Merge tracking of HTLCs-in-commitment with outbound-HTLCs
authorMatt Corallo <git@bluematt.me>
Fri, 4 Jan 2019 19:37:48 +0000 (14:37 -0500)
committerMatt Corallo <git@bluematt.me>
Sun, 13 Jan 2019 17:59:19 +0000 (12:59 -0500)
This simplifies a few things, deduplicates a some small memory
overhead, and, most importantly, is a first step to fixing
would_broadcast_at_height.

src/ln/channel.rs
src/ln/channelmonitor.rs

index 2d579e970cf514805bf10965e810b93df1cbd137..237ccd840f561a86d89d915bf2c4c635157f37b7 100644 (file)
@@ -747,8 +747,12 @@ impl Channel {
        /// have not yet committed it. Such HTLCs will only be included in transactions which are being
        /// generated by the peer which proposed adding the HTLCs, and thus we need to understand both
        /// which peer generated this transaction and "to whom" this transaction flows.
+       /// Returns (the transaction built, the number of HTLC outputs which were present in the
+       /// transaction, the list of HTLCs which were not ignored when building the transaction).
+       /// Note that below-dust HTLCs are included in the third return value, but not the second, and
+       /// sources are provided only for outbound HTLCs in the third return value.
        #[inline]
-       fn build_commitment_transaction(&self, commitment_number: u64, keys: &TxCreationKeys, local: bool, generated_by_local: bool, feerate_per_kw: u64) -> (Transaction, Vec<HTLCOutputInCommitment>, Vec<(PaymentHash, &HTLCSource, Option<u32>)>) {
+       fn build_commitment_transaction(&self, commitment_number: u64, keys: &TxCreationKeys, local: bool, generated_by_local: bool, feerate_per_kw: u64) -> (Transaction, usize, Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)>) {
                let obscured_commitment_transaction_number = self.get_commitment_transaction_number_obscure_factor() ^ (INITIAL_COMMITMENT_NUMBER - commitment_number);
 
                let txins = {
@@ -915,30 +919,23 @@ impl Channel {
                transaction_utils::sort_outputs(&mut txouts);
 
                let mut outputs: Vec<TxOut> = Vec::with_capacity(txouts.len());
-               let mut htlcs_included: Vec<HTLCOutputInCommitment> = Vec::with_capacity(txouts.len());
-               let mut htlc_sources: Vec<(PaymentHash, &HTLCSource, Option<u32>)> = Vec::with_capacity(txouts.len() + included_dust_htlcs.len());
-               for (idx, out) in txouts.drain(..).enumerate() {
+               let mut htlcs_included: Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)> = Vec::with_capacity(txouts.len() + included_dust_htlcs.len());
+               for (idx, mut out) in txouts.drain(..).enumerate() {
                        outputs.push(out.0);
-                       if let Some((mut htlc, source_option)) = out.1 {
+                       if let Some((mut htlc, source_option)) = out.1.take() {
                                htlc.transaction_output_index = Some(idx as u32);
-                               if let Some(source) = source_option {
-                                       htlc_sources.push((htlc.payment_hash, source, Some(idx as u32)));
-                               }
-                               htlcs_included.push(htlc);
-                       }
-               }
-               for (htlc, source_option) in included_dust_htlcs.drain(..) {
-                       if let Some(source) = source_option {
-                               htlc_sources.push((htlc.payment_hash, source, None));
+                               htlcs_included.push((htlc, source_option));
                        }
                }
+               let non_dust_htlc_count = htlcs_included.len();
+               htlcs_included.append(&mut included_dust_htlcs);
 
                (Transaction {
                        version: 2,
                        lock_time: ((0x20 as u32) << 8*3) | ((obscured_commitment_transaction_number & 0xffffffu64) as u32),
                        input: txins,
                        output: outputs,
-               }, htlcs_included, htlc_sources)
+               }, non_dust_htlc_count, htlcs_included)
        }
 
        #[inline]
@@ -1451,9 +1448,9 @@ impl Channel {
 
                // Now that we're past error-generating stuff, update our local state:
 
-               self.channel_monitor.provide_latest_remote_commitment_tx_info(&remote_initial_commitment_tx, Vec::new(), Vec::new(), self.cur_remote_commitment_transaction_number, self.their_cur_commitment_point.unwrap());
+               self.channel_monitor.provide_latest_remote_commitment_tx_info(&remote_initial_commitment_tx, Vec::new(), self.cur_remote_commitment_transaction_number, self.their_cur_commitment_point.unwrap());
                self.last_local_commitment_txn = vec![local_initial_commitment_tx.clone()];
-               self.channel_monitor.provide_latest_local_commitment_tx_info(local_initial_commitment_tx, local_keys, self.feerate_per_kw, Vec::new(), Vec::new());
+               self.channel_monitor.provide_latest_local_commitment_tx_info(local_initial_commitment_tx, local_keys, self.feerate_per_kw, Vec::new());
                self.channel_state = ChannelState::FundingSent as u32;
                self.channel_id = funding_txo.to_channel_id();
                self.cur_remote_commitment_transaction_number -= 1;
@@ -1490,7 +1487,7 @@ impl Channel {
                secp_check!(self.secp_ctx.verify(&local_sighash, &msg.signature, &self.their_funding_pubkey.unwrap()), "Invalid funding_signed signature from peer");
 
                self.sign_commitment_transaction(&mut local_initial_commitment_tx, &msg.signature);
-               self.channel_monitor.provide_latest_local_commitment_tx_info(local_initial_commitment_tx.clone(), local_keys, self.feerate_per_kw, Vec::new(), Vec::new());
+               self.channel_monitor.provide_latest_local_commitment_tx_info(local_initial_commitment_tx.clone(), local_keys, self.feerate_per_kw, Vec::new());
                self.last_local_commitment_txn = vec![local_initial_commitment_tx];
                self.channel_state = ChannelState::FundingSent as u32;
                self.cur_local_commitment_transaction_number -= 1;
@@ -1693,7 +1690,7 @@ impl Channel {
 
                let mut local_commitment_tx = {
                        let mut commitment_tx = self.build_commitment_transaction(self.cur_local_commitment_transaction_number, &local_keys, true, false, feerate_per_kw);
-                       let htlcs_cloned: Vec<_> = commitment_tx.2.drain(..).map(|htlc_source| (htlc_source.0, htlc_source.1.clone(), htlc_source.2)).collect();
+                       let htlcs_cloned: Vec<_> = commitment_tx.2.drain(..).map(|htlc| (htlc.0, htlc.1.map(|h| h.clone()))).collect();
                        (commitment_tx.0, commitment_tx.1, htlcs_cloned)
                };
                let local_commitment_txid = local_commitment_tx.0.txid();
@@ -1702,7 +1699,7 @@ impl Channel {
 
                //If channel fee was updated by funder confirm funder can afford the new fee rate when applied to the current local commitment transaction
                if update_fee {
-                       let num_htlcs = local_commitment_tx.1.len();
+                       let num_htlcs = local_commitment_tx.1;
                        let total_fee: u64 = feerate_per_kw as u64 * (COMMITMENT_TX_BASE_WEIGHT + (num_htlcs as u64) * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000;
 
                        if self.channel_value_satoshis - self.value_to_self_msat / 1000 < total_fee + self.their_channel_reserve_satoshis {
@@ -1710,16 +1707,16 @@ impl Channel {
                        }
                }
 
-               if msg.htlc_signatures.len() != local_commitment_tx.1.len() {
+               if msg.htlc_signatures.len() != local_commitment_tx.1 {
                        return Err(ChannelError::Close("Got wrong number of HTLC signatures from remote"));
                }
 
-               let mut new_local_commitment_txn = Vec::with_capacity(local_commitment_tx.1.len() + 1);
+               let mut new_local_commitment_txn = Vec::with_capacity(local_commitment_tx.1 + 1);
                self.sign_commitment_transaction(&mut local_commitment_tx.0, &msg.signature);
                new_local_commitment_txn.push(local_commitment_tx.0.clone());
 
-               let mut htlcs_and_sigs = Vec::with_capacity(local_commitment_tx.1.len());
-               for (idx, htlc) in local_commitment_tx.1.drain(..).enumerate() {
+               let mut htlcs_and_sigs = Vec::with_capacity(local_commitment_tx.2.len());
+               for (idx, (htlc, source)) in local_commitment_tx.2.drain(..).enumerate() {
                        if let Some(_) = htlc.transaction_output_index {
                                let mut htlc_tx = self.build_htlc_transaction(&local_commitment_txid, &htlc, true, &local_keys, feerate_per_kw);
                                let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &local_keys);
@@ -1732,7 +1729,9 @@ impl Channel {
                                } else {
                                        self.create_htlc_tx_signature(&htlc_tx, &htlc, &local_keys)?.1
                                };
-                               htlcs_and_sigs.push((htlc, msg.htlc_signatures[idx], htlc_sig));
+                               htlcs_and_sigs.push((htlc, Some((msg.htlc_signatures[idx], htlc_sig)), source));
+                       } else {
+                               htlcs_and_sigs.push((htlc, None, source));
                        }
                }
 
@@ -1760,7 +1759,7 @@ impl Channel {
                        self.monitor_pending_order = None;
                }
 
-               self.channel_monitor.provide_latest_local_commitment_tx_info(local_commitment_tx.0, local_keys, self.feerate_per_kw, htlcs_and_sigs, local_commitment_tx.2);
+               self.channel_monitor.provide_latest_local_commitment_tx_info(local_commitment_tx.0, local_keys, self.feerate_per_kw, htlcs_and_sigs);
 
                for htlc in self.pending_inbound_htlcs.iter_mut() {
                        let new_forward = if let &InboundHTLCState::RemoteAnnounced(ref forward_info) = &htlc.state {
@@ -3030,7 +3029,7 @@ impl Channel {
                let temporary_channel_id = self.channel_id;
 
                // Now that we're past error-generating stuff, update our local state:
-               self.channel_monitor.provide_latest_remote_commitment_tx_info(&commitment_tx, Vec::new(), Vec::new(), self.cur_remote_commitment_transaction_number, self.their_cur_commitment_point.unwrap());
+               self.channel_monitor.provide_latest_remote_commitment_tx_info(&commitment_tx, Vec::new(), self.cur_remote_commitment_transaction_number, self.their_cur_commitment_point.unwrap());
                self.channel_state = ChannelState::FundingCreated as u32;
                self.channel_id = funding_txo.to_channel_id();
                self.cur_remote_commitment_transaction_number -= 1;
@@ -3262,23 +3261,23 @@ impl Channel {
                        }
                }
 
-               let (res, remote_commitment_tx, htlcs, htlc_sources) = match self.send_commitment_no_state_update() {
-                       Ok((res, (remote_commitment_tx, htlcs, mut htlc_sources))) => {
+               let (res, remote_commitment_tx, htlcs) = match self.send_commitment_no_state_update() {
+                       Ok((res, (remote_commitment_tx, mut htlcs))) => {
                                // Update state now that we've passed all the can-fail calls...
-                               let htlc_sources_no_ref = htlc_sources.drain(..).map(|htlc_source| (htlc_source.0, htlc_source.1.clone(), htlc_source.2)).collect();
-                               (res, remote_commitment_tx, htlcs, htlc_sources_no_ref)
+                               let htlcs_no_ref = htlcs.drain(..).map(|(htlc, htlc_source)| (htlc, htlc_source.map(|source_ref| Box::new(source_ref.clone())))).collect();
+                               (res, remote_commitment_tx, htlcs_no_ref)
                        },
                        Err(e) => return Err(e),
                };
 
-               self.channel_monitor.provide_latest_remote_commitment_tx_info(&remote_commitment_tx, htlcs, htlc_sources, self.cur_remote_commitment_transaction_number, self.their_cur_commitment_point.unwrap());
+               self.channel_monitor.provide_latest_remote_commitment_tx_info(&remote_commitment_tx, htlcs, self.cur_remote_commitment_transaction_number, self.their_cur_commitment_point.unwrap());
                self.channel_state |= ChannelState::AwaitingRemoteRevoke as u32;
                Ok((res, self.channel_monitor.clone()))
        }
 
        /// Only fails in case of bad keys. Used for channel_reestablish commitment_signed generation
        /// when we shouldn't change HTLC/channel state.
-       fn send_commitment_no_state_update(&self) -> Result<(msgs::CommitmentSigned, (Transaction, Vec<HTLCOutputInCommitment>, Vec<(PaymentHash, &HTLCSource, Option<u32>)>)), ChannelError> {
+       fn send_commitment_no_state_update(&self) -> Result<(msgs::CommitmentSigned, (Transaction, Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)>)), ChannelError> {
                let funding_script = self.get_funding_redeemscript();
 
                let mut feerate_per_kw = self.feerate_per_kw;
@@ -3294,9 +3293,8 @@ impl Channel {
                let remote_sighash = Message::from_slice(&bip143::SighashComponents::new(&remote_commitment_tx.0).sighash_all(&remote_commitment_tx.0.input[0], &funding_script, self.channel_value_satoshis)[..]).unwrap();
                let our_sig = self.secp_ctx.sign(&remote_sighash, &self.local_keys.funding_key);
 
-               let mut htlc_sigs = Vec::new();
-
-               for ref htlc in remote_commitment_tx.1.iter() {
+               let mut htlc_sigs = Vec::with_capacity(remote_commitment_tx.1);
+               for &(ref htlc, _) in remote_commitment_tx.2.iter() {
                        if let Some(_) = htlc.transaction_output_index {
                                let htlc_tx = self.build_htlc_transaction(&remote_commitment_txid, htlc, false, &remote_keys, feerate_per_kw);
                                let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &remote_keys);
@@ -3310,7 +3308,7 @@ impl Channel {
                        channel_id: self.channel_id,
                        signature: our_sig,
                        htlc_signatures: htlc_sigs,
-               }, remote_commitment_tx))
+               }, (remote_commitment_tx.0, remote_commitment_tx.2)))
        }
 
        /// Adds a pending outbound HTLC to this channel, and creates a signed commitment transaction
@@ -4024,8 +4022,11 @@ mod tests {
                macro_rules! test_commitment {
                        ( $their_sig_hex: expr, $our_sig_hex: expr, $tx_hex: expr) => {
                                unsigned_tx = {
-                                       let res = chan.build_commitment_transaction(0xffffffffffff - 42, &keys, true, false, chan.feerate_per_kw);
-                                       (res.0, res.1)
+                                       let mut res = chan.build_commitment_transaction(0xffffffffffff - 42, &keys, true, false, chan.feerate_per_kw);
+                                       let htlcs = res.2.drain(..)
+                                               .filter_map(|(htlc, _)| if htlc.transaction_output_index.is_some() { Some(htlc) } else { None })
+                                               .collect();
+                                       (res.0, htlcs)
                                };
                                let their_signature = Signature::from_der(&secp_ctx, &hex::decode($their_sig_hex).unwrap()[..]).unwrap();
                                let sighash = Message::from_slice(&bip143::SighashComponents::new(&unsigned_tx.0).sighash_all(&unsigned_tx.0.input[0], &chan.get_funding_redeemscript(), chan.channel_value_satoshis)[..]).unwrap();
index 04efd0a8d940d8824f357e68d38613962cdc52df..c1c24f5faf6bb0d3425e24965ff67064dcd018fa 100644 (file)
@@ -332,8 +332,7 @@ struct LocalSignedTx {
        b_htlc_key: PublicKey,
        delayed_payment_key: PublicKey,
        feerate_per_kw: u64,
-       htlc_outputs: Vec<(HTLCOutputInCommitment, Signature, Signature)>,
-       htlc_sources: Vec<(PaymentHash, HTLCSource, Option<u32>)>,
+       htlc_outputs: Vec<(HTLCOutputInCommitment, Option<(Signature, Signature)>, Option<HTLCSource>)>,
 }
 
 const SERIALIZATION_VERSION: u8 = 1;
@@ -358,7 +357,7 @@ pub struct ChannelMonitor {
        their_to_self_delay: Option<u16>,
 
        old_secrets: [([u8; 32], u64); 49],
-       remote_claimable_outpoints: HashMap<Sha256dHash, (Vec<HTLCOutputInCommitment>, Vec<(PaymentHash, HTLCSource, Option<u32>)>)>,
+       remote_claimable_outpoints: HashMap<Sha256dHash, Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>>,
        /// We cannot identify HTLC-Success or HTLC-Timeout transactions by themselves on the chain.
        /// Nor can we figure out their commitment numbers without the commitment transaction they are
        /// spending. Thus, in order to claim them via revocation key, we track all the remote
@@ -515,7 +514,9 @@ impl ChannelMonitor {
                // TODO: We should probably consider whether we're really getting the next secret here.
                if let Storage::Local { ref mut prev_remote_commitment_txid, .. } = self.key_storage {
                        if let Some(txid) = prev_remote_commitment_txid.take() {
-                               self.remote_claimable_outpoints.get_mut(&txid).unwrap().1 = Vec::new();
+                               for &mut (_, ref mut source) in self.remote_claimable_outpoints.get_mut(&txid).unwrap() {
+                                       *source = None;
+                               }
                        }
                }
 
@@ -558,12 +559,12 @@ impl ChannelMonitor {
        /// The monitor watches for it to be broadcasted and then uses the HTLC information (and
        /// possibly future revocation/preimage information) to claim outputs where possible.
        /// We cache also the mapping hash:commitment number to lighten pruning of old preimages by watchtowers.
-       pub(super) fn provide_latest_remote_commitment_tx_info(&mut self, unsigned_commitment_tx: &Transaction, htlc_outputs: Vec<HTLCOutputInCommitment>, htlc_sources: Vec<(PaymentHash, HTLCSource, Option<u32>)>, commitment_number: u64, their_revocation_point: PublicKey) {
+       pub(super) fn provide_latest_remote_commitment_tx_info(&mut self, unsigned_commitment_tx: &Transaction, htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Box<HTLCSource>>)>, commitment_number: u64, their_revocation_point: PublicKey) {
                // TODO: Encrypt the htlc_outputs data with the single-hash of the commitment transaction
                // so that a remote monitor doesn't learn anything unless there is a malicious close.
                // (only maybe, sadly we cant do the same for local info, as we need to be aware of
                // timeouts)
-               for ref htlc in &htlc_outputs {
+               for &(ref htlc, _) in &htlc_outputs {
                        self.remote_hash_commitment_number.insert(htlc.payment_hash, commitment_number);
                }
 
@@ -574,7 +575,7 @@ impl ChannelMonitor {
                        *prev_remote_commitment_txid = current_remote_commitment_txid.take();
                        *current_remote_commitment_txid = Some(new_txid);
                }
-               self.remote_claimable_outpoints.insert(new_txid, (htlc_outputs, htlc_sources));
+               self.remote_claimable_outpoints.insert(new_txid, htlc_outputs);
                self.current_remote_commitment_number = commitment_number;
                //TODO: Merge this into the other per-remote-transaction output storage stuff
                match self.their_cur_revocation_points {
@@ -604,7 +605,7 @@ impl ChannelMonitor {
        /// Panics if set_their_to_self_delay has never been called.
        /// Also update Storage with latest local per_commitment_point to derive local_delayedkey in
        /// case of onchain HTLC tx
-       pub(super) fn provide_latest_local_commitment_tx_info(&mut self, signed_commitment_tx: Transaction, local_keys: chan_utils::TxCreationKeys, feerate_per_kw: u64, htlc_outputs: Vec<(HTLCOutputInCommitment, Signature, Signature)>, htlc_sources: Vec<(PaymentHash, HTLCSource, Option<u32>)>) {
+       pub(super) fn provide_latest_local_commitment_tx_info(&mut self, signed_commitment_tx: Transaction, local_keys: chan_utils::TxCreationKeys, feerate_per_kw: u64, htlc_outputs: Vec<(HTLCOutputInCommitment, Option<(Signature, Signature)>, Option<HTLCSource>)>) {
                assert!(self.their_to_self_delay.is_some());
                self.prev_local_signed_commitment_tx = self.current_local_signed_commitment_tx.take();
                self.current_local_signed_commitment_tx = Some(LocalSignedTx {
@@ -616,7 +617,6 @@ impl ChannelMonitor {
                        delayed_payment_key: local_keys.a_delayed_payment_key,
                        feerate_per_kw,
                        htlc_outputs,
-                       htlc_sources,
                });
 
                if let Storage::Local { ref mut latest_per_commitment_point, .. } = self.key_storage {
@@ -863,30 +863,13 @@ impl ChannelMonitor {
                        }
                }
 
-               macro_rules! serialize_htlc_source {
-                       ($htlc_source: expr) => {
-                               $htlc_source.0.write(writer)?;
-                               $htlc_source.1.write(writer)?;
-                               if let &Some(ref txo) = &$htlc_source.2 {
-                                       writer.write_all(&[1; 1])?;
-                                       txo.write(writer)?;
-                               } else {
-                                       writer.write_all(&[0; 1])?;
-                               }
-                       }
-               }
-
-
                writer.write_all(&byte_utils::be64_to_array(self.remote_claimable_outpoints.len() as u64))?;
-               for (ref txid, &(ref htlc_infos, ref htlc_sources)) in self.remote_claimable_outpoints.iter() {
+               for (ref txid, ref htlc_infos) in self.remote_claimable_outpoints.iter() {
                        writer.write_all(&txid[..])?;
                        writer.write_all(&byte_utils::be64_to_array(htlc_infos.len() as u64))?;
-                       for ref htlc_output in htlc_infos.iter() {
+                       for &(ref htlc_output, ref htlc_source) in htlc_infos.iter() {
                                serialize_htlc_in_commitment!(htlc_output);
-                       }
-                       writer.write_all(&byte_utils::be64_to_array(htlc_sources.len() as u64))?;
-                       for ref htlc_source in htlc_sources.iter() {
-                               serialize_htlc_source!(htlc_source);
+                               write_option!(htlc_source);
                        }
                }
 
@@ -926,14 +909,16 @@ impl ChannelMonitor {
 
                                writer.write_all(&byte_utils::be64_to_array($local_tx.feerate_per_kw))?;
                                writer.write_all(&byte_utils::be64_to_array($local_tx.htlc_outputs.len() as u64))?;
-                               for &(ref htlc_output, ref their_sig, ref our_sig) in $local_tx.htlc_outputs.iter() {
+                               for &(ref htlc_output, ref sigs, ref htlc_source) in $local_tx.htlc_outputs.iter() {
                                        serialize_htlc_in_commitment!(htlc_output);
-                                       writer.write_all(&their_sig.serialize_compact(&self.secp_ctx))?;
-                                       writer.write_all(&our_sig.serialize_compact(&self.secp_ctx))?;
-                               }
-                               writer.write_all(&byte_utils::be64_to_array($local_tx.htlc_sources.len() as u64))?;
-                               for ref htlc_source in $local_tx.htlc_sources.iter() {
-                                       serialize_htlc_source!(htlc_source);
+                                       if let &Some((ref their_sig, ref our_sig)) = sigs {
+                                               1u8.write(writer)?;
+                                               writer.write_all(&their_sig.serialize_compact(&self.secp_ctx))?;
+                                               writer.write_all(&our_sig.serialize_compact(&self.secp_ctx))?;
+                                       } else {
+                                               0u8.write(writer)?;
+                                       }
+                                       write_option!(htlc_source);
                                }
                        }
                }
@@ -1117,7 +1102,7 @@ impl ChannelMonitor {
                                                let (sig, redeemscript) = match self.key_storage {
                                                        Storage::Local { ref revocation_base_key, .. } => {
                                                                let redeemscript = if $htlc_idx.is_none() { revokeable_redeemscript.clone() } else {
-                                                                       let htlc = &per_commitment_option.unwrap().0[$htlc_idx.unwrap()];
+                                                                       let htlc = &per_commitment_option.unwrap()[$htlc_idx.unwrap()].0;
                                                                        chan_utils::get_htlc_redeemscript_with_explicit_keys(htlc, &a_htlc_key, &b_htlc_key, &revocation_pubkey)
                                                                };
                                                                let sighash = ignore_error!(Message::from_slice(&$sighash_parts.sighash_all(&$input, &redeemscript, $amount)[..]));
@@ -1140,10 +1125,10 @@ impl ChannelMonitor {
                                }
                        }
 
-                       if let Some(&(ref per_commitment_data, _)) = per_commitment_option {
+                       if let Some(ref per_commitment_data) = per_commitment_option {
                                inputs.reserve_exact(per_commitment_data.len());
 
-                               for (idx, ref htlc) in per_commitment_data.iter().enumerate() {
+                               for (idx, &(ref htlc, _)) in per_commitment_data.iter().enumerate() {
                                        if let Some(transaction_output_index) = htlc.transaction_output_index {
                                                let expected_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &a_htlc_key, &b_htlc_key, &revocation_pubkey);
                                                if transaction_output_index as usize >= tx.output.len() ||
@@ -1194,10 +1179,12 @@ impl ChannelMonitor {
                                // on-chain claims, so we can do that at the same time.
                                macro_rules! check_htlc_fails {
                                        ($txid: expr, $commitment_tx: expr) => {
-                                               if let Some(&(_, ref outpoints)) = self.remote_claimable_outpoints.get(&$txid) {
-                                                       for &(ref payment_hash, ref source, _) in outpoints.iter() {
-                                                               log_trace!(self, "Failing HTLC with payment_hash {} from {} remote commitment tx due to broadcast of revoked remote commitment transaction", log_bytes!(payment_hash.0), $commitment_tx);
-                                                               htlc_updated.push(((*source).clone(), None, payment_hash.clone()));
+                                               if let Some(ref outpoints) = self.remote_claimable_outpoints.get(&$txid) {
+                                                       for &(ref htlc, ref source_option) in outpoints.iter() {
+                                                               if let &Some(ref source) = source_option {
+                                                                       log_trace!(self, "Failing HTLC with payment_hash {} from {} remote commitment tx due to broadcast of revoked remote commitment transaction", log_bytes!(htlc.payment_hash.0), $commitment_tx);
+                                                                       htlc_updated.push(((**source).clone(), None, htlc.payment_hash.clone()));
+                                                               }
                                                        }
                                                }
                                        }
@@ -1256,24 +1243,26 @@ impl ChannelMonitor {
                        // on-chain claims, so we can do that at the same time.
                        macro_rules! check_htlc_fails {
                                ($txid: expr, $commitment_tx: expr, $id: tt) => {
-                                       if let Some(&(_, ref latest_outpoints)) = self.remote_claimable_outpoints.get(&$txid) {
-                                               $id: for &(ref payment_hash, ref source, _) in latest_outpoints.iter() {
-                                                       // Check if the HTLC is present in the commitment transaction that was
-                                                       // broadcast, but not if it was below the dust limit, which we should
-                                                       // fail backwards immediately as there is no way for us to learn the
-                                                       // payment_preimage.
-                                                       // Note that if the dust limit were allowed to change between
-                                                       // commitment transactions we'd want to be check whether *any*
-                                                       // broadcastable commitment transaction has the HTLC in it, but it
-                                                       // cannot currently change after channel initialization, so we don't
-                                                       // need to here.
-                                                       for &(_, ref broadcast_source, ref output_idx) in per_commitment_data.1.iter() {
-                                                               if output_idx.is_some() && source == broadcast_source {
-                                                                       continue $id;
+                                       if let Some(ref latest_outpoints) = self.remote_claimable_outpoints.get(&$txid) {
+                                               $id: for &(ref htlc, ref source_option) in latest_outpoints.iter() {
+                                                       if let &Some(ref source) = source_option {
+                                                               // Check if the HTLC is present in the commitment transaction that was
+                                                               // broadcast, but not if it was below the dust limit, which we should
+                                                               // fail backwards immediately as there is no way for us to learn the
+                                                               // payment_preimage.
+                                                               // Note that if the dust limit were allowed to change between
+                                                               // commitment transactions we'd want to be check whether *any*
+                                                               // broadcastable commitment transaction has the HTLC in it, but it
+                                                               // cannot currently change after channel initialization, so we don't
+                                                               // need to here.
+                                                               for &(ref broadcast_htlc, ref broadcast_source) in per_commitment_data.iter() {
+                                                                       if broadcast_htlc.transaction_output_index.is_some() && Some(source) == broadcast_source.as_ref() {
+                                                                               continue $id;
+                                                                       }
                                                                }
+                                                               log_trace!(self, "Failing HTLC with payment_hash {} from {} remote commitment tx due to broadcast of remote commitment transaction", log_bytes!(htlc.payment_hash.0), $commitment_tx);
+                                                               htlc_updated.push(((**source).clone(), None, htlc.payment_hash.clone()));
                                                        }
-                                                       log_trace!(self, "Failing HTLC with payment_hash {} from {} remote commitment tx due to broadcast of remote commitment transaction", log_bytes!(payment_hash.0), $commitment_tx);
-                                                       htlc_updated.push(((*source).clone(), None, payment_hash.clone()));
                                                }
                                        }
                                }
@@ -1336,7 +1325,7 @@ impl ChannelMonitor {
                                                        {
                                                                let (sig, redeemscript) = match self.key_storage {
                                                                        Storage::Local { ref htlc_base_key, .. } => {
-                                                                               let htlc = &per_commitment_option.unwrap().0[$input.sequence as usize];
+                                                                               let htlc = &per_commitment_option.unwrap()[$input.sequence as usize].0;
                                                                                let redeemscript = chan_utils::get_htlc_redeemscript_with_explicit_keys(htlc, &a_htlc_key, &b_htlc_key, &revocation_pubkey);
                                                                                let sighash = ignore_error!(Message::from_slice(&$sighash_parts.sighash_all(&$input, &redeemscript, $amount)[..]));
                                                                                let htlc_key = ignore_error!(chan_utils::derive_private_key(&self.secp_ctx, revocation_point, &htlc_base_key));
@@ -1354,7 +1343,7 @@ impl ChannelMonitor {
                                                }
                                        }
 
-                                       for (idx, ref htlc) in per_commitment_data.0.iter().enumerate() {
+                                       for (idx, &(ref htlc, _)) in per_commitment_data.iter().enumerate() {
                                                if let Some(transaction_output_index) = htlc.transaction_output_index {
                                                        let expected_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &a_htlc_key, &b_htlc_key, &revocation_pubkey);
                                                        if transaction_output_index as usize >= tx.output.len() ||
@@ -1575,42 +1564,44 @@ impl ChannelMonitor {
                        }
                }
 
-               for &(ref htlc, ref their_sig, ref our_sig) in local_tx.htlc_outputs.iter() {
+               for &(ref htlc, ref sigs, _) in local_tx.htlc_outputs.iter() {
                        if let Some(transaction_output_index) = htlc.transaction_output_index {
-                               if htlc.offered {
-                                       let mut htlc_timeout_tx = chan_utils::build_htlc_transaction(&local_tx.txid, local_tx.feerate_per_kw, self.their_to_self_delay.unwrap(), htlc, &local_tx.delayed_payment_key, &local_tx.revocation_key);
+                               if let &Some((ref their_sig, ref our_sig)) = sigs {
+                                       if htlc.offered {
+                                               let mut htlc_timeout_tx = chan_utils::build_htlc_transaction(&local_tx.txid, local_tx.feerate_per_kw, self.their_to_self_delay.unwrap(), htlc, &local_tx.delayed_payment_key, &local_tx.revocation_key);
 
-                                       htlc_timeout_tx.input[0].witness.push(Vec::new()); // First is the multisig dummy
+                                               htlc_timeout_tx.input[0].witness.push(Vec::new()); // First is the multisig dummy
 
-                                       htlc_timeout_tx.input[0].witness.push(their_sig.serialize_der(&self.secp_ctx).to_vec());
-                                       htlc_timeout_tx.input[0].witness[1].push(SigHashType::All as u8);
-                                       htlc_timeout_tx.input[0].witness.push(our_sig.serialize_der(&self.secp_ctx).to_vec());
-                                       htlc_timeout_tx.input[0].witness[2].push(SigHashType::All as u8);
+                                               htlc_timeout_tx.input[0].witness.push(their_sig.serialize_der(&self.secp_ctx).to_vec());
+                                               htlc_timeout_tx.input[0].witness[1].push(SigHashType::All as u8);
+                                               htlc_timeout_tx.input[0].witness.push(our_sig.serialize_der(&self.secp_ctx).to_vec());
+                                               htlc_timeout_tx.input[0].witness[2].push(SigHashType::All as u8);
 
-                                       htlc_timeout_tx.input[0].witness.push(Vec::new());
-                                       htlc_timeout_tx.input[0].witness.push(chan_utils::get_htlc_redeemscript_with_explicit_keys(htlc, &local_tx.a_htlc_key, &local_tx.b_htlc_key, &local_tx.revocation_key).into_bytes());
+                                               htlc_timeout_tx.input[0].witness.push(Vec::new());
+                                               htlc_timeout_tx.input[0].witness.push(chan_utils::get_htlc_redeemscript_with_explicit_keys(htlc, &local_tx.a_htlc_key, &local_tx.b_htlc_key, &local_tx.revocation_key).into_bytes());
 
-                                       add_dynamic_output!(htlc_timeout_tx, 0);
-                                       res.push(htlc_timeout_tx);
-                               } else {
-                                       if let Some(payment_preimage) = self.payment_preimages.get(&htlc.payment_hash) {
-                                               let mut htlc_success_tx = chan_utils::build_htlc_transaction(&local_tx.txid, local_tx.feerate_per_kw, self.their_to_self_delay.unwrap(), htlc, &local_tx.delayed_payment_key, &local_tx.revocation_key);
+                                               add_dynamic_output!(htlc_timeout_tx, 0);
+                                               res.push(htlc_timeout_tx);
+                                       } else {
+                                               if let Some(payment_preimage) = self.payment_preimages.get(&htlc.payment_hash) {
+                                                       let mut htlc_success_tx = chan_utils::build_htlc_transaction(&local_tx.txid, local_tx.feerate_per_kw, self.their_to_self_delay.unwrap(), htlc, &local_tx.delayed_payment_key, &local_tx.revocation_key);
 
-                                               htlc_success_tx.input[0].witness.push(Vec::new()); // First is the multisig dummy
+                                                       htlc_success_tx.input[0].witness.push(Vec::new()); // First is the multisig dummy
 
-                                               htlc_success_tx.input[0].witness.push(their_sig.serialize_der(&self.secp_ctx).to_vec());
-                                               htlc_success_tx.input[0].witness[1].push(SigHashType::All as u8);
-                                               htlc_success_tx.input[0].witness.push(our_sig.serialize_der(&self.secp_ctx).to_vec());
-                                               htlc_success_tx.input[0].witness[2].push(SigHashType::All as u8);
+                                                       htlc_success_tx.input[0].witness.push(their_sig.serialize_der(&self.secp_ctx).to_vec());
+                                                       htlc_success_tx.input[0].witness[1].push(SigHashType::All as u8);
+                                                       htlc_success_tx.input[0].witness.push(our_sig.serialize_der(&self.secp_ctx).to_vec());
+                                                       htlc_success_tx.input[0].witness[2].push(SigHashType::All as u8);
 
-                                               htlc_success_tx.input[0].witness.push(payment_preimage.0.to_vec());
-                                               htlc_success_tx.input[0].witness.push(chan_utils::get_htlc_redeemscript_with_explicit_keys(htlc, &local_tx.a_htlc_key, &local_tx.b_htlc_key, &local_tx.revocation_key).into_bytes());
+                                                       htlc_success_tx.input[0].witness.push(payment_preimage.0.to_vec());
+                                                       htlc_success_tx.input[0].witness.push(chan_utils::get_htlc_redeemscript_with_explicit_keys(htlc, &local_tx.a_htlc_key, &local_tx.b_htlc_key, &local_tx.revocation_key).into_bytes());
 
-                                               add_dynamic_output!(htlc_success_tx, 0);
-                                               res.push(htlc_success_tx);
+                                                       add_dynamic_output!(htlc_success_tx, 0);
+                                                       res.push(htlc_success_tx);
+                                               }
                                        }
-                               }
-                               watch_outputs.push(local_tx.tx.output[transaction_output_index as usize].clone());
+                                       watch_outputs.push(local_tx.tx.output[transaction_output_index as usize].clone());
+                               } else { panic!("Should have sigs for non-dust local tx outputs!") }
                        }
                }
 
@@ -1801,11 +1792,12 @@ impl ChannelMonitor {
                // needs to use the same logic as the revoked-tx-announe logic - checking the last two
                // remote commitment transactions. This probably has implications for what data we need to
                // store in local commitment transactions.
-               // TODO: We need to consider HTLCs which were below dust threshold here - while they don't
+               // Note that we consider HTLCs which were below dust threshold here - while they don't
                // strictly imply that we need to fail the channel, we need to go ahead and fail them back
                // to the source, and if we don't fail the channel we will have to ensure that the next
                // updates that peer sends us are update_fails, failing the channel if not. It's probably
                // easier to just fail the channel as this case should be rare enough anyway.
+               // TODO: Test below dust HTLC channel failing
                if let Some(ref cur_local_tx) = self.current_local_signed_commitment_tx {
                        for &(ref htlc, _, _) in cur_local_tx.htlc_outputs.iter() {
                                // For inbound HTLCs which we know the preimage for, we have to ensure we hit the
@@ -1850,42 +1842,40 @@ impl ChannelMonitor {
                        let offered_preimage_claim = input.witness.len() == 3 && input.witness[2].len() == OFFERED_HTLC_SCRIPT_WEIGHT;
 
                        macro_rules! log_claim {
-                               ($source: expr, $local_tx: expr, $outbound_htlc: expr, $payment_hash: expr, $source_avail: expr) => {
+                               ($tx_info: expr, $local_tx: expr, $htlc: expr, $source_avail: expr) => {
                                        // We found the output in question, but aren't failing it backwards
                                        // as we have no corresponding source. This implies either it is an
                                        // inbound HTLC or an outbound HTLC on a revoked transaction.
+                                       let outbound_htlc = $local_tx == $htlc.offered;
                                        if ($local_tx && revocation_sig_claim) ||
-                                                       ($outbound_htlc && !$source_avail && (accepted_preimage_claim || offered_preimage_claim)) {
+                                                       (outbound_htlc && !$source_avail && (accepted_preimage_claim || offered_preimage_claim)) {
                                                log_error!(self, "Input spending {} ({}:{}) in {} resolves {} HTLC with payment hash {} with {}!",
-                                                       $source, input.previous_output.txid, input.previous_output.vout, tx.txid(),
-                                                       if $outbound_htlc { "outbound" } else { "inbound" }, log_bytes!($payment_hash.0),
+                                                       $tx_info, input.previous_output.txid, input.previous_output.vout, tx.txid(),
+                                                       if outbound_htlc { "outbound" } else { "inbound" }, log_bytes!($htlc.payment_hash.0),
                                                        if revocation_sig_claim { "revocation sig" } else { "preimage claim after we'd passed the HTLC resolution back" });
                                        } else {
                                                log_info!(self, "Input spending {} ({}:{}) in {} resolves {} HTLC with payment hash {} with {}",
-                                                       $source, input.previous_output.txid, input.previous_output.vout, tx.txid(),
-                                                       if $outbound_htlc { "outbound" } else { "inbound" }, log_bytes!($payment_hash.0),
+                                                       $tx_info, input.previous_output.txid, input.previous_output.vout, tx.txid(),
+                                                       if outbound_htlc { "outbound" } else { "inbound" }, log_bytes!($htlc.payment_hash.0),
                                                        if revocation_sig_claim { "revocation sig" } else if accepted_preimage_claim || offered_preimage_claim { "preimage" } else { "timeout" });
                                        }
                                }
                        }
 
                        macro_rules! scan_commitment {
-                               ($htlc_outputs: expr, $htlc_sources: expr, $source: expr, $local_tx: expr) => {
-                                       for &(ref payment_hash, ref source, ref vout) in $htlc_sources.iter() {
-                                               if &Some(input.previous_output.vout) == vout {
-                                                       log_claim!($source, $local_tx, true, payment_hash, true);
-                                                       // We have a resolution of an HTLC either from one of our latest
-                                                       // local commitment transactions or an unrevoked remote commitment
-                                                       // transaction. This implies we either learned a preimage, the HTLC
-                                                       // has timed out, or we screwed up. In any case, we should now
-                                                       // resolve the source HTLC with the original sender.
-                                                       payment_data = Some((source.clone(), *payment_hash));
-                                               }
-                                       }
-                                       if payment_data.is_none() {
-                                               for htlc_output in $htlc_outputs {
-                                                       if Some(input.previous_output.vout) == htlc_output.transaction_output_index {
-                                                               log_claim!($source, $local_tx, $local_tx == htlc_output.offered, htlc_output.payment_hash, false);
+                               ($htlcs: expr, $tx_info: expr, $local_tx: expr) => {
+                                       for (ref htlc_output, source_option) in $htlcs {
+                                               if Some(input.previous_output.vout) == htlc_output.transaction_output_index {
+                                                       if let Some(ref source) = source_option {
+                                                               log_claim!($tx_info, $local_tx, htlc_output, true);
+                                                               // We have a resolution of an HTLC either from one of our latest
+                                                               // local commitment transactions or an unrevoked remote commitment
+                                                               // transaction. This implies we either learned a preimage, the HTLC
+                                                               // has timed out, or we screwed up. In any case, we should now
+                                                               // resolve the source HTLC with the original sender.
+                                                               payment_data = Some(((*source).clone(), htlc_output.payment_hash));
+                                                       } else {
+                                                               log_claim!($tx_info, $local_tx, htlc_output, false);
                                                                continue 'outer_loop;
                                                        }
                                                }
@@ -1895,20 +1885,19 @@ impl ChannelMonitor {
 
                        if let Some(ref current_local_signed_commitment_tx) = self.current_local_signed_commitment_tx {
                                if input.previous_output.txid == current_local_signed_commitment_tx.txid {
-                                       scan_commitment!(current_local_signed_commitment_tx.htlc_outputs.iter().map(|&(ref a, _, _)| a),
-                                               current_local_signed_commitment_tx.htlc_sources,
+                                       scan_commitment!(current_local_signed_commitment_tx.htlc_outputs.iter().map(|&(ref a, _, ref b)| (a, b.as_ref())),
                                                "our latest local commitment tx", true);
                                }
                        }
                        if let Some(ref prev_local_signed_commitment_tx) = self.prev_local_signed_commitment_tx {
                                if input.previous_output.txid == prev_local_signed_commitment_tx.txid {
-                                       scan_commitment!(prev_local_signed_commitment_tx.htlc_outputs.iter().map(|&(ref a, _, _)| a),
-                                               prev_local_signed_commitment_tx.htlc_sources,
+                                       scan_commitment!(prev_local_signed_commitment_tx.htlc_outputs.iter().map(|&(ref a, _, ref b)| (a, b.as_ref())),
                                                "our previous local commitment tx", true);
                                }
                        }
-                       if let Some(&(ref htlc_outputs, ref htlc_sources)) = self.remote_claimable_outpoints.get(&input.previous_output.txid) {
-                               scan_commitment!(htlc_outputs, htlc_sources, "remote commitment tx", false);
+                       if let Some(ref htlc_outputs) = self.remote_claimable_outpoints.get(&input.previous_output.txid) {
+                               scan_commitment!(htlc_outputs.iter().map(|&(ref a, ref b)| (a, (b.as_ref().clone()).map(|boxed| &**boxed))),
+                                       "remote commitment tx", false);
                        }
 
                        // Check that scan_commitment, above, decided there is some source worth relaying an
@@ -2044,35 +2033,16 @@ impl<R: ::std::io::Read> ReadableArgs<R, Arc<Logger>> for (Sha256dHash, ChannelM
                        }
                }
 
-               macro_rules! read_htlc_source {
-                       () => {
-                               {
-                                       (Readable::read(reader)?, Readable::read(reader)?,
-                                               match <u8 as Readable<R>>::read(reader)? {
-                                                       0 => None,
-                                                       1 => Some(Readable::read(reader)?),
-                                                       _ => return Err(DecodeError::InvalidValue),
-                                               }
-                                       )
-                               }
-                       }
-               }
-
                let remote_claimable_outpoints_len: u64 = Readable::read(reader)?;
                let mut remote_claimable_outpoints = HashMap::with_capacity(cmp::min(remote_claimable_outpoints_len as usize, MAX_ALLOC_SIZE / 64));
                for _ in 0..remote_claimable_outpoints_len {
                        let txid: Sha256dHash = Readable::read(reader)?;
-                       let outputs_count: u64 = Readable::read(reader)?;
-                       let mut outputs = Vec::with_capacity(cmp::min(outputs_count as usize, MAX_ALLOC_SIZE / 32));
-                       for _ in 0..outputs_count {
-                               outputs.push(read_htlc_in_commitment!());
-                       }
-                       let sources_count: u64 = Readable::read(reader)?;
-                       let mut sources = Vec::with_capacity(cmp::min(sources_count as usize, MAX_ALLOC_SIZE / 32));
-                       for _ in 0..sources_count {
-                               sources.push(read_htlc_source!());
+                       let htlcs_count: u64 = Readable::read(reader)?;
+                       let mut htlcs = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
+                       for _ in 0..htlcs_count {
+                               htlcs.push((read_htlc_in_commitment!(), read_option!().map(|o: HTLCSource| Box::new(o))));
                        }
-                       if let Some(_) = remote_claimable_outpoints.insert(txid, (outputs, sources)) {
+                       if let Some(_) = remote_claimable_outpoints.insert(txid, htlcs) {
                                return Err(DecodeError::InvalidValue);
                        }
                }
@@ -2124,23 +2094,22 @@ impl<R: ::std::io::Read> ReadableArgs<R, Arc<Logger>> for (Sha256dHash, ChannelM
                                        let delayed_payment_key = Readable::read(reader)?;
                                        let feerate_per_kw: u64 = Readable::read(reader)?;
 
-                                       let htlc_outputs_len: u64 = Readable::read(reader)?;
-                                       let mut htlc_outputs = Vec::with_capacity(cmp::min(htlc_outputs_len as usize, MAX_ALLOC_SIZE / 128));
-                                       for _ in 0..htlc_outputs_len {
-                                               let out = read_htlc_in_commitment!();
-                                               let sigs = (Readable::read(reader)?, Readable::read(reader)?);
-                                               htlc_outputs.push((out, sigs.0, sigs.1));
-                                       }
-
-                                       let htlc_sources_len: u64 = Readable::read(reader)?;
-                                       let mut htlc_sources = Vec::with_capacity(cmp::min(htlc_outputs_len as usize, MAX_ALLOC_SIZE / 128));
-                                       for _ in 0..htlc_sources_len {
-                                               htlc_sources.push(read_htlc_source!());
+                                       let htlcs_len: u64 = Readable::read(reader)?;
+                                       let mut htlcs = Vec::with_capacity(cmp::min(htlcs_len as usize, MAX_ALLOC_SIZE / 128));
+                                       for _ in 0..htlcs_len {
+                                               let htlc = read_htlc_in_commitment!();
+                                               let sigs = match <u8 as Readable<R>>::read(reader)? {
+                                                       0 => None,
+                                                       1 => Some((Readable::read(reader)?, Readable::read(reader)?)),
+                                                       _ => return Err(DecodeError::InvalidValue),
+                                               };
+                                               htlcs.push((htlc, sigs, read_option!()));
                                        }
 
                                        LocalSignedTx {
                                                txid: tx.txid(),
-                                               tx, revocation_key, a_htlc_key, b_htlc_key, delayed_payment_key, feerate_per_kw, htlc_outputs, htlc_sources
+                                               tx, revocation_key, a_htlc_key, b_htlc_key, delayed_payment_key, feerate_per_kw,
+                                               htlc_outputs: htlcs
                                        }
                                }
                        }
@@ -2220,7 +2189,7 @@ mod tests {
        use ln::chan_utils::{HTLCOutputInCommitment, TxCreationKeys};
        use util::test_utils::TestLogger;
        use secp256k1::key::{SecretKey,PublicKey};
-       use secp256k1::{Secp256k1, Signature};
+       use secp256k1::Secp256k1;
        use rand::{thread_rng,Rng};
        use std::sync::Arc;
 
@@ -2583,7 +2552,6 @@ mod tests {
        fn test_prune_preimages() {
                let secp_ctx = Secp256k1::new();
                let logger = Arc::new(TestLogger::new());
-               let dummy_sig = Signature::from_der(&secp_ctx, &hex::decode("3045022100fa86fa9a36a8cd6a7bb8f06a541787d51371d067951a9461d5404de6b928782e02201c8b7c334c10aed8976a3a465be9a28abff4cb23acbf00022295b378ce1fa3cd").unwrap()[..]).unwrap();
 
                let dummy_key = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &[42; 32]).unwrap());
                macro_rules! dummy_keys {
@@ -2618,13 +2586,13 @@ mod tests {
                                {
                                        let mut res = Vec::new();
                                        for (idx, preimage) in $preimages_slice.iter().enumerate() {
-                                               res.push(HTLCOutputInCommitment {
+                                               res.push((HTLCOutputInCommitment {
                                                        offered: true,
                                                        amount_msat: 0,
                                                        cltv_expiry: 0,
                                                        payment_hash: preimage.1.clone(),
                                                        transaction_output_index: Some(idx as u32),
-                                               });
+                                               }, None));
                                        }
                                        res
                                }
@@ -2634,7 +2602,7 @@ mod tests {
                        ($preimages_slice: expr) => {
                                {
                                        let mut inp = preimages_slice_to_htlc_outputs!($preimages_slice);
-                                       let res: Vec<_> = inp.drain(..).map(|e| { (e, dummy_sig.clone(), dummy_sig.clone()) }).collect();
+                                       let res: Vec<_> = inp.drain(..).map(|e| { (e.0, None, e.1) }).collect();
                                        res
                                }
                        }
@@ -2653,11 +2621,11 @@ mod tests {
                let mut monitor = ChannelMonitor::new(&SecretKey::from_slice(&secp_ctx, &[42; 32]).unwrap(), &SecretKey::from_slice(&secp_ctx, &[43; 32]).unwrap(), &SecretKey::from_slice(&secp_ctx, &[44; 32]).unwrap(), &SecretKey::from_slice(&secp_ctx, &[44; 32]).unwrap(), &PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &[45; 32]).unwrap()), 0, Script::new(), logger.clone());
                monitor.set_their_to_self_delay(10);
 
-               monitor.provide_latest_local_commitment_tx_info(dummy_tx.clone(), dummy_keys!(), 0, preimages_to_local_htlcs!(preimages[0..10]), Vec::new());
-               monitor.provide_latest_remote_commitment_tx_info(&dummy_tx, preimages_slice_to_htlc_outputs!(preimages[5..15]), Vec::new(), 281474976710655, dummy_key);
-               monitor.provide_latest_remote_commitment_tx_info(&dummy_tx, preimages_slice_to_htlc_outputs!(preimages[15..20]), Vec::new(), 281474976710654, dummy_key);
-               monitor.provide_latest_remote_commitment_tx_info(&dummy_tx, preimages_slice_to_htlc_outputs!(preimages[17..20]), Vec::new(), 281474976710653, dummy_key);
-               monitor.provide_latest_remote_commitment_tx_info(&dummy_tx, preimages_slice_to_htlc_outputs!(preimages[18..20]), Vec::new(), 281474976710652, dummy_key);
+               monitor.provide_latest_local_commitment_tx_info(dummy_tx.clone(), dummy_keys!(), 0, preimages_to_local_htlcs!(preimages[0..10]));
+               monitor.provide_latest_remote_commitment_tx_info(&dummy_tx, preimages_slice_to_htlc_outputs!(preimages[5..15]), 281474976710655, dummy_key);
+               monitor.provide_latest_remote_commitment_tx_info(&dummy_tx, preimages_slice_to_htlc_outputs!(preimages[15..20]), 281474976710654, dummy_key);
+               monitor.provide_latest_remote_commitment_tx_info(&dummy_tx, preimages_slice_to_htlc_outputs!(preimages[17..20]), 281474976710653, dummy_key);
+               monitor.provide_latest_remote_commitment_tx_info(&dummy_tx, preimages_slice_to_htlc_outputs!(preimages[18..20]), 281474976710652, dummy_key);
                for &(ref preimage, ref hash) in preimages.iter() {
                        monitor.provide_payment_preimage(hash, preimage);
                }
@@ -2679,7 +2647,7 @@ mod tests {
 
                // Now update local commitment tx info, pruning only element 18 as we still care about the
                // previous commitment tx's preimages too
-               monitor.provide_latest_local_commitment_tx_info(dummy_tx.clone(), dummy_keys!(), 0, preimages_to_local_htlcs!(preimages[0..5]), Vec::new());
+               monitor.provide_latest_local_commitment_tx_info(dummy_tx.clone(), dummy_keys!(), 0, preimages_to_local_htlcs!(preimages[0..5]));
                secret[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
                monitor.provide_secret(281474976710653, secret.clone()).unwrap();
                assert_eq!(monitor.payment_preimages.len(), 12);
@@ -2687,7 +2655,7 @@ mod tests {
                test_preimages_exist!(&preimages[18..20], monitor);
 
                // But if we do it again, we'll prune 5-10
-               monitor.provide_latest_local_commitment_tx_info(dummy_tx.clone(), dummy_keys!(), 0, preimages_to_local_htlcs!(preimages[0..3]), Vec::new());
+               monitor.provide_latest_local_commitment_tx_info(dummy_tx.clone(), dummy_keys!(), 0, preimages_to_local_htlcs!(preimages[0..3]));
                secret[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
                monitor.provide_secret(281474976710652, secret.clone()).unwrap();
                assert_eq!(monitor.payment_preimages.len(), 5);