_ Git - rust-lightning/blob - lightning/src/offers/invoice.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 `invoice` messages.
  11
  12 use bitcoin::blockdata::constants::ChainHash;
  13 use bitcoin::hash_types::{WPubkeyHash, WScriptHash};
  14 use bitcoin::hashes::Hash;
  15 use bitcoin::network::constants::Network;
  16 use bitcoin::secp256k1::{Message, PublicKey};
  17 use bitcoin::secp256k1::schnorr::Signature;
  18 use bitcoin::util::address::{Address, Payload, WitnessVersion};
  19 use bitcoin::util::schnorr::TweakedPublicKey;
  20 use core::convert::TryFrom;
  21 use core::time::Duration;
  22 use crate::io;
  23 use crate::ln::PaymentHash;
  24 use crate::ln::features::{BlindedHopFeatures, Bolt12InvoiceFeatures};
  25 use crate::ln::msgs::DecodeError;
  26 use crate::offers::invoice_request::{InvoiceRequest, InvoiceRequestContents, InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef};
  27 use crate::offers::merkle::{SignError, SignatureTlvStream, SignatureTlvStreamRef, WithoutSignatures, self};
  28 use crate::offers::offer::{Amount, OfferTlvStream, OfferTlvStreamRef};
  29 use crate::offers::parse::{ParseError, ParsedMessage, SemanticError};
  30 use crate::offers::payer::{PayerTlvStream, PayerTlvStreamRef};
  31 use crate::offers::refund::RefundContents;
  32 use crate::onion_message::BlindedPath;
  33 use crate::util::ser::{HighZeroBytesDroppedBigSize, Iterable, SeekReadable, WithoutLength, Writeable, Writer};
  34
  35 use crate::prelude::*;
  36
  37 #[cfg(feature = "std")]
  38 use std::time::SystemTime;
  39
  40 const DEFAULT_RELATIVE_EXPIRY: Duration = Duration::from_secs(7200);
  41
  42 const SIGNATURE_TAG: &'static str = concat!("lightning", "invoice", "signature");
  43
  44 /// Builds an [`Invoice`] from either:
  45 /// - an [`InvoiceRequest`] for the "offer to be paid" flow or
  46 /// - a [`Refund`] for the "offer for money" flow.
  47 ///
  48 /// See [module-level documentation] for usage.
  49 ///
  50 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
  51 /// [`Refund`]: crate::offers::refund::Refund
  52 /// [module-level documentation]: self
  53 pub struct InvoiceBuilder<'a> {
  54         invreq_bytes: &'a Vec<u8>,
  55         invoice: InvoiceContents,
  56 }
  57
  58 impl<'a> InvoiceBuilder<'a> {
  59         pub(super) fn for_offer(
  60                 invoice_request: &'a InvoiceRequest, payment_paths: Vec<(BlindedPath, BlindedPayInfo)>,
  61                 created_at: Duration, payment_hash: PaymentHash
  62         ) -> Result<Self, SemanticError> {
  63                 if payment_paths.is_empty() {
  64                         return Err(SemanticError::MissingPaths);
  65                 }
  66
  67                 let amount_msats = match invoice_request.amount_msats() {
  68                         Some(amount_msats) => amount_msats,
  69                         None => match invoice_request.contents.offer.amount() {
  70                                 Some(Amount::Bitcoin { amount_msats }) => {
  71                                         amount_msats * invoice_request.quantity().unwrap_or(1)
  72                                 },
  73                                 Some(Amount::Currency { .. }) => return Err(SemanticError::UnsupportedCurrency),
  74                                 None => return Err(SemanticError::MissingAmount),
  75                         },
  76                 };
  77
  78                 Ok(Self {
  79                         invreq_bytes: &invoice_request.bytes,
  80                         invoice: InvoiceContents::ForOffer {
  81                                 invoice_request: invoice_request.contents.clone(),
  82                                 fields: InvoiceFields {
  83                                         payment_paths, created_at, relative_expiry: None, payment_hash, amount_msats,
  84                                         fallbacks: None, features: Bolt12InvoiceFeatures::empty(),
  85                                         signing_pubkey: invoice_request.contents.offer.signing_pubkey(),
  86                                 },
  87                         },
  88                 })
  89         }
  90
  91         /// Sets the [`Invoice::relative_expiry`] as seconds since [`Invoice::created_at`]. Any expiry
  92         /// that has already passed is valid and can be checked for using [`Invoice::is_expired`].
  93         ///
  94         /// Successive calls to this method will override the previous setting.
  95         pub fn relative_expiry(mut self, relative_expiry_secs: u32) -> Self {
  96                 let relative_expiry = Duration::from_secs(relative_expiry_secs as u64);
  97                 self.invoice.fields_mut().relative_expiry = Some(relative_expiry);
  98                 self
  99         }
 100
 101         /// Adds a P2WSH address to [`Invoice::fallbacks`].
 102         ///
 103         /// Successive calls to this method will add another address. Caller is responsible for not
 104         /// adding duplicate addresses and only calling if capable of receiving to P2WSH addresses.
 105         pub fn fallback_v0_p2wsh(mut self, script_hash: &WScriptHash) -> Self {
 106                 let address = FallbackAddress {
 107                         version: WitnessVersion::V0.to_num(),
 108                         program: Vec::from(&script_hash.into_inner()[..]),
 109                 };
 110                 self.invoice.fields_mut().fallbacks.get_or_insert_with(Vec::new).push(address);
 111                 self
 112         }
 113
 114         /// Adds a P2WPKH address to [`Invoice::fallbacks`].
 115         ///
 116         /// Successive calls to this method will add another address. Caller is responsible for not
 117         /// adding duplicate addresses and only calling if capable of receiving to P2WPKH addresses.
 118         pub fn fallback_v0_p2wpkh(mut self, pubkey_hash: &WPubkeyHash) -> Self {
 119                 let address = FallbackAddress {
 120                         version: WitnessVersion::V0.to_num(),
 121                         program: Vec::from(&pubkey_hash.into_inner()[..]),
 122                 };
 123                 self.invoice.fields_mut().fallbacks.get_or_insert_with(Vec::new).push(address);
 124                 self
 125         }
 126
 127         /// Adds a P2TR address to [`Invoice::fallbacks`].
 128         ///
 129         /// Successive calls to this method will add another address. Caller is responsible for not
 130         /// adding duplicate addresses and only calling if capable of receiving to P2TR addresses.
 131         pub fn fallback_v1_p2tr_tweaked(mut self, output_key: &TweakedPublicKey) -> Self {
 132                 let address = FallbackAddress {
 133                         version: WitnessVersion::V1.to_num(),
 134                         program: Vec::from(&output_key.serialize()[..]),
 135                 };
 136                 self.invoice.fields_mut().fallbacks.get_or_insert_with(Vec::new).push(address);
 137                 self
 138         }
 139
 140         /// Sets [`Invoice::features`] to indicate MPP may be used. Otherwise, MPP is disallowed.
 141         pub fn allow_mpp(mut self) -> Self {
 142                 self.invoice.fields_mut().features.set_basic_mpp_optional();
 143                 self
 144         }
 145
 146         /// Builds an unsigned [`Invoice`] after checking for valid semantics. It can be signed by
 147         /// [`UnsignedInvoice::sign`].
 148         pub fn build(self) -> Result<UnsignedInvoice<'a>, SemanticError> {
 149                 #[cfg(feature = "std")] {
 150                         if self.invoice.is_offer_or_refund_expired() {
 151                                 return Err(SemanticError::AlreadyExpired);
 152                         }
 153                 }
 154
 155                 let InvoiceBuilder { invreq_bytes, invoice } = self;
 156                 Ok(UnsignedInvoice { invreq_bytes, invoice })
 157         }
 158 }
 159
 160 /// A semantically valid [`Invoice`] that hasn't been signed.
 161 pub struct UnsignedInvoice<'a> {
 162         invreq_bytes: &'a Vec<u8>,
 163         invoice: InvoiceContents,
 164 }
 165
 166 impl<'a> UnsignedInvoice<'a> {
 167         /// Signs the invoice using the given function.
 168         pub fn sign<F, E>(self, sign: F) -> Result<Invoice, SignError<E>>
 169         where
 170                 F: FnOnce(&Message) -> Result<Signature, E>
 171         {
 172                 // Use the invoice_request bytes instead of the invoice_request TLV stream as the latter may
 173                 // have contained unknown TLV records, which are not stored in `InvoiceRequestContents` or
 174                 // `RefundContents`.
 175                 let (_, _, _, invoice_tlv_stream) = self.invoice.as_tlv_stream();
 176                 let invoice_request_bytes = WithoutSignatures(self.invreq_bytes);
 177                 let unsigned_tlv_stream = (invoice_request_bytes, invoice_tlv_stream);
 178
 179                 let mut bytes = Vec::new();
 180                 unsigned_tlv_stream.write(&mut bytes).unwrap();
 181
 182                 let pubkey = self.invoice.fields().signing_pubkey;
 183                 let signature = merkle::sign_message(sign, SIGNATURE_TAG, &bytes, pubkey)?;
 184
 185                 // Append the signature TLV record to the bytes.
 186                 let signature_tlv_stream = SignatureTlvStreamRef {
 187                         signature: Some(&signature),
 188                 };
 189                 signature_tlv_stream.write(&mut bytes).unwrap();
 190
 191                 Ok(Invoice {
 192                         bytes,
 193                         contents: self.invoice,
 194                         signature,
 195                 })
 196         }
 197 }
 198
 199 /// An `Invoice` is a payment request, typically corresponding to an [`Offer`] or a [`Refund`].
 200 ///
 201 /// An invoice may be sent in response to an [`InvoiceRequest`] in the case of an offer or sent
 202 /// directly after scanning a refund. It includes all the information needed to pay a recipient.
 203 ///
 204 /// [`Offer`]: crate::offers::offer::Offer
 205 /// [`Refund`]: crate::offers::refund::Refund
 206 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 207 pub struct Invoice {
 208         bytes: Vec<u8>,
 209         contents: InvoiceContents,
 210         signature: Signature,
 211 }
 212
 213 /// The contents of an [`Invoice`] for responding to either an [`Offer`] or a [`Refund`].
 214 ///
 215 /// [`Offer`]: crate::offers::offer::Offer
 216 /// [`Refund`]: crate::offers::refund::Refund
 217 enum InvoiceContents {
 218         /// Contents for an [`Invoice`] corresponding to an [`Offer`].
 219         ///
 220         /// [`Offer`]: crate::offers::offer::Offer
 221         ForOffer {
 222                 invoice_request: InvoiceRequestContents,
 223                 fields: InvoiceFields,
 224         },
 225         /// Contents for an [`Invoice`] corresponding to a [`Refund`].
 226         ///
 227         /// [`Refund`]: crate::offers::refund::Refund
 228         ForRefund {
 229                 refund: RefundContents,
 230                 fields: InvoiceFields,
 231         },
 232 }
 233
 234 /// Invoice-specific fields for an `invoice` message.
 235 struct InvoiceFields {
 236         payment_paths: Vec<(BlindedPath, BlindedPayInfo)>,
 237         created_at: Duration,
 238         relative_expiry: Option<Duration>,
 239         payment_hash: PaymentHash,
 240         amount_msats: u64,
 241         fallbacks: Option<Vec<FallbackAddress>>,
 242         features: Bolt12InvoiceFeatures,
 243         signing_pubkey: PublicKey,
 244 }
 245
 246 impl Invoice {
 247         /// Paths to the recipient originating from publicly reachable nodes, including information
 248         /// needed for routing payments across them. Blinded paths provide recipient privacy by
 249         /// obfuscating its node id.
 250         pub fn payment_paths(&self) -> &[(BlindedPath, BlindedPayInfo)] {
 251                 &self.contents.fields().payment_paths[..]
 252         }
 253
 254         /// Duration since the Unix epoch when the invoice was created.
 255         pub fn created_at(&self) -> Duration {
 256                 self.contents.fields().created_at
 257         }
 258
 259         /// Duration since [`Invoice::created_at`] when the invoice has expired and therefore should no
 260         /// longer be paid.
 261         pub fn relative_expiry(&self) -> Duration {
 262                 self.contents.fields().relative_expiry.unwrap_or(DEFAULT_RELATIVE_EXPIRY)
 263         }
 264
 265         /// Whether the invoice has expired.
 266         #[cfg(feature = "std")]
 267         pub fn is_expired(&self) -> bool {
 268                 let absolute_expiry = self.created_at().checked_add(self.relative_expiry());
 269                 match absolute_expiry {
 270                         Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
 271                                 Ok(elapsed) => elapsed > seconds_from_epoch,
 272                                 Err(_) => false,
 273                         },
 274                         None => false,
 275                 }
 276         }
 277
 278         /// SHA256 hash of the payment preimage that will be given in return for paying the invoice.
 279         pub fn payment_hash(&self) -> PaymentHash {
 280                 self.contents.fields().payment_hash
 281         }
 282
 283         /// The minimum amount required for a successful payment of the invoice.
 284         pub fn amount_msats(&self) -> u64 {
 285                 self.contents.fields().amount_msats
 286         }
 287
 288         /// Fallback addresses for paying the invoice on-chain, in order of most-preferred to
 289         /// least-preferred.
 290         pub fn fallbacks(&self) -> Vec<Address> {
 291                 let network = match self.network() {
 292                         None => return Vec::new(),
 293                         Some(network) => network,
 294                 };
 295
 296                 let to_valid_address = |address: &FallbackAddress| {
 297                         let version = match WitnessVersion::try_from(address.version) {
 298                                 Ok(version) => version,
 299                                 Err(_) => return None,
 300                         };
 301
 302                         let program = &address.program;
 303                         if program.len() < 2 || program.len() > 40 {
 304                                 return None;
 305                         }
 306
 307                         let address = Address {
 308                                 payload: Payload::WitnessProgram {
 309                                         version,
 310                                         program: address.program.clone(),
 311                                 },
 312                                 network,
 313                         };
 314
 315                         if !address.is_standard() && version == WitnessVersion::V0 {
 316                                 return None;
 317                         }
 318
 319                         Some(address)
 320                 };
 321
 322                 self.contents.fields().fallbacks
 323                         .as_ref()
 324                         .map(|fallbacks| fallbacks.iter().filter_map(to_valid_address).collect())
 325                         .unwrap_or_else(Vec::new)
 326         }
 327
 328         fn network(&self) -> Option<Network> {
 329                 let chain = self.contents.chain();
 330                 if chain == ChainHash::using_genesis_block(Network::Bitcoin) {
 331                         Some(Network::Bitcoin)
 332                 } else if chain == ChainHash::using_genesis_block(Network::Testnet) {
 333                         Some(Network::Testnet)
 334                 } else if chain == ChainHash::using_genesis_block(Network::Signet) {
 335                         Some(Network::Signet)
 336                 } else if chain == ChainHash::using_genesis_block(Network::Regtest) {
 337                         Some(Network::Regtest)
 338                 } else {
 339                         None
 340                 }
 341         }
 342
 343         /// Features pertaining to paying an invoice.
 344         pub fn features(&self) -> &Bolt12InvoiceFeatures {
 345                 &self.contents.fields().features
 346         }
 347
 348         /// The public key used to sign invoices.
 349         pub fn signing_pubkey(&self) -> PublicKey {
 350                 self.contents.fields().signing_pubkey
 351         }
 352
 353         /// Signature of the invoice using [`Invoice::signing_pubkey`].
 354         pub fn signature(&self) -> Signature {
 355                 self.signature
 356         }
 357 }
 358
 359 impl InvoiceContents {
 360         /// Whether the original offer or refund has expired.
 361         #[cfg(feature = "std")]
 362         fn is_offer_or_refund_expired(&self) -> bool {
 363                 match self {
 364                         InvoiceContents::ForOffer { invoice_request, .. } => invoice_request.offer.is_expired(),
 365                         InvoiceContents::ForRefund { refund, .. } => refund.is_expired(),
 366                 }
 367         }
 368
 369         fn chain(&self) -> ChainHash {
 370                 match self {
 371                         InvoiceContents::ForOffer { invoice_request, .. } => invoice_request.chain(),
 372                         InvoiceContents::ForRefund { refund, .. } => refund.chain(),
 373                 }
 374         }
 375
 376         fn fields(&self) -> &InvoiceFields {
 377                 match self {
 378                         InvoiceContents::ForOffer { fields, .. } => fields,
 379                         InvoiceContents::ForRefund { fields, .. } => fields,
 380                 }
 381         }
 382
 383         fn fields_mut(&mut self) -> &mut InvoiceFields {
 384                 match self {
 385                         InvoiceContents::ForOffer { fields, .. } => fields,
 386                         InvoiceContents::ForRefund { fields, .. } => fields,
 387                 }
 388         }
 389
 390         fn as_tlv_stream(&self) -> PartialInvoiceTlvStreamRef {
 391                 let (payer, offer, invoice_request) = match self {
 392                         InvoiceContents::ForOffer { invoice_request, .. } => invoice_request.as_tlv_stream(),
 393                         InvoiceContents::ForRefund { refund, .. } => refund.as_tlv_stream(),
 394                 };
 395                 let invoice = self.fields().as_tlv_stream();
 396
 397                 (payer, offer, invoice_request, invoice)
 398         }
 399 }
 400
 401 impl InvoiceFields {
 402         fn as_tlv_stream(&self) -> InvoiceTlvStreamRef {
 403                 let features = {
 404                         if self.features == Bolt12InvoiceFeatures::empty() { None }
 405                         else { Some(&self.features) }
 406                 };
 407
 408                 InvoiceTlvStreamRef {
 409                         paths: Some(Iterable(self.payment_paths.iter().map(|(path, _)| path))),
 410                         blindedpay: Some(Iterable(self.payment_paths.iter().map(|(_, payinfo)| payinfo))),
 411                         created_at: Some(self.created_at.as_secs()),
 412                         relative_expiry: self.relative_expiry.map(|duration| duration.as_secs() as u32),
 413                         payment_hash: Some(&self.payment_hash),
 414                         amount: Some(self.amount_msats),
 415                         fallbacks: self.fallbacks.as_ref(),
 416                         features,
 417                         node_id: Some(&self.signing_pubkey),
 418                 }
 419         }
 420 }
 421
 422 impl Writeable for Invoice {
 423         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 424                 WithoutLength(&self.bytes).write(writer)
 425         }
 426 }
 427
 428 impl TryFrom<Vec<u8>> for Invoice {
 429         type Error = ParseError;
 430
 431         fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
 432                 let parsed_invoice = ParsedMessage::<FullInvoiceTlvStream>::try_from(bytes)?;
 433                 Invoice::try_from(parsed_invoice)
 434         }
 435 }
 436
 437 tlv_stream!(InvoiceTlvStream, InvoiceTlvStreamRef, 160..240, {
 438         (160, paths: (Vec<BlindedPath>, WithoutLength, Iterable<'a, BlindedPathIter<'a>, BlindedPath>)),
 439         (162, blindedpay: (Vec<BlindedPayInfo>, WithoutLength, Iterable<'a, BlindedPayInfoIter<'a>, BlindedPayInfo>)),
 440         (164, created_at: (u64, HighZeroBytesDroppedBigSize)),
 441         (166, relative_expiry: (u32, HighZeroBytesDroppedBigSize)),
 442         (168, payment_hash: PaymentHash),
 443         (170, amount: (u64, HighZeroBytesDroppedBigSize)),
 444         (172, fallbacks: (Vec<FallbackAddress>, WithoutLength)),
 445         (174, features: (Bolt12InvoiceFeatures, WithoutLength)),
 446         (176, node_id: PublicKey),
 447 });
 448
 449 type BlindedPathIter<'a> = core::iter::Map<
 450         core::slice::Iter<'a, (BlindedPath, BlindedPayInfo)>,
 451         for<'r> fn(&'r (BlindedPath, BlindedPayInfo)) -> &'r BlindedPath,
 452 >;
 453
 454 type BlindedPayInfoIter<'a> = core::iter::Map<
 455         core::slice::Iter<'a, (BlindedPath, BlindedPayInfo)>,
 456         for<'r> fn(&'r (BlindedPath, BlindedPayInfo)) -> &'r BlindedPayInfo,
 457 >;
 458
 459 /// Information needed to route a payment across a [`BlindedPath`].
 460 #[derive(Debug, PartialEq)]
 461 pub struct BlindedPayInfo {
 462         fee_base_msat: u32,
 463         fee_proportional_millionths: u32,
 464         cltv_expiry_delta: u16,
 465         htlc_minimum_msat: u64,
 466         htlc_maximum_msat: u64,
 467         features: BlindedHopFeatures,
 468 }
 469
 470 impl_writeable!(BlindedPayInfo, {
 471         fee_base_msat,
 472         fee_proportional_millionths,
 473         cltv_expiry_delta,
 474         htlc_minimum_msat,
 475         htlc_maximum_msat,
 476         features
 477 });
 478
 479 /// Wire representation for an on-chain fallback address.
 480 #[derive(Debug, PartialEq)]
 481 pub(super) struct FallbackAddress {
 482         version: u8,
 483         program: Vec<u8>,
 484 }
 485
 486 impl_writeable!(FallbackAddress, { version, program });
 487
 488 type FullInvoiceTlvStream =
 489         (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream, InvoiceTlvStream, SignatureTlvStream);
 490
 491 impl SeekReadable for FullInvoiceTlvStream {
 492         fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
 493                 let payer = SeekReadable::read(r)?;
 494                 let offer = SeekReadable::read(r)?;
 495                 let invoice_request = SeekReadable::read(r)?;
 496                 let invoice = SeekReadable::read(r)?;
 497                 let signature = SeekReadable::read(r)?;
 498
 499                 Ok((payer, offer, invoice_request, invoice, signature))
 500         }
 501 }
 502
 503 type PartialInvoiceTlvStream =
 504         (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream, InvoiceTlvStream);
 505
 506 type PartialInvoiceTlvStreamRef<'a> = (
 507         PayerTlvStreamRef<'a>,
 508         OfferTlvStreamRef<'a>,
 509         InvoiceRequestTlvStreamRef<'a>,
 510         InvoiceTlvStreamRef<'a>,
 511 );
 512
 513 impl TryFrom<ParsedMessage<FullInvoiceTlvStream>> for Invoice {
 514         type Error = ParseError;
 515
 516         fn try_from(invoice: ParsedMessage<FullInvoiceTlvStream>) -> Result<Self, Self::Error> {
 517                 let ParsedMessage { bytes, tlv_stream } = invoice;
 518                 let (
 519                         payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream, invoice_tlv_stream,
 520                         SignatureTlvStream { signature },
 521                 ) = tlv_stream;
 522                 let contents = InvoiceContents::try_from(
 523                         (payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream, invoice_tlv_stream)
 524                 )?;
 525
 526                 let signature = match signature {
 527                         None => return Err(ParseError::InvalidSemantics(SemanticError::MissingSignature)),
 528                         Some(signature) => signature,
 529                 };
 530                 let pubkey = contents.fields().signing_pubkey;
 531                 merkle::verify_signature(&signature, SIGNATURE_TAG, &bytes, pubkey)?;
 532
 533                 Ok(Invoice { bytes, contents, signature })
 534         }
 535 }
 536
 537 impl TryFrom<PartialInvoiceTlvStream> for InvoiceContents {
 538         type Error = SemanticError;
 539
 540         fn try_from(tlv_stream: PartialInvoiceTlvStream) -> Result<Self, Self::Error> {
 541                 let (
 542                         payer_tlv_stream,
 543                         offer_tlv_stream,
 544                         invoice_request_tlv_stream,
 545                         InvoiceTlvStream {
 546                                 paths, blindedpay, created_at, relative_expiry, payment_hash, amount, fallbacks,
 547                                 features, node_id,
 548                         },
 549                 ) = tlv_stream;
 550
 551                 let payment_paths = match (paths, blindedpay) {
 552                         (None, _) => return Err(SemanticError::MissingPaths),
 553                         (_, None) => return Err(SemanticError::InvalidPayInfo),
 554                         (Some(paths), _) if paths.is_empty() => return Err(SemanticError::MissingPaths),
 555                         (Some(paths), Some(blindedpay)) if paths.len() != blindedpay.len() => {
 556                                 return Err(SemanticError::InvalidPayInfo);
 557                         },
 558                         (Some(paths), Some(blindedpay)) => {
 559                                 paths.into_iter().zip(blindedpay.into_iter()).collect::<Vec<_>>()
 560                         },
 561                 };
 562
 563                 let created_at = match created_at {
 564                         None => return Err(SemanticError::MissingCreationTime),
 565                         Some(timestamp) => Duration::from_secs(timestamp),
 566                 };
 567
 568                 let relative_expiry = relative_expiry
 569                         .map(Into::<u64>::into)
 570                         .map(Duration::from_secs);
 571
 572                 let payment_hash = match payment_hash {
 573                         None => return Err(SemanticError::MissingPaymentHash),
 574                         Some(payment_hash) => payment_hash,
 575                 };
 576
 577                 let amount_msats = match amount {
 578                         None => return Err(SemanticError::MissingAmount),
 579                         Some(amount) => amount,
 580                 };
 581
 582                 let features = features.unwrap_or_else(Bolt12InvoiceFeatures::empty);
 583
 584                 let signing_pubkey = match node_id {
 585                         None => return Err(SemanticError::MissingSigningPubkey),
 586                         Some(node_id) => node_id,
 587                 };
 588
 589                 let fields = InvoiceFields {
 590                         payment_paths, created_at, relative_expiry, payment_hash, amount_msats, fallbacks,
 591                         features, signing_pubkey,
 592                 };
 593
 594                 match offer_tlv_stream.node_id {
 595                         Some(expected_signing_pubkey) => {
 596                                 if fields.signing_pubkey != expected_signing_pubkey {
 597                                         return Err(SemanticError::InvalidSigningPubkey);
 598                                 }
 599
 600                                 let invoice_request = InvoiceRequestContents::try_from(
 601                                         (payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream)
 602                                 )?;
 603                                 Ok(InvoiceContents::ForOffer { invoice_request, fields })
 604                         },
 605                         None => {
 606                                 let refund = RefundContents::try_from(
 607                                         (payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream)
 608                                 )?;
 609                                 Ok(InvoiceContents::ForRefund { refund, fields })
 610                         },
 611                 }
 612         }
 613 }