f - limit the number of blinded payment paths computed

Author: jkczyz

lightning/src/routing/router.rs

@@ -90,6 +90,9 @@ impl< G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized,
 		&self, recipient: PublicKey, first_hops: Vec<ChannelDetails>, tlvs: ReceiveTlvs,
 		amount_msats: u64, entropy_source: &ES, secp_ctx: &Secp256k1<T>
 	) -> Result<Vec<(BlindedPayInfo, BlindedPath)>, ()> {
+		// Limit the number of blinded paths that are computed.
+		const MAX_PAYMENT_PATHS: usize = 3;
+
 		// Ensure peers have at least three channels so that it is more difficult to infer the
 		// recipient's node_id.
 		const MIN_PEER_CHANNELS: usize = 3;
@@ -127,6 +130,7 @@ impl< G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized,
 					&[forward_node], recipient, tlvs.clone(), u64::MAX, entropy_source, secp_ctx
 				)
 			})
+			.take(MAX_PAYMENT_PATHS)
 			.collect()
 	}
 }