f add buffer to amount and cltv delta estimates

Author: valentinewallace

lightning/src/ln/onion_utils.rs

@@ -16,7 +16,9 @@ use crate::ln::msgs;
 use crate::ln::types::{PaymentHash, PaymentPreimage};
 use crate::ln::wire::Encode;
 use crate::routing::gossip::NetworkUpdate;
-use crate::routing::router::{Path, Payee, RouteHop, RouteParameters, MAX_PATH_LENGTH_ESTIMATE};
+use crate::routing::router::{
+	Path, RouteHop, RouteParameters, DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, MAX_PATH_LENGTH_ESTIMATE,
+};
 use crate::sign::NodeSigner;
 use crate::util::errors::{self, APIError};
 use crate::util::logger::Logger;
@@ -324,46 +326,44 @@ pub(crate) fn set_max_path_length(
 	.serialized_length()
 	.saturating_add(PAYLOAD_HMAC_LEN);
 
-	let (cltv_expiry_delta, num_reserved_hops, blinded_tail_opt) =
-		match &route_params.payment_params.payee {
-			Payee::Blinded { route_hints, .. } => {
-				let (blinded_payinfo, largest_path) = route_hints
-					.iter()
-					.max_by(|(_, path_a), (_, path_b)| {
-						path_a.serialized_length().cmp(&path_b.serialized_length())
-					})
-					.ok_or(())?;
-				let blinded_tail = BlindedTailHopIter {
-					hops: largest_path.blinded_hops.iter(),
-					blinding_point: largest_path.blinding_point,
-					final_value_msat: route_params.final_value_msat,
-					excess_final_cltv_expiry_delta: 0,
-				};
-				(
-					blinded_payinfo.cltv_expiry_delta as u32,
-					largest_path.blinded_hops.len(),
-					Some(blinded_tail),
-				)
-			},
-			Payee::Clear { final_cltv_expiry_delta, .. } => {
-				(*final_cltv_expiry_delta, 1 as usize, None)
-			},
-		};
+	const MIN_FINAL_VALUE_ESTIMATE_WITH_OVERPAY: u64 = 100_000_000;
+	let final_value_msat_with_overpay_buffer = core::cmp::max(
+		route_params.final_value_msat.saturating_mul(4),
+		MIN_FINAL_VALUE_ESTIMATE_WITH_OVERPAY,
+	);
+
+	let (num_reserved_hops, blinded_tail_opt) = route_params
+		.payment_params
+		.payee
+		.blinded_route_hints()
+		.iter()
+		.map(|(_, path)| path)
+		.max_by(|path_a, path_b| path_a.serialized_length().cmp(&path_b.serialized_length()))
+		.map(|largest_path| {
+			let blinded_tail = BlindedTailHopIter {
+				hops: largest_path.blinded_hops.iter(),
+				blinding_point: largest_path.blinding_point,
+				final_value_msat: final_value_msat_with_overpay_buffer,
+				excess_final_cltv_expiry_delta: 0,
+			};
+			(largest_path.blinded_hops.len(), Some(blinded_tail))
+		})
+		.unwrap_or((1, None));
 
 	let unblinded_route_hop = RouteHop {
 		pubkey: PublicKey::from_slice(&[2; 33]).unwrap(),
 		node_features: NodeFeatures::empty(),
 		short_channel_id: 42,
 		channel_features: ChannelFeatures::empty(),
-		fee_msat: route_params.final_value_msat,
-		cltv_expiry_delta,
+		fee_msat: final_value_msat_with_overpay_buffer,
+		cltv_expiry_delta: DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA,
 		maybe_announced_channel: false,
 	};
 	let mut num_reserved_bytes: usize = 0;
 	let build_payloads_res = build_onion_payloads_callback(
 		core::iter::once(&unblinded_route_hop),
 		blinded_tail_opt,
-		route_params.final_value_msat,
+		final_value_msat_with_overpay_buffer,
 		&recipient_onion,
 		best_block_height,
 		&keysend_preimage,