Include invreq in payment onion when retrying async payments

While in the last commit we began including invoice requests in async payment
onions on initial send, further work is needed to include them on retry. Here
we begin storing invreqs in our retry data, and pass them along for inclusion
in the onion on payment retry.

Per <lightning/bolts#1149>, when paying a static
invoice we need to include our original invoice request in the HTLC onion since
the recipient wouldn't have received it previously.

Author: valentinewallace

lightning/src/ln/outbound_payment.rs

@@ -94,6 +94,7 @@ pub(crate) enum PendingOutboundPayment {
 		payment_secret: Option<PaymentSecret>,
 		payment_metadata: Option<Vec<u8>>,
 		keysend_preimage: Option<PaymentPreimage>,
+		invoice_request: Option<InvoiceRequest>,
 		custom_tlvs: Vec<(u64, Vec<u8>)>,
 		pending_amt_msat: u64,
 		/// Used to track the fee paid. Present iff the payment was serialized on 0.0.103+.
@@ -948,20 +949,36 @@ impl OutboundPayments {
 		};
 
 		let payment_params = Some(route_params.payment_params.clone());
-		let (retryable_payment, onion_session_privs) = self.create_pending_payment(
-			payment_hash, recipient_onion.clone(), keysend_preimage, &route, Some(retry_strategy),
-			payment_params, entropy_source, best_block_height
-		);
-		match self.pending_outbound_payments.lock().unwrap().entry(payment_id) {
+		macro_rules! create_pending_payment {
+			($invreq_opt: expr) => {
+				self.create_pending_payment(
+					payment_hash, recipient_onion.clone(), keysend_preimage, $invreq_opt, &route,
+					Some(retry_strategy), payment_params, entropy_source, best_block_height
+				)
+			}
+		}
+
+		let mut outbounds = self.pending_outbound_payments.lock().unwrap();
+		let onion_session_privs = match outbounds.entry(payment_id) {
 			hash_map::Entry::Occupied(entry) => match entry.get() {
-				PendingOutboundPayment::InvoiceReceived { .. }
-				| PendingOutboundPayment::StaticInvoiceReceived { .. } => {
+				PendingOutboundPayment::InvoiceReceived { .. } => {
+					let (retryable_payment, onion_session_privs) = create_pending_payment!(None);
 					*entry.into_mut() = retryable_payment;
+					onion_session_privs
+				},
+				PendingOutboundPayment::StaticInvoiceReceived { .. } => {
+					let invreq = if let PendingOutboundPayment::StaticInvoiceReceived { invoice_request, .. } = entry.remove() {
+						invoice_request
+					} else { unreachable!() };
+					let (retryable_payment, onion_session_privs) = create_pending_payment!(Some(invreq));
+					outbounds.insert(payment_id, retryable_payment);
+					onion_session_privs
 				},
 				_ => return Err(Bolt12PaymentError::DuplicateInvoice),
 			},
 			hash_map::Entry::Vacant(_) => return Err(Bolt12PaymentError::UnexpectedInvoice),
-		}
+		};
+		core::mem::drop(outbounds);
 
 		let result = self.pay_route_internal(
 			&route, payment_hash, &recipient_onion, keysend_preimage, invoice_request, payment_id,
@@ -1324,14 +1341,14 @@ impl OutboundPayments {
 				}
 			}
 		}
-		let (total_msat, recipient_onion, keysend_preimage, onion_session_privs) = {
+		let (total_msat, recipient_onion, keysend_preimage, onion_session_privs, invoice_request) = {
 			let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 			match outbounds.entry(payment_id) {
 				hash_map::Entry::Occupied(mut payment) => {
 					match payment.get() {
 						PendingOutboundPayment::Retryable {
 							total_msat, keysend_preimage, payment_secret, payment_metadata,
-							custom_tlvs, pending_amt_msat, ..
+							custom_tlvs, pending_amt_msat, invoice_request, ..
 						} => {
 							const RETRY_OVERFLOW_PERCENTAGE: u64 = 10;
 							let retry_amt_msat = route.get_total_amount();
@@ -1354,6 +1371,7 @@ impl OutboundPayments {
 								custom_tlvs: custom_tlvs.clone(),
 							};
 							let keysend_preimage = *keysend_preimage;
+							let invoice_request = invoice_request.clone();
 
 							let mut onion_session_privs = Vec::with_capacity(route.paths.len());
 							for _ in 0..route.paths.len() {
@@ -1366,7 +1384,7 @@ impl OutboundPayments {
 
 							payment.get_mut().increment_attempts();
 
-							(total_msat, recipient_onion, keysend_preimage, onion_session_privs)
+							(total_msat, recipient_onion, keysend_preimage, onion_session_privs, invoice_request)
 						},
 						PendingOutboundPayment::Legacy { .. } => {
 							log_error!(logger, "Unable to retry payments that were initially sent on LDK versions prior to 0.0.102");
@@ -1404,8 +1422,8 @@ impl OutboundPayments {
 			}
 		};
 		let res = self.pay_route_internal(&route, payment_hash, &recipient_onion, keysend_preimage,
-			None, payment_id, Some(total_msat), onion_session_privs, node_signer, best_block_height,
-			&send_payment_along_path);
+			invoice_request.as_ref(), payment_id, Some(total_msat), onion_session_privs, node_signer,
+			best_block_height, &send_payment_along_path);
 		log_info!(logger, "Result retrying payment id {}: {:?}", &payment_id, res);
 		if let Err(e) = res {
 			self.handle_pay_route_err(e, payment_id, payment_hash, route, route_params, router, first_hops, inflight_htlcs, entropy_source, node_signer, best_block_height, logger, pending_events, send_payment_along_path);
@@ -1557,7 +1575,7 @@ impl OutboundPayments {
 			hash_map::Entry::Occupied(_) => Err(PaymentSendFailure::DuplicatePayment),
 			hash_map::Entry::Vacant(entry) => {
 				let (payment, onion_session_privs) = self.create_pending_payment(
-					payment_hash, recipient_onion, keysend_preimage, route, retry_strategy,
+					payment_hash, recipient_onion, keysend_preimage, None, route, retry_strategy,
 					payment_params, entropy_source, best_block_height
 				);
 				entry.insert(payment);
@@ -1568,8 +1586,9 @@ impl OutboundPayments {
 
 	fn create_pending_payment<ES: Deref>(
 		&self, payment_hash: PaymentHash, recipient_onion: RecipientOnionFields,
-		keysend_preimage: Option<PaymentPreimage>, route: &Route, retry_strategy: Option<Retry>,
-		payment_params: Option<PaymentParameters>, entropy_source: &ES, best_block_height: u32
+		keysend_preimage: Option<PaymentPreimage>, invoice_request: Option<InvoiceRequest>,
+		route: &Route, retry_strategy: Option<Retry>, payment_params: Option<PaymentParameters>,
+		entropy_source: &ES, best_block_height: u32
 	) -> (PendingOutboundPayment, Vec<[u8; 32]>)
 	where
 		ES::Target: EntropySource,
@@ -1590,6 +1609,7 @@ impl OutboundPayments {
 			payment_secret: recipient_onion.payment_secret,
 			payment_metadata: recipient_onion.payment_metadata,
 			keysend_preimage,
+			invoice_request,
 			custom_tlvs: recipient_onion.custom_tlvs,
 			starting_block_height: best_block_height,
 			total_msat: route.get_total_amount(),
@@ -2151,6 +2171,7 @@ impl OutboundPayments {
 					payment_secret: None, // only used for retries, and we'll never retry on startup
 					payment_metadata: None, // only used for retries, and we'll never retry on startup
 					keysend_preimage: None, // only used for retries, and we'll never retry on startup
+					invoice_request: None, // only used for retries, and we'll never retry on startup
 					custom_tlvs: Vec::new(), // only used for retries, and we'll never retry on startup
 					pending_amt_msat: path_amt,
 					pending_fee_msat: Some(path_fee),
@@ -2237,6 +2258,7 @@ impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
 		(9, custom_tlvs, optional_vec),
 		(10, starting_block_height, required),
 		(11, remaining_max_total_routing_fee_msat, option),
+		(13, invoice_request, option),
 		(not_written, retry_strategy, (static_value, None)),
 		(not_written, attempts, (static_value, PaymentAttempts::new())),
 	},