Prefetch per-direction channel info before looking at the channel
[rust-lightning] / lightning / src / routing / router.rs
index 9423078749d39175790a6f298831048db5482a63..75bd47fb91b5798a1d580a4343b1059b1c764fb9 100644 (file)
@@ -9,18 +9,21 @@
 
 //! The router finds paths within a [`NetworkGraph`] for a payment.
 
-use bitcoin::secp256k1::PublicKey;
+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::features::{Bolt11InvoiceFeatures, Bolt12InvoiceFeatures, ChannelFeatures, NodeFeatures};
+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::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;
@@ -33,7 +36,7 @@ use core::{cmp, fmt};
 use core::ops::Deref;
 
 /// A [`Router`] implemented using [`find_route`].
-pub struct DefaultRouter<G: Deref<Target = NetworkGraph<L>>, L: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> where
+pub struct DefaultRouter<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> where
        L::Target: Logger,
        S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,
 {
@@ -41,21 +44,23 @@ pub struct DefaultRouter<G: Deref<Target = NetworkGraph<L>>, L: Deref, S: Deref,
        logger: L,
        random_seed_bytes: Mutex<[u8; 32]>,
        scorer: S,
-       score_params: SP
+       score_params: SP,
+       message_router: DefaultMessageRouter<G, L>,
 }
 
-impl<G: Deref<Target = NetworkGraph<L>>, 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, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> DefaultRouter<G, L, S, SP, Sc> where
        L::Target: Logger,
        S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,
 {
        /// 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);
-               Self { network_graph, logger, random_seed_bytes, scorer, score_params }
+               let message_router = DefaultMessageRouter::new(network_graph.clone());
+               Self { network_graph, logger, random_seed_bytes, scorer, score_params, message_router }
        }
 }
 
-impl< G: Deref<Target = NetworkGraph<L>>, 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, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> Router for DefaultRouter<G, L, S, SP, Sc> where
        L::Target: Logger,
        S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,
 {
@@ -78,10 +83,109 @@ impl< G: Deref<Target = NetworkGraph<L>>, L: Deref, S: Deref, SP: Sized, Sc: Sco
                        &random_seed_bytes
                )
        }
+
+       fn create_blinded_payment_paths<
+               ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification
+       >(
+               &self, recipient: PublicKey, first_hops: Vec<ChannelDetails>, tlvs: ReceiveTlvs,
+               amount_msats: u64, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+       ) -> Result<Vec<(BlindedPayInfo, BlindedPath)>, ()> {
+               // Limit the number of blinded paths that are computed.
+               const MAX_PAYMENT_PATHS: usize = 3;
+
+               // Ensure peers have at least three channels so that it is more difficult to infer the
+               // recipient's node_id.
+               const MIN_PEER_CHANNELS: usize = 3;
+
+               let network_graph = self.network_graph.deref().read_only();
+               let paths = first_hops.into_iter()
+                       .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(u64::MAX))
+                       .filter(|details| network_graph
+                                       .node(&NodeId::from_pubkey(&details.counterparty.node_id))
+                                       .map(|node_info| node_info.channels.len() >= MIN_PEER_CHANNELS)
+                                       .unwrap_or(false)
+                       )
+                       .filter_map(|details| {
+                               let short_channel_id = match details.get_inbound_payment_scid() {
+                                       Some(short_channel_id) => short_channel_id,
+                                       None => return None,
+                               };
+                               let payment_relay: PaymentRelay = match details.counterparty.forwarding_info {
+                                       Some(forwarding_info) => forwarding_info.into(),
+                                       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 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),
+                               };
+                               Some(ForwardNode {
+                                       tlvs: ForwardTlvs {
+                                               short_channel_id,
+                                               payment_relay,
+                                               payment_constraints,
+                                               features: BlindedHopFeatures::empty(),
+                                       },
+                                       node_id: details.counterparty.node_id,
+                                       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
+                               )
+                       })
+                       .take(MAX_PAYMENT_PATHS)
+                       .collect::<Result<Vec<_>, _>>();
+
+               match paths {
+                       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])
+                               } else {
+                                       Err(())
+                               }
+                       },
+               }
+       }
+}
+
+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
+       L::Target: Logger,
+       S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,
+{
+       fn find_path(
+               &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
+       ) -> Result<OnionMessagePath, ()> {
+               self.message_router.find_path(sender, peers, destination)
+       }
+
+       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>
+       ) -> Result<Vec<BlindedPath>, ()> {
+               self.message_router.create_blinded_paths(recipient, peers, entropy_source, secp_ctx)
+       }
 }
 
 /// A trait defining behavior for routing a payment.
-pub trait Router {
+pub trait Router: MessageRouter {
        /// Finds a [`Route`] for a payment between the given `payer` and a payee.
        ///
        /// The `payee` and the payment's value are given in [`RouteParameters::payment_params`]
@@ -105,6 +209,16 @@ pub trait Router {
        ) -> Result<Route, LightningError> {
                self.find_route(payer, route_params, first_hops, inflight_htlcs)
        }
+
+       /// Creates [`BlindedPath`]s for payment to the `recipient` node. The channels in `first_hops`
+       /// 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
+       >(
+               &self, recipient: PublicKey, first_hops: Vec<ChannelDetails>, tlvs: ReceiveTlvs,
+               amount_msats: u64, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+       ) -> Result<Vec<(BlindedPayInfo, BlindedPath)>, ()>;
 }
 
 /// [`ScoreLookUp`] implementation that factors in in-flight HTLC liquidity.
@@ -997,14 +1111,94 @@ impl cmp::PartialOrd for RouteGraphNode {
 
 // While RouteGraphNode can be laid out with fewer bytes, performance appears to be improved
 // substantially when it is laid out at exactly 64 bytes.
-//
-// Thus, we use `#[repr(C)]` on the struct to force a suboptimal layout and check that it stays 64
-// bytes here.
-#[cfg(any(ldk_bench, not(any(test, fuzzing))))]
 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 CandidateFirstHop<'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`].
+       pub details: &'a ChannelDetails,
+       /// The node id of the payer, which is also the source side of this candidate route hop.
+       pub payer_node_id: &'a NodeId,
+       /// A unique ID which describes the payer. It will not conlict with any
+       /// [`NodeInfo::node_counter`]s, but may be equal to one if the payer is a public node.
+       payer_node_counter: u32,
+       /// A unique ID which describes the first hop counterparty. It will not conlict with any
+       /// [`NodeInfo::node_counter`]s, but may be equal to one if the counterparty is a public node.
+       target_node_counter: u32,
+}
+
+/// A [`CandidateRouteHop::PublicHop`] entry.
+#[derive(Clone, Debug)]
+pub struct CandidatePublicHop<'a> {
+       /// Information about the channel, including potentially its capacity and
+       /// direction-specific information.
+       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 CandidatePrivateHop<'a> {
+       /// Information about the private hop communicated via BOLT 11.
+       pub hint: &'a RouteHintHop,
+       /// Node id of the next hop in BOLT 11 route hint.
+       pub target_node_id: &'a NodeId,
+       /// A unique ID which describes the source node of the hop (further from the payment target).
+       /// It will not conlict with any [`NodeInfo::node_counter`]s, but may be equal to one if the
+       /// node is a public node.
+       source_node_counter: u32,
+       /// A unique ID which describes the destination node of the hop (towards the payment target).
+       /// It will not conlict with any [`NodeInfo::node_counter`]s, but may be equal to one if the
+       /// node is a public node.
+       target_node_counter: u32,
+
+}
+
+/// A [`CandidateRouteHop::Blinded`] entry.
+#[derive(Clone, Debug)]
+pub struct CandidateBlindedPath<'a> {
+       /// Information about the blinded path including the fee, HTLC amount limits, and
+       /// cryptographic material required to build an HTLC through the given path.
+       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 unique ID which describes the introduction point of the blinded path.
+       /// It will not conlict with any [`NodeInfo::node_counter`]s, but will generally be equal to
+       /// one from the public network graph (assuming the introduction point is a public node).
+       source_node_counter: u32,
+}
+
+/// A [`CandidateRouteHop::OneHopBlinded`] entry.
+#[derive(Clone, Debug)]
+pub struct CandidateOneHopBlindedPath<'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.
+       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 unique ID which describes the introduction point of the blinded path.
+       /// It will not conlict with any [`NodeInfo::node_counter`]s, but will generally be equal to
+       /// one from the public network graph (assuming the introduction point is a public node).
+       source_node_counter: u32,
+}
+
 /// A wrapper around the various hop representations.
 ///
 /// Can be used to examine the properties of a hop,
@@ -1012,36 +1206,14 @@ 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(CandidateFirstHop<'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(CandidatePublicHop<'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(CandidatePrivateHop<'a>),
        /// A blinded path which starts with an introduction point and ultimately terminates with the
        /// payee.
        ///
@@ -1050,16 +1222,7 @@ 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(CandidateBlindedPath<'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.
@@ -1071,18 +1234,7 @@ 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(CandidateOneHopBlindedPath<'a>),
 }
 
 impl<'a> CandidateRouteHop<'a> {
@@ -1104,11 +1256,11 @@ 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,
                }
        }
 
@@ -1120,22 +1272,22 @@ 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(),
                }
        }
 
@@ -1147,11 +1299,11 @@ 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,
                }
        }
 
@@ -1159,30 +1311,52 @@ 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,
                }
        }
 
+       #[inline(always)]
+       fn src_node_counter(&self) -> u32 {
+               match self {
+                       CandidateRouteHop::FirstHop { payer_node_counter, .. } => *payer_node_counter,
+                       CandidateRouteHop::PublicHop { info, .. } => info.source_counter(),
+                       CandidateRouteHop::PrivateHop { source_node_counter, .. } => *source_node_counter,
+                       CandidateRouteHop::Blinded { source_node_counter, .. } => *source_node_counter,
+                       CandidateRouteHop::OneHopBlinded { source_node_counter, .. } => *source_node_counter,
+               }
+       }
+
+       #[inline]
+       fn target_node_counter(&self) -> Option<u32> {
+               match self {
+                       CandidateRouteHop::FirstHop { target_node_counter, .. } => Some(*target_node_counter),
+                       CandidateRouteHop::PublicHop { info, .. } => Some(info.target_counter()),
+                       CandidateRouteHop::PrivateHop { target_node_counter, .. } => Some(*target_node_counter),
+                       CandidateRouteHop::Blinded { .. } => None,
+                       CandidateRouteHop::OneHopBlinded { .. } => None,
+               }
+       }
+
        /// Returns the fees that must be paid to route an HTLC over this channel.
        #[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 },
                }
        }
@@ -1193,17 +1367,17 @@ 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(CandidatePrivateHop { hint: RouteHintHop { htlc_maximum_msat: Some(max), .. }, .. }) =>
                                EffectiveCapacity::HintMaxHTLC { amount_msat: *max },
-                       CandidateRouteHop::PrivateHop { hint: RouteHintHop { htlc_maximum_msat: None, .. }, .. } =>
+                       CandidateRouteHop::PrivateHop(CandidatePrivateHop { 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,
                }
        }
 
@@ -1213,14 +1387,14 @@ 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(CandidateBlindedPath { hint, .. }) | CandidateRouteHop::OneHopBlinded(CandidateOneHopBlindedPath { hint, .. }) => {
                                Some(&hint.1)
                        },
                        _ => None,
@@ -1234,11 +1408,11 @@ 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.
@@ -1253,11 +1427,11 @@ 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,
                }
        }
 }
@@ -1307,20 +1481,57 @@ fn iter_equal<I1: Iterator, I2: Iterator>(mut iter_a: I1, mut iter_b: I2)
        }
 }
 
+#[cfg(target_feature = "sse")]
+#[inline(always)]
+unsafe fn do_prefetch<T>(ptr: *const T) {
+       #[cfg(target_arch = "x86_64")]
+       use core::arch::x86_64::*;
+       #[cfg(target_arch = "x86")]
+       use core::arch::x86::*;
+       _mm_prefetch(ptr as *const i8, _MM_HINT_T0);
+}
+
+#[cfg(not(target_feature = "sse"))]
+#[inline(always)]
+unsafe fn do_prefetch<T>(_: *const T) {}
+
+#[inline(always)]
+fn prefetch_first_byte<T>(t: &T) {
+       // While X86's prefetch should be safe even on an invalid memory address (the ISA says
+       // "PREFETCHh instruction is merely a hint and does not affect program behavior"), we take
+       // an extra step towards safety here by requiring the pointer be valid (as Rust references
+       // are always valid when accessed).
+       //
+       // Note that a pointer in Rust could be to a zero sized type, in which case the pointer could
+       // be NULL (or some other bogus value), so we explicitly check for that here.
+       if ::core::mem::size_of::<T>() != 0 {
+               unsafe { do_prefetch(t) }
+       }
+}
+
 /// It's useful to keep track of the hops associated with the fees required to use them,
 /// so that we can choose cheaper paths (as per Dijkstra's algorithm).
 /// Fee values should be updated only in the context of the whole path, see update_value_and_recompute_fees.
 /// These fee values are useful to choose hops as we traverse the graph "payee-to-payer".
 #[derive(Clone)]
-#[repr(C)] // Force fields to appear in the order we define them.
+#[repr(align(128))]
 struct PathBuildingHop<'a> {
        candidate: CandidateRouteHop<'a>,
+       target_node_counter: Option<u32>,
        /// If we've already processed a node as the best node, we shouldn't process it again. Normally
        /// we'd just ignore it if we did as all channels would have a higher new fee, but because we
        /// may decrease the amounts in use as we walk the graph, the actual calculated fee may
        /// decrease as well. Thus, we have to explicitly track which nodes have been processed and
        /// avoid processing them again.
        was_processed: bool,
+       /// When processing a node as the next best-score candidate, we want to quickly check if it is
+       /// a direct counterparty of ours, using our local channel information immediately if we can.
+       ///
+       /// In order to do so efficiently, we cache whether a node is a direct counterparty here at the
+       /// start of a route-finding pass. Unlike all other fields in this struct, this field is never
+       /// updated after being initialized - it is set at the start of a route-finding pass and only
+       /// read thereafter.
+       is_first_hop_target: bool,
        /// Used to compare channels when choosing the for routing.
        /// Includes paying for the use of a hop and the following hops, as well as
        /// an estimated cost of reaching this hop.
@@ -1333,11 +1544,6 @@ struct PathBuildingHop<'a> {
        /// channel scoring.
        path_penalty_msat: u64,
 
-       // The last 16 bytes are on the next cache line by default in glibc's malloc. Thus, we should
-       // only place fields which are not hot there. Luckily, the next three fields are only read if
-       // we end up on the selected path, and only in the final path layout phase, so we don't care
-       // too much if reading them is slow.
-
        fee_msat: u64,
 
        /// All the fees paid *after* this channel on the way to the destination
@@ -1354,28 +1560,20 @@ struct PathBuildingHop<'a> {
        value_contribution_msat: u64,
 }
 
-// Checks that the entries in the `find_route` `dist` map fit in (exactly) two standard x86-64
-// cache lines. Sadly, they're not guaranteed to actually lie on a cache line (and in fact,
-// generally won't, because at least glibc's malloc will align to a nice, big, round
-// boundary...plus 16), but at least it will reduce the amount of data we'll need to load.
-//
-// Note that these assertions only pass on somewhat recent rustc, and thus are gated on the
-// ldk_bench flag.
-#[cfg(ldk_bench)]
-const _NODE_MAP_SIZE_TWO_CACHE_LINES: usize = 128 - core::mem::size_of::<(NodeId, PathBuildingHop)>();
-#[cfg(ldk_bench)]
-const _NODE_MAP_SIZE_EXACTLY_CACHE_LINES: usize = core::mem::size_of::<(NodeId, PathBuildingHop)>() - 128;
+const _NODE_MAP_SIZE_TWO_CACHE_LINES: usize = 128 - core::mem::size_of::<Option<PathBuildingHop>>();
+const _NODE_MAP_SIZE_EXACTLY_TWO_CACHE_LINES: usize = core::mem::size_of::<Option<PathBuildingHop>>() - 128;
 
 impl<'a> core::fmt::Debug for PathBuildingHop<'a> {
        fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
                let mut debug_struct = f.debug_struct("PathBuildingHop");
                debug_struct
-                       .field("node_id", &self.candidate.target())
+                       .field("source_node_id", &self.candidate.source())
+                       .field("target_node_id", &self.candidate.target())
                        .field("short_channel_id", &self.candidate.short_channel_id())
                        .field("total_fee_msat", &self.total_fee_msat)
                        .field("next_hops_fee_msat", &self.next_hops_fee_msat)
                        .field("hop_use_fee_msat", &self.hop_use_fee_msat)
-                       .field("total_fee_msat - (next_hops_fee_msat + hop_use_fee_msat)", &(&self.total_fee_msat - (&self.next_hops_fee_msat + &self.hop_use_fee_msat)))
+                       .field("total_fee_msat - (next_hops_fee_msat + hop_use_fee_msat)", &(&self.total_fee_msat.saturating_sub(self.next_hops_fee_msat).saturating_sub(self.hop_use_fee_msat)))
                        .field("path_penalty_msat", &self.path_penalty_msat)
                        .field("path_htlc_minimum_msat", &self.path_htlc_minimum_msat)
                        .field("cltv_expiry_delta", &self.candidate.cltv_expiry_delta());
@@ -1552,17 +1750,17 @@ 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(CandidateBlindedPath { hint, .. }) | CandidateRouteHop::OneHopBlinded(CandidateOneHopBlindedPath { 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)
                        },
@@ -1796,11 +1994,42 @@ where L::Target: Logger {
                first_hops.map(|hops| hops.len()).unwrap_or(0), if first_hops.is_some() { "" } else { "not " },
                max_total_routing_fee_msat);
 
+       let private_hop_targets_node_counter_offset = network_graph.max_node_counter() + 2;
+       let mut private_node_id_to_node_counter = HashMap::new();
+
+       let mut private_hop_key_cache = HashMap::with_capacity(
+               payment_params.payee.unblinded_route_hints().iter().map(|path| path.0.len()).sum()
+       );
+
+       // Because we store references to private hop node_ids in `dist`, below, we need them to exist
+       // (as `NodeId`, not `PublicKey`) for the lifetime of `dist`. Thus, we calculate all the keys
+       // we'll need here and simply fetch them when routing.
+       let payee_node_counter = payee_node_id_opt
+               .and_then(|payee| network_nodes.get(&payee))
+               .map(|node| node.node_counter)
+               .unwrap_or(private_hop_targets_node_counter_offset);
+       private_node_id_to_node_counter.insert(maybe_dummy_payee_node_id, payee_node_counter);
+       private_hop_key_cache.insert(maybe_dummy_payee_pk, (NodeId::from_pubkey(&maybe_dummy_payee_pk), payee_node_counter));
+
+       for route in payment_params.payee.unblinded_route_hints().iter() {
+               for hop in route.0.iter() {
+                       let hop_node_id = NodeId::from_pubkey(&hop.src_node_id);
+                       let node_counter = if let Some(node) = network_nodes.get(&hop_node_id) {
+                               node.node_counter
+                       } else {
+                               let next_node_counter = private_hop_targets_node_counter_offset + private_node_id_to_node_counter.len() as u32;
+                               *private_node_id_to_node_counter.entry(hop_node_id)
+                                       .or_insert(next_node_counter)
+                       };
+                       private_hop_key_cache.insert(hop.src_node_id, (hop_node_id, node_counter));
+               }
+       }
+
        // Step (1).
        // Prepare the data we'll use for payee-to-payer search by
        // 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>> =
+       let mut first_hop_targets: HashMap<_, (Vec<&ChannelDetails>, u32)> =
                HashMap::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 {
@@ -1810,30 +2039,26 @@ where L::Target: Logger {
                        if chan.counterparty.node_id == *our_node_pubkey {
                                return Err(LightningError{err: "First hop cannot have our_node_pubkey as a destination.".to_owned(), action: ErrorAction::IgnoreError});
                        }
+                       let counterparty_node_id = NodeId::from_pubkey(&chan.counterparty.node_id);
                        first_hop_targets
-                               .entry(NodeId::from_pubkey(&chan.counterparty.node_id))
-                               .or_insert(Vec::new())
-                               .push(chan);
+                               .entry(counterparty_node_id)
+                               .or_insert_with(|| {
+                                       let node_counter = if let Some(node) = network_nodes.get(&counterparty_node_id) {
+                                               node.node_counter
+                                       } else {
+                                               let next_node_counter = private_hop_targets_node_counter_offset + private_node_id_to_node_counter.len() as u32;
+                                               *private_node_id_to_node_counter.entry(counterparty_node_id)
+                                                       .or_insert(next_node_counter)
+                                       };
+                                       (Vec::new(), node_counter)
+                               })
+                               .0.push(chan);
                }
                if first_hop_targets.is_empty() {
                        return Err(LightningError{err: "Cannot route when there are no outbound routes away from us".to_owned(), action: ErrorAction::IgnoreError});
                }
        }
 
-       let mut private_hop_key_cache = HashMap::with_capacity(
-               payment_params.payee.unblinded_route_hints().iter().map(|path| path.0.len()).sum()
-       );
-
-       // Because we store references to private hop node_ids in `dist`, below, we need them to exist
-       // (as `NodeId`, not `PublicKey`) for the lifetime of `dist`. Thus, we calculate all the keys
-       // we'll need here and simply fetch them when routing.
-       private_hop_key_cache.insert(maybe_dummy_payee_pk, NodeId::from_pubkey(&maybe_dummy_payee_pk));
-       for route in payment_params.payee.unblinded_route_hints().iter() {
-               for hop in route.0.iter() {
-                       private_hop_key_cache.insert(hop.src_node_id, NodeId::from_pubkey(&hop.src_node_id));
-               }
-       }
-
        // The main heap containing all candidate next-hops sorted by their score (max(fee,
        // htlc_minimum)). Ideally this would be a heap which allowed cheap score reduction instead of
        // adding duplicate entries when we find a better path to a given node.
@@ -1841,7 +2066,15 @@ 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 dist_len = private_hop_targets_node_counter_offset + private_hop_key_cache.len() as u32 + 1;
+       let mut dist: Vec<Option<PathBuildingHop>> = vec![None; dist_len as usize];
+       let payer_node_counter = network_nodes
+               .get(&our_node_id)
+               .map(|node| node.node_counter)
+               .or_else(|| {
+                       private_node_id_to_node_counter.get(&our_node_id).map(|counter| *counter)
+               })
+               .unwrap_or(network_graph.max_node_counter() + 1);
 
        // 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
@@ -1888,7 +2121,7 @@ where L::Target: Logger {
        // when we want to stop looking for new paths.
        let mut already_collected_value_msat = 0;
 
-       for (_, channels) in first_hop_targets.iter_mut() {
+       for (_, (channels, _)) in first_hop_targets.iter_mut() {
                sort_first_hop_channels(channels, &used_liquidities, recommended_value_msat,
                        our_node_pubkey);
        }
@@ -1934,6 +2167,8 @@ where L::Target: Logger {
                                // if the amount being transferred over this path is lower.
                                // We do this for now, but this is a subject for removal.
                                if let Some(mut available_value_contribution_msat) = htlc_maximum_msat.checked_sub($next_hops_fee_msat) {
+                                       let cltv_expiry_delta = $candidate.cltv_expiry_delta();
+                                       let htlc_minimum_msat = $candidate.htlc_minimum_msat();
                                        let used_liquidity_msat = used_liquidities
                                                .get(&$candidate.id())
                                                .map_or(0, |used_liquidity_msat| {
@@ -1956,7 +2191,7 @@ where L::Target: Logger {
                                                .checked_sub(2*MEDIAN_HOP_CLTV_EXPIRY_DELTA)
                                                .unwrap_or(payment_params.max_total_cltv_expiry_delta - final_cltv_expiry_delta);
                                        let hop_total_cltv_delta = ($next_hops_cltv_delta as u32)
-                                               .saturating_add($candidate.cltv_expiry_delta());
+                                               .saturating_add(cltv_expiry_delta);
                                        let exceeds_cltv_delta_limit = hop_total_cltv_delta > max_total_cltv_expiry_delta;
 
                                        let value_contribution_msat = cmp::min(available_value_contribution_msat, $next_hops_value_contribution);
@@ -1967,13 +2202,13 @@ where L::Target: Logger {
                                                None => unreachable!(),
                                        };
                                        #[allow(unused_comparisons)] // $next_hops_path_htlc_minimum_msat is 0 in some calls so rustc complains
-                                       let over_path_minimum_msat = amount_to_transfer_over_msat >= $candidate.htlc_minimum_msat() &&
+                                       let over_path_minimum_msat = amount_to_transfer_over_msat >= htlc_minimum_msat &&
                                                amount_to_transfer_over_msat >= $next_hops_path_htlc_minimum_msat;
 
                                        #[allow(unused_comparisons)] // $next_hops_path_htlc_minimum_msat is 0 in some calls so rustc complains
                                        let may_overpay_to_meet_path_minimum_msat =
-                                               ((amount_to_transfer_over_msat < $candidate.htlc_minimum_msat() &&
-                                                 recommended_value_msat >= $candidate.htlc_minimum_msat()) ||
+                                               ((amount_to_transfer_over_msat < htlc_minimum_msat &&
+                                                 recommended_value_msat >= htlc_minimum_msat) ||
                                                 (amount_to_transfer_over_msat < $next_hops_path_htlc_minimum_msat &&
                                                  recommended_value_msat >= $next_hops_path_htlc_minimum_msat));
 
@@ -1981,10 +2216,10 @@ where L::Target: Logger {
                                                |scid| payment_params.previously_failed_channels.contains(&scid));
 
                                        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),
                                        };
 
@@ -2048,19 +2283,25 @@ where L::Target: Logger {
                                                // payment path (upstream to the payee). To avoid that, we recompute
                                                // path fees knowing the final path contribution after constructing it.
                                                let curr_min = cmp::max(
-                                                       $next_hops_path_htlc_minimum_msat, $candidate.htlc_minimum_msat()
+                                                       $next_hops_path_htlc_minimum_msat, htlc_minimum_msat
                                                );
-                                               let path_htlc_minimum_msat = compute_fees_saturating(curr_min, $candidate.fees())
+                                               let candidate_fees = $candidate.fees();
+                                               let src_node_counter = $candidate.src_node_counter();
+                                               let path_htlc_minimum_msat = compute_fees_saturating(curr_min, candidate_fees)
                                                        .saturating_add(curr_min);
-                                               let hm_entry = dist.entry(src_node_id);
-                                               let old_entry = hm_entry.or_insert_with(|| {
+
+                                               let dist_entry = &mut dist[src_node_counter as usize];
+                                               let old_entry = if let Some(hop) = dist_entry {
+                                                       hop
+                                               } else {
                                                        // If there was previously no known way to access the source node
                                                        // (recall it goes payee-to-payer) of short_channel_id, first add a
                                                        // semi-dummy record just to compute the fees to reach the source node.
                                                        // This will affect our decision on selecting short_channel_id
                                                        // as a way to reach the $candidate.target() node.
-                                                       PathBuildingHop {
+                                                       *dist_entry = Some(PathBuildingHop {
                                                                candidate: $candidate.clone(),
+                                                               target_node_counter: None,
                                                                fee_msat: 0,
                                                                next_hops_fee_msat: u64::max_value(),
                                                                hop_use_fee_msat: u64::max_value(),
@@ -2068,10 +2309,12 @@ where L::Target: Logger {
                                                                path_htlc_minimum_msat,
                                                                path_penalty_msat: u64::max_value(),
                                                                was_processed: false,
+                                                               is_first_hop_target: false,
                                                                #[cfg(all(not(ldk_bench), any(test, fuzzing)))]
                                                                value_contribution_msat,
-                                                       }
-                                               });
+                                                       });
+                                                       dist_entry.as_mut().unwrap()
+                                               };
 
                                                #[allow(unused_mut)] // We only use the mut in cfg(test)
                                                let mut should_process = !old_entry.was_processed;
@@ -2091,7 +2334,7 @@ where L::Target: Logger {
                                                        if src_node_id != our_node_id {
                                                                // Note that `u64::max_value` means we'll always fail the
                                                                // `old_entry.total_fee_msat > total_fee_msat` check below
-                                                               hop_use_fee_msat = compute_fees_saturating(amount_to_transfer_over_msat, $candidate.fees());
+                                                               hop_use_fee_msat = compute_fees_saturating(amount_to_transfer_over_msat, candidate_fees);
                                                                total_fee_msat = total_fee_msat.saturating_add(hop_use_fee_msat);
                                                        }
 
@@ -2153,6 +2396,7 @@ where L::Target: Logger {
                                                                                path_length_to_node,
                                                                        };
                                                                        targets.push(new_graph_node);
+                                                                       old_entry.target_node_counter = $candidate.target_node_counter();
                                                                        old_entry.next_hops_fee_msat = $next_hops_fee_msat;
                                                                        old_entry.hop_use_fee_msat = hop_use_fee_msat;
                                                                        old_entry.total_fee_msat = total_fee_msat;
@@ -2230,34 +2474,42 @@ where L::Target: Logger {
                        let fee_to_target_msat;
                        let next_hops_path_htlc_minimum_msat;
                        let next_hops_path_penalty_msat;
-                       let skip_node = if let Some(elem) = dist.get_mut(&$node_id) {
+                       let is_first_hop_target;
+                       let skip_node = if let Some(elem) = &mut dist[$node.node_counter as usize] {
                                let was_processed = elem.was_processed;
                                elem.was_processed = true;
                                fee_to_target_msat = elem.total_fee_msat;
                                next_hops_path_htlc_minimum_msat = elem.path_htlc_minimum_msat;
                                next_hops_path_penalty_msat = elem.path_penalty_msat;
+                               is_first_hop_target = elem.is_first_hop_target;
                                was_processed
                        } else {
                                // Entries are added to dist in add_entry!() when there is a channel from a node.
                                // Because there are no channels from payee, it will not have a dist entry at this point.
                                // If we're processing any other node, it is always be the result of a channel from it.
                                debug_assert_eq!($node_id, maybe_dummy_payee_node_id);
+
                                fee_to_target_msat = 0;
                                next_hops_path_htlc_minimum_msat = 0;
                                next_hops_path_penalty_msat = 0;
+                               is_first_hop_target = false;
                                false
                        };
 
                        if !skip_node {
-                               if let Some(first_channels) = first_hop_targets.get(&$node_id) {
-                                       for details in first_channels {
-                                               let candidate = CandidateRouteHop::FirstHop {
-                                                       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,
-                                                       $next_hops_cltv_delta, $next_hops_path_length);
+                               if is_first_hop_target {
+                                       if let Some((first_channels, peer_node_counter)) = first_hop_targets.get(&$node_id) {
+                                               for details in first_channels {
+                                                       debug_assert_eq!(*peer_node_counter, $node.node_counter);
+                                                       let candidate = CandidateRouteHop::FirstHop(CandidateFirstHop {
+                                                               details, payer_node_id: &our_node_id, payer_node_counter,
+                                                               target_node_counter: $node.node_counter,
+                                                       });
+                                                       add_entry!(&candidate, fee_to_target_msat,
+                                                               $next_hops_value_contribution,
+                                                               next_hops_path_htlc_minimum_msat, next_hops_path_penalty_msat,
+                                                               $next_hops_cltv_delta, $next_hops_path_length);
+                                               }
                                        }
                                }
 
@@ -2270,14 +2522,21 @@ where L::Target: Logger {
                                if !features.requires_unknown_bits() {
                                        for chan_id in $node.channels.iter() {
                                                let chan = network_channels.get(chan_id).unwrap();
+                                               // Calling chan.as_directed_to, below, will require access to memory two
+                                               // cache lines away from chan.features (in the form of `one_to_two` or
+                                               // `two_to_one`, depending on our direction). Thus, while we're looking at
+                                               // feature flags, go ahead and prefetch that memory, reducing the price we
+                                               // pay for it later.
+                                               prefetch_first_byte(&chan.one_to_two);
+                                               prefetch_first_byte(&chan.two_to_one);
                                                if !chan.features.requires_unknown_bits() {
                                                        if let Some((directed_channel, source)) = chan.as_directed_to(&$node_id) {
                                                                if first_hops.is_none() || *source != our_node_id {
                                                                        if directed_channel.direction().enabled {
-                                                                               let candidate = CandidateRouteHop::PublicHop {
+                                                                               let candidate = CandidateRouteHop::PublicHop(CandidatePublicHop {
                                                                                        info: directed_channel,
                                                                                        short_channel_id: *chan_id,
-                                                                               };
+                                                                               });
                                                                                add_entry!(&candidate,
                                                                                        fee_to_target_msat,
                                                                                        $next_hops_value_contribution,
@@ -2301,16 +2560,47 @@ where L::Target: Logger {
                // For every new path, start from scratch, except for used_liquidities, which
                // helps to avoid reusing previously selected paths in future iterations.
                targets.clear();
-               dist.clear();
+               for e in dist.iter_mut() {
+                       *e = None;
+               }
+               for (node_id, (chans, peer_node_counter)) in first_hop_targets.iter() {
+                       // In order to avoid looking up whether each node is a first-hop target, we store a
+                       // dummy entry in dist for each first-hop target, allowing us to do this lookup for
+                       // free since we're already looking at the `was_processed` flag.
+                       //
+                       // Note that all the fields (except `is_first_hop_target`) will be overwritten whenever
+                       // we find a path to the target, so are left as dummies here.
+                       dist[*peer_node_counter as usize] = Some(PathBuildingHop {
+                               candidate: CandidateRouteHop::FirstHop {
+                                       details: &chans[0],
+                                       payer_node_id: &our_node_id,
+                                       target_node_counter: u32::max_value(),
+                                       payer_node_counter: u32::max_value(),
+                               },
+                               target_node_counter: None,
+                               fee_msat: 0,
+                               next_hops_fee_msat: u64::max_value(),
+                               hop_use_fee_msat: u64::max_value(),
+                               total_fee_msat: u64::max_value(),
+                               path_htlc_minimum_msat: u64::max_value(),
+                               path_penalty_msat: u64::max_value(),
+                               was_processed: false,
+                               is_first_hop_target: true,
+                               #[cfg(all(not(ldk_bench), any(test, fuzzing)))]
+                               value_contribution_msat: 0,
+                       });
+               }
                hit_minimum_limit = false;
 
                // If first hop is a private channel and the only way to reach the payee, this is the only
                // place where it could be added.
-               payee_node_id_opt.map(|payee| first_hop_targets.get(&payee).map(|first_channels| {
+               payee_node_id_opt.map(|payee| first_hop_targets.get(&payee).map(|(first_channels, peer_node_counter)| {
+                       debug_assert_eq!(*peer_node_counter, payee_node_counter);
                        for details in first_channels {
-                               let candidate = CandidateRouteHop::FirstHop {
-                                       details, payer_node_id: &our_node_id,
-                               };
+                               let candidate = CandidateRouteHop::FirstHop(CandidateFirstHop {
+                                       details, payer_node_id: &our_node_id, payer_node_counter,
+                                       target_node_counter: payee_node_counter,
+                               });
                                let added = add_entry!(&candidate, 0, path_value_msat,
                                                                        0, 0u64, 0, 0).is_some();
                                log_trace!(logger, "{} direct route to payee via {}",
@@ -2337,29 +2627,42 @@ where L::Target: Logger {
                // it matters only if the fees are exactly the same.
                for (hint_idx, hint) in payment_params.payee.blinded_route_hints().iter().enumerate() {
                        let intro_node_id = NodeId::from_pubkey(&hint.1.introduction_node_id);
-                       let have_intro_node_in_graph =
+                       let intro_node_counter_opt =
                                // Only add the hops in this route to our candidate set if either
                                // we have a direct channel to the first hop or the first hop is
                                // in the regular network graph.
-                               first_hop_targets.get(&intro_node_id).is_some() ||
-                               network_nodes.get(&intro_node_id).is_some();
-                       if !have_intro_node_in_graph || our_node_id == intro_node_id { continue }
+                               network_nodes.get(&intro_node_id).map(|node| node.node_counter)
+                               .or(
+                                       first_hop_targets.get(&intro_node_id).map(|(_, node_counter)| *node_counter)
+                               );
+                       if intro_node_counter_opt.is_none() || 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(CandidateOneHopBlindedPath {
+                                       hint,
+                                       hint_idx,
+                                       source_node_counter: intro_node_counter_opt.unwrap(),
+                               })
+                       } else {
+                               CandidateRouteHop::Blinded(CandidateBlindedPath {
+                                       hint,
+                                       hint_idx,
+                                       source_node_counter: intro_node_counter_opt.unwrap(),
+                               })
+                       };
                        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)
                        {
                                path_contribution_msat = hop_used_msat;
                        } else { continue }
-                       if let Some(first_channels) = first_hop_targets.get_mut(&NodeId::from_pubkey(&hint.1.introduction_node_id)) {
+                       if let Some((first_channels, peer_node_counter)) = first_hop_targets.get_mut(&NodeId::from_pubkey(&hint.1.introduction_node_id)) {
                                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 {
-                                               details, payer_node_id: &our_node_id,
-                                       };
+                                       let first_hop_candidate = CandidateRouteHop::FirstHop(CandidateFirstHop {
+                                               details, payer_node_id: &our_node_id, payer_node_counter,
+                                               target_node_counter: *peer_node_counter,
+                                       });
                                        let blinded_path_fee = match compute_fees(path_contribution_msat, candidate.fees()) {
                                                Some(fee) => fee,
                                                None => continue
@@ -2398,9 +2701,10 @@ 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_target_node_counter) = private_hop_key_cache.get(&prev_hop_id).unwrap();
+                                       let (_src_id, private_source_node_counter) = private_hop_key_cache.get(&hop.src_node_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);
@@ -2411,11 +2715,15 @@ 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 {
+                                               .map(|(info, _)| CandidateRouteHop::PublicHop(CandidatePublicHop {
                                                        info,
                                                        short_channel_id: hop.short_channel_id,
                                                })
-                                               .unwrap_or_else(|| CandidateRouteHop::PrivateHop { hint: hop, target_node_id: target });
+                                               .unwrap_or_else(|| CandidateRouteHop::PrivateHop(CandidatePrivateHop {
+                                                       hint: hop, target_node_id: target,
+                                                       source_node_counter: *private_source_node_counter,
+                                                       target_node_counter: *private_target_node_counter,
+                                               }));
 
                                        if let Some(hop_used_msat) = add_entry!(&candidate,
                                                aggregate_next_hops_fee_msat, aggregate_path_contribution_msat,
@@ -2451,13 +2759,14 @@ 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, peer_node_counter)) = 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 {
-                                                               details, payer_node_id: &our_node_id,
-                                                       };
+                                                       let first_hop_candidate = CandidateRouteHop::FirstHop(CandidateFirstHop {
+                                                               details, payer_node_id: &our_node_id, payer_node_counter,
+                                                               target_node_counter: *peer_node_counter,
+                                                       });
                                                        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,
@@ -2498,13 +2807,14 @@ where L::Target: Logger {
                                                // Note that we *must* check if the last hop was added as `add_entry`
                                                // always assumes that the third argument is a node to which we have a
                                                // path.
-                                               if let Some(first_channels) = first_hop_targets.get_mut(&NodeId::from_pubkey(&hop.src_node_id)) {
+                                               if let Some((first_channels, peer_node_counter)) = first_hop_targets.get_mut(&NodeId::from_pubkey(&hop.src_node_id)) {
                                                        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 {
-                                                                       details, payer_node_id: &our_node_id,
-                                                               };
+                                                               let first_hop_candidate = CandidateRouteHop::FirstHop(CandidateFirstHop {
+                                                                       details, payer_node_id: &our_node_id, payer_node_counter,
+                                                                       target_node_counter: *peer_node_counter,
+                                                               });
                                                                add_entry!(&first_hop_candidate,
                                                                        aggregate_next_hops_fee_msat,
                                                                        aggregate_path_contribution_msat,
@@ -2539,15 +2849,17 @@ where L::Target: Logger {
                        // Since we're going payee-to-payer, hitting our node as a target means we should stop
                        // traversing the graph and arrange the path out of what we found.
                        if node_id == our_node_id {
-                               let mut new_entry = dist.remove(&our_node_id).unwrap();
+                               let mut new_entry = dist[payer_node_counter as usize].take().unwrap();
                                let mut ordered_hops: Vec<(PathBuildingHop, NodeFeatures)> = vec!((new_entry.clone(), default_node_features.clone()));
 
                                'path_walk: loop {
                                        let mut features_set = false;
-                                       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) {
+                                       let candidate = &ordered_hops.last().unwrap().0.candidate;
+                                       let target = candidate.target().unwrap_or(maybe_dummy_payee_node_id);
+                                       let target_node_counter = candidate.target_node_counter();
+                                       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(CandidateFirstHop { details: last_hop_details, .. })
                                                                = ordered_hops.last().unwrap().0.candidate
                                                        {
                                                                if details.get_outbound_payment_scid() == last_hop_details.get_outbound_payment_scid() {
@@ -2576,11 +2888,12 @@ where L::Target: Logger {
                                        // 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.
-                                       if target == maybe_dummy_payee_node_id {
+                                       if target_node_counter.is_none() {
                                                break 'path_walk;
                                        }
+                                       if target_node_counter == Some(payee_node_counter) { break 'path_walk; }
 
-                                       new_entry = match dist.remove(&target) {
+                                       new_entry = match dist[target_node_counter.unwrap() as usize].take() {
                                                Some(payment_hop) => payment_hop,
                                                // We can't arrive at None because, if we ever add an entry to targets,
                                                // we also fill in the entry in dist (see add_entry!).
@@ -2814,12 +3127,12 @@ 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
@@ -3049,7 +3362,7 @@ 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, CandidatePublicHop};
        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;
@@ -6780,11 +7093,11 @@ mod tests {
        #[test]
        #[cfg(not(feature = "no-std"))]
        fn generate_routes() {
-               use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
+               use crate::routing::scoring::ProbabilisticScoringFeeParameters;
 
                let logger = ln_test_utils::TestLogger::new();
-               let graph = match super::bench_utils::read_network_graph(&logger) {
-                       Ok(f) => f,
+               let (graph, mut scorer) = match super::bench_utils::read_graph_scorer(&logger) {
+                       Ok(res) => res,
                        Err(e) => {
                                eprintln!("{}", e);
                                return;
@@ -6792,7 +7105,6 @@ mod tests {
                };
 
                let params = ProbabilisticScoringFeeParameters::default();
-               let mut scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &graph, &logger);
                let features = super::Bolt11InvoiceFeatures::empty();
 
                super::bench_utils::generate_test_routes(&graph, &mut scorer, &params, features, random_init_seed(), 0, 2);
@@ -6801,11 +7113,11 @@ mod tests {
        #[test]
        #[cfg(not(feature = "no-std"))]
        fn generate_routes_mpp() {
-               use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
+               use crate::routing::scoring::ProbabilisticScoringFeeParameters;
 
                let logger = ln_test_utils::TestLogger::new();
-               let graph = match super::bench_utils::read_network_graph(&logger) {
-                       Ok(f) => f,
+               let (graph, mut scorer) = match super::bench_utils::read_graph_scorer(&logger) {
+                       Ok(res) => res,
                        Err(e) => {
                                eprintln!("{}", e);
                                return;
@@ -6813,7 +7125,6 @@ mod tests {
                };
 
                let params = ProbabilisticScoringFeeParameters::default();
-               let mut scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &graph, &logger);
                let features = channelmanager::provided_bolt11_invoice_features(&UserConfig::default());
 
                super::bench_utils::generate_test_routes(&graph, &mut scorer, &params, features, random_init_seed(), 0, 2);
@@ -6825,8 +7136,8 @@ mod tests {
                use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
 
                let logger = ln_test_utils::TestLogger::new();
-               let graph = match super::bench_utils::read_network_graph(&logger) {
-                       Ok(f) => f,
+               let (graph, mut scorer) = match super::bench_utils::read_graph_scorer(&logger) {
+                       Ok(res) => res,
                        Err(e) => {
                                eprintln!("{}", e);
                                return;
@@ -6834,7 +7145,7 @@ mod tests {
                };
 
                let params = ProbabilisticScoringFeeParameters::default();
-               let mut scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &graph, &logger);
+               let mut scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &*graph, &logger);
                let features = channelmanager::provided_bolt11_invoice_features(&UserConfig::default());
 
                super::bench_utils::generate_test_routes(&graph, &mut scorer, &params, features, random_init_seed(), 1_000_000, 2);
@@ -6863,10 +7174,10 @@ 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(CandidatePublicHop {
                        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
@@ -8171,46 +8482,63 @@ pub(crate) mod bench_utils {
        use crate::ln::channelmanager::{self, ChannelCounterparty, ChannelDetails};
        use crate::ln::features::Bolt11InvoiceFeatures;
        use crate::routing::gossip::NetworkGraph;
+       use crate::routing::scoring::ProbabilisticScorer;
        use crate::util::config::UserConfig;
        use crate::util::ser::ReadableArgs;
        use crate::util::test_utils::TestLogger;
+       use crate::sync::Arc;
 
        /// Tries to open a network graph file, or panics with a URL to fetch it.
-       pub(crate) fn get_route_file() -> Result<std::fs::File, &'static str> {
-               let res = File::open("net_graph-2023-01-18.bin") // By default we're run in RL/lightning
-                       .or_else(|_| File::open("lightning/net_graph-2023-01-18.bin")) // We may be run manually in RL/
-                       .or_else(|_| { // Fall back to guessing based on the binary location
-                               // path is likely something like .../rust-lightning/target/debug/deps/lightning-...
-                               let mut path = std::env::current_exe().unwrap();
-                               path.pop(); // lightning-...
-                               path.pop(); // deps
-                               path.pop(); // debug
-                               path.pop(); // target
-                               path.push("lightning");
-                               path.push("net_graph-2023-01-18.bin");
-                               File::open(path)
-                       })
-                       .or_else(|_| { // Fall back to guessing based on the binary location for a subcrate
-                               // path is likely something like .../rust-lightning/bench/target/debug/deps/bench..
-                               let mut path = std::env::current_exe().unwrap();
-                               path.pop(); // bench...
-                               path.pop(); // deps
-                               path.pop(); // debug
-                               path.pop(); // target
-                               path.pop(); // bench
-                               path.push("lightning");
-                               path.push("net_graph-2023-01-18.bin");
-                               File::open(path)
-                       })
-               .map_err(|_| "Please fetch https://bitcoin.ninja/ldk-net_graph-v0.0.113-2023-01-18.bin and place it at lightning/net_graph-2023-01-18.bin");
+       pub(crate) fn get_graph_scorer_file() -> Result<(std::fs::File, std::fs::File), &'static str> {
+               let load_file = |fname, err_str| {
+                       File::open(fname) // By default we're run in RL/lightning
+                               .or_else(|_| File::open(&format!("lightning/{}", fname))) // We may be run manually in RL/
+                               .or_else(|_| { // Fall back to guessing based on the binary location
+                                       // path is likely something like .../rust-lightning/target/debug/deps/lightning-...
+                                       let mut path = std::env::current_exe().unwrap();
+                                       path.pop(); // lightning-...
+                                       path.pop(); // deps
+                                       path.pop(); // debug
+                                       path.pop(); // target
+                                       path.push("lightning");
+                                       path.push(fname);
+                                       File::open(path)
+                               })
+                               .or_else(|_| { // Fall back to guessing based on the binary location for a subcrate
+                                       // path is likely something like .../rust-lightning/bench/target/debug/deps/bench..
+                                       let mut path = std::env::current_exe().unwrap();
+                                       path.pop(); // bench...
+                                       path.pop(); // deps
+                                       path.pop(); // debug
+                                       path.pop(); // target
+                                       path.pop(); // bench
+                                       path.push("lightning");
+                                       path.push(fname);
+                                       File::open(path)
+                               })
+                       .map_err(|_| err_str)
+               };
+               let graph_res = load_file(
+                       "net_graph-2023-12-10.bin",
+                       "Please fetch https://bitcoin.ninja/ldk-net_graph-v0.0.118-2023-12-10.bin and place it at lightning/net_graph-2023-12-10.bin"
+               );
+               let scorer_res = load_file(
+                       "scorer-2023-12-10.bin",
+                       "Please fetch https://bitcoin.ninja/ldk-scorer-v0.0.118-2023-12-10.bin and place it at scorer-2023-12-10.bin"
+               );
                #[cfg(require_route_graph_test)]
-               return Ok(res.unwrap());
+               return Ok((graph_res.unwrap(), scorer_res.unwrap()));
                #[cfg(not(require_route_graph_test))]
-               return res;
+               return Ok((graph_res?, scorer_res?));
        }
 
-       pub(crate) fn read_network_graph(logger: &TestLogger) -> Result<NetworkGraph<&TestLogger>, &'static str> {
-               get_route_file().map(|mut f| NetworkGraph::read(&mut f, logger).unwrap())
+       pub(crate) fn read_graph_scorer(logger: &TestLogger)
+       -> Result<(Arc<NetworkGraph<&TestLogger>>, ProbabilisticScorer<Arc<NetworkGraph<&TestLogger>>, &TestLogger>), &'static str> {
+               let (mut graph_file, mut scorer_file) = get_graph_scorer_file()?;
+               let graph = Arc::new(NetworkGraph::read(&mut graph_file, logger).unwrap());
+               let scorer_args = (Default::default(), Arc::clone(&graph), logger);
+               let scorer = ProbabilisticScorer::read(&mut scorer_file, scorer_args).unwrap();
+               Ok((graph, scorer))
        }
 
        pub(crate) fn payer_pubkey() -> PublicKey {
@@ -8270,9 +8598,7 @@ pub(crate) mod bench_utils {
 
                let nodes = graph.read_only().nodes().clone();
                let mut route_endpoints = Vec::new();
-               // Fetch 1.5x more routes than we need as after we do some scorer updates we may end up
-               // with some routes we picked being un-routable.
-               for _ in 0..route_count * 3 / 2 {
+               for _ in 0..route_count {
                        loop {
                                seed = seed.overflowing_mul(6364136223846793005).0.overflowing_add(1).0;
                                let src = PublicKey::from_slice(nodes.unordered_keys()
@@ -8290,37 +8616,6 @@ pub(crate) mod bench_utils {
                                        get_route(&payer, &route_params, &graph.read_only(), Some(&[&first_hop]),
                                                &TestLogger::new(), scorer, score_params, &random_seed_bytes).is_ok();
                                if path_exists {
-                                       // ...and seed the scorer with success and failure data...
-                                       seed = seed.overflowing_mul(6364136223846793005).0.overflowing_add(1).0;
-                                       let mut score_amt = seed % 1_000_000_000;
-                                       loop {
-                                               // Generate fail/success paths for a wider range of potential amounts with
-                                               // MPP enabled to give us a chance to apply penalties for more potential
-                                               // routes.
-                                               let mpp_features = channelmanager::provided_bolt11_invoice_features(&UserConfig::default());
-                                               let params = PaymentParameters::from_node_id(dst, 42)
-                                                       .with_bolt11_features(mpp_features).unwrap();
-                                               let route_params = RouteParameters::from_payment_params_and_value(
-                                                       params.clone(), score_amt);
-                                               let route_res = get_route(&payer, &route_params, &graph.read_only(),
-                                                       Some(&[&first_hop]), &TestLogger::new(), scorer, score_params,
-                                                       &random_seed_bytes);
-                                               if let Ok(route) = route_res {
-                                                       for path in route.paths {
-                                                               if seed & 0x80 == 0 {
-                                                                       scorer.payment_path_successful(&path);
-                                                               } else {
-                                                                       let short_channel_id = path.hops[path.hops.len() / 2].short_channel_id;
-                                                                       scorer.payment_path_failed(&path, short_channel_id);
-                                                               }
-                                                               seed = seed.overflowing_mul(6364136223846793005).0.overflowing_add(1).0;
-                                                       }
-                                                       break;
-                                               }
-                                               // If we couldn't find a path with a higer amount, reduce and try again.
-                                               score_amt /= 100;
-                                       }
-
                                        route_endpoints.push((first_hop, params, amt_msat));
                                        break;
                                }
@@ -8350,7 +8645,7 @@ pub mod benches {
        use crate::ln::channelmanager;
        use crate::ln::features::Bolt11InvoiceFeatures;
        use crate::routing::gossip::NetworkGraph;
-       use crate::routing::scoring::{FixedPenaltyScorer, ProbabilisticScorer, ProbabilisticScoringFeeParameters, ProbabilisticScoringDecayParameters};
+       use crate::routing::scoring::{FixedPenaltyScorer, ProbabilisticScoringFeeParameters};
        use crate::util::config::UserConfig;
        use crate::util::logger::{Logger, Record};
        use crate::util::test_utils::TestLogger;
@@ -8364,7 +8659,7 @@ pub mod benches {
 
        pub fn generate_routes_with_zero_penalty_scorer(bench: &mut Criterion) {
                let logger = TestLogger::new();
-               let network_graph = bench_utils::read_network_graph(&logger).unwrap();
+               let (network_graph, _) = bench_utils::read_graph_scorer(&logger).unwrap();
                let scorer = FixedPenaltyScorer::with_penalty(0);
                generate_routes(bench, &network_graph, scorer, &Default::default(),
                        Bolt11InvoiceFeatures::empty(), 0, "generate_routes_with_zero_penalty_scorer");
@@ -8372,7 +8667,7 @@ pub mod benches {
 
        pub fn generate_mpp_routes_with_zero_penalty_scorer(bench: &mut Criterion) {
                let logger = TestLogger::new();
-               let network_graph = bench_utils::read_network_graph(&logger).unwrap();
+               let (network_graph, _) = bench_utils::read_graph_scorer(&logger).unwrap();
                let scorer = FixedPenaltyScorer::with_penalty(0);
                generate_routes(bench, &network_graph, scorer, &Default::default(),
                        channelmanager::provided_bolt11_invoice_features(&UserConfig::default()), 0,
@@ -8381,18 +8676,16 @@ pub mod benches {
 
        pub fn generate_routes_with_probabilistic_scorer(bench: &mut Criterion) {
                let logger = TestLogger::new();
-               let network_graph = bench_utils::read_network_graph(&logger).unwrap();
+               let (network_graph, scorer) = bench_utils::read_graph_scorer(&logger).unwrap();
                let params = ProbabilisticScoringFeeParameters::default();
-               let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
                generate_routes(bench, &network_graph, scorer, &params, Bolt11InvoiceFeatures::empty(), 0,
                        "generate_routes_with_probabilistic_scorer");
        }
 
        pub fn generate_mpp_routes_with_probabilistic_scorer(bench: &mut Criterion) {
                let logger = TestLogger::new();
-               let network_graph = bench_utils::read_network_graph(&logger).unwrap();
+               let (network_graph, scorer) = bench_utils::read_graph_scorer(&logger).unwrap();
                let params = ProbabilisticScoringFeeParameters::default();
-               let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
                generate_routes(bench, &network_graph, scorer, &params,
                        channelmanager::provided_bolt11_invoice_features(&UserConfig::default()), 0,
                        "generate_mpp_routes_with_probabilistic_scorer");
@@ -8400,9 +8693,8 @@ pub mod benches {
 
        pub fn generate_large_mpp_routes_with_probabilistic_scorer(bench: &mut Criterion) {
                let logger = TestLogger::new();
-               let network_graph = bench_utils::read_network_graph(&logger).unwrap();
+               let (network_graph, scorer) = bench_utils::read_graph_scorer(&logger).unwrap();
                let params = ProbabilisticScoringFeeParameters::default();
-               let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
                generate_routes(bench, &network_graph, scorer, &params,
                        channelmanager::provided_bolt11_invoice_features(&UserConfig::default()), 100_000_000,
                        "generate_large_mpp_routes_with_probabilistic_scorer");
@@ -8410,11 +8702,9 @@ pub mod benches {
 
        pub fn generate_routes_with_nonlinear_probabilistic_scorer(bench: &mut Criterion) {
                let logger = TestLogger::new();
-               let network_graph = bench_utils::read_network_graph(&logger).unwrap();
+               let (network_graph, scorer) = bench_utils::read_graph_scorer(&logger).unwrap();
                let mut params = ProbabilisticScoringFeeParameters::default();
                params.linear_success_probability = false;
-               let scorer = ProbabilisticScorer::new(
-                       ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
                generate_routes(bench, &network_graph, scorer, &params,
                        channelmanager::provided_bolt11_invoice_features(&UserConfig::default()), 0,
                        "generate_routes_with_nonlinear_probabilistic_scorer");
@@ -8422,11 +8712,9 @@ pub mod benches {
 
        pub fn generate_mpp_routes_with_nonlinear_probabilistic_scorer(bench: &mut Criterion) {
                let logger = TestLogger::new();
-               let network_graph = bench_utils::read_network_graph(&logger).unwrap();
+               let (network_graph, scorer) = bench_utils::read_graph_scorer(&logger).unwrap();
                let mut params = ProbabilisticScoringFeeParameters::default();
                params.linear_success_probability = false;
-               let scorer = ProbabilisticScorer::new(
-                       ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
                generate_routes(bench, &network_graph, scorer, &params,
                        channelmanager::provided_bolt11_invoice_features(&UserConfig::default()), 0,
                        "generate_mpp_routes_with_nonlinear_probabilistic_scorer");
@@ -8434,11 +8722,9 @@ pub mod benches {
 
        pub fn generate_large_mpp_routes_with_nonlinear_probabilistic_scorer(bench: &mut Criterion) {
                let logger = TestLogger::new();
-               let network_graph = bench_utils::read_network_graph(&logger).unwrap();
+               let (network_graph, scorer) = bench_utils::read_graph_scorer(&logger).unwrap();
                let mut params = ProbabilisticScoringFeeParameters::default();
                params.linear_success_probability = false;
-               let scorer = ProbabilisticScorer::new(
-                       ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
                generate_routes(bench, &network_graph, scorer, &params,
                        channelmanager::provided_bolt11_invoice_features(&UserConfig::default()), 100_000_000,
                        "generate_large_mpp_routes_with_nonlinear_probabilistic_scorer");
@@ -8449,14 +8735,23 @@ pub mod benches {
                score_params: &S::ScoreParams, features: Bolt11InvoiceFeatures, starting_amount: u64,
                bench_name: &'static str,
        ) {
-               let payer = bench_utils::payer_pubkey();
-               let keys_manager = KeysManager::new(&[0u8; 32], 42, 42);
-               let random_seed_bytes = keys_manager.get_secure_random_bytes();
-
                // First, get 100 (source, destination) pairs for which route-getting actually succeeds...
                let route_endpoints = bench_utils::generate_test_routes(graph, &mut scorer, score_params, features, 0xdeadbeef, starting_amount, 50);
 
                // ...then benchmark finding paths between the nodes we learned.
+               do_route_bench(bench, graph, scorer, score_params, bench_name, route_endpoints);
+       }
+
+       #[inline(never)]
+       fn do_route_bench<S: ScoreLookUp + ScoreUpdate>(
+               bench: &mut Criterion, graph: &NetworkGraph<&TestLogger>, scorer: S,
+               score_params: &S::ScoreParams, bench_name: &'static str,
+               route_endpoints: Vec<(ChannelDetails, PaymentParameters, u64)>,
+       ) {
+               let payer = bench_utils::payer_pubkey();
+               let keys_manager = KeysManager::new(&[0u8; 32], 42, 42);
+               let random_seed_bytes = keys_manager.get_secure_random_bytes();
+
                let mut idx = 0;
                bench.bench_function(bench_name, |b| b.iter(|| {
                        let (first_hop, params, amt) = &route_endpoints[idx % route_endpoints.len()];