>() {
1670                         panic!("error parsing offer: {:?}", e);
1671                 }
1672         }
1673
1674         #[test]
1675         fn parses_offer_with_quantity() {
1676                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1677                         .supported_quantity(Quantity::One)
1678                         .build()
1679                         .unwrap();
1680                 if let Err(e) = offer.to_string().parse::<Offer>() {
1681                         panic!("error parsing offer: {:?}", e);
1682                 }
1683
1684                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1685                         .supported_quantity(Quantity::Unbounded)
1686                         .build()
1687                         .unwrap();
1688                 if let Err(e) = offer.to_string().parse::<Offer>() {
1689                         panic!("error parsing offer: {:?}", e);
1690                 }
1691
1692                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1693                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(10).unwrap()))
1694                         .build()
1695                         .unwrap();
1696                 if let Err(e) = offer.to_string().parse::<Offer>() {
1697                         panic!("error parsing offer: {:?}", e);
1698                 }
1699
1700                 let offer = OfferBuilder::new("foo".into(), pubkey(42))
1701                         .supported_quantity(Quantity::Bounded(NonZeroU64::new(1).unwrap()))
1702                         .build()
1703                         .unwrap();
1704                 if let Err(e) = offer.to_string().parse::<Offer>() {
1705                         panic!("error parsing offer: {:?}", e);
1706                 }
1707         }
1708
1709         #[test]
1710         fn parses_offer_with_node_id() {
1711                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1712                 if let Err(e) = offer.to_string().parse::<Offer>() {
1713                         panic!("error parsing offer: {:?}", e);
1714                 }
1715
1716                 let mut tlv_stream = offer.as_tlv_stream();
1717                 tlv_stream.node_id = None;
1718
1719                 let mut encoded_offer = Vec::new();
1720                 tlv_stream.write(&mut encoded_offer).unwrap();
1721
1722                 match Offer::try_from(encoded_offer) {
1723                         Ok(_) => panic!("expected error"),
1724                         Err(e) => {
1725                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingSigningPubkey));
1726                         },
1727                 }
1728         }
1729
1730         #[test]
1731         fn fails_parsing_offer_with_extra_tlv_records() {
1732                 let offer = OfferBuilder::new("foo".into(), pubkey(42)).build().unwrap();
1733
1734                 let mut encoded_offer = Vec::new();
1735                 offer.write(&mut encoded_offer).unwrap();
1736                 BigSize(80).write(&mut encoded_offer).unwrap();
1737                 BigSize(32).write(&mut encoded_offer).unwrap();
1738                 [42u8; 32].write(&mut encoded_offer).unwrap();
1739
1740                 match Offer::try_from(encoded_offer) {
1741                         Ok(_) => panic!("expected error"),
1742                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1743                 }
1744         }
1745 }
1746
1747 #[cfg(test)]
1748 mod bolt12_tests {
1749         use super::{Bolt12ParseError, Bolt12SemanticError, Offer};
1750         use crate::ln::msgs::DecodeError;
1751
1752         #[test]
1753         fn parses_bech32_encoded_offers() {
1754                 let offers = [
1755                         // Minimal bolt12 offer
1756                         "lno1pgx9getnwss8vetrw3hhyuckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1757
1758                         // for testnet
1759                         "lno1qgsyxjtl6luzd9t3pr62xr7eemp6awnejusgf6gw45q75vcfqqqqqqq2p32x2um5ypmx2cm5dae8x93pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpj",
1760
1761                         // for bitcoin (redundant)
1762                         "lno1qgsxlc5vp2m0rvmjcxn2y34wv0m5lyc7sdj7zksgn35dvxgqqqqqqqq2p32x2um5ypmx2cm5dae8x93pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpj",
1763
1764                         // for bitcoin or liquidv1
1765                         "lno1qfqpge38tqmzyrdjj3x2qkdr5y80dlfw56ztq6yd9sme995g3gsxqqm0u2xq4dh3kdevrf4zg6hx8a60jv0gxe0ptgyfc6xkryqqqqqqqq9qc4r9wd6zqan9vd6x7unnzcss9mk8y3wkklfvevcrszlmu23kfrxh49px20665dqwmn4p72pksese",
1766
1767                         // with metadata
1768                         "lno1qsgqqqqqqqqqqqqqqqqqqqqqqqqqqzsv23jhxapqwejkxar0wfe3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1769
1770                         // with amount
1771                         "lno1pqpzwyq2p32x2um5ypmx2cm5dae8x93pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpj",
1772
1773                         // with currency
1774                         "lno1qcp4256ypqpzwyq2p32x2um5ypmx2cm5dae8x93pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpj",
1775
1776                         // with expiry
1777                         "lno1pgx9getnwss8vetrw3hhyucwq3ay997czcss9mk8y3wkklfvevcrszlmu23kfrxh49px20665dqwmn4p72pksese",
1778
1779                         // with issuer
1780                         "lno1pgx9getnwss8vetrw3hhyucjy358garswvaz7tmzdak8gvfj9ehhyeeqgf85c4p3xgsxjmnyw4ehgunfv4e3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1781
1782                         // with quantity
1783                         "lno1pgx9getnwss8vetrw3hhyuc5qyz3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1784
1785                         // with unlimited (or unknown) quantity
1786                         "lno1pgx9getnwss8vetrw3hhyuc5qqtzzqhwcuj966ma9n9nqwqtl032xeyv6755yeflt235pmww58egx6rxry",
1787
1788                         // with single quantity (weird but valid)
1789                         "lno1pgx9getnwss8vetrw3hhyuc5qyq3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1790
1791                         // with feature
1792                         "lno1pgx9getnwss8vetrw3hhyucvp5yqqqqqqqqqqqqqqqqqqqqkyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg",
1793
1794                         // with blinded path via Bob (0x424242...), blinding 020202...
1795                         "lno1pgx9getnwss8vetrw3hhyucs5ypjgef743p5fzqq9nqxh0ah7y87rzv3ud0eleps9kl2d5348hq2k8qzqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgqpqqqqqqqqqqqqqqqqqqqqqqqqqqqzqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqqzq3zyg3zyg3zyg3vggzamrjghtt05kvkvpcp0a79gmy3nt6jsn98ad2xs8de6sl9qmgvcvs",
1796
1797                         // ... and with second blinded path via Carol (0x434343...), blinding 020202...
1798                         "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",
1799
1800                         // unknown odd field
1801                         "lno1pgx9getnwss8vetrw3hhyuckyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxfppf5x2mrvdamk7unvvs",
1802                 ];
1803                 for encoded_offer in &offers {
1804                         if let Err(e) = encoded_offer.parse::<Offer>() {
1805                                 panic!("Invalid offer ({:?}): {}", e, encoded_offer);
1806                         }
1807                 }
1808         }
1809
1810         #[test]
1811         fn fails_parsing_bech32_encoded_offers() {
1812                 // Malformed: fields out of order
1813                 assert_eq!(
1814                         "lno1zcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszpgz5znzfgdzs".parse::<Offer>(),
1815                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1816                 );
1817
1818                 // Malformed: unknown even TLV type 78
1819                 assert_eq!(
1820                         "lno1pgz5znzfgdz3vggzqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpysgr0u2xq4dh3kdevrf4zg6hx8a60jv0gxe0ptgyfc6xkryqqqqqqqq".parse::<Offer>(),
1821                         Err(Bolt12ParseError::Decode(DecodeError::UnknownRequiredFeature)),
1822                 );
1823
1824                 // Malformed: empty
1825                 assert_eq!(
1826                         "lno1".parse::<Offer>(),
1827                         Err(Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription)),
1828                 );
1829
1830                 // Malformed: truncated at type
1831                 assert_eq!(
1832                         "lno1pg".parse::<Offer>(),
1833                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1834                 );
1835
1836                 // Malformed: truncated in length
1837                 assert_eq!(
1838                         "lno1pt7s".parse::<Offer>(),
1839                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1840                 );
1841
1842                 // Malformed: truncated after length
1843                 assert_eq!(
1844                         "lno1pgpq".parse::<Offer>(),
1845                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1846                 );
1847
1848                 // Malformed: truncated in description
1849                 assert_eq!(
1850                         "lno1pgpyz".parse::<Offer>(),
1851                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1852                 );
1853
1854                 // Malformed: invalid offer_chains length
1855                 assert_eq!(
1856                         "lno1qgqszzs9g9xyjs69zcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1857                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1858                 );
1859
1860                 // Malformed: truncated currency UTF-8
1861                 assert_eq!(
1862                         "lno1qcqcqzs9g9xyjs69zcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1863                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1864                 );
1865
1866                 // Malformed: invalid currency UTF-8
1867                 assert_eq!(
1868                         "lno1qcpgqsg2q4q5cj2rg5tzzqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqg".parse::<Offer>(),
1869                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1870                 );
1871
1872                 // Malformed: truncated description UTF-8
1873                 assert_eq!(
1874                         "lno1pgqcq93pqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqy".parse::<Offer>(),
1875                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1876                 );
1877
1878                 // Malformed: invalid description UTF-8
1879                 assert_eq!(
1880                         "lno1pgpgqsgkyypqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqs".parse::<Offer>(),
1881                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1882                 );
1883
1884                 // Malformed: truncated offer_paths
1885                 assert_eq!(
1886                         "lno1pgz5znzfgdz3qqgpzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1887                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1888                 );
1889
1890                 // Malformed: zero num_hops in blinded_path
1891                 assert_eq!(
1892                         "lno1pgz5znzfgdz3qqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1893                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1894                 );
1895
1896                 // Malformed: truncated onionmsg_hop in blinded_path
1897                 assert_eq!(
1898                         "lno1pgz5znzfgdz3qqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqspqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqgkyypqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqs".parse::<Offer>(),
1899                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1900                 );
1901
1902                 // Malformed: bad first_node_id in blinded_path
1903                 assert_eq!(
1904                         "lno1pgz5znzfgdz3qqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqspqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqgqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1905                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1906                 );
1907
1908                 // Malformed: bad blinding in blinded_path
1909                 assert_eq!(
1910                         "lno1pgz5znzfgdz3qqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcpqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqgqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1911                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1912                 );
1913
1914                 // Malformed: bad blinded_node_id in onionmsg_hop
1915                 assert_eq!(
1916                         "lno1pgz5znzfgdz3qqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqspqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqgqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1917                         Err(Bolt12ParseError::Decode(DecodeError::ShortRead)),
1918                 );
1919
1920                 // Malformed: truncated issuer UTF-8
1921                 assert_eq!(
1922                         "lno1pgz5znzfgdz3yqvqzcssyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqsz".parse::<Offer>(),
1923                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1924                 );
1925
1926                 // Malformed: invalid issuer UTF-8
1927                 assert_eq!(
1928                         "lno1pgz5znzfgdz3yq5qgytzzqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqg".parse::<Offer>(),
1929                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1930                 );
1931
1932                 // Malformed: invalid offer_node_id
1933                 assert_eq!(
1934                         "lno1pgz5znzfgdz3vggzqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvpsxqcrqvps".parse::<Offer>(),
1935                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1936                 );
1937
1938                 // Contains type >= 80
1939                 assert_eq!(
1940                         "lno1pgz5znzfgdz3vggzqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgp9qgr0u2xq4dh3kdevrf4zg6hx8a60jv0gxe0ptgyfc6xkryqqqqqqqq".parse::<Offer>(),
1941                         Err(Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1942                 );
1943
1944                 // TODO: Resolved in spec https://github.com/lightning/bolts/pull/798/files#r1334851959
1945                 // Contains unknown feature 22
1946                 assert!(
1947                         "lno1pgx9getnwss8vetrw3hhyucvqdqqqqqkyypwa3eyt44h6txtxquqh7lz5djge4afgfjn7k4rgrkuag0jsd5xvxg".parse::<Offer>().is_ok()
1948                 );
1949
1950                 // Missing offer_description
1951                 assert_eq!(
1952                         "lno1zcss9mk8y3wkklfvevcrszlmu23kfrxh49px20665dqwmn4p72pksese".parse::<Offer>(),
1953                         Err(Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription)),
1954                 );
1955
1956                 // Missing offer_node_id"
1957                 assert_eq!(
1958                         "lno1pgx9getnwss8vetrw3hhyuc".parse::<Offer>(),
1959                         Err(Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingSigningPubkey)),
1960                 );
1961         }
1962 }