Merge pull request #1227 from jkczyz/2021-12-probabilistic-scorer
authorvalentinewallace <valentinewallace@users.noreply.github.com>
Thu, 3 Feb 2022 15:50:49 +0000 (10:50 -0500)
committerGitHub <noreply@github.com>
Thu, 3 Feb 2022 15:50:49 +0000 (10:50 -0500)
Probabilistic channel scoring

14 files changed:
fuzz/src/full_stack.rs
fuzz/src/router.rs
lightning-background-processor/src/lib.rs
lightning-invoice/src/payment.rs
lightning-invoice/src/utils.rs
lightning/src/ln/channelmanager.rs
lightning/src/ln/functional_test_utils.rs
lightning/src/ln/functional_tests.rs
lightning/src/ln/payment_tests.rs
lightning/src/ln/shutdown_tests.rs
lightning/src/routing/network_graph.rs
lightning/src/routing/router.rs
lightning/src/routing/scoring.rs
lightning/src/util/test_utils.rs

index 7db5aadcdd7a260c7704caf4fb247568cedaae16..9db04b645e4143496a921eac2cd4a1d0bc83ae37 100644 (file)
@@ -39,7 +39,7 @@ use lightning::ln::msgs::DecodeError;
 use lightning::ln::script::ShutdownScript;
 use lightning::routing::network_graph::{NetGraphMsgHandler, NetworkGraph};
 use lightning::routing::router::{find_route, PaymentParameters, RouteParameters};
-use lightning::routing::scoring::Scorer;
+use lightning::routing::scoring::FixedPenaltyScorer;
 use lightning::util::config::UserConfig;
 use lightning::util::errors::APIError;
 use lightning::util::events::Event;
@@ -393,7 +393,7 @@ pub fn do_test(data: &[u8], logger: &Arc<dyn Logger>) {
        let our_id = PublicKey::from_secret_key(&Secp256k1::signing_only(), &keys_manager.get_node_secret());
        let network_graph = Arc::new(NetworkGraph::new(genesis_block(network).block_hash()));
        let net_graph_msg_handler = Arc::new(NetGraphMsgHandler::new(Arc::clone(&network_graph), None, Arc::clone(&logger)));
-       let scorer = Scorer::with_fixed_penalty(0);
+       let scorer = FixedPenaltyScorer::with_penalty(0);
 
        let peers = RefCell::new([false; 256]);
        let mut loss_detector = MoneyLossDetector::new(&peers, channelmanager.clone(), monitor.clone(), PeerManager::new(MessageHandler {
index efa244d9bf5cb6eb4715730fff3f2baca5f9f2f7..095059c5183676232c48b36093a244a9fe69ba3b 100644 (file)
@@ -17,7 +17,7 @@ use lightning::ln::channelmanager::{ChannelDetails, ChannelCounterparty};
 use lightning::ln::features::InitFeatures;
 use lightning::ln::msgs;
 use lightning::routing::router::{find_route, PaymentParameters, RouteHint, RouteHintHop, RouteParameters};
-use lightning::routing::scoring::Scorer;
+use lightning::routing::scoring::FixedPenaltyScorer;
 use lightning::util::logger::Logger;
 use lightning::util::ser::Readable;
 use lightning::routing::network_graph::{NetworkGraph, RoutingFees};
@@ -249,7 +249,7 @@ pub fn do_test<Out: test_logger::Output>(data: &[u8], out: Out) {
                                                }]));
                                        }
                                }
-                               let scorer = Scorer::with_fixed_penalty(0);
+                               let scorer = FixedPenaltyScorer::with_penalty(0);
                                for target in node_pks.iter() {
                                        let route_params = RouteParameters {
                                                payment_params: PaymentParameters::from_node_id(*target).with_route_hints(last_hops.clone()),
index b60dc6c830432c47777faa4a7b84db9e666ba954..6e5e60e5014f207374fdca8bbb8ddf87db027a72 100644 (file)
@@ -673,7 +673,7 @@ mod tests {
                let data_dir = nodes[0].persister.get_data_dir();
                let persister = move |node: &ChannelManager<InMemorySigner, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
                let router = DefaultRouter::new(Arc::clone(&nodes[0].network_graph), Arc::clone(&nodes[0].logger));
-               let scorer = Arc::new(Mutex::new(test_utils::TestScorer::default()));
+               let scorer = Arc::new(Mutex::new(test_utils::TestScorer::with_penalty(0)));
                let invoice_payer = Arc::new(InvoicePayer::new(Arc::clone(&nodes[0].node), router, scorer, Arc::clone(&nodes[0].logger), |_: &_| {}, RetryAttempts(2)));
                let event_handler = Arc::clone(&invoice_payer);
                let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].net_graph_msg_handler.clone(), nodes[0].peer_manager.clone(), nodes[0].logger.clone());
index f2486969e769d53d9f23c9864aaf4963b6378c67..82c07199f0db871c1498fb64a21e63603aec2084 100644 (file)
@@ -90,7 +90,7 @@
 //! # }
 //! # impl Score for FakeScorer {
 //! #     fn channel_penalty_msat(
-//! #         &self, _short_channel_id: u64, _send_amt: u64, _chan_amt: Option<u64>, _source: &NodeId, _target: &NodeId
+//! #         &self, _short_channel_id: u64, _send_amt: u64, _chan_amt: u64, _source: &NodeId, _target: &NodeId
 //! #     ) -> u64 { 0 }
 //! #     fn payment_path_failed(&mut self, _path: &[&RouteHop], _short_channel_id: u64) {}
 //! #     fn payment_path_successful(&mut self, _path: &[&RouteHop]) {}
@@ -1327,7 +1327,7 @@ mod tests {
 
        impl Score for TestScorer {
                fn channel_penalty_msat(
-                       &self, _short_channel_id: u64, _send_amt: u64, _chan_amt: Option<u64>, _source: &NodeId, _target: &NodeId
+                       &self, _short_channel_id: u64, _send_amt: u64, _chan_amt: u64, _source: &NodeId, _target: &NodeId
                ) -> u64 { 0 }
 
                fn payment_path_failed(&mut self, actual_path: &[&RouteHop], actual_short_channel_id: u64) {
index 390290768de7da76bc94d9f87da58b9e3044669a..ef95b3e355b5abd1c91303e3e708b2014041482a 100644 (file)
@@ -227,7 +227,7 @@ mod test {
                let first_hops = nodes[0].node.list_usable_channels();
                let network_graph = node_cfgs[0].network_graph;
                let logger = test_utils::TestLogger::new();
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let route = find_route(
                        &nodes[0].node.get_our_node_id(), &route_params, network_graph,
                        Some(&first_hops.iter().collect::<Vec<_>>()), &logger, &scorer,
index 2097dfda9f187a56eb652e1c8122eab1185e6a12..451d6d5f8efab76b6273f91927eee7c091c004e1 100644 (file)
@@ -6901,7 +6901,7 @@ mod tests {
                let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
                let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
                create_announced_chan_between_nodes(&nodes, 0, 1, InitFeatures::known(), InitFeatures::known());
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
 
                // To start (1), send a regular payment but don't claim it.
                let expected_route = [&nodes[1]];
@@ -7006,7 +7006,7 @@ mod tests {
                };
                let network_graph = nodes[0].network_graph;
                let first_hops = nodes[0].node.list_usable_channels();
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let route = find_route(
                        &payer_pubkey, &route_params, network_graph, Some(&first_hops.iter().collect::<Vec<_>>()),
                        nodes[0].logger, &scorer
@@ -7049,7 +7049,7 @@ mod tests {
                };
                let network_graph = nodes[0].network_graph;
                let first_hops = nodes[0].node.list_usable_channels();
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let route = find_route(
                        &payer_pubkey, &route_params, network_graph, Some(&first_hops.iter().collect::<Vec<_>>()),
                        nodes[0].logger, &scorer
@@ -7143,7 +7143,6 @@ pub mod bench {
        use ln::msgs::{ChannelMessageHandler, Init};
        use routing::network_graph::NetworkGraph;
        use routing::router::{PaymentParameters, get_route};
-       use routing::scoring::Scorer;
        use util::test_utils;
        use util::config::UserConfig;
        use util::events::{Event, MessageSendEvent, MessageSendEventsProvider, PaymentPurpose};
@@ -7253,7 +7252,7 @@ pub mod bench {
                                let usable_channels = $node_a.list_usable_channels();
                                let payment_params = PaymentParameters::from_node_id($node_b.get_our_node_id())
                                        .with_features(InvoiceFeatures::known());
-                               let scorer = Scorer::with_fixed_penalty(0);
+                               let scorer = test_utils::TestScorer::with_penalty(0);
                                let route = get_route(&$node_a.get_our_node_id(), &payment_params, &dummy_graph,
                                        Some(&usable_channels.iter().map(|r| r).collect::<Vec<_>>()), 10_000, TEST_FINAL_CLTV, &logger_a, &scorer).unwrap();
 
index b7d7011c93341e9b779fdbf4c4734db90e300caf..e8931c1edc00f9f0f3156e3515c512e594e963e2 100644 (file)
@@ -1085,7 +1085,7 @@ macro_rules! get_route_and_payment_hash {
                let payment_params = $crate::routing::router::PaymentParameters::from_node_id($recv_node.node.get_our_node_id())
                        .with_features($crate::ln::features::InvoiceFeatures::known())
                        .with_route_hints($last_hops);
-               let scorer = $crate::util::test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = $crate::util::test_utils::TestScorer::with_penalty(0);
                let route = $crate::routing::router::get_route(
                        &$send_node.node.get_our_node_id(), &payment_params, $send_node.network_graph,
                        Some(&$send_node.node.list_usable_channels().iter().collect::<Vec<_>>()),
@@ -1540,7 +1540,7 @@ pub const TEST_FINAL_CLTV: u32 = 70;
 pub fn route_payment<'a, 'b, 'c>(origin_node: &Node<'a, 'b, 'c>, expected_route: &[&Node<'a, 'b, 'c>], recv_value: u64) -> (PaymentPreimage, PaymentHash, PaymentSecret) {
        let payment_params = PaymentParameters::from_node_id(expected_route.last().unwrap().node.get_our_node_id())
                .with_features(InvoiceFeatures::known());
-       let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+       let scorer = test_utils::TestScorer::with_penalty(0);
        let route = get_route(
                &origin_node.node.get_our_node_id(), &payment_params, &origin_node.network_graph,
                Some(&origin_node.node.list_usable_channels().iter().collect::<Vec<_>>()),
@@ -1558,7 +1558,7 @@ pub fn route_payment<'a, 'b, 'c>(origin_node: &Node<'a, 'b, 'c>, expected_route:
 pub fn route_over_limit<'a, 'b, 'c>(origin_node: &Node<'a, 'b, 'c>, expected_route: &[&Node<'a, 'b, 'c>], recv_value: u64)  {
        let payment_params = PaymentParameters::from_node_id(expected_route.last().unwrap().node.get_our_node_id())
                .with_features(InvoiceFeatures::known());
-       let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+       let scorer = test_utils::TestScorer::with_penalty(0);
        let route = get_route(
                &origin_node.node.get_our_node_id(), &payment_params, origin_node.network_graph, 
                None, recv_value, TEST_FINAL_CLTV, origin_node.logger, &scorer).unwrap();
index 6f6e51a6f98313039f1b7e3e723d2c9602144864..fc527ddce954fe0dc6dcb9ec693b741ee8424270 100644 (file)
@@ -7439,7 +7439,7 @@ fn test_check_htlc_underpaying() {
        // Create some initial channels
        create_announced_chan_between_nodes(&nodes, 0, 1, InitFeatures::known(), InitFeatures::known());
 
-       let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+       let scorer = test_utils::TestScorer::with_penalty(0);
        let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id()).with_features(InvoiceFeatures::known());
        let route = get_route(&nodes[0].node.get_our_node_id(), &payment_params, nodes[0].network_graph, None, 10_000, TEST_FINAL_CLTV, nodes[0].logger, &scorer).unwrap();
        let (_, our_payment_hash, _) = get_payment_preimage_hash!(nodes[0]);
@@ -7842,7 +7842,7 @@ fn test_bump_penalty_txn_on_revoked_htlcs() {
        let chan = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1000000, 59000000, InitFeatures::known(), InitFeatures::known());
        // Lock HTLC in both directions (using a slightly lower CLTV delay to provide timely RBF bumps)
        let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id()).with_features(InvoiceFeatures::known());
-       let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+       let scorer = test_utils::TestScorer::with_penalty(0);
        let route = get_route(&nodes[0].node.get_our_node_id(), &payment_params, &nodes[0].network_graph, None,
                3_000_000, 50, nodes[0].logger, &scorer).unwrap();
        let payment_preimage = send_along_route(&nodes[0], route, &[&nodes[1]], 3_000_000).0;
@@ -9379,7 +9379,7 @@ fn test_keysend_payments_to_public_node() {
                final_value_msat: 10000,
                final_cltv_expiry_delta: 40,
        };
-       let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+       let scorer = test_utils::TestScorer::with_penalty(0);
        let route = find_route(&payer_pubkey, &route_params, network_graph, None, nodes[0].logger, &scorer).unwrap();
 
        let test_preimage = PaymentPreimage([42; 32]);
@@ -9413,7 +9413,7 @@ fn test_keysend_payments_to_private_node() {
        };
        let network_graph = nodes[0].network_graph;
        let first_hops = nodes[0].node.list_usable_channels();
-       let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+       let scorer = test_utils::TestScorer::with_penalty(0);
        let route = find_route(
                &payer_pubkey, &route_params, network_graph, Some(&first_hops.iter().collect::<Vec<_>>()),
                nodes[0].logger, &scorer
index a86676422ed8df71faabd0b4ae7295cd1e4ed8c6..2435c3b7a970fcd4f75140ca96c731ed9db495a5 100644 (file)
@@ -723,7 +723,7 @@ fn get_ldk_payment_preimage() {
 
        let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id())
                .with_features(InvoiceFeatures::known());
-       let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+       let scorer = test_utils::TestScorer::with_penalty(0);
        let route = get_route(
                &nodes[0].node.get_our_node_id(), &payment_params, &nodes[0].network_graph,
                Some(&nodes[0].node.list_usable_channels().iter().collect::<Vec<_>>()),
index 7cfca4b86fb26151083a6f67dbebe8c47091cfe6..a687df8886ca3f7193339e8120618152cd0722b6 100644 (file)
@@ -76,7 +76,7 @@ fn updates_shutdown_wait() {
        let chan_1 = create_announced_chan_between_nodes(&nodes, 0, 1, InitFeatures::known(), InitFeatures::known());
        let chan_2 = create_announced_chan_between_nodes(&nodes, 1, 2, InitFeatures::known(), InitFeatures::known());
        let logger = test_utils::TestLogger::new();
-       let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+       let scorer = test_utils::TestScorer::with_penalty(0);
 
        let (payment_preimage, _, _) = route_payment(&nodes[0], &[&nodes[1], &nodes[2]], 100000);
 
index a26b549b43d45de4d96cc91ddf3d32921c241f3b..ee310830afa93ee8e4bc55cccba603cf26897ac2 100644 (file)
@@ -593,9 +593,8 @@ where
 }
 
 #[derive(Clone, Debug, PartialEq)]
-/// Details about one direction of a channel. Received
-/// within a channel update.
-pub struct DirectionalChannelInfo {
+/// Details about one direction of a channel as received within a [`ChannelUpdate`].
+pub struct ChannelUpdateInfo {
        /// When the last update to the channel direction was issued.
        /// Value is opaque, as set in the announcement.
        pub last_update: u32,
@@ -616,14 +615,14 @@ pub struct DirectionalChannelInfo {
        pub last_update_message: Option<ChannelUpdate>,
 }
 
-impl fmt::Display for DirectionalChannelInfo {
+impl fmt::Display for ChannelUpdateInfo {
        fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
                write!(f, "last_update {}, enabled {}, cltv_expiry_delta {}, htlc_minimum_msat {}, fees {:?}", self.last_update, self.enabled, self.cltv_expiry_delta, self.htlc_minimum_msat, self.fees)?;
                Ok(())
        }
 }
 
-impl_writeable_tlv_based!(DirectionalChannelInfo, {
+impl_writeable_tlv_based!(ChannelUpdateInfo, {
        (0, last_update, required),
        (2, enabled, required),
        (4, cltv_expiry_delta, required),
@@ -642,11 +641,11 @@ pub struct ChannelInfo {
        /// Source node of the first direction of a channel
        pub node_one: NodeId,
        /// Details about the first direction of a channel
-       pub one_to_two: Option<DirectionalChannelInfo>,
+       pub one_to_two: Option<ChannelUpdateInfo>,
        /// Source node of the second direction of a channel
        pub node_two: NodeId,
        /// Details about the second direction of a channel
-       pub two_to_one: Option<DirectionalChannelInfo>,
+       pub two_to_one: Option<ChannelUpdateInfo>,
        /// The channel capacity as seen on-chain, if chain lookup is available.
        pub capacity_sats: Option<u64>,
        /// An initial announcement of the channel
@@ -660,6 +659,23 @@ pub struct ChannelInfo {
        announcement_received_time: u64,
 }
 
+impl ChannelInfo {
+       /// Returns a [`DirectedChannelInfo`] for the channel directed to the given `target` from a
+       /// returned `source`, or `None` if `target` is not one of the channel's counterparties.
+       pub fn as_directed_to(&self, target: &NodeId) -> Option<(DirectedChannelInfo, &NodeId)> {
+               let (direction, source) = {
+                       if target == &self.node_one {
+                               (self.two_to_one.as_ref(), &self.node_two)
+                       } else if target == &self.node_two {
+                               (self.one_to_two.as_ref(), &self.node_one)
+                       } else {
+                               return None;
+                       }
+               };
+               Some((DirectedChannelInfo { channel: self, direction }, source))
+       }
+}
+
 impl fmt::Display for ChannelInfo {
        fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
                write!(f, "features: {}, node_one: {}, one_to_two: {:?}, node_two: {}, two_to_one: {:?}",
@@ -679,6 +695,132 @@ impl_writeable_tlv_based!(ChannelInfo, {
        (12, announcement_message, required),
 });
 
+/// A wrapper around [`ChannelInfo`] representing information about the channel as directed from a
+/// source node to a target node.
+#[derive(Clone)]
+pub struct DirectedChannelInfo<'a> {
+       channel: &'a ChannelInfo,
+       direction: Option<&'a ChannelUpdateInfo>,
+}
+
+impl<'a> DirectedChannelInfo<'a> {
+       /// Returns information for the channel.
+       pub fn channel(&self) -> &'a ChannelInfo { self.channel }
+
+       /// Returns information for the direction.
+       pub fn direction(&self) -> Option<&'a ChannelUpdateInfo> { self.direction }
+
+       /// Returns the [`EffectiveCapacity`] of the channel in the direction.
+       ///
+       /// This is either the total capacity from the funding transaction, if known, or the
+       /// `htlc_maximum_msat` for the direction as advertised by the gossip network, if known,
+       /// whichever is smaller.
+       pub fn effective_capacity(&self) -> EffectiveCapacity {
+               let capacity_msat = self.channel.capacity_sats.map(|capacity_sats| capacity_sats * 1000);
+               self.direction
+                       .and_then(|direction| direction.htlc_maximum_msat)
+                       .map(|max_htlc_msat| {
+                               let capacity_msat = capacity_msat.unwrap_or(u64::max_value());
+                               if max_htlc_msat < capacity_msat {
+                                       EffectiveCapacity::MaximumHTLC { amount_msat: max_htlc_msat }
+                               } else {
+                                       EffectiveCapacity::Total { capacity_msat }
+                               }
+                       })
+                       .or_else(|| capacity_msat.map(|capacity_msat|
+                                       EffectiveCapacity::Total { capacity_msat }))
+                       .unwrap_or(EffectiveCapacity::Unknown)
+       }
+
+       /// Returns `Some` if [`ChannelUpdateInfo`] is available in the direction.
+       pub(super) fn with_update(self) -> Option<DirectedChannelInfoWithUpdate<'a>> {
+               match self.direction {
+                       Some(_) => Some(DirectedChannelInfoWithUpdate { inner: self }),
+                       None => None,
+               }
+       }
+}
+
+impl<'a> fmt::Debug for DirectedChannelInfo<'a> {
+       fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+               f.debug_struct("DirectedChannelInfo")
+                       .field("channel", &self.channel)
+                       .finish()
+       }
+}
+
+/// A [`DirectedChannelInfo`] with [`ChannelUpdateInfo`] available in its direction.
+#[derive(Clone)]
+pub(super) struct DirectedChannelInfoWithUpdate<'a> {
+       inner: DirectedChannelInfo<'a>,
+}
+
+impl<'a> DirectedChannelInfoWithUpdate<'a> {
+       /// Returns information for the channel.
+       #[inline]
+       pub(super) fn channel(&self) -> &'a ChannelInfo { &self.inner.channel }
+
+       /// Returns information for the direction.
+       #[inline]
+       pub(super) fn direction(&self) -> &'a ChannelUpdateInfo { self.inner.direction.unwrap() }
+
+       /// Returns the [`EffectiveCapacity`] of the channel in the direction.
+       #[inline]
+       pub(super) fn effective_capacity(&self) -> EffectiveCapacity { self.inner.effective_capacity() }
+}
+
+impl<'a> fmt::Debug for DirectedChannelInfoWithUpdate<'a> {
+       fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+               self.inner.fmt(f)
+       }
+}
+
+/// The effective capacity of a channel for routing purposes.
+///
+/// While this may be smaller than the actual channel capacity, amounts greater than
+/// [`Self::as_msat`] should not be routed through the channel.
+pub enum EffectiveCapacity {
+       /// The available liquidity in the channel known from being a channel counterparty, and thus a
+       /// direct hop.
+       ExactLiquidity {
+               /// Either the inbound or outbound liquidity depending on the direction, denominated in
+               /// millisatoshi.
+               liquidity_msat: u64,
+       },
+       /// The maximum HTLC amount in one direction as advertised on the gossip network.
+       MaximumHTLC {
+               /// The maximum HTLC amount denominated in millisatoshi.
+               amount_msat: u64,
+       },
+       /// The total capacity of the channel as determined by the funding transaction.
+       Total {
+               /// The funding amount denominated in millisatoshi.
+               capacity_msat: u64,
+       },
+       /// A capacity sufficient to route any payment, typically used for private channels provided by
+       /// an invoice.
+       Infinite,
+       /// A capacity that is unknown possibly because either the chain state is unavailable to know
+       /// the total capacity or the `htlc_maximum_msat` was not advertised on the gossip network.
+       Unknown,
+}
+
+/// The presumed channel capacity denominated in millisatoshi for [`EffectiveCapacity::Unknown`] to
+/// use when making routing decisions.
+pub const UNKNOWN_CHANNEL_CAPACITY_MSAT: u64 = 250_000 * 1000;
+
+impl EffectiveCapacity {
+       /// Returns the effective capacity denominated in millisatoshi.
+       pub fn as_msat(&self) -> u64 {
+               match self {
+                       EffectiveCapacity::ExactLiquidity { liquidity_msat } => *liquidity_msat,
+                       EffectiveCapacity::MaximumHTLC { amount_msat } => *amount_msat,
+                       EffectiveCapacity::Total { capacity_msat } => *capacity_msat,
+                       EffectiveCapacity::Infinite => u64::max_value(),
+                       EffectiveCapacity::Unknown => UNKNOWN_CHANNEL_CAPACITY_MSAT,
+               }
+       }
+}
 
 /// Fees for routing via a given channel or a node
 #[derive(Eq, PartialEq, Copy, Clone, Debug, Hash)]
@@ -1227,7 +1369,7 @@ impl NetworkGraph {
                                                let last_update_message = if msg.excess_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY
                                                        { full_msg.cloned() } else { None };
 
-                                               let updated_channel_dir_info = DirectionalChannelInfo {
+                                               let updated_channel_update_info = ChannelUpdateInfo {
                                                        enabled: chan_enabled,
                                                        last_update: msg.timestamp,
                                                        cltv_expiry_delta: msg.cltv_expiry_delta,
@@ -1239,7 +1381,7 @@ impl NetworkGraph {
                                                        },
                                                        last_update_message
                                                };
-                                               $target = Some(updated_channel_dir_info);
+                                               $target = Some(updated_channel_update_info);
                                        }
                                }
 
index cf2afbbbadb7e0baabba60d1f4f17e24799a8e03..a21cf79a144dfecf47603da633f887992b068d5b 100644 (file)
@@ -18,7 +18,7 @@ use ln::channelmanager::ChannelDetails;
 use ln::features::{ChannelFeatures, InvoiceFeatures, NodeFeatures};
 use ln::msgs::{DecodeError, ErrorAction, LightningError, MAX_VALUE_MSAT};
 use routing::scoring::Score;
-use routing::network_graph::{NetworkGraph, NodeId, RoutingFees};
+use routing::network_graph::{DirectedChannelInfoWithUpdate, EffectiveCapacity, NetworkGraph, NodeId, RoutingFees};
 use util::ser::{Writeable, Readable};
 use util::logger::{Level, Logger};
 
@@ -344,11 +344,79 @@ impl cmp::PartialOrd for RouteGraphNode {
        }
 }
 
-struct DummyDirectionalChannelInfo {
-       cltv_expiry_delta: u32,
-       htlc_minimum_msat: u64,
-       htlc_maximum_msat: Option<u64>,
-       fees: RoutingFees,
+/// A wrapper around the various hop representations.
+///
+/// Used to construct a [`PathBuildingHop`] and to estimate [`EffectiveCapacity`].
+#[derive(Clone, Debug)]
+enum CandidateRouteHop<'a> {
+       /// A hop from the payer, where the outbound liquidity is known.
+       FirstHop {
+               details: &'a ChannelDetails,
+       },
+       /// A hop found in the [`NetworkGraph`], where the channel capacity may or may not be known.
+       PublicHop {
+               info: DirectedChannelInfoWithUpdate<'a>,
+               short_channel_id: u64,
+       },
+       /// A hop to the payee found in the payment invoice, though not necessarily a direct channel.
+       PrivateHop {
+               hint: &'a RouteHintHop,
+       }
+}
+
+impl<'a> CandidateRouteHop<'a> {
+       fn short_channel_id(&self) -> u64 {
+               match self {
+                       CandidateRouteHop::FirstHop { details } => details.short_channel_id.unwrap(),
+                       CandidateRouteHop::PublicHop { short_channel_id, .. } => *short_channel_id,
+                       CandidateRouteHop::PrivateHop { hint } => hint.short_channel_id,
+               }
+       }
+
+       // 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(),
+               }
+       }
+
+       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,
+               }
+       }
+
+       fn htlc_minimum_msat(&self) -> u64 {
+               match self {
+                       CandidateRouteHop::FirstHop { .. } => 0,
+                       CandidateRouteHop::PublicHop { info, .. } => info.direction().htlc_minimum_msat,
+                       CandidateRouteHop::PrivateHop { hint } => hint.htlc_minimum_msat.unwrap_or(0),
+               }
+       }
+
+       fn fees(&self) -> RoutingFees {
+               match self {
+                       CandidateRouteHop::FirstHop { .. } => RoutingFees {
+                               base_msat: 0, proportional_millionths: 0,
+                       },
+                       CandidateRouteHop::PublicHop { info, .. } => info.direction().fees,
+                       CandidateRouteHop::PrivateHop { hint } => hint.fees,
+               }
+       }
+
+       fn effective_capacity(&self) -> EffectiveCapacity {
+               match self {
+                       CandidateRouteHop::FirstHop { details } => EffectiveCapacity::ExactLiquidity {
+                               liquidity_msat: details.outbound_capacity_msat,
+                       },
+                       CandidateRouteHop::PublicHop { info, .. } => info.effective_capacity(),
+                       CandidateRouteHop::PrivateHop { .. } => EffectiveCapacity::Infinite,
+               }
+       }
 }
 
 /// It's useful to keep track of the hops associated with the fees required to use them,
@@ -357,21 +425,17 @@ struct DummyDirectionalChannelInfo {
 /// These fee values are useful to choose hops as we traverse the graph "payee-to-payer".
 #[derive(Clone, Debug)]
 struct PathBuildingHop<'a> {
-       // The RouteHintHop fields which will eventually be used if this hop is used in a final Route.
-       // Note that node_features is calculated separately after our initial graph walk.
+       // Note that this should be dropped in favor of loading it from CandidateRouteHop, but doing so
+       // is a larger refactor and will require careful performance analysis.
        node_id: NodeId,
-       short_channel_id: u64,
-       channel_features: &'a ChannelFeatures,
+       candidate: CandidateRouteHop<'a>,
        fee_msat: u64,
-       cltv_expiry_delta: u32,
 
        /// Minimal fees required to route to the source node of the current hop via any of its inbound channels.
        src_lowest_inbound_fees: RoutingFees,
-       /// Fees of the channel used in this hop.
-       channel_fees: RoutingFees,
        /// 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 channel_fees).
+       /// 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,
        /// Used to compare channels when choosing the for routing.
@@ -379,10 +443,6 @@ struct PathBuildingHop<'a> {
        /// an estimated cost of reaching this hop.
        /// Might get stale when fees are recomputed. Primarily for internal use.
        total_fee_msat: u64,
-       /// This is useful for update_value_and_recompute_fees to make sure
-       /// we don't fall below the minimum. Should not be updated manually and
-       /// generally should not be accessed.
-       htlc_minimum_msat: u64,
        /// A mirror of the same field in RouteGraphNode. Note that this is only used during the graph
        /// walk and may be invalid thereafter.
        path_htlc_minimum_msat: u64,
@@ -461,7 +521,7 @@ impl<'a> PaymentPath<'a> {
                        // set it too high just to maliciously take more fees by exploiting this
                        // match htlc_minimum_msat logic.
                        let mut cur_hop_transferred_amount_msat = total_fee_paid_msat + value_msat;
-                       if let Some(extra_fees_msat) = cur_hop.htlc_minimum_msat.checked_sub(cur_hop_transferred_amount_msat) {
+                       if let Some(extra_fees_msat) = cur_hop.candidate.htlc_minimum_msat().checked_sub(cur_hop_transferred_amount_msat) {
                                // Note that there is a risk that *previous hops* (those closer to us, as we go
                                // payee->our_node here) would exceed their htlc_maximum_msat or available balance.
                                //
@@ -489,7 +549,7 @@ impl<'a> PaymentPath<'a> {
                        // Irrelevant for the first hop, as it doesn't have the previous hop, and the use of
                        // this channel is free for us.
                        if i != 0 {
-                               if let Some(new_fee) = compute_fees(cur_hop_transferred_amount_msat, cur_hop.channel_fees) {
+                               if let Some(new_fee) = compute_fees(cur_hop_transferred_amount_msat, cur_hop.candidate.fees()) {
                                        cur_hop.hop_use_fee_msat = new_fee;
                                        total_fee_paid_msat += new_fee;
                                } else {
@@ -648,15 +708,6 @@ where L::Target: Logger {
        let network_graph = network.read_only();
        let network_channels = network_graph.channels();
        let network_nodes = network_graph.nodes();
-       let dummy_directional_info = DummyDirectionalChannelInfo { // used for first_hops routes
-               cltv_expiry_delta: 0,
-               htlc_minimum_msat: 0,
-               htlc_maximum_msat: None,
-               fees: RoutingFees {
-                       base_msat: 0,
-                       proportional_millionths: 0,
-               }
-       };
 
        // Allow MPP only if we have a features set from somewhere that indicates the payee supports
        // it. If the payee supports it they're supposed to include it in the invoice, so that should
@@ -675,24 +726,26 @@ where L::Target: Logger {
        // Prepare the data we'll use for payee-to-payer search by
        // inserting first hops suggested by the caller as targets.
        // Our search will then attempt to reach them while traversing from the payee node.
-       let mut first_hop_targets: HashMap<_, Vec<(_, ChannelFeatures, _, NodeFeatures)>> =
+       let mut first_hop_targets: HashMap<_, Vec<&ChannelDetails>> =
                HashMap::with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 });
        if let Some(hops) = first_hops {
                for chan in hops {
-                       let short_channel_id = chan.short_channel_id.expect("first_hops should be filled in with usable channels, not pending ones");
+                       if chan.short_channel_id.is_none() {
+                               panic!("first_hops should be filled in with usable channels, not pending ones");
+                       }
                        if chan.counterparty.node_id == *our_node_pubkey {
                                return Err(LightningError{err: "First hop cannot have our_node_pubkey as a destination.".to_owned(), action: ErrorAction::IgnoreError});
                        }
-                       first_hop_targets.entry(NodeId::from_pubkey(&chan.counterparty.node_id)).or_insert(Vec::new())
-                               .push((short_channel_id, chan.counterparty.features.to_context(), chan.outbound_capacity_msat, chan.counterparty.features.to_context()));
+                       first_hop_targets
+                               .entry(NodeId::from_pubkey(&chan.counterparty.node_id))
+                               .or_insert(Vec::new())
+                               .push(chan);
                }
                if first_hop_targets.is_empty() {
                        return Err(LightningError{err: "Cannot route when there are no outbound routes away from us".to_owned(), action: ErrorAction::IgnoreError});
                }
        }
 
-       let empty_channel_features = ChannelFeatures::empty();
-
        // The main heap containing all candidate next-hops sorted by their score (max(A* 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.
@@ -731,42 +784,24 @@ where L::Target: Logger {
        log_trace!(logger, "Building path from {} (payee) to {} (us/payer) for value {} msat.", payment_params.payee_pubkey, our_node_pubkey, final_value_msat);
 
        macro_rules! add_entry {
-               // Adds entry which goes from $src_node_id to $dest_node_id
-               // over the channel with id $chan_id with fees described in
-               // $directional_info.
+               // Adds entry which goes from $src_node_id to $dest_node_id over the $candidate hop.
                // $next_hops_fee_msat represents the fees paid for using all the channels *after* this one,
                // since that value has to be transferred over this channel.
                // Returns whether this channel caused an update to `targets`.
-               ( $chan_id: expr, $src_node_id: expr, $dest_node_id: expr, $directional_info: expr, $capacity_sats: expr, $chan_features: expr, $next_hops_fee_msat: expr,
-                  $next_hops_value_contribution: expr, $next_hops_path_htlc_minimum_msat: expr, $next_hops_path_penalty_msat: expr, $next_hops_cltv_delta: expr ) => { {
+               ( $candidate: expr, $src_node_id: expr, $dest_node_id: expr, $next_hops_fee_msat: expr,
+                  $next_hops_value_contribution: expr, $next_hops_path_htlc_minimum_msat: expr,
+                  $next_hops_path_penalty_msat: expr, $next_hops_cltv_delta: expr ) => { {
                        // We "return" whether we updated the path at the end, via this:
                        let mut did_add_update_path_to_src_node = false;
                        // Channels to self should not be used. This is more of belt-and-suspenders, because in
                        // practice these cases should be caught earlier:
                        // - for regular channels at channel announcement (TODO)
                        // - for first and last hops early in get_route
-                       if $src_node_id != $dest_node_id.clone() {
-                               let available_liquidity_msat = bookkept_channels_liquidity_available_msat.entry($chan_id.clone()).or_insert_with(|| {
-                                       let mut initial_liquidity_available_msat = None;
-                                       if let Some(capacity_sats) = $capacity_sats {
-                                               initial_liquidity_available_msat = Some(capacity_sats * 1000);
-                                       }
-
-                                       if let Some(htlc_maximum_msat) = $directional_info.htlc_maximum_msat {
-                                               if let Some(available_msat) = initial_liquidity_available_msat {
-                                                       initial_liquidity_available_msat = Some(cmp::min(available_msat, htlc_maximum_msat));
-                                               } else {
-                                                       initial_liquidity_available_msat = Some(htlc_maximum_msat);
-                                               }
-                                       }
-
-                                       match initial_liquidity_available_msat {
-                                               Some(available_msat) => available_msat,
-                                               // We assume channels with unknown balance have
-                                               // a capacity of 0.0025 BTC (or 250_000 sats).
-                                               None => 250_000 * 1000
-                                       }
-                               });
+                       if $src_node_id != $dest_node_id {
+                               let short_channel_id = $candidate.short_channel_id();
+                               let available_liquidity_msat = bookkept_channels_liquidity_available_msat
+                                       .entry(short_channel_id)
+                                       .or_insert_with(|| $candidate.effective_capacity().as_msat());
 
                                // It is tricky to substract $next_hops_fee_msat from available liquidity here.
                                // It may be misleading because we might later choose to reduce the value transferred
@@ -800,11 +835,10 @@ where L::Target: Logger {
                                        // Verify the liquidity offered by this channel complies to the minimal contribution.
                                        let contributes_sufficient_value = available_value_contribution_msat >= minimal_value_contribution_msat;
 
-
                                        // Do not consider candidates that exceed the maximum total cltv expiry limit.
                                        let max_total_cltv_expiry_delta = payment_params.max_total_cltv_expiry_delta;
                                        let hop_total_cltv_delta = ($next_hops_cltv_delta as u32)
-                                               .checked_add($directional_info.cltv_expiry_delta as u32)
+                                               .checked_add($candidate.cltv_expiry_delta())
                                                .unwrap_or(u32::max_value());
                                        let doesnt_exceed_cltv_delta_limit = hop_total_cltv_delta <= max_total_cltv_expiry_delta;
 
@@ -816,7 +850,7 @@ where L::Target: Logger {
                                                None => unreachable!(),
                                        };
                                        #[allow(unused_comparisons)] // $next_hops_path_htlc_minimum_msat is 0 in some calls so rustc complains
-                                       let over_path_minimum_msat = amount_to_transfer_over_msat >= $directional_info.htlc_minimum_msat &&
+                                       let over_path_minimum_msat = amount_to_transfer_over_msat >= $candidate.htlc_minimum_msat() &&
                                                amount_to_transfer_over_msat >= $next_hops_path_htlc_minimum_msat;
 
                                        // If HTLC minimum is larger than the amount we're going to transfer, we shouldn't
@@ -831,16 +865,16 @@ where L::Target: Logger {
                                                // might violate htlc_minimum_msat on the hops which are next along the
                                                // payment path (upstream to the payee). To avoid that, we recompute
                                                // path fees knowing the final path contribution after constructing it.
-                                               let path_htlc_minimum_msat = compute_fees($next_hops_path_htlc_minimum_msat, $directional_info.fees)
+                                               let path_htlc_minimum_msat = compute_fees($next_hops_path_htlc_minimum_msat, $candidate.fees())
                                                        .and_then(|fee_msat| fee_msat.checked_add($next_hops_path_htlc_minimum_msat))
-                                                       .map(|fee_msat| cmp::max(fee_msat, $directional_info.htlc_minimum_msat))
+                                                       .map(|fee_msat| cmp::max(fee_msat, $candidate.htlc_minimum_msat()))
                                                        .unwrap_or_else(|| u64::max_value());
                                                let hm_entry = dist.entry($src_node_id);
                                                let old_entry = hm_entry.or_insert_with(|| {
-                                                       // If there was previously no known way to access
-                                                       // the source node (recall it goes payee-to-payer) of $chan_id, first add
-                                                       // semi-dummy record just to compute the fees to reach the source node.
-                                                       // This will affect our decision on selecting $chan_id
+                                                       // If there was previously no known way to access the source node
+                                                       // (recall it goes payee-to-payer) of short_channel_id, first add a
+                                                       // semi-dummy record just to compute the fees to reach the source node.
+                                                       // This will affect our decision on selecting short_channel_id
                                                        // as a way to reach the $dest_node_id.
                                                        let mut fee_base_msat = u32::max_value();
                                                        let mut fee_proportional_millionths = u32::max_value();
@@ -850,19 +884,15 @@ where L::Target: Logger {
                                                        }
                                                        PathBuildingHop {
                                                                node_id: $dest_node_id.clone(),
-                                                               short_channel_id: 0,
-                                                               channel_features: $chan_features,
+                                                               candidate: $candidate.clone(),
                                                                fee_msat: 0,
-                                                               cltv_expiry_delta: 0,
                                                                src_lowest_inbound_fees: RoutingFees {
                                                                        base_msat: fee_base_msat,
                                                                        proportional_millionths: fee_proportional_millionths,
                                                                },
-                                                               channel_fees: $directional_info.fees,
                                                                next_hops_fee_msat: u64::max_value(),
                                                                hop_use_fee_msat: u64::max_value(),
                                                                total_fee_msat: u64::max_value(),
-                                                               htlc_minimum_msat: $directional_info.htlc_minimum_msat,
                                                                path_htlc_minimum_msat,
                                                                path_penalty_msat: u64::max_value(),
                                                                was_processed: false,
@@ -887,7 +917,7 @@ where L::Target: Logger {
                                                        // Ignore hop_use_fee_msat for channel-from-us as we assume all channels-from-us
                                                        // will have the same effective-fee
                                                        if $src_node_id != our_node_id {
-                                                               match compute_fees(amount_to_transfer_over_msat, $directional_info.fees) {
+                                                               match compute_fees(amount_to_transfer_over_msat, $candidate.fees()) {
                                                                        // max_value means we'll always fail
                                                                        // the old_entry.total_fee_msat > total_fee_msat check
                                                                        None => total_fee_msat = u64::max_value(),
@@ -917,7 +947,7 @@ where L::Target: Logger {
                                                        }
 
                                                        let path_penalty_msat = $next_hops_path_penalty_msat.checked_add(
-                                                               scorer.channel_penalty_msat($chan_id.clone(), amount_to_transfer_over_msat, Some(*available_liquidity_msat),
+                                                               scorer.channel_penalty_msat(short_channel_id, amount_to_transfer_over_msat, *available_liquidity_msat,
                                                                        &$src_node_id, &$dest_node_id)).unwrap_or_else(|| u64::max_value());
                                                        let new_graph_node = RouteGraphNode {
                                                                node_id: $src_node_id,
@@ -929,7 +959,7 @@ where L::Target: Logger {
                                                                path_penalty_msat,
                                                        };
 
-                                                       // Update the way of reaching $src_node_id with the given $chan_id (from $dest_node_id),
+                                                       // Update the way of reaching $src_node_id with the given short_channel_id (from $dest_node_id),
                                                        // if this way is cheaper than the already known
                                                        // (considering the cost to "reach" this channel from the route destination,
                                                        // the cost of using this channel,
@@ -958,12 +988,8 @@ where L::Target: Logger {
                                                                old_entry.hop_use_fee_msat = hop_use_fee_msat;
                                                                old_entry.total_fee_msat = total_fee_msat;
                                                                old_entry.node_id = $dest_node_id.clone();
-                                                               old_entry.short_channel_id = $chan_id.clone();
-                                                               old_entry.channel_features = $chan_features;
+                                                               old_entry.candidate = $candidate.clone();
                                                                old_entry.fee_msat = 0; // This value will be later filled with hop_use_fee_msat of the following channel
-                                                               old_entry.cltv_expiry_delta = $directional_info.cltv_expiry_delta as u32;
-                                                               old_entry.channel_fees = $directional_info.fees;
-                                                               old_entry.htlc_minimum_msat = $directional_info.htlc_minimum_msat;
                                                                old_entry.path_htlc_minimum_msat = path_htlc_minimum_msat;
                                                                old_entry.path_penalty_msat = path_penalty_msat;
                                                                #[cfg(any(test, feature = "fuzztarget"))]
@@ -1030,8 +1056,9 @@ where L::Target: Logger {
 
                        if !skip_node {
                                if let Some(first_channels) = first_hop_targets.get(&$node_id) {
-                                       for (ref first_hop, ref features, ref outbound_capacity_msat, _) in first_channels {
-                                               add_entry!(first_hop, our_node_id, $node_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat, $next_hops_path_penalty_msat, $next_hops_cltv_delta);
+                                       for details in first_channels {
+                                               let candidate = CandidateRouteHop::FirstHop { details };
+                                               add_entry!(candidate, our_node_id, $node_id, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat, $next_hops_path_penalty_msat, $next_hops_cltv_delta);
                                        }
                                }
 
@@ -1045,21 +1072,16 @@ where L::Target: Logger {
                                        for chan_id in $node.channels.iter() {
                                                let chan = network_channels.get(chan_id).unwrap();
                                                if !chan.features.requires_unknown_bits() {
-                                                       if chan.node_one == $node_id {
-                                                               // ie $node is one, ie next hop in A* is two, via the two_to_one channel
-                                                               if first_hops.is_none() || chan.node_two != our_node_id {
-                                                                       if let Some(two_to_one) = chan.two_to_one.as_ref() {
-                                                                               if two_to_one.enabled {
-                                                                                       add_entry!(chan_id, chan.node_two, chan.node_one, two_to_one, chan.capacity_sats, &chan.features, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat, $next_hops_path_penalty_msat, $next_hops_cltv_delta);
-                                                                               }
-                                                                       }
-                                                               }
-                                                       } else {
-                                                               if first_hops.is_none() || chan.node_one != our_node_id{
-                                                                       if let Some(one_to_two) = chan.one_to_two.as_ref() {
-                                                                               if one_to_two.enabled {
-                                                                                       add_entry!(chan_id, chan.node_one, chan.node_two, one_to_two, chan.capacity_sats, &chan.features, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat, $next_hops_path_penalty_msat, $next_hops_cltv_delta);
-                                                                               }
+                                                       let (directed_channel, source) =
+                                                               chan.as_directed_to(&$node_id).expect("inconsistent NetworkGraph");
+                                                       if first_hops.is_none() || *source != our_node_id {
+                                                               if let Some(direction) = directed_channel.direction() {
+                                                                       if direction.enabled {
+                                                                               let candidate = CandidateRouteHop::PublicHop {
+                                                                                       info: directed_channel.with_update().unwrap(),
+                                                                                       short_channel_id: *chan_id,
+                                                                               };
+                                                                               add_entry!(candidate, *source, $node_id, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat, $next_hops_path_penalty_msat, $next_hops_cltv_delta);
                                                                        }
                                                                }
                                                        }
@@ -1084,9 +1106,10 @@ where L::Target: Logger {
                // If first hop is a private channel and the only way to reach the payee, this is the only
                // place where it could be added.
                if let Some(first_channels) = first_hop_targets.get(&payee_node_id) {
-                       for (ref first_hop, ref features, ref outbound_capacity_msat, _) in first_channels {
-                               let added = add_entry!(first_hop, our_node_id, payee_node_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, 0, path_value_msat, 0, 0u64, 0);
-                               log_trace!(logger, "{} direct route to payee via SCID {}", if added { "Added" } else { "Skipped" }, first_hop);
+                       for details in first_channels {
+                               let candidate = CandidateRouteHop::FirstHop { details };
+                               let added = add_entry!(candidate, our_node_id, payee_node_id, 0, path_value_msat, 0, 0u64, 0);
+                               log_trace!(logger, "{} direct route to payee via SCID {}", if added { "Added" } else { "Skipped" }, candidate.short_channel_id());
                        }
                }
 
@@ -1128,43 +1151,27 @@ where L::Target: Logger {
                                let mut aggregate_next_hops_cltv_delta: u32 = 0;
 
                                for (idx, (hop, prev_hop_id)) in hop_iter.zip(prev_hop_iter).enumerate() {
-                                       // BOLT 11 doesn't allow inclusion of features for the last hop hints, which
-                                       // really sucks, cause we're gonna need that eventually.
-                                       let hop_htlc_minimum_msat: u64 = hop.htlc_minimum_msat.unwrap_or(0);
-
-                                       let directional_info = DummyDirectionalChannelInfo {
-                                               cltv_expiry_delta: hop.cltv_expiry_delta as u32,
-                                               htlc_minimum_msat: hop_htlc_minimum_msat,
-                                               htlc_maximum_msat: hop.htlc_maximum_msat,
-                                               fees: hop.fees,
-                                       };
-
-                                       // We want a value of final_value_msat * ROUTE_CAPACITY_PROVISION_FACTOR but we
-                                       // need it to increment at each hop by the fee charged at later hops. Further,
-                                       // we need to ensure we round up when we divide to get satoshis.
-                                       let channel_cap_msat = final_value_msat
-                                               .checked_mul(ROUTE_CAPACITY_PROVISION_FACTOR).and_then(|v| v.checked_add(aggregate_next_hops_fee_msat))
-                                               .unwrap_or(u64::max_value());
-                                       let channel_cap_sat = match channel_cap_msat.checked_add(999) {
-                                               None => break, // We overflowed above, just ignore this route hint
-                                               Some(val) => Some(val / 1000),
-                                       };
-
-                                       let src_node_id = NodeId::from_pubkey(&hop.src_node_id);
-                                       let dest_node_id = NodeId::from_pubkey(&prev_hop_id);
+                                       let source = NodeId::from_pubkey(&hop.src_node_id);
+                                       let target = NodeId::from_pubkey(&prev_hop_id);
+                                       let candidate = network_channels
+                                               .get(&hop.short_channel_id)
+                                               .and_then(|channel| channel.as_directed_to(&target))
+                                               .and_then(|(channel, _)| channel.with_update())
+                                               .map(|info| CandidateRouteHop::PublicHop {
+                                                       info,
+                                                       short_channel_id: hop.short_channel_id,
+                                               })
+                                               .unwrap_or_else(|| CandidateRouteHop::PrivateHop { hint: hop });
+                                       let capacity_msat = candidate.effective_capacity().as_msat();
                                        aggregate_next_hops_path_penalty_msat = aggregate_next_hops_path_penalty_msat
-                                               .checked_add(scorer.channel_penalty_msat(hop.short_channel_id, final_value_msat, None, &src_node_id, &dest_node_id))
+                                               .checked_add(scorer.channel_penalty_msat(hop.short_channel_id, final_value_msat, capacity_msat, &source, &target))
                                                .unwrap_or_else(|| u64::max_value());
 
                                        aggregate_next_hops_cltv_delta = aggregate_next_hops_cltv_delta
                                                .checked_add(hop.cltv_expiry_delta as u32)
                                                .unwrap_or_else(|| u32::max_value());
 
-                                       // We assume that the recipient only included route hints for routes which had
-                                       // sufficient value to route `final_value_msat`. Note that in the case of "0-value"
-                                       // invoices where the invoice does not specify value this may not be the case, but
-                                       // better to include the hints than not.
-                                       if !add_entry!(hop.short_channel_id, src_node_id, dest_node_id, directional_info, channel_cap_sat, &empty_channel_features, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat, aggregate_next_hops_cltv_delta) {
+                                       if !add_entry!(candidate, source, target, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat, aggregate_next_hops_cltv_delta) {
                                                // If this hop was not used then there is no use checking the preceding hops
                                                // in the RouteHint. We can break by just searching for a direct channel between
                                                // last checked hop and first_hop_targets
@@ -1173,8 +1180,9 @@ where L::Target: Logger {
 
                                        // Searching for a direct channel between last checked hop and first_hop_targets
                                        if let Some(first_channels) = first_hop_targets.get(&NodeId::from_pubkey(&prev_hop_id)) {
-                                               for (ref first_hop, ref features, ref outbound_capacity_msat, _) in first_channels {
-                                                       add_entry!(first_hop, our_node_id , NodeId::from_pubkey(&prev_hop_id), dummy_directional_info, Some(outbound_capacity_msat / 1000), features, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat, aggregate_next_hops_cltv_delta);
+                                               for details in first_channels {
+                                                       let candidate = CandidateRouteHop::FirstHop { details };
+                                                       add_entry!(candidate, our_node_id, NodeId::from_pubkey(&prev_hop_id), aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat, aggregate_next_hops_cltv_delta);
                                                }
                                        }
 
@@ -1191,6 +1199,7 @@ where L::Target: Logger {
                                                .map_or(None, |inc| inc.checked_add(aggregate_next_hops_fee_msat));
                                        aggregate_next_hops_fee_msat = if let Some(val) = hops_fee { val } else { break; };
 
+                                       let hop_htlc_minimum_msat = candidate.htlc_minimum_msat();
                                        let hop_htlc_minimum_msat_inc = if let Some(val) = compute_fees(aggregate_next_hops_path_htlc_minimum_msat, hop.fees) { val } else { break; };
                                        let hops_path_htlc_minimum = aggregate_next_hops_path_htlc_minimum_msat
                                                .checked_add(hop_htlc_minimum_msat_inc);
@@ -1207,8 +1216,9 @@ where L::Target: Logger {
                                                // always assumes that the third argument is a node to which we have a
                                                // path.
                                                if let Some(first_channels) = first_hop_targets.get(&NodeId::from_pubkey(&hop.src_node_id)) {
-                                                       for (ref first_hop, ref features, ref outbound_capacity_msat, _) in first_channels {
-                                                               add_entry!(first_hop, our_node_id , NodeId::from_pubkey(&hop.src_node_id), dummy_directional_info, Some(outbound_capacity_msat / 1000), features, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat, aggregate_next_hops_cltv_delta);
+                                                       for details in first_channels {
+                                                               let candidate = CandidateRouteHop::FirstHop { details };
+                                                               add_entry!(candidate, our_node_id, NodeId::from_pubkey(&hop.src_node_id), aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat, aggregate_next_hops_cltv_delta);
                                                        }
                                                }
                                        }
@@ -1242,9 +1252,9 @@ where L::Target: Logger {
                                'path_walk: loop {
                                        let mut features_set = false;
                                        if let Some(first_channels) = first_hop_targets.get(&ordered_hops.last().unwrap().0.node_id) {
-                                               for (scid, _, _, ref features) in first_channels {
-                                                       if *scid == ordered_hops.last().unwrap().0.short_channel_id {
-                                                               ordered_hops.last_mut().unwrap().1 = features.clone();
+                                               for details in first_channels {
+                                                       if details.short_channel_id.unwrap() == ordered_hops.last().unwrap().0.candidate.short_channel_id() {
+                                                               ordered_hops.last_mut().unwrap().1 = details.counterparty.features.to_context();
                                                                features_set = true;
                                                                break;
                                                        }
@@ -1284,12 +1294,10 @@ where L::Target: Logger {
                                        // so that fees paid for a HTLC forwarding on the current channel are
                                        // associated with the previous channel (where they will be subtracted).
                                        ordered_hops.last_mut().unwrap().0.fee_msat = new_entry.hop_use_fee_msat;
-                                       ordered_hops.last_mut().unwrap().0.cltv_expiry_delta = new_entry.cltv_expiry_delta;
                                        ordered_hops.push((new_entry.clone(), NodeFeatures::empty()));
                                }
                                ordered_hops.last_mut().unwrap().0.fee_msat = value_contribution_msat;
                                ordered_hops.last_mut().unwrap().0.hop_use_fee_msat = 0;
-                               ordered_hops.last_mut().unwrap().0.cltv_expiry_delta = final_cltv_expiry_delta;
 
                                log_trace!(logger, "Found a path back to us from the target with {} hops contributing up to {} msat: {:?}",
                                        ordered_hops.len(), value_contribution_msat, ordered_hops);
@@ -1314,7 +1322,7 @@ where L::Target: Logger {
                                // on the same liquidity in future paths.
                                let mut prevented_redundant_path_selection = false;
                                for (payment_hop, _) in payment_path.hops.iter() {
-                                       let channel_liquidity_available_msat = bookkept_channels_liquidity_available_msat.get_mut(&payment_hop.short_channel_id).unwrap();
+                                       let channel_liquidity_available_msat = bookkept_channels_liquidity_available_msat.get_mut(&payment_hop.candidate.short_channel_id()).unwrap();
                                        let mut spent_on_hop_msat = value_contribution_msat;
                                        let next_hops_fee_msat = payment_hop.next_hops_fee_msat;
                                        spent_on_hop_msat += next_hops_fee_msat;
@@ -1329,7 +1337,7 @@ where L::Target: Logger {
                                        // If we weren't capped by hitting a liquidity limit on a channel in the path,
                                        // we'll probably end up picking the same path again on the next iteration.
                                        // Decrease the available liquidity of a hop in the middle of the path.
-                                       let victim_scid = payment_path.hops[(payment_path.hops.len() - 1) / 2].0.short_channel_id;
+                                       let victim_scid = payment_path.hops[(payment_path.hops.len() - 1) / 2].0.candidate.short_channel_id();
                                        log_trace!(logger, "Disabling channel {} for future path building iterations to avoid duplicates.", victim_scid);
                                        let victim_liquidity = bookkept_channels_liquidity_available_msat.get_mut(&victim_scid).unwrap();
                                        *victim_liquidity = 0;
@@ -1460,7 +1468,7 @@ where L::Target: Logger {
                                // Now, substract the overpaid value from the most-expensive path.
                                // TODO: this could also be optimized by also sorting by feerate_per_sat_routed,
                                // so that the sender pays less fees overall. And also htlc_minimum_msat.
-                               cur_route.sort_by_key(|path| { path.hops.iter().map(|hop| hop.0.channel_fees.proportional_millionths as u64).sum::<u64>() });
+                               cur_route.sort_by_key(|path| { path.hops.iter().map(|hop| hop.0.candidate.fees().proportional_millionths as u64).sum::<u64>() });
                                let expensive_payment_path = cur_route.first_mut().unwrap();
                                // We already dropped all the small channels above, meaning all the
                                // remaining channels are larger than remaining overpaid_value_msat.
@@ -1478,16 +1486,22 @@ where L::Target: Logger {
        drawn_routes.sort_by_key(|paths| paths.iter().map(|path| path.get_total_fee_paid_msat()).sum::<u64>());
        let mut selected_paths = Vec::<Vec<Result<RouteHop, LightningError>>>::new();
        for payment_path in drawn_routes.first().unwrap() {
-               selected_paths.push(payment_path.hops.iter().map(|(payment_hop, node_features)| {
+               let mut path = payment_path.hops.iter().map(|(payment_hop, node_features)| {
                        Ok(RouteHop {
                                pubkey: PublicKey::from_slice(payment_hop.node_id.as_slice()).map_err(|_| LightningError{err: format!("Public key {:?} is invalid", &payment_hop.node_id), action: ErrorAction::IgnoreAndLog(Level::Trace)})?,
                                node_features: node_features.clone(),
-                               short_channel_id: payment_hop.short_channel_id,
-                               channel_features: payment_hop.channel_features.clone(),
+                               short_channel_id: payment_hop.candidate.short_channel_id(),
+                               channel_features: payment_hop.candidate.features(),
                                fee_msat: payment_hop.fee_msat,
-                               cltv_expiry_delta: payment_hop.cltv_expiry_delta,
+                               cltv_expiry_delta: payment_hop.candidate.cltv_expiry_delta(),
                        })
-               }).collect());
+               }).collect::<Vec<_>>();
+               // Propagate the cltv_expiry_delta one hop backwards since the delta from the current hop is
+               // applicable for the previous hop.
+               path.iter_mut().rev().fold(final_cltv_expiry_delta, |prev_cltv_expiry_delta, hop| {
+                       core::mem::replace(&mut hop.as_mut().unwrap().cltv_expiry_delta, prev_cltv_expiry_delta)
+               });
+               selected_paths.push(path);
        }
 
        if let Some(features) = &payment_params.features {
@@ -1508,7 +1522,7 @@ where L::Target: Logger {
 
 #[cfg(test)]
 mod tests {
-       use routing::scoring::Score;
+       use routing::scoring::{ProbabilisticScorer, ProbabilisticScoringParameters, Score};
        use routing::network_graph::{NetworkGraph, NetGraphMsgHandler, NodeId};
        use routing::router::{get_route, PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees};
        use chain::transaction::OutPoint;
@@ -1983,7 +1997,7 @@ mod tests {
                let (secp_ctx, network_graph, _, _, logger) = build_graph();
                let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[2]);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
 
                // Simple route to 2 via 1
 
@@ -2014,7 +2028,7 @@ mod tests {
                let (secp_ctx, network_graph, _, _, logger) = build_graph();
                let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[2]);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
 
                // Simple route to 2 via 1
 
@@ -2033,7 +2047,7 @@ mod tests {
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[2]);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
 
                // Simple route to 2 via 1
 
@@ -2158,7 +2172,7 @@ mod tests {
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[2]).with_features(InvoiceFeatures::known());
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
 
                // A route to node#2 via two paths.
                // One path allows transferring 35-40 sats, another one also allows 35-40 sats.
@@ -2294,7 +2308,7 @@ mod tests {
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[2]);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
 
                // // Disable channels 4 and 12 by flags=2
                update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
@@ -2352,7 +2366,7 @@ mod tests {
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (_, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[2]);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
 
                // Disable nodes 1, 2, and 8 by requiring unknown feature bits
                let unknown_features = NodeFeatures::known().set_unknown_feature_required();
@@ -2393,7 +2407,7 @@ mod tests {
        fn our_chans_test() {
                let (secp_ctx, network_graph, _, _, logger) = build_graph();
                let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
 
                // Route to 1 via 2 and 3 because our channel to 1 is disabled
                let payment_params = PaymentParameters::from_node_id(nodes[0]);
@@ -2522,7 +2536,7 @@ mod tests {
        fn partial_route_hint_test() {
                let (secp_ctx, network_graph, _, _, logger) = build_graph();
                let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
 
                // Simple test across 2, 3, 5, and 4 via a last_hop channel
                // Tests the behaviour when the RouteHint contains a suboptimal hop.
@@ -2621,7 +2635,7 @@ mod tests {
                let (secp_ctx, network_graph, _, _, logger) = build_graph();
                let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[6]).with_route_hints(empty_last_hop(&nodes));
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
 
                // Test handling of an empty RouteHint passed in Invoice.
 
@@ -2703,7 +2717,7 @@ mod tests {
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (_, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[6]).with_route_hints(multi_hint_last_hops(&nodes));
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                // Test through channels 2, 3, 5, 8.
                // Test shows that multiple hop hints are considered.
 
@@ -2809,7 +2823,7 @@ mod tests {
                let (secp_ctx, network_graph, _, _, logger) = build_graph();
                let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
                let payment_params = PaymentParameters::from_node_id(nodes[6]).with_route_hints(last_hops_with_public_channel(&nodes));
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                // This test shows that public routes can be present in the invoice
                // which would be handled in the same manner.
 
@@ -2844,7 +2858,7 @@ mod tests {
                // If we have a peer in the node map, we'll use their features here since we don't have
                // a way of figuring out their features from the invoice:
                assert_eq!(route.paths[0][3].node_features.le_flags(), &id_to_feature_flags(4));
-               assert_eq!(route.paths[0][3].channel_features.le_flags(), &Vec::<u8>::new());
+               assert_eq!(route.paths[0][3].channel_features.le_flags(), &id_to_feature_flags(11));
 
                assert_eq!(route.paths[0][4].pubkey, nodes[6]);
                assert_eq!(route.paths[0][4].short_channel_id, 8);
@@ -2858,7 +2872,7 @@ mod tests {
        fn our_chans_last_hop_connect_test() {
                let (secp_ctx, network_graph, _, _, logger) = build_graph();
                let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
 
                // Simple test with outbound channel to 4 to test that last_hops and first_hops connect
                let our_chans = vec![get_channel_details(Some(42), nodes[3].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)];
@@ -2979,7 +2993,7 @@ mod tests {
                }]);
                let payment_params = PaymentParameters::from_node_id(target_node_id).with_route_hints(vec![last_hops]);
                let our_chans = vec![get_channel_details(Some(42), middle_node_id, InitFeatures::from_le_bytes(vec![0b11]), outbound_capacity_msat)];
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                get_route(&source_node_id, &payment_params, &NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash()), Some(&our_chans.iter().collect::<Vec<_>>()), route_val, 42, &test_utils::TestLogger::new(), &scorer)
        }
 
@@ -3033,7 +3047,7 @@ mod tests {
 
                let (secp_ctx, network_graph, mut net_graph_msg_handler, chain_monitor, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[2]).with_features(InvoiceFeatures::known());
 
                // We will use a simple single-path route from
@@ -3305,7 +3319,7 @@ mod tests {
                // one of the latter hops is limited.
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[3]).with_features(InvoiceFeatures::known());
 
                // Path via {node7, node2, node4} is channels {12, 13, 6, 11}.
@@ -3428,7 +3442,7 @@ mod tests {
        fn ignore_fee_first_hop_test() {
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[2]);
 
                // Path via node0 is channels {1, 3}. Limit them to 100 and 50 sats (total limit 50).
@@ -3474,7 +3488,7 @@ mod tests {
        fn simple_mpp_route_test() {
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[2]).with_features(InvoiceFeatures::known());
 
                // We need a route consisting of 3 paths:
@@ -3605,7 +3619,7 @@ mod tests {
        fn long_mpp_route_test() {
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[3]).with_features(InvoiceFeatures::known());
 
                // We need a route consisting of 3 paths:
@@ -3767,7 +3781,7 @@ mod tests {
        fn mpp_cheaper_route_test() {
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[3]).with_features(InvoiceFeatures::known());
 
                // This test checks that if we have two cheaper paths and one more expensive path,
@@ -3934,7 +3948,7 @@ mod tests {
                // if the fee is not properly accounted for, the behavior is different.
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[3]).with_features(InvoiceFeatures::known());
 
                // We need a route consisting of 2 paths:
@@ -4113,7 +4127,7 @@ mod tests {
                // This bug appeared in production in some specific channel configurations.
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(PublicKey::from_slice(&[02; 33]).unwrap()).with_features(InvoiceFeatures::known())
                        .with_route_hints(vec![RouteHint(vec![RouteHintHop {
                                src_node_id: nodes[2],
@@ -4201,7 +4215,7 @@ mod tests {
                // path finding we realize that we found more capacity than we need.
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[2]).with_features(InvoiceFeatures::known());
 
                // We need a route consisting of 3 paths:
@@ -4358,7 +4372,7 @@ mod tests {
                let network_graph = Arc::new(NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash()));
                let net_graph_msg_handler = NetGraphMsgHandler::new(Arc::clone(&network_graph), None, Arc::clone(&logger));
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[6]);
 
                add_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, &privkeys[1], ChannelFeatures::from_le_bytes(id_to_feature_flags(6)), 6);
@@ -4487,7 +4501,7 @@ mod tests {
                // we calculated fees on a higher value, resulting in us ignoring such paths.
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, _, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[2]);
 
                // We modify the graph to set the htlc_maximum of channel 2 to below the value we wish to
@@ -4549,7 +4563,7 @@ mod tests {
                // resulting in us thinking there is no possible path, even if other paths exist.
                let (secp_ctx, network_graph, net_graph_msg_handler, _, logger) = build_graph();
                let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[2]).with_features(InvoiceFeatures::known());
 
                // We modify the graph to set the htlc_minimum of channel 2 and 4 as needed - channel 2
@@ -4616,7 +4630,7 @@ mod tests {
                let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
                let logger = Arc::new(test_utils::TestLogger::new());
                let network_graph = NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash());
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let payment_params = PaymentParameters::from_node_id(nodes[0]).with_features(InvoiceFeatures::known());
 
                {
@@ -4657,7 +4671,7 @@ mod tests {
                let payment_params = PaymentParameters::from_node_id(nodes[6]).with_route_hints(last_hops(&nodes));
 
                // Without penalizing each hop 100 msats, a longer path with lower fees is chosen.
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let route = get_route(
                        &our_id, &payment_params, &network_graph, None, 100, 42,
                        Arc::clone(&logger), &scorer
@@ -4670,7 +4684,7 @@ mod tests {
 
                // Applying a 100 msat penalty to each hop results in taking channels 7 and 10 to nodes[6]
                // from nodes[2] rather than channel 6, 11, and 8, even though the longer path is cheaper.
-               let scorer = test_utils::TestScorer::with_fixed_penalty(100);
+               let scorer = test_utils::TestScorer::with_penalty(100);
                let route = get_route(
                        &our_id, &payment_params, &network_graph, None, 100, 42,
                        Arc::clone(&logger), &scorer
@@ -4691,7 +4705,7 @@ mod tests {
                fn write<W: Writer>(&self, _w: &mut W) -> Result<(), ::io::Error> { unimplemented!() }
        }
        impl Score for BadChannelScorer {
-               fn channel_penalty_msat(&self, short_channel_id: u64, _send_amt: u64, _chan_amt: Option<u64>, _source: &NodeId, _target: &NodeId) -> u64 {
+               fn channel_penalty_msat(&self, short_channel_id: u64, _send_amt: u64, _capacity_msat: u64, _source: &NodeId, _target: &NodeId) -> u64 {
                        if short_channel_id == self.short_channel_id { u64::max_value() } else { 0 }
                }
 
@@ -4709,7 +4723,7 @@ mod tests {
        }
 
        impl Score for BadNodeScorer {
-               fn channel_penalty_msat(&self, _short_channel_id: u64, _send_amt: u64, _chan_amt: Option<u64>, _source: &NodeId, target: &NodeId) -> u64 {
+               fn channel_penalty_msat(&self, _short_channel_id: u64, _send_amt: u64, _capacity_msat: u64, _source: &NodeId, target: &NodeId) -> u64 {
                        if *target == self.node_id { u64::max_value() } else { 0 }
                }
 
@@ -4724,7 +4738,7 @@ mod tests {
                let payment_params = PaymentParameters::from_node_id(nodes[6]).with_route_hints(last_hops(&nodes));
 
                // A path to nodes[6] exists when no penalties are applied to any channel.
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
                let route = get_route(
                        &our_id, &payment_params, &network_graph, None, 100, 42,
                        Arc::clone(&logger), &scorer
@@ -4836,7 +4850,7 @@ mod tests {
                let (secp_ctx, network_graph, _, _, logger) = build_graph();
                let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
 
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
+               let scorer = test_utils::TestScorer::with_penalty(0);
 
                // Make sure that generally there is at least one route available
                let feasible_max_total_cltv_delta = 1008;
@@ -4881,7 +4895,6 @@ mod tests {
                        },
                };
                let graph = NetworkGraph::read(&mut d).unwrap();
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
 
                // First, get 100 (source, destination) pairs for which route-getting actually succeeds...
                let mut seed = random_init_seed() as usize;
@@ -4894,6 +4907,8 @@ mod tests {
                                let dst = PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
                                let payment_params = PaymentParameters::from_node_id(dst);
                                let amt = seed as u64 % 200_000_000;
+                               let params = ProbabilisticScoringParameters::default();
+                               let scorer = ProbabilisticScorer::new(params, &graph);
                                if get_route(src, &payment_params, &graph, None, amt, 42, &test_utils::TestLogger::new(), &scorer).is_ok() {
                                        continue 'load_endpoints;
                                }
@@ -4912,7 +4927,6 @@ mod tests {
                        },
                };
                let graph = NetworkGraph::read(&mut d).unwrap();
-               let scorer = test_utils::TestScorer::with_fixed_penalty(0);
 
                // First, get 100 (source, destination) pairs for which route-getting actually succeeds...
                let mut seed = random_init_seed() as usize;
@@ -4925,6 +4939,8 @@ mod tests {
                                let dst = PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
                                let payment_params = PaymentParameters::from_node_id(dst).with_features(InvoiceFeatures::known());
                                let amt = seed as u64 % 200_000_000;
+                               let params = ProbabilisticScoringParameters::default();
+                               let scorer = ProbabilisticScorer::new(params, &graph);
                                if get_route(src, &payment_params, &graph, None, amt, 42, &test_utils::TestLogger::new(), &scorer).is_ok() {
                                        continue 'load_endpoints;
                                }
@@ -4968,7 +4984,7 @@ mod benches {
        use chain::transaction::OutPoint;
        use ln::channelmanager::{ChannelCounterparty, ChannelDetails};
        use ln::features::{InitFeatures, InvoiceFeatures};
-       use routing::scoring::Scorer;
+       use routing::scoring::{FixedPenaltyScorer, ProbabilisticScorer, ProbabilisticScoringParameters, Scorer};
        use util::logger::{Logger, Record};
 
        use test::Bencher;
@@ -4978,15 +4994,6 @@ mod benches {
                fn log(&self, _record: &Record) {}
        }
 
-       struct ZeroPenaltyScorer;
-       impl Score for ZeroPenaltyScorer {
-               fn channel_penalty_msat(
-                       &self, _short_channel_id: u64, _send_amt: u64, _capacity_msat: Option<u64>, _source: &NodeId, _target: &NodeId
-               ) -> u64 { 0 }
-               fn payment_path_failed(&mut self, _path: &[&RouteHop], _short_channel_id: u64) {}
-               fn payment_path_successful(&mut self, _path: &[&RouteHop]) {}
-       }
-
        fn read_network_graph() -> NetworkGraph {
                let mut d = test_utils::get_route_file().unwrap();
                NetworkGraph::read(&mut d).unwrap()
@@ -5029,14 +5036,14 @@ mod benches {
        #[bench]
        fn generate_routes_with_zero_penalty_scorer(bench: &mut Bencher) {
                let network_graph = read_network_graph();
-               let scorer = ZeroPenaltyScorer;
+               let scorer = FixedPenaltyScorer::with_penalty(0);
                generate_routes(bench, &network_graph, scorer, InvoiceFeatures::empty());
        }
 
        #[bench]
        fn generate_mpp_routes_with_zero_penalty_scorer(bench: &mut Bencher) {
                let network_graph = read_network_graph();
-               let scorer = ZeroPenaltyScorer;
+               let scorer = FixedPenaltyScorer::with_penalty(0);
                generate_routes(bench, &network_graph, scorer, InvoiceFeatures::known());
        }
 
@@ -5054,6 +5061,22 @@ mod benches {
                generate_routes(bench, &network_graph, scorer, InvoiceFeatures::known());
        }
 
+       #[bench]
+       fn generate_routes_with_probabilistic_scorer(bench: &mut Bencher) {
+               let network_graph = read_network_graph();
+               let params = ProbabilisticScoringParameters::default();
+               let scorer = ProbabilisticScorer::new(params, &network_graph);
+               generate_routes(bench, &network_graph, scorer, InvoiceFeatures::empty());
+       }
+
+       #[bench]
+       fn generate_mpp_routes_with_probabilistic_scorer(bench: &mut Bencher) {
+               let network_graph = read_network_graph();
+               let params = ProbabilisticScoringParameters::default();
+               let scorer = ProbabilisticScorer::new(params, &network_graph);
+               generate_routes(bench, &network_graph, scorer, InvoiceFeatures::known());
+       }
+
        fn generate_routes<S: Score>(
                bench: &mut Bencher, graph: &NetworkGraph, mut scorer: S, features: InvoiceFeatures
        ) {
index 20a8afcabcf827298229cb44ff9903cbc000c9f6..b02b61fa9f6c0381fe9fd7ffcad4eedd23656be5 100644 (file)
@@ -9,8 +9,8 @@
 
 //! Utilities for scoring payment channels.
 //!
-//! [`Scorer`] may be given to [`find_route`] to score payment channels during path finding when a
-//! custom [`Score`] implementation is not needed.
+//! [`ProbabilisticScorer`] may be given to [`find_route`] to score payment channels during path
+//! finding when a custom [`Score`] implementation is not needed.
 //!
 //! # Example
 //!
@@ -19,7 +19,7 @@
 //! #
 //! # use lightning::routing::network_graph::NetworkGraph;
 //! # use lightning::routing::router::{RouteParameters, find_route};
-//! # use lightning::routing::scoring::{Scorer, ScoringParameters};
+//! # use lightning::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringParameters, Scorer, ScoringParameters};
 //! # use lightning::util::logger::{Logger, Record};
 //! # use secp256k1::key::PublicKey;
 //! #
 //! # impl Logger for FakeLogger {
 //! #     fn log(&self, record: &Record) { unimplemented!() }
 //! # }
-//! # fn find_scored_route(payer: PublicKey, params: RouteParameters, network_graph: NetworkGraph) {
+//! # fn find_scored_route(payer: PublicKey, route_params: RouteParameters, network_graph: NetworkGraph) {
 //! # let logger = FakeLogger {};
 //! #
 //! // Use the default channel penalties.
-//! let scorer = Scorer::default();
+//! let params = ProbabilisticScoringParameters::default();
+//! let scorer = ProbabilisticScorer::new(params, &network_graph);
 //!
 //! // Or use custom channel penalties.
-//! let scorer = Scorer::new(ScoringParameters {
-//!     base_penalty_msat: 1000,
-//!     failure_penalty_msat: 2 * 1024 * 1000,
-//!     ..ScoringParameters::default()
-//! });
+//! let params = ProbabilisticScoringParameters {
+//!     liquidity_penalty_multiplier_msat: 2 * 1000,
+//!     ..ProbabilisticScoringParameters::default()
+//! };
+//! let scorer = ProbabilisticScorer::new(params, &network_graph);
 //!
-//! let route = find_route(&payer, &params, &network_graph, None, &logger, &scorer);
+//! let route = find_route(&payer, &route_params, &network_graph, None, &logger, &scorer);
 //! # }
 //! ```
 //!
 //! [`find_route`]: crate::routing::router::find_route
 
 use ln::msgs::DecodeError;
-use routing::network_graph::NodeId;
+use routing::network_graph::{NetworkGraph, NodeId};
 use routing::router::RouteHop;
-use util::ser::{Readable, Writeable, Writer};
+use util::ser::{Readable, ReadableArgs, Writeable, Writer};
 
 use prelude::*;
 use core::cell::{RefCell, RefMut};
-use core::ops::DerefMut;
+use core::ops::{Deref, DerefMut};
 use core::time::Duration;
 use io::{self, Read};
 use sync::{Mutex, MutexGuard};
@@ -82,16 +83,12 @@ pub trait Score $(: $supertrait)* {
        /// Returns the fee in msats willing to be paid to avoid routing `send_amt_msat` through the
        /// given channel in the direction from `source` to `target`.
        ///
-       /// The channel's capacity (less any other MPP parts which are also being considered for use in
-       /// the same payment) is given by `channel_capacity_msat`. It may be guessed from various
-       /// sources or assumed from no data at all.
-       ///
-       /// For hints provided in the invoice, we assume the channel has sufficient capacity to accept
-       /// the invoice's full amount, and provide a `channel_capacity_msat` of `None`. In all other
-       /// cases it is set to `Some`, even if we're guessing at the channel value.
-       ///
-       /// Your code should be overflow-safe through a `channel_capacity_msat` of 21 million BTC.
-       fn channel_penalty_msat(&self, short_channel_id: u64, send_amt_msat: u64, channel_capacity_msat: Option<u64>, source: &NodeId, target: &NodeId) -> u64;
+       /// The channel's capacity (less any other MPP parts that are also being considered for use in
+       /// the same payment) is given by `capacity_msat`. It may be determined from various sources
+       /// such as a chain data, network gossip, or invoice hints. For invoice hints, a capacity near
+       /// [`u64::max_value`] is given to indicate sufficient capacity for the invoice's full amount.
+       /// Thus, implementations should be overflow-safe.
+       fn channel_penalty_msat(&self, short_channel_id: u64, send_amt_msat: u64, capacity_msat: u64, source: &NodeId, target: &NodeId) -> u64;
 
        /// Handles updating channel penalties after failing to route through a channel.
        fn payment_path_failed(&mut self, path: &[&RouteHop], short_channel_id: u64);
@@ -101,8 +98,8 @@ pub trait Score $(: $supertrait)* {
 }
 
 impl<S: Score, T: DerefMut<Target=S> $(+ $supertrait)*> Score for T {
-       fn channel_penalty_msat(&self, short_channel_id: u64, send_amt_msat: u64, channel_capacity_msat: Option<u64>, source: &NodeId, target: &NodeId) -> u64 {
-               self.deref().channel_penalty_msat(short_channel_id, send_amt_msat, channel_capacity_msat, source, target)
+       fn channel_penalty_msat(&self, short_channel_id: u64, send_amt_msat: u64, capacity_msat: u64, source: &NodeId, target: &NodeId) -> u64 {
+               self.deref().channel_penalty_msat(short_channel_id, send_amt_msat, capacity_msat, source, target)
        }
 
        fn payment_path_failed(&mut self, path: &[&RouteHop], short_channel_id: u64) {
@@ -192,26 +189,55 @@ impl<'a, S: Writeable> Writeable for MutexGuard<'a, S> {
        }
 }
 
+/// [`Score`] implementation that uses a fixed penalty.
+pub struct FixedPenaltyScorer {
+       penalty_msat: u64,
+}
+
+impl_writeable_tlv_based!(FixedPenaltyScorer, {
+       (0, penalty_msat, required),
+});
+
+impl FixedPenaltyScorer {
+       /// Creates a new scorer using `penalty_msat`.
+       pub fn with_penalty(penalty_msat: u64) -> Self {
+               Self { penalty_msat }
+       }
+}
+
+impl Score for FixedPenaltyScorer {
+       fn channel_penalty_msat(&self, _: u64, _: u64, _: u64, _: &NodeId, _: &NodeId) -> u64 {
+               self.penalty_msat
+       }
+
+       fn payment_path_failed(&mut self, _path: &[&RouteHop], _short_channel_id: u64) {}
+
+       fn payment_path_successful(&mut self, _path: &[&RouteHop]) {}
+}
+
 /// [`Score`] implementation that provides reasonable default behavior.
 ///
 /// 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.
 ///
-/// See [module-level documentation] for usage.
-///
-/// [module-level documentation]: crate::routing::scoring
-#[cfg(not(feature = "no-std"))]
-pub type Scorer = ScorerUsingTime::<std::time::Instant>;
-/// [`Score`] implementation that provides reasonable default behavior.
+/// See [module-level documentation] for usage and [`ScoringParameters`] for customization.
 ///
-/// 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.
+/// # Note
 ///
-/// See [module-level documentation] for usage and [`ScoringParameters`] for customization.
+/// 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")]
-pub type Scorer = ScorerUsingTime::<time::Eternity>;
+type ConfiguredTime = time::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
@@ -219,14 +245,8 @@ pub type Scorer = ScorerUsingTime::<time::Eternity>;
 
 /// [`Score`] implementation.
 ///
-/// See [`Scorer`] for details.
-///
-/// # Note
-///
-/// Mixing the `no-std` feature between serialization and deserialization results in undefined
-/// behavior.
-///
 /// (C-not exported) generally all users should use the [`Scorer`] type alias.
+#[doc(hidden)]
 pub struct ScorerUsingTime<T: Time> {
        params: ScoringParameters,
        // TODO: Remove entries of closed channels.
@@ -272,6 +292,8 @@ pub struct ScoringParameters {
        ///
        /// 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
@@ -309,18 +331,6 @@ impl<T: Time> ScorerUsingTime<T> {
                        channel_failures: HashMap::new(),
                }
        }
-
-       /// Creates a new scorer using `penalty_msat` as a fixed channel penalty.
-       #[cfg(any(test, feature = "fuzztarget", feature = "_test_utils"))]
-       pub fn with_fixed_penalty(penalty_msat: u64) -> Self {
-               Self::new(ScoringParameters {
-                       base_penalty_msat: penalty_msat,
-                       failure_penalty_msat: 0,
-                       failure_penalty_half_life: Duration::from_secs(0),
-                       overuse_penalty_start_1024th: 1024,
-                       overuse_penalty_msat_per_1024th: 0,
-               })
-       }
 }
 
 impl<T: Time> ChannelFailure<T> {
@@ -369,23 +379,19 @@ impl Default for ScoringParameters {
 
 impl<T: Time> Score for ScorerUsingTime<T> {
        fn channel_penalty_msat(
-               &self, short_channel_id: u64, send_amt_msat: u64, chan_capacity_opt: Option<u64>, _source: &NodeId, _target: &NodeId
+               &self, short_channel_id: u64, send_amt_msat: u64, capacity_msat: u64, _source: &NodeId, _target: &NodeId
        ) -> 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;
-
-               if let Some(chan_capacity_msat) = chan_capacity_opt {
-                       let send_1024ths = send_amt_msat.checked_mul(1024).unwrap_or(u64::max_value()) / chan_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());
-                       }
+               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
@@ -460,17 +466,418 @@ impl<T: Time> Readable for ChannelFailure<T> {
        }
 }
 
+/// [`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.
+///
+/// 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.
+///
+/// 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.
+///
+/// [1]: https://arxiv.org/abs/2107.05322
+pub type ProbabilisticScorer<G> = ProbabilisticScorerUsingTime::<G, ConfiguredTime>;
+
+/// Probabilistic [`Score`] implementation.
+///
+/// (C-not exported) generally all users should use the [`ProbabilisticScorer`] type alias.
+#[doc(hidden)]
+pub struct ProbabilisticScorerUsingTime<G: Deref<Target = NetworkGraph>, T: Time> {
+       params: ProbabilisticScoringParameters,
+       network_graph: G,
+       // TODO: Remove entries of closed channels.
+       channel_liquidities: HashMap<u64, ChannelLiquidity<T>>,
+}
+
+/// Parameters for configuring [`ProbabilisticScorer`].
+#[derive(Clone, Copy)]
+pub struct ProbabilisticScoringParameters {
+       /// A multiplier used to determine the amount in msats willing to be paid to avoid routing
+       /// through a channel, as per multiplying by the negative `log10` of the channel's success
+       /// probability for a payment.
+       ///
+       /// The success probability is determined by the effective channel capacity, the payment amount,
+       /// and knowledge learned from prior successful and unsuccessful payments. The lower bound of
+       /// the success probability is 0.01, effectively limiting the penalty to the range
+       /// `0..=2*liquidity_penalty_multiplier_msat`. The knowledge learned is decayed over time based
+       /// on [`liquidity_offset_half_life`].
+       ///
+       /// Default value: 10,000 msat
+       ///
+       /// [`liquidity_offset_half_life`]: Self::liquidity_offset_half_life
+       pub liquidity_penalty_multiplier_msat: u64,
+
+       /// The time required to elapse before any knowledge learned about channel liquidity balances is
+       /// cut in half.
+       ///
+       /// The bounds are defined in terms of offsets and are initially zero. Increasing the offsets
+       /// gives tighter bounds on the channel liquidity balance. Thus, halving the offsets decreases
+       /// the certainty of the channel liquidity balance.
+       ///
+       /// Default value: 1 hour
+       ///
+       /// # Note
+       ///
+       /// When built with the `no-std` feature, time will never elapse. Therefore, the channel
+       /// liquidity knowledge will never decay except when the bounds cross.
+       pub liquidity_offset_half_life: Duration,
+}
+
+impl_writeable_tlv_based!(ProbabilisticScoringParameters, {
+       (0, liquidity_penalty_multiplier_msat, required),
+       (2, liquidity_offset_half_life, required),
+});
+
+/// Accounting for channel liquidity balance uncertainty.
+///
+/// Direction is defined in terms of [`NodeId`] partial ordering, where the source node is the
+/// first node in the ordering of the channel's counterparties. Thus, swapping the two liquidity
+/// offset fields gives the opposite direction.
+struct ChannelLiquidity<T: Time> {
+       /// Lower channel liquidity bound in terms of an offset from zero.
+       min_liquidity_offset_msat: u64,
+
+       /// Upper channel liquidity bound in terms of an offset from the effective capacity.
+       max_liquidity_offset_msat: u64,
+
+       /// Time when the liquidity bounds were last modified.
+       last_updated: T,
+}
+
+/// A snapshot of [`ChannelLiquidity`] in one direction assuming a certain channel capacity and
+/// decayed with a given half life.
+struct DirectedChannelLiquidity<L: Deref<Target = u64>, T: Time, U: Deref<Target = T>> {
+       min_liquidity_offset_msat: L,
+       max_liquidity_offset_msat: L,
+       capacity_msat: u64,
+       last_updated: U,
+       now: T,
+       half_life: Duration,
+}
+
+impl<G: Deref<Target = NetworkGraph>, T: Time> ProbabilisticScorerUsingTime<G, T> {
+       /// 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) -> Self {
+               Self {
+                       params,
+                       network_graph,
+                       channel_liquidities: HashMap::new(),
+               }
+       }
+
+       #[cfg(test)]
+       fn with_channel(mut self, short_channel_id: u64, liquidity: ChannelLiquidity<T>) -> Self {
+               assert!(self.channel_liquidities.insert(short_channel_id, liquidity).is_none());
+               self
+       }
+}
+
+impl Default for ProbabilisticScoringParameters {
+       fn default() -> Self {
+               Self {
+                       liquidity_penalty_multiplier_msat: 10_000,
+                       liquidity_offset_half_life: Duration::from_secs(3600),
+               }
+       }
+}
+
+impl<T: Time> ChannelLiquidity<T> {
+       #[inline]
+       fn new() -> Self {
+               Self {
+                       min_liquidity_offset_msat: 0,
+                       max_liquidity_offset_msat: 0,
+                       last_updated: T::now(),
+               }
+       }
+
+       /// Returns a view of the channel liquidity directed from `source` to `target` assuming
+       /// `capacity_msat`.
+       fn as_directed(
+               &self, source: &NodeId, target: &NodeId, capacity_msat: u64, half_life: Duration
+       ) -> DirectedChannelLiquidity<&u64, T, &T> {
+               let (min_liquidity_offset_msat, max_liquidity_offset_msat) = if source < target {
+                       (&self.min_liquidity_offset_msat, &self.max_liquidity_offset_msat)
+               } else {
+                       (&self.max_liquidity_offset_msat, &self.min_liquidity_offset_msat)
+               };
+
+               DirectedChannelLiquidity {
+                       min_liquidity_offset_msat,
+                       max_liquidity_offset_msat,
+                       capacity_msat,
+                       last_updated: &self.last_updated,
+                       now: T::now(),
+                       half_life,
+               }
+       }
+
+       /// Returns a mutable view of the channel liquidity directed from `source` to `target` assuming
+       /// `capacity_msat`.
+       fn as_directed_mut(
+               &mut self, source: &NodeId, target: &NodeId, capacity_msat: u64, half_life: Duration
+       ) -> DirectedChannelLiquidity<&mut u64, T, &mut T> {
+               let (min_liquidity_offset_msat, max_liquidity_offset_msat) = if source < target {
+                       (&mut self.min_liquidity_offset_msat, &mut self.max_liquidity_offset_msat)
+               } else {
+                       (&mut self.max_liquidity_offset_msat, &mut self.min_liquidity_offset_msat)
+               };
+
+               DirectedChannelLiquidity {
+                       min_liquidity_offset_msat,
+                       max_liquidity_offset_msat,
+                       capacity_msat,
+                       last_updated: &mut self.last_updated,
+                       now: T::now(),
+                       half_life,
+               }
+       }
+}
+
+impl<L: Deref<Target = u64>, T: Time, U: Deref<Target = T>> DirectedChannelLiquidity<L, T, U> {
+       /// Returns the success probability of routing the given HTLC `amount_msat` through the channel
+       /// in this direction.
+       fn success_probability(&self, amount_msat: u64) -> f64 {
+               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 > max_liquidity_msat {
+                       0.0
+               } else if amount_msat <= min_liquidity_msat {
+                       1.0
+               } else {
+                       let numerator = max_liquidity_msat + 1 - amount_msat;
+                       let denominator = max_liquidity_msat + 1 - min_liquidity_msat;
+                       numerator as f64 / denominator as f64
+               }.max(0.01) // Lower bound the success probability to ensure some channel is selected.
+       }
+
+       /// Returns the lower bound of the channel liquidity balance in this direction.
+       fn min_liquidity_msat(&self) -> u64 {
+               self.decayed_offset_msat(*self.min_liquidity_offset_msat)
+       }
+
+       /// Returns the upper bound of the channel liquidity balance in this direction.
+       fn max_liquidity_msat(&self) -> u64 {
+               self.capacity_msat
+                       .checked_sub(self.decayed_offset_msat(*self.max_liquidity_offset_msat))
+                       .unwrap_or(0)
+       }
+
+       fn decayed_offset_msat(&self, offset_msat: u64) -> u64 {
+               self.now.duration_since(*self.last_updated).as_secs()
+                       .checked_div(self.half_life.as_secs())
+                       .and_then(|decays| offset_msat.checked_shr(decays as u32))
+                       .unwrap_or(0)
+       }
+}
+
+impl<L: DerefMut<Target = u64>, T: Time, U: DerefMut<Target = T>> DirectedChannelLiquidity<L, T, U> {
+       /// Adjusts the channel liquidity balance bounds when failing to route `amount_msat`.
+       fn failed_at_channel(&mut self, amount_msat: u64) {
+               if amount_msat < self.max_liquidity_msat() {
+                       self.set_max_liquidity_msat(amount_msat);
+               }
+       }
+
+       /// Adjusts the channel liquidity balance bounds when failing to route `amount_msat` downstream.
+       fn failed_downstream(&mut self, amount_msat: u64) {
+               if amount_msat > self.min_liquidity_msat() {
+                       self.set_min_liquidity_msat(amount_msat);
+               }
+       }
+
+       /// Adjusts the channel liquidity balance bounds when successfully routing `amount_msat`.
+       fn successful(&mut self, amount_msat: u64) {
+               let max_liquidity_msat = self.max_liquidity_msat().checked_sub(amount_msat).unwrap_or(0);
+               self.set_max_liquidity_msat(max_liquidity_msat);
+       }
+
+       /// Adjusts the lower bound of the channel liquidity balance in this direction.
+       fn set_min_liquidity_msat(&mut self, amount_msat: u64) {
+               *self.min_liquidity_offset_msat = amount_msat;
+               *self.max_liquidity_offset_msat = if amount_msat > self.max_liquidity_msat() {
+                       0
+               } else {
+                       self.decayed_offset_msat(*self.max_liquidity_offset_msat)
+               };
+               *self.last_updated = self.now;
+       }
+
+       /// Adjusts the upper bound of the channel liquidity balance in this direction.
+       fn set_max_liquidity_msat(&mut self, amount_msat: u64) {
+               *self.max_liquidity_offset_msat = self.capacity_msat.checked_sub(amount_msat).unwrap_or(0);
+               *self.min_liquidity_offset_msat = if amount_msat < self.min_liquidity_msat() {
+                       0
+               } else {
+                       self.decayed_offset_msat(*self.min_liquidity_offset_msat)
+               };
+               *self.last_updated = self.now;
+       }
+}
+
+impl<G: Deref<Target = NetworkGraph>, T: Time> Score for ProbabilisticScorerUsingTime<G, T> {
+       fn channel_penalty_msat(
+               &self, short_channel_id: u64, amount_msat: u64, capacity_msat: u64, source: &NodeId,
+               target: &NodeId
+       ) -> u64 {
+               let liquidity_penalty_multiplier_msat = self.params.liquidity_penalty_multiplier_msat;
+               let liquidity_offset_half_life = self.params.liquidity_offset_half_life;
+               let success_probability = self.channel_liquidities
+                       .get(&short_channel_id)
+                       .unwrap_or(&ChannelLiquidity::new())
+                       .as_directed(source, target, capacity_msat, liquidity_offset_half_life)
+                       .success_probability(amount_msat);
+               // NOTE: If success_probability is ever changed to return 0.0, log10 is undefined so return
+               // u64::max_value instead.
+               debug_assert!(success_probability > core::f64::EPSILON);
+               (-(success_probability.log10()) * liquidity_penalty_multiplier_msat as f64) as u64
+       }
+
+       fn payment_path_failed(&mut self, path: &[&RouteHop], short_channel_id: u64) {
+               let amount_msat = path.split_last().map(|(hop, _)| hop.fee_msat).unwrap_or(0);
+               let liquidity_offset_half_life = self.params.liquidity_offset_half_life;
+               let network_graph = self.network_graph.read_only();
+               for hop in path {
+                       let target = NodeId::from_pubkey(&hop.pubkey);
+                       let channel_directed_from_source = network_graph.channels()
+                               .get(&hop.short_channel_id)
+                               .and_then(|channel| channel.as_directed_to(&target));
+
+                       // Only score announced channels.
+                       if let Some((channel, source)) = channel_directed_from_source {
+                               let capacity_msat = channel.effective_capacity().as_msat();
+                               if hop.short_channel_id == short_channel_id {
+                                       self.channel_liquidities
+                                               .entry(hop.short_channel_id)
+                                               .or_insert_with(ChannelLiquidity::new)
+                                               .as_directed_mut(source, &target, capacity_msat, liquidity_offset_half_life)
+                                               .failed_at_channel(amount_msat);
+                                       break;
+                               }
+
+                               self.channel_liquidities
+                                       .entry(hop.short_channel_id)
+                                       .or_insert_with(ChannelLiquidity::new)
+                                       .as_directed_mut(source, &target, capacity_msat, liquidity_offset_half_life)
+                                       .failed_downstream(amount_msat);
+                       }
+               }
+       }
+
+       fn payment_path_successful(&mut self, path: &[&RouteHop]) {
+               let amount_msat = path.split_last().map(|(hop, _)| hop.fee_msat).unwrap_or(0);
+               let liquidity_offset_half_life = self.params.liquidity_offset_half_life;
+               let network_graph = self.network_graph.read_only();
+               for hop in path {
+                       let target = NodeId::from_pubkey(&hop.pubkey);
+                       let channel_directed_from_source = network_graph.channels()
+                               .get(&hop.short_channel_id)
+                               .and_then(|channel| channel.as_directed_to(&target));
+
+                       // Only score announced channels.
+                       if let Some((channel, source)) = channel_directed_from_source {
+                               let capacity_msat = channel.effective_capacity().as_msat();
+                               self.channel_liquidities
+                                       .entry(hop.short_channel_id)
+                                       .or_insert_with(ChannelLiquidity::new)
+                                       .as_directed_mut(source, &target, capacity_msat, liquidity_offset_half_life)
+                                       .successful(amount_msat);
+                       }
+               }
+       }
+}
+
+impl<G: Deref<Target = NetworkGraph>, T: Time> Writeable for ProbabilisticScorerUsingTime<G, T> {
+       #[inline]
+       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+               write_tlv_fields!(w, {
+                       (0, self.channel_liquidities, required)
+               });
+               Ok(())
+       }
+}
+
+impl<G, T> ReadableArgs<(ProbabilisticScoringParameters, G)> for ProbabilisticScorerUsingTime<G, T>
+where
+       G: Deref<Target = NetworkGraph>,
+       T: Time,
+{
+       #[inline]
+       fn read<R: Read>(
+               r: &mut R, args: (ProbabilisticScoringParameters, G)
+       ) -> Result<Self, DecodeError> {
+               let (params, network_graph) = args;
+               let mut channel_liquidities = HashMap::new();
+               read_tlv_fields!(r, {
+                       (0, channel_liquidities, required)
+               });
+               Ok(Self {
+                       params,
+                       network_graph,
+                       channel_liquidities,
+               })
+       }
+}
+
+impl<T: Time> Writeable for ChannelLiquidity<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.min_liquidity_offset_msat, required),
+                       (2, self.max_liquidity_offset_msat, required),
+                       (4, duration_since_epoch, required),
+               });
+               Ok(())
+       }
+}
+
+impl<T: Time> Readable for ChannelLiquidity<T> {
+       #[inline]
+       fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
+               let mut min_liquidity_offset_msat = 0;
+               let mut max_liquidity_offset_msat = 0;
+               let mut duration_since_epoch = Duration::from_secs(0);
+               read_tlv_fields!(r, {
+                       (0, min_liquidity_offset_msat, required),
+                       (2, max_liquidity_offset_msat, required),
+                       (4, duration_since_epoch, required),
+               });
+               Ok(Self {
+                       min_liquidity_offset_msat,
+                       max_liquidity_offset_msat,
+                       last_updated: T::now() - (T::duration_since_epoch() - duration_since_epoch),
+               })
+       }
+}
+
 pub(crate) mod time {
        use core::ops::Sub;
        use core::time::Duration;
        /// A measurement of time.
-       pub trait Time: Sub<Duration, Output = Self> where Self: Sized {
+       pub trait Time: Copy + Sub<Duration, Output = Self> where Self: Sized {
                /// Returns an instance corresponding to the current moment.
                fn now() -> Self;
 
                /// Returns the amount of time elapsed since `self` was created.
                fn elapsed(&self) -> Duration;
 
+               /// Returns the amount of time passed between `earlier` and `self`.
+               fn duration_since(&self, earlier: Self) -> Duration;
+
                /// Returns the amount of time passed since the beginning of [`Time`].
                ///
                /// Used during (de-)serialization.
@@ -478,7 +885,7 @@ pub(crate) mod time {
        }
 
        /// A state in which time has no meaning.
-       #[derive(Debug, PartialEq, Eq)]
+       #[derive(Clone, Copy, Debug, PartialEq, Eq)]
        pub struct Eternity;
 
        #[cfg(not(feature = "no-std"))]
@@ -487,6 +894,10 @@ pub(crate) mod time {
                        std::time::Instant::now()
                }
 
+               fn duration_since(&self, earlier: Self) -> Duration {
+                       self.duration_since(earlier)
+               }
+
                fn duration_since_epoch() -> Duration {
                        use std::time::SystemTime;
                        SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap()
@@ -502,6 +913,10 @@ pub(crate) mod time {
                        Self
                }
 
+               fn duration_since(&self, _earlier: Self) -> Duration {
+                       Duration::from_secs(0)
+               }
+
                fn duration_since_epoch() -> Duration {
                        Duration::from_secs(0)
                }
@@ -524,23 +939,30 @@ pub(crate) use self::time::Time;
 
 #[cfg(test)]
 mod tests {
-       use super::{ScoringParameters, ScorerUsingTime, Time};
+       use super::{ChannelLiquidity, ProbabilisticScoringParameters, ProbabilisticScorerUsingTime, ScoringParameters, ScorerUsingTime, Time};
        use super::time::Eternity;
 
        use ln::features::{ChannelFeatures, NodeFeatures};
+       use ln::msgs::{ChannelAnnouncement, ChannelUpdate, OptionalField, UnsignedChannelAnnouncement, UnsignedChannelUpdate};
        use routing::scoring::Score;
-       use routing::network_graph::NodeId;
+       use routing::network_graph::{NetworkGraph, NodeId};
        use routing::router::RouteHop;
-       use util::ser::{Readable, Writeable};
+       use util::ser::{Readable, ReadableArgs, Writeable};
 
-       use bitcoin::secp256k1::PublicKey;
+       use bitcoin::blockdata::constants::genesis_block;
+       use bitcoin::hashes::Hash;
+       use bitcoin::hashes::sha256d::Hash as Sha256dHash;
+       use bitcoin::network::constants::Network;
+       use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
        use core::cell::Cell;
        use core::ops::Sub;
        use core::time::Duration;
        use io;
 
+       // `Time` tests
+
        /// Time that can be advanced manually in tests.
-       #[derive(Debug, PartialEq, Eq)]
+       #[derive(Clone, Copy, Debug, PartialEq, Eq)]
        struct SinceEpoch(Duration);
 
        impl SinceEpoch {
@@ -558,6 +980,10 @@ mod tests {
                        Self(Self::duration_since_epoch())
                }
 
+               fn duration_since(&self, earlier: Self) -> Duration {
+                       self.0 - earlier.0
+               }
+
                fn duration_since_epoch() -> Duration {
                        Self::ELAPSED.with(|elapsed| elapsed.get())
                }
@@ -600,15 +1026,35 @@ mod tests {
                assert_eq!(later - elapsed, now);
        }
 
+       // `Scorer` tests
+
        /// 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()
+       }
+
+       fn target_privkey() -> SecretKey {
+               SecretKey::from_slice(&[43; 32]).unwrap()
+       }
+
+       fn source_pubkey() -> PublicKey {
+               let secp_ctx = Secp256k1::new();
+               PublicKey::from_secret_key(&secp_ctx, &source_privkey())
+       }
+
+       fn target_pubkey() -> PublicKey {
+               let secp_ctx = Secp256k1::new();
+               PublicKey::from_secret_key(&secp_ctx, &target_privkey())
+       }
+
        fn source_node_id() -> NodeId {
-               NodeId::from_pubkey(&PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap())
+               NodeId::from_pubkey(&source_pubkey())
        }
 
        fn target_node_id() -> NodeId {
-               NodeId::from_pubkey(&PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap())
+               NodeId::from_pubkey(&target_pubkey())
        }
 
        #[test]
@@ -622,10 +1068,10 @@ mod tests {
                });
                let source = source_node_id();
                let target = target_node_id();
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_000);
 
                SinceEpoch::advance(Duration::from_secs(1));
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_000);
        }
 
        #[test]
@@ -639,16 +1085,16 @@ mod tests {
                });
                let source = source_node_id();
                let target = target_node_id();
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_000);
 
                scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_064);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_064);
 
                scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_128);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_128);
 
                scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_192);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_192);
        }
 
        #[test]
@@ -662,25 +1108,25 @@ mod tests {
                });
                let source = source_node_id();
                let target = target_node_id();
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_000);
 
                scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_512);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_512);
 
                SinceEpoch::advance(Duration::from_secs(9));
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_512);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_512);
 
                SinceEpoch::advance(Duration::from_secs(1));
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_256);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_256);
 
                SinceEpoch::advance(Duration::from_secs(10 * 8));
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_001);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_001);
 
                SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_000);
 
                SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_000);
        }
 
        #[test]
@@ -694,18 +1140,18 @@ mod tests {
                });
                let source = source_node_id();
                let target = target_node_id();
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_000);
 
                scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_512);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 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, 1, Some(1), &source, &target), 1_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_000);
 
                SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_000);
        }
 
        #[test]
@@ -719,19 +1165,19 @@ mod tests {
                });
                let source = source_node_id();
                let target = target_node_id();
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_000);
 
                scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_512);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_512);
 
                SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_256);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_256);
 
                scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_768);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_768);
 
                SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_384);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_384);
        }
 
        #[test]
@@ -745,13 +1191,13 @@ mod tests {
                });
                let source = source_node_id();
                let target = target_node_id();
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_000);
 
                scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_512);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_512);
 
                SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_256);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_256);
 
                let hop = RouteHop {
                        pubkey: PublicKey::from_slice(target.as_slice()).unwrap(),
@@ -762,10 +1208,10 @@ mod tests {
                        cltv_expiry_delta: 18,
                };
                scorer.payment_path_successful(&[&hop]);
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_128);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_128);
 
                SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_064);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_064);
        }
 
        #[test]
@@ -781,20 +1227,20 @@ mod tests {
                let target = target_node_id();
 
                scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_512);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_512);
 
                SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_256);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_256);
 
                scorer.payment_path_failed(&[], 43);
-               assert_eq!(scorer.channel_penalty_msat(43, 1, Some(1), &source, &target), 1_512);
+               assert_eq!(scorer.channel_penalty_msat(43, 1, 1, &source, &target), 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, 1, Some(1), &source, &target), 1_256);
-               assert_eq!(deserialized_scorer.channel_penalty_msat(43, 1, Some(1), &source, &target), 1_512);
+               assert_eq!(deserialized_scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_256);
+               assert_eq!(deserialized_scorer.channel_penalty_msat(43, 1, 1, &source, &target), 1_512);
        }
 
        #[test]
@@ -810,7 +1256,7 @@ mod tests {
                let target = target_node_id();
 
                scorer.payment_path_failed(&[], 42);
-               assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_512);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_512);
 
                let mut serialized_scorer = Vec::new();
                scorer.write(&mut serialized_scorer).unwrap();
@@ -818,10 +1264,10 @@ mod tests {
                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, 1, Some(1), &source, &target), 1_256);
+               assert_eq!(deserialized_scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_256);
 
                SinceEpoch::advance(Duration::from_secs(10));
-               assert_eq!(deserialized_scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_128);
+               assert_eq!(deserialized_scorer.channel_penalty_msat(42, 1, 1, &source, &target), 1_128);
        }
 
        #[test]
@@ -836,11 +1282,631 @@ mod tests {
                let source = source_node_id();
                let target = target_node_id();
 
-               assert_eq!(scorer.channel_penalty_msat(42, 1_000, None, &source, &target), 0);
-               assert_eq!(scorer.channel_penalty_msat(42, 1_000, Some(1_024_000), &source, &target), 0);
-               assert_eq!(scorer.channel_penalty_msat(42, 256_999, Some(1_024_000), &source, &target), 0);
-               assert_eq!(scorer.channel_penalty_msat(42, 257_000, Some(1_024_000), &source, &target), 100);
-               assert_eq!(scorer.channel_penalty_msat(42, 258_000, Some(1_024_000), &source, &target), 200);
-               assert_eq!(scorer.channel_penalty_msat(42, 512_000, Some(1_024_000), &source, &target), 256 * 100);
+               assert_eq!(scorer.channel_penalty_msat(42, 1_000, 1_024_000, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 256_999, 1_024_000, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 257_000, 1_024_000, &source, &target), 100);
+               assert_eq!(scorer.channel_penalty_msat(42, 258_000, 1_024_000, &source, &target), 200);
+               assert_eq!(scorer.channel_penalty_msat(42, 512_000, 1_024_000, &source, &target), 256 * 100);
+       }
+
+       // `ProbabilisticScorer` tests
+
+       /// A probabilistic scorer for testing with time that can be manually advanced.
+       type ProbabilisticScorer<'a> = ProbabilisticScorerUsingTime::<&'a NetworkGraph, SinceEpoch>;
+
+       fn sender_privkey() -> SecretKey {
+               SecretKey::from_slice(&[41; 32]).unwrap()
+       }
+
+       fn recipient_privkey() -> SecretKey {
+               SecretKey::from_slice(&[45; 32]).unwrap()
+       }
+
+       fn sender_pubkey() -> PublicKey {
+               let secp_ctx = Secp256k1::new();
+               PublicKey::from_secret_key(&secp_ctx, &sender_privkey())
+       }
+
+       fn recipient_pubkey() -> PublicKey {
+               let secp_ctx = Secp256k1::new();
+               PublicKey::from_secret_key(&secp_ctx, &recipient_privkey())
+       }
+
+       fn sender_node_id() -> NodeId {
+               NodeId::from_pubkey(&sender_pubkey())
+       }
+
+       fn recipient_node_id() -> NodeId {
+               NodeId::from_pubkey(&recipient_pubkey())
+       }
+
+       fn network_graph() -> NetworkGraph {
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
+               let mut network_graph = NetworkGraph::new(genesis_hash);
+               add_channel(&mut network_graph, 42, source_privkey(), target_privkey());
+               add_channel(&mut network_graph, 43, target_privkey(), recipient_privkey());
+
+               network_graph
+       }
+
+       fn add_channel(
+               network_graph: &mut NetworkGraph, short_channel_id: u64, node_1_key: SecretKey,
+               node_2_key: SecretKey
+       ) {
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
+               let node_1_secret = &SecretKey::from_slice(&[39; 32]).unwrap();
+               let node_2_secret = &SecretKey::from_slice(&[40; 32]).unwrap();
+               let secp_ctx = Secp256k1::new();
+               let unsigned_announcement = UnsignedChannelAnnouncement {
+                       features: ChannelFeatures::known(),
+                       chain_hash: genesis_hash,
+                       short_channel_id,
+                       node_id_1: PublicKey::from_secret_key(&secp_ctx, &node_1_key),
+                       node_id_2: PublicKey::from_secret_key(&secp_ctx, &node_2_key),
+                       bitcoin_key_1: PublicKey::from_secret_key(&secp_ctx, &node_1_secret),
+                       bitcoin_key_2: PublicKey::from_secret_key(&secp_ctx, &node_2_secret),
+                       excess_data: Vec::new(),
+               };
+               let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
+               let signed_announcement = ChannelAnnouncement {
+                       node_signature_1: secp_ctx.sign(&msghash, &node_1_key),
+                       node_signature_2: secp_ctx.sign(&msghash, &node_2_key),
+                       bitcoin_signature_1: secp_ctx.sign(&msghash, &node_1_secret),
+                       bitcoin_signature_2: secp_ctx.sign(&msghash, &node_2_secret),
+                       contents: unsigned_announcement,
+               };
+               let chain_source: Option<&::util::test_utils::TestChainSource> = None;
+               network_graph.update_channel_from_announcement(
+                       &signed_announcement, &chain_source, &secp_ctx).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
+       ) {
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
+               let secp_ctx = Secp256k1::new();
+               let unsigned_update = UnsignedChannelUpdate {
+                       chain_hash: genesis_hash,
+                       short_channel_id,
+                       timestamp: 100,
+                       flags,
+                       cltv_expiry_delta: 18,
+                       htlc_minimum_msat: 0,
+                       htlc_maximum_msat: OptionalField::Present(1_000),
+                       fee_base_msat: 1,
+                       fee_proportional_millionths: 0,
+                       excess_data: Vec::new(),
+               };
+               let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_update.encode()[..])[..]);
+               let signed_update = ChannelUpdate {
+                       signature: secp_ctx.sign(&msghash, &node_key),
+                       contents: unsigned_update,
+               };
+               network_graph.update_channel(&signed_update, &secp_ctx).unwrap();
+       }
+
+       fn payment_path_for_amount(amount_msat: u64) -> Vec<RouteHop> {
+               vec![
+                       RouteHop {
+                               pubkey: source_pubkey(),
+                               node_features: NodeFeatures::known(),
+                               short_channel_id: 41,
+                               channel_features: ChannelFeatures::known(),
+                               fee_msat: 1,
+                               cltv_expiry_delta: 18,
+                       },
+                       RouteHop {
+                               pubkey: target_pubkey(),
+                               node_features: NodeFeatures::known(),
+                               short_channel_id: 42,
+                               channel_features: ChannelFeatures::known(),
+                               fee_msat: 2,
+                               cltv_expiry_delta: 18,
+                       },
+                       RouteHop {
+                               pubkey: recipient_pubkey(),
+                               node_features: NodeFeatures::known(),
+                               short_channel_id: 43,
+                               channel_features: ChannelFeatures::known(),
+                               fee_msat: amount_msat,
+                               cltv_expiry_delta: 18,
+                       },
+               ]
+       }
+
+       #[test]
+       fn liquidity_bounds_directed_from_lowest_node_id() {
+               let last_updated = SinceEpoch::now();
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters::default();
+               let mut scorer = ProbabilisticScorer::new(params, &network_graph)
+                       .with_channel(42,
+                               ChannelLiquidity {
+                                       min_liquidity_offset_msat: 700, max_liquidity_offset_msat: 100, last_updated
+                               })
+                       .with_channel(43,
+                               ChannelLiquidity {
+                                       min_liquidity_offset_msat: 700, max_liquidity_offset_msat: 100, last_updated
+                               });
+               let source = source_node_id();
+               let target = target_node_id();
+               let recipient = recipient_node_id();
+               assert!(source > target);
+               assert!(target < recipient);
+
+               // Update minimum liquidity.
+
+               let liquidity_offset_half_life = scorer.params.liquidity_offset_half_life;
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&source, &target, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 100);
+               assert_eq!(liquidity.max_liquidity_msat(), 300);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&target, &source, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 700);
+               assert_eq!(liquidity.max_liquidity_msat(), 900);
+
+               scorer.channel_liquidities.get_mut(&42).unwrap()
+                       .as_directed_mut(&source, &target, 1_000, liquidity_offset_half_life)
+                       .set_min_liquidity_msat(200);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&source, &target, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 200);
+               assert_eq!(liquidity.max_liquidity_msat(), 300);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&target, &source, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 700);
+               assert_eq!(liquidity.max_liquidity_msat(), 800);
+
+               // Update maximum liquidity.
+
+               let liquidity = scorer.channel_liquidities.get(&43).unwrap()
+                       .as_directed(&target, &recipient, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 700);
+               assert_eq!(liquidity.max_liquidity_msat(), 900);
+
+               let liquidity = scorer.channel_liquidities.get(&43).unwrap()
+                       .as_directed(&recipient, &target, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 100);
+               assert_eq!(liquidity.max_liquidity_msat(), 300);
+
+               scorer.channel_liquidities.get_mut(&43).unwrap()
+                       .as_directed_mut(&target, &recipient, 1_000, liquidity_offset_half_life)
+                       .set_max_liquidity_msat(200);
+
+               let liquidity = scorer.channel_liquidities.get(&43).unwrap()
+                       .as_directed(&target, &recipient, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 0);
+               assert_eq!(liquidity.max_liquidity_msat(), 200);
+
+               let liquidity = scorer.channel_liquidities.get(&43).unwrap()
+                       .as_directed(&recipient, &target, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 800);
+               assert_eq!(liquidity.max_liquidity_msat(), 1000);
+       }
+
+       #[test]
+       fn resets_liquidity_upper_bound_when_crossed_by_lower_bound() {
+               let last_updated = SinceEpoch::now();
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters::default();
+               let mut scorer = ProbabilisticScorer::new(params, &network_graph)
+                       .with_channel(42,
+                               ChannelLiquidity {
+                                       min_liquidity_offset_msat: 200, max_liquidity_offset_msat: 400, last_updated
+                               });
+               let source = source_node_id();
+               let target = target_node_id();
+               assert!(source > target);
+
+               // Check initial bounds.
+               let liquidity_offset_half_life = scorer.params.liquidity_offset_half_life;
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&source, &target, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 400);
+               assert_eq!(liquidity.max_liquidity_msat(), 800);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&target, &source, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 200);
+               assert_eq!(liquidity.max_liquidity_msat(), 600);
+
+               // Reset from source to target.
+               scorer.channel_liquidities.get_mut(&42).unwrap()
+                       .as_directed_mut(&source, &target, 1_000, liquidity_offset_half_life)
+                       .set_min_liquidity_msat(900);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&source, &target, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 900);
+               assert_eq!(liquidity.max_liquidity_msat(), 1_000);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&target, &source, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 0);
+               assert_eq!(liquidity.max_liquidity_msat(), 100);
+
+               // Reset from target to source.
+               scorer.channel_liquidities.get_mut(&42).unwrap()
+                       .as_directed_mut(&target, &source, 1_000, liquidity_offset_half_life)
+                       .set_min_liquidity_msat(400);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&source, &target, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 0);
+               assert_eq!(liquidity.max_liquidity_msat(), 600);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&target, &source, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 400);
+               assert_eq!(liquidity.max_liquidity_msat(), 1_000);
+       }
+
+       #[test]
+       fn resets_liquidity_lower_bound_when_crossed_by_upper_bound() {
+               let last_updated = SinceEpoch::now();
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters::default();
+               let mut scorer = ProbabilisticScorer::new(params, &network_graph)
+                       .with_channel(42,
+                               ChannelLiquidity {
+                                       min_liquidity_offset_msat: 200, max_liquidity_offset_msat: 400, last_updated
+                               });
+               let source = source_node_id();
+               let target = target_node_id();
+               assert!(source > target);
+
+               // Check initial bounds.
+               let liquidity_offset_half_life = scorer.params.liquidity_offset_half_life;
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&source, &target, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 400);
+               assert_eq!(liquidity.max_liquidity_msat(), 800);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&target, &source, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 200);
+               assert_eq!(liquidity.max_liquidity_msat(), 600);
+
+               // Reset from source to target.
+               scorer.channel_liquidities.get_mut(&42).unwrap()
+                       .as_directed_mut(&source, &target, 1_000, liquidity_offset_half_life)
+                       .set_max_liquidity_msat(300);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&source, &target, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 0);
+               assert_eq!(liquidity.max_liquidity_msat(), 300);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&target, &source, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 700);
+               assert_eq!(liquidity.max_liquidity_msat(), 1_000);
+
+               // Reset from target to source.
+               scorer.channel_liquidities.get_mut(&42).unwrap()
+                       .as_directed_mut(&target, &source, 1_000, liquidity_offset_half_life)
+                       .set_max_liquidity_msat(600);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&source, &target, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 400);
+               assert_eq!(liquidity.max_liquidity_msat(), 1_000);
+
+               let liquidity = scorer.channel_liquidities.get(&42).unwrap()
+                       .as_directed(&target, &source, 1_000, liquidity_offset_half_life);
+               assert_eq!(liquidity.min_liquidity_msat(), 0);
+               assert_eq!(liquidity.max_liquidity_msat(), 600);
+       }
+
+       #[test]
+       fn increased_penalty_nearing_liquidity_upper_bound() {
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters {
+                       liquidity_penalty_multiplier_msat: 1_000, ..Default::default()
+               };
+               let scorer = ProbabilisticScorer::new(params, &network_graph);
+               let source = source_node_id();
+               let target = target_node_id();
+
+               assert_eq!(scorer.channel_penalty_msat(42, 100, 100_000, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 1_000, 100_000, &source, &target), 4);
+               assert_eq!(scorer.channel_penalty_msat(42, 10_000, 100_000, &source, &target), 45);
+               assert_eq!(scorer.channel_penalty_msat(42, 100_000, 100_000, &source, &target), 2_000);
+
+               assert_eq!(scorer.channel_penalty_msat(42, 125, 1_000, &source, &target), 57);
+               assert_eq!(scorer.channel_penalty_msat(42, 250, 1_000, &source, &target), 124);
+               assert_eq!(scorer.channel_penalty_msat(42, 375, 1_000, &source, &target), 203);
+               assert_eq!(scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 300);
+               assert_eq!(scorer.channel_penalty_msat(42, 625, 1_000, &source, &target), 425);
+               assert_eq!(scorer.channel_penalty_msat(42, 750, 1_000, &source, &target), 600);
+               assert_eq!(scorer.channel_penalty_msat(42, 875, 1_000, &source, &target), 900);
+       }
+
+       #[test]
+       fn constant_penalty_outside_liquidity_bounds() {
+               let last_updated = SinceEpoch::now();
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters {
+                       liquidity_penalty_multiplier_msat: 1_000, ..Default::default()
+               };
+               let scorer = ProbabilisticScorer::new(params, &network_graph)
+                       .with_channel(42,
+                               ChannelLiquidity {
+                                       min_liquidity_offset_msat: 40, max_liquidity_offset_msat: 40, last_updated
+                               });
+               let source = source_node_id();
+               let target = target_node_id();
+
+               assert_eq!(scorer.channel_penalty_msat(42, 39, 100, &source, &target), 0);
+               assert_ne!(scorer.channel_penalty_msat(42, 50, 100, &source, &target), 0);
+               assert_ne!(scorer.channel_penalty_msat(42, 50, 100, &source, &target), 2_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 61, 100, &source, &target), 2_000);
+       }
+
+       #[test]
+       fn does_not_further_penalize_own_channel() {
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters {
+                       liquidity_penalty_multiplier_msat: 1_000, ..Default::default()
+               };
+               let mut scorer = ProbabilisticScorer::new(params, &network_graph);
+               let sender = sender_node_id();
+               let source = source_node_id();
+               let failed_path = payment_path_for_amount(500);
+               let successful_path = payment_path_for_amount(200);
+
+               assert_eq!(scorer.channel_penalty_msat(41, 500, 1_000, &sender, &source), 300);
+
+               scorer.payment_path_failed(&failed_path.iter().collect::<Vec<_>>(), 41);
+               assert_eq!(scorer.channel_penalty_msat(41, 500, 1_000, &sender, &source), 300);
+
+               scorer.payment_path_successful(&successful_path.iter().collect::<Vec<_>>());
+               assert_eq!(scorer.channel_penalty_msat(41, 500, 1_000, &sender, &source), 300);
+       }
+
+       #[test]
+       fn sets_liquidity_lower_bound_on_downstream_failure() {
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters {
+                       liquidity_penalty_multiplier_msat: 1_000, ..Default::default()
+               };
+               let mut scorer = ProbabilisticScorer::new(params, &network_graph);
+               let source = source_node_id();
+               let target = target_node_id();
+               let path = payment_path_for_amount(500);
+
+               assert_eq!(scorer.channel_penalty_msat(42, 250, 1_000, &source, &target), 124);
+               assert_eq!(scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 300);
+               assert_eq!(scorer.channel_penalty_msat(42, 750, 1_000, &source, &target), 600);
+
+               scorer.payment_path_failed(&path.iter().collect::<Vec<_>>(), 43);
+
+               assert_eq!(scorer.channel_penalty_msat(42, 250, 1_000, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 750, 1_000, &source, &target), 300);
+       }
+
+       #[test]
+       fn sets_liquidity_upper_bound_on_failure() {
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters {
+                       liquidity_penalty_multiplier_msat: 1_000, ..Default::default()
+               };
+               let mut scorer = ProbabilisticScorer::new(params, &network_graph);
+               let source = source_node_id();
+               let target = target_node_id();
+               let path = payment_path_for_amount(500);
+
+               assert_eq!(scorer.channel_penalty_msat(42, 250, 1_000, &source, &target), 124);
+               assert_eq!(scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 300);
+               assert_eq!(scorer.channel_penalty_msat(42, 750, 1_000, &source, &target), 600);
+
+               scorer.payment_path_failed(&path.iter().collect::<Vec<_>>(), 42);
+
+               assert_eq!(scorer.channel_penalty_msat(42, 250, 1_000, &source, &target), 300);
+               assert_eq!(scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 2_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 750, 1_000, &source, &target), 2_000);
+       }
+
+       #[test]
+       fn reduces_liquidity_upper_bound_along_path_on_success() {
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters {
+                       liquidity_penalty_multiplier_msat: 1_000, ..Default::default()
+               };
+               let mut scorer = ProbabilisticScorer::new(params, &network_graph);
+               let sender = sender_node_id();
+               let source = source_node_id();
+               let target = target_node_id();
+               let recipient = recipient_node_id();
+               let path = payment_path_for_amount(500);
+
+               assert_eq!(scorer.channel_penalty_msat(41, 250, 1_000, &sender, &source), 124);
+               assert_eq!(scorer.channel_penalty_msat(42, 250, 1_000, &source, &target), 124);
+               assert_eq!(scorer.channel_penalty_msat(43, 250, 1_000, &target, &recipient), 124);
+
+               scorer.payment_path_successful(&path.iter().collect::<Vec<_>>());
+
+               assert_eq!(scorer.channel_penalty_msat(41, 250, 1_000, &sender, &source), 124);
+               assert_eq!(scorer.channel_penalty_msat(42, 250, 1_000, &source, &target), 300);
+               assert_eq!(scorer.channel_penalty_msat(43, 250, 1_000, &target, &recipient), 300);
+       }
+
+       #[test]
+       fn decays_liquidity_bounds_over_time() {
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters {
+                       liquidity_penalty_multiplier_msat: 1_000,
+                       liquidity_offset_half_life: Duration::from_secs(10),
+               };
+               let mut scorer = ProbabilisticScorer::new(params, &network_graph);
+               let source = source_node_id();
+               let target = target_node_id();
+
+               assert_eq!(scorer.channel_penalty_msat(42, 0, 1_024, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 1_024, 1_024, &source, &target), 2_000);
+
+               scorer.payment_path_failed(&payment_path_for_amount(768).iter().collect::<Vec<_>>(), 42);
+               scorer.payment_path_failed(&payment_path_for_amount(128).iter().collect::<Vec<_>>(), 43);
+
+               assert_eq!(scorer.channel_penalty_msat(42, 128, 1_024, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 256, 1_024, &source, &target), 92);
+               assert_eq!(scorer.channel_penalty_msat(42, 768, 1_024, &source, &target), 1_424);
+               assert_eq!(scorer.channel_penalty_msat(42, 896, 1_024, &source, &target), 2_000);
+
+               SinceEpoch::advance(Duration::from_secs(9));
+               assert_eq!(scorer.channel_penalty_msat(42, 128, 1_024, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 256, 1_024, &source, &target), 92);
+               assert_eq!(scorer.channel_penalty_msat(42, 768, 1_024, &source, &target), 1_424);
+               assert_eq!(scorer.channel_penalty_msat(42, 896, 1_024, &source, &target), 2_000);
+
+               SinceEpoch::advance(Duration::from_secs(1));
+               assert_eq!(scorer.channel_penalty_msat(42, 64, 1_024, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 128, 1_024, &source, &target), 34);
+               assert_eq!(scorer.channel_penalty_msat(42, 896, 1_024, &source, &target), 1_812);
+               assert_eq!(scorer.channel_penalty_msat(42, 960, 1_024, &source, &target), 2_000);
+
+               // Fully decay liquidity lower bound.
+               SinceEpoch::advance(Duration::from_secs(10 * 7));
+               assert_eq!(scorer.channel_penalty_msat(42, 0, 1_024, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 1, 1_024, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 1_023, 1_024, &source, &target), 2_000);
+               assert_eq!(scorer.channel_penalty_msat(42, 1_024, 1_024, &source, &target), 2_000);
+
+               // Fully decay liquidity upper bound.
+               SinceEpoch::advance(Duration::from_secs(10));
+               assert_eq!(scorer.channel_penalty_msat(42, 0, 1_024, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 1_024, 1_024, &source, &target), 2_000);
+
+               SinceEpoch::advance(Duration::from_secs(10));
+               assert_eq!(scorer.channel_penalty_msat(42, 0, 1_024, &source, &target), 0);
+               assert_eq!(scorer.channel_penalty_msat(42, 1_024, 1_024, &source, &target), 2_000);
+       }
+
+       #[test]
+       fn decays_liquidity_bounds_without_shift_overflow() {
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters {
+                       liquidity_penalty_multiplier_msat: 1_000,
+                       liquidity_offset_half_life: Duration::from_secs(10),
+               };
+               let mut scorer = ProbabilisticScorer::new(params, &network_graph);
+               let source = source_node_id();
+               let target = target_node_id();
+               assert_eq!(scorer.channel_penalty_msat(42, 256, 1_024, &source, &target), 124);
+
+               scorer.payment_path_failed(&payment_path_for_amount(512).iter().collect::<Vec<_>>(), 42);
+               assert_eq!(scorer.channel_penalty_msat(42, 256, 1_024, &source, &target), 281);
+
+               // An unchecked right shift 64 bits or more in DirectedChannelLiquidity::decayed_offset_msat
+               // would cause an overflow.
+               SinceEpoch::advance(Duration::from_secs(10 * 64));
+               assert_eq!(scorer.channel_penalty_msat(42, 256, 1_024, &source, &target), 124);
+
+               SinceEpoch::advance(Duration::from_secs(10));
+               assert_eq!(scorer.channel_penalty_msat(42, 256, 1_024, &source, &target), 124);
+       }
+
+       #[test]
+       fn restricts_liquidity_bounds_after_decay() {
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters {
+                       liquidity_penalty_multiplier_msat: 1_000,
+                       liquidity_offset_half_life: Duration::from_secs(10),
+               };
+               let mut scorer = ProbabilisticScorer::new(params, &network_graph);
+               let source = source_node_id();
+               let target = target_node_id();
+
+               assert_eq!(scorer.channel_penalty_msat(42, 512, 1_024, &source, &target), 300);
+
+               // More knowledge gives higher confidence (256, 768), meaning a lower penalty.
+               scorer.payment_path_failed(&payment_path_for_amount(768).iter().collect::<Vec<_>>(), 42);
+               scorer.payment_path_failed(&payment_path_for_amount(256).iter().collect::<Vec<_>>(), 43);
+               assert_eq!(scorer.channel_penalty_msat(42, 512, 1_024, &source, &target), 281);
+
+               // Decaying knowledge gives less confidence (128, 896), meaning a higher penalty.
+               SinceEpoch::advance(Duration::from_secs(10));
+               assert_eq!(scorer.channel_penalty_msat(42, 512, 1_024, &source, &target), 293);
+
+               // Reducing the upper bound gives more confidence (128, 832) that the payment amount (512)
+               // is closer to the upper bound, meaning a higher penalty.
+               scorer.payment_path_successful(&payment_path_for_amount(64).iter().collect::<Vec<_>>());
+               assert_eq!(scorer.channel_penalty_msat(42, 512, 1_024, &source, &target), 333);
+
+               // Increasing the lower bound gives more confidence (256, 832) that the payment amount (512)
+               // is closer to the lower bound, meaning a lower penalty.
+               scorer.payment_path_failed(&payment_path_for_amount(256).iter().collect::<Vec<_>>(), 43);
+               assert_eq!(scorer.channel_penalty_msat(42, 512, 1_024, &source, &target), 247);
+
+               // Further decaying affects the lower bound more than the upper bound (128, 928).
+               SinceEpoch::advance(Duration::from_secs(10));
+               assert_eq!(scorer.channel_penalty_msat(42, 512, 1_024, &source, &target), 280);
+       }
+
+       #[test]
+       fn restores_persisted_liquidity_bounds() {
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters {
+                       liquidity_penalty_multiplier_msat: 1_000,
+                       liquidity_offset_half_life: Duration::from_secs(10),
+               };
+               let mut scorer = ProbabilisticScorer::new(params, &network_graph);
+               let source = source_node_id();
+               let target = target_node_id();
+
+               scorer.payment_path_failed(&payment_path_for_amount(500).iter().collect::<Vec<_>>(), 42);
+               assert_eq!(scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 2_000);
+
+               SinceEpoch::advance(Duration::from_secs(10));
+               assert_eq!(scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 475);
+
+               scorer.payment_path_failed(&payment_path_for_amount(250).iter().collect::<Vec<_>>(), 43);
+               assert_eq!(scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 300);
+
+               let mut serialized_scorer = Vec::new();
+               scorer.write(&mut serialized_scorer).unwrap();
+
+               let mut serialized_scorer = io::Cursor::new(&serialized_scorer);
+               let deserialized_scorer =
+                       <ProbabilisticScorer>::read(&mut serialized_scorer, (params, &network_graph)).unwrap();
+               assert_eq!(deserialized_scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 300);
+       }
+
+       #[test]
+       fn decays_persisted_liquidity_bounds() {
+               let network_graph = network_graph();
+               let params = ProbabilisticScoringParameters {
+                       liquidity_penalty_multiplier_msat: 1_000,
+                       liquidity_offset_half_life: Duration::from_secs(10),
+               };
+               let mut scorer = ProbabilisticScorer::new(params, &network_graph);
+               let source = source_node_id();
+               let target = target_node_id();
+
+               scorer.payment_path_failed(&payment_path_for_amount(500).iter().collect::<Vec<_>>(), 42);
+               assert_eq!(scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 2_000);
+
+               let mut serialized_scorer = Vec::new();
+               scorer.write(&mut serialized_scorer).unwrap();
+
+               SinceEpoch::advance(Duration::from_secs(10));
+
+               let mut serialized_scorer = io::Cursor::new(&serialized_scorer);
+               let deserialized_scorer =
+                       <ProbabilisticScorer>::read(&mut serialized_scorer, (params, &network_graph)).unwrap();
+               assert_eq!(deserialized_scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 475);
+
+               scorer.payment_path_failed(&payment_path_for_amount(250).iter().collect::<Vec<_>>(), 43);
+               assert_eq!(scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 300);
+
+               SinceEpoch::advance(Duration::from_secs(10));
+               assert_eq!(deserialized_scorer.channel_penalty_msat(42, 500, 1_000, &source, &target), 367);
        }
 }
index dee6907832ea1c974a8209571dfd186b8fa2e557..0e1c92d009c112cbc74c6f811a5fc9d158f56dd3 100644 (file)
@@ -21,8 +21,7 @@ use ln::features::{ChannelFeatures, InitFeatures};
 use ln::msgs;
 use ln::msgs::OptionalField;
 use ln::script::ShutdownScript;
-use routing::scoring::ScorerUsingTime;
-use routing::scoring::time::Eternity;
+use routing::scoring::FixedPenaltyScorer;
 use util::enforcing_trait_impls::{EnforcingSigner, EnforcementState};
 use util::events;
 use util::logger::{Logger, Level, Record};
@@ -724,4 +723,4 @@ impl core::fmt::Debug for OnRegisterOutput {
 }
 
 /// A scorer useful in testing, when the passage of time isn't a concern.
-pub type TestScorer = ScorerUsingTime<Eternity>;
+pub type TestScorer = FixedPenaltyScorer;