Account for Path::blinded_tail in InflightHtlcs::process_path

diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs
index 28ca2c4bfc700d2509cfa00539472546e154797f..e441f53916d3eb0dee2bbcbb9de933433f12750c 100644 (file)
--- a/lightning/src/routing/router.rs
+++ b/lightning/src/routing/router.rs
@@ -172,6 +172,12 @@ impl InFlightHtlcs {
        /// Takes in a path with payer's node id and adds the path's details to `InFlightHtlcs`.
        pub fn process_path(&mut self, path: &Path, payer_node_id: PublicKey) {
                if path.hops.is_empty() { return };
+
+               let mut cumulative_msat = 0;
+               if let Some(tail) = &path.blinded_tail {
+                       cumulative_msat += tail.final_value_msat;
+               }
+
                // total_inflight_map needs to be direction-sensitive when keeping track of the HTLC value
                // that is held up. However, the `hops` array, which is a path returned by `find_route` in
                // the router excludes the payer node. In the following lines, the payer's information is
@@ -180,7 +186,6 @@ impl InFlightHtlcs {
                let reversed_hops_with_payer = path.hops.iter().rev().skip(1)
                        .map(|hop| hop.pubkey)
                        .chain(core::iter::once(payer_node_id));
-               let mut cumulative_msat = 0;
 
                // Taking the reversed vector from above, we zip it with just the reversed hops list to
                // work "backwards" of the given path, since the last hop's `fee_msat` actually represents
@@ -2267,7 +2272,7 @@ mod tests {
        use crate::routing::gossip::{NetworkGraph, P2PGossipSync, NodeId, EffectiveCapacity};
        use crate::routing::utxo::UtxoResult;
        use crate::routing::router::{get_route, build_route_from_hops_internal, add_random_cltv_offset, default_node_features,
-               BlindedTail, Path, PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees,
+               BlindedTail, InFlightHtlcs, Path, PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees,
                DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, MAX_PATH_LENGTH_ESTIMATE};
        use crate::routing::scoring::{ChannelUsage, FixedPenaltyScorer, Score, ProbabilisticScorer, ProbabilisticScoringParameters};
        use crate::routing::test_utils::{add_channel, add_or_update_node, build_graph, build_line_graph, id_to_feature_flags, get_nodes, update_channel};
@@ -5828,6 +5833,45 @@ mod tests {
                assert_eq!(decoded_route.paths[0].blinded_tail, route.paths[0].blinded_tail);
                assert_eq!(decoded_route.paths[1].blinded_tail, route.paths[1].blinded_tail);
        }
+
+       #[test]
+       fn blinded_path_inflight_processing() {
+               // Ensure we'll score the channel that's inbound to a blinded path's introduction node, and
+               // account for the blinded tail's final amount_msat.
+               let mut inflight_htlcs = InFlightHtlcs::new();
+               let blinded_path = BlindedPath {
+                       introduction_node_id: ln_test_utils::pubkey(43),
+                       blinding_point: ln_test_utils::pubkey(48),
+                       blinded_hops: vec![BlindedHop { blinded_node_id: ln_test_utils::pubkey(49), encrypted_payload: Vec::new() }],
+               };
+               let path = Path {
+                       hops: vec![RouteHop {
+                               pubkey: ln_test_utils::pubkey(42),
+                               node_features: NodeFeatures::empty(),
+                               short_channel_id: 42,
+                               channel_features: ChannelFeatures::empty(),
+                               fee_msat: 100,
+                               cltv_expiry_delta: 0,
+                       },
+                       RouteHop {
+                               pubkey: blinded_path.introduction_node_id,
+                               node_features: NodeFeatures::empty(),
+                               short_channel_id: 43,
+                               channel_features: ChannelFeatures::empty(),
+                               fee_msat: 1,
+                               cltv_expiry_delta: 0,
+                       }],
+                       blinded_tail: Some(BlindedTail {
+                               hops: blinded_path.blinded_hops,
+                               blinding_point: blinded_path.blinding_point,
+                               excess_final_cltv_expiry_delta: 0,
+                               final_value_msat: 200,
+                       }),
+               };
+               inflight_htlcs.process_path(&path, ln_test_utils::pubkey(44));
+               assert_eq!(*inflight_htlcs.0.get(&(42, true)).unwrap(), 301);
+               assert_eq!(*inflight_htlcs.0.get(&(43, false)).unwrap(), 201);
+       }
 }
 
 #[cfg(all(test, not(feature = "no-std")))]