Attributable failures

Author: joostjager

lightning/src/ln/channel.rs

@@ -50,7 +50,7 @@ use crate::ln::chan_utils::{
 #[cfg(splicing)]
 use crate::ln::chan_utils::FUNDING_TRANSACTION_WITNESS_WEIGHT;
 use crate::ln::chan_utils;
-use crate::ln::onion_utils::{HTLCFailReason};
+use crate::ln::onion_utils::{HTLCFailReason, ATTRIBUTION_DATA_LEN};
 use crate::chain::BestBlock;
 use crate::chain::chaininterface::{FeeEstimator, ConfirmationTarget, LowerBoundedFeeEstimator, fee_for_weight};
 use crate::chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateStep, LATENCY_GRACE_PERIOD_BLOCKS};
@@ -68,6 +68,7 @@ use crate::util::scid_utils::scid_from_parts;
 
 use crate::io;
 use crate::prelude::*;
+use core::time::Duration;
 use core::{cmp,mem,fmt};
 use core::ops::Deref;
 #[cfg(any(test, fuzzing, debug_assertions))]
@@ -323,6 +324,7 @@ struct OutboundHTLCOutput {
 	source: HTLCSource,
 	blinding_point: Option<PublicKey>,
 	skimmed_fee_msat: Option<u64>,
+	timestamp: Option<Duration>,
 }
 
 /// See AwaitingRemoteRevoke ChannelState for more info
@@ -4933,7 +4935,7 @@ trait FailHTLCContents {
 impl FailHTLCContents for msgs::OnionErrorPacket {
 	type Message = msgs::UpdateFailHTLC;
 	fn to_message(self, htlc_id: u64, channel_id: ChannelId) -> Self::Message {
-		msgs::UpdateFailHTLC { htlc_id, channel_id, reason: self.data }
+		msgs::UpdateFailHTLC { htlc_id, channel_id, reason: self.data, attribution_data: self.attribution_data }
 	}
 	fn to_inbound_htlc_state(self) -> InboundHTLCState {
 		InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(self))
@@ -6100,10 +6102,16 @@ impl<SP: Deref> FundedChannel<SP> where
 					false
 				} else { true }
 			});
+			let now = duration_since_epoch();
 			pending_outbound_htlcs.retain(|htlc| {
 				if let &OutboundHTLCState::AwaitingRemovedRemoteRevoke(ref outcome) = &htlc.state {
 					log_trace!(logger, " ...removing outbound AwaitingRemovedRemoteRevoke {}", &htlc.payment_hash);
-					if let OutboundHTLCOutcome::Failure(reason) = outcome.clone() { // We really want take() here, but, again, non-mut ref :(
+					if let OutboundHTLCOutcome::Failure(mut reason) = outcome.clone() { // We really want take() here, but, again, non-mut ref :(
+						if let (Some(timestamp), Some(now)) = (htlc.timestamp, now) {
+							let hold_time = u32::try_from((now - timestamp).as_millis()).unwrap_or(u32::MAX);
+							reason.set_hold_time(hold_time);
+						}
+
 						revoked_htlcs.push((htlc.source.clone(), htlc.payment_hash, reason));
 					} else {
 						finalized_claimed_htlcs.push(htlc.source.clone());
@@ -6845,6 +6853,7 @@ impl<SP: Deref> FundedChannel<SP> where
 							channel_id: self.context.channel_id(),
 							htlc_id: htlc.htlc_id,
 							reason: err_packet.data.clone(),
+							attribution_data: err_packet.attribution_data,
 						});
 					},
 					&InboundHTLCRemovalReason::FailMalformed((ref sha256_of_onion, ref failure_code)) => {
@@ -8671,6 +8680,7 @@ impl<SP: Deref> FundedChannel<SP> where
 			return Ok(None);
 		}
 
+		let timestamp = duration_since_epoch();
 		self.context.pending_outbound_htlcs.push(OutboundHTLCOutput {
 			htlc_id: self.context.next_holder_htlc_id,
 			amount_msat,
@@ -8680,6 +8690,7 @@ impl<SP: Deref> FundedChannel<SP> where
 			source,
 			blinding_point,
 			skimmed_fee_msat,
+			timestamp,
 		});
 
 		let res = msgs::UpdateAddHTLC {
@@ -10247,6 +10258,7 @@ impl<SP: Deref> Writeable for FundedChannel<SP> where SP::Target: SignerProvider
 				dropped_inbound_htlcs += 1;
 			}
 		}
+		let mut removed_htlc_failure_attribution_data: Vec<&Option<[u8; ATTRIBUTION_DATA_LEN]>> = Vec::new();
 		(self.context.pending_inbound_htlcs.len() as u64 - dropped_inbound_htlcs).write(writer)?;
 		for htlc in self.context.pending_inbound_htlcs.iter() {
 			if let &InboundHTLCState::RemoteAnnounced(_) = &htlc.state {
@@ -10272,9 +10284,10 @@ impl<SP: Deref> Writeable for FundedChannel<SP> where SP::Target: SignerProvider
 				&InboundHTLCState::LocalRemoved(ref removal_reason) => {
 					4u8.write(writer)?;
 					match removal_reason {
-						InboundHTLCRemovalReason::FailRelay(msgs::OnionErrorPacket { data }) => {
+						InboundHTLCRemovalReason::FailRelay(msgs::OnionErrorPacket { data, attribution_data }) => {
 							0u8.write(writer)?;
 							data.write(writer)?;
+							removed_htlc_failure_attribution_data.push(&attribution_data);
 						},
 						InboundHTLCRemovalReason::FailMalformed((hash, code)) => {
 							1u8.write(writer)?;
@@ -10336,10 +10349,11 @@ impl<SP: Deref> Writeable for FundedChannel<SP> where SP::Target: SignerProvider
 
 		let mut holding_cell_skimmed_fees: Vec<Option<u64>> = Vec::new();
 		let mut holding_cell_blinding_points: Vec<Option<PublicKey>> = Vec::new();
+		let mut holding_cell_failure_attribution_data: Vec<(u32, [u8; ATTRIBUTION_DATA_LEN])> = Vec::new();
 		// Vec of (htlc_id, failure_code, sha256_of_onion)
 		let mut malformed_htlcs: Vec<(u64, u16, [u8; 32])> = Vec::new();
 		(self.context.holding_cell_htlc_updates.len() as u64).write(writer)?;
-		for update in self.context.holding_cell_htlc_updates.iter() {
+		for (i, update) in self.context.holding_cell_htlc_updates.iter().enumerate() {
 			match update {
 				&HTLCUpdateAwaitingACK::AddHTLC {
 					ref amount_msat, ref cltv_expiry, ref payment_hash, ref source, ref onion_routing_packet,
@@ -10364,6 +10378,13 @@ impl<SP: Deref> Writeable for FundedChannel<SP> where SP::Target: SignerProvider
 					2u8.write(writer)?;
 					htlc_id.write(writer)?;
 					err_packet.data.write(writer)?;
+
+					// Store the attribution data for later writing. Include the holding cell htlc update index because
+					// FailMalformedHTLC is stored with the same type 2 and we wouldn't be able to distinguish the two
+					// when reading back in.
+					if let Some(attribution_data ) = err_packet.attribution_data {
+						holding_cell_failure_attribution_data.push((i as u32, attribution_data));
+					}
 				}
 				&HTLCUpdateAwaitingACK::FailMalformedHTLC {
 					htlc_id, failure_code, sha256_of_onion
@@ -10547,6 +10568,8 @@ impl<SP: Deref> Writeable for FundedChannel<SP> where SP::Target: SignerProvider
 			(49, self.context.local_initiated_shutdown, option), // Added in 0.0.122
 			(51, is_manual_broadcast, option), // Added in 0.0.124
 			(53, funding_tx_broadcast_safe_event_emitted, option), // Added in 0.0.124
+			(55, removed_htlc_failure_attribution_data, optional_vec), // Added in 0.2
+			(57, holding_cell_failure_attribution_data, optional_vec), // Added in 0.2
 		});
 
 		Ok(())
@@ -10624,6 +10647,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, &'c Channel
 						let reason = match <u8 as Readable>::read(reader)? {
 							0 => InboundHTLCRemovalReason::FailRelay(msgs::OnionErrorPacket {
 								data: Readable::read(reader)?,
+								attribution_data: None,
 							}),
 							1 => InboundHTLCRemovalReason::FailMalformed(Readable::read(reader)?),
 							2 => InboundHTLCRemovalReason::Fulfill(Readable::read(reader)?),
@@ -10664,6 +10688,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, &'c Channel
 				},
 				skimmed_fee_msat: None,
 				blinding_point: None,
+				timestamp: None,
 			});
 		}
 
@@ -10688,6 +10713,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, &'c Channel
 					htlc_id: Readable::read(reader)?,
 					err_packet: OnionErrorPacket {
 						data: Readable::read(reader)?,
+						attribution_data: None,
 					},
 				},
 				_ => return Err(DecodeError::InvalidValue),
@@ -10831,6 +10857,9 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, &'c Channel
 		let mut pending_outbound_blinding_points_opt: Option<Vec<Option<PublicKey>>> = None;
 		let mut holding_cell_blinding_points_opt: Option<Vec<Option<PublicKey>>> = None;
 
+		let mut removed_htlc_failure_attribution_data: Option<Vec<Option<[u8; ATTRIBUTION_DATA_LEN]>>> = None;
+		let mut holding_cell_failure_attribution_data: Option<Vec<(u32, [u8; ATTRIBUTION_DATA_LEN])>> = None;
+
 		let mut malformed_htlcs: Option<Vec<(u64, u16, [u8; 32])>> = None;
 		let mut monitor_pending_update_adds: Option<Vec<msgs::UpdateAddHTLC>> = None;
 
@@ -10873,6 +10902,8 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, &'c Channel
 			(49, local_initiated_shutdown, option),
 			(51, is_manual_broadcast, option),
 			(53, funding_tx_broadcast_safe_event_emitted, option),
+			(55, removed_htlc_failure_attribution_data, optional_vec),
+			(57, holding_cell_failure_attribution_data, optional_vec),
 		});
 
 		let holder_signer = signer_provider.derive_channel_signer(channel_keys_id);
@@ -10954,6 +10985,38 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, &'c Channel
 			if iter.next().is_some() { return Err(DecodeError::InvalidValue) }
 		}
 
+		if let Some(attribution_datas) = removed_htlc_failure_attribution_data {
+			let mut removed_htlc_relay_failures =
+				pending_inbound_htlcs.iter_mut().filter_map(|status|
+					if let InboundHTLCState::LocalRemoved(ref mut reason) = &mut status.state {
+						if let InboundHTLCRemovalReason::FailRelay(ref mut packet) = reason {
+							Some(&mut packet.attribution_data)
+						} else {
+							None
+						}
+					} else {
+						None
+					}
+				);
+
+			for attribution_data in attribution_datas {
+				*removed_htlc_relay_failures.next().ok_or(DecodeError::InvalidValue)? = attribution_data;
+			}
+			if removed_htlc_relay_failures.next().is_some() { return Err(DecodeError::InvalidValue); }
+		}
+
+		if let Some(attribution_datas) = holding_cell_failure_attribution_data {
+			for (i, attribution_data) in attribution_datas {
+				let update = holding_cell_htlc_updates.get_mut(i as usize).ok_or(DecodeError::InvalidValue)?;
+
+				if let HTLCUpdateAwaitingACK::FailHTLC { htlc_id: _, ref mut err_packet } = update {
+					err_packet.attribution_data = Some(attribution_data);
+				} else {
+					return Err(DecodeError::InvalidValue);
+				}
+			}
+		}
+
 		if let Some(malformed_htlcs) = malformed_htlcs {
 			for (malformed_htlc_id, failure_code, sha256_of_onion) in malformed_htlcs {
 				let htlc_idx = holding_cell_htlc_updates.iter().position(|htlc| {
@@ -11144,6 +11207,18 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, &'c Channel
 	}
 }
 
+fn duration_since_epoch() -> Option<Duration> {
+	#[cfg(not(feature = "std"))]
+	let now = None;
+
+	#[cfg(feature = "std")]
+	let now = Some(std::time::SystemTime::now()
+		.duration_since(std::time::SystemTime::UNIX_EPOCH)
+		.expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH"));
+
+	now
+}
+
 #[cfg(test)]
 mod tests {
 	use std::cmp;
@@ -11157,7 +11232,7 @@ mod tests {
 	use bitcoin::network::Network;
 	#[cfg(splicing)]
 	use bitcoin::Weight;
-	use crate::ln::onion_utils::INVALID_ONION_BLINDING;
+	use crate::ln::onion_utils::{ATTRIBUTION_DATA_LEN, INVALID_ONION_BLINDING};
 	use crate::types::payment::{PaymentHash, PaymentPreimage};
 	use crate::ln::channel_keys::{RevocationKey, RevocationBasepoint};
 	use crate::ln::channelmanager::{self, HTLCSource, PaymentId};
@@ -11378,6 +11453,7 @@ mod tests {
 			},
 			skimmed_fee_msat: None,
 			blinding_point: None,
+			timestamp: None,
 		});
 
 		// Make sure when Node A calculates their local commitment transaction, none of the HTLCs pass
@@ -11762,6 +11838,7 @@ mod tests {
 			source: dummy_htlc_source.clone(),
 			skimmed_fee_msat: None,
 			blinding_point: None,
+			timestamp: None,
 		};
 		let mut pending_outbound_htlcs = vec![dummy_outbound_output.clone(); 10];
 		for (idx, htlc) in pending_outbound_htlcs.iter_mut().enumerate() {
@@ -11793,7 +11870,7 @@ mod tests {
 			htlc_id: 0,
 		};
 		let dummy_holding_cell_failed_htlc = |htlc_id| HTLCUpdateAwaitingACK::FailHTLC {
-			htlc_id, err_packet: msgs::OnionErrorPacket { data: vec![42] }
+			htlc_id, err_packet: msgs::OnionErrorPacket { data: vec![42], attribution_data: Some([1; ATTRIBUTION_DATA_LEN]) }
 		};
 		let dummy_holding_cell_malformed_htlc = |htlc_id| HTLCUpdateAwaitingACK::FailMalformedHTLC {
 			htlc_id, failure_code: INVALID_ONION_BLINDING, sha256_of_onion: [0; 32],

lightning/src/ln/channelmanager.rs

@@ -59,7 +59,7 @@ use crate::types::features::Bolt11InvoiceFeatures;
 use crate::routing::router::{BlindedTail, InFlightHtlcs, Path, Payee, PaymentParameters, RouteParameters, RouteParametersConfig, Router, FixedRouter, Route};
 use crate::ln::onion_payment::{check_incoming_htlc_cltv, create_recv_pending_htlc_info, create_fwd_pending_htlc_info, decode_incoming_update_add_htlc_onion, HopConnector, InboundHTLCErr, NextPacketDetails};
 use crate::ln::msgs;
-use crate::ln::onion_utils;
+use crate::ln::onion_utils::{self};
 use crate::ln::onion_utils::{HTLCFailReason, INVALID_ONION_BLINDING};
 use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, CommitmentUpdate, DecodeError, LightningError, MessageSendEvent};
 #[cfg(test)]
@@ -4476,6 +4476,7 @@ where
 			channel_id: msg.channel_id,
 			htlc_id: msg.htlc_id,
 			reason: failure.data,
+			attribution_data: failure.attribution_data,
 		})
 	}
 
@@ -4501,10 +4502,12 @@ where
 					}
 					let failure = HTLCFailReason::reason($err_code, $data.to_vec())
 						.get_encrypted_failure_packet(&shared_secret, &None);
+
 					return PendingHTLCStatus::Fail(HTLCFailureMsg::Relay(msgs::UpdateFailHTLC {
 						channel_id: msg.channel_id,
 						htlc_id: msg.htlc_id,
 						reason: failure.data,
+						attribution_data: failure.attribution_data,
 					}));
 				}
 			}
@@ -12968,11 +12971,15 @@ impl_writeable_tlv_based!(PendingHTLCInfo, {
 impl Writeable for HTLCFailureMsg {
 	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 		match self {
-			HTLCFailureMsg::Relay(msgs::UpdateFailHTLC { channel_id, htlc_id, reason }) => {
+			HTLCFailureMsg::Relay(msgs::UpdateFailHTLC { channel_id, htlc_id, reason, attribution_data }) => {
 				0u8.write(writer)?;
 				channel_id.write(writer)?;
 				htlc_id.write(writer)?;
 				reason.write(writer)?;
+
+				// This code will only ever be hit for legacy data that is re-serialized. It isn't necessary to try
+				// writing out attribution data, because it can never be present.
+				debug_assert!(attribution_data.is_none());
 			},
 			HTLCFailureMsg::Malformed(msgs::UpdateFailMalformedHTLC {
 				channel_id, htlc_id, sha256_of_onion, failure_code
@@ -12997,6 +13004,7 @@ impl Readable for HTLCFailureMsg {
 					channel_id: Readable::read(reader)?,
 					htlc_id: Readable::read(reader)?,
 					reason: Readable::read(reader)?,
+					attribution_data: None,
 				}))
 			},
 			1 => {
@@ -13227,6 +13235,7 @@ impl Writeable for HTLCForwardInfo {
 				write_tlv_fields!(w, {
 					(0, htlc_id, required),
 					(2, err_packet.data, required),
+					(5, err_packet.attribution_data, option),
 				});
 			},
 			Self::FailMalformedHTLC { htlc_id, failure_code, sha256_of_onion } => {
@@ -13257,8 +13266,12 @@ impl Readable for HTLCForwardInfo {
 					(1, malformed_htlc_failure_code, option),
 					(2, err_packet, required),
 					(3, sha256_of_onion, option),
+					(5, attribution_data, option),
 				});
 				if let Some(failure_code) = malformed_htlc_failure_code {
+					if attribution_data.is_some() {
+						return Err(DecodeError::InvalidValue);
+					}
 					Self::FailMalformedHTLC {
 						htlc_id: _init_tlv_based_struct_field!(htlc_id, required),
 						failure_code,
@@ -13269,6 +13282,7 @@ impl Readable for HTLCForwardInfo {
 						htlc_id: _init_tlv_based_struct_field!(htlc_id, required),
 						err_packet: crate::ln::msgs::OnionErrorPacket {
 							data: _init_tlv_based_struct_field!(err_packet, required),
+							attribution_data: _init_tlv_based_struct_field!(attribution_data, option),
 						},
 					}
 				}
@@ -14954,6 +14968,7 @@ mod tests {
 	use bitcoin::secp256k1::ecdh::SharedSecret;
 	use core::sync::atomic::Ordering;
 	use crate::events::{Event, HTLCDestination, ClosureReason};
+	use crate::ln::onion_utils::ATTRIBUTION_DATA_LEN;
 	use crate::ln::types::ChannelId;
 	use crate::types::payment::{PaymentPreimage, PaymentHash, PaymentSecret};
 	use crate::ln::channelmanager::{create_recv_pending_htlc_info, inbound_payment, ChannelConfigOverrides, HTLCForwardInfo, InterceptId, PaymentId, RecipientOnionFields};
@@ -16276,7 +16291,7 @@ mod tests {
 		let mut nodes = create_network(1, &node_cfg, &chanmgrs);
 
 		let dummy_failed_htlc = |htlc_id| {
-			HTLCForwardInfo::FailHTLC { htlc_id, err_packet: msgs::OnionErrorPacket { data: vec![42] } }
+			HTLCForwardInfo::FailHTLC { htlc_id, err_packet: msgs::OnionErrorPacket { data: vec![42], attribution_data: Some([0; ATTRIBUTION_DATA_LEN]) } }
 		};
 		let dummy_malformed_htlc = |htlc_id| {
 			HTLCForwardInfo::FailMalformedHTLC { htlc_id, failure_code: 0x4000, sha256_of_onion: [0; 32] }

lightning/src/ln/functional_tests.rs

@@ -17,6 +17,7 @@ use crate::chain::chaininterface::LowerBoundedFeeEstimator;
 use crate::chain::channelmonitor;
 use crate::chain::channelmonitor::{Balance, ChannelMonitorUpdateStep, CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS, ANTI_REORG_DELAY, COUNTERPARTY_CLAIMABLE_WITHIN_BLOCKS_PINNABLE};
 use crate::chain::transaction::OutPoint;
+use crate::ln::onion_utils::ATTRIBUTION_DATA_LEN;
 use crate::sign::{ecdsa::EcdsaChannelSigner, EntropySource, OutputSpender, SignerProvider};
 use crate::events::bump_transaction::WalletSource;
 use crate::events::{Event, FundingInfo, PathFailure, PaymentPurpose, ClosureReason, HTLCDestination, PaymentFailureReason};
@@ -7058,6 +7059,7 @@ pub fn test_update_fulfill_htlc_bolt2_update_fail_htlc_before_commitment() {
 		channel_id: chan.2,
 		htlc_id: 0,
 		reason: Vec::new(),
+		attribution_data: Some([0; ATTRIBUTION_DATA_LEN])
 	};
 
 	nodes[0].node.handle_update_fail_htlc(nodes[1].node.get_our_node_id(), &update_msg);