Add PaymentParameters to spontaneous send

Added optional PaymentParameters to the send method in
SpontaneousPayment. If the user provides payment params
the values will be overridden otherwise they remain the
same. Updated the ldk_node.udl with these changes.

Author: slanesuke

bindings/ldk_node.udl

@@ -135,7 +135,7 @@ interface Bolt12Payment {
 
 interface SpontaneousPayment {
 	[Throws=NodeError]
-	PaymentId send(u64 amount_msat, PublicKey node_id);
+	PaymentId send(u64 amount_msat, PublicKey node_id, PaymentParameters? payment_parameters);
 	[Throws=NodeError]
 	void send_probes(u64 amount_msat, PublicKey node_id);
 };

src/payment/spontaneous.rs

@@ -4,13 +4,13 @@ use crate::config::{Config, LDK_PAYMENT_RETRY_TIMEOUT};
 use crate::error::Error;
 use crate::logger::{log_error, log_info, FilesystemLogger, Logger};
 use crate::payment::store::{
-	PaymentDetails, PaymentDirection, PaymentKind, PaymentStatus, PaymentStore,
+	PaymentDetails, PaymentDirection, PaymentKind, PaymentParameters, PaymentStatus, PaymentStore,
 };
 use crate::types::{ChannelManager, KeysManager};
 
 use lightning::ln::channelmanager::{PaymentId, RecipientOnionFields, Retry, RetryableSendFailure};
 use lightning::ln::{PaymentHash, PaymentPreimage};
-use lightning::routing::router::{PaymentParameters, RouteParameters};
+use lightning::routing::router::{PaymentParameters as PaymentParams, RouteParameters};
 use lightning::sign::EntropySource;
 
 use bitcoin::secp256k1::PublicKey;
@@ -41,8 +41,12 @@ impl SpontaneousPayment {
 		Self { runtime, channel_manager, keys_manager, payment_store, config, logger }
 	}
 
-	/// Send a spontaneous, aka. "keysend", payment
-	pub fn send(&self, amount_msat: u64, node_id: PublicKey) -> Result<PaymentId, Error> {
+	/// Send a spontaneous, or "keysend", payment given an amount in millisatoshi, node ID, and optional [`PaymentParameters`].
+	///
+	/// [`PaymentParameters`]: PaymentParameters
+	pub fn send(
+		&self, amount_msat: u64, node_id: PublicKey, payment_parameters: Option<PaymentParameters>,
+	) -> Result<PaymentId, Error> {
 		let rt_lock = self.runtime.read().unwrap();
 		if rt_lock.is_none() {
 			return Err(Error::NotRunning);
@@ -61,10 +65,23 @@ impl SpontaneousPayment {
 			}
 		}
 
-		let route_params = RouteParameters::from_payment_params_and_value(
-			PaymentParameters::from_node_id(node_id, self.config.default_cltv_expiry_delta),
+		let mut route_params = RouteParameters::from_payment_params_and_value(
+			PaymentParams::from_node_id(node_id, self.config.default_cltv_expiry_delta),
 			amount_msat,
 		);
+
+		if let Some(payment_params) = payment_parameters {
+			payment_params
+				.expiry_time
+				.map(|expiry| route_params.payment_params.expiry_time = Some(expiry));
+			payment_params
+				.max_total_routing_fee_msat
+				.map(|fee| route_params.max_total_routing_fee_msat = Some(fee));
+			payment_params
+				.max_total_cltv_expiry_delta
+				.map(|delta| route_params.payment_params.max_total_cltv_expiry_delta = delta);
+		}
+
 		let recipient_fields = RecipientOnionFields::spontaneous_empty();
 
 		match self.channel_manager.send_spontaneous_payment_with_retry(

tests/common/mod.rs

@@ -695,7 +695,7 @@ pub(crate) fn do_channel_full_cycle<E: ElectrumApi>(
 	println!("\nA send_spontaneous_payment");
 	let keysend_amount_msat = 2500_000;
 	let keysend_payment_id =
-		node_a.spontaneous_payment().send(keysend_amount_msat, node_b.node_id()).unwrap();
+		node_a.spontaneous_payment().send(keysend_amount_msat, node_b.node_id(), None).unwrap();
 	expect_event!(node_a, PaymentSuccessful);
 	let received_keysend_amount = match node_b.wait_next_event() {
 		ref e @ Event::PaymentReceived { amount_msat, .. } => {