Retry HTLCs in process_pending_htlc_forwards

Author: valentinewallace

lightning/src/ln/channelmanager.rs

@@ -3250,6 +3250,12 @@ where
 			}
 		}
 
+		let best_block_height = self.best_block.read().unwrap().height();
+		self.pending_outbound_payments.check_retry_payments(&self.router, || self.list_usable_channels(),
+			|| self.compute_inflight_htlcs(), &self.entropy_source, &self.node_signer, best_block_height, &self.logger,
+			|path, payment_params, payment_hash, payment_secret, total_value, cur_height, payment_id, keysend_preimage, session_priv|
+			self.send_payment_along_path(path, payment_params, payment_hash, payment_secret, total_value, cur_height, payment_id, keysend_preimage, session_priv));
+
 		for (htlc_source, payment_hash, failure_reason, destination) in failed_forwards.drain(..) {
 			self.fail_htlc_backwards_internal(&htlc_source, &payment_hash, &failure_reason, destination);
 		}

lightning/src/ln/outbound_payment.rs

@@ -15,10 +15,10 @@ use bitcoin::secp256k1::{self, Secp256k1, SecretKey};
 
 use crate::chain::keysinterface::{EntropySource, NodeSigner, Recipient};
 use crate::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
-use crate::ln::channelmanager::{HTLCSource, IDEMPOTENCY_TIMEOUT_TICKS, MIN_HTLC_RELAY_HOLDING_CELL_MILLIS, PaymentId};
+use crate::ln::channelmanager::{ChannelDetails, HTLCSource, IDEMPOTENCY_TIMEOUT_TICKS, MIN_HTLC_RELAY_HOLDING_CELL_MILLIS, PaymentId};
 use crate::ln::msgs::DecodeError;
 use crate::ln::onion_utils::HTLCFailReason;
-use crate::routing::router::{PaymentParameters, Route, RouteHop, RouteParameters, RoutePath};
+use crate::routing::router::{InFlightHtlcs, PaymentParameters, Route, RouteHop, RouteParameters, RoutePath, Router};
 use crate::util::errors::APIError;
 use crate::util::events;
 use crate::util::logger::Logger;
@@ -237,6 +237,16 @@ impl Retry {
 	}
 }
 
+#[cfg(feature = "std")]
+pub(super) fn has_expired(route_params: &RouteParameters) -> bool {
+	if let Some(expiry_time) = route_params.payment_params.expiry_time {
+		if let Ok(elapsed) = std::time::SystemTime::UNIX_EPOCH.elapsed() {
+			return elapsed > core::time::Duration::from_secs(expiry_time)
+		}
+	}
+	false
+}
+
 pub(crate) type PaymentAttempts = PaymentAttemptsUsingTime<ConfiguredTime>;
 
 /// Storing minimal payment attempts information required for determining if a outbound payment can
@@ -411,6 +421,104 @@ impl OutboundPayments {
 		}
 	}
 
+	pub(super) fn check_retry_payments<R: Deref, ES: Deref, NS: Deref, SP, IH, FH, L: Deref>(
+		&self, router: &R, first_hops: FH, inflight_htlcs: IH, entropy_source: &ES, node_signer: &NS,
+		best_block_height: u32, logger: &L, send_payment_along_path: SP,
+	)
+	where
+		R::Target: Router,
+		ES::Target: EntropySource,
+		NS::Target: NodeSigner,
+		SP: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
+		   u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>,
+		IH: Fn() -> InFlightHtlcs,
+		FH: Fn() -> Vec<ChannelDetails>,
+		L::Target: Logger,
+	{
+		loop {
+			let mut outbounds = self.pending_outbound_payments.lock().unwrap();
+			let mut retry_id_route_params = None;
+			for (pmt_id, pmt) in outbounds.iter_mut() {
+				if pmt.is_retryable_now() {
+					if let PendingOutboundPayment::Retryable { pending_amt_msat, total_msat, route_params: Some(params), .. } = pmt {
+						if pending_amt_msat < total_msat {
+							retry_id_route_params = Some((*pmt_id, params.clone()));
+						}
+					}
+				}
+				if retry_id_route_params.is_some() { pmt.increment_attempts(); break }
+			}
+			if let Some((payment_id, route_params)) = retry_id_route_params {
+				core::mem::drop(outbounds);
+				if let Err(e) = self.pay_internal(payment_id, route_params, router, first_hops(), inflight_htlcs(), entropy_source, node_signer, best_block_height, &send_payment_along_path) {
+					log_trace!(logger, "Errored retrying payment: {:?}", e);
+				}
+			} else { break }
+		}
+	}
+
+	fn pay_internal<R: Deref, NS: Deref, ES: Deref, F>(
+		&self, payment_id: PaymentId, route_params: RouteParameters, router: &R,
+		first_hops: Vec<ChannelDetails>, inflight_htlcs: InFlightHtlcs, entropy_source: &ES,
+		node_signer: &NS, best_block_height: u32, send_payment_along_path: &F
+	) -> Result<(), PaymentSendFailure>
+	where
+		R::Target: Router,
+		ES::Target: EntropySource,
+		NS::Target: NodeSigner,
+		F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
+		   u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
+	{
+		#[cfg(feature = "std")] {
+			if has_expired(&route_params) {
+				return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
+					err: format!("Invoice expired for payment id {}", log_bytes!(payment_id.0)),
+				}))
+			}
+		}
+
+		let route = router.find_route(
+			&node_signer.get_node_id(Recipient::Node).unwrap(), &route_params,
+			Some(&first_hops.iter().collect::<Vec<_>>()), &inflight_htlcs
+		).map_err(|e| PaymentSendFailure::ParameterError(APIError::APIMisuseError {
+			err: format!("Failed to find a route for payment {}: {:?}", log_bytes!(payment_id.0), e), // TODO: add APIError::RouteNotFound
+		}))?;
+
+		let res = self.retry_payment_with_route(&route, payment_id, entropy_source, node_signer, best_block_height, send_payment_along_path);
+		match res {
+			Err(PaymentSendFailure::AllFailedResendSafe(_)) | Err(PaymentSendFailure::PartialFailure { .. }) => {
+				let mut outbounds = self.pending_outbound_payments.lock().unwrap();
+				if let Some(payment) = outbounds.get_mut(&payment_id) {
+					let retryable = payment.is_retryable_now();
+					if retryable {
+						payment.increment_attempts();
+					} else { return res }
+				} else { return res }
+			}
+			res => return res
+		}
+		match res {
+			Err(PaymentSendFailure::AllFailedResendSafe(_)) => {
+				self.pay_internal(payment_id, route_params, router, first_hops, inflight_htlcs, entropy_source, node_signer, best_block_height, send_payment_along_path)
+			},
+			Err(PaymentSendFailure::PartialFailure { failed_paths_retry, .. }) => {
+				if let Some(retry) = failed_paths_retry {
+					// Some paths were sent, even if we failed to send the full MPP value our recipient may
+					// misbehave and claim the funds, at which point we have to consider the payment sent, so
+					// return `Ok()` here, ignoring any retry errors.
+					let _ = self.pay_internal(payment_id, retry, router, first_hops, inflight_htlcs, entropy_source, node_signer, best_block_height, send_payment_along_path);
+					Ok(())
+				} else {
+					// This may happen if we send a payment and some paths fail, but only due to a temporary
+					// monitor failure or the like, implying they're really in-flight, but we haven't sent the
+					// initial HTLC-Add messages yet.
+					Ok(())
+				}
+			},
+			res => res,
+		}
+	}
+
 	pub(super) fn retry_payment_with_route<ES: Deref, NS: Deref, F>(
 		&self, route: &Route, payment_id: PaymentId, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 		send_payment_along_path: F