Cache introduction_node_id lookup in get_route
[rust-lightning] / lightning / src / routing / router.rs
index 52678c42c8eb337295492a0c7e54b630d2c5c423..b25820eca26804d11e5fcdef68d002d1d8aa520e 100644 (file)
@@ -9,55 +9,59 @@
 
 //! The router finds paths within a [`NetworkGraph`] for a payment.
 
-use bitcoin::secp256k1::PublicKey;
-use bitcoin::hashes::Hash;
-use bitcoin::hashes::sha256::Hash as Sha256;
+use bitcoin::secp256k1::{PublicKey, Secp256k1, self};
 
-use crate::blinded_path::{BlindedHop, BlindedPath};
+use crate::blinded_path::{BlindedHop, BlindedPath, Direction, IntroductionNode};
+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::channelmanager::{ChannelDetails, PaymentId, MIN_FINAL_CLTV_EXPIRY_DELTA};
+use crate::ln::features::{BlindedHopFeatures, Bolt11InvoiceFeatures, Bolt12InvoiceFeatures, ChannelFeatures, NodeFeatures};
 use crate::ln::msgs::{DecodeError, ErrorAction, LightningError, MAX_VALUE_MSAT};
 use crate::offers::invoice::{BlindedPayInfo, Bolt12Invoice};
+use crate::onion_message::messenger::{DefaultMessageRouter, Destination, MessageRouter, OnionMessagePath};
 use crate::routing::gossip::{DirectedChannelInfo, EffectiveCapacity, ReadOnlyNetworkGraph, NetworkGraph, NodeId, RoutingFees};
 use crate::routing::scoring::{ChannelUsage, LockableScore, ScoreLookUp};
+use crate::sign::EntropySource;
 use crate::util::ser::{Writeable, Readable, ReadableArgs, Writer};
 use crate::util::logger::{Level, Logger};
-use crate::util::chacha20::ChaCha20;
+use crate::crypto::chacha20::ChaCha20;
 
 use crate::io;
 use crate::prelude::*;
-use crate::sync::Mutex;
 use alloc::collections::BinaryHeap;
 use core::{cmp, fmt};
 use core::ops::Deref;
 
 /// A [`Router`] implemented using [`find_route`].
-pub struct DefaultRouter<G: Deref<Target = NetworkGraph<L>>, L: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> where
+pub struct DefaultRouter<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, ES: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> where
        L::Target: Logger,
        S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,
+       ES::Target: EntropySource,
 {
        network_graph: G,
        logger: L,
-       random_seed_bytes: Mutex<[u8; 32]>,
+       entropy_source: ES,
        scorer: S,
-       score_params: SP
+       score_params: SP,
+       message_router: DefaultMessageRouter<G, L, ES>,
 }
 
-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, ES: Deref + Clone, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> DefaultRouter<G, L, ES, S, SP, Sc> where
        L::Target: Logger,
        S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,
+       ES::Target: EntropySource,
 {
        /// Creates a new router.
-       pub fn new(network_graph: G, logger: L, random_seed_bytes: [u8; 32], scorer: S, score_params: SP) -> Self {
-               let random_seed_bytes = Mutex::new(random_seed_bytes);
-               Self { network_graph, logger, random_seed_bytes, scorer, score_params }
+       pub fn new(network_graph: G, logger: L, entropy_source: ES, scorer: S, score_params: SP) -> Self {
+               let message_router = DefaultMessageRouter::new(network_graph.clone(), entropy_source.clone());
+               Self { network_graph, logger, entropy_source, scorer, score_params, message_router }
        }
 }
 
-impl< G: Deref<Target = NetworkGraph<L>>, L: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> Router for DefaultRouter<G, L, S, SP, Sc> where
+impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, ES: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> Router for DefaultRouter<G, L, ES, S, SP, Sc> where
        L::Target: Logger,
        S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,
+       ES::Target: EntropySource,
 {
        fn find_route(
                &self,
@@ -66,11 +70,7 @@ impl< G: Deref<Target = NetworkGraph<L>>, L: Deref, S: Deref, SP: Sized, Sc: Sco
                first_hops: Option<&[&ChannelDetails]>,
                inflight_htlcs: InFlightHtlcs
        ) -> Result<Route, LightningError> {
-               let random_seed_bytes = {
-                       let mut locked_random_seed_bytes = self.random_seed_bytes.lock().unwrap();
-                       *locked_random_seed_bytes = Sha256::hash(&*locked_random_seed_bytes).to_byte_array();
-                       *locked_random_seed_bytes
-               };
+               let random_seed_bytes = self.entropy_source.get_secure_random_bytes();
                find_route(
                        payer, params, &self.network_graph, first_hops, &*self.logger,
                        &ScorerAccountingForInFlightHtlcs::new(self.scorer.read_lock(), &inflight_htlcs),
@@ -78,10 +78,106 @@ impl< G: Deref<Target = NetworkGraph<L>>, L: Deref, S: Deref, SP: Sized, Sc: Sco
                        &random_seed_bytes
                )
        }
+
+       fn create_blinded_payment_paths<
+               T: secp256k1::Signing + secp256k1::Verification
+       > (
+               &self, recipient: PublicKey, first_hops: Vec<ChannelDetails>, tlvs: ReceiveTlvs,
+               amount_msats: u64, secp_ctx: &Secp256k1<T>
+       ) -> Result<Vec<(BlindedPayInfo, BlindedPath)>, ()> {
+               // Limit the number of blinded paths that are computed.
+               const MAX_PAYMENT_PATHS: usize = 3;
+
+               // 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) => match forwarding_info.try_into() {
+                                               Ok(payment_relay) => payment_relay,
+                                               Err(()) => return None,
+                                       },
+                                       None => return None,
+                               };
+
+                               let cltv_expiry_delta = payment_relay.cltv_expiry_delta as u32;
+                               let payment_constraints = PaymentConstraints {
+                                       max_cltv_expiry: tlvs.payment_constraints.max_cltv_expiry + cltv_expiry_delta,
+                                       htlc_minimum_msat: details.inbound_htlc_minimum_msat.unwrap_or(0),
+                               };
+                               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, MIN_FINAL_CLTV_EXPIRY_DELTA,
+                                       &*self.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, MIN_FINAL_CLTV_EXPIRY_DELTA, &*self.entropy_source, secp_ctx
+                                       ).map(|path| vec![path])
+                               } else {
+                                       Err(())
+                               }
+                       },
+               }
+       }
+}
+
+impl< G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, ES: Deref, S: Deref, SP: Sized, Sc: ScoreLookUp<ScoreParams = SP>> MessageRouter for DefaultRouter<G, L, ES, S, SP, Sc> where
+       L::Target: Logger,
+       S::Target: for <'a> LockableScore<'a, ScoreLookUp = Sc>,
+       ES::Target: EntropySource,
+{
+       fn find_path(
+               &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
+       ) -> Result<OnionMessagePath, ()> {
+               self.message_router.find_path(sender, peers, destination)
+       }
+
+       fn create_blinded_paths<
+               T: secp256k1::Signing + secp256k1::Verification
+       > (
+               &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
+       ) -> Result<Vec<BlindedPath>, ()> {
+               self.message_router.create_blinded_paths(recipient, peers, 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 +201,16 @@ 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<
+               T: secp256k1::Signing + secp256k1::Verification
+       > (
+               &self, recipient: PublicKey, first_hops: Vec<ChannelDetails>, tlvs: ReceiveTlvs,
+               amount_msats: u64, secp_ctx: &Secp256k1<T>
+       ) -> Result<Vec<(BlindedPayInfo, BlindedPath)>, ()>;
 }
 
 /// [`ScoreLookUp`] implementation that factors in in-flight HTLC liquidity.
@@ -168,7 +274,7 @@ pub struct InFlightHtlcs(
 
 impl InFlightHtlcs {
        /// Constructs an empty `InFlightHtlcs`.
-       pub fn new() -> Self { InFlightHtlcs(HashMap::new()) }
+       pub fn new() -> Self { InFlightHtlcs(new_hash_map()) }
 
        /// Takes in a path with payer's node id and adds the path's details to `InFlightHtlcs`.
        pub fn process_path(&mut self, path: &Path, payer_node_id: PublicKey) {
@@ -399,20 +505,20 @@ impl Writeable for Route {
                write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
                (self.paths.len() as u64).write(writer)?;
                let mut blinded_tails = Vec::new();
-               for path in self.paths.iter() {
+               for (idx, path) in self.paths.iter().enumerate() {
                        (path.hops.len() as u8).write(writer)?;
-                       for (idx, hop) in path.hops.iter().enumerate() {
+                       for hop in path.hops.iter() {
                                hop.write(writer)?;
-                               if let Some(blinded_tail) = &path.blinded_tail {
-                                       if blinded_tails.is_empty() {
-                                               blinded_tails = Vec::with_capacity(path.hops.len());
-                                               for _ in 0..idx {
-                                                       blinded_tails.push(None);
-                                               }
-                                       }
-                                       blinded_tails.push(Some(blinded_tail));
-                               } else if !blinded_tails.is_empty() { blinded_tails.push(None); }
                        }
+                       if let Some(blinded_tail) = &path.blinded_tail {
+                               if blinded_tails.is_empty() {
+                                       blinded_tails = Vec::with_capacity(path.hops.len());
+                                       for _ in 0..idx {
+                                               blinded_tails.push(None);
+                                       }
+                               }
+                               blinded_tails.push(Some(blinded_tail));
+                       } else if !blinded_tails.is_empty() { blinded_tails.push(None); }
                }
                write_tlv_fields!(writer, {
                        // For compatibility with LDK versions prior to 0.0.117, we take the individual
@@ -420,7 +526,7 @@ impl Writeable for Route {
                        (1, self.route_params.as_ref().map(|p| &p.payment_params), option),
                        (2, blinded_tails, optional_vec),
                        (3, self.route_params.as_ref().map(|p| p.final_value_msat), option),
-                       (5, self.route_params.as_ref().map(|p| p.max_total_routing_fee_msat), option),
+                       (5, self.route_params.as_ref().and_then(|p| p.max_total_routing_fee_msat), option),
                });
                Ok(())
        }
@@ -597,6 +703,11 @@ pub struct PaymentParameters {
        /// payment to fail. Future attempts for the same payment shouldn't be relayed through any of
        /// these SCIDs.
        pub previously_failed_channels: Vec<u64>,
+
+       /// A list of indices corresponding to blinded paths in [`Payee::Blinded::route_hints`] which this
+       /// payment was previously attempted over and which caused the payment to fail. Future attempts
+       /// for the same payment shouldn't be relayed through any of these blinded paths.
+       pub previously_failed_blinded_path_idxs: Vec<u64>,
 }
 
 impl Writeable for PaymentParameters {
@@ -618,6 +729,7 @@ impl Writeable for PaymentParameters {
                        (7, self.previously_failed_channels, required_vec),
                        (8, *blinded_hints, optional_vec),
                        (9, self.payee.final_cltv_expiry_delta(), option),
+                       (11, self.previously_failed_blinded_path_idxs, required_vec),
                });
                Ok(())
        }
@@ -636,6 +748,7 @@ impl ReadableArgs<u32> for PaymentParameters {
                        (7, previously_failed_channels, optional_vec),
                        (8, blinded_route_hints, optional_vec),
                        (9, final_cltv_expiry_delta, (default_value, default_final_cltv_expiry_delta)),
+                       (11, previously_failed_blinded_path_idxs, optional_vec),
                });
                let blinded_route_hints = blinded_route_hints.unwrap_or(vec![]);
                let payee = if blinded_route_hints.len() != 0 {
@@ -659,6 +772,7 @@ impl ReadableArgs<u32> for PaymentParameters {
                        max_channel_saturation_power_of_half: _init_tlv_based_struct_field!(max_channel_saturation_power_of_half, (default_value, unused)),
                        expiry_time,
                        previously_failed_channels: previously_failed_channels.unwrap_or(Vec::new()),
+                       previously_failed_blinded_path_idxs: previously_failed_blinded_path_idxs.unwrap_or(Vec::new()),
                })
        }
 }
@@ -677,6 +791,7 @@ impl PaymentParameters {
                        max_path_count: DEFAULT_MAX_PATH_COUNT,
                        max_channel_saturation_power_of_half: DEFAULT_MAX_CHANNEL_SATURATION_POW_HALF,
                        previously_failed_channels: Vec::new(),
+                       previously_failed_blinded_path_idxs: Vec::new(),
                }
        }
 
@@ -715,6 +830,7 @@ impl PaymentParameters {
                        max_path_count: DEFAULT_MAX_PATH_COUNT,
                        max_channel_saturation_power_of_half: DEFAULT_MAX_CHANNEL_SATURATION_POW_HALF,
                        previously_failed_channels: Vec::new(),
+                       previously_failed_blinded_path_idxs: Vec::new(),
                }
        }
 
@@ -790,6 +906,19 @@ impl PaymentParameters {
        pub fn with_max_channel_saturation_power_of_half(self, max_channel_saturation_power_of_half: u8) -> Self {
                Self { max_channel_saturation_power_of_half, ..self }
        }
+
+       pub(crate) fn insert_previously_failed_blinded_path(&mut self, failed_blinded_tail: &BlindedTail) {
+               let mut found_blinded_tail = false;
+               for (idx, (_, path)) in self.payee.blinded_route_hints().iter().enumerate() {
+                       if failed_blinded_tail.hops == path.blinded_hops &&
+                               failed_blinded_tail.blinding_point == path.blinding_point
+                       {
+                               self.previously_failed_blinded_path_idxs.push(idx as u64);
+                               found_blinded_tail = true;
+                       }
+               }
+               debug_assert!(found_blinded_tail);
+       }
 }
 
 /// The recipient of a payment, differing based on whether they've hidden their identity with route
@@ -857,7 +986,7 @@ impl Payee {
                        _ => None,
                }
        }
-       fn blinded_route_hints(&self) -> &[(BlindedPayInfo, BlindedPath)] {
+       pub(crate) fn blinded_route_hints(&self) -> &[(BlindedPayInfo, BlindedPath)] {
                match self {
                        Self::Blinded { route_hints, .. } => &route_hints[..],
                        Self::Clear { .. } => &[]
@@ -968,33 +1097,24 @@ impl_writeable_tlv_based!(RouteHintHop, {
 });
 
 #[derive(Eq, PartialEq)]
+#[repr(align(64))] // Force the size to 64 bytes
 struct RouteGraphNode {
        node_id: NodeId,
-       lowest_fee_to_node: u64,
-       total_cltv_delta: u32,
+       score: u64,
        // The maximum value a yet-to-be-constructed payment path might flow through this node.
        // This value is upper-bounded by us by:
        // - how much is needed for a path being constructed
        // - how much value can channels following this node (up to the destination) can contribute,
        //   considering their capacity and fees
        value_contribution_msat: u64,
-       /// The effective htlc_minimum_msat at this hop. If a later hop on the path had a higher HTLC
-       /// minimum, we use it, plus the fees required at each earlier hop to meet it.
-       path_htlc_minimum_msat: u64,
-       /// All penalties incurred from this hop on the way to the destination, as calculated using
-       /// channel scoring.
-       path_penalty_msat: u64,
+       total_cltv_delta: u32,
        /// The number of hops walked up to this node.
        path_length_to_node: u8,
 }
 
 impl cmp::Ord for RouteGraphNode {
        fn cmp(&self, other: &RouteGraphNode) -> cmp::Ordering {
-               let other_score = cmp::max(other.lowest_fee_to_node, other.path_htlc_minimum_msat)
-                       .saturating_add(other.path_penalty_msat);
-               let self_score = cmp::max(self.lowest_fee_to_node, self.path_htlc_minimum_msat)
-                       .saturating_add(self.path_penalty_msat);
-               other_score.cmp(&self_score).then_with(|| other.node_id.cmp(&self.node_id))
+               other.score.cmp(&self.score).then_with(|| other.node_id.cmp(&self.node_id))
        }
 }
 
@@ -1004,6 +1124,102 @@ 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 FirstHopCandidate<'a> {
+       /// Channel details of the first hop
+       ///
+       /// [`ChannelDetails::get_outbound_payment_scid`] MUST be `Some` (indicating the channel
+       /// has been funded and is able to pay), and accessor methods may panic otherwise.
+       ///
+       /// [`find_route`] validates this prior to constructing a [`CandidateRouteHop`].
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub details: &'a ChannelDetails,
+       /// The node id of the payer, which is also the source side of this candidate route hop.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub payer_node_id: &'a NodeId,
+}
+
+/// A [`CandidateRouteHop::PublicHop`] entry.
+#[derive(Clone, Debug)]
+pub struct PublicHopCandidate<'a> {
+       /// Information about the channel, including potentially its capacity and
+       /// direction-specific information.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub info: DirectedChannelInfo<'a>,
+       /// The short channel ID of the channel, i.e. the identifier by which we refer to this
+       /// channel.
+       pub short_channel_id: u64,
+}
+
+/// A [`CandidateRouteHop::PrivateHop`] entry.
+#[derive(Clone, Debug)]
+pub struct PrivateHopCandidate<'a> {
+       /// Information about the private hop communicated via BOLT 11.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub hint: &'a RouteHintHop,
+       /// Node id of the next hop in BOLT 11 route hint.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub target_node_id: &'a NodeId
+}
+
+/// A [`CandidateRouteHop::Blinded`] entry.
+#[derive(Clone, Debug)]
+pub struct BlindedPathCandidate<'a> {
+       /// The node id of the introduction node, resolved from either the [`NetworkGraph`] or first
+       /// hops.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressible in most languages.
+       pub source_node_id: &'a NodeId,
+       /// Information about the blinded path including the fee, HTLC amount limits, and
+       /// cryptographic material required to build an HTLC through the given path.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub hint: &'a (BlindedPayInfo, BlindedPath),
+       /// Index of the hint in the original list of blinded hints.
+       ///
+       /// This is used to cheaply uniquely identify this blinded path, even though we don't have
+       /// a short channel ID for this hop.
+       hint_idx: usize,
+}
+
+/// A [`CandidateRouteHop::OneHopBlinded`] entry.
+#[derive(Clone, Debug)]
+pub struct OneHopBlindedPathCandidate<'a> {
+       /// The node id of the introduction node, resolved from either the [`NetworkGraph`] or first
+       /// hops.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressible in most languages.
+       pub source_node_id: &'a NodeId,
+       /// Information about the blinded path including the fee, HTLC amount limits, and
+       /// cryptographic material required to build an HTLC terminating with the given path.
+       ///
+       /// Note that the [`BlindedPayInfo`] is ignored here.
+       ///
+       /// This is not exported to bindings users as lifetimes are not expressable in most languages.
+       pub hint: &'a (BlindedPayInfo, BlindedPath),
+       /// Index of the hint in the original list of blinded hints.
+       ///
+       /// This is used to cheaply uniquely identify this blinded path, even though we don't have
+       /// a short channel ID for this hop.
+       hint_idx: usize,
+}
+
 /// A wrapper around the various hop representations.
 ///
 /// Can be used to examine the properties of a hop,
@@ -1011,36 +1227,14 @@ impl cmp::PartialOrd for RouteGraphNode {
 #[derive(Clone, Debug)]
 pub enum CandidateRouteHop<'a> {
        /// A hop from the payer, where the outbound liquidity is known.
-       FirstHop {
-               /// Channel details of the first hop
-               ///
-               /// [`ChannelDetails::get_outbound_payment_scid`] MUST be `Some` (indicating the channel
-               /// has been funded and is able to pay), and accessor methods may panic otherwise.
-               ///
-               /// [`find_route`] validates this prior to constructing a [`CandidateRouteHop`].
-               details: &'a ChannelDetails,
-               /// The node id of the payer, which is also the source side of this candidate route hop.
-               payer_node_id: &'a NodeId,
-       },
+       FirstHop(FirstHopCandidate<'a>),
        /// A hop found in the [`ReadOnlyNetworkGraph`].
-       PublicHop {
-               /// Information about the channel, including potentially its capacity and
-               /// direction-specific information.
-               info: DirectedChannelInfo<'a>,
-               /// The short channel ID of the channel, i.e. the identifier by which we refer to this
-               /// channel.
-               short_channel_id: u64,
-       },
+       PublicHop(PublicHopCandidate<'a>),
        /// A private hop communicated by the payee, generally via a BOLT 11 invoice.
        ///
        /// Because BOLT 11 route hints can take multiple hops to get to the destination, this may not
        /// terminate at the payee.
-       PrivateHop {
-               /// Information about the private hop communicated via BOLT 11.
-               hint: &'a RouteHintHop,
-               /// Node id of the next hop in BOLT 11 route hint.
-               target_node_id: NodeId
-       },
+       PrivateHop(PrivateHopCandidate<'a>),
        /// A blinded path which starts with an introduction point and ultimately terminates with the
        /// payee.
        ///
@@ -1049,16 +1243,7 @@ pub enum CandidateRouteHop<'a> {
        ///
        /// Because blinded paths are "all or nothing", and we cannot use just one part of a blinded
        /// path, the full path is treated as a single [`CandidateRouteHop`].
-       Blinded {
-               /// Information about the blinded path including the fee, HTLC amount limits, and
-               /// cryptographic material required to build an HTLC through the given path.
-               hint: &'a (BlindedPayInfo, BlindedPath),
-               /// Index of the hint in the original list of blinded hints.
-               ///
-               /// This is used to cheaply uniquely identify this blinded path, even though we don't have
-               /// a short channel ID for this hop.
-               hint_idx: usize,
-       },
+       Blinded(BlindedPathCandidate<'a>),
        /// Similar to [`Self::Blinded`], but the path here only has one hop.
        ///
        /// While we treat this similarly to [`CandidateRouteHop::Blinded`] in many respects (e.g.
@@ -1070,18 +1255,7 @@ pub enum CandidateRouteHop<'a> {
        ///
        /// This primarily exists to track that we need to included a blinded path at the end of our
        /// [`Route`], even though it doesn't actually add an additional hop in the payment.
-       OneHopBlinded {
-               /// Information about the blinded path including the fee, HTLC amount limits, and
-               /// cryptographic material required to build an HTLC terminating with the given path.
-               ///
-               /// Note that the [`BlindedPayInfo`] is ignored here.
-               hint: &'a (BlindedPayInfo, BlindedPath),
-               /// Index of the hint in the original list of blinded hints.
-               ///
-               /// This is used to cheaply uniquely identify this blinded path, even though we don't have
-               /// a short channel ID for this hop.
-               hint_idx: usize,
-       },
+       OneHopBlinded(OneHopBlindedPathCandidate<'a>),
 }
 
 impl<'a> CandidateRouteHop<'a> {
@@ -1103,11 +1277,11 @@ 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,
                }
        }
 
@@ -1119,22 +1293,22 @@ 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(),
                }
        }
 
@@ -1146,11 +1320,11 @@ 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,
                }
        }
 
@@ -1158,10 +1332,10 @@ impl<'a> CandidateRouteHop<'a> {
        #[inline]
        pub fn htlc_minimum_msat(&self) -> u64 {
                match self {
-                       CandidateRouteHop::FirstHop { details, .. } => details.next_outbound_htlc_minimum_msat,
-                       CandidateRouteHop::PublicHop { info, .. } => info.direction().htlc_minimum_msat,
-                       CandidateRouteHop::PrivateHop { hint, .. } => hint.htlc_minimum_msat.unwrap_or(0),
-                       CandidateRouteHop::Blinded { hint, .. } => hint.0.htlc_minimum_msat,
+                       CandidateRouteHop::FirstHop(hop) => hop.details.next_outbound_htlc_minimum_msat,
+                       CandidateRouteHop::PublicHop(hop) => hop.info.direction().htlc_minimum_msat,
+                       CandidateRouteHop::PrivateHop(hop) => hop.hint.htlc_minimum_msat.unwrap_or(0),
+                       CandidateRouteHop::Blinded(hop) => hop.hint.0.htlc_minimum_msat,
                        CandidateRouteHop::OneHopBlinded { .. } => 0,
                }
        }
@@ -1170,35 +1344,39 @@ impl<'a> CandidateRouteHop<'a> {
        #[inline]
        pub fn fees(&self) -> RoutingFees {
                match self {
-                       CandidateRouteHop::FirstHop { .. } => RoutingFees {
+                       CandidateRouteHop::FirstHop(_) => RoutingFees {
                                base_msat: 0, proportional_millionths: 0,
                        },
-                       CandidateRouteHop::PublicHop { info, .. } => info.direction().fees,
-                       CandidateRouteHop::PrivateHop { hint, .. } => hint.fees,
-                       CandidateRouteHop::Blinded { hint, .. } => {
+                       CandidateRouteHop::PublicHop(hop) => hop.info.direction().fees,
+                       CandidateRouteHop::PrivateHop(hop) => hop.hint.fees,
+                       CandidateRouteHop::Blinded(hop) => {
                                RoutingFees {
-                                       base_msat: hint.0.fee_base_msat,
-                                       proportional_millionths: hint.0.fee_proportional_millionths
+                                       base_msat: hop.hint.0.fee_base_msat,
+                                       proportional_millionths: hop.hint.0.fee_proportional_millionths
                                }
                        },
-                       CandidateRouteHop::OneHopBlinded { .. } =>
+                       CandidateRouteHop::OneHopBlinded(_) =>
                                RoutingFees { base_msat: 0, proportional_millionths: 0 },
                }
        }
 
+       /// Fetch the effective capacity of this hop.
+       ///
+       /// Note that this may be somewhat expensive, so calls to this should be limited and results
+       /// cached!
        fn effective_capacity(&self) -> EffectiveCapacity {
                match self {
-                       CandidateRouteHop::FirstHop { details, .. } => EffectiveCapacity::ExactLiquidity {
-                               liquidity_msat: details.next_outbound_htlc_limit_msat,
+                       CandidateRouteHop::FirstHop(hop) => EffectiveCapacity::ExactLiquidity {
+                               liquidity_msat: hop.details.next_outbound_htlc_limit_msat,
                        },
-                       CandidateRouteHop::PublicHop { info, .. } => info.effective_capacity(),
-                       CandidateRouteHop::PrivateHop { hint: RouteHintHop { htlc_maximum_msat: Some(max), .. }, .. } =>
+                       CandidateRouteHop::PublicHop(hop) => hop.info.effective_capacity(),
+                       CandidateRouteHop::PrivateHop(PrivateHopCandidate { hint: RouteHintHop { htlc_maximum_msat: Some(max), .. }, .. }) =>
                                EffectiveCapacity::HintMaxHTLC { amount_msat: *max },
-                       CandidateRouteHop::PrivateHop { hint: RouteHintHop { htlc_maximum_msat: None, .. }, .. } =>
+                       CandidateRouteHop::PrivateHop(PrivateHopCandidate { hint: RouteHintHop { htlc_maximum_msat: None, .. }, .. }) =>
                                EffectiveCapacity::Infinite,
-                       CandidateRouteHop::Blinded { hint, .. } =>
-                               EffectiveCapacity::HintMaxHTLC { amount_msat: hint.0.htlc_maximum_msat },
-                       CandidateRouteHop::OneHopBlinded { .. } => EffectiveCapacity::Infinite,
+                       CandidateRouteHop::Blinded(hop) =>
+                               EffectiveCapacity::HintMaxHTLC { amount_msat: hop.hint.0.htlc_maximum_msat },
+                       CandidateRouteHop::OneHopBlinded(_) => EffectiveCapacity::Infinite,
                }
        }
 
@@ -1208,19 +1386,28 @@ impl<'a> CandidateRouteHop<'a> {
        #[inline]
        fn id(&self) -> CandidateHopId {
                match self {
-                       CandidateRouteHop::Blinded { hint_idx, .. } => CandidateHopId::Blinded(*hint_idx),
-                       CandidateRouteHop::OneHopBlinded { hint_idx, .. } => CandidateHopId::Blinded(*hint_idx),
+                       CandidateRouteHop::Blinded(hop) => CandidateHopId::Blinded(hop.hint_idx),
+                       CandidateRouteHop::OneHopBlinded(hop) => CandidateHopId::Blinded(hop.hint_idx),
                        _ => CandidateHopId::Clear((self.short_channel_id().unwrap(), self.source() < self.target().unwrap())),
                }
        }
        fn blinded_path(&self) -> Option<&'a BlindedPath> {
                match self {
-                       CandidateRouteHop::Blinded { hint, .. } | CandidateRouteHop::OneHopBlinded { hint, .. } => {
+                       CandidateRouteHop::Blinded(BlindedPathCandidate { hint, .. }) | CandidateRouteHop::OneHopBlinded(OneHopBlindedPathCandidate { hint, .. }) => {
                                Some(&hint.1)
                        },
                        _ => None,
                }
        }
+       fn blinded_hint_idx(&self) -> Option<usize> {
+               match self {
+                       Self::Blinded(BlindedPathCandidate { hint_idx, .. }) |
+                       Self::OneHopBlinded(OneHopBlindedPathCandidate { hint_idx, .. }) => {
+                               Some(*hint_idx)
+                       },
+                       _ => None,
+               }
+       }
        /// Returns the source node id of current hop.
        ///
        /// Source node id refers to the node forwarding the HTLC through this hop.
@@ -1229,11 +1416,11 @@ 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.source_node_id,
+                       CandidateRouteHop::OneHopBlinded(hop) => *hop.source_node_id,
                }
        }
        /// Returns the target node id of this hop, if known.
@@ -1248,11 +1435,11 @@ 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,
                }
        }
 }
@@ -1307,15 +1494,15 @@ fn iter_equal<I1: Iterator, I2: Iterator>(mut iter_a: I1, mut iter_b: I2)
 /// 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.
 struct PathBuildingHop<'a> {
        candidate: CandidateRouteHop<'a>,
-       fee_msat: u64,
-
-       /// All the fees paid *after* this channel on the way to the destination
-       next_hops_fee_msat: u64,
-       /// Fee paid for the use of the current channel (see candidate.fees()).
-       /// The value will be actually deducted from the counterparty balance on the previous link.
-       hop_use_fee_msat: u64,
+       /// 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,
        /// 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.
@@ -1327,12 +1514,20 @@ struct PathBuildingHop<'a> {
        /// All penalties incurred from this channel on the way to the destination, as calculated using
        /// channel scoring.
        path_penalty_msat: u64,
-       /// 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,
+
+       // 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
+       next_hops_fee_msat: u64,
+       /// Fee paid for the use of the current channel (see candidate.fees()).
+       /// The value will be actually deducted from the counterparty balance on the previous link.
+       hop_use_fee_msat: u64,
+
        #[cfg(all(not(ldk_bench), any(test, fuzzing)))]
        // In tests, we apply further sanity checks on cases where we skip nodes we already processed
        // to ensure it is specifically in cases where the fee has gone down because of a decrease in
@@ -1341,6 +1536,18 @@ 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;
+
 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");
@@ -1527,17 +1734,29 @@ 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, .. } => {
-                               "blinded route hint with introduction node id ".fmt(f)?;
-                               hint.1.introduction_node_id.fmt(f)?;
+                       CandidateRouteHop::Blinded(BlindedPathCandidate { hint, .. }) | CandidateRouteHop::OneHopBlinded(OneHopBlindedPathCandidate { hint, .. }) => {
+                               "blinded route hint with introduction node ".fmt(f)?;
+                               match &hint.1.introduction_node {
+                                       IntroductionNode::NodeId(pubkey) => write!(f, "id {}", pubkey)?,
+                                       IntroductionNode::DirectedShortChannelId(direction, scid) => {
+                                               match direction {
+                                                       Direction::NodeOne => {
+                                                               write!(f, "one on channel with SCID {}", scid)?;
+                                                       },
+                                                       Direction::NodeTwo => {
+                                                               write!(f, "two on channel with SCID {}", scid)?;
+                                                       },
+                                               }
+                                       }
+                               }
                                " 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)
                        },
@@ -1655,6 +1874,9 @@ where L::Target: Logger {
                return Err(LightningError{err: "Cannot send a payment of 0 msat".to_owned(), action: ErrorAction::IgnoreError});
        }
 
+       let introduction_node_id_cache = payment_params.payee.blinded_route_hints().iter()
+               .map(|(_, path)| path.public_introduction_node_id(network_graph))
+               .collect::<Vec<_>>();
        match &payment_params.payee {
                Payee::Clear { route_hints, node_id, .. } => {
                        for route in route_hints.iter() {
@@ -1666,17 +1888,19 @@ where L::Target: Logger {
                        }
                },
                Payee::Blinded { route_hints, .. } => {
-                       if route_hints.iter().all(|(_, path)| &path.introduction_node_id == our_node_pubkey) {
+                       if introduction_node_id_cache.iter().all(|introduction_node_id| *introduction_node_id == Some(&our_node_id)) {
                                return Err(LightningError{err: "Cannot generate a route to blinded paths if we are the introduction node to all of them".to_owned(), action: ErrorAction::IgnoreError});
                        }
-                       for (_, blinded_path) in route_hints.iter() {
+                       for ((_, blinded_path), introduction_node_id) in route_hints.iter().zip(introduction_node_id_cache.iter()) {
                                if blinded_path.blinded_hops.len() == 0 {
                                        return Err(LightningError{err: "0-hop blinded path provided".to_owned(), action: ErrorAction::IgnoreError});
-                               } else if &blinded_path.introduction_node_id == our_node_pubkey {
+                               } else if *introduction_node_id == Some(&our_node_id) {
                                        log_info!(logger, "Got blinded path with ourselves as the introduction node, ignoring");
                                } else if blinded_path.blinded_hops.len() == 1 &&
-                                       route_hints.iter().any( |(_, p)| p.blinded_hops.len() == 1
-                                               && p.introduction_node_id != blinded_path.introduction_node_id)
+                                       route_hints
+                                               .iter().zip(introduction_node_id_cache.iter())
+                                               .filter(|((_, p), _)| p.blinded_hops.len() == 1)
+                                               .any(|(_, p_introduction_node_id)| p_introduction_node_id != introduction_node_id)
                                {
                                        return Err(LightningError{err: format!("1-hop blinded paths must all have matching introduction node ids"), action: ErrorAction::IgnoreError});
                                }
@@ -1776,7 +2000,7 @@ where L::Target: Logger {
        // inserting first hops suggested by the caller as targets.
        // Our search will then attempt to reach them while traversing from the payee node.
        let mut first_hop_targets: HashMap<_, Vec<&ChannelDetails>> =
-               HashMap::with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 });
+               hash_map_with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 });
        if let Some(hops) = first_hops {
                for chan in hops {
                        if chan.get_outbound_payment_scid().is_none() {
@@ -1795,6 +2019,20 @@ where L::Target: Logger {
                }
        }
 
+       let mut private_hop_key_cache = hash_map_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.
@@ -1802,7 +2040,7 @@ where L::Target: Logger {
 
        // Map from node_id to information about the best current path to that node, including feerate
        // information.
-       let mut dist: HashMap<NodeId, PathBuildingHop> = HashMap::with_capacity(network_nodes.len());
+       let mut dist: HashMap<NodeId, PathBuildingHop> = hash_map_with_capacity(network_nodes.len());
 
        // During routing, if we ignore a path due to an htlc_minimum_msat limit, we set this,
        // indicating that we may wish to try again with a higher value, potentially paying to meet an
@@ -1843,7 +2081,7 @@ where L::Target: Logger {
        // is used. Hence, liquidity used in one direction will not offset any used in the opposite
        // direction.
        let mut used_liquidities: HashMap<CandidateHopId, u64> =
-               HashMap::with_capacity(network_nodes.len());
+               hash_map_with_capacity(network_nodes.len());
 
        // Keeping track of how much value we already collected across other paths. Helps to decide
        // when we want to stop looking for new paths.
@@ -1938,14 +2176,21 @@ where L::Target: Logger {
                                                 (amount_to_transfer_over_msat < $next_hops_path_htlc_minimum_msat &&
                                                  recommended_value_msat >= $next_hops_path_htlc_minimum_msat));
 
-                                       let payment_failed_on_this_channel = scid_opt.map_or(false,
-                                               |scid| payment_params.previously_failed_channels.contains(&scid));
+                                       let payment_failed_on_this_channel = match scid_opt {
+                                               Some(scid) => payment_params.previously_failed_channels.contains(&scid),
+                                               None => match $candidate.blinded_hint_idx() {
+                                                       Some(idx) => {
+                                                               payment_params.previously_failed_blinded_path_idxs.contains(&(idx as u64))
+                                                       },
+                                                       None => false,
+                                               },
+                                       };
 
                                        let (should_log_candidate, first_hop_details) = match $candidate {
-                                               CandidateRouteHop::FirstHop { details, .. } => (true, Some(details)),
-                                               CandidateRouteHop::PrivateHop { .. } => (true, None),
-                                               CandidateRouteHop::Blinded { .. } => (true, None),
-                                               CandidateRouteHop::OneHopBlinded { .. } => (true, None),
+                                               CandidateRouteHop::FirstHop(hop) => (true, Some(hop.details)),
+                                               CandidateRouteHop::PrivateHop(_) => (true, None),
+                                               CandidateRouteHop::Blinded(_) => (true, None),
+                                               CandidateRouteHop::OneHopBlinded(_) => (true, None),
                                                _ => (false, None),
                                        };
 
@@ -2082,15 +2327,6 @@ where L::Target: Logger {
                                                                                score_params);
                                                                let path_penalty_msat = $next_hops_path_penalty_msat
                                                                        .saturating_add(channel_penalty_msat);
-                                                               let new_graph_node = RouteGraphNode {
-                                                                       node_id: src_node_id,
-                                                                       lowest_fee_to_node: total_fee_msat,
-                                                                       total_cltv_delta: hop_total_cltv_delta,
-                                                                       value_contribution_msat,
-                                                                       path_htlc_minimum_msat,
-                                                                       path_penalty_msat,
-                                                                       path_length_to_node,
-                                                               };
 
                                                                // Update the way of reaching $candidate.source()
                                                                // with the given short_channel_id (from $candidate.target()),
@@ -2115,6 +2351,13 @@ where L::Target: Logger {
                                                                        .saturating_add(path_penalty_msat);
 
                                                                if !old_entry.was_processed && new_cost < old_cost {
+                                                                       let new_graph_node = RouteGraphNode {
+                                                                               node_id: src_node_id,
+                                                                               score: cmp::max(total_fee_msat, path_htlc_minimum_msat).saturating_add(path_penalty_msat),
+                                                                               total_cltv_delta: hop_total_cltv_delta,
+                                                                               value_contribution_msat,
+                                                                               path_length_to_node,
+                                                                       };
                                                                        targets.push(new_graph_node);
                                                                        old_entry.next_hops_fee_msat = $next_hops_fee_msat;
                                                                        old_entry.hop_use_fee_msat = hop_use_fee_msat;
@@ -2188,30 +2431,38 @@ where L::Target: Logger {
        // meaning how much will be paid in fees after this node (to the best of our knowledge).
        // This data can later be helpful to optimize routing (pay lower fees).
        macro_rules! add_entries_to_cheapest_to_target_node {
-               ( $node: expr, $node_id: expr, $fee_to_target_msat: expr, $next_hops_value_contribution: expr,
-                 $next_hops_path_htlc_minimum_msat: expr, $next_hops_path_penalty_msat: expr,
+               ( $node: expr, $node_id: expr, $next_hops_value_contribution: expr,
                  $next_hops_cltv_delta: expr, $next_hops_path_length: expr ) => {
+                       let fee_to_target_msat;
+                       let next_hops_path_htlc_minimum_msat;
+                       let next_hops_path_penalty_msat;
                        let skip_node = if let Some(elem) = dist.get_mut(&$node_id) {
                                let 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;
                                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;
                                false
                        };
 
                        if !skip_node {
                                if let Some(first_channels) = first_hop_targets.get(&$node_id) {
                                        for details in first_channels {
-                                               let candidate = CandidateRouteHop::FirstHop {
+                                               let candidate = CandidateRouteHop::FirstHop(FirstHopCandidate {
                                                        details, payer_node_id: &our_node_id,
-                                               };
-                                               add_entry!(&candidate, $fee_to_target_msat,
+                                               });
+                                               add_entry!(&candidate, fee_to_target_msat,
                                                        $next_hops_value_contribution,
-                                                       $next_hops_path_htlc_minimum_msat, $next_hops_path_penalty_msat,
+                                                       next_hops_path_htlc_minimum_msat, next_hops_path_penalty_msat,
                                                        $next_hops_cltv_delta, $next_hops_path_length);
                                        }
                                }
@@ -2229,15 +2480,15 @@ where L::Target: Logger {
                                                        if let Some((directed_channel, source)) = chan.as_directed_to(&$node_id) {
                                                                if first_hops.is_none() || *source != our_node_id {
                                                                        if directed_channel.direction().enabled {
-                                                                               let candidate = CandidateRouteHop::PublicHop {
+                                                                               let candidate = CandidateRouteHop::PublicHop(PublicHopCandidate {
                                                                                        info: directed_channel,
                                                                                        short_channel_id: *chan_id,
-                                                                               };
+                                                                               });
                                                                                add_entry!(&candidate,
-                                                                                       $fee_to_target_msat,
+                                                                                       fee_to_target_msat,
                                                                                        $next_hops_value_contribution,
-                                                                                       $next_hops_path_htlc_minimum_msat,
-                                                                                       $next_hops_path_penalty_msat,
+                                                                                       next_hops_path_htlc_minimum_msat,
+                                                                                       next_hops_path_penalty_msat,
                                                                                        $next_hops_cltv_delta, $next_hops_path_length);
                                                                        }
                                                                }
@@ -2263,9 +2514,9 @@ where L::Target: Logger {
                // place where it could be added.
                payee_node_id_opt.map(|payee| first_hop_targets.get(&payee).map(|first_channels| {
                        for details in first_channels {
-                               let candidate = CandidateRouteHop::FirstHop {
+                               let candidate = CandidateRouteHop::FirstHop(FirstHopCandidate {
                                        details, payer_node_id: &our_node_id,
-                               };
+                               });
                                let added = add_entry!(&candidate, 0, path_value_msat,
                                                                        0, 0u64, 0, 0).is_some();
                                log_trace!(logger, "{} direct route to payee via {}",
@@ -2282,7 +2533,7 @@ where L::Target: Logger {
                        // If not, targets.pop() will not even let us enter the loop in step 2.
                        None => {},
                        Some(node) => {
-                               add_entries_to_cheapest_to_target_node!(node, payee, 0, path_value_msat, 0, 0u64, 0, 0);
+                               add_entries_to_cheapest_to_target_node!(node, payee, path_value_msat, 0, 0);
                        },
                });
 
@@ -2291,30 +2542,57 @@ where L::Target: Logger {
                // earlier than general path finding, they will be somewhat prioritized, although currently
                // 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 =
-                               // 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 }
+                       // 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.
+                       let source_node_id = match introduction_node_id_cache[hint_idx] {
+                               Some(node_id) => node_id,
+                               None => match &hint.1.introduction_node {
+                                       IntroductionNode::NodeId(pubkey) => {
+                                               let node_id = NodeId::from_pubkey(&pubkey);
+                                               match first_hop_targets.get_key_value(&node_id).map(|(key, _)| key) {
+                                                       Some(node_id) => node_id,
+                                                       None => continue,
+                                               }
+                                       },
+                                       IntroductionNode::DirectedShortChannelId(direction, scid) => {
+                                               let first_hop = first_hop_targets.iter().find(|(_, channels)|
+                                                       channels
+                                                               .iter()
+                                                               .any(|details| Some(*scid) == details.get_outbound_payment_scid())
+                                               );
+                                               match first_hop {
+                                                       Some((counterparty_node_id, _)) => {
+                                                               direction.select_node_id(&our_node_id, counterparty_node_id)
+                                                       },
+                                                       None => continue,
+                                               }
+                                       },
+                               },
+                       };
+                       if our_node_id == *source_node_id { continue }
                        let candidate = if hint.1.blinded_hops.len() == 1 {
-                               CandidateRouteHop::OneHopBlinded { hint, hint_idx }
-                       } else { CandidateRouteHop::Blinded { hint, hint_idx } };
+                               CandidateRouteHop::OneHopBlinded(
+                                       OneHopBlindedPathCandidate { source_node_id, hint, hint_idx }
+                               )
+                       } else {
+                               CandidateRouteHop::Blinded(BlindedPathCandidate { source_node_id, hint, hint_idx })
+                       };
                        let mut path_contribution_msat = path_value_msat;
                        if let Some(hop_used_msat) = add_entry!(&candidate,
                                0, path_contribution_msat, 0, 0_u64, 0, 0)
                        {
                                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)) {
-                               sort_first_hop_channels(first_channels, &used_liquidities, recommended_value_msat,
-                                       our_node_pubkey);
+                       if let Some(first_channels) = first_hop_targets.get(source_node_id) {
+                               let mut first_channels = first_channels.clone();
+                               sort_first_hop_channels(
+                                       &mut first_channels, &used_liquidities, recommended_value_msat, our_node_pubkey
+                               );
                                for details in first_channels {
-                                       let first_hop_candidate = CandidateRouteHop::FirstHop {
+                                       let first_hop_candidate = CandidateRouteHop::FirstHop(FirstHopCandidate {
                                                details, payer_node_id: &our_node_id,
-                                       };
+                                       });
                                        let blinded_path_fee = match compute_fees(path_contribution_msat, candidate.fees()) {
                                                Some(fee) => fee,
                                                None => continue
@@ -2353,10 +2631,9 @@ where L::Target: Logger {
                                let mut aggregate_path_contribution_msat = path_value_msat;
 
                                for (idx, (hop, prev_hop_id)) in hop_iter.zip(prev_hop_iter).enumerate() {
-                                       let source = NodeId::from_pubkey(&hop.src_node_id);
-                                       let target = NodeId::from_pubkey(&prev_hop_id);
+                                       let target = private_hop_key_cache.get(prev_hop_id).unwrap();
 
-                                       if let Some(first_channels) = first_hop_targets.get(&target) {
+                                       if let Some(first_channels) = first_hop_targets.get(target) {
                                                if first_channels.iter().any(|d| d.outbound_scid_alias == Some(hop.short_channel_id)) {
                                                        log_trace!(logger, "Ignoring route hint with SCID {} (and any previous) due to it being a direct channel of ours.",
                                                                hop.short_channel_id);
@@ -2366,12 +2643,12 @@ where L::Target: Logger {
 
                                        let candidate = network_channels
                                                .get(&hop.short_channel_id)
-                                               .and_then(|channel| channel.as_directed_to(&target))
-                                               .map(|(info, _)| CandidateRouteHop::PublicHop {
+                                               .and_then(|channel| channel.as_directed_to(target))
+                                               .map(|(info, _)| CandidateRouteHop::PublicHop(PublicHopCandidate {
                                                        info,
                                                        short_channel_id: hop.short_channel_id,
-                                               })
-                                               .unwrap_or_else(|| CandidateRouteHop::PrivateHop { hint: hop, target_node_id: target });
+                                               }))
+                                               .unwrap_or_else(|| CandidateRouteHop::PrivateHop(PrivateHopCandidate { hint: hop, target_node_id: target }));
 
                                        if let Some(hop_used_msat) = add_entry!(&candidate,
                                                aggregate_next_hops_fee_msat, aggregate_path_contribution_msat,
@@ -2407,13 +2684,15 @@ 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) {
-                                               sort_first_hop_channels(first_channels, &used_liquidities,
-                                                       recommended_value_msat, our_node_pubkey);
+                                       if let Some(first_channels) = first_hop_targets.get(target) {
+                                               let mut first_channels = first_channels.clone();
+                                               sort_first_hop_channels(
+                                                       &mut first_channels, &used_liquidities, recommended_value_msat, our_node_pubkey
+                                               );
                                                for details in first_channels {
-                                                       let first_hop_candidate = CandidateRouteHop::FirstHop {
+                                                       let first_hop_candidate = CandidateRouteHop::FirstHop(FirstHopCandidate {
                                                                details, payer_node_id: &our_node_id,
-                                                       };
+                                                       });
                                                        add_entry!(&first_hop_candidate,
                                                                aggregate_next_hops_fee_msat, aggregate_path_contribution_msat,
                                                                aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat,
@@ -2454,13 +2733,15 @@ 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)) {
-                                                       sort_first_hop_channels(first_channels, &used_liquidities,
-                                                               recommended_value_msat, our_node_pubkey);
+                                               if let Some(first_channels) = first_hop_targets.get(&NodeId::from_pubkey(&hop.src_node_id)) {
+                                                       let mut first_channels = first_channels.clone();
+                                                       sort_first_hop_channels(
+                                                               &mut first_channels, &used_liquidities, recommended_value_msat, our_node_pubkey
+                                                       );
                                                        for details in first_channels {
-                                                               let first_hop_candidate = CandidateRouteHop::FirstHop {
+                                                               let first_hop_candidate = CandidateRouteHop::FirstHop(FirstHopCandidate {
                                                                        details, payer_node_id: &our_node_id,
-                                                               };
+                                                               });
                                                                add_entry!(&first_hop_candidate,
                                                                        aggregate_next_hops_fee_msat,
                                                                        aggregate_path_contribution_msat,
@@ -2490,7 +2771,7 @@ where L::Target: Logger {
                // Both these cases (and other cases except reaching recommended_value_msat) mean that
                // paths_collection will be stopped because found_new_path==false.
                // This is not necessarily a routing failure.
-               'path_construction: while let Some(RouteGraphNode { node_id, lowest_fee_to_node, total_cltv_delta, mut value_contribution_msat, path_htlc_minimum_msat, path_penalty_msat, path_length_to_node, .. }) = targets.pop() {
+               'path_construction: while let Some(RouteGraphNode { node_id, total_cltv_delta, mut value_contribution_msat, path_length_to_node, .. }) = targets.pop() {
 
                        // 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.
@@ -2503,7 +2784,7 @@ where L::Target: Logger {
                                        let target = ordered_hops.last().unwrap().0.candidate.target().unwrap_or(maybe_dummy_payee_node_id);
                                        if let Some(first_channels) = first_hop_targets.get(&target) {
                                                for details in first_channels {
-                                                       if let CandidateRouteHop::FirstHop { details: last_hop_details, .. }
+                                                       if let CandidateRouteHop::FirstHop(FirstHopCandidate { details: last_hop_details, .. })
                                                                = ordered_hops.last().unwrap().0.candidate
                                                        {
                                                                if details.get_outbound_payment_scid() == last_hop_details.get_outbound_payment_scid() {
@@ -2528,7 +2809,7 @@ where L::Target: Logger {
                                                }
                                        }
 
-                                       // Means we succesfully traversed from the payer to the payee, now
+                                       // Means we successfully traversed from the payer to the payee, now
                                        // save this path for the payment route. Also, update the liquidity
                                        // remaining on the used hops, so that we take them into account
                                        // while looking for more paths.
@@ -2625,8 +2906,8 @@ where L::Target: Logger {
                        match network_nodes.get(&node_id) {
                                None => {},
                                Some(node) => {
-                                       add_entries_to_cheapest_to_target_node!(node, node_id, lowest_fee_to_node,
-                                               value_contribution_msat, path_htlc_minimum_msat, path_penalty_msat,
+                                       add_entries_to_cheapest_to_target_node!(node, node_id,
+                                               value_contribution_msat,
                                                total_cltv_delta, path_length_to_node);
                                },
                        }
@@ -2770,12 +3051,12 @@ 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
@@ -3000,12 +3281,12 @@ fn build_route_from_hops_internal<L: Deref>(
 
 #[cfg(test)]
 mod tests {
-       use crate::blinded_path::{BlindedHop, BlindedPath};
+       use crate::blinded_path::{BlindedHop, BlindedPath, IntroductionNode};
        use crate::routing::gossip::{NetworkGraph, P2PGossipSync, NodeId, EffectiveCapacity};
        use crate::routing::utxo::UtxoResult;
        use crate::routing::router::{get_route, build_route_from_hops_internal, add_random_cltv_offset, default_node_features,
                BlindedTail, InFlightHtlcs, Path, PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees,
-               DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, MAX_PATH_LENGTH_ESTIMATE, RouteParameters, CandidateRouteHop};
+               DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, MAX_PATH_LENGTH_ESTIMATE, RouteParameters, CandidateRouteHop, PublicHopCandidate};
        use crate::routing::scoring::{ChannelUsage, FixedPenaltyScorer, ScoreLookUp, ProbabilisticScorer, ProbabilisticScoringFeeParameters, ProbabilisticScoringDecayParameters};
        use crate::routing::test_utils::{add_channel, add_or_update_node, build_graph, build_line_graph, id_to_feature_flags, get_nodes, update_channel};
        use crate::chain::transaction::OutPoint;
@@ -3017,7 +3298,7 @@ mod tests {
        use crate::offers::invoice::BlindedPayInfo;
        use crate::util::config::UserConfig;
        use crate::util::test_utils as ln_test_utils;
-       use crate::util::chacha20::ChaCha20;
+       use crate::crypto::chacha20::ChaCha20;
        use crate::util::ser::{Readable, Writeable};
        #[cfg(c_bindings)]
        use crate::util::ser::Writer;
@@ -3036,8 +3317,6 @@ mod tests {
        use crate::prelude::*;
        use crate::sync::Arc;
 
-       use core::convert::TryInto;
-
        fn get_channel_details(short_channel_id: Option<u64>, node_id: PublicKey,
                        features: InitFeatures, outbound_capacity_msat: u64) -> channelmanager::ChannelDetails {
                channelmanager::ChannelDetails {
@@ -3073,6 +3352,8 @@ mod tests {
                        config: None,
                        feerate_sat_per_1000_weight: None,
                        channel_shutdown_state: Some(channelmanager::ChannelShutdownState::NotShuttingDown),
+                       pending_inbound_htlcs: Vec::new(),
+                       pending_outbound_htlcs: Vec::new(),
                }
        }
 
@@ -4867,7 +5148,7 @@ mod tests {
                // MPP to a 1-hop blinded path for nodes[2]
                let bolt12_features = channelmanager::provided_bolt12_invoice_features(&config);
                let blinded_path = BlindedPath {
-                       introduction_node_id: nodes[2],
+                       introduction_node: IntroductionNode::NodeId(nodes[2]),
                        blinding_point: ln_test_utils::pubkey(42),
                        blinded_hops: vec![BlindedHop { blinded_node_id: ln_test_utils::pubkey(42 as u8), encrypted_payload: Vec::new() }],
                };
@@ -4885,18 +5166,18 @@ mod tests {
 
                // MPP to 3 2-hop blinded paths
                let mut blinded_path_node_0 = blinded_path.clone();
-               blinded_path_node_0.introduction_node_id = nodes[0];
+               blinded_path_node_0.introduction_node = IntroductionNode::NodeId(nodes[0]);
                blinded_path_node_0.blinded_hops.push(blinded_path.blinded_hops[0].clone());
                let mut node_0_payinfo = blinded_payinfo.clone();
                node_0_payinfo.htlc_maximum_msat = 50_000;
 
                let mut blinded_path_node_7 = blinded_path_node_0.clone();
-               blinded_path_node_7.introduction_node_id = nodes[7];
+               blinded_path_node_7.introduction_node = IntroductionNode::NodeId(nodes[7]);
                let mut node_7_payinfo = blinded_payinfo.clone();
                node_7_payinfo.htlc_maximum_msat = 60_000;
 
                let mut blinded_path_node_1 = blinded_path_node_0.clone();
-               blinded_path_node_1.introduction_node_id = nodes[1];
+               blinded_path_node_1.introduction_node = IntroductionNode::NodeId(nodes[1]);
                let mut node_1_payinfo = blinded_payinfo.clone();
                node_1_payinfo.htlc_maximum_msat = 180_000;
 
@@ -5078,10 +5359,15 @@ mod tests {
                                if let Some(bt) = &path.blinded_tail {
                                        assert_eq!(path.hops.len() + if bt.hops.len() == 1 { 0 } else { 1 }, 2);
                                        if bt.hops.len() > 1 {
-                                               assert_eq!(path.hops.last().unwrap().pubkey,
+                                               let network_graph = network_graph.read_only();
+                                               assert_eq!(
+                                                       NodeId::from_pubkey(&path.hops.last().unwrap().pubkey),
                                                        payment_params.payee.blinded_route_hints().iter()
                                                                .find(|(p, _)| p.htlc_maximum_msat == path.final_value_msat())
-                                                               .map(|(_, p)| p.introduction_node_id).unwrap());
+                                                               .and_then(|(_, p)| p.public_introduction_node_id(&network_graph))
+                                                               .copied()
+                                                               .unwrap()
+                                               );
                                        } else {
                                                assert_eq!(path.hops.last().unwrap().pubkey, nodes[2]);
                                        }
@@ -6724,7 +7010,7 @@ mod tests {
                        (route.paths[1].hops[1].short_channel_id == 4 && route.paths[0].hops[1].short_channel_id == 13));
        }
 
-       #[cfg(not(feature = "no-std"))]
+       #[cfg(feature = "std")]
        pub(super) fn random_init_seed() -> u64 {
                // Because the default HashMap in std pulls OS randomness, we can use it as a (bad) RNG.
                use core::hash::{BuildHasher, Hasher};
@@ -6734,7 +7020,7 @@ mod tests {
        }
 
        #[test]
-       #[cfg(not(feature = "no-std"))]
+       #[cfg(feature = "std")]
        fn generate_routes() {
                use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
 
@@ -6755,7 +7041,7 @@ mod tests {
        }
 
        #[test]
-       #[cfg(not(feature = "no-std"))]
+       #[cfg(feature = "std")]
        fn generate_routes_mpp() {
                use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
 
@@ -6776,7 +7062,7 @@ mod tests {
        }
 
        #[test]
-       #[cfg(not(feature = "no-std"))]
+       #[cfg(feature = "std")]
        fn generate_large_mpp_routes() {
                use crate::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters};
 
@@ -6819,10 +7105,10 @@ mod tests {
                let channels = network_graph.channels();
                let channel = channels.get(&5).unwrap();
                let info = channel.as_directed_from(&NodeId::from_pubkey(&nodes[3])).unwrap();
-               let candidate: CandidateRouteHop = CandidateRouteHop::PublicHop {
+               let candidate: CandidateRouteHop = CandidateRouteHop::PublicHop(PublicHopCandidate {
                        info: info.0,
                        short_channel_id: 5,
-               };
+               });
                assert_eq!(scorer.channel_penalty_msat(&candidate, usage, &scorer_params), 456);
 
                // Then check we can get a normal route
@@ -6977,7 +7263,7 @@ mod tests {
 
                // Make sure this works for blinded route hints.
                let blinded_path = BlindedPath {
-                       introduction_node_id: intermed_node_id,
+                       introduction_node: IntroductionNode::NodeId(intermed_node_id),
                        blinding_point: ln_test_utils::pubkey(42),
                        blinded_hops: vec![
                                BlindedHop { blinded_node_id: ln_test_utils::pubkey(42), encrypted_payload: vec![] },
@@ -7011,7 +7297,7 @@ mod tests {
        #[test]
        fn blinded_route_ser() {
                let blinded_path_1 = BlindedPath {
-                       introduction_node_id: ln_test_utils::pubkey(42),
+                       introduction_node: IntroductionNode::NodeId(ln_test_utils::pubkey(42)),
                        blinding_point: ln_test_utils::pubkey(43),
                        blinded_hops: vec![
                                BlindedHop { blinded_node_id: ln_test_utils::pubkey(44), encrypted_payload: Vec::new() },
@@ -7019,7 +7305,7 @@ mod tests {
                        ],
                };
                let blinded_path_2 = BlindedPath {
-                       introduction_node_id: ln_test_utils::pubkey(46),
+                       introduction_node: IntroductionNode::NodeId(ln_test_utils::pubkey(46)),
                        blinding_point: ln_test_utils::pubkey(47),
                        blinded_hops: vec![
                                BlindedHop { blinded_node_id: ln_test_utils::pubkey(48), encrypted_payload: Vec::new() },
@@ -7078,7 +7364,7 @@ mod tests {
                // account for the blinded tail's final amount_msat.
                let mut inflight_htlcs = InFlightHtlcs::new();
                let blinded_path = BlindedPath {
-                       introduction_node_id: ln_test_utils::pubkey(43),
+                       introduction_node: IntroductionNode::NodeId(ln_test_utils::pubkey(43)),
                        blinding_point: ln_test_utils::pubkey(48),
                        blinded_hops: vec![BlindedHop { blinded_node_id: ln_test_utils::pubkey(49), encrypted_payload: Vec::new() }],
                };
@@ -7093,7 +7379,7 @@ mod tests {
                                maybe_announced_channel: false,
                        },
                        RouteHop {
-                               pubkey: blinded_path.introduction_node_id,
+                               pubkey: ln_test_utils::pubkey(43),
                                node_features: NodeFeatures::empty(),
                                short_channel_id: 43,
                                channel_features: ChannelFeatures::empty(),
@@ -7117,7 +7403,7 @@ mod tests {
        fn blinded_path_cltv_shadow_offset() {
                // Make sure we add a shadow offset when sending to blinded paths.
                let blinded_path = BlindedPath {
-                       introduction_node_id: ln_test_utils::pubkey(43),
+                       introduction_node: IntroductionNode::NodeId(ln_test_utils::pubkey(43)),
                        blinding_point: ln_test_utils::pubkey(44),
                        blinded_hops: vec![
                                BlindedHop { blinded_node_id: ln_test_utils::pubkey(45), encrypted_payload: Vec::new() },
@@ -7135,7 +7421,7 @@ mod tests {
                                maybe_announced_channel: false,
                        },
                        RouteHop {
-                               pubkey: blinded_path.introduction_node_id,
+                               pubkey: ln_test_utils::pubkey(43),
                                node_features: NodeFeatures::empty(),
                                short_channel_id: 43,
                                channel_features: ChannelFeatures::empty(),
@@ -7177,7 +7463,7 @@ mod tests {
                let random_seed_bytes = keys_manager.get_secure_random_bytes();
 
                let mut blinded_path = BlindedPath {
-                       introduction_node_id: nodes[2],
+                       introduction_node: IntroductionNode::NodeId(nodes[2]),
                        blinding_point: ln_test_utils::pubkey(42),
                        blinded_hops: Vec::with_capacity(num_blinded_hops),
                };
@@ -7209,7 +7495,10 @@ mod tests {
                assert_eq!(tail.final_value_msat, 1001);
 
                let final_hop = route.paths[0].hops.last().unwrap();
-               assert_eq!(final_hop.pubkey, blinded_path.introduction_node_id);
+               assert_eq!(
+                       NodeId::from_pubkey(&final_hop.pubkey),
+                       *blinded_path.public_introduction_node_id(&network_graph).unwrap()
+               );
                if tail.hops.len() > 1 {
                        assert_eq!(final_hop.fee_msat,
                                blinded_payinfo.fee_base_msat as u64 + blinded_payinfo.fee_proportional_millionths as u64 * tail.final_value_msat / 1000000);
@@ -7232,7 +7521,7 @@ mod tests {
                let random_seed_bytes = keys_manager.get_secure_random_bytes();
 
                let mut invalid_blinded_path = BlindedPath {
-                       introduction_node_id: nodes[2],
+                       introduction_node: IntroductionNode::NodeId(nodes[2]),
                        blinding_point: ln_test_utils::pubkey(42),
                        blinded_hops: vec![
                                BlindedHop { blinded_node_id: ln_test_utils::pubkey(43), encrypted_payload: vec![0; 43] },
@@ -7248,7 +7537,7 @@ mod tests {
                };
 
                let mut invalid_blinded_path_2 = invalid_blinded_path.clone();
-               invalid_blinded_path_2.introduction_node_id = ln_test_utils::pubkey(45);
+               invalid_blinded_path_2.introduction_node = IntroductionNode::NodeId(ln_test_utils::pubkey(45));
                let payment_params = PaymentParameters::blinded(vec![
                        (blinded_payinfo.clone(), invalid_blinded_path.clone()),
                        (blinded_payinfo.clone(), invalid_blinded_path_2)]);
@@ -7262,7 +7551,7 @@ mod tests {
                        _ => panic!("Expected error")
                }
 
-               invalid_blinded_path.introduction_node_id = our_id;
+               invalid_blinded_path.introduction_node = IntroductionNode::NodeId(our_id);
                let payment_params = PaymentParameters::blinded(vec![(blinded_payinfo.clone(), invalid_blinded_path.clone())]);
                let route_params = RouteParameters::from_payment_params_and_value(payment_params, 1001);
                match get_route(&our_id, &route_params, &network_graph, None, Arc::clone(&logger), &scorer,
@@ -7274,7 +7563,7 @@ mod tests {
                        _ => panic!("Expected error")
                }
 
-               invalid_blinded_path.introduction_node_id = ln_test_utils::pubkey(46);
+               invalid_blinded_path.introduction_node = IntroductionNode::NodeId(ln_test_utils::pubkey(46));
                invalid_blinded_path.blinded_hops.clear();
                let payment_params = PaymentParameters::blinded(vec![(blinded_payinfo, invalid_blinded_path)]);
                let route_params = RouteParameters::from_payment_params_and_value(payment_params, 1001);
@@ -7303,7 +7592,7 @@ mod tests {
 
                let bolt12_features = channelmanager::provided_bolt12_invoice_features(&config);
                let blinded_path_1 = BlindedPath {
-                       introduction_node_id: nodes[2],
+                       introduction_node: IntroductionNode::NodeId(nodes[2]),
                        blinding_point: ln_test_utils::pubkey(42),
                        blinded_hops: vec![
                                BlindedHop { blinded_node_id: ln_test_utils::pubkey(42 as u8), encrypted_payload: Vec::new() },
@@ -7400,7 +7689,7 @@ mod tests {
                        get_channel_details(Some(1), nodes[1], InitFeatures::from_le_bytes(vec![0b11]), 10_000_000)];
 
                let blinded_path = BlindedPath {
-                       introduction_node_id: nodes[1],
+                       introduction_node: IntroductionNode::NodeId(nodes[1]),
                        blinding_point: ln_test_utils::pubkey(42),
                        blinded_hops: vec![
                                BlindedHop { blinded_node_id: ln_test_utils::pubkey(42 as u8), encrypted_payload: Vec::new() },
@@ -7469,7 +7758,7 @@ mod tests {
                                18446744073709551615)];
 
                let blinded_path = BlindedPath {
-                       introduction_node_id: nodes[1],
+                       introduction_node: IntroductionNode::NodeId(nodes[1]),
                        blinding_point: ln_test_utils::pubkey(42),
                        blinded_hops: vec![
                                BlindedHop { blinded_node_id: ln_test_utils::pubkey(42 as u8), encrypted_payload: Vec::new() },
@@ -7525,7 +7814,7 @@ mod tests {
                let amt_msat = 21_7020_5185_1423_0019;
 
                let blinded_path = BlindedPath {
-                       introduction_node_id: our_id,
+                       introduction_node: IntroductionNode::NodeId(our_id),
                        blinding_point: ln_test_utils::pubkey(42),
                        blinded_hops: vec![
                                BlindedHop { blinded_node_id: ln_test_utils::pubkey(42 as u8), encrypted_payload: Vec::new() },
@@ -7544,7 +7833,7 @@ mod tests {
                        (blinded_payinfo.clone(), blinded_path.clone()),
                        (blinded_payinfo.clone(), blinded_path.clone()),
                ];
-               blinded_hints[1].1.introduction_node_id = nodes[6];
+               blinded_hints[1].1.introduction_node = IntroductionNode::NodeId(nodes[6]);
 
                let bolt12_features = channelmanager::provided_bolt12_invoice_features(&config);
                let payment_params = PaymentParameters::blinded(blinded_hints.clone())
@@ -7577,7 +7866,7 @@ mod tests {
                let amt_msat = 21_7020_5185_1423_0019;
 
                let blinded_path = BlindedPath {
-                       introduction_node_id: our_id,
+                       introduction_node: IntroductionNode::NodeId(our_id),
                        blinding_point: ln_test_utils::pubkey(42),
                        blinded_hops: vec![
                                BlindedHop { blinded_node_id: ln_test_utils::pubkey(42 as u8), encrypted_payload: Vec::new() },
@@ -7601,7 +7890,7 @@ mod tests {
                blinded_hints[1].0.htlc_minimum_msat = 21_7020_5185_1423_0019;
                blinded_hints[1].0.htlc_maximum_msat = 1844_6744_0737_0955_1615;
 
-               blinded_hints[2].1.introduction_node_id = nodes[6];
+               blinded_hints[2].1.introduction_node = IntroductionNode::NodeId(nodes[6]);
 
                let bolt12_features = channelmanager::provided_bolt12_invoice_features(&config);
                let payment_params = PaymentParameters::blinded(blinded_hints.clone())
@@ -7625,7 +7914,7 @@ mod tests {
        fn do_min_htlc_overpay_violates_max_htlc(blinded_payee: bool) {
                // Test that if overpaying to meet a later hop's min_htlc and causes us to violate an earlier
                // hop's max_htlc, we don't consider that candidate hop valid. Previously we would add this hop
-               // to `targets` and build an invalid path with it, and subsquently hit a debug panic asserting
+               // to `targets` and build an invalid path with it, and subsequently hit a debug panic asserting
                // that the used liquidity for a hop was less than its available liquidity limit.
                let secp_ctx = Secp256k1::new();
                let logger = Arc::new(ln_test_utils::TestLogger::new());
@@ -7648,7 +7937,7 @@ mod tests {
                let htlc_min = 2_5165_8240;
                let payment_params = if blinded_payee {
                        let blinded_path = BlindedPath {
-                               introduction_node_id: nodes[0],
+                               introduction_node: IntroductionNode::NodeId(nodes[0]),
                                blinding_point: ln_test_utils::pubkey(42),
                                blinded_hops: vec![
                                        BlindedHop { blinded_node_id: ln_test_utils::pubkey(42 as u8), encrypted_payload: Vec::new() },
@@ -7728,7 +8017,7 @@ mod tests {
                let htlc_mins = [1_4392, 19_7401, 1027, 6_5535];
                let payment_params = if blinded_payee {
                        let blinded_path = BlindedPath {
-                               introduction_node_id: nodes[0],
+                               introduction_node: IntroductionNode::NodeId(nodes[0]),
                                blinding_point: ln_test_utils::pubkey(42),
                                blinded_hops: vec![
                                        BlindedHop { blinded_node_id: ln_test_utils::pubkey(42 as u8), encrypted_payload: Vec::new() },
@@ -7829,7 +8118,7 @@ mod tests {
                                cltv_expiry_delta: 10,
                                features: BlindedHopFeatures::empty(),
                        }, BlindedPath {
-                               introduction_node_id: nodes[0],
+                               introduction_node: IntroductionNode::NodeId(nodes[0]),
                                blinding_point: ln_test_utils::pubkey(42),
                                blinded_hops: vec![
                                        BlindedHop { blinded_node_id: ln_test_utils::pubkey(42 as u8), encrypted_payload: Vec::new() },
@@ -7879,7 +8168,7 @@ mod tests {
                let htlc_mins = [49_0000, 1125_0000];
                let payment_params = {
                        let blinded_path = BlindedPath {
-                               introduction_node_id: nodes[0],
+                               introduction_node: IntroductionNode::NodeId(nodes[0]),
                                blinding_point: ln_test_utils::pubkey(42),
                                blinded_hops: vec![
                                        BlindedHop { blinded_node_id: ln_test_utils::pubkey(42 as u8), encrypted_payload: Vec::new() },
@@ -8112,23 +8401,21 @@ mod tests {
        }
 }
 
-#[cfg(all(any(test, ldk_bench), not(feature = "no-std")))]
+#[cfg(all(any(test, ldk_bench), feature = "std"))]
 pub(crate) mod bench_utils {
        use super::*;
        use std::fs::File;
+       use std::time::Duration;
 
        use bitcoin::hashes::Hash;
-       use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
+       use bitcoin::secp256k1::SecretKey;
 
        use crate::chain::transaction::OutPoint;
        use crate::routing::scoring::ScoreUpdate;
-       use crate::sign::{EntropySource, KeysManager};
+       use crate::sign::KeysManager;
        use crate::ln::ChannelId;
-       use crate::ln::channelmanager::{self, ChannelCounterparty, ChannelDetails};
-       use crate::ln::features::Bolt11InvoiceFeatures;
-       use crate::routing::gossip::NetworkGraph;
+       use crate::ln::channelmanager::{self, ChannelCounterparty};
        use crate::util::config::UserConfig;
-       use crate::util::ser::ReadableArgs;
        use crate::util::test_utils::TestLogger;
 
        /// Tries to open a network graph file, or panics with a URL to fetch it.
@@ -8213,6 +8500,8 @@ pub(crate) mod bench_utils {
                        config: None,
                        feerate_sat_per_1000_weight: None,
                        channel_shutdown_state: Some(channelmanager::ChannelShutdownState::NotShuttingDown),
+                       pending_inbound_htlcs: Vec::new(),
+                       pending_outbound_htlcs: Vec::new(),
                }
        }
 
@@ -8264,16 +8553,16 @@ pub(crate) mod bench_utils {
                                                if let Ok(route) = route_res {
                                                        for path in route.paths {
                                                                if seed & 0x80 == 0 {
-                                                                       scorer.payment_path_successful(&path);
+                                                                       scorer.payment_path_successful(&path, Duration::ZERO);
                                                                } else {
                                                                        let short_channel_id = path.hops[path.hops.len() / 2].short_channel_id;
-                                                                       scorer.payment_path_failed(&path, short_channel_id);
+                                                                       scorer.payment_path_failed(&path, short_channel_id, Duration::ZERO);
                                                                }
                                                                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.
+                                               // If we couldn't find a path with a higher amount, reduce and try again.
                                                score_amt /= 100;
                                        }