Merge pull request #649 from jkczyz/2020-06-refactor-chain-listener
[rust-lightning] / lightning / src / ln / channelmanager.rs
index 59d513b396825eb5e86f7fbf0514691829c4f818..353de9240cc3007a010b73d01f4853e9a2c6d909 100644 (file)
@@ -18,7 +18,6 @@
 //! imply it needs to fail HTLCs/payments/channels it manages).
 
 use bitcoin::blockdata::block::BlockHeader;
-use bitcoin::blockdata::transaction::Transaction;
 use bitcoin::blockdata::constants::genesis_block;
 use bitcoin::network::constants::Network;
 
@@ -34,10 +33,12 @@ use bitcoin::secp256k1::Secp256k1;
 use bitcoin::secp256k1::ecdh::SharedSecret;
 use bitcoin::secp256k1;
 
-use chain::chaininterface::{BroadcasterInterface,ChainListener,FeeEstimator};
-use chain::transaction::OutPoint;
+use chain;
+use chain::Watch;
+use chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateErr, HTLC_FAIL_BACK_BUFFER, CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS, ANTI_REORG_DELAY, MonitorEvent};
+use chain::transaction::{OutPoint, TransactionData};
 use ln::channel::{Channel, ChannelError};
-use ln::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateErr, ManyChannelMonitor, HTLC_FAIL_BACK_BUFFER, CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS, ANTI_REORG_DELAY, MonitorEvent};
 use ln::features::{InitFeatures, NodeFeatures};
 use routing::router::{Route, RouteHop};
 use ln::msgs;
@@ -128,7 +129,7 @@ pub(super) enum HTLCForwardInfo {
 
 /// Tracks the inbound corresponding to an outbound HTLC
 #[derive(Clone, PartialEq)]
-pub(super) struct HTLCPreviousHopData {
+pub(crate) struct HTLCPreviousHopData {
        short_channel_id: u64,
        htlc_id: u64,
        incoming_packet_shared_secret: [u8; 32],
@@ -147,7 +148,7 @@ struct ClaimableHTLC {
 
 /// Tracks the inbound corresponding to an outbound HTLC
 #[derive(Clone, PartialEq)]
-pub(super) enum HTLCSource {
+pub(crate) enum HTLCSource {
        PreviousHopData(HTLCPreviousHopData),
        OutboundRoute {
                path: Vec<RouteHop>,
@@ -360,7 +361,7 @@ pub type SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, M, T, F, L> = ChannelManage
 ///
 /// Note that you can be a bit lazier about writing out ChannelManager than you can be with
 /// ChannelMonitors. With ChannelMonitors you MUST write each monitor update out to disk before
-/// returning from ManyChannelMonitor::add_/update_monitor, with ChannelManagers, writing updates
+/// returning from chain::Watch::watch_/update_channel, with ChannelManagers, writing updates
 /// happens out-of-band (and will prevent any other ChannelManager operations from occurring during
 /// the serialization process). If the deserialized version is out-of-date compared to the
 /// ChannelMonitors passed by reference to read(), those channels will be force-closed based on the
@@ -384,7 +385,7 @@ pub type SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, M, T, F, L> = ChannelManage
 /// SimpleArcChannelManager when you require a ChannelManager with a static lifetime, such as when
 /// you're using lightning-net-tokio.
 pub struct ChannelManager<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
-       where M::Target: ManyChannelMonitor<Keys=ChanSigner>,
+       where M::Target: chain::Watch<Keys=ChanSigner>,
         T::Target: BroadcasterInterface,
         K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
         F::Target: FeeEstimator,
@@ -393,7 +394,7 @@ pub struct ChannelManager<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref,
        default_configuration: UserConfig,
        genesis_hash: BlockHash,
        fee_estimator: F,
-       monitor: M,
+       chain_monitor: M,
        tx_broadcaster: T,
 
        #[cfg(test)]
@@ -697,7 +698,7 @@ macro_rules! maybe_break_monitor_err {
 }
 
 impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelManager<ChanSigner, M, T, K, F, L>
-       where M::Target: ManyChannelMonitor<Keys=ChanSigner>,
+       where M::Target: chain::Watch<Keys=ChanSigner>,
         T::Target: BroadcasterInterface,
         K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
         F::Target: FeeEstimator,
@@ -717,18 +718,14 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
        ///
        /// Users need to notify the new ChannelManager when a new block is connected or
        /// disconnected using its `block_connected` and `block_disconnected` methods.
-       /// However, rather than calling these methods directly, the user should register
-       /// the ChannelManager as a listener to the BlockNotifier and call the BlockNotifier's
-       /// `block_(dis)connected` methods, which will notify all registered listeners in one
-       /// go.
-       pub fn new(network: Network, fee_est: F, monitor: M, tx_broadcaster: T, logger: L, keys_manager: K, config: UserConfig, current_blockchain_height: usize) -> Self {
+       pub fn new(network: Network, fee_est: F, chain_monitor: M, tx_broadcaster: T, logger: L, keys_manager: K, config: UserConfig, current_blockchain_height: usize) -> Self {
                let secp_ctx = Secp256k1::new();
 
                ChannelManager {
                        default_configuration: config.clone(),
                        genesis_hash: genesis_block(network).header.block_hash(),
                        fee_estimator: fee_est,
-                       monitor,
+                       chain_monitor,
                        tx_broadcaster,
 
                        latest_block_height: AtomicUsize::new(current_blockchain_height),
@@ -903,7 +900,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                        // force-closing. The monitor update on the required in-memory copy should broadcast
                        // the latest local state, which is the best we can do anyway. Thus, it is safe to
                        // ignore the result here.
-                       let _ = self.monitor.update_monitor(funding_txo, monitor_update);
+                       let _ = self.chain_monitor.update_channel(funding_txo, monitor_update);
                }
        }
 
@@ -1283,7 +1280,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                                        }, onion_packet, &self.logger), channel_state, chan)
                                } {
                                        Some((update_add, commitment_signed, monitor_update)) => {
-                                               if let Err(e) = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update) {
+                                               if let Err(e) = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), monitor_update) {
                                                        maybe_break_monitor_err!(self, e, channel_state, chan, RAACommitmentOrder::CommitmentFirst, false, true);
                                                        // Note that MonitorUpdateFailed here indicates (per function docs)
                                                        // that we will resend the commitment update once monitor updating
@@ -1679,7 +1676,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                                                                        continue;
                                                                }
                                                        };
-                                                       if let Err(e) = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update) {
+                                                       if let Err(e) = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), monitor_update) {
                                                                handle_errors.push((chan.get().get_counterparty_node_id(), handle_monitor_err!(self, e, channel_state, chan, RAACommitmentOrder::CommitmentFirst, false, true)));
                                                                continue;
                                                        }
@@ -2089,7 +2086,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                        match chan.get_mut().get_update_fulfill_htlc_and_commit(prev_hop.htlc_id, payment_preimage, &self.logger) {
                                Ok((msgs, monitor_option)) => {
                                        if let Some(monitor_update) = monitor_option {
-                                               if let Err(e) = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update) {
+                                               if let Err(e) = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), monitor_update) {
                                                        if was_frozen_for_monitor {
                                                                assert!(msgs.is_none());
                                                        } else {
@@ -2173,7 +2170,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
        /// exists largely only to prevent races between this and concurrent update_monitor calls.
        ///
        /// Thus, the anticipated use is, at a high level:
-       ///  1) You register a ManyChannelMonitor with this ChannelManager,
+       ///  1) You register a chain::Watch with this ChannelManager,
        ///  2) it stores each update to disk, and begins updating any remote (eg watchtower) copies of
        ///     said ChannelMonitors as it can, returning ChannelMonitorUpdateErr::TemporaryFailures
        ///     any time it cannot do so instantly,
@@ -2314,7 +2311,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
        }
 
        fn internal_funding_created(&self, counterparty_node_id: &PublicKey, msg: &msgs::FundingCreated) -> Result<(), MsgHandleErrInternal> {
-               let ((funding_msg, monitor_update), mut chan) = {
+               let ((funding_msg, monitor), mut chan) = {
                        let mut channel_lock = self.channel_state.lock().unwrap();
                        let channel_state = &mut *channel_lock;
                        match channel_state.by_id.entry(msg.temporary_channel_id.clone()) {
@@ -2328,8 +2325,8 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                        }
                };
                // Because we have exclusive ownership of the channel here we can release the channel_state
-               // lock before add_monitor
-               if let Err(e) = self.monitor.add_monitor(monitor_update.get_funding_txo().0, monitor_update) {
+               // lock before watch_channel
+               if let Err(e) = self.chain_monitor.watch_channel(monitor.get_funding_txo().0, monitor) {
                        match e {
                                ChannelMonitorUpdateErr::PermanentFailure => {
                                        // Note that we reply with the new channel_id in error messages if we gave up on the
@@ -2377,7 +2374,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                                                Ok(update) => update,
                                                Err(e) => try_chan_entry!(self, Err(e), channel_state, chan),
                                        };
-                                       if let Err(e) = self.monitor.add_monitor(chan.get().get_funding_txo().unwrap(), monitor) {
+                                       if let Err(e) = self.chain_monitor.watch_channel(chan.get().get_funding_txo().unwrap(), monitor) {
                                                return_monitor_err!(self, e, channel_state, chan, RAACommitmentOrder::RevokeAndACKFirst, false, false);
                                        }
                                        (chan.get().get_funding_txo().unwrap(), chan.get().get_user_id())
@@ -2647,13 +2644,13 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                                                Err((None, e)) => try_chan_entry!(self, Err(e), channel_state, chan),
                                                Err((Some(update), e)) => {
                                                        assert!(chan.get().is_awaiting_monitor_update());
-                                                       let _ = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), update);
+                                                       let _ = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), update);
                                                        try_chan_entry!(self, Err(e), channel_state, chan);
                                                        unreachable!();
                                                },
                                                Ok(res) => res
                                        };
-                               if let Err(e) = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update) {
+                               if let Err(e) = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), monitor_update) {
                                        return_monitor_err!(self, e, channel_state, chan, RAACommitmentOrder::RevokeAndACKFirst, true, commitment_signed.is_some());
                                        //TODO: Rebroadcast closing_signed if present on monitor update restoration
                                }
@@ -2735,7 +2732,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                                        let (commitment_update, pending_forwards, pending_failures, closing_signed, monitor_update, htlcs_to_fail_in) =
                                                break_chan_entry!(self, chan.get_mut().revoke_and_ack(&msg, &self.fee_estimator, &self.logger), channel_state, chan);
                                        htlcs_to_fail = htlcs_to_fail_in;
-                                       if let Err(e) = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update) {
+                                       if let Err(e) = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), monitor_update) {
                                                if was_frozen_for_monitor {
                                                        assert!(commitment_update.is_none() && closing_signed.is_none() && pending_forwards.is_empty() && pending_failures.is_empty());
                                                        break Err(MsgHandleErrInternal::ignore_no_close("Previous monitor update failure prevented responses to RAA".to_owned()));
@@ -2860,7 +2857,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                                let (funding_locked, revoke_and_ack, commitment_update, monitor_update_opt, mut order, shutdown) =
                                        try_chan_entry!(self, chan.get_mut().channel_reestablish(msg, &self.logger), channel_state, chan);
                                if let Some(monitor_update) = monitor_update_opt {
-                                       if let Err(e) = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update) {
+                                       if let Err(e) = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), monitor_update) {
                                                // channel_reestablish doesn't guarantee the order it returns is sensical
                                                // for the messages it returns, but if we're setting what messages to
                                                // re-transmit on monitor update success, we need to make sure it is sane.
@@ -2947,7 +2944,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                                        if let Some((update_fee, commitment_signed, monitor_update)) =
                                                        break_chan_entry!(self, chan.get_mut().send_update_fee_and_commit(feerate_per_kw, &self.logger), channel_state, chan)
                                        {
-                                               if let Err(_e) = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update) {
+                                               if let Err(_e) = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), monitor_update) {
                                                        unimplemented!();
                                                }
                                                channel_state.pending_msg_events.push(events::MessageSendEvent::UpdateHTLCs {
@@ -2973,11 +2970,11 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                }
        }
 
-       /// Process pending events from the ManyChannelMonitor.
+       /// Process pending events from the `chain::Watch`.
        fn process_pending_monitor_events(&self) {
                let mut failed_channels = Vec::new();
                {
-                       for monitor_event in self.monitor.get_and_clear_pending_monitor_events() {
+                       for monitor_event in self.chain_monitor.release_pending_monitor_events() {
                                match monitor_event {
                                        MonitorEvent::HTLCEvent(htlc_update) => {
                                                if let Some(preimage) = htlc_update.payment_preimage {
@@ -3017,7 +3014,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
 }
 
 impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> MessageSendEventsProvider for ChannelManager<ChanSigner, M, T, K, F, L>
-       where M::Target: ManyChannelMonitor<Keys=ChanSigner>,
+       where M::Target: chain::Watch<Keys=ChanSigner>,
         T::Target: BroadcasterInterface,
         K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
         F::Target: FeeEstimator,
@@ -3036,7 +3033,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
 }
 
 impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> EventsProvider for ChannelManager<ChanSigner, M, T, K, F, L>
-       where M::Target: ManyChannelMonitor<Keys=ChanSigner>,
+       where M::Target: chain::Watch<Keys=ChanSigner>,
         T::Target: BroadcasterInterface,
         K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
         F::Target: FeeEstimator,
@@ -3054,17 +3051,17 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
        }
 }
 
-impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send, T: Deref + Sync + Send, K: Deref + Sync + Send, F: Deref + Sync + Send, L: Deref + Sync + Send>
-       ChainListener for ChannelManager<ChanSigner, M, T, K, F, L>
-       where M::Target: ManyChannelMonitor<Keys=ChanSigner>,
+impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelManager<ChanSigner, M, T, K, F, L>
+       where M::Target: chain::Watch<Keys=ChanSigner>,
         T::Target: BroadcasterInterface,
         K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
         F::Target: FeeEstimator,
-                               L::Target: Logger,
+        L::Target: Logger,
 {
-       fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[usize]) {
+       /// Updates channel state based on transactions seen in a connected block.
+       pub fn block_connected(&self, header: &BlockHeader, txdata: &TransactionData, height: u32) {
                let header_hash = header.block_hash();
-               log_trace!(self.logger, "Block {} at height {} connected with {} txn matched", header_hash, height, txn_matched.len());
+               log_trace!(self.logger, "Block {} at height {} connected", header_hash, height);
                let _ = self.total_consistency_lock.read().unwrap();
                let mut failed_channels = Vec::new();
                let mut timed_out_htlcs = Vec::new();
@@ -3074,7 +3071,7 @@ impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send, T: Deref + Sync + Send, K:
                        let short_to_id = &mut channel_state.short_to_id;
                        let pending_msg_events = &mut channel_state.pending_msg_events;
                        channel_state.by_id.retain(|_, channel| {
-                               let res = channel.block_connected(header, height, txn_matched, indexes_of_txn_matched);
+                               let res = channel.block_connected(header, txdata, height);
                                if let Ok((chan_res, mut timed_out_pending_htlcs)) = res {
                                        for (source, payment_hash) in timed_out_pending_htlcs.drain(..) {
                                                let chan_update = self.get_channel_update(&channel).map(|u| u.encode_with_len()).unwrap(); // Cannot add/recv HTLCs before we have a short_id so unwrap is safe
@@ -3107,7 +3104,7 @@ impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send, T: Deref + Sync + Send, K:
                                        return false;
                                }
                                if let Some(funding_txo) = channel.get_funding_txo() {
-                                       for tx in txn_matched {
+                                       for &(_, tx) in txdata.iter() {
                                                for inp in tx.input.iter() {
                                                        if inp.previous_output == funding_txo.into_bitcoin_outpoint() {
                                                                log_trace!(self.logger, "Detected channel-closing tx {} spending {}:{}, closing channel {}", tx.txid(), inp.previous_output.txid, inp.previous_output.vout, log_bytes!(channel.channel_id()));
@@ -3173,8 +3170,11 @@ impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send, T: Deref + Sync + Send, K:
                }
        }
 
-       /// We force-close the channel without letting our counterparty participate in the shutdown
-       fn block_disconnected(&self, header: &BlockHeader, _: u32) {
+       /// Updates channel state based on a disconnected block.
+       ///
+       /// If necessary, the channel may be force-closed without letting the counterparty participate
+       /// in the shutdown.
+       pub fn block_disconnected(&self, header: &BlockHeader) {
                let _ = self.total_consistency_lock.read().unwrap();
                let mut failed_channels = Vec::new();
                {
@@ -3209,7 +3209,7 @@ impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send, T: Deref + Sync + Send, K:
 
 impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send, T: Deref + Sync + Send, K: Deref + Sync + Send, F: Deref + Sync + Send, L: Deref + Sync + Send>
        ChannelMessageHandler for ChannelManager<ChanSigner, M, T, K, F, L>
-       where M::Target: ManyChannelMonitor<Keys=ChanSigner>,
+       where M::Target: chain::Watch<Keys=ChanSigner>,
         T::Target: BroadcasterInterface,
         K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
         F::Target: FeeEstimator,
@@ -3652,7 +3652,7 @@ impl Readable for HTLCForwardInfo {
 }
 
 impl<ChanSigner: ChannelKeys + Writeable, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> Writeable for ChannelManager<ChanSigner, M, T, K, F, L>
-       where M::Target: ManyChannelMonitor<Keys=ChanSigner>,
+       where M::Target: chain::Watch<Keys=ChanSigner>,
         T::Target: BroadcasterInterface,
         K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
         F::Target: FeeEstimator,
@@ -3732,11 +3732,10 @@ impl<ChanSigner: ChannelKeys + Writeable, M: Deref, T: Deref, K: Deref, F: Deref
 /// 3) Register all relevant ChannelMonitor outpoints with your chain watch mechanism using
 ///    ChannelMonitor::get_monitored_outpoints and ChannelMonitor::get_funding_txo().
 /// 4) Reconnect blocks on your ChannelMonitors.
-/// 5) Move the ChannelMonitors into your local ManyChannelMonitor.
+/// 5) Move the ChannelMonitors into your local chain::Watch.
 /// 6) Disconnect/connect blocks on the ChannelManager.
-/// 7) Register the new ChannelManager with your ChainWatchInterface.
 pub struct ChannelManagerReadArgs<'a, ChanSigner: 'a + ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
-       where M::Target: ManyChannelMonitor<Keys=ChanSigner>,
+       where M::Target: chain::Watch<Keys=ChanSigner>,
         T::Target: BroadcasterInterface,
         K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
         F::Target: FeeEstimator,
@@ -3750,12 +3749,12 @@ pub struct ChannelManagerReadArgs<'a, ChanSigner: 'a + ChannelKeys, M: Deref, T:
        ///
        /// No calls to the FeeEstimator will be made during deserialization.
        pub fee_estimator: F,
-       /// The ManyChannelMonitor for use in the ChannelManager in the future.
+       /// The chain::Watch for use in the ChannelManager in the future.
        ///
-       /// No calls to the ManyChannelMonitor will be made during deserialization. It is assumed that
+       /// No calls to the chain::Watch will be made during deserialization. It is assumed that
        /// you have deserialized ChannelMonitors separately and will add them to your
-       /// ManyChannelMonitor after deserializing this ChannelManager.
-       pub monitor: M,
+       /// chain::Watch after deserializing this ChannelManager.
+       pub chain_monitor: M,
 
        /// The BroadcasterInterface which will be used in the ChannelManager in the future and may be
        /// used to broadcast the latest local commitment transactions of channels which must be
@@ -3785,7 +3784,7 @@ pub struct ChannelManagerReadArgs<'a, ChanSigner: 'a + ChannelKeys, M: Deref, T:
 
 impl<'a, ChanSigner: 'a + ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                ChannelManagerReadArgs<'a, ChanSigner, M, T, K, F, L>
-       where M::Target: ManyChannelMonitor<Keys=ChanSigner>,
+       where M::Target: chain::Watch<Keys=ChanSigner>,
                T::Target: BroadcasterInterface,
                K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
                F::Target: FeeEstimator,
@@ -3794,10 +3793,10 @@ impl<'a, ChanSigner: 'a + ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L
        /// Simple utility function to create a ChannelManagerReadArgs which creates the monitor
        /// HashMap for you. This is primarily useful for C bindings where it is not practical to
        /// populate a HashMap directly from C.
-       pub fn new(keys_manager: K, fee_estimator: F, monitor: M, tx_broadcaster: T, logger: L, default_config: UserConfig,
+       pub fn new(keys_manager: K, fee_estimator: F, chain_monitor: M, tx_broadcaster: T, logger: L, default_config: UserConfig,
                        mut channel_monitors: Vec<&'a mut ChannelMonitor<ChanSigner>>) -> Self {
                Self {
-                       keys_manager, fee_estimator, monitor, tx_broadcaster, logger, default_config,
+                       keys_manager, fee_estimator, chain_monitor, tx_broadcaster, logger, default_config,
                        channel_monitors: channel_monitors.drain(..).map(|monitor| { (monitor.get_funding_txo().0, monitor) }).collect()
                }
        }
@@ -3807,7 +3806,7 @@ impl<'a, ChanSigner: 'a + ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L
 // SipmleArcChannelManager type:
 impl<'a, ChanSigner: ChannelKeys + Readable, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
        ReadableArgs<ChannelManagerReadArgs<'a, ChanSigner, M, T, K, F, L>> for (BlockHash, Arc<ChannelManager<ChanSigner, M, T, K, F, L>>)
-       where M::Target: ManyChannelMonitor<Keys=ChanSigner>,
+       where M::Target: chain::Watch<Keys=ChanSigner>,
         T::Target: BroadcasterInterface,
         K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
         F::Target: FeeEstimator,
@@ -3821,7 +3820,7 @@ impl<'a, ChanSigner: ChannelKeys + Readable, M: Deref, T: Deref, K: Deref, F: De
 
 impl<'a, ChanSigner: ChannelKeys + Readable, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
        ReadableArgs<ChannelManagerReadArgs<'a, ChanSigner, M, T, K, F, L>> for (BlockHash, ChannelManager<ChanSigner, M, T, K, F, L>)
-       where M::Target: ManyChannelMonitor<Keys=ChanSigner>,
+       where M::Target: chain::Watch<Keys=ChanSigner>,
         T::Target: BroadcasterInterface,
         K::Target: KeysInterface<ChanKeySigner = ChanSigner>,
         F::Target: FeeEstimator,
@@ -3933,7 +3932,7 @@ impl<'a, ChanSigner: ChannelKeys + Readable, M: Deref, T: Deref, K: Deref, F: De
                let channel_manager = ChannelManager {
                        genesis_hash,
                        fee_estimator: args.fee_estimator,
-                       monitor: args.monitor,
+                       chain_monitor: args.chain_monitor,
                        tx_broadcaster: args.tx_broadcaster,
 
                        latest_block_height: AtomicUsize::new(latest_block_height as usize),