_ Git - rust-lightning/blob - lightning/src/offers/refund.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 refunds.
  11 //!
  12 //! A [`Refund`] is an "offer for money" and is typically constructed by a merchant and presented
  13 //! directly to the customer. The recipient responds with a [`Bolt12Invoice`] to be paid.
  14 //!
  15 //! This is an [`InvoiceRequest`] produced *not* in response to an [`Offer`].
  16 //!
  17 //! [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
  18 //! [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
  19 //! [`Offer`]: crate::offers::offer::Offer
  20 //!
  21 //! # Example
  22 //!
  23 //! ```
  24 //! extern crate bitcoin;
  25 //! extern crate core;
  26 //! extern crate lightning;
  27 //!
  28 //! use core::convert::TryFrom;
  29 //! use core::time::Duration;
  30 //!
  31 //! use bitcoin::network::constants::Network;
  32 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
  33 //! use lightning::offers::parse::Bolt12ParseError;
  34 //! use lightning::offers::refund::{Refund, RefundBuilder};
  35 //! use lightning::util::ser::{Readable, Writeable};
  36 //!
  37 //! # use lightning::blinded_path::BlindedPath;
  38 //! # #[cfg(feature = "std")]
  39 //! # use std::time::SystemTime;
  40 //! #
  41 //! # fn create_blinded_path() -> BlindedPath { unimplemented!() }
  42 //! # fn create_another_blinded_path() -> BlindedPath { unimplemented!() }
  43 //! #
  44 //! # #[cfg(feature = "std")]
  45 //! # fn build() -> Result<(), Bolt12ParseError> {
  46 //! let secp_ctx = Secp256k1::new();
  47 //! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
  48 //! let pubkey = PublicKey::from(keys);
  49 //!
  50 //! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
  51 //! let refund = RefundBuilder::new("coffee, large".to_string(), vec![1; 32], pubkey, 20_000)?
  52 //!     .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
  53 //!     .issuer("Foo Bar".to_string())
  54 //!     .path(create_blinded_path())
  55 //!     .path(create_another_blinded_path())
  56 //!     .chain(Network::Bitcoin)
  57 //!     .payer_note("refund for order #12345".to_string())
  58 //!     .build()?;
  59 //!
  60 //! // Encode as a bech32 string for use in a QR code.
  61 //! let encoded_refund = refund.to_string();
  62 //!
  63 //! // Parse from a bech32 string after scanning from a QR code.
  64 //! let refund = encoded_refund.parse::<Refund>()?;
  65 //!
  66 //! // Encode refund as raw bytes.
  67 //! let mut bytes = Vec::new();
  68 //! refund.write(&mut bytes).unwrap();
  69 //!
  70 //! // Decode raw bytes into an refund.
  71 //! let refund = Refund::try_from(bytes)?;
  72 //! # Ok(())
  73 //! # }
  74 //! ```
  75 //!
  76 //! # Note
  77 //!
  78 //! If constructing a [`Refund`] for use with a [`ChannelManager`], use
  79 //! [`ChannelManager::create_refund_builder`] instead of [`RefundBuilder::new`].
  80 //!
  81 //! [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
  82 //! [`ChannelManager::create_refund_builder`]: crate::ln::channelmanager::ChannelManager::create_refund_builder
  83
  84 use bitcoin::blockdata::constants::ChainHash;
  85 use bitcoin::network::constants::Network;
  86 use bitcoin::secp256k1::{PublicKey, Secp256k1, self};
  87 use core::convert::TryFrom;
  88 use core::ops::Deref;
  89 use core::str::FromStr;
  90 use core::time::Duration;
  91 use crate::sign::EntropySource;
  92 use crate::io;
  93 use crate::blinded_path::BlindedPath;
  94 use crate::ln::PaymentHash;
  95 use crate::ln::channelmanager::PaymentId;
  96 use crate::ln::features::InvoiceRequestFeatures;
  97 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
  98 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
  99 use crate::offers::invoice::{BlindedPayInfo, DerivedSigningPubkey, ExplicitSigningPubkey, InvoiceBuilder};
 100 use crate::offers::invoice_request::{InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef};
 101 use crate::offers::offer::{OfferTlvStream, OfferTlvStreamRef};
 102 use crate::offers::parse::{Bech32Encode, Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
 103 use crate::offers::payer::{PayerContents, PayerTlvStream, PayerTlvStreamRef};
 104 use crate::offers::signer::{Metadata, MetadataMaterial, self};
 105 use crate::util::ser::{SeekReadable, WithoutLength, Writeable, Writer};
 106 use crate::util::string::PrintableString;
 107
 108 use crate::prelude::*;
 109
 110 #[cfg(feature = "std")]
 111 use std::time::SystemTime;
 112
 113 pub(super) const IV_BYTES: &[u8; IV_LEN] = b"LDK Refund ~~~~~";
 114
 115 /// Builds a [`Refund`] for the "offer for money" flow.
 116 ///
 117 /// See [module-level documentation] for usage.
 118 ///
 119 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 120 ///
 121 /// [module-level documentation]: self
 122 pub struct RefundBuilder<'a, T: secp256k1::Signing> {
 123         refund: RefundContents,
 124         secp_ctx: Option<&'a Secp256k1<T>>,
 125 }
 126
 127 /// Builds a [`Refund`] for the "offer for money" flow.
 128 ///
 129 /// See [module-level documentation] for usage.
 130 ///
 131 /// [module-level documentation]: self
 132 #[cfg(c_bindings)]
 133 pub struct RefundMaybeWithDerivedMetadataBuilder<'a> {
 134         refund: RefundContents,
 135         secp_ctx: Option<&'a Secp256k1<secp256k1::All>>,
 136 }
 137
 138 macro_rules! refund_explicit_metadata_builder_methods { () => {
 139         /// Creates a new builder for a refund using the [`Refund::payer_id`] for the public node id to
 140         /// send to if no [`Refund::paths`] are set. Otherwise, it may be a transient pubkey.
 141         ///
 142         /// Additionally, sets the required [`Refund::description`], [`Refund::payer_metadata`], and
 143         /// [`Refund::amount_msats`].
 144         ///
 145         /// # Note
 146         ///
 147         /// If constructing a [`Refund`] for use with a [`ChannelManager`], use
 148         /// [`ChannelManager::create_refund_builder`] instead of [`RefundBuilder::new`].
 149         ///
 150         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 151         /// [`ChannelManager::create_refund_builder`]: crate::ln::channelmanager::ChannelManager::create_refund_builder
 152         pub fn new(
 153                 description: String, metadata: Vec<u8>, payer_id: PublicKey, amount_msats: u64
 154         ) -> Result<Self, Bolt12SemanticError> {
 155                 if amount_msats > MAX_VALUE_MSAT {
 156                         return Err(Bolt12SemanticError::InvalidAmount);
 157                 }
 158
 159                 let metadata = Metadata::Bytes(metadata);
 160                 Ok(Self {
 161                         refund: RefundContents {
 162                                 payer: PayerContents(metadata), description, absolute_expiry: None, issuer: None,
 163                                 paths: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
 164                                 quantity: None, payer_id, payer_note: None,
 165                         },
 166                         secp_ctx: None,
 167                 })
 168         }
 169 } }
 170
 171 macro_rules! refund_builder_methods { (
 172         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr, $secp_context: ty $(, $self_mut: tt)?
 173 ) => {
 174         /// Similar to [`RefundBuilder::new`] except, if [`RefundBuilder::path`] is called, the payer id
 175         /// is derived from the given [`ExpandedKey`] and nonce. This provides sender privacy by using a
 176         /// different payer id for each refund, assuming a different nonce is used.  Otherwise, the
 177         /// provided `node_id` is used for the payer id.
 178         ///
 179         /// Also, sets the metadata when [`RefundBuilder::build`] is called such that it can be used to
 180         /// verify that an [`InvoiceRequest`] was produced for the refund given an [`ExpandedKey`].
 181         ///
 182         /// The `payment_id` is encrypted in the metadata and should be unique. This ensures that only
 183         /// one invoice will be paid for the refund and that payments can be uniquely identified.
 184         ///
 185         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 186         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 187         pub fn deriving_payer_id<ES: Deref>(
 188                 description: String, node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 189                 secp_ctx: &'a Secp256k1<$secp_context>, amount_msats: u64, payment_id: PaymentId
 190         ) -> Result<Self, Bolt12SemanticError> where ES::Target: EntropySource {
 191                 if amount_msats > MAX_VALUE_MSAT {
 192                         return Err(Bolt12SemanticError::InvalidAmount);
 193                 }
 194
 195                 let nonce = Nonce::from_entropy_source(entropy_source);
 196                 let payment_id = Some(payment_id);
 197                 let derivation_material = MetadataMaterial::new(nonce, expanded_key, IV_BYTES, payment_id);
 198                 let metadata = Metadata::DerivedSigningPubkey(derivation_material);
 199                 Ok(Self {
 200                         refund: RefundContents {
 201                                 payer: PayerContents(metadata), description, absolute_expiry: None, issuer: None,
 202                                 paths: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
 203                                 quantity: None, payer_id: node_id, payer_note: None,
 204                         },
 205                         secp_ctx: Some(secp_ctx),
 206                 })
 207         }
 208
 209         /// Sets the [`Refund::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
 210         /// already passed is valid and can be checked for using [`Refund::is_expired`].
 211         ///
 212         /// Successive calls to this method will override the previous setting.
 213         pub fn absolute_expiry($($self_mut)* $self: $self_type, absolute_expiry: Duration) -> $return_type {
 214                 $self.refund.absolute_expiry = Some(absolute_expiry);
 215                 $return_value
 216         }
 217
 218         /// Sets the [`Refund::issuer`].
 219         ///
 220         /// Successive calls to this method will override the previous setting.
 221         pub fn issuer($($self_mut)* $self: $self_type, issuer: String) -> $return_type {
 222                 $self.refund.issuer = Some(issuer);
 223                 $return_value
 224         }
 225
 226         /// Adds a blinded path to [`Refund::paths`]. Must include at least one path if only connected
 227         /// by private channels or if [`Refund::payer_id`] is not a public node id.
 228         ///
 229         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 230         /// adding duplicate paths.
 231         pub fn path($($self_mut)* $self: $self_type, path: BlindedPath) -> $return_type {
 232                 $self.refund.paths.get_or_insert_with(Vec::new).push(path);
 233                 $return_value
 234         }
 235
 236         /// Sets the [`Refund::chain`] of the given [`Network`] for paying an invoice. If not
 237         /// called, [`Network::Bitcoin`] is assumed.
 238         ///
 239         /// Successive calls to this method will override the previous setting.
 240         pub fn chain($self: $self_type, network: Network) -> $return_type {
 241                 $self.chain_hash(ChainHash::using_genesis_block(network))
 242         }
 243
 244         /// Sets the [`Refund::chain`] of the given [`ChainHash`] for paying an invoice. If not called,
 245         /// [`Network::Bitcoin`] is assumed.
 246         ///
 247         /// Successive calls to this method will override the previous setting.
 248         pub(crate) fn chain_hash($($self_mut)* $self: $self_type, chain: ChainHash) -> $return_type {
 249                 $self.refund.chain = Some(chain);
 250                 $return_value
 251         }
 252
 253         /// Sets [`Refund::quantity`] of items. This is purely for informational purposes. It is useful
 254         /// when the refund pertains to a [`Bolt12Invoice`] that paid for more than one item from an
 255         /// [`Offer`] as specified by [`InvoiceRequest::quantity`].
 256         ///
 257         /// Successive calls to this method will override the previous setting.
 258         ///
 259         /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 260         /// [`InvoiceRequest::quantity`]: crate::offers::invoice_request::InvoiceRequest::quantity
 261         /// [`Offer`]: crate::offers::offer::Offer
 262         pub fn quantity($($self_mut)* $self: $self_type, quantity: u64) -> $return_type {
 263                 $self.refund.quantity = Some(quantity);
 264                 $return_value
 265         }
 266
 267         /// Sets the [`Refund::payer_note`].
 268         ///
 269         /// Successive calls to this method will override the previous setting.
 270         pub fn payer_note($($self_mut)* $self: $self_type, payer_note: String) -> $return_type {
 271                 $self.refund.payer_note = Some(payer_note);
 272                 $return_value
 273         }
 274
 275         /// Builds a [`Refund`] after checking for valid semantics.
 276         pub fn build($($self_mut)* $self: $self_type) -> Result<Refund, Bolt12SemanticError> {
 277                 if $self.refund.chain() == $self.refund.implied_chain() {
 278                         $self.refund.chain = None;
 279                 }
 280
 281                 // Create the metadata for stateless verification of a Bolt12Invoice.
 282                 if $self.refund.payer.0.has_derivation_material() {
 283                         let mut metadata = core::mem::take(&mut $self.refund.payer.0);
 284
 285                         if $self.refund.paths.is_none() {
 286                                 metadata = metadata.without_keys();
 287                         }
 288
 289                         let mut tlv_stream = $self.refund.as_tlv_stream();
 290                         tlv_stream.0.metadata = None;
 291                         if metadata.derives_payer_keys() {
 292                                 tlv_stream.2.payer_id = None;
 293                         }
 294
 295                         let (derived_metadata, keys) = metadata.derive_from(tlv_stream, $self.secp_ctx);
 296                         metadata = derived_metadata;
 297                         if let Some(keys) = keys {
 298                                 $self.refund.payer_id = keys.public_key();
 299                         }
 300
 301                         $self.refund.payer.0 = metadata;
 302                 }
 303
 304                 let mut bytes = Vec::new();
 305                 $self.refund.write(&mut bytes).unwrap();
 306
 307                 Ok(Refund {
 308                         bytes,
 309                         #[cfg(not(c_bindings))]
 310                         contents: $self.refund,
 311                         #[cfg(c_bindings)]
 312                         contents: $self.refund.clone(),
 313                 })
 314         }
 315 } }
 316
 317 #[cfg(test)]
 318 macro_rules! refund_builder_test_methods { (
 319         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr $(, $self_mut: tt)?
 320 ) => {
 321         #[cfg_attr(c_bindings, allow(dead_code))]
 322         pub(crate) fn clear_paths($($self_mut)* $self: $self_type) -> $return_type {
 323                 $self.refund.paths = None;
 324                 $return_value
 325         }
 326
 327         #[cfg_attr(c_bindings, allow(dead_code))]
 328         fn features_unchecked($($self_mut)* $self: $self_type, features: InvoiceRequestFeatures) -> $return_type {
 329                 $self.refund.features = features;
 330                 $return_value
 331         }
 332 } }
 333
 334 impl<'a> RefundBuilder<'a, secp256k1::SignOnly> {
 335         refund_explicit_metadata_builder_methods!();
 336 }
 337
 338 impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
 339         refund_builder_methods!(self, Self, Self, self, T, mut);
 340
 341         #[cfg(test)]
 342         refund_builder_test_methods!(self, Self, Self, self, mut);
 343 }
 344
 345 #[cfg(all(c_bindings, not(test)))]
 346 impl<'a> RefundMaybeWithDerivedMetadataBuilder<'a> {
 347         refund_explicit_metadata_builder_methods!();
 348         refund_builder_methods!(self, &mut Self, (), (), secp256k1::All);
 349 }
 350
 351 #[cfg(all(c_bindings, test))]
 352 impl<'a> RefundMaybeWithDerivedMetadataBuilder<'a> {
 353         refund_explicit_metadata_builder_methods!();
 354         refund_builder_methods!(self, &mut Self, &mut Self, self, secp256k1::All);
 355         refund_builder_test_methods!(self, &mut Self, &mut Self, self);
 356 }
 357
 358 #[cfg(c_bindings)]
 359 impl<'a> From<RefundBuilder<'a, secp256k1::All>>
 360 for RefundMaybeWithDerivedMetadataBuilder<'a> {
 361         fn from(builder: RefundBuilder<'a, secp256k1::All>) -> Self {
 362                 let RefundBuilder { refund, secp_ctx } = builder;
 363
 364                 Self { refund, secp_ctx }
 365         }
 366 }
 367
 368 /// A `Refund` is a request to send an [`Bolt12Invoice`] without a preceding [`Offer`].
 369 ///
 370 /// Typically, after an invoice is paid, the recipient may publish a refund allowing the sender to
 371 /// recoup their funds. A refund may be used more generally as an "offer for money", such as with a
 372 /// bitcoin ATM.
 373 ///
 374 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 375 /// [`Offer`]: crate::offers::offer::Offer
 376 #[derive(Clone, Debug)]
 377 #[cfg_attr(test, derive(PartialEq))]
 378 pub struct Refund {
 379         pub(super) bytes: Vec<u8>,
 380         pub(super) contents: RefundContents,
 381 }
 382
 383 /// The contents of a [`Refund`], which may be shared with an [`Bolt12Invoice`].
 384 ///
 385 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 386 #[derive(Clone, Debug)]
 387 #[cfg_attr(test, derive(PartialEq))]
 388 pub(super) struct RefundContents {
 389         payer: PayerContents,
 390         // offer fields
 391         description: String,
 392         absolute_expiry: Option<Duration>,
 393         issuer: Option<String>,
 394         paths: Option<Vec<BlindedPath>>,
 395         // invoice_request fields
 396         chain: Option<ChainHash>,
 397         amount_msats: u64,
 398         features: InvoiceRequestFeatures,
 399         quantity: Option<u64>,
 400         payer_id: PublicKey,
 401         payer_note: Option<String>,
 402 }
 403
 404 impl Refund {
 405         /// A complete description of the purpose of the refund. Intended to be displayed to the user
 406         /// but with the caveat that it has not been verified in any way.
 407         pub fn description(&self) -> PrintableString {
 408                 self.contents.description()
 409         }
 410
 411         /// Duration since the Unix epoch when an invoice should no longer be sent.
 412         ///
 413         /// If `None`, the refund does not expire.
 414         pub fn absolute_expiry(&self) -> Option<Duration> {
 415                 self.contents.absolute_expiry()
 416         }
 417
 418         /// Whether the refund has expired.
 419         #[cfg(feature = "std")]
 420         pub fn is_expired(&self) -> bool {
 421                 self.contents.is_expired()
 422         }
 423
 424         /// Whether the refund has expired given the duration since the Unix epoch.
 425         pub fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 426                 self.contents.is_expired_no_std(duration_since_epoch)
 427         }
 428
 429         /// The issuer of the refund, possibly beginning with `user@domain` or `domain`. Intended to be
 430         /// displayed to the user but with the caveat that it has not been verified in any way.
 431         pub fn issuer(&self) -> Option<PrintableString> {
 432                 self.contents.issuer()
 433         }
 434
 435         /// Paths to the sender originating from publicly reachable nodes. Blinded paths provide sender
 436         /// privacy by obfuscating its node id.
 437         pub fn paths(&self) -> &[BlindedPath] {
 438                 self.contents.paths()
 439         }
 440
 441         /// An unpredictable series of bytes, typically containing information about the derivation of
 442         /// [`payer_id`].
 443         ///
 444         /// [`payer_id`]: Self::payer_id
 445         pub fn payer_metadata(&self) -> &[u8] {
 446                 self.contents.metadata()
 447         }
 448
 449         /// A chain that the refund is valid for.
 450         pub fn chain(&self) -> ChainHash {
 451                 self.contents.chain()
 452         }
 453
 454         /// The amount to refund in msats (i.e., the minimum lightning-payable unit for [`chain`]).
 455         ///
 456         /// [`chain`]: Self::chain
 457         pub fn amount_msats(&self) -> u64 {
 458                 self.contents.amount_msats()
 459         }
 460
 461         /// Features pertaining to requesting an invoice.
 462         pub fn features(&self) -> &InvoiceRequestFeatures {
 463                 &self.contents.features()
 464         }
 465
 466         /// The quantity of an item that refund is for.
 467         pub fn quantity(&self) -> Option<u64> {
 468                 self.contents.quantity()
 469         }
 470
 471         /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
 472         /// transient pubkey.
 473         ///
 474         /// [`paths`]: Self::paths
 475         pub fn payer_id(&self) -> PublicKey {
 476                 self.contents.payer_id()
 477         }
 478
 479         /// Payer provided note to include in the invoice.
 480         pub fn payer_note(&self) -> Option<PrintableString> {
 481                 self.contents.payer_note()
 482         }
 483 }
 484
 485 macro_rules! respond_with_explicit_signing_pubkey_methods { ($self: ident, $builder: ty) => {
 486         /// Creates an [`InvoiceBuilder`] for the refund with the given required fields and using the
 487         /// [`Duration`] since [`std::time::SystemTime::UNIX_EPOCH`] as the creation time.
 488         ///
 489         /// See [`Refund::respond_with_no_std`] for further details where the aforementioned creation
 490         /// time is used for the `created_at` parameter.
 491         ///
 492         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 493         ///
 494         /// [`Duration`]: core::time::Duration
 495         #[cfg(feature = "std")]
 496         pub fn respond_with(
 497                 &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 498                 signing_pubkey: PublicKey,
 499         ) -> Result<$builder, Bolt12SemanticError> {
 500                 let created_at = std::time::SystemTime::now()
 501                         .duration_since(std::time::SystemTime::UNIX_EPOCH)
 502                         .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 503
 504                 $self.respond_with_no_std(payment_paths, payment_hash, signing_pubkey, created_at)
 505         }
 506
 507         /// Creates an [`InvoiceBuilder`] for the refund with the given required fields.
 508         ///
 509         /// Unless [`InvoiceBuilder::relative_expiry`] is set, the invoice will expire two hours after
 510         /// `created_at`, which is used to set [`Bolt12Invoice::created_at`]. Useful for `no-std` builds
 511         /// where [`std::time::SystemTime`] is not available.
 512         ///
 513         /// The caller is expected to remember the preimage of `payment_hash` in order to
 514         /// claim a payment for the invoice.
 515         ///
 516         /// The `signing_pubkey` is required to sign the invoice since refunds are not in response to an
 517         /// offer, which does have a `signing_pubkey`.
 518         ///
 519         /// The `payment_paths` parameter is useful for maintaining the payment recipient's privacy. It
 520         /// must contain one or more elements ordered from most-preferred to least-preferred, if there's
 521         /// a preference. Note, however, that any privacy is lost if a public node id is used for
 522         /// `signing_pubkey`.
 523         ///
 524         /// Errors if the request contains unknown required features.
 525         ///
 526         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 527         ///
 528         /// [`Bolt12Invoice::created_at`]: crate::offers::invoice::Bolt12Invoice::created_at
 529         pub fn respond_with_no_std(
 530                 &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 531                 signing_pubkey: PublicKey, created_at: Duration
 532         ) -> Result<$builder, Bolt12SemanticError> {
 533                 if $self.features().requires_unknown_bits() {
 534                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 535                 }
 536
 537                 <$builder>::for_refund($self, payment_paths, created_at, payment_hash, signing_pubkey)
 538         }
 539 } }
 540
 541 macro_rules! respond_with_derived_signing_pubkey_methods { ($self: ident, $builder: ty) => {
 542         /// Creates an [`InvoiceBuilder`] for the refund using the given required fields and that uses
 543         /// derived signing keys to sign the [`Bolt12Invoice`].
 544         ///
 545         /// See [`Refund::respond_with`] for further details.
 546         ///
 547         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 548         ///
 549         /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 550         #[cfg(feature = "std")]
 551         pub fn respond_using_derived_keys<ES: Deref>(
 552                 &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 553                 expanded_key: &ExpandedKey, entropy_source: ES
 554         ) -> Result<$builder, Bolt12SemanticError>
 555         where
 556                 ES::Target: EntropySource,
 557         {
 558                 let created_at = std::time::SystemTime::now()
 559                         .duration_since(std::time::SystemTime::UNIX_EPOCH)
 560                         .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 561
 562                 $self.respond_using_derived_keys_no_std(
 563                         payment_paths, payment_hash, created_at, expanded_key, entropy_source
 564                 )
 565         }
 566
 567         /// Creates an [`InvoiceBuilder`] for the refund using the given required fields and that uses
 568         /// derived signing keys to sign the [`Bolt12Invoice`].
 569         ///
 570         /// See [`Refund::respond_with_no_std`] for further details.
 571         ///
 572         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 573         ///
 574         /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 575         pub fn respond_using_derived_keys_no_std<ES: Deref>(
 576                 &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 577                 created_at: core::time::Duration, expanded_key: &ExpandedKey, entropy_source: ES
 578         ) -> Result<$builder, Bolt12SemanticError>
 579         where
 580                 ES::Target: EntropySource,
 581         {
 582                 if $self.features().requires_unknown_bits() {
 583                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 584                 }
 585
 586                 let nonce = Nonce::from_entropy_source(entropy_source);
 587                 let keys = signer::derive_keys(nonce, expanded_key);
 588                 <$builder>::for_refund_using_keys($self, payment_paths, created_at, payment_hash, keys)
 589         }
 590 } }
 591
 592 impl Refund {
 593         respond_with_explicit_signing_pubkey_methods!(self, InvoiceBuilder<ExplicitSigningPubkey>);
 594         respond_with_derived_signing_pubkey_methods!(self, InvoiceBuilder<DerivedSigningPubkey>);
 595 }
 596
 597 #[cfg(test)]
 598 impl Refund {
 599         fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 600                 self.contents.as_tlv_stream()
 601         }
 602 }
 603
 604 impl AsRef<[u8]> for Refund {
 605         fn as_ref(&self) -> &[u8] {
 606                 &self.bytes
 607         }
 608 }
 609
 610 impl RefundContents {
 611         pub fn description(&self) -> PrintableString {
 612                 PrintableString(&self.description)
 613         }
 614
 615         pub fn absolute_expiry(&self) -> Option<Duration> {
 616                 self.absolute_expiry
 617         }
 618
 619         #[cfg(feature = "std")]
 620         pub(super) fn is_expired(&self) -> bool {
 621                 SystemTime::UNIX_EPOCH
 622                         .elapsed()
 623                         .map(|duration_since_epoch| self.is_expired_no_std(duration_since_epoch))
 624                         .unwrap_or(false)
 625         }
 626
 627         pub(super) fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 628                 self.absolute_expiry
 629                         .map(|absolute_expiry| duration_since_epoch > absolute_expiry)
 630                         .unwrap_or(false)
 631         }
 632
 633         pub fn issuer(&self) -> Option<PrintableString> {
 634                 self.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 635         }
 636
 637         pub fn paths(&self) -> &[BlindedPath] {
 638                 self.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 639         }
 640
 641         pub(super) fn metadata(&self) -> &[u8] {
 642                 self.payer.0.as_bytes().map(|bytes| bytes.as_slice()).unwrap_or(&[])
 643         }
 644
 645         pub(super) fn chain(&self) -> ChainHash {
 646                 self.chain.unwrap_or_else(|| self.implied_chain())
 647         }
 648
 649         pub fn implied_chain(&self) -> ChainHash {
 650                 ChainHash::using_genesis_block(Network::Bitcoin)
 651         }
 652
 653         pub fn amount_msats(&self) -> u64 {
 654                 self.amount_msats
 655         }
 656
 657         /// Features pertaining to requesting an invoice.
 658         pub fn features(&self) -> &InvoiceRequestFeatures {
 659                 &self.features
 660         }
 661
 662         /// The quantity of an item that refund is for.
 663         pub fn quantity(&self) -> Option<u64> {
 664                 self.quantity
 665         }
 666
 667         /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
 668         /// transient pubkey.
 669         ///
 670         /// [`paths`]: Self::paths
 671         pub fn payer_id(&self) -> PublicKey {
 672                 self.payer_id
 673         }
 674
 675         /// Payer provided note to include in the invoice.
 676         pub fn payer_note(&self) -> Option<PrintableString> {
 677                 self.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
 678         }
 679
 680         pub(super) fn derives_keys(&self) -> bool {
 681                 self.payer.0.derives_payer_keys()
 682         }
 683
 684         pub(super) fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 685                 let payer = PayerTlvStreamRef {
 686                         metadata: self.payer.0.as_bytes(),
 687                 };
 688
 689                 let offer = OfferTlvStreamRef {
 690                         chains: None,
 691                         metadata: None,
 692                         currency: None,
 693                         amount: None,
 694                         description: Some(&self.description),
 695                         features: None,
 696                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 697                         paths: self.paths.as_ref(),
 698                         issuer: self.issuer.as_ref(),
 699                         quantity_max: None,
 700                         node_id: None,
 701                 };
 702
 703                 let features = {
 704                         if self.features == InvoiceRequestFeatures::empty() { None }
 705                         else { Some(&self.features) }
 706                 };
 707
 708                 let invoice_request = InvoiceRequestTlvStreamRef {
 709                         chain: self.chain.as_ref(),
 710                         amount: Some(self.amount_msats),
 711                         features,
 712                         quantity: self.quantity,
 713                         payer_id: Some(&self.payer_id),
 714                         payer_note: self.payer_note.as_ref(),
 715                 };
 716
 717                 (payer, offer, invoice_request)
 718         }
 719 }
 720
 721 impl Writeable for Refund {
 722         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 723                 WithoutLength(&self.bytes).write(writer)
 724         }
 725 }
 726
 727 impl Writeable for RefundContents {
 728         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 729                 self.as_tlv_stream().write(writer)
 730         }
 731 }
 732
 733 type RefundTlvStream = (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream);
 734
 735 type RefundTlvStreamRef<'a> = (
 736         PayerTlvStreamRef<'a>,
 737         OfferTlvStreamRef<'a>,
 738         InvoiceRequestTlvStreamRef<'a>,
 739 );
 740
 741 impl SeekReadable for RefundTlvStream {
 742         fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
 743                 let payer = SeekReadable::read(r)?;
 744                 let offer = SeekReadable::read(r)?;
 745                 let invoice_request = SeekReadable::read(r)?;
 746
 747                 Ok((payer, offer, invoice_request))
 748         }
 749 }
 750
 751 impl Bech32Encode for Refund {
 752         const BECH32_HRP: &'static str = "lnr";
 753 }
 754
 755 impl FromStr for Refund {
 756         type Err = Bolt12ParseError;
 757
 758         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 759                 Refund::from_bech32_str(s)
 760         }
 761 }
 762
 763 impl TryFrom<Vec<u8>> for Refund {
 764         type Error = Bolt12ParseError;
 765
 766         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 767                 let refund = ParsedMessage::<RefundTlvStream>::try_from(bytes)?;
 768                 let ParsedMessage { bytes, tlv_stream } = refund;
 769                 let contents = RefundContents::try_from(tlv_stream)?;
 770
 771                 Ok(Refund { bytes, contents })
 772         }
 773 }
 774
 775 impl TryFrom<RefundTlvStream> for RefundContents {
 776         type Error = Bolt12SemanticError;
 777
 778         fn try_from(tlv_stream: RefundTlvStream) -> Result<Self, Self::Error> {
 779                 let (
 780                         PayerTlvStream { metadata: payer_metadata },
 781                         OfferTlvStream {
 782                                 chains, metadata, currency, amount: offer_amount, description,
 783                                 features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
 784                         },
 785                         InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
 786                 ) = tlv_stream;
 787
 788                 let payer = match payer_metadata {
 789                         None => return Err(Bolt12SemanticError::MissingPayerMetadata),
 790                         Some(metadata) => PayerContents(Metadata::Bytes(metadata)),
 791                 };
 792
 793                 if metadata.is_some() {
 794                         return Err(Bolt12SemanticError::UnexpectedMetadata);
 795                 }
 796
 797                 if chains.is_some() {
 798                         return Err(Bolt12SemanticError::UnexpectedChain);
 799                 }
 800
 801                 if currency.is_some() || offer_amount.is_some() {
 802                         return Err(Bolt12SemanticError::UnexpectedAmount);
 803                 }
 804
 805                 let description = match description {
 806                         None => return Err(Bolt12SemanticError::MissingDescription),
 807                         Some(description) => description,
 808                 };
 809
 810                 if offer_features.is_some() {
 811                         return Err(Bolt12SemanticError::UnexpectedFeatures);
 812                 }
 813
 814                 let absolute_expiry = absolute_expiry.map(Duration::from_secs);
 815
 816                 if quantity_max.is_some() {
 817                         return Err(Bolt12SemanticError::UnexpectedQuantity);
 818                 }
 819
 820                 if node_id.is_some() {
 821                         return Err(Bolt12SemanticError::UnexpectedSigningPubkey);
 822                 }
 823
 824                 let amount_msats = match amount {
 825                         None => return Err(Bolt12SemanticError::MissingAmount),
 826                         Some(amount_msats) if amount_msats > MAX_VALUE_MSAT => {
 827                                 return Err(Bolt12SemanticError::InvalidAmount);
 828                         },
 829                         Some(amount_msats) => amount_msats,
 830                 };
 831
 832                 let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
 833
 834                 let payer_id = match payer_id {
 835                         None => return Err(Bolt12SemanticError::MissingPayerId),
 836                         Some(payer_id) => payer_id,
 837                 };
 838
 839                 Ok(RefundContents {
 840                         payer, description, absolute_expiry, issuer, paths, chain, amount_msats, features,
 841                         quantity, payer_id, payer_note,
 842                 })
 843         }
 844 }
 845
 846 impl core::fmt::Display for Refund {
 847         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 848                 self.fmt_bech32_str(f)
 849         }
 850 }
 851
 852 #[cfg(test)]
 853 mod tests {
 854         use super::{Refund, RefundTlvStreamRef};
 855         #[cfg(not(c_bindings))]
 856         use {
 857                 super::RefundBuilder,
 858         };
 859         #[cfg(c_bindings)]
 860         use {
 861                 super::RefundMaybeWithDerivedMetadataBuilder as RefundBuilder,
 862         };
 863
 864         use bitcoin::blockdata::constants::ChainHash;
 865         use bitcoin::network::constants::Network;
 866         use bitcoin::secp256k1::{KeyPair, Secp256k1, SecretKey};
 867         use core::convert::TryFrom;
 868         use core::time::Duration;
 869         use crate::blinded_path::{BlindedHop, BlindedPath};
 870         use crate::sign::KeyMaterial;
 871         use crate::ln::channelmanager::PaymentId;
 872         use crate::ln::features::{InvoiceRequestFeatures, OfferFeatures};
 873         use crate::ln::inbound_payment::ExpandedKey;
 874         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 875         use crate::offers::invoice_request::InvoiceRequestTlvStreamRef;
 876         use crate::offers::offer::OfferTlvStreamRef;
 877         use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
 878         use crate::offers::payer::PayerTlvStreamRef;
 879         use crate::offers::test_utils::*;
 880         use crate::util::ser::{BigSize, Writeable};
 881         use crate::util::string::PrintableString;
 882
 883         trait ToBytes {
 884                 fn to_bytes(&self) -> Vec<u8>;
 885         }
 886
 887         impl<'a> ToBytes for RefundTlvStreamRef<'a> {
 888                 fn to_bytes(&self) -> Vec<u8> {
 889                         let mut buffer = Vec::new();
 890                         self.write(&mut buffer).unwrap();
 891                         buffer
 892                 }
 893         }
 894
 895         #[test]
 896         fn builds_refund_with_defaults() {
 897                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 898                         .build().unwrap();
 899
 900                 let mut buffer = Vec::new();
 901                 refund.write(&mut buffer).unwrap();
 902
 903                 assert_eq!(refund.bytes, buffer.as_slice());
 904                 assert_eq!(refund.payer_metadata(), &[1; 32]);
 905                 assert_eq!(refund.description(), PrintableString("foo"));
 906                 assert_eq!(refund.absolute_expiry(), None);
 907                 #[cfg(feature = "std")]
 908                 assert!(!refund.is_expired());
 909                 assert_eq!(refund.paths(), &[]);
 910                 assert_eq!(refund.issuer(), None);
 911                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Bitcoin));
 912                 assert_eq!(refund.amount_msats(), 1000);
 913                 assert_eq!(refund.features(), &InvoiceRequestFeatures::empty());
 914                 assert_eq!(refund.payer_id(), payer_pubkey());
 915                 assert_eq!(refund.payer_note(), None);
 916
 917                 assert_eq!(
 918                         refund.as_tlv_stream(),
 919                         (
 920                                 PayerTlvStreamRef { metadata: Some(&vec![1; 32]) },
 921                                 OfferTlvStreamRef {
 922                                         chains: None,
 923                                         metadata: None,
 924                                         currency: None,
 925                                         amount: None,
 926                                         description: Some(&String::from("foo")),
 927                                         features: None,
 928                                         absolute_expiry: None,
 929                                         paths: None,
 930                                         issuer: None,
 931                                         quantity_max: None,
 932                                         node_id: None,
 933                                 },
 934                                 InvoiceRequestTlvStreamRef {
 935                                         chain: None,
 936                                         amount: Some(1000),
 937                                         features: None,
 938                                         quantity: None,
 939                                         payer_id: Some(&payer_pubkey()),
 940                                         payer_note: None,
 941                                 },
 942                         ),
 943                 );
 944
 945                 if let Err(e) = Refund::try_from(buffer) {
 946                         panic!("error parsing refund: {:?}", e);
 947                 }
 948         }
 949
 950         #[test]
 951         fn fails_building_refund_with_invalid_amount() {
 952                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), MAX_VALUE_MSAT + 1) {
 953                         Ok(_) => panic!("expected error"),
 954                         Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
 955                 }
 956         }
 957
 958         #[test]
 959         fn builds_refund_with_metadata_derived() {
 960                 let desc = "foo".to_string();
 961                 let node_id = payer_pubkey();
 962                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
 963                 let entropy = FixedEntropy {};
 964                 let secp_ctx = Secp256k1::new();
 965                 let payment_id = PaymentId([1; 32]);
 966
 967                 let refund = RefundBuilder
 968                         ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
 969                         .unwrap()
 970                         .build().unwrap();
 971                 assert_eq!(refund.payer_id(), node_id);
 972
 973                 // Fails verification with altered fields
 974                 let invoice = refund
 975                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
 976                         .unwrap()
 977                         .build().unwrap()
 978                         .sign(recipient_sign).unwrap();
 979                 match invoice.verify(&expanded_key, &secp_ctx) {
 980                         Ok(payment_id) => assert_eq!(payment_id, PaymentId([1; 32])),
 981                         Err(()) => panic!("verification failed"),
 982                 }
 983
 984                 let mut tlv_stream = refund.as_tlv_stream();
 985                 tlv_stream.2.amount = Some(2000);
 986
 987                 let mut encoded_refund = Vec::new();
 988                 tlv_stream.write(&mut encoded_refund).unwrap();
 989
 990                 let invoice = Refund::try_from(encoded_refund).unwrap()
 991                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
 992                         .unwrap()
 993                         .build().unwrap()
 994                         .sign(recipient_sign).unwrap();
 995                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
 996
 997                 // Fails verification with altered metadata
 998                 let mut tlv_stream = refund.as_tlv_stream();
 999                 let metadata = tlv_stream.0.metadata.unwrap().iter().copied().rev().collect();
1000                 tlv_stream.0.metadata = Some(&metadata);
1001
1002                 let mut encoded_refund = Vec::new();
1003                 tlv_stream.write(&mut encoded_refund).unwrap();
1004
1005                 let invoice = Refund::try_from(encoded_refund).unwrap()
1006                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1007                         .unwrap()
1008                         .build().unwrap()
1009                         .sign(recipient_sign).unwrap();
1010                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
1011         }
1012
1013         #[test]
1014         fn builds_refund_with_derived_payer_id() {
1015                 let desc = "foo".to_string();
1016                 let node_id = payer_pubkey();
1017                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1018                 let entropy = FixedEntropy {};
1019                 let secp_ctx = Secp256k1::new();
1020                 let payment_id = PaymentId([1; 32]);
1021
1022                 let blinded_path = BlindedPath {
1023                         introduction_node_id: pubkey(40),
1024                         blinding_point: pubkey(41),
1025                         blinded_hops: vec![
1026                                 BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1027                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
1028                         ],
1029                 };
1030
1031                 let refund = RefundBuilder
1032                         ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
1033                         .unwrap()
1034                         .path(blinded_path)
1035                         .build().unwrap();
1036                 assert_ne!(refund.payer_id(), node_id);
1037
1038                 let invoice = refund
1039                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1040                         .unwrap()
1041                         .build().unwrap()
1042                         .sign(recipient_sign).unwrap();
1043                 match invoice.verify(&expanded_key, &secp_ctx) {
1044                         Ok(payment_id) => assert_eq!(payment_id, PaymentId([1; 32])),
1045                         Err(()) => panic!("verification failed"),
1046                 }
1047
1048                 // Fails verification with altered fields
1049                 let mut tlv_stream = refund.as_tlv_stream();
1050                 tlv_stream.2.amount = Some(2000);
1051
1052                 let mut encoded_refund = Vec::new();
1053                 tlv_stream.write(&mut encoded_refund).unwrap();
1054
1055                 let invoice = Refund::try_from(encoded_refund).unwrap()
1056                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1057                         .unwrap()
1058                         .build().unwrap()
1059                         .sign(recipient_sign).unwrap();
1060                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
1061
1062                 // Fails verification with altered payer_id
1063                 let mut tlv_stream = refund.as_tlv_stream();
1064                 let payer_id = pubkey(1);
1065                 tlv_stream.2.payer_id = Some(&payer_id);
1066
1067                 let mut encoded_refund = Vec::new();
1068                 tlv_stream.write(&mut encoded_refund).unwrap();
1069
1070                 let invoice = Refund::try_from(encoded_refund).unwrap()
1071                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1072                         .unwrap()
1073                         .build().unwrap()
1074                         .sign(recipient_sign).unwrap();
1075                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
1076         }
1077
1078         #[test]
1079         fn builds_refund_with_absolute_expiry() {
1080                 let future_expiry = Duration::from_secs(u64::max_value());
1081                 let past_expiry = Duration::from_secs(0);
1082                 let now = future_expiry - Duration::from_secs(1_000);
1083
1084                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1085                         .absolute_expiry(future_expiry)
1086                         .build()
1087                         .unwrap();
1088                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1089                 #[cfg(feature = "std")]
1090                 assert!(!refund.is_expired());
1091                 assert!(!refund.is_expired_no_std(now));
1092                 assert_eq!(refund.absolute_expiry(), Some(future_expiry));
1093                 assert_eq!(tlv_stream.absolute_expiry, Some(future_expiry.as_secs()));
1094
1095                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1096                         .absolute_expiry(future_expiry)
1097                         .absolute_expiry(past_expiry)
1098                         .build()
1099                         .unwrap();
1100                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1101                 #[cfg(feature = "std")]
1102                 assert!(refund.is_expired());
1103                 assert!(refund.is_expired_no_std(now));
1104                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
1105                 assert_eq!(tlv_stream.absolute_expiry, Some(past_expiry.as_secs()));
1106         }
1107
1108         #[test]
1109         fn builds_refund_with_paths() {
1110                 let paths = vec![
1111                         BlindedPath {
1112                                 introduction_node_id: pubkey(40),
1113                                 blinding_point: pubkey(41),
1114                                 blinded_hops: vec![
1115                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1116                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1117                                 ],
1118                         },
1119                         BlindedPath {
1120                                 introduction_node_id: pubkey(40),
1121                                 blinding_point: pubkey(41),
1122                                 blinded_hops: vec![
1123                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1124                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1125                                 ],
1126                         },
1127                 ];
1128
1129                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1130                         .path(paths[0].clone())
1131                         .path(paths[1].clone())
1132                         .build()
1133                         .unwrap();
1134                 let (_, offer_tlv_stream, invoice_request_tlv_stream) = refund.as_tlv_stream();
1135                 assert_eq!(refund.paths(), paths.as_slice());
1136                 assert_eq!(refund.payer_id(), pubkey(42));
1137                 assert_ne!(pubkey(42), pubkey(44));
1138                 assert_eq!(offer_tlv_stream.paths, Some(&paths));
1139                 assert_eq!(invoice_request_tlv_stream.payer_id, Some(&pubkey(42)));
1140         }
1141
1142         #[test]
1143         fn builds_refund_with_issuer() {
1144                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1145                         .issuer("bar".into())
1146                         .build()
1147                         .unwrap();
1148                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1149                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
1150                 assert_eq!(tlv_stream.issuer, Some(&String::from("bar")));
1151
1152                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1153                         .issuer("bar".into())
1154                         .issuer("baz".into())
1155                         .build()
1156                         .unwrap();
1157                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1158                 assert_eq!(refund.issuer(), Some(PrintableString("baz")));
1159                 assert_eq!(tlv_stream.issuer, Some(&String::from("baz")));
1160         }
1161
1162         #[test]
1163         fn builds_refund_with_chain() {
1164                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
1165                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
1166
1167                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1168                         .chain(Network::Bitcoin)
1169                         .build().unwrap();
1170                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1171                 assert_eq!(refund.chain(), mainnet);
1172                 assert_eq!(tlv_stream.chain, None);
1173
1174                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1175                         .chain(Network::Testnet)
1176                         .build().unwrap();
1177                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1178                 assert_eq!(refund.chain(), testnet);
1179                 assert_eq!(tlv_stream.chain, Some(&testnet));
1180
1181                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1182                         .chain(Network::Regtest)
1183                         .chain(Network::Testnet)
1184                         .build().unwrap();
1185                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1186                 assert_eq!(refund.chain(), testnet);
1187                 assert_eq!(tlv_stream.chain, Some(&testnet));
1188         }
1189
1190         #[test]
1191         fn builds_refund_with_quantity() {
1192                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1193                         .quantity(10)
1194                         .build().unwrap();
1195                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1196                 assert_eq!(refund.quantity(), Some(10));
1197                 assert_eq!(tlv_stream.quantity, Some(10));
1198
1199                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1200                         .quantity(10)
1201                         .quantity(1)
1202                         .build().unwrap();
1203                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1204                 assert_eq!(refund.quantity(), Some(1));
1205                 assert_eq!(tlv_stream.quantity, Some(1));
1206         }
1207
1208         #[test]
1209         fn builds_refund_with_payer_note() {
1210                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1211                         .payer_note("bar".into())
1212                         .build().unwrap();
1213                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1214                 assert_eq!(refund.payer_note(), Some(PrintableString("bar")));
1215                 assert_eq!(tlv_stream.payer_note, Some(&String::from("bar")));
1216
1217                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1218                         .payer_note("bar".into())
1219                         .payer_note("baz".into())
1220                         .build().unwrap();
1221                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1222                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
1223                 assert_eq!(tlv_stream.payer_note, Some(&String::from("baz")));
1224         }
1225
1226         #[test]
1227         fn fails_responding_with_unknown_required_features() {
1228                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1229                         .features_unchecked(InvoiceRequestFeatures::unknown())
1230                         .build().unwrap()
1231                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1232                 {
1233                         Ok(_) => panic!("expected error"),
1234                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnknownRequiredFeatures),
1235                 }
1236         }
1237
1238         #[test]
1239         fn parses_refund_with_metadata() {
1240                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1241                         .build().unwrap();
1242                 if let Err(e) = refund.to_string().parse::<Refund>() {
1243                         panic!("error parsing refund: {:?}", e);
1244                 }
1245
1246                 let mut tlv_stream = refund.as_tlv_stream();
1247                 tlv_stream.0.metadata = None;
1248
1249                 match Refund::try_from(tlv_stream.to_bytes()) {
1250                         Ok(_) => panic!("expected error"),
1251                         Err(e) => {
1252                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingPayerMetadata));
1253                         },
1254                 }
1255         }
1256
1257         #[test]
1258         fn parses_refund_with_description() {
1259                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1260                         .build().unwrap();
1261                 if let Err(e) = refund.to_string().parse::<Refund>() {
1262                         panic!("error parsing refund: {:?}", e);
1263                 }
1264
1265                 let mut tlv_stream = refund.as_tlv_stream();
1266                 tlv_stream.1.description = None;
1267
1268                 match Refund::try_from(tlv_stream.to_bytes()) {
1269                         Ok(_) => panic!("expected error"),
1270                         Err(e) => {
1271                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription));
1272                         },
1273                 }
1274         }
1275
1276         #[test]
1277         fn parses_refund_with_amount() {
1278                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1279                         .build().unwrap();
1280                 if let Err(e) = refund.to_string().parse::<Refund>() {
1281                         panic!("error parsing refund: {:?}", e);
1282                 }
1283
1284                 let mut tlv_stream = refund.as_tlv_stream();
1285                 tlv_stream.2.amount = None;
1286
1287                 match Refund::try_from(tlv_stream.to_bytes()) {
1288                         Ok(_) => panic!("expected error"),
1289                         Err(e) => {
1290                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingAmount));
1291                         },
1292                 }
1293
1294                 let mut tlv_stream = refund.as_tlv_stream();
1295                 tlv_stream.2.amount = Some(MAX_VALUE_MSAT + 1);
1296
1297                 match Refund::try_from(tlv_stream.to_bytes()) {
1298                         Ok(_) => panic!("expected error"),
1299                         Err(e) => {
1300                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InvalidAmount));
1301                         },
1302                 }
1303         }
1304
1305         #[test]
1306         fn parses_refund_with_payer_id() {
1307                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1308                         .build().unwrap();
1309                 if let Err(e) = refund.to_string().parse::<Refund>() {
1310                         panic!("error parsing refund: {:?}", e);
1311                 }
1312
1313                 let mut tlv_stream = refund.as_tlv_stream();
1314                 tlv_stream.2.payer_id = None;
1315
1316                 match Refund::try_from(tlv_stream.to_bytes()) {
1317                         Ok(_) => panic!("expected error"),
1318                         Err(e) => {
1319                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingPayerId));
1320                         },
1321                 }
1322         }
1323
1324         #[test]
1325         fn parses_refund_with_optional_fields() {
1326                 let past_expiry = Duration::from_secs(0);
1327                 let paths = vec![
1328                         BlindedPath {
1329                                 introduction_node_id: pubkey(40),
1330                                 blinding_point: pubkey(41),
1331                                 blinded_hops: vec![
1332                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1333                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1334                                 ],
1335                         },
1336                         BlindedPath {
1337                                 introduction_node_id: pubkey(40),
1338                                 blinding_point: pubkey(41),
1339                                 blinded_hops: vec![
1340                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1341                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1342                                 ],
1343                         },
1344                 ];
1345
1346                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1347                         .absolute_expiry(past_expiry)
1348                         .issuer("bar".into())
1349                         .path(paths[0].clone())
1350                         .path(paths[1].clone())
1351                         .chain(Network::Testnet)
1352                         .features_unchecked(InvoiceRequestFeatures::unknown())
1353                         .quantity(10)
1354                         .payer_note("baz".into())
1355                         .build()
1356                         .unwrap();
1357                 match refund.to_string().parse::<Refund>() {
1358                         Ok(refund) => {
1359                                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
1360                                 #[cfg(feature = "std")]
1361                                 assert!(refund.is_expired());
1362                                 assert_eq!(refund.paths(), &paths[..]);
1363                                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
1364                                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Testnet));
1365                                 assert_eq!(refund.features(), &InvoiceRequestFeatures::unknown());
1366                                 assert_eq!(refund.quantity(), Some(10));
1367                                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
1368                         },
1369                         Err(e) => panic!("error parsing refund: {:?}", e),
1370                 }
1371         }
1372
1373         #[test]
1374         fn fails_parsing_refund_with_unexpected_fields() {
1375                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1376                         .build().unwrap();
1377                 if let Err(e) = refund.to_string().parse::<Refund>() {
1378                         panic!("error parsing refund: {:?}", e);
1379                 }
1380
1381                 let metadata = vec![42; 32];
1382                 let mut tlv_stream = refund.as_tlv_stream();
1383                 tlv_stream.1.metadata = Some(&metadata);
1384
1385                 match Refund::try_from(tlv_stream.to_bytes()) {
1386                         Ok(_) => panic!("expected error"),
1387                         Err(e) => {
1388                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedMetadata));
1389                         },
1390                 }
1391
1392                 let chains = vec![ChainHash::using_genesis_block(Network::Testnet)];
1393                 let mut tlv_stream = refund.as_tlv_stream();
1394                 tlv_stream.1.chains = Some(&chains);
1395
1396                 match Refund::try_from(tlv_stream.to_bytes()) {
1397                         Ok(_) => panic!("expected error"),
1398                         Err(e) => {
1399                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedChain));
1400                         },
1401                 }
1402
1403                 let mut tlv_stream = refund.as_tlv_stream();
1404                 tlv_stream.1.currency = Some(&b"USD");
1405                 tlv_stream.1.amount = Some(1000);
1406
1407                 match Refund::try_from(tlv_stream.to_bytes()) {
1408                         Ok(_) => panic!("expected error"),
1409                         Err(e) => {
1410                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedAmount));
1411                         },
1412                 }
1413
1414                 let features = OfferFeatures::unknown();
1415                 let mut tlv_stream = refund.as_tlv_stream();
1416                 tlv_stream.1.features = Some(&features);
1417
1418                 match Refund::try_from(tlv_stream.to_bytes()) {
1419                         Ok(_) => panic!("expected error"),
1420                         Err(e) => {
1421                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedFeatures));
1422                         },
1423                 }
1424
1425                 let mut tlv_stream = refund.as_tlv_stream();
1426                 tlv_stream.1.quantity_max = Some(10);
1427
1428                 match Refund::try_from(tlv_stream.to_bytes()) {
1429                         Ok(_) => panic!("expected error"),
1430                         Err(e) => {
1431                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedQuantity));
1432                         },
1433                 }
1434
1435                 let node_id = payer_pubkey();
1436                 let mut tlv_stream = refund.as_tlv_stream();
1437                 tlv_stream.1.node_id = Some(&node_id);
1438
1439                 match Refund::try_from(tlv_stream.to_bytes()) {
1440                         Ok(_) => panic!("expected error"),
1441                         Err(e) => {
1442                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedSigningPubkey));
1443                         },
1444                 }
1445         }
1446
1447         #[test]
1448         fn fails_parsing_refund_with_extra_tlv_records() {
1449                 let secp_ctx = Secp256k1::new();
1450                 let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
1451                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], keys.public_key(), 1000).unwrap()
1452                         .build().unwrap();
1453
1454                 let mut encoded_refund = Vec::new();
1455                 refund.write(&mut encoded_refund).unwrap();
1456                 BigSize(1002).write(&mut encoded_refund).unwrap();
1457                 BigSize(32).write(&mut encoded_refund).unwrap();
1458                 [42u8; 32].write(&mut encoded_refund).unwrap();
1459
1460                 match Refund::try_from(encoded_refund) {
1461                         Ok(_) => panic!("expected error"),
1462                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1463                 }
1464         }
1465 }