Concretize `WriteableScore` into `MultiThreadedLockableScore`
[rust-lightning] / lightning / src / routing / scoring.rs
index 2c62e6465041254e815bcbf9f372189e10830fb3..9fb7bee9a75c5a23796971b603d4f226cd07d19a 100644 (file)
@@ -17,9 +17,9 @@
 //! ```
 //! # extern crate bitcoin;
 //! #
-//! # use lightning::routing::network_graph::NetworkGraph;
+//! # use lightning::routing::gossip::NetworkGraph;
 //! # use lightning::routing::router::{RouteParameters, find_route};
-//! # use lightning::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringParameters, Scorer, ScoringParameters};
+//! # use lightning::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringParameters};
 //! # use lightning::chain::keysinterface::{KeysManager, KeysInterface};
 //! # use lightning::util::logger::{Logger, Record};
 //! # use bitcoin::secp256k1::PublicKey;
@@ -28,7 +28,7 @@
 //! # impl Logger for FakeLogger {
 //! #     fn log(&self, record: &Record) { unimplemented!() }
 //! # }
-//! # fn find_scored_route(payer: PublicKey, route_params: RouteParameters, network_graph: NetworkGraph) {
+//! # fn find_scored_route(payer: PublicKey, route_params: RouteParameters, network_graph: NetworkGraph<&FakeLogger>) {
 //! # let logger = FakeLogger {};
 //! #
 //! // Use the default channel penalties.
@@ -55,7 +55,7 @@
 //! [`find_route`]: crate::routing::router::find_route
 
 use ln::msgs::DecodeError;
-use routing::network_graph::{EffectiveCapacity, NetworkGraph, NodeId};
+use routing::gossip::{EffectiveCapacity, NetworkGraph, NodeId};
 use routing::router::RouteHop;
 use util::ser::{Readable, ReadableArgs, Writeable, Writer};
 use util::logger::Logger;
@@ -63,7 +63,9 @@ use util::time::Time;
 
 use prelude::*;
 use core::fmt;
-use core::cell::{RefCell, RefMut};
+#[cfg(not(c_bindings))]
+use core::cell::RefCell;
+use core::cell::RefMut;
 use core::ops::{Deref, DerefMut};
 use core::time::Duration;
 use io::{self, Read};
@@ -102,6 +104,12 @@ pub trait Score $(: $supertrait)* {
 
        /// Handles updating channel penalties after successfully routing along a path.
        fn payment_path_successful(&mut self, path: &[&RouteHop]);
+
+       /// Handles updating channel penalties after a probe over the given path failed.
+       fn probe_failed(&mut self, path: &[&RouteHop], short_channel_id: u64);
+
+       /// Handles updating channel penalties after a probe over the given path succeeded.
+       fn probe_successful(&mut self, path: &[&RouteHop]);
 }
 
 impl<S: Score, T: DerefMut<Target=S> $(+ $supertrait)*> Score for T {
@@ -118,6 +126,14 @@ impl<S: Score, T: DerefMut<Target=S> $(+ $supertrait)*> Score for T {
        fn payment_path_successful(&mut self, path: &[&RouteHop]) {
                self.deref_mut().payment_path_successful(path)
        }
+
+       fn probe_failed(&mut self, path: &[&RouteHop], short_channel_id: u64) {
+               self.deref_mut().probe_failed(path, short_channel_id)
+       }
+
+       fn probe_successful(&mut self, path: &[&RouteHop]) {
+               self.deref_mut().probe_successful(path)
+       }
 }
 } }
 
@@ -146,11 +162,13 @@ pub trait LockableScore<'a> {
 ///
 /// We need this trait to be able to pass in a scorer to `lightning-background-processor` that will enable us to
 /// use the Persister to persist it.
+#[cfg(not(c_bindings))] // This doesn't make sense in bindings as all `Score`s are `Writeable`.
 pub trait WriteableScore<'a>: LockableScore<'a> + Writeable {}
 
+#[cfg(not(c_bindings))] // This doesn't make sense in bindings as all `Score`s are `Writeable`.
 impl<'a, T> WriteableScore<'a> for T where T: LockableScore<'a> + Writeable {}
 
-/// (C-not exported)
+#[cfg(not(c_bindings))]
 impl<'a, T: 'a + Score> LockableScore<'a> for Mutex<T> {
        type Locked = MutexGuard<'a, T>;
 
@@ -159,6 +177,7 @@ impl<'a, T: 'a + Score> LockableScore<'a> for Mutex<T> {
        }
 }
 
+#[cfg(not(c_bindings))]
 impl<'a, T: 'a + Score> LockableScore<'a> for RefCell<T> {
        type Locked = RefMut<'a, T>;
 
@@ -174,14 +193,21 @@ pub struct MultiThreadedLockableScore<S: Score> {
 }
 #[cfg(c_bindings)]
 /// (C-not exported)
-impl<'a, T: Score + 'a> LockableScore<'a> for MultiThreadedLockableScore<T> {
-       type Locked = MutexGuard<'a, T>;
+impl<'a, S: Score + 'a> LockableScore<'a> for MultiThreadedLockableScore<S> {
+       type Locked = MutexGuard<'a, S>;
 
-       fn lock(&'a self) -> MutexGuard<'a, T> {
+       fn lock(&'a self) -> MutexGuard<'a, S> {
                Mutex::lock(&self.score).unwrap()
        }
 }
 
+#[cfg(c_bindings)]
+impl<S: Score> Writeable for MultiThreadedLockableScore<S> {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
+               S::write(&*self.lock(), writer)
+       }
+}
+
 #[cfg(c_bindings)]
 impl<T: Score> MultiThreadedLockableScore<T> {
        /// Creates a new [`MultiThreadedLockableScore`] given an underlying [`Score`].
@@ -241,6 +267,10 @@ impl Score for FixedPenaltyScorer {
        fn payment_path_failed(&mut self, _path: &[&RouteHop], _short_channel_id: u64) {}
 
        fn payment_path_successful(&mut self, _path: &[&RouteHop]) {}
+
+       fn probe_failed(&mut self, _path: &[&RouteHop], _short_channel_id: u64) {}
+
+       fn probe_successful(&mut self, _path: &[&RouteHop]) {}
 }
 
 impl Writeable for FixedPenaltyScorer {
@@ -259,262 +289,31 @@ impl ReadableArgs<u64> for FixedPenaltyScorer {
        }
 }
 
-/// [`Score`] implementation that provides reasonable default behavior.
+#[cfg(not(feature = "no-std"))]
+/// [`Score`] implementation using channel success probability distributions.
+///
+/// Based on *Optimally Reliable & Cheap Payment Flows on the Lightning Network* by Rene Pickhardt
+/// and Stefan Richter [[1]]. Given the uncertainty of channel liquidity balances, probability
+/// distributions are defined based on knowledge learned from successful and unsuccessful attempts.
+/// Then the negative `log10` of the success probability is used to determine the cost of routing a
+/// specific HTLC amount through a channel.
 ///
-/// Used to apply a fixed penalty to each channel, thus avoiding long paths when shorter paths with
-/// slightly higher fees are available. Will further penalize channels that fail to relay payments.
+/// Knowledge about channel liquidity balances takes the form of upper and lower bounds on the
+/// possible liquidity. Certainty of the bounds is decreased over time using a decay function. See
+/// [`ProbabilisticScoringParameters`] for details.
 ///
-/// See [module-level documentation] for usage and [`ScoringParameters`] for customization.
+/// Since the scorer aims to learn the current channel liquidity balances, it works best for nodes
+/// with high payment volume or that actively probe the [`NetworkGraph`]. Nodes with low payment
+/// volume are more likely to experience failed payment paths, which would need to be retried.
 ///
 /// # Note
 ///
 /// Mixing the `no-std` feature between serialization and deserialization results in undefined
 /// behavior.
 ///
-/// [module-level documentation]: crate::routing::scoring
-#[deprecated(
-       since = "0.0.105",
-       note = "ProbabilisticScorer should be used instead of Scorer.",
-)]
-pub type Scorer = ScorerUsingTime::<ConfiguredTime>;
-
-#[cfg(not(feature = "no-std"))]
-type ConfiguredTime = std::time::Instant;
-#[cfg(feature = "no-std")]
-use util::time::Eternity;
+/// [1]: https://arxiv.org/abs/2107.05322
+pub type ProbabilisticScorer<G, L> = ProbabilisticScorerUsingTime::<G, L, std::time::Instant>;
 #[cfg(feature = "no-std")]
-type ConfiguredTime = Eternity;
-
-// Note that ideally we'd hide ScorerUsingTime from public view by sealing it as well, but rustdoc
-// doesn't handle this well - instead exposing a `Scorer` which has no trait implementation(s) or
-// methods at all.
-
-/// [`Score`] implementation.
-///
-/// (C-not exported) generally all users should use the [`Scorer`] type alias.
-pub struct ScorerUsingTime<T: Time> {
-       params: ScoringParameters,
-       // TODO: Remove entries of closed channels.
-       channel_failures: HashMap<u64, ChannelFailure<T>>,
-}
-
-#[derive(Clone)]
-/// Parameters for configuring [`Scorer`].
-pub struct ScoringParameters {
-       /// A fixed penalty in msats to apply to each channel.
-       ///
-       /// Default value: 500 msat
-       pub base_penalty_msat: u64,
-
-       /// A penalty in msats to apply to a channel upon failing to relay a payment.
-       ///
-       /// This accumulates for each failure but may be reduced over time based on
-       /// [`failure_penalty_half_life`] or when successfully routing through a channel.
-       ///
-       /// Default value: 1,024,000 msat
-       ///
-       /// [`failure_penalty_half_life`]: Self::failure_penalty_half_life
-       pub failure_penalty_msat: u64,
-
-       /// When the amount being sent over a channel is this many 1024ths of the total channel
-       /// capacity, we begin applying [`overuse_penalty_msat_per_1024th`].
-       ///
-       /// Default value: 128 1024ths (i.e. begin penalizing when an HTLC uses 1/8th of a channel)
-       ///
-       /// [`overuse_penalty_msat_per_1024th`]: Self::overuse_penalty_msat_per_1024th
-       pub overuse_penalty_start_1024th: u16,
-
-       /// A penalty applied, per whole 1024ths of the channel capacity which the amount being sent
-       /// over the channel exceeds [`overuse_penalty_start_1024th`] by.
-       ///
-       /// Default value: 20 msat (i.e. 2560 msat penalty to use 1/4th of a channel, 7680 msat penalty
-       ///                to use half a channel, and 12,560 msat penalty to use 3/4ths of a channel)
-       ///
-       /// [`overuse_penalty_start_1024th`]: Self::overuse_penalty_start_1024th
-       pub overuse_penalty_msat_per_1024th: u64,
-
-       /// The time required to elapse before any accumulated [`failure_penalty_msat`] penalties are
-       /// cut in half.
-       ///
-       /// Successfully routing through a channel will immediately cut the penalty in half as well.
-       ///
-       /// Default value: 1 hour
-       ///
-       /// # Note
-       ///
-       /// When built with the `no-std` feature, time will never elapse. Therefore, this penalty will
-       /// never decay.
-       ///
-       /// [`failure_penalty_msat`]: Self::failure_penalty_msat
-       pub failure_penalty_half_life: Duration,
-}
-
-impl_writeable_tlv_based!(ScoringParameters, {
-       (0, base_penalty_msat, required),
-       (1, overuse_penalty_start_1024th, (default_value, 128)),
-       (2, failure_penalty_msat, required),
-       (3, overuse_penalty_msat_per_1024th, (default_value, 20)),
-       (4, failure_penalty_half_life, required),
-});
-
-/// Accounting for penalties against a channel for failing to relay any payments.
-///
-/// Penalties decay over time, though accumulate as more failures occur.
-struct ChannelFailure<T: Time> {
-       /// Accumulated penalty in msats for the channel as of `last_updated`.
-       undecayed_penalty_msat: u64,
-
-       /// Last time the channel either failed to route or successfully routed a payment. Used to decay
-       /// `undecayed_penalty_msat`.
-       last_updated: T,
-}
-
-impl<T: Time> ScorerUsingTime<T> {
-       /// Creates a new scorer using the given scoring parameters.
-       pub fn new(params: ScoringParameters) -> Self {
-               Self {
-                       params,
-                       channel_failures: HashMap::new(),
-               }
-       }
-}
-
-impl<T: Time> ChannelFailure<T> {
-       fn new(failure_penalty_msat: u64) -> Self {
-               Self {
-                       undecayed_penalty_msat: failure_penalty_msat,
-                       last_updated: T::now(),
-               }
-       }
-
-       fn add_penalty(&mut self, failure_penalty_msat: u64, half_life: Duration) {
-               self.undecayed_penalty_msat = self.decayed_penalty_msat(half_life) + failure_penalty_msat;
-               self.last_updated = T::now();
-       }
-
-       fn reduce_penalty(&mut self, half_life: Duration) {
-               self.undecayed_penalty_msat = self.decayed_penalty_msat(half_life) >> 1;
-               self.last_updated = T::now();
-       }
-
-       fn decayed_penalty_msat(&self, half_life: Duration) -> u64 {
-               self.last_updated.elapsed().as_secs()
-                       .checked_div(half_life.as_secs())
-                       .and_then(|decays| self.undecayed_penalty_msat.checked_shr(decays as u32))
-                       .unwrap_or(0)
-       }
-}
-
-impl<T: Time> Default for ScorerUsingTime<T> {
-       fn default() -> Self {
-               Self::new(ScoringParameters::default())
-       }
-}
-
-impl Default for ScoringParameters {
-       fn default() -> Self {
-               Self {
-                       base_penalty_msat: 500,
-                       failure_penalty_msat: 1024 * 1000,
-                       failure_penalty_half_life: Duration::from_secs(3600),
-                       overuse_penalty_start_1024th: 1024 / 8,
-                       overuse_penalty_msat_per_1024th: 20,
-               }
-       }
-}
-
-impl<T: Time> Score for ScorerUsingTime<T> {
-       fn channel_penalty_msat(
-               &self, short_channel_id: u64, _source: &NodeId, _target: &NodeId, usage: ChannelUsage
-       ) -> u64 {
-               let failure_penalty_msat = self.channel_failures
-                       .get(&short_channel_id)
-                       .map_or(0, |value| value.decayed_penalty_msat(self.params.failure_penalty_half_life));
-
-               let mut penalty_msat = self.params.base_penalty_msat + failure_penalty_msat;
-               let send_amt_msat = usage.amount_msat;
-               let capacity_msat = usage.effective_capacity.as_msat()
-                       .saturating_sub(usage.inflight_htlc_msat);
-               let send_1024ths = send_amt_msat.checked_mul(1024).unwrap_or(u64::max_value()) / capacity_msat;
-               if send_1024ths > self.params.overuse_penalty_start_1024th as u64 {
-                       penalty_msat = penalty_msat.checked_add(
-                                       (send_1024ths - self.params.overuse_penalty_start_1024th as u64)
-                                       .checked_mul(self.params.overuse_penalty_msat_per_1024th).unwrap_or(u64::max_value()))
-                               .unwrap_or(u64::max_value());
-               }
-
-               penalty_msat
-       }
-
-       fn payment_path_failed(&mut self, _path: &[&RouteHop], short_channel_id: u64) {
-               let failure_penalty_msat = self.params.failure_penalty_msat;
-               let half_life = self.params.failure_penalty_half_life;
-               self.channel_failures
-                       .entry(short_channel_id)
-                       .and_modify(|failure| failure.add_penalty(failure_penalty_msat, half_life))
-                       .or_insert_with(|| ChannelFailure::new(failure_penalty_msat));
-       }
-
-       fn payment_path_successful(&mut self, path: &[&RouteHop]) {
-               let half_life = self.params.failure_penalty_half_life;
-               for hop in path.iter() {
-                       self.channel_failures
-                               .entry(hop.short_channel_id)
-                               .and_modify(|failure| failure.reduce_penalty(half_life));
-               }
-       }
-}
-
-impl<T: Time> Writeable for ScorerUsingTime<T> {
-       #[inline]
-       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
-               self.params.write(w)?;
-               self.channel_failures.write(w)?;
-               write_tlv_fields!(w, {});
-               Ok(())
-       }
-}
-
-impl<T: Time> Readable for ScorerUsingTime<T> {
-       #[inline]
-       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
-               let res = Ok(Self {
-                       params: Readable::read(r)?,
-                       channel_failures: Readable::read(r)?,
-               });
-               read_tlv_fields!(r, {});
-               res
-       }
-}
-
-impl<T: Time> Writeable for ChannelFailure<T> {
-       #[inline]
-       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
-               let duration_since_epoch = T::duration_since_epoch() - self.last_updated.elapsed();
-               write_tlv_fields!(w, {
-                       (0, self.undecayed_penalty_msat, required),
-                       (2, duration_since_epoch, required),
-               });
-               Ok(())
-       }
-}
-
-impl<T: Time> Readable for ChannelFailure<T> {
-       #[inline]
-       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
-               let mut undecayed_penalty_msat = 0;
-               let mut duration_since_epoch = Duration::from_secs(0);
-               read_tlv_fields!(r, {
-                       (0, undecayed_penalty_msat, required),
-                       (2, duration_since_epoch, required),
-               });
-               Ok(Self {
-                       undecayed_penalty_msat,
-                       last_updated: T::now() - (T::duration_since_epoch() - duration_since_epoch),
-               })
-       }
-}
-
 /// [`Score`] implementation using channel success probability distributions.
 ///
 /// Based on *Optimally Reliable & Cheap Payment Flows on the Lightning Network* by Rene Pickhardt
@@ -537,12 +336,13 @@ impl<T: Time> Readable for ChannelFailure<T> {
 /// behavior.
 ///
 /// [1]: https://arxiv.org/abs/2107.05322
-pub type ProbabilisticScorer<G, L> = ProbabilisticScorerUsingTime::<G, L, ConfiguredTime>;
+pub type ProbabilisticScorer<G, L> = ProbabilisticScorerUsingTime::<G, L, ::util::time::Eternity>;
 
 /// Probabilistic [`Score`] implementation.
 ///
 /// (C-not exported) generally all users should use the [`ProbabilisticScorer`] type alias.
-pub struct ProbabilisticScorerUsingTime<G: Deref<Target = NetworkGraph>, L: Deref, T: Time> where L::Target: Logger {
+pub struct ProbabilisticScorerUsingTime<G: Deref<Target = NetworkGraph<L>>, L: Deref, T: Time>
+where L::Target: Logger {
        params: ProbabilisticScoringParameters,
        network_graph: G,
        logger: L,
@@ -554,13 +354,30 @@ pub struct ProbabilisticScorerUsingTime<G: Deref<Target = NetworkGraph>, L: Dere
 ///
 /// Used to configure base, liquidity, and amount penalties, the sum of which comprises the channel
 /// penalty (i.e., the amount in msats willing to be paid to avoid routing through the channel).
-#[derive(Clone, Copy)]
+///
+/// The penalty applied to any channel by the [`ProbabilisticScorer`] is the sum of each of the
+/// parameters here.
+#[derive(Clone)]
 pub struct ProbabilisticScoringParameters {
        /// A fixed penalty in msats to apply to each channel.
        ///
        /// Default value: 500 msat
        pub base_penalty_msat: u64,
 
+       /// A multiplier used with the payment amount to calculate a fixed penalty applied to each
+       /// channel, in excess of the [`base_penalty_msat`].
+       ///
+       /// The purpose of the amount penalty is to avoid having fees dominate the channel cost (i.e.,
+       /// fees plus penalty) for large payments. The penalty is computed as the product of this
+       /// multiplier and `2^30`ths of the payment amount.
+       ///
+       /// ie `base_penalty_amount_multiplier_msat * amount_msat / 2^30`
+       ///
+       /// Default value: 8,192 msat
+       ///
+       /// [`base_penalty_msat`]: Self::base_penalty_msat
+       pub base_penalty_amount_multiplier_msat: u64,
+
        /// A multiplier used in conjunction with the negative `log10` of the channel's success
        /// probability for a payment to determine the liquidity penalty.
        ///
@@ -599,7 +416,7 @@ pub struct ProbabilisticScoringParameters {
        /// multiplier and `2^20`ths of the payment amount, weighted by the negative `log10` of the
        /// success probability.
        ///
-       /// `-log10(success_probability) * amount_penalty_multiplier_msat * amount_msat / 2^20`
+       /// `-log10(success_probability) * liquidity_penalty_amount_multiplier_msat * amount_msat / 2^20`
        ///
        /// In practice, this means for 0.1 success probability (`-log10(0.1) == 1`) each `2^20`th of
        /// the amount will result in a penalty of the multiplier. And, as the success probability
@@ -608,7 +425,41 @@ pub struct ProbabilisticScoringParameters {
        /// fall below `1`.
        ///
        /// Default value: 256 msat
-       pub amount_penalty_multiplier_msat: u64,
+       pub liquidity_penalty_amount_multiplier_msat: u64,
+
+       /// Manual penalties used for the given nodes. Allows to set a particular penalty for a given
+       /// node. Note that a manual penalty of `u64::max_value()` means the node would not ever be
+       /// considered during path finding.
+       ///
+       /// (C-not exported)
+       pub manual_node_penalties: HashMap<NodeId, u64>,
+
+       /// This penalty is applied when `htlc_maximum_msat` is equal to or larger than half of the
+       /// channel's capacity, which makes us prefer nodes with a smaller `htlc_maximum_msat`. We
+       /// treat such nodes preferentially as this makes balance discovery attacks harder to execute,
+       /// thereby creating an incentive to restrict `htlc_maximum_msat` and improve privacy.
+       ///
+       /// Default value: 250 msat
+       pub anti_probing_penalty_msat: u64,
+
+       /// This penalty is applied when the amount we're attempting to send over a channel exceeds our
+       /// current estimate of the channel's available liquidity.
+       ///
+       /// Note that in this case all other penalties, including the
+       /// [`liquidity_penalty_multiplier_msat`] and [`liquidity_penalty_amount_multiplier_msat`]-based
+       /// penalties, as well as the [`base_penalty_msat`] and the [`anti_probing_penalty_msat`], if
+       /// applicable, are still included in the overall penalty.
+       ///
+       /// If you wish to avoid creating paths with such channels entirely, setting this to a value of
+       /// `u64::max_value()` will guarantee that.
+       ///
+       /// Default value: 1_0000_0000_000 msat (1 Bitcoin)
+       ///
+       /// [`liquidity_penalty_multiplier_msat`]: Self::liquidity_penalty_multiplier_msat
+       /// [`liquidity_penalty_amount_multiplier_msat`]: Self::liquidity_penalty_amount_multiplier_msat
+       /// [`base_penalty_msat`]: Self::base_penalty_msat
+       /// [`anti_probing_penalty_msat`]: Self::anti_probing_penalty_msat
+       pub considered_impossible_penalty_msat: u64,
 }
 
 /// Accounting for channel liquidity balance uncertainty.
@@ -638,7 +489,7 @@ struct DirectedChannelLiquidity<L: Deref<Target = u64>, T: Time, U: Deref<Target
        half_life: Duration,
 }
 
-impl<G: Deref<Target = NetworkGraph>, L: Deref, T: Time> ProbabilisticScorerUsingTime<G, L, T> where L::Target: Logger {
+impl<G: Deref<Target = NetworkGraph<L>>, L: Deref, T: Time> ProbabilisticScorerUsingTime<G, L, T> where L::Target: Logger {
        /// Creates a new scorer using the given scoring parameters for sending payments from a node
        /// through a network graph.
        pub fn new(params: ProbabilisticScoringParameters, network_graph: G, logger: L) -> Self {
@@ -682,6 +533,49 @@ impl<G: Deref<Target = NetworkGraph>, L: Deref, T: Time> ProbabilisticScorerUsin
                        }
                }
        }
+
+       /// Query the estimated minimum and maximum liquidity available for sending a payment over the
+       /// channel with `scid` towards the given `target` node.
+       pub fn estimated_channel_liquidity_range(&self, scid: u64, target: &NodeId) -> Option<(u64, u64)> {
+               let graph = self.network_graph.read_only();
+
+               if let Some(chan) = graph.channels().get(&scid) {
+                       if let Some(liq) = self.channel_liquidities.get(&scid) {
+                               if let Some((directed_info, source)) = chan.as_directed_to(target) {
+                                       let amt = directed_info.effective_capacity().as_msat();
+                                       let dir_liq = liq.as_directed(source, target, amt, self.params.liquidity_offset_half_life);
+                                       return Some((dir_liq.min_liquidity_msat(), dir_liq.max_liquidity_msat()));
+                               }
+                       }
+               }
+               None
+       }
+
+       /// Marks the node with the given `node_id` as banned, i.e.,
+       /// it will be avoided during path finding.
+       pub fn add_banned(&mut self, node_id: &NodeId) {
+               self.params.manual_node_penalties.insert(*node_id, u64::max_value());
+       }
+
+       /// Removes the node with the given `node_id` from the list of nodes to avoid.
+       pub fn remove_banned(&mut self, node_id: &NodeId) {
+               self.params.manual_node_penalties.remove(node_id);
+       }
+
+       /// Sets a manual penalty for the given node.
+       pub fn set_manual_penalty(&mut self, node_id: &NodeId, penalty: u64) {
+               self.params.manual_node_penalties.insert(*node_id, penalty);
+       }
+
+       /// Removes the node with the given `node_id` from the list of manual penalties.
+       pub fn remove_manual_penalty(&mut self, node_id: &NodeId) {
+               self.params.manual_node_penalties.remove(node_id);
+       }
+
+       /// Clears the list of manual penalties that are applied during path finding.
+       pub fn clear_manual_penalties(&mut self) {
+               self.params.manual_node_penalties = HashMap::new();
+       }
 }
 
 impl ProbabilisticScoringParameters {
@@ -689,9 +583,21 @@ impl ProbabilisticScoringParameters {
        fn zero_penalty() -> Self {
                Self {
                        base_penalty_msat: 0,
+                       base_penalty_amount_multiplier_msat: 0,
                        liquidity_penalty_multiplier_msat: 0,
                        liquidity_offset_half_life: Duration::from_secs(3600),
-                       amount_penalty_multiplier_msat: 0,
+                       liquidity_penalty_amount_multiplier_msat: 0,
+                       manual_node_penalties: HashMap::new(),
+                       anti_probing_penalty_msat: 0,
+                       considered_impossible_penalty_msat: 0,
+               }
+       }
+
+       /// Marks all nodes in the given list as banned, i.e.,
+       /// they will be avoided during path finding.
+       pub fn add_banned_from_list(&mut self, node_ids: Vec<NodeId>) {
+               for id in node_ids {
+                       self.manual_node_penalties.insert(id, u64::max_value());
                }
        }
 }
@@ -700,9 +606,13 @@ impl Default for ProbabilisticScoringParameters {
        fn default() -> Self {
                Self {
                        base_penalty_msat: 500,
+                       base_penalty_amount_multiplier_msat: 8192,
                        liquidity_penalty_multiplier_msat: 40_000,
                        liquidity_offset_half_life: Duration::from_secs(3600),
-                       amount_penalty_multiplier_msat: 256,
+                       liquidity_penalty_amount_multiplier_msat: 256,
+                       manual_node_penalties: HashMap::new(),
+                       anti_probing_penalty_msat: 250,
+                       considered_impossible_penalty_msat: 1_0000_0000_000,
                }
        }
 }
@@ -770,35 +680,31 @@ const PRECISION_LOWER_BOUND_DENOMINATOR: u64 = approx::LOWER_BITS_BOUND;
 
 /// The divisor used when computing the amount penalty.
 const AMOUNT_PENALTY_DIVISOR: u64 = 1 << 20;
+const BASE_AMOUNT_PENALTY_DIVISOR: u64 = 1 << 30;
 
 impl<L: Deref<Target = u64>, T: Time, U: Deref<Target = T>> DirectedChannelLiquidity<L, T, U> {
-       /// Returns a penalty for routing the given HTLC `amount_msat` through the channel in this
-       /// direction.
-       fn penalty_msat(&self, amount_msat: u64, params: ProbabilisticScoringParameters) -> u64 {
+       /// Returns a liquidity penalty for routing the given HTLC `amount_msat` through the channel in
+       /// this direction.
+       fn penalty_msat(&self, amount_msat: u64, params: &ProbabilisticScoringParameters) -> u64 {
                let max_liquidity_msat = self.max_liquidity_msat();
                let min_liquidity_msat = core::cmp::min(self.min_liquidity_msat(), max_liquidity_msat);
                if amount_msat <= min_liquidity_msat {
                        0
                } else if amount_msat >= max_liquidity_msat {
-                       if amount_msat > max_liquidity_msat {
-                               u64::max_value()
-                       } else if max_liquidity_msat != self.capacity_msat {
-                               // Avoid using the failed channel on retry.
-                               u64::max_value()
-                       } else {
-                               // Equivalent to hitting the else clause below with the amount equal to the
-                               // effective capacity and without any certainty on the liquidity upper bound.
-                               let negative_log10_times_2048 = NEGATIVE_LOG10_UPPER_BOUND * 2048;
-                               self.combined_penalty_msat(amount_msat, negative_log10_times_2048, params)
-                       }
+                       // Equivalent to hitting the else clause below with the amount equal to the effective
+                       // capacity and without any certainty on the liquidity upper bound, plus the
+                       // impossibility penalty.
+                       let negative_log10_times_2048 = NEGATIVE_LOG10_UPPER_BOUND * 2048;
+                       self.combined_penalty_msat(amount_msat, negative_log10_times_2048, params)
+                               .saturating_add(params.considered_impossible_penalty_msat)
                } else {
                        let numerator = (max_liquidity_msat - amount_msat).saturating_add(1);
                        let denominator = (max_liquidity_msat - min_liquidity_msat).saturating_add(1);
                        if amount_msat - min_liquidity_msat < denominator / PRECISION_LOWER_BOUND_DENOMINATOR {
                                // If the failure probability is < 1.5625% (as 1 - numerator/denominator < 1/64),
                                // don't bother trying to use the log approximation as it gets too noisy to be
-                               // particularly helpful, instead just round down to 0 and return the base penalty.
-                               params.base_penalty_msat
+                               // particularly helpful, instead just round down to 0.
+                               0
                        } else {
                                let negative_log10_times_2048 =
                                        approx::negative_log10_times_2048(numerator, denominator);
@@ -807,11 +713,11 @@ impl<L: Deref<Target = u64>, T: Time, U: Deref<Target = T>> DirectedChannelLiqui
                }
        }
 
-       /// Computes the liquidity and amount penalties and adds them to the base penalty.
+       /// Computes the liquidity penalty from the penalty multipliers.
        #[inline(always)]
        fn combined_penalty_msat(
                &self, amount_msat: u64, negative_log10_times_2048: u64,
-               params: ProbabilisticScoringParameters
+               params: &ProbabilisticScoringParameters
        ) -> u64 {
                let liquidity_penalty_msat = {
                        // Upper bound the liquidity penalty to ensure some channel is selected.
@@ -820,12 +726,10 @@ impl<L: Deref<Target = u64>, T: Time, U: Deref<Target = T>> DirectedChannelLiqui
                        (negative_log10_times_2048.saturating_mul(multiplier_msat) / 2048).min(max_penalty_msat)
                };
                let amount_penalty_msat = negative_log10_times_2048
-                       .saturating_mul(params.amount_penalty_multiplier_msat)
+                       .saturating_mul(params.liquidity_penalty_amount_multiplier_msat)
                        .saturating_mul(amount_msat) / 2048 / AMOUNT_PENALTY_DIVISOR;
 
-               params.base_penalty_msat
-                       .saturating_add(liquidity_penalty_msat)
-                       .saturating_add(amount_penalty_msat)
+               liquidity_penalty_msat.saturating_add(amount_penalty_msat)
        }
 
        /// Returns the lower bound of the channel liquidity balance in this direction.
@@ -899,10 +803,35 @@ impl<L: DerefMut<Target = u64>, T: Time, U: DerefMut<Target = T>> DirectedChanne
        }
 }
 
-impl<G: Deref<Target = NetworkGraph>, L: Deref, T: Time> Score for ProbabilisticScorerUsingTime<G, L, T> where L::Target: Logger {
+impl<G: Deref<Target = NetworkGraph<L>>, L: Deref, T: Time> Score for ProbabilisticScorerUsingTime<G, L, T> where L::Target: Logger {
        fn channel_penalty_msat(
                &self, short_channel_id: u64, source: &NodeId, target: &NodeId, usage: ChannelUsage
        ) -> u64 {
+               if let Some(penalty) = self.params.manual_node_penalties.get(target) {
+                       return *penalty;
+               }
+
+               let base_penalty_msat = self.params.base_penalty_msat.saturating_add(
+                       self.params.base_penalty_amount_multiplier_msat
+                               .saturating_mul(usage.amount_msat) / BASE_AMOUNT_PENALTY_DIVISOR);
+
+               let mut anti_probing_penalty_msat = 0;
+               match usage.effective_capacity {
+                       EffectiveCapacity::ExactLiquidity { liquidity_msat } => {
+                               if usage.amount_msat > liquidity_msat {
+                                       return u64::max_value();
+                               } else {
+                                       return base_penalty_msat;
+                               }
+                       },
+                       EffectiveCapacity::Total { capacity_msat, htlc_maximum_msat: Some(htlc_maximum_msat) } => {
+                               if htlc_maximum_msat >= capacity_msat/2 {
+                                       anti_probing_penalty_msat = self.params.anti_probing_penalty_msat;
+                               }
+                       },
+                       _ => {},
+               }
+
                let liquidity_offset_half_life = self.params.liquidity_offset_half_life;
                let amount_msat = usage.amount_msat;
                let capacity_msat = usage.effective_capacity.as_msat()
@@ -911,7 +840,9 @@ impl<G: Deref<Target = NetworkGraph>, L: Deref, T: Time> Score for Probabilistic
                        .get(&short_channel_id)
                        .unwrap_or(&ChannelLiquidity::new())
                        .as_directed(source, target, capacity_msat, liquidity_offset_half_life)
-                       .penalty_msat(amount_msat, self.params)
+                       .penalty_msat(amount_msat, &self.params)
+                       .saturating_add(anti_probing_penalty_msat)
+                       .saturating_add(base_penalty_msat)
        }
 
        fn payment_path_failed(&mut self, path: &[&RouteHop], short_channel_id: u64) {
@@ -979,6 +910,14 @@ impl<G: Deref<Target = NetworkGraph>, L: Deref, T: Time> Score for Probabilistic
                        }
                }
        }
+
+       fn probe_failed(&mut self, path: &[&RouteHop], short_channel_id: u64) {
+               self.payment_path_failed(path, short_channel_id)
+       }
+
+       fn probe_successful(&mut self, path: &[&RouteHop]) {
+               self.payment_path_failed(path, u64::max_value())
+       }
 }
 
 mod approx {
@@ -1291,17 +1230,17 @@ mod approx {
        }
 }
 
-impl<G: Deref<Target = NetworkGraph>, L: Deref, T: Time> Writeable for ProbabilisticScorerUsingTime<G, L, T> where L::Target: Logger {
+impl<G: Deref<Target = NetworkGraph<L>>, L: Deref, T: Time> Writeable for ProbabilisticScorerUsingTime<G, L, T> where L::Target: Logger {
        #[inline]
        fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
                write_tlv_fields!(w, {
-                       (0, self.channel_liquidities, required)
+                       (0, self.channel_liquidities, required),
                });
                Ok(())
        }
 }
 
-impl<G: Deref<Target = NetworkGraph>, L: Deref, T: Time>
+impl<G: Deref<Target = NetworkGraph<L>>, L: Deref, T: Time>
 ReadableArgs<(ProbabilisticScoringParameters, G, L)> for ProbabilisticScorerUsingTime<G, L, T> where L::Target: Logger {
        #[inline]
        fn read<R: Read>(
@@ -1310,7 +1249,7 @@ ReadableArgs<(ProbabilisticScoringParameters, G, L)> for ProbabilisticScorerUsin
                let (params, network_graph, logger) = args;
                let mut channel_liquidities = HashMap::new();
                read_tlv_fields!(r, {
-                       (0, channel_liquidities, required)
+                       (0, channel_liquidities, required),
                });
                Ok(Self {
                        params,
@@ -1345,26 +1284,38 @@ impl<T: Time> Readable for ChannelLiquidity<T> {
                        (2, max_liquidity_offset_msat, required),
                        (4, duration_since_epoch, required),
                });
+               // On rust prior to 1.60 `Instant::duration_since` will panic if time goes backwards.
+               // We write `last_updated` as wallclock time even though its ultimately an `Instant` (which
+               // is a time from a monotonic clock usually represented as an offset against boot time).
+               // Thus, we have to construct an `Instant` by subtracting the difference in wallclock time
+               // from the one that was written. However, because `Instant` can panic if we construct one
+               // in the future, we must handle wallclock time jumping backwards, which we do by simply
+               // using `Instant::now()` in that case.
+               let wall_clock_now = T::duration_since_epoch();
+               let now = T::now();
+               let last_updated = if wall_clock_now > duration_since_epoch {
+                       now - (wall_clock_now - duration_since_epoch)
+               } else { now };
                Ok(Self {
                        min_liquidity_offset_msat,
                        max_liquidity_offset_msat,
-                       last_updated: T::now() - (T::duration_since_epoch() - duration_since_epoch),
+                       last_updated,
                })
        }
 }
 
 #[cfg(test)]
 mod tests {
-       use super::{ChannelLiquidity, ProbabilisticScoringParameters, ProbabilisticScorerUsingTime, ScoringParameters, ScorerUsingTime};
+       use super::{ChannelLiquidity, ProbabilisticScoringParameters, ProbabilisticScorerUsingTime};
        use util::time::Time;
        use util::time::tests::SinceEpoch;
 
        use ln::features::{ChannelFeatures, NodeFeatures};
-       use ln::msgs::{ChannelAnnouncement, ChannelUpdate, OptionalField, UnsignedChannelAnnouncement, UnsignedChannelUpdate};
-       use routing::scoring::{ChannelUsage, Score};
-       use routing::network_graph::{EffectiveCapacity, NetworkGraph, NodeId};
+       use ln::msgs::{ChannelAnnouncement, ChannelUpdate, UnsignedChannelAnnouncement, UnsignedChannelUpdate};
+       use routing::gossip::{EffectiveCapacity, NetworkGraph, NodeId};
        use routing::router::RouteHop;
-       use util::ser::{Readable, ReadableArgs, Writeable};
+       use routing::scoring::{ChannelUsage, Score};
+       use util::ser::{ReadableArgs, Writeable};
        use util::test_utils::TestLogger;
 
        use bitcoin::blockdata::constants::genesis_block;
@@ -1375,9 +1326,6 @@ mod tests {
        use core::time::Duration;
        use io;
 
-       /// A scorer for testing with time that can be manually advanced.
-       type Scorer = ScorerUsingTime::<SinceEpoch>;
-
        fn source_privkey() -> SecretKey {
                SecretKey::from_slice(&[42; 32]).unwrap()
        }
@@ -1404,279 +1352,10 @@ mod tests {
                NodeId::from_pubkey(&target_pubkey())
        }
 
-       #[test]
-       fn penalizes_without_channel_failures() {
-               let scorer = Scorer::new(ScoringParameters {
-                       base_penalty_msat: 1_000,
-                       failure_penalty_msat: 512,
-                       failure_penalty_half_life: Duration::from_secs(1),
-                       overuse_penalty_start_1024th: 1024,
-                       overuse_penalty_msat_per_1024th: 0,
-               });
-               let source = source_node_id();
-               let target = target_node_id();
-               let usage = ChannelUsage {
-                       amount_msat: 1, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown
-               };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_000);
-
-               SinceEpoch::advance(Duration::from_secs(1));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_000);
-       }
-
-       #[test]
-       fn accumulates_channel_failure_penalties() {
-               let mut scorer = Scorer::new(ScoringParameters {
-                       base_penalty_msat: 1_000,
-                       failure_penalty_msat: 64,
-                       failure_penalty_half_life: Duration::from_secs(10),
-                       overuse_penalty_start_1024th: 1024,
-                       overuse_penalty_msat_per_1024th: 0,
-               });
-               let source = source_node_id();
-               let target = target_node_id();
-               let usage = ChannelUsage {
-                       amount_msat: 1, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown
-               };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_000);
-
-               scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_064);
-
-               scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_128);
-
-               scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_192);
-       }
-
-       #[test]
-       fn decays_channel_failure_penalties_over_time() {
-               let mut scorer = Scorer::new(ScoringParameters {
-                       base_penalty_msat: 1_000,
-                       failure_penalty_msat: 512,
-                       failure_penalty_half_life: Duration::from_secs(10),
-                       overuse_penalty_start_1024th: 1024,
-                       overuse_penalty_msat_per_1024th: 0,
-               });
-               let source = source_node_id();
-               let target = target_node_id();
-               let usage = ChannelUsage {
-                       amount_msat: 1, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown
-               };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_000);
-
-               scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_512);
-
-               SinceEpoch::advance(Duration::from_secs(9));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_512);
-
-               SinceEpoch::advance(Duration::from_secs(1));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_256);
-
-               SinceEpoch::advance(Duration::from_secs(10 * 8));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_001);
-
-               SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_000);
-
-               SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_000);
-       }
-
-       #[test]
-       fn decays_channel_failure_penalties_without_shift_overflow() {
-               let mut scorer = Scorer::new(ScoringParameters {
-                       base_penalty_msat: 1_000,
-                       failure_penalty_msat: 512,
-                       failure_penalty_half_life: Duration::from_secs(10),
-                       overuse_penalty_start_1024th: 1024,
-                       overuse_penalty_msat_per_1024th: 0,
-               });
-               let source = source_node_id();
-               let target = target_node_id();
-               let usage = ChannelUsage {
-                       amount_msat: 1, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown
-               };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_000);
-
-               scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_512);
-
-               // An unchecked right shift 64 bits or more in ChannelFailure::decayed_penalty_msat would
-               // cause an overflow.
-               SinceEpoch::advance(Duration::from_secs(10 * 64));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_000);
-
-               SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_000);
-       }
-
-       #[test]
-       fn accumulates_channel_failure_penalties_after_decay() {
-               let mut scorer = Scorer::new(ScoringParameters {
-                       base_penalty_msat: 1_000,
-                       failure_penalty_msat: 512,
-                       failure_penalty_half_life: Duration::from_secs(10),
-                       overuse_penalty_start_1024th: 1024,
-                       overuse_penalty_msat_per_1024th: 0,
-               });
-               let source = source_node_id();
-               let target = target_node_id();
-               let usage = ChannelUsage {
-                       amount_msat: 1, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown
-               };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_000);
-
-               scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_512);
-
-               SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_256);
-
-               scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_768);
-
-               SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_384);
-       }
-
-       #[test]
-       fn reduces_channel_failure_penalties_after_success() {
-               let mut scorer = Scorer::new(ScoringParameters {
-                       base_penalty_msat: 1_000,
-                       failure_penalty_msat: 512,
-                       failure_penalty_half_life: Duration::from_secs(10),
-                       overuse_penalty_start_1024th: 1024,
-                       overuse_penalty_msat_per_1024th: 0,
-               });
-               let source = source_node_id();
-               let target = target_node_id();
-               let usage = ChannelUsage {
-                       amount_msat: 1, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown
-               };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_000);
-
-               scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_512);
-
-               SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_256);
-
-               let hop = RouteHop {
-                       pubkey: PublicKey::from_slice(target.as_slice()).unwrap(),
-                       node_features: NodeFeatures::known(),
-                       short_channel_id: 42,
-                       channel_features: ChannelFeatures::known(),
-                       fee_msat: 1,
-                       cltv_expiry_delta: 18,
-               };
-               scorer.payment_path_successful(&[&hop]);
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_128);
-
-               SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_064);
-       }
-
-       #[test]
-       fn restores_persisted_channel_failure_penalties() {
-               let mut scorer = Scorer::new(ScoringParameters {
-                       base_penalty_msat: 1_000,
-                       failure_penalty_msat: 512,
-                       failure_penalty_half_life: Duration::from_secs(10),
-                       overuse_penalty_start_1024th: 1024,
-                       overuse_penalty_msat_per_1024th: 0,
-               });
-               let source = source_node_id();
-               let target = target_node_id();
-               let usage = ChannelUsage {
-                       amount_msat: 1, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown
-               };
-
-               scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_512);
-
-               SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_256);
-
-               scorer.payment_path_failed(&[], 43);
-               assert_eq!(scorer.channel_penalty_msat(43, &source, &target, usage), 1_512);
-
-               let mut serialized_scorer = Vec::new();
-               scorer.write(&mut serialized_scorer).unwrap();
-
-               let deserialized_scorer = <Scorer>::read(&mut io::Cursor::new(&serialized_scorer)).unwrap();
-               assert_eq!(deserialized_scorer.channel_penalty_msat(42, &source, &target, usage), 1_256);
-               assert_eq!(deserialized_scorer.channel_penalty_msat(43, &source, &target, usage), 1_512);
-       }
-
-       #[test]
-       fn decays_persisted_channel_failure_penalties() {
-               let mut scorer = Scorer::new(ScoringParameters {
-                       base_penalty_msat: 1_000,
-                       failure_penalty_msat: 512,
-                       failure_penalty_half_life: Duration::from_secs(10),
-                       overuse_penalty_start_1024th: 1024,
-                       overuse_penalty_msat_per_1024th: 0,
-               });
-               let source = source_node_id();
-               let target = target_node_id();
-               let usage = ChannelUsage {
-                       amount_msat: 1, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown
-               };
-
-               scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1_512);
-
-               let mut serialized_scorer = Vec::new();
-               scorer.write(&mut serialized_scorer).unwrap();
-
-               SinceEpoch::advance(Duration::from_secs(10));
-
-               let deserialized_scorer = <Scorer>::read(&mut io::Cursor::new(&serialized_scorer)).unwrap();
-               assert_eq!(deserialized_scorer.channel_penalty_msat(42, &source, &target, usage), 1_256);
-
-               SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(deserialized_scorer.channel_penalty_msat(42, &source, &target, usage), 1_128);
-       }
-
-       #[test]
-       fn charges_per_1024th_penalty() {
-               let scorer = Scorer::new(ScoringParameters {
-                       base_penalty_msat: 0,
-                       failure_penalty_msat: 0,
-                       failure_penalty_half_life: Duration::from_secs(0),
-                       overuse_penalty_start_1024th: 256,
-                       overuse_penalty_msat_per_1024th: 100,
-               });
-               let source = source_node_id();
-               let target = target_node_id();
-
-               let usage = ChannelUsage {
-                       amount_msat: 1_000,
-                       inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000 },
-               };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 0);
-
-               let usage = ChannelUsage { amount_msat: 256_999, ..usage };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 0);
-
-               let usage = ChannelUsage { amount_msat: 257_000, ..usage };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 100);
-
-               let usage = ChannelUsage { amount_msat: 258_000, ..usage };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 200);
-
-               let usage = ChannelUsage { amount_msat: 512_000, ..usage };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 256 * 100);
-       }
-
        // `ProbabilisticScorer` tests
 
        /// A probabilistic scorer for testing with time that can be manually advanced.
-       type ProbabilisticScorer<'a> = ProbabilisticScorerUsingTime::<&'a NetworkGraph, &'a TestLogger, SinceEpoch>;
+       type ProbabilisticScorer<'a> = ProbabilisticScorerUsingTime::<&'a NetworkGraph<&'a TestLogger>, &'a TestLogger, SinceEpoch>;
 
        fn sender_privkey() -> SecretKey {
                SecretKey::from_slice(&[41; 32]).unwrap()
@@ -1704,9 +1383,9 @@ mod tests {
                NodeId::from_pubkey(&recipient_pubkey())
        }
 
-       fn network_graph() -> NetworkGraph {
+       fn network_graph(logger: &TestLogger) -> NetworkGraph<&TestLogger> {
                let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
-               let mut network_graph = NetworkGraph::new(genesis_hash);
+               let mut network_graph = NetworkGraph::new(genesis_hash, logger);
                add_channel(&mut network_graph, 42, source_privkey(), target_privkey());
                add_channel(&mut network_graph, 43, target_privkey(), recipient_privkey());
 
@@ -1714,7 +1393,7 @@ mod tests {
        }
 
        fn add_channel(
-               network_graph: &mut NetworkGraph, short_channel_id: u64, node_1_key: SecretKey,
+               network_graph: &mut NetworkGraph<&TestLogger>, short_channel_id: u64, node_1_key: SecretKey,
                node_2_key: SecretKey
        ) {
                let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
@@ -1741,13 +1420,14 @@ mod tests {
                };
                let chain_source: Option<&::util::test_utils::TestChainSource> = None;
                network_graph.update_channel_from_announcement(
-                       &signed_announcement, &chain_source, &secp_ctx).unwrap();
+                       &signed_announcement, &chain_source).unwrap();
                update_channel(network_graph, short_channel_id, node_1_key, 0);
                update_channel(network_graph, short_channel_id, node_2_key, 1);
        }
 
        fn update_channel(
-               network_graph: &mut NetworkGraph, short_channel_id: u64, node_key: SecretKey, flags: u8
+               network_graph: &mut NetworkGraph<&TestLogger>, short_channel_id: u64, node_key: SecretKey,
+               flags: u8
        ) {
                let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
                let secp_ctx = Secp256k1::new();
@@ -1758,7 +1438,7 @@ mod tests {
                        flags,
                        cltv_expiry_delta: 18,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(1_000),
+                       htlc_maximum_msat: 1_000,
                        fee_base_msat: 1,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new(),
@@ -1768,7 +1448,7 @@ mod tests {
                        signature: secp_ctx.sign_ecdsa(&msghash, &node_key),
                        contents: unsigned_update,
                };
-               network_graph.update_channel(&signed_update, &secp_ctx).unwrap();
+               network_graph.update_channel(&signed_update).unwrap();
        }
 
        fn payment_path_for_amount(amount_msat: u64) -> Vec<RouteHop> {
@@ -1804,7 +1484,7 @@ mod tests {
        fn liquidity_bounds_directed_from_lowest_node_id() {
                let logger = TestLogger::new();
                let last_updated = SinceEpoch::now();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters::default();
                let mut scorer = ProbabilisticScorer::new(params, &network_graph, &logger)
                        .with_channel(42,
@@ -1879,7 +1559,7 @@ mod tests {
        fn resets_liquidity_upper_bound_when_crossed_by_lower_bound() {
                let logger = TestLogger::new();
                let last_updated = SinceEpoch::now();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters::default();
                let mut scorer = ProbabilisticScorer::new(params, &network_graph, &logger)
                        .with_channel(42,
@@ -1937,7 +1617,7 @@ mod tests {
        fn resets_liquidity_lower_bound_when_crossed_by_upper_bound() {
                let logger = TestLogger::new();
                let last_updated = SinceEpoch::now();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters::default();
                let mut scorer = ProbabilisticScorer::new(params, &network_graph, &logger)
                        .with_channel(42,
@@ -1994,7 +1674,7 @@ mod tests {
        #[test]
        fn increased_penalty_nearing_liquidity_upper_bound() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
                        ..ProbabilisticScoringParameters::zero_penalty()
@@ -2006,20 +1686,20 @@ mod tests {
                let usage = ChannelUsage {
                        amount_msat: 1_024,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: Some(1_000) },
                };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 0);
                let usage = ChannelUsage { amount_msat: 10_240, ..usage };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 0);
                let usage = ChannelUsage { amount_msat: 102_400, ..usage };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 47);
-               let usage = ChannelUsage { amount_msat: 1_024_000, ..usage };
+               let usage = ChannelUsage { amount_msat: 1_023_999, ..usage };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 2_000);
 
                let usage = ChannelUsage {
                        amount_msat: 128,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: Some(1_000) },
                };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 58);
                let usage = ChannelUsage { amount_msat: 256, ..usage };
@@ -2040,9 +1720,10 @@ mod tests {
        fn constant_penalty_outside_liquidity_bounds() {
                let logger = TestLogger::new();
                let last_updated = SinceEpoch::now();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
+                       considered_impossible_penalty_msat: u64::max_value(),
                        ..ProbabilisticScoringParameters::zero_penalty()
                };
                let scorer = ProbabilisticScorer::new(params, &network_graph, &logger)
@@ -2056,7 +1737,7 @@ mod tests {
                let usage = ChannelUsage {
                        amount_msat: 39,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 100 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 100, htlc_maximum_msat: Some(1_000) },
                };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 0);
                let usage = ChannelUsage { amount_msat: 50, ..usage };
@@ -2069,7 +1750,7 @@ mod tests {
        #[test]
        fn does_not_further_penalize_own_channel() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
                        ..ProbabilisticScoringParameters::zero_penalty()
@@ -2080,7 +1761,7 @@ mod tests {
                let usage = ChannelUsage {
                        amount_msat: 500,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: Some(1_000) },
                };
                let failed_path = payment_path_for_amount(500);
                let successful_path = payment_path_for_amount(200);
@@ -2097,7 +1778,7 @@ mod tests {
        #[test]
        fn sets_liquidity_lower_bound_on_downstream_failure() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
                        ..ProbabilisticScoringParameters::zero_penalty()
@@ -2110,7 +1791,7 @@ mod tests {
                let usage = ChannelUsage {
                        amount_msat: 250,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: Some(1_000) },
                };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 128);
                let usage = ChannelUsage { amount_msat: 500, ..usage };
@@ -2131,9 +1812,10 @@ mod tests {
        #[test]
        fn sets_liquidity_upper_bound_on_failure() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
+                       considered_impossible_penalty_msat: u64::max_value(),
                        ..ProbabilisticScoringParameters::zero_penalty()
                };
                let mut scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
@@ -2144,7 +1826,7 @@ mod tests {
                let usage = ChannelUsage {
                        amount_msat: 250,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: Some(1_000) },
                };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 128);
                let usage = ChannelUsage { amount_msat: 500, ..usage };
@@ -2165,7 +1847,7 @@ mod tests {
        #[test]
        fn reduces_liquidity_upper_bound_along_path_on_success() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
                        ..ProbabilisticScoringParameters::zero_penalty()
@@ -2178,7 +1860,7 @@ mod tests {
                let usage = ChannelUsage {
                        amount_msat: 250,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: Some(1_000) },
                };
                let path = payment_path_for_amount(500);
 
@@ -2196,10 +1878,11 @@ mod tests {
        #[test]
        fn decays_liquidity_bounds_over_time() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
                        liquidity_offset_half_life: Duration::from_secs(10),
+                       considered_impossible_penalty_msat: u64::max_value(),
                        ..ProbabilisticScoringParameters::zero_penalty()
                };
                let mut scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
@@ -2209,10 +1892,10 @@ mod tests {
                let usage = ChannelUsage {
                        amount_msat: 0,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: Some(1_024) },
                };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 0);
-               let usage = ChannelUsage { amount_msat: 1_024, ..usage };
+               let usage = ChannelUsage { amount_msat: 1_023, ..usage };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 2_000);
 
                scorer.payment_path_failed(&payment_path_for_amount(768).iter().collect::<Vec<_>>(), 42);
@@ -2256,26 +1939,26 @@ mod tests {
                let usage = ChannelUsage { amount_msat: 1_023, ..usage };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 2_000);
                let usage = ChannelUsage { amount_msat: 1_024, ..usage };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 2_000);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), u64::max_value());
 
                // Fully decay liquidity upper bound.
                SinceEpoch::advance(Duration::from_secs(10));
                let usage = ChannelUsage { amount_msat: 0, ..usage };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 0);
                let usage = ChannelUsage { amount_msat: 1_024, ..usage };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 2_000);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), u64::max_value());
 
                SinceEpoch::advance(Duration::from_secs(10));
                let usage = ChannelUsage { amount_msat: 0, ..usage };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 0);
                let usage = ChannelUsage { amount_msat: 1_024, ..usage };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 2_000);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), u64::max_value());
        }
 
        #[test]
        fn decays_liquidity_bounds_without_shift_overflow() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
                        liquidity_offset_half_life: Duration::from_secs(10),
@@ -2287,7 +1970,7 @@ mod tests {
                let usage = ChannelUsage {
                        amount_msat: 256,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: Some(1_000) },
                };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 125);
 
@@ -2306,7 +1989,7 @@ mod tests {
        #[test]
        fn restricts_liquidity_bounds_after_decay() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
                        liquidity_offset_half_life: Duration::from_secs(10),
@@ -2318,7 +2001,7 @@ mod tests {
                let usage = ChannelUsage {
                        amount_msat: 512,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: Some(1_000) },
                };
 
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 300);
@@ -2350,19 +2033,20 @@ mod tests {
        #[test]
        fn restores_persisted_liquidity_bounds() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
                        liquidity_offset_half_life: Duration::from_secs(10),
+                       considered_impossible_penalty_msat: u64::max_value(),
                        ..ProbabilisticScoringParameters::zero_penalty()
                };
-               let mut scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
+               let mut scorer = ProbabilisticScorer::new(params.clone(), &network_graph, &logger);
                let source = source_node_id();
                let target = target_node_id();
                let usage = ChannelUsage {
                        amount_msat: 500,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: Some(1_000) },
                };
 
                scorer.payment_path_failed(&payment_path_for_amount(500).iter().collect::<Vec<_>>(), 42);
@@ -2386,19 +2070,20 @@ mod tests {
        #[test]
        fn decays_persisted_liquidity_bounds() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
                        liquidity_offset_half_life: Duration::from_secs(10),
+                       considered_impossible_penalty_msat: u64::max_value(),
                        ..ProbabilisticScoringParameters::zero_penalty()
                };
-               let mut scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
+               let mut scorer = ProbabilisticScorer::new(params.clone(), &network_graph, &logger);
                let source = source_node_id();
                let target = target_node_id();
                let usage = ChannelUsage {
                        amount_msat: 500,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: Some(1_000) },
                };
 
                scorer.payment_path_failed(&payment_path_for_amount(500).iter().collect::<Vec<_>>(), 42);
@@ -2426,7 +2111,7 @@ mod tests {
                // Shows the scores of "realistic" sends of 100k sats over channels of 1-10m sats (with a
                // 50k sat reserve).
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let params = ProbabilisticScoringParameters::default();
                let scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
                let source = source_node_id();
@@ -2435,61 +2120,61 @@ mod tests {
                let usage = ChannelUsage {
                        amount_msat: 100_000_000,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 950_000_000 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 950_000_000, htlc_maximum_msat: Some(1_000) },
                };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 3613);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 4375);
                let usage = ChannelUsage {
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_950_000_000 }, ..usage
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_950_000_000, htlc_maximum_msat: Some(1_000) }, ..usage
                };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1977);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 2739);
                let usage = ChannelUsage {
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 2_950_000_000 }, ..usage
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 2_950_000_000, htlc_maximum_msat: Some(1_000) }, ..usage
                };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1474);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 2236);
                let usage = ChannelUsage {
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 3_950_000_000 }, ..usage
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 3_950_000_000, htlc_maximum_msat: Some(1_000) }, ..usage
                };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1223);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1985);
                let usage = ChannelUsage {
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 4_950_000_000 }, ..usage
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 4_950_000_000, htlc_maximum_msat: Some(1_000) }, ..usage
                };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 877);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1639);
                let usage = ChannelUsage {
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 5_950_000_000 }, ..usage
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 5_950_000_000, htlc_maximum_msat: Some(1_000) }, ..usage
                };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 845);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1607);
                let usage = ChannelUsage {
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 6_950_000_000 }, ..usage
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 6_950_000_000, htlc_maximum_msat: Some(1_000) }, ..usage
                };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 500);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1262);
                let usage = ChannelUsage {
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 7_450_000_000 }, ..usage
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 7_450_000_000, htlc_maximum_msat: Some(1_000) }, ..usage
                };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 500);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1262);
                let usage = ChannelUsage {
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 7_950_000_000 }, ..usage
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 7_950_000_000, htlc_maximum_msat: Some(1_000) }, ..usage
                };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 500);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1262);
                let usage = ChannelUsage {
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 8_950_000_000 }, ..usage
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 8_950_000_000, htlc_maximum_msat: Some(1_000) }, ..usage
                };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 500);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1262);
                let usage = ChannelUsage {
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 9_950_000_000 }, ..usage
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 9_950_000_000, htlc_maximum_msat: Some(1_000) }, ..usage
                };
-               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 500);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 1262);
        }
 
        #[test]
        fn adds_base_penalty_to_liquidity_penalty() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let source = source_node_id();
                let target = target_node_id();
                let usage = ChannelUsage {
                        amount_msat: 128,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: Some(1_000) },
                };
 
                let params = ProbabilisticScoringParameters {
@@ -2500,27 +2185,37 @@ mod tests {
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 58);
 
                let params = ProbabilisticScoringParameters {
-                       base_penalty_msat: 500, liquidity_penalty_multiplier_msat: 1_000, ..Default::default()
+                       base_penalty_msat: 500, liquidity_penalty_multiplier_msat: 1_000,
+                       anti_probing_penalty_msat: 0, ..Default::default()
                };
                let scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 558);
+
+               let params = ProbabilisticScoringParameters {
+                       base_penalty_msat: 500, liquidity_penalty_multiplier_msat: 1_000,
+                       base_penalty_amount_multiplier_msat: (1 << 30),
+                       anti_probing_penalty_msat: 0, ..Default::default()
+               };
+
+               let scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 558 + 128);
        }
 
        #[test]
        fn adds_amount_penalty_to_liquidity_penalty() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let source = source_node_id();
                let target = target_node_id();
                let usage = ChannelUsage {
                        amount_msat: 512_000,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: Some(1_000) },
                };
 
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
-                       amount_penalty_multiplier_msat: 0,
+                       liquidity_penalty_amount_multiplier_msat: 0,
                        ..ProbabilisticScoringParameters::zero_penalty()
                };
                let scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
@@ -2528,7 +2223,7 @@ mod tests {
 
                let params = ProbabilisticScoringParameters {
                        liquidity_penalty_multiplier_msat: 1_000,
-                       amount_penalty_multiplier_msat: 256,
+                       liquidity_penalty_amount_multiplier_msat: 256,
                        ..ProbabilisticScoringParameters::zero_penalty()
                };
                let scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
@@ -2538,7 +2233,7 @@ mod tests {
        #[test]
        fn calculates_log10_without_overflowing_u64_max_value() {
                let logger = TestLogger::new();
-               let network_graph = network_graph();
+               let network_graph = network_graph(&logger);
                let source = source_node_id();
                let target = target_node_id();
                let usage = ChannelUsage {
@@ -2557,9 +2252,12 @@ mod tests {
 
        #[test]
        fn accounts_for_inflight_htlc_usage() {
-               let network_graph = network_graph();
                let logger = TestLogger::new();
-               let params = ProbabilisticScoringParameters::default();
+               let network_graph = network_graph(&logger);
+               let params = ProbabilisticScoringParameters {
+                       considered_impossible_penalty_msat: u64::max_value(),
+                       ..ProbabilisticScoringParameters::zero_penalty()
+               };
                let scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
                let source = source_node_id();
                let target = target_node_id();
@@ -2567,11 +2265,80 @@ mod tests {
                let usage = ChannelUsage {
                        amount_msat: 750,
                        inflight_htlc_msat: 0,
-                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000 },
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: Some(1_000) },
                };
                assert_ne!(scorer.channel_penalty_msat(42, &source, &target, usage), u64::max_value());
 
                let usage = ChannelUsage { inflight_htlc_msat: 251, ..usage };
                assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), u64::max_value());
        }
+
+       #[test]
+       fn removes_uncertainity_when_exact_liquidity_known() {
+               let logger = TestLogger::new();
+               let network_graph = network_graph(&logger);
+               let params = ProbabilisticScoringParameters::default();
+               let scorer = ProbabilisticScorer::new(params.clone(), &network_graph, &logger);
+               let source = source_node_id();
+               let target = target_node_id();
+
+               let base_penalty_msat = params.base_penalty_msat;
+               let usage = ChannelUsage {
+                       amount_msat: 750,
+                       inflight_htlc_msat: 0,
+                       effective_capacity: EffectiveCapacity::ExactLiquidity { liquidity_msat: 1_000 },
+               };
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), base_penalty_msat);
+
+               let usage = ChannelUsage { amount_msat: 1_000, ..usage };
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), base_penalty_msat);
+
+               let usage = ChannelUsage { amount_msat: 1_001, ..usage };
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), u64::max_value());
+       }
+
+       #[test]
+       fn adds_anti_probing_penalty() {
+               let logger = TestLogger::new();
+               let network_graph = network_graph(&logger);
+               let source = source_node_id();
+               let target = target_node_id();
+               let params = ProbabilisticScoringParameters {
+                       anti_probing_penalty_msat: 500,
+                       ..ProbabilisticScoringParameters::zero_penalty()
+               };
+               let scorer = ProbabilisticScorer::new(params, &network_graph, &logger);
+
+               // Check we receive no penalty for a low htlc_maximum_msat.
+               let usage = ChannelUsage {
+                       amount_msat: 512_000,
+                       inflight_htlc_msat: 0,
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: Some(1_000) },
+               };
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 0);
+
+               // Check we receive anti-probing penalty for htlc_maximum_msat == channel_capacity.
+               let usage = ChannelUsage {
+                       amount_msat: 512_000,
+                       inflight_htlc_msat: 0,
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: Some(1_024_000) },
+               };
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 500);
+
+               // Check we receive anti-probing penalty for htlc_maximum_msat == channel_capacity/2.
+               let usage = ChannelUsage {
+                       amount_msat: 512_000,
+                       inflight_htlc_msat: 0,
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: Some(512_000) },
+               };
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 500);
+
+               // Check we receive no anti-probing penalty for htlc_maximum_msat == channel_capacity/2 - 1.
+               let usage = ChannelUsage {
+                       amount_msat: 512_000,
+                       inflight_htlc_msat: 0,
+                       effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: Some(511_999) },
+               };
+               assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 0);
+       }
 }