--- /dev/null
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+//! Data structures and encoding for refunds.
+//!
+//! A [`Refund`] is an "offer for money" and is typically constructed by a merchant and presented
+//! directly to the customer. The recipient responds with an `Invoice` to be paid.
+//!
+//! This is an [`InvoiceRequest`] produced *not* in response to an [`Offer`].
+//!
+//! [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
+//! [`Offer`]: crate::offers::offer::Offer
+
+use bitcoin::blockdata::constants::ChainHash;
+use bitcoin::network::constants::Network;
+use bitcoin::secp256k1::PublicKey;
+use core::convert::TryFrom;
+use core::time::Duration;
+use crate::io;
+use crate::ln::features::InvoiceRequestFeatures;
+use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
+use crate::offers::invoice_request::InvoiceRequestTlvStream;
+use crate::offers::offer::OfferTlvStream;
+use crate::offers::parse::{ParseError, ParsedMessage, SemanticError};
+use crate::offers::payer::{PayerContents, PayerTlvStream};
+use crate::onion_message::BlindedPath;
+use crate::util::ser::SeekReadable;
+use crate::util::string::PrintableString;
+
+use crate::prelude::*;
+
+#[cfg(feature = "std")]
+use std::time::SystemTime;
+
+/// A `Refund` is a request to send an `Invoice` without a preceding [`Offer`].
+///
+/// Typically, after an invoice is paid, the recipient may publish a refund allowing the sender to
+/// recoup their funds. A refund may be used more generally as an "offer for money", such as with a
+/// bitcoin ATM.
+///
+/// [`Offer`]: crate::offers::offer::Offer
+#[derive(Clone, Debug)]
+pub struct Refund {
+ bytes: Vec<u8>,
+ contents: RefundContents,
+}
+
+/// The contents of a [`Refund`], which may be shared with an `Invoice`.
+#[derive(Clone, Debug)]
+struct RefundContents {
+ payer: PayerContents,
+ // offer fields
+ metadata: Option<Vec<u8>>,
+ description: String,
+ absolute_expiry: Option<Duration>,
+ issuer: Option<String>,
+ paths: Option<Vec<BlindedPath>>,
+ // invoice_request fields
+ chain: Option<ChainHash>,
+ amount_msats: u64,
+ features: InvoiceRequestFeatures,
+ payer_id: PublicKey,
+ payer_note: Option<String>,
+}
+
+impl Refund {
+ /// A complete description of the purpose of the refund. Intended to be displayed to the user
+ /// but with the caveat that it has not been verified in any way.
+ pub fn description(&self) -> PrintableString {
+ PrintableString(&self.contents.description)
+ }
+
+ /// Duration since the Unix epoch when an invoice should no longer be sent.
+ ///
+ /// If `None`, the refund does not expire.
+ pub fn absolute_expiry(&self) -> Option<Duration> {
+ self.contents.absolute_expiry
+ }
+
+ /// Whether the refund has expired.
+ #[cfg(feature = "std")]
+ pub fn is_expired(&self) -> bool {
+ match self.absolute_expiry() {
+ Some(seconds_from_epoch) => match SystemTime::UNIX_EPOCH.elapsed() {
+ Ok(elapsed) => elapsed > seconds_from_epoch,
+ Err(_) => false,
+ },
+ None => false,
+ }
+ }
+
+ /// The issuer of the refund, possibly beginning with `user@domain` or `domain`. Intended to be
+ /// displayed to the user but with the caveat that it has not been verified in any way.
+ pub fn issuer(&self) -> Option<PrintableString> {
+ self.contents.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
+ }
+
+ /// Paths to the sender originating from publicly reachable nodes. Blinded paths provide sender
+ /// privacy by obfuscating its node id.
+ pub fn paths(&self) -> &[BlindedPath] {
+ self.contents.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
+ }
+
+ /// An unpredictable series of bytes, typically containing information about the derivation of
+ /// [`payer_id`].
+ ///
+ /// [`payer_id`]: Self::payer_id
+ pub fn metadata(&self) -> &[u8] {
+ &self.contents.payer.0
+ }
+
+ /// A chain that the refund is valid for.
+ pub fn chain(&self) -> ChainHash {
+ self.contents.chain.unwrap_or_else(|| ChainHash::using_genesis_block(Network::Bitcoin))
+ }
+
+ /// The amount to refund in msats (i.e., the minimum lightning-payable unit for [`chain`]).
+ ///
+ /// [`chain`]: Self::chain
+ pub fn amount_msats(&self) -> u64 {
+ self.contents.amount_msats
+ }
+
+ /// Features pertaining to requesting an invoice.
+ pub fn features(&self) -> &InvoiceRequestFeatures {
+ &self.contents.features
+ }
+
+ /// A possibly transient pubkey used to sign the refund.
+ pub fn payer_id(&self) -> PublicKey {
+ self.contents.payer_id
+ }
+
+ /// Payer provided note to include in the invoice.
+ pub fn payer_note(&self) -> Option<PrintableString> {
+ self.contents.payer_note.as_ref().map(|payer_note| PrintableString(payer_note.as_str()))
+ }
+}
+
+type RefundTlvStream = (PayerTlvStream, OfferTlvStream, InvoiceRequestTlvStream);
+
+impl SeekReadable for RefundTlvStream {
+ fn read<R: io::Read + io::Seek>(r: &mut R) -> Result<Self, DecodeError> {
+ let payer = SeekReadable::read(r)?;
+ let offer = SeekReadable::read(r)?;
+ let invoice_request = SeekReadable::read(r)?;
+
+ Ok((payer, offer, invoice_request))
+ }
+}
+
+impl TryFrom<Vec<u8>> for Refund {
+ type Error = ParseError;
+
+ fn try_from(bytes: Vec<u8>) -> Result<Self, Self::Error> {
+ let refund = ParsedMessage::<RefundTlvStream>::try_from(bytes)?;
+ let ParsedMessage { bytes, tlv_stream } = refund;
+ let contents = RefundContents::try_from(tlv_stream)?;
+
+ Ok(Refund { bytes, contents })
+ }
+}
+
+impl TryFrom<RefundTlvStream> for RefundContents {
+ type Error = SemanticError;
+
+ fn try_from(tlv_stream: RefundTlvStream) -> Result<Self, Self::Error> {
+ let (
+ PayerTlvStream { metadata: payer_metadata },
+ OfferTlvStream {
+ chains, metadata, currency, amount: offer_amount, description,
+ features: offer_features, absolute_expiry, paths, issuer, quantity_max, node_id,
+ },
+ InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
+ ) = tlv_stream;
+
+ let payer = match payer_metadata {
+ None => return Err(SemanticError::MissingPayerMetadata),
+ Some(metadata) => PayerContents(metadata),
+ };
+
+ if chains.is_some() {
+ return Err(SemanticError::UnexpectedChain);
+ }
+
+ if currency.is_some() || offer_amount.is_some() {
+ return Err(SemanticError::UnexpectedAmount);
+ }
+
+ let description = match description {
+ None => return Err(SemanticError::MissingDescription),
+ Some(description) => description,
+ };
+
+ if offer_features.is_some() {
+ return Err(SemanticError::UnexpectedFeatures);
+ }
+
+ let absolute_expiry = absolute_expiry.map(Duration::from_secs);
+
+ if quantity_max.is_some() {
+ return Err(SemanticError::UnexpectedQuantity);
+ }
+
+ if node_id.is_some() {
+ return Err(SemanticError::UnexpectedSigningPubkey);
+ }
+
+ let amount_msats = match amount {
+ None => return Err(SemanticError::MissingAmount),
+ Some(amount_msats) if amount_msats > MAX_VALUE_MSAT => {
+ return Err(SemanticError::InvalidAmount);
+ },
+ Some(amount_msats) => amount_msats,
+ };
+
+ let features = features.unwrap_or_else(InvoiceRequestFeatures::empty);
+
+ // TODO: Check why this isn't in the spec.
+ if quantity.is_some() {
+ return Err(SemanticError::UnexpectedQuantity);
+ }
+
+ let payer_id = match payer_id {
+ None => return Err(SemanticError::MissingPayerId),
+ Some(payer_id) => payer_id,
+ };
+
+ // TODO: Should metadata be included?
+ Ok(RefundContents {
+ payer, metadata, description, absolute_expiry, issuer, paths, chain, amount_msats,
+ features, payer_id, payer_note,
+ })
+ }
+}
projects / rust-lightning / commitdiff