LSPS2: Add support for ongoing proportional fees

Author: aylagreystone

lightning-liquidity/src/lsps2/client.rs

@@ -214,6 +214,7 @@ where
 					request_id,
 					counterparty_node_id: *counterparty_node_id,
 					opening_fee_params_menu: result.opening_fee_params_menu,
+					ongoing_proportional: result.ongoing_proportional,
 				});
 			},
 			None => {

lightning-liquidity/src/lsps2/event.rs

@@ -38,6 +38,8 @@ pub enum LSPS2ClientEvent {
 		/// The menu of fee parameters the LSP is offering at this time.
 		/// You must select one of these if you wish to proceed.
 		opening_fee_params_menu: Vec<LSPS2OpeningFeeParams>,
+		/// A flag indicating whether the LSP will collect ongoing proportional fees after the initial channel is opened.
+		ongoing_proportional: bool,
 	},
 	/// Provides the necessary information to generate a payable invoice that then may be given to
 	/// the payer.

lightning-liquidity/src/lsps2/msgs.rs

@@ -115,6 +115,8 @@ pub struct LSPS2OpeningFeeParams {
 pub struct LSPS2GetInfoResponse {
 	/// A set of opening fee parameters.
 	pub opening_fee_params_menu: Vec<LSPS2OpeningFeeParams>,
+	/// A flag for whether ongoing proportional fees will be collected.
+	pub ongoing_proportional: bool,
 }
 
 /// A request to buy a JIT channel.
@@ -348,6 +350,7 @@ mod tests {
 		let max_client_to_self_delay = 128;
 		let min_payment_size_msat = 1;
 		let max_payment_size_msat = 100_000_000;
+		let ongoing_proportional = true;
 
 		let raw = LSPS2RawOpeningFeeParams {
 			min_fee_msat,
@@ -382,7 +385,7 @@ mod tests {
 		assert_eq!(buy_request_variable, serde_json::from_str(json_str).unwrap());
 
 		// Check we still deserialize correctly if payment_size_msat is 'null'.
-		let json_str = r#"{"opening_fee_params":{"max_client_to_self_delay":128,"max_payment_size_msat":"100000000","min_fee_msat":"100","min_lifetime":144,"min_payment_size_msat":"1","promise":"1134a5c51e3ba2e8f4259610d5e12c1bf4c50ddcd3f8af563e0a00d1fff41dea","proportional":21,"valid_until":"2023-05-20T08:30:45Z"},"payment_size_msat":null}"#;
+		let json_str = r#"{"opening_fee_params":{"max_client_to_self_delay":128,"max_payment_size_msat":"100000000","min_fee_msat":"100","min_lifetime":144,"min_payment_size_msat":"1","promise":"1134a5c51e3ba2e8f4259610d5e12c1bf4c50ddcd3f8af563e0a00d1fff41dea","proportional":21,"valid_until":"2023-05-20T08:30:45Z"},"ongoing_proportional":true,"payment_size_msat":null}"#;
 		assert_eq!(buy_request_variable, serde_json::from_str(json_str).unwrap());
 	}
 
@@ -411,7 +414,8 @@ mod tests {
 				"max_payment_size_msat": "1000000",
 				"promise": "abcdefghijklmnopqrstuvwxyz"
 			}
-			]
+			],
+			"ongoing_proportional": true
 		}"#;
 		let _get_info_response: LSPS2GetInfoResponse = serde_json::from_str(json_str).unwrap();
 
@@ -426,6 +430,7 @@ mod tests {
 				"max_payment_size_msat": "1000000",
 				"promise": "abcdefghijklmnopqrstuvwxyz"
 			},
+			"ongoing_proportional": true,
 			"payment_size_msat": "42000"
 		}"#;
 		let _buy_request: LSPS2BuyRequest = serde_json::from_str(json_str).unwrap();

lightning-liquidity/src/lsps2/service.rs

@@ -634,7 +634,7 @@ where
 	/// [`LSPS2ServiceEvent::GetInfo`]: crate::lsps2::event::LSPS2ServiceEvent::GetInfo
 	pub fn opening_fee_params_generated(
 		&self, counterparty_node_id: &PublicKey, request_id: LSPSRequestId,
-		opening_fee_params_menu: Vec<LSPS2RawOpeningFeeParams>,
+		opening_fee_params_menu: Vec<LSPS2RawOpeningFeeParams>, ongoing_proportional: bool,
 	) -> Result<(), APIError> {
 		let (result, response) = {
 			let outer_state_lock = self.per_peer_state.read().unwrap();
@@ -652,6 +652,7 @@ where
 										param.into_opening_fee_params(&self.config.promise_secret)
 									})
 									.collect(),
+								ongoing_proportional,
 							});
 							(Ok(()), Some(response))
 						},

lightning-liquidity/tests/lsps2_integration_tests.rs

@@ -154,11 +154,14 @@ fn invoice_generation_flow() {
 		max_payment_size_msat: 100_000_000,
 	};
 
+	let ongoing_proportional = true;
+
 	service_handler
 		.opening_fee_params_generated(
 			&client_node_id,
 			get_info_request_id.clone(),
 			vec![raw_opening_params],
+			ongoing_proportional,
 		)
 		.unwrap();
 	let get_info_response = get_lsps_message!(service_node, client_node_id);
@@ -174,9 +177,11 @@ fn invoice_generation_flow() {
 			request_id,
 			counterparty_node_id,
 			opening_fee_params_menu,
+			ongoing_proportional,
 		}) => {
 			assert_eq!(request_id, get_info_request_id);
 			assert_eq!(counterparty_node_id, service_node_id);
+			assert_eq!(ongoing_proportional, ongoing_proportional);
 			let opening_fee_params = opening_fee_params_menu.first().unwrap().clone();
 			assert!(is_valid_opening_fee_params(&opening_fee_params, &promise_secret));
 			opening_fee_params
@@ -282,11 +287,15 @@ fn channel_open_failed() {
 		min_payment_size_msat: 1,
 		max_payment_size_msat: 100_000_000,
 	};
+
+	let ongoing_proportional = true;
+
 	service_handler
 		.opening_fee_params_generated(
 			&client_node_id,
 			get_info_request_id.clone(),
 			vec![raw_opening_params],
+			ongoing_proportional,
 		)
 		.unwrap();
 
@@ -430,11 +439,14 @@ fn channel_open_abandoned() {
 		min_payment_size_msat: 1,
 		max_payment_size_msat: 100_000_000,
 	};
+	let ongoing_proportional = true;
+
 	service_handler
 		.opening_fee_params_generated(
 			&client_node_id,
 			get_info_request_id.clone(),
 			vec![raw_opening_params],
+			ongoing_proportional,
 		)
 		.unwrap();
 
@@ -584,9 +596,15 @@ fn max_total_requests_buy_rejected() {
 			min_payment_size_msat: 1,
 			max_payment_size_msat: 100_000_000,
 		};
+		let ongoing_proportional = true;
 
 		service_handler
-			.opening_fee_params_generated(&special_node_id, request_id, vec![raw_opening_params])
+			.opening_fee_params_generated(
+				&special_node_id,
+				request_id,
+				vec![raw_opening_params],
+				ongoing_proportional,
+			)
 			.unwrap();
 	} else {
 		panic!("Unexpected event");
@@ -713,11 +731,13 @@ fn invalid_token_flow() {
 			min_payment_size_msat: 1,
 			max_payment_size_msat: 100_000_000,
 		};
+		let ongoing_proportional = true;
 
 		let result = service_handler.opening_fee_params_generated(
 			&client_node_id,
 			request_id.clone(),
 			vec![raw_opening_params],
+			ongoing_proportional,
 		);
 
 		assert!(result.is_err(), "Request should have been removed from pending_requests");