Use `crate::prelude::*` rather than specific imports
[rust-lightning] / lightning / src / routing / router.rs
index 86c42841027b8320dee54ffc230cae3384d6bd0b..e8276712ee89504e002b619aa70544a147467840 100644 (file)
 //! The router finds paths within a [`NetworkGraph`] for a payment.
 
 use bitcoin::secp256k1::{PublicKey, Secp256k1, self};
-use bitcoin::hashes::Hash;
-use bitcoin::hashes::sha256::Hash as Sha256;
 
 use crate::blinded_path::{BlindedHop, BlindedPath};
 use crate::blinded_path::payment::{ForwardNode, ForwardTlvs, PaymentConstraints, PaymentRelay, ReceiveTlvs};
 use crate::ln::PaymentHash;
-use crate::ln::channelmanager::{ChannelDetails, PaymentId};
+use crate::ln::channelmanager::{ChannelDetails, PaymentId, MIN_FINAL_CLTV_EXPIRY_DELTA};
 use crate::ln::features::{BlindedHopFeatures, Bolt11InvoiceFeatures, Bolt12InvoiceFeatures, ChannelFeatures, NodeFeatures};
 use crate::ln::msgs::{DecodeError, ErrorAction, LightningError, MAX_VALUE_MSAT};
 use crate::offers::invoice::{BlindedPayInfo, Bolt12Invoice};
-use crate::onion_message::{DefaultMessageRouter, Destination, MessageRouter, OnionMessagePath};
+use crate::onion_message::messenger::{DefaultMessageRouter, Destination, MessageRouter, OnionMessagePath};
 use crate::routing::gossip::{DirectedChannelInfo, EffectiveCapacity, ReadOnlyNetworkGraph, NetworkGraph, NodeId, RoutingFees};
 use crate::routing::scoring::{ChannelUsage, LockableScore, ScoreLookUp};
 use crate::sign::EntropySource;
 use crate::util::ser::{Writeable, Readable, ReadableArgs, Writer};
 use crate::util::logger::{Level, Logger};
-use crate::util::chacha20::ChaCha20;
+use crate::crypto::chacha20::ChaCha20;
 
 use crate::io;
 use crate::prelude::*;
-use crate::sync::Mutex;
 use alloc::collections::BinaryHeap;
 use core::{cmp, fmt};
 use core::ops::Deref;
 
 /// A [`Router`] implemented using [`find_route`].
-pub struct DefaultRouter<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> where
+pub struct DefaultRouter<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, ES: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> where
        L::Target: Logger,
        S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,
+       ES::Target: EntropySource,
 {
        network_graph: G,
        logger: L,
-       random_seed_bytes: Mutex<[u8; 32]>,
+       entropy_source: ES,
        scorer: S,
        score_params: SP,
-       message_router: DefaultMessageRouter<G, L>,
+       message_router: DefaultMessageRouter<G, L, ES>,
 }
 
-impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> DefaultRouter<G, L, S, SP, Sc> where
+impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, ES: Deref + Clone, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> DefaultRouter<G, L, ES, S, SP, Sc> where
        L::Target: Logger,
        S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,
+       ES::Target: EntropySource,
 {
        /// Creates a new router.
-       pub fn new(network_graph: G, logger: L, random_seed_bytes: [u8; 32], scorer: S, score_params: SP) -> Self {
-               let random_seed_bytes = Mutex::new(random_seed_bytes);
-               let message_router = DefaultMessageRouter::new(network_graph.clone());
-               Self { network_graph, logger, random_seed_bytes, scorer, score_params, message_router }
+       pub fn new(network_graph: G, logger: L, entropy_source: ES, scorer: S, score_params: SP) -> Self {
+               let message_router = DefaultMessageRouter::new(network_graph.clone(), entropy_source.clone());
+               Self { network_graph, logger, entropy_source, scorer, score_params, message_router }
        }
 }
 
-impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> Router for DefaultRouter<G, L, S, SP, Sc> where
+impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, ES: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> Router for DefaultRouter<G, L, ES, S, SP, Sc> where
        L::Target: Logger,
        S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,
+       ES::Target: EntropySource,
 {
        fn find_route(
                &self,
@@ -71,11 +70,7 @@ impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized,
                first_hops: Option<&[&ChannelDetails]>,
                inflight_htlcs: InFlightHtlcs
        ) -> Result<Route, LightningError> {
-               let random_seed_bytes = {
-                       let mut locked_random_seed_bytes = self.random_seed_bytes.lock().unwrap();
-                       *locked_random_seed_bytes = Sha256::hash(&*locked_random_seed_bytes).to_byte_array();
-                       *locked_random_seed_bytes
-               };
+               let random_seed_bytes = self.entropy_source.get_secure_random_bytes();
                find_route(
                        payer, params, &self.network_graph, first_hops, &*self.logger,
                        &ScorerAccountingForInFlightHtlcs::new(self.scorer.read_lock(), &inflight_htlcs),
@@ -85,10 +80,10 @@ impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized,
        }
 
        fn create_blinded_payment_paths<
-               ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification
-       >(
+               T: secp256k1::Signing + secp256k1::Verification
+       > (
                &self, recipient: PublicKey, first_hops: Vec<ChannelDetails>, tlvs: ReceiveTlvs,
-               amount_msats: u64, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+               amount_msats: u64, secp_ctx: &Secp256k1<T>
        ) -> Result<Vec<(BlindedPayInfo, BlindedPath)>, ()> {
                // Limit the number of blinded paths that are computed.
                const MAX_PAYMENT_PATHS: usize = 3;
@@ -102,7 +97,7 @@ impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized,
                        .filter(|details| details.counterparty.features.supports_route_blinding())
                        .filter(|details| amount_msats <= details.inbound_capacity_msat)
                        .filter(|details| amount_msats >= details.inbound_htlc_minimum_msat.unwrap_or(0))
-                       .filter(|details| amount_msats <= details.inbound_htlc_maximum_msat.unwrap_or(0))
+                       .filter(|details| amount_msats <= details.inbound_htlc_maximum_msat.unwrap_or(u64::MAX))
                        .filter(|details| network_graph
                                        .node(&NodeId::from_pubkey(&details.counterparty.node_id))
                                        .map(|node_info| node_info.channels.len() >= MIN_PEER_CHANNELS)
@@ -114,19 +109,14 @@ impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized,
                                        None => return None,
                                };
                                let payment_relay: PaymentRelay = match details.counterparty.forwarding_info {
-                                       Some(forwarding_info) => forwarding_info.into(),
+                                       Some(forwarding_info) => match forwarding_info.try_into() {
+                                               Ok(payment_relay) => payment_relay,
+                                               Err(()) => return None,
+                                       },
                                        None => return None,
                                };
 
-                               // Avoid exposing esoteric CLTV expiry deltas
-                               let cltv_expiry_delta = match payment_relay.cltv_expiry_delta {
-                                       0..=40 => 40u32,
-                                       41..=80 => 80u32,
-                                       81..=144 => 144u32,
-                                       145..=216 => 216u32,
-                                       _ => return None,
-                               };
-
+                               let cltv_expiry_delta = payment_relay.cltv_expiry_delta as u32;
                                let payment_constraints = PaymentConstraints {
                                        max_cltv_expiry: tlvs.payment_constraints.max_cltv_expiry + cltv_expiry_delta,
                                        htlc_minimum_msat: details.inbound_htlc_minimum_msat.unwrap_or(0),
@@ -139,12 +129,13 @@ impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized,
                                                features: BlindedHopFeatures::empty(),
                                        },
                                        node_id: details.counterparty.node_id,
-                                       htlc_maximum_msat: details.inbound_htlc_maximum_msat.unwrap_or(0),
+                                       htlc_maximum_msat: details.inbound_htlc_maximum_msat.unwrap_or(u64::MAX),
                                })
                        })
                        .map(|forward_node| {
                                BlindedPath::new_for_payment(
-                                       &[forward_node], recipient, tlvs.clone(), u64::MAX, entropy_source, secp_ctx
+                                       &[forward_node], recipient, tlvs.clone(), u64::MAX, MIN_FINAL_CLTV_EXPIRY_DELTA,
+                                       &*self.entropy_source, secp_ctx
                                )
                        })
                        .take(MAX_PAYMENT_PATHS)
@@ -154,8 +145,9 @@ impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized,
                        Ok(paths) if !paths.is_empty() => Ok(paths),
                        _ => {
                                if network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient)) {
-                                       BlindedPath::one_hop_for_payment(recipient, tlvs, entropy_source, secp_ctx)
-                                               .map(|path| vec![path])
+                                       BlindedPath::one_hop_for_payment(
+                                               recipient, tlvs, MIN_FINAL_CLTV_EXPIRY_DELTA, &*self.entropy_source, secp_ctx
+                                       ).map(|path| vec![path])
                                } else {
                                        Err(())
                                }
@@ -164,9 +156,10 @@ impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized,
        }
 }
 
-impl< G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> MessageRouter for DefaultRouter<G, L, S, SP, Sc> where
+impl< G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, ES: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> MessageRouter for DefaultRouter<G, L, ES, S, SP, Sc> where
        L::Target: Logger,
        S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,
+       ES::Target: EntropySource,
 {
        fn find_path(
                &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
@@ -175,12 +168,11 @@ impl< G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized,
        }
 
        fn create_blinded_paths<
-               ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification
-       >(
-               &self, recipient: PublicKey, peers: Vec<PublicKey>, entropy_source: &ES,
-               secp_ctx: &Secp256k1<T>
+               T: secp256k1::Signing + secp256k1::Verification
+       > (
+               &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
        ) -> Result<Vec<BlindedPath>, ()> {
-               self.message_router.create_blinded_paths(recipient, peers, entropy_source, secp_ctx)
+               self.message_router.create_blinded_paths(recipient, peers, secp_ctx)
        }
 }
 
@@ -214,10 +206,10 @@ pub trait Router: MessageRouter {
        /// are assumed to be with the `recipient`'s peers. The payment secret and any constraints are
        /// given in `tlvs`.
        fn create_blinded_payment_paths<
-               ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification
-       >(
+               T: secp256k1::Signing + secp256k1::Verification
+       > (
                &self, recipient: PublicKey, first_hops: Vec<ChannelDetails>, tlvs: ReceiveTlvs,
-               amount_msats: u64, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+               amount_msats: u64, secp_ctx: &Secp256k1<T>
        ) -> Result<Vec<(BlindedPayInfo, BlindedPath)>, ()>;
 }
 
@@ -282,7 +274,7 @@ pub struct InFlightHtlcs(
 
 impl InFlightHtlcs {
        /// Constructs an empty `InFlightHtlcs`.
-       pub fn new() -> Self { InFlightHtlcs(HashMap::new()) }
+       pub fn new() -> Self { InFlightHtlcs(new_hash_map()) }
 
        /// Takes in a path with payer's node id and adds the path's details to `InFlightHtlcs`.
        pub fn process_path(&mut self, path: &Path, payer_node_id: PublicKey) {
@@ -513,20 +505,20 @@ impl Writeable for Route {
                write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
                (self.paths.len() as u64).write(writer)?;
                let mut blinded_tails = Vec::new();
-               for path in self.paths.iter() {
+               for (idx, path) in self.paths.iter().enumerate() {
                        (path.hops.len() as u8).write(writer)?;
-                       for (idx, hop) in path.hops.iter().enumerate() {
+                       for hop in path.hops.iter() {
                                hop.write(writer)?;
-                               if let Some(blinded_tail) = &path.blinded_tail {
-                                       if blinded_tails.is_empty() {
-                                               blinded_tails = Vec::with_capacity(path.hops.len());
-                                               for _ in 0..idx {
-                                                       blinded_tails.push(None);
-                                               }
-                                       }
-                                       blinded_tails.push(Some(blinded_tail));
-                               } else if !blinded_tails.is_empty() { blinded_tails.push(None); }
                        }
+                       if let Some(blinded_tail) = &path.blinded_tail {
+                               if blinded_tails.is_empty() {
+                                       blinded_tails = Vec::with_capacity(path.hops.len());
+                                       for _ in 0..idx {
+                                               blinded_tails.push(None);
+                                       }
+                               }
+                               blinded_tails.push(Some(blinded_tail));
+                       } else if !blinded_tails.is_empty() { blinded_tails.push(None); }
                }
                write_tlv_fields!(writer, {
                        // For compatibility with LDK versions prior to 0.0.117, we take the individual
@@ -534,7 +526,7 @@ impl Writeable for Route {
                        (1, self.route_params.as_ref().map(|p| &p.payment_params), option),
                        (2, blinded_tails, optional_vec),
                        (3, self.route_params.as_ref().map(|p| p.final_value_msat), option),
-                       (5, self.route_params.as_ref().map(|p| p.max_total_routing_fee_msat), option),
+                       (5, self.route_params.as_ref().and_then(|p| p.max_total_routing_fee_msat), option),
                });
                Ok(())
        }
@@ -711,6 +703,11 @@ pub struct PaymentParameters {
        /// payment to fail. Future attempts for the same payment shouldn't be relayed through any of
        /// these SCIDs.
        pub previously_failed_channels: Vec<u64>,
+
+       /// A list of indices corresponding to blinded paths in [`Payee::Blinded::route_hints`] which this
+       /// payment was previously attempted over and which caused the payment to fail. Future attempts
+       /// for the same payment shouldn't be relayed through any of these blinded paths.
+       pub previously_failed_blinded_path_idxs: Vec<u64>,
 }
 
 impl Writeable for PaymentParameters {
@@ -732,6 +729,7 @@ impl Writeable for PaymentParameters {
                        (7, self.previously_failed_channels, required_vec),
                        (8, *blinded_hints, optional_vec),
                        (9, self.payee.final_cltv_expiry_delta(), option),
+                       (11, self.previously_failed_blinded_path_idxs, required_vec),
                });
                Ok(())
        }
@@ -750,6 +748,7 @@ impl ReadableArgs<u32> for PaymentParameters {
                        (7, previously_failed_channels, optional_vec),
                        (8, blinded_route_hints, optional_vec),
                        (9, final_cltv_expiry_delta, (default_value, default_final_cltv_expiry_delta)),
+                       (11, previously_failed_blinded_path_idxs, optional_vec),
                });
                let blinded_route_hints = blinded_route_hints.unwrap_or(vec![]);
                let payee = if blinded_route_hints.len() != 0 {
@@ -773,6 +772,7 @@ impl ReadableArgs<u32> for PaymentParameters {
                        max_channel_saturation_power_of_half: _init_tlv_based_struct_field!(max_channel_saturation_power_of_half, (default_value, unused)),
                        expiry_time,
                        previously_failed_channels: previously_failed_channels.unwrap_or(Vec::new()),
+                       previously_failed_blinded_path_idxs: previously_failed_blinded_path_idxs.unwrap_or(Vec::new()),
                })
        }
 }
@@ -791,6 +791,7 @@ impl PaymentParameters {
                        max_path_count: DEFAULT_MAX_PATH_COUNT,
                        max_channel_saturation_power_of_half: DEFAULT_MAX_CHANNEL_SATURATION_POW_HALF,
                        previously_failed_channels: Vec::new(),
+                       previously_failed_blinded_path_idxs: Vec::new(),
                }
        }
 
@@ -829,6 +830,7 @@ impl PaymentParameters {
                        max_path_count: DEFAULT_MAX_PATH_COUNT,
                        max_channel_saturation_power_of_half: DEFAULT_MAX_CHANNEL_SATURATION_POW_HALF,
                        previously_failed_channels: Vec::new(),
+                       previously_failed_blinded_path_idxs: Vec::new(),
                }
        }
 
@@ -904,6 +906,19 @@ impl PaymentParameters {
        pub fn with_max_channel_saturation_power_of_half(self, max_channel_saturation_power_of_half: u8) -> Self {
                Self { max_channel_saturation_power_of_half, ..self }
        }
+
+       pub(crate) fn insert_previously_failed_blinded_path(&mut self, failed_blinded_tail: &BlindedTail) {
+               let mut found_blinded_tail = false;
+               for (idx, (_, path)) in self.payee.blinded_route_hints().iter().enumerate() {
+                       if failed_blinded_tail.hops == path.blinded_hops &&
+                               failed_blinded_tail.blinding_point == path.blinding_point
+                       {
+                               self.previously_failed_blinded_path_idxs.push(idx as u64);
+                               found_blinded_tail = true;
+                       }
+               }
+               debug_assert!(found_blinded_tail);
+       }
 }
 
 /// The recipient of a payment, differing based on whether they've hidden their identity with route
@@ -971,7 +986,7 @@ impl Payee {
                        _ => None,
                }
        }
-       fn blinded_route_hints(&self) -> &[(BlindedPayInfo, BlindedPath)] {
+       pub(crate) fn blinded_route_hints(&self) -> &[(BlindedPayInfo, BlindedPath)] {
                match self {
                        Self::Blinded { route_hints, .. } => &route_hints[..],
                        Self::Clear { .. } => &[]
@@ -1119,6 +1134,82 @@ const _GRAPH_NODE_SMALL: usize = 64 - core::mem::size_of::<RouteGraphNode>();
 #[cfg(any(ldk_bench, not(any(test, fuzzing))))]
 const _GRAPH_NODE_FIXED_SIZE: usize = core::mem::size_of::<RouteGraphNode>() - 64;
 
+/// A [`CandidateRouteHop::FirstHop`] entry.
+#[derive(Clone, Debug)]
+pub struct FirstHopCandidate<'a> {
+       /// Channel details of the first hop
+       ///
+       /// [`ChannelDetails::get_outbound_payment_scid`] MUST be `Some` (indicating the channel
+       /// has been funded and is able to pay), and accessor methods may panic otherwise.
+       ///
+       /// [`find_route`] validates this prior to constructing a [`CandidateRouteHop`].
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub details: &'a ChannelDetails,
+       /// The node id of the payer, which is also the source side of this candidate route hop.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub payer_node_id: &'a NodeId,
+}
+
+/// A [`CandidateRouteHop::PublicHop`] entry.
+#[derive(Clone, Debug)]
+pub struct PublicHopCandidate<'a> {
+       /// Information about the channel, including potentially its capacity and
+       /// direction-specific information.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub info: DirectedChannelInfo<'a>,
+       /// The short channel ID of the channel, i.e. the identifier by which we refer to this
+       /// channel.
+       pub short_channel_id: u64,
+}
+
+/// A [`CandidateRouteHop::PrivateHop`] entry.
+#[derive(Clone, Debug)]
+pub struct PrivateHopCandidate<'a> {
+       /// Information about the private hop communicated via BOLT 11.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub hint: &'a RouteHintHop,
+       /// Node id of the next hop in BOLT 11 route hint.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub target_node_id: &'a NodeId
+}
+
+/// A [`CandidateRouteHop::Blinded`] entry.
+#[derive(Clone, Debug)]
+pub struct BlindedPathCandidate<'a> {
+       /// Information about the blinded path including the fee, HTLC amount limits, and
+       /// cryptographic material required to build an HTLC through the given path.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub hint: &'a (BlindedPayInfo, BlindedPath),
+       /// Index of the hint in the original list of blinded hints.
+       ///
+       /// This is used to cheaply uniquely identify this blinded path, even though we don't have
+       /// a short channel ID for this hop.
+       hint_idx: usize,
+}
+
+/// A [`CandidateRouteHop::OneHopBlinded`] entry.
+#[derive(Clone, Debug)]
+pub struct OneHopBlindedPathCandidate<'a> {
+       /// Information about the blinded path including the fee, HTLC amount limits, and
+       /// cryptographic material required to build an HTLC terminating with the given path.
+       ///
+       /// Note that the [`BlindedPayInfo`] is ignored here.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub hint: &'a (BlindedPayInfo, BlindedPath),
+       /// Index of the hint in the original list of blinded hints.
+       ///
+       /// This is used to cheaply uniquely identify this blinded path, even though we don't have
+       /// a short channel ID for this hop.
+       hint_idx: usize,
+}
+
 /// A wrapper around the various hop representations.
 ///
 /// Can be used to examine the properties of a hop,
@@ -1126,36 +1217,14 @@ const _GRAPH_NODE_FIXED_SIZE: usize = core::mem::size_of::<RouteGraphNode>() - 6
 #[derive(Clone, Debug)]
 pub enum CandidateRouteHop<'a> {
        /// A hop from the payer, where the outbound liquidity is known.
-       FirstHop {
-               /// Channel details of the first hop
-               ///
-               /// [`ChannelDetails::get_outbound_payment_scid`] MUST be `Some` (indicating the channel
-               /// has been funded and is able to pay), and accessor methods may panic otherwise.
-               ///
-               /// [`find_route`] validates this prior to constructing a [`CandidateRouteHop`].
-               details: &'a ChannelDetails,
-               /// The node id of the payer, which is also the source side of this candidate route hop.
-               payer_node_id: &'a NodeId,
-       },
+       FirstHop(FirstHopCandidate<'a>),
        /// A hop found in the [`ReadOnlyNetworkGraph`].
-       PublicHop {
-               /// Information about the channel, including potentially its capacity and
-               /// direction-specific information.
-               info: DirectedChannelInfo<'a>,
-               /// The short channel ID of the channel, i.e. the identifier by which we refer to this
-               /// channel.
-               short_channel_id: u64,
-       },
+       PublicHop(PublicHopCandidate<'a>),
        /// A private hop communicated by the payee, generally via a BOLT 11 invoice.
        ///
        /// Because BOLT 11 route hints can take multiple hops to get to the destination, this may not
        /// terminate at the payee.
-       PrivateHop {
-               /// Information about the private hop communicated via BOLT 11.
-               hint: &'a RouteHintHop,
-               /// Node id of the next hop in BOLT 11 route hint.
-               target_node_id: &'a NodeId
-       },
+       PrivateHop(PrivateHopCandidate<'a>),
        /// A blinded path which starts with an introduction point and ultimately terminates with the
        /// payee.
        ///
@@ -1164,16 +1233,7 @@ pub enum CandidateRouteHop<'a> {
        ///
        /// Because blinded paths are "all or nothing", and we cannot use just one part of a blinded
        /// path, the full path is treated as a single [`CandidateRouteHop`].
-       Blinded {
-               /// Information about the blinded path including the fee, HTLC amount limits, and
-               /// cryptographic material required to build an HTLC through the given path.
-               hint: &'a (BlindedPayInfo, BlindedPath),
-               /// Index of the hint in the original list of blinded hints.
-               ///
-               /// This is used to cheaply uniquely identify this blinded path, even though we don't have
-               /// a short channel ID for this hop.
-               hint_idx: usize,
-       },
+       Blinded(BlindedPathCandidate<'a>),
        /// Similar to [`Self::Blinded`], but the path here only has one hop.
        ///
        /// While we treat this similarly to [`CandidateRouteHop::Blinded`] in many respects (e.g.
@@ -1185,18 +1245,7 @@ pub enum CandidateRouteHop<'a> {
        ///
        /// This primarily exists to track that we need to included a blinded path at the end of our
        /// [`Route`], even though it doesn't actually add an additional hop in the payment.
-       OneHopBlinded {
-               /// Information about the blinded path including the fee, HTLC amount limits, and
-               /// cryptographic material required to build an HTLC terminating with the given path.
-               ///
-               /// Note that the [`BlindedPayInfo`] is ignored here.
-               hint: &'a (BlindedPayInfo, BlindedPath),
-               /// Index of the hint in the original list of blinded hints.
-               ///
-               /// This is used to cheaply uniquely identify this blinded path, even though we don't have
-               /// a short channel ID for this hop.
-               hint_idx: usize,
-       },
+       OneHopBlinded(OneHopBlindedPathCandidate<'a>),
 }
 
 impl<'a> CandidateRouteHop<'a> {
@@ -1218,11 +1267,11 @@ impl<'a> CandidateRouteHop<'a> {
        #[inline]
        fn short_channel_id(&self) -> Option<u64> {
                match self {
-                       CandidateRouteHop::FirstHop { details, .. } => details.get_outbound_payment_scid(),
-                       CandidateRouteHop::PublicHop { short_channel_id, .. } => Some(*short_channel_id),
-                       CandidateRouteHop::PrivateHop { hint, .. } => Some(hint.short_channel_id),
-                       CandidateRouteHop::Blinded { .. } => None,
-                       CandidateRouteHop::OneHopBlinded { .. } => None,
+                       CandidateRouteHop::FirstHop(hop) => hop.details.get_outbound_payment_scid(),
+                       CandidateRouteHop::PublicHop(hop) => Some(hop.short_channel_id),
+                       CandidateRouteHop::PrivateHop(hop) => Some(hop.hint.short_channel_id),
+                       CandidateRouteHop::Blinded(_) => None,
+                       CandidateRouteHop::OneHopBlinded(_) => None,
                }
        }
 
@@ -1234,22 +1283,22 @@ impl<'a> CandidateRouteHop<'a> {
        #[inline]
        pub fn globally_unique_short_channel_id(&self) -> Option<u64> {
                match self {
-                       CandidateRouteHop::FirstHop { details, .. } => if details.is_public { details.short_channel_id } else { None },
-                       CandidateRouteHop::PublicHop { short_channel_id, .. } => Some(*short_channel_id),
-                       CandidateRouteHop::PrivateHop { .. } => None,
-                       CandidateRouteHop::Blinded { .. } => None,
-                       CandidateRouteHop::OneHopBlinded { .. } => None,
+                       CandidateRouteHop::FirstHop(hop) => if hop.details.is_public { hop.details.short_channel_id } else { None },
+                       CandidateRouteHop::PublicHop(hop) => Some(hop.short_channel_id),
+                       CandidateRouteHop::PrivateHop(_) => None,
+                       CandidateRouteHop::Blinded(_) => None,
+                       CandidateRouteHop::OneHopBlinded(_) => None,
                }
        }
 
        // NOTE: This may alloc memory so avoid calling it in a hot code path.
        fn features(&self) -> ChannelFeatures {
                match self {
-                       CandidateRouteHop::FirstHop { details, .. } => details.counterparty.features.to_context(),
-                       CandidateRouteHop::PublicHop { info, .. } => info.channel().features.clone(),
-                       CandidateRouteHop::PrivateHop { .. } => ChannelFeatures::empty(),
-                       CandidateRouteHop::Blinded { .. } => ChannelFeatures::empty(),
-                       CandidateRouteHop::OneHopBlinded { .. } => ChannelFeatures::empty(),
+                       CandidateRouteHop::FirstHop(hop) => hop.details.counterparty.features.to_context(),
+                       CandidateRouteHop::PublicHop(hop) => hop.info.channel().features.clone(),
+                       CandidateRouteHop::PrivateHop(_) => ChannelFeatures::empty(),
+                       CandidateRouteHop::Blinded(_) => ChannelFeatures::empty(),
+                       CandidateRouteHop::OneHopBlinded(_) => ChannelFeatures::empty(),
                }
        }
 
@@ -1261,11 +1310,11 @@ impl<'a> CandidateRouteHop<'a> {
        #[inline]
        pub fn cltv_expiry_delta(&self) -> u32 {
                match self {
-                       CandidateRouteHop::FirstHop { .. } => 0,
-                       CandidateRouteHop::PublicHop { info, .. } => info.direction().cltv_expiry_delta as u32,
-                       CandidateRouteHop::PrivateHop { hint, .. } => hint.cltv_expiry_delta as u32,
-                       CandidateRouteHop::Blinded { hint, .. } => hint.0.cltv_expiry_delta as u32,
-                       CandidateRouteHop::OneHopBlinded { .. } => 0,
+                       CandidateRouteHop::FirstHop(_) => 0,
+                       CandidateRouteHop::PublicHop(hop) => hop.info.direction().cltv_expiry_delta as u32,
+                       CandidateRouteHop::PrivateHop(hop) => hop.hint.cltv_expiry_delta as u32,
+                       CandidateRouteHop::Blinded(hop) => hop.hint.0.cltv_expiry_delta as u32,
+                       CandidateRouteHop::OneHopBlinded(_) => 0,
                }
        }
 
@@ -1273,10 +1322,10 @@ impl<'a> CandidateRouteHop<'a> {
        #[inline]
        pub fn htlc_minimum_msat(&self) -> u64 {
                match self {
-                       CandidateRouteHop::FirstHop { details, .. } => details.next_outbound_htlc_minimum_msat,
-                       CandidateRouteHop::PublicHop { info, .. } => info.direction().htlc_minimum_msat,
-                       CandidateRouteHop::PrivateHop { hint, .. } => hint.htlc_minimum_msat.unwrap_or(0),
-                       CandidateRouteHop::Blinded { hint, .. } => hint.0.htlc_minimum_msat,
+                       CandidateRouteHop::FirstHop(hop) => hop.details.next_outbound_htlc_minimum_msat,
+                       CandidateRouteHop::PublicHop(hop) => hop.info.direction().htlc_minimum_msat,
+                       CandidateRouteHop::PrivateHop(hop) => hop.hint.htlc_minimum_msat.unwrap_or(0),
+                       CandidateRouteHop::Blinded(hop) => hop.hint.0.htlc_minimum_msat,
                        CandidateRouteHop::OneHopBlinded { .. } => 0,
                }
        }
@@ -1285,18 +1334,18 @@ impl<'a> CandidateRouteHop<'a> {
        #[inline]
        pub fn fees(&self) -> RoutingFees {
                match self {
-                       CandidateRouteHop::FirstHop { .. } => RoutingFees {
+                       CandidateRouteHop::FirstHop(_) => RoutingFees {
                                base_msat: 0, proportional_millionths: 0,
                        },
-                       CandidateRouteHop::PublicHop { info, .. } => info.direction().fees,
-                       CandidateRouteHop::PrivateHop { hint, .. } => hint.fees,
-                       CandidateRouteHop::Blinded { hint, .. } => {
+                       CandidateRouteHop::PublicHop(hop) => hop.info.direction().fees,
+                       CandidateRouteHop::PrivateHop(hop) => hop.hint.fees,
+                       CandidateRouteHop::Blinded(hop) => {
                                RoutingFees {
-                                       base_msat: hint.0.fee_base_msat,
-                                       proportional_millionths: hint.0.fee_proportional_millionths
+                                       base_msat: hop.hint.0.fee_base_msat,
+                                       proportional_millionths: hop.hint.0.fee_proportional_millionths
                                }
                        },
-                       CandidateRouteHop::OneHopBlinded { .. } =>
+                       CandidateRouteHop::OneHopBlinded(_) =>
                                RoutingFees { base_msat: 0, proportional_millionths: 0 },
                }
        }
@@ -1307,17 +1356,17 @@ impl<'a> CandidateRouteHop<'a> {
        /// cached!
        fn effective_capacity(&self) -> EffectiveCapacity {
                match self {
-                       CandidateRouteHop::FirstHop { details, .. } => EffectiveCapacity::ExactLiquidity {
-                               liquidity_msat: details.next_outbound_htlc_limit_msat,
+                       CandidateRouteHop::FirstHop(hop) => EffectiveCapacity::ExactLiquidity {
+                               liquidity_msat: hop.details.next_outbound_htlc_limit_msat,
                        },
-                       CandidateRouteHop::PublicHop { info, .. } => info.effective_capacity(),
-                       CandidateRouteHop::PrivateHop { hint: RouteHintHop { htlc_maximum_msat: Some(max), .. }, .. } =>
+                       CandidateRouteHop::PublicHop(hop) => hop.info.effective_capacity(),
+                       CandidateRouteHop::PrivateHop(PrivateHopCandidate { hint: RouteHintHop { htlc_maximum_msat: Some(max), .. }, .. }) =>
                                EffectiveCapacity::HintMaxHTLC { amount_msat: *max },
-                       CandidateRouteHop::PrivateHop { hint: RouteHintHop { htlc_maximum_msat: None, .. }, .. } =>
+                       CandidateRouteHop::PrivateHop(PrivateHopCandidate { hint: RouteHintHop { htlc_maximum_msat: None, .. }, .. }) =>
                                EffectiveCapacity::Infinite,
-                       CandidateRouteHop::Blinded { hint, .. } =>
-                               EffectiveCapacity::HintMaxHTLC { amount_msat: hint.0.htlc_maximum_msat },
-                       CandidateRouteHop::OneHopBlinded { .. } => EffectiveCapacity::Infinite,
+                       CandidateRouteHop::Blinded(hop) =>
+                               EffectiveCapacity::HintMaxHTLC { amount_msat: hop.hint.0.htlc_maximum_msat },
+                       CandidateRouteHop::OneHopBlinded(_) => EffectiveCapacity::Infinite,
                }
        }
 
@@ -1327,19 +1376,28 @@ impl<'a> CandidateRouteHop<'a> {
        #[inline]
        fn id(&self) -> CandidateHopId {
                match self {
-                       CandidateRouteHop::Blinded { hint_idx, .. } => CandidateHopId::Blinded(*hint_idx),
-                       CandidateRouteHop::OneHopBlinded { hint_idx, .. } => CandidateHopId::Blinded(*hint_idx),
+                       CandidateRouteHop::Blinded(hop) => CandidateHopId::Blinded(hop.hint_idx),
+                       CandidateRouteHop::OneHopBlinded(hop) => CandidateHopId::Blinded(hop.hint_idx),
                        _ => CandidateHopId::Clear((self.short_channel_id().unwrap(), self.source() < self.target().unwrap())),
                }
        }
        fn blinded_path(&self) -> Option<&'a BlindedPath> {
                match self {
-                       CandidateRouteHop::Blinded { hint, .. } | CandidateRouteHop::OneHopBlinded { hint, .. } => {
+                       CandidateRouteHop::Blinded(BlindedPathCandidate { hint, .. }) | CandidateRouteHop::OneHopBlinded(OneHopBlindedPathCandidate { hint, .. }) => {
                                Some(&hint.1)
                        },
                        _ => None,
                }
        }
+       fn blinded_hint_idx(&self) -> Option<usize> {
+               match self {
+                       Self::Blinded(BlindedPathCandidate { hint_idx, .. }) |
+                       Self::OneHopBlinded(OneHopBlindedPathCandidate { hint_idx, .. }) => {
+                               Some(*hint_idx)
+                       },
+                       _ => None,
+               }
+       }
        /// Returns the source node id of current hop.
        ///
        /// Source node id refers to the node forwarding the HTLC through this hop.
@@ -1348,11 +1406,11 @@ impl<'a> CandidateRouteHop<'a> {
        #[inline]
        pub fn source(&self) -> NodeId {
                match self {
-                       CandidateRouteHop::FirstHop { payer_node_id, .. } => **payer_node_id,
-                       CandidateRouteHop::PublicHop { info, .. } => *info.source(),
-                       CandidateRouteHop::PrivateHop { hint, .. } => hint.src_node_id.into(),
-                       CandidateRouteHop::Blinded { hint, .. } => hint.1.introduction_node_id.into(),
-                       CandidateRouteHop::OneHopBlinded { hint, .. } => hint.1.introduction_node_id.into(),
+                       CandidateRouteHop::FirstHop(hop) => *hop.payer_node_id,
+                       CandidateRouteHop::PublicHop(hop) => *hop.info.source(),
+                       CandidateRouteHop::PrivateHop(hop) => hop.hint.src_node_id.into(),
+                       CandidateRouteHop::Blinded(hop) => hop.hint.1.introduction_node_id.into(),
+                       CandidateRouteHop::OneHopBlinded(hop) => hop.hint.1.introduction_node_id.into(),
                }
        }
        /// Returns the target node id of this hop, if known.
@@ -1367,11 +1425,11 @@ impl<'a> CandidateRouteHop<'a> {
        #[inline]
        pub fn target(&self) -> Option<NodeId> {
                match self {
-                       CandidateRouteHop::FirstHop { details, .. } => Some(details.counterparty.node_id.into()),
-                       CandidateRouteHop::PublicHop { info, .. } => Some(*info.target()),
-                       CandidateRouteHop::PrivateHop { target_node_id, .. } => Some(**target_node_id),
-                       CandidateRouteHop::Blinded { .. } => None,
-                       CandidateRouteHop::OneHopBlinded { .. } => None,
+                       CandidateRouteHop::FirstHop(hop) => Some(hop.details.counterparty.node_id.into()),
+                       CandidateRouteHop::PublicHop(hop) => Some(*hop.info.target()),
+                       CandidateRouteHop::PrivateHop(hop) => Some(*hop.target_node_id),
+                       CandidateRouteHop::Blinded(_) => None,
+                       CandidateRouteHop::OneHopBlinded(_) => None,
                }
        }
 }
@@ -1666,17 +1724,17 @@ struct LoggedCandidateHop<'a>(&'a CandidateRouteHop<'a>);
 impl<'a> fmt::Display for LoggedCandidateHop<'a> {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
                match self.0 {
-                       CandidateRouteHop::Blinded { hint, .. } | CandidateRouteHop::OneHopBlinded { hint, .. } => {
+                       CandidateRouteHop::Blinded(BlindedPathCandidate { hint, .. }) | CandidateRouteHop::OneHopBlinded(OneHopBlindedPathCandidate { hint, .. }) => {
                                "blinded route hint with introduction node id ".fmt(f)?;
                                hint.1.introduction_node_id.fmt(f)?;
                                " and blinding point ".fmt(f)?;
                                hint.1.blinding_point.fmt(f)
                        },
-                       CandidateRouteHop::FirstHop { .. } => {
+                       CandidateRouteHop::FirstHop(_) => {
                                "first hop with SCID ".fmt(f)?;
                                self.0.short_channel_id().unwrap().fmt(f)
                        },
-                       CandidateRouteHop::PrivateHop { .. } => {
+                       CandidateRouteHop::PrivateHop(_) => {
                                "route hint with SCID ".fmt(f)?;
                                self.0.short_channel_id().unwrap().fmt(f)
                        },
@@ -1915,7 +1973,7 @@ where L::Target: Logger {
        // inserting first hops suggested by the caller as targets.
        // Our search will then attempt to reach them while traversing from the payee node.
        let mut first_hop_targets: HashMap<_, Vec<&ChannelDetails>> =
-               HashMap::with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 });
+               hash_map_with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 });
        if let Some(hops) = first_hops {
                for chan in hops {
                        if chan.get_outbound_payment_scid().is_none() {
@@ -1934,7 +1992,7 @@ where L::Target: Logger {
                }
        }
 
-       let mut private_hop_key_cache = HashMap::with_capacity(
+       let mut private_hop_key_cache = hash_map_with_capacity(
                payment_params.payee.unblinded_route_hints().iter().map(|path| path.0.len()).sum()
        );
 
@@ -1955,7 +2013,7 @@ where L::Target: Logger {
 
        // Map from node_id to information about the best current path to that node, including feerate
        // information.
-       let mut dist: HashMap<NodeId, PathBuildingHop> = HashMap::with_capacity(network_nodes.len());
+       let mut dist: HashMap<NodeId, PathBuildingHop> = hash_map_with_capacity(network_nodes.len());
 
        // During routing, if we ignore a path due to an htlc_minimum_msat limit, we set this,
        // indicating that we may wish to try again with a higher value, potentially paying to meet an
@@ -1996,7 +2054,7 @@ where L::Target: Logger {
        // is used. Hence, liquidity used in one direction will not offset any used in the opposite
        // direction.
        let mut used_liquidities: HashMap<CandidateHopId, u64> =
-               HashMap::with_capacity(network_nodes.len());
+               hash_map_with_capacity(network_nodes.len());
 
        // Keeping track of how much value we already collected across other paths. Helps to decide
        // when we want to stop looking for new paths.
@@ -2091,14 +2149,21 @@ where L::Target: Logger {
                                                 (amount_to_transfer_over_msat < $next_hops_path_htlc_minimum_msat &&
                                                  recommended_value_msat >= $next_hops_path_htlc_minimum_msat));
 
-                                       let payment_failed_on_this_channel = scid_opt.map_or(false,
-                                               |scid| payment_params.previously_failed_channels.contains(&scid));
+                                       let payment_failed_on_this_channel = match scid_opt {
+                                               Some(scid) => payment_params.previously_failed_channels.contains(&scid),
+                                               None => match $candidate.blinded_hint_idx() {
+                                                       Some(idx) => {
+                                                               payment_params.previously_failed_blinded_path_idxs.contains(&(idx as u64))
+                                                       },
+                                                       None => false,
+                                               },
+                                       };
 
                                        let (should_log_candidate, first_hop_details) = match $candidate {
-                                               CandidateRouteHop::FirstHop { details, .. } => (true, Some(details)),
-                                               CandidateRouteHop::PrivateHop { .. } => (true, None),
-                                               CandidateRouteHop::Blinded { .. } => (true, None),
-                                               CandidateRouteHop::OneHopBlinded { .. } => (true, None),
+                                               CandidateRouteHop::FirstHop(hop) => (true, Some(hop.details)),
+                                               CandidateRouteHop::PrivateHop(_) => (true, None),
+                                               CandidateRouteHop::Blinded(_) => (true, None),
+                                               CandidateRouteHop::OneHopBlinded(_) => (true, None),
                                                _ => (false, None),
                                        };
 
@@ -2365,9 +2430,9 @@ where L::Target: Logger {
                        if !skip_node {
                                if let Some(first_channels) = first_hop_targets.get(&$node_id) {
                                        for details in first_channels {
-                                               let candidate = CandidateRouteHop::FirstHop {
+                                               let candidate = CandidateRouteHop::FirstHop(FirstHopCandidate {
                                                        details, payer_node_id: &our_node_id,
-                                               };
+                                               });
                                                add_entry!(&candidate, fee_to_target_msat,
                                                        $next_hops_value_contribution,
                                                        next_hops_path_htlc_minimum_msat, next_hops_path_penalty_msat,
@@ -2388,10 +2453,10 @@ where L::Target: Logger {
                                                        if let Some((directed_channel, source)) = chan.as_directed_to(&$node_id) {
                                                                if first_hops.is_none() || *source != our_node_id {
                                                                        if directed_channel.direction().enabled {
-                                                                               let candidate = CandidateRouteHop::PublicHop {
+                                                                               let candidate = CandidateRouteHop::PublicHop(PublicHopCandidate {
                                                                                        info: directed_channel,
                                                                                        short_channel_id: *chan_id,
-                                                                               };
+                                                                               });
                                                                                add_entry!(&candidate,
                                                                                        fee_to_target_msat,
                                                                                        $next_hops_value_contribution,
@@ -2422,9 +2487,9 @@ where L::Target: Logger {
                // place where it could be added.
                payee_node_id_opt.map(|payee| first_hop_targets.get(&payee).map(|first_channels| {
                        for details in first_channels {
-                               let candidate = CandidateRouteHop::FirstHop {
+                               let candidate = CandidateRouteHop::FirstHop(FirstHopCandidate {
                                        details, payer_node_id: &our_node_id,
-                               };
+                               });
                                let added = add_entry!(&candidate, 0, path_value_msat,
                                                                        0, 0u64, 0, 0).is_some();
                                log_trace!(logger, "{} direct route to payee via {}",
@@ -2459,8 +2524,8 @@ where L::Target: Logger {
                                network_nodes.get(&intro_node_id).is_some();
                        if !have_intro_node_in_graph || our_node_id == intro_node_id { continue }
                        let candidate = if hint.1.blinded_hops.len() == 1 {
-                               CandidateRouteHop::OneHopBlinded { hint, hint_idx }
-                       } else { CandidateRouteHop::Blinded { hint, hint_idx } };
+                               CandidateRouteHop::OneHopBlinded(OneHopBlindedPathCandidate { hint, hint_idx })
+                       } else { CandidateRouteHop::Blinded(BlindedPathCandidate { hint, hint_idx }) };
                        let mut path_contribution_msat = path_value_msat;
                        if let Some(hop_used_msat) = add_entry!(&candidate,
                                0, path_contribution_msat, 0, 0_u64, 0, 0)
@@ -2471,9 +2536,9 @@ where L::Target: Logger {
                                sort_first_hop_channels(first_channels, &used_liquidities, recommended_value_msat,
                                        our_node_pubkey);
                                for details in first_channels {
-                                       let first_hop_candidate = CandidateRouteHop::FirstHop {
+                                       let first_hop_candidate = CandidateRouteHop::FirstHop(FirstHopCandidate {
                                                details, payer_node_id: &our_node_id,
-                                       };
+                                       });
                                        let blinded_path_fee = match compute_fees(path_contribution_msat, candidate.fees()) {
                                                Some(fee) => fee,
                                                None => continue
@@ -2512,9 +2577,9 @@ where L::Target: Logger {
                                let mut aggregate_path_contribution_msat = path_value_msat;
 
                                for (idx, (hop, prev_hop_id)) in hop_iter.zip(prev_hop_iter).enumerate() {
-                                       let target = private_hop_key_cache.get(&prev_hop_id).unwrap();
+                                       let target = private_hop_key_cache.get(prev_hop_id).unwrap();
 
-                                       if let Some(first_channels) = first_hop_targets.get(&target) {
+                                       if let Some(first_channels) = first_hop_targets.get(target) {
                                                if first_channels.iter().any(|d| d.outbound_scid_alias == Some(hop.short_channel_id)) {
                                                        log_trace!(logger, "Ignoring route hint with SCID {} (and any previous) due to it being a direct channel of ours.",
                                                                hop.short_channel_id);
@@ -2524,12 +2589,12 @@ where L::Target: Logger {
 
                                        let candidate = network_channels
                                                .get(&hop.short_channel_id)
-                                               .and_then(|channel| channel.as_directed_to(&target))
-                                               .map(|(info, _)| CandidateRouteHop::PublicHop {
+                                               .and_then(|channel| channel.as_directed_to(target))
+                                               .map(|(info, _)| CandidateRouteHop::PublicHop(PublicHopCandidate {
                                                        info,
                                                        short_channel_id: hop.short_channel_id,
-                                               })
-                                               .unwrap_or_else(|| CandidateRouteHop::PrivateHop { hint: hop, target_node_id: target });
+                                               }))
+                                               .unwrap_or_else(|| CandidateRouteHop::PrivateHop(PrivateHopCandidate { hint: hop, target_node_id: target }));
 
                                        if let Some(hop_used_msat) = add_entry!(&candidate,
                                                aggregate_next_hops_fee_msat, aggregate_path_contribution_msat,
@@ -2565,13 +2630,13 @@ where L::Target: Logger {
                                                .saturating_add(1);
 
                                        // Searching for a direct channel between last checked hop and first_hop_targets
-                                       if let Some(first_channels) = first_hop_targets.get_mut(&target) {
+                                       if let Some(first_channels) = first_hop_targets.get_mut(target) {
                                                sort_first_hop_channels(first_channels, &used_liquidities,
                                                        recommended_value_msat, our_node_pubkey);
                                                for details in first_channels {
-                                                       let first_hop_candidate = CandidateRouteHop::FirstHop {
+                                                       let first_hop_candidate = CandidateRouteHop::FirstHop(FirstHopCandidate {
                                                                details, payer_node_id: &our_node_id,
-                                                       };
+                                                       });
                                                        add_entry!(&first_hop_candidate,
                                                                aggregate_next_hops_fee_msat, aggregate_path_contribution_msat,
                                                                aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat,
@@ -2616,9 +2681,9 @@ where L::Target: Logger {
                                                        sort_first_hop_channels(first_channels, &used_liquidities,
                                                                recommended_value_msat, our_node_pubkey);
                                                        for details in first_channels {
-                                                               let first_hop_candidate = CandidateRouteHop::FirstHop {
+                                                               let first_hop_candidate = CandidateRouteHop::FirstHop(FirstHopCandidate {
                                                                        details, payer_node_id: &our_node_id,
-                                                               };
+                                                               });
                                                                add_entry!(&first_hop_candidate,
                                                                        aggregate_next_hops_fee_msat,
                                                                        aggregate_path_contribution_msat,
@@ -2661,7 +2726,7 @@ where L::Target: Logger {
                                        let target = ordered_hops.last().unwrap().0.candidate.target().unwrap_or(maybe_dummy_payee_node_id);
                                        if let Some(first_channels) = first_hop_targets.get(&target) {
                                                for details in first_channels {
-                                                       if let CandidateRouteHop::FirstHop { details: last_hop_details, .. }
+                                                       if let CandidateRouteHop::FirstHop(FirstHopCandidate { details: last_hop_details, .. })
                                                                = ordered_hops.last().unwrap().0.candidate
                                                        {
                                                                if details.get_outbound_payment_scid() == last_hop_details.get_outbound_payment_scid() {
@@ -2686,7 +2751,7 @@ where L::Target: Logger {
                                                }
                                        }
 
-                                       // Means we succesfully traversed from the payer to the payee, now
+                                       // Means we successfully traversed from the payer to the payee, now
                                        // save this path for the payment route. Also, update the liquidity
                                        // remaining on the used hops, so that we take them into account
                                        // while looking for more paths.
@@ -2928,12 +2993,12 @@ where L::Target: Logger {
                        .filter(|(h, _)| h.candidate.short_channel_id().is_some())
                {
                        let target = hop.candidate.target().expect("target is defined when short_channel_id is defined");
-                       let maybe_announced_channel = if let CandidateRouteHop::PublicHop { .. } = hop.candidate {
+                       let maybe_announced_channel = if let CandidateRouteHop::PublicHop(_) = hop.candidate {
                                // If we sourced the hop from the graph we're sure the target node is announced.
                                true
-                       } else if let CandidateRouteHop::FirstHop { details, .. } = hop.candidate {
+                       } else if let CandidateRouteHop::FirstHop(first_hop) = &hop.candidate {
                                // If this is a first hop we also know if it's announced.
-                               details.is_public
+                               first_hop.details.is_public
                        } else {
                                // If we sourced it any other way, we double-check the network graph to see if
                                // there are announced channels between the endpoints. If so, the hop might be
@@ -3163,7 +3228,7 @@ mod tests {
        use crate::routing::utxo::UtxoResult;
        use crate::routing::router::{get_route, build_route_from_hops_internal, add_random_cltv_offset, default_node_features,
                BlindedTail, InFlightHtlcs, Path, PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees,
-               DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, MAX_PATH_LENGTH_ESTIMATE, RouteParameters, CandidateRouteHop};
+               DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, MAX_PATH_LENGTH_ESTIMATE, RouteParameters, CandidateRouteHop, PublicHopCandidate};
        use crate::routing::scoring::{ChannelUsage, FixedPenaltyScorer, ScoreLookUp, ProbabilisticScorer, ProbabilisticScoringFeeParameters, ProbabilisticScoringDecayParameters};
        use crate::routing::test_utils::{add_channel, add_or_update_node, build_graph, build_line_graph, id_to_feature_flags, get_nodes, update_channel};
        use crate::chain::transaction::OutPoint;
@@ -3175,7 +3240,7 @@ mod tests {
        use crate::offers::invoice::BlindedPayInfo;
        use crate::util::config::UserConfig;
        use crate::util::test_utils as ln_test_utils;
-       use crate::util::chacha20::ChaCha20;
+       use crate::crypto::chacha20::ChaCha20;
        use crate::util::ser::{Readable, Writeable};
        #[cfg(c_bindings)]
        use crate::util::ser::Writer;
@@ -3194,8 +3259,6 @@ mod tests {
        use crate::prelude::*;
        use crate::sync::Arc;
 
-       use core::convert::TryInto;
-
        fn get_channel_details(short_channel_id: Option<u64>, node_id: PublicKey,
                        features: InitFeatures, outbound_capacity_msat: u64) -> channelmanager::ChannelDetails {
                channelmanager::ChannelDetails {
@@ -3231,6 +3294,8 @@ mod tests {
                        config: None,
                        feerate_sat_per_1000_weight: None,
                        channel_shutdown_state: Some(channelmanager::ChannelShutdownState::NotShuttingDown),
+                       pending_inbound_htlcs: Vec::new(),
+                       pending_outbound_htlcs: Vec::new(),
                }
        }
 
@@ -6882,7 +6947,7 @@ mod tests {
                        (route.paths[1].hops[1].short_channel_id == 4 && route.paths[0].hops[1].short_channel_id == 13));
        }
 
-       #[cfg(not(feature = "no-std"))]
+       #[cfg(feature = "std")]
        pub(super) fn random_init_seed() -> u64 {
                // Because the default HashMap in std pulls OS randomness, we can use it as a (bad) RNG.
                use core::hash::{BuildHasher, Hasher};
@@ -6892,7 +6957,7 @@ mod tests {
        }
 
        #[test]
-       #[cfg(not(feature = "no-std"))]
+       #[cfg(feature = "std")]
        fn generate_routes() {
                use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
 
@@ -6913,7 +6978,7 @@ mod tests {
        }
 
        #[test]
-       #[cfg(not(feature = "no-std"))]
+       #[cfg(feature = "std")]
        fn generate_routes_mpp() {
                use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
 
@@ -6934,7 +6999,7 @@ mod tests {
        }
 
        #[test]
-       #[cfg(not(feature = "no-std"))]
+       #[cfg(feature = "std")]
        fn generate_large_mpp_routes() {
                use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
 
@@ -6977,10 +7042,10 @@ mod tests {
                let channels = network_graph.channels();
                let channel = channels.get(&5).unwrap();
                let info = channel.as_directed_from(&NodeId::from_pubkey(&nodes[3])).unwrap();
-               let candidate: CandidateRouteHop = CandidateRouteHop::PublicHop {
+               let candidate: CandidateRouteHop = CandidateRouteHop::PublicHop(PublicHopCandidate {
                        info: info.0,
                        short_channel_id: 5,
-               };
+               });
                assert_eq!(scorer.channel_penalty_msat(&candidate, usage, &scorer_params), 456);
 
                // Then check we can get a normal route
@@ -7783,7 +7848,7 @@ mod tests {
        fn do_min_htlc_overpay_violates_max_htlc(blinded_payee: bool) {
                // Test that if overpaying to meet a later hop's min_htlc and causes us to violate an earlier
                // hop's max_htlc, we don't consider that candidate hop valid. Previously we would add this hop
-               // to `targets` and build an invalid path with it, and subsquently hit a debug panic asserting
+               // to `targets` and build an invalid path with it, and subsequently hit a debug panic asserting
                // that the used liquidity for a hop was less than its available liquidity limit.
                let secp_ctx = Secp256k1::new();
                let logger = Arc::new(ln_test_utils::TestLogger::new());
@@ -8270,24 +8335,21 @@ mod tests {
        }
 }
 
-#[cfg(all(any(test, ldk_bench), not(feature = "no-std")))]
+#[cfg(all(any(test, ldk_bench), feature = "std"))]
 pub(crate) mod bench_utils {
        use super::*;
        use std::fs::File;
        use std::time::Duration;
 
        use bitcoin::hashes::Hash;
-       use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
+       use bitcoin::secp256k1::SecretKey;
 
        use crate::chain::transaction::OutPoint;
        use crate::routing::scoring::ScoreUpdate;
-       use crate::sign::{EntropySource, KeysManager};
+       use crate::sign::KeysManager;
        use crate::ln::ChannelId;
-       use crate::ln::channelmanager::{self, ChannelCounterparty, ChannelDetails};
-       use crate::ln::features::Bolt11InvoiceFeatures;
-       use crate::routing::gossip::NetworkGraph;
+       use crate::ln::channelmanager::{self, ChannelCounterparty};
        use crate::util::config::UserConfig;
-       use crate::util::ser::ReadableArgs;
        use crate::util::test_utils::TestLogger;
 
        /// Tries to open a network graph file, or panics with a URL to fetch it.
@@ -8372,6 +8434,8 @@ pub(crate) mod bench_utils {
                        config: None,
                        feerate_sat_per_1000_weight: None,
                        channel_shutdown_state: Some(channelmanager::ChannelShutdownState::NotShuttingDown),
+                       pending_inbound_htlcs: Vec::new(),
+                       pending_outbound_htlcs: Vec::new(),
                }
        }
 
@@ -8432,7 +8496,7 @@ pub(crate) mod bench_utils {
                                                        }
                                                        break;
                                                }
-                                               // If we couldn't find a path with a higer amount, reduce and try again.
+                                               // If we couldn't find a path with a higher amount, reduce and try again.
                                                score_amt /= 100;
                                        }