_ 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;
 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 #[cfg(not(c_bindings))]
 109 use {
 110         crate::offers::invoice::{DerivedSigningPubkey, ExplicitSigningPubkey, InvoiceBuilder},
 111 };
 112 #[cfg(c_bindings)]
 113 use {
 114         crate::offers::invoice::{InvoiceWithDerivedSigningPubkeyBuilder, InvoiceWithExplicitSigningPubkeyBuilder},
 115 };
 116
 117 use crate::prelude::*;
 118
 119 #[cfg(feature = "std")]
 120 use std::time::SystemTime;
 121
 122 pub(super) const IV_BYTES: &[u8; IV_LEN] = b"LDK Refund ~~~~~";
 123
 124 /// Builds a [`Refund`] for the "offer for money" flow.
 125 ///
 126 /// See [module-level documentation] for usage.
 127 ///
 128 /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 129 ///
 130 /// [module-level documentation]: self
 131 pub struct RefundBuilder<'a, T: secp256k1::Signing> {
 132         refund: RefundContents,
 133         secp_ctx: Option<&'a Secp256k1<T>>,
 134 }
 135
 136 /// Builds a [`Refund`] for the "offer for money" flow.
 137 ///
 138 /// See [module-level documentation] for usage.
 139 ///
 140 /// [module-level documentation]: self
 141 #[cfg(c_bindings)]
 142 pub struct RefundMaybeWithDerivedMetadataBuilder<'a> {
 143         refund: RefundContents,
 144         secp_ctx: Option<&'a Secp256k1<secp256k1::All>>,
 145 }
 146
 147 macro_rules! refund_explicit_metadata_builder_methods { () => {
 148         /// Creates a new builder for a refund using the [`Refund::payer_id`] for the public node id to
 149         /// send to if no [`Refund::paths`] are set. Otherwise, it may be a transient pubkey.
 150         ///
 151         /// Additionally, sets the required [`Refund::description`], [`Refund::payer_metadata`], and
 152         /// [`Refund::amount_msats`].
 153         ///
 154         /// # Note
 155         ///
 156         /// If constructing a [`Refund`] for use with a [`ChannelManager`], use
 157         /// [`ChannelManager::create_refund_builder`] instead of [`RefundBuilder::new`].
 158         ///
 159         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 160         /// [`ChannelManager::create_refund_builder`]: crate::ln::channelmanager::ChannelManager::create_refund_builder
 161         pub fn new(
 162                 description: String, metadata: Vec<u8>, payer_id: PublicKey, amount_msats: u64
 163         ) -> Result<Self, Bolt12SemanticError> {
 164                 if amount_msats > MAX_VALUE_MSAT {
 165                         return Err(Bolt12SemanticError::InvalidAmount);
 166                 }
 167
 168                 let metadata = Metadata::Bytes(metadata);
 169                 Ok(Self {
 170                         refund: RefundContents {
 171                                 payer: PayerContents(metadata), description, absolute_expiry: None, issuer: None,
 172                                 paths: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
 173                                 quantity: None, payer_id, payer_note: None,
 174                         },
 175                         secp_ctx: None,
 176                 })
 177         }
 178 } }
 179
 180 macro_rules! refund_builder_methods { (
 181         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr, $secp_context: ty $(, $self_mut: tt)?
 182 ) => {
 183         /// Similar to [`RefundBuilder::new`] except, if [`RefundBuilder::path`] is called, the payer id
 184         /// is derived from the given [`ExpandedKey`] and nonce. This provides sender privacy by using a
 185         /// different payer id for each refund, assuming a different nonce is used.  Otherwise, the
 186         /// provided `node_id` is used for the payer id.
 187         ///
 188         /// Also, sets the metadata when [`RefundBuilder::build`] is called such that it can be used to
 189         /// verify that an [`InvoiceRequest`] was produced for the refund given an [`ExpandedKey`].
 190         ///
 191         /// The `payment_id` is encrypted in the metadata and should be unique. This ensures that only
 192         /// one invoice will be paid for the refund and that payments can be uniquely identified.
 193         ///
 194         /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 195         /// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
 196         pub fn deriving_payer_id<ES: Deref>(
 197                 description: String, node_id: PublicKey, expanded_key: &ExpandedKey, entropy_source: ES,
 198                 secp_ctx: &'a Secp256k1<$secp_context>, amount_msats: u64, payment_id: PaymentId
 199         ) -> Result<Self, Bolt12SemanticError> where ES::Target: EntropySource {
 200                 if amount_msats > MAX_VALUE_MSAT {
 201                         return Err(Bolt12SemanticError::InvalidAmount);
 202                 }
 203
 204                 let nonce = Nonce::from_entropy_source(entropy_source);
 205                 let payment_id = Some(payment_id);
 206                 let derivation_material = MetadataMaterial::new(nonce, expanded_key, IV_BYTES, payment_id);
 207                 let metadata = Metadata::DerivedSigningPubkey(derivation_material);
 208                 Ok(Self {
 209                         refund: RefundContents {
 210                                 payer: PayerContents(metadata), description, absolute_expiry: None, issuer: None,
 211                                 paths: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
 212                                 quantity: None, payer_id: node_id, payer_note: None,
 213                         },
 214                         secp_ctx: Some(secp_ctx),
 215                 })
 216         }
 217
 218         /// Sets the [`Refund::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
 219         /// already passed is valid and can be checked for using [`Refund::is_expired`].
 220         ///
 221         /// Successive calls to this method will override the previous setting.
 222         pub fn absolute_expiry($($self_mut)* $self: $self_type, absolute_expiry: Duration) -> $return_type {
 223                 $self.refund.absolute_expiry = Some(absolute_expiry);
 224                 $return_value
 225         }
 226
 227         /// Sets the [`Refund::issuer`].
 228         ///
 229         /// Successive calls to this method will override the previous setting.
 230         pub fn issuer($($self_mut)* $self: $self_type, issuer: String) -> $return_type {
 231                 $self.refund.issuer = Some(issuer);
 232                 $return_value
 233         }
 234
 235         /// Adds a blinded path to [`Refund::paths`]. Must include at least one path if only connected
 236         /// by private channels or if [`Refund::payer_id`] is not a public node id.
 237         ///
 238         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 239         /// adding duplicate paths.
 240         pub fn path($($self_mut)* $self: $self_type, path: BlindedPath) -> $return_type {
 241                 $self.refund.paths.get_or_insert_with(Vec::new).push(path);
 242                 $return_value
 243         }
 244
 245         /// Sets the [`Refund::chain`] of the given [`Network`] for paying an invoice. If not
 246         /// called, [`Network::Bitcoin`] is assumed.
 247         ///
 248         /// Successive calls to this method will override the previous setting.
 249         pub fn chain($self: $self_type, network: Network) -> $return_type {
 250                 $self.chain_hash(ChainHash::using_genesis_block(network))
 251         }
 252
 253         /// Sets the [`Refund::chain`] of the given [`ChainHash`] for paying an invoice. If not called,
 254         /// [`Network::Bitcoin`] is assumed.
 255         ///
 256         /// Successive calls to this method will override the previous setting.
 257         pub(crate) fn chain_hash($($self_mut)* $self: $self_type, chain: ChainHash) -> $return_type {
 258                 $self.refund.chain = Some(chain);
 259                 $return_value
 260         }
 261
 262         /// Sets [`Refund::quantity`] of items. This is purely for informational purposes. It is useful
 263         /// when the refund pertains to a [`Bolt12Invoice`] that paid for more than one item from an
 264         /// [`Offer`] as specified by [`InvoiceRequest::quantity`].
 265         ///
 266         /// Successive calls to this method will override the previous setting.
 267         ///
 268         /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 269         /// [`InvoiceRequest::quantity`]: crate::offers::invoice_request::InvoiceRequest::quantity
 270         /// [`Offer`]: crate::offers::offer::Offer
 271         pub fn quantity($($self_mut)* $self: $self_type, quantity: u64) -> $return_type {
 272                 $self.refund.quantity = Some(quantity);
 273                 $return_value
 274         }
 275
 276         /// Sets the [`Refund::payer_note`].
 277         ///
 278         /// Successive calls to this method will override the previous setting.
 279         pub fn payer_note($($self_mut)* $self: $self_type, payer_note: String) -> $return_type {
 280                 $self.refund.payer_note = Some(payer_note);
 281                 $return_value
 282         }
 283
 284         /// Builds a [`Refund`] after checking for valid semantics.
 285         pub fn build($($self_mut)* $self: $self_type) -> Result<Refund, Bolt12SemanticError> {
 286                 if $self.refund.chain() == $self.refund.implied_chain() {
 287                         $self.refund.chain = None;
 288                 }
 289
 290                 // Create the metadata for stateless verification of a Bolt12Invoice.
 291                 if $self.refund.payer.0.has_derivation_material() {
 292                         let mut metadata = core::mem::take(&mut $self.refund.payer.0);
 293
 294                         if $self.refund.paths.is_none() {
 295                                 metadata = metadata.without_keys();
 296                         }
 297
 298                         let mut tlv_stream = $self.refund.as_tlv_stream();
 299                         tlv_stream.0.metadata = None;
 300                         if metadata.derives_payer_keys() {
 301                                 tlv_stream.2.payer_id = None;
 302                         }
 303
 304                         let (derived_metadata, keys) = metadata.derive_from(tlv_stream, $self.secp_ctx);
 305                         metadata = derived_metadata;
 306                         if let Some(keys) = keys {
 307                                 $self.refund.payer_id = keys.public_key();
 308                         }
 309
 310                         $self.refund.payer.0 = metadata;
 311                 }
 312
 313                 let mut bytes = Vec::new();
 314                 $self.refund.write(&mut bytes).unwrap();
 315
 316                 Ok(Refund {
 317                         bytes,
 318                         #[cfg(not(c_bindings))]
 319                         contents: $self.refund,
 320                         #[cfg(c_bindings)]
 321                         contents: $self.refund.clone(),
 322                 })
 323         }
 324 } }
 325
 326 #[cfg(test)]
 327 macro_rules! refund_builder_test_methods { (
 328         $self: ident, $self_type: ty, $return_type: ty, $return_value: expr $(, $self_mut: tt)?
 329 ) => {
 330         #[cfg_attr(c_bindings, allow(dead_code))]
 331         pub(crate) fn clear_paths($($self_mut)* $self: $self_type) -> $return_type {
 332                 $self.refund.paths = None;
 333                 $return_value
 334         }
 335
 336         #[cfg_attr(c_bindings, allow(dead_code))]
 337         fn features_unchecked($($self_mut)* $self: $self_type, features: InvoiceRequestFeatures) -> $return_type {
 338                 $self.refund.features = features;
 339                 $return_value
 340         }
 341 } }
 342
 343 impl<'a> RefundBuilder<'a, secp256k1::SignOnly> {
 344         refund_explicit_metadata_builder_methods!();
 345 }
 346
 347 impl<'a, T: secp256k1::Signing> RefundBuilder<'a, T> {
 348         refund_builder_methods!(self, Self, Self, self, T, mut);
 349
 350         #[cfg(test)]
 351         refund_builder_test_methods!(self, Self, Self, self, mut);
 352 }
 353
 354 #[cfg(all(c_bindings, not(test)))]
 355 impl<'a> RefundMaybeWithDerivedMetadataBuilder<'a> {
 356         refund_explicit_metadata_builder_methods!();
 357         refund_builder_methods!(self, &mut Self, (), (), secp256k1::All);
 358 }
 359
 360 #[cfg(all(c_bindings, test))]
 361 impl<'a> RefundMaybeWithDerivedMetadataBuilder<'a> {
 362         refund_explicit_metadata_builder_methods!();
 363         refund_builder_methods!(self, &mut Self, &mut Self, self, secp256k1::All);
 364         refund_builder_test_methods!(self, &mut Self, &mut Self, self);
 365 }
 366
 367 #[cfg(c_bindings)]
 368 impl<'a> From<RefundBuilder<'a, secp256k1::All>>
 369 for RefundMaybeWithDerivedMetadataBuilder<'a> {
 370         fn from(builder: RefundBuilder<'a, secp256k1::All>) -> Self {
 371                 let RefundBuilder { refund, secp_ctx } = builder;
 372
 373                 Self { refund, secp_ctx }
 374         }
 375 }
 376
 377 /// A `Refund` is a request to send an [`Bolt12Invoice`] without a preceding [`Offer`].
 378 ///
 379 /// Typically, after an invoice is paid, the recipient may publish a refund allowing the sender to
 380 /// recoup their funds. A refund may be used more generally as an "offer for money", such as with a
 381 /// bitcoin ATM.
 382 ///
 383 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 384 /// [`Offer`]: crate::offers::offer::Offer
 385 #[derive(Clone, Debug)]
 386 #[cfg_attr(test, derive(PartialEq))]
 387 pub struct Refund {
 388         pub(super) bytes: Vec<u8>,
 389         pub(super) contents: RefundContents,
 390 }
 391
 392 /// The contents of a [`Refund`], which may be shared with an [`Bolt12Invoice`].
 393 ///
 394 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 395 #[derive(Clone, Debug)]
 396 #[cfg_attr(test, derive(PartialEq))]
 397 pub(super) struct RefundContents {
 398         payer: PayerContents,
 399         // offer fields
 400         description: String,
 401         absolute_expiry: Option<Duration>,
 402         issuer: Option<String>,
 403         paths: Option<Vec<BlindedPath>>,
 404         // invoice_request fields
 405         chain: Option<ChainHash>,
 406         amount_msats: u64,
 407         features: InvoiceRequestFeatures,
 408         quantity: Option<u64>,
 409         payer_id: PublicKey,
 410         payer_note: Option<String>,
 411 }
 412
 413 impl Refund {
 414         /// A complete description of the purpose of the refund. Intended to be displayed to the user
 415         /// but with the caveat that it has not been verified in any way.
 416         pub fn description(&self) -> PrintableString {
 417                 self.contents.description()
 418         }
 419
 420         /// Duration since the Unix epoch when an invoice should no longer be sent.
 421         ///
 422         /// If `None`, the refund does not expire.
 423         pub fn absolute_expiry(&self) -> Option<Duration> {
 424                 self.contents.absolute_expiry()
 425         }
 426
 427         /// Whether the refund has expired.
 428         #[cfg(feature = "std")]
 429         pub fn is_expired(&self) -> bool {
 430                 self.contents.is_expired()
 431         }
 432
 433         /// Whether the refund has expired given the duration since the Unix epoch.
 434         pub fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 435                 self.contents.is_expired_no_std(duration_since_epoch)
 436         }
 437
 438         /// The issuer of the refund, possibly beginning with `user@domain` or `domain`. Intended to be
 439         /// displayed to the user but with the caveat that it has not been verified in any way.
 440         pub fn issuer(&self) -> Option<PrintableString> {
 441                 self.contents.issuer()
 442         }
 443
 444         /// Paths to the sender originating from publicly reachable nodes. Blinded paths provide sender
 445         /// privacy by obfuscating its node id.
 446         pub fn paths(&self) -> &[BlindedPath] {
 447                 self.contents.paths()
 448         }
 449
 450         /// An unpredictable series of bytes, typically containing information about the derivation of
 451         /// [`payer_id`].
 452         ///
 453         /// [`payer_id`]: Self::payer_id
 454         pub fn payer_metadata(&self) -> &[u8] {
 455                 self.contents.metadata()
 456         }
 457
 458         /// A chain that the refund is valid for.
 459         pub fn chain(&self) -> ChainHash {
 460                 self.contents.chain()
 461         }
 462
 463         /// The amount to refund in msats (i.e., the minimum lightning-payable unit for [`chain`]).
 464         ///
 465         /// [`chain`]: Self::chain
 466         pub fn amount_msats(&self) -> u64 {
 467                 self.contents.amount_msats()
 468         }
 469
 470         /// Features pertaining to requesting an invoice.
 471         pub fn features(&self) -> &InvoiceRequestFeatures {
 472                 &self.contents.features()
 473         }
 474
 475         /// The quantity of an item that refund is for.
 476         pub fn quantity(&self) -> Option<u64> {
 477                 self.contents.quantity()
 478         }
 479
 480         /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
 481         /// transient pubkey.
 482         ///
 483         /// [`paths`]: Self::paths
 484         pub fn payer_id(&self) -> PublicKey {
 485                 self.contents.payer_id()
 486         }
 487
 488         /// Payer provided note to include in the invoice.
 489         pub fn payer_note(&self) -> Option<PrintableString> {
 490                 self.contents.payer_note()
 491         }
 492 }
 493
 494 macro_rules! respond_with_explicit_signing_pubkey_methods { ($self: ident, $builder: ty) => {
 495         /// Creates an [`InvoiceBuilder`] for the refund with the given required fields and using the
 496         /// [`Duration`] since [`std::time::SystemTime::UNIX_EPOCH`] as the creation time.
 497         ///
 498         /// See [`Refund::respond_with_no_std`] for further details where the aforementioned creation
 499         /// time is used for the `created_at` parameter.
 500         ///
 501         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 502         ///
 503         /// [`Duration`]: core::time::Duration
 504         #[cfg(feature = "std")]
 505         pub fn respond_with(
 506                 &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 507                 signing_pubkey: PublicKey,
 508         ) -> Result<$builder, Bolt12SemanticError> {
 509                 let created_at = std::time::SystemTime::now()
 510                         .duration_since(std::time::SystemTime::UNIX_EPOCH)
 511                         .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 512
 513                 $self.respond_with_no_std(payment_paths, payment_hash, signing_pubkey, created_at)
 514         }
 515
 516         /// Creates an [`InvoiceBuilder`] for the refund with the given required fields.
 517         ///
 518         /// Unless [`InvoiceBuilder::relative_expiry`] is set, the invoice will expire two hours after
 519         /// `created_at`, which is used to set [`Bolt12Invoice::created_at`]. Useful for `no-std` builds
 520         /// where [`std::time::SystemTime`] is not available.
 521         ///
 522         /// The caller is expected to remember the preimage of `payment_hash` in order to
 523         /// claim a payment for the invoice.
 524         ///
 525         /// The `signing_pubkey` is required to sign the invoice since refunds are not in response to an
 526         /// offer, which does have a `signing_pubkey`.
 527         ///
 528         /// The `payment_paths` parameter is useful for maintaining the payment recipient's privacy. It
 529         /// must contain one or more elements ordered from most-preferred to least-preferred, if there's
 530         /// a preference. Note, however, that any privacy is lost if a public node id is used for
 531         /// `signing_pubkey`.
 532         ///
 533         /// Errors if the request contains unknown required features.
 534         ///
 535         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 536         ///
 537         /// [`Bolt12Invoice::created_at`]: crate::offers::invoice::Bolt12Invoice::created_at
 538         pub fn respond_with_no_std(
 539                 &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 540                 signing_pubkey: PublicKey, created_at: Duration
 541         ) -> Result<$builder, Bolt12SemanticError> {
 542                 if $self.features().requires_unknown_bits() {
 543                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 544                 }
 545
 546                 <$builder>::for_refund($self, payment_paths, created_at, payment_hash, signing_pubkey)
 547         }
 548 } }
 549
 550 macro_rules! respond_with_derived_signing_pubkey_methods { ($self: ident, $builder: ty) => {
 551         /// Creates an [`InvoiceBuilder`] for the refund using the given required fields and that uses
 552         /// derived signing keys to sign the [`Bolt12Invoice`].
 553         ///
 554         /// See [`Refund::respond_with`] for further details.
 555         ///
 556         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 557         ///
 558         /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 559         #[cfg(feature = "std")]
 560         pub fn respond_using_derived_keys<ES: Deref>(
 561                 &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 562                 expanded_key: &ExpandedKey, entropy_source: ES
 563         ) -> Result<$builder, Bolt12SemanticError>
 564         where
 565                 ES::Target: EntropySource,
 566         {
 567                 let created_at = std::time::SystemTime::now()
 568                         .duration_since(std::time::SystemTime::UNIX_EPOCH)
 569                         .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 570
 571                 $self.respond_using_derived_keys_no_std(
 572                         payment_paths, payment_hash, created_at, expanded_key, entropy_source
 573                 )
 574         }
 575
 576         /// Creates an [`InvoiceBuilder`] for the refund using the given required fields and that uses
 577         /// derived signing keys to sign the [`Bolt12Invoice`].
 578         ///
 579         /// See [`Refund::respond_with_no_std`] for further details.
 580         ///
 581         /// This is not exported to bindings users as builder patterns don't map outside of move semantics.
 582         ///
 583         /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 584         pub fn respond_using_derived_keys_no_std<ES: Deref>(
 585                 &$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 586                 created_at: core::time::Duration, expanded_key: &ExpandedKey, entropy_source: ES
 587         ) -> Result<$builder, Bolt12SemanticError>
 588         where
 589                 ES::Target: EntropySource,
 590         {
 591                 if $self.features().requires_unknown_bits() {
 592                         return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 593                 }
 594
 595                 let nonce = Nonce::from_entropy_source(entropy_source);
 596                 let keys = signer::derive_keys(nonce, expanded_key);
 597                 <$builder>::for_refund_using_keys($self, payment_paths, created_at, payment_hash, keys)
 598         }
 599 } }
 600
 601 #[cfg(not(c_bindings))]
 602 impl Refund {
 603         respond_with_explicit_signing_pubkey_methods!(self, InvoiceBuilder<ExplicitSigningPubkey>);
 604         respond_with_derived_signing_pubkey_methods!(self, InvoiceBuilder<DerivedSigningPubkey>);
 605 }
 606
 607 #[cfg(c_bindings)]
 608 impl Refund {
 609         respond_with_explicit_signing_pubkey_methods!(self, InvoiceWithExplicitSigningPubkeyBuilder);
 610         respond_with_derived_signing_pubkey_methods!(self, InvoiceWithDerivedSigningPubkeyBuilder);
 611 }
 612
 613 #[cfg(test)]
 614 impl Refund {
 615         fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 616                 self.contents.as_tlv_stream()
 617         }
 618 }
 619
 620 impl AsRef<[u8]> for Refund {
 621         fn as_ref(&self) -> &[u8] {
 622                 &self.bytes
 623         }
 624 }
 625
 626 impl RefundContents {
 627         pub fn description(&self) -> PrintableString {
 628                 PrintableString(&self.description)
 629         }
 630
 631         pub fn absolute_expiry(&self) -> Option<Duration> {
 632                 self.absolute_expiry
 633         }
 634
 635         #[cfg(feature = "std")]
 636         pub(super) fn is_expired(&self) -> bool {
 637                 SystemTime::UNIX_EPOCH
 638                         .elapsed()
 639                         .map(|duration_since_epoch| self.is_expired_no_std(duration_since_epoch))
 640                         .unwrap_or(false)
 641         }
 642
 643         pub(super) fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
 644                 self.absolute_expiry
 645                         .map(|absolute_expiry| duration_since_epoch > absolute_expiry)
 646                         .unwrap_or(false)
 647         }
 648
 649         pub fn issuer(&self) -> Option<PrintableString> {
 650                 self.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 651         }
 652
 653         pub fn paths(&self) -> &[BlindedPath] {
 654                 self.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 655         }
 656
 657         pub(super) fn metadata(&self) -> &[u8] {
 658                 self.payer.0.as_bytes().map(|bytes| bytes.as_slice()).unwrap_or(&[])
 659         }
 660
 661         pub(super) fn chain(&self) -> ChainHash {
 662                 self.chain.unwrap_or_else(|| self.implied_chain())
 663         }
 664
 665         pub fn implied_chain(&self) -> ChainHash {
 666                 ChainHash::using_genesis_block(Network::Bitcoin)
 667         }
 668
 669         pub fn amount_msats(&self) -> u64 {
 670                 self.amount_msats
 671         }
 672
 673         /// Features pertaining to requesting an invoice.
 674         pub fn features(&self) -> &InvoiceRequestFeatures {
 675                 &self.features
 676         }
 677
 678         /// The quantity of an item that refund is for.
 679         pub fn quantity(&self) -> Option<u64> {
 680                 self.quantity
 681         }
 682
 683         /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
 684         /// transient pubkey.
 685         ///
 686         /// [`paths`]: Self::paths
 687         pub fn payer_id(&self) -> PublicKey {
 688                 self.payer_id
 689         }
 690
 691         /// Payer provided note to include in the invoice.
 692         pub fn payer_note(&self) -> Option<PrintableString> {
 693                 self.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
 694         }
 695
 696         pub(super) fn derives_keys(&self) -> bool {
 697                 self.payer.0.derives_payer_keys()
 698         }
 699
 700         pub(super) fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 701                 let payer = PayerTlvStreamRef {
 702                         metadata: self.payer.0.as_bytes(),
 703                 };
 704
 705                 let offer = OfferTlvStreamRef {
 706                         chains: None,
 707                         metadata: None,
 708                         currency: None,
 709                         amount: None,
 710                         description: Some(&self.description),
 711                         features: None,
 712                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 713                         paths: self.paths.as_ref(),
 714                         issuer: self.issuer.as_ref(),
 715                         quantity_max: None,
 716                         node_id: None,
 717                 };
 718
 719                 let features = {
 720                         if self.features == InvoiceRequestFeatures::empty() { None }
 721                         else { Some(&self.features) }
 722                 };
 723
 724                 let invoice_request = InvoiceRequestTlvStreamRef {
 725                         chain: self.chain.as_ref(),
 726                         amount: Some(self.amount_msats),
 727                         features,
 728                         quantity: self.quantity,
 729                         payer_id: Some(&self.payer_id),
 730                         payer_note: self.payer_note.as_ref(),
 731                 };
 732
 733                 (payer, offer, invoice_request)
 734         }
 735 }
 736
 737 impl Writeable for Refund {
 738         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 739                 WithoutLength(&self.bytes).write(writer)
 740         }
 741 }
 742
 743 impl Writeable for RefundContents {
 744         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 745                 self.as_tlv_stream().write(writer)
 746         }
 747 }
 748
 749 type RefundTlvStream = (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream);
 750
 751 type RefundTlvStreamRef<'a> = (
 752         PayerTlvStreamRef<'a>,
 753         OfferTlvStreamRef<'a>,
 754         InvoiceRequestTlvStreamRef<'a>,
 755 );
 756
 757 impl SeekReadable for RefundTlvStream {
 758         fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
 759                 let payer = SeekReadable::read(r)?;
 760                 let offer = SeekReadable::read(r)?;
 761                 let invoice_request = SeekReadable::read(r)?;
 762
 763                 Ok((payer, offer, invoice_request))
 764         }
 765 }
 766
 767 impl Bech32Encode for Refund {
 768         const BECH32_HRP: &'static str = "lnr";
 769 }
 770
 771 impl FromStr for Refund {
 772         type Err = Bolt12ParseError;
 773
 774         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 775                 Refund::from_bech32_str(s)
 776         }
 777 }
 778
 779 impl TryFrom<Vec<u8>> for Refund {
 780         type Error = Bolt12ParseError;
 781
 782         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 783                 let refund = ParsedMessage::<RefundTlvStream>::try_from(bytes)?;
 784                 let ParsedMessage { bytes, tlv_stream } = refund;
 785                 let contents = RefundContents::try_from(tlv_stream)?;
 786
 787                 Ok(Refund { bytes, contents })
 788         }
 789 }
 790
 791 impl TryFrom<RefundTlvStream> for RefundContents {
 792         type Error = Bolt12SemanticError;
 793
 794         fn try_from(tlv_stream: RefundTlvStream) -> Result<Self, Self::Error> {
 795                 let (
 796                         PayerTlvStream { metadata: payer_metadata },
 797                         OfferTlvStream {
 798                                 chains, metadata, currency, amount: offer_amount, description,
 799                                 features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
 800                         },
 801                         InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
 802                 ) = tlv_stream;
 803
 804                 let payer = match payer_metadata {
 805                         None => return Err(Bolt12SemanticError::MissingPayerMetadata),
 806                         Some(metadata) => PayerContents(Metadata::Bytes(metadata)),
 807                 };
 808
 809                 if metadata.is_some() {
 810                         return Err(Bolt12SemanticError::UnexpectedMetadata);
 811                 }
 812
 813                 if chains.is_some() {
 814                         return Err(Bolt12SemanticError::UnexpectedChain);
 815                 }
 816
 817                 if currency.is_some() || offer_amount.is_some() {
 818                         return Err(Bolt12SemanticError::UnexpectedAmount);
 819                 }
 820
 821                 let description = match description {
 822                         None => return Err(Bolt12SemanticError::MissingDescription),
 823                         Some(description) => description,
 824                 };
 825
 826                 if offer_features.is_some() {
 827                         return Err(Bolt12SemanticError::UnexpectedFeatures);
 828                 }
 829
 830                 let absolute_expiry = absolute_expiry.map(Duration::from_secs);
 831
 832                 if quantity_max.is_some() {
 833                         return Err(Bolt12SemanticError::UnexpectedQuantity);
 834                 }
 835
 836                 if node_id.is_some() {
 837                         return Err(Bolt12SemanticError::UnexpectedSigningPubkey);
 838                 }
 839
 840                 let amount_msats = match amount {
 841                         None => return Err(Bolt12SemanticError::MissingAmount),
 842                         Some(amount_msats) if amount_msats > MAX_VALUE_MSAT => {
 843                                 return Err(Bolt12SemanticError::InvalidAmount);
 844                         },
 845                         Some(amount_msats) => amount_msats,
 846                 };
 847
 848                 let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
 849
 850                 let payer_id = match payer_id {
 851                         None => return Err(Bolt12SemanticError::MissingPayerId),
 852                         Some(payer_id) => payer_id,
 853                 };
 854
 855                 Ok(RefundContents {
 856                         payer, description, absolute_expiry, issuer, paths, chain, amount_msats, features,
 857                         quantity, payer_id, payer_note,
 858                 })
 859         }
 860 }
 861
 862 impl core::fmt::Display for Refund {
 863         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 864                 self.fmt_bech32_str(f)
 865         }
 866 }
 867
 868 #[cfg(test)]
 869 mod tests {
 870         use super::{Refund, RefundTlvStreamRef};
 871         #[cfg(not(c_bindings))]
 872         use {
 873                 super::RefundBuilder,
 874         };
 875         #[cfg(c_bindings)]
 876         use {
 877                 super::RefundMaybeWithDerivedMetadataBuilder as RefundBuilder,
 878         };
 879
 880         use bitcoin::blockdata::constants::ChainHash;
 881         use bitcoin::network::constants::Network;
 882         use bitcoin::secp256k1::{KeyPair, Secp256k1, SecretKey};
 883         use core::convert::TryFrom;
 884         use core::time::Duration;
 885         use crate::blinded_path::{BlindedHop, BlindedPath};
 886         use crate::sign::KeyMaterial;
 887         use crate::ln::channelmanager::PaymentId;
 888         use crate::ln::features::{InvoiceRequestFeatures, OfferFeatures};
 889         use crate::ln::inbound_payment::ExpandedKey;
 890         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 891         use crate::offers::invoice_request::InvoiceRequestTlvStreamRef;
 892         use crate::offers::offer::OfferTlvStreamRef;
 893         use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
 894         use crate::offers::payer::PayerTlvStreamRef;
 895         use crate::offers::test_utils::*;
 896         use crate::util::ser::{BigSize, Writeable};
 897         use crate::util::string::PrintableString;
 898
 899         trait ToBytes {
 900                 fn to_bytes(&self) -> Vec<u8>;
 901         }
 902
 903         impl<'a> ToBytes for RefundTlvStreamRef<'a> {
 904                 fn to_bytes(&self) -> Vec<u8> {
 905                         let mut buffer = Vec::new();
 906                         self.write(&mut buffer).unwrap();
 907                         buffer
 908                 }
 909         }
 910
 911         #[test]
 912         fn builds_refund_with_defaults() {
 913                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 914                         .build().unwrap();
 915
 916                 let mut buffer = Vec::new();
 917                 refund.write(&mut buffer).unwrap();
 918
 919                 assert_eq!(refund.bytes, buffer.as_slice());
 920                 assert_eq!(refund.payer_metadata(), &[1; 32]);
 921                 assert_eq!(refund.description(), PrintableString("foo"));
 922                 assert_eq!(refund.absolute_expiry(), None);
 923                 #[cfg(feature = "std")]
 924                 assert!(!refund.is_expired());
 925                 assert_eq!(refund.paths(), &[]);
 926                 assert_eq!(refund.issuer(), None);
 927                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Bitcoin));
 928                 assert_eq!(refund.amount_msats(), 1000);
 929                 assert_eq!(refund.features(), &InvoiceRequestFeatures::empty());
 930                 assert_eq!(refund.payer_id(), payer_pubkey());
 931                 assert_eq!(refund.payer_note(), None);
 932
 933                 assert_eq!(
 934                         refund.as_tlv_stream(),
 935                         (
 936                                 PayerTlvStreamRef { metadata: Some(&vec![1; 32]) },
 937                                 OfferTlvStreamRef {
 938                                         chains: None,
 939                                         metadata: None,
 940                                         currency: None,
 941                                         amount: None,
 942                                         description: Some(&String::from("foo")),
 943                                         features: None,
 944                                         absolute_expiry: None,
 945                                         paths: None,
 946                                         issuer: None,
 947                                         quantity_max: None,
 948                                         node_id: None,
 949                                 },
 950                                 InvoiceRequestTlvStreamRef {
 951                                         chain: None,
 952                                         amount: Some(1000),
 953                                         features: None,
 954                                         quantity: None,
 955                                         payer_id: Some(&payer_pubkey()),
 956                                         payer_note: None,
 957                                 },
 958                         ),
 959                 );
 960
 961                 if let Err(e) = Refund::try_from(buffer) {
 962                         panic!("error parsing refund: {:?}", e);
 963                 }
 964         }
 965
 966         #[test]
 967         fn fails_building_refund_with_invalid_amount() {
 968                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), MAX_VALUE_MSAT + 1) {
 969                         Ok(_) => panic!("expected error"),
 970                         Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
 971                 }
 972         }
 973
 974         #[test]
 975         fn builds_refund_with_metadata_derived() {
 976                 let desc = "foo".to_string();
 977                 let node_id = payer_pubkey();
 978                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
 979                 let entropy = FixedEntropy {};
 980                 let secp_ctx = Secp256k1::new();
 981                 let payment_id = PaymentId([1; 32]);
 982
 983                 let refund = RefundBuilder
 984                         ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
 985                         .unwrap()
 986                         .build().unwrap();
 987                 assert_eq!(refund.payer_id(), node_id);
 988
 989                 // Fails verification with altered fields
 990                 let invoice = refund
 991                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
 992                         .unwrap()
 993                         .build().unwrap()
 994                         .sign(recipient_sign).unwrap();
 995                 match invoice.verify(&expanded_key, &secp_ctx) {
 996                         Ok(payment_id) => assert_eq!(payment_id, PaymentId([1; 32])),
 997                         Err(()) => panic!("verification failed"),
 998                 }
 999
1000                 let mut tlv_stream = refund.as_tlv_stream();
1001                 tlv_stream.2.amount = Some(2000);
1002
1003                 let mut encoded_refund = Vec::new();
1004                 tlv_stream.write(&mut encoded_refund).unwrap();
1005
1006                 let invoice = Refund::try_from(encoded_refund).unwrap()
1007                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1008                         .unwrap()
1009                         .build().unwrap()
1010                         .sign(recipient_sign).unwrap();
1011                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
1012
1013                 // Fails verification with altered metadata
1014                 let mut tlv_stream = refund.as_tlv_stream();
1015                 let metadata = tlv_stream.0.metadata.unwrap().iter().copied().rev().collect();
1016                 tlv_stream.0.metadata = Some(&metadata);
1017
1018                 let mut encoded_refund = Vec::new();
1019                 tlv_stream.write(&mut encoded_refund).unwrap();
1020
1021                 let invoice = Refund::try_from(encoded_refund).unwrap()
1022                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1023                         .unwrap()
1024                         .build().unwrap()
1025                         .sign(recipient_sign).unwrap();
1026                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
1027         }
1028
1029         #[test]
1030         fn builds_refund_with_derived_payer_id() {
1031                 let desc = "foo".to_string();
1032                 let node_id = payer_pubkey();
1033                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
1034                 let entropy = FixedEntropy {};
1035                 let secp_ctx = Secp256k1::new();
1036                 let payment_id = PaymentId([1; 32]);
1037
1038                 let blinded_path = BlindedPath {
1039                         introduction_node_id: pubkey(40),
1040                         blinding_point: pubkey(41),
1041                         blinded_hops: vec![
1042                                 BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1043                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
1044                         ],
1045                 };
1046
1047                 let refund = RefundBuilder
1048                         ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
1049                         .unwrap()
1050                         .path(blinded_path)
1051                         .build().unwrap();
1052                 assert_ne!(refund.payer_id(), node_id);
1053
1054                 let invoice = refund
1055                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1056                         .unwrap()
1057                         .build().unwrap()
1058                         .sign(recipient_sign).unwrap();
1059                 match invoice.verify(&expanded_key, &secp_ctx) {
1060                         Ok(payment_id) => assert_eq!(payment_id, PaymentId([1; 32])),
1061                         Err(()) => panic!("verification failed"),
1062                 }
1063
1064                 // Fails verification with altered fields
1065                 let mut tlv_stream = refund.as_tlv_stream();
1066                 tlv_stream.2.amount = Some(2000);
1067
1068                 let mut encoded_refund = Vec::new();
1069                 tlv_stream.write(&mut encoded_refund).unwrap();
1070
1071                 let invoice = Refund::try_from(encoded_refund).unwrap()
1072                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1073                         .unwrap()
1074                         .build().unwrap()
1075                         .sign(recipient_sign).unwrap();
1076                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
1077
1078                 // Fails verification with altered payer_id
1079                 let mut tlv_stream = refund.as_tlv_stream();
1080                 let payer_id = pubkey(1);
1081                 tlv_stream.2.payer_id = Some(&payer_id);
1082
1083                 let mut encoded_refund = Vec::new();
1084                 tlv_stream.write(&mut encoded_refund).unwrap();
1085
1086                 let invoice = Refund::try_from(encoded_refund).unwrap()
1087                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1088                         .unwrap()
1089                         .build().unwrap()
1090                         .sign(recipient_sign).unwrap();
1091                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
1092         }
1093
1094         #[test]
1095         fn builds_refund_with_absolute_expiry() {
1096                 let future_expiry = Duration::from_secs(u64::max_value());
1097                 let past_expiry = Duration::from_secs(0);
1098                 let now = future_expiry - Duration::from_secs(1_000);
1099
1100                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1101                         .absolute_expiry(future_expiry)
1102                         .build()
1103                         .unwrap();
1104                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1105                 #[cfg(feature = "std")]
1106                 assert!(!refund.is_expired());
1107                 assert!(!refund.is_expired_no_std(now));
1108                 assert_eq!(refund.absolute_expiry(), Some(future_expiry));
1109                 assert_eq!(tlv_stream.absolute_expiry, Some(future_expiry.as_secs()));
1110
1111                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1112                         .absolute_expiry(future_expiry)
1113                         .absolute_expiry(past_expiry)
1114                         .build()
1115                         .unwrap();
1116                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1117                 #[cfg(feature = "std")]
1118                 assert!(refund.is_expired());
1119                 assert!(refund.is_expired_no_std(now));
1120                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
1121                 assert_eq!(tlv_stream.absolute_expiry, Some(past_expiry.as_secs()));
1122         }
1123
1124         #[test]
1125         fn builds_refund_with_paths() {
1126                 let paths = vec![
1127                         BlindedPath {
1128                                 introduction_node_id: pubkey(40),
1129                                 blinding_point: pubkey(41),
1130                                 blinded_hops: vec![
1131                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1132                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1133                                 ],
1134                         },
1135                         BlindedPath {
1136                                 introduction_node_id: pubkey(40),
1137                                 blinding_point: pubkey(41),
1138                                 blinded_hops: vec![
1139                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1140                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1141                                 ],
1142                         },
1143                 ];
1144
1145                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1146                         .path(paths[0].clone())
1147                         .path(paths[1].clone())
1148                         .build()
1149                         .unwrap();
1150                 let (_, offer_tlv_stream, invoice_request_tlv_stream) = refund.as_tlv_stream();
1151                 assert_eq!(refund.paths(), paths.as_slice());
1152                 assert_eq!(refund.payer_id(), pubkey(42));
1153                 assert_ne!(pubkey(42), pubkey(44));
1154                 assert_eq!(offer_tlv_stream.paths, Some(&paths));
1155                 assert_eq!(invoice_request_tlv_stream.payer_id, Some(&pubkey(42)));
1156         }
1157
1158         #[test]
1159         fn builds_refund_with_issuer() {
1160                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1161                         .issuer("bar".into())
1162                         .build()
1163                         .unwrap();
1164                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1165                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
1166                 assert_eq!(tlv_stream.issuer, Some(&String::from("bar")));
1167
1168                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1169                         .issuer("bar".into())
1170                         .issuer("baz".into())
1171                         .build()
1172                         .unwrap();
1173                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1174                 assert_eq!(refund.issuer(), Some(PrintableString("baz")));
1175                 assert_eq!(tlv_stream.issuer, Some(&String::from("baz")));
1176         }
1177
1178         #[test]
1179         fn builds_refund_with_chain() {
1180                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
1181                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
1182
1183                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1184                         .chain(Network::Bitcoin)
1185                         .build().unwrap();
1186                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1187                 assert_eq!(refund.chain(), mainnet);
1188                 assert_eq!(tlv_stream.chain, None);
1189
1190                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1191                         .chain(Network::Testnet)
1192                         .build().unwrap();
1193                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1194                 assert_eq!(refund.chain(), testnet);
1195                 assert_eq!(tlv_stream.chain, Some(&testnet));
1196
1197                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1198                         .chain(Network::Regtest)
1199                         .chain(Network::Testnet)
1200                         .build().unwrap();
1201                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1202                 assert_eq!(refund.chain(), testnet);
1203                 assert_eq!(tlv_stream.chain, Some(&testnet));
1204         }
1205
1206         #[test]
1207         fn builds_refund_with_quantity() {
1208                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1209                         .quantity(10)
1210                         .build().unwrap();
1211                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1212                 assert_eq!(refund.quantity(), Some(10));
1213                 assert_eq!(tlv_stream.quantity, Some(10));
1214
1215                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1216                         .quantity(10)
1217                         .quantity(1)
1218                         .build().unwrap();
1219                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1220                 assert_eq!(refund.quantity(), Some(1));
1221                 assert_eq!(tlv_stream.quantity, Some(1));
1222         }
1223
1224         #[test]
1225         fn builds_refund_with_payer_note() {
1226                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1227                         .payer_note("bar".into())
1228                         .build().unwrap();
1229                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1230                 assert_eq!(refund.payer_note(), Some(PrintableString("bar")));
1231                 assert_eq!(tlv_stream.payer_note, Some(&String::from("bar")));
1232
1233                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1234                         .payer_note("bar".into())
1235                         .payer_note("baz".into())
1236                         .build().unwrap();
1237                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1238                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
1239                 assert_eq!(tlv_stream.payer_note, Some(&String::from("baz")));
1240         }
1241
1242         #[test]
1243         fn fails_responding_with_unknown_required_features() {
1244                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1245                         .features_unchecked(InvoiceRequestFeatures::unknown())
1246                         .build().unwrap()
1247                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1248                 {
1249                         Ok(_) => panic!("expected error"),
1250                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnknownRequiredFeatures),
1251                 }
1252         }
1253
1254         #[test]
1255         fn parses_refund_with_metadata() {
1256                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1257                         .build().unwrap();
1258                 if let Err(e) = refund.to_string().parse::<Refund>() {
1259                         panic!("error parsing refund: {:?}", e);
1260                 }
1261
1262                 let mut tlv_stream = refund.as_tlv_stream();
1263                 tlv_stream.0.metadata = None;
1264
1265                 match Refund::try_from(tlv_stream.to_bytes()) {
1266                         Ok(_) => panic!("expected error"),
1267                         Err(e) => {
1268                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingPayerMetadata));
1269                         },
1270                 }
1271         }
1272
1273         #[test]
1274         fn parses_refund_with_description() {
1275                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1276                         .build().unwrap();
1277                 if let Err(e) = refund.to_string().parse::<Refund>() {
1278                         panic!("error parsing refund: {:?}", e);
1279                 }
1280
1281                 let mut tlv_stream = refund.as_tlv_stream();
1282                 tlv_stream.1.description = None;
1283
1284                 match Refund::try_from(tlv_stream.to_bytes()) {
1285                         Ok(_) => panic!("expected error"),
1286                         Err(e) => {
1287                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription));
1288                         },
1289                 }
1290         }
1291
1292         #[test]
1293         fn parses_refund_with_amount() {
1294                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1295                         .build().unwrap();
1296                 if let Err(e) = refund.to_string().parse::<Refund>() {
1297                         panic!("error parsing refund: {:?}", e);
1298                 }
1299
1300                 let mut tlv_stream = refund.as_tlv_stream();
1301                 tlv_stream.2.amount = None;
1302
1303                 match Refund::try_from(tlv_stream.to_bytes()) {
1304                         Ok(_) => panic!("expected error"),
1305                         Err(e) => {
1306                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingAmount));
1307                         },
1308                 }
1309
1310                 let mut tlv_stream = refund.as_tlv_stream();
1311                 tlv_stream.2.amount = Some(MAX_VALUE_MSAT + 1);
1312
1313                 match Refund::try_from(tlv_stream.to_bytes()) {
1314                         Ok(_) => panic!("expected error"),
1315                         Err(e) => {
1316                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InvalidAmount));
1317                         },
1318                 }
1319         }
1320
1321         #[test]
1322         fn parses_refund_with_payer_id() {
1323                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1324                         .build().unwrap();
1325                 if let Err(e) = refund.to_string().parse::<Refund>() {
1326                         panic!("error parsing refund: {:?}", e);
1327                 }
1328
1329                 let mut tlv_stream = refund.as_tlv_stream();
1330                 tlv_stream.2.payer_id = None;
1331
1332                 match Refund::try_from(tlv_stream.to_bytes()) {
1333                         Ok(_) => panic!("expected error"),
1334                         Err(e) => {
1335                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingPayerId));
1336                         },
1337                 }
1338         }
1339
1340         #[test]
1341         fn parses_refund_with_optional_fields() {
1342                 let past_expiry = Duration::from_secs(0);
1343                 let paths = vec![
1344                         BlindedPath {
1345                                 introduction_node_id: pubkey(40),
1346                                 blinding_point: pubkey(41),
1347                                 blinded_hops: vec![
1348                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1349                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1350                                 ],
1351                         },
1352                         BlindedPath {
1353                                 introduction_node_id: pubkey(40),
1354                                 blinding_point: pubkey(41),
1355                                 blinded_hops: vec![
1356                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1357                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1358                                 ],
1359                         },
1360                 ];
1361
1362                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1363                         .absolute_expiry(past_expiry)
1364                         .issuer("bar".into())
1365                         .path(paths[0].clone())
1366                         .path(paths[1].clone())
1367                         .chain(Network::Testnet)
1368                         .features_unchecked(InvoiceRequestFeatures::unknown())
1369                         .quantity(10)
1370                         .payer_note("baz".into())
1371                         .build()
1372                         .unwrap();
1373                 match refund.to_string().parse::<Refund>() {
1374                         Ok(refund) => {
1375                                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
1376                                 #[cfg(feature = "std")]
1377                                 assert!(refund.is_expired());
1378                                 assert_eq!(refund.paths(), &paths[..]);
1379                                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
1380                                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Testnet));
1381                                 assert_eq!(refund.features(), &InvoiceRequestFeatures::unknown());
1382                                 assert_eq!(refund.quantity(), Some(10));
1383                                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
1384                         },
1385                         Err(e) => panic!("error parsing refund: {:?}", e),
1386                 }
1387         }
1388
1389         #[test]
1390         fn fails_parsing_refund_with_unexpected_fields() {
1391                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1392                         .build().unwrap();
1393                 if let Err(e) = refund.to_string().parse::<Refund>() {
1394                         panic!("error parsing refund: {:?}", e);
1395                 }
1396
1397                 let metadata = vec![42; 32];
1398                 let mut tlv_stream = refund.as_tlv_stream();
1399                 tlv_stream.1.metadata = Some(&metadata);
1400
1401                 match Refund::try_from(tlv_stream.to_bytes()) {
1402                         Ok(_) => panic!("expected error"),
1403                         Err(e) => {
1404                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedMetadata));
1405                         },
1406                 }
1407
1408                 let chains = vec![ChainHash::using_genesis_block(Network::Testnet)];
1409                 let mut tlv_stream = refund.as_tlv_stream();
1410                 tlv_stream.1.chains = Some(&chains);
1411
1412                 match Refund::try_from(tlv_stream.to_bytes()) {
1413                         Ok(_) => panic!("expected error"),
1414                         Err(e) => {
1415                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedChain));
1416                         },
1417                 }
1418
1419                 let mut tlv_stream = refund.as_tlv_stream();
1420                 tlv_stream.1.currency = Some(&b"USD");
1421                 tlv_stream.1.amount = Some(1000);
1422
1423                 match Refund::try_from(tlv_stream.to_bytes()) {
1424                         Ok(_) => panic!("expected error"),
1425                         Err(e) => {
1426                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedAmount));
1427                         },
1428                 }
1429
1430                 let features = OfferFeatures::unknown();
1431                 let mut tlv_stream = refund.as_tlv_stream();
1432                 tlv_stream.1.features = Some(&features);
1433
1434                 match Refund::try_from(tlv_stream.to_bytes()) {
1435                         Ok(_) => panic!("expected error"),
1436                         Err(e) => {
1437                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedFeatures));
1438                         },
1439                 }
1440
1441                 let mut tlv_stream = refund.as_tlv_stream();
1442                 tlv_stream.1.quantity_max = Some(10);
1443
1444                 match Refund::try_from(tlv_stream.to_bytes()) {
1445                         Ok(_) => panic!("expected error"),
1446                         Err(e) => {
1447                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedQuantity));
1448                         },
1449                 }
1450
1451                 let node_id = payer_pubkey();
1452                 let mut tlv_stream = refund.as_tlv_stream();
1453                 tlv_stream.1.node_id = Some(&node_id);
1454
1455                 match Refund::try_from(tlv_stream.to_bytes()) {
1456                         Ok(_) => panic!("expected error"),
1457                         Err(e) => {
1458                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedSigningPubkey));
1459                         },
1460                 }
1461         }
1462
1463         #[test]
1464         fn fails_parsing_refund_with_extra_tlv_records() {
1465                 let secp_ctx = Secp256k1::new();
1466                 let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
1467                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], keys.public_key(), 1000).unwrap()
1468                         .build().unwrap();
1469
1470                 let mut encoded_refund = Vec::new();
1471                 refund.write(&mut encoded_refund).unwrap();
1472                 BigSize(1002).write(&mut encoded_refund).unwrap();
1473                 BigSize(32).write(&mut encoded_refund).unwrap();
1474                 [42u8; 32].write(&mut encoded_refund).unwrap();
1475
1476                 match Refund::try_from(encoded_refund) {
1477                         Ok(_) => panic!("expected error"),
1478                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1479                 }
1480         }
1481 }