git.bitcoin.ninja 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 an [`Invoice`] to be paid.
  14 //!
  15 //! This is an [`InvoiceRequest`] produced *not* in response to an [`Offer`].
  16 //!
  17 //! [`Invoice`]: crate::offers::invoice::Invoice
  18 //! [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
  19 //! [`Offer`]: crate::offers::offer::Offer
  20 //!
  21 //! ```ignore
  22 //! extern crate bitcoin;
  23 //! extern crate core;
  24 //! extern crate lightning;
  25 //!
  26 //! use core::convert::TryFrom;
  27 //! use core::time::Duration;
  28 //!
  29 //! use bitcoin::network::constants::Network;
  30 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
  31 //! use lightning::offers::parse::ParseError;
  32 //! use lightning::offers::refund::{Refund, RefundBuilder};
  33 //! use lightning::util::ser::{Readable, Writeable};
  34 //!
  35 //! # use lightning::onion_message::BlindedPath;
  36 //! # #[cfg(feature = "std")]
  37 //! # use std::time::SystemTime;
  38 //! #
  39 //! # fn create_blinded_path() -> BlindedPath { unimplemented!() }
  40 //! # fn create_another_blinded_path() -> BlindedPath { unimplemented!() }
  41 //! #
  42 //! # #[cfg(feature = "std")]
  43 //! # fn build() -> Result<(), ParseError> {
  44 //! let secp_ctx = Secp256k1::new();
  45 //! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
  46 //! let pubkey = PublicKey::from(keys);
  47 //!
  48 //! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
  49 //! let refund = RefundBuilder::new("coffee, large".to_string(), vec![1; 32], pubkey, 20_000)?
  50 //!     .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
  51 //!     .issuer("Foo Bar".to_string())
  52 //!     .path(create_blinded_path())
  53 //!     .path(create_another_blinded_path())
  54 //!     .chain(Network::Bitcoin)
  55 //!     .payer_note("refund for order #12345".to_string())
  56 //!     .build()?;
  57 //!
  58 //! // Encode as a bech32 string for use in a QR code.
  59 //! let encoded_refund = refund.to_string();
  60 //!
  61 //! // Parse from a bech32 string after scanning from a QR code.
  62 //! let refund = encoded_refund.parse::<Refund>()?;
  63 //!
  64 //! // Encode refund as raw bytes.
  65 //! let mut bytes = Vec::new();
  66 //! refund.write(&mut bytes).unwrap();
  67 //!
  68 //! // Decode raw bytes into an refund.
  69 //! let refund = Refund::try_from(bytes)?;
  70 //! # Ok(())
  71 //! # }
  72 //! ```
  73
  74 use bitcoin::blockdata::constants::ChainHash;
  75 use bitcoin::network::constants::Network;
  76 use bitcoin::secp256k1::PublicKey;
  77 use core::convert::TryFrom;
  78 use core::str::FromStr;
  79 use core::time::Duration;
  80 use crate::io;
  81 use crate::ln::PaymentHash;
  82 use crate::ln::features::InvoiceRequestFeatures;
  83 use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
  84 use crate::offers::invoice::{BlindedPayInfo, InvoiceBuilder};
  85 use crate::offers::invoice_request::{InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef};
  86 use crate::offers::offer::{OfferTlvStream, OfferTlvStreamRef};
  87 use crate::offers::parse::{Bech32Encode, ParseError, ParsedMessage, SemanticError};
  88 use crate::offers::payer::{PayerContents, PayerTlvStream, PayerTlvStreamRef};
  89 use crate::onion_message::BlindedPath;
  90 use crate::util::ser::{SeekReadable, WithoutLength, Writeable, Writer};
  91 use crate::util::string::PrintableString;
  92
  93 use crate::prelude::*;
  94
  95 #[cfg(feature = "std")]
  96 use std::time::SystemTime;
  97
  98 /// Builds a [`Refund`] for the "offer for money" flow.
  99 ///
 100 /// See [module-level documentation] for usage.
 101 ///
 102 /// [module-level documentation]: self
 103 pub struct RefundBuilder {
 104         refund: RefundContents,
 105 }
 106
 107 impl RefundBuilder {
 108         /// Creates a new builder for a refund using the [`Refund::payer_id`] for the public node id to
 109         /// send to if no [`Refund::paths`] are set. Otherwise, it may be a transient pubkey.
 110         ///
 111         /// Additionally, sets the required [`Refund::description`], [`Refund::metadata`], and
 112         /// [`Refund::amount_msats`].
 113         pub fn new(
 114                 description: String, metadata: Vec<u8>, payer_id: PublicKey, amount_msats: u64
 115         ) -> Result<Self, SemanticError> {
 116                 if amount_msats > MAX_VALUE_MSAT {
 117                         return Err(SemanticError::InvalidAmount);
 118                 }
 119
 120                 let refund = RefundContents {
 121                         payer: PayerContents(metadata), description, absolute_expiry: None, issuer: None,
 122                         paths: None, chain: None, amount_msats, features: InvoiceRequestFeatures::empty(),
 123                         quantity: None, payer_id, payer_note: None,
 124                 };
 125
 126                 Ok(RefundBuilder { refund })
 127         }
 128
 129         /// Sets the [`Refund::absolute_expiry`] as seconds since the Unix epoch. Any expiry that has
 130         /// already passed is valid and can be checked for using [`Refund::is_expired`].
 131         ///
 132         /// Successive calls to this method will override the previous setting.
 133         pub fn absolute_expiry(mut self, absolute_expiry: Duration) -> Self {
 134                 self.refund.absolute_expiry = Some(absolute_expiry);
 135                 self
 136         }
 137
 138         /// Sets the [`Refund::issuer`].
 139         ///
 140         /// Successive calls to this method will override the previous setting.
 141         pub fn issuer(mut self, issuer: String) -> Self {
 142                 self.refund.issuer = Some(issuer);
 143                 self
 144         }
 145
 146         /// Adds a blinded path to [`Refund::paths`]. Must include at least one path if only connected
 147         /// by private channels or if [`Refund::payer_id`] is not a public node id.
 148         ///
 149         /// Successive calls to this method will add another blinded path. Caller is responsible for not
 150         /// adding duplicate paths.
 151         pub fn path(mut self, path: BlindedPath) -> Self {
 152                 self.refund.paths.get_or_insert_with(Vec::new).push(path);
 153                 self
 154         }
 155
 156         /// Sets the [`Refund::chain`] of the given [`Network`] for paying an invoice. If not
 157         /// called, [`Network::Bitcoin`] is assumed.
 158         ///
 159         /// Successive calls to this method will override the previous setting.
 160         pub fn chain(mut self, network: Network) -> Self {
 161                 self.refund.chain = Some(ChainHash::using_genesis_block(network));
 162                 self
 163         }
 164
 165         /// Sets [`Refund::quantity`] of items. This is purely for informational purposes. It is useful
 166         /// when the refund pertains to an [`Invoice`] that paid for more than one item from an
 167         /// [`Offer`] as specified by [`InvoiceRequest::quantity`].
 168         ///
 169         /// Successive calls to this method will override the previous setting.
 170         ///
 171         /// [`Invoice`]: crate::offers::invoice::Invoice
 172         /// [`InvoiceRequest::quantity`]: crate::offers::invoice_request::InvoiceRequest::quantity
 173         /// [`Offer`]: crate::offers::offer::Offer
 174         pub fn quantity(mut self, quantity: u64) -> Self {
 175                 self.refund.quantity = Some(quantity);
 176                 self
 177         }
 178
 179         /// Sets the [`Refund::payer_note`].
 180         ///
 181         /// Successive calls to this method will override the previous setting.
 182         pub fn payer_note(mut self, payer_note: String) -> Self {
 183                 self.refund.payer_note = Some(payer_note);
 184                 self
 185         }
 186
 187         /// Builds a [`Refund`] after checking for valid semantics.
 188         pub fn build(mut self) -> Result<Refund, SemanticError> {
 189                 if self.refund.chain() == self.refund.implied_chain() {
 190                         self.refund.chain = None;
 191                 }
 192
 193                 let mut bytes = Vec::new();
 194                 self.refund.write(&mut bytes).unwrap();
 195
 196                 Ok(Refund {
 197                         bytes,
 198                         contents: self.refund,
 199                 })
 200         }
 201 }
 202
 203 #[cfg(test)]
 204 impl RefundBuilder {
 205         fn features_unchecked(mut self, features: InvoiceRequestFeatures) -> Self {
 206                 self.refund.features = features;
 207                 self
 208         }
 209 }
 210
 211 /// A `Refund` is a request to send an [`Invoice`] without a preceding [`Offer`].
 212 ///
 213 /// Typically, after an invoice is paid, the recipient may publish a refund allowing the sender to
 214 /// recoup their funds. A refund may be used more generally as an "offer for money", such as with a
 215 /// bitcoin ATM.
 216 ///
 217 /// [`Invoice`]: crate::offers::invoice::Invoice
 218 /// [`Offer`]: crate::offers::offer::Offer
 219 #[derive(Clone, Debug)]
 220 pub struct Refund {
 221         pub(super) bytes: Vec<u8>,
 222         pub(super) contents: RefundContents,
 223 }
 224
 225 /// The contents of a [`Refund`], which may be shared with an [`Invoice`].
 226 ///
 227 /// [`Invoice`]: crate::offers::invoice::Invoice
 228 #[derive(Clone, Debug)]
 229 pub(super) struct RefundContents {
 230         payer: PayerContents,
 231         // offer fields
 232         description: String,
 233         absolute_expiry: Option<Duration>,
 234         issuer: Option<String>,
 235         paths: Option<Vec<BlindedPath>>,
 236         // invoice_request fields
 237         chain: Option<ChainHash>,
 238         amount_msats: u64,
 239         features: InvoiceRequestFeatures,
 240         quantity: Option<u64>,
 241         payer_id: PublicKey,
 242         payer_note: Option<String>,
 243 }
 244
 245 impl Refund {
 246         /// A complete description of the purpose of the refund. Intended to be displayed to the user
 247         /// but with the caveat that it has not been verified in any way.
 248         pub fn description(&self) -> PrintableString {
 249                 PrintableString(&self.contents.description)
 250         }
 251
 252         /// Duration since the Unix epoch when an invoice should no longer be sent.
 253         ///
 254         /// If `None`, the refund does not expire.
 255         pub fn absolute_expiry(&self) -> Option<Duration> {
 256                 self.contents.absolute_expiry
 257         }
 258
 259         /// Whether the refund has expired.
 260         #[cfg(feature = "std")]
 261         pub fn is_expired(&self) -> bool {
 262                 self.contents.is_expired()
 263         }
 264
 265         /// The issuer of the refund, possibly beginning with `user@domain` or `domain`. Intended to be
 266         /// displayed to the user but with the caveat that it has not been verified in any way.
 267         pub fn issuer(&self) -> Option<PrintableString> {
 268                 self.contents.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
 269         }
 270
 271         /// Paths to the sender originating from publicly reachable nodes. Blinded paths provide sender
 272         /// privacy by obfuscating its node id.
 273         pub fn paths(&self) -> &[BlindedPath] {
 274                 self.contents.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
 275         }
 276
 277         /// An unpredictable series of bytes, typically containing information about the derivation of
 278         /// [`payer_id`].
 279         ///
 280         /// [`payer_id`]: Self::payer_id
 281         pub fn metadata(&self) -> &[u8] {
 282                 &self.contents.payer.0
 283         }
 284
 285         /// A chain that the refund is valid for.
 286         pub fn chain(&self) -> ChainHash {
 287                 self.contents.chain.unwrap_or_else(|| self.contents.implied_chain())
 288         }
 289
 290         /// The amount to refund in msats (i.e., the minimum lightning-payable unit for [`chain`]).
 291         ///
 292         /// [`chain`]: Self::chain
 293         pub fn amount_msats(&self) -> u64 {
 294                 self.contents.amount_msats
 295         }
 296
 297         /// Features pertaining to requesting an invoice.
 298         pub fn features(&self) -> &InvoiceRequestFeatures {
 299                 &self.contents.features
 300         }
 301
 302         /// The quantity of an item that refund is for.
 303         pub fn quantity(&self) -> Option<u64> {
 304                 self.contents.quantity
 305         }
 306
 307         /// A public node id to send to in the case where there are no [`paths`]. Otherwise, a possibly
 308         /// transient pubkey.
 309         ///
 310         /// [`paths`]: Self::paths
 311         pub fn payer_id(&self) -> PublicKey {
 312                 self.contents.payer_id
 313         }
 314
 315         /// Payer provided note to include in the invoice.
 316         pub fn payer_note(&self) -> Option<PrintableString> {
 317                 self.contents.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
 318         }
 319
 320         /// Creates an [`Invoice`] for the refund with the given required fields.
 321         ///
 322         /// Unless [`InvoiceBuilder::relative_expiry`] is set, the invoice will expire two hours after
 323         /// calling this method in `std` builds. For `no-std` builds, a final [`Duration`] parameter
 324         /// must be given, which is used to set [`Invoice::created_at`] since [`std::time::SystemTime`]
 325         /// is not available.
 326         ///
 327         /// The caller is expected to remember the preimage of `payment_hash` in order to
 328         /// claim a payment for the invoice.
 329         ///
 330         /// The `signing_pubkey` is required to sign the invoice since refunds are not in response to an
 331         /// offer, which does have a `signing_pubkey`.
 332         ///
 333         /// The `payment_paths` parameter is useful for maintaining the payment recipient's privacy. It
 334         /// must contain one or more elements.
 335         ///
 336         /// Errors if the request contains unknown required features.
 337         ///
 338         /// [`Invoice`]: crate::offers::invoice::Invoice
 339         /// [`Invoice::created_at`]: crate::offers::invoice::Invoice::created_at
 340         pub fn respond_with(
 341                 &self, payment_paths: Vec<(BlindedPath, BlindedPayInfo)>, payment_hash: PaymentHash,
 342                 signing_pubkey: PublicKey,
 343                 #[cfg(any(test, not(feature = "std")))]
 344                 created_at: Duration
 345         ) -> Result<InvoiceBuilder, SemanticError> {
 346                 if self.features().requires_unknown_bits() {
 347                         return Err(SemanticError::UnknownRequiredFeatures);
 348                 }
 349
 350                 #[cfg(all(not(test), feature = "std"))]
 351                 let created_at = std::time::SystemTime::now()
 352                         .duration_since(std::time::SystemTime::UNIX_EPOCH)
 353                         .expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 354
 355                 InvoiceBuilder::for_refund(self, payment_paths, created_at, payment_hash, signing_pubkey)
 356         }
 357
 358         #[cfg(test)]
 359         fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 360                 self.contents.as_tlv_stream()
 361         }
 362 }
 363
 364 impl AsRef<[u8]> for Refund {
 365         fn as_ref(&self) -> &[u8] {
 366                 &self.bytes
 367         }
 368 }
 369
 370 impl RefundContents {
 371         #[cfg(feature = "std")]
 372         pub(super) fn is_expired(&self) -> bool {
 373                 match self.absolute_expiry {
 374                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
 375                                 Ok(elapsed) => elapsed > seconds_from_epoch,
 376                                 Err(_) => false,
 377                         },
 378                         None => false,
 379                 }
 380         }
 381
 382         pub(super) fn chain(&self) -> ChainHash {
 383                 self.chain.unwrap_or_else(|| self.implied_chain())
 384         }
 385
 386         pub fn implied_chain(&self) -> ChainHash {
 387                 ChainHash::using_genesis_block(Network::Bitcoin)
 388         }
 389
 390         pub(super) fn as_tlv_stream(&self) -> RefundTlvStreamRef {
 391                 let payer = PayerTlvStreamRef {
 392                         metadata: Some(&self.payer.0),
 393                 };
 394
 395                 let offer = OfferTlvStreamRef {
 396                         chains: None,
 397                         metadata: None,
 398                         currency: None,
 399                         amount: None,
 400                         description: Some(&self.description),
 401                         features: None,
 402                         absolute_expiry: self.absolute_expiry.map(|duration| duration.as_secs()),
 403                         paths: self.paths.as_ref(),
 404                         issuer: self.issuer.as_ref(),
 405                         quantity_max: None,
 406                         node_id: None,
 407                 };
 408
 409                 let features = {
 410                         if self.features == InvoiceRequestFeatures::empty() { None }
 411                         else { Some(&self.features) }
 412                 };
 413
 414                 let invoice_request = InvoiceRequestTlvStreamRef {
 415                         chain: self.chain.as_ref(),
 416                         amount: Some(self.amount_msats),
 417                         features,
 418                         quantity: self.quantity,
 419                         payer_id: Some(&self.payer_id),
 420                         payer_note: self.payer_note.as_ref(),
 421                 };
 422
 423                 (payer, offer, invoice_request)
 424         }
 425 }
 426
 427 impl Writeable for Refund {
 428         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 429                 WithoutLength(&self.bytes).write(writer)
 430         }
 431 }
 432
 433 impl Writeable for RefundContents {
 434         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 435                 self.as_tlv_stream().write(writer)
 436         }
 437 }
 438
 439 type RefundTlvStream = (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream);
 440
 441 type RefundTlvStreamRef<'a> = (
 442         PayerTlvStreamRef<'a>,
 443         OfferTlvStreamRef<'a>,
 444         InvoiceRequestTlvStreamRef<'a>,
 445 );
 446
 447 impl SeekReadable for RefundTlvStream {
 448         fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
 449                 let payer = SeekReadable::read(r)?;
 450                 let offer = SeekReadable::read(r)?;
 451                 let invoice_request = SeekReadable::read(r)?;
 452
 453                 Ok((payer, offer, invoice_request))
 454         }
 455 }
 456
 457 impl Bech32Encode for Refund {
 458         const BECH32_HRP: &'static str = "lnr";
 459 }
 460
 461 impl FromStr for Refund {
 462         type Err = ParseError;
 463
 464         fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err> {
 465                 Refund::from_bech32_str(s)
 466         }
 467 }
 468
 469 impl TryFrom<Vec<u8>> for Refund {
 470         type Error = ParseError;
 471
 472         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 473                 let refund = ParsedMessage::<RefundTlvStream>::try_from(bytes)?;
 474                 let ParsedMessage { bytes, tlv_stream } = refund;
 475                 let contents = RefundContents::try_from(tlv_stream)?;
 476
 477                 Ok(Refund { bytes, contents })
 478         }
 479 }
 480
 481 impl TryFrom<RefundTlvStream> for RefundContents {
 482         type Error = SemanticError;
 483
 484         fn try_from(tlv_stream: RefundTlvStream) -> Result<Self, Self::Error> {
 485                 let (
 486                         PayerTlvStream { metadata: payer_metadata },
 487                         OfferTlvStream {
 488                                 chains, metadata, currency, amount: offer_amount, description,
 489                                 features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
 490                         },
 491                         InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
 492                 ) = tlv_stream;
 493
 494                 let payer = match payer_metadata {
 495                         None => return Err(SemanticError::MissingPayerMetadata),
 496                         Some(metadata) => PayerContents(metadata),
 497                 };
 498
 499                 if metadata.is_some() {
 500                         return Err(SemanticError::UnexpectedMetadata);
 501                 }
 502
 503                 if chains.is_some() {
 504                         return Err(SemanticError::UnexpectedChain);
 505                 }
 506
 507                 if currency.is_some() || offer_amount.is_some() {
 508                         return Err(SemanticError::UnexpectedAmount);
 509                 }
 510
 511                 let description = match description {
 512                         None => return Err(SemanticError::MissingDescription),
 513                         Some(description) => description,
 514                 };
 515
 516                 if offer_features.is_some() {
 517                         return Err(SemanticError::UnexpectedFeatures);
 518                 }
 519
 520                 let absolute_expiry = absolute_expiry.map(Duration::from_secs);
 521
 522                 if quantity_max.is_some() {
 523                         return Err(SemanticError::UnexpectedQuantity);
 524                 }
 525
 526                 if node_id.is_some() {
 527                         return Err(SemanticError::UnexpectedSigningPubkey);
 528                 }
 529
 530                 let amount_msats = match amount {
 531                         None => return Err(SemanticError::MissingAmount),
 532                         Some(amount_msats) if amount_msats > MAX_VALUE_MSAT => {
 533                                 return Err(SemanticError::InvalidAmount);
 534                         },
 535                         Some(amount_msats) => amount_msats,
 536                 };
 537
 538                 let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
 539
 540                 let payer_id = match payer_id {
 541                         None => return Err(SemanticError::MissingPayerId),
 542                         Some(payer_id) => payer_id,
 543                 };
 544
 545                 Ok(RefundContents {
 546                         payer, description, absolute_expiry, issuer, paths, chain, amount_msats, features,
 547                         quantity, payer_id, payer_note,
 548                 })
 549         }
 550 }
 551
 552 impl core::fmt::Display for Refund {
 553         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 554                 self.fmt_bech32_str(f)
 555         }
 556 }
 557
 558 #[cfg(test)]
 559 mod tests {
 560         use super::{Refund, RefundBuilder, RefundTlvStreamRef};
 561
 562         use bitcoin::blockdata::constants::ChainHash;
 563         use bitcoin::network::constants::Network;
 564         use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
 565         use core::convert::TryFrom;
 566         use core::time::Duration;
 567         use crate::ln::features::{InvoiceRequestFeatures, OfferFeatures};
 568         use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 569         use crate::offers::invoice_request::InvoiceRequestTlvStreamRef;
 570         use crate::offers::offer::OfferTlvStreamRef;
 571         use crate::offers::parse::{ParseError, SemanticError};
 572         use crate::offers::payer::PayerTlvStreamRef;
 573         use crate::onion_message::{BlindedHop, BlindedPath};
 574         use crate::util::ser::{BigSize, Writeable};
 575         use crate::util::string::PrintableString;
 576
 577         fn payer_pubkey() -> PublicKey {
 578                 let secp_ctx = Secp256k1::new();
 579                 KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()).public_key()
 580         }
 581
 582         fn pubkey(byte: u8) -> PublicKey {
 583                 let secp_ctx = Secp256k1::new();
 584                 PublicKey::from_secret_key(&secp_ctx, &privkey(byte))
 585         }
 586
 587         fn privkey(byte: u8) -> SecretKey {
 588                 SecretKey::from_slice(&[byte; 32]).unwrap()
 589         }
 590
 591         trait ToBytes {
 592                 fn to_bytes(&self) -> Vec<u8>;
 593         }
 594
 595         impl<'a> ToBytes for RefundTlvStreamRef<'a> {
 596                 fn to_bytes(&self) -> Vec<u8> {
 597                         let mut buffer = Vec::new();
 598                         self.write(&mut buffer).unwrap();
 599                         buffer
 600                 }
 601         }
 602
 603         #[test]
 604         fn builds_refund_with_defaults() {
 605                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 606                         .build().unwrap();
 607
 608                 let mut buffer = Vec::new();
 609                 refund.write(&mut buffer).unwrap();
 610
 611                 assert_eq!(refund.bytes, buffer.as_slice());
 612                 assert_eq!(refund.metadata(), &[1; 32]);
 613                 assert_eq!(refund.description(), PrintableString("foo"));
 614                 assert_eq!(refund.absolute_expiry(), None);
 615                 #[cfg(feature = "std")]
 616                 assert!(!refund.is_expired());
 617                 assert_eq!(refund.paths(), &[]);
 618                 assert_eq!(refund.issuer(), None);
 619                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Bitcoin));
 620                 assert_eq!(refund.amount_msats(), 1000);
 621                 assert_eq!(refund.features(), &InvoiceRequestFeatures::empty());
 622                 assert_eq!(refund.payer_id(), payer_pubkey());
 623                 assert_eq!(refund.payer_note(), None);
 624
 625                 assert_eq!(
 626                         refund.as_tlv_stream(),
 627                         (
 628                                 PayerTlvStreamRef { metadata: Some(&vec![1; 32]) },
 629                                 OfferTlvStreamRef {
 630                                         chains: None,
 631                                         metadata: None,
 632                                         currency: None,
 633                                         amount: None,
 634                                         description: Some(&String::from("foo")),
 635                                         features: None,
 636                                         absolute_expiry: None,
 637                                         paths: None,
 638                                         issuer: None,
 639                                         quantity_max: None,
 640                                         node_id: None,
 641                                 },
 642                                 InvoiceRequestTlvStreamRef {
 643                                         chain: None,
 644                                         amount: Some(1000),
 645                                         features: None,
 646                                         quantity: None,
 647                                         payer_id: Some(&payer_pubkey()),
 648                                         payer_note: None,
 649                                 },
 650                         ),
 651                 );
 652
 653                 if let Err(e) = Refund::try_from(buffer) {
 654                         panic!("error parsing refund: {:?}", e);
 655                 }
 656         }
 657
 658         #[test]
 659         fn fails_building_refund_with_invalid_amount() {
 660                 match RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), MAX_VALUE_MSAT + 1) {
 661                         Ok(_) => panic!("expected error"),
 662                         Err(e) => assert_eq!(e, SemanticError::InvalidAmount),
 663                 }
 664         }
 665
 666         #[test]
 667         fn builds_refund_with_absolute_expiry() {
 668                 let future_expiry = Duration::from_secs(u64::max_value());
 669                 let past_expiry = Duration::from_secs(0);
 670
 671                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 672                         .absolute_expiry(future_expiry)
 673                         .build()
 674                         .unwrap();
 675                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 676                 #[cfg(feature = "std")]
 677                 assert!(!refund.is_expired());
 678                 assert_eq!(refund.absolute_expiry(), Some(future_expiry));
 679                 assert_eq!(tlv_stream.absolute_expiry, Some(future_expiry.as_secs()));
 680
 681                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 682                         .absolute_expiry(future_expiry)
 683                         .absolute_expiry(past_expiry)
 684                         .build()
 685                         .unwrap();
 686                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 687                 #[cfg(feature = "std")]
 688                 assert!(refund.is_expired());
 689                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
 690                 assert_eq!(tlv_stream.absolute_expiry, Some(past_expiry.as_secs()));
 691         }
 692
 693         #[test]
 694         fn builds_refund_with_paths() {
 695                 let paths = vec![
 696                         BlindedPath {
 697                                 introduction_node_id: pubkey(40),
 698                                 blinding_point: pubkey(41),
 699                                 blinded_hops: vec![
 700                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
 701                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
 702                                 ],
 703                         },
 704                         BlindedPath {
 705                                 introduction_node_id: pubkey(40),
 706                                 blinding_point: pubkey(41),
 707                                 blinded_hops: vec![
 708                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
 709                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
 710                                 ],
 711                         },
 712                 ];
 713
 714                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 715                         .path(paths[0].clone())
 716                         .path(paths[1].clone())
 717                         .build()
 718                         .unwrap();
 719                 let (_, offer_tlv_stream, invoice_request_tlv_stream) = refund.as_tlv_stream();
 720                 assert_eq!(refund.paths(), paths.as_slice());
 721                 assert_eq!(refund.payer_id(), pubkey(42));
 722                 assert_ne!(pubkey(42), pubkey(44));
 723                 assert_eq!(offer_tlv_stream.paths, Some(&paths));
 724                 assert_eq!(invoice_request_tlv_stream.payer_id, Some(&pubkey(42)));
 725         }
 726
 727         #[test]
 728         fn builds_refund_with_issuer() {
 729                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 730                         .issuer("bar".into())
 731                         .build()
 732                         .unwrap();
 733                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 734                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
 735                 assert_eq!(tlv_stream.issuer, Some(&String::from("bar")));
 736
 737                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 738                         .issuer("bar".into())
 739                         .issuer("baz".into())
 740                         .build()
 741                         .unwrap();
 742                 let (_, tlv_stream, _) = refund.as_tlv_stream();
 743                 assert_eq!(refund.issuer(), Some(PrintableString("baz")));
 744                 assert_eq!(tlv_stream.issuer, Some(&String::from("baz")));
 745         }
 746
 747         #[test]
 748         fn builds_refund_with_chain() {
 749                 let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
 750                 let testnet = ChainHash::using_genesis_block(Network::Testnet);
 751
 752                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 753                         .chain(Network::Bitcoin)
 754                         .build().unwrap();
 755                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 756                 assert_eq!(refund.chain(), mainnet);
 757                 assert_eq!(tlv_stream.chain, None);
 758
 759                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 760                         .chain(Network::Testnet)
 761                         .build().unwrap();
 762                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 763                 assert_eq!(refund.chain(), testnet);
 764                 assert_eq!(tlv_stream.chain, Some(&testnet));
 765
 766                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 767                         .chain(Network::Regtest)
 768                         .chain(Network::Testnet)
 769                         .build().unwrap();
 770                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 771                 assert_eq!(refund.chain(), testnet);
 772                 assert_eq!(tlv_stream.chain, Some(&testnet));
 773         }
 774
 775         #[test]
 776         fn builds_refund_with_quantity() {
 777                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 778                         .quantity(10)
 779                         .build().unwrap();
 780                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 781                 assert_eq!(refund.quantity(), Some(10));
 782                 assert_eq!(tlv_stream.quantity, Some(10));
 783
 784                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 785                         .quantity(10)
 786                         .quantity(1)
 787                         .build().unwrap();
 788                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 789                 assert_eq!(refund.quantity(), Some(1));
 790                 assert_eq!(tlv_stream.quantity, Some(1));
 791         }
 792
 793         #[test]
 794         fn builds_refund_with_payer_note() {
 795                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 796                         .payer_note("bar".into())
 797                         .build().unwrap();
 798                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 799                 assert_eq!(refund.payer_note(), Some(PrintableString("bar")));
 800                 assert_eq!(tlv_stream.payer_note, Some(&String::from("bar")));
 801
 802                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 803                         .payer_note("bar".into())
 804                         .payer_note("baz".into())
 805                         .build().unwrap();
 806                 let (_, _, tlv_stream) = refund.as_tlv_stream();
 807                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
 808                 assert_eq!(tlv_stream.payer_note, Some(&String::from("baz")));
 809         }
 810
 811         #[test]
 812         fn parses_refund_with_metadata() {
 813                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 814                         .build().unwrap();
 815                 if let Err(e) = refund.to_string().parse::<Refund>() {
 816                         panic!("error parsing refund: {:?}", e);
 817                 }
 818
 819                 let mut tlv_stream = refund.as_tlv_stream();
 820                 tlv_stream.0.metadata = None;
 821
 822                 match Refund::try_from(tlv_stream.to_bytes()) {
 823                         Ok(_) => panic!("expected error"),
 824                         Err(e) => {
 825                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingPayerMetadata));
 826                         },
 827                 }
 828         }
 829
 830         #[test]
 831         fn parses_refund_with_description() {
 832                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 833                         .build().unwrap();
 834                 if let Err(e) = refund.to_string().parse::<Refund>() {
 835                         panic!("error parsing refund: {:?}", e);
 836                 }
 837
 838                 let mut tlv_stream = refund.as_tlv_stream();
 839                 tlv_stream.1.description = None;
 840
 841                 match Refund::try_from(tlv_stream.to_bytes()) {
 842                         Ok(_) => panic!("expected error"),
 843                         Err(e) => {
 844                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingDescription));
 845                         },
 846                 }
 847         }
 848
 849         #[test]
 850         fn parses_refund_with_amount() {
 851                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 852                         .build().unwrap();
 853                 if let Err(e) = refund.to_string().parse::<Refund>() {
 854                         panic!("error parsing refund: {:?}", e);
 855                 }
 856
 857                 let mut tlv_stream = refund.as_tlv_stream();
 858                 tlv_stream.2.amount = None;
 859
 860                 match Refund::try_from(tlv_stream.to_bytes()) {
 861                         Ok(_) => panic!("expected error"),
 862                         Err(e) => {
 863                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingAmount));
 864                         },
 865                 }
 866
 867                 let mut tlv_stream = refund.as_tlv_stream();
 868                 tlv_stream.2.amount = Some(MAX_VALUE_MSAT + 1);
 869
 870                 match Refund::try_from(tlv_stream.to_bytes()) {
 871                         Ok(_) => panic!("expected error"),
 872                         Err(e) => {
 873                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::InvalidAmount));
 874                         },
 875                 }
 876         }
 877
 878         #[test]
 879         fn parses_refund_with_payer_id() {
 880                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 881                         .build().unwrap();
 882                 if let Err(e) = refund.to_string().parse::<Refund>() {
 883                         panic!("error parsing refund: {:?}", e);
 884                 }
 885
 886                 let mut tlv_stream = refund.as_tlv_stream();
 887                 tlv_stream.2.payer_id = None;
 888
 889                 match Refund::try_from(tlv_stream.to_bytes()) {
 890                         Ok(_) => panic!("expected error"),
 891                         Err(e) => {
 892                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::MissingPayerId));
 893                         },
 894                 }
 895         }
 896
 897         #[test]
 898         fn parses_refund_with_optional_fields() {
 899                 let past_expiry = Duration::from_secs(0);
 900                 let paths = vec![
 901                         BlindedPath {
 902                                 introduction_node_id: pubkey(40),
 903                                 blinding_point: pubkey(41),
 904                                 blinded_hops: vec![
 905                                         BlindedHop { blinded_node_id: pubkey(43), encrypted_payload: vec![0; 43] },
 906                                         BlindedHop { blinded_node_id: pubkey(44), encrypted_payload: vec![0; 44] },
 907                                 ],
 908                         },
 909                         BlindedPath {
 910                                 introduction_node_id: pubkey(40),
 911                                 blinding_point: pubkey(41),
 912                                 blinded_hops: vec![
 913                                         BlindedHop { blinded_node_id: pubkey(45), encrypted_payload: vec![0; 45] },
 914                                         BlindedHop { blinded_node_id: pubkey(46), encrypted_payload: vec![0; 46] },
 915                                 ],
 916                         },
 917                 ];
 918
 919                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 920                         .absolute_expiry(past_expiry)
 921                         .issuer("bar".into())
 922                         .path(paths[0].clone())
 923                         .path(paths[1].clone())
 924                         .chain(Network::Testnet)
 925                         .features_unchecked(InvoiceRequestFeatures::unknown())
 926                         .quantity(10)
 927                         .payer_note("baz".into())
 928                         .build()
 929                         .unwrap();
 930                 match refund.to_string().parse::<Refund>() {
 931                         Ok(refund) => {
 932                                 assert_eq!(refund.absolute_expiry(), Some(past_expiry));
 933                                 #[cfg(feature = "std")]
 934                                 assert!(refund.is_expired());
 935                                 assert_eq!(refund.paths(), &paths[..]);
 936                                 assert_eq!(refund.issuer(), Some(PrintableString("bar")));
 937                                 assert_eq!(refund.chain(), ChainHash::using_genesis_block(Network::Testnet));
 938                                 assert_eq!(refund.features(), &InvoiceRequestFeatures::unknown());
 939                                 assert_eq!(refund.quantity(), Some(10));
 940                                 assert_eq!(refund.payer_note(), Some(PrintableString("baz")));
 941                         },
 942                         Err(e) => panic!("error parsing refund: {:?}", e),
 943                 }
 944         }
 945
 946         #[test]
 947         fn fails_parsing_refund_with_unexpected_fields() {
 948                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], payer_pubkey(), 1000).unwrap()
 949                         .build().unwrap();
 950                 if let Err(e) = refund.to_string().parse::<Refund>() {
 951                         panic!("error parsing refund: {:?}", e);
 952                 }
 953
 954                 let metadata = vec![42; 32];
 955                 let mut tlv_stream = refund.as_tlv_stream();
 956                 tlv_stream.1.metadata = Some(&metadata);
 957
 958                 match Refund::try_from(tlv_stream.to_bytes()) {
 959                         Ok(_) => panic!("expected error"),
 960                         Err(e) => {
 961                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedMetadata));
 962                         },
 963                 }
 964
 965                 let chains = vec![ChainHash::using_genesis_block(Network::Testnet)];
 966                 let mut tlv_stream = refund.as_tlv_stream();
 967                 tlv_stream.1.chains = Some(&chains);
 968
 969                 match Refund::try_from(tlv_stream.to_bytes()) {
 970                         Ok(_) => panic!("expected error"),
 971                         Err(e) => {
 972                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedChain));
 973                         },
 974                 }
 975
 976                 let mut tlv_stream = refund.as_tlv_stream();
 977                 tlv_stream.1.currency = Some(&b"USD");
 978                 tlv_stream.1.amount = Some(1000);
 979
 980                 match Refund::try_from(tlv_stream.to_bytes()) {
 981                         Ok(_) => panic!("expected error"),
 982                         Err(e) => {
 983                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedAmount));
 984                         },
 985                 }
 986
 987                 let features = OfferFeatures::unknown();
 988                 let mut tlv_stream = refund.as_tlv_stream();
 989                 tlv_stream.1.features = Some(&features);
 990
 991                 match Refund::try_from(tlv_stream.to_bytes()) {
 992                         Ok(_) => panic!("expected error"),
 993                         Err(e) => {
 994                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedFeatures));
 995                         },
 996                 }
 997
 998                 let mut tlv_stream = refund.as_tlv_stream();
 999                 tlv_stream.1.quantity_max = Some(10);
1000
1001                 match Refund::try_from(tlv_stream.to_bytes()) {
1002                         Ok(_) => panic!("expected error"),
1003                         Err(e) => {
1004                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedQuantity));
1005                         },
1006                 }
1007
1008                 let node_id = payer_pubkey();
1009                 let mut tlv_stream = refund.as_tlv_stream();
1010                 tlv_stream.1.node_id = Some(&node_id);
1011
1012                 match Refund::try_from(tlv_stream.to_bytes()) {
1013                         Ok(_) => panic!("expected error"),
1014                         Err(e) => {
1015                                 assert_eq!(e, ParseError::InvalidSemantics(SemanticError::UnexpectedSigningPubkey));
1016                         },
1017                 }
1018         }
1019
1020         #[test]
1021         fn fails_parsing_refund_with_extra_tlv_records() {
1022                 let secp_ctx = Secp256k1::new();
1023                 let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
1024                 let refund = RefundBuilder::new("foo".into(), vec![1; 32], keys.public_key(), 1000).unwrap()
1025                         .build().unwrap();
1026
1027                 let mut encoded_refund = Vec::new();
1028                 refund.write(&mut encoded_refund).unwrap();
1029                 BigSize(1002).write(&mut encoded_refund).unwrap();
1030                 BigSize(32).write(&mut encoded_refund).unwrap();
1031                 [42u8; 32].write(&mut encoded_refund).unwrap();
1032
1033                 match Refund::try_from(encoded_refund) {
1034                         Ok(_) => panic!("expected error"),
1035                         Err(e) => assert_eq!(e, ParseError::Decode(DecodeError::InvalidValue)),
1036                 }
1037         }
1038 }