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offer.rs
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// 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 `offer` messages.
//!
//! An [`Offer`] represents an "offer to be paid." It is typically constructed by a merchant and
//! published as a QR code to be scanned by a customer. The customer uses the offer to request an
//! invoice from the merchant to be paid.
//!
//! # Example
//!
//! ```
//! extern crate bitcoin;
//! extern crate core;
//! extern crate lightning;
//!
//! use core::convert::TryFrom;
//! use core::num::NonZeroU64;
//! use core::time::Duration;
//!
//! use bitcoin::secp256k1::{Keypair, PublicKey, Secp256k1, SecretKey};
//! use lightning::offers::offer::{Offer, OfferBuilder, Quantity};
//! use lightning::offers::parse::Bolt12ParseError;
//! use lightning::util::ser::{Readable, Writeable};
//!
//! # use lightning::blinded_path::message::BlindedMessagePath;
//! # #[cfg(feature = "std")]
//! # use std::time::SystemTime;
//! #
//! # fn create_blinded_path() -> BlindedMessagePath { unimplemented!() }
//! # fn create_another_blinded_path() -> BlindedMessagePath { unimplemented!() }
//! #
//! # #[cfg(feature = "std")]
//! # fn build() -> Result<(), Bolt12ParseError> {
//! let secp_ctx = Secp256k1::new();
//! let keys = Keypair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
//! let pubkey = PublicKey::from(keys);
//!
//! let expiration = SystemTime::now() + Duration::from_secs(24 * 60 * 60);
//! let offer = OfferBuilder::new(pubkey)
//! .description("coffee, large".to_string())
//! .amount_msats(20_000)
//! .supported_quantity(Quantity::Unbounded)
//! .absolute_expiry(expiration.duration_since(SystemTime::UNIX_EPOCH).unwrap())
//! .issuer("Foo Bar".to_string())
//! .path(create_blinded_path())
//! .path(create_another_blinded_path())
//! .build()?;
//!
//! // Encode as a bech32 string for use in a QR code.
//! let encoded_offer = offer.to_string();
//!
//! // Parse from a bech32 string after scanning from a QR code.
//! let offer = encoded_offer.parse::<Offer>()?;
//!
//! // Encode offer as raw bytes.
//! let mut bytes = Vec::new();
//! offer.write(&mut bytes).unwrap();
//!
//! // Decode raw bytes into an offer.
//! let offer = Offer::try_from(bytes)?;
//! # Ok(())
//! # }
//! ```
//!
//! # Note
//!
//! If constructing an [`Offer`] for use with a [`ChannelManager`], use
//! [`ChannelManager::create_offer_builder`] instead of [`OfferBuilder::new`].
//!
//! [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
//! [`ChannelManager::create_offer_builder`]: crate::ln::channelmanager::ChannelManager::create_offer_builder
use crate::blinded_path::message::BlindedMessagePath;
use crate::io;
use crate::ln::channelmanager::PaymentId;
use crate::ln::inbound_payment::{ExpandedKey, IV_LEN};
use crate::ln::msgs::{DecodeError, MAX_VALUE_MSAT};
use crate::offers::merkle::{TaggedHash, TlvRecord, TlvStream};
use crate::offers::nonce::Nonce;
use crate::offers::parse::{Bech32Encode, Bolt12ParseError, Bolt12SemanticError, ParsedMessage};
use crate::offers::signer::{self, Metadata, MetadataMaterial};
use crate::types::features::OfferFeatures;
use crate::util::ser::{
CursorReadable, HighZeroBytesDroppedBigSize, LengthLimitedRead, LengthReadable, Readable,
WithoutLength, Writeable, Writer,
};
use crate::util::string::PrintableString;
use bitcoin::constants::ChainHash;
use bitcoin::network::Network;
use bitcoin::secp256k1::{self, Keypair, PublicKey, Secp256k1};
use core::borrow::Borrow;
use core::hash::{Hash, Hasher};
use core::num::NonZeroU64;
use core::str::FromStr;
use core::time::Duration;
#[cfg(not(c_bindings))]
use crate::offers::invoice_request::InvoiceRequestBuilder;
#[cfg(c_bindings)]
use crate::offers::invoice_request::InvoiceRequestWithDerivedPayerSigningPubkeyBuilder;
#[allow(unused_imports)]
use crate::prelude::*;
use bitcoin::hex::impl_fmt_traits;
#[cfg(feature = "std")]
use std::time::SystemTime;
pub(super) const IV_BYTES_WITH_METADATA: &[u8; IV_LEN] = b"LDK Offer ~~~~~~";
pub(super) const IV_BYTES_WITHOUT_METADATA: &[u8; IV_LEN] = b"LDK Offer v2~~~~";
/// An identifier for an [`Offer`] built using [`DerivedMetadata`].
#[derive(Clone, Copy, Eq, PartialEq)]
pub struct OfferId(pub [u8; 32]);
impl OfferId {
const ID_TAG: &'static str = "LDK Offer ID";
fn from_valid_offer_tlv_stream(bytes: &[u8]) -> Self {
let tagged_hash = TaggedHash::from_valid_tlv_stream_bytes(Self::ID_TAG, bytes);
Self(tagged_hash.to_bytes())
}
fn from_valid_invreq_tlv_stream(bytes: &[u8]) -> Self {
let tlv_stream = Offer::tlv_stream_iter(bytes);
let tagged_hash = TaggedHash::from_tlv_stream(Self::ID_TAG, tlv_stream);
Self(tagged_hash.to_bytes())
}
}
impl Borrow<[u8]> for OfferId {
fn borrow(&self) -> &[u8] {
&self.0[..]
}
}
impl_fmt_traits! {
impl fmt_traits for OfferId {
const LENGTH: usize = 32;
}
}
impl Writeable for OfferId {
fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
self.0.write(w)
}
}
impl Readable for OfferId {
fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
Ok(OfferId(Readable::read(r)?))
}
}
/// Builds an [`Offer`] for the "offer to be paid" flow.
///
/// See [module-level documentation] for usage.
///
/// This is not exported to bindings users as builder patterns don't map outside of move semantics.
///
/// [module-level documentation]: self
pub struct OfferBuilder<'a, M: MetadataStrategy, T: secp256k1::Signing> {
offer: OfferContents,
metadata_strategy: core::marker::PhantomData<M>,
secp_ctx: Option<&'a Secp256k1<T>>,
}
/// Builds an [`Offer`] for the "offer to be paid" flow.
///
/// See [module-level documentation] for usage.
///
/// [module-level documentation]: self
#[cfg(c_bindings)]
#[derive(Clone)]
pub struct OfferWithExplicitMetadataBuilder<'a> {
offer: OfferContents,
metadata_strategy: core::marker::PhantomData<ExplicitMetadata>,
secp_ctx: Option<&'a Secp256k1<secp256k1::All>>,
}
/// Builds an [`Offer`] for the "offer to be paid" flow.
///
/// See [module-level documentation] for usage.
///
/// [module-level documentation]: self
#[cfg(c_bindings)]
#[derive(Clone)]
pub struct OfferWithDerivedMetadataBuilder<'a> {
offer: OfferContents,
metadata_strategy: core::marker::PhantomData<DerivedMetadata>,
secp_ctx: Option<&'a Secp256k1<secp256k1::All>>,
}
/// Indicates how [`Offer::metadata`] may be set.
///
/// This is not exported to bindings users as builder patterns don't map outside of move semantics.
pub trait MetadataStrategy {}
/// [`Offer::metadata`] may be explicitly set or left empty.
///
/// This is not exported to bindings users as builder patterns don't map outside of move semantics.
pub struct ExplicitMetadata {}
/// [`Offer::metadata`] will be derived.
///
/// This is not exported to bindings users as builder patterns don't map outside of move semantics.
pub struct DerivedMetadata {}
impl MetadataStrategy for ExplicitMetadata {}
impl MetadataStrategy for DerivedMetadata {}
macro_rules! offer_explicit_metadata_builder_methods {
(
$self: ident, $self_type: ty, $return_type: ty, $return_value: expr
) => {
/// Creates a new builder for an offer using the `signing_pubkey` for signing invoices. The
/// associated secret key must be remembered while the offer is valid.
///
/// Use a different pubkey per offer to avoid correlating offers.
///
/// # Note
///
/// If constructing an [`Offer`] for use with a [`ChannelManager`], use
/// [`ChannelManager::create_offer_builder`] instead of [`OfferBuilder::new`].
///
/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
/// [`ChannelManager::create_offer_builder`]: crate::ln::channelmanager::ChannelManager::create_offer_builder
pub fn new(signing_pubkey: PublicKey) -> Self {
Self {
offer: OfferContents {
chains: None,
metadata: None,
amount: None,
description: None,
features: OfferFeatures::empty(),
absolute_expiry: None,
issuer: None,
paths: None,
supported_quantity: Quantity::One,
issuer_signing_pubkey: Some(signing_pubkey),
#[cfg(test)]
experimental_foo: None,
},
metadata_strategy: core::marker::PhantomData,
secp_ctx: None,
}
}
/// Sets the [`Offer::metadata`] to the given bytes.
///
/// Successive calls to this method will override the previous setting.
pub fn metadata(
mut $self: $self_type, metadata: Vec<u8>,
) -> Result<$return_type, Bolt12SemanticError> {
$self.offer.metadata = Some(Metadata::Bytes(metadata));
Ok($return_value)
}
};
}
macro_rules! offer_derived_metadata_builder_methods {
($secp_context: ty) => {
/// Similar to [`OfferBuilder::new`] except, if [`OfferBuilder::path`] is called, the signing
/// pubkey is derived from the given [`ExpandedKey`] and [`Nonce`]. This provides recipient
/// privacy by using a different signing pubkey for each offer. Otherwise, the provided
/// `node_id` is used for [`Offer::issuer_signing_pubkey`].
///
/// Also, sets the metadata when [`OfferBuilder::build`] is called such that it can be used by
/// [`InvoiceRequest::verify_using_metadata`] to determine if the request was produced for the
/// offer given an [`ExpandedKey`]. However, if [`OfferBuilder::path`] is called, then the
/// metadata will not be set and must be included in each [`BlindedMessagePath`] instead. In this case,
/// use [`InvoiceRequest::verify_using_recipient_data`].
///
/// [`InvoiceRequest::verify_using_metadata`]: crate::offers::invoice_request::InvoiceRequest::verify_using_metadata
/// [`InvoiceRequest::verify_using_recipient_data`]: crate::offers::invoice_request::InvoiceRequest::verify_using_recipient_data
/// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
pub fn deriving_signing_pubkey(
node_id: PublicKey, expanded_key: &ExpandedKey, nonce: Nonce,
secp_ctx: &'a Secp256k1<$secp_context>,
) -> Self {
let derivation_material = MetadataMaterial::new(nonce, expanded_key, None);
let metadata = Metadata::DerivedSigningPubkey(derivation_material);
Self {
offer: OfferContents {
chains: None,
metadata: Some(metadata),
amount: None,
description: None,
features: OfferFeatures::empty(),
absolute_expiry: None,
issuer: None,
paths: None,
supported_quantity: Quantity::One,
issuer_signing_pubkey: Some(node_id),
#[cfg(test)]
experimental_foo: None,
},
metadata_strategy: core::marker::PhantomData,
secp_ctx: Some(secp_ctx),
}
}
};
}
macro_rules! offer_builder_methods { (
$self: ident, $self_type: ty, $return_type: ty, $return_value: expr $(, $self_mut: tt)?
) => {
/// Adds the chain hash of the given [`Network`] to [`Offer::chains`]. If not called,
/// the chain hash of [`Network::Bitcoin`] is assumed to be the only one supported.
///
/// See [`Offer::chains`] on how this relates to the payment currency.
///
/// Successive calls to this method will add another chain hash.
pub fn chain($self: $self_type, network: Network) -> $return_type {
$self.chain_hash(ChainHash::using_genesis_block(network))
}
/// Adds the [`ChainHash`] to [`Offer::chains`]. If not called, the chain hash of
/// [`Network::Bitcoin`] is assumed to be the only one supported.
///
/// See [`Offer::chains`] on how this relates to the payment currency.
///
/// Successive calls to this method will add another chain hash.
pub(crate) fn chain_hash($($self_mut)* $self: $self_type, chain: ChainHash) -> $return_type {
let chains = $self.offer.chains.get_or_insert_with(Vec::new);
if !chains.contains(&chain) {
chains.push(chain);
}
$return_value
}
/// Sets the [`Offer::amount`] as an [`Amount::Bitcoin`].
///
/// Successive calls to this method will override the previous setting.
pub fn amount_msats($self: $self_type, amount_msats: u64) -> $return_type {
$self.amount(Amount::Bitcoin { amount_msats })
}
/// Sets the [`Offer::amount`].
///
/// Successive calls to this method will override the previous setting.
pub(super) fn amount($($self_mut)* $self: $self_type, amount: Amount) -> $return_type {
$self.offer.amount = Some(amount);
$return_value
}
/// Sets the [`Offer::absolute_expiry`] as seconds since the Unix epoch.
#[cfg_attr(feature = "std", doc = "Any expiry that has already passed is valid and can be checked for using [`Offer::is_expired`].")]
///
/// Successive calls to this method will override the previous setting.
pub fn absolute_expiry($($self_mut)* $self: $self_type, absolute_expiry: Duration) -> $return_type {
$self.offer.absolute_expiry = Some(absolute_expiry);
$return_value
}
/// Sets the [`Offer::description`].
///
/// Successive calls to this method will override the previous setting.
pub fn description($($self_mut)* $self: $self_type, description: String) -> $return_type {
$self.offer.description = Some(description);
$return_value
}
/// Sets the [`Offer::issuer`].
///
/// Successive calls to this method will override the previous setting.
pub fn issuer($($self_mut)* $self: $self_type, issuer: String) -> $return_type {
$self.offer.issuer = Some(issuer);
$return_value
}
/// Adds a blinded path to [`Offer::paths`]. Must include at least one path if only connected by
/// private channels or if [`Offer::issuer_signing_pubkey`] is not a public node id.
///
/// Successive calls to this method will add another blinded path. Caller is responsible for not
/// adding duplicate paths.
pub fn path($($self_mut)* $self: $self_type, path: BlindedMessagePath) -> $return_type {
$self.offer.paths.get_or_insert_with(Vec::new).push(path);
$return_value
}
/// Sets the quantity of items for [`Offer::supported_quantity`]. If not called, defaults to
/// [`Quantity::One`].
///
/// Successive calls to this method will override the previous setting.
pub fn supported_quantity($($self_mut)* $self: $self_type, quantity: Quantity) -> $return_type {
$self.offer.supported_quantity = quantity;
$return_value
}
/// Builds an [`Offer`] from the builder's settings.
pub fn build($($self_mut)* $self: $self_type) -> Result<Offer, Bolt12SemanticError> {
match $self.offer.amount {
Some(Amount::Bitcoin { amount_msats }) => {
if amount_msats > MAX_VALUE_MSAT {
return Err(Bolt12SemanticError::InvalidAmount);
}
},
Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
None => {},
}
if $self.offer.amount.is_some() && $self.offer.description.is_none() {
$self.offer.description = Some(String::new());
}
if let Some(chains) = &$self.offer.chains {
if chains.len() == 1 && chains[0] == $self.offer.implied_chain() {
$self.offer.chains = None;
}
}
Ok($self.build_without_checks())
}
fn build_without_checks($($self_mut)* $self: $self_type) -> Offer {
if let Some(mut metadata) = $self.offer.metadata.take() {
// Create the metadata for stateless verification of an InvoiceRequest.
if metadata.has_derivation_material() {
// Don't derive keys if no blinded paths were given since this means the signing
// pubkey must be the node id of an announced node.
let iv_bytes = if $self.offer.paths.is_none() {
metadata = metadata.without_keys();
IV_BYTES_WITH_METADATA
} else {
IV_BYTES_WITHOUT_METADATA
};
let mut tlv_stream = $self.offer.as_tlv_stream();
debug_assert_eq!(tlv_stream.0.metadata, None);
tlv_stream.0.metadata = None;
if metadata.derives_recipient_keys() {
tlv_stream.0.issuer_id = None;
}
// Either replace the signing pubkey with the derived pubkey or include the metadata
// for verification. In the former case, the blinded paths must include
// `OffersContext::InvoiceRequest` instead.
let (derived_metadata, keys) =
metadata.derive_from(iv_bytes, tlv_stream, $self.secp_ctx);
match keys {
Some(keys) => $self.offer.issuer_signing_pubkey = Some(keys.public_key()),
None => $self.offer.metadata = Some(derived_metadata),
}
} else {
$self.offer.metadata = Some(metadata);
}
}
const OFFER_ALLOCATION_SIZE: usize = 512;
let mut bytes = Vec::with_capacity(OFFER_ALLOCATION_SIZE);
$self.offer.write(&mut bytes).unwrap();
let id = OfferId::from_valid_offer_tlv_stream(&bytes);
Offer {
bytes,
#[cfg(not(c_bindings))]
contents: $self.offer,
#[cfg(c_bindings)]
contents: $self.offer.clone(),
id,
}
}
} }
#[cfg(test)]
macro_rules! offer_builder_test_methods { (
$self: ident, $self_type: ty, $return_type: ty, $return_value: expr $(, $self_mut: tt)?
) => {
#[cfg_attr(c_bindings, allow(dead_code))]
fn features_unchecked($($self_mut)* $self: $self_type, features: OfferFeatures) -> $return_type {
$self.offer.features = features;
$return_value
}
#[cfg_attr(c_bindings, allow(dead_code))]
pub(crate) fn clear_chains($($self_mut)* $self: $self_type) -> $return_type {
$self.offer.chains = None;
$return_value
}
#[cfg_attr(c_bindings, allow(dead_code))]
pub(crate) fn clear_paths($($self_mut)* $self: $self_type) -> $return_type {
$self.offer.paths = None;
$return_value
}
#[cfg_attr(c_bindings, allow(dead_code))]
pub(crate) fn clear_issuer_signing_pubkey($($self_mut)* $self: $self_type) -> $return_type {
$self.offer.issuer_signing_pubkey = None;
$return_value
}
#[cfg_attr(c_bindings, allow(dead_code))]
pub(super) fn experimental_foo($($self_mut)* $self: $self_type, experimental_foo: u64) -> $return_type {
$self.offer.experimental_foo = Some(experimental_foo);
$return_value
}
#[cfg_attr(c_bindings, allow(dead_code))]
pub(super) fn build_unchecked($self: $self_type) -> Offer {
$self.build_without_checks()
}
} }
impl<'a, M: MetadataStrategy, T: secp256k1::Signing> OfferBuilder<'a, M, T> {
offer_builder_methods!(self, Self, Self, self, mut);
#[cfg(test)]
offer_builder_test_methods!(self, Self, Self, self, mut);
}
impl<'a> OfferBuilder<'a, ExplicitMetadata, secp256k1::SignOnly> {
offer_explicit_metadata_builder_methods!(self, Self, Self, self);
}
impl<'a, T: secp256k1::Signing> OfferBuilder<'a, DerivedMetadata, T> {
offer_derived_metadata_builder_methods!(T);
}
#[cfg(all(c_bindings, not(test)))]
impl<'a> OfferWithExplicitMetadataBuilder<'a> {
offer_explicit_metadata_builder_methods!(self, &mut Self, (), ());
offer_builder_methods!(self, &mut Self, (), ());
}
#[cfg(all(c_bindings, test))]
impl<'a> OfferWithExplicitMetadataBuilder<'a> {
offer_explicit_metadata_builder_methods!(self, &mut Self, &mut Self, self);
offer_builder_methods!(self, &mut Self, &mut Self, self);
offer_builder_test_methods!(self, &mut Self, &mut Self, self);
}
#[cfg(all(c_bindings, not(test)))]
impl<'a> OfferWithDerivedMetadataBuilder<'a> {
offer_derived_metadata_builder_methods!(secp256k1::All);
offer_builder_methods!(self, &mut Self, (), ());
}
#[cfg(all(c_bindings, test))]
impl<'a> OfferWithDerivedMetadataBuilder<'a> {
offer_derived_metadata_builder_methods!(secp256k1::All);
offer_builder_methods!(self, &mut Self, &mut Self, self);
offer_builder_test_methods!(self, &mut Self, &mut Self, self);
}
#[cfg(c_bindings)]
impl<'a> From<OfferBuilder<'a, DerivedMetadata, secp256k1::All>>
for OfferWithDerivedMetadataBuilder<'a>
{
fn from(builder: OfferBuilder<'a, DerivedMetadata, secp256k1::All>) -> Self {
let OfferBuilder { offer, metadata_strategy, secp_ctx } = builder;
Self { offer, metadata_strategy, secp_ctx }
}
}
#[cfg(c_bindings)]
impl<'a> From<OfferWithDerivedMetadataBuilder<'a>>
for OfferBuilder<'a, DerivedMetadata, secp256k1::All>
{
fn from(builder: OfferWithDerivedMetadataBuilder<'a>) -> Self {
let OfferWithDerivedMetadataBuilder { offer, metadata_strategy, secp_ctx } = builder;
Self { offer, metadata_strategy, secp_ctx }
}
}
/// An `Offer` is a potentially long-lived proposal for payment of a good or service.
///
/// An offer is a precursor to an [`InvoiceRequest`]. A merchant publishes an offer from which a
/// customer may request an [`Bolt12Invoice`] for a specific quantity and using an amount sufficient
/// to cover that quantity (i.e., at least `quantity * amount`). See [`Offer::amount`].
///
/// Offers may be denominated in currency other than bitcoin but are ultimately paid using the
/// latter.
///
/// Through the use of [`BlindedMessagePath`]s, offers provide recipient privacy.
///
/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
#[derive(Clone, Debug)]
pub struct Offer {
// The serialized offer. Needed when creating an `InvoiceRequest` if the offer contains unknown
// fields.
pub(super) bytes: Vec<u8>,
pub(super) contents: OfferContents,
id: OfferId,
}
/// The contents of an [`Offer`], which may be shared with an [`InvoiceRequest`] or a
/// [`Bolt12Invoice`].
///
/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
#[derive(Clone, Debug, Hash)]
#[cfg_attr(test, derive(PartialEq))]
pub(super) struct OfferContents {
chains: Option<Vec<ChainHash>>,
metadata: Option<Metadata>,
amount: Option<Amount>,
description: Option<String>,
features: OfferFeatures,
absolute_expiry: Option<Duration>,
issuer: Option<String>,
paths: Option<Vec<BlindedMessagePath>>,
supported_quantity: Quantity,
issuer_signing_pubkey: Option<PublicKey>,
#[cfg(test)]
experimental_foo: Option<u64>,
}
macro_rules! offer_accessors { ($self: ident, $contents: expr) => {
// TODO: Return a slice once ChainHash has constants.
// - https://github.com/rust-bitcoin/rust-bitcoin/pull/1283
// - https://github.com/rust-bitcoin/rust-bitcoin/pull/1286
/// The chains that may be used when paying a requested invoice (e.g., bitcoin mainnet).
/// Payments must be denominated in units of the minimal lightning-payable unit (e.g., msats)
/// for the selected chain.
pub fn chains(&$self) -> Vec<bitcoin::constants::ChainHash> {
$contents.chains()
}
// TODO: Link to corresponding method in `InvoiceRequest`.
/// Opaque bytes set by the originator. Useful for authentication and validating fields since it
/// is reflected in `invoice_request` messages along with all the other fields from the `offer`.
pub fn metadata(&$self) -> Option<&Vec<u8>> {
$contents.metadata()
}
/// The minimum amount required for a successful payment of a single item.
pub fn amount(&$self) -> Option<$crate::offers::offer::Amount> {
$contents.amount()
}
/// A complete description of the purpose of the payment. Intended to be displayed to the user
/// but with the caveat that it has not been verified in any way.
pub fn description(&$self) -> Option<$crate::util::string::PrintableString> {
$contents.description()
}
/// Features pertaining to the offer.
pub fn offer_features(&$self) -> &$crate::types::features::OfferFeatures {
&$contents.features()
}
/// Duration since the Unix epoch when an invoice should no longer be requested.
///
/// If `None`, the offer does not expire.
pub fn absolute_expiry(&$self) -> Option<core::time::Duration> {
$contents.absolute_expiry()
}
/// The issuer of the offer, possibly beginning with `user@domain` or `domain`. Intended to be
/// displayed to the user but with the caveat that it has not been verified in any way.
pub fn issuer(&$self) -> Option<$crate::util::string::PrintableString> {
$contents.issuer()
}
/// Paths to the recipient originating from publicly reachable nodes. Blinded paths provide
/// recipient privacy by obfuscating its node id.
pub fn paths(&$self) -> &[$crate::blinded_path::message::BlindedMessagePath] {
$contents.paths()
}
/// The quantity of items supported.
pub fn supported_quantity(&$self) -> $crate::offers::offer::Quantity {
$contents.supported_quantity()
}
/// The public key corresponding to the key used by the recipient to sign invoices.
/// - If [`Offer::paths`] is empty, MUST be `Some` and contain the recipient's node id for
/// sending an [`InvoiceRequest`].
/// - If [`Offer::paths`] is not empty, MAY be `Some` and contain a transient id.
/// - If `None`, the signing pubkey will be the final blinded node id from the
/// [`BlindedMessagePath`] in [`Offer::paths`] used to send the [`InvoiceRequest`].
///
/// See also [`Bolt12Invoice::signing_pubkey`].
///
/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
/// [`Bolt12Invoice::signing_pubkey`]: crate::offers::invoice::Bolt12Invoice::signing_pubkey
pub fn issuer_signing_pubkey(&$self) -> Option<bitcoin::secp256k1::PublicKey> {
$contents.issuer_signing_pubkey()
}
} }
impl Offer {
offer_accessors!(self, self.contents);
/// Returns the id of the offer.
pub fn id(&self) -> OfferId {
self.id
}
pub(super) fn implied_chain(&self) -> ChainHash {
self.contents.implied_chain()
}
/// Returns whether the given chain is supported by the offer.
pub fn supports_chain(&self, chain: ChainHash) -> bool {
self.contents.supports_chain(chain)
}
/// Whether the offer has expired.
#[cfg(feature = "std")]
pub fn is_expired(&self) -> bool {
self.contents.is_expired()
}
/// Whether the offer has expired given the duration since the Unix epoch.
pub fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
self.contents.is_expired_no_std(duration_since_epoch)
}
/// Returns whether the given quantity is valid for the offer.
pub fn is_valid_quantity(&self, quantity: u64) -> bool {
self.contents.is_valid_quantity(quantity)
}
/// Returns whether a quantity is expected in an [`InvoiceRequest`] for the offer.
///
/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
pub fn expects_quantity(&self) -> bool {
self.contents.expects_quantity()
}
pub(super) fn tlv_stream_iter<'a>(
bytes: &'a [u8],
) -> impl core::iter::Iterator<Item = TlvRecord<'a>> {
TlvStream::new(bytes)
.range(OFFER_TYPES)
.chain(TlvStream::new(bytes).range(EXPERIMENTAL_OFFER_TYPES))
}
pub(super) fn verify<T: secp256k1::Signing>(
&self, nonce: Nonce, key: &ExpandedKey, secp_ctx: &Secp256k1<T>,
) -> Result<(OfferId, Option<Keypair>), ()> {
self.contents.verify_using_recipient_data(&self.bytes, nonce, key, secp_ctx)
}
}
macro_rules! request_invoice_derived_signing_pubkey { ($self: ident, $builder: ty) => {
/// Creates an [`InvoiceRequestBuilder`] for the offer, which
/// - derives the [`InvoiceRequest::payer_signing_pubkey`] such that a different key can be used
/// for each request in order to protect the sender's privacy,
/// - sets [`InvoiceRequest::payer_metadata`] when [`InvoiceRequestBuilder::build_and_sign`] is
/// called such that it can be used by [`Bolt12Invoice::verify_using_metadata`] to determine
/// if the invoice was requested using a base [`ExpandedKey`] from which the payer id was
/// derived, and
/// - includes the [`PaymentId`] encrypted in [`InvoiceRequest::payer_metadata`] so that it can
/// be used when sending the payment for the requested invoice.
///
/// Errors if the offer contains unknown required features.
///
/// [`InvoiceRequest::payer_signing_pubkey`]: crate::offers::invoice_request::InvoiceRequest::payer_signing_pubkey
/// [`InvoiceRequest::payer_metadata`]: crate::offers::invoice_request::InvoiceRequest::payer_metadata
/// [`Bolt12Invoice::verify_using_metadata`]: crate::offers::invoice::Bolt12Invoice::verify_using_metadata
/// [`ExpandedKey`]: crate::ln::inbound_payment::ExpandedKey
pub fn request_invoice<
'a, 'b,
#[cfg(not(c_bindings))]
T: secp256k1::Signing
>(
&'a $self, expanded_key: &ExpandedKey, nonce: Nonce,
#[cfg(not(c_bindings))]
secp_ctx: &'b Secp256k1<T>,
#[cfg(c_bindings)]
secp_ctx: &'b Secp256k1<secp256k1::All>,
payment_id: PaymentId
) -> Result<$builder, Bolt12SemanticError> {
if $self.offer_features().requires_unknown_bits() {
return Err(Bolt12SemanticError::UnknownRequiredFeatures);
}
Ok(<$builder>::deriving_signing_pubkey($self, expanded_key, nonce, secp_ctx, payment_id))
}
} }
#[cfg(not(c_bindings))]
impl Offer {
request_invoice_derived_signing_pubkey!(self, InvoiceRequestBuilder<'a, 'b, T>);
}
#[cfg(c_bindings)]
impl Offer {
request_invoice_derived_signing_pubkey!(
self,
InvoiceRequestWithDerivedPayerSigningPubkeyBuilder<'a, 'b>
);
}
#[cfg(test)]
impl Offer {
pub(super) fn as_tlv_stream(&self) -> FullOfferTlvStreamRef {
self.contents.as_tlv_stream()
}
}
impl AsRef<[u8]> for Offer {
fn as_ref(&self) -> &[u8] {
&self.bytes
}
}
impl PartialEq for Offer {
fn eq(&self, other: &Self) -> bool {
self.bytes.eq(&other.bytes)
}
}
impl Eq for Offer {}
impl Hash for Offer {
fn hash<H: Hasher>(&self, state: &mut H) {
self.bytes.hash(state);
}
}
impl OfferContents {
pub fn chains(&self) -> Vec<ChainHash> {
self.chains.as_ref().cloned().unwrap_or_else(|| vec![self.implied_chain()])
}
pub fn implied_chain(&self) -> ChainHash {
ChainHash::using_genesis_block(Network::Bitcoin)
}
pub fn supports_chain(&self, chain: ChainHash) -> bool {
self.chains().contains(&chain)
}
pub fn metadata(&self) -> Option<&Vec<u8>> {
self.metadata.as_ref().and_then(|metadata| metadata.as_bytes())
}
pub fn amount(&self) -> Option<Amount> {
self.amount
}
pub fn description(&self) -> Option<PrintableString> {
self.description.as_ref().map(|description| PrintableString(description))
}
pub fn features(&self) -> &OfferFeatures {
&self.features
}
pub fn absolute_expiry(&self) -> Option<Duration> {
self.absolute_expiry
}
#[cfg(feature = "std")]
pub(super) fn is_expired(&self) -> bool {
SystemTime::UNIX_EPOCH
.elapsed()
.map(|duration_since_epoch| self.is_expired_no_std(duration_since_epoch))
.unwrap_or(false)
}
pub(super) fn is_expired_no_std(&self, duration_since_epoch: Duration) -> bool {
self.absolute_expiry
.map(|absolute_expiry| duration_since_epoch > absolute_expiry)
.unwrap_or(false)
}
pub fn issuer(&self) -> Option<PrintableString> {
self.issuer.as_ref().map(|issuer| PrintableString(issuer.as_str()))
}
pub fn paths(&self) -> &[BlindedMessagePath] {
self.paths.as_ref().map(|paths| paths.as_slice()).unwrap_or(&[])
}
pub(super) fn check_amount_msats_for_quantity(
&self, amount_msats: Option<u64>, quantity: Option<u64>,
) -> Result<(), Bolt12SemanticError> {
let offer_amount_msats = match self.amount {
None => 0,
Some(Amount::Bitcoin { amount_msats }) => amount_msats,
Some(Amount::Currency { .. }) => return Err(Bolt12SemanticError::UnsupportedCurrency),
};
if !self.expects_quantity() || quantity.is_some() {
let expected_amount_msats = offer_amount_msats
.checked_mul(quantity.unwrap_or(1))
.ok_or(Bolt12SemanticError::InvalidAmount)?;
let amount_msats = amount_msats.unwrap_or(expected_amount_msats);
if amount_msats < expected_amount_msats {
return Err(Bolt12SemanticError::InsufficientAmount);
}
if amount_msats > MAX_VALUE_MSAT {
return Err(Bolt12SemanticError::InvalidAmount);
}
}
Ok(())
}
pub fn supported_quantity(&self) -> Quantity {
self.supported_quantity
}
pub(super) fn check_quantity(&self, quantity: Option<u64>) -> Result<(), Bolt12SemanticError> {
let expects_quantity = self.expects_quantity();
match quantity {
None if expects_quantity => Err(Bolt12SemanticError::MissingQuantity),
Some(_) if !expects_quantity => Err(Bolt12SemanticError::UnexpectedQuantity),
Some(quantity) if !self.is_valid_quantity(quantity) => {
Err(Bolt12SemanticError::InvalidQuantity)
},
_ => Ok(()),
}
}
fn is_valid_quantity(&self, quantity: u64) -> bool {
match self.supported_quantity {
Quantity::Bounded(n) => quantity <= n.get(),
Quantity::Unbounded => quantity > 0,
Quantity::One => quantity == 1,
}
}
fn expects_quantity(&self) -> bool {
match self.supported_quantity {
Quantity::Bounded(_) => true,
Quantity::Unbounded => true,
Quantity::One => false,
}
}
pub(super) fn issuer_signing_pubkey(&self) -> Option<PublicKey> {
self.issuer_signing_pubkey
}
pub(super) fn verify_using_metadata<T: secp256k1::Signing>(
&self, bytes: &[u8], key: &ExpandedKey, secp_ctx: &Secp256k1<T>,
) -> Result<(OfferId, Option<Keypair>), ()> {
self.verify(bytes, self.metadata.as_ref(), key, IV_BYTES_WITH_METADATA, secp_ctx)
}
pub(super) fn verify_using_recipient_data<T: secp256k1::Signing>(
&self, bytes: &[u8], nonce: Nonce, key: &ExpandedKey, secp_ctx: &Secp256k1<T>,
) -> Result<(OfferId, Option<Keypair>), ()> {
let metadata = Metadata::RecipientData(nonce);
self.verify(bytes, Some(&metadata), key, IV_BYTES_WITHOUT_METADATA, secp_ctx)
}
/// Verifies that the offer metadata was produced from the offer in the TLV stream.
fn verify<T: secp256k1::Signing>(
&self, bytes: &[u8], metadata: Option<&Metadata>, key: &ExpandedKey,
iv_bytes: &[u8; IV_LEN], secp_ctx: &Secp256k1<T>,
) -> Result<(OfferId, Option<Keypair>), ()> {
match metadata {
Some(metadata) => {
let tlv_stream = TlvStream::new(bytes)
.range(OFFER_TYPES)
.filter(|record| match record.r#type {
OFFER_METADATA_TYPE => false,
OFFER_ISSUER_ID_TYPE => !metadata.derives_recipient_keys(),
_ => true,
})
.chain(TlvStream::new(bytes).range(EXPERIMENTAL_OFFER_TYPES));
let signing_pubkey = match self.issuer_signing_pubkey() {
Some(signing_pubkey) => signing_pubkey,
None => return Err(()),
};
let keys = signer::verify_recipient_metadata(
metadata.as_ref(),
key,
iv_bytes,
signing_pubkey,
tlv_stream,
secp_ctx,
)?;
let offer_id = OfferId::from_valid_invreq_tlv_stream(bytes);
Ok((offer_id, keys))
},
None => Err(()),
}
}
pub(super) fn as_tlv_stream(&self) -> FullOfferTlvStreamRef {
let (currency, amount) = match &self.amount {
None => (None, None),