Create normal/phantom invoice with description hash

Author: luizParreira

lightning-invoice/src/utils.rs

@@ -3,9 +3,9 @@
 use {CreationError, Currency, DEFAULT_EXPIRY_TIME, Invoice, InvoiceBuilder, SignOrCreationError};
 use payment::{Payer, Router};
 
+use crate::{prelude::*, Description, InvoiceDescription};
 use bech32::ToBase32;
 use bitcoin_hashes::{Hash, sha256};
-use crate::prelude::*;
 use lightning::chain;
 use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
 use lightning::chain::keysinterface::{Recipient, KeysInterface, Sign};
@@ -50,14 +50,96 @@ use sync::Mutex;
 /// [`ChannelManager::get_phantom_route_hints`]: lightning::ln::channelmanager::ChannelManager::get_phantom_route_hints
 /// [`PhantomRouteHints::channels`]: lightning::ln::channelmanager::PhantomRouteHints::channels
 pub fn create_phantom_invoice<Signer: Sign, K: Deref>(
-	amt_msat: Option<u64>, description: String, payment_hash: PaymentHash, payment_secret:
-	PaymentSecret, phantom_route_hints: Vec<PhantomRouteHints>, keys_manager: K, network: Currency
-) -> Result<Invoice, SignOrCreationError<()>> where K::Target: KeysInterface {
+	amt_msat: Option<u64>,
+	description: String,
+	payment_hash: PaymentHash,
+	payment_secret: PaymentSecret,
+	phantom_route_hints: Vec<PhantomRouteHints>,
+	keys_manager: K,
+	network: Currency,
+) -> Result<Invoice, SignOrCreationError<()>>
+where
+	K::Target: KeysInterface,
+{
+	let description = Description::new(description).map_err(SignOrCreationError::CreationError)?;
+	let description = InvoiceDescription::Direct(&description,);
+	_create_phantom_invoice::<Signer, K>(
+		amt_msat, description, payment_hash, payment_secret, phantom_route_hints, keys_manager, network,
+	)
+}
+
+#[cfg(feature = "std")]
+/// Utility to create an invoice that can be paid to one of multiple nodes, or a "phantom invoice."
+/// See [`PhantomKeysManager`] for more information on phantom node payments.
+///
+/// `phantom_route_hints` parameter:
+/// * Contains channel info for all nodes participating in the phantom invoice
+/// * Entries are retrieved from a call to [`ChannelManager::get_phantom_route_hints`] on each
+///   participating node
+/// * It is fine to cache `phantom_route_hints` and reuse it across invoices, as long as the data is
+///   updated when a channel becomes disabled or closes
+/// * Note that if too many channels are included in [`PhantomRouteHints::channels`], the invoice
+///   may be too long for QR code scanning. To fix this, `PhantomRouteHints::channels` may be pared
+///   down
+///
+/// `description` will be SHA-256 hashed and transformed in `description_hash` on the invoice
+///
+/// `payment_hash` and `payment_secret` come from [`ChannelManager::create_inbound_payment`] or
+/// [`ChannelManager::create_inbound_payment_for_hash`]. These values can be retrieved from any
+/// participating node.
+///
+/// Note that the provided `keys_manager`'s `KeysInterface` implementation must support phantom
+/// invoices in its `sign_invoice` implementation ([`PhantomKeysManager`] satisfies this
+/// requirement).
+///
+/// [`PhantomKeysManager`]: lightning::chain::keysinterface::PhantomKeysManager
+/// [`ChannelManager::get_phantom_route_hints`]: lightning::ln::channelmanager::ChannelManager::get_phantom_route_hints
+/// [`PhantomRouteHints::channels`]: lightning::ln::channelmanager::PhantomRouteHints::channels
+pub fn create_phantom_invoice_with_description_hash<Signer: Sign, K: Deref>(
+	amt_msat: Option<u64>,
+	description: String,
+	payment_hash: PaymentHash,
+	payment_secret: PaymentSecret,
+	phantom_route_hints: Vec<PhantomRouteHints>,
+	keys_manager: K,
+	network: Currency,
+) -> Result<Invoice, SignOrCreationError<()>>
+where
+	K::Target: KeysInterface,
+{
+	_create_phantom_invoice::<Signer, K>(
+		amt_msat,
+		InvoiceDescription::Hash(&crate::Sha256(Hash::hash(description.as_bytes()))),
+		payment_hash, payment_secret, phantom_route_hints, keys_manager, network,
+	)
+}
+
+#[cfg(feature = "std")]
+fn _create_phantom_invoice<Signer: Sign, K: Deref>(
+	amt_msat: Option<u64>,
+	description: InvoiceDescription,
+	payment_hash: PaymentHash,
+	payment_secret: PaymentSecret,
+	phantom_route_hints: Vec<PhantomRouteHints>,
+	keys_manager: K,
+	network: Currency,
+) -> Result<Invoice, SignOrCreationError<()>>
+where
+	K::Target: KeysInterface,
+{
 	if phantom_route_hints.len() == 0 {
-		return Err(SignOrCreationError::CreationError(CreationError::MissingRouteHints))
+		return Err(SignOrCreationError::CreationError(
+			CreationError::MissingRouteHints,
+		));
 	}
-	let mut invoice = InvoiceBuilder::new(network)
-		.description(description)
+	let invoice = match description {
+		InvoiceDescription::Direct(description) => {
+			InvoiceBuilder::new(network).description(description.0.clone())
+		}
+		InvoiceDescription::Hash(hash) => InvoiceBuilder::new(network).description_hash(hash.0),
+	};
+
+	let mut invoice = invoice
 		.current_timestamp()
 		.payment_hash(Hash::from_slice(&payment_hash.0).unwrap())
 		.payment_secret(payment_secret)
@@ -126,12 +208,78 @@ where
 	let duration = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH)
 		.expect("for the foreseeable future this shouldn't happen");
 	create_invoice_from_channelmanager_and_duration_since_epoch(
-		channelmanager,
-		keys_manager,
-		network,
-		amt_msat,
-		description,
-		duration
+		channelmanager, keys_manager, network, amt_msat, description, duration
+	)
+}
+
+#[cfg(feature = "std")]
+/// Utility to construct an invoice. Generally, unless you want to do something like a custom
+/// cltv_expiry, this is what you should be using to create an invoice. The reason being, this
+/// method stores the invoice's payment secret and preimage in `ChannelManager`, so (a) the user
+/// doesn't have to store preimage/payment secret information and (b) `ChannelManager` can verify
+/// that the payment secret is valid when the invoice is paid.
+/// Use this variant if you want to hash the description and pass a `payment_hash` instead
+pub fn create_invoice_from_channelmanager_with_description_hash<
+	Signer: Sign,
+	M: Deref,
+	T: Deref,
+	K: Deref,
+	F: Deref,
+	L: Deref,
+>(
+	channelmanager: &ChannelManager<Signer, M, T, K, F, L>,
+	keys_manager: K,
+	network: Currency,
+	amt_msat: Option<u64>,
+	description: String,
+) -> Result<Invoice, SignOrCreationError<()>>
+where
+	M::Target: chain::Watch<Signer>,
+	T::Target: BroadcasterInterface,
+	K::Target: KeysInterface<Signer = Signer>,
+	F::Target: FeeEstimator,
+	L::Target: Logger,
+{
+	use std::time::SystemTime;
+
+	let duration = SystemTime::now()
+		.duration_since(SystemTime::UNIX_EPOCH)
+		.expect("for the foreseeable future this shouldn't happen");
+
+	create_invoice_from_channelmanager_with_description_hash_and_duration_since_epoch(
+		channelmanager, keys_manager, network, amt_msat, description, duration,
+	)
+}
+
+/// See [`create_invoice_from_channelmanager_with_description_hash`]
+/// This version can be used in a `no_std` environment, where [`std::time::SystemTime`] is not
+/// available and the current time is supplied by the caller.
+pub fn create_invoice_from_channelmanager_with_description_hash_and_duration_since_epoch<
+	Signer: Sign,
+	M: Deref,
+	T: Deref,
+	K: Deref,
+	F: Deref,
+	L: Deref,
+>(
+	channelmanager: &ChannelManager<Signer, M, T, K, F, L>,
+	keys_manager: K,
+	network: Currency,
+	amt_msat: Option<u64>,
+	description: String,
+	duration_since_epoch: Duration,
+) -> Result<Invoice, SignOrCreationError<()>>
+where
+	M::Target: chain::Watch<Signer>,
+	T::Target: BroadcasterInterface,
+	K::Target: KeysInterface<Signer = Signer>,
+	F::Target: FeeEstimator,
+	L::Target: Logger,
+{
+	_create_invoice_from_channelmanager_and_duration_since_epoch(
+		channelmanager, keys_manager, network, amt_msat,
+		InvoiceDescription::Hash(&crate::Sha256(Hash::hash(description.as_bytes()))),
+		duration_since_epoch,
 	)
 }
 
@@ -142,6 +290,37 @@ pub fn create_invoice_from_channelmanager_and_duration_since_epoch<Signer: Sign,
 	channelmanager: &ChannelManager<Signer, M, T, K, F, L>, keys_manager: K, network: Currency,
 	amt_msat: Option<u64>, description: String, duration_since_epoch: Duration,
 ) -> Result<Invoice, SignOrCreationError<()>>
+where
+	M::Target: chain::Watch<Signer>,
+	T::Target: BroadcasterInterface,
+	K::Target: KeysInterface<Signer = Signer>,
+	F::Target: FeeEstimator,
+	L::Target: Logger,
+{
+	_create_invoice_from_channelmanager_and_duration_since_epoch(
+		channelmanager, keys_manager, network, amt_msat,
+		InvoiceDescription::Direct(
+			&Description::new(description).map_err(SignOrCreationError::CreationError)?,
+		),
+		duration_since_epoch,
+	)
+}
+
+fn _create_invoice_from_channelmanager_and_duration_since_epoch<
+	Signer: Sign,
+	M: Deref,
+	T: Deref,
+	K: Deref,
+	F: Deref,
+	L: Deref,
+>(
+	channelmanager: &ChannelManager<Signer, M, T, K, F, L>,
+	keys_manager: K,
+	network: Currency,
+	amt_msat: Option<u64>,
+	description: InvoiceDescription,
+	duration_since_epoch: Duration,
+) -> Result<Invoice, SignOrCreationError<()>>
 where
 	M::Target: chain::Watch<Signer>,
 	T::Target: BroadcasterInterface,
@@ -153,12 +332,19 @@ where
 
 	// `create_inbound_payment` only returns an error if the amount is greater than the total bitcoin
 	// supply.
-	let (payment_hash, payment_secret) = channelmanager.create_inbound_payment(
-		amt_msat, DEFAULT_EXPIRY_TIME.try_into().unwrap())
+	let (payment_hash, payment_secret) = channelmanager
+		.create_inbound_payment(amt_msat, DEFAULT_EXPIRY_TIME.try_into().unwrap())
 		.map_err(|()| SignOrCreationError::CreationError(CreationError::InvalidAmount))?;
 	let our_node_pubkey = channelmanager.get_our_node_id();
-	let mut invoice = InvoiceBuilder::new(network)
-		.description(description)
+
+	let invoice = match description {
+		InvoiceDescription::Direct(description) => {
+			InvoiceBuilder::new(network).description(description.0.clone())
+		}
+		InvoiceDescription::Hash(hash) => InvoiceBuilder::new(network).description_hash(hash.0),
+	};
+
+	let mut invoice = invoice
 		.duration_since_epoch(duration_since_epoch)
 		.payee_pub_key(our_node_pubkey)
 		.payment_hash(Hash::from_slice(&payment_hash.0).unwrap())
@@ -407,6 +593,31 @@ mod test {
 		assert_eq!(events.len(), 2);
 	}
 
+	#[test]
+	fn test_create_invoice_with_description_hash() {
+		let chanmon_cfgs = create_chanmon_cfgs(2);
+		let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+		let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+		let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+
+		let invoice = ::utils::create_invoice_from_channelmanager_with_description_hash_and_duration_since_epoch(
+			&nodes[1].node, nodes[1].keys_manager, Currency::BitcoinTestnet, Some(10_000),
+			"Testing description_hash".to_string(), Duration::from_secs(1234567),
+		)
+		.unwrap();
+		assert_eq!(invoice.amount_pico_btc(), Some(100_000));
+		assert_eq!(
+			invoice.min_final_cltv_expiry(),
+			MIN_FINAL_CLTV_EXPIRY as u64
+		);
+		assert_eq!(
+			invoice.description(),
+			InvoiceDescription::Hash(&crate::Sha256(Sha256::hash(
+				"Testing description_hash".as_bytes()
+			)))
+		);
+	}
+
 	#[test]
 	fn test_hints_includes_single_channels_to_nodes() {
 		let chanmon_cfgs = create_chanmon_cfgs(3);
@@ -1015,4 +1226,55 @@ mod test {
 		}
 		assert!(chan_ids_to_match.is_empty(), "Unmatched short channel ids: {:?}", chan_ids_to_match);
 	}
+
+	#[test]
+	#[cfg(feature = "std")]
+	fn create_phantom_invoice_with_description_hash() {
+		let mut chanmon_cfgs = create_chanmon_cfgs(3);
+		let seed_1 = [42 as u8; 32];
+		let seed_2 = [43 as u8; 32];
+		let cross_node_seed = [44 as u8; 32];
+		chanmon_cfgs[1].keys_manager.backing = PhantomKeysManager::new(&seed_1, 43, 44, &cross_node_seed);
+		chanmon_cfgs[2].keys_manager.backing =PhantomKeysManager::new(&seed_2, 43, 44, &cross_node_seed);
+		let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
+		let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
+		let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
+		let chan_0_1 = create_announced_chan_between_nodes_with_value(
+			&nodes, 0, 1, 100000, 10001, InitFeatures::known(), InitFeatures::known(),
+		);
+		nodes[0].node.handle_channel_update(&nodes[1].node.get_our_node_id(), &chan_0_1.1);
+		nodes[1].node.handle_channel_update(&nodes[0].node.get_our_node_id(), &chan_0_1.0);
+		let chan_0_2 = create_announced_chan_between_nodes_with_value(
+			&nodes, 0, 2, 100000, 10001, InitFeatures::known(), InitFeatures::known(),
+		);
+		nodes[0].node.handle_channel_update(&nodes[2].node.get_our_node_id(), &chan_0_2.1);
+		nodes[2].node.handle_channel_update(&nodes[0].node.get_our_node_id(), &chan_0_2.0);
+
+		let payment_amt = 20_000;
+		let (payment_hash, payment_secret) = nodes[1].node.create_inbound_payment(Some(payment_amt), 3600).unwrap();
+		let route_hints = vec![
+			nodes[1].node.get_phantom_route_hints(),
+			nodes[2].node.get_phantom_route_hints(),
+		];
+		let invoice = ::utils::create_phantom_invoice_with_description_hash::<
+			EnforcingSigner,
+			&test_utils::TestKeysInterface,
+		>(
+			Some(payment_amt), "Description hash phantom invoice".to_string(), payment_hash,
+			payment_secret, route_hints, &nodes[1].keys_manager, Currency::BitcoinTestnet,
+		)
+		.unwrap();
+
+		assert_eq!(invoice.amount_pico_btc(), Some(200_000));
+		assert_eq!(
+			invoice.min_final_cltv_expiry(),
+			MIN_FINAL_CLTV_EXPIRY as u64
+		);
+		assert_eq!(
+			invoice.description(),
+			InvoiceDescription::Hash(&crate::Sha256(Sha256::hash(
+				"Description hash phantom invoice".as_bytes()
+			)))
+		);
+	}
 }