ln: add experimental accountable signal to update_add_htlc

Author: carlaKC

lightning/src/ln/blinded_payment_tests.rs

@@ -1502,6 +1502,7 @@ fn update_add_msg(
 		skimmed_fee_msat: None,
 		blinding_point,
 		hold_htlc: None,
+		accountable: None,
 	}
 }
 

lightning/src/ln/channel.rs

@@ -9652,6 +9652,7 @@ where
 					skimmed_fee_msat: htlc.skimmed_fee_msat,
 					blinding_point: htlc.blinding_point,
 					hold_htlc: htlc.hold_htlc,
+					accountable: None,
 				});
 			}
 		}

lightning/src/ln/functional_tests.rs

@@ -2270,6 +2270,7 @@ pub fn fail_backward_pending_htlc_upon_channel_failure() {
 			skimmed_fee_msat: None,
 			blinding_point: None,
 			hold_htlc: None,
+			accountable: None,
 		};
 		nodes[0].node.handle_update_add_htlc(node_b_id, &update_add_htlc);
 	}

lightning/src/ln/htlc_reserve_unit_tests.rs

@@ -839,6 +839,7 @@ pub fn do_test_fee_spike_buffer(cfg: Option<UserConfig>, htlc_fails: bool) {
 		skimmed_fee_msat: None,
 		blinding_point: None,
 		hold_htlc: None,
+		accountable: None,
 	};
 
 	nodes[1].node.handle_update_add_htlc(node_a_id, &msg);
@@ -1082,6 +1083,7 @@ pub fn test_chan_reserve_violation_inbound_htlc_outbound_channel() {
 		skimmed_fee_msat: None,
 		blinding_point: None,
 		hold_htlc: None,
+		accountable: None,
 	};
 
 	nodes[0].node.handle_update_add_htlc(node_b_id, &msg);
@@ -1266,6 +1268,7 @@ pub fn test_chan_reserve_violation_inbound_htlc_inbound_chan() {
 		skimmed_fee_msat: None,
 		blinding_point: None,
 		hold_htlc: None,
+		accountable: None,
 	};
 
 	nodes[1].node.handle_update_add_htlc(node_a_id, &msg);
@@ -1650,6 +1653,7 @@ pub fn test_update_add_htlc_bolt2_receiver_check_max_htlc_limit() {
 		skimmed_fee_msat: None,
 		blinding_point: None,
 		hold_htlc: None,
+		accountable: None,
 	};
 
 	for i in 0..50 {
@@ -2256,6 +2260,7 @@ pub fn do_test_dust_limit_fee_accounting(can_afford: bool) {
 		skimmed_fee_msat: None,
 		blinding_point: None,
 		hold_htlc: None,
+		accountable: None,
 	};
 
 	nodes[1].node.handle_update_add_htlc(node_a_id, &msg);

lightning/src/ln/msgs.rs

@@ -768,6 +768,28 @@ pub struct UpdateAddHTLC {
 	///
 	/// [`ReleaseHeldHtlc`]: crate::onion_message::async_payments::ReleaseHeldHtlc
 	pub hold_htlc: Option<()>,
+	/// An experimental field indicating whether the receiving node's reputation would be held
+	/// accountable for the timely resolution of the HTLC.
+	///
+	/// Note that this field is [`experimental`] so should not be used for forwarding decisions.
+	///
+	/// [`experimental`]: https://github.com/lightning/blips/blob/master/blip-0004.md
+	pub accountable: ExperimentalAccountable,
+}
+
+/// Represents the value sent on the wire to signal experimental accountability. For historical
+/// reasons the least significant three bits are used to represent the accountable signal's value,
+/// though it is now only interpreted as a binary value.
+pub type ExperimentalAccountable = Option<u8>;
+
+/// Converts a boolean accountable signal to its wire representation.
+pub fn accountable_from_bool(value: bool) -> ExperimentalAccountable {
+	Some(if value { 7 } else { 0 })
+}
+
+/// Converts the accountable signal on the wire to a boolean signal.
+pub fn accountable_into_bool(accountable: ExperimentalAccountable) -> Option<bool> {
+	accountable.map(|v| v == 7)
 }
 
 /// An [`onion message`] to be sent to or received from a peer.
@@ -3373,6 +3395,7 @@ impl_writeable_msg!(UpdateAddHTLC, {
 	// TODO: currently we may fail to read the `ChannelManager` if we write a new even TLV in this message
 	// and then downgrade. Once this is fixed, update the type here to match BOLTs PR 989.
 	(75537, hold_htlc, option),
+	(106823, accountable, option),
 });
 
 impl LengthReadable for OnionMessage {
@@ -5872,6 +5895,7 @@ mod tests {
 			skimmed_fee_msat: None,
 			blinding_point: None,
 			hold_htlc: None,
+			accountable: None,
 		};
 		let encoded_value = update_add_htlc.encode();
 		let target_value = <Vec<u8>>::from_hex("020202020202020202020202020202020202020202020202020202020202020200083a840000034d32144668701144760101010101010101010101010101010101010101010101010101010101010101000c89d4ff031b84c5567b126440995d3ed5aaba0565d71e1834604819ff9c17f5e9d5dd078f010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010202020202020202020202020202020202020202020202020202020202020202").unwrap();

lightning/src/ln/onion_payment.rs

@@ -758,6 +758,7 @@ mod tests {
 			skimmed_fee_msat: None,
 			blinding_point: None,
 			hold_htlc: None,
+			accountable: None,
 		}
 	}
 

lightning/src/ln/payment_tests.rs

@@ -5103,6 +5103,7 @@ fn peel_payment_onion_custom_tlvs() {
 		onion_routing_packet,
 		blinding_point: None,
 		hold_htlc: None,
+		accountable: None,
 	};
 	let peeled_onion = crate::ln::onion_payment::peel_payment_onion(
 		&update_add,