Track HTLCSource in ChannelMonitor
[rust-lightning] / src / ln / channelmonitor.rs
index 8b209c1e7b00e94ca8f69767ce808f5df4b93223..15be91c30e760548b1cccaae96a411d6d3d702d1 100644 (file)
@@ -26,9 +26,10 @@ use secp256k1::{Secp256k1,Message,Signature};
 use secp256k1::key::{SecretKey,PublicKey};
 use secp256k1;
 
-use ln::msgs::{DecodeError, HandleError};
+use ln::msgs::DecodeError;
 use ln::chan_utils;
 use ln::chan_utils::HTLCOutputInCommitment;
+use ln::channelmanager::HTLCSource;
 use chain::chaininterface::{ChainListener, ChainWatchInterface, BroadcasterInterface};
 use chain::transaction::OutPoint;
 use chain::keysinterface::SpendableOutputDescriptor;
@@ -71,9 +72,19 @@ pub enum ChannelMonitorUpdateErr {
        /// Used to indicate no further channel monitor updates will be allowed (eg we've moved on to a
        /// different watchtower and cannot update with all watchtowers that were previously informed
        /// of this channel). This will force-close the channel in question.
+       ///
+       /// Should also be used to indicate a failure to update the local copy of the channel monitor.
        PermanentFailure,
 }
 
+/// General Err type for ChannelMonitor actions. Generally, this implies that the data provided is
+/// inconsistent with the ChannelMonitor being called. eg for ChannelMonitor::insert_combine this
+/// means you tried to merge two monitors for different channels or for a channel which was
+/// restored from a backup and then generated new commitment updates.
+/// Contains a human-readable error message.
+#[derive(Debug)]
+pub struct MonitorUpdateError(pub &'static str);
+
 /// Simple trait indicating ability to track a set of ChannelMonitors and multiplex events between
 /// them. Generally should be implemented by keeping a local SimpleManyChannelMonitor and passing
 /// events to it, while also taking any add_update_monitor events and passing them to some remote
@@ -158,25 +169,31 @@ impl<Key : Send + cmp::Eq + hash::Hash + 'static> SimpleManyChannelMonitor<Key>
        }
 
        /// Adds or udpates the monitor which monitors the channel referred to by the given key.
-       pub fn add_update_monitor_by_key(&self, key: Key, monitor: ChannelMonitor) -> Result<(), HandleError> {
+       pub fn add_update_monitor_by_key(&self, key: Key, monitor: ChannelMonitor) -> Result<(), MonitorUpdateError> {
                let mut monitors = self.monitors.lock().unwrap();
                match monitors.get_mut(&key) {
                        Some(orig_monitor) => {
-                               log_trace!(self, "Updating Channel Monitor for channel {}", log_funding_option!(monitor.funding_txo));
+                               log_trace!(self, "Updating Channel Monitor for channel {}", log_funding_info!(monitor.key_storage));
                                return orig_monitor.insert_combine(monitor);
                        },
                        None => {}
                };
-               match &monitor.funding_txo {
-                       &None => {
-                               log_trace!(self, "Got new Channel Monitor for no-funding-set channel (monitoring all txn!)");
-                               self.chain_monitor.watch_all_txn()
-                       },
-                       &Some((ref outpoint, ref script)) => {
-                               log_trace!(self, "Got new Channel Monitor for channel {}", log_bytes!(outpoint.to_channel_id()[..]));
-                               self.chain_monitor.install_watch_tx(&outpoint.txid, script);
-                               self.chain_monitor.install_watch_outpoint((outpoint.txid, outpoint.index as u32), script);
+               match monitor.key_storage {
+                       Storage::Local { ref funding_info, .. } => {
+                               match funding_info {
+                                       &None => {
+                                               return Err(MonitorUpdateError("Try to update a useless monitor without funding_txo !"));
+                                       },
+                                       &Some((ref outpoint, ref script)) => {
+                                               log_trace!(self, "Got new Channel Monitor for channel {}", log_bytes!(outpoint.to_channel_id()[..]));
+                                               self.chain_monitor.install_watch_tx(&outpoint.txid, script);
+                                               self.chain_monitor.install_watch_outpoint((outpoint.txid, outpoint.index as u32), script);
+                                       },
+                               }
                        },
+                       Storage::Watchtower { .. } => {
+                               self.chain_monitor.watch_all_txn();
+                       }
                }
                monitors.insert(key, monitor);
                Ok(())
@@ -215,8 +232,8 @@ pub(crate) const CLTV_CLAIM_BUFFER: u32 = 6;
 pub(crate) const HTLC_FAIL_TIMEOUT_BLOCKS: u32 = 3;
 
 #[derive(Clone, PartialEq)]
-enum KeyStorage {
-       PrivMode {
+enum Storage {
+       Local {
                revocation_base_key: SecretKey,
                htlc_base_key: SecretKey,
                delayed_payment_base_key: SecretKey,
@@ -224,11 +241,11 @@ enum KeyStorage {
                shutdown_pubkey: PublicKey,
                prev_latest_per_commitment_point: Option<PublicKey>,
                latest_per_commitment_point: Option<PublicKey>,
+               funding_info: Option<(OutPoint, Script)>,
        },
-       SigsMode {
+       Watchtower {
                revocation_base_key: PublicKey,
                htlc_base_key: PublicKey,
-               sigs: HashMap<Sha256dHash, Signature>,
        }
 }
 
@@ -243,6 +260,7 @@ struct LocalSignedTx {
        delayed_payment_key: PublicKey,
        feerate_per_kw: u64,
        htlc_outputs: Vec<(HTLCOutputInCommitment, Signature, Signature)>,
+       htlc_sources: Vec<([u8; 32], HTLCSource, Option<u32>)>,
 }
 
 const SERIALIZATION_VERSION: u8 = 1;
@@ -255,10 +273,9 @@ const MIN_SERIALIZATION_VERSION: u8 = 1;
 /// information and are actively monitoring the chain.
 #[derive(Clone)]
 pub struct ChannelMonitor {
-       funding_txo: Option<(OutPoint, Script)>,
        commitment_transaction_number_obscure_factor: u64,
 
-       key_storage: KeyStorage,
+       key_storage: Storage,
        their_htlc_base_key: Option<PublicKey>,
        their_delayed_payment_base_key: Option<PublicKey>,
        // first is the idx of the first of the two revocation points
@@ -268,7 +285,7 @@ pub struct ChannelMonitor {
        their_to_self_delay: Option<u16>,
 
        old_secrets: [([u8; 32], u64); 49],
-       remote_claimable_outpoints: HashMap<Sha256dHash, Vec<HTLCOutputInCommitment>>,
+       remote_claimable_outpoints: HashMap<Sha256dHash, (Vec<HTLCOutputInCommitment>, Vec<([u8; 32], HTLCSource, Option<u32>)>)>,
        /// 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
@@ -311,8 +328,7 @@ pub struct ChannelMonitor {
 /// underlying object
 impl PartialEq for ChannelMonitor {
        fn eq(&self, other: &Self) -> bool {
-               if self.funding_txo != other.funding_txo ||
-                       self.commitment_transaction_number_obscure_factor != other.commitment_transaction_number_obscure_factor ||
+               if self.commitment_transaction_number_obscure_factor != other.commitment_transaction_number_obscure_factor ||
                        self.key_storage != other.key_storage ||
                        self.their_htlc_base_key != other.their_htlc_base_key ||
                        self.their_delayed_payment_base_key != other.their_delayed_payment_base_key ||
@@ -343,10 +359,9 @@ impl PartialEq for ChannelMonitor {
 impl ChannelMonitor {
        pub(super) fn new(revocation_base_key: &SecretKey, delayed_payment_base_key: &SecretKey, htlc_base_key: &SecretKey, payment_base_key: &SecretKey, shutdown_pubkey: &PublicKey, our_to_self_delay: u16, destination_script: Script, logger: Arc<Logger>) -> ChannelMonitor {
                ChannelMonitor {
-                       funding_txo: None,
                        commitment_transaction_number_obscure_factor: 0,
 
-                       key_storage: KeyStorage::PrivMode {
+                       key_storage: Storage::Local {
                                revocation_base_key: revocation_base_key.clone(),
                                htlc_base_key: htlc_base_key.clone(),
                                delayed_payment_base_key: delayed_payment_base_key.clone(),
@@ -354,6 +369,7 @@ impl ChannelMonitor {
                                shutdown_pubkey: shutdown_pubkey.clone(),
                                prev_latest_per_commitment_point: None,
                                latest_per_commitment_point: None,
+                               funding_info: None,
                        },
                        their_htlc_base_key: None,
                        their_delayed_payment_base_key: None,
@@ -408,12 +424,12 @@ impl ChannelMonitor {
        /// Inserts a revocation secret into this channel monitor. Prunes old preimages if neither
        /// needed by local commitment transactions HTCLs nor by remote ones. Unless we haven't already seen remote
        /// commitment transaction's secret, they are de facto pruned (we can use revocation key).
-       pub(super) fn provide_secret(&mut self, idx: u64, secret: [u8; 32]) -> Result<(), HandleError> {
+       pub(super) fn provide_secret(&mut self, idx: u64, secret: [u8; 32]) -> Result<(), MonitorUpdateError> {
                let pos = ChannelMonitor::place_secret(idx);
                for i in 0..pos {
                        let (old_secret, old_idx) = self.old_secrets[i as usize];
                        if ChannelMonitor::derive_secret(secret, pos, old_idx) != old_secret {
-                               return Err(HandleError{err: "Previous secret did not match new one", action: None})
+                               return Err(MonitorUpdateError("Previous secret did not match new one"));
                        }
                }
                self.old_secrets[pos as usize] = (secret, idx);
@@ -453,46 +469,44 @@ impl ChannelMonitor {
                Ok(())
        }
 
-       /// Tracks the next revocation point which may be required to claim HTLC outputs which we know
-       /// the preimage of in case the remote end force-closes using their latest state. When called at
-       /// channel opening revocation point is the CURRENT one used for first commitment tx. Needed in case of sizeable push_msat.
-       pub(super) fn provide_their_next_revocation_point(&mut self, their_next_revocation_point: Option<(u64, PublicKey)>) {
-               if let Some(new_revocation_point) = their_next_revocation_point {
-                       match self.their_cur_revocation_points {
-                               Some(old_points) => {
-                                       if old_points.0 == new_revocation_point.0 + 1 {
-                                               self.their_cur_revocation_points = Some((old_points.0, old_points.1, Some(new_revocation_point.1)));
-                                       } else if old_points.0 == new_revocation_point.0 + 2 {
-                                               if let Some(old_second_point) = old_points.2 {
-                                                       self.their_cur_revocation_points = Some((old_points.0 - 1, old_second_point, Some(new_revocation_point.1)));
-                                               } else {
-                                                       self.their_cur_revocation_points = Some((new_revocation_point.0, new_revocation_point.1, None));
-                                               }
-                                       } else {
-                                               self.their_cur_revocation_points = Some((new_revocation_point.0, new_revocation_point.1, None));
-                                       }
-                               },
-                               None => {
-                                       self.their_cur_revocation_points = Some((new_revocation_point.0, new_revocation_point.1, None));
-                               }
-                       }
-               }
-       }
-
        /// Informs this monitor of the latest remote (ie non-broadcastable) commitment transaction.
        /// 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>, commitment_number: u64) {
+       pub(super) fn provide_latest_remote_commitment_tx_info(&mut self, unsigned_commitment_tx: &Transaction, htlc_outputs: Vec<HTLCOutputInCommitment>, htlc_sources: Vec<([u8; 32], HTLCSource, Option<u32>)>, 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 htlc in &htlc_outputs {
+               for ref htlc in &htlc_outputs {
                        self.remote_hash_commitment_number.insert(htlc.payment_hash, commitment_number);
                }
-               self.remote_claimable_outpoints.insert(unsigned_commitment_tx.txid(), htlc_outputs);
+               // We prune old claimable outpoints, useless to pass backward state when remote commitment
+               // tx get revoked, optimize for storage
+               for (_, htlc_data) in self.remote_claimable_outpoints.iter_mut() {
+                       htlc_data.1 = Vec::new();
+               }
+               self.remote_claimable_outpoints.insert(unsigned_commitment_tx.txid(), (htlc_outputs, htlc_sources));
                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 {
+                       Some(old_points) => {
+                               if old_points.0 == commitment_number + 1 {
+                                       self.their_cur_revocation_points = Some((old_points.0, old_points.1, Some(their_revocation_point)));
+                               } else if old_points.0 == commitment_number + 2 {
+                                       if let Some(old_second_point) = old_points.2 {
+                                               self.their_cur_revocation_points = Some((old_points.0 - 1, old_second_point, Some(their_revocation_point)));
+                                       } else {
+                                               self.their_cur_revocation_points = Some((commitment_number, their_revocation_point, None));
+                                       }
+                               } else {
+                                       self.their_cur_revocation_points = Some((commitment_number, their_revocation_point, None));
+                               }
+                       },
+                       None => {
+                               self.their_cur_revocation_points = Some((commitment_number, their_revocation_point, None));
+                       }
+               }
        }
 
        /// Informs this monitor of the latest local (ie broadcastable) commitment transaction. The
@@ -500,9 +514,9 @@ impl ChannelMonitor {
        /// is important that any clones of this channel monitor (including remote clones) by kept
        /// up-to-date as our local commitment transaction is updated.
        /// Panics if set_their_to_self_delay has never been called.
-       /// Also update KeyStorage with latest local per_commitment_point to derive local_delayedkey in
+       /// 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)>) {
+       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<([u8; 32], HTLCSource, Option<u32>)>) {
                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 {
@@ -514,18 +528,14 @@ impl ChannelMonitor {
                        delayed_payment_key: local_keys.a_delayed_payment_key,
                        feerate_per_kw,
                        htlc_outputs,
+                       htlc_sources,
                });
-               self.key_storage = if let KeyStorage::PrivMode { ref revocation_base_key, ref htlc_base_key, ref delayed_payment_base_key, ref payment_base_key, ref shutdown_pubkey, ref latest_per_commitment_point, .. } = self.key_storage {
-                       KeyStorage::PrivMode {
-                               revocation_base_key: *revocation_base_key,
-                               htlc_base_key: *htlc_base_key,
-                               delayed_payment_base_key: *delayed_payment_base_key,
-                               payment_base_key: *payment_base_key,
-                               shutdown_pubkey: *shutdown_pubkey,
-                               prev_latest_per_commitment_point: *latest_per_commitment_point,
-                               latest_per_commitment_point: Some(local_keys.per_commitment_point),
-                       }
-               } else { unimplemented!(); };
+
+               if let Storage::Local { ref mut latest_per_commitment_point, .. } = self.key_storage {
+                       *latest_per_commitment_point = Some(local_keys.per_commitment_point);
+               } else {
+                       panic!("Channel somehow ended up with its internal ChannelMonitor being in Watchtower mode?");
+               }
        }
 
        /// Provides a payment_hash->payment_preimage mapping. Will be automatically pruned when all
@@ -537,21 +547,44 @@ impl ChannelMonitor {
        /// Combines this ChannelMonitor with the information contained in the other ChannelMonitor.
        /// After a successful call this ChannelMonitor is up-to-date and is safe to use to monitor the
        /// chain for new blocks/transactions.
-       pub fn insert_combine(&mut self, mut other: ChannelMonitor) -> Result<(), HandleError> {
-               if self.funding_txo.is_some() {
-                       // We should be able to compare the entire funding_txo, but in fuzztarget its trivially
-                       // easy to collide the funding_txo hash and have a different scriptPubKey.
-                       if other.funding_txo.is_some() && other.funding_txo.as_ref().unwrap().0 != self.funding_txo.as_ref().unwrap().0 {
-                               return Err(HandleError{err: "Funding transaction outputs are not identical!", action: None});
-                       }
-               } else {
-                       self.funding_txo = other.funding_txo.take();
+       pub fn insert_combine(&mut self, mut other: ChannelMonitor) -> Result<(), MonitorUpdateError> {
+               match self.key_storage {
+                       Storage::Local { ref funding_info, .. } => {
+                               if funding_info.is_none() { return Err(MonitorUpdateError("Try to combine a Local monitor without funding_info")); }
+                               let our_funding_info = funding_info;
+                               if let Storage::Local { ref funding_info, .. } = other.key_storage {
+                                       if funding_info.is_none() { return Err(MonitorUpdateError("Try to combine a Local monitor without funding_info")); }
+                                       // We should be able to compare the entire funding_txo, but in fuzztarget its trivially
+                                       // easy to collide the funding_txo hash and have a different scriptPubKey.
+                                       if funding_info.as_ref().unwrap().0 != our_funding_info.as_ref().unwrap().0 {
+                                               return Err(MonitorUpdateError("Funding transaction outputs are not identical!"));
+                                       }
+                               } else {
+                                       return Err(MonitorUpdateError("Try to combine a Local monitor with a Watchtower one !"));
+                               }
+                       },
+                       Storage::Watchtower { .. } => {
+                               if let Storage::Watchtower { .. } = other.key_storage {
+                                       unimplemented!();
+                               } else {
+                                       return Err(MonitorUpdateError("Try to combine a Watchtower monitor with a Local one !"));
+                               }
+                       },
                }
                let other_min_secret = other.get_min_seen_secret();
                let our_min_secret = self.get_min_seen_secret();
                if our_min_secret > other_min_secret {
                        self.provide_secret(other_min_secret, other.get_secret(other_min_secret).unwrap())?;
                }
+               if let Some(ref local_tx) = self.current_local_signed_commitment_tx {
+                       if let Some(ref other_local_tx) = other.current_local_signed_commitment_tx {
+                               let our_commitment_number = 0xffffffffffff - ((((local_tx.tx.input[0].sequence as u64 & 0xffffff) << 3*8) | (local_tx.tx.lock_time as u64 & 0xffffff)) ^ self.commitment_transaction_number_obscure_factor);
+                               let other_commitment_number = 0xffffffffffff - ((((other_local_tx.tx.input[0].sequence as u64 & 0xffffff) << 3*8) | (other_local_tx.tx.lock_time as u64 & 0xffffff)) ^ other.commitment_transaction_number_obscure_factor);
+                               if our_commitment_number >= other_commitment_number {
+                                       self.key_storage = other.key_storage;
+                               }
+                       }
+               }
                // TODO: We should use current_remote_commitment_number and the commitment number out of
                // local transactions to decide how to merge
                if our_min_secret >= other_min_secret {
@@ -567,6 +600,7 @@ impl ChannelMonitor {
                        }
                        self.payment_preimages = other.payment_preimages;
                }
+
                self.current_remote_commitment_number = cmp::min(self.current_remote_commitment_number, other.current_remote_commitment_number);
                Ok(())
        }
@@ -583,8 +617,15 @@ impl ChannelMonitor {
        /// provides slightly better privacy.
        /// It's the responsibility of the caller to register outpoint and script with passing the former
        /// value as key to add_update_monitor.
-       pub(super) fn set_funding_info(&mut self, funding_info: (OutPoint, Script)) {
-               self.funding_txo = Some(funding_info);
+       pub(super) fn set_funding_info(&mut self, new_funding_info: (OutPoint, Script)) {
+               match self.key_storage {
+                       Storage::Local { ref mut funding_info, .. } => {
+                               *funding_info = Some(new_funding_info);
+                       },
+                       Storage::Watchtower { .. } => {
+                               panic!("Channel somehow ended up with its internal ChannelMonitor being in Watchtower mode?");
+                       }
+               }
        }
 
        /// We log these base keys at channel opening to being able to rebuild redeemscript in case of leaked revoked commit tx
@@ -598,14 +639,28 @@ impl ChannelMonitor {
        }
 
        pub(super) fn unset_funding_info(&mut self) {
-               self.funding_txo = None;
+               match self.key_storage {
+                       Storage::Local { ref mut funding_info, .. } => {
+                               *funding_info = None;
+                       },
+                       Storage::Watchtower { .. } => {
+                               panic!("Channel somehow ended up with its internal ChannelMonitor being in Watchtower mode?");
+                       },
+               }
        }
 
        /// Gets the funding transaction outpoint of the channel this ChannelMonitor is monitoring for.
        pub fn get_funding_txo(&self) -> Option<OutPoint> {
-               match self.funding_txo {
-                       Some((outpoint, _)) => Some(outpoint),
-                       None => None
+               match self.key_storage {
+                       Storage::Local { ref funding_info, .. } => {
+                               match funding_info {
+                                       &Some((outpoint, _)) => Some(outpoint),
+                                       &None => None
+                               }
+                       },
+                       Storage::Watchtower { .. } => {
+                               return None;
+                       }
                }
        }
 
@@ -630,24 +685,11 @@ impl ChannelMonitor {
                writer.write_all(&[SERIALIZATION_VERSION; 1])?;
                writer.write_all(&[MIN_SERIALIZATION_VERSION; 1])?;
 
-               match &self.funding_txo {
-                       &Some((ref outpoint, ref script)) => {
-                               writer.write_all(&outpoint.txid[..])?;
-                               writer.write_all(&byte_utils::be16_to_array(outpoint.index))?;
-                               script.write(writer)?;
-                       },
-                       &None => {
-                               // We haven't even been initialized...not sure why anyone is serializing us, but
-                               // not much to give them.
-                               return Ok(());
-                       },
-               }
-
                // Set in initial Channel-object creation, so should always be set by now:
                U48(self.commitment_transaction_number_obscure_factor).write(writer)?;
 
                match self.key_storage {
-                       KeyStorage::PrivMode { ref revocation_base_key, ref htlc_base_key, ref delayed_payment_base_key, ref payment_base_key, ref shutdown_pubkey, ref prev_latest_per_commitment_point, ref latest_per_commitment_point } => {
+                       Storage::Local { ref revocation_base_key, ref htlc_base_key, ref delayed_payment_base_key, ref payment_base_key, ref shutdown_pubkey, ref prev_latest_per_commitment_point, ref latest_per_commitment_point, ref funding_info } => {
                                writer.write_all(&[0; 1])?;
                                writer.write_all(&revocation_base_key[..])?;
                                writer.write_all(&htlc_base_key[..])?;
@@ -666,9 +708,18 @@ impl ChannelMonitor {
                                } else {
                                        writer.write_all(&[0; 1])?;
                                }
-
+                               match funding_info  {
+                                       &Some((ref outpoint, ref script)) => {
+                                               writer.write_all(&outpoint.txid[..])?;
+                                               writer.write_all(&byte_utils::be16_to_array(outpoint.index))?;
+                                               script.write(writer)?;
+                                       },
+                                       &None => {
+                                               debug_assert!(false, "Try to serialize a useless Local monitor !");
+                                       },
+                               }
                        },
-                       KeyStorage::SigsMode { .. } => unimplemented!(),
+                       Storage::Watchtower { .. } => unimplemented!(),
                }
 
                writer.write_all(&self.their_htlc_base_key.as_ref().unwrap().serialize())?;
@@ -710,13 +761,31 @@ 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_outputs) in self.remote_claimable_outpoints.iter() {
+               for (ref txid, &(ref htlc_infos, ref htlc_sources)) in self.remote_claimable_outpoints.iter() {
                        writer.write_all(&txid[..])?;
-                       writer.write_all(&byte_utils::be64_to_array(htlc_outputs.len() as u64))?;
-                       for htlc_output in htlc_outputs.iter() {
+                       writer.write_all(&byte_utils::be64_to_array(htlc_infos.len() as u64))?;
+                       for ref htlc_output 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);
+                       }
                }
 
                writer.write_all(&byte_utils::be64_to_array(self.remote_commitment_txn_on_chain.len() as u64))?;
@@ -760,6 +829,10 @@ impl ChannelMonitor {
                                        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);
+                               }
                        }
                }
 
@@ -820,14 +893,14 @@ impl ChannelMonitor {
        //we want to leave out (eg funding_txo, etc).
 
        /// Can only fail if idx is < get_min_seen_secret
-       pub(super) fn get_secret(&self, idx: u64) -> Result<[u8; 32], HandleError> {
+       pub(super) fn get_secret(&self, idx: u64) -> Option<[u8; 32]> {
                for i in 0..self.old_secrets.len() {
                        if (idx & (!((1 << i) - 1))) == self.old_secrets[i].1 {
-                               return Ok(ChannelMonitor::derive_secret(self.old_secrets[i].0, i as u8, idx))
+                               return Some(ChannelMonitor::derive_secret(self.old_secrets[i].0, i as u8, idx))
                        }
                }
                assert!(idx < self.get_min_seen_secret());
-               Err(HandleError{err: "idx too low", action: None})
+               None
        }
 
        pub(super) fn get_min_seen_secret(&self) -> u64 {
@@ -878,16 +951,18 @@ impl ChannelMonitor {
                if commitment_number >= self.get_min_seen_secret() {
                        let secret = self.get_secret(commitment_number).unwrap();
                        let per_commitment_key = ignore_error!(SecretKey::from_slice(&self.secp_ctx, &secret));
-                       let (revocation_pubkey, b_htlc_key) = match self.key_storage {
-                               KeyStorage::PrivMode { ref revocation_base_key, ref htlc_base_key, .. } => {
+                       let (revocation_pubkey, b_htlc_key, local_payment_key) = match self.key_storage {
+                               Storage::Local { ref revocation_base_key, ref htlc_base_key, ref payment_base_key, .. } => {
                                        let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
                                        (ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &PublicKey::from_secret_key(&self.secp_ctx, &revocation_base_key))),
-                                       ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &per_commitment_point, &PublicKey::from_secret_key(&self.secp_ctx, &htlc_base_key))))
+                                       ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &per_commitment_point, &PublicKey::from_secret_key(&self.secp_ctx, &htlc_base_key))),
+                                       Some(ignore_error!(chan_utils::derive_private_key(&self.secp_ctx, &per_commitment_point, &payment_base_key))))
                                },
-                               KeyStorage::SigsMode { ref revocation_base_key, ref htlc_base_key, .. } => {
+                               Storage::Watchtower { ref revocation_base_key, ref htlc_base_key, .. } => {
                                        let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
                                        (ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &revocation_base_key)),
-                                       ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &per_commitment_point, &htlc_base_key)))
+                                       ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &per_commitment_point, &htlc_base_key)),
+                                       None)
                                },
                        };
                        let delayed_key = ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key), &self.their_delayed_payment_base_key.unwrap()));
@@ -899,6 +974,13 @@ impl ChannelMonitor {
                        let revokeable_redeemscript = chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.our_to_self_delay, &delayed_key);
                        let revokeable_p2wsh = revokeable_redeemscript.to_v0_p2wsh();
 
+                       let local_payment_p2wpkh = if let Some(payment_key) = local_payment_key {
+                               // Note that the Network here is ignored as we immediately drop the address for the
+                               // script_pubkey version.
+                               let payment_hash160 = Hash160::from_data(&PublicKey::from_secret_key(&self.secp_ctx, &payment_key).serialize());
+                               Some(Builder::new().push_opcode(opcodes::All::OP_PUSHBYTES_0).push_slice(&payment_hash160[..]).into_script())
+                       } else { None };
+
                        let mut total_value = 0;
                        let mut values = Vec::new();
                        let mut inputs = Vec::new();
@@ -918,23 +1000,12 @@ impl ChannelMonitor {
                                        htlc_idxs.push(None);
                                        values.push(outp.value);
                                        total_value += outp.value;
-                               } else if outp.script_pubkey.is_v0_p2wpkh() {
-                                       match self.key_storage {
-                                               KeyStorage::PrivMode { ref payment_base_key, .. } => {
-                                                       let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
-                                                       if let Ok(local_key) = chan_utils::derive_private_key(&self.secp_ctx, &per_commitment_point, &payment_base_key) {
-                                                               spendable_outputs.push(SpendableOutputDescriptor::DynamicOutputP2WPKH {
-                                                                       outpoint: BitcoinOutPoint { txid: commitment_txid, vout: idx as u32 },
-                                                                       key: local_key,
-                                                                       output: outp.clone(),
-                                                               });
-                                                       }
-                                               }
-                                               KeyStorage::SigsMode { .. } => {
-                                                       //TODO: we need to ensure an offline client will generate the event when it
-                                                       // cames back online after only the watchtower saw the transaction
-                                               }
-                                       }
+                               } else if Some(&outp.script_pubkey) == local_payment_p2wpkh.as_ref() {
+                                       spendable_outputs.push(SpendableOutputDescriptor::DynamicOutputP2WPKH {
+                                               outpoint: BitcoinOutPoint { txid: commitment_txid, vout: idx as u32 },
+                                               key: local_payment_key.unwrap(),
+                                               output: outp.clone(),
+                                       });
                                }
                        }
 
@@ -942,16 +1013,16 @@ impl ChannelMonitor {
                                ($sighash_parts: expr, $input: expr, $htlc_idx: expr, $amount: expr) => {
                                        {
                                                let (sig, redeemscript) = match self.key_storage {
-                                                       KeyStorage::PrivMode { ref revocation_base_key, .. } => {
+                                                       Storage::Local { ref revocation_base_key, .. } => {
                                                                let redeemscript = if $htlc_idx.is_none() { revokeable_redeemscript.clone() } else {
-                                                                       let htlc = &per_commitment_option.unwrap()[$htlc_idx.unwrap()];
+                                                                       let htlc = &per_commitment_option.unwrap().0[$htlc_idx.unwrap()];
                                                                        chan_utils::get_htlc_redeemscript_with_explicit_keys(htlc, &a_htlc_key, &b_htlc_key, &revocation_pubkey)
                                                                };
                                                                let sighash = ignore_error!(Message::from_slice(&$sighash_parts.sighash_all(&$input, &redeemscript, $amount)[..]));
                                                                let revocation_key = ignore_error!(chan_utils::derive_private_revocation_key(&self.secp_ctx, &per_commitment_key, &revocation_base_key));
                                                                (self.secp_ctx.sign(&sighash, &revocation_key), redeemscript)
                                                        },
-                                                       KeyStorage::SigsMode { .. } => {
+                                                       Storage::Watchtower { .. } => {
                                                                unimplemented!();
                                                        }
                                                };
@@ -967,10 +1038,10 @@ impl ChannelMonitor {
                                }
                        }
 
-                       if let Some(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, htlc) in per_commitment_data.iter().enumerate() {
+                               for (idx, ref htlc) in per_commitment_data.iter().enumerate() {
                                        let expected_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &a_htlc_key, &b_htlc_key, &revocation_pubkey);
                                        if htlc.transaction_output_index as usize >= tx.output.len() ||
                                                        tx.output[htlc.transaction_output_index as usize].value != htlc.amount_msat / 1000 ||
@@ -1058,11 +1129,11 @@ impl ChannelMonitor {
                                        } else { None };
                                if let Some(revocation_point) = revocation_point_option {
                                        let (revocation_pubkey, b_htlc_key) = match self.key_storage {
-                                               KeyStorage::PrivMode { ref revocation_base_key, ref htlc_base_key, .. } => {
+                                               Storage::Local { ref revocation_base_key, ref htlc_base_key, .. } => {
                                                        (ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, revocation_point, &PublicKey::from_secret_key(&self.secp_ctx, &revocation_base_key))),
                                                        ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, revocation_point, &PublicKey::from_secret_key(&self.secp_ctx, &htlc_base_key))))
                                                },
-                                               KeyStorage::SigsMode { ref revocation_base_key, ref htlc_base_key, .. } => {
+                                               Storage::Watchtower { ref revocation_base_key, ref htlc_base_key, .. } => {
                                                        (ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, revocation_point, &revocation_base_key)),
                                                        ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, revocation_point, &htlc_base_key)))
                                                },
@@ -1072,11 +1143,10 @@ impl ChannelMonitor {
                                                Some(their_htlc_base_key) => ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, revocation_point, &their_htlc_base_key)),
                                        };
 
-
                                        for (idx, outp) in tx.output.iter().enumerate() {
                                                if outp.script_pubkey.is_v0_p2wpkh() {
                                                        match self.key_storage {
-                                                               KeyStorage::PrivMode { ref payment_base_key, .. } => {
+                                                               Storage::Local { ref payment_base_key, .. } => {
                                                                        if let Ok(local_key) = chan_utils::derive_private_key(&self.secp_ctx, &revocation_point, &payment_base_key) {
                                                                                spendable_outputs.push(SpendableOutputDescriptor::DynamicOutputP2WPKH {
                                                                                        outpoint: BitcoinOutPoint { txid: commitment_txid, vout: idx as u32 },
@@ -1084,11 +1154,8 @@ impl ChannelMonitor {
                                                                                        output: outp.clone(),
                                                                                });
                                                                        }
-                                                               }
-                                                               KeyStorage::SigsMode { .. } => {
-                                                                       //TODO: we need to ensure an offline client will generate the event when it
-                                                                       // cames back online after only the watchtower saw the transaction
-                                                               }
+                                                               },
+                                                               Storage::Watchtower { .. } => {}
                                                        }
                                                        break; // Only to_remote ouput is claimable
                                                }
@@ -1102,14 +1169,14 @@ impl ChannelMonitor {
                                                ($sighash_parts: expr, $input: expr, $amount: expr, $preimage: expr) => {
                                                        {
                                                                let (sig, redeemscript) = match self.key_storage {
-                                                                       KeyStorage::PrivMode { ref htlc_base_key, .. } => {
-                                                                               let htlc = &per_commitment_option.unwrap()[$input.sequence as usize];
+                                                                       Storage::Local { ref htlc_base_key, .. } => {
+                                                                               let htlc = &per_commitment_option.unwrap().0[$input.sequence as usize];
                                                                                let redeemscript = chan_utils::get_htlc_redeemscript_with_explicit_keys(htlc, &a_htlc_key, &b_htlc_key, &revocation_pubkey);
                                                                                let sighash = ignore_error!(Message::from_slice(&$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));
                                                                                (self.secp_ctx.sign(&sighash, &htlc_key), redeemscript)
                                                                        },
-                                                                       KeyStorage::SigsMode { .. } => {
+                                                                       Storage::Watchtower { .. } => {
                                                                                unimplemented!();
                                                                        }
                                                                };
@@ -1121,7 +1188,13 @@ impl ChannelMonitor {
                                                }
                                        }
 
-                                       for (idx, htlc) in per_commitment_data.iter().enumerate() {
+                                       for (idx, ref htlc) in per_commitment_data.0.iter().enumerate() {
+                                               let expected_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &a_htlc_key, &b_htlc_key, &revocation_pubkey);
+                                               if htlc.transaction_output_index as usize >= tx.output.len() ||
+                                                               tx.output[htlc.transaction_output_index as usize].value != htlc.amount_msat / 1000 ||
+                                                               tx.output[htlc.transaction_output_index as usize].script_pubkey != expected_script.to_v0_p2wsh() {
+                                                       return (txn_to_broadcast, (commitment_txid, watch_outputs), spendable_outputs); // Corrupted per_commitment_data, fuck this user
+                                               }
                                                if let Some(payment_preimage) = self.payment_preimages.get(&htlc.payment_hash) {
                                                        let input = TxIn {
                                                                previous_output: BitcoinOutPoint {
@@ -1205,14 +1278,14 @@ impl ChannelMonitor {
                        };
                }
 
-               let secret = ignore_error!(self.get_secret(commitment_number));
+               let secret = if let Some(secret) = self.get_secret(commitment_number) { secret } else { return (None, None); };
                let per_commitment_key = ignore_error!(SecretKey::from_slice(&self.secp_ctx, &secret));
                let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
                let revocation_pubkey = match self.key_storage {
-                       KeyStorage::PrivMode { ref revocation_base_key, .. } => {
+                       Storage::Local { ref revocation_base_key, .. } => {
                                ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &PublicKey::from_secret_key(&self.secp_ctx, &revocation_base_key)))
                        },
-                       KeyStorage::SigsMode { ref revocation_base_key, .. } => {
+                       Storage::Watchtower { ref revocation_base_key, .. } => {
                                ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &revocation_base_key))
                        },
                };
@@ -1256,12 +1329,12 @@ impl ChannelMonitor {
                        let sighash_parts = bip143::SighashComponents::new(&spend_tx);
 
                        let sig = match self.key_storage {
-                               KeyStorage::PrivMode { ref revocation_base_key, .. } => {
+                               Storage::Local { ref revocation_base_key, .. } => {
                                        let sighash = ignore_error!(Message::from_slice(&sighash_parts.sighash_all(&spend_tx.input[0], &redeemscript, amount)[..]));
                                        let revocation_key = ignore_error!(chan_utils::derive_private_revocation_key(&self.secp_ctx, &per_commitment_key, &revocation_base_key));
                                        self.secp_ctx.sign(&sighash, &revocation_key)
                                }
-                               KeyStorage::SigsMode { .. } => {
+                               Storage::Watchtower { .. } => {
                                        unimplemented!();
                                }
                        };
@@ -1276,9 +1349,10 @@ impl ChannelMonitor {
                } else { (None, None) }
        }
 
-       fn broadcast_by_local_state(&self, local_tx: &LocalSignedTx, per_commitment_point: &Option<PublicKey>, delayed_payment_base_key: &Option<SecretKey>) -> (Vec<Transaction>, Vec<SpendableOutputDescriptor>) {
+       fn broadcast_by_local_state(&self, local_tx: &LocalSignedTx, per_commitment_point: &Option<PublicKey>, delayed_payment_base_key: &Option<SecretKey>) -> (Vec<Transaction>, Vec<SpendableOutputDescriptor>, Vec<TxOut>) {
                let mut res = Vec::with_capacity(local_tx.htlc_outputs.len());
                let mut spendable_outputs = Vec::with_capacity(local_tx.htlc_outputs.len());
+               let mut watch_outputs = Vec::with_capacity(local_tx.htlc_outputs.len());
 
                macro_rules! add_dynamic_output {
                        ($father_tx: expr, $vout: expr) => {
@@ -1342,24 +1416,27 @@ impl ChannelMonitor {
                                        res.push(htlc_success_tx);
                                }
                        }
+                       watch_outputs.push(local_tx.tx.output[htlc.transaction_output_index as usize].clone());
                }
 
-               (res, spendable_outputs)
+               (res, spendable_outputs, watch_outputs)
        }
 
        /// Attempts to claim any claimable HTLCs in a commitment transaction which was not (yet)
        /// revoked using data in local_claimable_outpoints.
        /// Should not be used if check_spend_revoked_transaction succeeds.
-       fn check_spend_local_transaction(&self, tx: &Transaction, _height: u32) -> (Vec<Transaction>, Vec<SpendableOutputDescriptor>) {
+       fn check_spend_local_transaction(&self, tx: &Transaction, _height: u32) -> (Vec<Transaction>, Vec<SpendableOutputDescriptor>, (Sha256dHash, Vec<TxOut>)) {
                let commitment_txid = tx.txid();
                if let &Some(ref local_tx) = &self.current_local_signed_commitment_tx {
                        if local_tx.txid == commitment_txid {
                                match self.key_storage {
-                                       KeyStorage::PrivMode { ref delayed_payment_base_key, ref latest_per_commitment_point, .. } => {
-                                               return self.broadcast_by_local_state(local_tx, latest_per_commitment_point, &Some(*delayed_payment_base_key));
+                                       Storage::Local { ref delayed_payment_base_key, ref latest_per_commitment_point, .. } => {
+                                               let (local_txn, spendable_outputs, watch_outputs) = self.broadcast_by_local_state(local_tx, latest_per_commitment_point, &Some(*delayed_payment_base_key));
+                                               return (local_txn, spendable_outputs, (commitment_txid, watch_outputs));
                                        },
-                                       KeyStorage::SigsMode { .. } => {
-                                               return self.broadcast_by_local_state(local_tx, &None, &None);
+                                       Storage::Watchtower { .. } => {
+                                               let (local_txn, spendable_outputs, watch_outputs) = self.broadcast_by_local_state(local_tx, &None, &None);
+                                               return (local_txn, spendable_outputs, (commitment_txid, watch_outputs));
                                        }
                                }
                        }
@@ -1367,23 +1444,25 @@ impl ChannelMonitor {
                if let &Some(ref local_tx) = &self.prev_local_signed_commitment_tx {
                        if local_tx.txid == commitment_txid {
                                match self.key_storage {
-                                       KeyStorage::PrivMode { ref delayed_payment_base_key, ref prev_latest_per_commitment_point, .. } => {
-                                               return self.broadcast_by_local_state(local_tx, prev_latest_per_commitment_point, &Some(*delayed_payment_base_key));
+                                       Storage::Local { ref delayed_payment_base_key, ref prev_latest_per_commitment_point, .. } => {
+                                               let (local_txn, spendable_outputs, watch_outputs) = self.broadcast_by_local_state(local_tx, prev_latest_per_commitment_point, &Some(*delayed_payment_base_key));
+                                               return (local_txn, spendable_outputs, (commitment_txid, watch_outputs));
                                        },
-                                       KeyStorage::SigsMode { .. } => {
-                                               return self.broadcast_by_local_state(local_tx, &None, &None);
+                                       Storage::Watchtower { .. } => {
+                                               let (local_txn, spendable_outputs, watch_outputs) = self.broadcast_by_local_state(local_tx, &None, &None);
+                                               return (local_txn, spendable_outputs, (commitment_txid, watch_outputs));
                                        }
                                }
                        }
                }
-               (Vec::new(), Vec::new())
+               (Vec::new(), Vec::new(), (commitment_txid, Vec::new()))
        }
 
        /// Generate a spendable output event when closing_transaction get registered onchain.
        fn check_spend_closing_transaction(&self, tx: &Transaction) -> Option<SpendableOutputDescriptor> {
-               if tx.input[0].sequence == 0xFFFFFFFF && tx.input[0].witness.last().unwrap().len() == 71 {
+               if tx.input[0].sequence == 0xFFFFFFFF && !tx.input[0].witness.is_empty() && tx.input[0].witness.last().unwrap().len() == 71 {
                        match self.key_storage {
-                               KeyStorage::PrivMode { ref shutdown_pubkey, .. } =>  {
+                               Storage::Local { ref shutdown_pubkey, .. } =>  {
                                        let our_channel_close_key_hash = Hash160::from_data(&shutdown_pubkey.serialize());
                                        let shutdown_script = Builder::new().push_opcode(opcodes::All::OP_PUSHBYTES_0).push_slice(&our_channel_close_key_hash[..]).into_script();
                                        for (idx, output) in tx.output.iter().enumerate() {
@@ -1395,7 +1474,7 @@ impl ChannelMonitor {
                                                }
                                        }
                                }
-                               KeyStorage::SigsMode { .. } => {
+                               Storage::Watchtower { .. } => {
                                        //TODO: we need to ensure an offline client will generate the event when it
                                        // cames back online after only the watchtower saw the transaction
                                }
@@ -1410,7 +1489,7 @@ impl ChannelMonitor {
                if let &Some(ref local_tx) = &self.current_local_signed_commitment_tx {
                        let mut res = vec![local_tx.tx.clone()];
                        match self.key_storage {
-                               KeyStorage::PrivMode { ref delayed_payment_base_key, ref prev_latest_per_commitment_point, .. } => {
+                               Storage::Local { ref delayed_payment_base_key, ref prev_latest_per_commitment_point, .. } => {
                                        res.append(&mut self.broadcast_by_local_state(local_tx, prev_latest_per_commitment_point, &Some(*delayed_payment_base_key)).0);
                                },
                                _ => panic!("Can only broadcast by local channelmonitor"),
@@ -1432,7 +1511,15 @@ impl ChannelMonitor {
                                // filters.
                                let prevout = &tx.input[0].previous_output;
                                let mut txn: Vec<Transaction> = Vec::new();
-                               if self.funding_txo.is_none() || (prevout.txid == self.funding_txo.as_ref().unwrap().0.txid && prevout.vout == self.funding_txo.as_ref().unwrap().0.index as u32) {
+                               let funding_txo = match self.key_storage {
+                                       Storage::Local { ref funding_info, .. } => {
+                                               funding_info.clone()
+                                       }
+                                       Storage::Watchtower { .. } => {
+                                               unimplemented!();
+                                       }
+                               };
+                               if funding_txo.is_none() || (prevout.txid == funding_txo.as_ref().unwrap().0.txid && prevout.vout == funding_txo.as_ref().unwrap().0.index as u32) {
                                        let (remote_txn, new_outputs, mut spendable_output) = self.check_spend_remote_transaction(tx, height);
                                        txn = remote_txn;
                                        spendable_outputs.append(&mut spendable_output);
@@ -1440,11 +1527,14 @@ impl ChannelMonitor {
                                                watch_outputs.push(new_outputs);
                                        }
                                        if txn.is_empty() {
-                                               let (remote_txn, mut outputs) = self.check_spend_local_transaction(tx, height);
-                                               spendable_outputs.append(&mut outputs);
-                                               txn = remote_txn;
+                                               let (local_txn, mut spendable_output, new_outputs) = self.check_spend_local_transaction(tx, height);
+                                               spendable_outputs.append(&mut spendable_output);
+                                               txn = local_txn;
+                                               if !new_outputs.1.is_empty() {
+                                                       watch_outputs.push(new_outputs);
+                                               }
                                        }
-                                       if !self.funding_txo.is_none() && txn.is_empty() {
+                                       if !funding_txo.is_none() && txn.is_empty() {
                                                if let Some(spendable_output) = self.check_spend_closing_transaction(tx) {
                                                        spendable_outputs.push(spendable_output);
                                                }
@@ -1469,16 +1559,22 @@ impl ChannelMonitor {
                        if self.would_broadcast_at_height(height) {
                                broadcaster.broadcast_transaction(&cur_local_tx.tx);
                                match self.key_storage {
-                                       KeyStorage::PrivMode { ref delayed_payment_base_key, ref latest_per_commitment_point, .. } => {
-                                               let (txs, mut outputs) = self.broadcast_by_local_state(&cur_local_tx, latest_per_commitment_point, &Some(*delayed_payment_base_key));
-                                               spendable_outputs.append(&mut outputs);
+                                       Storage::Local { ref delayed_payment_base_key, ref latest_per_commitment_point, .. } => {
+                                               let (txs, mut spendable_output, new_outputs) = self.broadcast_by_local_state(&cur_local_tx, latest_per_commitment_point, &Some(*delayed_payment_base_key));
+                                               spendable_outputs.append(&mut spendable_output);
+                                               if !new_outputs.is_empty() {
+                                                       watch_outputs.push((cur_local_tx.txid.clone(), new_outputs));
+                                               }
                                                for tx in txs {
                                                        broadcaster.broadcast_transaction(&tx);
                                                }
                                        },
-                                       KeyStorage::SigsMode { .. } => {
-                                               let (txs, mut outputs) = self.broadcast_by_local_state(&cur_local_tx, &None, &None);
-                                               spendable_outputs.append(&mut outputs);
+                                       Storage::Watchtower { .. } => {
+                                               let (txs, mut spendable_output, new_outputs) = self.broadcast_by_local_state(&cur_local_tx, &None, &None);
+                                               spendable_outputs.append(&mut spendable_output);
+                                               if !new_outputs.is_empty() {
+                                                       watch_outputs.push((cur_local_tx.txid.clone(), new_outputs));
+                                               }
                                                for tx in txs {
                                                        broadcaster.broadcast_transaction(&tx);
                                                }
@@ -1543,13 +1639,6 @@ impl<R: ::std::io::Read> ReadableArgs<R, Arc<Logger>> for (Sha256dHash, ChannelM
                        return Err(DecodeError::UnknownVersion);
                }
 
-               // Technically this can fail and serialize fail a round-trip, but only for serialization of
-               // barely-init'd ChannelMonitors that we can't do anything with.
-               let outpoint = OutPoint {
-                       txid: Readable::read(reader)?,
-                       index: Readable::read(reader)?,
-               };
-               let funding_txo = Some((outpoint, Readable::read(reader)?));
                let commitment_transaction_number_obscure_factor = <U48 as Readable<R>>::read(reader)?.0;
 
                let key_storage = match <u8 as Readable<R>>::read(reader)? {
@@ -1569,7 +1658,14 @@ impl<R: ::std::io::Read> ReadableArgs<R, Arc<Logger>> for (Sha256dHash, ChannelM
                                        1 => Some(Readable::read(reader)?),
                                        _ => return Err(DecodeError::InvalidValue),
                                };
-                               KeyStorage::PrivMode {
+                               // Technically this can fail and serialize fail a round-trip, but only for serialization of
+                               // barely-init'd ChannelMonitors that we can't do anything with.
+                               let outpoint = OutPoint {
+                                       txid: Readable::read(reader)?,
+                                       index: Readable::read(reader)?,
+                               };
+                               let funding_info = Some((outpoint, Readable::read(reader)?));
+                               Storage::Local {
                                        revocation_base_key,
                                        htlc_base_key,
                                        delayed_payment_base_key,
@@ -1577,6 +1673,7 @@ impl<R: ::std::io::Read> ReadableArgs<R, Arc<Logger>> for (Sha256dHash, ChannelM
                                        shutdown_pubkey,
                                        prev_latest_per_commitment_point,
                                        latest_per_commitment_point,
+                                       funding_info,
                                }
                        },
                        _ => return Err(DecodeError::InvalidValue),
@@ -1625,6 +1722,20 @@ 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 {
@@ -1634,7 +1745,12 @@ impl<R: ::std::io::Read> ReadableArgs<R, Arc<Logger>> for (Sha256dHash, ChannelM
                        for _ in 0..outputs_count {
                                outputs.push(read_htlc_in_commitment!());
                        }
-                       if let Some(_) = remote_claimable_outpoints.insert(txid, outputs) {
+                       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!());
+                       }
+                       if let Some(_) = remote_claimable_outpoints.insert(txid, (outputs, sources)) {
                                return Err(DecodeError::InvalidValue);
                        }
                }
@@ -1689,12 +1805,20 @@ impl<R: ::std::io::Read> ReadableArgs<R, Arc<Logger>> for (Sha256dHash, ChannelM
                                        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 {
-                                               htlc_outputs.push((read_htlc_in_commitment!(), Readable::read(reader)?, Readable::read(reader)?));
+                                               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!());
                                        }
 
                                        LocalSignedTx {
                                                txid: tx.txid(),
-                                               tx, revocation_key, a_htlc_key, b_htlc_key, delayed_payment_key, feerate_per_kw, htlc_outputs
+                                               tx, revocation_key, a_htlc_key, b_htlc_key, delayed_payment_key, feerate_per_kw, htlc_outputs, htlc_sources
                                        }
                                }
                        }
@@ -1736,7 +1860,6 @@ impl<R: ::std::io::Read> ReadableArgs<R, Arc<Logger>> for (Sha256dHash, ChannelM
                let destination_script = Readable::read(reader)?;
 
                Ok((last_block_hash.clone(), ChannelMonitor {
-                       funding_txo,
                        commitment_transaction_number_obscure_factor,
 
                        key_storage,
@@ -1798,7 +1921,7 @@ mod tests {
                                        idx -= 1;
                                }
                                assert_eq!(monitor.get_min_seen_secret(), idx + 1);
-                               assert!(monitor.get_secret(idx).is_err());
+                               assert!(monitor.get_secret(idx).is_none());
                        };
                }
 
@@ -1860,7 +1983,7 @@ mod tests {
 
                        secrets.push([0; 32]);
                        secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("c7518c8ae4660ed02894df8976fa1a3659c1a8b4b5bec0c4b872abeba4cb8964").unwrap());
-                       assert_eq!(monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap_err().err,
+                       assert_eq!(monitor.provide_secret(281474976710654, secrets.last().unwrap().clone()).unwrap_err().0,
                                        "Previous secret did not match new one");
                }
 
@@ -1886,7 +2009,7 @@ mod tests {
 
                        secrets.push([0; 32]);
                        secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
-                       assert_eq!(monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap_err().err,
+                       assert_eq!(monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap_err().0,
                                        "Previous secret did not match new one");
                }
 
@@ -1912,7 +2035,7 @@ mod tests {
 
                        secrets.push([0; 32]);
                        secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
-                       assert_eq!(monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap_err().err,
+                       assert_eq!(monitor.provide_secret(281474976710652, secrets.last().unwrap().clone()).unwrap_err().0,
                                        "Previous secret did not match new one");
                }
 
@@ -1958,7 +2081,7 @@ mod tests {
 
                        secrets.push([0; 32]);
                        secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("05cde6323d949933f7f7b78776bcc1ea6d9b31447732e3802e1f7ac44b650e17").unwrap());
-                       assert_eq!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).unwrap_err().err,
+                       assert_eq!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).unwrap_err().0,
                                        "Previous secret did not match new one");
                }
 
@@ -1994,7 +2117,7 @@ mod tests {
 
                        secrets.push([0; 32]);
                        secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("969660042a28f32d9be17344e09374b379962d03db1574df5a8a5a47e19ce3f2").unwrap());
-                       assert_eq!(monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).unwrap_err().err,
+                       assert_eq!(monitor.provide_secret(281474976710650, secrets.last().unwrap().clone()).unwrap_err().0,
                                        "Previous secret did not match new one");
                }
 
@@ -2040,7 +2163,7 @@ mod tests {
 
                        secrets.push([0; 32]);
                        secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("05cde6323d949933f7f7b78776bcc1ea6d9b31447732e3802e1f7ac44b650e17").unwrap());
-                       assert_eq!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).unwrap_err().err,
+                       assert_eq!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).unwrap_err().0,
                                        "Previous secret did not match new one");
                }
 
@@ -2086,7 +2209,7 @@ mod tests {
 
                        secrets.push([0; 32]);
                        secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("05cde6323d949933f7f7b78776bcc1ea6d9b31447732e3802e1f7ac44b650e17").unwrap());
-                       assert_eq!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).unwrap_err().err,
+                       assert_eq!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).unwrap_err().0,
                                        "Previous secret did not match new one");
                }
 
@@ -2132,7 +2255,7 @@ mod tests {
 
                        secrets.push([0; 32]);
                        secrets.last_mut().unwrap()[0..32].clone_from_slice(&hex::decode("a7efbc61aac46d34f77778bac22c8a20c6a46ca460addc49009bda875ec88fa4").unwrap());
-                       assert_eq!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).unwrap_err().err,
+                       assert_eq!(monitor.provide_secret(281474976710648, secrets.last().unwrap().clone()).unwrap_err().0,
                                        "Previous secret did not match new one");
                }
        }
@@ -2143,10 +2266,10 @@ mod tests {
                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 {
                        () => {
                                {
-                                       let dummy_key = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &[42; 32]).unwrap());
                                        TxCreationKeys {
                                                per_commitment_point: dummy_key.clone(),
                                                revocation_key: dummy_key.clone(),
@@ -2214,11 +2337,11 @@ 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]));
-               monitor.provide_latest_remote_commitment_tx_info(&dummy_tx, preimages_slice_to_htlc_outputs!(preimages[5..15]), 281474976710655);
-               monitor.provide_latest_remote_commitment_tx_info(&dummy_tx, preimages_slice_to_htlc_outputs!(preimages[15..20]), 281474976710654);
-               monitor.provide_latest_remote_commitment_tx_info(&dummy_tx, preimages_slice_to_htlc_outputs!(preimages[17..20]), 281474976710653);
-               monitor.provide_latest_remote_commitment_tx_info(&dummy_tx, preimages_slice_to_htlc_outputs!(preimages[18..20]), 281474976710652);
+               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);
                for &(ref preimage, ref hash) in preimages.iter() {
                        monitor.provide_payment_preimage(hash, preimage);
                }
@@ -2240,7 +2363,7 @@ 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]));
+               monitor.provide_latest_local_commitment_tx_info(dummy_tx.clone(), dummy_keys!(), 0, preimages_to_local_htlcs!(preimages[0..5]), Vec::new());
                secret[0..32].clone_from_slice(&hex::decode("2273e227a5b7449b6e70f1fb4652864038b1cbf9cd7c043a7d6456b7fc275ad8").unwrap());
                monitor.provide_secret(281474976710653, secret.clone()).unwrap();
                assert_eq!(monitor.payment_preimages.len(), 12);
@@ -2248,7 +2371,7 @@ 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]));
+               monitor.provide_latest_local_commitment_tx_info(dummy_tx.clone(), dummy_keys!(), 0, preimages_to_local_htlcs!(preimages[0..3]), Vec::new());
                secret[0..32].clone_from_slice(&hex::decode("27cddaa5624534cb6cb9d7da077cf2b22ab21e9b506fd4998a51d54502e99116").unwrap());
                monitor.provide_secret(281474976710652, secret.clone()).unwrap();
                assert_eq!(monitor.payment_preimages.len(), 5);