approach-3: Set outgoing accountable in process_pending_forwards

lightning/src/ln/blinded_payment_tests.rs

@@ -1521,6 +1521,7 @@ fn update_add_msg(
 		skimmed_fee_msat: None,
 		blinding_point,
 		hold_htlc: None,
+		accountable: None,
 	}
 }
 

lightning/src/ln/channel.rs

@@ -428,6 +428,7 @@ struct OutboundHTLCOutput {
 	skimmed_fee_msat: Option<u64>,
 	send_timestamp: Option<Duration>,
 	hold_htlc: Option<()>,
+	accountable: Option<u8>,
 }
 
 /// See AwaitingRemoteRevoke ChannelState for more info
@@ -445,6 +446,7 @@ enum HTLCUpdateAwaitingACK {
 		skimmed_fee_msat: Option<u64>,
 		blinding_point: Option<PublicKey>,
 		hold_htlc: Option<()>,
+		accountable: Option<u8>,
 	},
 	ClaimHTLC {
 		payment_preimage: PaymentPreimage,
@@ -8294,7 +8296,7 @@ where
 						skimmed_fee_msat,
 						blinding_point,
 						hold_htlc,
-						..
+						accountable,
 					} => {
 						match self.send_htlc(
 							amount_msat,
@@ -8306,6 +8308,7 @@ where
 							skimmed_fee_msat,
 							blinding_point,
 							hold_htlc.is_some(),
+							accountable,
 							fee_estimator,
 							logger,
 						) {
@@ -9619,6 +9622,7 @@ where
 					skimmed_fee_msat: htlc.skimmed_fee_msat,
 					blinding_point: htlc.blinding_point,
 					hold_htlc: htlc.hold_htlc,
+					accountable: htlc.accountable,
 				});
 			}
 		}
@@ -12441,7 +12445,8 @@ where
 	pub fn queue_add_htlc<F: Deref, L: Deref>(
 		&mut self, amount_msat: u64, payment_hash: PaymentHash, cltv_expiry: u32,
 		source: HTLCSource, onion_routing_packet: msgs::OnionPacket, skimmed_fee_msat: Option<u64>,
-		blinding_point: Option<PublicKey>, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
+		blinding_point: Option<PublicKey>, accountable: Option<u8>,
+		fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
 	) -> Result<(), (LocalHTLCFailureReason, String)>
 	where
 		F::Target: FeeEstimator,
@@ -12458,6 +12463,7 @@ where
 			blinding_point,
 			// This method is only called for forwarded HTLCs, which are never held at the next hop
 			false,
+			accountable,
 			fee_estimator,
 			logger,
 		)
@@ -12489,7 +12495,7 @@ where
 		&mut self, amount_msat: u64, payment_hash: PaymentHash, cltv_expiry: u32,
 		source: HTLCSource, onion_routing_packet: msgs::OnionPacket, mut force_holding_cell: bool,
 		skimmed_fee_msat: Option<u64>, blinding_point: Option<PublicKey>, hold_htlc: bool,
-		fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
+		accountable: Option<u8>, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
 	) -> Result<bool, (LocalHTLCFailureReason, String)>
 	where
 		F::Target: FeeEstimator,
@@ -12571,6 +12577,7 @@ where
 				skimmed_fee_msat,
 				blinding_point,
 				hold_htlc: hold_htlc.then(|| ()),
+				accountable,
 			});
 			return Ok(false);
 		}
@@ -12593,6 +12600,7 @@ where
 			skimmed_fee_msat,
 			send_timestamp,
 			hold_htlc: hold_htlc.then(|| ()),
+			accountable,
 		});
 		self.context.next_holder_htlc_id += 1;
 
@@ -12819,7 +12827,8 @@ where
 	pub fn send_htlc_and_commit<F: Deref, L: Deref>(
 		&mut self, amount_msat: u64, payment_hash: PaymentHash, cltv_expiry: u32,
 		source: HTLCSource, onion_routing_packet: msgs::OnionPacket, skimmed_fee_msat: Option<u64>,
-		hold_htlc: bool, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
+		hold_htlc: bool, accountable: Option<u8>, fee_estimator: &LowerBoundedFeeEstimator<F>,
+		logger: &L,
 	) -> Result<Option<ChannelMonitorUpdate>, ChannelError>
 	where
 		F::Target: FeeEstimator,
@@ -12835,6 +12844,7 @@ where
 			skimmed_fee_msat,
 			None,
 			hold_htlc,
+			accountable,
 			fee_estimator,
 			logger,
 		);
@@ -14439,6 +14449,7 @@ where
 		let mut pending_outbound_skimmed_fees: Vec<Option<u64>> = Vec::new();
 		let mut pending_outbound_blinding_points: Vec<Option<PublicKey>> = Vec::new();
 		let mut pending_outbound_held_htlc_flags: Vec<Option<()>> = Vec::new();
+		let mut pending_outbound_accountable: Vec<Option<u8>> = Vec::new();
 
 		(self.context.pending_outbound_htlcs.len() as u64).write(writer)?;
 		for htlc in self.context.pending_outbound_htlcs.iter() {
@@ -14482,6 +14493,7 @@ where
 			pending_outbound_skimmed_fees.push(htlc.skimmed_fee_msat);
 			pending_outbound_blinding_points.push(htlc.blinding_point);
 			pending_outbound_held_htlc_flags.push(htlc.hold_htlc);
+			pending_outbound_accountable.push(htlc.accountable);
 		}
 
 		let holding_cell_htlc_update_count = self.context.holding_cell_htlc_updates.len();
@@ -14493,6 +14505,8 @@ where
 			Vec::with_capacity(holding_cell_htlc_update_count);
 		let mut holding_cell_held_htlc_flags: Vec<Option<()>> =
 			Vec::with_capacity(holding_cell_htlc_update_count);
+		let mut holding_cell_accountable_flags: Vec<Option<u8>> =
+			Vec::with_capacity(holding_cell_htlc_update_count);
 		// Vec of (htlc_id, failure_code, sha256_of_onion)
 		let mut malformed_htlcs: Vec<(u64, u16, [u8; 32])> = Vec::new();
 		(holding_cell_htlc_update_count as u64).write(writer)?;
@@ -14507,6 +14521,7 @@ where
 					blinding_point,
 					skimmed_fee_msat,
 					hold_htlc,
+					accountable,
 				} => {
 					0u8.write(writer)?;
 					amount_msat.write(writer)?;
@@ -14518,6 +14533,7 @@ where
 					holding_cell_skimmed_fees.push(skimmed_fee_msat);
 					holding_cell_blinding_points.push(blinding_point);
 					holding_cell_held_htlc_flags.push(hold_htlc);
+					holding_cell_accountable_flags.push(accountable);
 				},
 				&HTLCUpdateAwaitingACK::ClaimHTLC {
 					ref payment_preimage,
@@ -14772,6 +14788,8 @@ where
 			(65, self.quiescent_action, option), // Added in 0.2
 			(67, pending_outbound_held_htlc_flags, optional_vec), // Added in 0.2
 			(69, holding_cell_held_htlc_flags, optional_vec), // Added in 0.2
+			(71, holding_cell_accountable_flags, optional_vec), // Added in 0.3
+			(73, pending_outbound_accountable, optional_vec), // Added in 0.3
 		});
 
 		Ok(())
@@ -14921,6 +14939,7 @@ where
 				blinding_point: None,
 				send_timestamp: None,
 				hold_htlc: None,
+				accountable: None,
 			});
 		}
 
@@ -14940,6 +14959,7 @@ where
 					skimmed_fee_msat: None,
 					blinding_point: None,
 					hold_htlc: None,
+					accountable: None,
 				},
 				1 => HTLCUpdateAwaitingACK::ClaimHTLC {
 					payment_preimage: Readable::read(reader)?,
@@ -15139,6 +15159,8 @@ where
 
 		let mut pending_outbound_held_htlc_flags_opt: Option<Vec<Option<()>>> = None;
 		let mut holding_cell_held_htlc_flags_opt: Option<Vec<Option<()>>> = None;
+		let mut pending_outbound_accountable_opt: Option<Vec<Option<u8>>> = None;
+		let mut holding_cell_accountable_opt: Option<Vec<Option<u8>>> = None;
 
 		read_tlv_fields!(reader, {
 			(0, announcement_sigs, option),
@@ -15186,6 +15208,8 @@ where
 			(65, quiescent_action, upgradable_option), // Added in 0.2
 			(67, pending_outbound_held_htlc_flags_opt, optional_vec), // Added in 0.2
 			(69, holding_cell_held_htlc_flags_opt, optional_vec), // Added in 0.2
+			(71, holding_cell_accountable_opt, optional_vec), // Added in 0.3
+			(73, pending_outbound_accountable_opt, optional_vec), // Added in 0.3
 		});
 
 		let holder_signer = signer_provider.derive_channel_signer(channel_keys_id);
@@ -15310,6 +15334,28 @@ where
 			}
 		}
 
+		if let Some(accountable_htlcs) = holding_cell_accountable_opt {
+			let mut iter = accountable_htlcs.into_iter();
+			for htlc in holding_cell_htlc_updates.iter_mut() {
+				if let HTLCUpdateAwaitingACK::AddHTLC { ref mut accountable, .. } = htlc {
+					*accountable = iter.next().ok_or(DecodeError::InvalidValue)?;
+				}
+			}
+			// We expect all accountable HTLC signals to be consumed above
+			if iter.next().is_some() {
+				return Err(DecodeError::InvalidValue);
+			}
+		}
+		if let Some(held_htlcs) = pending_outbound_accountable_opt {
+			let mut iter = held_htlcs.into_iter();
+			for htlc in pending_outbound_htlcs.iter_mut() {
+				htlc.accountable = iter.next().ok_or(DecodeError::InvalidValue)?;
+			}
+			// We expect all accountable HTLC signals to be consumed above
+			if iter.next().is_some() {
+				return Err(DecodeError::InvalidValue);
+			}
+		}
 		if let Some(attribution_data_list) = removed_htlc_attribution_data {
 			let mut removed_htlcs = pending_inbound_htlcs.iter_mut().filter_map(|status| {
 				if let InboundHTLCState::LocalRemoved(reason) = &mut status.state {
@@ -15891,6 +15937,7 @@ mod tests {
 			blinding_point: None,
 			send_timestamp: None,
 			hold_htlc: None,
+			accountable: None,
 		});
 
 		// Make sure when Node A calculates their local commitment transaction, none of the HTLCs pass
@@ -16346,6 +16393,7 @@ mod tests {
 			blinding_point: None,
 			send_timestamp: None,
 			hold_htlc: None,
+			accountable: None,
 		};
 		let mut pending_outbound_htlcs = vec![dummy_outbound_output.clone(); 10];
 		for (idx, htlc) in pending_outbound_htlcs.iter_mut().enumerate() {
@@ -16372,6 +16420,7 @@ mod tests {
 			skimmed_fee_msat: None,
 			blinding_point: None,
 			hold_htlc: None,
+			accountable: None,
 		};
 		let dummy_holding_cell_claim_htlc = |attribution_data| HTLCUpdateAwaitingACK::ClaimHTLC {
 			payment_preimage: PaymentPreimage([42; 32]),
@@ -16697,6 +16746,7 @@ mod tests {
 				blinding_point: None,
 				send_timestamp: None,
 				hold_htlc: None,
+				accountable: None,
 			};
 			out.payment_hash.0 = Sha256::hash(&<Vec<u8>>::from_hex("0202020202020202020202020202020202020202020202020202020202020202").unwrap()).to_byte_array();
 			out
@@ -16713,6 +16763,7 @@ mod tests {
 				blinding_point: None,
 				send_timestamp: None,
 				hold_htlc: None,
+				accountable: None,
 			};
 			out.payment_hash.0 = Sha256::hash(&<Vec<u8>>::from_hex("0303030303030303030303030303030303030303030303030303030303030303").unwrap()).to_byte_array();
 			out
@@ -17127,6 +17178,7 @@ mod tests {
 				blinding_point: None,
 				send_timestamp: None,
 				hold_htlc: None,
+				accountable: None,
 			};
 			out.payment_hash.0 = Sha256::hash(&<Vec<u8>>::from_hex("0505050505050505050505050505050505050505050505050505050505050505").unwrap()).to_byte_array();
 			out
@@ -17143,6 +17195,7 @@ mod tests {
 				blinding_point: None,
 				send_timestamp: None,
 				hold_htlc: None,
+				accountable: None,
 			};
 			out.payment_hash.0 = Sha256::hash(&<Vec<u8>>::from_hex("0505050505050505050505050505050505050505050505050505050505050505").unwrap()).to_byte_array();
 			out

lightning/src/ln/channelmanager.rs

@@ -429,6 +429,9 @@ pub struct PendingHTLCInfo {
 	/// This is used to allow LSPs to take fees as a part of payments, without the sender having to
 	/// shoulder them.
 	pub skimmed_fee_msat: Option<u64>,
+	/// An experimental field indicating whether our node's reputation would be held accountable
+	/// for the timely resolution of the received HTLC.
+	pub incoming_accountable: Option<u8>,
 }
 
 #[derive(Clone)] // See FundedChannel::revoke_and_ack for why, tl;dr: Rust bug
@@ -5110,7 +5113,7 @@ where
 				let current_height: u32 = self.best_block.read().unwrap().height;
 				create_recv_pending_htlc_info(decoded_hop, shared_secret, msg.payment_hash,
 					msg.amount_msat, msg.cltv_expiry, None, allow_underpay, msg.skimmed_fee_msat,
-					current_height)
+					msg.accountable, current_height)
 			},
 			onion_utils::Hop::Forward { .. } | onion_utils::Hop::BlindedForward { .. } => {
 				create_fwd_pending_htlc_info(msg, decoded_hop, shared_secret, next_packet_pubkey_opt)
@@ -5330,6 +5333,7 @@ where
 							onion_packet,
 							None,
 							hold_htlc_at_next_hop,
+							Some(0),
 							&self.fee_estimator,
 							&&logger,
 						);
@@ -7212,6 +7216,7 @@ where
 								payment_hash,
 								outgoing_amt_msat,
 								outgoing_cltv_value,
+								incoming_accountable,
 								..
 							},
 					} = payment;
@@ -7310,6 +7315,7 @@ where
 								Some(phantom_shared_secret),
 								false,
 								None,
+								incoming_accountable,
 								current_height,
 							);
 							match create_res {
@@ -7419,6 +7425,7 @@ where
 								outgoing_cltv_value,
 								routing,
 								skimmed_fee_msat,
+								incoming_accountable,
 								..
 							},
 						..
@@ -7514,6 +7521,7 @@ where
 						onion_packet.clone(),
 						*skimmed_fee_msat,
 						next_blinding_point,
+						incoming_accountable.or(Some(0)),
 						&self.fee_estimator,
 						&&logger,
 					) {
@@ -15833,6 +15841,7 @@ impl_writeable_tlv_based!(PendingHTLCInfo, {
 	(8, outgoing_cltv_value, required),
 	(9, incoming_amt_msat, option),
 	(10, skimmed_fee_msat, option),
+	(11, incoming_accountable, option),
 });
 
 impl Writeable for HTLCFailureMsg {
@@ -19268,7 +19277,7 @@ mod tests {
 		if let Err(crate::ln::channelmanager::InboundHTLCErr { reason, .. }) =
 			create_recv_pending_htlc_info(hop_data, [0; 32], PaymentHash([0; 32]),
 				sender_intended_amt_msat - extra_fee_msat - 1, 42, None, true, Some(extra_fee_msat),
-				current_height)
+				None, current_height)
 		{
 			assert_eq!(reason, LocalHTLCFailureReason::FinalIncorrectHTLCAmount);
 		} else { panic!(); }
@@ -19291,7 +19300,7 @@ mod tests {
 		let current_height: u32 = node[0].node.best_block.read().unwrap().height;
 		assert!(create_recv_pending_htlc_info(hop_data, [0; 32], PaymentHash([0; 32]),
 			sender_intended_amt_msat - extra_fee_msat, 42, None, true, Some(extra_fee_msat),
-			current_height).is_ok());
+			None, current_height).is_ok());
 	}
 
 	#[test]
@@ -19316,7 +19325,7 @@ mod tests {
 				custom_tlvs: Vec::new(),
 			},
 			shared_secret: SharedSecret::from_bytes([0; 32]),
-		}, [0; 32], PaymentHash([0; 32]), 100, TEST_FINAL_CLTV + 1, None, true, None, current_height);
+		}, [0; 32], PaymentHash([0; 32]), 100, TEST_FINAL_CLTV + 1, None, true, None, None, current_height);
 
 		// Should not return an error as this condition:
 		// https://github.com/lightning/bolts/blob/4dcc377209509b13cf89a4b91fde7d478f5b46d8/04-onion-routing.md?plain=1#L334

lightning/src/ln/functional_tests.rs

@@ -2269,6 +2269,7 @@ 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);
 	}