Merge pull request #1972 from jkczyz/2023-01-bolt12-spec-updates
[rust-lightning] / lightning / src / ln / outbound_payment.rs
index d6770d5a127f473ab5a1d7e92c17145d9fa78c81..8867b2e96ae14c3e75bb960d5dd9fa97ed10d746 100644 (file)
@@ -9,12 +9,30 @@
 
 //! Utilities to send payments and manage outbound payment information.
 
-use crate::ln::{PaymentHash, PaymentSecret};
-use crate::ln::channelmanager::PaymentId;
+use bitcoin::hashes::Hash;
+use bitcoin::hashes::sha256::Hash as Sha256;
+use bitcoin::secp256k1::{self, Secp256k1, SecretKey};
+
+use crate::chain::keysinterface::{EntropySource, NodeSigner, Recipient};
+use crate::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
+use crate::ln::channelmanager::{ChannelDetails, HTLCSource, IDEMPOTENCY_TIMEOUT_TICKS, MIN_HTLC_RELAY_HOLDING_CELL_MILLIS, PaymentId};
 use crate::ln::msgs::DecodeError;
-use crate::routing::router::{RouteHop, RouteParameters, RoutePath};
+use crate::ln::onion_utils::HTLCFailReason;
+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;
+use crate::util::time::Time;
+#[cfg(all(not(feature = "no-std"), test))]
+use crate::util::time::tests::SinceEpoch;
+
+use core::cmp;
+use core::fmt::{self, Display, Formatter};
+use core::ops::Deref;
+use core::time::Duration;
+
 use crate::prelude::*;
+use crate::sync::Mutex;
 
 /// Stores the session_priv for each part of a payment that is still pending. For versions 0.0.102
 /// and later, also stores information for retrying the payment.
@@ -23,6 +41,9 @@ pub(crate) enum PendingOutboundPayment {
                session_privs: HashSet<[u8; 32]>,
        },
        Retryable {
+               retry_strategy: Retry,
+               attempts: PaymentAttempts,
+               route_params: Option<RouteParameters>,
                session_privs: HashSet<[u8; 32]>,
                payment_hash: PaymentHash,
                payment_secret: Option<PaymentSecret>,
@@ -48,7 +69,7 @@ pub(crate) enum PendingOutboundPayment {
        /// `PaymentPathFailed` events with `all_paths_failed` can be pending at once, confusing a
        /// downstream event handler as to when a payment has actually failed.
        ///
-       /// (1) https://github.com/lightningdevkit/rust-lightning/issues/1164
+       /// (1) <https://github.com/lightningdevkit/rust-lightning/issues/1164>
        Abandoned {
                session_privs: HashSet<[u8; 32]>,
                payment_hash: PaymentHash,
@@ -56,6 +77,22 @@ pub(crate) enum PendingOutboundPayment {
 }
 
 impl PendingOutboundPayment {
+       fn increment_attempts(&mut self) {
+               if let PendingOutboundPayment::Retryable { attempts, .. } = self {
+                       attempts.count += 1;
+               }
+       }
+       fn is_retryable_now(&self) -> bool {
+               if let PendingOutboundPayment::Retryable { retry_strategy, attempts, .. } = self {
+                       return retry_strategy.is_retryable_now(&attempts)
+               }
+               false
+       }
+       pub fn insert_previously_failed_scid(&mut self, scid: u64) {
+               if let PendingOutboundPayment::Retryable { route_params: Some(params), .. } = self {
+                       params.payment_params.previously_failed_channels.push(scid);
+               }
+       }
        pub(super) fn is_fulfilled(&self) -> bool {
                match self {
                        PendingOutboundPayment::Fulfilled { .. } => true,
@@ -68,14 +105,14 @@ impl PendingOutboundPayment {
                        _ => false,
                }
        }
-       pub(super) fn get_pending_fee_msat(&self) -> Option<u64> {
+       fn get_pending_fee_msat(&self) -> Option<u64> {
                match self {
                        PendingOutboundPayment::Retryable { pending_fee_msat, .. } => pending_fee_msat.clone(),
                        _ => None,
                }
        }
 
-       pub(super) fn payment_hash(&self) -> Option<PaymentHash> {
+       fn payment_hash(&self) -> Option<PaymentHash> {
                match self {
                        PendingOutboundPayment::Legacy { .. } => None,
                        PendingOutboundPayment::Retryable { payment_hash, .. } => Some(*payment_hash),
@@ -84,7 +121,7 @@ impl PendingOutboundPayment {
                }
        }
 
-       pub(super) fn mark_fulfilled(&mut self) {
+       fn mark_fulfilled(&mut self) {
                let mut session_privs = HashSet::new();
                core::mem::swap(&mut session_privs, match self {
                        PendingOutboundPayment::Legacy { session_privs } |
@@ -97,7 +134,7 @@ impl PendingOutboundPayment {
                *self = PendingOutboundPayment::Fulfilled { session_privs, payment_hash, timer_ticks_without_htlcs: 0 };
        }
 
-       pub(super) fn mark_abandoned(&mut self) -> Result<(), ()> {
+       fn mark_abandoned(&mut self) -> Result<(), ()> {
                let mut session_privs = HashSet::new();
                let our_payment_hash;
                core::mem::swap(&mut session_privs, match self {
@@ -115,7 +152,7 @@ impl PendingOutboundPayment {
        }
 
        /// panics if path is None and !self.is_fulfilled
-       pub(super) fn remove(&mut self, session_priv: &[u8; 32], path: Option<&Vec<RouteHop>>) -> bool {
+       fn remove(&mut self, session_priv: &[u8; 32], path: Option<&Vec<RouteHop>>) -> bool {
                let remove_res = match self {
                        PendingOutboundPayment::Legacy { session_privs } |
                                PendingOutboundPayment::Retryable { session_privs, .. } |
@@ -170,6 +207,88 @@ impl PendingOutboundPayment {
        }
 }
 
+/// Strategies available to retry payment path failures.
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+pub enum Retry {
+       /// Max number of attempts to retry payment.
+       ///
+       /// Note that this is the number of *path* failures, not full payment retries. For multi-path
+       /// payments, if this is less than the total number of paths, we will never even retry all of the
+       /// payment's paths.
+       Attempts(usize),
+       #[cfg(not(feature = "no-std"))]
+       /// Time elapsed before abandoning retries for a payment.
+       Timeout(core::time::Duration),
+}
+
+impl Retry {
+       pub(crate) fn is_retryable_now(&self, attempts: &PaymentAttempts) -> bool {
+               match (self, attempts) {
+                       (Retry::Attempts(max_retry_count), PaymentAttempts { count, .. }) => {
+                               max_retry_count > count
+                       },
+                       #[cfg(all(not(feature = "no-std"), not(test)))]
+                       (Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. }) =>
+                               *max_duration >= std::time::Instant::now().duration_since(*first_attempted_at),
+                       #[cfg(all(not(feature = "no-std"), test))]
+                       (Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. }) =>
+                               *max_duration >= SinceEpoch::now().duration_since(*first_attempted_at),
+               }
+       }
+}
+
+#[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
+/// be retried.
+pub(crate) struct PaymentAttemptsUsingTime<T: Time> {
+       /// This count will be incremented only after the result of the attempt is known. When it's 0,
+       /// it means the result of the first attempt is not known yet.
+       pub(crate) count: usize,
+       /// This field is only used when retry is `Retry::Timeout` which is only build with feature std
+       first_attempted_at: T
+}
+
+#[cfg(not(any(feature = "no-std", test)))]
+type ConfiguredTime = std::time::Instant;
+#[cfg(feature = "no-std")]
+type ConfiguredTime = crate::util::time::Eternity;
+#[cfg(all(not(feature = "no-std"), test))]
+type ConfiguredTime = SinceEpoch;
+
+impl<T: Time> PaymentAttemptsUsingTime<T> {
+       pub(crate) fn new() -> Self {
+               PaymentAttemptsUsingTime {
+                       count: 0,
+                       first_attempted_at: T::now()
+               }
+       }
+}
+
+impl<T: Time> Display for PaymentAttemptsUsingTime<T> {
+       fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
+               #[cfg(feature = "no-std")]
+               return write!(f, "attempts: {}", self.count);
+               #[cfg(not(feature = "no-std"))]
+               return write!(
+                       f,
+                       "attempts: {}, duration: {}s",
+                       self.count,
+                       T::now().duration_since(self.first_attempted_at).as_secs()
+               );
+       }
+}
+
 /// If a payment fails to send, it can be in one of several states. This enum is returned as the
 /// Err() type describing which state the payment is in, see the description of individual enum
 /// states for more.
@@ -248,6 +367,727 @@ pub enum PaymentSendFailure {
        },
 }
 
+pub(super) struct OutboundPayments {
+       pub(super) pending_outbound_payments: Mutex<HashMap<PaymentId, PendingOutboundPayment>>,
+}
+
+impl OutboundPayments {
+       pub(super) fn new() -> Self {
+               Self {
+                       pending_outbound_payments: Mutex::new(HashMap::new())
+               }
+       }
+
+       pub(super) fn send_payment<R: Deref, ES: Deref, NS: Deref, F>(
+               &self, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>, payment_id: PaymentId,
+               retry_strategy: Retry, 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>,
+       {
+               self.pay_internal(payment_id, Some((payment_hash, payment_secret, retry_strategy)),
+                       route_params, router, first_hops, inflight_htlcs, entropy_source, node_signer,
+                       best_block_height, &send_payment_along_path)
+                       .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
+       }
+
+       pub(super) fn send_payment_with_route<ES: Deref, NS: Deref, F>(
+               &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
+               payment_id: PaymentId, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
+               send_payment_along_path: F
+       ) -> Result<(), PaymentSendFailure>
+       where
+               ES::Target: EntropySource,
+               NS::Target: NodeSigner,
+               F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
+                  u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
+       {
+               let onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, route, Retry::Attempts(0), None, entropy_source, best_block_height)?;
+               self.pay_route_internal(route, payment_hash, payment_secret, None, payment_id, None,
+                       onion_session_privs, node_signer, best_block_height, &send_payment_along_path)
+                       .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
+       }
+
+       pub(super) fn send_spontaneous_payment<ES: Deref, NS: Deref, F>(
+               &self, route: &Route, payment_preimage: Option<PaymentPreimage>, payment_id: PaymentId,
+               entropy_source: &ES, node_signer: &NS, best_block_height: u32, send_payment_along_path: F
+       ) -> Result<PaymentHash, PaymentSendFailure>
+       where
+               ES::Target: EntropySource,
+               NS::Target: NodeSigner,
+               F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
+                  u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
+       {
+               let preimage = match payment_preimage {
+                       Some(p) => p,
+                       None => PaymentPreimage(entropy_source.get_secure_random_bytes()),
+               };
+               let payment_hash = PaymentHash(Sha256::hash(&preimage.0).into_inner());
+               let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, &route, Retry::Attempts(0), None, entropy_source, best_block_height)?;
+
+               match self.pay_route_internal(route, payment_hash, &None, Some(preimage), payment_id, None, onion_session_privs, node_signer, best_block_height, &send_payment_along_path) {
+                       Ok(()) => Ok(payment_hash),
+                       Err(e) => {
+                               self.remove_outbound_if_all_failed(payment_id, &e);
+                               Err(e)
+                       }
+               }
+       }
+
+       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()));
+                                                       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, None, 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,
+               initial_send_info: Option<(PaymentHash, &Option<PaymentSecret>, Retry)>,
+               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 = if let Some((payment_hash, payment_secret, retry_strategy)) = initial_send_info {
+                       let onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, &route, retry_strategy, Some(route_params.clone()), entropy_source, best_block_height)?;
+                       self.pay_route_internal(&route, payment_hash, payment_secret, None, payment_id, None, onion_session_privs, node_signer, best_block_height, send_payment_along_path)
+               } else {
+                       self.retry_payment_with_route(&route, payment_id, entropy_source, node_signer, best_block_height, send_payment_along_path)
+               };
+               match res {
+                       Err(PaymentSendFailure::AllFailedResendSafe(_)) => {
+                               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 }
+                               core::mem::drop(outbounds);
+                               self.pay_internal(payment_id, None, route_params, router, first_hops, inflight_htlcs, entropy_source, node_signer, best_block_height, send_payment_along_path)
+                       },
+                       Err(PaymentSendFailure::PartialFailure { failed_paths_retry: Some(retry), results, .. }) => {
+                               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 Err(PaymentSendFailure::PartialFailure { failed_paths_retry: Some(retry), results, payment_id }) }
+                               } else { return Err(PaymentSendFailure::PartialFailure { failed_paths_retry: Some(retry), results, payment_id }) }
+                               core::mem::drop(outbounds);
+
+                               // 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, None, retry, router, first_hops, inflight_htlcs, entropy_source, node_signer, best_block_height, send_payment_along_path);
+                               Ok(())
+                       },
+                       Err(PaymentSendFailure::PartialFailure { failed_paths_retry: None, .. }) => {
+                               // 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
+       ) -> Result<(), PaymentSendFailure>
+       where
+               ES::Target: EntropySource,
+               NS::Target: NodeSigner,
+               F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
+                  u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
+       {
+               const RETRY_OVERFLOW_PERCENTAGE: u64 = 10;
+               for path in route.paths.iter() {
+                       if path.len() == 0 {
+                               return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
+                                       err: "length-0 path in route".to_string()
+                               }))
+                       }
+               }
+
+               let mut onion_session_privs = Vec::with_capacity(route.paths.len());
+               for _ in 0..route.paths.len() {
+                       onion_session_privs.push(entropy_source.get_secure_random_bytes());
+               }
+
+               let (total_msat, payment_hash, payment_secret) = {
+                       let mut outbounds = self.pending_outbound_payments.lock().unwrap();
+                       match outbounds.get_mut(&payment_id) {
+                               Some(payment) => {
+                                       let res = match payment {
+                                               PendingOutboundPayment::Retryable {
+                                                       total_msat, payment_hash, payment_secret, pending_amt_msat, ..
+                                               } => {
+                                                       let retry_amt_msat: u64 = route.paths.iter().map(|path| path.last().unwrap().fee_msat).sum();
+                                                       if retry_amt_msat + *pending_amt_msat > *total_msat * (100 + RETRY_OVERFLOW_PERCENTAGE) / 100 {
+                                                               return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
+                                                                       err: format!("retry_amt_msat of {} will put pending_amt_msat (currently: {}) more than 10% over total_payment_amt_msat of {}", retry_amt_msat, pending_amt_msat, total_msat).to_string()
+                                                               }))
+                                                       }
+                                                       (*total_msat, *payment_hash, *payment_secret)
+                                               },
+                                               PendingOutboundPayment::Legacy { .. } => {
+                                                       return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
+                                                               err: "Unable to retry payments that were initially sent on LDK versions prior to 0.0.102".to_string()
+                                                       }))
+                                               },
+                                               PendingOutboundPayment::Fulfilled { .. } => {
+                                                       return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
+                                                               err: "Payment already completed".to_owned()
+                                                       }));
+                                               },
+                                               PendingOutboundPayment::Abandoned { .. } => {
+                                                       return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
+                                                               err: "Payment already abandoned (with some HTLCs still pending)".to_owned()
+                                                       }));
+                                               },
+                                       };
+                                       for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
+                                               assert!(payment.insert(*session_priv_bytes, path));
+                                       }
+                                       res
+                               },
+                               None =>
+                                       return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
+                                               err: format!("Payment with ID {} not found", log_bytes!(payment_id.0)),
+                                       })),
+                       }
+               };
+               self.pay_route_internal(route, payment_hash, &payment_secret, None, payment_id, Some(total_msat), onion_session_privs, node_signer, best_block_height, &send_payment_along_path)
+       }
+
+       pub(super) fn send_probe<ES: Deref, NS: Deref, F>(
+               &self, hops: Vec<RouteHop>, probing_cookie_secret: [u8; 32], entropy_source: &ES,
+               node_signer: &NS, best_block_height: u32, send_payment_along_path: F
+       ) -> Result<(PaymentHash, PaymentId), PaymentSendFailure>
+       where
+               ES::Target: EntropySource,
+               NS::Target: NodeSigner,
+               F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
+                  u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
+       {
+               let payment_id = PaymentId(entropy_source.get_secure_random_bytes());
+
+               let payment_hash = probing_cookie_from_id(&payment_id, probing_cookie_secret);
+
+               if hops.len() < 2 {
+                       return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
+                               err: "No need probing a path with less than two hops".to_string()
+                       }))
+               }
+
+               let route = Route { paths: vec![hops], payment_params: None };
+               let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, &route, Retry::Attempts(0), None, entropy_source, best_block_height)?;
+
+               match self.pay_route_internal(&route, payment_hash, &None, None, payment_id, None, onion_session_privs, node_signer, best_block_height, &send_payment_along_path) {
+                       Ok(()) => Ok((payment_hash, payment_id)),
+                       Err(e) => {
+                               self.remove_outbound_if_all_failed(payment_id, &e);
+                               Err(e)
+                       }
+               }
+       }
+
+       #[cfg(test)]
+       pub(super) fn test_add_new_pending_payment<ES: Deref>(
+               &self, payment_hash: PaymentHash, payment_secret: Option<PaymentSecret>, payment_id: PaymentId,
+               route: &Route, retry_strategy: Retry, entropy_source: &ES, best_block_height: u32
+       ) -> Result<Vec<[u8; 32]>, PaymentSendFailure> where ES::Target: EntropySource {
+               self.add_new_pending_payment(payment_hash, payment_secret, payment_id, route, retry_strategy, None, entropy_source, best_block_height)
+       }
+
+       pub(super) fn add_new_pending_payment<ES: Deref>(
+               &self, payment_hash: PaymentHash, payment_secret: Option<PaymentSecret>, payment_id: PaymentId,
+               route: &Route, retry_strategy: Retry, route_params: Option<RouteParameters>,
+               entropy_source: &ES, best_block_height: u32
+       ) -> Result<Vec<[u8; 32]>, PaymentSendFailure> where ES::Target: EntropySource {
+               let mut onion_session_privs = Vec::with_capacity(route.paths.len());
+               for _ in 0..route.paths.len() {
+                       onion_session_privs.push(entropy_source.get_secure_random_bytes());
+               }
+
+               let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
+               match pending_outbounds.entry(payment_id) {
+                       hash_map::Entry::Occupied(_) => Err(PaymentSendFailure::DuplicatePayment),
+                       hash_map::Entry::Vacant(entry) => {
+                               let payment = entry.insert(PendingOutboundPayment::Retryable {
+                                       retry_strategy,
+                                       attempts: PaymentAttempts::new(),
+                                       route_params,
+                                       session_privs: HashSet::new(),
+                                       pending_amt_msat: 0,
+                                       pending_fee_msat: Some(0),
+                                       payment_hash,
+                                       payment_secret,
+                                       starting_block_height: best_block_height,
+                                       total_msat: route.get_total_amount(),
+                               });
+
+                               for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
+                                       assert!(payment.insert(*session_priv_bytes, path));
+                               }
+
+                               Ok(onion_session_privs)
+                       },
+               }
+       }
+
+       fn pay_route_internal<NS: Deref, F>(
+               &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
+               keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
+               onion_session_privs: Vec<[u8; 32]>, node_signer: &NS, best_block_height: u32,
+               send_payment_along_path: &F
+       ) -> Result<(), PaymentSendFailure>
+       where
+               NS::Target: NodeSigner,
+               F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
+                  u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
+       {
+               if route.paths.len() < 1 {
+                       return Err(PaymentSendFailure::ParameterError(APIError::InvalidRoute{err: "There must be at least one path to send over"}));
+               }
+               if payment_secret.is_none() && route.paths.len() > 1 {
+                       return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError{err: "Payment secret is required for multi-path payments".to_string()}));
+               }
+               let mut total_value = 0;
+               let our_node_id = node_signer.get_node_id(Recipient::Node).unwrap(); // TODO no unwrap
+               let mut path_errs = Vec::with_capacity(route.paths.len());
+               'path_check: for path in route.paths.iter() {
+                       if path.len() < 1 || path.len() > 20 {
+                               path_errs.push(Err(APIError::InvalidRoute{err: "Path didn't go anywhere/had bogus size"}));
+                               continue 'path_check;
+                       }
+                       for (idx, hop) in path.iter().enumerate() {
+                               if idx != path.len() - 1 && hop.pubkey == our_node_id {
+                                       path_errs.push(Err(APIError::InvalidRoute{err: "Path went through us but wasn't a simple rebalance loop to us"}));
+                                       continue 'path_check;
+                               }
+                       }
+                       total_value += path.last().unwrap().fee_msat;
+                       path_errs.push(Ok(()));
+               }
+               if path_errs.iter().any(|e| e.is_err()) {
+                       return Err(PaymentSendFailure::PathParameterError(path_errs));
+               }
+               if let Some(amt_msat) = recv_value_msat {
+                       debug_assert!(amt_msat >= total_value);
+                       total_value = amt_msat;
+               }
+
+               let cur_height = best_block_height + 1;
+               let mut results = Vec::new();
+               debug_assert_eq!(route.paths.len(), onion_session_privs.len());
+               for (path, session_priv) in route.paths.iter().zip(onion_session_privs.into_iter()) {
+                       let mut path_res = send_payment_along_path(&path, &route.payment_params, &payment_hash, payment_secret, total_value, cur_height, payment_id, &keysend_preimage, session_priv);
+                       match path_res {
+                               Ok(_) => {},
+                               Err(APIError::MonitorUpdateInProgress) => {
+                                       // While a MonitorUpdateInProgress is an Err(_), the payment is still
+                                       // considered "in flight" and we shouldn't remove it from the
+                                       // PendingOutboundPayment set.
+                               },
+                               Err(_) => {
+                                       let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
+                                       if let Some(payment) = pending_outbounds.get_mut(&payment_id) {
+                                               let removed = payment.remove(&session_priv, Some(path));
+                                               debug_assert!(removed, "This can't happen as the payment has an entry for this path added by callers");
+                                       } else {
+                                               debug_assert!(false, "This can't happen as the payment was added by callers");
+                                               path_res = Err(APIError::APIMisuseError { err: "Internal error: payment disappeared during processing. Please report this bug!".to_owned() });
+                                       }
+                               }
+                       }
+                       results.push(path_res);
+               }
+               let mut has_ok = false;
+               let mut has_err = false;
+               let mut pending_amt_unsent = 0;
+               let mut max_unsent_cltv_delta = 0;
+               for (res, path) in results.iter().zip(route.paths.iter()) {
+                       if res.is_ok() { has_ok = true; }
+                       if res.is_err() { has_err = true; }
+                       if let &Err(APIError::MonitorUpdateInProgress) = res {
+                               // MonitorUpdateInProgress is inherently unsafe to retry, so we call it a
+                               // PartialFailure.
+                               has_err = true;
+                               has_ok = true;
+                       } else if res.is_err() {
+                               pending_amt_unsent += path.last().unwrap().fee_msat;
+                               max_unsent_cltv_delta = cmp::max(max_unsent_cltv_delta, path.last().unwrap().cltv_expiry_delta);
+                       }
+               }
+               if has_err && has_ok {
+                       Err(PaymentSendFailure::PartialFailure {
+                               results,
+                               payment_id,
+                               failed_paths_retry: if pending_amt_unsent != 0 {
+                                       if let Some(payment_params) = &route.payment_params {
+                                               Some(RouteParameters {
+                                                       payment_params: payment_params.clone(),
+                                                       final_value_msat: pending_amt_unsent,
+                                                       final_cltv_expiry_delta: max_unsent_cltv_delta,
+                                               })
+                                       } else { None }
+                               } else { None },
+                       })
+               } else if has_err {
+                       Err(PaymentSendFailure::AllFailedResendSafe(results.drain(..).map(|r| r.unwrap_err()).collect()))
+               } else {
+                       Ok(())
+               }
+       }
+
+       #[cfg(test)]
+       pub(super) fn test_send_payment_internal<NS: Deref, F>(
+               &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
+               keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
+               onion_session_privs: Vec<[u8; 32]>, node_signer: &NS, best_block_height: u32,
+               send_payment_along_path: F
+       ) -> Result<(), PaymentSendFailure>
+       where
+               NS::Target: NodeSigner,
+               F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
+                  u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
+       {
+               self.pay_route_internal(route, payment_hash, payment_secret, keysend_preimage, payment_id,
+                       recv_value_msat, onion_session_privs, node_signer, best_block_height,
+                       &send_payment_along_path)
+                       .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
+       }
+
+       // If we failed to send any paths, we should remove the new PaymentId from the
+       // `pending_outbound_payments` map, as the user isn't expected to `abandon_payment`.
+       fn remove_outbound_if_all_failed(&self, payment_id: PaymentId, err: &PaymentSendFailure) {
+               if let &PaymentSendFailure::AllFailedResendSafe(_) = err {
+                       let removed = self.pending_outbound_payments.lock().unwrap().remove(&payment_id).is_some();
+                       debug_assert!(removed, "We should always have a pending payment to remove here");
+               }
+       }
+
+       pub(super) fn claim_htlc<L: Deref>(
+               &self, payment_id: PaymentId, payment_preimage: PaymentPreimage, session_priv: SecretKey,
+               path: Vec<RouteHop>, from_onchain: bool, pending_events: &Mutex<Vec<events::Event>>, logger: &L
+       ) where L::Target: Logger {
+               let mut session_priv_bytes = [0; 32];
+               session_priv_bytes.copy_from_slice(&session_priv[..]);
+               let mut outbounds = self.pending_outbound_payments.lock().unwrap();
+               let mut pending_events = pending_events.lock().unwrap();
+               if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
+                       if !payment.get().is_fulfilled() {
+                               let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
+                               let fee_paid_msat = payment.get().get_pending_fee_msat();
+                               pending_events.push(
+                                       events::Event::PaymentSent {
+                                               payment_id: Some(payment_id),
+                                               payment_preimage,
+                                               payment_hash,
+                                               fee_paid_msat,
+                                       }
+                               );
+                               payment.get_mut().mark_fulfilled();
+                       }
+
+                       if from_onchain {
+                               // We currently immediately remove HTLCs which were fulfilled on-chain.
+                               // This could potentially lead to removing a pending payment too early,
+                               // with a reorg of one block causing us to re-add the fulfilled payment on
+                               // restart.
+                               // TODO: We should have a second monitor event that informs us of payments
+                               // irrevocably fulfilled.
+                               if payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
+                                       let payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0).into_inner()));
+                                       pending_events.push(
+                                               events::Event::PaymentPathSuccessful {
+                                                       payment_id,
+                                                       payment_hash,
+                                                       path,
+                                               }
+                                       );
+                               }
+                       }
+               } else {
+                       log_trace!(logger, "Received duplicative fulfill for HTLC with payment_preimage {}", log_bytes!(payment_preimage.0));
+               }
+       }
+
+       pub(super) fn finalize_claims(&self, sources: Vec<HTLCSource>, pending_events: &Mutex<Vec<events::Event>>) {
+               let mut outbounds = self.pending_outbound_payments.lock().unwrap();
+               let mut pending_events = pending_events.lock().unwrap();
+               for source in sources {
+                       if let HTLCSource::OutboundRoute { session_priv, payment_id, path, .. } = source {
+                               let mut session_priv_bytes = [0; 32];
+                               session_priv_bytes.copy_from_slice(&session_priv[..]);
+                               if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
+                                       assert!(payment.get().is_fulfilled());
+                                       if payment.get_mut().remove(&session_priv_bytes, None) {
+                                               pending_events.push(
+                                                       events::Event::PaymentPathSuccessful {
+                                                               payment_id,
+                                                               payment_hash: payment.get().payment_hash(),
+                                                               path,
+                                                       }
+                                               );
+                                       }
+                               }
+                       }
+               }
+       }
+
+       pub(super) fn remove_stale_resolved_payments(&self, pending_events: &Mutex<Vec<events::Event>>) {
+               // If an outbound payment was completed, and no pending HTLCs remain, we should remove it
+               // from the map. However, if we did that immediately when the last payment HTLC is claimed,
+               // this could race the user making a duplicate send_payment call and our idempotency
+               // guarantees would be violated. Instead, we wait a few timer ticks to do the actual
+               // removal. This should be more than sufficient to ensure the idempotency of any
+               // `send_payment` calls that were made at the same time the `PaymentSent` event was being
+               // processed.
+               let mut pending_outbound_payments = self.pending_outbound_payments.lock().unwrap();
+               let pending_events = pending_events.lock().unwrap();
+               pending_outbound_payments.retain(|payment_id, payment| {
+                       if let PendingOutboundPayment::Fulfilled { session_privs, timer_ticks_without_htlcs, .. } = payment {
+                               let mut no_remaining_entries = session_privs.is_empty();
+                               if no_remaining_entries {
+                                       for ev in pending_events.iter() {
+                                               match ev {
+                                                       events::Event::PaymentSent { payment_id: Some(ev_payment_id), .. } |
+                                                               events::Event::PaymentPathSuccessful { payment_id: ev_payment_id, .. } |
+                                                               events::Event::PaymentPathFailed { payment_id: Some(ev_payment_id), .. } => {
+                                                                       if payment_id == ev_payment_id {
+                                                                               no_remaining_entries = false;
+                                                                               break;
+                                                                       }
+                                                               },
+                                                       _ => {},
+                                               }
+                                       }
+                               }
+                               if no_remaining_entries {
+                                       *timer_ticks_without_htlcs += 1;
+                                       *timer_ticks_without_htlcs <= IDEMPOTENCY_TIMEOUT_TICKS
+                               } else {
+                                       *timer_ticks_without_htlcs = 0;
+                                       true
+                               }
+                       } else { true }
+               });
+       }
+
+       pub(super) fn fail_htlc<L: Deref>(
+               &self, source: &HTLCSource, payment_hash: &PaymentHash, onion_error: &HTLCFailReason,
+               path: &Vec<RouteHop>, session_priv: &SecretKey, payment_id: &PaymentId,
+               payment_params: &Option<PaymentParameters>, probing_cookie_secret: [u8; 32],
+               secp_ctx: &Secp256k1<secp256k1::All>, pending_events: &Mutex<Vec<events::Event>>, logger: &L
+       ) where L::Target: Logger {
+               #[cfg(test)]
+               let (network_update, short_channel_id, payment_retryable, onion_error_code, onion_error_data) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
+               #[cfg(not(test))]
+               let (network_update, short_channel_id, payment_retryable, _, _) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
+
+               let mut session_priv_bytes = [0; 32];
+               session_priv_bytes.copy_from_slice(&session_priv[..]);
+               let mut outbounds = self.pending_outbound_payments.lock().unwrap();
+               let mut all_paths_failed = false;
+               let mut full_failure_ev = None;
+               let mut pending_retry_ev = None;
+               let attempts_remaining = if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(*payment_id) {
+                       if !payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
+                               log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
+                               return
+                       }
+                       if payment.get().is_fulfilled() {
+                               log_trace!(logger, "Received failure of HTLC with payment_hash {} after payment completion", log_bytes!(payment_hash.0));
+                               return
+                       }
+                       let is_retryable_now = payment.get().is_retryable_now();
+                       if let Some(scid) = short_channel_id {
+                               payment.get_mut().insert_previously_failed_scid(scid);
+                       }
+                       if payment.get().remaining_parts() == 0 {
+                               all_paths_failed = true;
+                               if payment.get().abandoned() {
+                                       full_failure_ev = Some(events::Event::PaymentFailed {
+                                               payment_id: *payment_id,
+                                               payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
+                                       });
+                                       payment.remove();
+                               }
+                       }
+                       is_retryable_now
+               } else {
+                       log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
+                       return
+               };
+               core::mem::drop(outbounds);
+               let mut retry = if let Some(payment_params_data) = payment_params {
+                       let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
+                       Some(RouteParameters {
+                               payment_params: payment_params_data.clone(),
+                               final_value_msat: path_last_hop.fee_msat,
+                               final_cltv_expiry_delta: path_last_hop.cltv_expiry_delta,
+                       })
+               } else { None };
+               log_trace!(logger, "Failing outbound payment HTLC with payment_hash {}", log_bytes!(payment_hash.0));
+
+               let path_failure = {
+                       if payment_is_probe(payment_hash, &payment_id, probing_cookie_secret) {
+                               if !payment_retryable {
+                                       events::Event::ProbeSuccessful {
+                                               payment_id: *payment_id,
+                                               payment_hash: payment_hash.clone(),
+                                               path: path.clone(),
+                                       }
+                               } else {
+                                       events::Event::ProbeFailed {
+                                               payment_id: *payment_id,
+                                               payment_hash: payment_hash.clone(),
+                                               path: path.clone(),
+                                               short_channel_id,
+                                       }
+                               }
+                       } else {
+                               // TODO: If we decided to blame ourselves (or one of our channels) in
+                               // process_onion_failure we should close that channel as it implies our
+                               // next-hop is needlessly blaming us!
+                               if let Some(scid) = short_channel_id {
+                                       retry.as_mut().map(|r| r.payment_params.previously_failed_channels.push(scid));
+                               }
+                               if payment_retryable && attempts_remaining && retry.is_some() {
+                                       debug_assert!(full_failure_ev.is_none());
+                                       pending_retry_ev = Some(events::Event::PendingHTLCsForwardable {
+                                               time_forwardable: Duration::from_millis(MIN_HTLC_RELAY_HOLDING_CELL_MILLIS),
+                                       });
+                               }
+                               events::Event::PaymentPathFailed {
+                                       payment_id: Some(*payment_id),
+                                       payment_hash: payment_hash.clone(),
+                                       payment_failed_permanently: !payment_retryable,
+                                       network_update,
+                                       all_paths_failed,
+                                       path: path.clone(),
+                                       short_channel_id,
+                                       retry,
+                                       #[cfg(test)]
+                                       error_code: onion_error_code,
+                                       #[cfg(test)]
+                                       error_data: onion_error_data
+                               }
+                       }
+               };
+               let mut pending_events = pending_events.lock().unwrap();
+               pending_events.push(path_failure);
+               if let Some(ev) = full_failure_ev { pending_events.push(ev); }
+               if let Some(ev) = pending_retry_ev { pending_events.push(ev); }
+       }
+
+       pub(super) fn abandon_payment(&self, payment_id: PaymentId) -> Option<events::Event> {
+               let mut failed_ev = None;
+               let mut outbounds = self.pending_outbound_payments.lock().unwrap();
+               if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
+                       if let Ok(()) = payment.get_mut().mark_abandoned() {
+                               if payment.get().remaining_parts() == 0 {
+                                       failed_ev = Some(events::Event::PaymentFailed {
+                                               payment_id,
+                                               payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
+                                       });
+                                       payment.remove();
+                               }
+                       }
+               }
+               failed_ev
+       }
+
+       #[cfg(test)]
+       pub fn has_pending_payments(&self) -> bool {
+               !self.pending_outbound_payments.lock().unwrap().is_empty()
+       }
+
+       #[cfg(test)]
+       pub fn clear_pending_payments(&self) {
+               self.pending_outbound_payments.lock().unwrap().clear()
+       }
+}
+
+/// Returns whether a payment with the given [`PaymentHash`] and [`PaymentId`] is, in fact, a
+/// payment probe.
+pub(super) fn payment_is_probe(payment_hash: &PaymentHash, payment_id: &PaymentId,
+       probing_cookie_secret: [u8; 32]) -> bool
+{
+       let target_payment_hash = probing_cookie_from_id(payment_id, probing_cookie_secret);
+       target_payment_hash == *payment_hash
+}
+
+/// Returns the 'probing cookie' for the given [`PaymentId`].
+fn probing_cookie_from_id(payment_id: &PaymentId, probing_cookie_secret: [u8; 32]) -> PaymentHash {
+       let mut preimage = [0u8; 64];
+       preimage[..32].copy_from_slice(&probing_cookie_secret);
+       preimage[32..].copy_from_slice(&payment_id.0);
+       PaymentHash(Sha256::hash(&preimage).into_inner())
+}
+
 impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
        (0, Legacy) => {
                (0, session_privs, required),
@@ -261,8 +1101,11 @@ impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
                (0, session_privs, required),
                (1, pending_fee_msat, option),
                (2, payment_hash, required),
+               (not_written, retry_strategy, (static_value, Retry::Attempts(0))),
                (4, payment_secret, option),
+               (not_written, attempts, (static_value, PaymentAttempts::new())),
                (6, total_msat, required),
+               (not_written, route_params, (static_value, None)),
                (8, pending_amt_msat, required),
                (10, starting_block_height, required),
        },
@@ -271,3 +1114,99 @@ impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
                (2, payment_hash, required),
        },
 );
+
+#[cfg(test)]
+mod tests {
+       use bitcoin::blockdata::constants::genesis_block;
+       use bitcoin::network::constants::Network;
+       use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
+
+       use crate::ln::PaymentHash;
+       use crate::ln::channelmanager::{PaymentId, PaymentSendFailure};
+       use crate::ln::msgs::{ErrorAction, LightningError};
+       use crate::ln::outbound_payment::{OutboundPayments, Retry};
+       use crate::routing::gossip::NetworkGraph;
+       use crate::routing::router::{InFlightHtlcs, PaymentParameters, Route, RouteParameters};
+       use crate::sync::Arc;
+       use crate::util::errors::APIError;
+       use crate::util::test_utils;
+
+       #[test]
+       #[cfg(feature = "std")]
+       fn fails_paying_after_expiration() {
+               do_fails_paying_after_expiration(false);
+               do_fails_paying_after_expiration(true);
+       }
+       #[cfg(feature = "std")]
+       fn do_fails_paying_after_expiration(on_retry: bool) {
+               let outbound_payments = OutboundPayments::new();
+               let logger = test_utils::TestLogger::new();
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
+               let network_graph = Arc::new(NetworkGraph::new(genesis_hash, &logger));
+               let router = test_utils::TestRouter::new(network_graph);
+               let secp_ctx = Secp256k1::new();
+               let keys_manager = test_utils::TestKeysInterface::new(&[0; 32], Network::Testnet);
+
+               let past_expiry_time = std::time::SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() - 2;
+               let payment_params = PaymentParameters::from_node_id(
+                       PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()))
+                       .with_expiry_time(past_expiry_time);
+               let expired_route_params = RouteParameters {
+                       payment_params,
+                       final_value_msat: 0,
+                       final_cltv_expiry_delta: 0,
+               };
+               let err = if on_retry {
+                       outbound_payments.pay_internal(
+                               PaymentId([0; 32]), None, expired_route_params, &&router, vec![], InFlightHtlcs::new(),
+                               &&keys_manager, &&keys_manager, 0, &|_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
+               } else {
+                       outbound_payments.send_payment(
+                               PaymentHash([0; 32]), &None, PaymentId([0; 32]), Retry::Attempts(0), expired_route_params,
+                               &&router, vec![], InFlightHtlcs::new(), &&keys_manager, &&keys_manager, 0, |_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
+               };
+               if let PaymentSendFailure::ParameterError(APIError::APIMisuseError { err }) = err {
+                       assert!(err.contains("Invoice expired"));
+               } else { panic!("Unexpected error"); }
+       }
+
+       #[test]
+       fn find_route_error() {
+               do_find_route_error(false);
+               do_find_route_error(true);
+       }
+       fn do_find_route_error(on_retry: bool) {
+               let outbound_payments = OutboundPayments::new();
+               let logger = test_utils::TestLogger::new();
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
+               let network_graph = Arc::new(NetworkGraph::new(genesis_hash, &logger));
+               let router = test_utils::TestRouter::new(network_graph);
+               let secp_ctx = Secp256k1::new();
+               let keys_manager = test_utils::TestKeysInterface::new(&[0; 32], Network::Testnet);
+
+               router.expect_find_route(Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError }));
+
+               let payment_params = PaymentParameters::from_node_id(
+                       PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()));
+               let route_params = RouteParameters {
+                       payment_params,
+                       final_value_msat: 0,
+                       final_cltv_expiry_delta: 0,
+               };
+               let err = if on_retry {
+                       outbound_payments.add_new_pending_payment(PaymentHash([0; 32]), None, PaymentId([0; 32]),
+                       &Route { paths: vec![], payment_params: None }, Retry::Attempts(1), Some(route_params.clone()),
+                       &&keys_manager, 0).unwrap();
+                       outbound_payments.pay_internal(
+                               PaymentId([0; 32]), None, route_params, &&router, vec![], InFlightHtlcs::new(),
+                               &&keys_manager, &&keys_manager, 0, &|_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
+               } else {
+                       outbound_payments.send_payment(
+                               PaymentHash([0; 32]), &None, PaymentId([0; 32]), Retry::Attempts(0), route_params,
+                               &&router, vec![], InFlightHtlcs::new(), &&keys_manager, &&keys_manager, 0, |_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
+               };
+               if let PaymentSendFailure::ParameterError(APIError::APIMisuseError { err }) = err {
+                       assert!(err.contains("Failed to find a route"));
+               } else { panic!("Unexpected error"); }
+       }
+}