_ 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                 match self.absolute_expiry {
 544                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
 545                                 Ok(elapsed) => elapsed > seconds_from_epoch,
 546                                 Err(_) => false,
 547                         },
 548                         None => false,
 549                 }
 550         }
 551
 552         pub fn issuer(&self) -> Option<PrintableString> {
 553                 self.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 554         }
 555
 556         pub fn paths(&self) -> &[BlindedPath] {
 557                 self.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 558         }
 559
 560         pub(super) fn metadata(&self) -> &[u8] {
 561                 self.payer.0.as_bytes().map(|bytes| bytes.as_slice()).unwrap_or(&[])
 562         }
 563
 564         pub(super) fn chain(&self) -> ChainHash {
 565                 self.chain.unwrap_or_else(|| self.implied_chain())
 566         }
 567
 568         pub fn implied_chain(&self) -> ChainHash {
 569                 ChainHash::using_genesis_block(Network::Bitcoin)
 570         }
 571
 572         pub fn amount_msats(&self) -> u64 {
 573                 self.amount_msats
 574         }
 575
 576         /// Features pertaining to requesting an invoice.
 577         pub fn features(&self) -> &InvoiceRequestFeatures {
 578                 &self.features
 579         }
 580
 581         /// The quantity of an item that refund is for.
 582         pub fn quantity(&self) -> Option<u64> {
 583                 self.quantity
 584         }
 585
 586         /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
 587         /// transient pubkey.
 588         ///
 589         /// [`paths`]: Self::paths
 590         pub fn payer_id(&self) -> PublicKey {
 591                 self.payer_id
 592         }
 593
 594         /// Payer provided note to include in the invoice.
 595         pub fn payer_note(&self) -> Option<PrintableString> {
 596                 self.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
 597         }
 598
 599         pub(super) fn derives_keys(&self) -> bool {
 600                 self.payer.0.derives_payer_keys()
 601         }
 602
 603         pub(super) fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 604                 let payer = PayerTlvStreamRef {
 605                         metadata: self.payer.0.as_bytes(),
 606                 };
 607
 608                 let offer = OfferTlvStreamRef {
 609                         chains: None,
 610                         metadata: None,
 611                         currency: None,
 612                         amount: None,
 613                         description: Some(&self.description),
 614                         features: None,
 615                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 616                         paths: self.paths.as_ref(),
 617                         issuer: self.issuer.as_ref(),
 618                         quantity_max: None,
 619                         node_id: None,
 620                 };
 621
 622                 let features = {
 623                         if self.features == InvoiceRequestFeatures::empty() { None }
 624                         else { Some(&self.features) }
 625                 };
 626
 627                 let invoice_request = InvoiceRequestTlvStreamRef {
 628                         chain: self.chain.as_ref(),
 629                         amount: Some(self.amount_msats),
 630                         features,
 631                         quantity: self.quantity,
 632                         payer_id: Some(&self.payer_id),
 633                         payer_note: self.payer_note.as_ref(),
 634                 };
 635
 636                 (payer, offer, invoice_request)
 637         }
 638 }
 639
 640 impl Writeable for Refund {
 641         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 642                 WithoutLength(&self.bytes).write(writer)
 643         }
 644 }
 645
 646 impl Writeable for RefundContents {
 647         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 648                 self.as_tlv_stream().write(writer)
 649         }
 650 }
 651
 652 type RefundTlvStream = (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream);
 653
 654 type RefundTlvStreamRef<'a> = (
 655         PayerTlvStreamRef<'a>,
 656         OfferTlvStreamRef<'a>,
 657         InvoiceRequestTlvStreamRef<'a>,
 658 );
 659
 660 impl SeekReadable for RefundTlvStream {
 661         fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
 662                 let payer = SeekReadable::read(r)?;
 663                 let offer = SeekReadable::read(r)?;
 664                 let invoice_request = SeekReadable::read(r)?;
 665
 666                 Ok((payer, offer, invoice_request))
 667         }
 668 }
 669
 670 impl Bech32Encode for Refund {
 671         const BECH32_HRP: &'static str = "lnr";
 672 }
 673
 674 impl FromStr for Refund {
 675         type Err = Bolt12ParseError;
 676
 677         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 678                 Refund::from_bech32_str(s)
 679         }
 680 }
 681
 682 impl TryFrom<Vec<u8>> for Refund {
 683         type Error = Bolt12ParseError;
 684
 685         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 686                 let refund = ParsedMessage::<RefundTlvStream>::try_from(bytes)?;
 687                 let ParsedMessage { bytes, tlv_stream } = refund;
 688                 let contents = RefundContents::try_from(tlv_stream)?;
 689
 690                 Ok(Refund { bytes, contents })
 691         }
 692 }
 693
 694 impl TryFrom<RefundTlvStream> for RefundContents {
 695         type Error = Bolt12SemanticError;
 696
 697         fn try_from(tlv_stream: RefundTlvStream) -> Result<Self, Self::Error> {
 698                 let (
 699                         PayerTlvStream { metadata: payer_metadata },
 700                         OfferTlvStream {
 701                                 chains, metadata, currency, amount: offer_amount, description,
 702                                 features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
 703                         },
 704                         InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
 705                 ) = tlv_stream;
 706
 707                 let payer = match payer_metadata {
 708                         None => return Err(Bolt12SemanticError::MissingPayerMetadata),
 709                         Some(metadata) => PayerContents(Metadata::Bytes(metadata)),
 710                 };
 711
 712                 if metadata.is_some() {
 713                         return Err(Bolt12SemanticError::UnexpectedMetadata);
 714                 }
 715
 716                 if chains.is_some() {
 717                         return Err(Bolt12SemanticError::UnexpectedChain);
 718                 }
 719
 720                 if currency.is_some() || offer_amount.is_some() {
 721                         return Err(Bolt12SemanticError::UnexpectedAmount);
 722                 }
 723
 724                 let description = match description {
 725                         None => return Err(Bolt12SemanticError::MissingDescription),
 726                         Some(description) => description,
 727                 };
 728
 729                 if offer_features.is_some() {
 730                         return Err(Bolt12SemanticError::UnexpectedFeatures);
 731                 }
 732
 733                 let absolute_expiry = absolute_expiry.map(Duration::from_secs);
 734
 735                 if quantity_max.is_some() {
 736                         return Err(Bolt12SemanticError::UnexpectedQuantity);
 737                 }
 738
 739                 if node_id.is_some() {
 740                         return Err(Bolt12SemanticError::UnexpectedSigningPubkey);
 741                 }
 742
 743                 let amount_msats = match amount {
 744                         None => return Err(Bolt12SemanticError::MissingAmount),
 745                         Some(amount_msats) if amount_msats > MAX_VALUE_MSAT => {
 746                                 return Err(Bolt12SemanticError::InvalidAmount);
 747                         },
 748                         Some(amount_msats) => amount_msats,
 749                 };
 750
 751                 let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
 752
 753                 let payer_id = match payer_id {
 754                         None => return Err(Bolt12SemanticError::MissingPayerId),
 755                         Some(payer_id) => payer_id,
 756                 };
 757
 758                 Ok(RefundContents {
 759                         payer, description, absolute_expiry, issuer, paths, chain, amount_msats, features,
 760                         quantity, payer_id, payer_note,
 761                 })
 762         }
 763 }
 764
 765 impl core::fmt::Display for Refund {
 766         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 767                 self.fmt_bech32_str(f)
 768         }
 769 }
 770
 771 #[cfg(test)]
 772 mod tests {
 773         use super::{Refund, RefundBuilder, RefundTlvStreamRef};
 774
 775         use bitcoin::blockdata::constants::ChainHash;
 776         use bitcoin::network::constants::Network;
 777         use bitcoin::secp256k1::{KeyPair, Secp256k1, SecretKey};
 778         use core::convert::TryFrom;
 779         use core::time::Duration;
 780         use crate::blinded_path::{BlindedHop, BlindedPath};
 781         use crate::sign::KeyMaterial;
 782         use crate::ln::channelmanager::PaymentId;
 783         use crate::ln::features::{InvoiceRequestFeatures, OfferFeatures};
 784         use crate::ln::inbound_payment::ExpandedKey;
 785         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 786         use crate::offers::invoice_request::InvoiceRequestTlvStreamRef;
 787         use crate::offers::offer::OfferTlvStreamRef;
 788         use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
 789         use crate::offers::payer::PayerTlvStreamRef;
 790         use crate::offers::test_utils::*;
 791         use crate::util::ser::{BigSize, Writeable};
 792         use crate::util::string::PrintableString;
 793
 794         trait ToBytes {
 795                 fn to_bytes(&self) -> Vec<u8>;
 796         }
 797
 798         impl<'a> ToBytes for RefundTlvStreamRef<'a> {
 799                 fn to_bytes(&self) -> Vec<u8> {
 800                         let mut buffer = Vec::new();
 801                         self.write(&mut buffer).unwrap();
 802                         buffer
 803                 }
 804         }
 805
 806         #[test]
 807         fn builds_refund_with_defaults() {
 808                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 809                         .build().unwrap();
 810
 811                 let mut buffer = Vec::new();
 812                 refund.write(&mut buffer).unwrap();
 813
 814                 assert_eq!(refund.bytes, buffer.as_slice());
 815                 assert_eq!(refund.payer_metadata(), &[1; 32]);
 816                 assert_eq!(refund.description(), PrintableString("foo"));
 817                 assert_eq!(refund.absolute_expiry(), None);
 818                 #[cfg(feature = "std")]
 819                 assert!(!refund.is_expired());
 820                 assert_eq!(refund.paths(), &[]);
 821                 assert_eq!(refund.issuer(), None);
 822                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Bitcoin));
 823                 assert_eq!(refund.amount_msats(), 1000);
 824                 assert_eq!(refund.features(), &InvoiceRequestFeatures::empty());
 825                 assert_eq!(refund.payer_id(), payer_pubkey());
 826                 assert_eq!(refund.payer_note(), None);
 827
 828                 assert_eq!(
 829                         refund.as_tlv_stream(),
 830                         (
 831                                 PayerTlvStreamRef { metadata: Some(&vec![1; 32]) },
 832                                 OfferTlvStreamRef {
 833                                         chains: None,
 834                                         metadata: None,
 835                                         currency: None,
 836                                         amount: None,
 837                                         description: Some(&String::from("foo")),
 838                                         features: None,
 839                                         absolute_expiry: None,
 840                                         paths: None,
 841                                         issuer: None,
 842                                         quantity_max: None,
 843                                         node_id: None,
 844                                 },
 845                                 InvoiceRequestTlvStreamRef {
 846                                         chain: None,
 847                                         amount: Some(1000),
 848                                         features: None,
 849                                         quantity: None,
 850                                         payer_id: Some(&payer_pubkey()),
 851                                         payer_note: None,
 852                                 },
 853                         ),
 854                 );
 855
 856                 if let Err(e) = Refund::try_from(buffer) {
 857                         panic!("error parsing refund: {:?}", e);
 858                 }
 859         }
 860
 861         #[test]
 862         fn fails_building_refund_with_invalid_amount() {
 863                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), MAX_VALUE_MSAT + 1) {
 864                         Ok(_) => panic!("expected error"),
 865                         Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
 866                 }
 867         }
 868
 869         #[test]
 870         fn builds_refund_with_metadata_derived() {
 871                 let desc = "foo".to_string();
 872                 let node_id = payer_pubkey();
 873                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
 874                 let entropy = FixedEntropy {};
 875                 let secp_ctx = Secp256k1::new();
 876                 let payment_id = PaymentId([1; 32]);
 877
 878                 let refund = RefundBuilder
 879                         ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
 880                         .unwrap()
 881                         .build().unwrap();
 882                 assert_eq!(refund.payer_id(), node_id);
 883
 884                 // Fails verification with altered fields
 885                 let invoice = refund
 886                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
 887                         .unwrap()
 888                         .build().unwrap()
 889                         .sign(recipient_sign).unwrap();
 890                 match invoice.verify(&expanded_key, &secp_ctx) {
 891                         Ok(payment_id) => assert_eq!(payment_id, PaymentId([1; 32])),
 892                         Err(()) => panic!("verification failed"),
 893                 }
 894
 895                 let mut tlv_stream = refund.as_tlv_stream();
 896                 tlv_stream.2.amount = Some(2000);
 897
 898                 let mut encoded_refund = Vec::new();
 899                 tlv_stream.write(&mut encoded_refund).unwrap();
 900
 901                 let invoice = Refund::try_from(encoded_refund).unwrap()
 902                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
 903                         .unwrap()
 904                         .build().unwrap()
 905                         .sign(recipient_sign).unwrap();
 906                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
 907
 908                 // Fails verification with altered metadata
 909                 let mut tlv_stream = refund.as_tlv_stream();
 910                 let metadata = tlv_stream.0.metadata.unwrap().iter().copied().rev().collect();
 911                 tlv_stream.0.metadata = Some(&metadata);
 912
 913                 let mut encoded_refund = Vec::new();
 914                 tlv_stream.write(&mut encoded_refund).unwrap();
 915
 916                 let invoice = Refund::try_from(encoded_refund).unwrap()
 917                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
 918                         .unwrap()
 919                         .build().unwrap()
 920                         .sign(recipient_sign).unwrap();
 921                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
 922         }
 923
 924         #[test]
 925         fn builds_refund_with_derived_payer_id() {
 926                 let desc = "foo".to_string();
 927                 let node_id = payer_pubkey();
 928                 let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
 929                 let entropy = FixedEntropy {};
 930                 let secp_ctx = Secp256k1::new();
 931                 let payment_id = PaymentId([1; 32]);
 932
 933                 let blinded_path = BlindedPath {
 934                         introduction_node_id: pubkey(40),
 935                         blinding_point: pubkey(41),
 936                         blinded_hops: vec![
 937                                 BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
 938                                 BlindedHop { blinded_node_id: node_id, encrypted_payload: vec![0; 44] },
 939                         ],
 940                 };
 941
 942                 let refund = RefundBuilder
 943                         ::deriving_payer_id(desc, node_id, &expanded_key, &entropy, &secp_ctx, 1000, payment_id)
 944                         .unwrap()
 945                         .path(blinded_path)
 946                         .build().unwrap();
 947                 assert_ne!(refund.payer_id(), node_id);
 948
 949                 let invoice = refund
 950                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
 951                         .unwrap()
 952                         .build().unwrap()
 953                         .sign(recipient_sign).unwrap();
 954                 match invoice.verify(&expanded_key, &secp_ctx) {
 955                         Ok(payment_id) => assert_eq!(payment_id, PaymentId([1; 32])),
 956                         Err(()) => panic!("verification failed"),
 957                 }
 958
 959                 // Fails verification with altered fields
 960                 let mut tlv_stream = refund.as_tlv_stream();
 961                 tlv_stream.2.amount = Some(2000);
 962
 963                 let mut encoded_refund = Vec::new();
 964                 tlv_stream.write(&mut encoded_refund).unwrap();
 965
 966                 let invoice = Refund::try_from(encoded_refund).unwrap()
 967                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
 968                         .unwrap()
 969                         .build().unwrap()
 970                         .sign(recipient_sign).unwrap();
 971                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
 972
 973                 // Fails verification with altered payer_id
 974                 let mut tlv_stream = refund.as_tlv_stream();
 975                 let payer_id = pubkey(1);
 976                 tlv_stream.2.payer_id = Some(&payer_id);
 977
 978                 let mut encoded_refund = Vec::new();
 979                 tlv_stream.write(&mut encoded_refund).unwrap();
 980
 981                 let invoice = Refund::try_from(encoded_refund).unwrap()
 982                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
 983                         .unwrap()
 984                         .build().unwrap()
 985                         .sign(recipient_sign).unwrap();
 986                 assert!(invoice.verify(&expanded_key, &secp_ctx).is_err());
 987         }
 988
 989         #[test]
 990         fn builds_refund_with_absolute_expiry() {
 991                 let future_expiry = Duration::from_secs(u64::max_value());
 992                 let past_expiry = Duration::from_secs(0);
 993
 994                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 995                         .absolute_expiry(future_expiry)
 996                         .build()
 997                         .unwrap();
 998                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 999                 #[cfg(feature = "std")]
1000                 assert!(!refund.is_expired());
1001                 assert_eq!(refund.absolute_expiry(), Some(future_expiry));
1002                 assert_eq!(tlv_stream.absolute_expiry, Some(future_expiry.as_secs()));
1003
1004                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1005                         .absolute_expiry(future_expiry)
1006                         .absolute_expiry(past_expiry)
1007                         .build()
1008                         .unwrap();
1009                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1010                 #[cfg(feature = "std")]
1011                 assert!(refund.is_expired());
1012                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
1013                 assert_eq!(tlv_stream.absolute_expiry, Some(past_expiry.as_secs()));
1014         }
1015
1016         #[test]
1017         fn builds_refund_with_paths() {
1018                 let paths = vec![
1019                         BlindedPath {
1020                                 introduction_node_id: pubkey(40),
1021                                 blinding_point: pubkey(41),
1022                                 blinded_hops: vec![
1023                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1024                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1025                                 ],
1026                         },
1027                         BlindedPath {
1028                                 introduction_node_id: pubkey(40),
1029                                 blinding_point: pubkey(41),
1030                                 blinded_hops: vec![
1031                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1032                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1033                                 ],
1034                         },
1035                 ];
1036
1037                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1038                         .path(paths[0].clone())
1039                         .path(paths[1].clone())
1040                         .build()
1041                         .unwrap();
1042                 let (_, offer_tlv_stream, invoice_request_tlv_stream) = refund.as_tlv_stream();
1043                 assert_eq!(refund.paths(), paths.as_slice());
1044                 assert_eq!(refund.payer_id(), pubkey(42));
1045                 assert_ne!(pubkey(42), pubkey(44));
1046                 assert_eq!(offer_tlv_stream.paths, Some(&paths));
1047                 assert_eq!(invoice_request_tlv_stream.payer_id, Some(&pubkey(42)));
1048         }
1049
1050         #[test]
1051         fn builds_refund_with_issuer() {
1052                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1053                         .issuer("bar".into())
1054                         .build()
1055                         .unwrap();
1056                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1057                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
1058                 assert_eq!(tlv_stream.issuer, Some(&String::from("bar")));
1059
1060                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1061                         .issuer("bar".into())
1062                         .issuer("baz".into())
1063                         .build()
1064                         .unwrap();
1065                 let (_, tlv_stream, _) = refund.as_tlv_stream();
1066                 assert_eq!(refund.issuer(), Some(PrintableString("baz")));
1067                 assert_eq!(tlv_stream.issuer, Some(&String::from("baz")));
1068         }
1069
1070         #[test]
1071         fn builds_refund_with_chain() {
1072                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
1073                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
1074
1075                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1076                         .chain(Network::Bitcoin)
1077                         .build().unwrap();
1078                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1079                 assert_eq!(refund.chain(), mainnet);
1080                 assert_eq!(tlv_stream.chain, None);
1081
1082                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1083                         .chain(Network::Testnet)
1084                         .build().unwrap();
1085                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1086                 assert_eq!(refund.chain(), testnet);
1087                 assert_eq!(tlv_stream.chain, Some(&testnet));
1088
1089                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1090                         .chain(Network::Regtest)
1091                         .chain(Network::Testnet)
1092                         .build().unwrap();
1093                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1094                 assert_eq!(refund.chain(), testnet);
1095                 assert_eq!(tlv_stream.chain, Some(&testnet));
1096         }
1097
1098         #[test]
1099         fn builds_refund_with_quantity() {
1100                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1101                         .quantity(10)
1102                         .build().unwrap();
1103                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1104                 assert_eq!(refund.quantity(), Some(10));
1105                 assert_eq!(tlv_stream.quantity, Some(10));
1106
1107                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1108                         .quantity(10)
1109                         .quantity(1)
1110                         .build().unwrap();
1111                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1112                 assert_eq!(refund.quantity(), Some(1));
1113                 assert_eq!(tlv_stream.quantity, Some(1));
1114         }
1115
1116         #[test]
1117         fn builds_refund_with_payer_note() {
1118                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1119                         .payer_note("bar".into())
1120                         .build().unwrap();
1121                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1122                 assert_eq!(refund.payer_note(), Some(PrintableString("bar")));
1123                 assert_eq!(tlv_stream.payer_note, Some(&String::from("bar")));
1124
1125                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1126                         .payer_note("bar".into())
1127                         .payer_note("baz".into())
1128                         .build().unwrap();
1129                 let (_, _, tlv_stream) = refund.as_tlv_stream();
1130                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
1131                 assert_eq!(tlv_stream.payer_note, Some(&String::from("baz")));
1132         }
1133
1134         #[test]
1135         fn fails_responding_with_unknown_required_features() {
1136                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1137                         .features_unchecked(InvoiceRequestFeatures::unknown())
1138                         .build().unwrap()
1139                         .respond_with_no_std(payment_paths(), payment_hash(), recipient_pubkey(), now())
1140                 {
1141                         Ok(_) => panic!("expected error"),
1142                         Err(e) => assert_eq!(e, Bolt12SemanticError::UnknownRequiredFeatures),
1143                 }
1144         }
1145
1146         #[test]
1147         fn parses_refund_with_metadata() {
1148                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1149                         .build().unwrap();
1150                 if let Err(e) = refund.to_string().parse::<Refund>() {
1151                         panic!("error parsing refund: {:?}", e);
1152                 }
1153
1154                 let mut tlv_stream = refund.as_tlv_stream();
1155                 tlv_stream.0.metadata = None;
1156
1157                 match Refund::try_from(tlv_stream.to_bytes()) {
1158                         Ok(_) => panic!("expected error"),
1159                         Err(e) => {
1160                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingPayerMetadata));
1161                         },
1162                 }
1163         }
1164
1165         #[test]
1166         fn parses_refund_with_description() {
1167                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1168                         .build().unwrap();
1169                 if let Err(e) = refund.to_string().parse::<Refund>() {
1170                         panic!("error parsing refund: {:?}", e);
1171                 }
1172
1173                 let mut tlv_stream = refund.as_tlv_stream();
1174                 tlv_stream.1.description = None;
1175
1176                 match Refund::try_from(tlv_stream.to_bytes()) {
1177                         Ok(_) => panic!("expected error"),
1178                         Err(e) => {
1179                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingDescription));
1180                         },
1181                 }
1182         }
1183
1184         #[test]
1185         fn parses_refund_with_amount() {
1186                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1187                         .build().unwrap();
1188                 if let Err(e) = refund.to_string().parse::<Refund>() {
1189                         panic!("error parsing refund: {:?}", e);
1190                 }
1191
1192                 let mut tlv_stream = refund.as_tlv_stream();
1193                 tlv_stream.2.amount = None;
1194
1195                 match Refund::try_from(tlv_stream.to_bytes()) {
1196                         Ok(_) => panic!("expected error"),
1197                         Err(e) => {
1198                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingAmount));
1199                         },
1200                 }
1201
1202                 let mut tlv_stream = refund.as_tlv_stream();
1203                 tlv_stream.2.amount = Some(MAX_VALUE_MSAT + 1);
1204
1205                 match Refund::try_from(tlv_stream.to_bytes()) {
1206                         Ok(_) => panic!("expected error"),
1207                         Err(e) => {
1208                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InvalidAmount));
1209                         },
1210                 }
1211         }
1212
1213         #[test]
1214         fn parses_refund_with_payer_id() {
1215                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1216                         .build().unwrap();
1217                 if let Err(e) = refund.to_string().parse::<Refund>() {
1218                         panic!("error parsing refund: {:?}", e);
1219                 }
1220
1221                 let mut tlv_stream = refund.as_tlv_stream();
1222                 tlv_stream.2.payer_id = None;
1223
1224                 match Refund::try_from(tlv_stream.to_bytes()) {
1225                         Ok(_) => panic!("expected error"),
1226                         Err(e) => {
1227                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingPayerId));
1228                         },
1229                 }
1230         }
1231
1232         #[test]
1233         fn parses_refund_with_optional_fields() {
1234                 let past_expiry = Duration::from_secs(0);
1235                 let paths = vec![
1236                         BlindedPath {
1237                                 introduction_node_id: pubkey(40),
1238                                 blinding_point: pubkey(41),
1239                                 blinded_hops: vec![
1240                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
1241                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
1242                                 ],
1243                         },
1244                         BlindedPath {
1245                                 introduction_node_id: pubkey(40),
1246                                 blinding_point: pubkey(41),
1247                                 blinded_hops: vec![
1248                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
1249                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
1250                                 ],
1251                         },
1252                 ];
1253
1254                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1255                         .absolute_expiry(past_expiry)
1256                         .issuer("bar".into())
1257                         .path(paths[0].clone())
1258                         .path(paths[1].clone())
1259                         .chain(Network::Testnet)
1260                         .features_unchecked(InvoiceRequestFeatures::unknown())
1261                         .quantity(10)
1262                         .payer_note("baz".into())
1263                         .build()
1264                         .unwrap();
1265                 match refund.to_string().parse::<Refund>() {
1266                         Ok(refund) => {
1267                                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
1268                                 #[cfg(feature = "std")]
1269                                 assert!(refund.is_expired());
1270                                 assert_eq!(refund.paths(), &paths[..]);
1271                                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
1272                                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Testnet));
1273                                 assert_eq!(refund.features(), &InvoiceRequestFeatures::unknown());
1274                                 assert_eq!(refund.quantity(), Some(10));
1275                                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
1276                         },
1277                         Err(e) => panic!("error parsing refund: {:?}", e),
1278                 }
1279         }
1280
1281         #[test]
1282         fn fails_parsing_refund_with_unexpected_fields() {
1283                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
1284                         .build().unwrap();
1285                 if let Err(e) = refund.to_string().parse::<Refund>() {
1286                         panic!("error parsing refund: {:?}", e);
1287                 }
1288
1289                 let metadata = vec![42; 32];
1290                 let mut tlv_stream = refund.as_tlv_stream();
1291                 tlv_stream.1.metadata = Some(&metadata);
1292
1293                 match Refund::try_from(tlv_stream.to_bytes()) {
1294                         Ok(_) => panic!("expected error"),
1295                         Err(e) => {
1296                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedMetadata));
1297                         },
1298                 }
1299
1300                 let chains = vec![ChainHash::using_genesis_block(Network::Testnet)];
1301                 let mut tlv_stream = refund.as_tlv_stream();
1302                 tlv_stream.1.chains = Some(&chains);
1303
1304                 match Refund::try_from(tlv_stream.to_bytes()) {
1305                         Ok(_) => panic!("expected error"),
1306                         Err(e) => {
1307                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedChain));
1308                         },
1309                 }
1310
1311                 let mut tlv_stream = refund.as_tlv_stream();
1312                 tlv_stream.1.currency = Some(&b"USD");
1313                 tlv_stream.1.amount = Some(1000);
1314
1315                 match Refund::try_from(tlv_stream.to_bytes()) {
1316                         Ok(_) => panic!("expected error"),
1317                         Err(e) => {
1318                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedAmount));
1319                         },
1320                 }
1321
1322                 let features = OfferFeatures::unknown();
1323                 let mut tlv_stream = refund.as_tlv_stream();
1324                 tlv_stream.1.features = Some(&features);
1325
1326                 match Refund::try_from(tlv_stream.to_bytes()) {
1327                         Ok(_) => panic!("expected error"),
1328                         Err(e) => {
1329                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedFeatures));
1330                         },
1331                 }
1332
1333                 let mut tlv_stream = refund.as_tlv_stream();
1334                 tlv_stream.1.quantity_max = Some(10);
1335
1336                 match Refund::try_from(tlv_stream.to_bytes()) {
1337                         Ok(_) => panic!("expected error"),
1338                         Err(e) => {
1339                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedQuantity));
1340                         },
1341                 }
1342
1343                 let node_id = payer_pubkey();
1344                 let mut tlv_stream = refund.as_tlv_stream();
1345                 tlv_stream.1.node_id = Some(&node_id);
1346
1347                 match Refund::try_from(tlv_stream.to_bytes()) {
1348                         Ok(_) => panic!("expected error"),
1349                         Err(e) => {
1350                                 assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::UnexpectedSigningPubkey));
1351                         },
1352                 }
1353         }
1354
1355         #[test]
1356         fn fails_parsing_refund_with_extra_tlv_records() {
1357                 let secp_ctx = Secp256k1::new();
1358                 let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
1359                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], keys.public_key(), 1000).unwrap()
1360                         .build().unwrap();
1361
1362                 let mut encoded_refund = Vec::new();
1363                 refund.write(&mut encoded_refund).unwrap();
1364                 BigSize(1002).write(&mut encoded_refund).unwrap();
1365                 BigSize(32).write(&mut encoded_refund).unwrap();
1366                 [42u8; 32].write(&mut encoded_refund).unwrap();
1367
1368                 match Refund::try_from(encoded_refund) {
1369                         Ok(_) => panic!("expected error"),
1370                         Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
1371                 }
1372         }
1373 }