Use correct penalty and CLTV delta in route hints

For route hints, the aggregate next hops path penalty and CLTV delta
should be computed after considering each hop rather than before.
Otherwise, these aggregate values will include values from the current
hop, too.

Author: jkczyz

lightning/src/routing/router.rs

@@ -1295,16 +1295,6 @@ where L::Target: Logger {
 							short_channel_id: hop.short_channel_id,
 						})
 						.unwrap_or_else(|| CandidateRouteHop::PrivateHop { hint: hop });
-					let amount_to_transfer_msat = final_value_msat + aggregate_next_hops_fee_msat;
-					let capacity_msat = candidate.effective_capacity().as_msat();
-					aggregate_next_hops_path_penalty_msat = aggregate_next_hops_path_penalty_msat
-						.saturating_add(scorer.channel_penalty_msat(hop.short_channel_id, amount_to_transfer_msat, capacity_msat, &source, &target));
-
-					aggregate_next_hops_cltv_delta = aggregate_next_hops_cltv_delta
-						.saturating_add(hop.cltv_expiry_delta as u32);
-
-					aggregate_next_hops_path_length = aggregate_next_hops_path_length
-						.saturating_add(1);
 
 					if !add_entry!(candidate, source, target, aggregate_next_hops_fee_msat,
 								path_value_msat, aggregate_next_hops_path_htlc_minimum_msat,
@@ -1316,6 +1306,17 @@ where L::Target: Logger {
 						hop_used = false;
 					}
 
+					let amount_to_transfer_msat = final_value_msat + aggregate_next_hops_fee_msat;
+					let capacity_msat = candidate.effective_capacity().as_msat();
+					aggregate_next_hops_path_penalty_msat = aggregate_next_hops_path_penalty_msat
+						.saturating_add(scorer.channel_penalty_msat(hop.short_channel_id, amount_to_transfer_msat, capacity_msat, &source, &target));
+
+					aggregate_next_hops_cltv_delta = aggregate_next_hops_cltv_delta
+						.saturating_add(hop.cltv_expiry_delta as u32);
+
+					aggregate_next_hops_path_length = aggregate_next_hops_path_length
+						.saturating_add(1);
+
 					// Searching for a direct channel between last checked hop and first_hop_targets
 					if let Some(first_channels) = first_hop_targets.get(&NodeId::from_pubkey(&prev_hop_id)) {
 						for details in first_channels {