Merge pull request #2831 from jkczyz/2024-01-fix-cltv-expiry-delta

Use consistent `cltv_expiry_delta` in `ForwardTlvs`

Author: TheBlueMatt

lightning/src/blinded_path/payment.rs

@@ -97,12 +97,24 @@ pub struct PaymentConstraints {
 	pub htlc_minimum_msat: u64,
 }
 
-impl From<CounterpartyForwardingInfo> for PaymentRelay {
-	fn from(info: CounterpartyForwardingInfo) -> Self {
+impl TryFrom<CounterpartyForwardingInfo> for PaymentRelay {
+	type Error = ();
+
+	fn try_from(info: CounterpartyForwardingInfo) -> Result<Self, ()> {
 		let CounterpartyForwardingInfo {
 			fee_base_msat, fee_proportional_millionths, cltv_expiry_delta
 		} = info;
-		Self { cltv_expiry_delta, fee_proportional_millionths, fee_base_msat }
+
+		// Avoid exposing esoteric CLTV expiry deltas
+		let cltv_expiry_delta = match cltv_expiry_delta {
+			0..=40 => 40,
+			41..=80 => 80,
+			81..=144 => 144,
+			145..=216 => 216,
+			_ => return Err(()),
+		};
+
+		Ok(Self { cltv_expiry_delta, fee_proportional_millionths, fee_base_msat })
 	}
 }
 

lightning/src/routing/router.rs

@@ -114,19 +114,14 @@ impl<G: Deref<Target = NetworkGraph<L>> + Clone, L: Deref, S: Deref, SP: Sized,
 					None => return None,
 				};
 				let payment_relay: PaymentRelay = match details.counterparty.forwarding_info {
-					Some(forwarding_info) => forwarding_info.into(),
+					Some(forwarding_info) => match forwarding_info.try_into() {
+						Ok(payment_relay) => payment_relay,
+						Err(()) => return None,
+					},
 					None => return None,
 				};
 
-				// Avoid exposing esoteric CLTV expiry deltas
-				let cltv_expiry_delta = match payment_relay.cltv_expiry_delta {
-					0..=40 => 40u32,
-					41..=80 => 80u32,
-					81..=144 => 144u32,
-					145..=216 => 216u32,
-					_ => return None,
-				};
-
+				let cltv_expiry_delta = payment_relay.cltv_expiry_delta as u32;
 				let payment_constraints = PaymentConstraints {
 					max_cltv_expiry: tlvs.payment_constraints.max_cltv_expiry + cltv_expiry_delta,
 					htlc_minimum_msat: details.inbound_htlc_minimum_msat.unwrap_or(0),