fix holding cell persistence for attribution_data

Author: joostjager

lightning/src/ln/channel.rs

@@ -10036,11 +10036,11 @@ 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<&Option<[u8; ATTRIBUTION_DATA_LEN]>> = 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,
@@ -10065,7 +10065,13 @@ impl<SP: Deref> Writeable for FundedChannel<SP> where SP::Target: SignerProvider
 					2u8.write(writer)?;
 					htlc_id.write(writer)?;
 					err_packet.data.write(writer)?;
-					holding_cell_failure_attribution_data.push(&err_packet.attribution_data);
+
+					// 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
@@ -10563,7 +10569,7 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
 		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<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;
@@ -10722,20 +10728,17 @@ impl<'a, 'b, 'c, ES: Deref, SP: Deref> ReadableArgs<(&'a ES, &'b SP, u32, &'c Ch
 			}
 			if removed_htlc_relay_failures.next().is_some() { return Err(DecodeError::InvalidValue); }
 		}
+
 		if let Some(attribution_datas) = holding_cell_failure_attribution_data {
-			let mut holding_cell_failures =
-				holding_cell_htlc_updates.iter_mut().filter_map(|upd|
-					if let HTLCUpdateAwaitingACK::FailHTLC { err_packet: OnionErrorPacket { ref mut attribution_data, .. }, .. } = upd {
-						Some(attribution_data)
-					} else {
-						None
-					}
-				);
+			for (i, attribution_data) in attribution_datas {
+				let update = holding_cell_htlc_updates.get_mut(i as usize).ok_or(DecodeError::InvalidValue)?;
 
-			for attribution_data in attribution_datas {
-				*holding_cell_failures.next().ok_or(DecodeError::InvalidValue)? = attribution_data;
+				if let HTLCUpdateAwaitingACK::FailHTLC { htlc_id: _, ref mut err_packet } = update {
+					err_packet.attribution_data = Some(attribution_data);
+				} else {
+					return Err(DecodeError::InvalidValue);
+				}
 			}
-			if holding_cell_failures.next().is_some() { return Err(DecodeError::InvalidValue); }
 		}
 
 		if let Some(malformed_htlcs) = malformed_htlcs {
@@ -11568,7 +11571,7 @@ mod tests {
 			htlc_id: 0,
 		};
 		let dummy_holding_cell_failed_htlc = |htlc_id| HTLCUpdateAwaitingACK::FailHTLC {
-			htlc_id, err_packet: msgs::OnionErrorPacket { data: vec![42], attribution_data: Some([0; ATTRIBUTION_DATA_LEN]) }
+			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],