Use time_provider in LSPS2 Service.

- is_past() on LSPSDateTime is changed so it receives a time_provider to get current time.
- is_expired_opening_fee_params() now receives a time_provider to pass to is_past()
- is_expired_opening_fee_params now does not depend on std being enabled.
- LSPS2 service now passes around the time_provider to be able to use wherever necessary.
- LSPS2 service now provides two new() methods:
1. a default new() that uses DefaultTimeProvider
2. a new_with_custom_time_provider() that expects a custom time_provider
Devices with no access to std will need to use the latter

Author: martinsaposnic

lightning-liquidity/src/lsps0/ser.rs

@@ -30,8 +30,7 @@ use lightning::util::ser::{LengthLimitedRead, LengthReadable, WithoutLength};
 
 use bitcoin::secp256k1::PublicKey;
 
-#[cfg(feature = "std")]
-use std::time::{SystemTime, UNIX_EPOCH};
+use crate::sync::Arc;
 
 use serde::de::{self, MapAccess, Visitor};
 use serde::ser::SerializeStruct;
@@ -205,12 +204,8 @@ impl LSPSDateTime {
 	}
 
 	/// Returns if the given time is in the past.
-	#[cfg(feature = "std")]
-	pub fn is_past(&self) -> bool {
-		let now_seconds_since_epoch = SystemTime::now()
-			.duration_since(UNIX_EPOCH)
-			.expect("system clock to be ahead of the unix epoch")
-			.as_secs();
+	pub fn is_past(&self, time_provider: Arc<dyn TimeProvider>) -> bool {
+		let now_seconds_since_epoch = time_provider.duration_since_epoch().as_secs();
 		let datetime_seconds_since_epoch =
 			self.0.timestamp().try_into().expect("expiration to be ahead of unix epoch");
 		now_seconds_since_epoch > datetime_seconds_since_epoch

lightning-liquidity/src/lsps2/msgs.rs

@@ -218,12 +218,32 @@ mod tests {
 	use super::*;
 
 	use crate::alloc::string::ToString;
+	use crate::lsps0::ser::TimeProvider;
 	use crate::lsps2::utils::is_valid_opening_fee_params;
-
+	use crate::sync::Arc;
+	use core::cell::RefCell;
 	use core::str::FromStr;
+	use core::time::Duration;
+
+	struct MockTimeProvider {
+		current_time: RefCell<Duration>,
+	}
+
+	impl MockTimeProvider {
+		fn new(seconds_since_epoch: u64) -> Self {
+			Self { current_time: RefCell::new(Duration::from_secs(seconds_since_epoch)) }
+		}
+	}
+
+	impl TimeProvider for MockTimeProvider {
+		fn duration_since_epoch(&self) -> Duration {
+			*self.current_time.borrow()
+		}
+	}
 
 	#[test]
 	fn into_opening_fee_params_produces_valid_promise() {
+		let time_provider = Arc::new(MockTimeProvider::new(1000));
 		let min_fee_msat = 100;
 		let proportional = 21;
 		let valid_until = LSPSDateTime::from_str("2035-05-20T08:30:45Z").unwrap();
@@ -254,11 +274,12 @@ mod tests {
 		assert_eq!(opening_fee_params.min_payment_size_msat, min_payment_size_msat);
 		assert_eq!(opening_fee_params.max_payment_size_msat, max_payment_size_msat);
 
-		assert!(is_valid_opening_fee_params(&opening_fee_params, &promise_secret));
+		assert!(is_valid_opening_fee_params(&opening_fee_params, &promise_secret, time_provider));
 	}
 
 	#[test]
 	fn changing_single_field_produced_invalid_params() {
+		let time_provider = Arc::new(MockTimeProvider::new(1000));
 		let min_fee_msat = 100;
 		let proportional = 21;
 		let valid_until = LSPSDateTime::from_str("2035-05-20T08:30:45Z").unwrap();
@@ -281,11 +302,12 @@ mod tests {
 
 		let mut opening_fee_params = raw.into_opening_fee_params(&promise_secret);
 		opening_fee_params.min_fee_msat = min_fee_msat + 1;
-		assert!(!is_valid_opening_fee_params(&opening_fee_params, &promise_secret));
+		assert!(!is_valid_opening_fee_params(&opening_fee_params, &promise_secret, time_provider));
 	}
 
 	#[test]
 	fn wrong_secret_produced_invalid_params() {
+		let time_provider = Arc::new(MockTimeProvider::new(1000));
 		let min_fee_msat = 100;
 		let proportional = 21;
 		let valid_until = LSPSDateTime::from_str("2035-05-20T08:30:45Z").unwrap();
@@ -308,13 +330,13 @@ mod tests {
 		let other_secret = [2u8; 32];
 
 		let opening_fee_params = raw.into_opening_fee_params(&promise_secret);
-		assert!(!is_valid_opening_fee_params(&opening_fee_params, &other_secret));
+		assert!(!is_valid_opening_fee_params(&opening_fee_params, &other_secret, time_provider));
 	}
 
 	#[test]
-	#[cfg(feature = "std")]
-	// TODO: We need to find a way to check expiry times in no-std builds.
 	fn expired_params_produces_invalid_params() {
+		// 70 years since epoch
+		let time_provider = Arc::new(MockTimeProvider::new(70 * 365 * 24 * 60 * 60)); // 1970 + 70 years
 		let min_fee_msat = 100;
 		let proportional = 21;
 		let valid_until = LSPSDateTime::from_str("2023-05-20T08:30:45Z").unwrap();
@@ -336,7 +358,7 @@ mod tests {
 		let promise_secret = [1u8; 32];
 
 		let opening_fee_params = raw.into_opening_fee_params(&promise_secret);
-		assert!(!is_valid_opening_fee_params(&opening_fee_params, &promise_secret));
+		assert!(!is_valid_opening_fee_params(&opening_fee_params, &promise_secret, time_provider));
 	}
 
 	#[test]

lightning-liquidity/src/lsps2/service.rs

@@ -16,8 +16,12 @@ use core::ops::Deref;
 use core::sync::atomic::{AtomicUsize, Ordering};
 
 use crate::events::EventQueue;
+
+#[cfg(feature = "time")]
+use crate::lsps0::ser::DefaultTimeProvider;
+
 use crate::lsps0::ser::{
-	LSPSMessage, LSPSProtocolMessageHandler, LSPSRequestId, LSPSResponseError,
+	LSPSMessage, LSPSProtocolMessageHandler, LSPSRequestId, LSPSResponseError, TimeProvider,
 	JSONRPC_INTERNAL_ERROR_ERROR_CODE, JSONRPC_INTERNAL_ERROR_ERROR_MESSAGE,
 	LSPS0_CLIENT_REJECTED_ERROR_CODE,
 };
@@ -400,18 +404,20 @@ struct OutboundJITChannel {
 	user_channel_id: u128,
 	opening_fee_params: LSPS2OpeningFeeParams,
 	payment_size_msat: Option<u64>,
+	time_provider: Arc<dyn TimeProvider>,
 }
 
 impl OutboundJITChannel {
 	fn new(
 		payment_size_msat: Option<u64>, opening_fee_params: LSPS2OpeningFeeParams,
-		user_channel_id: u128,
+		user_channel_id: u128, time_provider: Arc<dyn TimeProvider>,
 	) -> Self {
 		Self {
 			user_channel_id,
 			state: OutboundJITChannelState::new(),
 			opening_fee_params,
 			payment_size_msat,
+			time_provider,
 		}
 	}
 
@@ -451,7 +457,8 @@ impl OutboundJITChannel {
 	fn is_prunable(&self) -> bool {
 		// We deem an OutboundJITChannel prunable if our offer expired and we haven't intercepted
 		// any HTLCs initiating the flow yet.
-		let is_expired = is_expired_opening_fee_params(&self.opening_fee_params);
+		let is_expired =
+			is_expired_opening_fee_params(&self.opening_fee_params, self.time_provider.clone());
 		self.is_pending_initial_payment() && is_expired
 	}
 }
@@ -481,13 +488,16 @@ impl PeerState {
 		self.outbound_channels_by_intercept_scid.insert(intercept_scid, channel);
 	}
 
-	fn prune_expired_request_state(&mut self) {
+	fn prune_expired_request_state(&mut self, time_provider: Arc<dyn TimeProvider>) {
 		self.pending_requests.retain(|_, entry| {
 			match entry {
 				LSPS2Request::GetInfo(_) => false,
 				LSPS2Request::Buy(request) => {
 					// Prune any expired buy requests.
-					!is_expired_opening_fee_params(&request.opening_fee_params)
+					!is_expired_opening_fee_params(
+						&request.opening_fee_params,
+						time_provider.clone(),
+					)
 				},
 			}
 		});
@@ -566,16 +576,32 @@ where
 	peer_by_channel_id: RwLock<HashMap<ChannelId, PublicKey>>,
 	total_pending_requests: AtomicUsize,
 	config: LSPS2ServiceConfig,
+	time_provider: Arc<dyn TimeProvider>,
 }
 
 impl<CM: Deref> LSPS2ServiceHandler<CM>
 where
 	CM::Target: AChannelManager,
 {
+	#[cfg(feature = "time")]
 	/// Constructs a `LSPS2ServiceHandler`.
 	pub(crate) fn new(
 		pending_messages: Arc<MessageQueue>, pending_events: Arc<EventQueue>, channel_manager: CM,
 		config: LSPS2ServiceConfig,
+	) -> Self {
+		let time_provider = Arc::new(DefaultTimeProvider);
+		Self::new_with_custom_time_provider(
+			pending_messages,
+			pending_events,
+			channel_manager,
+			config,
+			time_provider,
+		)
+	}
+
+	pub(crate) fn new_with_custom_time_provider(
+		pending_messages: Arc<MessageQueue>, pending_events: Arc<EventQueue>, channel_manager: CM,
+		config: LSPS2ServiceConfig, time_provider: Arc<dyn TimeProvider>,
 	) -> Self {
 		Self {
 			pending_messages,
@@ -586,6 +612,7 @@ where
 			total_pending_requests: AtomicUsize::new(0),
 			channel_manager,
 			config,
+			time_provider,
 		}
 	}
 
@@ -737,6 +764,7 @@ where
 								buy_request.payment_size_msat,
 								buy_request.opening_fee_params,
 								user_channel_id,
+								self.time_provider.clone(),
 							);
 
 							peer_state_lock
@@ -1192,7 +1220,11 @@ where
 		}
 
 		// TODO: if payment_size_msat is specified, make sure our node has sufficient incoming liquidity from public network to receive it.
-		if !is_valid_opening_fee_params(&params.opening_fee_params, &self.config.promise_secret) {
+		if !is_valid_opening_fee_params(
+			&params.opening_fee_params,
+			&self.config.promise_secret,
+			self.time_provider.clone(),
+		) {
 			let response = LSPS2Response::BuyError(LSPSResponseError {
 				code: LSPS2_BUY_REQUEST_INVALID_OPENING_FEE_PARAMS_ERROR_CODE,
 				message: "valid_until is already past OR the promise did not match the provided parameters".to_string(),
@@ -1334,7 +1366,7 @@ where
 		let is_prunable =
 			if let Some(inner_state_lock) = outer_state_lock.get(&counterparty_node_id) {
 				let mut peer_state_lock = inner_state_lock.lock().unwrap();
-				peer_state_lock.prune_expired_request_state();
+				peer_state_lock.prune_expired_request_state(self.time_provider.clone());
 				peer_state_lock.is_prunable()
 			} else {
 				return;
@@ -1349,7 +1381,7 @@ where
 		let mut outer_state_lock = self.per_peer_state.write().unwrap();
 		outer_state_lock.retain(|_, inner_state_lock| {
 			let mut peer_state_lock = inner_state_lock.lock().unwrap();
-			peer_state_lock.prune_expired_request_state();
+			peer_state_lock.prune_expired_request_state(self.time_provider.clone());
 			peer_state_lock.is_prunable() == false
 		});
 	}

lightning-liquidity/src/lsps2/utils.rs

@@ -1,5 +1,8 @@
 //! Utilities for implementing the bLIP-52 / LSPS2 standard.
 
+use crate::sync::Arc;
+
+use crate::lsps0::ser::TimeProvider;
 use crate::lsps2::msgs::LSPS2OpeningFeeParams;
 use crate::utils;
 
@@ -10,8 +13,9 @@ use bitcoin::hashes::{Hash, HashEngine};
 /// Determines if the given parameters are valid given the secret used to generate the promise.
 pub fn is_valid_opening_fee_params(
 	fee_params: &LSPS2OpeningFeeParams, promise_secret: &[u8; 32],
+	time_provider: Arc<dyn TimeProvider>,
 ) -> bool {
-	if is_expired_opening_fee_params(fee_params) {
+	if is_expired_opening_fee_params(fee_params, time_provider) {
 		return false;
 	}
 	let mut hmac = HmacEngine::<Sha256>::new(promise_secret);
@@ -28,17 +32,10 @@ pub fn is_valid_opening_fee_params(
 }
 
 /// Determines if the given parameters are expired, or still valid.
-#[cfg_attr(not(feature = "std"), allow(unused_variables))]
-pub fn is_expired_opening_fee_params(fee_params: &LSPS2OpeningFeeParams) -> bool {
-	#[cfg(feature = "std")]
-	{
-		fee_params.valid_until.is_past()
-	}
-	#[cfg(not(feature = "std"))]
-	{
-		// TODO: We need to find a way to check expiry times in no-std builds.
-		false
-	}
+pub fn is_expired_opening_fee_params(
+	fee_params: &LSPS2OpeningFeeParams, time_provider: Arc<dyn TimeProvider>,
+) -> bool {
+	fee_params.valid_until.is_past(time_provider)
 }
 
 /// Computes the opening fee given a payment size and the fee parameters.

lightning-liquidity/tests/lsps2_integration_tests.rs

@@ -5,7 +5,7 @@ mod common;
 use common::{create_service_and_client_nodes, get_lsps_message, Node};
 
 use lightning_liquidity::events::LiquidityEvent;
-use lightning_liquidity::lsps0::ser::LSPSDateTime;
+use lightning_liquidity::lsps0::ser::{DefaultTimeProvider, LSPSDateTime, TimeProvider};
 use lightning_liquidity::lsps2::client::LSPS2ClientConfig;
 use lightning_liquidity::lsps2::event::{LSPS2ClientEvent, LSPS2ServiceEvent};
 use lightning_liquidity::lsps2::msgs::LSPS2RawOpeningFeeParams;
@@ -26,6 +26,7 @@ use bitcoin::secp256k1::{PublicKey, Secp256k1};
 use bitcoin::Network;
 
 use std::str::FromStr;
+use std::sync::Arc;
 use std::time::Duration;
 
 fn create_jit_invoice(
@@ -148,7 +149,7 @@ fn invoice_generation_flow() {
 		.liquidity_manager
 		.handle_custom_message(get_info_response, service_node_id)
 		.unwrap();
-
+	let time_provider: Arc<(dyn TimeProvider + 'static)> = Arc::new(DefaultTimeProvider);
 	let opening_params_event = client_node.liquidity_manager.next_event().unwrap();
 	let opening_fee_params = match opening_params_event {
 		LiquidityEvent::LSPS2Client(LSPS2ClientEvent::OpeningParametersReady {
@@ -159,7 +160,11 @@ fn invoice_generation_flow() {
 			assert_eq!(request_id, get_info_request_id);
 			assert_eq!(counterparty_node_id, service_node_id);
 			let opening_fee_params = opening_fee_params_menu.first().unwrap().clone();
-			assert!(is_valid_opening_fee_params(&opening_fee_params, &promise_secret));
+			assert!(is_valid_opening_fee_params(
+				&opening_fee_params,
+				&promise_secret,
+				time_provider
+			));
 			opening_fee_params
 		},
 		_ => panic!("Unexpected event"),