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